The importance of preloading on rolling bearings is reflected in which aspects

Deep groove ball bearings mainly bear radial loads and can also withstand both radial and axial loads simultaneously. When it only bears radial loads, the contact angle is zero. When deep groove ball bearings have a large radial clearance, they have the performance of angular contact bearings and can withstand large axial loads. The friction coefficient of deep groove ball bearings is very small, and the maximum speed is also high.

However, due to the existence of gaps in deep groove ball bearings, relative movement between the inner and outer rings will occur under the action of load, which will reduce the hardness of the bearing, cause axial and radial vibration of the bearing, and affect the working accuracy and service life of the machine. To reduce this kind of vibration, for high-precision and high-speed mechanical equipment, the pre tightening method is often used when installing deep groove ball bearings, which means that a certain radial or axial load is given to the bearings during installation to eliminate their original clearance. This can also cause elastic deformation between the bearing body and the inner and outer rings, effectively avoiding relative movement between the inner rings.

Generally, two methods are used to achieve pre load control: bearing structure and pre load compensation principle. When the speed is not too high and the speed range is relatively small, a steel preload is used to apply the preload, and the preload load will change with the heating of the shaft components. When the speed is high and the speed range is large, using an elastic preload device can reduce the influence of temperature and speed on the preload. This method is very effective in controlling the preload and is easy to operate, but once the bearing is assembled, its preload cannot be adjusted.

1、 The purpose of preloading

By preloading the main shaft bearing, the original clearance between the ball and raceway can be eliminated and elastic deformation can be formed. When the deep groove ball bearing is subjected to external loads, the bearing will have a certain degree of rigidity. When installing a bearing with the opposite direction of external load, the clearance between the ball and raceway will not be caused by external loads, thereby improving the rotational accuracy of the main shaft, increasing the stiffness of the main shaft, extending its service life, and reducing noise.

2、 The principle of preloading

The size of the preload is generally determined based on the spindle rotation accuracy, working load size, and rotational speed.

1. If the spindle load is small, the rotation accuracy is high, and the speed is low, a larger preload can be adopted.

2. For those with large workloads and high rotational speeds, it is advisable to adopt a smaller preload due to the tendency to generate thermal expansion.

The structural design of deep groove ball bearings should be reasonable while also having durability, in order to have a longer bearing service life. The rationality, stability, and performance of various processing techniques for deep groove ball bearings will also affect the service life of the bearings. The heat treatment and grinding processes that affect the quality of deep groove ball bearings are often directly related to the failure of the bearings. Research on the deterioration layer on the working surface of deep groove ball bearings indicates that the manufacturing of bearings generally requires multiple processing steps such as forging, heat treatment, grinding, turning, and assembly. The relationship between grinding process and bearing surface quality is very close.

The correct installation of deep groove ball bearings affects their lifespan, accuracy, and performance. Therefore, the design and assembly department should fully study the installation of deep groove ball bearings. Installation must be carried out according to the operating standards. The installation of thin-walled bearings should be determined based on the bearing structure, size, and fitting properties of the bearing components. The pressure should be directly applied to the end face of the tight fitting ring and should not be transmitted through the rolling element.