JP3180235B2 - Special 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 special core for casting, and more particularly, to the use of a special core as a core without using a sand core which has been generally used in the past, to thereby restrict the shape of the core. The present invention relates to a special core for casting that can efficiently form a casting having a wide range of shapes without receiving it.

[0002]

2. Description of the Related Art In casting employed as a part of machine work, a non-collapsible core or a collapsible core is used to form a hollow portion or an undercut portion. I was getting it.

As the former (non-collapseable core), there is a metal core. The metal core is separated from a cast product after casting, and it is necessary to extract the metal core from the cast product after casting. For this reason, it cannot be used for anything other than those that can be directly removed or deformed, and its use range has been limited to those of a specific shape.

As the latter (collapseable core), a sand core is generally used, but it is difficult to mold,
There is a problem that not only is it easy to disintegrate and it is difficult to handle, but also it is difficult to satisfy the reciprocal condition between the pressure resistance during casting and the disintegration after casting.

[0005] In recent years, it has been proposed to obtain a cast product by using a core obtained by applying a special coating to the surface of the sand core, but there are the following problems.
The problem was not solved. (1) Coating is difficult, for example, it is necessary to form not only one layer but also a plurality of layers. Therefore, the coating is time-consuming and time-consuming, not only takes time and expense, but also takes time and cost. The initial purpose is also difficult to achieve. (2) Since it is difficult to completely remove the binder as a component of the coating layer and the sand core after casting, sand baking treatment for removing the coating layer and the binder is required. It takes time and money. (3) Since sand cores are difficult to mold, not only equipment and man-hours are required, but the molded sand cores are also fragile, difficult to handle, require man-hours, and have a low yield.
It takes time and money. (4) Since the sand core requires pressure adjustment to prevent collapse during casting, and it is difficult to completely collapse after casting, a heat treatment step, a dropout step, and a dropout inspection are required. It takes man-hours, time and money. (5) Defective products are liable to occur, such as intrusion of molten metal between core sand particles during casting, and formation of cavities in the cast product due to penetration of components of the sand core into the cast product. The yield of casting is poor, and the productivity is poor. (6) It is difficult to completely remove the core sand after casting, and it adheres to a cast product, and causes problems such as wear and breakage of the product. (7) Casting of a complicated shape or a large casting is difficult or practically impossible, so that its application range is limited. (8) When the sand of the sand core is reused after casting, since the coating layer and the binder are contained, it is difficult to completely remove the coating layer and the binder. And
It takes time and money. (9) Sand cores have drawbacks such as difficulty in molding, easily disintegrating, and difficult handling, and it is difficult to satisfy reciprocal conditions of pressure resistance during casting and disintegration after casting. It requires many steps and the yield is low, and it takes time and money.

That is, in order to obtain a casting using a conventional sand core, the following steps are required. (1) Core molding → (2) Core coating → (3) Core drying → (4) Mold formation → (5) Casting by pouring molten metal →
(6) Casting sand removal → (7) Casting sand heat treatment (sand burning) → (8) Casting sand removal inspection → (9) Casting deburring → (10) Finished product.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems by adopting the following constitution. That is, (1) By using a special core that is hard to break as a core,
The molding and handling of the core is easy, reducing man-hours, reducing time and costs, and obtaining high quality cast products. (2) By using a special core that does not use a penetrating component such as a binder, the occurrence of defects such as cavities is prevented, the occurrence of defective products is prevented, and the yield is improved and productivity is improved. Contribute to the improvement and obtain high quality cast products. (3) By using a special core having pressure resistance during casting, it is possible to avoid the occurrence of molten metal insertion during casting, avoid pressure adjustment, maintain pressure resistance (non-disintegration), and damage the cast product. And the like to prevent the occurrence of defects in castings, and to obtain castings of excellent quality. (4) The use of a special core facilitates the formation of hollow sections and undercut sections, and furthermore, by improving the core strength,
It enables casting of all shapes and sizes without being restricted by the shape and size, thereby expanding the applicable range and obtaining cast products with excellent quality. (5) By using a special core, after casting, it is integrated with the cast product, eliminating the need to remove the core from the cast product after casting, reducing man-hours, reducing time and cost, and providing high quality cast products. Get.

[0008]

According to the present invention, there is provided a casting core used for forming a hollow portion such as a hollow shape or an undercut shape inside a casting. The present invention is attained by providing a special core for casting, wherein the core for casting is formed from a metal core which is integrated with a casting after casting to be a part of the casting.

[0009]

According to the present invention, the following effects are obtained.

