Machine tool bearing is an important part of machine tool equipment, and its accuracy and stability directly affect the performance and processing quality of machine tools. The inner and outer ring matching of bearing is the key link in the process of bearing installation and operation. Selecting the appropriate matching mode is of great significance to ensure the normal operation of bearing and improve the service life of bearing. This article will be a detailed introduction to the selection of the inner and outer ring of the machine tool bearing to help the reader better understand and choose the suitable bearing.
The selection of the inner ring fit needs to consider the operating conditions of the bearing, the tolerance of the journal and the stiffness of the shaft. In general, the inner ring is fitted with interference fit or gap fit.
Interference fit
Interference fit is suitable for the case that the bearing needs to bear a large radial force and axial force during operation, and the case that a high concentricity between the bearing and the shaft needs to be ensured. The selection of interference fit requires consideration of journal tolerances and shaft stiffness to ensure a firm fit and avoid bearing damage. In the selection of interference, it is necessary to consider the radial clearance of the bearing, the tolerance of the shaft and the temperature change.
Gap fit
The clearance fit is suitable for the case that the bearing does not need to bear a large radial force and axial force during operation, and the case that the bearing needs to be able to rotate freely. The choice of clearance fit needs to take into account the tolerance of the journal and the stiffness of the shaft to ensure that the bearing can rotate freely and avoid bearing damage. When selecting the clearance amount, it is necessary to consider the radial clearance of the bearing, the tolerance of the shaft and the temperature change.
The selection of the outer ring fit needs to consider the tolerance of the bearing seat, the operating conditions of the bearing and the stiffness of the shaft. Under normal circumstances, the outer ring is fitted with a clearance fit.
Gap fit
Clearance fit is suitable for situations where bearings need to be able to rotate freely during bearing operation, and where factors such as thermal expansion need to be considered. The choice of clearance fit needs to take into account the tolerance of the bearing seat and the stiffness of the shaft to ensure that the bearing can rotate freely and avoid bearing damage. When selecting the clearance amount, it is necessary to consider the radial clearance of the bearing, the tolerance of the bearing seat and the temperature change.
According to different usage scenarios and requirements, relevant collocation suggestions are given:
High-precision machine tools: For high-precision machine tools, in order to ensure the high accuracy and stability of the bearing, the inner ring and the outer ring should use interference fit.
Heavy-duty machine tools: For heavy-duty machine tools, in order to ensure the bearing capacity and life of the bearing, the inner ring should be used for interference fit, and the outer ring can be used for clearance fit.
High-speed machine tools: For high-speed machine tools, in order to ensure the high-speed running performance and stability of the bearing, the inner ring and the outer ring should use interference fit.
High temperature environment: For machine tool bearings working in high temperature environment, in order to ensure the normal operation and life of bearings, interference fit should be used in the inner and outer rings, and the influence of thermal expansion and other factors should be considered.
When selecting the inner and outer rings, it is necessary to consider the specific working conditions and requirements to avoid losses caused by improper selection. At the same time, the following points should also be noted:
The selection of fit tolerance should be reasonable, not only to ensure a firm fit, but also to avoid excessive interference or clearance caused by bearing damage.
For interference fit, the stiffness of the shaft and bearing seat, as well as the ease of installation and removal, need to be considered.
For clearance fit, factors such as radial clearance of the bearing, tolerance of the shaft and temperature change need to be considered to ensure that the bearing can rotate freely and avoid bearing damage.
When selecting the inner and outer ring fit, it is also necessary to consider factors such as the type, size and accuracy level of bearings.
This paper introduces the principles and methods of the selection of the inner and outer ring fit of machine tool bearings, including the selection of interference fit and clearance fit, matching suggestions and points for attention. It is of great significance to choose the appropriate inner and outer ring fit to ensure the normal operation of the bearing and improve the service life of the bearing. Therefore, in the selection and use of machine tool bearings need to be fully considered and analyzed with the inner and outer rings. The future research direction can further explore the characteristics and differences of the inner and outer ring matching of bearings of different types, different structures and different materials, and provide a more accurate basis for the design and application of machine tool bearings.
