About SKF rolling bearings and bearing housing knowledge, everyone is familiar with SKF bearings, SKF bearings accounted for 20% of the world's total output of similar products. The standard products offered by SKF have more than 20,000 types of bearings. In addition to SKF rolling bearings, SKF Group also manufactures linear bearings, plain bearings, bearing housings, ball and roller screws, textile machinery components, retaining rings, machine tools and various precision mechanical components. With extensive experience in these areas, he has the knowledge and expertise to develop, manufacture and apply a wide range of advanced engineering products. Here is a brief introduction to SKF rolling bearings and housings:
Housing type: SNL housing, shaft diameter 20-160mm
Options: Double lip seal (TG)
Please read the full instructions of the instructions before starting work:
The installation and disassembly of 1.skf rolling bearings are sometimes involved; the movement of heavy objects, the use of tools and other equipment, or the use of high pressure oil. To avoid accidents, human injury or property damage, please follow the instructions carefully.
2. Make sure the environment is clean.
3. Check the size and shape tolerances of the journal.
4. Check that the surface roughness Ra of the support surface is not more than 12.5 μm. The flatness tolerance should be IT7. For applications with lower requirements, IT8 is available.
If the SKF bearings are mounted on the adapter sleeve, determine the direction of the housing. The nozzle tip of the housing cap should always be on the other side of the adapter nut. Care must be taken in the direction of the entire housing as the top cover and base must be installed in the original orientation.
Determine the direction of the bearing housing on the support surface. Install the anchor bolts but do not tighten them.
Insert half of the split lip seal into the seal groove on both sides of the housing base. The space between the lips of the seal is filled with grease. If the housing is used for the shaft end, insert the end cap on one side instead of the seal.
Install SKF bearings on the shaft; mount directly on the stepped shaft or use an adapter sleeve. Fill the bearing with grease. Add the remaining portion of the recommended grease fill to the sides of the housing base.
Talking about: Spherical roller bearing performance varies with bearing size
The self-aligning function varies with the bearing size series. Generally, the allowable centering angle is 1 to 2.5 degrees. This type of bearing has a large load capacity. In addition to being able to withstand radial loads, the bearing can withstand the axial load of two-way action. It has good impact resistance, and generally the running speed of the spherical roller bearing is low.
Wuxi is one of the largest production centers for spherical rollers in China. The current production capacity is more than 1.5 million sets. The production range is 21304-21320, 22205-22264, 22308-22364, 23022-23064, 23120-23164, and 23218-23264. ,24022-24064,24128-24164, the cage has five kinds of CA, MB, MA, CC, CTN1; the inner ring has two kinds of straight holes and tapered holes (K); the outer ring has W33 (with oil groove), N (with There are two types of stop grooves; there are various clearance standards to meet customer needs; the tolerance levels are P0 and P6.
After years of development and accumulation, the company has strong technical strength and excellent product quality, and is highly praised by domestic and foreign customers. In the domestic market, it covers more than 30 provinces, municipalities and autonomous regions, and is a power machinery, mining machinery, textile machinery, engineering. Machinery, automotive industry and other supporting services.
Its high-tech extension products include long inner ring spherical roller bearings, thrust spherical roller bearings, spherical roller bearings with sealing rings, and vibrating screen bearings. The company also produces joint bearings, rolling mill bearings, and cylindrical rollers. Bearing, cone roller bearing.
Wuxi is one of the largest production centers for spherical rollers in China. The current production capacity is more than 1.5 million sets. The production range is 21304-21320, 22205-22264, 22308-22364, 23022-23064, 23120-23164, and 23218-23264. ,24022-24064,24128-24164, the cage has five kinds of CA, MB, MA, CC, CTN1; the inner ring has two kinds of straight holes and tapered holes (K); the outer ring has W33 (with oil groove), N (with There are two types of stop grooves; there are various clearance standards to meet customer needs; the tolerance levels are P0 and P6.
