Deep groove ball bearings:
Basic Parameters
Deep groove ball bearings are a common type of rolling bearing. They consist of an outer ring, an inner ring, a set of steel balls, and a set of retainers. There are two types of deep groove ball bearings: single row and double row. The deep groove ball structure also comes in two configurations: sealed and open. Open refers to bearings without a sealing structure. Sealed deep groove ball bearings are divided into dustproof sealed and oilproof sealed. The dustproof sealed cover is made of steel plate stamping and serves only to prevent dust from entering the bearing raceway. The oilproof type is a contact seal, effectively preventing the grease within the bearing from溢出.
Single-row deep groove ball bearing type is represented by 6, and double-row deep groove ball bearing by 4. It features a simple structure, ease of use, and is a widely used type of bearing with broad application.
Working Principle
Deep groove ball bearings mainly bear radial loads and can also bear both radial and axial loads simultaneously. When they only bear radial loads, the contact angle is zero. When deep groove ball bearings have a larger radial clearance, they exhibit the performance of a "blank" angular contact bearing, capable of withstanding greater axial loads. The friction coefficient of deep groove ball bearings is very low, and their maximum speed is also very high.
Bearing characteristics
Tapered roller bearings are representative rolling bearings with wide applications. They are suitable for high-speed operations, even at very high speeds, and are highly durable, requiring minimal maintenance. These bearings have a low friction coefficient, high maximum speed, simple structure, low manufacturing costs, and are easy to achieve high manufacturing precision. The range of sizes and shapes is diverse, and they are used in precision instruments, low-noise motors, automobiles, motorcycles, and general machinery industries. They are one of the most widely used types of bearings in the mechanical industry, primarily supporting radial loads but also capable of handling a certain amount of axial loads.
When selecting a larger radial clearance, the axial load-bearing capacity increases, and the contact angle is zero when bearing pure radial force. When subjected to an axial force, the contact angle is greater than zero. Generally, pressed wave-shaped retainer is used, followed by turned solid retainer, and nylon frame is sometimes adopted as well.
Mounted on the shaft, the deep groove ball bearings can limit the axial displacement of the shaft or housing in both directions within the axial clearance range of the bearing, thus allowing for双向axial positioning. Additionally, these bearings possess a certain amount of self-aligning capability; they can still function normally when tilted 2′ to 10′ relative to the housing bore, although this may affect the bearing's lifespan. The retainers for deep groove ball bearings are typically stamped steel sheet wave retainers, while larger bearings often use turned metal solid retainers.
Taper roller bearings are commonly used rolling bearings. They feature a simple structure and easy operation. Mainly used to bear radial loads, but with increased radial clearance of the bearing, they also exhibit certain properties of angular contact ball bearings, allowing them to bear combined radial and axial loads. They can also bear pure axial loads when high rotational speeds are required and thrust ball bearings are not suitable. Compared to other types of bearings with the same specifications as the taper roller bearing, this type has a lower friction coefficient and a higher maximum speed. However, it is not resistant to impact and is not suitable for bearing heavy loads.
Bearings construction
Deep groove ball bearings have a simple structure, are easy to achieve high manufacturing precision compared to other types, and are therefore suitable for mass production in series at a lower cost, making them extremely common. In addition to the basic type, there are various modified structures, such as deep groove ball bearings with dust covers, deep groove ball bearings with rubber sealing rings, deep groove ball bearings with locking grooves, deep groove ball bearings with ball insertion slots for high load capacity, and double-row deep groove ball bearings.
Bearings Type
Single-row deep groove ball bearing
2. Single-row deep groove ball bearing with dust cover
3. Single-row deep groove ball bearings with dust cover and sealing ring
4. Single-row deep groove ball bearing with stop slots and stop rings on the outer ring
5. Deep groove ball bearing with ball seat groove
6. Double Row Deep Groove Ball Bearings
According to the size and dimensions, deep groove ball bearings can be categorized as:
(1) Miniature Bearings - Bearings with a nominal outer diameter of 26mm or less.
(2) Small Bearings - Bearings with nominal outer diameter sizes ranging from 28 to 55mm.
(3) Small and Medium-sized Bearings —— Bearings with nominal outer diameter sizes ranging from 60 to 115mm.
Medium to Large Bearings —— Bearings with nominal outer diameter sizes ranging from 120 to 190mm
(5) Large Bearings - Bearings with nominal outer diameter sizes ranging from 200 to 430mm.
(6) Extra-large Bearings - Bearings with nominal outer diameter sizes of 440mm and above.
