JP2821898B2 - How to prevent molten metal from entering the degassing valve - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing molten metal from entering a degassing valve in a die casting machine having a degassing valve for exhausting the inside of a cavity.

[Prior Art] Conventionally, in order to prevent intrusion of molten metal into a degassing valve, an injection stroke of an injection plunger is detected, and control is performed so as to close the degassing valve early so that the molten metal is released from the degassing valve. The degassing valve was closed earlier than the time to reach. Still, the high-speed injection time in the die casting machine is, for example, 0.01 to 0.1
The position setting of the limit switch for closing the degassing valve, which is as short as seconds, is very delicate, and often causes an accident that the molten metal intrudes into the degassing valve due to poor setting.

[Problems to be Solved by the Invention] However, even if the position of the limit switch is delicately set as described above, erroneous operation cannot be avoided.
If the molten metal is allowed to enter the degassing valve, the molten metal solidifies in the valve, so that the casting operation has to be stopped and the cleaning of the valve is difficult.

In view of such a problem, the present invention prevents erroneous setting and malfunction of a detection signal of a stroke position of an injection plunger by a limit switch or the like, and ensures gas release from a mold cavity, as well as a gas release valve. It is an object of the present invention to provide a method for preventing intrusion of molten metal into steel.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method of opening a degassing valve by the first signal of a stroke position signal by an injection plunger, closing the degassing valve by the next signal, Only when a high-speed injection signal is received after receiving the closing signal, the injection plunger is interlocked so that high-speed injection can be performed. The hydraulic circuit for moving the plunger is shut off, and a warning is issued by a lamp or a buzzer.

[Operation] The degassing valve is opened by the first signal of the stroke position signal by the injection plunger, the degassing valve is closed by the next signal, and only when the high-speed injection signal is received after receiving the closing signal, the high speed of the injection plunger. If the injection valve is interlocked and the high-speed injection signal is received and the degassing valve closing signal has not yet been received, the hydraulic circuit that moves the injection plunger is shut off and a warning is issued by a lamp or buzzer. Accordingly, when the high-speed injection of the injection plunger is transmitted earlier than the closing operation start signal of the degassing valve, the injection operation is stopped at that time, so that the molten metal does not enter the degassing valve.

[Embodiment] An embodiment of the present invention will be described in detail with reference to FIG.
In FIG. 1, the vent valve 1 is attached to a mold 7. Reference numeral 2 denotes a valve of the degassing valve 1, which is connected to the piston 3 of the cylinder 4.

The state shown in FIG. 1 is a state in which the valve 2 of the degassing valve 1 is opened, and the degassing valve 1 is operated by the solenoid valve 5 and is evacuated from the exhaust port 6 to a vacuum device (not shown) or the atmosphere. Is done. Reference numeral 8 denotes a cavity defined in the mold 7, and 9 denotes an injection sleeve mounted on the mold 7. Injection plunger 10 integrated with rod 10a
Is slidably fitted to the injection sleeve 9. Reference numeral 11 denotes an injection cylinder, which is integrally formed with a piston 11a slidably fitted to the injection cylinder 11, a dog 19, a piston rod 11
b, a drive source for moving the injection plunger 10 via the rod 10a. Reference numeral 12 denotes the molten metal injected into the injection sleeve 9, and the state shown in the figure shows a state in which high-speed injection is about to be started. Reference numeral 13 denotes an accumulator, and a required pressure oil amount is charged as energy by a charging circuit. Reference numeral 15 denotes an injection speed adjusting valve for switching the injection speed of the injection cylinder 11 between a low speed and a high speed.Since the solenoid valve 17 is excited to secure a flow path in a slightly right line of the piston 15a, the pressure oil of the accumulator 13 is injected. The injection cylinder is adjusted to a small volume through the speed control valve 15 and is
The cylinder 11 moves forward at a low speed and the ball 15b moves to the right by the excitation of the solenoid valve 18 so that the pressure oil of the accumulator 13 is adjusted to a large capacity by the injection speed adjustment valve 15, and the opening / closing valve It flows through 16 to the injection cylinder 11 to advance the same cylinder 11 at high speed.

