拖拉机前桥油气弹簧的设计与特性研究

Design and characteristic study of tractor front axle hydro-pneumatic spring

[目的]为了提高我国拖拉机的乘坐舒适性和行驶平顺性,设计并研究了拖拉机前桥油气弹簧减振系统。[方法]以常发CF700型拖拉机为研究对象,建立前桥悬架拖拉机三自由度振动模型,根据拖拉机前桥悬架的参数要求,设计了刚度和阻尼均可调的油气弹簧系统,以此为基础建立油气弹簧刚度和阻尼的非线性数学模型,并计算了油气弹簧的结构参数。仿真研究了油气弹簧的性能,并对所设计的油气弹簧进行了静、动态特性试验。[结果]静态特性试验得到油气弹簧的刚度特性,其在平衡位置处的静刚度系数为72.6 kN·m^(-1);动态特性试验研究了比例阀电流、各节流阀开度及激振频率对油气弹簧输出力的影响规律,结果表明所研制的油气弹簧能够在较大范围内调节输出力的大小,满足前桥悬架的设计要求。[结论]该研究为后期开发前桥油气弹簧系统提供重要的理论依据。

[ Objectives ] In order to improve the tractor ride comfort and performance in our country, tractor front axle hydro-pneumatic spring was studied. [ Methods ] Taking the CF700 tractor as the research object, the vibration differential equation of tractor front axle suspension system was established, and the three degrees of freedom vibration model of front axle suspension tractor were built up. Based on the requirement of CF700 tractor front axle suspension parameter, hydro-pneumatic spring with controllable stiffness and damping was designed. The stiffness and damping nonlinear mathematical model of hydro-pneumatic spring was established and the structural parameters of hydro-pneumatic spring were calculated. The performance of the hydro-pneumatic springs was studied by simulation, and the static and dynamic characteristics of the hydro-pneumatic spring were researched by experiment. [ Results ] Stiff- ness characteristics of hydro-pneumatic spring was studied and the static stiffness of hydro-pneumatic spring in equilibrium position was 72.6 kN. m-1. The influence of proportional valve current size,the opening of the throttle valve size and excitation frequency to output force of hydro-pneumatic spring were studied by dynamic experiment. The results showed that the designed hydro-pneumatic spring can adjust output force on a wide range of sizes. [ Conclusions] The study provides important basis for the later development of the semi-active hydro-pneumatic suspension of tractor front axle suspension.