To provide a method for manufacturing a ball screw that facilitates formation of a recessed groove, constituting a ball circulation passage, by using a die while prolonging the lifetime of the die.
The inner-peripheral surface of a blank 21 is formed with a recessed groove 22 comprising a main groove 22a, constituting a ball circulation passage 11, and an extension groove 22b extending from both ends of the main groove. The end of the extension groove 22b is formed into a shape that satisfies the following conditions. The condition A: The tip of the extension groove 22b has a substantially spherical shape and its curvature radius is larger than half of the width of the main groove 22a. The condition B: The arcuate boundary line of the tip of the extension groove 22b formed on the inner-peripheral surface is formed at a position further apart from the main groove 22a than a position that passes the part to be the connection point between the main groove 22a and a screw groove 5a. The condition C: The arcuate boundary line of the tip of the extension groove 22b formed on the inner-peripheral surface is formed at a position closer to the main groove 22a than a position that passes the apex of a virtual semicircle whose radius is half of the width of the main groove 22a.
| JP2008281063A | 2008-11-20 | |||
| JP2007092968A | 2007-04-12 | |||
| JPH1082458A | 1998-03-31 | |||
| JPH08257669A | 1996-10-08 | |||
| JP2008281063A | 2008-11-20 |
Hide Tanaka Tetsu
Ichi Hirose
Toru Miyasaka