Deep Groove Ball Bearings
Basic Parameters
Deep groove ball bearings are a common type of rolling bearings. They consist of an outer ring, an inner ring, a set of steel balls, and a set of retainers. Deep groove ball bearings come in two types: single row and double row. The deep groove structure also includes two configurations: sealed and open. Open refers to bearings without a sealing structure. Sealed deep groove ball bearings are further categorized into dust-proof sealed and oil-proof sealed. The dust-proof sealed cover is made of steel stamping and simply prevents dust from entering the bearing raceway. The oil-proof type is a contact seal that effectively prevents the leakage of grease within the bearing.
Single-row deep groove ball bearing type is coded as 6, and double-row deep groove ball bearing is coded as 4. It features a simple structure and ease of use, making it a widely used bearing type in various production applications.
Operating Principle
Deep groove ball bearings primarily bear radial loads and can also withstand both radial and axial loads simultaneously. When they bear only radial loads, the contact angle is zero. When deep groove ball bearings have a larger radial clearance, they exhibit the performance of a " \t "_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
Deep groove ball bearings are representative rolling bearings with a wide range of applications. They are suitable for high-speed, even extremely high-speed operation, and are highly durable, requiring minimal maintenance. These bearings have a low friction coefficient, high maximum speed, simple structure, low manufacturing cost, and are easy to achieve high manufacturing accuracy. The size range and form vary greatly, 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 and also capable of handling a certain amount of axial loads.
Selecting a larger radial clearance increases the axial load capacity. When subjected to pure radial force, the contact angle is zero. With the presence of an axial force, the contact angle is greater than zero. Generally, stamped wave retainers, turned solid retainers, and sometimes nylon retainers are used.
Deep groove ball bearings, once mounted on the shaft, can limit the axial displacement of the shaft or housing in both directions within the axial clearance range of the bearing, allowing for bidirectional axial positioning. Additionally, these bearings have a certain amount of self-aligning capability; they can still operate normally when tilted 2′~10′ relative to the housing bore, although this has an impact on the bearing's lifespan. The retainers for deep groove ball bearings are typically stamped steel wave retainers, while larger bearings often use turned metal solid retainers.
Tapered roller bearings are commonly used rolling bearings. They feature a simple structure and ease of use. Primarily designed to bear radial loads, they also exhibit certain features of angular contact ball bearings when the radial clearance is increased, allowing them to withstand combined radial and axial loads. They can also bear pure axial loads when high speeds are involved and thrust ball bearings are not suitable. Compared to other types of bearings with the same specifications as the tapered roller bearings, these have a lower coefficient of friction and higher maximum speed. However, they are not shock-resistant and are not suitable for 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 with lower production costs and are 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 stop slots, deep groove ball bearings with ball recesses 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 rings on the outer ring
5. Deep groove ball bearing with ball retainer slot
6. Double-row deep groove ball bearings
According to the size of the deep groove ball bearing, they can be classified 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) Medium and Small-sized Bearings - Bearings with nominal outer diameter sizes ranging from 60 to 115mm.
(4) 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 bearing inner ring and shaft are a tight fit, and the outer ring and the bearing housing bore are a loose fit, the bearing can be pressed onto the shaft first using a press machine, then the shaft, along with the bearing, can be inserted into the bearing housing bore. During pressing, place a soft metal tube (copper or soft steel) made of a soft metal on the " _blank" bearing inner ring face. When the bearing outer ring is a tight fit with the bearing housing bore and the inner ring 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 assembly tube should be slightly smaller than the bore diameter. If both the bearing ring and the shaft as well as the bore are tight fits, both the inner and outer rings must be pressed into the shaft and bore simultaneously. The assembly tube structure should be able to simultaneously press the inner and outer ring faces 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. This is a commonly used and labor-saving method. It is suitable for the installation of bearings with large interference fit. Before heat fitting, place the bearing or the sleeve of a separable bearing into an oil tank to be uniformly heated to 80-100°C, then quickly remove it from the oil and install it onto the shaft. To prevent the inner ring end face from not fitting tightly with the shaft shoulder after cooling, the bearing can be further axially tightened after cooling. When the outer ring of the bearing is fitted tightly with a lightweight metal bearing housing, use the heat fitting method for the bearing housing to avoid scratches on the mating 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 the bearing should be hung with hooks, not placed at the bottom to prevent sediment from entering the bearing or uneven heating. There must be a thermometer in the oil tank to strictly control the oil temperature to not exceed 100°C, to prevent the tempering effect, which can reduce the hardness of the sleeve.
Tolerance
Standard deep groove ball bearings have a normal grade, all complying with GB307.1.
Gap
Standard deep groove ball bearings are available with C2, standard (CN), C3, C4, and C5 internal clearances, all conforming to GB4604.
Retaining Rack
Deep groove ball bearings typically use steel stamping retainers or brass solid retainers. When the outer diameter is less than 400 mm, steel stamping retainers are used without a suffix code. When the outer diameter is greater than 400 mm, 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-step processing: The production of general ball bearings requires 20 to 40 processes, with some exceeding 70 processes.
