JP5616122B2 - Core pin, core pin manufacturing method, die casting mold, and die casting mold manufacturing method - Google Patents

Description

The present invention relates to a core pin, a method for manufacturing a core pin, a die casting mold, and a method for manufacturing a die casting mold .

Generally, a core pin (core pin) fixed to a mold is used to form a hole such as a bolt hole in a die-cast product or the like. The core pin is a metal round bar, and there are a hollow one in which a cooling hole is formed along the central axis and a solid one in which no cooling hole is formed. The following Patent Document 1 discloses a core pin in which a cooling hole is formed.
The use of the core pin in which the cooling hole is formed is advantageous in that the shrinkage nest generated in the die-cast product can be moved away from the core pin position.

JP 2009-90444 A (see FIG. 1)

  However, in the core pin shown in Patent Document 1, the portion indicated by the two-dot chain line on the lower side of FIG. 7, that is, the root of the core pin 83 that faces the cavity corner 82a when attached to the die casting (casting) die 81. 7 is cooled in the same manner as the portion indicated by the alternate long and short dash line on the lower side of FIG. 7, that is, the tip of the core pin 83 (the portion indicated by the alternate long and short dashed line on the lower side of FIG. 7). The molten metal supplied (injected) into the metal (for example, molten Al alloy: molten aluminum alloy) solidifies before reaching the cavity corner 82a, and the die-cast product cannot be accurately manufactured according to the dimensions. When the die-cast product is removed from the mold 81, the die-cast product bites into the root corner 81a of the core pin 83, and becomes a die-cast product. Rack occurs or core pin 83 at the root portion corners 81a near the core pin 83 is likely to be or accidentally broken.

  Further, in the die casting mold 87 in which the cooling water passage (bottomed hole) 86 for allowing the cooling water to flow inside is directly provided, a portion indicated by a two-dot chain line on the upper side of FIG. The vicinity of the shoulder corner 87a of the die casting mold 87 facing the 88a is a portion indicated by a one-dot chain line on the upper side of FIG. 7, that is, a tip end portion of the cooling water passage 86 (a portion indicated by a one-dot chain line on the upper side of FIG. 7). The molten metal supplied (injected) into the cavity 82 (for example, molten Al alloy: molten aluminum alloy) is solidified before reaching the cavity corner 88a, and the die-cast product is When the die-cast product cannot be accurately manufactured according to the dimensions or when the die-cast product is removed from the die-cast die 87, the die-cast product is eaten by the shoulder corner 87a of the die-cast die 87. Attached, cracks may occur in the die-cast product, the shoulder portion 87b of the die casting mold 87 at the shoulder portion corners 87a near the die casting mold 87 is likely to be or accidentally broken.

  Further, the cooling hole 84 provided in the core pin 83 and the cooling water passage 86 provided in the die casting die 87 are generally drilled with a drill. The inner peripheral surface of the core pin 83 forming the die and the inner peripheral surface of the die casting die 87 forming the cooling water passage 86 are scratched (tool mark: cutting marks) by the drill blade (fine irregularities are made. ), The cooling water stays there, and the inner peripheral surface of the core pin 83 and the inner peripheral surface of the die casting die 87 are oxidized, and the inner peripheral surface of the core pin 83 and the inner peripheral surface of the die casting die 87 are oxidized. Rust may occur. In addition, if this rust progresses remarkably, cracks and cracks occur in the thickness direction of the core pin 83 and the die casting mold 87, and coolant such as water passing through the cooling holes 84 and the cooling water passage 86 leaks outside. There is a risk of release.

The present invention has been made in view of the above circumstances, and can accurately manufacture a product according to dimensions. When removing the product from the mold, the product bites into the shoulder corner of the mold or Core pin, core pin manufacturing method, die casting mold, and die casting capable of preventing the core pin from biting into the base corner and preventing the occurrence of cracks in the product removed from the mold The main object is to provide a method for producing a casting mold .

The present invention employs the following means in order to solve the above problems.
The core pin according to the present invention has an outer cylinder made of metal and a cooling hole into which cooling water flows by being housed in the outer cylinder and having a bottomed hole at the tip. An inner cylinder made of metal, and an inner cylinder made of metal that is disposed between the inner cylinder and the outer cylinder and forms an air layer in a region excluding the tip portion between the inner cylinder and the inner cylinder; a core pin used in the die casting mold which have a, the air layer is at the shoulder portions near the corners of the mold to the cavity corners and opposed when attached to the mold, and, from the mold It extends to the inside of the shoulder of the mold protruding toward the cavity, or near the root corner of the core pin facing the cavity corner when attached to the mold, and into the cavity.

The core pin according to the present invention includes an outer cylinder made of die steel, and a cooling hole that is accommodated in the outer cylinder, and has a bottomed hole having a bottom portion at the tip, and into which cooling water flows. An inner cylinder made of stainless steel, and an intermediate cylinder made of stainless steel that is disposed between the inner cylinder and the outer cylinder and forms an air layer in a region excluding the tip portion between the inner cylinder and the inner cylinder. a core pin used in the die casting mold to have a preparative, the air layer is at the shoulder portions near the corners of the mold to the cavity corners and opposed when attached to the mold, and the mold To the inside of the mold projecting toward the cavity, or near the root corner of the core pin facing the cavity corner when attached to the mold, and extending into the cavity. .

