Abstract: A new kind of cam-rotor vane motor is introduced with its working principles and features. Motor’s leakage models are established based on the clearance flow model between parallel flats and parallel plates. Therefore, the relationship between motor’s liquid film thickness and volumetric efficiency is obtained. The relationship between motor’s thickness of liquid film and mechanical efficiency is obtained by the analysis and calculation of the friction torque between motor’s two critical friction pairs based on the absolute viscosity model. Based on analysis on the motor of a three-axis non-magnetic turntable system, the optimal liquid film thickness leading to motor’s maximum total efficiency is obtained by synthesizing the effect of volumetric efficiency and mechanical efficiency. The significance of the study is to provide the theoretical basis for the subsequent optimization of liquid film thickness of vane motor’s critical friction pairs. Furthermore, the dimensional precision, geometric precision and surface roughness of the key components such as cam rotor, stator and clapboard can be put forward in the process of design and manufacture of cam-rotor vane motor.

Key words: cam-rotor vane motor, liquid film thickness, leakage model, volumetric efficiency