Transmission is made of two parts that variable speed drive mechanism and variable speed operation mechanism, can be made into a separate variable speed mechanism or and drive mechanism in the same casing. Variable speed drive mechanism main function is to change the numerical value and direction of torque and rotational speed; Operation mechanism main function is to control the drive mechanism, realize transmission velocity ratio of transformation, namely the realization of shift.
Transmission mechanism mostly uses the ordinary gear drive, also uses planetary gear transmission. Ordinary gear shifting mechanism uses slip gear and clutch. Slip gear has multi-slip gear and dislocation slip gear. Use multi-slip gear variable speed, axial dimension is big; use dislocation slip gear variable speed, compact structure, but the transmission ratio changes little. Clutch has mesh type and friction type. Use mesh type clutch, variable speed should go ahead in park or rotational speed difference is very small. Use friction clutch can be variable speed under any speed difference in operation, but the capacity is small, and can not guarantee two shafts strictly synchronous. At the mesh type clutch installs friction plate, when variable speed first by friction plate driven wheel after to the synchronous speed then to joint. As a result, can overcome shortcoming of two shafts can’t synchronic.
Simple transmission has efficiency high, simple structure, use convenient, etc. advantages; but gear number less, variation range is small, only appropriate in certain gear number is not much use in the car. If the increase scope, makes the transmission size increases, shaft span increases. If use integrated transmission, can increase the gear number and don’t make shaft span is too large.