Detailed explanation of thrust bearing
Thrust bearings are generally composed of two thrust washers or more thrust washers and several rolling elements. Generally, thrust washers are divided into shaft sheets and seat sheets. The most common types of rolling elements are iron or copper. The mass cage is combined into a whole. This type of bearing is most commonly defined as a steel ball thrust shaft
Thrust bearing is a special bearing used to bear axial force, that is, the bearing of the force in the direction parallel to the axis. Thrust bearing is also called thrust bearing
Thrust ball bearing is a separable bearing, the shaft washer and seat washer can be separated from the cage and steel ball components. The shaft ring is a ring that matches the shaft, and the seat ring is a ring that matches the bearing seat hole, and there is a gap between the shaft and the shaft; the thrust ball bearing can only bear the axial load,
One-way thrust ball bearings can only withstand axial loads in one direction.
Two-way thrust ball bearings can withstand axial loads in two directions;
Thrust ball bearings cannot limit the radial displacement of the shaft, and the limit speed is very low.
One-way thrust ball bearings can limit the axial displacement of the shaft and housing in one direction,
Bidirectional bearings can limit axial displacement in both directions.
Thrust roller bearings are used to bear the combined axial and radial loads with the main axial load, but the radial load shall not exceed 55% of the axial load. Compared with other thrust roller bearings, this kind of bearing has lower friction factor, higher speed and self-aligning performance.
The rollers of the 29000 bearing are asymmetric spherical rollers, which can reduce the relative sliding between the rollers and the raceway during operation, and the rollers are long, large in diameter, large in number of rollers, and high in load capacity. Oil lubrication is usually used. , Grease lubrication can be used in individual low-speed situations. In the design and selection, it should be preferred;
80000 type thrust cylindrical roller bearing, 90000 type thrust tapered roller bearing and AXK type thrust needle roller bearing can bear one-way axial load, which is much larger than thrust ball bearing in axial load capacity, and has high rigidity, Occupies a small amount of axial space.
Thrust cylindrical roller bearings and thrust needle roller bearings are suitable for occasions with low rotational speed, and the rotational speed of thrust tapered roller bearings is slightly higher than that of thrust cylindrical roller bearings.
Application classification
Thrust bearings are divided into thrust ball bearings and thrust roller bearings.
Thrust ball bearings are further divided into thrust ball bearings and thrust angular contact ball bearings. The raceway ring matched with the shaft is composed of a washer with a raceway, a ball and a cage assembly, which is called a shaft washer, and the raceway ring that cooperates with the shell is called a The seat ring. The two-way bearing matches the middle ring with the shaft. The one-way bearing can bear the one-way axial load, and the two-way bearing can bear the two-way axial load. The bearing with spherical mounting surface of the seat ring has self-aligning performance, which can reduce the installation The influence of errors. Such bearings are mainly used in automobile steering mechanisms and machine tool spindles.
Thrust roller bearings are divided into thrust cylindrical roller bearings, thrust spherical roller bearings, thrust tapered roller bearings, thrust needle roller bearings. Thrust cylindrical roller bearings are mainly used in oil drilling rigs, iron and steel machinery. Thrust self-aligning This type of bearing is mainly used in hydraulic generators, vertical motors, propeller shafts for ships, tower cranes, extruders, etc. Thrust tapered roller bearings are mainly used for this type of bearings: one-way: crane hook, oil rig rotation Ring. Bidirectional: Rolling mill roll neck. Planar thrust bearing mainly bears axial load in the assembly, and it is widely used.
Although the installation operation of the thrust bearing is relatively simple, there are still mistakes in the actual maintenance, that is, the installation position of the tight ring and the loose ring of the bearing is incorrect, resulting in the failure of the bearing and the rapid wear of the journal. The tightening ring is installed on the end face of the stationary part, i.e. wrong assembly. The inner ring of the tight ring and the journal are in transition fit. When the shaft rotates, the tight ring is driven, and friction occurs with the end face of the stationary part. When the axial force (Fx) is applied, the friction torque will be greater than the matching resistance torque of the inner diameter, resulting in tightness. The mating surface of the ring and the shaft is forced to rotate, which aggravates the wear of the journal. Precautions
The following points should be paid attention to when installing the thrust bearing.
(1) Distinguish between the tight ring and the loose ring of the bearing (judging by the inner diameter of the bearing, the difference in the diameter of the bearing is O.1 ~ O.5mm).
(2) Distinguish the static parts of the mechanism (that is, the parts that do not move, mainly referring to the assembly).
(3) In any case, the loose ring of the bearing should always rest on the end face of the stationary part.
