JPS58132361A - Residual pressure remover of hydraulic cylinder for movable core in die casting machine - Google Patents

Abstract

PURPOSE:To remove the residual pressure in a hydraulic cylinder for a movable core thoroughly and to eliminate labor and time by sensing the stoppage of a motor for a hydraulic pump and operating the solenoid valve of said cylinder selectively to feed and return states. CONSTITUTION:A motor for a hydraulic pump operates and the feed valve 2a and return valve 2b of a solenoid valve 2 for a core are operated by relays during the operation of a die casting machine, whereby a hydraulic cylinder 1 for a movable core is operated. The cylinder 1 stops as well when the motor for the hydfaulic pump is stopped in order to stop the die casting machine. The stoppage of the motor for the hydraulic pump in this stage is sensed with a sensing part A for stoppage of the motor, and the solenoid valve 2 of the cylinder 1 is operated selectively to the feed and return states by the command of an instructing part B for operation, whereby the residual pressure in the cylinder 1 is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a residual pressure relief device for a hydraulic sill for a movable core in a die casting machine.

Hydraulic cylinder for movable core (The hydraulic line for operating this is connected to the hydraulic line for operating the die-casting machine, and is operated by the solenoid valve for core (2). Therefore, when the hydraulic bong motor for supplying pressure oil to the above-mentioned hydraulic system path is stopped, both the hydraulic circuit and the electric control circuit are stopped, and the solenoid valve for the core (2) is in a neutral state and stopped. (See Figure 1).

Therefore, the pressure oil remains trapped inside the hydraulic cylinder for movable core (υ) and the hose part (3), and the check valve material coupler (4) of the hydraulic cylinder for movable core (1) remains trapped. )
cannot be moved by human power. That is, the hydraulic cylinder for the movable core (1), the solenoid valve (2), and the coupler with a safety check valve are connected through the hose (3) to prevent oil from flowing out when the hose is pulled out. Therefore, once the hose (
When 3) is pulled out from the check holder (4), the comb is removed by the pressure oil in the movable core hydraulic cylinder (1).
The check valve (5) inside (4) no longer operates, making it impossible to connect the hose (3) again with human power.

Therefore, in the past, the core solenoid valve (2) was pushed by hand or with a stick, or the check valve was sealed by a check valve sealer (see Fig. 1(b)).
The pressure oil (residual pressure) inside the movable core hydraulic cylinder (1) and the hose part was removed by opening the 9F (5) of the chamber (4) with a hammer (6).

However, such conventional residual pressure release methods are all manual and therefore time consuming, oil scatters around the worker and pollutes the work site, and the residual pressure is not completely removed. There are 6 inconveniences that you can't avoid.

In view of these conventional inconveniences, the present invention has developed a hydraulic cylinder for a movable core, which has a zero residual pressure after the die casting machine has stopped, that is,
It is an object of the present invention to provide a device that can stop a hydraulic pump motor and automatically and completely release pressure after death.

An example of implementing the present invention will be described below based on FIG. 2.

While the die-casting machine is operating, the hydraulic pump motor operates, and the relay operates the solenoid valves for the core (Nono pulp (2a) and return 9 pulp (2b)), and the hydraulic sill for the movable core operates. (1) operates, but when the hydraulic pump motor is stopped in order to stop the die-casting machine, the movable core hydraulic cylinder (1) is also stopped.

The stop of the hydraulic pump motor is sensed by the motor stop sensing unit (~), and then the solenoid valve (2) of the hydraulic cylinder (1) for the movable core is activated by a command from the operation instruction unit (b) to return to the return state. The hydraulic cylinder for the movable core (
1) It is designed to relieve the residual pressure inside.

The motor stop detection unit consists of a motor operation relay (MR) and a motor stop confirmation timer (To), and when the relay contact (7) of the motor operation relay (MR) becomes oFi, the stop pipe of the hydraulic pump motor is activated. The motor stop confirmation timer (
To) starts operating, and the timer contact (8) turns ON.
Instructs the operation instruction unit 0 to perform a pressure relief operation.

Operation instruction section (time is Ji-tance control and timer ('I'1)
) (T heavy), and when the timer contact (8) is turned on by the motor stop confirmation timer (T・), the pressure release timer ('f't) operates and the timer contact (9) is turned on. Timer for working and core insertion timing (Ts
), the relay (φ2) t- for the core insertion command is activated first, and then the relay V-(÷1) for the core return command is activated.

When the core insertion command relay (φ2) operates, the relay contact (10a) becomes 1 and ((2a-1), (2m-2))
, the inserting pulp (2a) of the core solenoid valve (2) operates to enter the core inserting state. At this time, the hydraulic pump is actually stopped, so the hydraulic cylinder (1) for the movable core does not operate, and instead, the pressure oil on the core return side (llb) drains and returns to the tank. The pressure is released to the same level (0~).

Next, the core return command relay (φ1) operates, and the relay contact (10b) turns ON ((2b-1), (21)
-2)) and the return pulp (2b) operate to return the core. Then, the pressure oil on the side where the core enters (lla) drains and is relieved to the same level as the tank (0~), and finally the pressure relief timer (Ts) stops and the movable core hydraulic cylinder (1) Complete the residual pressure release operation inside.

In this way, the present invention includes a motor stop sensing section that detects the stop of a hydraulic pump motor, and a command from the motor stop sensing section that turns on the solenoid valve of the hydraulic cylinder for the movable core and switches it to the return state to avoid the operation. When the hydraulic pump motor stops to stop the die-casting machine, the solenoid valve of the hydraulic cylinder for town moving cores is automatically switched to the human or return state for a certain period of time. Residual pressure in the hydraulic cylinder for the movable core can be completely released. Therefore, all the inconveniences and drawbacks of the conventional system can be eliminated and the desired purpose can be achieved.

[Brief explanation of drawings]

Fig. 1 (&) is a conceptual diagram of a hydraulic cylinder for four cores, Fig. 1 (b) is a diagram illustrating a conventional pressure relief operation, and Fig. 2 is a circuit diagram of the device of the present invention. . In the figure, (1) is the hydraulic cylinder for the movable core, (2) is the solenoid valve for the core, ■ is the motor stop sensing section, and (c) is the operation instruction section0 Patent applicant Fuso Light Alloy Co., Ltd.

Claims (1)

[Claims] It consists of a motor stop sensing section that detects the stoppage of the hydraulic pump motor, and an operation instruction section that switches the solenoid valve of the hydraulic cylinder for the movable core to the loading and returning states based on the command from the motor stop sensing section. Residual pressure relief device for hydraulic syringe for movable core in die-casting machines that use mold as mold.