JPH08281409A - Mold degassing device and casting method using mold degassing device - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] When the gas is discharged, the molten metal does not block the gas passage and prevents the occurrence of shrinkage cavities. [Structure] A spiral hot water reservoir 15 is provided on a dividing surface portion in a gas vent passage 14 communicating from the cavity 11 to the outside, and a hole 17 having a diameter smaller than the inner diameter of the hot water reservoir and communicating to the outside is divided at the central portion of the hot water reservoir. A pin 17 having a gas venting groove 18 extending in the axial direction is provided slidably in the hole on the outer peripheral surface after the tip portion at a right angle to the surface portion, and the pool and the gas are retained at the forward and backward limit positions of the pin. A passage 22 which can cut off each of the cutouts is provided between the inner peripheral surface of the tip of the hole and the outer peripheral surface of the pin.
When the pin is moved forward while the molten metal is being filled so that the hot water tank and the gas vent groove communicate with each other to discharge the gas, the centrifugal force in the spiral hot water tank prevents the molten metal from entering the gas vent groove. Immediately before the completion of filling, the pin is retracted to shut off the basin and the degassing groove, and when the molten metal solidifies and contracts, the pin is advanced again to exert a feeder force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold degassing device and a casting method using the mold degassing device. When the mold cavity is filled with molten metal for casting, By extracting a large amount of gas from the mold cavity, filling the mold with molten metal, and then pressurizing the molten metal with a pin, it is possible to create a cast product without gas entrapment and without shrinkage cavities. It was done.

[0002]

2. Description of the Related Art Conventionally, as for a method of extracting gas from a mold, for example, Japanese Patent Publication No. 58-46387,
Japanese Patent Publication No. 59-309, Japanese Patent Publication No. 2-38061 and the like have been put into practical use, but the molten metal that jumps in together with the gas may block the passage of the gas. In addition, to prevent shrinkage cavities, pressure pins are placed near the location of the shrinkage cavities.
The method of pressurizing the melt at the timing of solidification and contraction of the melt is generally used, but in many cases it is not possible to arrange the pressurizing pin at the place where the pressurization is required. For castings that require, it is often difficult to arrange the pressure pin.

[0003]

When the gas is taken out, the molten metal that jumps in together with the gas is prevented from blocking the gas passage, and the molten metal pool is used to pressurize the molten metal with a pin to form a shrinkage cavity around the product. It is intended to prevent the occurrence of.

[0004]

[Means for Solving the Problems] In order to solve these problems, the shape of the pool for extracting gas is made spiral, and a circular hole is formed near the center of the spiral, and a circular groove is formed in this hole. The columnar pins were arranged so that they could come in and out. That is, a spiral hot water reservoir is provided at the mold dividing surface part in the gas vent passage that leads from the mold cavity to the outside of the mold, and a hole that is smaller than the inner diameter of the pool and leads to the outside of the mold at a part of the rear Provided in the mold at the center of the reservoir at a right angle to the mold dividing surface, and on the part of the outer peripheral surface after the tip part, a pin having a gas vent groove extending in the axial direction was slidably provided in the hole. A passage is provided between the inner peripheral surface of the tip of the hole and the outer peripheral surface of the pin at the forward and backward positions of the pin so that the hot water reservoir and the degassing groove can communicate with each other.

When the gas in the mold cavity is to be extracted during the filling of the molten metal, the pin is taken out and the degassing groove provided in the pin is communicated with the swirl chamber so that the gas escapes. The pin is pulled down to block the gas vent groove provided in the pin and the passage of the swirl chamber to prevent the molten metal from entering the gas vent groove side provided in the pin. By pressurizing, part of the molten metal was sent back to prevent the occurrence of shrinkage cavities in the peripheral portion of the product.

[0006]

When the filling of the molten metal into the mold cavity is started with the grooved pin in the center of the spiral pool, the gas extruded by the molten metal fills the groove of the pin. Exhausted through. When the gas expanded by the heat of the molten metal entrains a part of the molten metal and jumps into the pool, the molten metal flows along the wall surface of the spiral pool due to its inertia, and the molten metal flows to the center of the pool. Do not fit.

When the molten metal fills most of the mold cavity, when the grooved pin is retracted, the gas passage is closed, but the amount of remaining gas is small so that it is contained in the pool and the product part It is possible to obtain a cast product without gas entrapment. When a load is applied to the pin to pressurize it in accordance with the state of solidification of the molten metal in the pool, pressure is applied to the semi-solidified melt in the pool. The product is sent back to the peripheral part of the product to supplement the volume of coagulation and shrinkage of the product and prevent shrinkage.

