Abstract: A hydraulic circuit of an injection cylinder in a die-casting apparatus, which can achieve IN restriction and OUT restriction in a quickly switchable manner with a single circuit and which allows manufacturing of a high-quality molded product. The hydraulic circuit includes: a first pressure oil path supplying pressure oil to the injection cylinder; a second pressure oil path returning the pressure oil from the injection cylinder; a first flow control valve controlling a flow of the pressure oil through the first pressure oil path; a second flow control valve controlling a flow of the pressure oil through the second pressure oil path; a bypass pressure oil path connected to the second pressure oil path for bypassing the second flow control valve; a bypass on-off valve provided on the bypass pressure oil path and opening/closing the bypass pressure oil path with the pressure oil; and a controller controlling each valve.

Abstract: A die casting machine provided with an electric servomotor and a hydraulic cylinder as drive sources for injection is enhanced in operation stability in an injection step. In the injection step, the rotational speed of an injection electric servomotor (3) is pattern-controlled to follow a preset speed command pattern while the forward speed of a piston (5a) caused by driving of an injection hydraulic cylinder (5) is feedback-controlled with an addition signal of the forward speed of the piston (5a) caused by driving of the injection electric servomotor (3) and the forward speed of the piston (5a) caused by driving of the injection hydraulic cylinder (5). Alternatively, the forward speed of the piston (5a) caused by driving of the injection hydraulic cylinder (5) may be pattern-controlled to follow a preset speed command pattern while the rotational speed of the injection electric servomotor (3) is feedback-controlled with the addition signal.

Abstract: A hydraulic circuit of an injection cylinder in a die-casting apparatus, which can achieve IN restriction and OUT restriction in a quickly switchable manner with a single circuit and which allows manufacturing of a high-quality molded product. The hydraulic circuit includes: a first pressure oil path supplying pressure oil to the injection cylinder; a second pressure oil path returning the pressure oil from the injection cylinder; a first flow control valve controlling a flow of the pressure oil through the first pressure oil path; a second flow control valve controlling a flow of the pressure oil through the second pressure oil path; a bypass pressure oil path connected to the second pressure oil path for bypassing the second flow control valve; a bypass on-off valve provided on the bypass pressure oil path and opening/closing the bypass pressure oil path with the pressure oil; and a controller controlling each valve.

Abstract: A die casting machine provided with an electric servomotor and a hydraulic cylinder as drive sources for injection is enhanced in operation stability in an injection step. In the injection step, the rotational speed of an injection electric servomotor (3) is pattern-controlled to follow a preset speed command pattern while the forward speed of a piston (5a) caused by driving of an injection hydraulic cylinder (5) is feedback-controlled with an addition signal of the forward speed of the piston (5a) caused by driving of the injection electric servomotor (3) and the forward speed of the piston (5a) caused by driving of the injection hydraulic cylinder (5). Alternatively, the forward speed of the piston (5a) caused by driving of the injection hydraulic cylinder (5) may be pattern-controlled to follow a preset speed command pattern while the rotational speed of the injection electric servomotor (3) is feedback-controlled with the addition signal.