Pre deformation and pre stress analysis of thin wall bearing

When the flexible bearing of harmonic reducer is assembled on the elliptical cam of wave generator, there is large prestress and pre deformation. Under the actual working load, prestress and pre deformation, the inner and outer rings of flexible bearing are analyzed, and their deformation, stress and load distribution are obtained

thin wall bearing

(1) The deformation of the inner and outer rings of the flexible bearing mainly depends on the contour line of the wave generator cam. The radial deformation of the inner ring is the largest at the long shaft and the smallest at the short shaft, but at nearly 45. Deformation at is 0. The radial deformation of the outer ring also has a similar distribution. The pre deformation of the outer ring is o at the long axis and the short axis, while at nearly 45. Is the maximum value, and the analysis results accord with the thin-walled ring theory. The maximum deformation of the inner ring is slightly larger than that of the outer ring. This is due to the contact deformation between the rolling element and the inner and outer rings, and there is a certain amount of approach.

(2) After the flexible bearing is assembled to the elliptical shaft cam, the maximum prestress of the inner and outer rings is the largest at the elliptical long shaft, and the maximum prestress of the inner ring is larger than that of the outer ring, mainly because the radius of curvature of the inner ring is smaller than that of the outer ring. The bending stress is large, which is consistent with the bending theory in material mechanics.

(3) Considering prestress, under the same radial load, the equivalent stress of the inner and outer rings of the flexible bearing is greater than that without prestress, which has a great impact on the rated bearing capacity of the flexible bearing.

(4) The fatigue life of flexible bearing is accurately calculated according to L-P theory. The results show that the fatigue life of flexible bearing is reduced by 30% considering prestress, which puts forward higher requirements for the design and manufacture of flexible bearing for harmonic reducer.

In other words, the equivalent stress at the inner and outer ring channel is mainly taken from the circumferential stress; The maximum equivalent stress and maximum radial stress of the inner and outer rings occur in the area where the ball at the long axis contacts the inner and outer channels.