The core pin manufacturing method according to the present invention includes an outer cylinder made of metal, and a cooling that is accommodated in the outer cylinder and has a bottomed hole having a bottom portion at the tip, and into which cooling water flows. An inner cylinder made of metal in which a hole is formed, and a metal that is disposed between the inner cylinder and the outer cylinder and forms an air layer in a region excluding the tip portion between the inner cylinder and the inner cylinder. a middle tube and method of manufacturing a core pin used in the die casting mold which have a, the air layer is at the shoulder portions near the corners of the mold to the cavity corners and opposed when attached to the mold, And from the mold to the inside of the mold shoulder projecting toward the cavity, or near the root corner of the core pin facing the cavity corner when attached to the mold, to the inside of the cavity It has been extended, before A first hole having an inner diameter such that the difference from the outer diameter of the middle cylinder is 0.01 mm to 0.05 mm, and a first hole having an inner diameter where the difference from the outer diameter of the inner cylinder is 0.01 mm to 0.05 mm. 2 holes are formed along the central axis of the outer cylinder, and the first hole and the second hole are formed so that the surface roughness of the first hole and the second hole is improved. The surface is machined and inserted into the first hole until the front end surface of the middle cylinder contacts the bottom surface of the first hole, and the inner end until the front end of the inner cylinder abuts the bottom of the outer cylinder. A cylinder was inserted into the second hole, and the outer cylinder into which the inner cylinder and the middle cylinder were inserted was heated at 1000 ° C. to 1050 ° C. and then rapidly cooled.

The manufacturing method of the core pin according to the present invention includes an outer cylinder made of die steel, and is accommodated inside the outer cylinder, into which a bottomed hole having a bottom portion at the tip portion and cooling water flows. An inner cylinder made of stainless steel in which a cooling hole is formed, and a stainless steel that is disposed in a region excluding the tip portion between the inner cylinder and the outer cylinder, and forms an air layer between the inner cylinder and the inner cylinder. a core pin manufacturing method used in the die casting mold which have a a cylindrical inside made, the air layer, when attached to the die at the shoulder portions near the corners of the mold to the cavity corners facing And from the mold to the shoulder of the mold projecting toward the cavity, or near the root corner of the core pin facing the cavity corner when attached to the mold, and in the cavity Until Are the difference between the outer diameter of the first hole, and the inner cylinder having an inner diameter difference between the outer diameter in said cylinder is 0.01mm~0.05mm and a 0.01mm~0.05mm A second hole having an inner diameter is formed along the central axis of the outer cylinder, and the first hole and the second hole are formed so that the surface roughness of the first hole and the second hole is improved. The surface of the second hole is machined and inserted into the first hole until the tip surface of the middle cylinder contacts the bottom surface of the first hole, and the tip of the inner cylinder is connected to the bottom of the outer cylinder. The inner cylinder was inserted into the second hole until contacted, and the outer cylinder in which the inner cylinder and the middle cylinder were inserted was heated at 1000 ° C. to 1050 ° C. and then rapidly cooled.

According to core pin manufactured by the manufacturing method of the core pin according to the core pin and the present invention according to the present invention, space: by (air layer insulation layer), the mold (e.g., die-casting mold) cavity when attached to The vicinity of the corner of the mold facing the corner or the vicinity of the corner of the core pin facing the cavity corner when attached to the mold is not cooled in the same manner as the tip of the core pin. .
As a result, the molten metal supplied (injected) into the cavity (for example, molten aluminum alloy: molten aluminum alloy) surely reaches the cavity corner and then solidifies, resulting in a product (for example, die cast product). ) Can be accurately manufactured according to the dimensions.
Also, when removing the product from the mold, the product can be prevented from biting into the shoulder corner of the mold or the root corner of the core pin , and the product can be prevented from cracking. Further, it is possible to prevent the mold shoulder from being broken near the shoulder corner of the mold or the core pin from being broken near the root corner of the core pin .

Further, according to the core pin and core pin manufactured by the core pin manufacturing method according to the present invention according to the present invention, the inner peripheral side of the outer cylinder, rust difficult metals (e.g., stainless steel) is covered with the inner cylinder made of the cooling hole The cooling water that has flowed into the cylinder does not come into contact with the inner peripheral surface of the outer cylinder.
As a result, it is possible to prevent the inner peripheral surface of the core pin forming the cooling hole from being oxidized and rusting, and cracks and cracks are generated in the thickness direction of the core pin , and pass through the cooling hole. It is possible to prevent the cooling water from leaking outside.

Furthermore, according to the core pin manufactured by the manufacturing method of the core pin according to the core pin and the present invention according to the present invention, the inner cylinder and the outer cylinder is melted together with each other at the contact surface (bonding surface) of the inner cylinder periphery The outer cylinder and the inner peripheral surface of the outer cylinder are joined together in direct contact, and the outer cylinder is efficiently cooled by the cooling water, so that the core pin can be prevented from seizing and the shrinkage nest generated in the product can be prevented. It can be kept away from the core pin position.

Furthermore, according to the core pin manufacturing method of the present invention, since no gas is generated during the vacuum heat treatment, the core pin can be manufactured using a vacuum heat treatment furnace.

In the core pin , it is more preferable that the inner cylinder and the middle cylinder have a thickness of 0.1 mm to 0.15 mm.

According to such a core pin , since the thickness of the inner cylinder and the middle cylinder is very thin, 0.1 mm to 0.15 mm, it is not necessary to expand the inner diameter and outer diameter of the outer cylinder by the thickness of the inner cylinder, It is possible to prevent the diameter from expanding outward in the radial direction.
In addition, the inner cylinder and the middle cylinder have a very thin wall thickness of 0.1 mm to 0.15 mm, and the cooling effect by a coolant such as water that has flowed into the cooling hole has a conventional core pin that does not have the inner cylinder and the middle cylinder. Since they are maintained at substantially the same level, it is possible to improve the conventional core pin by inserting the inner cylinder into the cooling hole of the conventional core pin that does not have the inner cylinder and the middle cylinder.

According to such a core pin , the bottomed hole formed in the core pin is used as a cooling hole for supplying and cooling the cooling water, and leakage of the cooling water passing through the cooling hole is prevented. Therefore, the product yield can be improved.

