[0001]CROSS-REFERENCE TO RELATED APPLICATIONS
[0002]This national stage application claims priority to Japanese Patent Application No. 2011-103296 filed on May 2, 2011, which is incorporated herein in its entirety.
[0003]TECHNICAL FIELD
[0004]The present invention relates to a magnetic refrigerator, and especially relates to a magnetic refrigerator that transports heat of multiple magnetic bodies through heat conduction of the solid material by separately applying magnetism to the multiple magnetic bodies of the same material to thereby exhibit a magnetocaloric effect.
[0005]BACKGROUND
[0006]Conventionally, the majority of the heating and cooling or air conditioning devices operating in room temperature range such as refrigerators, freezers, and air conditioners take advantage of the thermal conductivity of a gas refrigerant like chlorofluorocarbon (CFC) gas and its alternatives. More recently, the problem of ozone depletion caused by the discharge of Freon™ gas, and further, the effects of global warming due to discharge of alternative Freon™ have been realized. Therefore, the development of the air conditioning device is strongly desired, which is clean and innovative with high heat transfer capacity as an alternative to the refrigerator using the gaseous refrigerant and causing the high environmental loads due to use of CFC or its alternatives.
[0007]Against this background, air conditioning technology that is attracting attention recently is a magnetic heating and cooling technology. Some of the magnetic material, when the magnitude of the magnetic field applied to the magnetic body is changed, varies its own temperature in response to that change, through so-called magnetocaloric effect. The magnetic conditioning device technology is directed to such technology for transporting heat by using a magnetic material expressing the magneto-caloric effect.
[0008]For a refrigerator utilizing the magnetic refrigeration technique, for example, a magnetic refrigerator such as that described in Japanese Patent Application No. JP-A No. 2007-147209 transports heat by using heat conduction of solid material. This magnetic refrigerator causes to conduct heat by the configuration described below.
[0009]A positive magnetic member that increases in temperature when applied with magnetism or magnetic field and a negative magnetic member that decreases in temperature when applied with magnetism are alternately arranged at predetermined intervals. A pair of the positive and the negative magnetic members constitute a magnetic member block. A magnetic member unit is formed by arranging a plurality of the magnetic blocks annually. A heat conducting member for selectively inserting into or removing from between the positive and negative magnetic members arranged on the magnetic member unit is disposed between the positive and negative magnetic members. A magnetic circuit is formed by arranging permanent magnets disposed on a hub-shaped rotating member which is concentric with and has substantially the same inner and outer diameters as this magnetic member unit. Further, the rotating member on which permanent magnets are disposed is disposed so as to face the magnetic members and is caused to rotate relative to the magnetic member unit. By this rotation of the rotating member, the positive magnetic member and the negative magnetic member are simultaneously applied with magnetism and the magnetism is then removed. The heat conducting member is selectively inserted into or removed from between the positive and negative magnetic members at predetermined timing in accordance with the rotation of the rotating member. Consequently, the heat generated by the magnetic members through the magnetocaloric effect is transported via the heat conducting member in a direction of the arranged magnetic members. However, in this case, it is necessary to use two different, i.e. positive and negative magnetic members.
[0010]In general, the magnitude of the magnetocaloric effect of the positive magnetic member and that of the negative magnetic member are different from each other. Specifically, the magnetocaloric effect of the negative magnetic material is small compared to the magnetocaloric effect of the positive magnetic material. Therefore, in the case of a magnetic refrigerator using a magnetic body of two different, positive and negative members, since it is impossible to obtain a uniform magnetocaloric effect, thus the heat transfer efficiency of the magnetic refrigerator overall is poor. It is possible to increase the heat transfer efficiency when a uniform magnetocaloric effect is obtained. Thus, there is room for improvement in this respect. Further, the material of the negative magnetic material is relatively of rare materials as compared to the material of the positive magnetic material, the magnetic refrigerator becomes more expensive.
[0011]Furthermore, since the magnetic circuit applying or removing a magnetic field simultaneously the two, i.e. positive and negative materials is large, a large and heavy magnetic refrigerator is the result. If the weight of the magnetic circuit can be smaller, it is possible to reduce the size of the magnetic refrigerator and to lower the cost and weight. In this regard, there is further room for improvement.
[0012]BRIEF SUMMARY
[0013]The present invention has been created in order to solve the various problems described above. The thermal transport capability and thermal transport efficiency are improved. Further, the present invention is intended to provide a magnetic refrigerator capable of realizing miniaturization, weight reduction, and cost reduction.
[0014]The magnetic refrigerator according to the present invention to achieve the objective described above is provided with a magnetic body disposed or arranged plate, a low-temperature side heat exchange portion, a high-temperature side heat exchange portion, a magnet/heat conduction unit, and a driving unit.
[0015]On the magnetic body arranged plate, a plurality of magnetic members of the same material are disposed in row with a space or gap there between to form a magnetic body unit, and a plurality of the magnetic body units are disposed side by side with a space or gap there between in a direction crossing the direction along which the magnetic members are disposed. At one end of each magnetic body unit is disposed a low-temperature heat exchange unit while at the other end is disposed a high-temperature heat exchange unit, respectively.
[0016]On the magnet/thermal conductive member, a plurality of magnetism applying parts and heat conducting members are disposed to face the magnetic body arranged plate.
[0017]To the magnet/heat conductive member is arranged a magnetism applying unit that is configured to apply magnetism separately on the magnetic members of each magnetic body unit disposed on the magnetic body arranged plate. In addition, a heat conductive member is disposed to conduct the heat generated at each magnetic body unit from the low-temperature side heat exchange unit to the high-temperature side heat exchange unit.
[0018]The driving unit is configured to drive at least one of the magnetic body arranged plate and the magnet/heat conductive member arranged plate so as to move the magnetic body arranged plate relative to the magnet/heat conductive member arranged plate in the arranged direction of the magnetic body units.
[0019]When the magnetic body arranged plate is relatively moved to the magnet/heat conductive member arranged plate in the arrangement direction of the magnetic body unit by the driving unit, the heat generated by each magnetic body unit is transported from the low-temperature side heat exchange unit to the high temperature heat exchange unit.
[0020]According to the magnetic refrigerator according to the present invention configured as described above, since, by exhibiting the magnetocaloric effect by applying a magnetic individually to a plurality of magnetic members of the same material, heat of the plurality of magnetic members is transported by taking advantage of heat conductively of the solid material, the heat transport capability and the heat transport efficiency are increased and a refrigerator of smaller, lighter, lower cost can be realized.
[0021]BRIEF DESCRIPTION OF THE DRAWINGS The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: FIGS. 1A and 1B together are a principle diagram of a magnetic refrigeration applicable to the present invention, where FIG. 1A is one state and FIG. 1B is another state, the states reciprocally alternating; FIG. 2 is a graph showing the effect of magnetic refrigeration according to the present invention; FIGS. 3A-3E together are a principle diagram for explaining how heat moves in a first embodiment, with FIGS. 3A-3E each illustrating a phase of the change in heat; FIG. 4 is a top view showing a schematic configuration of a magnetic refrigerator according to the first embodiment; FIG. 5A is a top view of the heat exchange unit support plate constituting the magnetic refrigerator shown in FIG. 4 ; FIG. 5B is a top view of the magnetic member arranged plate constituting the magnetic refrigerator shown in FIG. 4 ; FIG. 5C is a top view of the magnet/heat conductive member arranged or disposed plate constituting the magnetic refrigerator shown in FIG. 4 ; FIG. 6 is an exploded cross-sectional view of the magnetic refrigerator shown in FIG. 4 ; FIGS. 7A and 7B together are a schematic view for explaining a state in which heat moves when rotating the magnet/heat conductive member arranged or disposed plate of the magnetic refrigerator between FIG. 7A and FIG. 7B according to the first embodiment; FIG. 8 is a diagram explaining the operation of the magnetic refrigerator according to the first embodiment; FIG. 9A is an exploded cross-sectional view of the magnetic refrigerator according to a second embodiment, with FIG. 9B being an exploded view of member 30 A of FIG. 9A ; FIG. 10 is a diagram explaining the operation of the magnetic refrigerator according to the second embodiment; FIG. 11 is an exploded cross-sectional view of the magnetic refrigerator according to a third embodiment; FIG. 12 is an exploded cross-sectional view of the magnetic refrigerator according to a fourth embodiment; and FIG. 13 is a schematic view for explaining a state in which heat moves when rotating the annular magnetic member arranged or disposed plate of the magnetic refrigerator according to the fourth embodiment.
[0022]DETAILED DESCRIPTION
[0023]In the following, description is made of embodiments of the magnetic refrigerator according to the present invention. First, the principle of magnetic refrigeration applied to the present invention is now described in detail with respect to FIGS. 1A and 1B . With respect to the magnetic members 10 A- 10 F, positive magnetic members are used as the magnetic members of the same and identical material and thus exhibit the same type of magnetocaloric effect.
[0024]A magnetic body block 100 A is formed by the magnetic members 10 A, 10 B, a magnetic body block 100 B by the magnetic members 10 C, 10 D, and a magnetic body block 100 C is formed by the magnetic members 10 E, 10 F. Further, a magnetic body unit 200 is formed by the magnetic body blocks 100 A to 100 C.
[0025]A magnetic circuit 20 A, 20 B, a magnetic circuit 20 C, 20 D, and magnetic circuit 20 E, 20 F are reciprocal between the magnetic members 10 A- 10 F. In other words, the state in FIG. 1A transfers to FIG. 1B when the magnetic circuit 20 A, 20 B moves from the magnetic member 10 A to 10 B, the magnetic circuit 20 C, 20 D from the magnetic member 10 C to 10 D, and the magnetic circuit 20 E, 20 F from the magnetic member 10 E to 10 F, simultaneously. The state in FIG. 1B returns to the state in FIG. 1A when the magnetic circuit 20 A, 20 B moves from the magnetic member 10 B to 10 A, the magnetic circuits 20 C, 20 D from the magnetic member 10 D to 10 C, and the magnetic circuit 20 E, 20 F from the magnetic member 10 F to 10 E, at the same time. Therefore, by the reciprocal movement of the magnetic circuit, the states in FIG. 1A and FIG. 1B are repeated alternately.
