Casting method and casting mold

Abstract

A casting method and casting mold able to easily produce a casting having an island and connecting portion at a high quality. A casting (1) having a body (11), a opening (12) provided so as to pass through the body, an island (121) arranged separated from the body in the opening, and a connecting portion (22) joining the island and body is cast using a casting mold (2). The casting mold is provided with a body gate (311) connected to a body cavity for forming the body and a opening gate (321) connected to an island/connecting portion cavity (32) for forming the island and the connecting portion. The body gate and opening gate are connected to a runner (33) through body pin gates (312) and opening pin gates (322).

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a casting method and a casting mold for casting a product having a body, a opening provided so as to pass through that body, an island arranged inside the opening away from the body, and a connecting portion joining the island and the body, in particular a casting method and mold for casting a product with thicknesses of the body, island, and connecting portion of 1.5 to 4 mm. Note that here, the term “mold” is used in a sense including both “molds” and “dies”.

[0003] 2. Description of the Related Art

[0004] In the past, for example in the die casting method for casting a product used for various parts, a cavity having the same shape as the product has been formed between a pair of molds and a melt of metal has been filled in the cavity to cast the product.

[0005] In this die casting method, a gate serving as an inlet for the melt in the cavity and a runner for guiding the melt poured from a pouring portion into the gate are provided between the pair of molds. Further, the melt is poured into a sleeve at the pouring portion and the melt injected to the runner by a plunger to fill the melt in the cavity from the runner through the gate.

[0006] With the conventional casting method, however, it was difficult to produce a casting having a complicated shape or a thin casting. For example, it was difficult to cast a part having a opening provided so as to pass through the body and having inside that opening an island arranged separated from the body and a connection portion joining the island and body.

[0007] That is, in a casting having such an island and connecting portion, the melt flowing from the runner to the body has to flow to the island through the connecting portion. It is however not easy to feed melt from the body to the connecting portion and island. In many cases, the melt is not sufficiently filled there—resulting in casting defects.

[0008] The problem of casting defects can be said to occur not only in the die casting method, but also general casting methods. Therefore, a casting method able to produce a casting having an island and connecting portion easily and with a high quality has been desired.

SUMMARY OF THE INVENTION

[0009] An object of the present invention is to provide a casting method and casting mold able to easily produce a casting having an island and connecting portion in a high quality state.

[0010] According to a first aspect of the present invention, there is provided a casting method for casting a product having a body, a opening provided so as to pass through the body, an island provided separated from the body in the opening, and a connecting portion joining the island and body using a mold having a cavity corresponding to the shape of the product, the mold being provided with a body gate connected to a body cavity for forming the body in the cavity and a opening gate connected to an island/connecting portion cavity for forming the island and connecting portion in the opening in the cavity; the body gate and opening gate being connected to a runner for introducing a melt into them; and the melt fed into the runner being filled in the cavity through the body gate and the opening gate.

[0011] That is, the present invention provides a casting method for a product having a body forming the outer shape of the product as a whole and an island and connecting portion formed in the opening passing through the body.

[0012] Further, in the present invention, use is made of a mold providing the body gate and opening gate at a body cavity and island/connecting portion cavity and connecting these gates to a runner.

[0013] Therefore, it is possible to easily produce a casting having a complicated shape in a state with no casting defects.

[0014] That is, the melt introduced into the runner is divided between the body gate and the opening gate. Further, the melt starts to be filled in the body cavity from the body gate, while the melt starts to be filled in the island/connecting portion cavity from the opening gate. That is, melt is directly sent through the gates to the body cavity and the island/connecting portion cavity.

[0015] Accordingly, it is possible to prevent melt from being supplied later to one cavity than the other cavity and possible to directly and quickly fill melt to both cavities. For this reason, it is possible to prevent the delay of supply of melt and the occurrence of casting defects.

[0016] In this way, it is possible to match as much as possible the ease of filling of melt between the body cavity and the island/connecting portion cavity even when producing a casting having an island and connecting portion.

[0017] Accordingly, it is possible to easily produce a high quality casting with almost no problem of casting defects even in a casting having an island and connecting portion.

[0018] In the second aspect of the invention, the mold may have a three-part structure of a fixed mold, intermediate mold, and movable mold. In this case, the fixed mold and the intermediate mold are provided between them with the runner; the intermediate mold and movable mold are provided between them with the cavity, the body gate, and the opening gate; the intermediate mold is provided with a body pin gate connecting the runner and the body gate and a opening pin gate connecting the runner and the opening gate; and the melt sent into the runner is filled in the cavity through the body pin gate and body gate and through the opening pin gate and opening gate.

[0019] In this case, the runner, pin gates, gates, and cavity may be arranged three-dimensionally. Therefore, it is possible to easily secure a path of supply of the melt from the runner to the body gate and opening gate.

