The Impact of Dead Chamber on the Pressure Characteristics of High Flow Piston Pump and Its Potential Hazards

Focusing on the internal pressure characteristics and potential hazards of the cylinder bore from a high pressure, variable displacement axial piston pump, this work investigates the impact of the dead chamber surrounded by the piston and cylinder bore on the pump. We have verified through two methods, CFD numerical method and durability test, that having a larger closed dead chamber can can increase the pressure fluctuation and noise of a large displacement heavy-duty pump, reduce volumetric efficiency. Additionally, numerical calculations show that when there is a larger dead chamber working condition, the internal flow of the piston hole in the low-pressure absorbing stroke will generate a significant impact inertia of medium pressure, which is consistent with the location of cavitation erosion generated in the low-pressure zone of the swash plate in the durability test. On the contrary, using a slender hole piston with a closed cavity can effectively alleviate or even avoid the occurrence of these malignant problems.