JPH07299544A - Core release device - Google Patents

Abstract

(57) [Summary] [Purpose] By increasing the mounting rigidity of the degassing pin, it is possible to prevent the gassing pin from being caught in the extrusion pin due to bending, improve the degassing performance by extending the degassing pin, and manufacture parts. (EN) Provided is a mold releasing device for a core, which is easy to perform and can prevent wear of a mold due to an extrusion pin. [Structure] A device for removing a core by attaching it to a mold 24 for core molding, wherein a hollow guide part 29 through which an extrusion pin that reciprocates during mold release is inserted, and a cavity of the mold 24. A core releasing device comprising a gas releasing pin (22) which is integrally formed with a pin portion (30) projecting inward and forming a gas releasing hole in the core, and the extruding pin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold releasing device for a core used in a casting core mold for molding a gas vent hole in the core.

[0002]

2. Description of the Related Art A conventional core mold releasing device is shown in FIG.
There is something like that shown in FIG. This is because the mold 2 for molding the core 1 is horizontal to the upper mold 2a having the sand blowing port 3 and the lower mold 2b having the opening 5 formed to match the outer diameter of the extrusion pin 4. It is divided, and the gas vent pin 7 is pressed against the lower mold 2b by the pressing plate 6, and the bolt 9 inserted into the bolt hole 8 of the pressing plate 6 is fastened to fix the gas vent pin 7 to the lower mold 2b. I am trying. At the time of releasing the mold, the core 1 having the gas vent hole 10 formed in the portion corresponding to the gas vent pin 7 is released from the mold 2 by moving the push pin 4 upward.

As another conventional mold releasing device for a core, a device proposed in Japanese Utility Model Publication No. 1-20044 is known. This is because the eject plate provided with the eject pin facing the cavity of the mold on the back side of the mounting plate of the core molding die is arranged so that it can be moved in and out of contact with the mold. Forming a vertical hole that extends vertically through the upper half and opens at the upper end, and a cutout groove that extends in the longitudinal direction of the lower half that communicates with the vertical hole at the middle of the eject pin On the plate,
A substantially L-shaped gas vent pin that is inserted into the vertical hole from the end of the cutout groove is attached.

As shown in FIG. 11, the degassing pin 11 is sandwiched between two pressing plates 12 and 13 from above and below and is fastened to a mounting plate of a mold by a bolt 14. When the gas vent pin 11 and the pressing plate 12 are manufactured, the procedure is as follows. That is, as shown in FIG. 12 (a), the unnecessary portion 15a is cut from the material 15 with a milling machine, and the L-shaped member 16 which is the required portion is cut out.
As shown in FIG. 12 (b), the needle-shaped portion 16a of the L-shaped member 16 is tapered by a cutting tool 17 of a lathe. Then Figure 12
As shown in (c), the root part 16b of the needle-shaped part 16a is rounded with an NC machine tool to manufacture the degassing pin 11.

On the other hand, as for the pressing plate 12, as shown in FIG. 13 (a), the unnecessary portion 18a is cut from the material 18 with a milling machine, and the spatula-like member 19 which is the necessary portion is cut out, and then, the
As shown in (b), a groove 20 is formed at the center of the spatula-shaped member 19 by a milling machine or an end mill. And Fig. 13
As shown in (c), a boring machine or a milling machine is used to drill the bolt holes 21 to manufacture the pressing plate 12.
The other pressing plate 13 is also manufactured by a method according to this.

[0006]

In any of the above-mentioned conventional examples, the pressing plate 6 (12, 13) and the gas vent pin 7 (11) have a divided structure, and the insertion portion into the mold 2 is small. Since the extrusion pin (eject pin) 4 moves up and down each time the core is molded, there is a problem that the bolt 9 (14) is easily loosened and the degassing pin 7 (11) is easily rattled.

[0007] And, if it is operated without noticing,
There is a problem that the gas vent pin 7 (11) is bent and meshes with the push pin 4. In addition, the gas vent pin 7 (1
Since 1) cannot be made sufficiently long, there is a problem that the gas of the core 1 cannot be sufficiently escaped during pouring, which causes a gas defect. Further, as shown in FIGS. 12 and 13, many steps are required to manufacture the gas vent pin 11 and the pressing plates 12 and 13, which is difficult to manufacture. Furthermore, core 1
There is a problem in that the die 2 that rubs against the extruding pin 4 is abraded by the extruding pin 4 that moves up and down each time the die is released.

