If the pillar rivet is bent and deformed due to instability under the action of the riveting pressure, it will also cause the cage to clamp the ball and the bearing to rotate inflexibly. Because the rivet has a large bending flexibility in the thickness direction, it is only necessary to check the stability of the rivet in the thickness direction. The flexibility of ring-grooved rivets in the thickness direction where the cost is small is as follows: λ is the flexibility, μ is the height coefficient, i is the radius of inertia, and J is the moment of inertia of the rivet in the thickness direction.
When the rivet is riveted again, it can be regarded as its lower end fixed, and the upper end can only translate and not rotate. Because the rivet is short, its flexibility is generally less than the flexibility of the corresponding material limit, so the rivet is a small flexibility rod, so the critical stress of rivet instability is the formula for checking the stability of the rivet.
In the formula: is the actual stability safety factor when the rivet is riveted, and is the specified stability safety factor, generally 1.8-3.0, the working stress of the rivet. If the calculation result of the ring groove rivet does not meet the above conditions, it indicates that the stability of the rivet is insufficient during riveting, and the rivet thickness S should be increased to improve its stability.
During riveting, it is easy to cause problems such as rivet deformation and misalignment of the two cage halves. Therefore, when designing the ring groove rivet, the rivet and cage parameters should be selected reasonably, and relevant checking calculations should be performed to avoid the phenomenon of bearing ball clamping and inflexible rotation.