[0026]Here, a plurality of the magnetic members 10 A- 10 F are composed by using only either the positive magnetic members which generate heat when applied with magnetism by the magnetic circuits 20 A, 20 B to the magnetic circuit 20 E, 20 F and absorb heat with the magnetism removed, or the negative magnetic members which absorb energy when applied with magnetism and generate heat at removal of the magnetism. The magnetocaloric effects are opposite from each other between the positive magnetic body and the negative magnetic body so that the type of magnetocaloric effects are different. For the case illustrated in FIGS. 1A and 1B , the positive magnetic body is used which is inexpensive compared to a negative magnetic body. The negative magnetic body must be manufactured from a rare magnetic material and is costly. Further, the magnitude of the magnetocaloric effect of the negative magnetic material is smaller than the magnitude of the magnetocaloric effect of the positive magnetic material.
[0027]The magnetic circuits 20 A, 20 B- 20 E, and 20 F are provided with permanent magnets (not shown). With each of magnetic circuits 20 A, 20 B, 20 C, 20 D, and 20 E, 20 F united to reciprocate in the lateral direction of the drawing, a magnetic will be applied separately or individually to the magnetic members 10 A- 10 F.
[0028]The heat conducting members 30 A- 30 G conduct the heat generated by the magnetic members 10 A- 10 F through magnetocaloric effect from the low-temperature side heat exchange unit 40 A toward the high-temperature side heat exchange unit 40 B. The heat conductive member 30 A is configured to selectively insert into or remove from between the low-temperature side heat exchange unit 40 A and the adjacent magnetic member 10 A to establish mechanical connection there between. The heat conductive member 30 B is configured to selectively insert into and remove from between magnetic members 10 A, 10 B to establish a mechanical connection. Similarly, the heat conductive members 30 , 30 D, 30 E, and 30 F are selectively inserted into or removed from between the magnetic members 10 B and 10 C, the magnetic members 10 C and 10 D, magnetic members 10 D and 10 E, and the magnetic members 10 E and 10 F to establish respective mechanical connection. The heat conductive member 300 is configured to be selectively inserted into and removed from between the magnetic member 10 F and the high-temperature side heat exchange unit 40 B to establish a mechanical contact there between. The heat conductive members 30 B, 30 D, and 30 F are configured to be inserted or removed from between the magnetic members 10 A and 10 B, the magnetic members 10 C and 10 D, and the magnetic members 10 E and 10 F at the same timing to establish mechanical connection. Also, the heat conductive members 30 A, 30 C, 30 E, and 30 G are configured to insert and remove from between the low-temperature side heat exchange unit 40 A and the magnetic member 10 A, between the magnetic members 10 B and 10 C, between the magnetic members 10 D and 10 E, and between the magnetic member 10 F and the high-temperature side heat exchange unit 40 B at the same timing to establish a mechanical connection. The heat conductive members 30 B, 30 D, and 30 F and the heat conductive members 30 A, 30 C, 30 E, and 30 G are inserted or removed by turns or alternately.
[0029]As shown in FIG. 1A , the magnetic circuit 20 A, 20 B is positioned at the magnetic member 10 A of the magnetic body block 100 A, the magnetic circuit 20 C, 20 D at the magnetic member 10 C of the magnetic body block 100 B, and the magnetic circuit 20 E, 20 F at the magnetic member 10 E of the magnetic body block 100 C, respectively. At this time, the magnetic members 10 A, 10 C, and 10 E are applied with magnetism, while the magnetic members 10 B, 10 D, 10 F are not applied with magnetism but removed. In this instance, the magnetic members 10 A, 10 C, and 10 E generate heat. At the same time, the heat conductive member 30 B is inserted between the magnetic member 10 C and 10 D, the heat conductive member 30 D between the magnetic members 10 C and 10 D, and the heat conductive member 30 F between the magnetic members 10 E and 10 F, respectively. Thus, heat conduction takes place between adjacent magnetic members in each magnetic body block. In other words, the heat generated by the magnetic members 10 A, 10 C and 10 E through magnetocaloric effect is transported to the magnetic members 10 B, 10 D, and 10 F, respectively. Further, at this instance, the heat conductive member 30 A and 30 G are not inserted between the low-temperature heat exchange unit 40 A and the magnetic member 10 A or between the high-temperature side heat exchange unit 40 B and the magnetic member 10 F. Moreover, the heat conductive members 30 C and 30 E for performing heat conduction between the magnetic body blocks are not inserted between the magnetic members 10 B and 10 C, or between the magnetic members 10 D and 10 E, either.
[0030]Next, as shown in FIG. 1B , the magnetic circuit 20 A, 20 B is positioned at the magnetic member 10 B of the magnetic body block 100 A, the magnetic circuit 20 C, 20 D at the magnetic member 10 D of the magnetic block 100 B, and the magnetic circuit 20 E, 20 F at the magnetic member 10 F of the magnetic body block 100 C, respectively. In this instance, the magnetic members 10 B, 10 D, and 10 F are applied with magnetism while the magnetic members 10 A, 10 C, and 10 E are not magnetized but free from magnetism. In this instance, the magnetic members 10 B, 10 D, and 10 F generate heat. Further, the heat conductive member 30 A is inserted between the low-temperature side heat exchange unit 40 A and the magnetic member 10 A, the heat conductive member 30 C between the magnetic member 10 B and 10 C, the heat conductive member 30 E between the magnetic members 10 D and 10 E, and the heat conductive member 30 G between the magnetic members 10 F and the high-temperature heat exchange unit 40 B, respectively. Thus, between the low-temperature side heat exchange unit 40 A, the high-temperature side heat exchange unit 40 B and the magnetic members 10 A, 10 F each positioned at both ends of the magnetic body unit 200 , heat conduction takes place. In other words, the magnetic members 10 A, 10 C, and 10 E absorb heat through magnetocaloric effect while the electric members 10 B, 10 D, and 10 F generate heat through magnetocaloric effect. Therefore, heat transports from the low-temperature side heat exchange unit 40 A to the magnetic member 10 A, from the magnetic member 10 B to the magnetic member 10 C, from the magnetic member 10 D to the magnetic member 10 E, and from the magnetic member 10 F to the high-temperature side heat exchange unit 40 B. Further at this time, the heat conductive members 30 B, 30 D, and 30 F for performing heat conduction within the magnetic body block are not inserted between the magnetic members 10 A and 10 B, between magnetic member 10 C and 10 D, and between the magnetic members 10 E and 10 F.
[0031]As described above, by reciprocating the magnetic circuit provided in correspondence with each magnetic body block 100 A- 100 C in the left-to-right direction in the figure, the magnetic members positioned at both ends of each magnetic body block 100 A to 100 C are alternated with magnetism application and magnetism removal. Further in association with the movement of the magnetic circuit, the heat conductive members 30 A- 30 G are repeated to insert or retreat from the low-temperature side heat exchange unit 40 A, magnetic members 10 A- 10 F, and the high-temperature side heat exchange unit 40 B.
[0032]Thus, the heat gained through magnetocaloric effect transfers from the low-temperature side heat exchange unit 30 A to the high-temperature side heat exchange unit 40 B.
[0033]FIG. 2 is a graph showing the effect of magnetic refrigeration according to the present invention. As shown in this graph, in the initial stage shortly after the magnetic refrigerator has started the operation, the temperature difference between the low-temperature-side heat exchanger 40 A and the high-temperature side heat exchange unit 40 B is small. The temperature difference between the low temperature side heat exchange unit 40 A and the high-temperature side heat exchanger 40 B gradually increases as time elapses, and ultimately, as shown by straight line after long periods, the temperature difference between the low-temperature-side heat exchange unit 40 A and the high-temperature side heat exchange unit 40 B becomes maximum. In this state, by using the heat of the low-temperature side heat exchange unit 40 A, for example, a room temperature can be decreased, while, by using the heat of the high-temperature side heat exchange unit 40 B, the room temperature may be increased, for example.
[0034]Next, when the magnetic circuit provided in correspondence with each magnetic body block as shown in FIG. 1 is allowed to move reciprocally in the left-to-right direction in the figure, the situation in which heat transfers is described based on the schematic diagram of FIGS. 3A-3E .
[0035]As a prerequisite, all the magnetic members forming a magnetic body unit 200 are formed of the same material and the magnetocaloric effect of all the magnetic members are of the same type and it is assumed that, the temperature variation is 5° C. More specifically, it is assumed that all magnetic members have the characteristic according to which temperature rises by 5° C. when applied with magnetism and lowers by 5° C. when magnetic is removed.
[0036]First, as shown in FIG. 3A , the magnetic members are all at 20° C. room temperature in the initial state. Then, as shown in FIG. 3B , by moving the magnetic circuit from this state to the right, magnetism is removed from the magnetic members positioned at one end of each magnetic body block 100 A- 100 C while applying magnetism to the magnetic members positioned on the other end. At the same time, the heat conductive member is inserted so as to enable heat conduction between the adjacent magnetic members of the adjacent magnetic blocks 100 A to 100 C, between the magnetic member positioned on one end of the magnetic body unit 200 and the low-temperature side heat exchange unit 40 A, and between the magnetic member positioned on the other end of the magnetic body unit 200 and the high-temperature side heat exchange unit 40 B.
[0037]In the state of FIG. 3B , the temperature of the magnetic member from which magnetism has been removed lowers to 15° C. while the temperature of the magnetic member to which magnetism is applied rises to 25° C. Therefore, as shown in the figure, the heat is moved to the lower temperature side from the higher temperature side via the heat conductive member.
[0038]Due to the movement of the heat, as shown in FIG. 3C , the temperature of the magnetic member positioned on the one end of the magnetic body unit 200 and the temperature of the low-temperature side heat exchange unit 40 A assume 18° C. while the temperature of the magnetic member positioned on the other end of the magnetic body unit 200 and that of the high-temperature side heat exchange unit 40 B will be 22° C.
[0039]Then, as shown in FIG. 3D , the magnetic circuit is moved in the left from this state and magnetism is removed from the magnetic members positioned on the other end of each magnetic body block 100 A- 100 C, while applying magnetism to the magnetic members positioned on the one end. At the same time, the heat conductive member is inserted to enable heat conduction between the adjacent magnetic members in each magnetic block 100 A- 100 C.
