The importance of preloading deep groove ball bearings

Deep groove ball bearing mainly bear radial load, can also bear radial load and axial load at the same time. When it only bear radial load, the contact angle is zero. When the deep groove ball bearing has a large radial clearance, with angular contact bearing performance, can withstand large axial load, deep groove ball bearing friction coefficient is very small, the limit speed is also very high.

But because of the deep groove ball bearing clearance, in the inner and outer ring will be under the load of the role of relative movement, which will reduce the hardness of the bearing, so that the bearing axial and radial vibration, the machine's working accuracy and life will be affected. In order to reduce this vibration, for high precision and high speed mechanical equipment, often in the installation of deep groove ball bearings will use the pre-tightening method, that is to say, in the installation of a certain bearing radial or axial load, to eliminate its original clearance, and can make the bearing body and inner and outer ring to produce elastic deformation, so as to effectively avoid the relative movement between the inner ring.

Generally use the bearing structure and the use of preload compensation principle two methods to achieve the preload control. When the speed is not too high and the variable speed range is relatively small, the steel preload is used to apply the preload, which varies with the heating of the shaft parts. When the speed is high and the variable speed range is relatively large, a flexible preload device is used to reduce the effect of temperature and speed on the preload. In this method, the control preload is very effective and easy to operate, but once the bearing is assembled, its preload cannot be adjusted.

A, the purpose of preload

In the spindle bearing preload, can make the ball and raceway to eliminate the original clearance and the formation of elastic deformation, when the deep groove ball bearing bear external load, the bearing will have a certain rigidity, for the installation and external load bearing in the opposite direction, will not be subject to external load and make the ball and raceway gap, so as to improve the rotary accuracy of the spindle, increase the rigidity of the spindle and extend the service life, also can Reduce noise.

Second, the principle of preload

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

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

2, the work load is large, high speed, due to easy to produce heat expansion, it is appropriate to take a smaller preload.

Deep groove ball bearing structure design reasonable at the same time should also have sex, in order to have a long bearing life. Deep groove ball bearing each processing process of reasonableness, stability, sex will also affect the life of the bearing. Which affects the quality of deep groove ball bearing heat treatment and grinding process, often has a direct relationship with the failure of the bearing. For deep groove ball bearing work surface degradation layer of the study shows that the manufacturing of bearings generally need to go through forging, heat treatment, grinding, turning and assembly and other multi-processing procedures. Grinding process and bearing surface quality of the relationship is very close.