| 摘要 |
PROBLEM TO BE SOLVED: To provide an injection device in a metal injection-forming machine with which a switchover from an injection process to a pressure-holding process can be carried out by rapidly decelerating the speed of an injection piston even without using a servo-control valve which complicates a hydraulic pressure circuit. SOLUTION: In a hydraulic pressure cylinder 9 for injection, holding the injection piston 10 for driving a screw 2 to the front part in the axial direction, a first chamber 11a and a second chamber 11b partitioned with the injection piston 10, are formed. The injection piston 10 is supplied to working oil into the first chamber 11a and on the other hand, is driven to the screw 2 into the front part in the axial direction by exhausting the working oil in the second chamber 11b from the second chamber 11b. In the second chamber 11b, the plurality of oil-exhausting holes 15a, 15b for exhausting the working oil are formed and at least a first oil-exhausting hole 15a therein, is fully or mostly plugged with the injection piston 10 in the interval while the injection piston 10 advances to the most-advancing position. COPYRIGHT: (C)2007,JPO&INPIT
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