Patent ID: 6629558
Filing Date: 2003-10-07
Classification: B22D

Abstract:
A die-casting machine comprising a sleeve through which molding material is injected into a cavity formed by a pair of mold dies, an injection plunger slidably mounted in said sleeve, an injection cylinder having an injection piston connected through a piston rod with said injection plunger, and a boost cylinder having a boost piston, said boost cylinder formed wits an inner diameter larger than an inner diameter of said injection cylinder and mounted adjacent to said injection cylinder thereon in a side opposite to said piston rod, wherein:said injection piston slidably engages an inner surface of said injection cylinder to thereby define a rod-side injection hydraulic chamber within said injection cylinder on a side of said injection piston adjacent to said piston rod, and a piston-side injection hydraulic chamber within said injection cylinder on a side of said injection piston opposite to said piston rod; said boost piston slidably engages an inner surface of said boost cylinder to thereby define an injection-side boost hydraulic chamber within said boost cylinder on a side of said boost piston adjacent to said injection cylinder, and a piston-side boost hydraulic chamber within said boost cylinder on a side of said boost piston opposite to said injection cylinder; said injection cylinder and boost cylinder are in fluid communication with a conduit connected to said rod-side injection hydraulic chamber and said injection-side boost hydraulic chamber and connected to a flow rate control valve arranged on a meter out side with respect to said cylinders, thereby controlling a speed of said injection plunger in accordance with a flow rate of pressurized oil flowing in said valve; and wherein said boost cylinder has a piston stroke at least equal to a plunger stroke corresponding to a volume of said cavity.