A study on the relative sliding characteristics of the joint bearings in airborne high-pressure wobble plate compressor

Abstract

Wobble plate compressors are favored in aviation for compactness. The joint bearing on a wobble plate is a critical component of the drive system, but its motion characteristics are complex, and currently lacking a motion model. This study develops a composite motion model for the wobble plate in airborne wobble plate compressors with both bevel gear and roller-straight groove anti-rotation designs, using a microelement method. The result shows that the wobble plate simultaneously rotates around an instantaneous axis within its plane and its normal axis, exhibiting similar behavior in both anti-rotation types with minor deviations below 5 % in angular velocity and 20 % in axis when the inclination angle is less than 25°. The motion characteristics of the joint bearing's ball socket relative to the ball head mirror the wobble plate, with equal rotational velocities and parallel axes. This theoretical model is validated through ADAMS simulations, achieving a high level of accuracy with less than 1.5 % deviation in maximum relative sliding velocity at the selected point in both anti-rotation structures. The research further investigates the influence of compressor rotation speed, wobble plate inclination angle, and joint bearing radius on the maximum relative sliding velocity, revealing an approximately proportional relationship. The area with the maximum time-averaged relative sliding velocity is located near the bottom of the ball socket, suggesting a potential wear hotspot. The experimental observation of morphology confirms this. This research provides a theoretical foundation and technical support for wear analysis and optimized design for joint bearings in wobble plate compressors.