[0020] Further, after filling the melt into the cavity and forming the casting, it is possible to move the fixed mold, intermediate mold, and movable mold relative to each other so as to release the castings formed in the cavity, pin gates, and runner from the fixed mold, intermediate mold, and movable mold and enable them to be easily removed.

[0021] Further, the method may comprise filling the melt, then moving the intermediate mold and movable mold to separate the fixed mold and the intermediate mold; moving the movable mold to separate the intermediate mold and movable mold, cutting the runner casting formed in the runner from pin gate castings formed in the body pin gate and the opening pin gate, and releasing the pin gate castings from the intermediate mold; then releasing the casting in the state from the mold with the pin gate castings attached from the movable mold.

[0022] In this case, after forming the casting, it is possible to successively move the fixed mold, intermediate mold, and movable mold to enable the formed casting to be easily released from the mold and taken out.

[0023] The intermediate mold and the movable mold may have between them a balance runner provided at least at part of the section between the body pin gate and the body gate and at least at part of the section between the opening pin gate and the opening gate. At least part of the melt may be supplied from the body pin gate through the balance runner to the body gate and from the opening pin gate through the balance runner to the opening gate.

[0024] By providing this balance runner, it is possible to adjust the rates of filling the melt between adjoining body gates or between adjoining opening gates and send the melt under pressure as equally as possible to all parts of the body cavity or island/connecting portion cavity.

[0025] The casting may for example be a front end panel for an automobile and have a body having a surround, a opening formed inside the surround, a part mount as an island arranged in the opening, and stays supporting the part mount as the connecting portion.

[0026] In this case, it is possible to cast the island and connecting portion of the front end panel without casting defects. Further, the front end panel can be formed integrally with the body, part mount, and stays by a single casting operation. Therefore, the casting cost can be reduced.

[0027] Here, the part mount may mount a motor, fan, or pulley. In this case, it is possible to produce a high quality front end panel using this part mount as the mount for a motor, fan, or pulley.

[0028] According to a second aspect of the present invention, there is provided a casting mold for casting a product having a body, a opening provided so as to pass through the body, an island provided separated from the body in the opening, and a connecting portion joining the island and body, the mold having a three-part structure of a fixed mold, intermediate mold, and movable mold; the intermediate mold and movable mold being provided between them with a cavity having a body cavity for forming the body and an island/connecting portion cavity for forming the island and the connecting portion in the opening, a body gate connected to the body cavity, and a opening cavity connected to the island/connecting portion cavity; the fixed mold and the intermediate mold being provided between them with a runner for introducing melt into the body gate and the opening gate; the intermediate mold being provided with a body pin gate connecting the runner and the body gate and a opening pin gate connecting the runner and the opening gate; and the melt sent into the runner being filled in the cavity through the body pin gate and body gate and through the opening pin gate and opening gate.

[0029] The structure of the casting mold of the present invention does not form the cavity, gates, and runner at the interface of a pair of molds as in the past, but forms them at other portions than the interface for a three-dimensional arrangement.

[0030] Due to this, it is possible to form the opening gate directly in the island/connecting portion cavity where the melt has difficulty flowing to and introduce the melt from the opening gate directly to the island/connecting portion cavity. Further, to introduce melt directly to the body cavity and island/connecting portion cavity, it is also possible to provide the above body pin gate and opening pin gate, respectively.

[0031] This structure of the mold can be realized by a three-part structure of a fixed mold, intermediate mold, and movable mold as explained above.

[0032] That is, the runner is provided between the fixed mold and the intermediate mold, and the cavity, body gate, and opening gate are provided between the intermediate mold and movable mold. Further, the intermediate mold is provided with the body pin gate for connecting the body cavity and body gate and the opening pin gate for connecting the island/connecting portion cavity and the opening gate.

[0033] Due to this, it is possible to supply melt directly to the body cavity and the island/connecting portion cavity and possible to easily release the product etc. from the mold after the casting as explained above.

[0034] For this reason, if using the casting mold of the present invention, it is possible to realize a casting method which enables the formation of a casting in a high quality state free from casting defects even for a casting having the island and connecting portion and which enables the casting to be easily taken out from the casting mold after being shaped.

[0035] A plurality of at least one of the body gate and the opening gate may be provided. In this case, in the body cavity or island/connecting portion cavity, it is possible to reduce as much as possible the imbalance in distance from the body gates or opening gates to the portions for filling of the melt. Therefore, it is possible to fill the melt with a good balance in the cavities.

[0036] Here, the body pin gate and/or the opening pin gate may be reversely tapered to expand in channel area from the fixed mold toward the movable mold or from the movable mold toward the fixed mold. In this case, it is possible to easily cut the pin gate castings formed in the body pin gate and opening pin gate at the constricted part of the smallest channel area in the body pin gate or opening pin gate.

[0037] When forming the pin gates reversely tapered so as to expand in channel area from the fixed mold toward the movable mold, after forming the casting in the cavity, when moving the intermediate mold and movable mold with respect to the fixed mold, the pin gate castings stick to the pin gates and therefore can be easily cut.

