| 摘要 |
PURPOSE:To manufacture easily a valve sleeve having a blind groove on its inside surface by forming plural grooves in axial direction on the inside surface of a cylindrical body and by compressing an expanded part of the cylindrical body to the same caliber as that of a non-expanded part. CONSTITUTION:When a raw material is worked by pressing with the use of a punch 4, a bottomed cylindrical body having an opening part 3a expanded to the outside is obtd. and six lines of a groove 11 are formed. The groove 11 is shorter than the axial direction length of the inside surface of the bottomed cylindrical body 3 and is made a blind groove, both ends of which are sealed. The punch 4 is then removed and as the 2nd stage, an expanded part 3a of the opening side is compressed to the practically same caliber with that of a cylindrical non-expanded part 3c. Namely when the expanded part 3a on opening side of the cylindrical body 3 is pressed with the 2nd punch 12 it is pushed inside a round hole part 2a of the lower part than a tapered surface 2b of a press die 2 and is compressed to the same outer diameter with that of the non-expanded part 3c. Simultaneously the inner diameter of the opening part 3a too becomes practically the same with that of the non-expanded part 3c.
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