JP7342464B2 - sand mold making machine - Google Patents

Description

The present invention belongs to the technical field related to sand mold making machines.

BACKGROUND ART Sand mold making machines for manufacturing sand molds have been well known (for example, see Patent Document 1). This sand mold making machine consists of a mold with a cavity, a blow tank (also called a blow head) that is placed above the mold and stores sand inside, and sand is fed into the blow tank by gravity. It is equipped with an input tube for The input pipe is usually arranged such that the outlet part faces the central region of the internal bottom surface of the blow tank with an interval above the center region.

The bottom wall of the blow tank is provided with a plurality of blow nozzles that supply sand inside the blow tank to the cavity of the mold. These plurality of blow nozzles are provided at substantially equal intervals from each other over substantially the entire bottom wall portion of the blow tank. Then, pressurized air is supplied to the space above the sand inside the blow tank, whereby the sand inside the blow tank is blown and filled into the cavity through the plurality of blow nozzles.

Japanese Patent Application Publication No. 2005-224833

Incidentally, the sand introduced into the blow tank through the above-mentioned input pipe is deposited in a mountain shape (conical shape) on the inner bottom surface of the blow tank. The angle of the slope of this pile of sand becomes the angle of repose, and the height of the pile of sand is set to a height such that sand is deposited on substantially the entire internal bottom surface of the blow tank. The distance between the outlet of the input pipe and the internal bottom of the blow tank is determined by the distance between the sand pile set as described above, from the viewpoint of reducing the height of the blow tank (and thus the size of the sand mold making machine). It is set to be approximately the same as the height. As a result, the sand deposited into the blow tank by the input pipe and deposited on the internal bottom of the blow tank forms a mountain shape with its apex at approximately the same height as the outlet of the input pipe (Figure 4). reference).

However, when sand is introduced into the blow tank using the input pipe, a large amount of sand accumulates in the central area of the internal bottom of the blow tank, while a small amount of sand accumulates in areas other than the central area. This means that there will be no accumulation.

In particular, when the mold cavity becomes larger in the horizontal direction, the blow tank also becomes larger in the horizontal direction corresponding to this cavity. In this case, the amount of sand deposited in areas other than the central area on the internal bottom surface of the blow tank is considerably reduced. Therefore, the amount of sand filled into the cavity from the blow nozzles corresponding to areas other than the central area on the internal bottom of the blow tank is smaller than the amount of sand filled into the cavity from the blow nozzles corresponding to the central area. Become. As a result, there is a problem that the sand is not filled uniformly into the cavity, and the sand mold cannot be formed properly.

Therefore, it is conceivable to increase the height of the sand pile deposited on the internal bottom surface of the blow tank so that a large amount of sand is deposited in areas other than the central area on the internal bottom surface of the blow tank.

However, in this case, the amount of sand deposited in the central region of the internal bottom of the blow tank becomes too large, and the sand located near the internal bottom in the central region is not sufficiently pressurized due to pressure loss. It disappears. As a result, the amount of sand filled into the cavity from the blow nozzle corresponding to the central area of the internal bottom of the blow tank is smaller than the amount of sand filled into the cavity from the blow nozzle corresponding to areas other than the central area. Become. Therefore, in this case as well, the sand is not filled uniformly into the cavity.

It is also conceivable to provide a plurality of input pipes so that sand is deposited substantially uniformly over substantially the entire internal bottom surface of the blow tank.

However, in this case, the conventional sand mold making machine would have to be significantly modified. That is, it is necessary to provide a hopper at the inlet of each input pipe, and a valve at the outlet of each input pipe. Additionally, a device for supplying sand to the hopper of each input pipe is also required. For this reason, the size of the sand mold making machine increases, and the cost of the sand mold making machine increases.

The present invention has been made in view of the above points, and its purpose is to modify the conventional sand mold making machine at low cost without increasing the size of the machine, and to create a mold in the central area of the internal bottom of the blow tank. The purpose is to reduce the difference between the amount of sand deposited and the amount of sand deposited in areas other than the central area.

