| 摘要 |
<p>PURPOSE:To make a groove formable with press work by means of simple rectilinear motion, by installing a part, where a bottom surface is tilted to an axial direction, in an axial groove, in case of a valve sleeve forming plural axis grooves, whose longitudinal, both ends are closed each, in an inner surface. CONSTITUTION:At the time of manufacture of a valve sleeve to be rotatably installed in the periphery of a valve rotor of a hydraulic rotary valve available for a power steering or the like, first of all, a bottomed cylindrical blank 8 is machined by a press. Next, this cylindrical blank 8 is set up in a press die 10 having a taper surface 10c in an intermediate part, and press work is carried out with a punch 12 consisting of a punch member 16 being held by a punch pin 14 and plural notches 14a forming an outer circumference of the said pin 14 and having each bottom surface 14b tapered. At the time of this press work, the punch member 16 is projected outward in a radial direction along the said bottom surface 14b, whereby an axial blind groove 8f having a pair of inclines 8h comes to be formed in an inner surface of the blank 8 in this way.</p> |
