Deep groove ball bearings
Deep groove ball bearings are the most widely used type of bearings. They are simple in design and require little attention in operation. Primarily they are used to carry radial loads, but can also take considerable axial loads from both directions. After mounted on the shaft, they are capable of restricting the relative displacement of the shaft or housing within the axial clearance limit of the bearing.

Compared with other types of bearings in the same size, deep groove ball bearings are distinguished for high speed operations. They can be used to take both radial and thrust loads in high speed rotating machine parts, where thrust bearings will be unsuitable.

After deep groove ball bearings are mounted on the shaft, they are able to limit the two directions of axial displacement on shafts or housings in the extent of internal axial clearance. Therefore, they can be positioned axially. In addition, this type of bearings has certain aligning ability, while misaligning with housing by 2’-10’, they can also operate normally, but the operating life would be reduced. The deep grooves ball bearings are commonly fitted with pressed steel cages, for large-size bearings, machined metal cages are used. The deep groove ball bearings are widely used in automotives, tractors, machine tools, motors, water-pumps, agriculture mechanics, textile mechanics, etc.


Angular contact ball bearings
Angular contact ball bearings are particularly suitable to carry combined load, radial load as well as thrust load in one direction. Three kinds of contact angle: 15°, 25°, 40°are available. The greater the contact angle, the higher the axial load carrying capacity of the bearing will be; and bearings with smaller contact-angles are recommended for high speed applications. They can be arranged in duplex (pairs), namely, “face-to-face” or “back-to-back”, and “in tandem”. Bearings in duplex arrangement are extremely useful for high speed applications where the load to be carried is too great for a single bearing, or the axial loads to be carried are in both directions and the axial clearance is to be controlled. The duplex bearings can be preloaded as required to increase the stiffness of the spindle on which these bearings are mounted.


Tapered roller bearings
Tapered roller bearings are used to carry combined axial and radial loads, in which the radial load is predominant. These bearings are of separable design, i.e. the rollers retained by the cage constituting an assembly with the inner ring can be separated from the outer ring. The outer rings are made interchangeable. The axial clearance can be slightly adjusted during mounting and operation. Single row tapered roller bearings restrict the relative axial displacement of shaft or housing in one direction. Any misalignment between shaft and housing should be avoided during mounting. Since an induced axial load will appear by applying a radial load, when two tapered roller bearings being used on a spindle, they should be mounted “face-to-face” or “back-to-back”, so as to cancel the axial loads thereof induced. Double row tapered roller bearings are recommended for heavy loads.


Cylindrical roller bearings
Cylindrical roller bearings are commonly separable and easy to mount and dismount. They can be divided into single row, double row and multi-row cylindrical roller bearings. The widely used bearings are cylindrical roller bearings with cage. There are single or double row bearings with a full complement of roller and other bearing arrangements. Cylindrical roller bearings have high radial load carrying capacity and are also suitable for high speeds.

According to ribs, the single-row cylindrical roller bearings can be separated into type N, type NU, type NJ, type NF and type NUP, etc . Cylindrical roller bearings are not capable of limiting axial displacement of shaft (housing) .If the displacement is not permitted, they are usually used with other types of bearings (e.g. deep groove ball bearings).

Cylindrical roller bearings are mainly used in large electric motors, machine tool spindles, axle boxes of rail vehicles, and gear boxes of automotives and tractors.


Thrust bearings
Thrust bearings are separable type bearings. This type of bearings can be divided into single direction thrust ball bearings, double direction thrust ball bearings, cylindrical roller thrust bearings and tapered roller thrust bearings. Single direction thrust ball bearings can carry axial loads from one direction only, while double direction thrust bearings are able to carry loads in both directions, and they are not competent to confine the radial movement of the shaft or housing. The limiting speed for this type of bearing is rather low, so they are not applicable to high speed operations.

Cylindrical roller thrust bearings are separable. They are only able to carry axial load in one direction and slight shock loads, and limit axial displacement of shaft (or housing) in one direction, so they can be loaded axially. Their load carrying capacity is much higher than thrust ball bearings. When the roller roll, due to difference on velocity between the both ends of rollers, the slide will certainly produce on the raceway of rings. Therefore, the limiting speed of this type of bearings is lower than thrust ball bearings, usually are applied to low speed applications. Cylindrical roller thrust bearings mainly used in large machine tools, large gear-box in ship, etc.

Tapered thrust bearings can only carry axial loads in one direction, and limit the axial displacement in one direction, so they can be located axially. By comparison with cylindrical roller thrust bearings, they have higher load carrying capacity, relatively lower slide, but limiting speed is lower. They are widely used in construction mechanisms, automotives, generator equipments, etc.


Self-aligning bearings
Self-aligning bearings have the performance of self-aligning, so it can automatically adjust axis unrighteousness arising from deflection of the axis or the casing or the misalignment. It can be divided into self-aligning ball bearings and self-aligning roller bearings according to the difference of rollers.
Self-aligning ball bearings have two rows of balls and a common concave sphere raceway in the outer ring. The bearing is consequently self-aligning and insensitive to angular misalignments of the shaft relative to the housing. It is particularly suitable for applications where considerable shaft deflections or misalignment are to be expected. Additionally, the self-aligning ball bearing has the lowest friction of all rolling bearings, which enables it to run cooler even at high speeds. Double row self-aligning ball bearings are mainly used to carry radial loads and light axial loads, but can’t carry pure axial loads.
Self-aligning roller bearings can carry not only larger radial loads but also certain axial loads. Because the outer ring rollway nest of this type is spherical, the self-aligning roller bearings have the performance of self-aligning. It applies to carry heavy loads and impact loads, widely used in metallurgy, mill, mining, oil, paper, cement, pressing sugar industry, etc.


Slewing bearings
Slewing bearings are usually large-size bearings that can accommodate combined loads including axial loads, radial loads and lifting moments. These loads can be accommodated either singly or in combination in any direction. According to different structural types, slewing bearings can be divided into four-point contact ball slewing bearings, double-row angular contact ball slewing bearings, crossed tapered roller slewing bearings, crossed cylindrical roller slewing bearings and triple-row cylindrical roller slewing bearings. Every kind of slewing bearings above-mentioned is separated into bearings without gears, bearings with an internal gear and bearings with an external gear in the light of whether the bearing is with gears and the location of gears.
Generally, slewing bearings have mounting holes, lubricant holes and seals which can satisfy different needs of host machine worked in different conditions. On the other hand, slewing bearings possess certain features, for example, its structure is compact, the guidance is convenience, the mounting is simple and the maintenance is easy, etc.

Based on different structural features, slewing bearings are respectively able to meet needs of host machine worked in different loading condition. Among the rest, four-point contact ball slewing bearings possess a capacity of higher dynamic loads, while crossed cylindrical roller slewing bearings possess a capacity of higher steady loads. Crossed tapered roller slewing bearings have higher stiffness and running accuracy owing to preloads. Because triple-row cylindrical roller slewing bearings lead loading capacity to the short-transverse of bearings and every load is accommodated by different raceways and roller groups, the dimension of bearings can be greatly narrowed. Consequently, the host machine can be more compactable in the same stressed condition. Thus, triple-row cylindrical roller slewing bearings are a type of slewing bearings of higher load-supporting capacity.

Slewing bearings are widely used in large reversible mountings such as lifting machinery, mining machinery, building machinery, port machinery, and missile launchers and so on.