湿喷机液压制动系统制动阀性能研究

为了研究串联式双回路液压制动阀对湿喷机制动性能的影响，根据制动阀结构及工作原理，考虑稳态液动力等非线性因素，采用键合图理论建立了液压制动系统的动力学模型，基于MATLAB平台仿真分析了制动阀的静、动态特性，并在湿喷机上搭建实验平台进行其制动性能测试。结果表明：制动阀输出压力具有比例特性，后桥制动响应快于前桥，且后桥制动压力约大于前桥制动压力0.2 MPa；制动阀双段制动压力梯度的设计可以满足湿喷机在高低速行驶时动能差别较大的制动需求；制动阀阶跃响应迅速，系统能在0.3 s内趋于稳定，且无明显压力超调，制动性能稳定；在制动阀复位阶段，制动油缸将工作腔油液迅速排入油箱，解除制动。制动压力的测试值与仿真值基本吻合，验证了所建模型的准确性。研究结果可以为制动系统的参数匹配和制动阀结构优化提供参考。

Study on brake valve performance of hydraulic brake system of wet spraying machine

In order to study the influence of the series double circuit hydraulic brake valve on the braking performance of the wet spraying machine, according to the structure and working principle of the brake valve, taking into account the nonlinear factors such as the steady-state hydrodynamic force, the dynamic model of the hydraulic braking system was established using the bond graph theory. Based on the MATLAB platform, the static and dynamic characteristics of the brake valve were simulated and analyzed, and an experimental platform was built on the wet spraying machine to test its braking performance. The results showed that the output pressure of the brake valve had a proportional characteristic, the brake response of the rear axle was faster than that of the front axle, and the brake pressure of the rear axle was about 0.2 MPa higher than that of the front axle; the design of two-stage braking pressure gradient of the brake valve could meet the braking demand of the wet spraying machine with large kinetic energy difference at high and low speeds; the step response of the brake valve was rapid, the system could become stable within 0.3 s, without obvious pressure overshoot, and the braking performance was stable; in the reset phase of the brake valve, the brake cylinder quickly discharged the oil in the working chamber into the oil tank to release the brake. The test value of brake pressure was basically consistent with the simulation value, which verified the accuracy of the model. The research results can provide reference for parameter matching of braking system and optimization of brake valve structure.