When running, the motor drive, through the crank-connecting rod of the role of the (rotation movement into linear movement), so that the piston within the cylinder for reciprocating motion.

• 运转时，在电动机的驱动下，通过曲柄连杆机构的作用（旋转运动转变成直线运动），使气缸内的活塞作往复运动。