1. Vibration caused by bearing manufacturing errors

The inner and outer ring raceways and rolling element surfaces of rolling bearings have different degrees of wavy machining marks - waviness in the circumferential direction. This is an extremely important factor that causes bearing vibration, induced noise and eccentric movement of the axis of the rotating shaft. Vibration caused by the waviness formed by the machining marks also occurs in bearings without radial clearance or when an axial load is applied to bearings other than ball bearings. In addition, there are many wave numbers of raceway waviness. bearing, also occurs when a radial load is applied.

The above-mentioned bearing rolling surface waviness caused by manufacturing factors can only be solved by improving the machining accuracy of the rolling surface and reducing the shape of the raceway surface if it is to control its influence on the bearing vibration. In terms of modern technology, this technology has made progress, but it cannot completely eliminate the impact of this wave pattern on the noise of the bearing station.

And it should be noted that not only the manufacturing factors of the bearing, but also the mounting factors of the bearing and the rigid conditions of the shaft and the bearing seat may cause the waviness of the raceway surface of the bearing, and their influence is often greater than that of the manufacturing factors. It is a problem that bearing users must solve.

2. The influence of the shape and position accuracy of the shaft and the seat hole

The shape and position accuracy of the shaft and seat hole is poor, and the ring of the bearing will be deflected and deformed after the bearing is installed, and the low-frequency vibration caused by this is larger than the vibration caused by the inherent waviness of the bearing rolling surface.

(1) The influence of the non-perpendicular effect of the ferrule and the positioning shoulder

When the bearing ring is not perpendicular to the positioning shoulder of the mounting position, if it is a dynamic fit in the circumferential direction, the ring will be twisted, the raceway will become elliptical, and the roundness error is about the gap between the ring and the mounting surface. twice.

(2) Influence of geometric error of installation surface

The roundness of the bearing ring raceway is generally about 2μm. If the shape error of the mounting surface is greater than 2μm, usually it has a waviness of 2 to 10 waves. When the bearing ring is installed on this surface with an interference fit, its raceway It is possible that 2 to 10 undulations will appear compliantly, and vibrations that are 2 to 10 times higher than the rotational speed will appear during operation.

If there are splines or tight-fit keys near the journal where the bearing is mounted, it can also cause waviness in the bearing raceways. The unevenness of the mounting surface in the axial direction or the chamfering radius of the shoulder is too large, which will also cause similar deformation of the ferrule, resulting in vibration and noise. Therefore, if the above conditions are found during inspection of the mounting surface, it must be repaired or replaced with matching parts of satisfactory quality.