JP2996066B2 - Mounting structure for core for casting - Google Patents

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, a so-called shell sand in which sand is coated with a thermosetting resin such as a phenol resin is filled into a mold having a predetermined shape, and the core is thermoset to form a core. Can be With such a core held at a predetermined position in the mold, casting is performed by pouring the molten metal into the mold. At this time, the cured resin in the shell sand is further heated and thermally decomposed by the heat of the molten metal, so that the core is in a fragile state. After the casting is cooled and solidified, the core is crushed and discharged from the opening of the casting. Thus, casting using the core is performed. As an example of such casting, there is an example in which a core is used to form a water jacket portion in a cylinder block wall in casting a cylinder block of an automobile engine.

As a method of attaching such a casting core to a mold, there is, for example, a method of attaching a sand core in a mold and an invention of an attaching device described in Japanese Patent Laid-Open No. 1-95842. The technique described in this publication will be described with reference to FIGS. FIG. 3 is a longitudinal sectional view showing the entire configuration 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 the lower mold 108. The mold plate 104, the upper mold 106, and the lower mold 108 are combined to form a cavity 110 in the mold 102 corresponding to the shape of the casting. A core 122 having a shape corresponding to the internal structure of the casting is suspended and held in the cavity 110. On the upper surface of the core 122, one or two or more conical baseboards 124 each having a cut end are protrudingly provided. This baseboard 12
Similarly to the core 122, the shell sand is hardened and is formed integrally with the core 122. On the other hand, the mold plate 104 is provided with a mounting hole 104 a having a shape corresponding to the baseboard 124.

When mounting the core 122, the baseboard 124 is attached to the mounting hole 10 from the inside of the mold plate 104.
4a. A cylindrical hanging member (suspension rubber) 130 made of elastic rubber is fitted to an upper end portion of the baseboard 124 protruding upward from the mounting hole 104 a so as to be pressed against the upper surface of the mold plate 104. Fixed. As a result, the baseboard 124 is fastened and fixed by the hanging rubber 130, and the core 122 is
2 and is suspended. Here, the suspension rubber 1
Since 30 is fitted on the outer periphery of the baseboard 124 and pressed against the upper surface of the mold plate 104, stress does not concentrate on a part of the baseboard 124. Therefore,
The weight of the core 122 can be supported without the baseboard 124 being destroyed. In this way, the core 122 is held in the mold 102, and the casting is cast.

FIGS. 4 and 5 show a specific example of such a mounting structure of a core for mounting. The mounting of a core used to form a water jacket portion in a cast product of a cylinder block of an automobile engine is shown in FIGS. It shows the structure. As shown in FIG. 4C, when casting a cylinder block of an automobile engine, a core 122 molded from shell sand is used in accordance with the shape of the water jacket portion. A plurality of protruding baseboards 124 are integrally provided on the upper surface of the core 122. Since the core 122 is cut out by dividing the cast cylinder block, as shown in FIG. 5 (B), the baseboard 124 is provided with a cutting taper θ, and has a conical shape with a cut end. 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 baseboard 124. The mold plate 1
04 also has a plurality of holes 104b for installing bore inserts in the cylinder block. When the core 122 is set in the mold, a plurality of baseboards 12 are required.
4 is inserted and penetrated from the inside of the mold plate 104 into the mounting hole 104a. As shown in FIGS. 4 and 5, a cylindrical hanging rubber 130 is fitted to the upper end portion of the baseboard 124 projecting upward from the mounting hole 104a, and pressed against the upper surface of the mold plate 104. And fixed. Thus, the core 1 for the water jacket
22 is suspended in a mold and casting is performed.

[0007]

However, in such a mounting structure for a casting core, the mold plate 104 becomes hot due to the contact of the high-temperature molten metal during casting, and the suspension rubber 130 is also heated. For this reason, the hanging rubber 130 is deteriorated by heat, and the elastic force necessary to hold the weight of the core 122 is lost by several castings. When such a deteriorated hanging rubber 130 is used, as shown in FIG. 5A, the baseboard 124 falls off the hanging rubber 130 due to the weight of the core 122, and the height of the core 122 is reduced. It is shifted downward by Δ from the predetermined position. In order to prevent such a problem, it is necessary to replace all of the plurality of hanging rubbers 130 to 130 every one or two times of casting, and there is a problem that the manufacturing cost of the cast product is significantly increased. In view of the foregoing, an object of the present invention is to provide a mounting structure for a casting core, which does not require frequent replacement of the elastic member, and 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 problem, an attachment portion projecting from a casting core is provided on a mold. A casting core mounting structure for holding the core at a predetermined position in the mold by penetrating through the mounting hole provided and fitting an elastic member to a protruding portion of the mounting portion from the mounting hole. In addition, there is provided a mounting structure for a casting core, wherein a fastening means for fastening the elastic member from the outside of the elastic member is provided.

