Bearing failure reasons

Since fretting on a raceway surface often looks similar to brinelling, it is sometimes called "false brinelling" (see Figure 4).

"Wear" occurs most frequently on sliding contact surfaces such as roller end faces and rib faces, cage pocket surfaces, and the guide surfaces of cages and bearing rings (see Figure 2 a)). Note, however, that wear caused by foreign matter or corrosion can affect not only sliding surfaces but also rolling surfaces (see Figure 2 b)).

Types of bearingfailures

"Scratching" refers to the development of relatively shallow marks caused by sliding contact, in the same direction as the sliding, and they are not accompanied by apparent melting of material (see Figure 7 a)). "Scuffing" refers to marks whose surfaces are partially melted due to higher contact pressure producing a greater heat effect (see Figure 7 b)). In general, you can think of scuffing as a more severe form of scratching.

"Cracking" is a collective name for things like splits and fractures. "Chipping," meanwhile, refers to defects that occur in a part of the rib of the bearing ring or in the corner of the roller. (See Figures 5 a) and 5 b).)

Bearing failure effects

In this part, from among the types of bearing failure listed in Table 1, we will explain the characteristics and the typical causes and countermeasures that can be taken for the following types:

In this part, we will call bearing visual defects "bearing failure," and we will explain the characteristics of bearing failure, its typical causes, and countermeasures that can be taken.

"Flaking" refers to the phenomenon in which material flakes from the raceway surface and rolling element surface due to rolling fatigue (see Figures 1 a) and 1 b)). The point at which this phenomenon occurs is the end of the bearing's service life. However, if flaking occurs earlier than expected, this can be considered an abnormality, which requires an investigation regarding the cause and also requires countermeasures to be taken.

"Fretting" refers to the phenomenon in which rust-colored wear particles develop on bearings that are subject to vibration while in a stationary condition (see Figures 3 a) and 3 b)).

Bearing failure Chart

Types of bearingfailuresand their causes

1) In "Bearing Failure (Part 2)," from among the various types of bearing failure, we explained the characteristics and the typical causes and countermeasures that can be taken for the following types:

What is the most common cause of bearing failure

3) If you have any technical questions regarding bearing failure, or opinions/thoughts on these "Bearing Trivia" pages, please feel free to contact us using the following form:

Table 1 shows the types of bearing failure and where they occur. Please refer back to Part 1 for the names of the various components of the bearing.

4) In "Bearing Failure (Part 3)," from among the various types of bearing failure, we will explain the characteristics and the typical causes and countermeasures that can be taken for the following types:

Bearing failure symptoms

・Correct the processing accuracy of the housing bore (take particular care to ensure the processing accuracy for split housings)

・Improve the centering accuracy・Widen the bearing internal clearance・ Correct the squareness of the shaft or housing shoulder

Please note that while the JTEKT rolling bearing catalog uses the terms "bearing" and "rolling bearing" interchangeably, this column does not use the term "rolling bearing" as a general rule.

"Brinelling" is a small surface indentation generated either (i) on the raceway surface through plastic deformation at the contact point between the raceway and rolling elements or (ii) on the rolling surfaces by the entry of foreign matter, when a heavy load is applied while the bearing is stationary or rotating at a low rotation speed (see Figures 6 a) and 6 b)). Nicks are those indentations produced directly by rough handling such as hammering.