| 摘要 |
PURPOSE:To form a rigid thread without using cutting in forming a thread on the inner diameter of a metallic cylinder by using a device made up of a main screw, three roller screws and a roller supporting bushing. CONSTITUTION:A device made up of a main screw 1, three roller screws 2 and a bushing 3 that supports the roller screws is used as a device to form a thread on inner side of a metallic cylindrical body 7. A side spur gear 8 is structured in a body with the main screw 1, and a taper hole, a taper shaft 5 and an adjusting screw are provided at the center of the main screw 1. Three cuttings 10 are provided vertically in the taper part to adjust diameter of the thread when the thread of the product is formed. The roller screws 2 make planetary movement by normal and reverse movement of the main screw 1. When rotating normally, thread is cut on the product, and when rotating reversely, thread on the product is reformed to complete forming of the thread. As forming is not made by cutting with a cutting tool, tape etc. chips are not generated and strength of the thread is excellent. |
