Abstract: The brake pedal feeling is the key indicator of the driver's subjective perception of a car, and a good pedal feeling can improve the driver's driving comfort. In this paper, combined with the problem of low braking confidence of drivers due to the soft brake pedal and long braking stroke of a commercial vehicle, the factors affecting the pedal feeling of the vacuum-assisted hydraulic braking system are analyzed. On the basis of theoretical calculations, the parameters of the key components of the commercial vehicle braking system are changed and optimized in combination with the actual situation. The relationship between pedal stroke, pedal force and braking deceleration of the original scheme and the optimized scheme is verified by the test. The test verification proves that the optimization scheme can effectively improve the pedal feeling, and the loading effect of the scheme is validated by the subjective feelings of the driver and the customer. It provides reference for the adjustment of brake pedal sense for commercial vehicles with the same braking form.

Key words: pedal feeling; vacuum booster; braking efficiency factor; pedal ratio

摘要： 制动踏板感是驾驶员主观感受一台车的关键指标，良好的踏板感受能提升驾驶员的驾 驶舒适性。文章结合某商用车因制动踏板软、制动行程长而导致的驾驶员制动信心不足问题， 分析了影响真空助力液压制动系统踏板感的因素。在理论计算基础上结合实际情况对该商用 车制动系统的关键零部件参数进行变更优化，并通过测试对比原方案和优化方案的踏板行程、 踏板力和制动减速度的关系进行验证。试验结果表明，优化方案可有效提升踏板感受，且该 方案的装车效果得到了驾驶员主观评价的认可，为相同制动形式的商用车制动踏板感调校提 供参考。

关键词: 制动踏板感；真空助力器；制动器效能因数；杠杆比