1: bearing cutting
When the grindstone surface contacts with the convex peak of the rough raceway surface, the contact area is small and the force per unit area is large. Under certain pressure, the grindstone is firstly subjected to the "reverse cutting" action of the bearing workpiece, so that part of the grindstone surface falls off and breaks, revealing some new sharp grindstone and edge.At the same time, the surface bump of bearing workpiece is subjected to rapid cutting, and the bump and grinding metamorphism layer on the surface of bearing workpiece are removed by the action of cutting and reverse cutting.This stage is called the cutting stage, in which most of the metal residue is removed.
2: half cutting of bearing
As the processing continues, the surface of the bearing workpiece is gradually worn down.At this time, the surface contact area between the grinding stone and the workpiece increases, the pressure per unit area decreases, the cutting depth decreases, and the cutting ability decreases.At the same time, the pores on the surface of the grindstone are blocked, and the grindstone is in the state of semi-cutting.This stage is called the half cutting stage of bearing finishing. In the half cutting stage, the cutting marks on the bearing workpiece surface become lighter and a darker luster appears.
3: optical whole stage
This is the last step in the superfinishing of the bearing.As the surface of the workpiece is gradually polished, the contact area between the grindstone and the surface of the workpiece is further increased, and the surface of the grindstone and the bearing workpiece is gradually isolated by the lubricating oil film, the pressure on the unit area is very small, the cutting effect is reduced, and the cutting is automatically stopped.This phase is called the optical integration phase.There is no cutting mark on the surface of the workpiece in the finishing stage.
The function of bearing fit is to make the stationary ring and the rotating ring of the bearing consolidate with the stationary part (usually the bearing housing) and the rotating part (usually the shaft) of the mounting part respectively, so as to realize the basic task of transferring load in the rotating state and defining the position of the moving system relative to the stationary system.
In the shaft and bearing housing, the bearing is required to be fixed in radial, axial and tangential directions.The radial and tangential orientation is realized by the tight fit of bearing ring.Generally, axial limit parts such as end caps and retaining rings are used to limit the axial position within the clearance range.
Performance of preventing adhesion and forming boundary lubrication in direct contact between bearing shaft diameter and bearing bush.The material factors affecting the friction compatibility of the friction pair are:
(1) the degree of difficulty in forming the alloy on the metallurgy of the auxiliary materials.
(2) affinity between materials and lubricants.
(3) friction factor of the auxiliary material in the state of no lubrication.
(4) microstructure of materials.
(5) thermal conductivity of materials.
(6) the size of the material's surface energy and the characteristics of the oxide film.
The high-pressure oil is injected into the bearing through the nozzle with an oil pump, and the oil injected into the bearing flows into the oil groove through the other end of the bearing.When the bearing rotates at a high speed, the rolling body and the cage also make the surrounding air form airflow at a fairly high rotation speed. It is difficult to send the lubricating oil to the bearing by the general lubrication method. At this time, the lubricating oil must be sprayed into the bearing by means of high-pressure injection, and the position of the nozzle should be placed between the inner ring and the center of the cage.