JPH02241651A - Venting device for forming die - Google Patents

Abstract

PURPOSE:To improve prevention of flowing-out of molten metal at the time of venting by arranging resistant part for giving the resistance to flow of molten metal at pressure receiving surface in a gas venting valve. CONSTITUTION:Gas in cavity 9 is exhausted to outside through constituting passages 11 and 12 in a venting passage. As the resistance part on the pressure receiving surface 22b in the gas venting valve 20, projection and ruggedness, etc., are arranged on the pressure receiving surface 22b. Molten metal pressure acts on the pressure receiving surface 22b in the gas venting valve 20 and the action force overcomes to energized force of springs 25 and lock balls 24 are run onto outer circumference of a shaft part 21 from an annular groove 23. As a part of dynamic pressure acts to the pressure receiving surface 22b between the pressure receiving surface 22b and a core 7 besides the static pressure of the molten metal, at the time of closing the gas venting valve 20, a part of the dynamic pressure besides the static pressure can be utilized as the action force. Therefore, sensibility of the gas venting valve 20 is enhanced and accuracy of closed timing for the valve 20 can be improved. By this method, at the time of gas venting, the prevention of flowing-out of the molten metal can be improved.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a gas venting device for a mold.

(Prior Art) Molding equipment is generally equipped with a gas venting device to prevent casting defects such as gas holes and solidification shrinkage cavities from occurring. The degassing device is suitable for boat fishing.
A gas vent passage is formed in the pair of molds to communicate with the outside from the cavity through the mating surfaces of the pair of molds when the molds are clamped, and a gas vent valve is provided in one of the pair of molds. A pressure receiving surface is provided so as to face the gas vent passage, and the gas vent valve is configured to cut off communication between the gas vent passage and the outside when the pressure receiving surface of the gas vent valve receives molten metal pressure. Recently, from the viewpoint of simplifying the configuration and increasing the freedom in arranging the gas vent valve,
As shown in Japanese Patent Publication No. 59-14299, the pressure receiving surface of the gas vent valve is disposed so as to face the gas vent passage between the mating surfaces so as to be movable from a direction substantially orthogonal to the mating surfaces. is being developed.

(Problems to be Solved by the Invention) However, in the above degassing device, the direction of flow of the molten metal and the direction of displacement of the degassing valve are orthogonal to each other, and the degassing valve is arranged so that the gas venting valve moves on the pressure-receiving surface. Based on the static pressure of the flowing molten metal, it is operated in a direction to cut off communication between the gas vent passage and the outside. For this reason, in this degassing device, only the static pressure of the molten metal can be used to operate the degassing valve, making it impossible to obtain good sensitivity and sufficiently increasing the accuracy of the closing timing of the degassing valve. I can't do it. As a result, there is a possibility that the molten metal may flow out to the outside until the gas vent valve shuts off communication between the gas vent passage and the outside.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a degassing device for a mold that improves prevention of outflow of molten metal during degassing.

(Means and effects for solving the problem) In order to achieve the above object, the present invention provides a mold that is divided into a plurality of parts, and when the mold is clamped, a connection is made between the mating surfaces of the mold from the cavity. A gas venting passage communicating with the outside via the gas venting passage is formed, and one of the split molding molds is provided with a gas venting valve, and a pressure receiving surface of the gas venting valve is connected to the gas A degassing device for a mold, which faces the degassing passage from a direction substantially perpendicular to the mating surface and is configured to block communication between the degassing passage and the outside when the pressure receiving surface receives molten metal pressure. In this configuration, a resistance portion that provides resistance to the flow of the molten metal is provided on a pressure receiving surface of the gas vent valve.

With the above configuration, since a part of the flow of the molten metal is in the form of -a, dynamic pressure is applied to the pressure receiving surface in addition to static pressure between the pressure receiving surface and the mold at -a==i+. Part of the molten metal pressure will be applied. Therefore, when closing the gas vent valve, in addition to the static pressure of the molten metal pressure, part of the dynamic pressure can also be used as an acting force, increasing the sensitivity of the gas vent valve and adjusting the closing timing of the gas vent valve. This means that accuracy can be improved.

As a result, prevention of outflow of molten metal during degassing can be improved.

(Example) Embodiments of the present invention will be described below based on the drawings.

