Abstract:

The design of the floating valve plate effectively addresses the problem of cylinder block tilting at high speed in axial piston pumps/motors， aligning with the trend towards high-speed development of axial piston pumps/motors and gaining attention in recent years. However， there is still a lack of systematic dynamic modeling and dynamic characteristic research for the piston pump/motor system designed with floating valve plate， which limits the design of floating valve plate piston pump/motor products. A comprehensive parameterized dynamic model of the system that considers its detailed structural features is established for the piston pump motor system designed with floating valve plate. The study focuses on the laws of dynamic changes of the pressure in the high-pressure oil circuit and the auxiliary hydraulic chambers， and the model's correctness is verified through bench tests. The results show that the high-pressure oil circuit exhibits a "sharp drop and slow rise" characteristic of "sawtooth" pressure pulsations， which are intense. At a pump speed of 1 000 revolutions per minute （r/min）， the average pressure in the high-pressure oil circuit at 20 and 40 MPa pressure levels results in pulsation amplitudes as high as ±1.5 and ±3 MPa， respectively. The fluid pressure in the auxiliary hydraulic chamber exhibits a dynamic change pattern of "rapid follow-up and slow decline，" meaning that once the auxiliary hydraulic chamber is connected with the high-speed rotating piston chamber， its fluid pressure almost immediately follows the piston chamber pressure changes without attenuation or lag. After disconnection from the piston chamber， it can still maintain the chamber pressure effectively.

Key words: axial piston pump/motor, floating valve plate, high pressure oil circuit, auxiliary hydraulic chamber, dynamic modeling and analysis