JPH02192866A - Mechanism for preventing bound of vent valve for venting device in injection-molding machine - Google Patents

Abstract

PURPOSE:To eliminate bound of a vent valve and to make sure of shut of a venting hole by constituting the vent valve as fitting an absorb plate at the suitable place of the vent valve so as to rise with the vent valve at the time of moving the vent valve. CONSTITUTION:By supplying air into an air chamber (a) through a hose 17, elbow 16 and air supplying hole 15, a piston 13 is pushed up. The vent valve 6 held to valve opening position with stopper means composed of steel balls 8 and springs 9 is shifted upward together with the piston 13 and the venting hole 3a is shut with a valve head 6a, and valve 1 for venting system is made to valve shutting state. However, step part 6e in the vent valve 6 is collided to lower end face 11a of the absorb plate 11, and the absorb plate 11 is flown upward to absorb kinetic energy of the vent valve 6 into the absorb plate 11. In this result, as the kinetic energy of the vent valve 6 is reduced, the bound of the vent valve is eliminated, and the venting hole 3a is surely shut with the valve head 6a.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an exhaust valve bounce prevention mechanism of a degassing device for extracting gas from a mold cavity in a die casting machine, an injection molding machine, etc. during injection molding.

[Conventional technology]

In an injection molding machine or the like, if gas remains in the mold cavity during injection molding, this causes the formation of blowholes in the product, so it is necessary to discharge the gas to the outside of the mold.

Conventionally, various structures have been proposed as the above-mentioned gas venting device. For example, in Japanese Patent Publication No. 59-309, a single valve is disposed in the exhaust passage led from the cavity of the mold, and the valve is directly closed by the inertia of the molten metal during injection molding. Further, in Japanese Patent Application Laid-Open No. 60-82262, a detection valve and an exhaust valve are integrally provided in an exhaust passage communicating with a cavity of a mold, and A configuration is disclosed in which the exhaust valve is arranged at right angles in the lateral direction, and after the detection valve closes due to the pressure of the molten metal, the exhaust valve is closed through pressure feeding of air from the detection valve.

Furthermore, as a conventional example using a detection sensor,
Publication No. 9-130670 and Japanese Unexamined Patent Publication No. 185262/1983
No. 60-79828 filed by the present applicant.

JP-A-59-130E370 relates to a mold degassing device that can reliably prevent molten metal from flowing into the valve from the exhaust path regardless of the molten metal injection speed. A molten metal detection sensor consisting of a temperature sensing element is provided inside, and air is switched based on a detection signal from this detection sensor to close the valve.

Furthermore, in Japanese Patent Application Laid-Open No. 61-165262, a molten metal detection sensor (temperature sensor, energization sensor, or gas ejection sensor) is installed in the cavity of the mold, and an actuator is actuated by the detection signal of the molten metal detection sensor to close the mold. A configuration in which the valve is operated is disclosed.

Furthermore, in Utility Application No. 6O-7982E3, a molten metal detection sensor is installed in the exhaust passage, and an electric circuit connected to the molten metal detection sensor switches the flow of air into the cylinder and closes the valve. The configuration is disclosed.

In the conventional device described above, a single valve or a detection valve,
Or, when any valve such as an exhaust valve is closed by the molten metal, it collides with the valve seat of the valve body, causing the valve to bounce and cause the valve to move in the closing direction.4.4
u/sec,, 3.8 mm/in bounce time
It takes a total of about 8 mm/see,
During the bounce, the molten metal moves at a high speed, so the molten metal flows into the valve body from the exhaust port, causing various problems such as valve non-operation, and the valve operation time is long due to the bounce time, so the exhaust Since it is necessary to slow down the flow rate of the molten metal through the channel, this is one of the causes of product defects such as poor circulation.

Furthermore, since it is necessary to lengthen the exhaust path to prolong the time it takes for the molten metal to reach the valve, there are problems such as an increase in the amount of returned material, which is one of the causes of a decrease in product yield.

[Problem that the invention seeks to solve]

The present invention is an attempt to solve the above-mentioned problems.The present invention is constructed by attaching an absorbing plate to an appropriate position of an exhaust valve so that it is lifted up by the exhaust valve when the exhaust valve closes, thereby causing the exhaust valve to close. When the exhaust valve is operated, the kinetic energy of the exhaust valve is absorbed by the absorbing plate, causing the exhaust valve to bounce. Its purpose was to ensure closure.

[Means for solving problems]

That is, the present invention provides an injection molding machine in which an exhaust system valve is disposed in an exhaust passage led from a mold cavity. This is an exhaust valve bounce prevention mechanism for a degassing device in which an absorber plate is attached to the appropriate position of the exhaust valve, which is slidably attached to the exhaust valve body so that the exhaust port can be opened and closed, to prevent collision when the exhaust valve closes. Attach the absorber plate so that it can be moved.
The above-mentioned problem was solved by constructing a 7-busorb case for a guide and stopper disposed coaxially with the exhaust valve body.

