Technical performance of joint bearings

Technical performance of joint bearings

First, the basic concept
 1 Radial dynamic load rating: Radial load when the dynamic stress of the working surface in the joint bearing reaches the maximum allowable stress.
2 Axial dynamic load rating: The axial load when the dynamic stress of the working surface in the joint bearing reaches the maximum allowable stress.
3 Lifetime: The total number of times the joint bearing works to swing when the friction coefficient of the joint bearing reaches the specified limit value or the joint bearing wear exceeds the specified limit value.
4 Radial equivalent dynamic load: A constant radial load under which the contact stress of the working surface in the joint bearing is equivalent to the actual load. It is used to calculate the service life of joint bearing when it is used for radial joint bearing, angular contact joint bearing and rod end joint bearing while bearing radial load and axial load. In general, it is recommended not to exceed 30% of the radial load for the axial load of the radial and angular contact joint bearings. The axial load of the rod end joint bearing is recommended not to exceed 20% of the radial load.
5 Axial equivalent dynamic load: A constant axial load under which the contact stress of the working surface in the joint bearing is equivalent to the actual load. For the calculation of joint bearings for thrust joint bearings bearing both radial and axial loads
Life expectancy. In general, the radial load on thrust joint bearings is recommended not to exceed 50% of the axial load.
6 Swing angle β: The angle between a certain diameter of the swinging ferrule and the two extreme positions. 7 Pendulum: When a point on the swinging ferrule of the joint bearing swings by 2β, it is a pendulum.

Joint bearing application
Joint bearings are widely used in engineering hydraulic cylinders, forging machine tools, engineering machinery, automation equipment, automotive shock absorbers, hydraulic machinery and other industries. Joint bearing introduction and classification of spherical plain bearings, the basic type is made of spherical sliding spherical contact surface The inner and outer rings are composed. Depending on its structure and type, it can withstand radial loads, axial loads, or combined loads acting in both radial and axial directions. Because the spherical sliding contact area of the joint bearing is large, the inclination angle is large, and because most of the joint bearings adopt special processing methods, such as surface phosphating, galvanizing, chrome plating or outer sliding surface lining, inserting, spraying and the like. Therefore, it has large load capacity and impact resistance, and has the characteristics of corrosion resistance, wear resistance, self-aligning, good lubrication or self-lubricating and non-lubricating dirt pollution, even if the installation is misaligned, it can work normally. Therefore, joint bearings are widely used for low-speed oscillating motions, tilting motions, and rotational motions. Joint bearing composition The joint bearing is mainly composed of an inner ring with an outer spherical surface and an outer ring with an inner spherical surface. Technical performance of the joint bearing Since the structural form and working mechanism of the joint bearing are completely different from those of the rolling bearing, the joint bearing has its own technical characteristics and maintenance requirements.

Joint bearing
(1) Operating temperature
The allowable operating temperature of the joint bearing is mainly determined by the mating material between the sliding surfaces of the bearing, especially the sliding surface of the plastic material of the self-lubricating joint bearing, and its bearing capacity will decrease 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 lubricated and self-lubricating joint bearings, they can be used in the temperature range of -30 ° C ~ +80 ° C, and maintain the correct bearing capacity.

(2) Inclination
The inclination of the joint bearing is much larger than that of the generally adjustable rolling bearing. It is suitable for use in the support part where the concentricity is not high. The inclination of the joint bearing varies with the size, type, sealing device and support form of the bearing. The inclination angle of the radial spherical plain bearing is 3° to 15°, the inclination angle of the angular contact joint bearing is 2° to 3°, and the inclination of the thrust joint bearing is 6° to 9°.

(3) Coordination
In any case, the joints selected for the joint bearing shall not cause uneven deformation of the ferrule. The selection of the mating nature and grade must be determined according to the working conditions such as bearing type, support form and load size.

(4) Loading and unloading
The loading and unloading of the joint bearing should follow the principle that the force applied by the assembly and disassembly cannot be transmitted directly through the spherical sliding surface. In addition, auxiliary loading and unloading tools, such as sleeves, detachers, etc., should be used to directly and uniformly apply the loading and unloading force applied by the outside to the ferrule to be fitted, or to perform load-free loading and unloading by an auxiliary method such as heating.