The problem of stuck inner and outer rings of the bearing

Due to assembly requirements, there is an axial seam on the outer diameter of the TIMKEN bearing outer ring. After the sealing ring is installed, the axial seam of the outer ring will increase due to the amount of interference. When it is increased to a certain extent, it will cause the user's bearing installation difficulties, so the size of the outer ring gap should be strictly controlled, usually about 0.5mm is appropriate. For bearings with rib positioning, the interference between the rib of the seal ring and the seal groove of the outer ring should be appropriately reduced without affecting the assembly quality, so as to reduce the gap between the outer diameter of the outer ring.

The inner ring of the bearing is jammed. After the bearing is installed into the sealing ring, the inner ring cannot rotate flexibly or even cannot rotate. This phenomenon is called inner ring jam. The main method is to reduce the interference between the lip of the sealing ring and the spherical surface of the inner ring. That is, to increase the inner diameter d of the sealing ring, so that the contact between the lip of the sealing ring and the spherical surface is reduced. The second is to reduce the waist size e of the sealing ring to make the lips of the sealing ring more elastic and reduce the contact pressure between the sealing ring and the spherical surface of the inner ring. In addition, when designing the seal ring, the opening angle α should not be too large. As can be seen from the figure below, the opening angle gradually increases from α to β, and the straight line distance is from point A to point B. The contact area between the line BC and the inner ring is S1+S2 The contact area of ​​S2 is completely larger than the contact area S1 of the straight line AC and the inner ring. Under the same condition of the lip interference, the larger the area of ​​the seal ring contacting the inner ring spherical surface, the greater the bearing resistance to rotation and the easier it is to jam. At the same time, the lip of the sealing ring will be severely worn and cannot be used normally. Therefore, appropriately reducing the opening angle α can also increase the flexibility of bearing rotation. According to actual application verification, the opening angle α is generally about 45°.

The sealing ring inner lip bite back when the bearing rotates or flips, and the bearing exceeds its swing angle during rotation, and the sealing ring lip is involved in the inner spherical surface of the outer ring when resetting, which is called back bite of the sealing ring. For this phenomenon, the main solution is to reduce the amount of interference between the lip of the seal ring and the spherical surface of the inner ring; the second is to appropriately increase the rigidity and elasticity of the inner lip of the seal ring, that is, to increase the thickness of the lip part (see the figure below) Shaded part S) and reduce the waist size e of the sealing ring. Only if the lip of the sealing ring has sufficient rigidity and elasticity, the back bite will not occur when the bearing swings.