JP2004268077A - Casting method and metallic mold for casting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for forming a hole as cast by using a pin for hole as cast unnecessary to draft. <P>SOLUTION: A cylindrical pin 6 for hole as cast, is disposed in a space R for product shape part to be formed as a cast product 1 in a metallic mold 5, and molten metal is filled up under state of continually rotating the pin 6 for hole as cast and waited to the solidification. After solidifying, the pin 6 for hole as cast is taken out and then, in this portion, the round hole as cast is formed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a casting method and a structure of a casting mold, and more particularly to a casting method suitable for forming a casting hole in a cast product and a structure of a casting mold (mold) used in the casting method. It is.
[0002]
[Prior art]
When casting a cast product, it is important to reduce unnecessary parts in the structure due to the so-called near-net shaping and the allowance (cutting allowance) in the secondary processing as much as possible in terms of weight reduction and cost reduction. Become. A core is generally used to form a blanked hole in a part of a cast product. In particular, in a casting method using a mold as a mold, such as an aluminum die casting method, Patent Documents 1 and 2 disclose As described above, a cast pin (also called a slide core) having a so-called draft angle is used regardless of whether it is a fixed type or a movable type.
[0003]
[Patent Document 1]
JP-A-7-299554 (FIG. 2)
[0004]
[Patent Document 2]
JP-A-10-85917 (FIG. 2)
[0005]
[Problems to be solved by the invention]
In the prior art as described above, in order to reduce the release resistance at the time of extracting the cast pin from the casting product, and to prevent the product from being damaged or underfilling called "galling", Generally, the pin itself has a tapered shape in which a gradient called a draft angle is provided. Therefore, for example, when a casting product is long and a casting hole is formed along its longitudinal direction, the tip of the casting pin is naturally smaller in diameter than the root side due to a draft angle, of course, In the part where the diameter of the cast pin is relatively small, many parts that are originally unnecessary in structure or strength remain on the product part side, and the intended purpose cannot be sufficiently achieved.
[0006]
For example, when a cast hole is formed for the purpose of weight reduction, the hole diameter becomes smaller at the tip end side of the cast pin, so that the effect of weight reduction is halved. In the case of using a passage, secondary processing such as machining is indispensable to secure a constant passage cross-sectional area, and the cost must be increased.
[0007]
The present invention has been made in view of such a problem, and the cross-sectional shape of the cast pin in the longitudinal direction is premised on preventing the occurrence of the "galling phenomenon" while securing the original pullability of the cast pin. It is an object of the present invention to provide a casting method and a casting mold capable of achieving an intended purpose by using a cast pin having a uniform or constant cross section substantially in the longitudinal direction without changing its size or size.
[0008]
[Means for Solving the Problems]
The invention according to claim 1 is characterized in that the casting is performed while moving the blanking pin which controls the forming of the blanked hole from the start of casting until the molten metal in the product shape portion solidifies.
[0009]
More specifically, as set forth in claim 2, the cast pin has a uniform cross-sectional shape in the axial direction such that a portion directly controlling the formation of the cast hole is represented by a cylindrical shape. The casting pin is continuously rotated or continuously reciprocated in the axial direction from the start of casting to the solidification of the molten metal in the product shape portion. Of course, it is also possible to use the rotation and the reciprocation of the casting pin together as needed.
[0010]
Therefore, in the inventions according to claims 1 and 2, since the cast pin is constantly rotated or reciprocated, the molten metal is filled in the product shape space facing the cast pin. Even if it does, it will be possible to prevent adhesion or sticking to the cast pin beforehand. As a result, the draft angle of the cast pin becomes unnecessary, and the cast pin and the cast hole formed with the cast pin have a uniform shape and a uniform cross section at any position. can do.
[0011]
【The invention's effect】
According to the first aspect of the present invention, the draft angle of the previously-required casting pin is eliminated, and the shape and the shape of the casting pin itself and the casting hole formed with the casting pin can be determined at any position. Since the size can be a uniform or uniform cross-sectional shape, unnecessary parts in structure or strength do not remain in the cast product as in the conventional case, and the weight can be reduced. Also, secondary processing such as machining is not required, and cost reduction can be achieved.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
1 to 3 show a preferred embodiment of the present invention. FIG. 1 shows a schematic shape of a casting to be cast, FIG. 2 shows a principle diagram of a casting method, and FIG. 3 shows a more specific casting method. Are respectively shown.
[0013]
The casting 1 shown in FIG. 1 is a so-called box-shaped one having an upper surface opened and a plurality of partitions 2, 2,... Parallel to each other inside, and includes left and right side walls 3, 3. Each of the partition walls 2, 2,... Is formed with a circular cast hole 4 of the same size at the same position.
[0014]
In order to cast such a cast product 1, as shown in FIGS. 2A and 2B, a shape corresponding to the shape of the cast hole 4 in the mold 5 in which the product shape portion space R is formed. A cast pin 6 having a cylindrical pin body 6a is arranged, the product shape space R is sealed by mold clamping, and the cast pin 6 is continuously rotated in a fixed direction. It is assumed that the space R is filled with the molten metal by a known method and solidification is waited. The casting pin 6 is still rotated during the solidification process. In other words, the casting is performed while the cast pin 6 is constantly moved.