After years of development and accumulation, the company has strong technical strength and excellent product quality, and is highly praised by domestic and foreign customers. In the domestic market, it covers more than 30 provinces, municipalities and autonomous regions, and is a power machinery, mining machinery, textile machinery, engineering. Machinery, automotive industry and other supporting services.
Its high-tech extension products include long inner ring spherical roller bearings, thrust spherical roller bearings, spherical roller bearings with sealing rings, and vibrating screen bearings. The company also produces joint bearings, rolling mill bearings, and cylindrical rollers. Bearing, cone roller bearing.
For more information and purchase please visit: https://www.supplyforever.com
Common quality defects of bearing parts after heat treatment
Common quality defects of bearing parts after heat treatment include: quenching microstructure overheating, underheating, quenching cracks, insufficient hardness, heat treatment deformation, surface decarburization, soft spots, etc.
Overheat
The microstructure after quenching can be observed from the rough mouth of the bearing part, but the microstructure must be observed to determine the degree of overheating. If coarse needle-shaped martensite appears in the quenched structure of gcr15 steel, it is quenched and superheated. The formation may be caused by excessive overheating of the quenching heating temperature or excessive heating and holding time; or it may be due to the serious banding of the original structure, forming a local martensite needle-like coarseness in the low carbon zone between the two zones. Local overheating caused. The retained austenite increases in the superheated structure, and the dimensional stability decreases. Due to the overheating of the quenched structure, the coarse crystal of the steel causes the toughness of the part to decrease, the impact resistance is lowered, and the life of the bearing is also lowered. Excessive heat can even cause quenching cracks.
2. Underheat
If the quenching temperature is low or the cooling is poor, the tortite structure exceeding the standard is formed in the microstructure, which is called the underheated structure, which lowers the hardness and sharply reduces the wear resistance, which affects the bearing life.
3. Quenching crack
The crack formed by the internal stress of the bearing part during the quenching and cooling process is called quenching crack. The causes of such cracks are: due to excessive heating temperature of quenching or too rapid cooling, the microstructure stress when the thermal stress and metal mass volume change is greater than the fracture strength of the steel; the original defects of the working surface (such as surface micro cracks or scratches) Trace) or steel internal defects (such as slag inclusions, severe non-metallic inclusions, white spots, shrinkage residuals, etc.) form stress concentration during quenching; severe surface decarburization and carbide segregation; insufficient tempering after quenching of parts Or not tempered in time; the cold punching stress caused by the previous process is too large, forging and folding, deep turning tool marks, sharp edges and corners of the oil groove. In short, the cause of quenching crack may be one or more of the above factors, and the existence of internal stress is the main reason for the formation of quenching cracks. The quenching crack is deep and slender, the fracture is straight, and the fractured surface has no oxidation color. It tends to be a longitudinal straight crack or annular crack on the bearing ring; the shape on the bearing steel ball is s-shaped, t-shaped or ring-shaped. The microstructure of the quenching crack is that there is no decarburization on both sides of the crack, and the difference is obvious with forging cracks and material cracks.
Overheat
The microstructure after quenching can be observed from the rough mouth of the bearing part, but the microstructure must be observed to determine the degree of overheating. If coarse needle-shaped martensite appears in the quenched structure of gcr15 steel, it is quenched and superheated. The formation may be caused by excessive overheating of the quenching heating temperature or excessive heating and holding time; or it may be due to the serious banding of the original structure, forming a local martensite needle-like coarseness in the low carbon zone between the two zones. Local overheating caused. The retained austenite increases in the superheated structure, and the dimensional stability decreases. Due to the overheating of the quenched structure, the coarse crystal of the steel causes the toughness of the part to decrease, the impact resistance is lowered, and the life of the bearing is also lowered. Excessive heat can even cause quenching cracks.
2. Underheat
If the quenching temperature is low or the cooling is poor, the tortite structure exceeding the standard is formed in the microstructure, which is called the underheated structure, which lowers the hardness and sharply reduces the wear resistance, which affects the bearing life.