That is, according to the present invention, a mold is formed using a special core as a core, and casting is performed using the mold, thereby obtaining a cast product. The idea is to obtain high quality cast products efficiently by expanding the range. (1) By using a hard-to-break special core as the core,
The molding of the core is facilitated, the molding equipment is simplified, the number of steps is reduced, the time and cost are reduced, and a high quality cast product is efficiently obtained. (2) Use of a hard-to-break special core as the core makes it easy to handle because it does not break when dropped or thrown, making it easy to transport and store, and eliminates the need for pressure adjustment during casting. Is reduced, time and cost are reduced, and a cast product having excellent quality is efficiently obtained. (3) Since the special core used does not contain a penetrating component such as a binder, occurrence of defective cast products is prevented, and improvement in yield and productivity is achieved. Get products efficiently. (4) By using a special core as the core, it becomes easy to form a hollow portion or an undercut portion, and the core strength is improved. Casting becomes possible, the scope of application is expanded, and cast products with excellent quality are obtained efficiently. (5) By using a special core having pressure resistance at the time of casting, it is possible to avoid the occurrence of molten metal insertion during casting and to maintain pressure resistance (non-collapse) by avoiding pressure adjustment. It is possible to efficiently obtain a cast product having excellent quality by preventing the occurrence of defects in the cast product such as breakage of the product. (6) Since there is no need to remove the core from the cast product after casting, the number of steps is reduced, time and cost are reduced, and a cast product of excellent quality is obtained.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to the accompanying drawings, in which: FIG.

FIGS. 1 to 4 show an embodiment of a special core for casting according to the present invention.

That is, the present invention is characterized in that the core is formed from a metal core which is integrated with the casting after casting and becomes a part of the casting without using a sand core which is generally widely used as the core. It is a special core for casting.

The metal core of the present invention is required to have pressure resistance (non-collapse) during casting.

Further, the metal core is required to satisfy conditions such as generating a large amount of gas at the time of casting so as not to adversely affect the cast product.

In this embodiment, a sheet metal core will be described as an example of the metal core.

As one embodiment of the sheet metal core, a sheet metal core used in die casting will be described.

The sheet metal core 1 as the metal core is formed from a metal plate such as a steel plate.

As shown in FIG. 4, the sheet metal core 1 is formed from a metal plate such as a steel plate by plastic working such as press forming, and has a lip groove cross section (cross section C type). It is formed in the shape of.

Further, as shown in FIG. 1, the metal core 1 is disposed between the upper mold 2 and the lower mold 3 to form a mold 4.

Further, as best shown in FIG.
By disposing the metal core 1 between the upper mold 2 and the lower mold 3, a cavity 5 having a shape corresponding to the shape of the casting 6 to be molded is formed inside the mold 4. You.

As shown in FIGS. 1 and 2, a molten metal such as an aluminum molten metal is poured into the cavity 5 formed in the mold according to the material of the casting. Then, a casting 6 having a shape corresponding to the shape of the cavity 5 is formed.

Further, as best shown in FIG.
Since the casting is completed by removing the casting 6 formed as described above from the mold 4, unnecessary portions such as burrs of the casting 6 are removed, and the casting 6 as an intended finished product is removed. Is formed.

In this case, the temperature of the molten metal is considerably lower than the initial temperature (for example, about 660 ° C. in the case of an aluminum melt) before reaching the cavity 5 of the mold 4.

The sheet metal core 1 is formed of a metal plate such as a steel plate, and has a melting point of molten metal as a material of the casting 6 (for example, about 66% in the case of molten aluminum).
Since the melting point is higher than 0 ° C. (for example, about 1500 ° C. in the case of a steel plate), even if the molten metal acts, the initial shape is maintained without melting.

After the molten metal is poured into the cavity 5, the sheet metal core 1 is integrated with the casting 6 when the molten metal cools and hardens after a predetermined time.

Subsequently, as shown in FIGS. 2 and 3, the casting 6 is removed from the mold 4 to complete the casting.

Further, as best shown in FIG.
Since the casting is completed by removing the casting 6 formed as described above from the mold 4, unnecessary portions such as burrs of the casting 6 are removed, and the casting 6 as an intended finished product is removed. Is formed.

The sheet metal core 1 retains its shape at the time of casting, thereby contributing to the formation of an intended cast product 6, and after casting, a part of the cast product 6 is formed. This eliminates the need for post-processing to extract the cast product.

Then, after casting, the sheet metal core 1 is integrated with the casting 6 without casting the sheet metal core 1 from the casting to form a part of the casting 6 after casting. It is formed by removing only unnecessary portions.

Therefore, according to the special core for casting of the present invention, compared with a case where a cast product is obtained by casting using a sand core which is generally widely used as a conventional core, the binder By not containing a penetrating component such as, etc., and covering the inner wall surface of the hollow part (inner wall surface of the casting) such as a hollow shape or an undercut shape with a sheet metal core, the insertion of the molten metal and the cavity in the casting The occurrence of defective products such as the occurrence of castings is prevented,
By improving the yield and the productivity, it is possible to efficiently obtain a casting having excellent appearance quality and functional quality and improved quality.

