Bearing clearance is also called bearing clearance. The so-called bearing clearance refers to the amount of movement when the bearing is not installed on the shaft or the bearing box, the inner ring or the outer ring is fixed, and then the bearing clearance is not fixed to move radially or axially . According to the direction of movement, PTFE soft belt bearings can be divided into radial clearance and axial clearance. The size of the clearance (called the operating clearance) during the operation of the self-lubricating thrust gasket has an impact on the bearing's rolling fatigue life, temperature rise, noise, vibration and other properties.
The bearing clearance standard is not regulated by the country and depends on the usage: it is still a rather messy problem, briefly described as follows:
A. Selection criteria for clearance:
1. When using tighter cooperation, large temperature difference between the inner and outer rings, oil-free self-lubricating composite bearings are required to reduce the conflicting torque, deep groove ball bearings accept larger axial loads or need to improve the alignment performance, large clearance group should be selected.
2. When the rotation accuracy is high or the axial displacement needs to be severely restricted, a small clearance group should be selected.
B. Elements related to clearance:
1. Cooperation between bearing inner ring and shaft.
2. Cooperation between the outer ring of the bearing and the housing hole.
3. The influence of temperature.
Note: The reduction in radial clearance is related to the actual interference of the cooperative parts, the size of the general shaft diameter, and the wall thickness of the housing hole.
Use your fingers to check the axial clearance of the tumbling bearing. This method is used where the shaft end is exposed. When the shaft end is closed or you can’t view it with your fingers for other reasons, you can check whether the shaft scrolls flexibly.
2. Measurement method
(1) Check with a feeler gauge. The operation method is the same as that of checking the radial clearance with a plug, but the axial clearance should be
Where c-axial clearance, mm;
λ——Thickness of feeler gauge, mm;
β——bearing cone angle, (°).
(2) Check with a dial indicator, and use a crowbar to move the shaft so that the shaft is at the two poles. The difference between the dial indicator readings is the axial clearance of the bearing. However, the force applied to the crowbar cannot be too large, otherwise the shell will undergo elastic deformation, even if the deformation is small, it will affect the accuracy of the measured axial clearance.