ZF view on future drivetrains for compact and medium size wheel loaders

This paper discusses an investigation on a novel hydraulic pump concept. The idea aims on a pump principle to be directly connected to highspeed electric motors to build compact highpressure drives. The pump can theoretically work without solid contact and has no kinematic pulsation. The composition of the pump is basically similar to cylindrical journal bearings. A journal bearing is used to support external loads on a rotating shaft. When the shaft rotates with the loads, hydrodynamic fluid force is generated in the fluid film, which compensates the external force and reduces an eccentricity of the shaft. The difference of the introduced pump concept from the bearing is that the eccentricity is fixed and it has an outlet port at the highpressure area, through which the fluid can be transferred. To examine the functionality of the pump, a test bench is constructed and experiments are performed to investigate the pressure build-up and discharging flow of the pump concept. The experimental results are numerically analysed by using elastohydrodynamic lubrication (EHL) simulation,