Optimization Of Radial Dimension And Tolerance Of Cycloid Needle Wheel Mechanism Of Cycloid Hydraulic Motor

Cycloidal pinwheel mechanism is the core component of cycloidal hydraulic motor.At present,the interchangeability of cycloidal pinwheel mechanism is not high,so it needs to be matched when assembling.At the same time,there is a gap in mechanical efficiency and volume efficiency between domestic and foreign cycloidal motors.Based on the above problems,this paper takes the cycloidal pinwheel mechanism of BMP2 cycloidal hydraulic motor as the research object,optimizes its parameters and tolerances,and provides a theoretical basis for solving the problem of selection and allocation of cycloidal pinwheel mechanism and total efficiency of the motor.The main research contents are as follows:(1)The tooth profile parameters of cycloidal pinwheel mechanism are optimized.The structure and working principle of cycloidal motor are introduced.The main factors affecting the theoretical displacement and output torque ripple of cycloidal motor are analyzed.Based on the mathematical model of cycloidal gear and stator profile curve in cycloidal pinwheel mechanism,an optimization model with total efficiency as objective function,stator distribution circle radius and pinwheel radius as independent variables was established.The optimal tooth profile parameters of the function were obtained by genetic algorithm,and the total efficiency of cycloidal pinwheel mechanism was increased to 98%.Based on ADAMS software,the dynamic simulation analysis of the optimized cycloidal pinwheel mechanism is completed.The simulation results show that the optimized mechanism not only has better performance,but also has good dynamic characteristics.(2)Tolerance analysis of cycloidal pinwheel mechanism is carried out.The dimension chain equation of cycloidal pinwheel mechanism is established.The dimension chain is analyzed by extremum method,probability method and Monte Carlo method.The size distribution range of closed ring is studied,and the success rate of assembly is calculated.The interchangeability of parts is compared and evaluated intuitively by the success rate of assembly.The results show that the assembly success rate of cycloidal needle wheel mechanism of BMP2 motor before optimization is 64.7%,which is less than 99.73% required for large number interchange.Therefore,tolerance optimization of cycloidal needle wheel mechanism is needed.(3)The tolerance of the ring is optimized.A mathematical model was established with the optimization objective of processing cost and quality loss and the constraint condition of tolerance accumulation.The genetic algorithm is used to optimize the tolerance of the basic size of the ring.By Monte Carlo method,the size distribution range of the closed ring is solved again,and the distribution range meets the large number interchange,which proves that the optimization results meet the interchangeability requirements.(4)The optimal design scheme is verified.The interchangeable assembly was completed by using multiple sets of optimal design parts.According to the actual assembly process,the optimized cycloidal needle wheel mechanism no longer needs matching operation,which shows that the optimization scheme improves the interchangeability of various parts.By comparing the performance of the motor with that of the motor without optimization design,it is found that the total efficiency of the motor after optimization design is improved,and the rationality and practicability of the optimized scheme are verified again.