What is the main function of a synchronizer?

[BradleyLynn]

The main function of a synchronizer is to quickly synchronize the transmission engaging sleeve with the gear ring to be engaged, reducing gear shifting time and preventing gear shifting impact caused by engagement before synchronization, ensuring smoother driving. Synchronizers are divided into constant pressure type and inertia type. Currently, most synchronized transmissions use inertia synchronizers, which consist of an engaging sleeve, synchronizer lock ring, etc., and mainly rely on friction to achieve synchronization. The working principle of a synchronizer: When the inner conical surface of the synchronizer lock ring contacts the outer conical surface of the gear ring to be engaged, the gear speed rapidly decreases or increases to match the speed of the synchronizer lock ring under the action of frictional torque. Both rotate synchronously, and the relative speed of the gear to the synchronizer lock ring becomes zero, causing the inertia torque to disappear. At this point, under the action of force, the engaging sleeve smoothly engages with the gear ring of the synchronizer lock ring and further engages with the gear ring of the gear to be engaged, completing the gear shifting process.