Types of Ball Bearings
Ball bearings can be categorized into various types based on their structural types and performance characteristics, such as miniature ball bearings, deep groove ball bearings, angular contact ball bearings, self-aligning ball bearings, thrust ball bearings, and ball bearings with a cage between the rolling elements and the housing.
Miniature Ball Bearings: Miniature ball bearings are small-sized ball bearings ranging from 1 mm to 10 mm. They are available in both inch and metric sizes and are made from stainless steel or chrome steel. Depending on your application, AUBEARING also offers flanged, open, sealed, or shielded versions. Sometimes referred to as instrument bearings or miniature bearings, they are used in dental equipment, gyroscopes, anemometers, flow meters, miniature gearboxes, small motors, and radio-controlled models.
Deep Groove Ball Bearings: Deep groove ball bearings are the most common type of ball bearing. They have grooves on both the inner and outer sides of the bearing rings and can withstand both radial and axial loads. Known for their simple structure, long service life, high-speed capability, and ease of maintenance, they are widely used in various machinery such as power tools, automobiles, motorcycles, and agricultural machinery.
Thin-Section Ball Bearings: Thin-section bearings have a smaller cross-section relative to their diameter and can be categorized into angular contact type A, radial contact type C, and four-point contact type X thin-section ball bearings. Designed to save space, reduce design weight, and minimize friction, these bearings are widely used in national defense, aerospace, medical imaging, robotics, semiconductors, data storage, and machine tools. AUBEARING manufactures thin-section and ultra-thin-section bearings in inch or metric sizes, with options for chrome steel, stainless steel, and ceramic materials. These bearings typically carry radial loads and are available in open, shielded, or sealed versions. AUBEARING manufactures RealiSlim, Endura-kote Plated, RealiSlim Stainless Steel, Turntable Bearings, and UltraSlim thin-section bearings, which are equivalent to the well-known American brand KAYDON. Additionally, AUBEARING offers the 6700, 6800, and 6900 series thin-section bearings.
Angular Contact Ball Bearings: Angular contact ball bearings are designed to create a contact angle between the raceway and the ball. The main design feature of these bearings is that one shoulder of the ring is higher than the other. To function properly, angular contact bearings require a thrust load to be applied during operation. This load (or preload) creates a contact angle between the inner ring, the ball, and the outer ring. The contact angle can be 15°, 25°, or 40°. Angular contact bearings can withstand large thrust loads and moderate radial loads. They come in three types: single-row, double-row, and four-point contact angular contact bearings, and they must be used in pairs or combinations.
Flanged Ball Bearings: Flanged ball bearings have a flange on one end of the bearing. This design enhances the structural strength of the bearing and provides convenient mounting and positioning functions, bearing radial loads and light axial loads. Flanged ball bearings are designed for specific applications and come in various designs and cage options, as well as load and performance characteristics. However, all flanged bearings are designed to be very robust and resistant to water or contaminants, making them suitable for supporting heavy loads in machinery with rotary or linear motion.
Thrust Ball Bearings: Thrust ball bearings can withstand thrust loads during high-speed operation. They are divided into single-direction thrust ball bearings and double-direction thrust ball bearings based on load direction. Single-direction thrust ball bearings can bear unidirectional axial loads, while double-direction thrust ball bearings can bear bidirectional axial loads. Thrust ball bearings with a spherical housing washer can accommodate installation errors, reducing the impact of installation misalignment. Depending on the shape of the seat cushion, thrust ball bearings can be categorized into flat seat and aligning spherical seat types.
Self-Aligning Ball Bearings: Self-aligning ball bearings are designed to accommodate slight angular misalignments due to deflection or improper installation. They have two rows of balls, an inner ring with two raceways, and an outer ring with a spherical raceway that allows for self-alignment. These bearings can automatically compensate for concentricity errors caused by shaft bending or housing deformation, making them suitable for applications where strict concentricity is not guaranteed. They primarily bear radial loads and are not typically used for pure axial loads.
Stainless Steel Ball Bearings: Compared to standard bearings, stainless steel bearings have significant advantages in terms of material properties and precision control. They operate smoothly, produce low noise, and resist corrosion. The bearing rings and rolling elements are made from AISI 440C, 316, or 304 stainless steel, vacuum-hardened and tempered. The cage and seal ring skeleton materials are made from AISI 304 stainless steel. With the right lubricant, stainless steel bearings can be used in environments ranging from -60℃ to +300℃. They are commonly used in medical devices, cryogenic engineering, optical instruments, high-speed machine tools, high-speed motors, printing machinery, and food processing machinery.
Ceramic Ball Bearings: Ceramic ball bearings typically have very high hardness (70-90 HRc) and Young's modulus. This means they resist deformation under load while improving wear characteristics. Ceramic bearings can operate without lubrication and remain stable at high temperatures, resulting in minimal thermal expansion. Their high corrosion resistance makes them suitable for wet and chemically corrosive environments. Many engineering ceramics also have low density, which improves bearing speed by reducing centrifugal force and friction. Most ceramics lack free electrons, making them non-magnetic and excellent insulators. AUBEARING manufactures ceramic ball bearings from materials such as silicon nitride, zirconia, silicon carbide, and alumina.
Ball Bearing Seals and Shields
To maintain good lubrication conditions and a normal working environment for bearings, thereby extending their service life, ball bearings must have appropriate seals and shields to prevent lubricant leakage and the intrusion of dust, moisture, or other contaminants.
AUBEARING offers each type of ball bearing in open, sealed, and shielded options. Open ball bearings are the most common type. Shielded ball bearings have metal shields (Z or ZZ) on one or both sides to prevent dust and debris from contacting and affecting the bearing's operation. Most AUBEARING ball bearings are open or come with rubber or PTFE contact seals (RS or 2RS) or low-friction non-contact rubber seals (RZ or 2RZ). Open bearings usually come with oil lubrication. Shielded bearings, typically greased, are suitable for low-speed, low-friction applications.
Selecting the Right Ball Bearing
When selecting the type of ball bearing, consider the characteristics of each type and the specific working conditions, including grade, size, load, clearance, lubrication, seals, shields, open type, speed, alignment, rigidity, noise, and vibration, axial displacement, and cost. If the bearing is subjected to shocks while stationary, consider its static load rating. The inner and outer diameters of the bearing must match the shaft and housing dimensions, with options available in metric and inch sizes.
