The fit of thrust bearing and shaft is generally transition fit, and the fit of seat ring and bearing seat hole is generally clearance fit. The middle shaft ring of bi-directional thrust bearing should be fixed on the shaft to prevent rotation relative to the shaft. The installation method of thrust bearing is generally the case of shaft rotation, so the fit of inner ring and shaft is over-win fit, and the fit of bearing outer ring and bearing chamber is clearance fit.
When installing thrust ball bearings, the verticality of shaft ring and shaft center line should be checked. The method is to fix the dial meter on the end face of the case, so that the contact head of the table rotates the bearing above the raceway of the bearing shaft ring, while observing the dial meter pointer, if the pointer swings, it indicates that the shaft ring and the shaft center line are not vertical. When the shell hole is deep, you can also use the extended micrometer head for inspection. When the thrust ball bearing is installed correctly, its seat ring can automatically adapt to the rolling of the rolling body to ensure that the rolling body is located in the raceway of the upper and lower ring. If it is installed backwards, not only does the bearing work abnormally, but also the mating surface will suffer serious wear and tear. Because the difference between the shaft ring and the seat ring is not very obvious, the assembly should be extra careful, do not make mistakes. In addition, there should be a gap of 0.2-0.5mm between the seat ring of thrust ball bearing and the bearing seat hole to compensate for errors caused by inaccurate processing and installation of parts. When the center of the bearing ring is offset in operation, this gap can ensure its automatic adjustment to avoid contact friction and make it run normally. Otherwise, severe bearing damage will be caused.
Planar thrust ball bearings are widely used in assembly because they mainly bear axial loads. Although the installation and operation of thrust ball bearings are relatively simple, errors often occur in actual maintenance, that is, the installation position of the tight ring and loose ring of the bearings is not correct, resulting in the loss of the bearing and the journal is quickly worn out. The inner ring of the tight ring is a transition fit with the shaft journal. 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 is greater than the resistance moment of the inner diameter fit, resulting in forced rotation of the tight ring and the shaft mating surface, which intensifies the wear of the shaft journal.
Therefore, the following points should be paid attention to when installing thrust ball bearings.
(1) distinguish the tight ring and loose ring of the bearing (according to the size of the inner diameter of the bearing, the aperture difference is 0.1 ~ 0.5mm).
(2) distinguish the static parts of the mechanism (that is, the parts that do not move, mainly refers to the assembly).
(3) No matter what the case, the loose ring of the bearing should always be on the end face of the stationary part.