[0038] When making the movable mold move from the intermediate mold, the pin gate castings can be easily released from the intermediate mold along the reversely tapered inclined surfaces.

[0039] On the other hand, when forming the pin gates reversely tapered to expand in channel area from the movable mold toward the fixed mold, after forming the casting in the cavity, when moving the movable mold with respect to the intermediate mold, the pin gate castings stick to the pin gates and therefore can be easily cut.

[0040] When making the intermediate mold move from the fixed mold, the pin gate castings can be easily released from the intermediate mold along the reversely tapered inclined surfaces.

[0041] The body pin gate and/or the opening pin gate may be provided at an cavity insert detachably inserted in an cavity insert setting hole provided in the intermediate mold. In this case, by preparing a plurality of types of cavity insert of different pin gate diameters and switching between them, it is possible to adjust the rates of flow of melt sent under pressure to the pin gates. By adjusting the inside diameter of the cavity insert, it is possible to easily change and adjust the inclination angle of the inclined surface of the reverse taper. Even if the pin gates become worn, maintenance becomes easy by exchanging only the cavity inserts. The cavity inserts can be produced divided into several parts.

[0042] The draft of at least part of an inner wall of the cavity at the movable mold side may be set to not more than 1°. In this case, when moving the movable mold from the intermediate mold, it is possible to move it while leaving the casting formed in the cavity at the inside wall of the cavity at the movable mold side by the frictional resistance between the casting and inside wall of the cavity at the movable mold side. If the draft of all portions in the cavity exceeds 1°, the frictional resistance between the casting and the inside wall of the cavity at the movable mold side is liable not to be sufficiently obtained.

[0043] The movable mold may be provided with a plurality of ejector pins for pushing out the casting formed in the cavity from the cavity. In this case, after forming the casting in the cavity, the casting can be pushed out and easily removed by moving the ejector pins in the direction of the intermediate mold.

[0044] The ejector pins may be provided to abut against the casting near body pin gates and/or opening pin gates. In this case, when releasing the casting from the casting mold, it is possible to stably and smoothly release the casting.

[0045] The intermediate mold and the movable mold may have between them a balance runner provided at least at part of the section between the body pin gates and the body gate and at least at part of the section between the opening pin gates and the opening gate. By providing this balance runner, it is possible to adjust the rates of filling of the melt between adjoining body gates or adjoining opening gates and send the melt under pressure as uniformly as possible to all parts of the body cavity or all parts of the island/connecting portion cavity.

[0046] When a balance runner is provided in the above way, the movable mold may be provided with a plurality of ejector pins for pushing out the casting formed in the cavity from the cavity and the ejector pins may be provided to abut against the balance runner near the positions of the body pin gates connected to the balance runner. In this case, when releasing the casting from the casting mold, it is possible to stably and smoothly release the casting.

[0047] A projection projecting out in the direction of the intermediate mold may be provided near a joining portion of a body pin gate and/or opening pin gate and the balance runner. In this case, after forming the casting in the cavity, when moving the movable mold with respect to the intermediate mold, it is possible to cause frictional resistance between the projection and the casting portion formed around it. Further, due to this frictional resistance, it is possible to easily move the movable mold in the state with the casting left in the movable mold.

[0048] An end part formed at the movable mold at the body pin gate and/or opening pin gate may be provided with a distributer projecting out toward an inlet of the body pin gate and/or the opening pin gate. In this case, when changing the direction of flow of the melt passing through the body pin gate or the opening pin gate, it is possible to cause the melt to easily strike the distributer and smoothly change the direction.

[0049] After forming the casting in the cavity, when moving the movable mold with respect to the intermediate mold, it is possible to cause frictional resistance between the distributer and the casting portion formed around it. Further, due to the frictional resistance, it is possible to easily move the movable mold in the state with the casting left in the movable mold.

[0050] After the melt finishes being filled, due to the formation of the distributer, the contact area between the distributer and the casting portion formed around it becomes larger. Therefore, it is possible to rapidly cool the casting portion formed around the distributer and possible to move the movable mold to rapidly remove the casting formed in the cavity.

[0051] The distributer may be shaped with a draft of at least part of not more than 1°. In this case, when moving the movable mold from the intermediate mold, it is possible to easily cause frictional resistance between the distributer and the casting portion formed around it to more easily move the movable mold in the state where the casting is left in the movable mold.

[0052] The portion where a body pin gate and/or opening pin gate connects with the runner may be provided with a constricted part reduced in channel area. In this case, when moving the movable mold with respect to the intermediate mold, it is possible to cause stress concentration at the constricted part and therefore easily cut the body pin gate or opening pin gate provided with the constricted part.

[0053] The runner may be branched into a body runner for introducing the melt into the body pin gate and a opening runner for introducing the melt into the opening pin gate. In this case, at the time of feeding the melt to the runner under pressure, it is possible to branch the flow path to the body cavity and the flow path to the island/connecting portion cavity, so it is possible to fill the melt in these cavities with a much better balance.

