汽车驾驶室内的车速表是指示汽车行驶速度的仪表.它是利用电磁感应原理,使表盘上指针的摆角与汽车的行驶速度成正比.车速表主要由暑区动轴、磁铁、速度盘,弹簧游丝、指针轴、指针组成.其中永久磁铁与驱动轴相连。在表亮上装有刻度为公里/小时的表盘. The speedometer in the cab is a meter that indicates the speed of the car, which utilizes the principle of electromagnetic induction to make the swing angle of the pointer on the dial be proportional to the driving speed of the car.The speedometer is mainly composed of a summer moving shaft, a magnet, a speed plate, Spring hairspring, pointer axis, pointer composition, of which the permanent magnet and drive shaft connected. On the watch is a dial with a scale of kilometers per hour.