车辆用内控可调速的液压优先阀设计

Design of hydraulic priority valve with internal control and adjustable speed for vehicles

摘要:

常规的液压优先阀在工作负载流量突变时,阀的动态响应存在一定的滞后现象,阀芯开启和关闭的响应速度均较慢,受限于保证压力稳定性和开启的响应速度在设计范围内,固定阻尼孔的设计尺寸较小,使得工况切换时,阀芯关闭速度慢,流经阻尼孔的补充油液流量小,无法满足系统快速补油的需求。为解决上述问题,在液压优先阀的主阀阀芯内部设计并集成了一个速度调节微阀,该微阀利用不同油液流动方向下阻尼孔不同的原理调节主阀的启闭响应速度,实现阀芯的缓开快关,根据阀内动力学方程,利用仿真对设计的微阀进行建模和优化,确定了最佳匹配参数并初步证明了设计的有效性。实验结果表明:通过合理匹配阻尼孔过流面积,当转向或换挡回路急需大流量时,速度调节微阀能够加快主阀的关闭速度,及时将辅路油液补充到主路,集成微阀相比传统主阀芯采用固定阻尼孔时的关闭速度提升了1倍；当转向或换挡完成后,速度调节阀能够实现主阀的开启速度比关闭速度慢,抑制压力冲击。速度调节微阀的设计解决了优先阀切换时主阀芯关闭速度慢的问题,有助于辅泵快速向主泵补油,满足系统工况改变的大流量需求,提升了系统的响应速度。

Abstract:

The dynamic response of conventional hydraulic priority valve will lag when there is a sudden change in load flow. The response of spools opening and closing is slow because it is limited by ensuring that the pressure stability and the opening response speed are within the designed range. Consequently, the size of the fixed orifice is small so that when working conditions are switched, the closing speed of valves is slow, resulting in a small flow of oil through the orifice, which cannot meet the needs of the system for rapid oil supplementation. In order to solve the above problems, we designed and integrated a speed regulating microvalve in the main spool of the hydraulic priority valve. This microvalve uses the principle of different orifices in different oil flow directions to adjust the opening and closing response speed of the main valve, and achieve slow opening and quick closing of the valve core. According to the dynamic equations of the valve, the designed microvalve is modeled and optimized by simulation. The best matching parameters are determined and the effectiveness of the design is demonstrated. The experimental results show that by reasonably matching the flow area of the fixed orifice, the microvalve can speed up the closing speed of the main valve and replenish the auxiliary circuit oil to the main circuit in a timely manner. Moreover, compared with the traditional main spool with fixed orifice, the closing speed of the microvalve is doubled. When the steering or shifting operation is completed, the speed regulating microvalve can realize that the opening speed of the main valve is slower than the closing speed and reduce the impact of the pressure. This design solves the problem of slow closing speed of the main valve core when switching the priority valve. In addition, it helps the auxiliary pump to quickly supply oil to the main pump and meet large flow demands under different working conditions as well as improve the response speed of the system.