Rolling bearings are extremely important and common components in mechanical engineering. Their core function is to support rotating shafts, reduce frictional resistance, and ensure rotational accuracy.
I. What is a Rolling Bearing?
A rolling bearing is a precision mechanical component that uses rolling elements (such as balls or rollers) rolling between an inner and outer ring to achieve motion conversion. It transforms sliding friction into rolling friction, thereby significantly reducing frictional resistance, energy loss, and wear during motion.
II. Basic Structure of a Rolling Bearing
A typical rolling bearing usually consists of the following four parts:
Inner Ring: Mounted on the shaft and rotates with it.
Outer Ring: Mounted on the bearing housing or machine casing and usually stationary.
Rolling Elements: The core rolling elements that roll between the raceways of the inner and outer rings. Common types include ball bearings, cylindrical roller bearings, tapered roller bearings, and needle roller bearings.
Cage: Used to evenly separate the rolling elements, guide their proper movement, and prevent them from colliding and rubbing against each other.
Some bearings may also include additional components such as seals and dust covers to maintain lubrication and prevent contaminants from entering.
III. Main Types and Applications of Rolling Bearings
Based on the direction of the load and the shape of the rolling elements, rolling bearings are mainly divided into two categories:
1. Classification by Load Direction
Radial bearings: Primarily used to bear radial loads (forces perpendicular to the shaft). For example: deep groove ball bearings.
Thrust bearings: Primarily used to bear axial loads (forces parallel to the shaft). For example: thrust ball bearings.
Angular contact bearings: Can bear combined radial and axial loads simultaneously. The bearing's contact angle determines its axial load capacity. For example: angular contact ball bearings, tapered roller bearings.
2. Classification by Rolling Element Shape
Ball bearings: The rolling elements are spheres.
Deep groove ball bearings: The most commonly used type. Primarily bears radial loads, but can also bear certain bidirectional axial loads. Low friction, high speed, and low price. Widely used in motors, home appliances, automobiles, etc.
Angular contact ball bearings: Can withstand both radial and unidirectional axial loads simultaneously. Commonly used in pumps, gearboxes, machine tool spindles, etc.
Thrust ball bearings: Specifically designed to withstand pure axial loads. Cannot withstand radial loads. Commonly used in crane hooks, vertical water pumps, etc.
Roller bearings: Rolling elements are cylindrical, tapered, or drum-shaped rollers. Load capacity is generally higher than ball bearings of the same size, but the limiting speed is lower.
Cylindrical roller bearings: Rolling elements are cylindrical rollers, with very high radial load capacity. Mainly used in large and medium-sized motors, machine tool spindles, engines, etc.
Tapered roller bearings: Rolling elements are tapered rollers, capable of simultaneously with large radial and unidirectional axial loads. Used in pairs to withstand bidirectional axial loads. Widely used in automobile wheels, rolling mills, mining machinery, etc.
Self-aligning roller bearings: Have a self-aligning function, automatically compensating for coaxiality errors caused by installation errors or shaft bending. Used in applications requiring heavy loads and impact loads, such as papermaking machinery and mining crushers.
Needle roller bearings: Utilizing slender rollers, they have a compact radial structure and high radial load capacity. Suitable for applications with limited radial installation space, such as automotive gearboxes and connecting rods.
Rolling bearings are the "joints" of modern industry; their performance directly affects the precision, efficiency, lifespan, and reliability of the entire mechanical equipment. Selecting the appropriate bearing type, proper installation, and maintenance are crucial to ensuring the normal operation of mechanical equipment.
2025-11-07