In the opening / closing valve 16, a small amount of oil flows from the injection speed adjusting valve 15 when the solenoid valve 18 is not excited, and when the solenoid valve 18 is excited, the ball 16b goes right and the injection speed adjusting valve 15 becomes larger. A volume of oil flows.

Limit switches 20 to 22 are
Is a stroke position detection signal generating means. Dog 19
Is provided on the piston rod 11b of the injection cylinder 11 so as to engage with the limit switches 20 to 22.

Next, the operation of the present invention will be described with reference to FIG. When the relay 30 is activated by the low-speed injection start signal 30c, the injection cylinder 11 moves forward at low speed by excitation of the solenoid valve 17 and a solenoid valve (not shown).

As the injection cylinder 11 advances, the injection plunger 10
Moves forward, and the dog 19 operates the limit switch 20, the solenoid 5a is turned off via the relay 23, and the lowering of the piston 3 connects the cavity 8 to the atmosphere or a vacuum device.

When the dog 19 activates the limit switch 21 by the advance of the injection plunger 10, the valve 2 is closed (upward in FIG. 1) by operating the relay 23 to turn on the solenoid 5a, so that the gas release valve 1 is closed. It is supposed to.

Further, when the injection plunger 10 moves forward and the limit switch 22 is operated by the dog 19, the high-speed injection signal 22
a is input to the AND circuit 25 of the interlock circuit 24.

Here, if the set position of the limit switch 22, that is, the position of the switch 22 is after the position of the limit switch 21, the signal 22a of the limit switch 22
At the same time, the signal 21a of the limit switch 21 has already been transmitted and becomes the signal 21b via the holding circuit 26 and is input to the AND circuit 25. Activate 27, relay 28
To work. When the contact of the relay 28 is closed, the solenoid valve 18 is excited, the injection speed adjusting valve 15 is fully opened by the rightward movement of the ball 15b of the injection speed adjusting valve 15, and the injection plunger 10 is injected at high speed (leftward in FIG. 1). be able to. In this manner, the injection plunger 10 is interlocked so that high-speed injection can be performed only when a closing signal of the gas release valve 1 is received.

In this case, if the closing signal 21b of the gas release valve 1 is not transmitted, the AND circuit 25 does not transmit the signal 25a, so the relay circuit 27 does not operate the relay 28, and operates the relay 29. The excitation is turned off, the injection speed adjusting valve 15 is rapidly shut off, and the forward movement of the injection plunger 10 can be suddenly stopped. At the same time, an alarm can be transmitted by the lamp 30a and the buzzer 30b.

[Effects of the Invention] According to the present invention described above, since the degassing valve closing signal and the high-speed injection signal are interlocked, it is possible to prevent molten metal from entering the degassing valve due to erroneous setting or malfunction. it can.

[Brief description of the drawings]

 FIG. 1 is a block diagram of one embodiment of the present invention. 1 Gas vent valve 10 Injection plunger 15 Injection speed adjustment valve 16 Closing valve 19 Dog 20 Gas vent valve opening signal limit switch 21 Gas vent valve closing signal limit switch 22 High-speed injection signal limit switch 24 Interlock circuit 25 AND circuit 29 Lamp 30 Buzzer

Claims (1)

(57) [Claims] 1. A method for preventing the intrusion of molten metal into the degassing valve of a die of a die casting machine having a degassing valve, the method comprising: opening the degassing valve with a first stroke position signal from an injection plunger; The gas vent valve is closed by the signal of, the interlock is performed so that high-speed injection of the injection plunger can be performed only when the high-speed injection signal is received after receiving the close signal, and when the high-speed injection signal is received, When the closing signal of the degassing valve has not yet been received, the hydraulic circuit for moving the injection plunger is shut off, and a warning is issued by a lamp or a buzzer. How to prevent.