In order to achieve the above object, the present invention provides a mold having a cavity, and a blow tank disposed above the mold and containing sand therein, the bottom wall of the blow tank having: A blow tank provided with a plurality of blow nozzles for supplying sand inside the blow tank to the cavity of the mold, and an input pipe for introducing sand into the blow tank by gravity. Aiming at a sand mold making machine, the input pipe includes a main input pipe portion, the outlet portion of which is arranged to face the central region of the internal bottom surface of the blow tank with an interval above, and the main input pipe portion. a plurality of sub-input pipe parts branching from the pipe part and arranged such that the outlet parts face each other at intervals above a plurality of regions other than the central region on the internal bottom surface of the blow tank; A portion of the main input pipe portion near the outlet portion extends linearly in the vertical direction, and the sub input pipe portion is located near the outlet portion of the main input pipe portion and extends from the outlet portion. The main input pipe is branched from the upper part and extends downward in a straight line with an inclination away from the vicinity of the outlet of the main input pipe part.

With the above configuration, the difference between the amount of sand deposited in the central area of the internal bottom of the blow tank and the amount of sand deposited in areas other than the central area is reduced by the main input pipe part and the plurality of sub-input pipe parts in the input pipe. can do. In addition, it is sufficient to simply replace the input pipe with respect to the conventional sand mold making machine, and the conventional sand mold making machine can be easily modified at low cost without increasing the size.

Additionally, when sand is introduced into the blow tank by the input pipe, the sand is first supplied into the blow tank from the main input pipe, and the sand is deposited on the internal bottom of the blow tank. It is deposited in the shape of a mountain with its apex at approximately the same height as the outlet of the main input pipe. Thereafter, sand is supplied from the sub-injection pipe toward the foot of the mountain-shaped sand pile, and the sand is deposited in the mountain-shape at the foot of the mountain. In this way, it is possible to reduce the difference between the amount of sand deposited in the central region of the internal bottom surface of the blow tank and the amount of sand deposited in regions other than the central region.

In the case where the sub-input pipe section is inclined and extends in a straight line as described above, the angle of the central axis of the sub-input pipe section on the acute side with respect to the horizontal is set to be larger than the angle of repose of the sand. , is preferable.

This suppresses sand clogging in the sub-injection pipe section, and enables the sub-input pipe section to smoothly charge sand into the interior of the blow tank.

Further, in an embodiment in which the sub-injection pipe section is inclined and extends linearly as described above, the shape of the internal bottom surface of the blow tank is approximately square, and the number of the sub-injection pipe sections is , and the four sub-input pipe sections extend from the main input pipe section so as to extend toward the four corners of the internal bottom surface of the blow tank, respectively, when viewed from above the blow tank. It's branching out.

With this, when the internal bottom surface of the blow tank has a substantially rectangular shape, the amount of sand deposited can be made substantially uniform over substantially the entire internal bottom surface of the blow tank.

In the above embodiment, the outlet portion of each of the sub-injection pipe sections is such that the outlet section of the main injection pipe section and the sub-input pipe section on the internal bottom surface of the blow tank face each other in a plan view from above the blow tank. It is preferable that it be located approximately in the center between the corners.

This makes it possible to make the amount of sand deposited more uniform over substantially the entire inner bottom surface of the blow tank.

Furthermore, in the case where the sub-input pipe section is inclined and extends linearly as described above, the outlet section of the sub-injection pipe section is located at approximately the same height position as the outlet section of the main input pipe section. It is preferable that the

By doing so, it is possible to further reduce the difference between the amount of sand deposited in the central area of the internal bottom surface of the blow tank and the amount of sand deposited in areas other than the central area.

As explained above, according to the sand mold making machine of the present invention, it is possible to reduce the difference between the amount of sand deposited in the central area of the internal bottom of the blow tank and the amount of sand deposited in areas other than the central area. As a result, it becomes possible to uniformly fill the cavity with sand using the blow nozzle. In addition, it is sufficient to simply replace the input pipe with respect to the conventional sand mold making machine, and the conventional sand mold making machine can be easily modified at low cost without increasing the size.

