When selecting the type of bearing with, you should consider the size of the load, the direction together nature, the level of speed, rotation accuracy level and disassembly convenience and other factors. General selection principles are as follows:
1, when the load direction change, the rotation of the ferrule should bear than fixed with some rings.
2, the load, the higher the speed, and vibration and shock, should cooperate more tightly.
3, when the rotation precision bearings are higher, we should adopt a tight fit, with the aid of interference to reduce the original bearing clearance, improve the rotary precision bearing.
4, when the axial bearing to be considered when swimming, with the outer ring and the housing bore should be looser.
5, with the bearing and the hollow shaft should be tight to prevent the shaft due to shrinkage leaving loose fit.
Axial thermal expansion gap: △ Ⅰ = a (to-t1) I
Length between two bearings is 800MM, when the operating temperature is 50 ℃, the ambient temperature during assembly of 5 ℃, seeking elongation axis thermal expansion? (Steel linear expansion coefficient: a = 11 * 0.000001MM / degree .MM)
△ Ⅰ = a (to-t1) Ⅰ = 11 * 0.000001MM / degree .MM * (50-5) * 800 = 0.396 (MM)
One end of the bearing assembly should be left axial thermal expansion gap C, and should be greater than 0.396MM (not consider the body of thermal expansion)
Rolling is the main component of the supporting shaft and rotating parts, it is compared with the sliding bearings have to start small resistance, high precision turning, small temperature rise, long life, compact structure, fast speed, easy assembly and disassembly, and a high degree of interchangeability, etc. Features.
Rolling preload
When the Rolling adjust to not only eliminate the gap completely, but a certain amount of interference, this method is called preload.
Reasonable preload, the rolling body and the inner and outer rings of the bearing raceway contact occurs at certain elastic deformation of the contact area between them increases, the respective rolling elements also increasingly uniform force, thereby increasing bearing stiffness and improve swing accuracy and vibration resistance. However, if more than a reasonable amount of preload, not only the above-mentioned effect is not obvious, but will make increased wear and increased bearing heat, shortened life expectancy, carrying capacity and limit bearing speed is reduced, when installed by bearing, must be based on the work of bearing case, select a reasonable amount of preload.
