Effects of materials on the tribological properties and the noise of gerotor pump used in active vibration damping system

An automobile active vibration damping system is mainly consists of a pump-controlled cylinder system with highly responsive, small volume and lightweight, the performance of the friction pair of the hydraulic pump puts forward high requirements. A compact and lightweight gerotor pump was designed, and the characteristics of the friction pair and the noise of the rotor and valve plate materials were investigated in this study. Tribological experiments were conducted on different materials with and without surface microtexture distribution pair. Results show that the steady-state average friction coefficients of Poly-Ether-Ether-Ketone (PEEK) without and with microtexture surface are 0.059 and 0.044, respectively, and the friction coefficient reduces by 25.4%. Lead bronze without and with microtexture surface are 0.137 and 0.103, the friction coefficient reduces by approximately 24.8%. Inner and outer rotor noise experiments show that different materials have different effects on reducing the noise at different speeds. The gerotor pump noise ranges from high to low in the order: 9Cr18/9Cr18>9Cr18/PEEK>PEEK/PEEK. The active vibration damping system gerotor pump using PEEK can reduce the noise, compared with the inner and outer rotors using 9Cr18, the noise of gerotor pump only inner rotor uses PEEK is reduced by 2.78% and 0.78% at 1000 rpm and 5000 rpm, both of rotors uses PEEK can reduce the noise 4.5% and 2.57% at the rotation speed is 1000 rpm and 5000 rpm. The flow characteristics of the gerotor pump with PEEK rotors are studied at the end of the article, as the rotation speed increases, the volumetric efficiency of the pump decreases. Therefore, the selection and surface treatment of these materials are suitable for the active vibration damping system gerotor pump.