Through regular testing for the same position in a vertical machining center by ball bar,the data sequence of Y axis backlash value of machining center was obtained.The past and now known or unknown the information of Y axis backlash value is regarded as a grey system.The mathematical model of gray system was established.Time series data of monotonically increasing was generated by accumulating.The albino form of differential equations of grey system GM(1,1)was established.Then the cal-culation accuracy was improved by correcting of residual model.The corrected model GM(1,1)is used to predict the variation of Y axis backlash values.For the maintenance at late stage of machining center,eliminating backlash provide a basis.

以SL50数控车床为例,对斜床身贴塑导轨的工作情况做了分析.通过对影响斜床身数控车床贴塑导轨直线度的多种因素的分析,将其过去及现在已知的或非确知的情况,视作一个灰色系统.通过激光干涉仪定期检测贴塑导轨直线度的误差值,构成一个原始等间隔数据序列.按灰色系统建模法建立灰色系统GM(1,1)模型的白化形式微分方程,揭示贴塑导轨直线度的发展变化规律.再通过残差模型的修正,提高了计算精度.修正后的GM(1,1)模型可用来预测贴塑导轨直线度的误差值.

为了建立加工中心的最佳维修周期与有效度之间的数学模型,以确定最佳维修周期,通过对立式加工中心常见故障的类型及原因分析,建立了平均故障率与规定考察时间之间的关系曲线,分析出了加工中心的平均故障率随着时间的增加而逐渐增大,建立了预防性维修即事前维修与事后维修的可靠性维修间隔时间模型;基于平均故障率函数为递增函数,按有效度为最大时可求出最佳维修周期,并通过实例,运用可靠度函数的数值积分方法,计算出了加工中心的最佳维修周期.研究结果表明,所建立的计算方法为数控机床的最佳维修周期的确定提供了一种有效途径.

本棘轮机构控制的拦蓄门是一种纯机械式的装置,利用自身拦蓄的水流对下流管道实施冲洗,不需要外部提供动力源和远程控制.阐述了管道拦蓄门的工作原理,完成了拦蓄门的方案设计,通过双棘轮控制机构,实现了拦蓄门的顺序动作过程,即在蓄水过程中锁定拦蓄门不上升,当水位上升到预定位置时解锁使拦蓄门快速上升,并将拦蓄门锁定在最高位置,当水位下降到预定位置时解锁放下拦蓄门.通过产品样机的试制和运行,表明其工作可靠,拦蓄和冲洗的效果好,制造和运行的成本低.

The past and now known or non ascertain information of spindle rotation accuracy of CNC lathe, regarded as a gray sys-tem. For five of the same type CNC lathe, radial motion errors and axial motion errors of the spindle, and motion errors of chuck face were detected at regular intervals. These errors constituted the raw data equally spaced data series. Model of Grey System GM( 1, 1) was established. Differential equations of gray system were solved. The result shows that correction by means of residual model improves accuracy. And the modified GM(1, 1) model can be used to forecast the life of spindle rotation accuracy of CNC lathe, which provides evidence for maintenance cycle for the latter, replacement of spindle bearings and recovery of spindle rotation accuracy on CNC lathe.

通过以SL50型数控车床的主轴组件为例,深入分析了产生主轴回转误差运动的原因,提出该数控车床主轴轴承的预紧力界定范围.对该数控车床主轴轴承磨损情况做了可靠性统计分析,建立了主轴回转精度寿命的可靠度模型,主轴轴承磨损量与其工作小时数几乎成线性关系.在该数控车床工作15000小时和20000小时后,分别检测了主轴径向跳动的误差、主轴轴向窜动误差和卡盘端面跳动误差,对主轴回转精度的下降情况做了统计分析,并进行了回转精度可靠度计算.

为了获得三叶渐开线罗茨风机基圆半径变化对风机性能的影响关系,首先从几何原理角度,分析了渐开线基圆变化对风机转子啮合渐开线的影响,给出了符合啮合条件的渐开线基圆半径变化范围,及不同基圆半径对转子面积利用率系数的影响情况.在此基础上利用数值分析方法,对同种叶型不同基圆半径时的风机转子流场进行数值计算,运用动网格技术分析了风机内部的压力场、涡的强度变化和进气口质量流量变化情况.模拟结果表明:同种叶型渐开线基圆半径增加,能够削弱涡的强度和速度,增加进气口质量流量,提高风机效率,因此风机生产企业设计时应选择较大的渐开线基圆半径.

本文从优化高职机械类专业技能型人才培养方案的设计和方案的实施与保障、深化专业课程开发和教学内容改革、提高学生的学习效率、增强学生的动手能力、丰富教学评价手段、提高学生的学习动力等几个方面进行了探讨和研究。

Based on the structure characteristics of the MOTOMAN-UP6 robot,the AutoCAD model and D-H coordinate of the robot were built.According to the theory of D-H matrix,the mathematical model of the forward kinematics problem was established by homogenous transformation,which was from the coordinate system of mechanical interface to the coordinate system of UP6 plinth.After measuring the position posture of the coordinate system of mechanical interface with AutoCAD platform,the mathematical model and the CAD simulation were verified mutually in a comparative all-round way.Simulating the UP6 robot kinematics by ADAMS software,the real time results of displacement,speed and acceleration of robot in different conditions were obtained.So these have significance to joint-robot on motion performance study.

