Toshiba Kikai Kabushiki Kaisha

Hiroshi Kitamura

Makoto Tsuji

Norihiro Iwamoto

Noboru Fujiyoshi

A method for controlling injection in a die casting machine and apparatus for the same capable of producing high-quality die-casting products, which are not produced with fins, even in a high-speed cast or the use of the die with a low precision. A pressurizing controllable valve (21) is a flow adjustable type. A main spool (211) is structured to have a two-way valve (212) with a check-valve function and a position detector (213) for controlling servo, so that the flow of hydraulic fluid charged to a pressurizing cylinder device 20 is not controlled to be switched between ON-OFF but is allowed to adjustably flow, and a pressurizing process is controlled in response to a fin critical curve, thereby fins are previously avoided to be produced, thus producing the high-quality die-casting productions.

Method for controlling injection in a die casting machine and apparatus

A method and an apparatus for controlling an injection of a die-casting machine, the apparatus having an open-shut valve for opening and shutting a hydraulic channel through which hydraulic fluid is discharged from a boost cylinder device and a boost cylinder flow-control valve for regulating a flow of the hydraulic fluid discharged from the boost cylinder device. When a highly viscous molten material is injected toward a casting mold and the molten material reaches a gate of the casting mold, an injection resistance is increased. At this time, by regulating the hydraulic channel with the control valves to discharge the hydraulic fluid in accordance with a predetermined program, the boost cylinder device applies further pressure to the injecting piston to assist injection process, thereby preventing inappropriate change in injection speed. Consequently, the open-shut valve is opened to conduct ordinary pressure boosting pressure process.

A casting apparatus comprising a crucible furnace for containing a molten metal, a die assembly defining a die cavity having a casting volume for producing a die casting by forcing molten metal from the crucible furnace thereinto, an injection sleeve having a feed slot located therein, wherein the injection sleeve is vertically oriented for supplying the molten metal upwardly towards the die cavity, a feed block proximate to the injection sleeve and comprising a curved passage therein one end of which communicates with the feed slot, a feed pipe connected to the other end of the curved passage for providing fluid communication between the crucible furnace and the curved passage, feeder means for feeding the molten metal from the crucible furnace, through the feed pipe and the curved passage in the feed block, and through the feed slot into the injection sleeve. The present invention avoids the problems usually associated with the use of vertically oriented injection sleeve, such as oxidation of the molten metal, and solidification of molten metal upon the walls of the feed passage between the crucible furnace and the injection sleeve.

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Zama, Japan

Hiroshi Kitamura