In the invention described in claim 2 of the present application, in order to solve the above-mentioned problem, a mounting portion protrudingly provided on a casting core is passed through a mounting hole provided in a mold. When the mounting portion protrudes from the mounting hole, an uneven portion extending in a direction perpendicular to a direction in which the mounting portion protrudes is provided at a portion where the mounting portion protrudes from the mounting hole. A casting core mounting structure characterized by being filled and thermally cured has been created. Here, the concave and convex portions mean that there are irregularities 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, but only in the concave portion. Alternatively, this includes the case where only the convex portion is provided.

[0010]

In the mounting structure for a casting core according to the first aspect of the present invention, the mounting portion protruding from the casting core is passed through a mounting hole provided in the casting mold. The core is held at a predetermined position in the mold by fitting an elastic member to a protruding portion of the portion from the mounting hole. Here, a fastening means for fastening the elastic member from outside is provided outside the elastic member. 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 supplemented by the tightening means, and the tightening force necessary to suspend and hold the core is reduced. Secured. Therefore, even if the elastic member deteriorates due to repeated use of the elastic member,
The core can always be held in place in the mold.
This eliminates the need for frequent replacement of the elastic member,
In addition, the core for casting can be attached to the core at a predetermined position in the mold.

In the mounting structure for a casting core according to the present invention, when the mounting portion protruding from the casting core is passed through a mounting hole provided in the mold, the mounting portion is formed. Are provided with projections and depressions extending in a direction perpendicular to the direction in which the mounting portion protrudes from the portion protruding from the mounting hole. The periphery of the concave portion and the convex portion provided in the attachment portion is filled with a thermosetting resin-containing sand, and is thermally cured. At this time, since the thermosetting resin-containing sand also enters the periphery of the concave portion and the convex portion and is thermoset, the weight of the core is supported and held by the engagement of the entered portion with the concave portion and the convex portion. . Thus, in the casting core mounting structure according to the second aspect, since the core can be held without using an elastic member, the casting cost can be further reduced. Not only that, since the sand containing the thermosetting resin is heat-cured and meshes with the concave and convex parts provided in the mounting part, even if the core weight is large, there is no displacement and more precise It is possible to position the core properly.

[0012]

【Example】

First Embodiment Next, a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing the configuration of Embodiment 1 of the mounting structure for a casting core according to the present invention. FIG. 1 (A)
1 is a longitudinal sectional view showing a main part of Embodiment 1 of a mounting structure for a casting core, and FIG. 1B is a sectional view taken along a line II of FIG.
It is sectional drawing. As shown in FIG. 1A, in the mounting structure 2 for a casting core in the present embodiment, the core 2
A suspension rubber 30 made of elastic rubber having a cylindrical shape is fitted to a conical baseboard 24 having a truncated tip, which is provided to protrude from the upper surface of 2. The chuck mechanism 10 is fitted around the suspension 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 accommodated in claw holes 16b provided at three places of the chuck base 16.

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

Now, a chuck mechanism 1 having such a structure.
The function of 0 will be described. When the chuck ring 12 is rotated clockwise, the screw portion 12a is screwed into the screw portion 16a of the chuck base 16 and moves downward. The lower surface 12 b of the chuck ring is the upper surface 1 of the claw member 14.
The three claw members 14A, 14B, and 14C are simultaneously pressed down by the chuck ring 12 while being in contact with 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
As shown by a two-dot chain line in FIG. Thereby, the periphery of the hanging rubber 30 is tightened from three directions by the three claw members 14A, 14B, 14C, and the hanging rubber 30 is pressed toward the baseboard 24.

At this time, a downward component force acts on the chuck base 16 via the tapered surface of the claw hole 16b. However, as described above, since the repulsive force between the permanent magnet portion of the chuck base 16 and the magnet ring 18 fixed to the mold plate 20 is acting, the height of the chuck base 16 itself shifts. There is no. Also,
When the claw member 14 is pushed down, it slides on the outer peripheral surface of the suspension rubber 30, so that the suspension rubber 30 does not drop together with the claw member 14. As a result, baseboard 2
4 and thus a force for tightening the suspension rubber 30 is applied without changing the mounting height of the core 22 to the mold plate 20. By the function of the chuck mechanism 10, even when the elastic force of the suspension rubber 30 is reduced due to heating or the like, the force for holding the baseboard 24 is supplemented. Therefore, it is possible to compensate for a decrease in elastic force due to the deterioration of the suspension rubber 30, and it is possible to use the suspension rubber 30 repeatedly. As described above, according to the mounting structure 2 of the casting core of the present embodiment, the core 22 can be always accurately held 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 of the present invention will be described with reference to FIG. FIG. 2 is a view showing a second embodiment of the mounting structure for a casting core according to the present invention. FIG. 2A is a vertical cross-sectional view illustrating a structure of a baseboard according to the second embodiment.
(B) is a longitudinal sectional view showing an attached state. FIG.
As shown in (A), in this embodiment, the core 5
A plurality of cut grooves 56 having a width H and a depth D extending in the horizontal direction are provided on an outer peripheral surface of a conical baseboard 54 having a cut end and protruding from an upper surface of the base 2. In this embodiment, as shown in FIG. 2 (B), the hanging rubber as in the conventional example and the first embodiment is not used, and shell sand 60 is filled around the baseboard 54 having the cut groove 56. Then, the core 52 is held by heat curing.

