JPH08168867A - Device for pulling out core in die casting - Google Patents

Abstract

PURPOSE: To easily pull out a movable core from a cast product even by a comparatively small size core cylinder by connecting a servo valve to piping for supplying working oil to the core cylinder connected to the movable core, operating the servo valve at the time of pulling out the core and giving vibration to the working oil in the core cylinder. CONSTITUTION: At the time of supplying the working oil into a hydraulic chamber 4a for inserting the core through one side piping 5a, a piston 3 is shifted to the core inserting side and the movable core 2 is set at the prescribed position of a metallic mold through a rod 1a. Further, at the time of supplying the working oil in a hydraulic chamber 4b for returning back the core through the other side piping 5b, the piston 3 is shifted to the core return-back side and the movable core 2 is pulled out from the cast product through the rod 1a. Further, the servo valve 6 is connected to the pipings 5a, 5b for supplying the working oil into the cylinder 1 for core, and the vibration is given to the working oil in the cylinder 1 for core at the time of pulling out the core and the piston 3 and the rod 1a are finely vibrated in the axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core extracting device for a movable core incorporated in a mold in die casting.

[0002]

2. Description of the Related Art When a movable core incorporated in a die casting mold is pulled out from a cast product, the cast product clings to the movable core as the molten metal solidifies and shrinks. Requires pulling force. Therefore, conventionally, a large-sized core cylinder has been used, or a booster has been incorporated in the core cylinder. However, when a large-sized core cylinder is used, the insert and pull-out operations of the core become slow, which prolongs the casting cycle, lowers productivity, and requires a large installation space. In addition, when a pressure booster is incorporated, the cast product is subject to excessive force, so that the cast product is easily distorted or cracked.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is relatively small in size without using a large-sized core cylinder or incorporating a booster. (EN) A core extracting device for die casting in which a movable core can be easily extracted from a cast product even in a core cylinder.

[0004]

A core withdrawal device for die casting according to the present invention, which achieves the above object, has a servo valve in a pipe for supplying hydraulic oil to a core cylinder connected to a movable core. Is connected, and when the core is pulled out, the servo valve is operated to give vibration to the hydraulic fluid in the core cylinder.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the schematic drawings. In the figure, reference numeral 1 is a core cylinder, and a movable core 2 is connected to its rod 1a.

A piston 3 integrated with a rod 1a is slidably incorporated in the core cylinder 1 as in the conventional case, and the core-containing hydraulic chamber 4 is located on the head side with the piston 3 as a boundary.
a is formed and a core return hydraulic chamber 4b is formed on the rod side, and these core-containing hydraulic chamber 4a and core return hydraulic chamber 4b are formed.
Pipes 5a and 5b for supplying hydraulic oil are connected to each other.

Therefore, when hydraulic oil is supplied into the core-containing hydraulic chamber 4a through the one pipe 5a, the piston 3 moves to the core-containing side (the right side in the drawing), and the movable core 2 moves through the rod 1a. The core return hydraulic chamber 4b is set at a predetermined position of a mold (not shown), and through the other pipe 5b.
When hydraulic oil is supplied to the inside, the piston 3 moves to the core return side (left side in the drawing), and the movable core 2 is pulled out from the cast product via the rod 1a.

A servo valve 6 is connected to the pipes 5a and 5b for supplying the working oil to the core cylinder 1 so that the working oil in the core cylinder 1 is vibrated when the core is pulled out. Then, the piston 3 and the rod 1a are vibrated finely in the axial direction (the direction in which the core is inserted and returned).

That is, in the first embodiment shown in FIG. 1, a well-known servo valve 6 is connected to the pipe 5b connected to the core return hydraulic chamber 4b side of the core cylinder 1 to connect the core to the core. When returning, vibration is applied to the hydraulic oil in the core return hydraulic chamber 4b,
The piston 3 and the rod 1a are finely vibrated in the axial direction (the direction in which the core is inserted and returned).

In the second embodiment shown in FIG. 2, the pipe 5a connected to the core-containing hydraulic chamber 4a side of the core cylinder 1 and the pipe connected to the core return hydraulic chamber 4b side. A well-known servo valve 6 is connected to 5b, and hydraulic oil is alternately supplied into the core-containing hydraulic chamber 4a and the core-returning hydraulic chamber 4b at the time of core return so that the hydraulic oil in both hydraulic chambers 4a and 4b is supplied. By vibrating, the piston 3 and the rod 1a are vibrated finely in the axial direction (the direction in which the core is inserted and returned).

When the servo valve 6 is operated at the time of pulling out the core, the working oil in the core-containing hydraulic chamber 4a and / or the core returning hydraulic chamber 4b is vibrated by operating the servo valve 6. , The piston 3 and the rod 1a vibrate finely in the axial direction (retracting direction of the core), and as a result, the movable core 2 connected to the rod 1a also vibrates finely in the reciprocating direction of the core.

[0012]

Since the core withdrawing device for die casting according to the present invention is constructed in this manner, the piston and rod of the core cylinder vibrate finely in the axial direction (the direction in which the core is inserted and returned) during core extraction. As a result, the movable core connected to the rod also vibrates finely in the direction in which the core moves in and out,
It becomes easy to come off from the cast product.

By the way, when die casting is performed using an existing die and the pulling force of the movable core at that time is measured,
What was 500 Kgf to 600 Kgf was 250 Kgf to 450 Kgf when it was pulled out while vibrating the hydraulic oil in the core cylinder. As can be understood from this, according to the core extracting device of the present invention, a small core cylinder can be used without using a large core cylinder or incorporating a booster. The movable core can be easily pulled out from the cast product.

Moreover, since it is only necessary to connect the servo valve to the pipe for supplying the hydraulic oil to the core cylinder, the cost is low and the maintenance is easy.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a second embodiment of the present invention.

[Explanation of Codes] 1: Core cylinder 1a: Rod 2: Movable core 3: Piston 4a: Core-containing hydraulic chamber 4b: Core return hydraulic chamber 5a, 5b: Piping 6: Servo valve

Claims (1)

[Claims] A servo valve is connected to a pipe for supplying hydraulic oil to a core cylinder connected to a movable core, and the servo valve is operated when the core is pulled out to operate in the core cylinder. A core extracting device in die casting, characterized by giving vibration to oil.