[0040]In the state of FIG. 3D , the temperature of the magnetic member to which magnetism has been applied rises by 5° C. from the temperature in the state of FIG. 3B , while the temperature of the magnetic member from which magnetism has been removed lowers by 5° C. from the state in FIG. 3C . Thus, as shown in figure, heat moves from the high temperature side to the low temperature side within each magnetic body block 100 A- 100 C via the heat conductive member.
[0041]Due to the movement of the heat, as shown in FIG. 3E , the temperature of the low-temperature side heat exchange unit 40 A becomes 18° C., while the temperature of the magnetic member of the magnetic block 100 A becomes 19° C. In addition, the temperature of the magnetic block 100 B becomes 20° C., whereas the temperature of the magnetic member of the magnetic block 100 C becomes 21° C. The temperature of the high-temperature side heat exchange unit 40 B will be 22° C.
[0042]As described above, by reciprocating the magnetic circuit from side to side along the magnetic members while selectively performing the insert/removal operation of the heat conductive member in synchronization with the movement of the magnetic circuit, heat moves from the low-temperature side heat exchange unit 40 A to the high-temperature side heat exchange unit 40 B. As time elapses, the temperature difference between the low-temperature side heat exchange unit 40 A and the high-temperature side heat exchange unit 40 B is gradually increased. Eventually, the temperature difference between the low-temperature side heat exchange unit 40 A and the high-temperature side heat exchange unit 40 B is constant. In this state, it is possible to lower the room temperature by using the heat of the low-temperature side heat exchange unit 40 A while it is possible to utilize the heat of the high-temperature side heat exchange unit 40 B to increase the temperature in the room.
[0043]The description of FIGS. 1A , 1 B and 3 A- 3 E holds true for the case in which a positive magnetic body is used as the magnetic body of the same material and of the same type of the exhibited magnetocaloric effect. When a negative magnetic material is used as the magnetic body of the same material and of the same type of the exhibited magnetocaloric effect, then the direction of heat movement will be opposite from that in FIGS. 3A-3E .
[0044]Therefore, when using the negative magnetic material, the positions of the low-temperature side heat exchange unit 40 A and the high-temperature side heat exchange unit 40 B will be opposite from FIGS. 1A , 1 B and 3 A- 3 E.
[0045]The above description is the principle of magnetic refrigeration to be applied to the present invention. In the description above, a magnetic body block is formed by two magnetic members, and a magnetic body unit is formed by arranging three of the magnetic body blocks. However, the present invention is not limited to these embodiments. That is, the present invention is also applicable to such a case in which, by arranging a more number of magnetic members, a magnetic body block is formed, and by arranging a more number of magnetic blocks, a magnetic body unit is formed.
[0046]Next, the description of the embodiments using the principle described above will be divided into three embodiments. In the magnetic refrigerator pertaining to the first embodiment, the magnetic member, the magnetic circuit and the heat conductive member are arranged annularly and radially, and the magnetic body is fixed with the magnetic circuit and the heat conductive member are rotated. In the magnetic refrigerator pertaining to the second embodiment, respective size of the magnetic member, the magnetic circuit and the heat conductive member are different from the first embodiment form the center of rotation to the outward direction. In the magnetic refrigerator pertaining to the third embodiment, the magnetic circuit and the heat conductive member pertaining to the second embodiment are now fixed and stationary while the magnetic body is rotatable.
[0047]The specific configuration and operation of the magnetic refrigerator according to the first embodiment which utilizes the principle as described above will be described with reference to FIGS. 4 to 8 .
[0048]FIG. 4 is a top view illustrating a schematic configuration of the magnetic refrigerator pertaining to the first embodiment. The figure is illustrated as a perspective view from the top so that the relative positions of the magnetic member, permanent magnet constituting a magnetic circuit and a heat conductive member is understandable. FIGS. 5A to 5C are a top view of the heat exchange unit support plate, a magnetic body arranged plate, and a magnet/heat conductive member arranged plate, respectively, which are constituents of the magnetic refrigerator. FIG. 6 is an exploded cross sectional diagram of the magnetic refrigerator shown in FIG. 4 . FIGS. 7A and 7B together are a schematic diagram explaining the state in which heat transfers when the magnet/heat conductive member arranged plate of the magnetic refrigerator pertaining to the present embodiment is rotated between FIGS. 7A and 7B . FIG. 8 is a diagram explaining the operation of the magnetic refrigerator pertaining to the present embodiment. Note that in FIGS. 7A and 7B , the illustration of the driving unit shown in FIG. 6 is omitted.
[0049]The magnetic refrigerator according to the present embodiment uses the same principle of the magnetic refrigeration shown in FIGS. 1A and 1B . In order to allow for magnetic refrigeration using this principle, the following configuration is provided.
[0050]As shown in FIGS. 4 to 7 , the magnetic refrigerator 500 according to the present embodiment has a circular heat exchange unit support plate 600 (see FIG. 5A ), a hollow disk shaped magnetic body arranged or disposed plate with an opening in the center portion (see FIG. 5B ), and a hollow disk shaped magnet/heat conductive member arranged plate 800 with an opening in the center (see FIG. 5C ). The heat exchange unit support plate has a low-temperature side heat exchange unit 40 A at its central part and a high-temperature heat exchange unit 40 B at its periphery part. The magnet/heat conductive member arranged plate 800 has two disks spaced apart from each other, i.e. an upper side disk 800 A and lower side disk 800 B (see FIG. 6 ). In the magnetic refrigerator 500 , the heat exchange unit support plate 600 , the magnetic body arranged plate 700 , and the magnet/heat conduction unit arranged plate 800 are arranged concentrically (see FIGS. 4 , 6 , and 7 B, in particular). The magnetic body arranged plate 700 is inserted between the upper disc 800 A and lower disc 800 B of the magnet/heat conduction unit arranged plate 800 . The low-temperature side heat exchange unit 40 A is disposed in a hollow space formed by the center part of the magnetic body arranged plate 700 and that of the magnet/heat conduction unit arranged plate 800 . The high-temperature side heat exchange unit 40 B is disposed on the outer periphery of the magnetic body arranged plate 700 and the magnet/heat conduction unit arranged plate 800 (see FIGS. 4 , 6 , and 7 ).
[0051]Note that, since positive magnetic body is disposed on the magnetic body arranged plate 700 in the present embodiment, the heat exchange unit support plate 600 has disposed a low-temperature side heat exchange unit 40 A at its center area while arranging a high-temperature side heat exchange unit 40 B at its outer periphery. When a negative magnetic body is placed on the magnetic body arranged plate 700 , the high-temperature side heat exchange unit 40 B is arranged at the center portion of the heat exchange unit support plate 600 while disposing the low-temperature side heat exchange unit 40 A on its outer periphery. The arrangements of the low-temperature side heat exchange unit 40 A and the high-temperature side heat exchange unit 40 B are different depending on which of the positive and negative magnetic material is to be used.
[0052]As shown in FIG. 5A , a circular low-temperature side heat exchange unit 40 A is erected in the center portion of the heat exchange unit support plate 600 of the magnetic refrigerator 500 and serves to provide a fixed shaft of the magnet/heat conductive member arranged plate 800 . Further, on the outer periphery of the heat exchange unit support plate 600 , a hollow cylindrical, high-temperature side heat exchange unit 40 B is erected along the outer periphery of the heat exchange unit support plate 600 and serves to fix the magnetic body arranged plate 700 .
[0053]As shown in FIG. 5B , the magnetic body arranged plate 700 is a hollow disc with the center portion open, and the opening diameter of the central portion is set slightly larger than the diameter of the low-temperature side heat exchange unit 40 A. Further, the diameter of the magnetic body arranged plate 700 is made up into the same dimension as the inner periphery of the high-temperature side heat exchange unit 40 B of the cylindrical shape. As shown in FIGS. 6 and 7A , 7 B, the magnetic body arranged plate 700 is fixed to the high-temperature side heat exchange unit 40 B through the insulation 525 B. Between the magnetic body arranged plate 700 and the high-temperature side heat exchange unit 40 B, it is preferable to interpose a heat insulating material (not shown) so that the heat does not move between the magnetic body arranged plate 700 and the high-temperature heat exchange unit 40 B.
[0054]A plurality of magnetic members are disposed both in annual and radial directions with a distance from each other on one side of the magnetic body arranged plate 700 (the opposing surface of the disc 800 A) as shown in FIG. 5B . In the present embodiment, on each region of 30° the center angle into which the magnetic body arranged plate 700 is divided, as shown in FIG. 5B , twelve magnetic body units 200 A, 200 B, 200 C . . . 200 G, . . . and 200 L are arranged side by side. Each magnetic body unit 200 A, 200 B, 200 C . . . 200 G, . . . and 200 L has six magnetic members disposed toward the outer periphery from the center of the magnetic body arranged plate 700 . For example, the magnetic body unit 200 A has the magnetic member 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, and 10 Af disposed and the magnetic body unit 200 B has the magnetic member 10 Ba, 10 Bb, 10 Bc, 10 Bd, 10 Be, the 10 Bf arranged, respectively. In each magnetic body unit, two magnetic members form a group to represent a magnetic body block. For example, in the magnetic body unit 200 , the magnetic members 10 Aa and 10 Ab o constitute the magnetic body block 100 Aa, the magnetic members 10 Ac and 10 Ad constitute the magnetic body block 100 Ab, and the magnetic members 10 Ae and 10 Af constitute the magnetic body block 100 Ac, respectively. Further, in the magnetic body unit 200 B, the magnetic members 10 Ba and 10 Bb constitute a magnetic body block 100 Ba, the magnetic members 10 Bc, 10 Bd constitute a magnetic body block 100 Bb, and the magnetic members 10 Be, 10 Bf constitute a magnetic body block 100 Bc.
