Design And Dynamic Analysis Of Rigid-flexible Composite Gear Pair Based On Metal-rubber Materials

This research is funded by the military supporting project from "Development of a high precision gear pair". With the rapid development of military equipment, it has a higher requirement for transmission reliability and accuracy of gear reducer. For require performance of military equipment, and outstanding problems of conventional retarder, Professor Wang Jiaxu, from Chongqing University, has invented a highly reliable, lightweight and high precision planet reducer with fewer tooth difference rubber which called ―alloy filtering gear reducer‖. But the rubber alloy as a non-metallic base material, has worse strength, stiffness and temperature performance than metal material, which prevents the application of filtering gear reducer. The metal-rubber material can stable and reliable work in-70℃~300℃ environment while the mechanical properties do not change greatly. In this paper, we study the composite gear pair by use of metal-rubber material as the elastomer, and improve the transmission performance through rational design. The main contents of this thesis are as follows:① Based on the compression and damping performance characteristics of metal-rubber material and combining the deformation coordination theory, we have established a complete design calculation process about metal-rubber composite gear pair. The design process uses the relative density of the metal-rubber materials as the most important variables and calculate two ways, i.e. the torsional stiffness, starting frictional torque and dynamic performance of the composite gear pair. After comparison the results of the two methods and verifying no apparent conflict, summarizes the processing parameters of the metal-rubber composite gear. Taking the error of previous calculation into account and in order to carry out comparative experiments to verify the reasonability of previous calculation, we designed 5 different metal-rubber composite gear pairs with different gaps and different relative densitt.② Early in the design the kinetic analysis was introduced to guide and optimize the design. The support bearing, drive shafts and metal rubber elastomer were equivalent to support stiffness and damping elements. Then using the no-friction gear meshing model, we have established 6-DOF nonlinear vibration model of the three main components of a pair of metal-rubber composite gear pair in accordance with the lumped mass method. Then reduce the order of the differential equations above and use Matlab programming to solve. Then use PSO to carry out multi-objective optimization by treat the equivalent stiffness and damping of metal-rubber elastomer as independent variables, the vibration response of composite gear pair as constraint and the minimum RMS value of vibration acceleration as target. Substituted the results of PSO into the above process to the next step calculation.③ Consider the structure of composite gear pair and use Abaqus finite element software to carry out heat deformation analysis in high and low temperature environments. Then carry out deformation and compatibility design by consider the gear tooth thickness error, gear runout, shaft eccentricity error, radial clearance of support bearing previous thermal deformation analysis results to ensure the accuracy and reliability of the transmission. Calculate the amount of preload at room temperature and check the transmission accuracy in low temperature and the reliability of composite gear pair in high temperature. The results showed that the preload of 5 composite gear pairs not only to ensure hysteresis requirements in low temperature, but also to guarantee the gap between the gear ring and the shaft in high-temperature to ensure that the composite gear pairs does not occur stall or stuck fault.④ Consider the forming process of metal-rubber materials and combined with the previous calculation results, we design a set of stamping tools of metal-rubber elastomer. We creative use the gear ring and shaft of composite gear pair as the mould cavity so that the molded metal rubber elastomer no longer need to assemble.⑤ Carried out some experiments by using 2# complex gear pair and multifunction drive and friction experiment platform. The experimental results show that vibration acceleration of the 2# complex gear pair is significantly less than traditional metal gear pairs. Then tested the complex gear pair under different center distance. The friction torque of complex gear pair increases with the increase of preload distance while the acceleration trends to decline after rising.