Three Ways To Guide Bearing Cages

As an important component of the bearing, the cage plays the role of guiding and separating the rolling elements. The guiding role of the cage actually refers to the correction of the running of the rolling elements. This correction is achieved through the collision between the cage and the surrounding parts.

There are three general bearing cage guiding methods: rolling element guiding, inner ring guiding, and outer ring guiding.

Rolling element guiding:

The standard structure of the general design is rolling element guiding. For example, short cylindrical roller bearings use rolling element guiding. The cage does not contact the flange surface of the inner and outer rings. The cage can be universal, but when the speed of the rolling element increases at high speed, the rotation is unstable. Therefore, rolling element guiding is suitable for medium speed and medium load, such as gearbox bearings.

The cage of the rolling element guided bearing is located in the middle of the rolling element. There is no contact or collision between the cage and the inner and outer rings of the bearing. The collision between the cage and the roller corrects the roller movement and separates the rollers at a certain equidistant position.

Outer ring guiding:

The outer ring is generally stationary, and the outer ring guiding facilitates the entry of lubricating oil into the guide surface and raceway. High-speed gearboxes are oil mist lubricated, and using a rotating inner ring guide will squeeze out the oil. The outer ring guided bearing cage is located on the side of the rolling element close to the outer ring. When the bearing is running, the bearing cage may collide with the outer ring of the bearing to correct the cage position.

Outer ring guidance is generally used in high-speed and stable load conditions. Take cylindrical roller bearings as an example. It only bears a fixed value of axial load. The speed of each rolling element does not change much during rotation, and the rotation of the cage will not be unbalanced.

Inner ring guidance:

The inner ring is generally a rotating ring, and provides rolling elements with drag torque during rotation. If the bearing load is unstable or the load is light, slippage will occur.

If the cage is guided internally, an oil film is formed on the guide surface of the cage. Due to the friction of the oil film, the inner ring in the non-load area gives the cage a drag force, thereby increasing the additional driving torque of the cage on the rolling element, which can prevent slippage.

The inner ring guided bearing cage is located near the inner ring of the rolling element. When the bearing is running, the cage may collide with the inner ring of the bearing, thereby correcting the cage position.

The three cage guide methods may appear in different types of bearings, including performance reasons, and the design and manufacturing of the bearing itself. Engineers can choose according to their needs. But sometimes engineers have no choice. In any case, the different performance of different cage guide methods should be noted.

The differences between the three cages are mainly manifested in: The performance differences of the bearings with these three cage guide methods are mainly manifested in the speed performance differences under different lubrication conditions.

Bearings with three cage types can be used for oil lubrication and grease lubrication.