[0055]Thus, on the magnetic body arranged plate 700 in the present embodiment, each magnetic body unit 200 A, 200 B, 200 C, . . . , 200 G, . . . and 200 L is formed by three magnetic body blocks 100 Aa- 100 Ab- 100 Ac, 100 Ba- 100 Bb- 100 Bc. Further, each magnetic body block 100 Aa, 100 Ab, 100 Ac, 100 Ba, 100 Bb, 100 Bc, . . . is formed by two magnetic members 10 Aa- 10 Ab, 10 Ac- 10 Ad, 10 Ae- 10 Af, 10 Ba- 10 Bb, 10 Bc- 10 Bd, and 10 Be- 10 Bf . . . . When focusing on the single magnetic body unit 200 A of the magnetic body arranged plate 700 in the present embodiment, the magnetic body unit 200 A is made up of six magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, and 10 Af. These magnetic members form three magnetic body blocks 100 Aa, 100 Ab, and 100 Ac. Thus, these magnetic body blocks are formed of two magnetic members 10 Aa- 10 Ab, 10 Ac- 10 Ac, 10 Ae- 10 Af. The magnetic body units 200 B to 200 L are formed similarly with the magnetic body unit 200 A. Therefore, the magnetic body arranged plate 700 in the present embodiment represents a configuration equivalent to that shown in FIG. 1A where the magnetic body units 200 are arranged in twelve rows parallel to each other.
[0056]The magnetic member 10 Aa to be used in the present embodiment may be formed directly on the magnetic body arranged plate 700 , but in order to be able to effectively utilize the magnetocaloric effect, the magnetic body arranged plate 700 is preferably composed of a material of large thermal resistance. With small thermal resistance, the heat generated by the magnetic members 10 Aa and others would be dissipated through the magnetic body arranged plate 700 . In addition, in order to increase the thermal resistance, the magnetic member 10 Aa and the other are not formed on the magnetic body arranged plate 700 directly. Rather, a thermal insulating film or heat insulating layer may be interposed between the magnetic member 10 Aa etc. and the magnetic body arranged plate 700 .
[0057]Further, the magnetic member 10 Aa, . . . may be formed integrally as a magnetic body unit on the magnetic body arranged plate 700 via the heat insulating film or heat insulating layer. Further, each magnetic body block 100 A is prepared separately via the heat insulating film or heat insulating layer, and then multiple of these magnetic body blocks may be disposed on the magnetic body arranged plate 700 .
[0058]In the present embodiment, the magnetic member 10 Aa etc. are formed of the same material, and a positive magnetic material is used for the material. The positive magnetic material is manufactured using a material by which a paramagnetic stat and a ferromagnetic state occur reversibly where the paramagnetic state (the magnetic spin state of the disorder) occurs without magnetism being applied whereas, when applied by magnetism, a ferromagnetic state (state in which the magnetic spins are aligned in one direction) is exhibited.
[0059]The material of the positive magnetic material may be made from Gd or an alloy based on, such as Gd—Y system, Gd—Dy-based, Gd—Er system, Gd—Ho system, La La (Fe, Si) 13 , La(Fe, Al) 13 and other magnetic material.
[0060]Although not used in this embodiment, it is also possible to use a negative magnetic material for the same material as the magnetic member 10 Aa. The negative magnetic material transfers into different state of order depending on whether magnetism is being applied or not. Further, the negative magnetic material presents a state with high degree of order when magnetism is not being applied compared to the case where magnetism is being applied. As the negative magnetic material, such a material in used in which two states of order, i.e. an order transfer occurs in response to application/removal of magnetism. Further, the negative magnetic material takes antiferromagnetic state (state where adjacent spins aligned facing opposite directions) without magnetism being applied and undergoes a ferromagnetic state (state where adjacent spins are all pointed to one direction). The negative magnetic material may be manufactured by using a material by which a ferromagnetic state and an antiferromagnetic state occur reversibly when the magnetic moment of the material itself is changed greatly. As the negative magnetic material, it is possible to use a magnetic material such as FeRh alloy, CoMnSiGe system, or NiMnSn system.
[0061]Generally, the positive magnetic material and the negative magnetic material differ by nature from each other. Thus the magnitude in the temperature change due to magnetocaloric effect with respect to the positive magnetic material and the negative magnetic material are different due to the difference in the direction of heat generation/absorption. Therefore, as in the present embodiment, when using one of the positive and negative magnetic material, the temperature changes for all the magnetic members due to magnetocaloric effect will be the same. Therefore, a stable heat conduction characteristic as an overall magnetic refrigerator is obtained with improvement in the heat transport efficiency. Further, compared to the positive magnetic material, since the magnetocaloric effect of the negative magnetic material is smaller, considering the heat transfer efficiency, it is preferable to structure the magnetic body arranged plate 700 using a positive magnetic material. Moreover, since the negative magnetic material is rare compared to the positive magnetic material, it is also preferable to use the positive magnetic material for constituting the magnetic body arranged plate 700 in terms of the costs.
[0062]In the present embodiment, as shown in FIG. 4 , FIG. 5B , and FIG. 8 , the magnetic member 10 Aa, etc. is shaped obtainable as if a fan would be cut in the radial direction with a constant width. However, other shapes may be employed such as spherical, ellipsoidal, cubic, cylindrical, or elliptical cylindrical shape.
[0063]As described above, the magnetic body arranged plate 700 has a magnetic body unit 200 A which has a plurality of magnetic members 10 Aa etc. arranged in row spaced to each other. The magnetic body arranged plate 700 has a plurality of the magnetic body units 200 A arranged annually side by side with a space there between in the circumferential direction which crosses the arrangement direction of the magnetic members 10 Aa etc.
[0064]The magnetic body unit 200 A has a magnetic body block on which a plurality of the magnetic members 10 A etc. are disposed in row with a space or gap. A plurality of the magnetic body blocks 100 Aa etc. are arranged in row along the arrangement direction of the magnetic members 10 Aa etc. with spacing to form the magnetic body unit 200 A.
[0065]Since the magnetic body arranged plate 700 is configured above, the low-temperature side heat exchange unit 40 A is located adjacent to the magnetic members 10 Aa, 10 Bb and etc. with a space positioned on one end of the magnetic body units 200 A, 200 B, 200 C through 200 G to 200 L formed on the magnetic body arranged plate 700 . Also, the high-temperature side heat exchange unit 40 B is located adjacent to the magnetic members 10 Af, 10 Bf, etc. positioned on the other end of the magnetic body units 200 A, 200 B, 200 C through 200 G . . . to 200 L formed on the magnetic body arranged plate 700 .
[0066]As shown in FIG. 5C , the magnet/heat conduction unit arranged plate 800 is a hollow disc with the center portion open, and the opening diameter of the central portion is set slightly larger than the diameter of cylindrical low-temperature side heat exchange unit 40 A of the heat exchange unit support plate 600 . Further, the diameter of the magnet/heat conduction unit arranged plate 800 is set slightly smaller than the size of the inner periphery of the cylindrical high-temperature side heat exchange unit 40 B of the heat exchange unit support plate 600 . This configuration is intended to ensure the magnet/heat conduction unit arranged plate 800 is allowed to rotate between the low-temperature heat exchange unit 40 A and the high-temperature heat exchange unit 40 B. The magnet/heat conduction unit arranged plate 800 is composed of two, i.e. upper and lower discs 800 A, 800 B, which are connected magnetically with a gap interposed.
[0067]Note that, between the lower-side heat exchange unit 40 A and the upper disc 800 A, and between the lower-temperature side heat exchange unit 40 A and the upper disc 800 A, and between the lower-temperature side heat exchange unit 40 A and the lower disc 800 B, insulating material 525 A is interposed to block heat transfer between the low-temperature side heat exchange unit 40 A, the upper disc 800 A, the lower disc 800 B. Further, it is preferable for the bearings 520 Ab and 520 Bb to insulating property to block the heat transfer among the high-temperature side heat exchange unit 40 B, the upper disc 800 A, and the lower disc 800 B. For this purpose, for example, the bearings 520 Ab and 520 Bb themselves may be made of thermal insulation material. Alternatively, the bearings 520 Ab and 520 Bb may have a heat insulating film coated on the surfaces.
[0068]The two discs, i.e. the upper side and lower side discs 800 A, 800 B are configured to be separately rotatable about the low-temperature side heat exchange unit 40 A and supported by a bearing provided at the low-temperature side heat exchange unit 40 A or by a bearing provided on the outer periphery of the upper and lower discs 800 A, 800 B, respectively. As shown in FIG. 6 , the upper disc 800 A is rotatably supported by the bearings 520 Aa, 520 Ab, while the lower disc 800 B is rotatably supported by the bearings 520 Ba, 520 Bb. Therefore, the upper disc 800 A may rotate separately from the lower disc 800 B. Reference numbers 560 A, 560 B constitute a driving unit.
[0069]When the servo motor 540 A is rotated, the ring gear 560 A meshed with the gear 550 A rotates on its axis to rotate the upper disc 800 A. Further, when the servo motor 540 B is rotated, the ring gear 560 B meshed with the gear 550 B rotates about its axis to rotate the lower disc 800 B. In addition, when the upper and lower discs are rotated in synchronization, the two, i.e. the upper and lower discs 800 A, 800 B rotate integrally.
[0070]In the present embodiment, the servo motors 540 A and 540 B are rotated in synchronization. Therefore, the magnet/heat conduction unit arranged plate 800 is rotated about the low-temperature side heat exchange unit 40 A between the low-temperature side heat exchange unit 40 A and the high temperature side heat exchange unit 40 B by sandwiching the magnetic body arranged plate 700 by the upper and lower discs 800 A, 800 B.
[0071]On one side of the upper disc 800 A constituting the magnet/heat conduction unit arranged plate 800 (under side of the disc 800 A shown in FIGS. 6 and 7A , 7 B), as shown in FIG. 5C , a plurality of permanent magnets and the plurality of heat conductive members are arranged. One permanent magnet is arranged to face each of the magnetic body blocks 100 Aa, 100 Ab, 100 Ac, 100 Ba, 100 Bb, and 100 Bc of the magnetic body unit 200 A, 200 B, 200 C through 200 G to 200 L. Each time the permanent magnet moves over to the adjacent magnetic body unit in accordance with the rotation of the magnet/heat conduction unit arranged plate 800 by 30° C., the permanent magnet performs a reciprocal movement in a radial direction within the magnetic body block 100 Aa, 100 Ab, 100 Ac, 100 Ba, 100 Bb, and 100 Bc, etc. of the adjacent magnetic body unit 200 A, 200 B, 200 C through 200 G to 200 L. Therefore, the permanent magnet applies magnetism separately to the magnetic member of the magnetic body unit 200 A, 200 B, 200 C through 200 G to 200 L.
