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 structure of deep groove ball bearings is also available in sealed and open versions. Open refers to bearings without a sealing structure. Sealed deep groove ball bearings are further divided into dustproof sealed and oilproof sealed types. The dustproof sealed cover is made of steel plate stamping and simply prevents dust from entering the bearing raceway. The oilproof type is a contact seal that effectively prevents the lubricant from leaking out of the bearing.
Single-row deep groove ball bearing type code is 6, double-row deep groove ball bearing code is 4. It features a simple structure and ease of use, making it a commonly produced and widely applied type of bearing.
Working Principle
Deep groove ball bearings primarily support radial loads and can also bear 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 "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 wide applications. They are suitable for high-speed and even super-speed operations 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. They are one of the most widely used types of bearings in the mechanical industry, primarily bearing radial loads but also capable of supporting a certain amount of axial loads.
Selecting a larger radial clearance increases the axial load-bearing capacity. When subjected to pure radial force, the contact angle is zero. In the presence of an axial force, the contact angle is greater than zero. Generally, a stamping wave-shaped retainer is used, as well as a turned solid retainer, and sometimes a nylon frame.
Deep groove ball bearings, once mounted on the shaft, can limit the axial displacement of the shaft or housing in both directions within the bearing's axial clearance range, thus allowing for bidirectional axial positioning. Additionally, these bearings possess a certain degree of self-aligning capability; they can still operate normally when inclined by 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 wave retainers, while larger bearings often use turned metal solid retainers.
Deep groove ball bearings are commonly used rolling bearings. They have a simple structure and are easy to use. Mainly used to bear radial loads, but when the radial clearance of the bearing is increased, they exhibit certain performance characteristics of angular contact ball bearings, capable of bearing 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 specification and size as the deep groove ball bearing, these bearings 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, which makes them easy to achieve high manufacturing precision compared to other types. This facilitates serial mass production and keeps production costs low, 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 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 nominal outer diameter sizes of 26mm or less.
(2) Small Bearings - Bearings with nominal outer diameter sizes ranging from 28 to 55mm.
(3) Medium to Small Bearings - Bearings with nominal outer diameter sizes ranging from 60 to 115mm.
(4) Medium to Large Size Bearings —— Bearings with nominal outer diameter sizes ranging from 120 to 190mm
Large Bearings - Bearings with nominal outer diameter sizes ranging from 200 to 430mm.
(6) Extra-large Bearings -- Bearings with nominal outer diameter sizes exceeding 440mm.
Deep groove ball bearings are used in gearboxes, instruments and meters, motors, household appliances, internal combustion engines, vehicles, agricultural machinery, construction equipment, construction machinery, roller skate wheels, yo-yos, and more.
Installation Method
Deep Groove Ball Bearing Installation Method 1: 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 first pressed onto the shaft using a press. Then, the shaft with the bearing can be inserted into the bearing housing bore. During the pressing, a soft metal tube (copper or soft steel) made of a soft metal should be placed on the end face of the _blank inner race of the 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 housing bore first. In this case, the outer diameter of the assembly tube should be slightly smaller than the diameter of the housing bore. If both the bearing rings and the shaft and housing bore are tight fits, both the inner and outer races need to be pressed into the shaft and bore simultaneously. The assembly tube structure 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 uses heat to expand the bearing or bearing housing, converting a tight fit into a loose fit. This is a commonly used and labor-saving method. It is suitable for installing bearings with a large interference fit. Before heat fitting, place the bearing or the sleeve of a separable bearing in an oil tank and heat it uniformly to 80-100°C. Then, remove it from the oil and quickly install it onto the shaft. To prevent the inner ring face and the shaft shoulder from not fitting tightly after cooling, re-tighten the bearing axially 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 surfaces. When heating the bearing in an oil tank, there should be a grill at a certain distance from the bottom of the tank, or hang the bearing with hooks; the bearing should not be placed at the bottom of the tank to prevent impurities 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 may reduce the hardness of the sleeve.
