Yantai Bonway Manufacturer

Sleeve bearing

Sleeve bearings are a type of cylindrical bearings, named after a rotating inner cylinder inside. Therefore, they will draw out the oil smeared on the outer sleeve.

Many types of axle systems, such as those on bicycles and vehicles, use ball bearings. Sleeve bearings are a type of sliding bearing, that is, bearings with few moving parts. Many spherical ball bearings have an inner ring lined with smaller balls. Compared with ordinary ball bearings, sleeve bearings have only two moving parts; the outer sleeve and the inner rotating cylinder. They are also called sliding bearings, after the technical term for the outer sleeve. The outer stroke of the sleeve bearing can be integral, separate, or clamped between the two halves. The sleeve bearing can be made of compressed powdered metal, such as bronze or copper. Because of the material from which they are made, this metal is porous under the microscope. When they are coated with lubricating oil on the outside, the oil will be sucked into the lubricated inner cylinder through the holes. In addition to oiling, sleeve bearings can also be lubricated in many ways. Sometimes, molten metal or graphite is used. Some man-made polymers can lubricate moving parts at extremely cold temperatures without jamming. Other sleeve bearings are coated with porous oil hardwood so that the oil is more easily sucked in. Although they are self-lubricating, sleeve bearings often fail due to lack of lubrication. The sleeve bearing may wear on the sleeve until the space is no longer completely cylindrical. This may cause the bearing to shake when moving, which will adversely affect the movement of the mechanism. In other cases, there may not be enough lubricant, or under severe temperature conditions, the lubricant may become viscous. When the lubrication is insufficient, the bearing will stop moving. Due to these problems, sleeve bearings are usually carefully protected against dust and dust with seals. The designer or mechanic needs to carefully consider the position of the sleeve bearing in the machine before use. People criticize them for being more picky than ball bearings, because insufficient lubricating oil will cause them to stop completely instead of completely stopping gradual wear over time. Sleeve bearings are an integral part of many machines used in daily life. Cars, household appliances, fans, and office machinery may all use sleeve bearings.

Sleeve bearings are needle bearings.
『Needle Bearing』
Solid needle roller bearings
The basic structure of the inner ring bearing is the same as that of the NU type cylindrical roller bearing, but due to the use of needle rollers, the volume can be reduced and can withstand large radial loads. The bearing without inner ring needs to use a shaft with appropriate accuracy and hardness. The mounting surface is used as a raceway surface.
Thrust needle roller bearings
Separate bearings are composed of raceway rings, needle rollers and cage components, and can be combined with stamped thin raceway rings (W) or cut thick raceway rings (WS). The non-separable bearing is an integral bearing composed of a raceway ring, needle roller and cage assembly which is processed by precision stamping. This type of bearing can bear unidirectional axial load. Occupies a small space, which is conducive to the compact design of the machine. Most of them only use needle roller and cage components, and use the mounting surface of the shaft and the housing as the raceway surface.

What is the function of the sleeve bearing, and what is the matching of the bearing and the shaft?
The matching of the bearing is divided into the outer ring and the inner hole. The first thing to consider is the main rotation of the outer ring or the main rotation of the inner ring. Generally, the main rotation uses light interference, and the non-main rotation uses the dynamic matching and pressing the end face. Coordination is very particular. Please take a look at the instructions of a famous bearing manufacturer before choosing a fit, because the instructions specify the fit. Do not think that the tighter the fit, the better.

Bearings are an important part of contemporary machinery and equipment. Its main function is to support the mechanical rotating body, reduce the friction coefficient during its movement, and ensure its rotation accuracy.
Bearing parameters:
life
Under a certain load, the number of revolutions or hours the bearing experiences before pitting corrosion is called the sleeve bearing life.
The life of a sleeve bearing is defined by the number of revolutions (or hours of work at a certain speed): the bearing within this life should have preliminary fatigue damage (flaking or defect) on any of its bearing rings or rolling elements. However, no matter in laboratory test or in actual use, it can be clearly seen that the bearing has the same appearance under the same working conditions, but the actual life is very different. In addition, there are several different definitions of bearing "life", one of which is the so-called "working life", which means that the actual life that a bearing can reach before it is damaged is caused by wear and tear, and damage is usually not caused by fatigue, but Caused by wear, corrosion, seal damage, etc.
In order to determine the standard of sleeve bearing life, the bearing life and reliability are linked.
Due to the difference in manufacturing accuracy and material uniformity, even the same batch of bearings of the same material and size, used under the same working conditions, will have different life spans. If the statistical life is 1 unit, the longest relative life is 4 units, the shortest is 0.1-0.2 units, and the ratio of the longest to the shortest life is 20-40 times. 90% of the bearings do not produce pitting corrosion, the number of revolutions or hours experienced is called the bearing rating life.

Rated dynamic load
In order to compare the bearing capacity of the bearing against pitting corrosion, when the rated life of the bearing is specified as one million revolutions (106), the maximum load that can be carried is the basic dynamic load rating, denoted by C.
That is to say, under the action of the rated dynamic load C, the reliability of this kind of bearing working for one million revolutions (106) without pitting failure is 90%. The larger the C, the higher the carrying capacity.
For basic dynamic load rating
1. Radial bearing refers to pure radial load
2. Thrust ball bearing refers to pure axial load
3. The radial thrust bearing refers to the radial component that produces pure radial displacement

Rolling bearing
Rolling bearings are divided into radial bearings and thrust bearings according to the load direction or nominal contact angle they can bear. Among them, radial contact bearings are radial bearings with a nominal contact angle of 0, and radial angular contact bearings are radial bearings with a nominal contact angle greater than 0 to 45. Axial contact bearings are thrust bearings with a nominal contact angle of 90, and thrust angular contact bearings are thrust bearings with a nominal contact angle of more than 45 but less than 90.

According to the shape of the rolling elements, it can be divided into sleeve bearings and roller bearings. Roller bearings are classified according to the types of rollers: cylindrical roller bearings, needle roller bearings, tapered roller bearings and spherical roller bearings.
According to whether it can be adjusted during work, it can be divided into self-aligning bearings-the raceway is spherical, which can adapt to the angular deviation between the axis of the two raceways and angular motion bearings and non-aligning bearings (rigid bearings) ---- Bearings that can resist the angular deviation of the axis between the raceways.
According to the number of rows of rolling elements, it is divided into single row bearings, double row bearings and multi row bearings.
According to whether its parts (rings) can be separated into separable bearings and non-separable bearings.
According to its structure shape (such as with or without filling groove, with or without the shape of inner and outer ring and ferrule, structure of ribs, and even with or without cage, etc.) can also be divided into a variety of structural types.
According to their outer diameter size, they are divided into miniature bearings (<26mm), small bearings (28-55mm), medium and small bearings (60-115), medium and large bearings (120-190mm), large bearings (200-430mm) and special bearings. Large bearings (>440mm).
According to application areas, it is divided into motor bearings, rolling mill bearings, main bearings, etc.
According to materials, it is divided into ceramic bearings, plastic bearings, etc.

Needle roller bearings:
Needle roller bearings are equipped with thin and long rollers (the roller length is 3-10 times the diameter, and the diameter is generally not greater than 5mm), so the radial structure is compact, and its inner diameter and load capacity are the same as other types of bearings. The smallest diameter is especially suitable for supporting structures with restricted radial installation dimensions. Needle roller bearings can be selected as bearings without inner ring or needle roller and cage assemblies according to different applications. At this time, the journal surface and housing that match the bearing The hole surface is directly used as the inner and outer rolling surface of the bearing. To ensure the load capacity and running performance are the same as the bearing with ring, the hardness, machining accuracy and surface quality of the raceway surface of the shaft or housing hole should be combined with the bearing ring. The needle bearing is a bearing unit composed of radial needle roller bearings and thrust bearing components. It has a compact structure and small volume, high rotation accuracy, and can bear a certain axial load while bearing a high radial load. And the product structure is diverse, wide adaptable and easy to install. Combined needle roller bearings are widely used in various mechanical equipment such as machine tools, metallurgical machinery, textile machinery and printing machinery, and can make the mechanical system design very compact and smart.

Bearing material
Features of bearing steel:
1. Contact fatigue strength
Under the action of periodic load, the bearing can easily cause fatigue damage when contacting the surface, that is, cracks and peeling appear, which is an important damage situation of the bearing. Therefore, in order to improve the service life of the bearing, the bearing steel must have a high contact fatigue strength.
2. Wear resistance
During the bearing task, not only rolling friction occurs between the ring, rolling element and the cage, but also sliding friction occurs, so that the bearing parts are constantly worn. In order to increase the wear of bearing parts, maintain bearing accuracy and stability, and extend service life, bearing steel should have good wear resistance.
Three, hardness
Hardness is one of the important qualities of bearing quality, and has an indirect effect on contact fatigue strength, wear resistance, and elastic limit. The hardness of bearing steel under operating conditions must reach HRC61~65, which enables the bearing to achieve higher contact fatigue strength and wear resistance.

Four, anti-rust performance
In order to prevent bearing parts and finished products from being corroded and rusted during processing, storage and use, it is requested that the bearing steel should have good rust resistance.
Five, processing performance
In the production process, bearing parts have to go through many cold and hot processing procedures. In order to meet the small quantity, high efficiency and high quality requirements, the bearing steel should have good processing performance. For example, cold and hot forming performance, cutting performance, hardenability, etc.
In addition to the above-mentioned basic requirements, bearing steel should also meet the requirements of proper chemical composition, average external structure, less non-metallic impurities, external appearance defects conforming to specifications, and external surface decarburization layer not exceeding the regular concentration.

Bearing function:
In terms of its function, it should be support, that is, it is used to support the shaft literally, but this is only part of its function. The essence of support is to be able to bear radial loads. It can also be understood as it is used to fix the shaft. The automatic selection of bearings is included. It is to fix the shaft so that it can only achieve rotation, while controlling its axial and radial movement. The motor cannot work at all without bearings. Because the shaft may move in any direction, and the motor is required to only rotate when it is working. Theoretically speaking, it is impossible to achieve the role of transmission. Not only that, the bearing will also affect the transmission. In order to reduce this effect, good lubrication must be achieved on the bearings of the high-speed shaft. Some bearings are already lubricated, which are called pre-lubricated bearings. Most bearings must have lubricating oil. When running at high speed, friction will not only increase energy consumption, but even more terrible is that it is easy to damage the bearings. The idea of turning sliding friction into rolling friction is one-sided, because there is something called sliding bearings.