The contact behavior characteristics of the machine elements with spherical shape contacting each other, such as rolling element bearings, are formed in accordance with the contact theories revealed by Hertz. While Hertz put forward these theories, he made some assumptions. a-What are these assumptions? b-What is Hertz's theory of contact about roller bearing?
The contact behavior characteristics of the machine elements with spherical shape
contacting each other, such as rolling element bearings, are formed in accordance with the
contact theories revealed by Hertz. While Hertz put forward these theories, he made some
assumptions.
a-What are these assumptions?
b-What is Hertz's theory of contact about roller bearing?
(a)
According to the Hertz, the assumptions are given as,
(1)
The surfaces should be smooth and frictionless.
(2)
The bodies should be elastic and isotropic.
(3)
The contact area should be very small concerning the sizes of the bodies.
(4)
The strains generated on the body should be small and within the elastic limit.
(b)
Hertz theory of contact:
According to this theory about rolling bearing, the contact between two rollers or cylinders occurs as a line. It means, two rollers will make line contact with others. The resulting pressure between the two rollers will be infinite. And the surface will experience sudden yielding. But In real condition, when two rollers are pressed together, elastic deformation occurs at each roller surface and a contact area is created. The stresses that occur on these two surfaces be very high and sufficient to create failure. But stresses are not infinite.
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