Investigation of end effect in integrated permanent magnetic damper for cylinder block–valve plate pair in axial piston pump

Abstract

The present work develops an integrated permanent magnetic damper (IPMD) to apply magnetic torque on a cylinder block, which makes it possible to suppress eccentric wear of the cylinder block–valve plate pair in an axial piston pump. Then, the structure and working principle of the IPMD are described. According to the relationship between the axial and the radial magnetic pole gap, the corresponding end flux tube models are established. Based on the principle of micro-displacement, the axial magnetic force and torque output by IPMD are derived. After separating from the relevant structures inside the pump, to ensure the effectiveness of the results, the test method of IPMD independent of the axial piston pump is provided. To make a more comprehensive analysis of the magnetic bearing characteristics, the prototype of IPMD is manufactured and tested. The influence of the end effect of IPMD on the residual hydraulic torque under different discharge pressures is studied. The results verified the correctness of the theoretical analysis, which have important guiding significance to improve the reliability of the cylinder block–valve plate pair in the axial piston pump.