Three ways to guide the bearing cage

As an important component of bearings, the cage plays a role in guiding and separating the rolling elements. The guiding function of the cage actually refers to the correction of the operation of the rolling elements. This correction is achieved through the collision between the cage and surrounding components.

There are three types of guide methods for general bearing cages: rolling element guide, inner ring guide, and outer ring guide.

Rolling element guidance:

The standard structure for general design is rolling element guidance, such as short cylindrical roller bearings, which use rolling element guidance. The retaining frame does not contact the edge surfaces of the inner and outer rings, and the retaining frame can be used interchangeably. However, when the rolling element speed increases at high speeds, the rotation is unstable. Therefore, rolling element guidance is suitable for medium and medium loads, such as gearbox bearings.

The bearing cage guided by rolling elements is located in the middle of the rolling elements. The cage and the inner and outer rings of the bearing do not come into contact or collide, and the collision between the cage and the rollers corrects the roller movement while separating the rollers at certain equidistant positions

Outer ring guidance:

The outer ring is generally stationary, and the outer ring guide facilitates the entry of lubricating oil into the guide surface and raceway. The high-speed gearbox is lubricated with oil mist, and the rotating inner ring guide will squeeze out the oil. The bearing cage guided by the outer ring is located on the side of the rolling element close to the outer ring. During the operation of the bearing, the bearing cage may collide with the outer ring of the bearing to correct the position of the cage.

Outer ring guidance is generally used for high-speed and stable load situations. Taking cylindrical roller bearings as an example, they only bear a fixed axial load, and the speed of each rolling element does not change much during rotation, and the rotation of the cage is not unbalanced.

Inner circle guidance:

The inner ring is usually a rotating ring that provides rolling elements to drag torque during rotation. If the bearing load is unstable or light, slippage may occur.

When the cage adopts internal guidance, an oil film is formed on the guide surface of the cage. Due to the friction of the oil film, the inner ring of the non load zone exerts drag force on the cage, thereby increasing the additional driving torque of the cage on the rolling elements and preventing slippage.

The bearing cage guided by the inner ring is located near the inner ring of the rolling element. During the operation of the bearing, the cage may collide with the inner ring of the bearing, thus correcting the position of the cage.

Three types of cage guidance methods may occur in different types of bearings, due to performance reasons as well as the design and manufacturing of the bearings themselves. Engineers can choose according to their needs. But sometimes engineers have no choice. Regardless, the different performance of different cage guidance methods should be taken into account.

The differences between the three types of retaining frames are mainly manifested in the performance differences of the bearings guided by these three retaining frames, which are mainly manifested in the speed performance differences under different lubrication conditions.

All three types of cage bearings can be used for oil lubrication and grease lubrication.