JPH0760400A - Structure for mounting core for casting - Google Patents

Abstract

PURPOSE:To provide the structure for mounting a core for casting capable of exactly holding the core in a specific position in a casting mold at all times without the need for frequently changing elastic members. CONSTITUTION:This mounting structure 2 for the core for casting is formed by fitting hanging rubber 30 to a core print 24 of a circular conical shape disposed at the core 22 and fitting a chucking mechanism 10 consisting of a chucking ring 12, pawl members 14 and chucking base 16 around this rubber. While the three pawl members 14A, 14B, 14C are simultaneously pressed, the pawl members are pressed inward and the hanging rubber 30 is tightened from three sides when the chucking ring 13 is screwed onto the chucking base 16. The rear surface of the chucking base 16 is a permanent magnet of an N pole. The front surface thereof is floated by a distance C from a die plate 20 by the repulsive force of the N pole and a magnet ring 18. Then, the tightening force of the hanging rubber 30 is made up without downward shifting of the core 22. The force to hold the core print 24 is thus assured even if the elastic force of the hanging rubber 30 degrades by heating or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting core mounting structure for holding a core used in casting at a predetermined position in a mold.

[0002]

2. Description of the Related Art In casting, as a core, a so-called shell sand obtained by coating a sand with a thermosetting resin such as phenol resin is filled in a mold of a predetermined shape and thermoset to be used. To be Casting is performed by injecting a molten metal into the mold while holding such a core at a predetermined position in the mold. At this time, the heat of the molten metal further heats the cured resin in the shell sand to thermally decompose it, so that the core becomes fragile. After the casting is cooled and solidified, the core is crushed and discharged from the opening of the casting. In this way, casting using the core is performed. An example of such casting is the casting of a cylinder block of an automobile engine, in which a core is used to form a water jacket portion in the cylinder block wall.

As a method of attaching such a casting core to a mold, for example, there is an invention of a method of attaching a sand core in a mold and an attaching device described in JP-A-1-95842. The technique described in this publication will be described with reference to FIGS. FIG. 3 is a vertical cross-sectional view showing the overall structure of a casting mold to which a casting core is attached by a conventional method. As shown in FIG. 3, the casting mold 102 includes a mold plate 104 and an upper mold 10.
6, and three parts of the lower mold 108. By combining the mold plate 104, the upper mold 106, and the lower mold 108, a cavity 110 corresponding to the shape of the cast product is formed in the mold 102. A core 122 having a shape corresponding to the internal structure of the cast product is suspended and held in the cavity 110. On the upper surface of the core 122, one or two or more baseboards 124 having a conical shape with the tip cut off are provided so as to project. This baseboard 12
Similarly to the core 122, the shell No. 4 has a hardened shell sand and is molded integrally with the core 122. On the other hand, the mold plate 104 is provided with a mounting hole 104a having a shape corresponding to the baseboard 124.

When mounting the core 122, the skirting board 124 is attached to the mounting hole 10 from the inside of the mold plate 104.
4a is penetrated. Then, a hanging member (hanging rubber) 130 made of a cylindrical elastic rubber is fitted to the upper end portion of the skirting board 124 protruding upward from the mounting hole 104a and pressed against the upper surface of the mold plate 104. Fixed. As a result, the skirting board 124 is clamped and fixed by the hanging rubber 130, and the core 122 is fixed to the mold 10.
It is hung and held in 2. Here, hanging rubber 1
Since 30 is fitted on the outer periphery of the skirting board 124 and pressed against the upper surface of the mold plate 104, stress is not concentrated on a part of the skirting board 124. Therefore,
The weight of the core 122 can be supported without destroying the skirting board 124. In this way, the core 122 is held in the mold 102, and the cast product is cast.

FIG. 4 and FIG. 5 show, as a specific example of such a mounting structure for a casting core, mounting of a core used for forming a water jacket portion in a cast product of a cylinder block of an automobile engine. It shows the structure. As shown in FIG. 4 (C), when casting a cylinder block of an automobile engine, a core 122 molded from shell sand is used in conformity with the shape of the water jacket portion. A plurality of projecting skirting boards 124 are integrally provided on the upper surface of the core 122. Since the core 122 is extracted by dividing the cast cylinder block, as shown in FIG. 5 (B), the baseboard 124 is provided with a removal taper θ and has a conical shape with the tip cut. Has become.

On the other hand, the mold plate 104 of the cylinder block mold is provided with a plurality of mounting holes 104a corresponding to the arrangement of the skirting boards 124. The mold plate 1
04 also includes a plurality of holes 104b for installing bore inserts in the cylinder block. Now, when setting this core 122 in the mold, a plurality of baseboards 12
4 is inserted into and penetrates the mounting hole 104a from the inside of the mold plate 104. Then, as shown in FIGS. 4 and 5, a cylindrical suspending rubber 130 is fitted to the upper end portion of the skirting board 124 projecting upward from the mounting hole 104a and pressed against the upper surface of the mold plate 104. And fixed. In this way, core 1 for water jacket
22 is suspended and held in the mold to perform casting.

