The purpose and method of rolling bearing lubrication1

The purpose of rolling bearing lubrication:

1. Reduce friction and wear: in the mutual contact part of the ring, rolling body and cage that constitute the bearing, prevent metal contact and reduce friction and wear.

2. Extend the fatigue life: the rolling fatigue life of the bearing will be extended when the rolling contact surface is well lubricated during rotation. Conversely, if the oil viscosity is low and the lubricating oil film thickness is not good, it will be shortened.

3. Discharge frictional heat and cooling: the circulating oil supply method can use oil to discharge the heat generated by friction, or the heat from the outside, and cool it. Prevent the bearing from overheating and prevent the aging of the lubricating oil itself.

4. Others: It also has the effect of preventing foreign matter from invading the inside of the bearing, or preventing rust and corrosion.

Lubrication method:

At present, the lubrication methods of bearings mainly include grease lubrication and oil lubrication. In order to make the bearing function well, first of all, it is necessary to choose suitable Lubrication method for conditions and purpose of use. If only lubrication is considered, the lubricity of oil lubrication is dominant. However, grease lubrication has the advantage of simplifying the structure around the bearing. Compare the advantages and disadvantages of grease lubrication and oil lubrication.

Bearing installation:

Whether the bearing is installed correctly affects the accuracy, life and performance. Therefore, the design and assembly department should fully study the bearing installation. It is hoped that the installation will be carried out according to the working standard. The items of the work standard are usually as follows:

(1) Clean the bearing and bearing related parts;

(2) Check the size and finishing of the related parts;

(3) Installation;

(4) Inspection after the bearing is installed;

(5) Supply lubricant.

It is hoped that the bearing will be unpacked just before installation. General grease lubrication, no cleaning, direct filling with grease. Lubricating oil does not need to be cleaned in general. However, bearings for instruments or high-speed use should be cleaned with clean oil to remove the rust inhibitor coated on the bearings. Bearings with rust inhibitor removed are easy to rust, so they cannot be left unattended. Furthermore, bearings that have been sealed with grease can be used directly without cleaning.

The installation method of the bearing varies according to the bearing structure, fit and conditions. Generally, the inner ring needs an interference fit due to the shaft rotation. Cylindrical bore bearings are usually pressed in by a press, or by a shrink-fit method. In the case of a tapered hole, install it directly on the tapered shaft, or install it with a sleeve.

When installing to the shell, generally there is a lot of clearance fit, and the outer ring has an interference amount, which is usually pressed in by a press, or there is a shrink fit method for installation after cooling. When dry ice is used as a coolant and shrink fit is used for installation, moisture in the air will condense on the surface of the bearing. Therefore, appropriate anti-rust measures are required.