• Shandong JNLL Bearing Co., Ltd.
• 2023-10-23

Product Introduction

Deep groove ball bearings mainly bear radial loads and can also bear both radial and axial loads. When it only bears radial load, the contact angle is zero. When deep groove ball bearings have 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 limit speed is also very high.
However, due to the existence of gaps in deep groove ball bearings, relative movement of the inner and outer rings will occur under the action of loads, which will reduce the hardness of the bearings and cause axial and radial vibration of the bearings. This will affect the working accuracy and lifespan of the machine. To reduce this vibration, for high-precision and high-speed mechanical equipment, preloading is often used when installing deep groove ball bearings. This means that a certain radial or axial load is applied to the bearings during installation to eliminate their original clearance, and it can 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 preload control, namely bearing structure and preload 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 will change with the heating of the shaft system components. When the speed is high and the speed range is large, using an elastic preloading device can reduce the impact of temperature and speed on the preloading. 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、 Purpose of preloading
By preloading the spindle 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, there will be no clearance between the ball and raceway due to external loads, thereby improving the spindle's rotational accuracy, increasing the spindle's stiffness, and extending its service life, It can also reduce noise.
2、 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 working loads and high rotational speeds, it is advisable to adopt a smaller preload due to the tendency to generate heat and expansion.
The structural design of deep groove ball bearings should be reasonable while also possessing durability, in order to have a longer bearing service life. The rationality, stability, and performance of various processing techniques for deep groove ball bearings can also affect the lifespan 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 processes 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. When installing thin-walled bearings, they should be determined based on the bearing structure, size, and the mating 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.