How does the centering device of the thread rolling machine work?

At present, the thread rolling machine tools at home and abroad generally do not have a centering device for thread rolling when they leave the factory. There is only a flat support plate for placing the workpiece. This creates a problem. When the wave pressure is applied to a short section of thread on a longer workpiece, the workpiece will inevitably swing. For the first-level precision thread, the size of the thread will exceed the tolerance and the thread parameters will not meet the technical requirements.

The centering device mentioned here is based on the characteristics of the thread. On the basis of not affecting the production efficiency, it uses the thread groove support plate with an automatic recovery mechanism to better solve the problem of workpiece positioning.

Device structure and working principle

When the thread rolling machine with a flat support plate is used to roll the thread, the workpiece swings mainly because the size of the workpiece blank changes during the rolling process. As the thread tooth shape gradually forms, the center of the workpiece is constantly raised, causing the rear end of the workpiece to be suspended and lose support, thus swinging. At the same time, with the wave pressure, the center of the workpiece is also constantly shifting toward the direction of the static rolling wheel. However, due to the radial rolling force of the roller, the lateral swing of the workpiece is restricted, so the elimination of the workpiece swing is mainly to eliminate the longitudinal offset of the center line of the workpiece.

The structure of the groove support plate centering device. It is mainly composed of a thread groove support plate bracket spring, etc. Some thread grooves are machined on the surface of the thread groove support plate so that the tooth shape formed during the rolling process of the workpiece is embedded in the thread groove, thereby effectively ensuring that the center height of the workpiece does not change. When the rolled tooth shape and the thread groove are embedded, a screwing movement similar to that of a bolt and a nut is formed. When the threads are screwed together, there will be relative movement, so the thread groove support plate must have axial movement. For this reason, springs are designed at both ends of the thread groove support plate to achieve automatic axial recovery.