JP3176511B2 - Casting mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold used for gravity casting, and more particularly, to a main runner extending downward from a sprue between a pair of first and second mold surfaces joined to be openable and closable. The present invention relates to an improvement of a sub-runner extending laterally from a main runner and a mold having a cavity connected to a tip of the sub-runner.

[0002]

2. Description of the Related Art Conventionally, in such a mold, an air bleeding passage connected to the outside is connected to a sub-runner connecting a main runner extending downward from a gate and a cavity, and gas in the molten metal flowing through the sub-runner is released to a gas bleeding passage. There has been known a method in which a high quality casting without burrows is obtained (see, for example, Japanese Patent Publication No. 61-34899).

[0003]

However, in the above-mentioned conventional mold, it is necessary to perform cleaning to remove burrs clogged in the gas vent passage every time the mold is opened after casting, and the operation is troublesome. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a mold capable of automatically removing burrs clogging a gas vent passage when releasing a casting after casting. The purpose is to do.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a main runner extending downward from a sprue between a pair of first and second mold surfaces which are openably and closably joined. A sub-runner extending laterally from the main runner,
And in the mold forming a cavity continuous with the distal end of the sub-runners, the junction surfaces of the first and second type, the release passage to permit passage of molten metal extending upward from an intermediate portion of the sub-runners, the relief passage An expansion chamber connected to the upper end is further formed, and a pin hole extending in a direction perpendicular to the joining surface of the two molds and opening to the expansion chamber is formed in one of the two molds. When both molds are opened, a degassing passage that allows the passage of only gas is defined between the push pins protruding into the expansion chamber when both molds are opened.
The extrusion pin protruding allows release of the entire casting
The first, characterized in that the the.

In addition, the present invention has a second feature in that, in addition to the above features, a filter chamber for accommodating a filter is formed in an intermediate portion of the sub-runner, and an escape passage extends from the filter chamber.

According to the present invention, in addition to the first or second feature, a recess is provided above the sub-runner downstream of the escape passage, and the recess is communicated with the expansion chamber via the second escape passage. This is a third feature.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

First, a first embodiment of the present invention shown in FIGS. 1 and 2 will be described. A metal mold for gravity casting, that is, a mold 1, includes a fixed mold 2 (first mold) and a movable mold 3 (second mold) joined to the fixed mold 2 so as to be openable and closable.
Both types 2 and 3 are arranged with the joining surface vertical.
A main runner 4 having an open upper end and extending in the vertical direction, a plurality of sub-runners 5 branching from the lower end of the main runner 4 and extending linearly in the horizontal direction, are provided between the joining surfaces. A cavity 7 connected to the tip of the main runner 6 and extending upward is formed, and both halves of a split gate block 8 having a gate 8a connected to the open end of the main runner 4 are fixed and movable molds 2, 3. Are respectively attached to the upper surfaces of the.

A filter chamber 9 for accommodating a filter F made of ceramic is formed at an intermediate portion of the sub-runner 5, and an expansion chamber 11 is formed at an upper end of a relief passage 10 extending upward from the filter chamber 9 and allowing the passage of molten metal. Are continuously installed. Movable type 3
A pin hole 12 extending in a direction perpendicular to the joint surface of the fixed die 2 and the opening and opening the expansion chamber 11, and supported by a support plate 13 fixedly installed behind the movable die 3. The push pin 14 is slidably inserted into the pin hole 12. Between the outer peripheral surface of the push pin 14 and the inner peripheral surface of the pin hole 12, a cylindrical gas vent passage 15 for communicating the expansion chamber 11 with the outer end is defined. The thickness of the gas vent passage 15 is suitably about 0.1 to 0.3 mm in order to minimize the intrusion of the molten metal and obtain the desired gas venting effect.

When the two dies 2 and 3 are closed, the support plate 13 is closed.
Is arranged at a fixed distance from the movable mold 3. At this time, the tip of the push pin 14 is substantially flush with the inner surface of the expansion chamber 11.

Next, the operation of this embodiment will be described.

At the time of casting, first, the movable mold 3 is
And then poured into the gate 8a. Then, the molten metal flows down the main runner 4 to form a plurality of sub-runners 5.
When passing through the filter chamber 9, it is filtered by the filter F, and foreign matter containing gas is captured. And weir 6
Thus, the cavity 17 is gently filled from below to above.

On the other hand, the gas trapped in the filter chamber 9 rises along the escape passage 10 together with a part of the molten metal and moves to the expansion chamber 11. Then, the gas is discharged to the outside through the gas vent passage 15. However, since the gas vent passage 15 is so narrow in cross-section that the molten metal cannot pass through, the molten metal that has risen to the expansion chamber 11 is discharged to the gas vent passage 15. 15 only slightly penetrates and fills the chamber 11.

Thus, the cavity 7 can be filled with a high-quality gas-free molten metal, which contributes to the casting of a high-quality product having no pits.

Next, after the molten metal solidification time in the cavity 7 elapses, the movable mold 3 is opened, and burrs penetrate into the gas vent passage 15, so that the casting adheres to the movable mold 3 side. With the opening of the movable mold 3, the support plate 13 is relatively moved.
Comes closer to the movable mold 3 , so that the pushing pin 14
Protrudes into the expansion chamber 11 and releases the casting adhered to the movable mold 3. At this time, the burrs that have cut into the gas vent passage 15 are also released at the same time, so that the gas vent passage 15
There is no need to clean up later.