[0054] The body runner and opening runner may be adjusted in inside diameter so that the rates of filling the melt in them become substantially equal. In this case, it is possible to easily make the ease of filling the melt between the body cavity and the island/connecting portion cavity match and possible to produce a casting of a much higher quality.

[0055] The opening runner may have a shape similar to the shape of the island. That is, if the island is ring shaped, the opening runner may be provided in a circular curved shape matching with this. In this case, it is possible to easily provide the opening gate at the portion of the opening runner corresponding to the shape of the island and possible to fill the melt with a good balance in all parts of the island/connecting portion cavity.

[0056] The cavity may be connected to a pressure reducing means for reducing the pressure in the cavity. In this case, when filling the melt in the cavity, it is possible to positively reduce the pressure in the cavity and therefore possible to easily fill the melt at the different parts of the cavity.

[0057] The casting may be a front end panel for an automobile and have a body having a surround, a opening formed inside the surround, a part mount as an island arranged in the opening, and stays supporting the part mount as the connecting portion.

[0058] In this case, it is possible to cast the island and connecting portion of the front end panel without casting defects and thereby possible to produce a high quality front end panel. Further, the front end panel can be formed with the body, part mount, and stays by a single casting operation. Therefore, the casting cost can be reduced.

[0059] The part mount may mount a motor, fan, or pulley. In this case, it is possible to produce a high quality front end panel using the part mount to mount a motor, fan, pulley, or other part.

[0060] According to a third aspect of the present invention, there is provided a casting method for casting a product having a body, a opening provided so as to pass through the body, an island provided separated from the body in the opening, and a connecting portion joining the island and body using a mold having a cavity corresponding to the shape of the product, the mold having a body cavity for forming the body in the cavity, an island/connecting portion cavity for forming the island and the connecting portion in the opening in the cavity, and a opening gate connected to the island/connecting portion cavity, the opening gate being connected to a runner introducing melt into it; the melt fed into the runner being filled in the cavity through the opening gate.

[0061] The melt fed into the runner starts to be filled in the island/connecting portion cavity from the opening gate. Further, the melt flowing into the island/connecting portion cavity then flows into the body cavity and fills the cavity as a whole.

[0062] In this way, since the melt is introduced into the cavity through the opening gate, it is possible to prevent the problems of casting defects etc. in the island/connecting portion cavity and possible to produce a high quality casting.

[0063] According to a fourth aspect of the present invention, there is provided a casting mold for casting a product having a body, a opening provided so as to pass through the body, an island provided separated from the body in the opening, and a connecting portion joining the island and body, the mold having a three-part structure of a fixed mold, intermediate mold, and movable mold; the intermediate mold and movable mold being provided between them with a cavity having a body cavity for forming the body and an island/connecting portion cavity for forming the island and the connecting portion in the opening and a opening cavity connected to the island/connecting portion cavity; the fixed mold and the intermediate mold being provided between them with a runner for introducing melt into the opening gate; the intermediate mold being provided with a opening pin gate connecting the runner and the opening gate; and the melt sent into the runner being filled in the cavity through the opening pin gate and opening gate.

[0064] By using this casting mold, it is possible to easily introduce a melt into the cavity through the opening gate. Due to this, if using this casting mold, it is possible to easily produce a high quality casting free of defects in the opening.

BRIEF DESCRIPTION OF THE DRAWINGS

[0065] These and other objects and features of the present invention will become clearer from the following description of the preferred embodiments given with reference to the attached drawings, in which:

[0066] FIG. 1 is a perspective view of the overall configuration of a casting in the present embodiment;

[0067] FIG. 2 is a partial perspective view of the state where part of the casting of the present embodiment and the casting portion formed at a runner at the time of casting are connected;

[0068] FIG. 3 is a sectional view of the structure of a casting mold in the present embodiment;

[0069] FIG. 4 is a sectional view of the state of the casting mold in the present embodiment being filled with a molten metal;

[0070] FIG. 5 is a sectional view of the opened state of a fixed mold and intermediate mold of the casting mold in the present invention;

[0071] FIG. 6 is a sectional view of the opened state of an intermediate mold and movable mold of the casting mold in the present embodiment;

[0072] FIG. 7 is a sectional view of the state of separation of the product from the cavity in the present embodiment;

[0073] FIG. 8 is a partial sectional view of the structure of a body pin gate and opening pin gate in the present embodiment;

[0074] FIG. 9 is a partial sectional view of a constricted parts of a body pin gate and opening pin gate in the present embodiment;

[0075] FIG. 10 is a partial sectional view of end part of a body pin gate and opening pin gate in the present embodiment; and

[0076] FIG. 11 is a partial sectional view of a casting mold in the case of forming a body pin gate and opening pin gate in the present embodiment reversely tapered to expand in channel area from the movable mold toward the fixed mold.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0077] Below, a preferred embodiment of the present invention will be described with reference to the drawings.

