JPH049076Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a gas vent valve device for a casting mold.

(Prior Art) A casting mold generally has a gas vent hole connected to the cavity to vent gas when molten metal is supplied to the cavity. While allowing gas to be discharged from this gas vent hole, it is necessary to prevent the discharge of the molten metal itself, and for this reason, a gas vent valve device is provided for the gas vent hole.

This gas vent valve device is normally open and closes when it receives the pressure of the molten metal, but how accurately the valve closing pressure, or operating pressure, can be set is the key to determining the gas release valve. This is important in preventing molten metal from being discharged from the gas vent hole while effectively venting.

In order to set the operating pressure of such gas vent valve devices to a predetermined value, there are devices that utilize balls and springs. That is, as shown in Japanese Patent Application Laid-Open No. 57-88962, a valve stem that is integrated with a valve body that opens and closes a gas vent hole is slidably inserted into a valve stem guide hole of a housing, and the valve stem and housing are connected to each other. A ball is provided on either side so as to be able to move forward and backward in the radial direction of the valve shaft, and a spring normally positions the ball in an advanced position so as to straddle the valve shaft and the housing. Multiple sets of such balls and springs are provided in the circumferential direction of the valve shaft, and the biasing force of the springs or the advancing position of the balls is adjusted by bolts screwed into the housing. I was trying to do that.
With this configuration, when molten metal pressure that exceeds the locking force of the valve stem against the housing, which is determined by the urging force of the ball or its advancing position, acts on the valve body, the ball retreats and stops engaging the valve stem. The stop action is released and the valve body is closed.

(Problems to be Solved by the Invention) However, in the conventional system using balls and springs, the locking force of each ball on the valve stem is adjusted individually. It is difficult to make each of these locking forces uniform, and the variation in the locking forces makes it difficult to accurately set the operating pressure when the valve is closed to a desired value.

Therefore, an object of the present invention is to provide a gas vent valve device for a casting mold that uses a ball and a spring to set the operating pressure, so that the operating pressure can be accurately set to a desired value. An object of the present invention is to provide a gas vent valve device for a casting mold.

(Means and actions for solving the problems) In order to achieve the above-mentioned object, the present invention has the following configuration. That is, in a gas vent valve device for a casting mold, which is provided for a gas vent hole connected to a cavity of a casting mold and closes the gas vent hole in response to the pressure of molten metal supplied to the cavity, the gas vent valve device opens and closes the gas vent hole. a housing that slidably holds a valve stem integrated with a valve body; and a taper that is formed on the inner surface of a valve stem guide hole of the housing that slides and guides the valve stem, and that widens in the valve closing direction of the valve body. a recess formed on the outer circumferential surface of the valve shaft at a position opposite to the tapered surface and forming a locking shoulder; and a plurality of recesses arranged in the circumferential direction of the valve shaft, each of which is located between the tapered surface and the recess. a ball stored in a storage chamber defined between; an annular pressing plate through which the valve shaft is movable relative to each other and abutting against the plurality of balls; a first spring that biases the plurality of balls toward the valve opening direction of the valve body; a spring force that is weaker than that of the first spring;
A second spring biases the valve shaft toward the valve closing direction of the valve body to bring the locking shoulder into contact with the ball.

With this configuration, the operating pressure, that is, the valve closing pressure, is set by a force corresponding to the spring force of the first spring. The spring force of the first spring is uniformly transmitted to each ball via the annular pressing plate, and each ball is pressed against the outer circumferential surface of the valve stem by the action of the tapered surface, thereby eliminating rattling. This prevents the locking force from being applied by each ball to be uniform. As a result, it becomes possible to reliably close the valve at the desired operating pressure.

(Example) An example of the present invention will be described below based on the attached drawings.

In FIG. 1, a split casting mold 1 consisting of two split molds 1A and 1B has a cavity 2 inside thereof, and from below the cavity 2,
Molten metal is supplied through the passage 3 at a predetermined pressure. Furthermore, the casting mold 1 has a gas vent hole 4 (see also Fig. 2) between the mating surfaces of the two divided molds 1A and 1B, and through this gas vent hole 4, gas is passed during supply of molten metal. Extractions are starting to take place. A gas vent valve device A according to the present invention is provided for this gas vent hole 4.

