The Influence Of Hydraulic Damper’s Structure Parameters On Its Performance

In order to guarantee the safety and stability, the train bogie must have a series of damping devices. Hydraulic damper is one of critical components that widely used in the suspension system, its performance makes great difference in train’s stability and comfort.Piston’s speed, oil’s temperature, inner flow passageway’s size and throttle valve’s opening condition are the key factors that influence damper’s performance. It’s easy to acquire damper’s external characteristic, while it’ll have some trouble to investigate the influence of the inner structure on its performance. So the method combining the external bench test and 3D simulation of damper’s inner flow is used to analyze its dynamic property, the main work including those:(1) Damper’s bench test:A group of damping characteristic curves vary with piston’s speed and oil’s temperature are acquired by analyzing damper’s dynamic property through experimental method. Therefore the effect of damper’s velocity and sticky temperature characteristic on its damping performance is obtained.(2) The 3d simulation model of damper’s flow field is established in order to simulate its dynamic process. Through the distribution of the inner flow field, the variation of oil’s pressure and flow velocity on the area of normal-open hole and throttle hole can be known.(3) Based on the experimental data, the damping characteristic curves in the conditions of different piston speed and oil temperature are obtained through 3D numerical simulation. Therefore analyze the influence of speed characteristics and temperature characteristics on damper’s damping characteristics.(4) The normal-open hole and throttle valve are the key factors to damper’s performance. The size of normal-open hole determines the slope of the curve before the valve opens. The opening process of throttle valve influences the trend of the curve after the valve opens. Through analyzing the influence of the hole’s size and valve opening condition on its performance, it can draw the conclusion:the amplitude of damping force will become larger as the hole’s size is smaller; it’ll cause a significant distortion if the valve moves too slow, while the damping force will fluctuate obviously if the valve moves too quick; valve’s maximum lift determines the amplitude of damping force.(5) Valve spring is the key component that control the movement of throttle valve. Spring’s stiffness and preload determine valve’s speed and opening time. Combining the calculation of flow field, calculate spring’s stiffness and preload through finite element analysis and analyze the connection between spring’s stiffness and throttle’s movement.