1 is a schematic cross-sectional view showing a sand mold making machine according to an embodiment of the present invention. 2 is a diagram cut along line II-II in FIG. 1. FIG. FIG. 2 is a view corresponding to FIG. 1 showing a state in which sand is introduced into the blow tank through an input pipe. FIG. 1 is a view corresponding to FIG. 1 showing a state in which sand is introduced into a blow tank through an input pipe of a conventional sand mold making machine. This is a diagram corresponding to FIG. 3.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 schematically shows a sand mold making machine 1 according to an embodiment of the present invention. This sand mold making machine 1 includes a mold 2 having a cavity 2a, a blow tank 3 disposed above the mold 2 and containing sand 21 (see FIG. 3), and a sand mold inside the blow tank 3. 21 by gravity.

The mold 2 includes an upper mold 2b and a lower mold 2c, and a cavity 2a is formed between the upper mold 2b and the lower mold 2c. The upper die 2b is formed with an insertion hole 2d into which a blow nozzle 3a, which will be described later, is inserted so as to face the cavity 2a.

In this embodiment, the internal bottom surface of the blow tank 3 is a horizontally extending substantially rectangular plane. The blow tank 3 has a substantially rectangular parallelepiped shape, and has substantially the same shape (square) and the same size as the mold 2 in plan view. Note that the shape of the internal bottom surface of the blow tank 3 is not limited to a substantially rectangular shape.

A plurality of blow nozzles 3a for supplying sand 21 inside the blow tank 3 to the cavity 2a of the mold 2 are provided on a bottom wall portion constituting the internal bottom surface of the blow tank 3. These plurality of blow nozzles 3a are provided at substantially equal intervals from each other over substantially the entire bottom wall portion of the blow tank 3. In addition, in FIGS. 1 and 3, the blow nozzles 3a are drawn larger and fewer in number than in reality for the sake of clarity.

The upper wall of the blow tank 3 is provided with an air supply pipe 6 for supplying pressurized air to the inside of the blow tank 3 and an air bleed pipe 7 for removing air from inside the blow tank 3. There is. After the sand 21 is introduced into the blow tank 3 through the input pipe 11, pressurized air is supplied into the blow tank 3 through the air supply pipe 6.

The air vent pipe 7 is provided with an on-off valve (not shown). This on-off valve opens before the sand 21 is introduced into the blow tank 3 by the input pipe 11, and closes after the sand 21 is introduced into the blow tank 3 and before pressurized air is supplied. It is configured.

When pressurized air is supplied to the inside of the blow tank 3, the sand 21 inside the blow tank 3 is blown into the cavity 2a together with the pressurized air through the plurality of blow nozzles 3a and filled. The lower die 2c of the mold 2 is provided with an air vent (not shown) through which only pressurized air escapes to the outside of the cavity 2a. Moreover, only pressurized air escapes to the outside of the cavity 2a from the mating surfaces of the upper mold 2b and the lower mold 2c.

The mold 2 is heated to a predetermined temperature or higher before the sand 21 is filled into the cavity 2a, and the sand 21 filled into the cavity 2a is sintered within the cavity 2a.

The input pipe 11 includes a main input pipe section 11a extending through the center of the upper wall of the blow tank 3, and a plurality of (in this embodiment, four) sub input pipe sections branched from the main input pipe section 11a. 11b.

In this embodiment, a portion of the main input pipe portion 11a near the outlet portion is a portion located inside the blow tank 3, and is a separate member from a portion of the main input pipe portion 11a located outside the blow tank 3. It consists of Hereinafter, a portion of the main input pipe portion 11a located inside the blow tank 3 will be referred to as an inner portion 11c, and a portion located outside the blow tank 3 will be referred to as an outer portion 11d.

