Rolling Bearings: Terminology and Definitions
Rolling bearings are important components in many applications. While they are often used in specialized machinery and equipment, they are also found in everyday items like small appliances. Bearing terminology associated with all types of bearings can be confusing for users, so it is important for them to understand the jargon and definitions associated with these components.
Axial Load: A force that is applied in a direction parallel to an axis or shaft. The magnitude of the axial force affects the loading capacity of a bearing.
Cage: The separation between rolling elements, like balls or rollers, within a bearing that helps to keep them evenly spaced. The cage also helps reduce friction and heat generated from operation.
Clearance: The space between the rolling elements and the inner and outer races of the bearing. The clearance can be adjusted to help reduce friction and wear.
Contact Angle: The angle between the line of action of the rolling elements and the bearing race divided by the line of the center of two bearing rings. The contact angle affects the load capacity and stability of the bearing.
Inner Raceway: The surface on the inside of the bearing that the bearing elements roll against.
Load Direction: Refers to the direction of a load that is being applied to the bearing. A radial load is applied perpendicular to the axis of the bearing while an axial load is applied parallel to the axis of the bearing.
Load Rating: Refers to the force that a bearing is designed and able to withstand without deformation.
Outer Raceway: The surface on the outside of the bearing that the rolling elements roll against.
Preload: A type of load applied to a bearing whose purpose is to minimize axial movement or the clearance between bearing elements.
Radial Load: A force that is applied at a right angle to an axis or shaft.
Spherical Contact Bearings: Radial ball bearings that use two rows of balls with a self-aligning feature. This feature helps them align themselves with the load vectors that are applied to the bearing.
Thrust/Axial Load: A force that is applied in a forward or backward direction, parallel to an axis or shaft.
Tolerances: The allowable variations from the specified dimensions of a bearing. Tolerances affect the bearings performance, load capacity, and accuracy of the motion of the bearing.
Typical Lifetime: The average operational period for a bearing based on the mean time between failures.
Radial or Deep Groove Bearings: Single or double row bearings that are designed to carry both rotational and radial loads. The races (inner and outer) are shaped like deep grooves which help them conform to various misalignments.
Back-to-Back Mounted Bearings: This type of assembly combines two bearings that are mounted opposite each other in a single housing. This reversible design makes them resistant to radial forces in both directions.
Four-Point Contact Bearings: Cylindrical roller bearings that are designed to carry both radial and axial load in four directions. They are self-aligning to help them keep up with the rigors of changing applications.
Angular Contact Bearings: Single or double row bearings used to carry radial and axial load in one direction. They are typically found in applications that need high precision, such as robotics, medical equipment, and aerospace.
Insert Bearings: Small bearings that are inserted into a housing to take up loads from a rotating shaft. They are often used in applications that require low-speed and low-torque operation.
Linear Ball Bushing Bearings: Self-aligning bearings that provide a low-friction support for linear motion. They are often used in automated machinery and electronic equipment.
Tapered Bearings: Sub-type of roller bearings designed to take up radial, thrust, and combined loads in one direction. The tapered rollers help to align themselves with the load vectors and enable them to handle larger load capacities.
Cylindrical Roller Bearings: Single or double row bearings used to carry radial loads. They are designed to align themselves with the load vectors and are used in various types of machinery.
Needle Roller Bearings: Single row bearings that are used to carry both radial and thrust loads in one direction. Their small diameter and light weight make them ideal for applications with limited space and limited load capacity.
Conclusion
Rolling bearings are an essential part of many applications. There are a variety of bearing types and it is important for users to understand the different terminology associated with these components. This article has provided insight into the definitions and jargon associated with rolling bearings, which should help users make an informed decision when selecting a bearing for their application.