[0072]For example, as shown in FIG. 4 , FIG. 5B , FIG. 5C and FIG. 7A , on the upper disc 800 A of the magnet/heat conductive member arranged plate 800 , the permanent magnets 20 Aa, 20 Ac, and 20 Ae present in the corresponding position of the magnetic body unit 200 A are respectively disposed to oppose the magnetic member 10 Aa, 10 Ac, and 10 Ae of magnetic body unit 200 A of the magnet body arranged plate 700 . Further, the permanent magnets 20 Ba, 20 Bc, and 20 Be disposed in the corresponding position of the magnetic body unit 200 B are respectively disposed to oppose the magnetic members 10 Bb, 10 Bd, and 10 Bf. In this state, when the magnet/heat conductive member arranged plate 800 rotates by 30° in a clockwise direction, the permanent magnets 20 Aa, 20 Ac, and 20 Ae disposed in the corresponding position of the magnetic body unit 200 A are brought to the positions respectively corresponding to the magnetic members 10 Ba, 10 Bc, and 10 Be of the magnetic body unit 200 B. Further, the permanent magnets present in the corresponding position of the magnetic body will be brought to positions to oppose the magnetic members 10 Ab, 10 Ad, and 10 Af, respectively. In other words, each time the magnet/heat conductive member arranged plate 800 rotates by 30° clockwise, in each of the magnetic body units 200 A, 200 B, 200 C through 200 G to 200 L, the permanent magnet moves reciprocally in each magnetic body block. The positional relationship between this permanent magnet and the magnetic body represents the same the situation in which, each time the magnet/heat conductive member arranged plate 800 rotates 30 degrees, the positional relationship is repeatedly alternated between FIG. 1A and FIG. 1B .
[0073]Therefore, when moving the magnet/heat conductive member arranged plate 800 in the arrangement direction of the magnetic body units 200 , 200 B, 200 C through 200 G to 200 L, the positional relationship between the permanent magnet and the magnetic body transfers as follows.
[0074]First, as shown in FIG. 4 and FIG. 7A , the permanent magnets 20 Aa, 20 Ac, and 20 Ae apply magnetism to the magnetic members 10 Aa, 10 Ac, and 10 Ae at the same time positioned on one end of each magnetic body block 100 Aa, 100 Ab, 100 Ac of one of the adjacent magnetic body unit, 200 A. Further, as shown in FIG. 4 and FIG. 7B , the permanent magnets 20 Ba, 20 Bc, and 20 Be apply magnetism to the magnetic members 10 Bb, 10 Bd, and 10 Bf at the same time positioned on the other end of the adjacent magnetic body unit, 200 B. With respect to the other magnetic body units 200 C to 200 L, the positional relationship between the permanent magnet and the magnetic member between two adjacent magnetic body units is the same as the case of magnetic body units 200 A and 200 B. The positional relationship between the permanent magnet and the magnetic body or member described above between two adjacent magnetic units is referred to as State 1 .
[0075]Next, when the magnet/heat conductive member arranged plate 800 is rotated 30° clockwise, the permanent magnets 20 Aa, 20 Ac, and 20 Ae simultaneously apply magnetism to the magnetic members 10 Ba, 10 Bc, and 10 Be positioned on the one end of each magnetic body block 100 Ba, 100 Bb, and 100 Bc of the other one of the adjacent magnetic body units, 200 B. This state is the same as the situation in which the permanent magnets 20 Ba, 20 Bc, and 20 Be shown in FIG. 7B move to the magnetic members 10 Ba, 10 Bc, and 10 Be on the left side. On the other hand, the permanent magnets present in the corresponding position of the magnetic body unit 200 L apply magnetism simultaneously to the magnetic members 10 Ab, 10 Ad, and 10 Af positioned on the other end of each magnetic body block 100 Aa, 100 Ab, and 100 Ac of the one of the adjacent magnetic body units, 200 L. This state is the same as the situation in which the permanent magnets 20 Aa, 20 Ac, and 20 Ae shown in FIG. 7A move to the magnetic members 10 Ab, 10 Ad, and 10 Ae on the right side. With respect to the other magnetic body units 200 C to 200 L, the positional relationship of the permanent magnet and the magnetic body between adjacent magnetic body units transition in the same manner as in the case of the magnetic body units 200 A, 200 B. The positional relationship of the permanent magnet and the magnetic body between adjacent magnetic body units is referred to as State 2 .
[0076]Thus, each time the magnet/heat conductive member arranged plate 800 is rotated 30°, in all the he magnetic body units 200 A 1 , 200 B, 200 C through 200 G to 200 L, the state 1 and the state 2 are repeated. In other words, in all the magnetic body units, 200 A, 200 B, 200 C, . . . , 200 G, . . . , and 200 L, the state in FIG. 1A and the state in FIG. 1B are repeated.
[0077]On one side of the lower disc 800 B forming the magnet/heat conductive member arranged plate 800 (on the upper side of the disc 800 B shown in FIGS. 6 , 7 A), magnetic projections are formed. The magnetic projection is arranged so as to correspond to the arrangement of the permanent magnet disposed on one side of the upper disc 800 A. For example, as shown in FIGS. 6 , 7 A, the magnetic projection 20 Ab is provided to correspond to the permanent magnet 20 Aa, the magnetic projection 20 Ad to correspond the permanent magnet 20 Ac, the magnetic projection 20 Af to correspond the permanent magnet 20 Ae, respectively. Further, the magnetic projection 20 B is arranged to correspond to the permanent magnet 20 Ba, the magnetic projection 20 Bd to correspond to the permanent magnet 20 Bc, and the magnetic projection 20 Bf to correspond to the permanent magnet 20 Be, respectively. By receiving the magnetic force lines from each permanent magnet, it is intended that the magnetic resistance between the permanent magnet and the magnetic projection is kept minimized and the magnetic force lines from the permanent magnet will pass through the magnetic body without leak.
[0078]The magnet/heat conductive member arranged plate 800 is composed of two, magnetically connected flat plates that sandwich the magnetic body arranged plate 700 . The permanent magnet disposed on the upper disk 800 A and the magnetic projection disposed on the lower disc 800 B forms a magnetic circuit between the upper disc 800 A and lower disc 800 B. This magnetic circuit constitutes a magnetism applying unit. In the present embodiment, a permanent magnet is used for the mechanism to generate magnetism. However, in place of the permanent magnet, it is also possible to use electromagnets or superconducting magnets. When configured by an electromagnet to form a magnetic circuit, it is possible to change the range of the magnitude of the magnetic applied to the magnetic body. It is possible to impart the versatility to the magnetic applying unit. However, from the point of view of the utility and energy conservation, the use of permanent magnet is desirable.
[0079]In the present embodiment, a permanent magnet is arranged on the upper disc 800 A while a magnetic projection is disposed in the lower disc 800 B. It is also possible to have the opposite structure from this. The magnetic projection may be arranged on the upper disc 800 A while the permanent magnet may be placed on the lower disc 800 B. Further, in the present embodiment, both discs are jointly rotated as unity. However, if magnetically connected, the two discs may be arranged separately. Since the upper disk 800 A and the lower disc 800 B are magnetically connected and the permanent magnet is provided to face the magnetic projection, the magnetic flux from the permanent magnet may be utilized efficiently and the miniaturization of the permanent magnet and weight reduction are possible.
[0080]All the permanent magnets provided on the magnet/heat conductive member arranged plate 800 are provided with a heat conductive member on the outer periphery of each permanent magnet, as shown in FIGS. 4 , 5 C, 6 and 7 A, 7 B. The heat conductive member conducts or transfers the heat generated in each magnetic body unit from the low-temperature side heat exchange unit to the high-temperature side heat exchange unit. The heat condition material is selectively inserted or removed between magnetic members, in the direction of rotation of the magnet/heat conductive member arranged plate 800 . When the heat conductive member is inserted between magnetic members, heat is conducted between the magnetic members. When the heat conductive member is inserted between the magnetic member and the low-temperature side heat exchange unit, heat conduction takes place between the magnetic member and the low-temperature side heat exchange unit. Moreover, when the heat conduction is conducted between the magnetic body and high-temperature side heat exchange unit, heat transfers between the magnetic member and the high-temperature side heat exchange unit.
[0081]As shown in FIG. 5C , the heat conductive members are provided on one side of the upper disc 800 A forming the magnet/heat conductive member arranged plate 800 (lower side of the disc 800 A shown in FIGS. 6 , 7 A and 7 B) at four or three locations on each magnetic body unit 200 A, 200 B, 200 C through 200 G to 200 L. As shown in FIG. 5C , at the corresponding positions of the magnetic body unit 200 A, three heat conductive members 30 Ab, 30 Ad, and 30 Af are provided on the side of outer periphery of the permanent magnet 20 Aa, 20 Ac, and 20 Ae. In the corresponding position on the magnetic body unit 200 B, four heat conductive members 30 Ba, 30 Bc, 30 Be and 30 Bg are provided. The heat conductive members 30 Bc, 30 Be, 30 Bg are provided on the outer periphery of the permanent magnet 20 Ba, 20 Bc and 20 Be.
[0082]All the heat conductive members 30 Ab, 30 Ad, 30 Af, 30 Ba, 30 Bc, 30 Be, 30 Bg, etc. is made of solid high heat conduction material that facilitates heat conduction. As high heat conduction materials, Cu or Al is desirable.
