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 types: sealed and open. Open refers to bearings without a sealing structure. Sealed deep groove ball bearings are further divided into dustproof sealed and oil-resistant sealed types. The dustproof sealed cover is made of steel plate stamping and only serves to simply prevent dust from entering the bearing raceway. The oil-resistant type is a contact oil seal, which effectively prevents the grease within the bearing from spilling out.
Single-row deep groove ball bearing type is coded as 6, while 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 " _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.
Bearings Characteristics
Deep groove ball bearings are representative rolling bearings with wide applications. They are suitable for high-speed operations, even at extreme speeds, 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 are diverse, 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 withstand 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, a stamped wave retainer is used, as well as a turned solid retainer, and sometimes a nylon frame is also employed.
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, thus enabling bidirectional axial positioning. Additionally, these bearings possess a certain degree of self-aligning capability; they can still operate normally when inclined 2′ to 10′ relative to the housing bore, although this may affect the bearing's service life. The retainers for deep groove ball bearings are typically made of steel plate stamped into wavy 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 are easy to use. Primarily designed to bear radial loads, they also exhibit certain features of angular contact ball bearings when the radial clearance of the bearing is increased, enabling them to withstand combined radial and axial loads. They can also bear pure axial loads when high-speed operation is required and thrust ball bearings are not suitable. Compared to other types of bearings with the same specifications as deep groove ball bearings, these have a lower friction coefficient and higher maximum speed. However, they are not shock-resistant and are not suitable for bearing heavy loads.
Bearing structure
The deep groove ball bearing has a simple structure, making it easier to achieve high manufacturing precision compared to other types. This facilitates mass production in series and results in lower production costs, making it extremely widespread. In addition to the basic type, there are various modified structures, such as deep groove ball bearings with dust covers, those with rubber sealing rings, ones with locking grooves, high-load capacity deep groove ball bearings with ball insertion notches, 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 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.
Medium to Large Size 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 more.
Deep groove ball bearings are suitable for applications such as 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 fits tightly with the shaft and the outer race fits relatively loosely with the bearing housing bore, the bearing can be first pressed onto the shaft using a press machine. Then, insert the shaft with the bearing into the bearing housing bore. During the press fit, place a soft metal tube (copper or soft steel) made of soft metal on the end face of the bearing inner race. When the bearing outer race fits tightly with the bearing housing bore and the inner race fits relatively loosely with the shaft, the bearing can be pressed into the bearing housing bore first. In this case, the outer diameter of the fitting tube should be slightly smaller than the bore diameter. If both the bearing races and the shaft and housing bore are tightly fitted, both the inner and outer races should be pressed into the shaft and bore simultaneously. The fitting tube structure 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 Installation: This method involves heating the bearing or bearing housing to utilize thermal expansion, converting a tight fit into a loose fit for installation. It is a commonly used and labor-saving installation method. Suitable for bearings with significant interference fit, this method requires placing the bearing or separable bearing ring in an oil bath and heating it uniformly to 80-100°C before removing it and quickly mounting it onto the shaft. To prevent the inner ring face from not fitting tightly against the shaft shoulder upon 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, the heat fit installation method for the bearing housing can be used to avoid scratching the mating surfaces. When heating the bearing in an oil bath, there should be a grill at a certain distance from the bottom of the tank, or the bearing should be hung with hooks to prevent it from resting on the bottom, which could allow impurities to enter the bearing or uneven heating. A thermometer must be present in the oil bath to strictly control the oil temperature to no more than 100°C to prevent tempering effects that could reduce the hardness of the rings.
Tolerance
Standard deep groove ball bearings are of ordinary grade and fully comply with GB307.1.
Clearance space
Standard deep groove ball bearings feature internal clearances of C2, standard (CN), C3, C4, and C5 levels, all in compliance with GB4604.
Retaining Rack
Deep groove ball bearings generally 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: General bearing production requires 20 to 40 processes, with some exceeding 70.
2. Forming Processing: The working surfaces of the bearing parts are all rotational forming surfaces, suitable for processing by forming methods.
3. Precision Machining: The majority of bearing components require grinding for surface finishing, with the size 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 is particularly prone in large deep groove ball bearings with heavy ball and retainers. It is anticipated that insufficient load may occur during use, so please contact the relevant personnel promptly when selecting bearings!
Causes of Rusting
In many cases, bearings can experience rusting, and there are numerous reasons for this. The most common factors we encounter in everyday life include:
1) Due to poor sealing, water, dirt, and other contaminants have infiltrated.
2) Bearings left unused for an extended period, beyond the anti-rust duration, lack maintenance and care.
3) The metal surface has a high degree of roughness.
4) Exposure to corrosive chemicals, improper 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 cause contamination and damage.
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, equivalent to the upper half of the original gap range and the lower half of the next gap range. The above letters are applicable 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: Single-row deep groove ball bearings paired in back-to-back arrangement
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. Enhanced design
9. GJN: Polyurea grease, NLGI Grade 2, temperature range -30 to +150 degrees Celsius (standard filling amount)
10. GXN: Polyurea grease, NLGI 2 consistency, temperature range -40 to +150°C (standard fill quantity)
11. J: Stampings Steel Retainer Bracket
12. LHT23: Lithium-based Grease, NLGI 2 Consistency, Temperature Range -50 to +140°C (Standard Fill Quantity)
13. LT: Lithium-based grease, NLGI Grade 2, temperature range -55 to +110 degrees Celsius (standard fill quantity)
14. LT10: Lithium-based grease, NLGI 2 consistency, 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 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 has grooves (used to accommodate the stopper device to prevent the outer ring from rotating)
23. P5: Dimensional and rotational accuracy meets 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 Skeleton on One Side
29. RSH: Contact Seals of Nitrile Butadiene Rubber (NBR) with Steel Reinforcement on One Side
30. RSL: Low-friction NBR (Nitrile Butadiene Rubber) seals with steel reinforcement on one side
31. RZ: Low-friction NBR (Nitrile Butadiene Rubber) seals with steel reinforcing on one side
32. TH: Fiber-reinforced phenolic resin shelf (card type)
33. TN: Injection Molding Nylon Retainer
34. TN9: Injection Molding 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 2 consistency, 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 slot and stop ring, with a stamped steel dust cover on the opposite side of the stop slot
41. 2RS1: Contact Seal Ring with Steel Reinforcement on Both Sides, Nitrile Rubber (NBR)
42. 2RSH: Contact Sealing Washers with Steel Reinforcement on Both Sides, made of Nitrile Rubber (NBR)
43. 2RSL: Low-friction sealing washers made of nitrile rubber (NBR) with steel frame on both sides
44. 2RZ: Low-friction NBR (Nitrile Butadiene Rubber) sealing rings with steel frame 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 covers on both sides
Common suffix for assembled ball gaps:
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 featuring a stamped steel dust cover
6. 2Z: Pressed steel dust caps on both sides
7. 2ZNR: Outer ring with stop slot and stop ring, with stamped steel dust caps on both sides
The meaning of stainless steel suffix:
1. R: Flanged Outer Ring
2. VT378: Non-toxic Lubricant (Accidental Contact with Food Ingredients)
3. 2RS1: Contact seal rings made of nitrile rubber (NBR) with steel reinforcing 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
