For the five kinds of swing head motion trajectories in the figure, they are analyzed one by one as follows:
(1) When the circular motion track is adopted, the angle between the swing head axis and the lower die axis is always kept constant, and the contact area rate is always kept constant under the condition of uniform feeding. At this time, the acting point of the resultant force of the forming force makes a circular motion with equal speed and equal diameter. Therefore, the rolling process is stable and the deformation is uniform, which is especially suitable for the rotating body.
(2) The rosette trajectory is theoretically suitable for forming parts with tooth profile. However, the included angle between the swing head axis and the lower die axis is 0- γ In theory, there is a “dead zone”, and the deformation uniformity is not as good as the circular motion track. At the same time, the more the number of lobes and the faster the frequency, the greater the vibration of the rotary rolling machine, which will have an adverse impact on the equipment.
(3) When the double circle motion track is adopted, its characteristics are similar to the rose line track, and there is also a “dead zone”, but the non-uniformity of deformation and the vibration of rotary rolling machine are less than the rose line track.
(4) The characteristics of spiral trajectory are between the characteristics of circular trajectory and rose trajectory. It is suitable for the axial and radial flow of blank metal. The center forming is better, and it is suitable for forming parts with complex central section shape. Theoretically, when the spiral motion path is selected, the forming performance of the gear is the best, the deformation of each part of the gear is uniform and easy to fill. However, the acting point of the resultant force of the forming force makes a variable-speed spiral motion, which is the same as the rose motion. The swing rolling process is unstable, has high requirements for the strength of the equipment, and reduces the service life of the equipment.
(5) When the linear motion path is adopted, the swing head moves back and forth in a straight line and always contacts only the end face of the workpiece in the straight line area, so it is suitable for forming parts with long axial size.
Based on the above analysis, the circular motion track is the best for the cold rotary forging of.