In the casting thus taken out, the neck formed by the weir 6 is broken to separate the product part from the scrap part.

FIG. 3 shows a second embodiment of the present invention.
A recess 16 is formed in the upper part of the inner surface of the sub-runner 5 downstream from the filter chamber 9, and the recess 16 is formed in the second escape passage 17.
The structure is the same as that of the previous embodiment except that it is communicated with the expansion chamber 11 through the, and in the figure, the parts corresponding to the previous embodiment are denoted by the same reference numerals.

According to this embodiment, at the time of pouring, even if gas remains in the molten metal that has passed through the filter chamber 9, the gas floats on the recessed portion 16 and, together with a part of the molten metal, the second escape. After passing through the passage 17 to the expansion chamber 11 and then flowing out to the gas vent passage 15 as described above, the gas venting property is further improved, which can contribute to the improvement of quality.

In each of the above embodiments, various design changes can be made without departing from the spirit of the present invention. For example, in addition to the extrusion pin 14 projecting into the expansion chamber 11, an extrusion pin projecting into the cavity 7 can be added. However, as in the above embodiments, the expansion chamber 11
Since the release of the entire casting can be performed only by the extrusion pin 14 of the above, since there is no trace of the extrusion pin in the product part,
preferable.

[0021]

As described above, according to the first feature of the present invention, an escape passage extending upward from the intermediate portion of the sub-runner and allowing the molten metal to pass between the first and second mold joining surfaces. When,
An expansion chamber connected to the upper end of the escape passage is formed, and a pin hole extending in a direction orthogonal to the joint surface of both molds and opening to the expansion chamber is formed in one of the molds. When the two molds are opened by being inserted into the pin holes, a degassing passage that allows only gas to pass is defined between the extrusion pin and the extrusion pin that protrudes into the expansion chamber. As a result, it is possible to obtain a high-quality casting without burrows, and it is possible to remove burrs clogged in the gas vent passage at the same time as the mold is released by the extrusion pin, thereby eliminating troublesome cleaning of the gas vent passage. be able to. Opening of both types
Extrusion pins projecting into the expansion chamber when released release the entire casting.
Release is possible, so traces of the above-mentioned extrusion pins are formed on the product part.
Never leave.

According to the second feature of the present invention, a filter chamber for accommodating a filter is formed in an intermediate portion of the sub-runner, and an escape passage extends from the filter chamber. And the degassing property can be further improved, and a higher quality casting can be obtained.

Further, according to the third aspect of the present invention, a recess is provided above the sub-runner downstream of the relief passage, and the recess is communicated with the expansion chamber via the second relief passage. Since degassing is performed in two stages from the molten metal flowing through the sub-runner, the quality of the casting can be further improved.

[Brief description of the drawings]

FIG. 1 is an inner view of a mold according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is an inner view of a mold according to a second embodiment of the present invention.

[Explanation of symbols]

 F Filter 1 Mold 2 Fixed mold (first mold) 3 Movable mold (second mold) 4 Main runner 5 Subrunner 7 Cavity 8a Gate 9 Filter chamber 10 Escape passage 11 Expansion chamber 12 Pin hole 14 Extrusion pin 15 Gas vent passage 16 Concave Entrance 17 Second escape passage

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Kofuna 1-10-10, Shinsayama, Sayama-shi, Saitama Honda Motor Co., Ltd. Saitama Works (56) References JP-A-6-91343 (JP, A) Japanese Utility Model Application Sho 58-47360 (JP, U) Japanese Utility Model Application Hei 4-94145 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22C 9/06 B22C 9/00 B22C 9/08

Claims (3)

(57) [Claims] A main runner (4) extending downward from a sprue (8a) between a pair of first and second molds (2, 3) joined to be openable and closable. In the mold in which the sub-runner (5) extending in the lateral direction and the cavity (7) connected to the tip of the sub-runner (5) are formed, the sub-runner (5) is provided between the joining surfaces of the first and second molds (2, 3). A relief passage (10) extending upward from the middle part of (5) and allowing the molten metal to pass therethrough, and an expansion chamber (11) connected to the upper end of the relief passage (10) are further formed. ), A pin hole (12) extending in a direction perpendicular to the joining surface and opening to the expansion chamber (11) is formed in one of the two molds (2, 3). It is inserted into the pin hole (12) and projects into the expansion chamber (11) when both dies (2, 3) are opened. A degassing passageway (15) allowing only gas to pass therethrough is defined between the extrusion pin (14) and both molds (2, 2).
When the opening of 3), the extrusion pin which projects into the expansion chamber (11) is used.
A mold characterized in that the whole casting can be released from the mold by means of a mold (14) . 2. A filter chamber (9) for accommodating a filter (F) in an intermediate portion of a sub-runner (5), and a relief passage (10) from the filter chamber (9). Wherein the mold is extended. 3. The recess according to claim 1, wherein a recess (16) is provided above the sub-runner (5) downstream of the relief passage (10), and the recess (16) is connected to the second relief passage. A mold characterized in that the mold is communicated with the expansion chamber (11) through (17).