Assembly method of flexible bearing of harmonic reducer
Harmonic reducer flexible bearing is a kind of harmonic reducer bearing. It is a kind of bearing used outside the wave generator, which can realize the speed change requirement of large transmission ratio. Because of its special overall structure, it is different from other bearings.
1. Conventional ball filling
Traditionally, the filling method of finishing a ball is to apply radial force to the outer ring between the filling Angle of 186 to 195° to make the ball elastic deformation. Although this method is very common, there are still some problems such as the clamping of the ball and the plastic deformation of the ring.
2. Circular ball filling groove method
When the ball filling Angle is more than 195°, a circular arc groove larger than the diameter of the steel ball is opened between the inner and outer rings and the bottom diameter of the groove. During assembly, the steel ball is filled into the groove one by one. This method has low assembly efficiency, high production cost and difficult quality control. If the filling groove is deep, the ring will be scrapped. The opening is too shallow to fill the ball. The grooving also has a certain effect on the bearing performance, which mainly reduces the high-speed performance greatly, and the axial channeling is also limited.
3. Fracture method
When the ball filling Angle is greater than 195°, and the bearing operating conditions are low, and the speed and vibration requirements are not high, the fracture ball filling method is used. Before the heat treatment of the outer ring, a small groove should be cut in the inner diameter to generate stress concentration through the heat treatment. When the grinding of the outer ring is finished, the outer ring should be cracked. Fill the ball by expanding the outer ring to fill the steel ball to be filled. This is a way of increasing the number of balls filled at the expense of bearing performance.
4. Elastic loading method
The so-called elastic loading principle is a method to fill the groove by expanding the radial deformation of the bearing ring within the allowable tensile stress. The force is mainly applied to the end face of the outer ring, and when the outer ring is pressed down, the steel ball will continuously expand the outer ring, turning into the radial tension of the steel ball on the outer ring. With the increase of the pressing distance, the number of steel balls involved will also increase, and the tension of the outer ring will also increase, until the steel ball is completely opened and enters the channel. The stress process is shown in the figure. The method can satisfy the filling requirement of 360° ball Angle theoretically.