〔Example〕

Detailed explanation will be given below based on the drawings showing an embodiment of the present invention. In FIGS. 1 and 2 showing an exhaust system valve 1, an exhaust hole 3 perpendicularly formed in the center of the exhaust valve body 2 is shown. and,
A cylindrical exhaust valve 6 is slidable in the axial direction into the valve hole 5 of the exhaust valve guide 4 which is located at the upper part of the exhaust valve body 2 and inserted into the upper part of the exhaust hole 3.
The valve head θa at the lower end is inserted into the exhaust port 3a so as to be openable and closable.

An annular groove θb is provided around the substantially central portion of the exhaust valve 6 in the axial direction.A horizontal hole 7 is formed in the exhaust valve guide 4 symmetrically in the radial direction at a position substantially opposite to the annular groove 6b. ．．
7 is formed.

A spring 9, θ and a steel ball 8, 8 are provided in each horizontal hole 7.7. The spring 9.9 biases the steel ball 8.8, so that the steel ball 8.8 It is removably engaged with the groove 6b. As a result, the exhaust valve 8 is
It is provided so that it can be maintained in the open state shown in the figure. Further, an initial deflection is given to the spring 9.9 by a presser fitting 10110 fixed to the outer end of the lateral hole 7.7 of the exhaust valve guide.

Further, the lower end of the annular groove 6b is formed on the tapered surface 8c.
As a result, a rising force is applied to the exhaust valve 6 by the compressed air, and the steel balls 8.8 move backward against the spring force, making it possible to release the open state of the exhaust valve 6.

Further, in the upper part of the exhaust valve 6 extending upward from the exhaust valve guide 4, by forming the upper part to have a smaller diameter than other parts, stepped parts 6d and 6e are provided with appropriate intervals in the axial direction. An absorber plate 11 is externally mounted on the exhaust valve 6 so as to be slidable in the axial direction between the stepped portions 6d and ee.

The absorber plate 11 is formed in half and fastened with bolts (not shown) to be externally mounted on the exhaust valve 6, and the absorber plate 11 is coaxially fixed to the upper part of the exhaust valve guide 4. The absorber case 12 is movably movable in the axial direction.

The absorb case 12 is the absorb plate 1.
1, and is formed into a substantially downward cup shape with a peripheral wall 12a and a top wall 12b, and when the exhaust valve 6 is closed,
The lower step portion 6e collides with the lower end surface 11a of the absorber plate 11, and the absorber plates 1 and 11 are blown upward as shown in FIG. The stepped portion 6d abuts against the upper end surface 11b of the absorbing plate 11 to prevent the exhaust valve 6 from being pulled out when a downward force is applied to open the valve when taking out the product. Note that when the exhaust valve 6 performs a valve closing operation as shown in FIG. 11 is the top Me1
2b and not the upper step 6d.

Here, the absorbing plate 11 is connected to the exhaust valve 6.
The mounting position is not limited to the upper part of the exhaust valve 6 as shown in the figure, but may be located at an intermediate position or at the end.

Further, a piston 13 formed in half and fastened with bolts (not shown) is fixed to the upper end of the exhaust valve 6, and the piston 13 is attached to the absorber case 1.
The absorber case 12 is slidably fitted into an exhaust spacer 14 coaxially fixed to the absorber case 12.
An air chamber a is provided between the top wall 12b of the exhaust spacer 14 and the piston 13, and an air supply hole 15 is provided in the side wall of the exhaust spacer 14 with an inner end opened in the air chamber a. 15 is connected to one end of a hose 17 via an elbow 18, and the other end of the hose 17 is connected to one air chamber of a detection system valve 22, which will be described later.

As shown in FIG. 3, the gas venting device of the illustrated example
Each exhaust passage 20 is led out from the cavity 19 of 8.
The above-mentioned exhaust system valve 1 and detection system valve 22 are respectively disposed in 21, and during injection molding, the molten metal filling the cavity 19 travels straight through the above-mentioned exhaust path 21 and reaches the detection system valve 22, and is detected by its inertial force. When the valve 23 is closed, a hose is connected to the detection system valve 22 from an air source (not shown) in two air chambers (not shown) which are provided via valve means (not shown) so as to be able to communicate or shut off each other. One air chamber to which air is supplied via 24 communicates with the other air chamber, and air is supplied from the air chamber to the air chamber a of the exhaust system valve 1 via the hose 17. The piston 13 moves up with the exhaust valve 6 due to the pressure, and the valve is closed not directly by the molten metal, but indirectly through the air.Meanwhile, the gas in the cavity 19 flows from the exhaust path 20 to the exhaust hole 3, and then to the exhaust valve. It is configured to pass through the port 30, be sucked by a vacuum pump (not shown), and be discharged to the outside.

Further, one exhaust passage 20 to which the exhaust system valve 1 is attached is provided with an uneven portion so that the exhaust passage 20 is partially narrowed, so that the molten metal arrives with a time delay compared to the other exhaust passage 21. Since it is set in advance, the exhaust port 3
When the molten metal reaches the exhaust port 3a, the exhaust valve 6
Since the valve is already closed, molten metal will not flow into the valve from the exhaust port 3a.