In the core pin manufacturing method, it is more preferable to perform tempering after the rapid cooling.

According to such a core pin manufacturing method, residual stress generated when heated at 1000 ° C. to 1050 ° C. is removed, and a balance between appropriate hardness and tenacity according to the purpose of use is obtained and unstable. Since a stable phase can be achieved, it is possible to prevent aged deformation and cracking.

The die casting mold according to the present invention has a bottomed hole having a bottom at the tip, and a cooling water passage that is accommodated in the bottomed hole and has a bottom at the tip. An inner cylinder made of metal to be formed, and an outer cylinder made of metal which is disposed on the outer peripheral side of the inner cylinder and forms an air layer in a region excluding the tip portion between the inner cylinder and the inner cylinder. A die casting mold, wherein the air layer protrudes from the die casting mold to the cavity side in the vicinity of the shoulder corner of the die casting mold facing the cavity corner. It extends into the shoulder of the die casting die.

The die casting mold according to the present invention has a bottomed hole having a bottom at the tip, and a cooling water passage that is accommodated in the bottomed hole and has a bottom at the tip. An inner cylinder made of stainless steel to be formed, and an outer cylinder made of stainless steel that is disposed on the outer peripheral side of the inner cylinder and forms an air layer in a region excluding the tip portion between the inner cylinder and the inner cylinder. A die casting mold, wherein the air layer protrudes from the die casting mold to the cavity side in the vicinity of the shoulder corner of the die casting mold facing the cavity corner. It extends into the shoulder of the die casting die.

The die casting casting mold manufacturing method according to the present invention includes a bottomed hole having a bottom at the tip, and a cooling water housed in the bottomed hole and having a bottom at the tip. An inner cylinder made of metal that forms a use passage, and an outer cylinder made of metal that is disposed on the outer peripheral side of the inner cylinder and forms an air layer in a region excluding the tip portion between the inner cylinder and the inner cylinder. The die cast casting mold has a shoulder in the vicinity of the corner of the die casting mold facing the cavity corner and protruding from the die casting mold toward the cavity. A method for manufacturing a die-casting mold extending into a part, wherein a first hole having an inner diameter with which a difference from an outer diameter of the outer cylinder is 0.01 mm to 0.05 mm, and the inner cylinder The difference from the outer diameter of 0.01mm to 0.05mm A second hole having an inner diameter is formed along the central axis of the outer cylinder, and the first hole and the second hole are formed so that the surface roughness of the first hole and the second hole is improved. The surface of the second hole is processed and inserted into the first hole until the front end surface of the outer cylinder contacts the bottom surface of the first hole, and the front end of the inner cylinder is connected to the bottom of the outer cylinder. The inner cylinder is inserted into the second hole until it abuts, and the die casting mold in which the inner cylinder and the outer cylinder are inserted is heated at 1000 ° C. to 1050 ° C. and then rapidly cooled. I made it.

The die casting casting mold manufacturing method according to the present invention includes a bottomed hole having a bottom at the tip, and a cooling water housed in the bottomed hole and having a bottom at the tip. An inner cylinder made of stainless steel that forms a passage for the gas, and an outer cylinder made of stainless steel that is disposed on the outer peripheral side of the inner cylinder and forms an air layer in a region excluding the tip portion between the inner cylinder and the inner cylinder. The die cast casting mold has a shoulder in the vicinity of the corner of the die casting mold facing the cavity corner and protruding from the die casting mold toward the cavity. A method for manufacturing a die-casting mold extending into a part, wherein a first hole having an inner diameter with which a difference from an outer diameter of the outer cylinder is 0.01 mm to 0.05 mm, and the inner cylinder The difference with the outer diameter of 0.01mm ~ A second hole having an inner diameter of .05 mm is formed along the central axis of the outer cylinder, and the first hole and the second hole have a surface roughness that is improved. The surface of the hole and the second hole is processed and inserted into the first hole until the tip surface of the outer cylinder is in contact with the bottom surface of the first hole, and the tip of the inner cylinder is the outer cylinder. The inner cylinder is inserted into the second hole until it comes into contact with the bottom of the die casting mold, and the die casting mold into which the inner cylinder and the outer cylinder are inserted is heated at 1000 ° C. to 1050 ° C. I tried to cool it down quickly.

According to the die-casting mold according to the present invention and the die-casting mold manufactured by the method for manufacturing the die-casting mold according to the present invention, the cavity is opposed to the cavity corner by a space (air layer: heat insulating layer). The vicinity of the corner of the shoulder of the mold is not cooled in the same manner as the tip of the shoulder of the mold.
As a result, the molten metal supplied (injected) into the cavity (for example, molten Al alloy: molten aluminum alloy) surely reaches the cavity corner and then solidifies, and the die-cast product is produced according to the dimensions. It can be manufactured accurately.
Also, when removing the die-cast product from the die-casting mold, it can prevent the die-cast product from biting into the shoulder corner of the mold, and can prevent the die-cast product from cracking, It is possible to prevent the mold shoulder from being broken near the corner of the mold shoulder.

Moreover, according to the die-casting mold manufactured by the die-casting mold according to the present invention and the die-casting mold according to the present invention, the inner peripheral side of the cooling hole is made of a metal that is difficult to rust (for example, The cooling water covered with the inner cylinder made of stainless steel and flowing into the cooling hole is prevented from coming into contact with the inner peripheral surface of the die casting mold.
As a result, it is possible to prevent the inner peripheral surface of the die casting mold that forms the cooling hole from oxidizing and rusting, and cracks and cracks are generated in the thickness direction of the die casting mold. And it can prevent that the cooling water which passes a cooling hole leaks outside.

