Structural design and characteristic analysis of three-oil port axial piston pump

Aiming at the problem that the flow rate of the two cavities of the differential cylinder does not match and it is not easy to achieve pump control, the team proposed the asymmetrical distribution principle of the axial piston pump with three ports, which can compensate for the flow difference between the two cavities of the differential cylinder without auxiliary components. Based on this principle, a new type of valve plate structure is designed by using the residual compression method. The pump performance is analyzed by PumpLinx simulation and experiment; the influence of the transition zone structure on the pressure and flow characteristics of the piston pump is researched. The basic characteristics of the pump such as pressure, flow, and noise under different working conditions were tested on the experimental platform, and the rationality of the new structure was verified. The new flow distribution scheme can not only compensate the flow difference of the differential cylinder, but also output two different pressures, which realizes the ideal effect of the hydraulic pump directly controlling the differential cylinder. The research work lays a theoretical foundation for the realization of the pump-controlled volumetric direct drive system.