JP2006263791A - Mold for casting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for casting, which hardly causes the positional shift of a core, and can manufacture a cast product having excellent dimensional accuracy. <P>SOLUTION: The mold 1 for casting comprises a mold body 4, and the core 5 for forming a cavity 6 by being arranged at a required position by inserting a rod shape core print 2 into a through-hole 3 of the mold body 4. The core print 2 is composed of a main rod portion 10 and one or more projections 12. The projections 12 are brought into contact with the outside surface of the mold body 4 by turning the core 5 about the axis of the main rod portion 10 by a required angle in the state that the core print 2 has been inserted into the through-hole 3. As a result, the movement of the core 5 in the axial direction of the main rod portion 10 is prevented, and the cavity 6 can be formed in the state that the core 5 has been fixed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a casting mold, and more particularly to a casting mold that is capable of producing a cast product that is less likely to cause misalignment of a core and has good dimensional accuracy.

  Conventionally, when casting a casting having a hollow portion, for example, a vehicle wheel (hereinafter simply referred to as “wheel”), a gravity casting method, a low pressure casting method, a semi-melt molding method, a semi-solid molding method, and a die casting method. A method of filling molten metal (molten metal for casting) into a cavity formed by disposing a core corresponding to a desired hollow shape in the inner space of a casting mold main body is used. It has been. Specifically, by pouring a molten casting from the runner of the cavity, filling the molten molten casting into the cavity along the outer surface of the core, and solidifying the filled molten casting A casting having a hollow part such as a wheel can be obtained.

  In addition, an outer extending member is installed on the core, and protrusions are provided at both ends of the outer extending member. Then, the core is fixed to the wheel casting space through the protruding portions, and then cast into the wheel casting space. There is a wheel casting method in which molten metal is injected and the molten metal for casting is filled to the end of the wheel casting space along the outer surface of the core (see, for example, Patent Document 1). According to the casting method described in Patent Document 1, a cast product having a hollow shape can be cast easily and at low cost.

  On the other hand, a casting apparatus for a die casting machine using a collapsible core as described above is disclosed (for example, see Patent Document 2). According to the casting device of this die casting machine, a hollow hub-shaped wheel is formed by using a collapsible core and filling the molten metal for casting poured into the cavity along the outer surface of the core. can do. In addition, since the core cast in the wheel has disintegration property, it can be easily removed by pulverizing and collapsing.

Generally, in order to arrange the core at a predetermined position in the inner space of the casting mold body, the core skirting board is fitted into a through hole (baseboard hole) formed in the casting mold. This is done by combining (inserting). However, if the casting melt is poured into the cavity with the core disposed in this way, the core floats in the internal space of the casting mold due to buoyancy, causing a misalignment of the core. Therefore, when the molten metal for casting filled in the cavity is solidified, the core does not remain in an appropriate position, and the thickness and other dimensions are strictly controlled. There was a problem that it was difficult to obtain goods.
Japanese Patent Laid-Open No. 9-1315 Japanese Patent No. 3154054

  The present invention has been made in view of the above-described problems of the prior art, and the object of the present invention is to provide a casting product that is difficult to cause misalignment of the core and can produce a cast product with good dimensional accuracy. To provide molds.

  That is, according to the present invention, a mold body having an internal space and having a through-hole formed at a predetermined location, and a bar-shaped base board formed at the tip of the mold body are fitted into the through-hole of the mold body. A casting mold having a core that is disposed at a predetermined position in the inner space of the mold body and that forms a cavity filled with a molten metal for casting. The rod-shaped main shaft portion, and one or more projecting portions projecting from the surface of the main shaft portion in a direction substantially perpendicular to the central axis of the main shaft portion on the distal end side of the main shaft portion, The core is rotated by a predetermined angle around the central axis of the main shaft portion in a state where the base plate is fitted into the through hole of the mold body, whereby the one or more protrusions of the core The central part of the core part of the core is in contact with the outer surface of the mold body Movement is restrained to the core casting mold capable of forming the cavity in a state of being fixed to a predetermined position of the inner space of the mold body is provided.

