Research On Vehicle's Variable Damper

Vehicle suspension system plays an extremely important role in improving vehicle ride comfort and handling stability. It is to pass the vertical force, longitudinal force and lateral force imposed on the tires from the road and the torque resulted from the force to the vehicle frame in order to ensure the vehicle's normal driving.The vehicle suspension is classified as the passive suspension, semi-active suspension and active suspension. The passive suspension is a compromise between ride comfort and handling stability, because the spring and the damper are not controllable. The active suspension removes the restrictions of the passive suspension; there are few actual active suspension systems on vehicles because of the high cost. While the semi-active suspension's performance is not as good as active suspension systems, it receives much attention from many manufactures of vehicles because of its low cost and simple control simppicity. As part of mordern vehicle suspension, the damper is an important part to absorb the shock from the spring and improve ride comfort. The semi-active suspension in the paper changes the parameter of the suspension by changing the parameter of the damper, adjusting the damping force among several states. The structure design and characteristic test of this kind of semi-active suspension were carried on in this thesis.First, the theory about large limited deflection of thin elastic annular plate was applied to the damping valves of the dampers, where the deformance of valve plates was taken as thin-wall ostiole throttling. According to the principle of Hydromechanics, the damping property of the dampers was analyzed, which gave the design of the damper an excellent guide.On the basis of MC Pherson damper, a kind of semi-active variable damper was conceived, a method was put forward which changes the damping by turning a throttle scoop. A manual variable damper and an automatic variable damper were developed by this way.The manual variable damper and the automatic variable damper were tested according to corresponding national standard, and speed characteristic curve & damping characteristic curve obtained by bench test. The dynamic characteristics of the variable damper were analyzed and the conceived dampers were validated provided reliable gist for constituting more applicable model for semi-active suspension.