Synchronizers are classified into constant-pressure and inertia types:
Currently, all synchronized transmissions utilize inertia synchronizers, which are primarily composed of a sleeve, synchronizer ring, and other components. Their key feature is achieving synchronization through friction during the synchronization process. Both the sleeve, synchronizer ring, and the gear ring of the gear to be engaged all feature chamfers (locking angles). Friction is generated when the inner conical surface of the synchronizer ring contacts the outer conical surface of the gear ring of the gear to be engaged. The locking angle and conical surface are appropriately selected during design. The conical friction rapidly synchronizes the sleeve to be engaged with the gear ring, while also creating a locking action to prevent the gear from engaging before synchronization.
Once the inner conical surface of the synchronizer ring contacts the outer conical surface of the gear ring of the gear to be engaged, under the action of frictional torque, the gear speed rapidly decreases (or increases) to match the speed of the synchronizer ring. Both rotate synchronously, and the relative speed of the gear to the synchronizer ring becomes zero. Consequently, the inertial torque also disappears. At this point, driven by the applied force, the sleeve engages unimpeded with the synchronizer ring's gear teeth, and further engages with the gear ring of the gear to be engaged, completing the shifting process.
