Joint bearing is a kind of sliding bearing with a special structure.Its structure is simpler than that of rolling bearings. It is mainly composed of an inner ring with an outer spherical surface and an outer ring with an inner spherical surface. It can withstand larger loads. According to its different types and structures, it can withstand radial loads, axial loads or combined radial and axial loads that exist at the same time.Joint bearings are generally used for swing movement (i.e. angular movement) with lower speeds. Since the sliding surface is spherical, it can also be tilted within a certain angle range (i.e. self-aligning movement), and it can still work normally when the support shaft and the shaft shell hole are not at the same degree of eccentricity. When the degree of eccentricity is large, it can still work normally.

Characteristics of joint bearings

Joint bearings can withstand large loads.According to its different types and structures, it can withstand radial loads, axial loads, or combined radial and axial loads at the same time.Since the outer spherical surface of the inner ring is inlaid with composite materials, the bearing can produce self-lubricating during work.Generally used for low-speed swing movement and low-speed rotation, it can also be tilted within a certain angle range. When the support shaft and the shaft shell hole are not centered at a large degree, it can still work normally.Self-lubricating joint bearings are used in water conservancy, professional machinery and other industries.

Classification of joint bearings

(1) Joint bearings can be divided into centripetal joint bearings, angular contact joint bearings, thrust joint bearings and rod end joint bearings according to the direction and nominal contact angle of the load they can withstand and the structure.

(2) The nominal contact angle of centripetal joint bearings (GE type) is 0 degrees, which is suitable for bearing radial loads and smaller axial loads.

(3) Angular contact joint bearings (GAC type) are divided into two types: angular contact centripetal joint bearings and angular contact thrust joint bearings.

  ①The nominal contact angle of angular contact centripetal joint bearings is greater than 0 degrees but less than or equal to 30 degrees, which is suitable for bearing combined loads with radial loads and axial loads acting at the same time.；

  ②The nominal contact angle of angular contact thrust joint bearings is greater than 30 degrees and less than 90 degrees, which is suitable for bearing axial loads and joint loads, but at this time its radial load shall not be greater than 0.5 times the axial load.

(4) The nominal contact angle of thrust joint bearings (GX) is 90 degrees, which is suitable for bearing axial loads but not radial loads.

(5) Rod end joint bearings are suitable for bearing axial loads with smaller radial loads (generally less than or equal to 0.2 times the radial load).

Performance of joint bearings

Since the structure and working mechanism of joint bearings are completely different from rolling bearings, joint bearings have their own technical characteristics and maintenance requirements.

Operating temperature

The allowable operating temperature of joint bearings is mainly determined by the matching materials between the sliding surfaces of the bearings, especially the sliding surfaces of plastic materials of self-lubricating joint bearings, which have a downward trend in carrying capacity at high temperatures.For example, when the sliding surface material of a lubricated joint bearing is paired with steel/steel, the allowable operating temperature depends on the allowable operating temperature of the lubricant.However, for all lubricating and self-lubricating joint bearings, they can be used in the temperature range of -30℃-+80℃ and maintain the correct bearing capacity.

Inclination

The inclination of joint bearings is much larger than that of general centering rolling bearings, and it is very suitable for use in support parts with low concentricity requirements. The inclination of joint bearings varies with the size, type, sealing device and support form of the bearing. Generally, the inclination range of centripetal joint bearings is 3°--15°, the inclination range of angular contact joint bearings is 2°-3°, and the inclination range of thrust joint bearings is 6°-9°.

Cooperate

Under no circumstances shall the fit selected by the joint bearing cause uneven deformation of the ferrule. The choice of the nature and grade of the fit must be determined according to the working conditions such as bearing type, support form and load size.

Loading and unloading

The loading and unloading of joint bearings should follow the following principles, that is, the force exerted by assembly and disassembly cannot be transmitted directly through the spherical sliding surface.In addition, auxiliary loading and unloading tools, such as sleeves, disassemblers, etc., should be used to apply the loading and unloading force exerted by the outside world directly and evenly to the matching ferrule, or auxiliary methods such as heating should be used for load-free loading and unloading.

Install

When assembling the joint bearing series, it is necessary to pay special attention to the position of the dividing surface of the outer ring.In order to avoid the load acting directly on the dividing surface, the dividing surface needs to be maintained at right angles to the conforming direction.

lubrication

When the load is applied and the speed generated by the swing movement is very small, the oil-fed joint bearing can be operated without lubrication.Nevertheless, under normal circumstances, it is necessary to replenish oil regularly.During the initial installation and operation, it is recommended that the lubrication cycle should be moderately shortened.Non-oil-fed joint bearings can be used without lubrication.However, if lithium soap-based grease is added before operation, the service life of joint bearings can be extended even more.If grease is injected into the space around the bearing, the joint bearing will be more effective in protecting against the invasion of dust and foreign objects.

Application of joint bearings

Joint bearings are widely used in engineering hydraulic cylinders, forging machine tools, construction machinery, automation equipment, automobile shock absorbers, water conservancy machinery and other industries.Introduction and classification of joint bearings Joint bearings are spherical plain bearings, and the basic type is composed of inner and outer rings with spherical sliding spherical contact surfaces.Depending on its structure and type, it can withstand radial loads, axial loads, or combined radial and axial loads acting at the same time.

Because the spherical sliding contact area of the joint bearing is large and the inclination angle is large, it is also because most joint bearings have adopted special process treatment methods, such as surface phosphating, galvanized, chrome-plated or outer sliding surface lining, inlay, spraying, etc.Therefore, it has a large load capacity and impact resistance, and has the characteristics of corrosion resistance, wear resistance, self-aligning, good lubrication or self-lubricating without lubricating dirt pollution, even if the installation is misplaced, it can work normally.Therefore, joint bearings are widely used in swing movement, tilt movement and rotary movement with lower speeds.