The inner portion 11c of the main input pipe portion 11a extends linearly in the vertical direction. The outer part 11d can extend no matter how long it extends as long as the sand 21 naturally falls from a hopper (not shown) provided at the upper end of the main input pipe part 11a (outer part 11d) and reaches the inner part 11c. Good (basically extends in the vertical direction).

An on-off valve 13 that opens and closes the upper end of the inner part 11c is provided inside the input pipe 11 (main input pipe section 11a). The on-off valve 13 opens when the sand 21 is introduced into the blow tank 3 through the introduction pipe 11, and closes when a predetermined period of time has elapsed since the opening began. During this predetermined period of time, sand 21 is introduced into the blow tank 3 through the introduction pipe 11. The predetermined time is set to a time such that the amount of sand 21 required to completely fill the cavity 2a with sand 21 is introduced into the blow tank 3.

The main input pipe portion 11a is arranged such that the outlet portion of the main input pipe portion 11a faces the central region of the internal bottom surface of the blow tank 3 with an interval above. The four sub-injection pipe parts 11b are configured such that the outlet part of the sub-input pipe part 11b faces a plurality of (four) areas other than the central area on the internal bottom surface of the blow tank 3 at intervals above each other. It is located in The four sub-input pipe parts 11b extend in a straight line from the inner part 11c (the part below the on-off valve 13) of the main input pipe part 11a, slanting downward and away from the inner part 11c. ing.

In this embodiment, as shown in FIG. 2, the four sub-injection pipe parts 11b extend toward the four corners of the internal bottom surface of the blow tank 3, respectively, when viewed from above the blow tank 3. It branches off from the main input pipe section 11a. In addition, the outlet portion of each sub-injection pipe portion 11b is connected to the outlet portion of the main injection pipe portion 11a and the corner portion of the internal bottom surface of the blow tank 3 where the sub-input pipe portion 11b faces in a plan view from above the blow tank 3. It is located approximately in the center between. Furthermore, the outlet portions of the four auxiliary input tube portions 11b are cut horizontally and are located at approximately the same height as the outlet portion of the main input tube portion 11a. Furthermore, the inlet portions of the four sub-injection pipe portions 11b are located at the same height in the main injection pipe portion 11a (inner portion 11c) and at different portions in the circumferential direction. In addition, in FIG. 2, the illustration of the blow nozzle 3a is omitted.

The acute angle θ of the central axis of each sub-injection pipe portion 11b with respect to the horizontal is set to be larger than the repose angle α of the sand 21. This is because if the angle θ is less than the angle of repose α, the sand 21 will not flow within the sub-injection pipe portion 11b. The angle of repose α is determined by the particle size, shape, water content, etc. of the sand 21, and the angle of repose α of the sand 21 used in this embodiment is approximately 30°. The angle θ may be any value as long as it is larger than the angle of rest α, but if the position of the outlet of the sub-injection pipe portion 11b is determined, as the angle θ becomes larger, the length of the sub-injection pipe portion 11b becomes longer. , the position of the inlet portion of the sub-injection pipe portion 11b becomes higher. As a result, if the sub-injection pipe part 11b branches from the outer part 11d or if the sub-injection pipe part 11b branches from the inner part 11c, the length of the inner part 11c, and by extension the vertical direction of the blow tank 3. The length will become longer. Therefore, the angle θ is preferably a value slightly larger than the angle of rest α (for example, α+10° or less). In this embodiment, the angle θ is set to approximately 35°.

The diameter of each sub-input pipe section 11b is smaller than the diameter of the main input pipe section 11a. This is to make it easy for the four sub-input pipe parts 11b to branch from different parts in the circumferential direction at the same height in the main input pipe part 11a. The diameter of each sub-injection pipe section 11b may have any relationship with the diameter of the main introduction pipe section 11a, as long as the sand 21 flows within each sub-input pipe section 11b.

When the on-off valve 13 provided in the main input pipe section 11a opens, sand 21 is first supplied into the blow tank 3 from the main input pipe section 11a, and the sand 21 is deposited on the internal bottom surface of the blow tank 3. The particles are deposited in the shape of a mountain (conical shape) with the apex at approximately the same height as the outlet of the input pipe portion 11a. The angle of the slope of this pile of sand is the angle of repose α.