[0078] As shown in FIG. 1 and FIG. 2, in the casting method of this embodiment, a casting 1 having a body 11, openings 12 provided so as to pass through the body 11, islands 121 arranged separated from the body 11 in the openings 12, and connecting portions joining the islands 121 and the body 11 is produced. This casting 1 is produced, as explained later, using a casting mold 2 having a cavity 3 corresponding to the shape of the casting 1.

[0079] The casting method in this embodiment is a die casting method, and the casting 1 is a die casting.

[0080] First, the casting 1 to be produced in this embodiment will be explained in detail.

[0081] FIG. 1 is an explanatory view of the overall configuration of the casting 1, while FIG. 2 is an explanatory view of the state of parts of the casting 1 and casting portions formed in the melt path at the time of casting connected together. Reference numerals of the casting mold 2 are also shown.

[0082] As shown in FIG. 1 and FIG. 2, the casting 1 produced by this die casting method is a front end panel 10 that is a part of the frame of an automobile. The front end panel 10 is a frame part for attachment of a heat exchanger (radiator, condenser, etc.), headlights, etc. at the front of an automobile. The front end panel 10 is comprised of a body 11 and openings 12. The body 11 is comprised of a frame part 101 forming the overall shape and surrounds 102 formed around the openings 12. The surrounds 102 are formed by smooth curved surfaces and are designed so as to smoothly guide air blown from fans when attaching radiator fans in the openings 102.

[0083] The openings 12 are formed inside the surrounds 102. The islands 121 in the openings 12 of this embodiment form part mounts for mounting motors of the fans. The connecting portions 122 form stays for supporting the islands 121. The connecting portions 122 bridge the islands 121 and the surrounds 102 and support the islands 121 and fans fixed to the islands 121.

[0084] Note that the islands 121 may have other parts such as the above fans and pulleys mounted on them.

[0085] Next, the casting mold 2 will be explained.

[0086] The casting mold 2 of the present embodiment, as shown in FIG. 3, has a three-part structure of a fixed mold 21, an intermediate mold 22, and a movable mold 23. Further, as shown in FIG. 2 and FIG. 3, the intermediate mold 22 and movable mold 23 are provided between them with a cavity 3 having a body cavity 31 for forming the body 11 and an island/connecting portion cavity 32 for forming the islands 121 and connecting portions 122 in the openings 12, body gates 311 connected to the body cavity 31, and opening gates 321 connected to the island/connecting portion cavity 32.

[0087] As shown in FIG. 3, the fixed mold 21 and intermediate mold 22 are provided between them with a runner 33 for introducing the melt into the body gates 311 and the opening gates 321.

[0088] The intermediate mold 22 is provided with body pin gates 312 connecting the runner 33 and the body gates 311 and opening pin gates 322 connecting the runner 33 and the opening gates 321. The melt fed into the runner 33 fills the cavity 3 through the body pin gates 312 and body gates 311 and through the opening pin gates 322 and opening gates 321.

[0089] As shown in FIG. 2, the intermediate mold 22 and the movable mold 23 have between them a balance runner 330 provided at least at part of the section between the body pin gates 312 and the body gates 311 and at least at part of the section between the opening pin gates 322 and opening gates 321.

[0090] In the present embodiment, as shown in FIG. 2, a plurality of the body gates 311 and opening gates 321 are provided. The body gate 311 connected to the portion at the middle of the body cavity 31 is formed long along the shape of the balance runner 330.

[0091] As shown in FIG. 3, the body pin gates 312 and the opening pin gates 322 are reversely tapered to expand in channel area from the fixed mold 21 toward the movable mold 23, that is, toward the cavity 3.

[0092] In the present embodiment, as shown in FIG. 8, a body pin gate 312 (or opening pin gate 322) is provided at cavity inserts 221 to 223 detachably inserted into an cavity insert setting hole 220 provided in the intermediate mold 22. Specifically, a cylinder able to be inserted into the circular-section through hole, that is, the cavity insert set hole 22, is comprised of the cavity inserts 221 to 223. In this embodiment, a cylinder divided into three parts is used. Further, the cavity inserts 221 to 223 are provided with tapered through holes. These three through holes are connected to form the tapered body pin gate 312 (or opening pin gate 322).

[0093] As shown in FIG. 3, the movable mold 23 is provided with a plurality of ejector pins 26 for pushing out the formed casting 1 in the cavity 3 from the cavity 3. The ejector pins 26 are connected by a pin frame 261 and are designed to simultaneously move to push out the casting 1. Further, the ejector pins 26 are provided to abut against the balance runner 330 near the positions of the body pin gates 312 connected to the balance runner 330.

[0094] Further, as shown in FIG. 9, the portion where the body pin gate 312 (or opening pin gate 322) connects with the runner 33 is provided with a constricted part 319 where the channel area is greatly locally reduced.

