Development of an asymmetric axial piston pump for displacement-controlled system

Abstract

Pump-controlled systems can eliminate throttling losses and improve the work efficiency of mobile hydraulic system. But one difficult problem for that is the differential volumetric flow through a single rod cylinder which is widely used in mobile hydraulic system. Several solutions have been presented to deal with it so far, but there still has not been a cost-effective solution to it. In recent years, an asymmetric pump-controlled asymmetric cylinder strategy has been presented to deal with this problem. In order to achieve this goal, an asymmetric axial piston pump with three ports was developed in this research. The flow rate ratio of the three ports of asymmetric axial piston pump was designed as 1: γ:(1 −  γ), in which γ was the area ratio of a single rod cylinder. An important task in the development of asymmetric axial piston pump was the design of the valve plate. There were three intake/discharge slots (slots A, B, and T) in the valve plate. The pumping dynamics of a fixed displacement asymmetric axial piston pump were investigated using software package ITI-SimulationX® and the performances of its prototype were tested. Simulation and experimental results show that with careful design, a V-shaped cross-section groove at the leading side of slot T can effectively improve the performance of asymmetric axial piston pump, and delivery pressure performance of port B is better than that of port T. Therefore, port T should be linked with low-pressure sources such as accumulator, and port B can be connected to high pressure sources. This work lays a theoretical foundation for a new exploration to pump-controlled system.