Bearing internal clearance
Bearing internal clearance is closely related to the performance and service life of bearings. If the internal clearance of the bearing is insufficient, the bearing will generate heat and accelerate wear, and even cause seizure due to insufficient rolling retention force and poor lubrication. If it is too large, it will cause the bearing to vibrate, making the rotation rougher and may cause the bearing to fall off. Therefore, it is necessary to ensure that the bearing works in a suitable state, and to ensure its performance and service life. This requires us to understand and understand the internal clearance of the bearing.
The internal clearance of the bearing is defined as the total measurement gap when the outer ring of the bearing is stationary with the inner ring, that is, the clearance when the bearing is not subjected to external load. It also includes contact angle, bearing tilt and installation position of bearing ring and other factors. Due to various factors, chamfers and radius of bearing ring, manufacturing and machining accuracy vary from batch to batch. Therefore, the amount of machining allowance and gap in the assembled bearings are uncertain and should be tested. Generally, the maximum clearance C nom defined in the bearing standard is used as the reference value.
Bearing internal clearance is mainly related to the lubrication condition of bearing, manufacturing method and installation actual conditions of bearing, mainly c3 and c4. C3 is suitable for those bearing installations which are heavy in axial load and impact load, such as car and one-way bearing, etc. C4 is suitable for those bearing installations which are light in axial load or no axial load, such as bearing set containing thrust ball bearings, etc. bearings of different classes can work smoothly as long as the clearance is in a suitable state. When the bearing is working, due to various factors, the total clearance of the bearing is C 4 + C Theoretically, the smaller the value, the better.
When the internal clearance of bearings is improper, it will affect the bearing performance. If the bearing is too tight or too loose, it will cause the bearing to vibrate, shorten the service life and may cause an accident. Therefore, it is necessary to detect the internal clearance of bearings during installation and commissioning. The detection methods are mainly visual inspection method, micrometer method and axial micrometer method.
In short, bearing internal clearance is an important element to ensure the performance and service life of bearing. It needs to be accurately measured and controlled to meet the requirements. It is uncertain to rely on experience, data statistics and accuracy of measurement. The key is to judge the installation situation and characteristics of the bearing, select the proper bearing internal clearance, configure the suitable bearing to match the external load, and test and control the bearing internal clearance in the detection process to make it work normally.