[0095] As shown in FIG. 10, the end part 302 of the body pin gate 312 (or opening pin gate 322) is provided with a distributer 239 formed by the wall surface of the cavity 3 projecting out toward the inlet 301 of the body pin gate 312 (or opening pin gate 322). In this example, the end part 302 of the body pin gate 312 forms a connecting part 303 connecting with the balance runner 330. The distributer 239 is formed at this connecting part 303. Further, the distributer 239 is formed at the movable mold 33 side at the cavity 3 and is also a projection projecting out toward the direction of the intermediate mold 32.

[0096] In this example, to improve the mold releasability, explained later, at least part of the draft at the inner wall of the cavity 3 at the movable mold 23 side, that is, the angle of the side wall in the cavity 3 expanding with respect to the intermediate mold 22, is set to not more than 1°. Further, the draft of the distributer 238 is also set to not more than 1°.

[0097] In this example, as shown in FIG. 2, the runner 33 is branched into a body runner 331 for introducing the melt into the body pin gates 312 and a opening runner 332 for introducing the melt into the opening pin gates 322. Further, the body runner 331 and the opening runner 332 are adjusted in inside diameter so that the rates of filling the melt into them become substantially equal.

[0098] As shown in the drawing, the opening runner 332 is provided in a shape resembling the shape of the island 121. Specifically, since the island 121 is ring shaped, it is provided in circular curved shape matching with this.

[0099] As shown in FIG. 3, the movable mold 21 is provided with a pouring portion 34 connected to the runner 33. The pouring portion 34 has an injection sleeve 342 having a pouring port 343 for pouring the melt and an injection plunger 341 for sending melt poured into the injection sleeve 342 to the runner 33 under pressure.

[0100] As shown in the figure, the movable mold 23 is provided with a gas venting passage 35 for discharging gas in the cavity 3 to the outside of the casting mold 2. In the middle of the gas venting passage 35 is provided a pressure reducing means 4 for evacuating the gas in the cavity 3 to reduce the pressure in the cavity 3.

[0101] The pressure reducing means 4 is comprised of a vacuum pump 41 and vacuum tank 42.

[0102] The melt is poured into the pouring port 343 of the pouring portion 34 and the vacuum pump 41 is actuated to evacuate the inside of the cavity 3 to reduce the pressure in the cavity 3 to a negative pressure. The plunger 341 injects the melt into the runner 33 and fills the cavity 3.

[0103] Note that the evacuation by the vacuum pump 41 may also be performed at the time of injection by the plunger 341. Further, the pressure reducing means 4 may also be configured with a chill vent.

[0104] The gas vent passage 35 is provided with a cutoff pin 36 so that an excess amount of melt will not flow to the gas venting passage 35 as compared with the volume of the cavity 3 after the melt fills the cavity 3. The passage of the cutoff pin 36 is provided with a vacuum gauge 49 for measuring the vacuum degree in the cavity 3.

[0105] The casting mold 2 is comprised of three molds, that is, the fixed mold 21, intermediate mold 22, and movable mold 23, arranged between a pair of base plates 24. Further, a space 25 is provided between the base plate 24 positioned at the movable mold 23 side and the movable mold 23 so that the pin frame 261 of the ejector pins 26 can be arranged there.

[0106] When producing the casting 1 using the above casting mold 2, first, in the state shown in FIG. 3 and FIG. 4, the melt is poured from the pouring port 343 of the injection sleeve 342 of the pouring portion 34 and the melt is injected to the runner 33 from the injection plunger 341. In the present example, the runner 33, as explained above, is divided into the body runner 331 and the opening runner 332 (see FIG. 2). The melt flows split there.

[0107] The melt injected to the body runner 331 is sent under pressure to the body pin gates 312. At this time, the melt flowing through each body pin gate 312 strikes the distributer 239 (see FIG. 10) formed at the end part 302, whereupon the direction of flow is divided into a flow through the body gate 311 and a flow through the balance runner 330. Further, the melt flows from the body gate 311 to the body cavity 31 and flows to the adjoining body gates 311 through the balance runner 330.

[0108] On the other hand, the melt injected into the opening runner 332 is sent under pressure to the opening pin gates 322. At this time, the melt flowing through each opening pin gate 322 strikes the distributer 239 formed at the end part 302, where the flow is divided to the multiplely branched balance runner 330. Further, the melt flows from the balance runner 330 through the opening gate 321 into the island/connecting portion cavity 32.

[0109] The melt flowing from the opening pin gates 311 to the body cavity 31 fills the body cavity 31 with priority, while the melt flowing from the opening gates 321 to the island/connecting portion cavity 32 fills the island/connecting portion cavity 32 with priority. These melts converge and join at the body cavity 31 or island/connecting portion cavity 32 and fill the cavity 3 as a whole.

