中文摘要：

在商用车制动时的方向稳定性分析中,前轮先于后轮抱死是一种稳定工况.理论分析了液力缓速器作用时对商用车前后桥制动力分配及同步附着系数的影响.研究发现,液力缓速器参与制动时最多存在两个同步附着系数,若要保证始终前轮先抱死,要求车辆实际行驶道路附着系数在两同步附着系数之间.而同步附着系数的大小与制动初速度和液力缓速器档位等影响液力缓速器制动力的因素有关.仿真结果表明,在不同附着系数的路面和不同制动速度下,合理选择液力缓速器档位使用可以减小商用车后轴侧滑的趋势,提高制动稳定性.

英文摘要：

In the analysis of commercial vehicle＇s brake stability, the situation of front wheels locked first is a stable condition. The influence on front＆back brake forces distribution and synchronizing adhesion coefficients when using hydraulic retarder is analyzed. It is pointed that, there exist two synchronizing adhesion coefficients at most. To ensure front wheels being locked first, the real traveling road adhesion coefficient must between the two coefficients. While the values of the coefficients depend on initial brake velocity and retarder gear, factors influenc the hydraulic brake forces. Simulation results show that selecting different hydraulic retarder gear levels at different ground adhesion coefficients can reduce the tendence of commercial vehicles ＇ rear axle sideslip and ensure brake stability.