NEWS

News Center

Picture Name

Shanghai Shang Shaft Bearing Quality Inspection Institute Co., Ltd.

Picture Name

Address: 301 Shangxue Road, Jiading District, Shanghai

[Rising knowledge] Sliding bearing assembly method and technical requirements

2020-06-05 13:53

plain bearingIt is a kind of bearing with sliding friction nature. It is characterized by stable operation, reliable and low noise, and can withstand heavy loads and large impact loads. According to different structural forms, it can be divided into integral type, split type and tile type.

(1) Assembly of integral sliding bearing

Integral sliding bearing, commonly known as shaft sleeve, is also the simplest form of sliding bearing. It is mainly assembled by pressing in and hammering. Hot loading is used in special occasions. Most shaft sleeves are made of copper or cast iron. Care should be taken when assembling. Wooden hammer or hammer pad can be used to hit the shaft. When the interference dimension tolerance is large, press in with a press. Tilting must be prevented regardless of knocking or pressing in. After assembly, the oil groove and oil hole should be in the required position.

Deformed bearings after assembly, the inner hole should be trimmed, smaller size can be used reamer cutting, larger size is used to scrape. At the same time, pay attention to control the fit clearance with the shaft within the tolerance range. In order to prevent the shaft sleeve from rotating during work, the contact surface of the shaft sleeve and the box body is equipped with positioning pins or straddle screws. Because the hardness of the box body and the shaft sleeve material are different, it is easy to make the drill bit biased to the soft material side. The solution is: first, punch the hole with a sample against the hard material side before drilling, and second, use a short drill bit to increase the rigidity of the drill bit during drilling.

(2) Assembly of split bearing

The split bearing, also known as the split bearing, has the characteristics of simple structure and convenient adjustment and disassembly. Two bearing bushes are inserted on the bearing bush, and a gasket is used to adjust a reasonable gap at the joint.

① Assembly of bearing bush and bearing body

The upper and lower bearing bushes must be in good contact with the inner hole of the bearing body. If it does not meet the requirements, use the inner hole of the thick-walled bearing bush as the reference, scrape the back of the bearing bush, and at the same time make the steps at both ends of the bearing bush close to the two ends of the bearing body. Thin-walled shingles only need to make the middle part of the bearing bush about 0.1mm higher than the middle part of the bearing body, and no scraping is required.

② The bearing bush is installed in the bearing body

No displacement is allowed in the radial or axial direction, and the steps at both ends of the bearing bush are usually used to stop and locate or locate the pin.

③ Scraping of bearing bush

The split bearing bush generally uses a matching shaft research point. Generally, the bearing bush is scraped first, and then the upper bearing bush is scraped. In order to improve efficiency, the bearing bush and cover may not be installed when the bearing bush is scraped. When the contact point basically meets the requirements, the upper bearing bush and the upper cover are pressed tightly, and the contact point of the lower bearing bush is further corrected when the upper bearing bush is scraped. The tightness of the shaft can be adjusted by changing the thickness of the gasket as the number of scraping increases. When the bearing cover is fastened, the shaft can rotate easily without obvious clearance, and the contact point meets the requirements and the scraping is completed.

④ Measurement of bearing clearance

 

     The size of the bearing clearance can be adjusted by the shim at the middle part, or it can be obtained by directly trimming the bearing bush. The lead pressing method is usually used to measure the bearing clearance. Take several sections of lead wires with a diameter larger than the bearing clearance and place them on the journal and middle face, then tighten the nut to press the middle face tightly, then unscrew the nut, remove the bearing cover, carefully take out the crushed lead wires, and make the micrometer measure the thickness for each section. The bearing clearance can be known according to the average thickness of the lead wires. The general bearing clearance should be 1.5 ‰-2.5 ‰(mm) of the shaft diameter, and the smaller clearance value should be taken when the diameter is larger. If the shaft diameter is 60mm, the bearing clearance should be between 0.09-0.15mm.