The gas venting device is not limited to the illustrated example, and includes other devices with a known structure in which the exhaust valve is directly closed by the inertia of the molten metal. 13 is not required.

The valve head 6a of the exhaust valve 6 is provided with a tapered surface 6f, so that the tapered surface 6f can be seated airtightly at the exhaust port 3 of the exhaust valve body 2 during the valve closing operation.
A valve seat 3b is formed in a tapered surface.

In the above configuration, when the detection valve 23 of the detection system valve 22 is operated to close due to the inertia of the molten metal during injection molding, the valve means (not shown) of the detection system valve 22 is operated to open the two air chambers. High pressure air is supplied to the air chamber through the hose 17, elbow 16, and air supply hole 15. supplied to a.

As a result, the piston 13 is pushed up, and the exhaust valve 6, which is held in the open position as shown in FIG. The exhaust port 3a is closed by the head 6a, and the exhaust system valve 1 is closed.
At this time, the stepped portion 6e of the exhaust valve 6 is connected to the absorber plate 1.
1 collides with the lower end surface 11a of the absorber brake 1.
The kinetic energy of the exhaust valve 6 will be absorbed by the absorber plate 11.

The absorber plate 11 that has been blown upward hits the top wall 12b of the absorber case 12 and is prevented from moving further upwards, stopping as shown in FIG.

In this way, the kinetic energy of the exhaust valve 6 during the valve closing operation is absorbed by the absorber plate 11, so that the kinetic energy of the exhaust valve 6 is reduced, so that it no longer bounces and the exhaust port 3a is closed by the valve head 6a. is definitely closed.

In addition, both the exhaust valve 6 and the detection valve 23 move the molded product into the mold 1 due to the contraction force when the molten metal solidifies.
7, the valve returns to the open state at the same time and is held at that position by the stopper means.

FIG. 4 is a graph showing measurement data of the bound state of the conventional exhaust valve 6, and FIG. 5 is a graph showing the data of measuring the bound state of the exhaust valve 6 of the present invention.
As is clear from the figure, conventionally, the bounce time takes about the same amount of time as the time it takes for the exhaust valve 6 to close.
The amount of bounce was also 01Bil+, but with the exhaust valve of the present invention, the amount of skin bounce becomes zero at the time of bounce, as shown in FIG. In the above embodiment, the present invention was applied to a valve equipped with a detection valve and an exhaust valve. The present application can be similarly applied to a structure in which an opening/closing mechanism is connected.

〔Effect of the invention〕

According to the structure of the exhaust valve bounce prevention mechanism of the degassing device in the injection molding machine according to the present invention as explained above, during injection molding, after degassing, the exhaust valve 6 is closed due to the inertia of the molten metal or the detection signal. When the valve is closed, the exhaust valve 6 collides with the absorber plate 11 and is blown upward, so that the kinetic energy of the exhaust valve 6 is absorbed by the absorber plate 11 and is reduced, thereby reducing the exhaust gas. Since bouncing of the valve 6 is prevented, the exhaust port 3a of the exhaust valve body 2 can be closed instantly and reliably.
The molten metal will no longer flow into the valve from the exhaust port 3a, thereby eliminating various troubles caused by the molten metal flowing into the valve, and eliminating bounce time.
Since the closing operation time of the exhaust valve 6 is shortened, taking into account that the molten metal advances at a faster rate during injection molding, the effect is significant, as well as improving the yield of products (improving the rate of non-defective products and returning material). Furthermore, since the structure is simple, simply providing a step or the like at a proper location of the exhaust valve 6 and mounting the absorber plate 11 on the outside, it can be manufactured at low cost.

[Brief explanation of the drawing]

1 and 2 are a longitudinal sectional front view in an open state and a longitudinal sectional front view in a closed state, showing an embodiment of an exhaust valve bounce prevention mechanism of a gas venting device in an injection molding machine according to the present invention, respectively; FIG. 3 is a partially sectional front view of an example of a gas venting device equipped with the same embodiment, FIG. 4 is a conventional example, and FIG. 5 is an exhaust valve closing operation in an embodiment of the present invention. This is a graph showing the measurement results of the bounce state at 1.
... Exhaust system valve 3a ... Exhaust port 1 ... Absorb plate 2 ... Absorb case 9 ... Cavity 2 ... Detection system valve 2 ... Exhaust valve body 6 ... Exhaust valve 18 ... Mold 20 ... Exhaust path utility model registration applicant

Claims (1)

[Claims] An exhaust system valve 1 disposed in an exhaust path 20 led from a cavity 19 of a mold 18 is closed by the inertia of the molten metal during injection molding, a detection signal, etc. In this degassing device for an injection molding machine, an absorbing plate 11 is attached to an appropriate position of the exhaust valve, which is slidably attached to the exhaust valve body 2 so that the exhaust port 3a thereof can be opened and closed. Exhaust of a gas venting device in an injection molding machine, characterized in that the absorbing plate 11 is installed so as to collide and move when the valve is operated, and is housed inside an absorbing plate case 12 fixed coaxially with the exhaust valve body. Valve bounce prevention mechanism.