  Furthermore, according to the die-casting mold manufactured by the die-casting mold according to the present invention and the die-casting mold according to the present invention, the inner cylinder and the die-casting mold are in close contact with each other. They are melted together at the (joining surface), and the outer peripheral surface of the inner cylinder and the inner peripheral surface of the die casting mold are joined together (directly), and the die casting mold is efficiently cooled by cooling water. Therefore, the shrinkage nest generated in the die-cast product can be moved away from the position of the cooling water passage (that is, the bottomed hole).

  Furthermore, according to the method for manufacturing a die casting mold according to the present invention, since no gas is generated during the vacuum heat treatment, the die casting mold can be manufactured using a vacuum heat treatment furnace.

  In the die casting mold, it is more preferable that the inner cylinder and the outer cylinder have a thickness of 0.1 mm to 0.15 mm.

According to such a die casting mold, the thickness of the inner cylinder and the outer cylinder is as thin as 0.1 mm to 0.15 mm. Therefore, the dimension of the die casting mold is set to the thickness of the inner cylinder and the outer cylinder. There is no need to expand the size, and an increase in size can be prevented.
Further, the thickness of the inner cylinder and the outer cylinder is as thin as 0.1 mm to 0.15 mm, and the cooling effect by the coolant such as water flowing into the cooling hole is a conventional die casting that does not have the inner cylinder and the outer cylinder. Since it will be maintained at substantially the same level as the mold, the inner and outer cylinders are inserted into the cooling holes of the conventional die-casting mold without the inner and outer cylinders. The mold for use can be improved.

  In the above-mentioned die casting casting mold manufacturing method, it is more preferable to perform tempering after the rapid cooling.

  According to such a die casting casting manufacturing method, the residual stress generated when heated at 1000 ° C. to 1050 ° C. is removed, and a balance between appropriate hardness and tenacity according to the purpose of use is achieved. At the same time, since the unstable phase is stabilized, it is possible to prevent aging deformation, cracking, and the like.

According to the core pin of the present invention, the product can be accurately manufactured according to the dimensions, and when the product is removed from the mold, the product bites into the shoulder corner of the mold or goes to the root corner of the core pin . It is possible to prevent the occurrence of cracks and to prevent the occurrence of cracks in the product removed from the mold.

It is a sectional side view which shows the state which attached the core pin manufactured using the manufacturing method of the bottomed cylindrical metal member which concerns on one Embodiment of this invention to the metal mold | die for die-casting. It is sectional drawing of the core pin manufactured using the manufacturing method of the bottomed cylindrical metal member which concerns on one Embodiment of this invention. It is the figure which expanded the part enclosed with the dashed-dotted line in FIG. 2, Comprising: It is a figure which shows the manufacturing method of the bottomed cylindrical metal member which concerns on one Embodiment of this invention. It is a perspective view of the metal mold | die for die-casting which concerns on one Embodiment of this invention. It is a front view of the metal mold | die for die-casting which concerns on one Embodiment of this invention. It is sectional drawing which expands and shows the principal part of the metal mold | die for die-casting concerning one Embodiment of this invention. It is a figure for demonstrating the conventional problem.

Hereinafter, a bottomed cylindrical metal member and a manufacturing method thereof according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.
In the present embodiment, a core pin (core pin) used in a die casting mold is taken as an example of a bottomed cylindrical metal member, and after describing the use form of the core pin and the shape of the core pin, a method for manufacturing the core pin will be described.
1 is a side sectional view showing a state in which a core pin manufactured by using the manufacturing method of a bottomed cylindrical metal member according to the present embodiment is attached to a die casting die, and FIG. 2 is a bottomed bottom according to the present embodiment. Sectional drawing of the core pin manufactured using the manufacturing method of a cylindrical metal member, FIG. 3 is a figure which shows the manufacturing method of the bottomed cylindrical metal member which concerns on this embodiment.

  FIG. 1 shows a core pin 1 fixed to a die casting (molding) mold 3. The front end portion (right side in FIG. 1) 1 a side of the core pin 1 is disposed in the mold 3. A center hole is formed in the core pin 1 from the base end portion (left side in FIG. 1) along the center axis thereof, and has a bottom portion 1d (see FIG. 2) at the tip end portion 1a. A cooling hole 1c is formed. A cooling water supply pipe (inner pipe) 5 is inserted into the cooling hole 1 c along the central axis of the core pin 1.

  Cooling water is ejected from the tip 5 a of the cooling water supply pipe 5 toward the bottom 1 d of the cooling hole 1 c, that is, toward the tip 1 a of the core pin 1. The other end of the cooling water supply pipe 5 is connected to the cooling water supply pipe 7. A cooling device main body (not shown) is provided on the upstream side of the cooling water supply pipe 7. The cooling water ejected from the tip 5a of the cooling water supply pipe 5 collides with the bottom of the cooling hole 1c, reverses the flow direction, and flows in the cooling hole 1c toward the base end 1b. When the cooling water flows in this way, the core pin 1 is cooled from the inside by receiving the heat transferred through the wall portion of the core pin 1. Cooling water that flows toward the base end 1b flows into a connecting pipe (outer pipe) 9 connected to the base end 1b of the core pin 1 and is not shown in the drawing through a cooling water return pipe 11 Led to.

  As described above, by performing the die casting manufacturing process while supplying cooling water into the core pin 1, seizure of the core pin 1 can be prevented and the shrinkage nest generated in the die cast product can be moved away from the position of the core pin 1.