[0007]

However, in such a casting core mounting structure, the mold plate 104 is heated to a high temperature due to contact with a high-temperature molten metal during casting, and the hanging rubber 130 is also heated. Therefore, the hanging rubber 130 is deteriorated by heat, and the elastic force necessary for holding the weight of the core 122 is lost by casting several times. When such a deteriorated hanging rubber 130 is used, as shown in FIG. 5A, the weight of the core 122 causes the skirting board 124 to fall out of the hanging rubber 130, so that the height of the core 122 increases. It will be displaced from the predetermined position by Δ. In order to prevent such a problem, it is necessary to replace all of the plurality of hanging rubbers 130 to 130 after every one or two castings, which causes a problem that the manufacturing cost of the cast product becomes extremely high. Therefore, it is an object of the present invention to provide a mounting structure for a casting core that does not require frequent replacement of the elastic member and that can always hold the core at a predetermined position in the mold accurately. .

[0008]

Therefore, in the invention described in claim 1 of the present application, in order to solve the above-mentioned problems, the casting core is provided with a mounting portion projecting from the casting core. A mounting structure for a casting core for holding the core at a predetermined position in the mold by penetrating the mounting hole, and fitting an elastic member to a protruding portion of the mounting portion from the mounting hole. Therefore, a mounting structure for a casting core is created which is provided with a tightening means for tightening the elastic member from the outside of the elastic member.

In order to solve the above-mentioned problems, in the invention described in claim 2 of the present application, the mounting portion projecting from the casting core is penetrated into the mounting hole provided in the mold. When the mounting portion is protruded from the mounting hole when provided, an uneven portion extending in a direction perpendicular to the protruding direction of the mounting portion is provided, and a thermosetting resin-mixed sand is provided around the uneven portion. A mounting structure for a casting core, which is characterized by being filled and thermally cured, was created. Here, the uneven portion means that unevenness exists in the mounting portion of the core, and not only when both the concave portion and the convex portion are provided in the mounting portion, only the concave portion, Alternatively, the case where only the convex portion is provided is also included.

[0010]

In the mounting structure for the casting core according to the first aspect of the present invention, the mounting portion projecting from the casting core is passed through the mounting hole provided in the mold for mounting. The core is held at a predetermined position in the mold by fitting the elastic member to the protruding portion from the attachment hole of the part. Here, on the outside of the elastic member, tightening means for tightening the elastic member from the outside is provided. Therefore,
Even when the elastic member is deteriorated due to heating during casting and the elastic force is reduced, the tightening force of the elastic member is compensated by this tightening means, and the tightening force necessary to suspend and hold the core is provided. Reserved. Therefore, even if the elastic member is repeatedly used and deterioration of the elastic member progresses,
The core can always be held in place in the mold.
This eliminates the need for frequent replacement of elastic members,
Moreover, the casting core mounting structure can always hold the core in a predetermined position in the mold accurately.

Further, in the casting core mounting structure according to the second aspect of the invention, the mounting portion is provided when the mounting portion projecting from the casting core is passed through the mounting hole provided in the mold. An uneven portion extending in a direction perpendicular to the protruding direction of the mounting portion is provided at a portion protruding from the mounting hole. Thermosetting resin-mixed sand is filled around the concave portions and convex portions provided in the mounting portion, and is thermoset. At this time, since the thermosetting resin-containing sand also enters the periphery of the recesses and protrusions and is heat-set, the weight of the core is supported and held by the engagement of the intruded portion with the recesses and protrusions. . As described above, in the casting core mounting structure according to the second aspect, since the core can be held without using the elastic member, the casting cost can be further reduced. Not only that, because the sand containing thermosetting resin is hardened by heat and meshes with the concave and convex parts provided in the mounting part, it does not cause displacement even if the weight of the core is large, and it is more precise. It is possible to position a fine core.

