The investigation purpose: simplification and ensuring tooling high performance of two-pair gear trains in machines with change gears. Methods used: numerical experiments for the characteristics definition of change gear sets in gear trains, a comparative analysis of different sets characteristics, a result visualization in a table form. Relevance of the method offered is substantiated with considerable labor intensity in the definition of the gear combination in gear trains by existing methods based on tables use mainly through possible way selection. Novelty: there are offered special algorithms of setup calculations decreasing operation time for the choice of gear combinations of gear trains. Basic results: there are developed computer programs for the definition of gear train combinations required and an electronic directory for machine-tool two-pair gear train setups recommended for use by workers of technological departments and in design service in production activities of engineering and motor car repair companies, in research centers and colleges (in thesis investigations, in training processes of engineering experts).
The paper considers a technique that allows to increase the efficiency of solving various types of production tasks based on simulation modeling. The technique considers the process of engineering modeling of technological system components in accordance with conceptual hierarchical levels, which with the deeper level provide an approximation of the simulated object from the initial correspondence in the form of equipment contours to the maximum in the form of a 3D component model based on 3D scanning. This technique allows to choose the most adequate option of modeling the technological system components, corresponding to the complexity of the production task solved by simulation modeling. The application of the technique in the design and engineering services of a machine-building enterprise allows to arrange the modeling process, select all its stages, assign performers, check the execution of the modeling process, ensure that the models correspond to the production task being solved. The technique effectiveness is confirmed by the given examples of solving production tasks of diverse complexity – simulation modeling of gear milling of helical bevel gears and circular tooth pulling. The purpose of the paper is to reduce the complexity of building 3D models of technological systems by engineering services of machine-building enterprises for solving production problems of diverse complexity thanks to the hierarchical structuring of input design information for building 3D models of a technological system and solved production tasks. Research methods: functional differentiation of processes. Research results and novelty: reducing the duration of solving production tasks of diverse complexity by decreasing the time of 3D modeling of technological systems. Conclusions: rational arrangement of engineering modeling based on the hierarchical structuring of input design information for building 3D models of a technological system and solved production tasks allows to reduce the duration of engineering modeling up to two times.
To improve functional properties of pre-eutectic silumins there are used many different methods having a complex effect upon processes of structure formation and physical-mechanical properties of alloys. In this paper there is offered a method for alloy operation characteristics increase by the example of wear-resistance by the impact of nanosecond electro-magnetic pulses (NEMP) upon silumin melt AK7ch (AL9). Melt illumination was carried out with the generator (NEMP) (GNI-01-1-6) submersible rod radiator. The melt was overheated to 900ºC and processed with NEMP with the length up to 25 min after that it was cooled at a rate of 20ºC/min. Slow cooling contributed to the formation of a structure close to equilibrium. Cylindrical ingots with a diameter of 0.06 m (60mm) and a height of 0.06 m (60 mm) were obtained. Wear-resistance was defined on a cross cut of ingots according to GOST 23.208-79. As a standard of comparison were used non-irradiated samples of silumin. It is defined that melt NEMP processing changes considerably parameters of crystallization, structure formation and increases silumin properties. At abrasive wear, silumin wear-resistance changes from the duration of melt electro-pulse processing according to an extreme dependence with the evident maximum at melt irradiation in the course of 15 min. At that in the edge area of the ingot wear-resistance increases by 1.54 times, and in the central one – by 1.34 times. This effect is explained by the fact that during melt NEMP processing during 15 min the characteristics of alloy micro-structure change considerably: morphology and dimensions of structural constituents. At that there is formed a qualitatively new fine structure of a non-dendritic type which ensures maximum values of alloy wear-resistance. The data obtained allow developing technology of wear-resistant silumin fusion intended for operation under abrasive wear conditions.
The purpose of this article is to develop a model for managing duplicates at a motor transport if there is an insurance reserve. The task is to minimize the total costs (losses) at the motor transport enterprise. For an optimal model of duplicates management, regardless of the supplier and the time of delivery, the insurance stock in the warehouses of motor transport enterprises will satisfy the demand for spare parts necessary for rolling stock. Also, taking into account the determination of the optimal size of duplicates, the prediction of sudden failures, as well as statistics maintained in the Procurement service of motor transport enterprises, the volume and frequency of orders for duplicates become known. Determining the size of duplicates batch of various classification and quality allows the MTS (material and technical support) services of motor transport enterprises to ensure not only an uninterrupted transport process, but increase the coefficient of technical readiness and save on previously unclaimed stocks (surpluses) ensuring the effective distribution of financial resources. Further research in this area will be aimed at determining duplicates quality, supplied to the motor transport enterprise and developing methods for assessing the risk of the impact of defects in spare parts on failures and further consequences.
The purpose of the work is to assess the safety of passenger cars in case of an emergency rollover on the body of railroad tracks. The paper introduces a method for predicting injury of railway transport passengers as a result of swinging over the wagon on the body of railroad tracks. The method of research is mathematical modeling of scenarios of swinging over the wagon on a flat bottom or earth tramp of the railway track. A model of a passenger compartment has been developed, which is supplemented with models of a roomette, hand luggage and an anthropometric dummy. The originality of the work is the use of mannequin models for an accident with the rollover of a compartment car on the body of the railroad tracks and obtaining data on the interaction of fit models and a compartment car. The result of the study is the reported values of possible injury to passengers during an emergency rollover of a passenger car. Namely, the values of the head injury criterion, cervical vertebrae, breast and hips of the crash test dummy have been obtained. In comparison of the two considered scenarios of swinging over the wagon, the value of the head injury criterion for overturning the car on an inclined surface is 15% higher, the neck injury criterion is 30% higher, and the hip and chest injury criterion is 23% higher for mannequins on the upper shelves of the compartment due to their interaction with hand luggage. The obtained values do not exceed critical ones. The most dangerous positions of the mannequin model in the compartment of the car are revealed. Conclusions concerning the sufficient safety of the passenger car are formed and recommendations for the development of additional technical solutions to improve the safety of passenger cars are given.