FIG. 2 shows the shape of the core pin 1. Note that the shape of the core pin shown in the figure is merely an example, and the present invention is not limited to this shape.
The core pin 1 includes an outer cylinder 2, an intermediate cylinder (intermediate cylinder) 4, and an inner cylinder 6. The outer cylinder 2 is made of, for example, die steel (SKD61) most widely used as a die-cast metal material, and has a large-diameter portion 12 positioned on the base end portion 1b side and a tip end portion 1a side. A small-diameter tapered portion 14 having a smaller diameter than the large-diameter portion 12, and a small-diameter linear portion 16 that is located between the large-diameter portion 12 and the small-diameter tapered portion 14 and is continuously connected to the small-diameter tapered portion 14. have.

The diameter of the large diameter portion 12 is, for example, 13 mm, and the diameter of the small diameter linear portion 16 is, for example, 4.1 mm. The diameter of the small-diameter tapered portion 14 is 4.1 mm on the base end portion 1b side, and has a tapered shape that becomes tapered as it goes to the distal end. The taper angle is set to 1 °, for example. The tip of the small diameter tapered portion 14, that is, the tip 1a of the core pin 1 is processed to have a spherical shape.
The length of the outer cylinder 2 is 250 mm. The large diameter portion 12 has a length of 25 mm, the small diameter linear portion 16 has a length of 203 mm, and the small diameter tapered portion 14 has a length of 22 mm.

  The core pin 1 is formed with a central hole as a cooling hole 1c along the central axis line from the base end portion 1b to the front end portion 1a. The tip 1a side of the cooling hole 1c does not penetrate, and a bottom 1d is provided. Thus, the cooling hole 1c is a bottomed hole. Further, from the inner peripheral surface (inner side surface) of the outer cylinder 2 located on the inner side (radial direction) of the large-diameter portion 12 and the small-diameter straight portion 16, more specifically, from the opening 1e formed on the base end portion 1b side, die casting is performed. Die-casting mold near the shoulder corner 3a (see FIG. 1) of the die-casting mold 3 facing the cavity corner 18a (see FIG. 1) when attached to the mold 3 (see FIG. 1) 3 is formed on the inner peripheral surface 2a of the small-diameter linear portion 16 located in the shoulder portion (protruding portion) 3b (see FIG. 1) of the die casting mold 3 protruding from the cavity 3 (see FIG. 1). No. 4 outer peripheral surface (outer surface), for example, an outer peripheral surface (outer surface) 4a of a pipe made of stainless steel (for example, SUS304) having a thickness of 0.1 mm to 0.15 mm (more preferably 0.1 mm) is adhered. It is attached in a state.

  Furthermore, the inner peripheral surface of the outer cylinder 2 located inside the small-diameter straight line portion 16 and the small-diameter taper portion 14, more specifically, the front end surface of the intermediate cylinder 4 (the hole 2e drilled to accommodate the intermediate cylinder 4) An inner cylinder is formed on the inner peripheral surface 2b of the small-diameter linear portion 16 and the small-diameter tapered portion 14 located on the side of the distal end portion 1a from the bottom surface 2g (see FIG. 3B) (the end surface in contact with the bottom surface 2g of FIG. 6 is attached in a state where the outer peripheral surface 6a of a pipe made of stainless steel (for example, SUS304) having a thickness of 0.1 mm to 0.15 mm (more preferably 0.1 mm) is closely attached. ing. The inner cylinder 6 extends to the opening 1e (or the vicinity of the opening 1e) formed on the base end 1b side, and an inner peripheral surface (inner side surface) of the middle cylinder 4 is between the middle cylinder 4 and the inner cylinder 6. A space (air layer: heat insulating layer) 20 is formed by 4c, the outer peripheral surface 6a of the inner cylinder 6, and the bottom surface 2g of the hole 2e (see FIG. 3B). That is, the inner side (inner peripheral side) of the outer cylinder 2 is the inner cylinder 6, and the whole or an entire portion excluding a female screw portion (not shown) to which the tip (right side in FIG. 1) of the connecting tube 9 is screwed. From the opening 1e formed on the base end 1b side, in the vicinity of the shoulder corner 3a of the die casting mold 3 facing the cavity corner 18a when attached to the die casting mold 3, and The inner peripheral surface 2a of the small-diameter linear portion 16 located in the shoulder portion 3b of the die-casting mold 3 protruding from the die-casting mold 3 toward the cavity 18 and the outer peripheral surface 6a of the inner cylinder 6 facing this A space 20 is formed between them.

An internal thread portion (not shown) is formed on the base end portion 1 b side of the cooling hole 1 c, and the distal end of the connection pipe 9 shown in FIG. 1 is screwed to the core pin 1 by the internal thread portion. .
The thickness of the small-diameter linear portion 16 is 1.0 mm from the distal end surface 4b of the intermediate cylinder 4 on the distal end portion 1a side, and 0.5 mm from the distal end surface 4b of the intermediate cylinder 4 to the proximal end portion 1b side. Is 1.0 mm at the thickest position on the base end 1b side. In addition, since the diameter is small at the tip of the small diameter taper portion 14 of the core pin 1, the thickness at this position is the thinnest.

Next, a method for manufacturing the core pin 1 will be described with reference to FIGS. 3 (a) to 3 (c).
First, as shown in FIG. 3A, the difference (clearance) from the outer diameter of the stainless steel pipe serving as the middle cylinder 4 is 0.01 mm to 0.05 mm (more preferably 0.01 mm to 0.00 mm). The difference (clearance) between the hole 2c having an inner diameter of 03 mm) and the outer diameter of the stainless steel pipe serving as the inner cylinder 6 is 0.01 mm to 0.05 mm (more preferably 0.01 mm to 0.03 mm). A hole 2d having an inner diameter is drilled (machined) along the central axis of the outer cylinder 2.
Subsequently, when drilling the holes 2c and 2d, so as to remove as much as possible the scratches (tool marks: cutting marks) attached by the drill blade, that is, the surface roughness (surface compatibility) of the holes 2c and 2d is reduced. The surfaces (inner peripheral surfaces) of the holes 2c and 2d are processed (polished) so as to be improved (smaller) to form holes 2e and 2f (see FIG. 3B).

