汽车液压助力转向器手力转向单向阀设计

Design of Hand Steering Check Valve for Automotive Hydraulic Power Steering Gear

【目的】动力转向系统依靠液压助力实现转向,当转向油泵出现故障时,转向系统失去助力,必须依靠手力进行转向,但此时回油路阻尼较大,造成手力转向困难,增加了行车风险。为了使转向器在转向油泵失效时仍具有机械转向的能力,需要设计一种动力转向器手力转向单向阀。【方法】课题组在分析了动力转向器工作原理和内部结构后,提出了在转向器内部使用单向阀构成液压小循环回路的解决方案,并结合图示详细说明了总体设计思路和基于单向阀的小循环回路设计方法。【结果】在动力转向器阀体进油道与回油道之间增设手力转向单向阀,正常工作状态下,液压系统进油路压力远大于回油路压力,单向阀在压力差作用下可靠地实现密封;在液压回路出现故障时,进油路因失去助力而压力降低,而回油路压力将异常增大,在压力差的作用下,单向阀及时开启,将进油道与回油道导通,以减小回油路阻尼,实现手力转向,保障了行车安全。

[Objective]The power steering system relies on hydraulic power to realize steering.When the steering oil pump fails,the steering system loses power and must rely on manual power for steering.However,at this time,the damping of the return oil circuit is large,causing difficulty in hand steering and increasing driving risks.In order to ensure that the steering gear still has the ability to mechanically turn when the steering oil pump fails,it is necessary to design a hand steering check valve for automotive hydraulic power steering gear.[Method]After analyzing the working principle and internal structure of the power steering gear,the research group proposed a solution to use the check valve to form the hydraulic small circulation circuit inside the steering gear.The overall design idea and the design method of the small circulation circuit based on the check valve were explained in detail with the diagram.[Result]The hand steering check valve is added between the inlet and return oil passages of the power steering gear valve body.Under normal working conditions,the inlet pressure of the hydraulic system is much greater than the return pressure,and the check valve reliably achieves sealing under the pressure difference.When the hydraulic circuit malfunctions,the pressure in the inlet oil circuit decreases due to the loss of power,while the pressure in the return oil circuit will abnormally increase.Under the pressure difference,the check valve opens in a timely manner,connecting the inlet and return oil channels to reduce the damping of the return oil circuit,achieving hand steering,and ensuring the safety of the vehicle.