The Analysis Of Efficiency In Hydraulic Motor-Vane Pump

The hydraulic motor pump is a new generation of hyaulic power unit.Compared with the traditional hydraulic power unit "three segment" which consists of hydraulic pump, coupling and electric motor in serial, the hydraulic motor pump have many important advantages such as very compact, very low noise, no exterior leakage and higher efficiency, so the hydraulic motor pump has many more applications. A new design which called the hydraulic motor-vane pump is put forward. The electric motor and vane pump are combined as a whole which do not need shaft coupling. The vane pump is skillfully integrated into the rotor of a special electric motor. So the volume of hydraulic motor vane pump is about 1/3 of that of traditional hydraulic power unit. The fan for cooling in the motor is ommited; oil flow is directed into channel of the motor to cool the motor pump. An auxiliary centrifugal pump is set in front of the suction port in vane pump to improve the suction performance. So the noise of the motor pump can decrease deeply.The thesis is mainly concerned on the analysis of efficiency in hydraulic motor-vane pump (called HMVP). The power losses of HMVP consist of the loss in motor, loss in vane pump, loss of oil flow in channel, oil film loss in motor and loss in the auxiliary centrifugal pump. Based the theritical analysis, electromagnetic field simulation and CFD, the efficiency of HMVP is 63.77% which is about 1.5% higher than that of the traditional hydraulic power unit. The effects of structure in auxiliary centrifugal pump on the suction performance of vane pump and power loss is clarified.In chapter 1, the importance of the hydraulic motor-vane pump has described and the development on hydraulic motor pump all over the world has introduced. The importance of improving the efficiency of the hydraulic motor-vane pump are analyzed and concluded. The research contents and significance are described. In chapter 2, the mechanism of power loss in hydraulic motor-vane pump is analysed. The power losses have five mainly parts: the loss of motor,loss of vane pump, loss of oil flow in channel, oil film loss in motor and loss in the auxiliary centrifugal pump. The reasons and the solutions which cause the losses are discussed. Baed on the motor fundamental theories, the cause of various losses in special motor is analyzed. It is shown that adopting the sinusoidal windings in stator of motor can help to improve the efficiency of special motor of the motor-vane pump. The calculation model of the oil film loss is presented.In chapter 3, the transient characteristics of motors are simulated by using Ansoft Maxwell 2D which is a sort of special software for the finite element analysis of electromagnetic field. The distribution of the magnetic field, the curve of thrust, flux density and power loss of a certain time when the motor is running are abtained. The influence of the hydraulic oil on the performance of the motor is analyzed by compared with the common three-phase induction motor.In chapter 4, the flow fields in 12 types of auxiliary centrifugal pump models are analysed using the FLUNT code, the structure of the auxiliary centrifugal pump is optimized. The main parameters of the pump influencing on the suction performance have been clarified, and the design criteria of the auxiliary centrifugal pump is obtained. The rotate centrifugal force of the auxiliary centrifugal can improve the suction performance and the efficiency of the vane pump.In chapter 5, the efficiency of hydraulic motor-vane pump is estimated. The efficiency of HMVP is 63.77% which is 14% higher than that of the traditional hydraulic power unit.