3. Quenching crack
The crack formed by the internal stress of the bearing part during the quenching and cooling process is called quenching crack. The causes of such cracks are: due to excessive heating temperature of quenching or too rapid cooling, the microstructure stress when the thermal stress and metal mass volume change is greater than the fracture strength of the steel; the original defects of the working surface (such as surface micro cracks or scratches) Trace) or steel internal defects (such as slag inclusions, severe non-metallic inclusions, white spots, shrinkage residuals, etc.) form stress concentration during quenching; severe surface decarburization and carbide segregation; insufficient tempering after quenching of parts Or not tempered in time; the cold punching stress caused by the previous process is too large, forging and folding, deep turning tool marks, sharp edges and corners of the oil groove. In short, the cause of quenching crack may be one or more of the above factors, and the existence of internal stress is the main reason for the formation of quenching cracks. The quenching crack is deep and slender, the fracture is straight, and the fractured surface has no oxidation color. It tends to be a longitudinal straight crack or annular crack on the bearing ring; the shape on the bearing steel ball is s-shaped, t-shaped or ring-shaped. The microstructure of the quenching crack is that there is no decarburization on both sides of the crack, and the difference is obvious with forging cracks and material cracks.
For more information and purchase please visit: https://www.supplyforever.com
6 features of sliding bearing damage
As the world's top bearing imported bearings, such as SKF, NSK and other bearing applications are very extensive. In every industry, the characteristics of its damage are also different. Today we look at the damage characteristics of the engine sliding bearing.
(1) Mechanical damage
The mechanical damage of the sliding bearing means that the alloy surface of the bearing bush has different degrees of groove marks. In severe cases, metal peeling occurs on the contact surface and a large area of random scratches occurs; in general, the contact surface damage and ablation phenomenon exist simultaneously. The main cause of mechanical damage to the bearing is that it is difficult to form an oil film on the bearing surface or the oil film is seriously damaged.
(2), bearing cave erosion
Under the repeated action of the sliding bearing in the cylinder pressure impact load, the surface layer is plastically deformed and hardened by hardening, and the local deformation loss ability is gradually formed, and the grain is gradually formed and expanded continuously. Then, as the wear debris falls off, a hole is formed in the loaded surface layer. . Generally, when cavitation occurs in the bearing bush, the pit first appears, and then the pit gradually expands and causes cracking at the interface of the alloy layer, and the crack spreads in the parallel direction of the interface until peeling off. The main reason for the cavitation of the sliding bearing is that the oil flow is strongly disturbed due to the sudden change of the cross section of the structural elements such as the oil groove and the oil hole, and bubbles are formed in the vacuum region where the oil flow is disordered, and then the bubble collapses due to the pressure rise. eclipse. Cavitation is generally found in the high load area of the bearing, such as the lower bearing of the main bearing of the crankshaft.
(3), fatigue pitting
Bearing fatigue pitting refers to the overheating of the bearing and the excessive bearing clearance due to over-loading of the engine, resulting in fatigue damage, fatigue pitting or fatigue shedding in the middle of the bearing. Most of this damage is caused by overload, excessive bearing clearance, or unclean lubricating oil and foreign matter mixed in the interior. Therefore, when using, care should be taken to avoid overloading the bearing. Do not operate at too low or too high speed; adjust the engine to a steady state when idling; ensure normal bearing clearance and prevent engine speed from being too high or too low; check and adjust cooling The working condition of the system ensures that the working temperature of the engine is suitable.
(4), bearing alloy corrosion
The corrosion of the bearing alloy is generally that the lubricating oil is not pure. The chemical impurities (acid oxides, etc.) in the lubricating oil cause the bearing alloy to oxidize to form an acidic substance, causing the bearing alloy to partially fall off and form irregular micro holes or small concaves. pit. The main reason for the corrosion of the bearing alloy is improper selection of lubricating oil, poor corrosion resistance of the bearing material, or rough engine operation and high temperature.