As shown in FIG. 3, the gas vent valve device A has a housing 12 that is detachably attached to the upper end opening of the gas vent hole 4 relative to the casting mold 1 via a sleeve 11. This housing 12 is constructed by screwing or bolting together a plurality of housing components 12A to 12D, and has a valve chamber B in which the gas vent hole 4 of the casting mold 1 opens in the end portion attached to the casting mold 1. is defined. Further, the gas vent hole 4 formed in the casting mold 1 includes a main passage 4A extending almost vertically upward, and a main passage 4A extending almost vertically upward.
It has two bypass passages (trap passages) 4B that are branched, and each passage 4A, 4B is connected to the valve chamber B.
It is opened to

A valve body 13 is arranged in the valve chamber B, and this valve body 1
A valve shaft 14 extending integrally upward from the valve shaft 3 is fitted into a valve shaft guide hole 15 formed in the housing 12 so as to be slidable in the vertical direction. Further, the housing 12 has a downstream gas vent hole 16 that constitutes a part of the gas vent hole, and this downstream gas vent hole 16
One end thereof opens into the valve chamber B, and the other end thereof opens into the side surface of the housing 12. When the valve body 13 is in the downwardly displaced position shown in FIG. It is in a state where it is in communication with the downstream side gas vent hole 16 (open). Also, the valve body 13
When displaced upward in the figure and seated on the valve seat 17 formed in the housing 12, communication between the valve chamber B and the downstream gas vent hole 16 is cut off (closed).

The vicinity of the upper end of the valve shaft 14 is a small diameter portion 14a, and the outer periphery of the valve shaft 14 in this small diameter portion 14a is a recessed portion 18. In addition, on the inner peripheral surface of the valve shaft guide hole 15 that slides and guides the valve shaft 14,
Corresponding to the recess 18, a tapered surface 19 whose diameter increases upward is formed. A storage chamber 2 defined between the outer surface of the valve shaft 14 and the inner surface of the valve shaft guide hole 15 by this tapered surface 19 and the recess 18
0, a plurality of balls 21 are arranged in the circumferential direction of the valve shaft 14.

A portion above the tapered surface 19 is a valve shaft 14.
The spring chamber 22 has a much larger diameter than the outer diameter of the spring chamber 22, and an annular pressing plate 23 and two first and second springs 24, 25 are disposed in the spring chamber 22. The annular pressing plate 23 is configured such that the valve stem 14 is loosely fitted through the annular pressing plate 23 and comes into contact with the upper surface of each of the balls 21 . Further, both the first and second springs 24 and 25 are coil springs, and are arranged concentrically so as to surround the valve shaft 14, and their lower ends are connected to the pressing plate 2, respectively.
It is arranged so that it is seated. Of the two springs 24 and 25, the first spring 24, which has a strong spring force and is located on the outside, urges the pressing plate 23 downward. Further, the valve stem 14 is urged upward by a second spring 25 located on the inside and having a weak spring force. That is, the upper end of the second spring 24 is seated on a receiving member 26 attached to the upper end of the valve shaft 14. A return pressing rod 27 operated by fluid pressure, a solenoid, or the like is arranged above the receiving member 26 at a predetermined interval.

Next, the operation of the above configuration will be explained.

First, before the casting mold 1 is closed and molten metal is supplied from the passage 3, the gas vent valve device A is opened with the valve body 13, that is, the valve shaft 14 in the downward displacement position, as shown in FIG. state. That is, the first
Each ball 21 is displaced to the lowermost position by a strong spring force by the spring 24 via the pressing plate 23, and is therefore urged upward by the weak second spring 25 to displace the valve shaft 14. The locking shoulder 28 at the lower end of the small diameter portion 14 abuts against the ball 21, thereby restricting its upward displacement.
In this valve open state, the valve body 13 fits into the main passage 4a of the casting mold 1 and closes it, but the bypass passage 4b opens into the valve chamber B from the side of the valve body 13, and The downstream gas vent hole 16 is also opened to the valve chamber B.