Deep groove ball bearings are used in gearboxes, instruments and meters, motors, household appliances, internal combustion engines, vehicles, agricultural machinery, construction equipment, engineering machinery, roller skates, yo-yos, and more.
Installation Method
Deep groove ball bearing installation method one: Press fit: When the inner race of the bearing is a tight fit with the shaft and the outer race is a loose fit with the bearing housing bore, the bearing can be pressed onto the shaft first using a press machine. Then, the shaft with the bearing attached is inserted into the bearing housing bore. During the press fit, place a soft metal tube (copper or soft steel) made of a soft metal on the inner race end face of the "_blank" bearing. When the outer race is a tight fit with the bearing housing bore and the inner race is a loose fit with the shaft, the bearing can be pressed into the bearing housing bore first. At this point, the outer diameter of the installation tube should be slightly smaller than the diameter of the bore. If both the bearing rings and the shaft and the bore are tight fits, both the inner and outer races must be pressed into the shaft and the bore simultaneously. The structure of the installation tube should be able to simultaneously press the end faces of both the inner and outer races of the bearing.
Deep Groove Ball Bearing Installation Method Two: Heat Fit: An installation method that utilizes thermal expansion to convert a tight fit into a loose fit by heating the bearing or bearing housing. It is a commonly used and labor-saving method. This method is suitable for installing bearings with large interference fit. Before heating, place the bearing or the sleeve of a separable bearing into an oil tank and uniformly heat it to 80-100°C. Then, remove it from the oil and quickly install it onto the shaft. To prevent the inner ring end face and the shaft shoulder from not fitting tightly after cooling, the bearing can be further tightened axially after cooling. When the outer race of the bearing is tightly fitted to a lightweight metal bearing housing, use the heat fit method for the bearing housing to avoid any scratches on the fitting surface. When heating the bearing in an oil tank, there should be a grate at a certain distance from the bottom of the tank or use hooks to hang the bearing, ensuring it doesn't touch the bottom to prevent impurities from entering the bearing or uneven heating. An oil thermometer must be present in the oil tank to strictly control the oil temperature to no more than 100°C, to prevent tempering effects that may reduce the hardness of the sleeve.
Tolerance
Standard deep groove ball bearings feature normal grade, all conforming to GB307.1.
Clearance space
Standard deep groove ball bearings are available in C2, standard (CN), C3, C4, and C5 internal clearance grades, all conforming to GB4604.
Retaining rack
Deep groove ball bearings usually employ steel stamping retainers or brass solid retainers. For outer diameters less than 400mm, steel stamping retainers are used without a suffix code. For outer diameters greater than 400mm, brass solid retainers are more commonly used without a suffix code.
Three types of bearing processing methods
The processing methods for deep groove ball bearing components are as follows:
1. Multi-process manufacturing: Generally, bearing production requires 20 to 40 processes, with some exceeding 70.
2. Forming Processing: The working surfaces of bearing parts are all rotatable forming surfaces, suitable for processing by the forming method.
3. Precision Machining: Most bearing parts require grinding processing, with both the grinding dimensions and geometric accuracy measured in micrometers (μm).
Deep groove ball bearings, when the bearing load is too low during operation, can cause sliding between the balls and raceways, leading to abrasion. This tendency is particularly pronounced in large deep groove ball bearings with heavy balls and retainers. It is anticipated that there may be cases of insufficient load during use. Please contact the relevant personnel promptly when selecting bearings!
Causes of Rust Formation
In many cases, bearings may suffer from rusting, and there are various reasons for bearing rust. The main factors we commonly encounter in our daily lives include the following.
1) Due to poor sealing, intrusion by moisture, dirt, etc.
2) Bearings have been unused for an extended period, exceeding the anti-rust period, and lack proper maintenance.
3) The metal surface has a high degree of roughness.
4) Exposure to corrosive chemicals, insufficient cleaning of bearings, surface contamination, or contact with sweat on the bearings; failure to package or install the bearings promptly after cleaning, leading to long-term exposure to air and moisture, resulting in corrosion and contamination.
5) Environmental temperature and humidity, as well as contact with various environmental media; rust preventive agent failure or non-compliance with quality requirements.
Suffix meaning for deep groove ball
1. CN: Standard radial clearance; typically used in combination with the following letters to indicate a narrower or offset clearance range.
