Abstract:
Abstract: Damping matching is the key problem of shock absorber design for leaf spring suspension system, and there is no optimal matching theory to resolve this problem at present, which seriously restricts the improvement of ride comfort and driving safety. So, in order to make the leaf spring suspension system achieve the optimal damping matching so that the vehicle has good ride comfort and driving safety, in this paper, based on the quarter vehicle model and random vibration theory, taking the minimum of body vertical vibration acceleration as the target, a mathematical model of optimal damping ratio of suspension based on ride comfort was established; taking the minimum of wheel dynamic load as the target, a mathematical model of optimal damping ratio of suspension based on driving safety was established; then, according to the golden section, a mathematical model of optimal damping ratio of suspension based on ride comfort and driving safety was built. Based on this, the root mean square value of suspension dynamic deflection was taken as the leaf spring vibration amplitude, which was obtained under actual road conditions for vehicle driving, and the root mean square value of suspension vibration velocity obtained under actual road conditions for vehicle driving was combined with the principle of energy conservation; by analyzing and processing the load and deformation array data of leaf spring loading-unloading test, the equivalent damping of leaf spring under certain work condition and the damping ratio provided by leaf spring for the suspension were built. Then, combining the optimal damping ratio of suspension based on ride comfort and driving safety with the damping ratio provided by leaf spring, using the displacement superposition principle, the optimal damping ratio, which should be provided by shock absorber matching to the optimal damping of leaf spring suspension, was built. Based on this, using the smoothness-safety ratio and the two-way ratio, a mathematics model of velocity characteristic of shock absorber matching to the optimal damping of leaf spring suspension was built. With a practical example, the optimal damping ratio and the velocity characteristic of shock absorber for leaf spring suspension system were designed, and the optimal damping matching method was validated by the simulation. The result showed that using the theoretical design method for the shock absorber, the root mean square value of body vertical vibration acceleration was reduced by 7.67% compared with the traditional experience method. Furthermore, in order to further verify the correctness of the result, the optimal damping matching method was validated by the vehicle ride comfort test. The result showed that using the theoretical design method for the shock absorber, the root mean square value of body vertical vibration acceleration was reduced by 6.72% compared with the traditional experience method. Therefore, the results showed that the optimal damping matching method of shock absorber for leaf spring suspension system was correct, and it could significantly improve the ride comfort of vehicle and make the vehicle have good driving safety. This study has significant value of theory research and practical application for shock absorber design of leaf spring suspension system.