One-way clutch is to lock a certain working part so that it can only rotate in one direction. In layman's terms, when a bicycle is walking forward, the wheels will move forward, but the wheels will not move backward when moving backward, which is equivalent to the working principle of a one-way clutch. 

One-way clutches can be divided into two types: wedge type and ball type. The wedge block type is composed of multiple wedge blocks and a fixed bracket. Since the shape of the wedge block is rhombus, if the outer edge of the one-way clutch is fixed during operation, the inner edge of the one-way clutch can only rotate clockwise at this time. When rotating counterclockwise, the wedge block connects the inside and the outside as a whole, so the inner edge is also fixed. When the inner edge of the one-way clutch is fixed, the outer edge of the one-way clutch can only rotate counterclockwise at this time. The ball type consists of multiple balls and a return spring. When working, the outer edge is fixed, and the inner edge is connected to the outer edge by the ball when it rotates clockwise, and the fixation is locked. When rotating counterclockwise, the steel ball is driven to overcome the elastic force of the spring to reverse, so that the gap between the steel ball and the inner edge is increased, and the inner edge can freely rotate counterclockwise. On the contrary, when the inner edge is fixed, it is locked and cannot be operated.