| 摘要 |
A method for manufacturing a single-piece type valve sleeve, includes plastic-working a workpiece thereby to form in the workpiece a blind bore and a plurality of grooves in the surface of the bore and extending lengthwise of the bore, plastic-working a portion of the workpiece at the bottom of the bore so as to form a through hole in the workpiece, and plastic-working an inner portion of the workpiece adjacent the mouth of the bore thereby to close one end of the grooves. A single-piece type valve sleeve is produced by the method. |
