Deep groove ball bearing:
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 ball structure also includes two structures: sealed and open. Open refers to bearings without a sealing structure. Sealed deep groove ball bearings are further divided into dust-proof sealed and oil-proof sealed types. The dust-proof sealed cover is made of steel plate stamping and simply prevents dust from entering the bearing raceway. The oil-proof type is a contact seal, which effectively prevents the grease within the bearing from leaking out.
Single-row deep groove ball bearing type code is 6, double-row deep groove ball bearing code is 4. Its structure is simple, easy to use, and it is a type of bearing that is widely used in production and application.
Working Principle
Deep groove ball bearings primarily bear radial loads and can also simultaneously bear radial and axial loads. 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 " _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 and even super-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 precision. The size range and form vary greatly, and they are used in precision instruments, low-noise motors, automobiles, motorcycles, and general machinery industries, making them one of the most widely used types of bearings in the mechanical industry. They primarily bear radial loads but can also handle 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 retainer, turned solid retainer, or sometimes nylon retainers are used.
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, allowing for bidirectional axial positioning. Additionally, these bearings possess a certain degree of self-aligning ability; they can still operate normally when tilted 2′~10′ relative to the housing bore, although this may affect the bearing's service life. The retainers for deep groove ball bearings are typically stamped steel wave retainers, while larger bearings often use turned metal solid retainers.
Deep groove ball 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 angular contact ball bearing characteristics when the radial clearance is increased, allowing them to withstand combined radial and axial loads. They can also bear pure axial loads when high rotational speeds are involved and thrust ball bearings are not suitable. Compared to other types of bearings with the same specification and size as the deep groove ball bearings, these have a lower friction coefficient and a higher maximum speed. However, they are not shock-resistant and are not suitable for bearing heavy loads.
Bearings construction
Deep groove ball bearings have a simple structure, making it easier to achieve high manufacturing precision compared to other types. This facilitates mass production in series at a lower cost, and they are extremely common in use. 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 grooves 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 bearings with dust cover
3. Single-row deep groove ball bearings with dust caps and seals
4. Single-row deep groove ball bearing with stop slots and a stop ring on the outer ring
5. Deep groove ball bearings with ball seat grooves
6. Double-row deep groove ball bearing
According to the size and dimensions, deep groove ball bearings can be categorized as:
(1) Miniature Bearings - Bearings with nominal outer diameter dimensions 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 a nominal outer diameter size of 440mm or larger.
Deep groove ball bearings are used in gearboxes, instruments and meters, motors, household appliances, internal combustion engines, transportation 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 race 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 pressing, place a soft metal tube (copper or soft steel) made of soft metal on the " _blank" bearing inner race end face. When the bearing 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 assembly tube should be slightly smaller than the bore diameter. If both the bearing rings and the shaft and housing bore are tight fits, the inner and outer races must be pressed into the shaft and bore simultaneously. The structure of the assembly tube should be able to simultaneously press the end faces of both the bearing inner and outer races.
Deep Groove Ball Bearing Installation Method Two: Heat Fit: An installation method that uses heat to expand the bearing or housing to transition from a tight fit to a loose fit. This is a commonly used and labor-saving method. It is suitable for installing bearings with large interference fits. Before heat fitting, place the bearing or separable bearing ring in an oil tank and uniformly heat it to 80-100°C, then 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 axially tightened after cooling. When the outer race of the bearing is fitted tightly with a lightweight metal bearing housing, use the heat fitting method for the bearing housing to avoid scratching the mating surface. When heating the bearing in an oil tank, there should be a grid at a certain distance from the bottom of the tank, or use hooks to hang the bearing, ensuring it does not touch 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 no more than 100°C to prevent tempering effects that could reduce the hardness of the ring.
Tolerance
Standard deep groove ball bearings are of ordinary grade and fully comply with GB307.1.
Gap
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 typically use 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: The production of general bearings usually requires 20 to 40 processes, with some exceeding 70.
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 majority of bearing components require grinding processing for their surfaces, with both the grinding dimensions and geometric 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 abrasion. This tendency is especially prevalent in large deep groove ball bearings with heavy ball and retainer weights. It is anticipated that there may be insufficient load conditions during use. Please contact the relevant personnel promptly when selecting the bearings!
Causes of Rust Formation
In many cases, bearings may suffer from rusting, and there are numerous reasons for this. The main factors we commonly encounter in our daily lives include the following.
1) Due to poor sealing, invasion by moisture, dirt, etc.
2) Bearings left unused for an extended period, exceeding the anti-rust duration, lack of maintenance and care.
3) The surface roughness of the metal is quite large.
4) Exposure to corrosive chemicals, insufficient cleaning of bearings, surface contamination, or contact with the bearings by sweaty hands; failure to package or install the bearings promptly after cleaning, leading to long-term exposure to air and moisture, which can lead to corrosion and contamination.
5) Environmental temperature and humidity, as well as contact with various environmental media; rust inhibitor failure or non-compliance with quality requirements.
Suffix meaning for deep groove ball
1. CN: Standard radial clearance; usually used in combination with the following letters to indicate a narrower or offset clearance 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
P: Offset gap range, consisting of the upper part of the original gap range and the lower part 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 greater than C4
5. DB: A pair of single row deep groove ball bearings matched in back-to-back configuration
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 2 consistency, temperature range -30 to +150 degrees Celsius (standard filling quantity)
10. GXN: Polyurea grease, NLGI 2 consistency, temperature range -40 to +150°C (standard filling amount)
11. J: Stamped 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 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, steel ball guide. Different designs and materials are indicated by numbers following the M, such as M2
16. MA: Machined Brass Retaining Ring, Outer Ring Guide
17. MB: Machined Brass Retainer, Inner Ring Guide
18. MT33: Lithium-based Grease, NLGI Grade 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 ring
22. N1: The outer side has grooves (used to配合 with a stopper device to prevent the outer ring from rotating)
23. P5: Dimensional accuracy and rotational accuracy meet ISO tolerance grade 5
24. P6: Dimensional 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 made of NBR (Nitrile Butadiene Rubber) with steel reinforcing 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) sealing ring with a steel skeleton on one side
32. TH: Fiber Reinforced Phenolic Resin Retaining Rack (Card Type)
33. TN: Injection Molding Nylon Retainer
34. TN9: Injection molded glass fiber reinforced nylon 6,6 retainer
35. VL0241: Outer ring with an aluminum oxide coating, insulating capability up to 1000VDC
36. VL2071: Inner surface with alumina coating, insulation capability up to 1000VDC
37. WT: Polyurea grease, NLGI 2 consistency, temperature range -40 to +160°C (standard fill quantity)
38. Y: Stamped copper retaining bracket
39. Z: Dust cover with stamped steel on one side
40. ZNR: Outer ring with stop slots and stop rings; the other side of the stop slots features a stamped steel dust cover.
41. 2RS1: Contact Sealing Washers with Steel Retainer on Both Sides, made of Nitrile Rubber (NBR)
42. 2RSH: Contact seal rings made of nitrile rubber (NBR) with steel reinforcing on both sides
43. 2RSL: Low-friction NBR (Nitrile Butadiene Rubber) sealing washers with steel reinforcing on both sides
44. 2RZ: Low-friction NBR (Nitrile Butadiene Rubber) sealing rings with steel reinforcement 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 suffix for fitted ball gap:
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 slots and stop rings; the other side of the stop slots features a stamped steel dust cover.
6. 2Z: Dust covers 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:
R: Outer ring with flange
2. VT378: Non-toxic lubricant (for 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
5. 2ZR: Dust caps with stamping steel on both sides and flanged outer ring