When the outlet of the main input pipe section 11a is blocked by sand 21, sand 21 is then supplied from the sub input pipe section 11b toward the foot portions (4 locations) of the sand pile piled up in the shape of a mountain. Sand 21 is deposited in the shape of a mountain at the hem (see FIG. 3). The angle of the slope of the sand pile thus accumulated at the foot also becomes the angle of repose α. Note that even before the outlet of the main input pipe section 11a is blocked by the sand 21, some of the sand 21 in the main input pipe section 11a may flow into the sub input pipe section 11b. This is because the air in the blow tank 3 may not be completely removed by the air bleed pipe 7, and air pressure may be applied to the outlet portion of the main input pipe portion 11a.

The on-off valve 13 is closed when the top of the pile of sand supplied and deposited from the outlet of the sub-input pipe section 11b is at approximately the same height as the outlet of the sub-input pipe section 11b. . In this way, the height of the pile of sand supplied from the outlet of the auxiliary input pipe section 11b and accumulated is approximately the same as the height of the pile of sand supplied and deposited from the outlet of the main input pipe section 11a.

After the sand 21 is introduced into the blow tank 3, the on-off valve provided in the air vent pipe 7 is closed, and then the air supply pipe 6 pressurizes the space above the sand 21 inside the blow tank 3. Air is supplied. As a result, the sand 21 inside the blow tank 3 is blown and filled into the cavity 2a through the plurality of blow nozzles 3a.

Here, FIG. 4 shows a case where sand 21 is introduced into the blow tank 3 through the input pipe 11' of the conventional sand mold making machine 1'. The conventional sand mold making machine 1' differs from the sand mold making machine 1 in that the charging pipe 11' does not have the sub-charging pipe part 11b as described above, and the other configurations are the same as the sand mold manufacturing machine 1. (The same reference numerals as in Fig. 1 are attached).

The sand 21 introduced into the blow tank 3 through the input pipe 11' is deposited in the shape of a mountain on the inner bottom surface of the blow tank 3. The angle of the slope of this pile of sand is the angle of repose α. The height of the sand pile is set so that the sand 21 is deposited on substantially the entire internal bottom surface of the blow tank 3.

When sand 21 is introduced into the blow tank 3 through the input pipe 11' in this way, a large amount of sand 21 accumulates in the central area of the internal bottom of the blow tank 3, while a large amount of sand 21 accumulates in areas other than the central area. Only a small amount of sand 21 will be deposited. In particular, when the cavity 2a of the mold 2 becomes larger in the horizontal direction, the blow tank 3 also becomes larger in the horizontal direction corresponding to the cavity 2a. In this case, the amount of sand 21 deposited in areas other than the central area on the internal bottom surface of the blow tank 3 is considerably reduced. Therefore, the amount of sand 21 filled into the cavity 2a from the blow nozzle 3a corresponding to the area other than the central area on the internal bottom surface of the blow tank 3 is the same as the amount of sand 21 filled into the cavity from the blow nozzle 3a corresponding to the central area. It will be less compared to the amount of

On the other hand, if the height of the sand pile deposited on the internal bottom of the blow tank 3 is increased and a large amount of sand 21 is deposited in areas other than the central area on the internal bottom of the blow tank 3, the internal bottom of the blow tank 3 The amount of sand 21 deposited in the central region becomes too large, and the sand 21 located near the internal bottom surface in the central region is no longer subjected to sufficient pressure due to pressure loss. As a result, the amount of sand 21 filled into the cavity 2a from the blow nozzle 3a corresponding to the central area of the internal bottom surface of the blow tank 3 is reduced from the amount of sand 21 filled into the cavity 2a from the blow nozzle 3a corresponding to areas other than the central area. The amount is smaller than that of 21.

When the sand 21 is introduced into the blow tank 3 through the injection pipe 11' in this way, the sand 21 is not evenly filled into the cavity 2a, making it impossible to form the sand mold properly.

