Technical standards and precautions for rolling bearings

Writer： admin Time：2022-06-28

Technical standards and precautions for rolling bearings

       1. The base shaft is used for the cooperation between the bearing and the shaft, and the base shaft is used for the cooperation between the non-standard bearing and the housing. The values of bearing dimensional tolerance and rotation accuracy are in accordance with GB307-84.

　　 2. The journal and the inner hole of the bearing box matched with the bearing are in accordance with GB1031-83. The roughness Ra value of the journal is less than 1.6μm, and the roughness Ra value of the inner hole of the bearing box is less than 2.5μm.

　　3. When bearing rings and rollers are made of GCr15 and ZGCr15 steel, the hardness values of the rings and rollers should be 61~65HRC; when they are made of GCr15SiMn and ZGCr15SiMn steels, their hardness values should be 60~64HRC. The hardness inspection method and the uniformity of the hardness of the same parts are in accordance with JB1255.

　　 4. Check the radial clearance and axial clearance of the bearing should comply with the provisions of GB4604-84.

　　 5. The inner and outer ring raceways of the rolling bearing should be free from flaking and severe wear, and there should be no cracks on the inner and outer rings; the balls should be free from wear, the cage should not be severely deformed, and there should be no abnormal noise and vibration during rotation, and should be gradually stopped when stopped.

     6. For C-class tolerance tapered roller bearings, the contact accuracy of the roller and the raceway of the ring is color-checked under the action of a certain load. The contact trace should be continuous, and the contact length should not be less than 80 of the roller bus.

　　The life of the bearing is closely related to manufacturing, assembly, and use. It must be done in every link to make the bearing in the best running state, thereby extending the service life of the bearing.

    1. The selection and control of the tolerance of the shaft and the bearing room: the bearing should rotate flexibly without being blocked after being pressed into the bearing. If the rotation is obviously inflexible, it means that the size of the shaft is too large, and the tolerance should be adjusted downward. If the bearing rotates by hand after pressing into the shaft, there will be a sense of rustle, it may be that the tolerance of the shaft is too large or the roundness of the shaft is not good. Therefore, when controlling the tolerance of the shaft and the bearing room, the roundness must be well controlled. At present, many domestic manufacturers only control the tolerance, and do not control the roundness.

　　 2. Bearing assembling method: because the bearing is a high-precision product, it is easy to damage the bearing channel if it is improperly assembled, resulting in bearing damage. When assembling the bearing, there should be a special mold, which can not be knocked at will. When pressing into the shaft, only a small ring can be used to force, when pressing a large ring, only a large ring can be used. Air pressure or hydraulic pressure is required during assembly, and the upper and lower molds should be outside the horizontal state during press-fitting. If inclined, the bearing channel will be damaged due to the force, and the bearing will be induced.

　　 3. Prevention of assembly of foreign objects: When the bearing is mounted on the rotor for dynamic balancing, it is easy to get iron chips generated during dynamic balancing into the bearing, so it is best to do dynamic balancing before installing the bearing. For ease of assembly, some manufacturers apply some oil or grease to the bearing room during assembly to lubricate the effect. However, it is often difficult for the operator to control the quantity. If oil or grease accumulates in the bearing room, it will be very difficult when the bearing rotates. Easy to enter the inside of the bearing along the shaft. It is best not to apply oil or grease to the bearing room. If it is not necessary, it must be controlled not to accumulate in the bearing room.