When molten metal at a predetermined pressure is supplied into the cavity 2 through the passage 3 from the above-mentioned open state, the cavity 2
The gas inside is discharged through the bypass passage 4b of the casting mold 1, the valve chamber B, and the downstream gas vent hole 16.
Note that this gas discharge is performed by evacuation through the downstream gas vent hole 16.

As the molten metal continues to be supplied into cavity 2,
A portion of the molten metal eventually reaches the lower surface of the valve body 13 from the main passage 4a of the casting mold 1, and presses the valve body 13 upward. The pressing force that presses this valve body upward is
It acts as a force to contract the first spring 24 via the locking shoulder 28 of the valve shaft 14, each ball 21, and the pressing plate 23. When the pressure of this molten metal, that is, the force that presses the valve body 13 upward, exceeds a predetermined value, the valve body 13 is displaced upward together with the valve shaft 14 against the biasing force of the first spring 24, and the valve body 13 is seated on the valve seat 17. This prevents the molten metal from being discharged through the gas vent hole 4.

After the molten metal in the cavity 2 solidifies, the casting mold 1 is opened and the solidified metal adhering to the gas vent hole 4, the lower surface of the valve body 13, etc. is removed. At this time, the gas vent valve device A is returned to the open state shown in FIG. Ru. After this, the operations described above will be repeated.

Here, when the valve is closed by receiving molten metal pressure from the open state shown in FIG. 21 is biased toward the center in the radial direction of the valve shaft 14 so as to be securely seated on the locking shoulder 19 by the action of the tapered surface 21, so that the valve can be accurately closed at the desired operating pressure. will be done.

Although the embodiment has been described above, when the balls 21 are disposed in the circumferential direction of the valve shaft 14 at, for example, four locations at considerably large intervals, at least one of the recessed portion 18 or the tapered surface 19 is arranged in the circumferential direction of the valve shaft 14. By forming the balls 21 at predetermined intervals, movement of the individual balls 21 in the circumferential direction of the valve shaft 14 may be restricted.

(Effects of the invention) As is clear from the above, the invention has the following effects:
In a device that uses a ball and a spring to set the operating pressure when closing the valve,
It becomes possible to reliably close the valve at the desired operating pressure.

[Brief explanation of the drawing]

FIG. 1 is an overall sectional view showing an embodiment of the present invention.
FIG. 2 is a view of the split-type casting mold shown in FIG. 1, viewed from the mating surface side. FIG. 3 is an enlarged sectional view of the main part of FIG. 2. 1...Casting mold, 1A, 1B...Divided mold, 2
... Cavity, 3 ... Passage (for molten metal supply), 4
... Gas vent hole, 4a ... Main passage, 4b ... Bypass passage, 12 ... Housing, 13 ... Valve body, 1
4... Valve stem, 15... Valve stem guide hole, 16... Downstream gas vent hole, 17... Valve seat, 18... Recess, 19
... Tapered surface, 20 ... Storage chamber, 21 ... Ball, 23 ... Pressing plate, 24 ... First spring,
25... Second spring, 28... Locking shoulder.

Claims (1)

[Scope of Claim for Utility Model Registration] In a gas vent valve device for a casting mold, which is provided for a gas vent hole connected to a cavity of a casting mold and closes the gas vent hole in response to the pressure of molten metal supplied to the cavity. , a housing that slidably holds a valve shaft integrated with the valve body that opens and closes the gas vent hole, and a housing that is formed on the inner surface of the valve shaft guide hole of the housing that slides and guides the valve shaft, and that is formed on the inner surface of the valve shaft guide hole of the housing that slides and guides the valve shaft, a tapered surface that expands in the valve closing direction; a recess that is formed on the outer peripheral surface of the valve shaft at a position opposite to the tapered surface and constitutes a shoulder for locking; a plurality of recesses arranged in the circumferential direction of the valve shaft, each of which a ball stored in a storage chamber defined between the tapered surface and the recess; an annular pressing plate through which the valve shaft is movable relative to each other and abuts against the plurality of balls; a first spring that urges the plurality of balls toward the valve opening direction of the valve body via the pressing plate; a spring force that is weaker than that of the first spring;
a second spring that urges the valve stem toward the valve closing direction of the valve body and brings the locking shoulder into contact with the ball; Gas vent valve device.