Radial Preload Method and axial preload method for rolling ina bearings

Radial preloading method of rolling ina bearings

The radial jacking method is mostly used in the cone hole ina bearing radial load. The typical example is the double row precision short cylindrical roller ina bearing. The axial position of the INA Bearing relative to the tapered journal is adjusted by the nut, so that the inner ring has a proper expansion amount to obtain a radial negative clearance. This method is mostly used in the machine tool spindle and jet engine.

Axial preloading method of rolling ina bearings

The axial preloading method can be generally divided into two types: positioning preloading and constant pressure preloading.
In the positioning preloading, the appropriate preload can be obtained by adjusting the size of the bushing or gasket; The appropriate preload can also be adjusted by measuring or controlling the starting friction moment; The purpose of preloading can also be achieved by directly using the pair of double ina bearings with preload adjusted in advance. At this time, it is generally unnecessary for the user to adjust. In short, the relative position of ina bearings that have undergone axial preload will not change during use. Constant pressure preloading is a method to make INA Bearing get proper preloading by using coil spring, disc spring, etc. Generally, the rigidity of the preload spring is much smaller than that of INA Bearing. Therefore, the relative position of INA Bearing preloaded under constant pressure may change during use, but the preload amount is almost unchanged.

The comparison between positioning preloading and constant pressure preloading is as follows:

When the amount of preload is equal, the effect of positioning preload on the rigidity of ina bearing is greater, and the influence of rigidity change on the load of ina bearing is much smaller.
During the use of positioning preload, the axial length difference caused by the temperature difference between the shaft and ina bearing seat, the radial expansion caused by the temperature difference between the inner and outer rings, and the displacement caused by the load will change the preload; While constant pressure preloading is in use, the change of preloading can be ignored.

How to control the noise of rolling ina bearings

Raceway noise of rolling ina bearings and its control method

The raceway sound is a kind of smooth and continuous sound generated by the rolling body rolling on the raceway surface when the shaft is running. It is a unique basic sound that occurs in all rolling ina inlet bearings. The general bearing sound is the raceway sound plus other sounds.
The raceway sound of the ball bearing is irregular, and the frequency is above 1000Hz. Its main frequency does not change with the rotation speed, but its total sound pressure level increases with the acceleration of the rotation speed.
For rolling ina bearings with large raceway noise, the sound pressure level of raceway noise decreases with the increase of viscosity; For rolling ina bearings with low raceway noise, the sound pressure level changes from decreasing to increasing when the viscosity increases to about 20mm2 / s or more.
The greater the rigidity of rolling ina bearings seat, the lower the total sound pressure level of raceway sound. If the radial clearance is too small, the total sound pressure level and the main frequency of the raceway sound will increase sharply with the reduction of the radial clearance.
The methods to control the noise of the raceway are as follows: select low noise rolling ina bearings, i.e. bearings with small waviness, and carefully select the service conditions. The rolling track noise often affects the noise of the whole machine. Reducing the rolling track noise can reduce the noise of the whole machine.

Impact sound of rolling body and its control method

When a large type of ball rolling ina bearings or cylindrical roller ina inlet bearing operates at low speed under pure radial load, due to the small centrifugal force of the rolling element, the rolling element in the non load area will impact the cage or raceway and make noise. But as the speed increases, the sound will disappear.
The control methods for the impact sound of rolling elements include reducing the radial clearance properly and using rolling ina bearings with cage with reasonable structure and flexible material.

Rolling noise of rolling ina bearings and its control method

The rolling sound is the harsh metal friction sound that can occur in all occasions of cylindrical roller bearings. It mostly occurs in the grease lubricated ina imported bearings of larger models, but it is more likely to occur in the grease with deteriorated base oil performance, and hardly occurs in oil lubrication. In addition, it is easy to occur in winter. When it is subjected to pure radial load, it is easy to occur when the radial clearance is large, and it is easy to occur within a certain speed range with different models, which will occur continuously and intermittently. Special processing methods are adopted for the outer race raceway to prevent the occurrence of rolling noise. If necessary, this bearing can be selected, or the radial clearance of ina imported bearing can be appropriately reduced, and the lubricating grease with excellent performance can be used to improve the rigidity of the parts matched with ina imported bearing.