[0008]

1 and 2 show an embodiment of an apparatus for carrying out the method of the present invention. FIG. 1 is a longitudinal sectional view and FIG. 2 is a sectional view taken along line AA of FIG. . Figures 1 and 2 show the structure near the die of the horizontal die clamping horizontal casting die casting machine.
1 is a fixed plate, 2 is a movable plate, 3 is a fixed mold, 4 is a movable mold, 5 is a casting sleeve, 6 is a plunger, 7 is a plunger tip, 8 is a mold dividing surface, and 9 is a mold dividing surface. 8 is a runner part through which the molten metal 10 flows, 11 is a cavity provided on the mold dividing surface 8, 12 is a seal made up of an O-ring mounted near the outer periphery of the mold dividing surface 8 of the fixed mold 3, and the like, 13 is a column.

Cavity 11 of the mold shown in FIGS.
Shows a long one as an example.
In the section, a gas vent passage 14 that finally communicates with the outside of the mold is provided above a part of the cavity 11. At the upper end of the degassing passage 14, a spiral hot water reservoir 15 is provided at the mold dividing surface 8 part.

In the fixed mold 3, a hole 16 having a diameter smaller than the inner diameter of the pool 15 and having a perfect circular cross section communicating with the outside of the mold at a part of the rear is formed in the center of the pool 15. It was installed at a right angle to the section. A cylindrical pin 17 is provided in the hole 16 so as to be slidable in the axial direction, and a tip portion 17a of the pin 17 is provided in the hole 1
It was provided so that it could be put in and taken out from the No. 6.

A plurality of axially extending degassing grooves 18 are provided in a part of the outer peripheral surface at the rear of the tip portion 17a of the pin 17 in the axial direction, or are integrally formed on the entire circumference. . Reference numeral 19 is a gas passage provided in the fixed mold 3 so that a part of the gas vent groove 18 communicates with the outside of the mold, and 20 is a seal such as an O-ring. Reference numeral 21 is a hydraulic cylinder attached to the back surface of the fixed mold 3. The piston rod of the hydraulic cylinder 21 is completely integrated with the pin 17, or the rear end of the pin 17 is connected via a connecting member (not shown). It was connected with the unit.

A passage 22 for communicating the hot water reservoir 15 and the gas vent groove 18 at the forward limit position of the pin 17 and blocking the hot water reservoir 15 and the gas vent groove 18 at the backward limit position of the pin 17 faces the hot water reservoir 15. Inner peripheral surface of the tip of the hole 16 and the tip 17a of the pin 17
It is provided between the outer peripheral surface. In this embodiment, as shown in FIG. 3, the passage 22 is formed in the hole 16 at the inner peripheral surface of the tip of the hole 16.
For example, a hole larger than the inner diameter of 6 by 1 to 3 mm was processed and formed.

Next, the operation of casting using this apparatus will be described with reference to FIGS. The molten metal 10 poured into the casting sleeve 5 of the casting machine is pushed into the cavity 11 by the advance of the plunger tip 7 at the tip of the plunger 6.

At this time, the tip 17a of the pin 17 is projected into the spiral pool 15 by the action of the hydraulic cylinder 21, as shown in FIG. As indicated by the arrow, the gas is discharged to the outside through the passage 22, the gas vent groove 18, and the gas passage 17. At this time, if the gas passage 17 is connected to a vacuum device (not shown), the gas in the cavity 11 can be sufficiently discharged. Further, in that case, in order to prevent air from entering the cavity 11 from the mold dividing surface 8, the seal 12
Need to be attached to the mold dividing surface 8, but since there is no gas outlet on the mold dividing surface 8, the sealing can be completed completely.

When the molten metal 10 is filled in the cavity 11, due to the rapid expansion of the gas caught in the molten metal 10,
The hot water may jump into the hot water reservoir 15, but as shown in FIG. 5, in this spiral hot water reservoir 15, the jumped molten metal 10 is indicated by a thick arrow due to the action of centrifugal force due to inertia. As described above, it does not collide with the outer peripheral wall surface of the swirl chamber and jump into the gas passage 22 which is a small gap on the outer periphery of the pin 17 near the center portion to be blocked.

Immediately before the molten metal 10 fills the cavity 11, as is well known in the art, for example, when a preset time elapses from the start of pouring the molten metal 10 or the flow of the molten metal 10 is stopped. When the pin 17 is pulled down by the operation of the hydraulic cylinder 21 at the time of detection in step 1, the small amount of gas remaining in the cavity 11 is compressed and contained in the pool 15, and the molten metal 10 in the pool 15 is pinned by the pin 17 It does not enter into the gas vent groove 18 or the gas passage 19 by being cooled and solidified in the passage 22 which is a small gap around the. This state
It is shown in FIG.

When the filling is completed and the molten metal 10 starts to solidify, the pin 17 is pushed out by the force of the hydraulic cylinder 21, and the molten metal pool 1
A feeder force is applied to the molten metal 10 in the container 5. This state is shown in FIG. As indicated by the white arrow, when the pin 17 presses the molten metal 10 in the basin 15 with a high surface pressure, the metal is semi-solidified or plastically fluidized to move from the basin 15 to the cavity 11
It flows backward into the cavity 11 and replenishes and compresses the metal in the gap due to the solidification contraction generated in the cavity 11 to prevent the shrinkage cavity. This method is particularly effective for preventing shrinkage cavities in a cast product having a thick portion around the cavity 11.