Next, as shown in FIG. 3B, the difference (clearance) from the inner diameter of the hole 2e is 0.01 mm to 0.05 mm (more preferably) in the hole 2e processed so as to improve the surface roughness. Is inserted into the hole 2e until the tip surface 4b of the intermediate cylinder 4 contacts the bottom surface 2g of the hole 2e.
Next, as shown in FIG. 3C, the tip portion is drawn so that a spherical shape is formed at the tip portion (one end portion) in the hole 2f that has been processed to improve the surface roughness. In addition, the inner cylinder 6 having an outer diameter with which the difference (clearance) from the inner diameter of the hole 2f is 0.01 mm to 0.05 mm (more preferably 0.01 mm to 0.03 mm) is Insert into the hole 2 f until the tip is in contact with the bottom of the outer cylinder 2.
The outer cylinder 2 into which the inner cylinder 4 and the inner cylinder 6 are inserted is put into a vacuum heat treatment furnace (not shown) and heated at 1000 ° C. to 1050 ° C. for about 1 hour, and then nitrogen is blown to quench.

  Then, after putting again in a vacuum heat treatment furnace and heating at 1000 ° C. to 1050 ° C. for about 1 hour, nitrogen was blown to quench, and after placing in a vacuum heat treatment furnace three times and heating at 1000 ° C. to 1050 ° C. for about 1 hour, Blow nitrogen to quench.

According to the core pin 1 according to the present embodiment and the core pin 1 manufactured by the manufacturing method of the core pin 1 according to the present embodiment, when attached to the die casting mold 3 by the space (air layer: heat insulating layer) 20. The vicinity of the shoulder corner 3a of the die casting mold 3 facing the cavity corner 18a is not cooled in the same manner as the tip of the core pin 1.
Thereby, the molten metal supplied (injected) into the cavity 18 (for example, molten Al alloy: molten aluminum alloy) surely reaches the cavity corner 18a and then solidifies, and the die-cast product is dimensioned. Can be manufactured exactly as the street.
Further, when removing the die-cast product from the die-casting die 3, the die-cast product can be prevented from biting into the shoulder corner 3a of the die-casting die 3, and the die-cast product can be prevented from cracking. Thus, the shoulder 3b of the die casting mold 3 can be prevented from being broken near the shoulder corner 3a of the die casting mold 3.

Further, according to the core pin 1 according to the present embodiment and the core pin 1 manufactured by the manufacturing method of the core pin 1 according to the present embodiment, the inner peripheral side of the outer cylinder 2 is covered with the inner cylinder 6 made of rust-resistant stainless steel, The cooling water that has flowed into the cooling hole 1 c does not come into contact with the inner peripheral surface of the outer cylinder 2.
Thereby, it can prevent that the internal peripheral surface of the core pin 1 which forms the cooling hole 1c oxidizes, and rust generate | occur | produces, a crack and a crack generate | occur | produce in the thickness direction of the core pin 1, and a cooling hole It is possible to prevent the cooling water passing through 1c from leaking outside.

  Furthermore, according to the core pin 1 which concerns on this embodiment, and the core pin 1 manufactured by the manufacturing method of the core pin 1 which concerns on this embodiment, the inner cylinder 6 and the outer cylinder 2 melt | dissolve in the contact surface (joint surface) mutually. Then, the outer peripheral surface 6a of the inner cylinder 6 and the inner peripheral surface 2b of the outer cylinder 2 are joined in a (direct) contact state, and the outer cylinder 2 is efficiently cooled by the cooling water. Can be prevented, and the shrinkage nest generated in the die-cast product can be kept away from the core pin 1 position.

  Furthermore, according to the core pin 1 manufactured by the core pin 1 according to the present embodiment and the core pin 1 manufacturing method according to the present embodiment, the bottomed hole formed in the core pin 1 is cooled by supplying cooling water. Therefore, the leakage of the cooling water passing through the cooling hole 1c is prevented, so that the yield of the die-cast product can be improved.

  Moreover, according to the manufacturing method of the core pin 1 which concerns on this embodiment, since there is no gas generation | occurrence | production during vacuum heat processing, a core pin can be manufactured using a vacuum heat processing furnace.

  Furthermore, according to the manufacturing method of the core pin 1 which concerns on this embodiment, the residual stress produced when it heats at 1000 to 1050 degreeC is removed, and the balance with the appropriate hardness and tenacity according to a use purpose is taken. In addition, since the unstable phase is stabilized, it is possible to prevent aged deformation and cracking.

In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably.
For example, in the above-described embodiment, as illustrated in FIG. 1, the core pin 1 as a whole is described as being used as a specific example in a state where the core pin 1 is housed in the die casting mold 3. The present invention is not limited to this, and the present invention provides a core pin used in a state where a part or most of the core pin protrudes from the die casting die 81 toward the cavity 82 as shown in the lower side of FIG. Can also be applied. In this case, for example, the cooling water passage (bottom hole for cooling water) of the cylinder block (water jacket) 41 as shown in FIGS. 4 and 5 is formed by the core pin protruding from the die casting die 81 toward the cavity 82. 42 will be formed. When applied to a core pin used in a state in which a part or most of the core pin protrudes from the die casting die 81 toward the cavity 82 as shown in the lower side of FIG. When removing the die-cast product from 81, the die-cast product can be prevented from biting into the core corner of the core pin, and the die-cast product can be prevented from cracking. It is possible to prevent the core pin from being broken.

