The use of rolling bearings is very extensive, such as basic functions, large mechanical equipment, aviation engines, etc. The clearance of the retainer directly affects the lubrication, oil film, heat generation, noise, and stability of the retainer of the rolling bearing, playing a key role in its performance. If the clearance of the retainer is not well controlled, it will not only cause instability of the bearing retainer and rolling element, but also play a crucial role in the performance of the rolling bearing, The collision force and friction force of the guide bearing ring increase rapidly, ultimately leading to damage to the cage and even affecting the service life of the bearing.

What are the specific effects of cage clearance on the wear of rolling bearings?

The factors that affect the normal use of rolling bearings are mainly reflected in the design of the cage pocket clearance and the cage guide clearance. If given the guide clearance conditions of the cage, increasing the pocket clearance will deteriorate the stability of the cage, and at the same time, inner ring guidance is more likely to make the cage unstable than outer ring guidance.

Through the study of the effect of different cage clearances on the wear of rolling bearings through cage clearances, the wear traces of cages, steel balls, etc. were found. The wear of cages and steel balls under different guide clearances and pocket clearances was compared, and the following conclusions were drawn:

(1) The guide clearance and the pocket clearance both affect the wear of the cage and steel ball, but the influence of the guide clearance on the wear of the cage is more significant than that of the pocket clearance.

(2) When the guide clearance is small, the wear on the guide surface of the cage is severe. As the guide clearance increases, the wear on the guide surface of the cage gradually decreases. At the same time, the guiding gap affects the wear of the cage pocket hole. When the guiding gap design is unreasonable, it exacerbates the wear of the cage pocket hole.

(3) The degree of wear on the guide surface and pocket of the cage gradually decreases as the pocket gap increases.

What are the factors that affect the stability of the bearing cage?

(1) Axial load

The axial load of a bearing refers to the load formed in the axial direction of the bearing, which is the force that pushes the inner ring of the bearing out of the outer ring.

When the bearing is running, the inner ring rotates while the outer ring remains stationary, with axial load as the independent variable. When the bearing speed is maintained at a certain level, the stability of the cage gradually improves with the increase of axial load. This is because the increase in axial force limits the sliding of the steel ball, reduces the collision frequency between the steel ball and the cage, and because the friction force is small under the action of lubricating oil, the vortex acceleration changes little, making the cage relatively stable.

(2) Radial load

Radial load refers to the load acting perpendicular to the axis of the bearing.

Keeping other conditions constant, with radial load as the independent variable, when the inner ring speed and axial load of the bearing are constant, the stability of the bearing cage gradually decreases with the increase of radial load. This is because increasing the interaction frequency between the radial load retainer and the outer ring will decrease, weakening the motion effect of the outer ring on the retainer and reducing its stability.

(3) Bearing speed

When the axial load and radial load of the bearing cage are constant, the stability of the cage gradually increases with the increase of bearing speed. This is because an increase in rotational speed will quickly push the retainer towards the outer ring guide surface during movement, resulting in an increase in the contact frequency between the retainer and the outer ring guide surface; At higher speeds, the geometric coupling between the ball and the cage is good, so the movement of the cage tends to be relatively stable.

(4) Gap ratio

Keeping other conditions constant, with the bearing clearance ratio as the independent variable, when the bearing load and inner ring speed are constant, the stability of the cage gradually decreases as the clearance ratio increases. This is because the increase in clearance ratio increases the collision between the ball and the bearing cage, and this force is asymmetric, resulting in a decrease in the stability of the bearing cage.

(5) External groove curvature coefficient

The curvature coefficient of the outer groove of the bearing is one of the important geometric parameters of the bearing, which has multiple impacts on the bearing.

Keeping other conditions constant, the external groove curvature coefficient is the independent variable. As the external groove curvature coefficient increases, the stability of the cage first gradually increases and then gradually decreases. This is because, under high-speed rotation of the bearing, an increase in the curvature coefficient of the outer groove will affect the formation of oil films between the components, resulting in a significant difference in the instability of the cage.

(6) Internal groove curvature coefficient

The curvature coefficient of the bearing groove is also one of the important geometric parameters of the bearing.

Keeping other conditions constant, the curvature coefficient of the inner groove is the independent variable. As the curvature coefficient of the inner groove increases, the stability of the cage first increases and then decreases. The reason is the same as the influence of the curvature coefficient of the external groove.