Tolerance
Standard deep groove ball bearings are of general grade, all complying with GB307.1.
Clearance
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, while 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 typically requires 20 to 40 processes, with some exceeding 70.
2. Forming Processing: The working surfaces of bearing parts are rotational forming surfaces, suitable for processing by the forming method.
3. Precision Machining: The majority of bearing parts require grinding for surface finishing, with the 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. Particularly, large deep groove ball bearings with heavy ball and retainers are prone to this issue. It is anticipated that there may be cases of insufficient load during use. Please promptly contact the relevant personnel when selecting bearings!
Causes of Rust Formation
In many cases, bearings can suffer from rusting, and there are various reasons for this. 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 left unused for an extended period, beyond the anti-rust duration, lack proper maintenance.
3) The surface roughness of the metal is quite large.
4) Exposure to corrosive chemicals, improper cleaning of bearings, surface contamination, or contact with sweat-soaked hands, failure to package or install the bearings promptly after cleaning, and long-term exposure to air, leading to moisture intrusion 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
Offset clearance range, equivalent to the upper half of the original clearance range and the lower half of the next group of clearance ranges. The above letters also apply to the following clearance group combinations for 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 Larger than C3
4. C5: Radial Clearance greater 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 2 consistency, temperature range -30 to +150 degrees Celsius (standard filling quantity)
10. GXN: Polyurea grease, NLGI grade 2, temperature range -40 to +150°C (standard fill quantity)
11. J: Stampings Steel Retainer 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 degrees Celsius (standard fill capacity)
15. M: Machined brass retainer, steel ball guide. Different designs and materials are identified by numbers following the letter 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 Grade 3, temperature range -30 to +120 degrees Celsius (standard filling amount)
20. N: Outer ring with stop slot
21. NR: Outer ring with stop slot and stop ring
22. N1: The outer ring side features grooves (used to accommodate the stop 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 Seal Ring of Nitrile Butadiene Rubber (NBR) with Steel Reinforcement on One Side
29. RSH: Contact Seal Ring of Nitrile Butadiene Rubber (NBR) with Steel Reinforcement on One Side
30. RSL: Low-friction NBR (Nitrile Butadiene Rubber) sealing ring with steel reinforcing on one side
31. RZ: Low-friction NBR (Nitrile Butadiene Rubber) sealing rings 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 retainer
35. VL0241: Outer surface of the outer ring coated with alumina, insulating capability up to 1000VDC
36. VL2071: Inner ring outer surface with aluminum oxide coating, insulation capability up to 1000VDC
37. WT: Polyurea grease, NLGI 2 consistency, temperature range -40 to +160 degrees Celsius (standard filling quantity)
38. Y: Stamped copper retaining bracket
39. Z: Dust cover with stamped steel on one side
40. ZNR: Outer ring with stop slot and stop ring, the other side of the stop slot equipped with a stamped steel dust cover
41. 2RS1: Contact seal ring with steel reinforced Nitrile Butadiene Rubber (NBR) on both sides
42. 2RSH: Contact seal retainers with steel reinforcement on both sides made of nitrile rubber (NBR)
43. 2RSL: NBR low-friction sealing rings with steel skeleton on both sides
44. 2RZ: Low-friction NBR (Nitrile Butadiene Rubber) sealing rings with steel frame on both sides
45. 2Z: Dust caps with pressed steel on both sides
46. 2ZNR: Outer ring with stop slots and stop rings, with stamped steel dust caps on both sides
Common suffixes for ball gap with packaging:
1. C3: Radial Clearance Greater 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 caps with stamped steel on both sides
7. 2ZNR: Outer ring with stop slots and stop rings, with stamped steel dust caps 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 made of NBR (Nitrile Rubber) with steel reinforcement on both sides
4. 2Z: Dust covers with stamped steel on both sides
5. 2ZR: Dust covers with stamped steel on both sides and a flanged outer ring