In view of the above problems, the present invention prevents the biting pin from being caught in the extrusion pin due to the bending of the gas releasing pin by improving the mounting rigidity of the gas releasing pin (improving the operation rate), and by extending the gas releasing pin. It is an object of the present invention to provide a core releasing device that improves the degassing performance (prevents gas defects), can easily manufacture parts, and can prevent the die from wearing due to the extrusion pin.

[0009]

A mold releasing apparatus for a core according to the present invention for achieving the above object is a device for removing a core by attaching it to a mold for molding a core. A hollow guide part through which an extruding pin that reciprocates when a mold is inserted, and a gas releasing pin integrally formed with a pin part that projects into a cavity of the mold and forms a gas releasing hole in a core, and the extruding pin, It consists of

When the mold releasing device for the core is attached to a mold, the gas vent pin has a bolt hole,
It is possible to use means such as providing a flange portion that is positioned on the mold and fastening bolts. In that case, it is preferable to form a bolt groove in which the head portion of the bolt is buried and communicates with the bolt hole in the flange portion. Further, the guide portion for guiding the movement of the extrusion pin may be configured by a cylindrical outer shell portion, a root portion of the pin portion, and a bridge portion connecting the outer shell portion and the root portion. it can.

[0011]

[Operation] The core mold releasing device according to the present invention has the above-mentioned configuration, and since the guide portion through which the extrusion pin is inserted and the pin portion for forming the gas vent hole are integrally formed, The mounting rigidity of the gas vent pin can be kept high. Therefore, the length of the pin portion of the gas vent pin can be made longer than before, so that the gas in the core can be surely released during pouring, and the occurrence of gas defects can be prevented.

Further, since it is integrally molded, the number of parts can be minimized, and it can be easily manufactured in an extremely small number of steps, and the work of attaching it to the mold can be significantly facilitated. Furthermore, since the guide portion eliminates the sliding of the reciprocating extrusion pin each time the core is released from the mold, abrasion of the mold can be prevented and the durability of the mold can be improved. It can be greatly improved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the present invention will be described with reference to FIGS. First, the mold release device for the core of the present embodiment is composed of a gas vent pin 22 and an extruding pin (not shown), and the circular flange portion 23 of the gas vent pin 22 has a metal mold.
A bolt hole 27 into which a bolt 26 to be screwed into a screw portion 25 formed in 24 is inserted, and a bolt formed to a depth such that the head 26a of the bolt 26 is buried when the bolt 26 is completely fastened. The groove 28 and the groove 28 are continuously formed, and are arranged so that the bolt groove 28 is located outside the mold 24.

The guide portion 29, which is formed hollow to allow the push-out pin to be inserted, comprises a cylindrical outer portion 29a, a root portion 29b of the pin portion 30, and a bridging portion 29c for connecting them,
It has a shape in which a C-shaped cavity 31 is formed. The pin portion 30 is gradually tapered from the root portion 29b toward the tip, and the tip is rounded. On the other hand, the mold 24 to which this is attached is formed with a positioning hole 32 into which the guide portion 29 is fitted and a step portion 33.
A back slope 34 is formed at the back of 33.

When manufacturing this gas vent pin 22,
First, as shown in FIG. 5, an unnecessary portion 35a is cut from a carbon steel round bar material 35 by a lathe tool 36, and a flange portion 23 having the largest diameter, a guide portion 29 having a smaller diameter than that, and a smaller diameter portion. 3 and the needle-shaped pin portion 30 with a draft
Make a step shape. Next, as shown in FIGS. 6A and 6B, a drilling machine is used to form bolt holes 27 in the flange portion 23 and small-diameter holes 37 in the guide portion 29.
Then, as shown in FIGS. 7 (a) and 7 (b), the small-diameter hole
Pass the wire of the wire cut electric discharge machine to 37 and cross-section C
It is processed so as to form a V-shaped cavity 31. The flange portion 23 has a bolt groove 28 for accommodating the head 26a of the bolt 26.
Is processed with an end mill. In addition, the extruding pin (not shown) has a minute gap (approximately 0.3 mm) between the inner surface of the guide portion 29 and the shape of the hollow guide portion 29.
It has a C-shaped cross-section so that it can slide, and it is a through type.

According to the mold releasing apparatus for the core of the present embodiment, the guide portion 29 is fixed in the positioning hole 32 of the die 24 in a state of being firmly inserted, and the pin portion 30 is integrated with the guide portion 29. Since the support rigidity is extremely high, the pin part
Even if the length of 30 is lengthened, the problem of rigidity does not occur. As a result, since the length of the pin portion 30 can be increased, it is possible to form a deep vent hole in the core to the extent that the gas of the core can be surely released during pouring. Since deformation and collapse can be prevented, the generation of defective products due to gas defects can be significantly reduced.

