Bearings are an important part of contemporary machinery, and their quality is related to the operation of the entire equipment. This article describes the installation, maintenance, disassembly and common problems of the bearings, and hopes to help everyone’s production.

Bearing installation

The installation of the bearing directly affects the accuracy, life and performance. Therefore, the design and assembly department should fully study the installation of the bearing, according to the following operating standards:

(1) cleaning the bearing and bearing related parts;

(2) Check the size and finishing of the associated components;

(3) Installation (only before the installation, only open the bearing packaging);

(4) Inspection after installation of the bearing;

(5) Supply lubricant.

Generally grease is lubricated, not cleaned, and directly filled with grease. Lubricating oil is not necessary for cleaning. However, for instruments or high-speed bearings, it should be cleaned with clean oil to remove the rust inhibitor applied to the bearing. The bearing with the rust preventive removed, it is easy to rust, so it can not be placed. Furthermore, bearings that have been sealed with grease are used without cleaning.

The mounting method of the bearing varies depending on the bearing structure and the fit. In general, the inner ring requires an interference fit because it is mostly a shaft rotation. Cylindrical bore bearings, press with a press, or use a hot charging method. For taper holes, mount directly on the taper shaft or with a sleeve.

(1) Method of pressing in with a press

Small bearings are widely used in press presses. The pad is placed in the inner ring and pressed tightly to the inner ring with a press to closely contact the shaft shoulder. Installing the inner ring on the outer ring pad is the cause of the indentation and crushing on the raceway, so it must be absolutely prohibited.

When operating, oil can be applied to the mating surface in advance. If you have to use a hammer to knock on the installation, you should put a block on the inner ring. This practice is limited to situations where the amount of interference is small and cannot be used for large interference or medium and large bearings.

For non-separable bearings such as deep groove ball bearings, where the inner ring and the outer ring need to be installed with interference, use the pad pad and use the screw or oil pressure to press the inner ring and the outer ring at the same time. The outer ring of the self-aligning ball bearing is easy to tilt, and even if it is not an interference fit, it is better to install the pad.

For separate bearings such as cylindrical roller bearings and tapered roller bearings, the inner and outer rings can be mounted on the shaft and the outer casing respectively. When the inner and outer rings are respectively assembled, the key is to stabilize. The two are closed together so that the center of the two does not deviate, and the press-in will cause the raceway surface to be stuck.

(2) Method of hot charging

Large bearings require a lot of force when pressed in, so it is difficult to press in. Therefore, the method of heating the bearing in the oil to expand it and then attaching it to the shaft is widely used. With this method, it is possible to complete the work in a short time without adding undue force to the bearing.

The heating temperature of the bearing is based on the bearing size and the required interference. The precautions for hot loading operations are as follows:

(a) Do not heat the bearing to above 120 °C;

(b) In order to prevent the bearing from directly contacting the bottom of the oil tank, it may be considered to place the bearing on the metal net or to lift the bearing;

(c) Heating the bearing to a temperature 20 ° C to 30 ° C higher than the required temperature so that the inner ring does not become cold during operation and is difficult to install;

(d) After installation, the bearing is cooled down and the width direction is also contracted, so use a shaft nut or other suitable method to tighten it to prevent a gap between the inner ring and the bearing shoulder.