  In the present invention, the shape of the one or more projecting portions is a shape having an inclined surface that intersects with a plane perpendicular to the central axis of the main shaft portion at a predetermined angle at a location where the shape is in contact with the outer surface of the mold main body. When the core is inserted into the through hole of the mold body, the core is rotated by a predetermined angle around the central axis of the main shaft portion, so that the core is inserted into the mold body. It is preferable that the outer peripheral surface of the skirting board and the inner peripheral surface of the through hole can be in close contact with each other and seal the through hole.

  In the casting mold according to the present invention, the base plate is composed of a predetermined main shaft portion and a projecting portion, and the core is centered on the central axis of the main shaft portion in a state where the base plate is fitted into the through hole of the mold body. The protrusion is brought into contact with the outer surface of the mold body by being rotated by a predetermined angle, the movement of the core in the central axis direction is restrained, and the core is placed at a predetermined position in the inner space of the mold body. Since the cavity can be formed in a fixed state, it is difficult for the core to be displaced, and a cast product with good dimensional accuracy can be manufactured.

  Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments, and may be appropriately selected based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that design changes, improvements, etc. may be made.

  In the casting mold of the present invention, a mold body having an internal space and having a through-hole formed at a predetermined location, and a bar-shaped base board formed at the tip thereof are fitted into the through-hole of the mold body. A casting mold provided with a core that is disposed at a predetermined position in the inner space of the mold body and forms a cavity filled with the molten metal for casting, and the skirting board is a rod-shaped main shaft. And one or more projecting portions projecting in a direction substantially perpendicular to the central axis of the main shaft portion from the surface of the main shaft portion on the tip end side of the main shaft portion. When the core is rotated by a predetermined angle around the central axis of the main shaft portion while being fitted in the through hole, one or more protrusions of the core abut against the outer surface of the mold body, and the main shaft of the core The movement of the part in the central axis direction is restricted, and the core is fixed at a predetermined position in the inner space of the mold body A casting mold capable of forming a cavity. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an embodiment of a casting mold according to the present invention. FIG. 2 is a bottom view schematically showing one embodiment of the casting mold of the present invention, and shows a state where the casting mold 1 of the embodiment shown in FIG. 1 is viewed from below. is there. As shown in FIGS. 1 and 2, a casting mold 1 according to the present embodiment includes a mold body 4 having an internal space and having a through hole 3 formed at a predetermined location, and a rod-like shape formed at the tip thereof. The skirting board 2 is inserted into the through-hole 3 so that it is disposed at a predetermined position in the inner space of the mold body 4 and has a cavity 6 (with a shape corresponding to the shape of the cast product filled with the molten metal for casting. A rim molding space 15, a spoke molding space 16, and a core 5 forming a hub molding space 17). The mold body 4 may correspond to the shape of the cast product and can be divided into a plurality of partial molds as necessary. Further, the casting mold 1 shown in FIG. 1 shows a mold used for casting a wheel having a hollow hub as a preferred example, but the casting mold of the present invention is limited to this. It is not a thing.

  The skirting board 2 formed on the core 5 is substantially from the surface of the main shaft portion 10 to the central axis 11 of the main shaft portion 10 on the rod-shaped main shaft portion 10 and on the distal end side (lower side in FIG. 1) of the main shaft portion 10. It is comprised from the protrusion part 12 which protrudes in a perpendicular direction.