[0015]
Here, the large-diameter portion 6b, which is a part of the cast pin 6, is exposed to the outside of the mold as shown in FIG. It is assumed that the entire casting pin 6 is removed from the mold 5 after casting with the diameter portion 6b as a supporting portion.
[0016]
Even if solidification proceeds while the casting pin 6 is rotated, the cross-sectional shape of the pin body 6 a of the casting pin 6, which is the part that should become the casting hole 4, that is, the part that directly controls the formation of the casting hole 4. Is constant, so the cast hole 4 is formed gradually in parallel with the progress of the solidification.
[0017]
FIGS. 3A and 3B show the structure of the mold 5 more concretely based on FIG. 2. The large-diameter portion 6b of the cast pin 6 is a driven gear 7, while the driven gear 7 is shown in FIGS. A piston rod 9b of a hydraulic cylinder 9, which is a direct acting actuator, is connected to a center position via a swivel joint 8, so that the casting pin 6 can be easily removed from the mold 5. That is, the casting pin 6 can move forward and backward between a retracted position P1 shown in FIG. 3A and a casting position P2 shown in FIG. 3B.
[0018]
On the other hand, a drive gear 11 that is rotationally driven by a motor (electric motor or hydraulic motor) 10 is provided outside the mold 5, and the casting pin 6 is moved forward to a casting position P2 as shown in FIG. When this is done, the drive gear 11 and the driven gear 7 are set so as to mesh with each other. Thus, the drive gear 11, the driven gear 7, and the motor 10 form a rotational drive unit 12 for the casting pin 6.
[0019]
Therefore, when the hydraulic cylinder 9 is extended from the state of FIG. 3A to insert the cast pin 6 into the mold 5 and is positioned at the casting position P2 of FIG. 11 and the driven gear 7 mesh with each other, so that the casting pin 6 can be driven to rotate.
[0020]
Next, after the mold 5 is sealed, the casting pin 6 is continuously rotated by the activation of the motor 10, and in that state, the product shape space R is filled with the molten metal as described above, and the solidification waits. . After a predetermined solidification time, the casting pin 6 is returned to the retracted position P1 as shown in FIG. 3A and the mold is opened to form the casting hole 4 as shown in FIG. The cast product 1 is taken out. By doing so, the cast pin 6 does not hinder the removal of the cast product 1 after casting.
[0021]
4 to 6 show a preferred second embodiment of the present invention. FIG. 4 shows a schematic shape of a casting to be cast, FIG. 5 shows a principle diagram of a casting method, and FIG. Each method is shown.
[0022]
The cast product 21 shown in FIG. 4 differs from that shown in FIG. 1 in that the cast holes 14 formed in the partition walls 2, 2, including the left and right side walls 3, 3, are rectangular. I have.
[0023]
In order to cast such a cast product 21, as shown in FIG. 5, a prismatic pin body 13a corresponding to the shape of the cast hole 14 is placed in the mold 5 in which the product shape space R is formed. A casting pin 13 is disposed, the product shape space R is sealed by mold clamping, and the casting pin 13 is continuously reciprocated under a predetermined stroke in the axial direction thereof. It is assumed that the subspace R is filled with a molten metal by a known method and solidified. In the process of the solidification, the cast pin 13 is still continuously reciprocated. Here, the large-diameter portion 13b, which is a part of the cast pin 13, is made to face the outside of the mold 5 as shown in FIG. 5A, and for example, the large-diameter portion 13b is reciprocally driven as a driving unit. At the same time, similarly, the entire casting pin 13 is removed from the mold 5 after casting using the large diameter portion 13b as a supporting portion.
[0024]
Even if the solidification proceeds while the cast pin 13 is reciprocated, the cross-sectional shape of the pin body 13a of the cast pin 13 at the portion that should become the cast hole 14 is constant, so that the solidification proceeds. In parallel with this, the cast hole 14 is gradually formed.
[0025]
FIG. 6 shows a more concrete structure of the mold 5 based on FIG. 5, in which the cast pin 13 is housed in the box 14 with the large-diameter portion 13b as the pressure receiving portion, while the motor 15 is The plate-shaped or drum-shaped cam 16 which is driven to rotate by means of the pressure receiving portion 13b is arranged as a cam follower. Further, an elastic body 17 such as a disc spring is disposed at the base of the pin body 13a of the cast pin 13, and a piston rod 18a of a hydraulic cylinder 18 which is a direct acting actuator is connected to the box 14, The cast pin 13 can be easily removed from the mold 5. That is, the blanking pin 13 can move forward and backward between a retracted position P1 shown in FIG. 3A and a casting position P2 shown in FIG. 3B, and the housing 14, the motor 15, the cam 16, The elastic body 17 and the like form a reciprocating drive means 19 for reciprocally driving the cast pin 13 under a predetermined stroke.