(5), bearing burning
There is a slight convex metal surface between the journal and the bearing friction pair, which forms a local high temperature. In the case of insufficient lubrication and poor cooling, the bearing alloy is blackened or partially melted. This fault is often caused by the over-tightening of the journal and the bearing; the insufficient pressure of the lubricating oil can easily cause the bearing to burn out.
(6), bearing the outer circle
The outer circle of the bearing is the relative rotation of the bearing in the seat hole. After the bearing goes out of the circle, it not only affects the heat dissipation of the bearing, but also causes the alloy on the inner surface of the bearing to ablate, and it also damages the back of the bearing and burns the bearing in severe cases. The main reason is that the bearings are too short, the crown is damaged, the processing or installation does not meet the specifications.
(1) Mechanical damage
The mechanical damage of the sliding bearing means that the alloy surface of the bearing bush has different degrees of groove marks. In severe cases, metal peeling occurs on the contact surface and a large area of random scratches occurs; in general, the contact surface damage and ablation phenomenon exist simultaneously. The main cause of mechanical damage to the bearing is that it is difficult to form an oil film on the bearing surface or the oil film is seriously damaged.
(2), bearing cave erosion
Under the repeated action of the sliding bearing in the cylinder pressure impact load, the surface layer is plastically deformed and hardened by hardening, and the local deformation loss ability is gradually formed, and the grain is gradually formed and expanded continuously. Then, as the wear debris falls off, a hole is formed in the loaded surface layer. . Generally, when cavitation occurs in the bearing bush, the pit first appears, and then the pit gradually expands and causes cracking at the interface of the alloy layer, and the crack spreads in the parallel direction of the interface until peeling off. The main reason for the cavitation of the sliding bearing is that the oil flow is strongly disturbed due to the sudden change of the cross section of the structural elements such as the oil groove and the oil hole, and bubbles are formed in the vacuum region where the oil flow is disordered, and then the bubble collapses due to the pressure rise. eclipse. Cavitation is generally found in the high load area of the bearing, such as the lower bearing of the main bearing of the crankshaft.
(3), fatigue pitting
Bearing fatigue pitting refers to the overheating of the bearing and the excessive bearing clearance due to over-loading of the engine, resulting in fatigue damage, fatigue pitting or fatigue shedding in the middle of the bearing. Most of this damage is caused by overload, excessive bearing clearance, or unclean lubricating oil and foreign matter mixed in the interior. Therefore, when using, care should be taken to avoid overloading the bearing. Do not operate at too low or too high speed; adjust the engine to a steady state when idling; ensure normal bearing clearance and prevent engine speed from being too high or too low; check and adjust cooling The working condition of the system ensures that the working temperature of the engine is suitable.
(4), bearing alloy corrosion
The corrosion of the bearing alloy is generally that the lubricating oil is not pure. The chemical impurities (acid oxides, etc.) in the lubricating oil cause the bearing alloy to oxidize to form an acidic substance, causing the bearing alloy to partially fall off and form irregular micro holes or small concaves. pit. The main reason for the corrosion of the bearing alloy is improper selection of lubricating oil, poor corrosion resistance of the bearing material, or rough engine operation and high temperature.
(5), bearing burning
There is a slight convex metal surface between the journal and the bearing friction pair, which forms a local high temperature. In the case of insufficient lubrication and poor cooling, the bearing alloy is blackened or partially melted. This fault is often caused by the over-tightening of the journal and the bearing; the insufficient pressure of the lubricating oil can easily cause the bearing to burn out.
(6), bearing the outer circle
The outer circle of the bearing is the relative rotation of the bearing in the seat hole. After the bearing goes out of the circle, it not only affects the heat dissipation of the bearing, but also causes the alloy on the inner surface of the bearing to ablate, and it also damages the back of the bearing and burns the bearing in severe cases. The main reason is that the bearings are too short, the crown is damaged, the processing or installation does not meet the specifications.
For more information and purchase please visit: https://www.supplyforever.com
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