载重汽车在行驶或停车时,在许多情况下需要升起一个或几个轴,最主要的有如下情况: 在空载时升起从动轴以减少轮胎磨损; 救火车、超重车等特种车,在停车作业时需要在车轴和车身之间刚性连接。浮渡车的车轮如能升起,则在浮渡时能减少水的阻力; Truck driving or parking, in many cases need to raise one or several axes, the most important are as follows: In the no-load rise of the driven shaft to reduce tire wear; fire trucks, overweight vehicles and other special vehicles , In the parking operation need rigid connection between the axle and the body. Floating car wheels if they can rise, the float can reduce the water resistance;