Thus, in the case of performing the casting using the special core of the present invention, in the case of performing the die casting as the above-described embodiment, the following five steps are completed. (1) Core molding → (2) Mold formation → (3) Casting by pouring molten metal → (4) Deburring of cast product → (5) Finished product.

Therefore, when the special core for casting according to the present invention is used, when performing die casting, which is one of the casting methods, the conventional method requires the following 10 steps. , 5 steps are omitted, only half the steps are required, the process can be greatly shortened, and the use of sand without using sheet metal on the surface of the material can greatly reduce the occurrence of leaks and voids. Become.

That is, the conventional method using a sand core is as follows.
It is as follows. (1) Core molding → (2) Core coating → (3) Core drying → (4) Mold formation → (5) Casting by pouring molten metal →
(6) Casting heat treatment (sand burning) → (7) Casting sand removal → (8) Casting sand removal inspection → (9) Casting deburring → (10) Finished product.

Next, FIG. 5 shows a second embodiment of the special core used in the present invention.
Although the sheet metal core 1 of the above embodiment is integrally formed by plastic working such as press forming, it is formed into a shape divided into two by plastic working such as press forming.

This is different from the case where the sheet metal core 1 of the above embodiment is formed integrally from the viewpoint of workability and ease of handling. The plastic workability such as press forming of the core 1 is further improved.

The other flange portion is sandwiched between the one flange portion, the pressure resistance (non-collapse property) during casting is maintained, and the occurrence of problems such as breakage of the cast product 6 is prevented. There is an effect that a cast product 6 having excellent quality can be obtained.

The special core for casting of the present invention is not limited to the above-described embodiment, but can be applied to various shapes, and can improve the quality of a cast product. The present invention is not limited to the examples, and many modifications are possible.

The special core for casting of the present invention is not limited to the one formed by the casting method of the above embodiment, but may be obtained by adding a specific step to further improve the quality of a cast product. The present invention is not limited to the cast product using the special core of the above-described embodiment, and many modified examples are conceivable.

Further, the sheet metal core as the metal core of the present invention is not limited as long as it has pressure resistance at the time of casting and does not exert a bad influence on the cast product such as generation of a large amount of gas at the time of casting. The following core materials satisfy the above conditions.

That is, examples of the material of the sheet metal core satisfying the above conditions include a steel plate and an iron plate, which have a much higher melting point than aluminum and zinc which are widely used for die casting. A cast product that satisfies both conditions and sufficiently satisfies the initial purpose can be obtained.

As the metal plate as a material of the sheet metal core 1 satisfying the above-mentioned conditions, a plate made of a metal different from that of the above-mentioned cast product, as well as the same metal as the cast product (ie, the same metal as the molten metal) For example, aluminum or zinc, which is a material widely used for die casting, can be used. A cast product satisfying any of the above conditions and satisfying the initial purpose can be obtained. In this case, the temperature of the molten metal is considerably lower than the initial temperature (for example, about 660 ° C. in the case of molten aluminum) before reaching the cavity 5 of the mold 4.

Therefore, even if the metal core 1 is a plate material (for example, an aluminum plate) made of the same metal as the cast product (namely, the same metal as the molten metal), it does not melt even if the molten metal acts. Retain the initial shape. Then, after pouring the molten metal into the hollow portion 5, the metal core 1 is integrated with the casting 6 when the molten metal cools and hardens after a predetermined time.

The metal core of the present invention is not limited to the sheet metal core of the above embodiment, but may be a metal core other than a plate-shaped metal core.
As long as it does not adversely affect the cast product such as generating a large amount of gas at the time of casting, metals of shapes and materials other than the above embodiment can be used, and the same effects as those of the above embodiment can be obtained. Obtainable.

Further, the case where the sheet metal core of the above embodiment is used for die casting as one of the casting methods has been described. However, the special core of the present invention is not limited to the die casting, but may be a sand mold. It can be applied to casting, mold gravity casting, low pressure casting, precision casting, and other casting methods, and can be used in such casting methods to contribute to obtaining the desired casting. Of course, the same effect as in the above embodiment can be obtained.

Further, the special core for casting of the present invention is not limited to the case where the sheet metal core or the like of the above embodiment is used in the above-mentioned casting method, and many variations are conceivable.

Next, the operation of the special casting core according to this embodiment will be described.