  When the core 5 is disposed at a predetermined position in the internal space of the mold body 4, first, the baseboard 2 is inserted into the through hole 3 formed in the mold body 4. At this time, the skirting board 2 is inserted into the through-hole 3 until the protruding portion 12 of the skirting board 2 passes through the through-hole 3 and at least a part of the protruding part 12 comes out of the mold body 4. Next, when the core 5 is rotated by a predetermined angle around the central axis 11, the projecting portion 12 of the skirting board 2 comes into contact with the outer surface 13 of the mold body. Thus, the core 5 is fixed (arranged) at a predetermined position in the inner space of the mold body 4 in a state where the movement of the main shaft portion 10 of the core 5 in the direction of the central axis 11 is stopped, and the cavity 6 Can be formed. In addition, the predetermined angle which rotates the core 5 should just be an angle used as the position which the protrusion part 12 which passed through the through-hole 3 contact | abuts on the outer surface 13 of a metal mold | die main body.

  Further, the “movement of the core in the direction of the central axis of the core” in the present invention refers to movement in both the upper and lower directions in FIG. That is, even if the molten metal for casting is poured from the pouring gate 14, the core 5 disposed in the internal space of the mold body 4 is less likely to be displaced due to the influence, mainly in the downward direction. Furthermore, even after the molten metal for casting is filled in the cavity 6, the core 5 does not float due to the influence of buoyancy, and positional displacement, mainly upward positional displacement, is unlikely to occur. Therefore, the casting mold 1 according to the present embodiment can solidify the molten casting material filled in the cavity 6 while the core 5 is disposed at an appropriate position. It is possible to obtain a cast product in which the dimensions of these are strictly controlled.

  In addition, the protrusion part 12 which comprises the base board 2 contact | abuts on the outer surface 13 of a metal mold | die main body, and has a role which arrange | positions the core 5 in an appropriate position. Here, in FIG. 1 and FIG. 2, a state in which two protrusions 12 are formed is shown, but it is sufficient that one or more protrusions are formed. However, it is preferable that two or more projecting portions are provided in order to easily act equally on the core. In addition, as shown in FIG. 1, when the tip of the skirting board 2 is observed parallel to the central axis, the protrusion 12 is disposed in a line-symmetric positional relationship with respect to the core 5. This is preferable because it works more evenly.

  FIG. 3 is a schematic view showing an example of a skirting board of a core constituting the casting mold of the present invention. In FIG. 3, an example in which the shape of the protruding portion 12 constituting the baseboard 2 is a rectangular parallelepiped is shown, but in the present invention, the shape of the protruding portion is not particularly limited, and at least a part of the protruding portion 12 is formed. Any shape that abuts on the outer surface of the mold body and prevents the movement of the core in the central axis direction of the main shaft portion may be used.

  FIG. 4 is a schematic view showing another example of the base plate of the core constituting the casting mold of the present invention. In FIG. 4, an inclined surface 30 that intersects with a plane perpendicular to the central axis 11 of the main shaft portion 1 at a predetermined angle at a position where the shape of the projecting portion 22 constituting the skirting board 2 comes into contact with the outer surface of the mold body. It is shown that it has a shape.

  Usually, a gap (play) of about 0.2 mm is formed between the skirting board and the through hole in a state where the skirting board is fitted into the through hole for reasons such as easy arrangement of the core. In some cases, casting burrs may occur in the obtained cast product when the molten metal for casting enters the gap. When a casting burr occurs in a cast product, there is a problem that it must be discarded as a defective product or a casting finishing operation must be performed to remove the casting burr.

  However, as shown in FIG. 1, the core formed with the base plate 2 having the projecting portion 22 having the shape as shown in FIG. 4 is centered on the central axis 11 with the base plate 2 inserted into the through hole 3. When the core 5 is rotated by a predetermined angle, the core 5 is pressed against the mold body 4 in the insertion direction of the skirting board 2 (downward in FIGS. 1 and 4), and the outer peripheral surface 2a of the skirting board and the inner periphery of the through hole The surface 3 a can be in close contact with at least a part of each to seal the through hole 3. Therefore, the casting mold according to the embodiment of the present invention including the core on which the base plate 2 having the projecting portion 22 having the shape as shown in FIG. 4 is formed can be easily used as a mold container. This is preferable because it can be disposed, and the occurrence of casting burrs can be prevented in the cast product, so that the production yield can be improved and the cost can be reduced.