In FIGS. 1 to 4, 1 is a Guicast molding device, and the molding device 1 consists of a movable mold 2 and a fixed mold 3, as shown in FIG. 2, and the movable mold 2 has a plurality of guides. rod 4
It is possible to open and close (approach and move away from) the fixed mold 3 by being guided by.

A core 5 is provided in the movable mold 2, and the end face of the core 5 constitutes a part of the mating surface 6 of the movable mold 2. A core 7 is also provided within the fixed mold 3, and the end face of this core 7 constitutes a part of the mating surface 8 of the fixed mold 3.

The cores 5 and 7 form a cavity 9 and a degassing passage 10 that communicates the cavity 9 with the outside when the movable mold 2 and the fixed mold 3 are clamped. The cavity 9 has a desired product shape, for example, a transmission case shape, and the gas vent passage 10 has a constituting passage 11 formed between the mating surfaces 6.8 as shown in FIG.
The movable mold 2 is formed with a component path 12 that is continuous with the component path 11 and communicates with the outside.

A cylindrical valve guide 13 is fitted and held within the core 5, as shown in FIGS. 2 and 3. The distal end surface (the left end surface in FIG. 3) of this valve guide t3 constitutes a part of the mating surface 6 and is in contact with the core 7, and the rear end of this valve guide (the left end surface in FIG. The right end) faces the through hole 14 formed in the movable mold 2. The inside of the valve guide 13 is a stepped hole, and the inside diameter of the valve guide 13 is divided into a large diameter portion 15, a medium diameter portion 1,
6, a small diameter part 17 and an enlarged diameter part 18, and a valve seat 19 is formed between the large diameter part 15 and the medium diameter part 16.

A gas vent valve 20 is held in the valve guide 13 as shown in FIGS. 2 and 3. The gas vent valve 20 is composed of a shaft portion 21 and a valve portion 22 provided on the tip side (left side in FIG. 3) of the shaft portion 21. The shaft portion 21 is slidably fitted to the small diameter portion 17, and the valve portion 22 is fitted to the large diameter portion 1.
5, and the back portion 22a of the valve portion 22 can move to and from the valve seat 19 as the shaft portion 21 slides. An annular groove 2 is provided on the outer periphery of the shaft portion 21.
3 is formed. This annular groove 23 and the valve guide 1
A lock ball 24 is disposed between the shaft portion 3 and the shaft portion 21, and the lock ball 24 is urged inward in the radial direction of the shaft portion 21 by a spring 25. Therefore, the urging force of the spring 25 is overcome and the lock ball 24 is moved from the annular groove 23 to the shaft portion 21.
The lock ball 24 will not fit into the annular groove 2 unless a force sufficient to put it on the outer periphery is applied to the shaft portion 21 in the axial direction of the shaft portion 21.
It is designed to fall within 3.

A piston 27 is fitted and held on the outer periphery of the rear end side (right end side in FIG. 3) of the shaft portion 21. The piston 27 is slidably fitted into the enlarged diameter portion I8 of the valve guide 13, and a spring 28 is interposed between the piston 27 and the valve guide I3.
7 is biased in the direction in which the back portion 22a of the valve portion 22 is seated on the valve seat 19. However, in this case, the biasing force of the spring 28 is such that the lock ball 24
Therefore, the lock ball 24 is defined by the circumferential wall of the annular groove 23, and the valve part 22 is separated from the valve seat 19. (See Figure 3).