When the molten metal 10 is completely cooled and the movable mold 4 is opened, the pin 17 is further advanced to project the product 23. This state is shown in FIG. After the product 23 is taken out, as shown by the arrow in FIG. 4B, compressed air is sent back from the gas passage 19 to clean the passage 22 which is the gap between the pins 17 and the spray device 24. The mold release agent 25 is sprayed on the tip portion 17a of the pin 17 or the like to prepare for the next casting.

[0019]

As described above, according to the present invention, a spiral pool is provided at the mold dividing surface portion in the gas vent passage extending from the mold cavity to the outside of the mold. A hole that communicates with the outside of the mold is formed in a part of the mold at the center of the basin at a right angle to the mold dividing surface, and there is a gas vent groove extending in the axial direction on a part of the outer peripheral surface after the tip. A pin is slidably provided in the hole, and a passage is formed between the tip inner peripheral surface of the hole and the tip outer peripheral surface of the pin for communicating and blocking the hot water tank and the gas vent groove at the forward limit position and the backward limit position of the pin. Since the mold degassing device is provided between the molds, the gas in the mold cavity can be sufficiently discharged by the action of the spiral hot water reservoir, and the molten metal does not fly out of the hot water reservoir. Can be Further, by stably discharging the gas in the mold cavity during casting, gas entrapment is eliminated, which enables high-speed casting for thin wall casting with fast cooling.

In addition, when the die venting device is used to advance the pin while the molten metal is being filled so that the hot water reservoir and the degassing groove are communicated with each other, the gas in the die cavity is discharged to the outside of the die. The molten metal is prevented from entering the degassing groove by the action of centrifugal force in the pool, and the pin is retracted just before the completion of the molten metal filling to shut off the pool and the degassing groove. When the molten metal solidified and contracted, the pin was moved forward again to apply the pushing force to the molten metal in the pool for casting, so that the pressurizing effect of the pin caused the occurrence of shrinkage cavities in the thick part around the cast product. By preventing it, it is possible to produce a dense and high-strength cast product of good quality.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a vertical cross-sectional view showing an operation sequence in the device shown in FIG.

FIG. 4 is a vertical cross-sectional view showing the sequence of actions subsequent to FIG.

5 is a cross-sectional view taken along the line BB of FIG.

[Explanation of symbols]

 1 Fixed plate 2 Movable plate 3 Fixed mold 4 Movable mold 5 Casting sleeve 7 Plunger tip 8 Mold dividing surface 10 Molten metal 11 Cavity 12 Slide core 14 Gas vent passage 15 Hot water reservoir 16 Hole 17 Pin 17a Tip 18 Gas Vent groove 19 Gas passage 21 Hydraulic cylinder 22 Passage

Claims (2)

[Claims] 1. A spiral basin is provided at a mold dividing surface portion in a gas vent passage extending from the mold cavity to the outside of the mold,
A hole, which is smaller than the inner diameter of the pool and communicates with the outside of the mold at a part of the rear, is provided in the mold at the center of the pool at a right angle to the mold dividing surface.
A pin having a gas vent groove extending in the axial direction is provided slidably in the hole on a part of the outer peripheral surface after the tip end, and the basin and the gas vent groove are respectively provided at the forward and backward limit positions of the pin. A degassing device for a mold, wherein a passage capable of blocking communication is provided between the inner peripheral surface of the tip portion of the hole and the outer peripheral surface of the tip portion of the pin. 2. A spiral basin is provided at a mold dividing surface portion in a gas vent passage extending from the mold cavity to the outside of the mold,
A hole, which is smaller than the inner diameter of the pool and communicates with the outside of the mold at a part of the rear, is provided in the mold at the center of the pool at a right angle to the mold dividing surface.
A pin having a gas vent groove extending in the axial direction is provided slidably in the hole on a part of the outer peripheral surface after the tip end, and the basin and the gas vent groove are respectively provided at the forward and backward limit positions of the pin. A mold degassing device provided with a passage capable of interrupting communication between the inner peripheral surface of the tip of the hole and the outer peripheral surface of the tip of the pin is used to advance the pin while the molten metal is being filled so that the hot water reservoir and the degassing groove. When the gas in the mold cavity is exhausted to the outside of the mold by communicating with each other, the molten metal is prevented from entering the degassing groove by the action of centrifugal force in the spiral pool, and immediately before the completion of the molten metal filling. Gas for the mold that retracts the pin to block the pool and the degassing groove and moves the pin forward again when the molten metal solidifies and contracts after the completion of filling the molten metal to exert a pushing force on the molten metal in the pool. Casting method using a punching device.