As described above, the present invention uses a metal core as the core to improve productivity and expand the applicable range, and to obtain a cast product having excellent quality. There are the following effects. (1) By using a special core that is hard to break as a core,
The molding of the core is facilitated, the molding equipment is simplified, the number of steps is reduced, time and cost are reduced, and a cast product having excellent quality can be efficiently obtained. (2) Use of a hard-to-break special core as the core makes it easy to handle because it does not break when dropped or thrown, making it easy to transport and store, and eliminates the need for pressure adjustment during casting. , And time and cost can be reduced, and a cast product having excellent quality can be obtained efficiently. (3) Since the special core used does not contain a penetrating component such as a binder, occurrence of defective cast products is prevented, and improvement in yield and productivity is achieved. Goods can be obtained efficiently. (4) By using a special core as the core, it becomes easy to form a hollow portion or an undercut portion, and the core strength is improved. Casting can be performed, and the applicable range can be expanded, so that a cast product excellent in quality can be efficiently obtained. (5) By using a special core having pressure resistance at the time of casting, it is possible to avoid the occurrence of molten metal insertion during casting and to maintain pressure resistance (non-collapse) by avoiding pressure adjustment. It is possible to prevent the occurrence of defects in the cast product such as breakage of the product, and to efficiently obtain a cast product having excellent quality. (6) Since the casting and the metal core are integrated after casting to make the metal core a part of the casting, it is not necessary to extract the metal core from the casting after casting. Expenses can be reduced and a cast product of excellent quality can be obtained.

It should be noted that the metal core of the present invention is not limited to the above-described embodiments, and many variations are conceivable.

[0050]

As described above, according to the present invention, by using a metal core as a core, it is possible to improve the productivity and expand the applicable range and to obtain a cast product having excellent quality. This is an idea and has the following excellent effects. (1) By using a special core that is hard to break as a core,
There are advantages that the molding of the core becomes easy, the molding equipment is simplified, the number of steps is reduced, time and cost are reduced, and a high quality cast product can be efficiently obtained. (2) Use of a hard-to-break special core as the core makes it easy to handle because it does not break when dropped or thrown, making it easy to transport and store, and eliminates the need for pressure adjustment during casting. This is advantageous in that the cost can be reduced, time and cost can be reduced, and a cast product excellent in quality can be efficiently obtained. (3) Since the special core used does not contain a penetrating component such as a binder, occurrence of defective cast products is prevented, and improvement in yield and productivity is achieved. There is an advantage that products can be obtained efficiently. (4) By using a special core as the core, it becomes easy to form a hollow portion or an undercut portion, and the core strength is improved. This has the advantage that casting with high quality can be obtained, the application range can be expanded, and a casting having excellent quality can be obtained efficiently. (5) By using a special core having pressure resistance at the time of casting, it is possible to avoid the occurrence of molten metal insertion during casting and to maintain pressure resistance (non-collapse) by avoiding pressure adjustment. There is an advantage that a cast product having excellent quality can be efficiently obtained by preventing occurrence of a trouble of the cast product such as breakage of the product. (6) The casting and the metal core are integrated after casting to make the metal core a part of the casting, and there is no need to remove the metal core from the casting after casting. And there is an advantage that a cast product having excellent quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a mold using a sheet metal core which is a metal core among special cores for casting according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a case in which a casting is formed by pouring a molten metal into a mold using a sheet metal core that is a metal core among the special cores for casting according to the first embodiment of the present invention. It is.

FIG. 3 is a cross-sectional view showing a cast product formed by a mold using a sheet metal core which is a metal core among the special cores for casting according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a sheet metal core which is a metal core among the special cores for casting according to the first embodiment of the present invention.

FIG. 5 is a sectional view showing a second embodiment of the special core for casting. Reference Signs List 1 sheet metal core (metal core) (special core) (non-sand core) 2 upper mold 3 lower mold 4 mold 5 cavity 6 casting

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-142662 (JP, A) JP-A-63-260657 (JP, A) JP-B-51-41971 (JP, B2) JP-B-58- 12099 (JP, B2) JP 3-37815 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) B22C 1/00 B22C 9/10 B22D 19/00

Claims (2)

(57) [Claims] 1. A casting core formed by using a metal core to be integrated with a casting after casting to form a part of the casting, wherein the casting core is formed of a metal having a melting point higher than that of a molten metal. It is formed from a sheet metal core formed in a divided manner, and the flange portion of one core has a flange portion of the other core.
By pinching the part, the pressure resistance (non-
A special core for casting characterized by improved disintegration) . 2. Covering the inner wall surface (inner wall surface of a cast product) of a hollow portion such as a hollow shape or an undercut shape, thereby preventing defective products such as insertion of a molten metal and occurrence of a cavity, thereby preventing the occurrence of a defective product. part of being used to form the interior of the casting, it is characterized in claim 1 Symbol placement casting special core of.