When roller type one way clutch works, the maximum contact stress occurs at the contact between roller and inner and outer ring. Strictly speaking, because the forces on both sides of the roller are equal, and its contact area with the convex surface of the inner ring is smaller than the contact area with the concave surface of the outer ring, so the maximum contact stress occurs on the contact surface of the roller and the inner ring. Here, surface fatigue wear is the most likely to occur, the typical failure form is pitting peeling. Metal materials for making one way clutch rollers and inner and outer rings are generally the same as rolling bearing materials.
Because when the clutch one way bearing works, the roller is always affected by the rotating centrifugal force, so it always tries to deviate outward from the contact point with the periphery. Therefore, the roller must be pressed to the small end of the opening groove with the help of a spring to stop this deviation, which is why the spring should be required to have a certain pre-tightening force.