That is, first, the baseboard 54 is provided with the mounting holes 5 provided in the mold die plate 50 as in the first embodiment.
0a. Then, the cylindrical frame 42 is attached around the baseboard 54 projecting from the upper surface of the mold plate 50. The shell sand 60 is filled in the cylindrical frame 42, and is thermally cured by being externally heated. The shell sand 60 may be the same as the shell sand in which the core 52 and the baseboard 54 are formed, and sand in which a thermosetting resin is coated on the sand. Thus, a cylindrical attachment 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 baseboard 54, and the portion 62 that has entered the cut groove 56 is also thermoset integrally. The engagement between the entry portion 62 and the cut groove 56 supports the weight of the core 52 and suspends the core 52 at a predetermined height.

As described above, in the mounting structure 40 of the casting core according to the second embodiment, the core 52 can be suspended and held without using the suspension rubber, so that the production cost of the cast product is further reduced. be able to. Further, by fixing the baseboard 54 by thermosetting the shell sand 60, the displacement is less likely to occur than in the case where the shell sand 60 is attached by using the suspension rubber using the elastic force. For this reason, even if the weight of the core 52 is large, accurate positioning becomes possible, and the thickness variation of the cast product is prevented, so that a more precise cast product can be manufactured. The width H and depth D of the kerf 56 are
The size can be set to an optimum size according to the weight of the vehicle. Further, in the present embodiment, an example is shown in which the cut groove 56 as a concave portion is provided as the concave and convex portion provided in the attachment portion, but a 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 embodiments, an example has been described in which the shape of the baseboard is a conical shape with a cut end, but the size, number, arrangement, etc. of the baseboard, including the baseboard, are as described above. It is not limited to each embodiment. Also, the case has been described where the baseboard is attached to only the upper surface of the core and the core is suspended and held. However, the baseboard may be provided on another surface of the core and held. The number of claw members of the chuck mechanism, the structure of the fastening means, and the like can also be variously selected.
The structure, shape, size, material, number, arrangement, and the like of other parts of the mounting structure of the casting core are not limited to the above embodiments.

[0020]

According to the first aspect of the present invention, there is provided a mounting structure for a casting core, wherein a fastening means is provided around an elastic member for fastening the mounting portion provided on the casting core with elastic force. Therefore, even when the elastic force is reduced by repeatedly using the elastic member, the force by which the elastic member tightens the mounting portion of the core is always ensured. As a result, the core can always be accurately held at a predetermined position in the mold without increasing the casting cost due to frequent replacement of the elastic member. Obtainable.

According to the second aspect of the present invention, an uneven portion extending in a direction perpendicular to the projecting direction of the mounting portion is provided on the mounting portion of the core, and the periphery of the uneven portion is provided instead of the elastic member. Was created by attaching a thermosetting resin-hardened sand to the casting core, thereby further reducing the casting cost. Not only that, since the thermosetting resin-blended sand is thermoset and held, the core is positioned more accurately than when a hanging rubber using elastic force is used, making it extremely practical for casting. It becomes the mounting structure of the core.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional view showing Embodiment 2 of a mounting structure for a casting core.

FIG. 3 is a longitudinal sectional view showing the entire configuration of a casting mold using a conventional mounting structure for a casting core.

FIG. 4 is a plan view and a front view showing the structure of a mold plate and a core in a conventional mounting structure for a casting core.

FIG. 5 is a front view and a longitudinal sectional view showing a mounting structure of a conventional casting core.

[Explanation of symbols]

 2, 40 Casting core mounting structure 10 Tightening means (chuck mechanism) 20, 50 Mold (die plate) 20a, 50a Mounting hole 22, 52 Core 24, 54 Mounting portion (baseboard) 30 Elastic member (suspension) Rubber) 56 Uneven part (cut groove) 60 Sand mixed with thermosetting resin

Claims (2)

(57) [Claims] 1. A mounting part protruding from a casting core is passed through a mounting hole provided in a mold, and an elastic member is fitted to a protruding part of the mounting part from the mounting hole. A casting core for holding the core in a predetermined position in the mold by means of a casting core, wherein fastening means for fastening the elastic member from outside the elastic member is provided. Mounting structure. 2. A mounting part protruding from a casting core and passing through a mounting hole provided in a mold, the mounting part protruding from the mounting hole into a protruding direction of the mounting part. A mounting structure for a casting core, characterized in that an uneven portion extending in a direction perpendicular to the groove is provided, and the periphery of the uneven portion is filled with a thermosetting resin-blended sand and thermally cured.