have a braking action to control the braking effect and braking energy transmitted to the various brake components and wheel brake cylinder and brake lines.
产生制动动作、控制制动效果并将制动能量传输到制动器的各个部件以及制动轮缸和制动管路。
in the drum-and-shoe type, there is. a wheel brake cylinder with two pis. ons.