[0083]The thickness of the heat conductive member in a radial direction is set to such a size such that the heat conductive member can be tightly received in or be slightly larger than the gap between the magnetic members, that between the magnetic member and the low-temperature side heat exchange unit 40 A, or that between the magnetic member and the high-temperature side heat exchange unit 40 B. For example, the radial thickness of the heat conductive member 30 Ab, 30 Ad, 30 Af, 30 Ba, 30 Bc, 30 Be, 30 Bg etc. is determined such that these can be inserted respectively between the magnetic members, 10 Aa- 10 Ab, 10 Ac- 10 Ad, 10 Ae- 10 Af, the low-temperature side heat exchange unit 40 A-magnetic member 10 Ba, magnetic member 10 Bb- 10 Bc, 10 Bd- 10 Be, the magnetic member 10 Bf-high temperature side heat exchange unit 40 B while ensuring heat conduction between these. Further, the shape of the heat conductive member 30 Ab, 30 Ad, 30 Af, 30 Ba, 30 Bc, 30 Be, 30 Bg etc. may be preferably shaped to match the respective shape of the gap between the magnetic members, 10 Aa- 10 Ab, 10 Ac- 10 Ad, 10 Ae- 10 Af, the low-temperature side heat exchange unit 40 A-magnetic member 10 Ba, magnetic member 10 Bb- 10 Bc, 10 Bd- 10 Be, the magnetic member 10 Bf—the high temperature side heat exchange unit 40 B.
[0084]The portion of the heat conductive member 30 Ab and etc. on which the magnetic member 10 Aa etc., the low-temperature side heat exchange unit 40 A, and the high-temperature heat exchange unit 40 B are in contact, may be formed in a coating layer with high heat conductivity and high anti-wearness. For example, by applying carbon nanotubes on the surface of the heat conductive member 30 Ab etc., both the wear resistance and heat conductivity are preferably improved. Further, the heat conductive member 30 Ba to be inserted between the magnetic member 10 Ba and the low-temperature side heat exchange unit 40 A as well as the heat conductive member 30 Bg to be inserted between the magnetic member 10 Bf and the high-temperature side heat exchange unit 40 B may be different in material or structure from the heat conductive members 30 Bc, 30 Be which cause heat conduction to the magnetic members 10 Ba- 10 Bf.
[0085]Note that the magnet/heat conductive member arranged plate 800 is preferably made from the material of low thermal conductivity with high heat resistance in order to prevent the heat generated by the magnetic body 10 Aa etc. and the heat conducted through the heat conductive member 30 Aa from being escaped.
[0086]When the magnet/heat conductive member arranged plate 800 having the above configuration is rotated with respect to the magnetic body arranged plate 700 , the heat conductive member 30 Ab, . . . transfers heat in the following manner.
[0087]First, when the positional relationship of the permanent magnet and the magnetic body is found in the state 1 shown in FIGS. 4 and 8 , in the corresponding position of the magnetic body unit 200 A, the positional relationship between the heat conducting member and the magnetic body may be illustrated as in FIG. 7A .
[0088]In the state 1, as shown in FIG. 7A , the permanent magnet 20 Aa is positioned to the magnetic member 10 Aa, the permanent magnet 20 Ac to the magnetic member 10 Ac, and the permanent magnet 20 Ae to the magnetic member 10 Ae, respectively. At this time, the magnetic members 10 Aa, 10 Ac, and 10 Ae are applied with magnetism while the magnetic members 10 Ab, 10 Ad, and 10 Af are free from magnetism and not magnetized. At this time, the magnetic members 10 Aa, 10 Ac, and 10 Ae generate heat. At the same time, the heat conductive member 30 Ab is inserted between the magnetic members 10 Aa and 10 Ab, the heat conductive member 30 Ad between the magnetic member 10 Ac and 10 Ad, the heat conductive member 30 Af between the magnetic members 10 Ae and 10 Af, respectively. Thus, heat conduction is performed between the adjacent magnetic members within each magnetic body block. In other words, the heat generated by the magnetic members 10 Ab, 10 Ad, and 10 Af through magnetocaloric effect is transferred to the magnetic members 10 Ab, 10 Ad, and 10 Af, respectively. In addition, in this state, there is no heat conduction between the low-temperature side heat exchange unit 40 A and the magnetic member 10 Aa and between the high-temperature side heat exchange unit 40 B and the magnetic unit 10 Af. Also, no heat conduction is made between the magnetic body blocks.
[0089]Further, in the corresponding position of the magnetic body unit 200 B, the positional relationship between the heat conducting member and the magnetic body is such as shown in FIG. 7B .
[0090]As shown in FIG. 7B , the permanent magnet 20 B is positioned to the magnetic member 10 Bb, the permanent magnet 20 Bc to the magnetic member 10 Bd, and the permanent magnet 20 Be to the magnetic member 10 Af, respectively. In this instance, the magnetic members 10 Bb, 10 Bd, and 10 Bf are applied with magnetism while the magnetic members 10 Ba, 10 Bc, and 10 Be are not applied with magnetism but the magnetism is removed from. At this time, the magnetic members 10 Bb, 10 Bd, and 10 Bf generate heat. At the same time, the heat conductive member 30 Ba is inserted between the low-temperature side heat exchange unit 40 A and the magnetic member 10 Ba, the heat conductive member 30 Bc between the magnetic members 10 Bb and 10 Be, the heat conductive member Be between the magnetic members 10 Bd and 10 Be, the heat conductive member 30 Bg between the magnetic member 10 Bf and the high-temperature side heat exchange unit 40 B, respectively. Thus heat conduction takes place between the adjacent magnetic members, 10 Bb- 10 Bc, 10 Bd- 10 Be between the adjacent magnetic body blocks 100 Ba, 100 Bb, and 100 Bd. Also, heat conduction occurs between the magnetic member 10 Ba positioned on one end of the magnetic body unit 200 B and the low-temperature side heat exchange unit 40 A as well as between the magnetic member 10 Bf and the high-temperature side heat exchange unit 40 B. In other words, the magnetic members 10 Ba, 10 Bd, and 10 Bd absorb heat through magnetocaloric effect while the magnetic members 10 Bb, 10 Bd, and 10 Bf generate heat through magnetocaloric effect. Therefore, heat transfers from the low-temperature side heat exchange unit 40 A to the magnetic member 10 Ba, from the magnetic member 10 Bb to the magnetic member 10 Bc, from the magnetic member 10 Bd to the magnetic member 10 Be, and from the magnetic member 10 Bf to the high-temperature heat exchange unit 40 B.
[0091]As described above, a plurality of magnetic applying unit arranged on the magnet/heat conductive member arranged plate 800 exhibit magnetocaloric effect by selectively approaching or departing from a plurality of magnetic bodies disposed on the magnetic body arranged plate 700 in response to a relative movement between the magnet/heat conductive member arranged plate 800 and magnetic body arranged plate 700 . Further, a plurality of the heat conductive members disposed on the magnet/heat conductive member arranged plate are configured to selectively insert or remove from between the magnetic members disposed in the magnetic body arranged plate 700 , between the low-temperature side heat exchange unit 40 A and the magnetic member, and between the high-temperature side heat exchange unit 40 B and the magnetic member to conduct the heat generated by magnetocaloric effect in response to the relative movement between the magnet/heat conductive member arranged plate 800 and the magnetic body arranged plate 700 .
[0092]The state 1 described above is shown in FIG. 8 . In the corresponding position of the magnetic body unit 200 A, heat is transferred between the adjacent magnetic members within each magnetic body block, while in the corresponding position of the magnetic body unit 200 B, heat is conducted between the adjacent magnetic members of the adjacent magnetic body blocks, between the magnetic member positioned on one end of the magnetic body unit 200 B and the low-temperature heat exchange unit 40 A, and between the magnetic member positioned on the other end of magnetic body unit 200 B and the high-temperature side heat exchange unit 40 B.
[0093]When the positional relationship between the permanent magnet and the magnetic body is found in the state 1 shown in FIG. 8 , in the corresponding position of the magnetic body unit 200 A, the positional relationship between the heat conductive member and the magnetic body is equivalent to that shown in FIG. 7A . At the same time, in the corresponding position of the magnetic body unit 200 B, the positional relationship between the heat conductive member and the magnetic body is equivalent to that shown in FIG. 7B .
[0094]Now after rotating the magnet/heat conductive member arranged plate 800 by 30° clockwise to bring the positional relationship between the permanent magnet and the magnetic body in the state 2 shown in FIG. 8 , in the corresponding position of the magnetic body unit 200 A, the positional relationship between the heat conductive member and the magnetic body is equivalent to that shown in FIG. 7B . At the same time, in the corresponding position of the magnetic body unit 200 B, the positional relationship between the heat conductive member and the magnetic member is equivalent to that shown in FIG. 7A . The positional relationship between the permanent magnet and the magnetic body is opposite from the positional relationship between the permanent magnet and the magnetic body with respect to between the adjacent magnetic body units.
[0095]The state 2 described above is shown in FIG. 8 . In the corresponding position of the magnetic body unit 200 A, heat is conducted between the adjacent magnetic members between the adjacent magnetic body blocks, between the magnetic member positioned on one end of the magnetic body unit 200 A and the low-temperature side heat exchange unit, and between the magnetic member positioned on the other end of the magnetic body unit 200 A and the high-temperature side heat exchange unit 40 B. In the corresponding position of the magnetic body unit 200 B, heat is conducted between the adjacent magnetic members in each magnetic body block.
[0096]As described above, in the state 1, the heat conductive member of the magnet/heat conductive member disposed or arranged plate 800 provides thermal transfer between adjacent magnetic members within each magnetic body block of one of adjacent magnetic body units while also providing thermal transfer between adjacent magnetic members of the adjacent magnetic blocks of the other of the adjacent body units, between the magnetic member positioned at one end of the other magnetic body units and the low-temperature side heat exchange unit and between the magnetic member at the other end of the other magnetic body unit and the high-temperature side heat exchange unit. Further, in the state 2, heat conduction takes place between the adjacent magnetic members within each magnetic body block of the other adjacent magnetic body units while the heat conduction occurs between the adjacent magnetic members of the adjacent magnetic blocks of the one adjacent magnetic body unit, between the magnetic member at one end of the one magnetic body unit and the low-temperature side heat exchange unit, and between the magnetic member at the other end of the one adjacent magnetic body unit.
