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The bearing lubricated with grease and oil drops is difficult to produce a complete bearing oil film between relative moving surfaces due to Non Liquid Sliding insufficient oil. The bearing can only work under mixed friction and belongs to non-liquid sliding bearing.
The main failure forms of this kind of bearing are wear and gluing, followed by surface crushing and pitting. Therefore, the calculation criterion of the bearing is to maintain the bearing material and boundary oil film, and control the average pressure P, sliding speed V and product PV of the bearing not to exceed the allowable values respectively, that is:
p≤[p]； v≤[v]； pv≤[pv]
Where: [P], [v] and [PV] are the allowable values
For radial bearings: P = f / (BD); v=πdn
For thrust bearings:
p=F/{(π/4)(d2-d02) ξ}； v=π{(d+d0)/2}n
Where: D and d0 – outer diameter and inner diameter of circular contact Non Liquid Sliding surface, usually d0 = (0.6 ~ 0.8) d; ξ- Considering the coefficient of reducing the contact area due to the opening of oil trench, usually ξ= 0.8～0.9。
However, under some special operating conditions, the thrust ball Non Liquid Sliding bearing can obtain a longer life than the traditional calculation, especially under light load.
These special operating conditions are the surface damage that may be caused when the rolling surface (track and rolling parts) is effectively Non Liquid Sliding separated and limited by a lubricating oil film. In fact, under ideal conditions, the so-called permanent bearing life is possible.
The service life of ina bearing is in revolutions (or hours of operation at a certain speed). Definition: the bearing within this service life shall have Non Liquid Sliding preliminary fatigue damage (peeling or defect) on any bearing ring or rolling element.
However, no matter in laboratory test or in actual use, it can be clearly seen that the actual life of thrust ball Non Liquid Sliding bearing with the same appearance under the same working conditions is very different. In addition, there are several different definitions of bearing “life”, one of which is the so-called “working life”,
which means that the actual life of a bearing before damage is caused by wear and damage, which is usually Non Liquid Sliding not caused by fatigue, but by wear, corrosion, seal damage and other factors.
The service life of ina bearing is in revolutions (or hours of operation at a certain speed). Definition: the bearing within this service life shall have Non Liquid Sliding preliminary fatigue damage (peeling or defect) on any bearing ring or rolling element.
However, no matter in laboratory test or in actual use, it can be clearly seen that the actual life of thrust ball bearing with the same appearance under the same working conditions is very different. In addition, there are several different definitions of bearing “life”,
one of which is the so-called “working life”, which means that the actual life of a bearing before damage is caused by wear and damage, which is usually not caused by fatigue, but by wear, corrosion, seal damage and other factors.