H: Narrowed clearance range, equivalent to the upper half of the original clearance range
Narrowed clearance range, equivalent to the lower half of the original clearance range
Offset gap range, equivalent to the upper half of the original gap range and the lower half of the next gap range. The above letters also apply to the following gap groups to form corresponding meanings: C2, C3, C4, and C5, for example, C2
C2: Radial Clearance Less Than Standard Group
2. C3: Radial Clearance Larger Than Standard Group
3. C4: Radial Clearance greater than C3
4. C5: Radial Clearance Larger Than C4
5. DB: Pair of single row deep groove ball bearings paired in back-to-back configuration
6. DF: Two single-row deep groove ball bearings matched face-to-face
7. DT: Single-row deep groove ball bearings paired in series
8. E: Reinforced Design
9. GJN: Polyurea grease, NLGI Grade 2, temperature range -30 to +150°C (standard fill quantity)
10. GXN: Polyurea grease, NLGI 2 consistency, temperature range -40 to +150°C (standard filling amount)
11. J: Stampings steel retaining bracket
12. LHT23: Lithium-based grease, NLGI Grade 2, temperature range -50 to +140°C (standard filling quantity)
13. LT: Lithium-based Grease, NLGI Grade 2, Temperature Range -55 to +110°C (Standard Filling Quantity)
14. LT10: Lithium-based grease, NLGI Grade 2, temperature range -50 to +90°C (standard filling capacity)
15. M: Machined brass retaining bracket, steel ball guide. Different designs and materials are identified by numbers added after M, such as M2
16. MA: Machined Brass Retainer, Outer Ring Guide
17. MB: Machined Brass Retainer, Inner Ring Guide
18. MT33: Lithium-based Grease, NLGI Consistency 3, Temperature Range -30 to +120°C (Standard Filling Quantity)
20. N: Outer ring with stop slot
21. NR: Outer ring with stop groove and stop ring
22. N1: The outer side has grooves (for配合with the stop device to prevent the outer ring from rotating)
23. P5: Dimensional and rotational accuracy conforms to ISO tolerance grade 5
24. P6: Dimensional accuracy and rotational accuracy meet ISO tolerance grade 6
25. P52：P5+C2
26. P62：P6+C2
27. P63：P6+C3
28. RS1: Nitrile Butadiene Rubber (NBR) Contact Seal with Steel Reinforcement on One Side
29. RSH: Contact Sealing Ring of Nitrile Butadiene Rubber (NBR) with Steel Skeleton on One Side
30. RSL: Low-friction NBR (Nitrile Butadiene Rubber) seals with steel reinforcing on one side
31. RZ: Low-friction NBR (Nitrile Butadiene Rubber) seals with steel reinforced frame on one side
32. TH: Fiber-reinforced phenolic resin keeper (card type)
33. TN: Injection Molding Nylon Retainer Bracket
34. TN9: Injection molded glass fiber reinforced nylon 6,6 retainer
35. VL0241: Outer surface of the outer ring coated with alumina, insulation capability up to 1000VDC
36. VL2071: Inner ring outer surface with alumina coating, insulation capability up to 1000VDC
37. WT: Polyurea grease, NLGI Grade 2, temperature range -40 to +160°C (standard filling quantity)
38. Y: Stamped copper retainer
39. Z: Dust cover with stamped steel on one side
40. ZNR: Outer ring with stop slots and stop rings, with a stamped steel dust cover on the other side of the stop slots
41. 2RS1: Contact seal circlips with steel inserts for nitrile rubber (NBR) with side bands
42. 2RSH: Contact Seal Washers with Steel Reinforcement on Both Sides, Nitrile Rubber (NBR)
43. 2RSL: NBR low-friction seal rings with steel skeletons on both sides
44. 2RZ: NBR low-friction sealing rings with steel reinforcing on both sides
45. 2Z: Dust covers with stamped steel on both sides
46. 2ZNR: Outer ring with stop slots and stop rings, with stamped steel dust covers on both sides
Common suffixes for ball gap with packaging:
1. C3: Radial Clearance Larger Than Standard Group
2. N: Outer ring with stop slot
3. NR: Outer ring with stop slot and stop ring
4. Z: Dust cover with stamped steel on one side
5. ZNR: Outer ring with stop slot and stop ring, the other side of the stop slot features a stamped steel dust cover.
6. 2Z: Dust caps with stamped steel on both sides
7. 2ZNR: Outer ring with stop slots and stop rings, with stamped steel dust covers on both sides
The meaning of the suffix for stainless steel:
1. R: Flanged Outer Ring
2. VT378: Non-toxic lubricant (accidental contact with food ingredients)
3. 2RS1: Contact Seals of Nitrile Rubber (NBR) with Steel Skeleton on Both Sides
4. 2Z: Dust covers with stamped steel on both sides
2ZR: Dust caps with stamping steel on both sides and flanges on the outer ring