The valve portion 22 of the degassing valve 20 has a pressure receiving surface (tip surface) 22b that contacts the core 7 as the shaft portion 21 slides.
The pressure receiving surface 22b is in contact with and separated from the pressure receiving surface 22b.
is adapted to come into contact with the core 7 when the back portion 22a is spaced apart from the valve seat 19 (see FIG. 3). As shown in FIG. 4, an annular groove 60, an inflow groove 61, and outflow grooves 62a and 62b are formed in this pressure receiving surface 22b. The annular groove 60 is provided on the radially inward side of the pressure receiving surface 22b so that its axis coincides with the axis of the shaft portion 21, and the groove width of the annular groove 60 is made relatively narrow. There is. The inflow groove 61 is formed between the annular groove 60 and the outer peripheral edge of the pressure receiving surface 22b on the lower end side of the pressure receiving surface 22b, and the groove width of the inflow groove 61 is twice the groove width of the annular groove 60. It is set widely. The outflow groove 62 is formed between the annular groove 60 and the outer peripheral edge of the pressure receiving surface 22b on the upper end side of the pressure receiving surface 22b, and the groove width of the outflow groove 62 is made equal to the groove width of the annular groove 60. It is narrower than the inlet groove 61. Two outlet grooves 62 are provided in this embodiment, and both outlet grooves 62a and 62b are arranged symmetrically with respect to the vertical direction. In this case, the groove depths of the valley grooves 60 to 62 are substantially constant.As a result, the inflow groove, the annular groove 60, and the outflow groove 62 form a constricted portion as a resistance portion. There is.

The shaft portion 21 of the gas vent valve 20 and the valve guide 13
An annular space 29 is formed between the inner diameter portion 16 and the inner diameter portion 16, as shown in FIG. A vacuum pipe 30 faces this annular space 29, and gas, etc. in the stratified space 29 is discharged to the outside via the vacuum pipe 30 under vacuum.

The valve guide 13 has a plurality of cutout grooves 63, 64, 65 in the large diameter portion 15, as shown in FIGS. 3 and 4.
a and 65b are formed. The notch groove 63 is formed so as to extend downward continuously from the inflow groove 61,
The notch groove 63 is connected to the outer peripheral side of the pulp guide 13 and the inflow groove 61.
It communicates with The notch groove 64 is the gas vent valve 20
The notch 64 is formed above the valve portion 22 and closer to the tip of the valve guide 13 than the valve seat 19, and the notch 64 communicates the annular space 29 with the outer peripheral side of the pulp guide 13. The notch grooves 65a and 65b are provided so as to be continuous with the outflow groove, respectively, and each of the notch grooves 65a,
65b communicates the outflow grooves 62a and 62b with the outer peripheral side of the pulp guide 13.

As shown in FIGS. 3 and 4, an annular core 32 is fitted and held in the valve guide 13 on the outer peripheral side of the notched grooves 63, 64, 65a, 65b. This annular core 32 is also fixed to the core 5, and the end face of the annular core 32 forms part of the mating surface 6 together with the end face of the valve guide 13. Arc grooves 66a, 66b, vertical grooves 67a, 67b, introduction grooves 68a, 68b, and communication grooves 69a, 69b are formed on the end face of this annular core 32. The arcuate groove 66a is formed below the valve guide 13 so as to form a concentric arc with respect to the valve guide 13, and the vertical groove 67a is formed so as to communicate the arcuate groove 66a with the notch groove 63. It is formed. The introduction grooves 68a and 68b are formed so as to communicate the arcuate groove 66a with the outer peripheral side of the annular core 32, respectively. It communicates with the cavity 9 via 70b. The arcuate groove 66b is formed above the valve guide 13 so as to form a concentric arc with respect to the valve guide 13, and the vertical groove 67b is formed to communicate the arcuate groove 66b with the notch groove 64. Grooves 69a, 69
b is formed so as to communicate the arcuate groove 66b with the notch grooves 65a and 65b, respectively. As a result, the grooves 70a, 70b, the introduction grooves 68a, 68b, the arcuate groove 6
6a, vertical groove 67a, notch groove 63, inflow groove 61. Annular groove 60, outflow grooves 62a, 62b notch grooves 65a, 65b,
The communication grooves 69a and 69b constitute the constituting passage 11 of the gas venting passage 102, and the circular arc groove 66b, the vertical groove 67b, the notched groove 69b, and the annular space 29 constitute the constituting passage 12 of the degassing passage 10.
It consists of

The movable mold 2 is provided with an ejector box 41 as shown in FIG. This ejector box 4
1, an ejector plate 42 operated by a drive cylinder (not shown) is disposed, and the ejector plate 42 has a longitudinal groove 67b at its tip and a plurality of ejector bins facing the component path 11, etc. 43 is attached and a push rod 44 is held. The push rod 44 is slidably held by the ejector plate 42, and one end thereof is connected to the push portion 4.
6 is inserted into the through hole 14, and a nut 47 is attached to the other end on the outer side of the ejector plate 42. A spring 48 having a stronger spring force than the spring 28 is inserted into the outer periphery of the push rod 44, and the push portion 46 of the push rod 44 is pushed in the direction away from the ejector plate 42 by the spring 48. Forced.

