Regarding things like bearing shells and thrust bearings

Communicate more with the equipment maintenance staff; take the opportunity to go to the site when there is a chance for inspection

Communicate more with the equipment maintenance staff; take the opportunity to go to the site when there is a chance for inspection

1. For example, in the shaft of a straight-moving vehicle, those with balls at the front and rear ends are called bearings. 2. A thrust bearing is a type of bearing that can counteract axial movement. 3. Front and rear thrust bearings mean that there are thrust bearings at both the front and rear ends of the shaft; they are simply located in different places

This post was last edited by 764970655 on 2018-1-13 at 10:31. Bearings are divided into rolling bearings and sliding bearings. I. The classification of rolling bearings is as follows: 1. Deep groove ball bearings – These are the most representative type of rolling bearing; they have a wide range of applications, can withstand radial loads as well as bidirectional axial loads, and are suitable for high-speed rotation as well as situations where low noise and low vibration are required. Sealed bearings with steel plate dust covers or rubber seals are pre-filled with an appropriate amount of lubricant. Bearings whose outer ring is equipped with a stop ring or flange are easy to position axially and facilitate installation within the housing. The dimensions of maximum-load bearings are the same as those of standard bearings, but the inner and outer rings have filling grooves that increase the number of balls present, thereby raising the rated load. The main types of retainers used are: steel plate stamped retainers (wavy, crown-shaped… single row) ； S-shaped…double-row) brass alloy or phenolic resin-cut retainers, synthetic resin-molded retainers. Primary uses: Automotive: rear wheels, transmissions, components of electrical systems. Electrical: general-purpose motors, household appliances. Others: instruments, internal combustion engines, construction machinery, railway vehicles, handling and lifting equipment, agricultural machinery, various industrial machines. 2. Angular contact ball bearings: There is an angle of contact between the rings and the balls; the standard angles of contact are 15°, 30°, and 40°. The larger the angle of contact, the greater the axial load capacity, while a smaller angle of contact is more suitable for high-speed rotation. Single-row bearings can withstand a combination of radial load and unidirectional axial loads in the DB and DF configurations, while double-row bearings can withstand radial load as well as bidirectional axial loads. The DT combination is suitable for applications with high unidirectional axial loads where the rated load of a single bearing is insufficient. High-speed ACH type bearings have small ball diameters and a large number of balls, and are mostly used in machine tool spindles. Angular contact ball bearings are suitable for high-speed and high-precision rotation. Structurally, it consists of two single-row angular contact ball bearings combined on the back side, sharing the same inner and outer rings, and is capable of withstanding radial loads as well as bidirectional axial loads. Sealed versions are also available for bearings without loading slots; the main types of retainers used are stamped steel retainers (bowl-shaped... single row ； S-shaped, crown-shaped…double row), brass alloy or phenolic resin-made retainers, synthetic resin-molded retainers. Primary uses: Single row: machine tool spindles, high-frequency motors, gas turbines, centrifugal separators, front wheels of compact cars, differential pinion shafts. Double row: oil pumps, Roots blowers, air compressors, various types of transmissions, fuel injection pumps, printing machinery. 3. Four-point contact ball bearings can withstand radial loads as well as bidirectional axial loads. A single such bearing can replace an angular contact ball bearing arranged in a face-to-face or back-to-back configuration, and they are suitable for withstanding pure axial loads or composite loads with a significant axial component. This type of bearing can form one of the contact angles (α) when subjected to axial loads in any direction; therefore, the rings and balls are always in triple-contact at the three points on any contact line. Main applicable retainer: copper alloy cut retainer. Primary uses: jet engines for aircraft, gas turbines. 4. Self-aligning ball bearings have self-aligning capabilities due to the spherical shape of their outer ring raceway, allowing them to automatically adjust for any misalignment caused by the bending or out-of-centering of the shaft or housing. Tapered bore bearings can be easily mounted on the shaft using fasteners. Steel plate-stamped retainers: Chrysanthemum shape…12, 13, 22…2RS, 23…2RS; Sunflower shape…22, 23. Used in woodworking machinery and textile machinery for drive shafts, as well as in vertical seated self-aligning bearings. 5. Cylindrical roller bearings: The cylindrical rollers are in linear contact with the raceways, giving them high radial load capacity; thus they are suitable for withstanding heavy loads and impact forces, as well as for high-speed rotation. The N-type and NU-type bearings allow axial movement, enabling them to adapt to changes in the relative position between the shaft and the housing caused by thermal expansion or installation errors. They are most suitable as free-end bearings. The NJ-type and NF-type bearings can withstand a certain degree of unidirectional axial load, while the NH-type and NUP-type bearings can withstand a certain degree of bidirectional axial load. The inner or outer ring can be separated, facilitating installation and removal. The NNU-type and NN-type bearings have high resistance to radial loads and are mostly used in machine tool spindles. Main types of retainers suitable for use: stamped steel plate retainers (Z-shaped), cut copper alloy retainers, pin retainers, and synthetic resin-molded retainers. Main applications: medium and large motors, generators, internal combustion engines, gas turbines, machine tool spindles, reduction gearboxes, handling and material handling machinery, and various industrial machines. 6. Solid needle roller bearings have a basic structure similar to that of NU-type cylindrical roller bearings, but since needle rollers are used, their size can be reduced, and they are capable of withstanding large radial loads. Unlike bearings with an inner ring, these bearings do not require the mounting surface of the shaft, which must have the appropriate precision and hardness, to be used as the raceway surface. Main applicable retainer: steel plate stamped retainer. Main uses: automobile engines, transmissions, pumps, excavator track wheels, hoists, bridge cranes, compressors. 7. Tapered roller bearings: These bearings are equipped with tapered rollers, which are guided by the large flange on the inner ring. The design ensures that the vertices of the conical surfaces of the inner ring raceway, the outer ring raceway, and the roller rolling surface all intersect at a point on the bearing’s center line. Single-row bearings can withstand radial loads and unidirectional axial loads, while double-row bearings can withstand radial loads and bidirectional axial loads. Suitable for withstanding heavy loads and impact loads. Depending on the contact angle with the chest (α), they are divided into three types: small cone angle, medium cone angle, and large cone angle; the larger the contact angle, the greater the axial load-bearing capacity. The outer ring can be separated from the inner components (the inner ring and the roller and cage assembly), facilitating installation and removal. Bearings with the suffix codes “J” or “JR” possess international interchangeability; these bearings also often use imperial series products, and the common types of retainers used for them are stamped steel retainers, synthetic resin molded retainers, and pin retainers. Primary uses: Automobiles: front wheels, rear wheels, transmission, differential pinion shafts. Machine tool spindles, construction machinery, large-scale agricultural machinery, gear reduction units for railway vehicles, roll necks and reduction units for rolling mills. 8. Self-aligning roller bearings: These bearings have spherical rollers between the spherical race of the outer ring and the double-race inner ring; depending on their internal structure, they are classified into four types: R, RH, RHA, and SR. Since the center of the arc of the outer raceway coincides with the center of the bearing, it possesses self-aligning capabilities, allowing it to automatically adjust any misalignment caused by the bending or out-of-centerness of the shaft or housing. It can withstand radial loads and bidirectional axial loads. In particular, it has a high radial load capacity, making it suitable for withstanding heavy loads and impact loads. Tapered bore bearings can be installed on and removed from the shaft by using fasteners or release sleeves. There are two types of taper for cone holes: 1:30 (auxiliary code: K30)……suitable for the 240 and 241 series; 1:12 (auxiliary code: K)……suitable for other series. Oil holes, oil grooves, and one positioning pin hole can be provided on the outer ring. Oil holes and oil grooves can also be provided on the inner ring. Mainly applicable retainers: copper alloy cut retainers, steel plate stamped retainers, pin-type retainers, and synthetic resin molded retainers. Main uses: papermaking machinery, reduction gears, railway vehicle axles, gearbox housings for rolling mills, roller tables in rolling mills, crushers, vibrating screens, printing machinery, woodworking machinery, various industrial reduction gears, vertical self-aligning bearings. 9. Thrust ball bearings consist of a washer-shaped race ring with races, along with balls and a retainer assembly. The race ring that fits with the shaft is called the shaft ring, while the race ring that fits with the housing is called the seat ring. A bidirectional bearing connects the middle ring and the shaft. A single-direction bearing can withstand axial loads in one direction, while a double-direction bearing can withstand axial loads in both directions (neither of them can withstand radial loads). Mainly applicable retainers: steel plate stamped retainers, copper alloy or phenolic resin cut retainers, synthetic resin molded retainers. Primary uses: automobile steering pins, machine tool spindles. 10. Thrust cylindrical roller bearings consist of washer-shaped race rings (shaft ring, seat ring) together with cylindrical rollers and a cage assembly. The cylindrical rollers are machined with a convex surface, resulting in a uniform pressure distribution between the rollers and the raceway surfaces, allowing them to withstand unidirectional axial loads. It has a high axial load capacity and strong axial stiffness as well. Main suitable retainers: Copper alloy cut retainers. Main applications: Oil drilling rigs, iron and steel manufacturing machinery. 11. Thrust needle bearings: These separate-type bearings consist of a race ring along with needle and retainer assemblies, and can be combined with either stamped thin race rings (W) or cut thick race rings (WS). A non-separable bearing is an integrated type of bearing consisting of a raceway ring that has been precision-stamped, along with needle rollers and a retainer assembly; it can withstand unidirectional axial loads. These types of bearings take up little space, which facilitates a compact design of machinery. Most use only needle and cage assemblies, with the mounting surfaces of the shaft and housing serving as the raceway surfaces. Main types of retainers suitable for use: stamped steel retainers, synthetic resin-molded retainers. Main applications: transmission systems in automobiles, tractors, machine tools, etc. 12. Thrust tapered roller bearings: These bearings use frustum-shaped rollers (with the larger end being spherical); the rollers are precisely guided by the ribs on the raceway rings (axial ring and seat ring). The design ensures that the vertices of the conical surfaces on the raceway surfaces of the axial ring and seat ring, as well as on the rolling surface of the rollers, all intersect at a point on the axis of the bearing. Single-direction bearings can withstand axial loads in one direction, while double-direction bearings can withstand axial loads in both directions. The double-direction bearing connects the middle ring to the shaft; however, due to the use of a clearance fit, it is necessary to use sleeves or similar elements to axially position the middle ring. The main type of retainer used is a copper alloy cut retainer. Primary uses: Unidirectional: crane hooks, rotary tables in oil drilling rigs. Bidirectional: roll necks in steel rolling mills. 13. Thrust self-aligning roller bearings: In these bearings, the spherical rollers are arranged at an angle; due to the spherical shape of the raceway surfaces, they possess self-aligning capabilities, which allows the shaft to tilt to a certain extent. They have a very high capacity to bear axial loads, and can also withstand some radial loads while carrying axial loads. Oil lubrication is generally used during operation. Main applicable retainers: copper alloy cut retainers. Main uses: hydrogenerators, vertical electric motors, propeller shafts for ships, reducers for rolling screws in steel rolling mills, tower cranes, coal crushers, extruders, shaping machines

This post was last edited by 764970655 on 2018-1-13 at 10:11. II. There are many types of sliding bearings. ①Based on the direction of the load they can withstand, they can be divided into two categories: radial (centripetal) sliding bearings and thrust (axial) sliding bearings. ②Based on the type of lubricant, bearings can be classified into 7 categories: oil-lubricated bearings, grease-lubricated bearings, water-lubricated bearings, gas bearings, solid-lubricated bearings, magnetohydrodynamic bearings, and electromagnetic bearings. ③Based on the thickness of the lubrication film, bearings can be divided into two categories: thin-film lubricated bearings and thick-film lubricated bearings. ④Based on the material of the bearing bush, they can be classified into bronze bearings, cast iron bearings, plastic bearings, gemstone bearings, powder metallurgy bearings, self-lubricating bearings, and oil-impregnated bearings, among others. ⑤Based on the structure of the bearing shells, they can be classified into circular bearings, elliptical bearings, three-lip bearings, stepped-face bearings, tilting-pad bearings, and foil bearings, among others. Bearing shells are divided into split and integral structures. To improve the friction properties of the bearing shell surface, one or two layers of friction-reducing material are often cast on its inner diameter surface; this material is commonly referred to as a bearing lining. Therefore, bearing shells are also classified as bimetallic bearing shells and trimetallic bearing shells. Bearing shells or bearing bushes are important components of sliding bearings, and the materials used for these bearing shells and bushes are collectively referred to as bearing materials. Since the bearing shells or bushings are in direct contact with the shaft journals, the shaft journal parts are generally quite wear-resistant; therefore, the main mode of failure for bearing shells is wear. The wear of bearing shells is directly related to the material of the shaft journal, the material of the bearing shells themselves, the lubricant, and the lubrication conditions. When selecting the material for bearing shells, these factors must be taken into account to improve the service life and performance of sliding bearings.