[0012]

【Example】

Example 1 Next, Example 1 embodying the present invention will be described with reference to FIG. FIG. 1 is a diagram showing the configuration of a first embodiment of a mounting structure for a casting core according to the present invention. Figure 1 (A)
FIG. 1 is a vertical cross-sectional view showing a main part of Example 1 of a mounting structure for a casting core, and FIG. 1 (B) is II of FIG. 1 (A).
FIG. As shown in FIG. 1 (A), in the mounting structure 2 for the casting core in this embodiment, the core 2 is
A hanging rubber 30 made of elastic rubber having a cylindrical shape is fitted to a conical skirting board 24 having a conical shape and having a tip cut off, which is provided so as to protrude from the upper surface of 2. The chuck mechanism 10 is fitted around the hanging rubber 30. The chuck mechanism 10 is configured by combining a chuck ring 12, a claw member 14 and a chuck base 16. The claw member 14 is a wedge-shaped member, and as shown in FIG. 1B, three claws 14A, 14B, and 14C are arranged at positions that divide the circumference into three equal parts. These three claw members 1
4A, 14B and 14C are housed in claw holes 16b provided at three locations of the chuck base 16.

On the other hand, a threaded portion 16a is provided in the cylindrical thin portion extending above the chuck base 16. The screw portion 12a of the chuck ring 12 is screwed into the screw portion 16a, and the lower surface 12b of the chuck ring 12 is slightly apart from the upper surface 14a of the claw member 14 in the original position. Further, the lower portion of the chuck base 16 is a permanent magnet having an N pole on the lower surface, and a magnet ring 18 is fixed around the mounting hole 20a provided in the mold plate 20. This magnet ring 18 is also a permanent magnet, and its upper surface is the N pole of the magnet. Therefore, due to the repulsive force between the N poles, the chuck base 16 floats above the magnet ring 18 by a certain distance C.

Now, the chuck mechanism 1 having such a structure
The function of 0 will be described. When the chuck ring 12 is rotated in the clockwise direction, the screw portion 12a is screwed into the screw portion 16a of the chuck base 16 and moves downward. The chuck ring lower surface 12b is the upper surface 1 of the claw member 14.
The four claw members 14A, 14B, and 14C are simultaneously pressed down by the chuck ring 12 by abutting against the 4a.
Here, as shown in FIG. 1A, the contact surface 14b of the claw member 14 with the claw hole 16b of the chuck base 16 is a tapered surface. Therefore, when the claw member 14 is pushed down by the chuck ring 12, the claw member 14 is moved to the position shown in FIG.
As indicated by the chain double-dashed line in (A), it is pressed inward. As a result, the circumference of the hanging rubber 30 is tightened from three sides by the three claw members 14A, 14B, 14C, and the hanging rubber 30 is pressed toward the skirting board 24.

At this time, a downward component force also acts on the chuck base 16 via the tapered surface of the claw hole 16b. However, as described above, the permanent magnet portion of the chuck base 16 is subjected to the repulsive force between the permanent magnet portion and the magnet ring 18 fixed to the mold plate 20, so that the height of the chuck base 16 itself is displaced. There is no. Also,
Since the claw member 14 slides with respect to the outer peripheral surface of the hanging rubber 30 when pushed down, the hanging rubber 30 does not descend together with the claw member 14. As a result, baseboard 2
4. Consequently, the force for tightening the suspension rubber 30 is applied without changing the mounting height of the core 22 to the mold plate 20. The function of the chuck mechanism 10 supplements the force for holding the skirting board 24 even when the elastic force of the hanging rubber 30 is lowered due to heating or the like. Therefore, it is possible to compensate for the decrease in elastic force due to the deterioration of the hanging rubber 30, and it is possible to repeatedly use the rubber. As described above, according to the casting core mounting structure 2 of the present embodiment, it is possible to always accurately and accurately hold the core 22 at a predetermined position in the mold without frequently changing the hanging rubber 30. it can. And
Since the chuck mechanism 10 can be repeatedly used semipermanently, the cost of casting can be significantly reduced.

Second Embodiment Next, a second embodiment embodying the present invention will be described with reference to FIG. FIG. 2 is a diagram showing a second embodiment of the mounting structure for the casting core according to the present invention. 2A is a vertical cross-sectional view showing the structure of the skirting board according to the second embodiment.
(B) is a longitudinal sectional view showing a mounted state. Figure 2
In this embodiment, as shown in FIG.
A plurality of cut grooves 56 having a width H and a depth D extending in the horizontal direction are provided on the outer peripheral surface of a conical baseboard 54 having a tip cut off, which is provided so as to project on the upper surface of 2. In this embodiment, as shown in FIG. 2 (B), the suspending rubber used in the conventional example and the first embodiment is not used, and shell sand 60 is filled around the skirting board 54 having the kerf 56. Then, the core 52 is held by being thermally cured.