  The present invention can also be applied to a die casting mold 87 in which a cooling water passage 86 for allowing cooling water to flow inside is directly provided as shown in the upper side of FIG. In this case, as shown in FIG. 6, from the opening 61 formed on the base end portion (right end portion in FIG. 6) side, the shoulder portion of the die casting mold 62 facing the cavity corner 88a (see FIG. 7). A first portion located in the vicinity of a corner (not shown) and in a shoulder (protruding portion) (not shown) of the die casting die 62 protruding from the die casting die 62 toward the cavity 82 (see FIG. 7). On the inner peripheral surface 62a, the outer peripheral surface (outer surface) of the middle cylinder (outer cylinder) 63, for example, made of stainless steel (for example, SUS304) having a thickness of 0.1 mm to 0.15 mm (more preferably 0.1 mm). The outer peripheral surface (outer surface) 63a of the pipe is attached in close contact.

On the other hand, the first end surface of the middle cylinder 63 (the end surface in contact with the bottom surface 65 of the hole drilled to accommodate the middle cylinder 63) 63b is located on the front end portion (left end portion in FIG. 6) side, The second inner peripheral surface 62b having an inner diameter smaller than the inner peripheral surface 62a is provided on the outer peripheral surface (outer surface) of the inner cylinder 66, for example, a thickness of 0.1 mm to 0.15 mm (more preferably, 0.2 mm). 1 mm) stainless steel (for example, SUS304) pipe outer peripheral surface 66a is attached in close contact.
The inner cylinder 66 extends to the opening 61 formed on the base end side. Between the middle cylinder 63 and the inner cylinder 66, an inner peripheral surface (inner side surface) 63c of the middle cylinder 63, and the inner cylinder A space (air layer: heat insulating layer) 67 is formed by the outer peripheral surface 66a of the 66 and the bottom surface 65 of the hole. That is, the cooling water passage 68 is formed by the inner peripheral surface 66b of the inner cylinder 66, and from the opening 61 formed on the base end side, in the vicinity of the shoulder corner of the die casting mold 62 facing the cavity corner 88a. And between the 1st inner peripheral surface 62a located in the shoulder part of the die-casting die 62 which protrudes in the cavity 82 side from the die-casting die 62, and the outer peripheral surface 66a of the inner cylinder 66 facing this In this case, a space 67 is formed.
The manufacturing method of the die casting mold 62 shown in FIG. 6 is the same as the manufacturing method of the core pin 1 described with reference to FIG. 3A to FIG. .

  Furthermore, in the above-described embodiment, the middle cylinder 4 and the inner cylinder 6 have been described by taking one example made of stainless steel, but the present invention is not limited to this, and the middle cylinder 4 and The inner cylinder 6 may be made of other metals (copper, brass, die steel (SKD61), etc.).

1 Core pin (cylindrical metal member with a bottom)
1c Cooling hole 1d Bottom 2 Outer cylinder 3 Die casting mold (mold)
3a Shoulder corner 3b Shoulder 4 Middle cylinder 6 Inner cylinder 18 Cavity 18a Cavity corner 20 Air layer 62 Die casting mold (mold)
63 Outer cylinder 66 Inner cylinder 67 Air layer 68 Cooling water passage

Claims (12)

