The definition of bearing life and related theory

In the process of mechanical design, engineering and technical personnel paid great attention to the life of rolling bearing. In fact, what is called the bearing life in the field of engineering technology usually refers to the bearing fatigue life. Bearing the carriage, load from one bearing ring reached another through the rolling element bearing ring. Inside the metal material will appear the corresponding stress distribution, roughly diagram as shown in the figure below. As you can see, in the following picture in the rolling element and raceway contact surface of metal materials under a certain depth in the biggest shear stress. Each roller rolled groove, the shear stress will appear again and again. When there is a number to a certain amount of time, the metal will appear fatigue, thus began to fail. Regardless of the material, the shear stress of the reciprocating were always there, just in time and the number of roller rolled and is proportional to the positive pressure ( The life behind the calculation formula of the relationship between the) 。 After the initial fatigue points appear, fatigue will be the certain direction to the spread of the metal surface, end up bearing metal surface spalling. This is a very typical in bearing failure mode of a surface fatigue spalling. The description of the course of the bearing failure is the fatigue failure of bearing. And under the given conditions, the bearing fatigue failure time ( Turn the circle) That is what we call the fatigue life. In fact, each bearing has its fatigue limit. But even under the same conditions, due to the bearing internal uniformity of metal materials, etc. , for a large number of bearing is not likely to have exactly the same fatigue life. So we introduce the concept of reliability coefficient.