刚度和阻尼可调前桥油气悬架的设计

根据CF700型号拖拉机前桥悬架的参数要求,设计一种刚度和阻尼均可调的油气悬架系统。建立油气悬架刚度和阻尼的数学模型,计算油气弹簧的结构参数,仿真研究油气弹簧不同工作状态下的动刚度、阻尼力和输出力的特性以及各结构参数变化对油气弹簧输出力特性的影响。结果表明:油气弹簧液压缸有杆腔和无杆腔连通时阻尼力和悬架输出力较小,两腔分离时阻尼力和悬架输出力较大,通过调节两腔连通时节流面积的大小,可以调节悬架阻尼力和输出力;通过额外连通一个蓄能器,明显减小了油气弹簧的动刚度和悬架的输出力;比例阀节流孔径的大小影响悬架的阻尼力和输出力,节流孔径越大,悬架阻尼力和输出力越小。所设计的油气弹簧可以实现悬架"软"、"硬"状态的切换,并能在一定范围内对悬架刚度和阻尼进行调节。将油气悬架的刚度和阻尼系数线性化后代入振动仿真模型,得到前桥悬架拖拉机座椅安装位置垂向振动加速度均方根值、俯仰振动角加速度均方根值及前轮动载荷均方根值分别降低了9.2%、42.4%、70.3%,提高了拖拉机的行驶安全性和乘坐舒适性。该研究为后期开发半主动油气悬架提供重要理论依据。

Design of a Front Alxe Hydro pneumatic Suspension with Controllable Stiffness and Damping

Based on the requirement of CF700 tractor front axle suspension parameter, a hydro-pneumatic suspension with con trollable stiffness and damping was designed. The stiffness and damping mathematical model of hydro-pneumatic suspension was estab lished and the structural parameters were calculated. Characteristics of the dynamic stiffness, damping force and output force under various work conditions of hydro-pneumatic suspension and the influences of the structural parameters on suspension output force were simulated. The results show that when rod cavity and rodless cavity of hydro-pneumatic spring cylinder connects, the damping force and suspension output force are smaller than two separated oil cavities. By adjusting the throttling area when two oil cavities connect can adjust the suspension damping force and output force. By additional connecting an accumulator, the dynamic stiffness and output force of the hydro-pneumaticspring are significantly reduced. The throttle aperture size of proportional valve affects the suspension damping force and output force, the greater the throttle aperture, the smaller the suspension damping force and the output force. The designed hydro-pneumatic spring can realize the "soft" and 'harcl' state switch of suspension stiffness and damping, and the stiffness and damp ing are available to be controlled at a certain range. Bringing the linearization of stiffness and damping coefficients of front axle suspen sions to the vibration simulation model, it is shown that the RMS of seat position vertical vibration acceleration, the RMS of seat posi tion pitch angle vibration acceleration and the front tire dynamic load of tractor with front axle suspension are respectively reduced by 9.2%、42.4% and 70.3%. The tractor driving safety and ride comfort are improved. The study provides important basis for the later development of the semi-active hydro-pneumatic suspension.