Fracture causes of plastic bearing cage and factors influencing bearing performance
Plastic bearing plays an important role in social life. Bearing is made up of the cage, outer ring, rolling body and inner ring. Different bearing types, the components of the bearing are different. What are the reasons for the fracture of the imported bearing cage?
Creep is also one of the reasons for the rupture of cage. The sliding phenomenon of the so-called creep multi - finger ring is the phenomenon of the deviation of the ring relative axis or the shell to the circumference direction by sliding and moving the load point to the surrounding direction. Once the creep is produced and the matching surface is significantly worn, the worn powder may enter the inner of the bearing, forming the abnormal wear, the raceway, the frame wear and the additional load, and may cause the cage to break.
An abnormal load of the cage. If the installation is not in place, the slanting and oversize are too large, the clearance can be reduced, the friction heat, the surface softening and the abnormal exfoliation are aggravated. With the expansion of the exfoliation, the stripping of the foreign body into the holder pocket can cause the cage operation to block and produce additional load, which aggravates the wear of the cage, thus worsening. The ring action may cause the fracture of the cage.
The cage material failure and riveting defect may cause the cage fracture. Countermeasures should be taken to strictly control the manufacturing process. The invasion of foreign bodies is a common mode causing failure of cage. Due to the invasion of foreign hard foreign bodies, the wear and abnormal additional load of the cage will be increased, and the cage fracture will also occur.
Poor lubrication mainly refers to the shaft bearing transfer in the poor state, easy to form adhesive wear, make the working surface condition deteriorated, the tear produced by adhesive wear easily enter the cage, make the cage produce abnormal load, may cause the cage fracture.
Bearing plays an important role in the field of machinery. Bearing to me is that bearing can not only be applied to machinery, but also can be made into some craft toys. Bearing has a great influence on our life.
What are the factors that affect the performance of the bearing? The following analysis is carried out. The quality and basic requirements of bearing steel are closely related to the quality of steel used for bearing steel. The smelting requirement of bearing steel is much more stringent than that of general industrial steel.
The size of high accuracy requires that the steel for rolling bearings requires higher dimensional accuracy of steel because most bearing parts are subjected to pressure molding. In order to save material and improve labor productivity, most bearing rings are forged, steel ball is cold heading or hot rolling, and small size rollers are also formed by cold heading. If the precision of the steel is not high, the size and weight of the material can not be calculated accurately, but the product quality of the bearing parts can not be guaranteed, and the damage of the equipment and mould can be easily damaged.
Especially strict carbide inhomogeneity is required in bearing steel, if serious carbide distribution is not uniform, the uneven microstructure and hardness will be caused in the process of heat treatment, and the structure inhomogeneity of steel has a great influence on the contact fatigue strength. In addition, the serious carbide inhomogeneity also causes the bearing parts to produce cracks in the quenching and cooling, and the non uniformity of carbides will lead to the reduction of the life of the bearing, so in the standard of bearing materials, there is a clear special requirement for the steel of different specifications.
The strict chemical composition requires that the general bearing steel is mainly high carbon chromium bearing steel, that is, the carbon content is about 1%, the chromium is added to about 1.5%, and a small amount of manganese and silicon elements are contained in the eutectoid steel. Chromium can improve heat treatment performance, improve hardenability, microstructure uniformity, temper stability, and improve the rust resistance and grinding performance of steel. But when the chromium content exceeds 1.65%, the retained austenite in steel will be increased after quenching, which reduces the hardness and dimensional stability, increases the nonuniformity of carbides, and reduces the impact toughness and fatigue strength of the steel. For this reason, chromium content in high carbon chromium bearing steel is generally controlled below 1 or 65%. Only by controlling the chemical composition of bearing steel strictly can we get the structure and hardness that meet the bearing performance through heat treatment.
Especially strict surface defects and internal defects requirements for bearing steel, surface defects include cracks, slags, burrs, scars, oxide skins and so on. Internal defects include shrinkage, bubbles, white spots, serious porosity and segregation. These defects have great influence on bearing processing, bearing performance and service life. In the standard of bearing materials, it is stipulated that these defects are not allowed.