On the other hand, in this embodiment, the central area on the internal bottom surface of the blow tank 3 and the four areas other than the central area on the internal bottom surface of the blow tank 3 (between the center and each corner on the internal bottom surface of the blow tank 3) Sand mounds of approximately the same height are formed in both the central and central areas. Therefore, the amount of sand 21 deposited can be made substantially uniform over substantially the entire internal bottom surface of the blow tank. As a result, the sand 21 is uniformly filled into the cavity 2a from the blow nozzle 3a, so that the sand mold can be formed satisfactorily.

In addition, it is only necessary to replace the charging pipe 11' of the conventional sand mold making machine 1' with the charging pipe 11, and the conventional sand mold making machine 1' can be easily modified at low cost without increasing the size. In particular, when the input pipe 11' is composed of an outer part 11d' and an inner part 11c' which is a separate member from the outer part 11d' (see FIG. 4), like the input pipe 11, It is sufficient to simply replace the inner part 11c' of the tube 11' with the inner part 11c provided with the sub-injection pipe part 11b, making the change even easier.

The present invention is not limited to the embodiments described above, and substitutions may be made without departing from the scope of the claims.

The above-described embodiments are merely illustrative and should not be construed as limiting the scope of the present invention. The scope of the invention is defined by the claims, and all modifications and changes that come within the range of equivalents of the claims are intended to be within the scope of the invention.

The present invention relates to a mold having a cavity and a blow tank disposed above the mold and containing sand therein, the sand inside the blow tank being deposited on the bottom wall of the blow tank. The present invention is useful for a sand mold making machine equipped with a blow tank provided with a plurality of blow nozzles for supplying sand to the cavity of a mold, and an input pipe for introducing sand into the blow tank by gravity.

1 Sand mold making machine 2 Molding mold 2a Cavity 3 Blow tank 3a Blow nozzle 11 Injection pipe 11a Main injection pipe part 11b Sub-injection pipe part

Claims (5)

a mold having a cavity;
A blow tank disposed above the mold and containing sand therein, wherein a plurality of blow nozzles are provided on the bottom wall of the blow tank to supply the sand inside the blow tank to the cavity of the mold. A blow tank equipped with
A sand mold making machine comprising: an input pipe for introducing sand into the blow tank by gravity,
The input pipe includes a main input pipe part, the outlet part of which is arranged to face the central area of the internal bottom surface of the blow tank with an interval above, and an outlet part which branches from the main input pipe part. is composed of a plurality of sub-injection pipe portions arranged so as to face each other at intervals above a plurality of regions other than the central region on the internal bottom surface of the blow tank,
A portion of the main input pipe section near the outlet section extends linearly in the vertical direction,
The auxiliary input pipe section branches from a portion near the outlet of the main input tube and above the outlet, and extends downward from a portion near the outlet of the main input tube. A sand mold making machine characterized by extending in a straight line and slanting away from the side . The sand mold making machine according to claim 1 ,
A sand mold making machine characterized in that an acute angle of the central axis of the sub-injection pipe section with respect to the horizontal is set to be larger than a repose angle of the sand. The sand mold making machine according to claim 1 or 2 ,
The shape of the internal bottom of the blow tank is approximately square,
The number of the sub-injection pipe parts is four,
The four sub-injection pipe sections are branched from the main input pipe section so as to extend toward the four corners of the internal bottom surface of the blow tank, respectively, when viewed in plan from above the blow tank. Characteristic sand mold making machine. The sand mold making machine according to claim 3 ,
The outlet portion of each of the auxiliary input pipe portions is located between the outlet portion of the main input tube portion and the corner portion of the internal bottom surface of the blow tank where the auxiliary input pipe portion faces, when viewed from above the blow tank. A sand mold making machine characterized by being located approximately in the center. In the sand mold making machine according to any one of claims 1 to 4 ,
A sand mold making machine characterized in that an outlet portion of the sub-input pipe section is located at approximately the same height as an outlet section of the main input pipe section.

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