That is, first, as in the first embodiment, the skirting board 54 is attached to the mounting hole 5 formed in the mold plate 50 of the mold.
0a is inserted. Then, the cylindrical frame 42 is attached around the skirting board 54 protruding from the upper surface of the mold plate 50. Shell sand 60 is filled in the cylindrical frame 42 and heat-cured by being heated from the outside. As the shell sand 60, the same sand as the shell sand in which the core 52 and the skirting board 54 are formed may be sand coated with a thermosetting resin. As a result, a cylindrical mounting portion made of thermosetting shell sand is formed around the baseboard 54. At this time, the shell sand 60 is also filled in the cut groove 56 of the skirting board 54, and the portion 62 that has entered the cut groove 56 is also thermoset integrally. The weight of the core 52 is supported by the meshing of the entering portion 62 and the cut groove 56, and the core 52 is suspended and held at a predetermined height.

As described above, in the casting core mounting structure 40 of the second embodiment, since the core 52 can be suspended and held without using a suspending rubber, the manufacturing cost of the cast product can be further reduced. be able to. Furthermore, by fixing the skirting board 54 by thermosetting the shell sand 60, displacement is less likely to occur as compared with attachment using a hanging rubber that utilizes elastic force. Therefore, even if the weight of the core 52 is large, it is possible to perform accurate positioning, prevent variation in wall thickness of the cast product, and enable more precise production of the cast product. The width H and the depth D of the kerf 56 are determined by the core 52.
It can be set to an optimum size according to the weight of the. Further, in the present embodiment, an example in which the cut groove 56 as the concave portion is provided as the uneven portion provided in the mounting portion is shown, but the convex portion may be provided at the same position as the cut groove 56, Further, it goes without saying that both the concave portion and the convex portion may be provided.

In each of the above-mentioned embodiments, an example in which the shape of the skirting board is a conical shape with the tip cut is shown. However, starting from the shape of the skirting board, the dimensions, number, arrangement, etc. of the skirting board are The present invention is not limited to each example. Further, although the case has been described in which the skirting board is attached only to the upper surface of the core and the core is suspended and held, the skirting board may be provided and held on another surface of the core. The number of claw members of the chuck mechanism, the structure of the tightening means, and the like can be variously selected.
The structure, shape, size, material, number, arrangement, etc. of the other parts of the casting core mounting structure are not limited to those of the above embodiments.

[0020]

According to the first aspect of the present invention, the mounting structure for a casting core is characterized in that a fastening means is provided around an elastic member for fastening the mounting portion provided on the casting core with an elastic force. Therefore, even when the elastic force is repeatedly used and the elastic force is reduced, the force by which the elastic member tightens the mounting portion of the core is always secured. As a result, the core can always be held accurately at a predetermined position in the mold without increasing the casting cost due to frequent replacement of the elastic member, and a cast product of accurate dimensions can be obtained at a low running cost. Obtainable.

According to the second aspect of the present invention, the mounting portion of the core is provided with a concavo-convex portion extending in a direction perpendicular to the projecting direction of the mounting portion, and instead of the elastic member, the periphery of the concavo-convex portion is provided. Since a mounting structure for a casting core, in which the sand containing thermosetting resin is thermoset and hardened, is created, the casting cost can be further reduced. Not only that, but because the thermosetting resin-blended sand is held by being hardened by heat, the core is positioned more accurately than when using a hanging rubber that uses elastic force, and it is extremely practical for casting. It has a core mounting structure.

[Brief description of drawings]

1A and 1B are a longitudinal sectional view and a transverse sectional view showing a configuration of a first embodiment of a casting core mounting structure according to the present invention.

FIG. 2 is a vertical sectional view showing a second embodiment of a casting core mounting structure.

FIG. 3 is a vertical cross-sectional view showing an overall structure of a casting mold using a conventional casting core mounting structure.

4A and 4B are a plan view and a front view showing a structure of a mold plate and a core in a conventional casting core mounting structure.

5A and 5B are a front view and a vertical cross-sectional view showing a conventional mounting structure for a casting core.

[Explanation of symbols]

 2, 40 Mounting structure of casting core 10 Tightening means (chuck mechanism) 20, 50 Mold (mold plate) 20a, 50a Mounting hole 22, 52 Core 24, 54 Mounting part (skirting board) 30 Elastic member (suspension) Rubber) 56 Concavo-convex part (kerf) 60 Thermosetting resin compounded sand

Claims (2)

[Claims] 1. An elastic member is fitted to a portion of the mounting portion projecting from the mounting hole by penetrating a mounting portion provided on the casting core so as to project from the mounting hole provided in the mold. Is a mounting structure for a casting core that holds the core at a predetermined position in the mold by means of providing a tightening means for tightening the elastic member from the outside of the elastic member. Mounting structure. 2. A projecting direction of the mounting portion at a portion where the mounting portion projects from the mounting hole when the mounting portion projecting from the casting core penetrates the mounting hole provided in the mold. A mounting structure for a casting core, characterized in that a concavo-convex portion extending in a direction perpendicular to is provided, and the concavo-convex portion is filled with thermosetting resin-mixed sand and thermally cured.