[0110] The cavity 3 forms a casting 1 having a shape of the above front end panel 10. Further, the runner 33 forms a runner casting 15 having the shape of the runner 33, while the body pin gates 312 and the opening pin gates 322 form pin gate castings 16 having their shapes. Further, the balance runner 330 forms a balance runner casting 17.

[0111] As shown in FIG. 5, after the casting 1 is formed, the intermediate mold 22 and movable mold 23 are made to move with respect to the fixed mold 21 to separate the fixed mold 21 and intermediate mold 22. At this time, the runner casting 15 formed in the runner 33 between the fixed mold 21 and intermediate mold 22 is moved along with the intermediate mold 22 and movable mold 23 while connected to the pin gate castings 16 formed in the body pin gates 312 and opening pin gates 322 in the intermediate mold 22.

[0112] Next, as shown in FIG. 6, the movable mold 23 is made to move with respect to the intermediate mold 22 to separate the intermediate mold 22 and movable mold 23. At this time, the runner casting 15 sticks in the intermediate mold 22 and is cut from the pin gate castings 16. Next, the pin gate castings 16 are released from the intermediate mold 22.

[0113] At the time of movement of the movable mold 23, the runner casting 15 and the pin gate castings 16 are easily cut. That is, due to the presence of the constricted parts 319 (see FIG. 9) formed in the body pin gates 312 and opening pin gates 322, stress concentration easily occurs and cutting is easy.

[0114] The pin gates 312 and 322 are reversely tapered to expand in channel area toward the cavity 3 as explained above. Therefore, the pin gate castings 16 can also be released from the mold smoothly.

[0115] Next, as shown in FIG. 7, the ejector pins 26 arranged corresponding to positions of the body pin gates 312 are made to move toward the direction where the intermediate mold 22 is positioned with respect to the movable mold 23. At this time, the casting 1 is pushed out from the cavity 3 in the state with the pin gate castings 16 connected and the casting 1 can be released from the movable mold 23.

[0116] Next, the pin gate castings 16, the balance runner casting 17, and other unnecessary portions are removed from the casting 1 to obtain the final casting 1.

[0117] Note that as shown in FIG. 11, the body pin gates 312 and the opening pin gates 322 may be reversely tapered to expand in channel area from the movable mold 23 toward the fixed mold 21. In this case, when making the movable mold 23 move with respect to the intermediate mold 22, the pin gate castings 16 are cut from the casting 1 in the state with the runner casting 15 connected.

[0118] Next, the action and effects of this example will be explained.

[0119] As explained above, in this example, use is made of a casting mold 2 providing the body cavity 31 and the island/connecting portion cavity 32 with gates of the body gates 311 and opening gates 321, respectively, and connecting these gates to the runner 33 through the body pin gates 312 and opening pin gates 322.

[0120] Therefore, it is possible to easily cast the front end panel 10 for an automobile, a casting 1 having a complicated shape, in a state without casting defects.

[0121] That is, the melt supplied into the runner 33 is finally divided into the body gates 311 and the opening gates 321. Further, the melt starts to be filled in the body cavity 31 from the body gates 311, while the melt starts to be filled in the island/connecting portion cavity 32 from the opening gates 321. That is, the melt is sent directly into the body cavity 31 and island/connecting portion cavity 32 through the gates 311 and 321.

[0122] Therefore, it is possible to prevent one cavity from being supplied with melt slower than another cavity and possible to directly and quickly fill the melt in both cavities 31 and 32. Due to this, it is possible to prevent melt from being supplied slow and casting defects from appearing.

[0123] This superior die casting method is realized by employing the above casting mold 2 of the three-part structure and arranging the cavity 3, gates 311, 321, pin gates 312, 322, and runner 33 three-dimensionally. By using this casting mold 2, it is possible to supply the melt directly to the body cavity 31 and the island/connecting portion cavity 32 and possible to easily release the casting 1 from the mold after casting.

[0124] In the above embodiment, it is possible to cast the islands 121 and connecting portions 122 of the front end panel 10 without casting defects and possible to produce a front end panel 10 with a high quality. The front end panel 10, as explained above, can be formed integrally with the body 11, part mounts as the islands 121, and stays as the connecting portions 122 by a single casting operation. For this reason, it is possible to reduce the casting cost.

[0125] In the above embodiment, the casting 1 to which the present invention was applied was made a front end panel 10, but the present invention may also be applied to various other products of shapes having islands 121 and connecting portions 122. Also, the casting 1 was explained as being made of a metal, but the present invention may also be applied to various other materials.

[0126] In the above embodiment, a method for filling a melt into a cavity 3 through body gates 311 and opening gates 321 and a casting mold 2 used for the same were explained. When casting a product 1, however, it is also possible to use a method of filling a melt into the cavity 3 from only the opening gates 321 using a casting mold 2 provided with only opening gates 321.

