Viscous Load Effects Within Air-gap In Hydraulic Motor-Vane Pump And Performance Test Of A Prototype

A novel design of hydraulic motor pump (HMP) is proposed which the heart of vane pump is integrated in the internal of the rotor of electric motor. HMP has many advantages such as the compact in dimension, lower noise, and no external leakage. It is an important development direction in hydraulic power unit at present.In the thesis, numerical simulation, experimental study and theoretical analysis are combined together to investigate the effect of viscous load and performance test for HMP. The energy transformation of HMP is established. The theoretical model of air-gap load torque of HMP is built. Many factors have influence on loaded torque with air-gap, such as radial of rotor, the size of air-gap, length of the stator core, speed of rotation and viscosity of oil. The first prototype of HMP is built up successfully in the country. Its performance test-bed is set up and experiments are carried out. The investigations show that there are two main reasons for large declining of volumetric efficiency of prototype by big margin under high pressure, one is failure of PTFE sealing, the other is large fit clearance and radial deformation on the seat of the heart of vane pump under high pressure. Low efficiency of electric motor is induced by the unreasonable manufacture of electric motor and viscous loss of oil.The main contents of the thesis:In chapter 1, the background and significance of this thesis is presented. The history and current research progress on hydraulic motor pump are reviewed. The application of the finite element method to investigate the electric motor is summarized. Lastly, the main research subjects are presented.In chapter 2, a new design of HMP is put forward, and its principle is presented. The energy transformation of HMP is set up.In chapter 3, according to the structure of HMP, the theoretical model of loaded torque with air-gap is proposed. The influence of radial of rotor, the size of air-gap , length of the stator core, speed of rotation and viscosity of oil on loaded torque with air-gap are analyzed.In chapter 4, the test method of the prototype of HMP and test devices are introduced. The sources of error in the experimental measurement are analyzed. The performance parameters of the prototype are analyzed such as the efficiency of of the prototype, output pressure, speed of rotation, and power factor varying with output power, etc. By calculating efficiency of the heart of vane pump and the deformation of the seat and PTFE, it concludes that the failure of PTFE sealing, large fit clearance and radial deformation on the seat of the heart of vane pump under high pressure can lead to decreasing volume efficiency.