A metal outer cylinder,
An inner cylinder made of a metal that is housed in the outer cylinder and has a cooling hole into which cooling water flows and is formed into a bottomed hole having a bottom at the tip,
Is disposed between the inner cylinder and the outer cylinder to form an air layer in the region excluding the distal end portion between the inner cylinder, the die casting mold which have a a cylindrical inside made of metal A core pin used ,
Near the shoulder corner of the mold facing the cavity corner when the air layer is attached to the mold, and into the shoulder of the mold protruding from the mold toward the cavity, or in root portion near the corner of the core pin of the cavity corners and opposed when attached to the mold, and the core pin, characterized in that it is extended to the cavity. An outer cylinder made of die steel,
An inner cylinder made of stainless steel that is housed in the outer cylinder, and has a cooling hole into which cooling water flows into the bottomed hole having a bottom at the tip,
Is disposed between the inner cylinder and the outer cylinder to form an air layer in the region excluding the distal end portion between the inner cylinder, the die casting mold which have a a cylindrical inside made of stainless steel A core pin used ,
Near the shoulder corner of the mold facing the cavity corner when the air layer is attached to the mold, and into the shoulder of the mold protruding from the mold toward the cavity, or in root portion near the corner of the core pin of the cavity corners and opposed when attached to the mold, and the core pin, characterized in that it is extended to the cavity. The core pin according to claim 1 or 2, wherein a thickness of the inner cylinder and the middle cylinder is 0.1 mm to 0.15 mm. An outer cylinder made of metal, and an inner cylinder made of metal that is housed in the outer cylinder, and has a bottomed hole having a bottom portion at the tip and into which cooling water flows. When, is disposed between the inner cylinder and the outer cylinder to form an air layer in the region excluding the distal end portion between the inner cylinder, gold for die casting which have a a cylindrical inside made of metal A method of manufacturing a core pin used in a mold ,
Near the shoulder corner of the mold facing the cavity corner when the air layer is attached to the mold, and into the shoulder of the mold protruding from the mold toward the cavity, or in root portion near the corner of the core pin of the cavity corners and opposed when attached to the mold, and are extended to the cavity,
A first hole having an inner diameter that makes a difference from the outer diameter of the inner cylinder 0.01 to 0.05 mm, and an inner diameter that makes a difference from the outer diameter of the inner cylinder 0.01 to 0.05 mm Drilling a second hole along the central axis of the outer cylinder;
Processing the surface of the first hole and the second hole so that the surface roughness of the first hole and the second hole is improved,
The inner cylinder is inserted into the first hole until the front end surface of the middle cylinder contacts the bottom surface of the first hole, and the inner cylinder is moved to the second position until the front end of the inner cylinder contacts the bottom of the outer cylinder. Insert it into the hole,
A method of manufacturing a core pin , wherein the outer cylinder into which the inner cylinder and the middle cylinder are inserted is heated at 1000 ° C. to 1050 ° C. and then cooled rapidly. An outer cylinder made of die steel, and an inner cylinder made of stainless steel that is housed in the outer cylinder and has a bottomed hole having a bottom portion at the tip and into which cooling water flows . a cylindrical, is disposed between the inner cylinder and the outer cylinder to form an air layer in the region excluding the distal end portion between the inner cylinder, a die casting to have a a cylindrical inside made of stainless steel A method of manufacturing a core pin used in a mold ,
Near the shoulder corner of the mold facing the cavity corner when the air layer is attached to the mold, and into the shoulder of the mold protruding from the mold toward the cavity, or in root portion near the corner of the core pin of the cavity corners and opposed when attached to the mold, and are extended to the cavity,
A first hole having an inner diameter that makes a difference from the outer diameter of the inner cylinder 0.01 to 0.05 mm, and an inner diameter that makes a difference from the outer diameter of the inner cylinder 0.01 to 0.05 mm Drilling a second hole along the central axis of the outer cylinder;
Processing the surface of the first hole and the second hole so that the surface roughness of the first hole and the second hole is improved,
The inner cylinder is inserted into the first hole until the front end surface of the middle cylinder contacts the bottom surface of the first hole, and the inner cylinder is moved to the second position until the front end of the inner cylinder contacts the bottom of the outer cylinder. Insert it into the hole,
A method of manufacturing a core pin , wherein the outer cylinder into which the inner cylinder and the middle cylinder are inserted is heated at 1000 ° C. to 1050 ° C. and then cooled rapidly. The method of manufacturing the core pin according to claim 4 or 5, characterized in that after the quenching, and such that the tempering. A bottomed hole having a bottom at the tip, and
An inner cylinder made of metal that is housed in the bottomed hole and forms a coolant passage having a bottom at the tip,
A die casting mold having an outer cylinder made of metal that is disposed on the outer peripheral side of the inner cylinder and forms an air layer in a region excluding the tip portion between the inner cylinder,
The air layer extends in the vicinity of the shoulder corner of the die casting mold facing the cavity corner and into the shoulder of the die casting mold protruding from the die casting mold toward the cavity. A die casting mold characterized by being provided. A bottomed hole having a bottom at the tip, and
An inner cylinder made of stainless steel that is accommodated in the bottomed hole and forms a cooling water passage having a bottom portion at the tip,
A die casting mold having an outer cylinder made of stainless steel, which is disposed on the outer peripheral side of the inner cylinder and forms an air layer in a region excluding the tip portion between the inner cylinder,
The air layer extends in the vicinity of the shoulder corner of the die casting mold facing the cavity corner and into the shoulder of the die casting mold protruding from the die casting mold toward the cavity. A die casting mold characterized by being provided. The die casting mold according to claim 7 or 8 , wherein a thickness of the inner cylinder and the outer cylinder is 0.1 mm to 0.15 mm. A bottomed hole having a bottom at the tip, and an inner cylinder made of metal that is housed in the bottomed hole and forms a cooling water passage having a bottom at the tip, An outer cylinder made of metal that is disposed on the outer peripheral side of the inner cylinder and forms an air layer in a region excluding the tip portion between the inner cylinder and the air layer facing the cavity corner Manufacture of a die-casting mold extending near the shoulder corner of the die-casting mold and extending into the shoulder of the die-casting mold protruding from the die-casting mold toward the cavity A method,
A first hole having an inner diameter that makes a difference from the outer diameter of the outer cylinder 0.01 to 0.05 mm, and an inner diameter that makes a difference from the outer diameter of the inner cylinder 0.01 to 0.05 mm Drilling a second hole along the central axis of the outer cylinder;
Processing the surface of the first hole and the second hole so that the surface roughness of the first hole and the second hole is improved,
The inner cylinder is inserted into the first hole until the front end surface of the outer cylinder comes into contact with the bottom surface of the first hole, and the inner cylinder is inserted into the second cylinder until the front end of the inner cylinder contacts the bottom of the outer cylinder. Insert it into the hole,
A method for producing a die casting mold, wherein the die casting mold into which the inner cylinder and the outer cylinder are inserted is heated at 1000 ° C. to 1050 ° C. and then rapidly cooled. A bottomed hole having a bottom at the tip, and an inner cylinder made of stainless steel that is housed in the bottomed hole and forms a cooling water passage having a bottom at the tip, An outer cylinder made of stainless steel that is disposed on the outer peripheral side of the inner cylinder and forms an air layer in a region excluding the tip part between the inner cylinder and the air layer facing the cavity corner. Manufacture of a die-casting mold extending near the shoulder corner of the die-casting mold and extending into the shoulder of the die-casting mold protruding from the die-casting mold toward the cavity A method,
A first hole having an inner diameter that makes a difference from the outer diameter of the outer cylinder 0.01 to 0.05 mm, and an inner diameter that makes a difference from the outer diameter of the inner cylinder 0.01 to 0.05 mm Drilling a second hole along the central axis of the outer cylinder;
Processing the surface of the first hole and the second hole so that the surface roughness of the first hole and the second hole is improved,
The inner cylinder is inserted into the first hole until the front end surface of the outer cylinder comes into contact with the bottom surface of the first hole, and the inner cylinder is inserted into the second cylinder until the front end of the inner cylinder contacts the bottom of the outer cylinder. Insert it into the hole,
A method for producing a die casting mold, wherein the die casting mold into which the inner cylinder and the outer cylinder are inserted is heated at 1000 ° C. to 1050 ° C. and then rapidly cooled. The method for producing a die casting mold according to claim 10 or 11 , wherein tempering is performed after the rapid cooling.

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