The tie rod is one of the key components affecting the steering stability and reliability in the steering system of heavy vehicles. In order to meet the heavy load steering requirements of heavy vehicles, the steering system is universally the electro-hydraulic power steering system (EHPSS). The hydraulic actuators used in the EHPSS are double hydraulic cylinders, which are connected in series and symmetrically installed in this study. The hydraulic drive system in the steering system will affect the steering mechanism of stress state, leading to the tension of the tie rod in most working conditions. The tie rod be compressed only in extremely unequal loading of dual-tires. The tie rod force model is established based on Lagrange equation and verified by the tie rod test platform. Three key parameters describing the force rule of tie rod are obtained by adopting quasi-steady state analysis method, including pump pressure, difference value and sum value of left and right tires steering resistance torque. Pump pressure is the key factor affecting the tie rod force. The higher the pump pressure is, the greater the pull force of tie rod is. The steering resistance torque will further affect the variation law of the tie rod force. In the analysis when the tire at middle position, with the increase of difference value of steering resistance torque, the tie rod force offset between loading conditions and no-load conditions increases. When the tire turns from the middle to both sides, the increase of sum value of steering resistance torque will result in the rising of tie rod force change rate. This study reveals the variation law and key parameters of the tie rod force of heavy vehicles. It can provide basis for stability and reliability design of steering system.

中文翻译：

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重型汽车电液助力转向系统拉杆受力特性研究

拉杆是重型车辆转向系统中影响转向稳定性和可靠性的关键部件之一。为了满足重型车辆的重载转向要求，转向系统普遍采用电液动力转向系统（EHPSS）。EHPSS 中使用的液压执行器是双液压缸，在本研究中串联并对称安装。转向系统中的液压驱动系统会影响转向机构的受力状态，在大多数工况下导致拉杆拉紧。只有在双轮胎负载极不均匀的情况下才能压缩拉杆。基于拉格朗日方程建立拉杆力模型，并通过拉杆试验平台进行验证。采用准稳态分析方法得到描述拉杆受力规律的三个关键参数，包括泵压、左右轮胎转向阻力矩差值和总和值。泵压是影响拉杆力的关键因素。泵压越高，拉杆的拉力越大。转向阻力矩会进一步影响拉杆力的变化规律。在轮胎处于中间位置时的分析中，随着转向阻力矩差值的增大，加载工况和空载工况之间的拉杆力偏移量增大。当轮胎从中间转向两侧时，转向阻力矩和值的增加会导致拉杆力变化率的增加。本研究揭示了重型车辆拉杆力的变化规律和关键参数。可为转向系统的稳定性和可靠性设计提供依据。