[0097]The driving unit shown in FIGS. 6 and 7A , 7 B is intended to drive the magnetic body arranged plate 700 or the magnet/heat conductive member arranged plate 800 to move the magnetic body arranged plate 700 and the magnet/heat conductive member arranged plate 800 relatively. As long as the magnetic body arranged plate or the magnet/heat conductive member arranged plate 800 can be rotated, any types of the electric motor may be employed. In the present embodiment, the magnet/heat conductive member plate 800 is caused to rotate about its center as rotation axis.
[0098]The low-temperature side heat exchange unit 40 A and the high-temperature side heat exchange unit 40 B are provided with mechanism to perform heat exchange with an external environment such as room or indoor air. For example, such a mechanism may be adopted in which heat exchange with external environments takes place by supplying refrigerant from external.
[0099]The magnetic refrigerator pertaining to the present embodiment configured above works in the following manner as a magnetic refrigerator.
[0100]First, by operating the driving unit to rotate the magnet/heat conductive member arranged plate 800 clockwise or counter-clockwise, at each rotation of 30°, the states in FIGS. 1A , 1 B, i.e. the states of FIGS. 7A and 7B are repeated alternately. That is, the state 1 and the state 2 are repeated. Through this repetition, in each magnetic body unit, heat transfers from the low-temperature side heat exchange unit 40 A to the high-temperature side heat exchange unit 40 B. Eventually, as in the graph shown in FIG. 2 , the temperature of the low-temperature side heat exchange unit 40 A is lowered while the temperature of the high-temperature heat exchange unit 40 B may be raised to create a temperature difference between the low-temperature side heat exchange unit 40 A and the high-temperature side heat exchange unit 40 B. Note that the principle according to which the temperature difference between the low-temperature side heat exchange unit 40 A and the high-temperature side heat exchange unit 40 B will be expanded is the same as the principle explained with reference to FIGS. 3A-3E .
[0101]When configuring a magnetic refrigerator of large cooling capacity, the number of the magnetic blocks arranged in series is increased to connect to both the low-temperature side heat exchange unit 40 A and the high-temperature side heat exchange unit 40 B. By increasing the number of serially connected magnetic body blocks, it is possible to increase further the temperature difference between the high-temperature side heat exchanger 40 B and the low-temperature-side heat exchanger 40 A.
[0102]The magnetic refrigerator of the present embodiment can be applied to an air conditioner performing air conditioning, a refrigerator, a vehicle air conditioner that performs air conditioning of a passenger compartment, and refrigeration system of the vehicle, etc.
[0103]In the present embodiment, such a configuration is illustrated in which a permanent magnet, heat conductive member and the magnetic projection are formed on a magnet/heat conductive arranged plate 800 . When the permanent magnet, heat conductive member and the magnetic projection are formed integrally, the size of the magnet/heat conductive member arranged plate 800 may be miniaturized and made light-weighted.
[0104]Further, in the present embodiment, both the magnetic body arranged plate 700 and the magnet/heat conductive member arranged plate 800 are formed in circular shape and rotated relative to each other. The magnetic body arranged plate 700 and the magnet/heat conductive member arranged plate 800 may be formed flat for a linear reciprocal movement relative to each other.
[0105]When the magnetic refrigerator is configures as described above, simply by relatively moving the magnetic body arranged plate 700 against the magnet/heat conductive member arranged plate 800 in the arrangement direction of the magnetic body units, magnetic refrigeration is available so that the configuration of the magnetic refrigerator is simplified and miniaturization, light-weightiness, and low cost may be achieved.
[0106]Next, the specific configuration of the magnetic refrigerator according to the second embodiment will be described with reference to FIGS. 5A-5C and FIGS. 9A and 9B . In the magnetic refrigerator pertaining to the second embodiment, the sizes or dimensions of the magnetic body, the magnetic circuit and the heat conductive member are varied toward outside from the center so that the heat transfer characteristic may be made appropriate.
[0107]In the present embodiment, as shown in FIG. 5B and FIG. 9A , the magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, 10 Af for forming a magnetic unit 200 A in the magnetic body arranged plate 700 , have the same volume, respectively. This is intended to ensure the same heat capacity of the adjacent magnetic members in the radial direction toward the outer periphery from the inner periphery of the magnetic body arranged plate 700 . As shown in FIG. 5B , the magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, 10 Af have the shape as cut by a constant width in the radial direction of the fan. In this shape, when the same thickness in the radial direction of all the magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, the 10 Af, the volume of the magnetic members are different. For this reason, the amount of heat obtained by magnetocaloric effect is different, thus it is not possible to conduct heat evenly magnetic material between adjacent. Therefore, the efficiency of the heat transport is reduced. For example, if the heat capacity of the magnetic member of one of the adjacent members is larger than the heat capacity of the magnetic member of the other, heat is not fully passed to the small magnetic member from the magnetic member with larger heat capacity. In the reversed case of this situation, heat can be successfully conveyed from the small capacity magnetic member to the larger magnetic member. However, because of the difference in heat capacity, the temperature change at the member that has received heat is not sufficient. Therefore, the situation in which heat transfer can be performed most efficiently is the situation in which the heat capacity of the magnetic members is the same and thus the volume thereof the same. In the present embodiment, since the same volume is used for all the magnetic members, the heat transfer efficiency of the magnetic refrigerator is improved, and heat transfer efficiency and the heat transport capability of the magnetic refrigerator will be improved.
[0108]Under such circumstances, in the present embodiment, as shown in FIG. 9A , the radial thickness of respective magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, the 10 Af are respectively defined as LM1, LM2, LM3, LM4, LM5, LM6 and are configured to meet the following formula: LM1>LM2>LM3>LM4>LM5>LM6.
[0109]And yet, the thickness of these members is dimensioned in such a way that the heat capacity of all the magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, and 10 Af is the same. Since the magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, and 10 Af are shaped by cutting a fan radially, the length along the periphery will be greater from inner periphery toward the outer periphery. To ensure the same volume, the thickness is set thinner from the center.
[0110]The same holds true on the magnetic body units 200 B, 200 C through 200 G to 200 L. Greater is the same in 200 L, the magnetic unit 200 B, 200 C, . . . , 200 G, . . . shown in FIG. 5B .
[0111]As shown in FIG. 9A , the radial thickness of the permanent magnets 20 Aa, 20 Ac, and 20 Ae that are disposed on a disc 800 A at the upper side of the magnet/heat conductive member disposed plate 800 is thinner from the inner circumference toward the outer circumference of the circular plate 800 A, and is adjusted to the radial thickness of the magnetic members 10 Aa, 10 Ac, and 10 Ae. The radial thickness of the magnetic projections 20 Ab, 20 Ad, 20 Af which are disposed in a lower disc 800 B will be thinner from the inner periphery toward the outer periphery of the disc 800 B, and configured to match the radial thickness of the facing permanent magnets 20 Aa, 20 Ac, 20 Ae. Note that the permanent magnet and the opposing magnet projection may form part of the magnetic circuit as described above.
[0112]Further, as shown FIG. 9A , FIG. 9B , FIG. 5C and FIG. 5B , the permanent magnets 20 Aa, 20 Ac, 20 Ae are shaped the same as the shape of the opposing magnetic members 10 Aa, 10 Ac, and 10 Ae. That is, the shape and dimensions in the facing direction between the magnetic members 10 Aa and the permanent magnet 20 Aa are the same. The permanent magnet 20 Ac and the magnetic member 10 Ac as well as the permanent magnet 20 Ae and the magnetic body 10 Ae are shaped and sized the same in the facing direction.
[0113]In addition, the radial thickness LTH 2 , LTH 4 , and LTH 6 of the heat conductive members 30 Ab, 30 Ad, and 30 Af disposed on the upper disk 800 A of the magnet/heat conductive member arranged plate 800 is made sequentially thicker from the inner periphery to the outer periphery of the circular disc 800 A.
[0114]This is to keep the mechanical strength of heat conductive member 30 Ab, 30 Ad, and 30 Af. Since the speed of the disc 800 A at outer peripheral side is faster than the inner peripheral side, a larger centrifugal force is received at the outer peripheral side of the heat conductive member. Therefore, increasing the radial thickness of the heat-conducting member 30 Ab, 30 Ad, 30 Af is advantageous in maintaining mechanical strength. Further, the length of the circumferential of heat conducting member 30 Ab, 30 Ad, the 30 Af, are successively longer toward the outer periphery from the inner periphery of the circular plate 800 A. This is because the lower the thermal resistance of radial heat-conducting member 30 Ab, 30 Ad, and 30 Af. Therefore, it is determined by the thickness of the heat conducting member 30 Ab, 30 Ad, of 30 Af placed interval magnetic material 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, of 10 Af. The shapes of the heat conductive member 30 Ab, 30 Ad, of 30 Af are adapted to the respective shape of the gap of the magnetic member/body Aa- 10 Ab, 10 Ac- 10 Ad, of 10 Ae- 10 Af.
[0115]In addition, when the radial thickness of the heat conductive member 30 Ab, 30 Ad, and 30 Af becomes thick, thermal resistance in the radial direction of the heat conductive member will increase. However, since the circumferential dimension of the magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, and 10 Af is set longer from the inner periphery to the outer periphery, the cross section A of the heat conductive members 30 Ab, 30 Ad, and 30 Af as seen from the radial direction becomes large and the respective heat resistance of the heat conductive members 30 Ab, 30 Ad, and 30 Af will be substantially the same.
[0116]Under such circumstances, in the present embodiment, as is shown in FIG. 9A , the radial thickness of the heat conductive members 30 Ab, 30 Ad, and 30 Af, LTH 2 , LTH 4 , and LTH 6 are set to such thickness to meet the relationship; LTH 2 <LTH 4 <LTH 6 . Further, the circumferential length of the heat conductive members 30 Ab, 30 Ad, and 30 Af is set in accordance with the shape of the respective gaps formed between magnetic members 10 Aa- 10 Ab, 10 Ac- 10 Ad, and 10 Ae- 10 Af, respectively so as to be successively longer from the inner periphery to the outer periphery of the disc 800 A.
