The power train consists of two main parts: transmission and drive axle. Transmission includes Automatic-transmission and Manual-transmission. The function of a transmission is to transfer engine power to the drive axle. Gears inside the transmission change the car‟s drive-wheel speed and torque in relation to engine speed and torque. This keep the engine‟s output matched as close as possible to varying road speeds and loads. Drive axle is at the end of the power train, it consists of: main reduction gear, differential, drive shaft. Its basic function is increasing the torque and reducing the speed, bearing the force between the road and the frames or body.
Its performance will have a direct impact on vehicle‟s performance, in particular new type of Moto-tricycle. Because a tricycle using the big power engine with the high speed and not affect its characteristic of high efficiency and high driving, must exploiting the high driven efficiency single reduction final drive axle is becoming the Moto-tricycle‟s developing tendency.
Drive axle should be designed to ensure the best dynamic and fuel economy on given condition. According to the design parameters given, firstly determine the overall vehicle parameters in accordance with the traditional design methods and reference vehicle‟s parameters, then identify the main reducer, differential, axle and axle housing structure type, finally design the parameters of the main gear, the driven gear of the final drive, axle gears and spiral bevel gear and check the strength and life of them.
In design process of the drive axle, we should ensure a reasonable structure, practical applications, and the design of assembly and parts as much as possible meeting requirements of the standardization of parts, components and products‟ universality and serialization and change. And convenience of repair and maintenance also is benefit to new type of Moto-tricycle‟s generalization.
Key words: Moto-tricycle, drive axle, transmission, single reduction final drive