2. Forming Processing: The working surfaces of the bearing parts are all rotatable forming surfaces, suitable for processing by the forming method.
3. Precision Machining: The vast majority of bearing components require grinding processing for their surfaces, with the dimensions and geometrical accuracy measured in micrometers (μm).
Deep groove ball bearings, with insufficient bearing load during operation, can cause sliding between the balls and raceways, leading to wear. This tendency is especially prevalent in large deep groove ball bearings with heavy ball and retainer weights. It is anticipated that there may be instances of insufficient load during use. Please contact the relevant personnel promptly when selecting the bearings!
Causes of Rusting
In many cases, bearings may suffer from rusting, and there are numerous reasons for bearing rust. The primary factors commonly encountered in our daily lives are as follows.
1) Due to poor sealing, intrusion by moisture, dirt, etc.
2) Bearings left unused for an extended period, beyond the anti-rust period, without proper maintenance.
3) The metal surface has a high degree of roughness.
4) Exposure to corrosive chemicals, improper 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; failure of rust inhibitor or non-compliance with quality requirements.
Suffix meaning for deep groove ball
1. CN: Standard radial fit; commonly used in combination with the following letters to indicate a narrower or offset fit range
H: Narrowed gap range, equivalent to the upper half of the original gap 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: Two single row deep groove ball bearings paired back-to-back
6. DF: Two single-row deep groove ball bearings paired 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 Grade 2, operating temperature range -40 to +150°C (standard fill quantity)
11. J: Stampings Steel Retainer
12. LHT23: Lithium-based grease, NLGI Grade 2, temperature range -50 to +140°C (standard filling amount)
13. LT: Lithium-based grease, NLGI Grade 2, temperature range -55 to +110 degrees Celsius (standard fill quantity)
14. LT10: Lithium-based grease, NLGI Grade 2, temperature range -50 to +90°C (standard filling capacity)
15. M: Machined brass retaining bracket with steel ball guide. Different designs and materials are indicated by numbers added after M, such as M2
16. MA: Machined Brass Retainer, Outer Ring Guide
17. MB: Machined Brass Retaining Ring, Inner Race Guiding
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 slots and stop rings
22. N1: The outer side has grooves (for engagement with the stopper device to prevent the outer ring from rotating)
23. P5: Dimensional and rotational accuracy meets ISO tolerance grade 5
24. P6: Size and rotational accuracy conforms to ISO tolerance grade 6
25. P52：P5+C2
26. P62：P6+C2
27. P63：P6+C3
28. RS1: Contact Sealing Ring of Nitrile Butadiene Rubber (NBR) with Steel Reinforcement on One Side
29. RSH: Contact seal ring made of nitrile butadiene rubber (NBR) with steel frame 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) seal with steel reinforcing on one side
32. TH: Fiber Reinforced Phenolic Resin Retainer (Card Type)
33. TN: Injection Molding Nylon Retainer
34. TN9: Injection molded glass fiber reinforced nylon 6,6 retainers
35. VL0241: Outer surface of the outer ring with alumina coating, insulation capability up to 1000VDC
36. VL2071: Inner ring outer surface with aluminum oxide 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 pressed steel on one side
40. ZNR: Outer ring with stop slots and stop rings; the opposite side of the stop slots features a stamped steel dust cover.
41. 2RS1: Contact Seal Bushings with Steel Reinforcement on Both Sides, made of Nitrile Rubber (NBR)
42. 2RSH: Contact seal rings with steel reinforced NBR (Nitrile Butadiene Rubber) on both sides
43. 2RSL: Low-friction NBR (Nitrile Butadiene Rubber) sealing rings with steel reinforcement on both sides
44. 2RZ: NBR (Nitrile Butadiene Rubber) low friction seal circlips with steel frames on both sides
45. 2Z: Dust caps with stamped steel on both sides
46. 2ZNR: Outer ring with stop slots and stop rings, with stamped steel dust caps on both sides
Common suffix for ball gap with casing:
1. C3: Radial Clearance Larger Than Standard Group
2. N: Outer ring with stop slot
3. NR: Outer ring with stop groove and stop ring
4. Z: Dust cover with stamped steel on one side
5. ZNR: Outer ring with stop slots and stop rings, the other side of the stop slots features a stamped steel dust cover
6. 2Z: Dust caps with stamped steel on both sides
7. 2ZNR: Outer ring with stop slot and stop ring, with stamped steel dust caps on both sides
The meaning of suffixes for stainless steel:
1. R: Outer ring with flange
2. VT378: Non-toxic lubricant (accidental contact with food ingredients)
3. 2RS1: Contact seal rings of nitrile rubber (NBR) with steel inserts on both sides
4. 2Z: Pressed steel dust covers on both sides
5. 2ZR: Dust covers with stamped steel on both sides and a flanged outer ring