[0117]As described above, with the dimensions of the magnetic members, the magnetic circuits, and the heat conductive members varied outwardly from the rotational center, a magnetic refrigerator 500 according to the embodiment shown in FIG. 10 may be obtained. That is, the radial thickness of the magnetic members is thinner from the inner periphery toward the outer periphery, all the magnetic members 10 having the same heat capacity, i.e. volume. Further, with respect to the permanent magnet and magnetic projection (not shown) constituting a magnetic circuit, similar to magnetic members, the radial thickness is thinner from the inner periphery toward the outer periphery so that all magnetic members are configured to generate the same amount of heat. Moreover, with respect to the heat conductive members 30 , the radial thickness is thicker from the inner periphery toward the outer periphery so that between the magnetic members, magnetic member and the low-temperature side heat exchange unit 40 A, and the magnetic member and the high-temperature side heat exchange unit 40 B, heat transfer will be efficiently performed.
[0118]The principle based on which the magnetic refrigerator 500 pertaining to the present embodiment constructed above performs magnetic refrigeration is the same as that explained with reference to FIGS. 3A-3E .
[0119]As described above, according to the magnetic refrigerator pertaining to the present embodiment, the heat capacity of each magnetic member is set equal and due to reduction in heat resistance of each heat conductive member, the heat transport capacity may be increased and the refrigeration performance will be improved (compared to the conventional technique, 100% increase). Further, since the shape of the permanent magnet corresponds to the shape of each magnetic member, useless part of the permanent magnet is not present and the lightweight magnetic refrigerator may be available.
[0120]Further, since the radial thickness of the heat conductive member is made thicker as it is located on outer peripheral side, it is possible to improve the strength of the heat conductive member to thereby improve the reliability of the magnetic refrigerator.
[0121]Furthermore, since only the positive magnetic material is used which is inexpensive and has greater magnetocaloric effect compared to the negative magnetic material, it is possible to improve the refrigerating capacity and to contributes to cost reduction.
[0122]Next, the specific configuration of the magnetic refrigerator according to the third embodiment will be described with reference to FIG. 11 . In the magnetic refrigerator in the third embodiment, instead of the same volume of the magnetic member as in the second embodiment, by setting the volume of the magnetic member smaller outwardly from the center of rotation, it is intended to keep the heat transfer loss smaller.
[0123]In the present embodiment, as shown in FIG. 11 , in the magnetic body arranged plate 700 , the volume of the magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, and 10 Af is set smaller in the direction toward the outer periphery from the inner periphery of the magnetic body arranged plate 700 . The reason to have the volume of magnetic members smaller in the direction from inner periphery to the outer periphery is to reduce the heat transfer loss achieved by successively making the heat capacity of the magnetic member smaller.
[0124]In order to reduce the heat transfer loss, in the present embodiment, as is shown in FIG. 11 , the radial thickness LM1, LM2, LM3, LM4, LM5, and LM6 of the magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, and 10 Af is set such that the following relationship may be established; LM1>LM2>LM3>LM4>LM5>LM6. And yet, the thickness of these magnetic members are further required to meet the relationship in which the heat capacity QM 1 , QM 2 , QM 3 , QM 4 , QM 5 , and QM 6 of all magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, and 10 Af are defined in the following relationship; QM 1 >QM 2 >QM 3 >QM 4 >QM 5 >QM 6 . Therefore, the radial thickness LM1, LM2, LM3, LM4, LM5, and LM6 of the magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, and 10 Af according to the present embodiment is even more thinner in the radially outward direction compared to the radial thickness is, 10 Aa in the second embodiment, 10 Ab, 10 Ac, 10 Ad, 10 Ae than LM1, LM2, LM3, LM4, LM5, LM6 thickness LM1, LM2, LM3, LM4, LM5, and LM6 of the magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, and 10 Af in the second embodiment.
[0125]The above situation is also true for the magnetic body units 200 B, 200 C, . . . , 200 G, . . . and 200 L shown in FIG. 5B .
[0126]As shown in FIG. 11 , the radial thickness of the permanent magnets 20 Aa, 20 Ac, and 20 Ae disposed on the upper disc 800 A of the magnet/heat conductive member arranged plate 800 is configured to be thinner in the direction from the inner periphery to the outer periphery, and corresponds to the radial thickness of the magnetic members 10 Aa, 10 Ac, and 10 Ae. Further, the radial thickness of the magnetic projections 20 Ab, 20 Ad, and 20 Af disposed on the lower disc 800 B is set thinner in the direction from the inner periphery to the outer periphery, and correspond to the radial thickness of the opposing permanent magnets 20 Aa, 20 Ac, and 20 Ae. Note that the permanent magnet and the opposing magnetic projection form part of the magnetic circuit as described above.
[0127]Further, as shown FIG. 11 , FIG. 5C and FIG. 5B , the permanent magnets 20 Aa, 20 Ac, 20 Ae are shaped in the same dimension or contour as the magnetic member 10 Aa, 10 Ac, and 10 A. In other words, the shape and dimension of the permanent magnet 20 Aa and the magnetic member 10 Aa are the same in the facing direction. Also, with respect to the permanent magnet 20 Aa and the magnetic member 10 Ac, the permanent magnet 20 Ae and the magnetic member 10 , the shape and dimension in the facing direction are the same.
[0128]In addition, the radial thickness LTH 2 , LTH 4 , LTH 6 of the heat conductive members 30 Ab, 30 Ad, and 30 Af disposed on the upper disc 800 A of the magnet/heat conductive member arranged plate 800 is set successively thicker from the inner periphery to the outer periphery of the disc 800 A. This is intended to secure sufficient strength of the heat conductive members 30 Ab, 30 Ad, and 30 Af. Since the speed of the disc 800 A at the outer periphery side is faster than the inner periphery side, the centrifugal force exerted is greater at the outer periphery side. Therefore, the structure in which the radial thickness of the heat conductive members 30 Ab, 30 Ad, and 30 Af is made thicker is convenient for holding the mechanical strength. Further, the circumferential length of the heat conductive members 30 Ab, 30 Ad, and 30 Af are set progressively longer form the inner periphery of the disc 800 A to the outer periphery. This arrangement is intended for reducing the heat resistance in the radial direction of the heat conductive members 30 Ab, 30 Ad, and 30 Af. Therefore, the placement or installation interval of the magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, and 10 Af is decided based on the thickness of the heat conductive members 30 Ab, 30 Ad, and 30 Af. The shape of the heat conductive members 30 Ab, 30 Ad, and 30 Af are adapted to the shape of the respective gap between magnetic members, i.e., 10 Aa- 10 Ab, 10 Ac- 10 Ad, and 10 Ae- 10 Af.
[0129]In addition, when the radial thickness of the heat conductive members 30 Ab, 30 Ad, and 30 Af becomes thick, thermal resistance in the radial direction of the heat conductive member increases. However, because the circumferential dimension of the magnetic members 10 Aa, 10 Ab, 10 Ac, 10 Ad, 10 Ae, and 10 Af is set longer toward the outer periphery from the inner periphery, the cross sectional area A of the heat conductive members 30 Ab, 30 Ad, and 30 Af becomes large so that respective heat resistance of the heat conductive member 30 Ab, 30 Ad, and 30 Af may be set to be substantially same.
[0130]Given the circumstances described above, in the present embodiment, as in the second embodiment, as shown in FIG. 11 , the radial thickness LTH 2 , LTH 4 , LTH 6 of the heat conductive members 30 Ab, 30 Ad, and 30 Af are set such that the following relationship may be established; LTH 2 <LTH 4 <LTH 6 . Further, the circumferential length of the heat conductive members 30 Ab, 30 Ad, and 30 Af is set to be successively longer so as to match the shape of respective gaps between the magnetic members; 10 Aa- 10 Ab, 10 Ac- 10 Ad, and 10 Ae- 10 Af.
[0131]The principle based on which the magnetic refrigerator pertaining to the present embodiment structured above is the same as that explained above with reference to FIGS. 3A-3E .
[0132]As described above, according to the magnetic refrigerator pertaining to the present embodiment, it is possible to gradually decrease heat transfer loss since the heat capacity of each magnetic member is set to be successively smaller from the side of inner periphery toward the outer periphery.
[0133]Next, the specific configuration of the magnetic refrigerator according to the fourth embodiment will be described with reference to FIG. 12 and FIG. 13 . Contrary to the magnetic refrigerator according to the second and third embodiments, the magnetic refrigerator according to the present embodiment is structured to rotate the magnetic body while fixing the magnetic circuit and the heat conductive member of the magnetic refrigerator.
[0134]As shown in FIG. 12 , in the present embodiment, the magnetic body arranged plate 700 is supported so as to be rotatable around the low-temperature side heat exchange unit 40 A about its center portion as rotation axis. The magnetic body arranged plate 700 is rotated by the driving unit. On the other hand, the magnet/heat conductive member arranged plate 800 is fixed to the high-temperature side heat exchange unit 40 B. Between the magnet/heat conductive member arranged plate 800 ( 800 A, 800 B) and the high-temperature side heat exchange unit 40 B, an insulating material 535 B is interposed in order to prevent transfer of heat between the magnet/heat conductive member arranged plate 800 and the high-temperature side heat exchange unit 40 B. Note that the shape of the magnetic body, the magnetic circuit, the heat conductive member is the same as in the second and third embodiments.
[0135]When the magnetic bod arranged plate 700 of the magnetic refrigerator 500 structured above rotates, as shown in FIG. 13 representing a A-A cross sectional view of FIG. 8 , heat transfers from the magnetic member 10 Aa to the magnetic member 10 Ab, from the magnetic member 10 Ac to the magnetic member 10 Ad, from the magnetic member 10 Ae to the magnetic member 10 Af, respectively through the heat conductive members 30 Ab, 30 Ad, and 30 Af. Note that the state of heat transfer in each magnetic body unit is the same as that shown in FIG. 11 .
[0136]Thus, according to the magnetic refrigerator pertaining to the present embodiment, since both the combination of the permanent magnet and the magnetic projections forming the magnetic circuit and the magnet/heat conductive member arranged plate 800 having the heat conductive member are fixed, and the magnetic body arranged plate 700 forming the magnetic body only is subject to rotation, the start-up time for the magnetic refrigerator is faster because the weight of the magnetic body arranged plate 70 is light compared to the weight of the magnet/heat conductive member arranged plate 800 .
