Industry Knowledge

Classification of thrust bearings:

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, and the raceway ring matched with the shaft is called a shaft washer, and the raceway ring matched with the housing is called a seat ring. The two-way bearing matches the middle ring with the shaft, the one-way bearing can bear one-way axial load, and the two-way bearing can bear two-way axial load. Bearings with a spherical mounting surface of the seat ring have self-aligning performance, which can reduce the influence of mounting 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 making machinery. Thrust spherical roller bearings are 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 bearing: one-way is suitable for crane hooks, oil rig swivels; two-way is suitable for rolling mill roll necks; plane thrust bearings mainly bear axial loads in assemblies, and are 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.

The difference between one-way thrust ball bearings and two-way thrust ball bearings:

One-way Thrust Ball Bearings - One-way thrust ball bearings consist of a shaft washer, a bearing seat washer, and a ball and cage thrust assembly. The bearings are separable, so installation is simple because the washers and balls and cage assemblies can be installed separately. There are two types of small one-way thrust ball bearings, which are with flat seat ring or with self-aligning seat ring. Bearings with self-aligning seat washers can be used with self-aligning seat washers to compensate for angular misalignment between the support surface in the housing and the shaft.

Two-way Thrust Ball Bearing--The composition of the two-way thrust ball bearing consists of three parts: a seat two-way thrust ball bearing, including a shaft washer, two seat washers and two steel ball-cage assemblies. The bearing is a separate type, and each part can be installed independently. The shaft washer matched with the shaft can bear the axial load in two directions, and can fix the shaft in both directions. Bearings of this type must not be able to withstand any delivery radial loads. The thrust ball bearing also has a structure with a seat pad. Since the mounting surface of the seat pad is spherical, the bearing has self-aligning performance, which can reduce the influence of installation errors.

Two-way bearings and one-way bearings use the same shaft washer, seat washer and steel ball-cage assembly.

Thrust bearing is a dynamic pressure bearing. To make the bearing work normally, the following conditions should be met: 

1. Lubricating oil has one-viscosity;

2. There is a certain relative speed between the moving and static bodies;

3. The two surfaces of relative motion are inclined to form an oil wedge;

4. The external load is within the specified range;

5. Sufficient amount of oil.