1. The impact between the rotating key and the middle sleeve, that is, the collision between the two during the joint process of the steady state rotating key and the rotating middle sleeve.
2. The impact between the rotary key and the crankshaft, that is, when one side of the rotary key collides with the middle sleeve, the other side collides with the crankshaft under the action of the former reaction force.
3. The impact between the crankshaft and the sliding bearing it supports.
The magnitude of the impulse received when the clutch is engaged determines the impact speed under the condition of a certain quality; it is also related to the stiffness and damping characteristics of the contact material itself.