Sliding friction occurs during the operation of sliding bearings; The magnitude of sliding friction force mainly depends on manufacturing accuracy; The magnitude of frictional force in sliding bearings mainly depends on the material of the sliding surface of the bearing. Sliding bearings generally have self-lubricating functions on their working surfaces; Sliding bearings are divided into non-metallic sliding bearings and metallic sliding bearings according to their materials.

Non metallic sliding bearings are mainly made of plastic bearings, which are generally made of high-performance engineering plastics; Professional manufacturers generally have self-lubricating modification technology for engineering plastics, which uses fibers, special lubricants, glass beads, and other materials to enhance the self-lubricating properties of engineering plastics. Then, modified plastics are processed into self-lubricating plastic bearings through injection molding.

The most commonly used metal sliding bearings in the early 21st century are three-layer composite bearings, which are generally made of carbon steel plates as substrates. Through sintering technology, a layer of spherical copper powder is first sintered on the steel plate, and then a layer of PTFE lubricant about 0.03mm is sintered on the copper powder layer; The main function of the middle layer of spherical copper powder is to enhance the bonding strength between the steel plate and PTFE, and of course, it also plays a certain role in bearing and lubricating during operation.

There are many types of sliding bearings:

① According to the direction of load-bearing capacity, it can be divided into two types: radial (centripetal) sliding bearings and thrust (axial) sliding bearings.

② According to the type of lubricant, it can be divided into seven categories: oil lubricated bearings, grease lubricated bearings, water lubricated bearings, gas bearings, solid lubricated bearings, magnetic fluid bearings, and electromagnetic bearings.

③ According to the thickness of the lubricating film, it can be divided into two types: thin film lubricated bearings and thick film lubricated bearings.

④ According to the material of the bearing shell, it can be divided into bronze bearings, cast iron bearings, plastic bearings, gemstone bearings, powder metallurgy bearings, self-lubricating bearings, and oil containing bearings.

⑤ According to the structure of the bearing shell, it can be divided into circular bearings, elliptical bearings, three oil leaf bearings, stepped surface bearings, tilting pad bearings, and foil bearings.

Bearing shells are divided into split and integral structures. In order to improve the friction properties of the bearing surface, one or two layers of anti friction material, commonly known as bearing lining, are often cast on its inner diameter surface. Therefore, there are bimetallic and tri metallic bearing shells for the bearing.

The bearing shell or bearing liner is an important component of sliding bearings, and the materials of the bearing shell and bearing liner are collectively referred to as bearing materials. Due to the direct contact between the bearing shell or bearing liner and the journal, the journal part is generally wear-resistant, so the main failure mode of the bearing shell is wear.

The wear of the bearing shell is directly related to the material of the journal, the material of the bearing shell itself, the lubricant, and the lubrication state. When selecting the bearing shell material, these factors should be comprehensively considered to improve the service life and working performance of the sliding bearing.

The commonly used sliding bearing materials include bearing alloys (also known as Babbitt or white alloys), wear-resistant cast iron, copper based and aluminum based alloys, powder metallurgy materials, plastics, rubber, hardwood and carbon graphite, polytetrafluoroethylene (PTFE, PTFE), modified polyoxymethylene (POM), etc.

Sliding bearings absorb and transmit forces between moving parts, maintaining the position and positioning accuracy of the two parts. In addition, directional motion needs to be converted into rotational motion (such as reciprocating piston engines).

Sliding bearings are in surface contact, so a certain oil film must be maintained between the contact surfaces. Therefore, the following issues should be noted during design:

1. To ensure that the oil film can smoothly enter the friction surface.

2. Oil should enter the bearing from the non bearing surface area.

3. Do not open the full ring oil groove in the middle of the bearing.

4. Like oil tiles, open oil grooves at the joints.

5. To ensure sufficient and reliable oil supply to the oil ring.

6. Do not block the fuel hole.

7. Do not create a stagnant oil zone.

8. Prevent sharp edges and corners that cut off the oil film.

2026 March 4th Week Marginal Product Recommendation

Material Specification Sheet–MG-6:

Material specification sheet – MG-6 is Ball and roller bearing steel according to EN ISO 683-17. Ball and roller bearing steel for balls and rollers of any dimension,rings and discs up to 30mm effective thickness.

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