[0026]
Therefore, the hydraulic cylinder 18 is extended from the state of FIG. 6A to insert the cast pin 13 into the mold 5 to be positioned at the casting position P2 in FIG. The motor is closed and the cam 16 is continuously rotated by starting the motor 15. With the rotation of the cam 16, the cast pin 13 reciprocates in the axial direction according to the profile of the cam 16, and in this state, the product shape space R is filled with molten metal as described above. You have to wait for coagulation. If the movement in the direction in which the molding pin 13 is pushed out of the box 14 in accordance with the profile of the cam 16 is the forward movement, and the movement in the direction in which the molding pin 13 enters the box 14 is the backward movement, Is applied directly by the profile of the cam 16, while the backward movement is applied by the force of the elastic body 17. As a result, the cast pin 13 faithfully follows the rotation of the cam 16.
[0027]
After a predetermined solidification time, the casting pin 13 is returned to the retracted position P1 as shown in FIG. 6A and the mold is opened to form a casting hole 14 as shown in FIG. The cast product 21 is taken out. By doing so, the cast pin 13 does not hinder the removal of the cast product 21 after casting.
[0028]
Here, in the first and second embodiments, for the purpose of imparting non-wettability to a portion of the cast pins 6, 13 which directly controls the formation of the cast holes 4, 14, for example, to provide non-wetting properties to the pin body 6a or 13a. It is desirable to perform a treatment or a surface treatment such as a titanium coating. Since the non-wetting property referred to herein means a decrease in wettability, the molten metal is more likely to adhere to and hardly adhere to the cast pin 6 or 13. In addition to improving the durability, the inner peripheral surfaces of the as-cast holes 4, 14 that come into contact with the always-moving as-cast pins 6, 13 are adapted to smooth or smooth the surface.
[0029]
Here, in the first embodiment shown in FIGS. 1 to 3, the case where the cast pin 6 is cylindrical is used, and in the second embodiment shown in FIGS. 4 to 6, the cast pin 13 is shaped like a prism. Each of the cases is shown, assuming that the cast pin 6 is cylindrical as shown in FIGS. 2 and 3, when the contact area between the cast pin 6 and the molten metal is large, or when the cast pin 6 is durable. When high performance is required, the rotary drive system of the first embodiment and the reciprocal drive system of the second embodiment can be used together.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of a cast product having a cast hole.
2A and 2B are diagrams showing a basic principle for casting the casting product of FIG. 1, wherein FIG. 2A is a plan view, and FIG. 2B is a right side view of FIG.
FIGS. 3A and 3B are diagrams showing a schematic structure of a casting apparatus that is a more specific example of FIG. 2; FIG. 3A is a schematic explanatory view showing a state in which a cast pin is at a retracted position; FIG. FIG.
FIG. 4 is a perspective view showing another example of a cast product having a cast hole.
5A and 5B are diagrams showing a basic principle for casting the casting product of FIG. 4, wherein FIG. 5A is a plan view and FIG. 5B is a right side view of FIG. 4A.
FIGS. 6A and 6B are schematic diagrams showing a schematic structure of a casting apparatus that is a more specific example of FIG. 5; FIG. 6A is a schematic explanatory view showing a state where a cast pin is at a retracted position; FIG. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Casting product 4 ... Cast-out hole 5 ... Mold 6 ... Cast-out pin 7 ... Driven gear 9 ... Hydraulic cylinder 10 ... Motor 11 ... Drive gear 12 ... Rotation drive means 13 ... Cast-out pin 14 ... Cast-out hole 15 ... Motor 16 Cam 17 Elastic body 18 Hydraulic cylinder 19 Reciprocating drive means 21 Cast product R Product space

Claims (7)

A casting method characterized by performing casting while moving a casting pin for forming a casting hole from the start of casting until the molten metal in the product shape portion solidifies. As for the cast pin, the part directly controlling the formation of the cast hole has a uniform sectional shape in the axial direction,
2. The casting method according to claim 1, wherein the casting pin is continuously rotated or continuously reciprocated in the axial direction from the start of casting until the molten metal in the product shape portion solidifies. . 3. The casting method according to claim 2, wherein a portion of the casting pin directly controlling the formation of the casting hole is cylindrical. A casting mold used in the casting method according to claim 1,
A casting mold comprising a drive means for moving a casting pin from the start of casting until the molten metal in the product shape portion solidifies. A casting mold used in the casting method according to claim 1,
As for the cast pin, the part directly controlling the formation of the cast hole has a uniform sectional shape in the axial direction,
From the start of casting to the solidification of the molten metal in the product shape portion, the apparatus is provided with rotary driving means for constantly rotating the casting pin or reciprocating driving means for constantly reciprocating the casting pin in the axial direction. And casting mold. The casting die according to any one of claims 4 to 6, wherein the cast pin can be retracted to a position where it does not become an obstacle when taking out the product after the end of casting. The casting mold according to any one of claims 4 to 6, wherein a portion of the cast pin that directly controls the formation of the cast hole is subjected to a surface treatment for imparting non-wetting property.

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