| 摘要 |
A method of manufacturing a single-piece valve sleeve, including the steps of: plastic-working a workpiece thereby to form in the workpiece a blind bore the a plurality of grooves in the surface of the bore, the grooves extending lengthwise of the bore and having one closed end at the bottom of the bore and an open end at the mouth 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 form an uplift portion so as to close the open end of the grooves wherein the inner portion of the workpiece is press-deformed with a punch and the uplift portion is guided by a mandrel from opposite direction of the punch. |
