Writer: Eric Bearing Limited
When SKF tapered roller bearings are used, the disassembly and assembly of the bearings is an important part in the maintenance and repair process. In many cases, SKF tapered roller bearings will be seriously damaged if they are installed incorrectly during the installation process. Not available. For example, the small rib of SKF bearing is broken. This type of failure is common in the bearing installation. According to the understanding, Eric Bearing Limited shared the reasons for the small rib fracture caused by improper installation of SKF tapered roller bearings.
1. Analysis of installation failure of SKF tapered roller bearings
During the reinstallation of the SKF tapered roller bearing, a small rib broke and the bearing failed to be used. The tapered roller bearing is composed of an inner ring, an outer ring, a cage and 16 tapered rollers. Among them, the small end rib of the inner ring has continuous and spaced fractures, and the fractured part accounts for about 2/3 of the whole, and the morphology of the fractured position is "serrated".
The fracture position and the fracture direction of the small end rib are basically the same. The cracks develop from the side of the raceway oil groove to the small end face until the fracture. The morphology of the part of the fracture location is the same as the size and morphology of the tapered roller end face. The surface of the fracture site is gray-black, and the fracture is in a radial pattern, conforming to the characteristics of brittle fracture.
The SKF bearing cage has the traces of external force knocking, and the cage is severely deformed along the knocking position, changing from the original round shape to a "drop shape", and at the same time there is a "sag" situation. Except for the above-mentioned abnormalities, the bearing has no other obvious abnormalities. SKF 6308/VA201 bearings online , pls click here :
2. Causes of the small rib fracture of SKF tapered roller bearings
This SKF tapered roller bearing installation method adopts cold installation, using installation tools such as hammers and copper rods to strike the bearing. During the process, the steel rod is lowered on the cage or directly hit the cage with an iron hammer. It is mainly reflected in the improper operation that causes the SKF bearing cage to withstand the abnormal continuous impact of external force, which causes the cage to deform and guide the roller to cause an impact on the small rib of the inner ring. When the small rib exceeds the impact load it can bear, brittleness appears Fracture, causing bearing failure.
3. Common factors for the fracture of small ribs of SKF tapered roller bearings
(1) One of the common factors is caused by the band-like distribution of microscopic pores and carbides of the raw materials.
(2) The second common factor is that the cause of microscopic holes is related to the hot rolling process of bearing steel.
4. The correct installation method of SKF tapered roller bearings
Put the small end of the SKF bearing into the journal first, and install the SKF bearing to the designated position to fix it by tapping the large end face.
According to the bearing size and operating conditions, the current bearing installation mostly adopts two forms: cold installation and hot installation. Cold installation generally uses some auxiliary tools to install the bearing; thermal installation generally uses heating to expand the inner diameter of the bearing.
5. Installation suggestions:
(1) It is recommended that users choose an appropriate assembly method such as cold fitting or hot fitting according to the bearing size and operating conditions when installing the bearing. When cold mounting is used, the mounting sleeve should be used as much as possible to install it, which can effectively avoid the abnormal impact on other positions of the bearing and ensure that the end face and the journal are vertical when the bearing is installed. When sleeve installation cannot be used on site, the copper rod should be placed on the inner ring of the bearing, and the hammer should be symmetrical in the diameter direction and cyclically hammered. Do not use excessive force. At the same time, be careful not to let other positions other than the bearing inner ring bear impact .
(2) Improve the installation skills of the installers and operate in accordance with the correct bearing installation requirements to prevent damage to the bearings caused by operating errors, especially violent operations.