Research On Active Compensation For Axial Clearance In Internal Gear Pumps

Internal gear pumps have a broad prospect with the advantages of compact structures, light weight, small dimension, long operating life, low noise and low flow pulsation.The axial clearance leakage is the main factor affecting the volumetric efficiency of internal gear pump, and the floating plate is the key component that realizes the active compensation for axial clearance. In this paper, the back-pressure chamber, holes and damping grooves on floating plates and the axial clearance of the pump are analyzed and optimized, which provides reference to improve the efficiency and operating life of internal gear pumps. The main contents of each chapter are summarized as follows:In chapter 1, the advantages and development prospect of internal gear pumps are briefly introduced. The development of internal gear pumps technologies and fundamental researches home and abroad are summarized. The content and purpose of the research are proposed.In chapter 2, the operation principles of active compensating axial clearance are presented. The hydraulic force and moment acting on floating plate are obtained, which are periodically changing with gear rotation. The parameters of the back-pressure chamber are optimized using SQP method.In chapter 3, the functions of holes on floating plates are introduced, the radical hydraulic force acting on gears are obtained, which are periodically changing with gear rotation. The functions of damping grooves on floating plates are also analyzed, and the pre-loading mathematics model of damping grooves with different structures is built. The parameters of damping grooves are optimized.In chapter 4, the mathematics model for selecting optimum axial clearance is built. The axial flow field is simulated. The deformation of gears and floating plates are obtained with fluid-solid coupling method. The value of axial clearance considering the influence of deformation is got.The assembly axial clearance tolerance considering the influence of dimensional and geometric tolerance is gained using Jacobian-torsor method.In chapter 5, the test principles are introduced, and prototype pumps are tested. The experimental results indicate that pumps satisfy the use requirements. The surface of floating plates have no obvious abrasion after the test.In chapter 6, the content of the paper is summarized and future work is put forward.