  Next, an outline of a casting example using the casting mold of the present invention will be described. As described above, first, a casting mold 1 as shown in FIG. 1 is assembled. As the core 5 to be used, it is preferable to use a material in which a material having a disintegrating property such as sand is solidified with a resin or the like in consideration of easiness of taking out after completion of casting. When the collapsible core 5 is used, when the core 5 is rotated about the central axis 11, a portion of the projecting portion 12 that contacts the outer surface of the mold body 4 (for example, an inclination in FIG. 4). By disposing the upper end of the surface 30 to a certain extent, the core 5 can be placed in a predetermined space in the inner space of the mold body 4 in a state where the movement of the core 5 in the direction of the central axis 11 is more effectively prevented. It is preferable because it can be fixed (arranged) at a position.

  After assembling the casting mold 1, the casting melt is poured from the top 14 into the cavity 6. The poured casting molten metal flows into the hub molding space 17 corresponding to the central portion of the cavity 6 and flows into the spoke molding space 16 and the rim molding space 15 extending outward from the hub molding space 17. After all of the cavity 6 is filled with the molten casting, the molten casting is held in this state until it is solidified. After the molten casting is solidified, the mold is released and a cast product (wheel) is taken out. The core 5 may be removed after the cast product taken out with an air hammer or the like is vibrated and pulverized.

  The casting mold of the present invention is a die for a gravity casting method, a low pressure casting method, a semi-melt molding method, a semi-solid molding method, or a die casting method when casting a cast product having a hollow portion, for example, a vehicle wheel. Suitable as a mold.

It is sectional drawing which shows one Embodiment of the metal mold | die for casting of this invention. It is a bottom view which shows typically one Embodiment of the metal mold | die for casting of this invention. It is a schematic diagram which shows an example of the baseboard of the core which comprises the metal mold | die for casting of this invention. It is a schematic diagram which shows the other example of the baseboard of the core which comprises the metal mold | die for casting of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mold for casting, 2 ... Base board, 2a ... Outer peripheral surface of base board, 3 ... Through-hole, 3a ... Inner peripheral surface of through-hole, 4 ... Mold main body, 5 ... Core, 6 ... Cavity, 10 DESCRIPTION OF SYMBOLS ... Main axis part, 11 ... Center axis, 12, 22 ... Projection part, 13 ... Outer surface of die main body, 14 ... Pouring gate, 15 ... Rim molding space, 16 ... Spoke molding space, 17 ... Hub molding space, 30 ... Inclined surface .

Claims (2)

A mold main body having an internal space and having a through-hole formed at a predetermined location, and a rod-shaped skirting board formed at the tip of the mold main body are fitted into the through-hole of the mold main body, whereby the mold A casting mold provided with a core that is disposed at a predetermined position in the internal space of the main body and forms a cavity filled with a molten metal for casting,
The base plate is composed of a rod-shaped main shaft portion and one or more projecting portions projecting in a direction substantially perpendicular to the central axis of the main shaft portion from the surface of the main shaft portion on the distal end side of the main shaft portion,
The core is rotated by a predetermined angle around the central axis of the main shaft portion in a state in which the base plate of the core is fitted into the through hole of the mold body. One or more protrusions abut against the outer surface of the mold body, the movement of the core in the direction of the central axis of the main shaft portion is stopped, and the core is placed at a predetermined position in the internal space of the mold body. A casting mold capable of forming the cavity in a fixed state. The shape of the one or more projecting portions is a shape having an inclined surface that intersects with a plane perpendicular to the central axis of the main shaft portion at a predetermined angle at a position where the shape contacts the outer surface of the mold body,
The core is rotated by a predetermined angle around the central axis of the main shaft portion in a state where the base plate of the core is fitted into the through hole of the mold body, whereby the core is The base plate is pressed in the insertion direction of the base plate, and the outer peripheral surface of the base plate and the inner peripheral surface of the through hole are in close contact with each other to seal the through hole. The casting mold according to claim 1, wherein

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