In order to improve the capability of small and medium enterprises to design new products,the meshing of three-blade root blower was analyzed in detail,and a convenient way to design the blade shape of a rotor was proposed.Firstly,the pitch pressure angle according to the radius of base circle and center distance was determined;secondly,involute meshing rotor's start and end points were determined;thirdly,the roll angle of involutes' line occurred on the base circle was determined;fourthly,the rotor involutes' position was determined.Then,according to R0=2Z(R-a)·ξ/π(0.787 8≤ξ≤0.927 7),based on the best area utilization factor,the optimal value of R0 was determind by modern optimization algorithms.Finally,taking 3L4 series roots blower as example,details of the rotor design and optimization solution process was introduced.

According to the structure characteristics of the PUMA560 robot,the AutoCAD model and D-H coordinate of the robot are built.The mathematical model of the forward kinematics solution is established based on the D-H coordinate transformation.After measuring the position posture of the coordinate system of workpiece center with AutoCAD platform,the mathematical model and the CAD simulation are verified mutually in a comparative all-round way.So these make positive significance of industrial robot on motion performance.

NC Code transforming system is to solve the problems of sharing ISO6983 NC codes.According to the basic-element theory in extension theory,three kinds of multiple elements were defined: basic characteristics of machine tools,NC code functions and NC code format.These multiple elements were saved in the system-information module.The solving key-questions module in the system converted function parameters of NC codes,decomposed code functions and transformed the code format.The importing-codes module chose types of machine tools by means of motion transformation matrix,imported codes and analyzed the morphology of NC codes.The creating intermediate-files module generated STEP files for converting NC codes.The exporting-codes module achieved optimal choice and transformation of NC codes.The system performance depends on the maturity of three multiple-elements and key-questions' solutions.

During the new era,educating college students requires accurate positioning,clear identification of education direction,refining of characteristics in order to form a practical teaching and learning system based on ability fostering.This article elaborates the reform and exploration that School of Mechanical Engineering of Nantong Vocational College has made in practical teaching and learning: comprehensive planning,step by step implementation,improve on and off campus practice teaching base,create a good atmosphere of technology application and practical creative education;establish a people-oriented teaching philosophy and inspire students' potential of practical innovation;meanwhile,establish reasonable appraisal system of teaching and learning from the aspect of practical teaching process such as experiment and practice,curriculum design and graduation design to improve practical abilities of vocational students.

In order to improve the capability of small and medium enterprises in designing new products,a reverse design methodology based on NC program is introduced.The usage of the methodology includes three phases: parts′ approximate geometric graph acquisition,reverse design and optimization of higher mode curve.Then a reverse design example of 3L4 mode roots blower is illustrated.We described in detail the procedure of NC program,the part approximate shape,the circular fitting curve,the involute function and the rooters′ curve optimization design.

With regard to the current weak situation of CNC machining accuracy field well as the local characteristics of Nantong,this paper focuses on the construction of key laboratory of CNC machining accuracy in Nantong Vocational College.It identifies the research direction of key laboratory,technology project and equipment for small and medium enterprises in details,which eventually provides the college students with skill-training programs to improve local economy and strengthen the core competence of the college.

In order to improve the machining accuracy of Roots blower,a method based on error compensation in NC program is introduced to solve the lack of planer rigidity.Then taking 3L5 mode roots blower for example,the procedure of average circle fitting involute curve is described in detail.On the/this foundation,the error area is shifted to execute secondary correction for ensuring the final machining accuracy.The application proves the method is a feasible way to machine high quality rotors for economic CNC planner.

Based on the linear vibration theory,the unbalance response of the system is calculated,the results show that the misalignment rotors have a great effect on the unbalance response of the system under both rolling and sliding bearings,the unbalance response occurres mainly in the vicinity of the critical speed and it is very significant at this moment,while at work speed,it is rather smaller.

Firstly, taking the case of MJ-50 NC lathe, the spindle instantaneous turning position error is classified as axial shifting, radial moving up and down and angular swing. Secondly, based on above foundation, the evaluation indexes about spindle turning accuracy are set up. Finally, the main factors which may affect spindle turning accuracy are studied. The application example illustrates a new method for determining the machining accuracy range of NC machine tool.

This paper introduces the approach to analyze three-ax error of the VMCL600 vertical numerical controlled machine center,and builds up a figure model of such errors based on the instruments mentioned above.Indeterminate hypotheses are eliminated from the figure model.This can help to solve the problem more simply and conveniently.By using the laser interferometer,9 displacement errors at 9 rectilinear motions are measured along three-axis,and corresponding 9 linear degree errors are also measured.Linear degree er-ror and corresponding displacement error must be measured at the same line.The results indicated that the precision and efficiency of length-measuring are improved greatly.

Now China has carried out the plan to promote industrialization with the help of information technology, and applying information technology in enterprises is the basis of this aim. To meet this requirement and serve local economy, new method of cultivating personnel shall be researched, the teachers 'quality should be improved, and modern practice should be applied in higher vocational education.