Characteristics of Various Losses of Axial Piston Pump and Bent Axis Hydro-motor with respect to Displacement Conditions and Load Demands

The hydrostatic transmission is one of the most important applications in the fluid power systems. It gives smooth change in output speed, torque and power as per the design requirements. Present article deals with various losses of the hydraulic pump and motor using a closed circuit hydraulic drive. The drive basically consists of a variable displacement axial piston pump that supplies pressurized fluid to a variable displacement bent axis hydro-motor. In investigating the pump/motor performance, bond graph simulation technique is used to model the drive system. Various losses of the pump and motor are accounted in the model by suitable resistive elements. The characteristics of them are identified through experiments. The predicted performance of the pump/motor is studied with respect to the displacement and load at the same time they are validated experimentally. The investigation made in the article identifies the control strategy which will be useful for the practicing engineers to select best combination of the pump and motor displacement for optimizing the drive performance and minimizing the losses as well. The study performed in this research work will be useful for the similar hydraulic configuration used in mobile equipment.