越野车用两级压力式油气弹簧的建模与仿真

两级压力式油气悬架可有效地解决传统单气室油气悬架在不同载荷状态下的动力学性能矛盾。为进一步提高越野车辆的行驶性能,提出一种越野车用两级压力式油气弹簧,建立考虑油液压缩性的油气弹簧非线性数学模型,并通过台架试验验证数学模型的准确性。建立1/4车辆模型,在随机路面激励下进行平顺性仿真。结果表明,良好路面的满载工况和一般路面的空载工况下,相对于单气室油气悬架,两级压力式油气悬架的车身加速度均方根值分别下降了20.1%和10.7%,轮胎动载荷均方根值分别下降了36.8%和10.4%,两级压力式油气悬架的动行程均方值分别增加了11.8%和1.9%,其撞击限位块的概率小于0.1%,能够满足车辆的使用要求。

Modeling and Simulating of a Two-Stage Pressure Hydro-pneumatic Spring for Off-Road Vehicle

In order to relieve the contradiction of dynamic performance between different loading conditions, a two-stage pressure hydro-pneumatic spring which is designed for off-load vehicle is proposed. Taking the compressibility of oil into consideration, a nonlinear mathematical model is established. A test bench for hydro-pneumatic spring is built and the accuracy of the model is verified. The one-quarter model of vehicle is built up to compare the simulations of vehicles equipped with single-accumulator hydro-pneumatic suspension to that with two-stage pressure hydro-pneumatic suspension under random road excitation. The results show that, compared with the former situation, the body acceleration root mean square (RMS) value under the latter condition decreases by 20.1% (paved road/full-load) and 10.7% (off-road/empty-load) respectively, and the tire dynamic load decreases by 36.8% and 10.4% respectively. Although the RMS value of dynamic travel of suspension increases by 11.8% and 1.9%, the probability of collision to set blocks is less than 0.1%, remaining in a reasonable range.