Double row cylindrical roller bearings belong to linear contact bearings, and their bearing capacity and stiffness are higher than those of point contact angular contact bearings. They are often used in the spindle systems of medium, large and heavy machine tools whose load is larger, the stiffness is higher but the speed is relatively low. ZZ Bearing (shanghai) co.,ltd., a ball bearing manufacturers in China, will share the assembly and adjustment method of double-row cylindrical roller bearings used in spindle systems with you.
If there are manufacturing errors in the spindles and bearings of China cylindrical roller bearings, the rotation accuracy of the spindle unit must be affected.
(1) The selective assembly of fore bearings: Because the radial run-out of the spindle at the front support has the greatest influence on the rotation accuracy of its end, the bearing selective assembly method should be adopted first to reduce the radial run-out at the front support.
(2) The selective assembly of rear bearings: The rotation accuracy of the spindle unit can be further improved by selecting the rear bearing after the selective assembly of the fore bearing.
The clearance amount in the spindle rolling bearing of China cylindrical roller bearings has an important influence on the working performance and bearing life of spindle unit. When the bearing works under a large clearance, the machining accuracy will be affected due to the deviation of the spindle position (radial or axial). In addition, the stiffness and vibration resistance of China cylindrical roller bearing spindle unit are greatly weakened. When the bearing clearance is adjusted to zero, the bearing zone increases, the force condition of the rolling body tends to be uniform, and the rotation accuracy of the spindle is improved. Therefore, keeping a reasonable clearance of the rolling bearing is an important measure to improve the rotation accuracy, stiffness and vibration resistance of spindle components.
There are many reasons that may cause the inner and outer ring mounting position of the spindle bearing to deviate, and cause the bearing rolling body and the inner and outer rings of the bearing to contact badly, resulting in the reduction of the spindle stiffness and rotation accuracy. The method to check the right installation of the inner and outer ring of the spindle bearing is as follows:
In the process of pre-tightening the inner ring of the bearing, it needs to constantly rotate the spindle, and observe the rotation condition of the bearing rolling body at the same time.
If the spindle can be rotated easily, and the rolling body of the bearing rotates with the spindle, it turns out that the inner and outer rings of the bearing are installed right. Sometimes, the spindle has been preloaded to a certain extent, there is a block when it is rotating, the individual rolling body does not rotate with the spindle, or the individual rolling body is loose when it is moved by hand ... If the above mentioned condition exists, it can be judged that the installation of the inner or outer bearing rings is not right.