Such a push rod 44 is adapted to press the gas vent valve 20 when taking out the product, thereby giving the gas vent valve 20 the function of pushing out the product in the same way as the ejector bin 43 described above.

In FIG. 2, 49 indicates a molten metal inlet, and in FIG. 3, 50 indicates an air supply pipe.

Therefore, in the above device, when the molten metal is pressurized and injected into the cavity 9 from the molten metal inlet 49 by the pouring plunger, the gas in the cavity 9 passes through the constituent passages 11 and 12 in the degassing passage. and is released to the outside as shown by the arrow in FIG. Next, the molten metal pressure acts on the pressure receiving surface 22b of the gas vent valve 20, and the acting force overcomes the biasing force of the spring 25, causing the lock ball 24 to ride from the annular groove 23 onto the outer periphery of the shaft portion 21. Therefore, in the gas vent valve 20, the valve portion 22 immediately seats on the valve seat 19 based on the biasing force of the spring 28, and the gas vent passage IO is cut off from the outside, and the molten metal in the cavity 9 is kept in a predetermined pressurized state. to be cast.

In this case, since the groove widths of the annular groove 60 and the outflow groove 62 are narrowed down to form a resistance part compared to the groove width of the inflow groove 61, part of the flow of the molten metal is caused by the resistance of the resistance part. ,
Pressure receiving surface 22b of gas vent valve 20 and core 7 with low resistance
(fixed mold 3) (especially toward the core 7 side), and since the molten metal is an incompressible fluid,
Between the pressure receiving surface 22b and the core 7, a part of the dynamic pressure acts on the pressure receiving surface 22b in addition to the static pressure of the molten metal. Therefore, when the gas vent valve 20 is closed, a part of the dynamic pressure can be used as an acting force in addition to the static pressure, so the sensitivity of the gas vent valve 20 can be increased, and the gas vent valve 20
This means that the accuracy of the zero closing timing can be improved. Thereby, it is possible to improve prevention of outflow of molten metal during degassing.

Although the embodiments have been described above, the present invention includes the following.

(2) When the valve portion 22 is spaced apart from the valve seat 19, the pressure receiving surface 22b is spaced apart from the fixed mold 3 by a predetermined distance.

(2) Protrusions, irregularities, etc. are provided on the pressure receiving surface 22b as a resistance portion on the pressure receiving surface 22b.

■For example, when this device is placed on the side of the movable mold 2, a gas vent passage is formed at the joint between the core 5 and the slide core (located at the position of the fixed mold 3 in Fig. 3), and the gas Applicable to molding equipment equipped with a extraction valve.

(Effects of the Invention) As described above, the present invention can provide a degassing device for a mold that improves prevention of outflow of molten metal during degassing.

[Brief explanation of drawings]

FIG. 1 is a front view showing a movable mold according to an embodiment of the present invention; Figure 2 is a sectional view taken along line A-A in Figure 1; FIG. 3 is an enlarged sectional view of main parts showing an embodiment of the present invention. FIG. 4 is a sectional view taken along the line B--B in FIG. 3. 6, 8 1. 2b 0a 62a, 62b : Movable type :Fixed type :Mating face :cavity : Gas vent passage : Constituent path : Gas vent valve :Pressure receiving surface : Annular groove :Inflow groove Double outlet groove Figure 1 Figure 2

Claims (1)

[Claims] (1) A gas vent passage is formed in a plurality of divided molds to communicate with the outside from the cavity through between the mating surfaces of the divided molds when the mold is clamped, and one of the divided molds is The mold is provided with a degassing valve, and the degassing valve has a pressure receiving surface facing the degassing passage from a direction substantially perpendicular to the mating surface, and the pressure receiving surface absorbs molten metal pressure. In the degassing device for a mold, the degassing device is configured to cut off communication between the degassing passage and the outside when the degassing valve receives a pressure, and a resistance part that provides resistance to the flow of the molten metal is provided on the pressure receiving surface of the degassing valve. A gas venting device for a mold, which is characterized by: