JPH0222113Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement in a molding device used for manufacturing sand molds for casting, particularly cold box molds.

(Prior art) For example, when casting an engine cylinder block, etc., a sand mold for the core, etc. to be used must be manufactured in advance.The method for manufacturing this sand mold is the so-called cold box method, especially gas hardening. The cold box method of Eq.

This involves injecting molding sand coated with a resin into a mold, and then applying a curing gas such as amine gas blown into the molding sand from the outside to harden the sand at room temperature and form it into a predetermined shape. It was designed to obtain a sand mold. As shown in FIGS. 1 and 2, the molding device used in this method is provided with blow ports C...C for blowing the hardening gas into the molding sand in the cavity B in one mold A, and in the other mold A. Mold A' is configured to have exhaust passages E...E for discharging hardened gas with vent plugs D...D attached to the openings on the cavity B side. The curing gas is blown into the cavity B by being sucked from the outer opening of the exhaust passages E...E.
By forcefully distributing the air into the cavity B.
It is designed to harden the molding sand inside.

However, in the conventional molding apparatus as described above, each blow port C on the side of the cavity B,
There was a problem in that the intermediate portions F...F of C became blind areas where hardening gas did not sufficiently spread, and therefore the molding sand was not sufficiently hardened in these portions F...F.

(Purpose of the invention) The purpose of this invention is to deal with the above-mentioned problems in conventional molding equipment, and to ensure that the curing gas is sufficiently distributed even in the middle part between the blow ports on the side of the cavity. The object of the present invention is to sufficiently harden the foundry sand even in these parts, and to manufacture a sand mold without any poorly hardened parts on the surface.

(Structure of the invention) In order to achieve the above object, a cold box mold manufacturing apparatus according to the invention is structured as follows.

That is, in a molding device that uses a pair of molds in which a cavity is formed in the mating part, one mold is provided with a blow port for injecting hardening gas leading to the cavity, and the other is provided with an exhaust passage for discharging hardening gas.
A groove is formed on the mating surfaces of the pair of molds to communicate the inside of the cavity to the outside, corresponding to the middle part between the blow ports on the side of the cavity, and the mold is placed in a gas-sealed frame. At the same time, the frame is configured to suck air into the inside of the frame. According to such a configuration, since the curing gas in the cavity is also sucked out from the above-mentioned groove formed on the mating surface of the mold, the curing gas is also sucked out in the middle part between the blow ports on the side of the cavity. As a result, the molding sand in these parts is sufficiently hardened, and a mold without any poorly hardened parts can be obtained as a whole.

(Example) Hereinafter, a molding apparatus according to the present invention will be described based on an example shown in the drawings.

As shown in FIGS. 3 and 4, the molding device 1 includes a mold 1
0...10, and a frame 20 configured to house the molds 10...10 and to supply and discharge curing gas such as amine gas thereto.

Each of the molds 10 is composed of an upper mold 11 and a lower mold 12, and a cavity 13 is formed at the mating portion of the upper mold 11 and the lower mold 12. The upper mold 11 of the mold includes a cavity 13 from the upper surface.
Blow ports 14...14 for injecting hardening gas leading to the inside
are provided in large numbers, and the lower mold 12 is provided with a large number of exhaust passages 15 . . . 15 communicating from the inside of the cavity 13 to the lower surface. Incidentally, the openings of the exhaust passages 15...15 on the side of the cavity 13 are provided with vent plugs 16...16 each having a mesh on the upper surface to prevent leakage of molding sand.
is installed.

Grooves 17 . . . 17 are provided in the mating surfaces of the upper mold 11 and the lower mold 12 constituting the mold 10. In the case of the illustrated example, these grooves 17...17 are
They are provided on the mating surface 12a of No. 2 at positions corresponding to the intermediate portions a...a of the respective blow ports 14...14 on the sides of the cavity 13, allowing communication between the inside of the cavity 13 and the outside of the mold. Here, the groove 17...
17 is formed to be narrow in the depth direction and wide in the width direction to allow hardening gas to pass from inside the cavity 13 to the outside of the mold, but to prevent molding sand from leaking out.

Further, in this embodiment, the grooves 17...17
is provided on the mating surface 12a of the lower mold 12,
The grooves 17...17 may be provided on the mating surface on the upper die 11 side.

On the other hand, the frame 20 is composed of a side wall part 21, a lid body 22 and a bottom body 23 which have spaces b and c inside, respectively, and which sandwich the side wall part 21 from above and below. The joints between the side wall portion 21, the lid body 22, and the bottom body 23 are gas-sealed to prevent curing gas from leaking from the space d of the molds 10...10. It is now possible to separate. and,
The lid body 22 is provided with a curing gas inlet 22b on the upper surface 22a, and a plurality of curing gases are supplied on the lower surface 22c at positions corresponding to the openings of the blow ports 14...14 on the upper surface of the upper mold 11. Holes 22d...22d for use are provided. In addition, the bottom body 23 has a plurality of hardening gas suction holes 23b...23b located on the upper surface 23a corresponding to the openings of the discharge ports 15...15 on the lower surface of the lower mold 12,
Holes 23c...23c for sucking the hardening gas are arranged scattered around the installation location of each mold 10...10, and a hardening gas suction port 23e is provided on the lower surface 23d. Note that the joints between the holes 22d...22d in the lid 22 and the blow ports 14...14 in the upper die 11, and the holes 23d...23d in the bottom body 23 and the exhaust passage 1 in the lower die 12
Each of the joints 5...15 is sealed to prevent curing gas from leaking from these joints. In addition, nets 23f, . . . , 23f for preventing molding sand, etc. from falling are stretched over the hardening gas suction holes 23c, . The curing gas inlet 22b and curing gas suction port 23e provided on the lid 22 and the bottom body 23 are respectively connected to a separately provided curing gas supply device and a curing gas suction device (both not shown). has been done.

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

First, in the pre-process, molding sand is injected into the cavity 13 of each mold 10, and the mold 10 is placed on the bottom body 23 of the frame 20 as shown in FIG. A lid body 22 is placed above the side wall portion 21.
Set. In this state, the lid body 22
When curing gas is injected from the injection port 22b on the upper surface 22a, the curing gas is blown into the upper mold 11 through the internal space b of the lid 22 and the curing gas injection holes 22d...22d provided in the lower surface 22c. It is injected into the cavity 13 from ports 14...14.

On the other hand, suction force from a separately provided curing gas suction device (not shown) is acting on the internal space c of the bottom body 23 in the frame 20 through the curing gas suction port 23e. The hardening gas inside the exhaust passages 15...15 of the lower mold 12 and the holes 23b...23b provided in the upper surface 23a of the bottom body 23 are
The curing gas is sucked into the internal space c of the bottom body 23 through the suction port 23e, and then collected into a separately provided curing gas suction device. As a result, in the cavity 13, the exhaust passages 15...15 of the lower die 12 are connected from the blow ports 14...14 of the upper die 11 to the exhaust passages 15...15 of the lower die 12.
A hardening gas flows, which acts on the foundry sand in the cavity 13 to harden the sand.

However, with only the flow of the curing gas as described above, the blow ports 14...1 at the side of the cavity 13
4, the gas is not sufficiently distributed to the intermediate portions a...a of the mold 10 (lower mold 12).
The mating surface 12a) is provided with grooves 17...17 that communicate the interior of the cavity 13 with the outside in correspondence with the intermediate portions a...a of the blow ports 14...14 on the sides of the cavity 13. The interior d of the frame 20 in which the mold 10 is installed includes the holes 23c...23c in the bottom body 23, the interior space c, and the suction port 2.
3e by the suction device to create a negative pressure, the curing gas injected into the cavity 13 from the blow ports 14...14 is also sucked out of the mold from the grooves 17...17. It will be served. As a result, the curing gas can also flow well to the intermediate portions a...a of the respective blow ports 14...14 on the sides of the cavity 13, and accordingly, the castings present in the portions a...a The sand will also be sufficiently hardened.

After the molding sand has been hardened as described above, it is removed from the mold in the next step, and in this case, a mold with no poorly hardened portions is obtained as a whole.

(Effects of the invention) As described above, according to the invention, a large number of grooves formed on the mating surface of the mold at positions corresponding to the intermediate portions between the blow ports on the side of the cavity can also be inserted into the cavity. Since the curing gas is sucked out, the circulation of the curing gas also becomes good in the middle part of each blow port in the side part of the cavity. As a result, it is possible to sufficiently harden the foundry sand even in the intermediate portions between the blow ports, where it was not possible to harden the foundry sand sufficiently with conventional mold making equipment, and as a whole, the sand is not hardened properly. This results in a mold free of blemishes.

[Brief explanation of the drawing]

1 and 2 are a plan view and a vertical sectional view showing a conventional mold making device, and FIGS. 3 and 4 are a schematic vertical sectional view and a plan view of essential parts of the mold making device of the present invention. 1... Molding device, 10... Mold, 13... Cavity, 14... Blow mouth, 17... Groove, 20...
…frame.

Claims (1)

[Scope of utility model registration request] A molding device that uses a pair of molds in which a cavity is formed in a mating part and one of which is provided with a number of blow ports for injecting hardening gas that communicates with the cavity, the molding apparatus having a cavity side part on the mating surface of the pair of molds. A groove is formed to communicate the inside of the cavity to the outside, corresponding to the intermediate part between the blow ports, and this mold is installed in a gas-sealed frame, and the inside of the frame is air-intake. A cold box mold making device characterized in that it is configured to