1. Features of FAG bearing steel:
The steel is self-produced, with high cleanliness and appropriate mass fraction of each element (according to the test data of NSK company, when the oxygen content in the bearing steel is 30×106, 15×106, 10×106 and 5×106, the ratio of the life of the bearing is 1 :4:14:30). Under the conditions of correct bearing installation, small load and good lubrication, some FAG bearings can reach infinite life.
2. Select materials according to working conditions
(1) Ordinary small size: use high-carbon chromium bearing steel (Chinese steel number GCr15, German steel number DIN100Cr6). This kind of steel has the advantages of high surface hardness (Rockwell hardness value is HRC58~HRC65), wear resistance and cheap price.
(2) Large size and heavy load: Carburized bearing steel is used. The surface hardness of this steel is similar to that of high-carbon chromium bearing steel, but the core has lower hardness and higher toughness. When the bearing bears heavy load or impact load, the high surface hardness can meet the wear resistance requirements, and the high toughness of the core can act as a buffer role, so as not to make the bearing crushed by the impact load.
(3) High-temperature bearings: For bearings other than engineering plastic cages, the maximum operating temperature can reach 150°C, and the higher operating temperature is indicated by the suffix, respectively S1–200°C, S2–250°C, S3–300 ℃, S4–350℃.
(4) Others: stainless steel bearings (such as S60xx.W203B); main shaft bearings (angular contact ball bearings) are made of ceramic materials, such as HCB70xx, HCS70xx, which have high temperature resistance, low temperature resistance, wear resistance, corrosion resistance, light weight, and high-speed centrifugal force Small, insulation and other advantages.
2. Precision and Tolerance
1. High precision in size and rotation:
In addition to meeting international precision grade standards, FAG bearings also have their own corporate precision standards. Such as the suffix: P4S means that the dimensional tolerance is the same as that of ordinary P4, but the rotation accuracy of the bearing is ordinary P2. In addition, there are bearings with higher precision classes, such as bearings with the suffixes SP (super high precision) and UP (extra high precision).
2. Small size tolerance zone:
FAG bearings have smaller dimensional tolerances, smooth operation and longer life. In a batch of bearings of the same type, the size dispersion is small (the proportion of extreme size bearings is small, and the assembly and use are more reliable), which conforms to the normal distribution.
3. Processing technology:
1. Heat treatment: The heating temperature of FAG bearing heat treatment is less than 150 ℃, and the metallographic structure inside the metal is stable, so that the dimensional fluctuation of the finished product is small and the precision is higher.
2. Cold rolling process: During the production and processing of bearings, the shape and size of the bearings are rolled out using precision equipment at room temperature. Turning processing is omitted in the production process, and the internal streamlines of the metal are completely preserved, and the service life can be greatly improved. improve.
3. Wire drawing process: when the bearing components are produced and processed, the last process is super-finishing. At this time, there are cross-reticular patterns on the surface. A few large enterprises add wire drawing process after this process. The purpose is to make the pattern change along the rolling body. The direction of rolling is to reduce friction and noise. After this process, the working surface of the bearing has compressive stress, which can improve the fatigue life of the bearing.
4. Model exchange and size calculation
1. Angular contact ball bearings:
7xxxB: Contact angle 40°.
B7xxx.C: contact angle 15° (high-speed spindle bearings)
B7xxx.E: contact angle 25° (high-speed spindle bearings)
Dual row 32xxB and 33xxB == 52xx and 53xx (NACHI) with ball notch, which has a contact angle of 35°. Double row FAG angular roller ball bearings 32xx and 33xx without suffix are indicated in the same way as other brands. Among them, 33xxDA means that the bearing is a double-half inner ring, and the contact angle is 45°
Combination mode: O type=DB, X type=DF, T type=DT.
2. FAG angular contact ball bearings:
This type of bearing mainly bears axial load, single row only bears one-way axial load, and double row can bear two-way axial load. Its model series are:
Single row: 7602xxx, 7603xxx series
Double row: 2344xx, 2347xx series
3. Cylindrical roller bearings for pulleys:
Normal: NNF50xx.B.2LS.V (FAG) == NAS50xxUUNR (IKO) E50xx (NACHI)
Full complement type: NNC49xxV (FAG) == NAG49xx (IKO)
4. Self-aligning ball bearings:
Bearing model series are 112xx, 113xx and 115xx. The inner ring of this type of bearing is lengthened and has a card slot for the set screw to fix the shaft. If the bearings are installed in pairs, their card slots should be opposite to prevent the movement of the two axial directions.
Where: 112xx == 12xx, 113xx == 13xx
5. KH series of outer spherical bearings with eccentric sleeve:
Metric: 162xx == KH2xx(ASAHI). The inner diameter size is the same as the ordinary calculation method.
Among them: 16203/12 == KH201; 16203/15 == KH202; 16203/17 == KH203.
Such as 16207.104, its inner diameter size is: 1+4/16 inches, that is 31.75mm;
Features of FAG bearings