作业选择A+B或C+D 汽车服务工程专业英语 教学课件.pptVIP

Translation A Drum brakes work on the same principle as disc brakes: Shoes press against a spinning surface. In this system, that surface is called a drum. In the drum-and-shoe type, there is a wheel brake cylinder with two pistons. When brake pedal is pushed by the driver, brake fluid is forced into the brake cylinder by the action at the master cylinder, and the two pistons are forced outward. This causes the curved brake shoes to move into contact with the brake drum. Translation B The propeller shaft transmits the drive from the gearbox mainshaft to the final drive pinion. The drive shaft is not solidly bolted to the gearbox and the final drive, which moves up and down with wheel-spring movement. Two separate actions are produced by this movement. First, the distance between the gearbox and the differential changes as the differential moves up and down. As the springs compress and the differential moves up, the distance increases. As the springs expand and the differential moves down, the distance decreases. Translation C In steering gear box the gear is slightly larger and has other parts. The wormshaft is the same in both systems. Instead of a ball nut, though, the power steering system uses a power piston or rack piston in steering gear box. The power piston has teeth on one side that mesh with the sector teeth. The forward and backward motion of the power piston moves the sector, pitman shaft, and steering linkage. The power steering gear also uses a control valve to send hydraulic fluid into the steering gear at the right time. pitman: 连接杆，转向臂; wormshaft:蜗杆轴 Translation D The main components that make up an automatic transmission includes: (1) Planetary Gear Sets, which are the mechanical systems that provide the various, forward gear ratios as well as reverse. (2) The hydraulic system, which controls the clutches and the bands in order to control the planetary gear, sets. (3) Seals, which are used to keep the oil where it is supposed to be and prevent it