Further, as described above, since the gas venting pin 22 formed by cutting out from the round rod-shaped material 35 and integrally formed is combined with the extruding pin having the C-shaped cross section, the number of parts is minimized. It can be kept to the limit and can be easily manufactured with extremely few processing steps. Furthermore,
Inserting into the mold 24 and bolts 26
Since it is only concluded, it can be done extremely easily,
Loosening of the bolt 26 is also unlikely to occur.

In addition, since the push pin slides back and forth on the inner surface of the guide portion 29 of the through-hole type gas vent pin 22, sliding between the push pin and the die 24 is eliminated, and the die 24 Wear can be prevented and the durability of the mold can be improved.

[0019]

The core releasing device of the present invention is a device for releasing a core by attaching it to a mold for molding a core, and is a hollow through which an extrusion pin that reciprocates at the time of releasing is inserted. Since the guide part and the extruding pin integrally formed with the pin part projecting into the cavity of the mold and forming the gas releasing hole in the core, and the extruding pin, the mounting rigidity of the gas releasing pin is improved. Can be held high. Therefore, since the length of the gas vent pin can be made longer than in the conventional case, the gas in the core can be surely released during pouring, and the occurrence of gas defects can be prevented.

Further, since it is integrally molded, the number of parts can be minimized, and it can be easily manufactured in an extremely small number of steps, and the work of attaching it to the mold can be significantly facilitated. Furthermore, since the guide portion eliminates the sliding of the reciprocating extrusion pin each time the core is released from the mold, abrasion of the mold can be prevented and the durability of the mold can be improved. It can be greatly improved.

[Brief description of drawings]

FIG. 1 is a plan view of a gas vent pin that constitutes a mold release device for a core according to an embodiment of the present invention.

FIG. 2 is a front view of the gas vent pin of FIG.

3 is a bottom view of the gas vent pin of FIG. 1. FIG.

FIG. 4 is a vertical cross-sectional view of the gas vent pin of FIG. 1 mounted on a mold.

FIG. 5 is a front view of the gas vent pin of FIG. 1 in a manufacturing process.

6A is a front view in the process of manufacturing the gas vent pin of FIG. 1, and FIG. 6B is a side view of the same.

7A is a front view in the process of manufacturing the gas vent pin of FIG. 1, and FIG. 7B is a side view of the same.

FIG. 8 is a front view of a conventional core molding apparatus.

9 is a vertical cross-sectional view of a mold releasing apparatus used in the molding apparatus of FIG. 8 in which a gas vent pin is attached to a mold.

10 is a bottom view of the degassing pin of FIG. 9. FIG.

FIG. 11 is a perspective view of a degassing pin and a pressure plate of another mold releasing device used in the conventional core molding device.

12A and 12B show a manufacturing process of the gas vent pin of FIG. 11, where FIG. 12A is a front view of a first step, FIG. 12B is a front view of a second step, and FIG. 12C is a front view of a third step. FIG.

13A and 13B show a manufacturing process of the one pressing plate of FIG. 11, where FIG. 13A is a front view of a first step, FIG. 13B is a front view and a side view of a second step, and FIG. It is a front view of a process.

[Explanation of symbols]

22 Gas vent pin 23 Flange part 24 Mold 26 Bolt 26a Head part 27 Bolt hole 28 Bolt groove 29 Guide part 29a Outer part 29b Root part 29c Bridge part 30 Pin part

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Kenji Sakai 58, Kuze-Denjo-machi, Minami-ku, Kyoto-shi, Kyoto Prefecture Sakao Machinery Co., Ltd.

Claims (4)

[Claims] 1. A device for detaching a core by attaching it to a mold for core molding, wherein a hollow guide part through which an extrusion pin that reciprocates at the time of mold release is inserted, and inside a cavity of the mold. A mold releasing device for a core, which comprises a gas releasing pin integrally formed with a pin portion for forming a gas releasing hole in the core, and the extruding pin. 2. The gas vent pin has a bolt hole,
The core mold releasing apparatus according to claim 1, further comprising a flange portion that is positioned on the mold. 3. The mold releasing apparatus for a core according to claim 2, wherein a head portion of the bolt is buried in the flange portion and a bolt groove communicating with the bolt hole is formed. 4. The guide portion comprises a cylindrical outer shell portion, a root portion of the pin portion, and a bridge portion connecting the outer shell portion and the root portion. Mold release device for cores.