What are the preloading methods for rolling bearings?

Preloading methods of rolling bearings are divided into radial preloading method and axial preloading method

1. The radial preloading method and the radial jacking method are mostly used in the tapered bore bearing bearing bearing bearing under radial load, and the typical example is the double row precision short cylindrical roller bearing. The axial position of the bearing relative to the tapered journal is adjusted by the nut, so that the inner ring has a suitable expansion amount and the radial negative clearance is obtained. This method is often used in machine tool spindles and jet engines.

2. Axial preloading method axial preloading method can be divided into positioning preloading and constant pressure preloading. In the positioning preloading, the appropriate preload can be obtained by adjusting the size of bushing or gasket; the appropriate preload can also be obtained by measuring or controlling the starting friction moment; the preloading purpose can also be achieved by directly using the pair of double bearings with pre adjusted preload, at this time, the user does not need to adjust again. In a word, the relative position of bearings that have been preloaded axially will not change when they are used.

Constant pressure preloading is a proper preloading method for bearings by means of spiral spring and disc spring. Generally, the rigidity of the preloading spring is much smaller than that of the bearing, so the relative position of the bearing with constant pressure preloading will change in use, but the amount of preloading is roughly unchanged.

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

(1) When the preload is equal, the effect of positioning preload on the increase of bearing rigidity is greater, and the effect of rigidity change on bearing load is much smaller.

(2) In the use of positioning preloading, the axial length difference caused by the temperature difference between the shaft and the 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 preloading; while in the use of constant pressure preloading, the change of Preloading can be ignored.

How to install zero bearing?

Class 0 bearing is the old standard, according to the new standard is class 6, namely deep groove ball bearing. By "installation", you mean to assemble the parts of the bearing into a set of bearings, or to install the bearings on the machine tool. The assembly of deep groove ball bearing is shown in the figure

There are many ways to install the bearing on the machine tool, such as manual installation, mechanical pressing and so on.

Manual installation of rolling bearing:

Assembly of bearing inner ring and shaft - for open bearing (i.e. unsealed bearing), heat the bearing to 6 or 70 degrees, let the inner hole expand, put on gloves, and push the bearing into the bearing gear of the shaft by hand. The heating of bearings can be carried out in a special heater or clean engine oil.

Installation without heating: use one end of the copper bar against the end face of the inner ring, gently hammer the other end of the copper bar, then change to the symmetrical position, and then hammer until the bearing enters the specified position. During the whole process, the copper bar shall not touch the outer ring of the bearing, and no foreign matters (such as copper chips) shall fall into the bearing. Assembly of bearing outer ring and hole - as mentioned above, only the striking object is bearing outer ring. Similarly, the copper bar shall not touch the inner ring of the bearing, and no foreign matter shall fall into the bearing.