[0127] While the invention has been described with reference to specific embodiments chosen for purpose of illustration, it should be apparent that numerous modifications could be made thereto by those skilled in the art without departing from the basic concept and scope of the invention.

[0128] The present disclosure relates to subject matter contained in Japanese Patent Application No. 2001-203913, filed on Jul. 4, 2001, the disclosure of which is expressly incorporated herein by reference in its entirety.

Claims

1. A casting method for casting a product having a body, a opening provided so as to pass through the body, an island provided separated from the body in the opening, and a connecting portion joining the island and body using a mold having a cavity corresponding to the shape of the product,

the mold being provided with a body gate connected to a body cavity for forming the body in the cavity and a opening gate connected to an island/connecting portion cavity for forming the island and connecting portion in the opening in the cavity;

the body gate and opening gate being connected to a runner for introducing a melt into them; and

the melt fed into the runner being filled in the cavity through the body gate and the opening gate.

2. A casting method as set forth in claim 1, wherein:

the mold has a three-part structure of a fixed mold, intermediate mold, and movable mold;

the fixed mold and the intermediate mold are provided between them with said runner;

the intermediate mold and movable mold are provided between them with said cavity, said body gate, and said opening gate;

the intermediate mold is provided with a body pin gate connecting the runner and the body gate and a opening pin gate connecting the runner and the opening gate; and

the melt sent into the runner is filled in the cavity through the body pin gate and body gate and through the opening pin gate and opening gate.

3. A casting method as set forth in claim 2, comprising:

filling the melt, then moving said intermediate mold and movable mold to separate said fixed mold and said intermediate mold;

moving said movable mold to separate said intermediate mold and movable mold, cutting a runner casting formed in said runner from pin gate castings formed in said body pin gate and said opening pin gate, and releasing said pin gate castings from said intermediate mold;

then releasing the casting from said movable mold in the state with the pin gate castings attached.

4. A casting method as set forth in claim 2 or 3, wherein said intermediate mold and said movable mold have between them a balance runner provided at least at part of the section between said body pin gate and said body gate and at least at part of the section between said opening pin gate and said opening gate and wherein at least part of said melt is supplied from said body pin gate through said balance runner to said body gate and from said opening pin gate through said balance runner to said opening gate.

5. A casting method as set forth in any one of claims 1 to 4, wherein said casting is a front end panel for an automobile and has a body having a surround, a opening formed inside said surround, a part mount as an island arranged in said opening, and stays supporting said part mount as said connecting portion.

6. A casting method as set forth in claim 5, wherein said part mount mounts a motor, fan, or pulley.

7. A casting mold for casting a product having a body, a opening provided so as to pass through the body, an island provided separated from the body in the opening, and a connecting portion joining the island and body,

the mold having a three-part structure of a fixed mold, intermediate mold, and movable mold;

the intermediate mold and movable mold being provided between them with a cavity having a body cavity for forming the body and an island/connecting portion cavity for forming the island and the connecting portion in the opening, a body gate connected to the body cavity, and a opening cavity connected to the island/connecting portion cavity;

the fixed mold and the intermediate mold being provided between them with a runner for introducing melt into the body gate and the opening gate;

the intermediate mold being provided with a body pin gate connecting the runner and the body gate and a opening pin gate connecting the runner and the opening gate; and

the melt sent into the runner being filled in the cavity through the body pin gate and body gate and through the opening pin gate and opening gate.

8. A casting mold as set forth in claim 7, wherein a plurality of at least one of said body gate and said opening gate are provided.

9. A casting mold as set forth in claim 7 or 8, wherein said body pin gate and/or said opening pin gate is reversely tapered to expand in channel area from said fixed mold toward said movable mold or from said movable mold toward said fixed mold.

10. A casting mold as set forth in any one of claims 7 to 9, wherein said body pin gate and/or said opening pin gate is provided at an cavity insert detachably inserted in an cavity insert setting hole provided in said intermediate mold.

11. A casting mold as set forth in any one of claims 7 to 10, wherein a draft of at least part of an inner wall of said cavity at said movable mold side is not more than 1°.

12. A casting mold as set forth in any one of claims 7 to 11, wherein said movable mold is provided with a plurality of ejector pins for pushing out the casting formed in the cavity from said cavity.

13. A casting mold as set forth in claim 12, wherein said ejector pins are provided to abut against said casting near body pin gates and/or opening pin gates.

14. A casting mold as set forth in any one of claims 7 to 11, wherein said intermediate mold and said movable mold have between them a balance runner provided at least at part of the section between said body pin gate and said body gate and at least at part of the section between said opening pin gate and said opening gate.

15. A casting mold as set forth in claim 14, wherein said movable mold is provided with a plurality of ejector pins for pushing out the casting formed in the cavity from said cavity and wherein said ejector pins are provided to abut against said balance runner near the positions of body pin gates connected to said balance runner.

16. A casting mold as set forth in claim 15, wherein a projection projecting out in the direction of the intermediate mold is provided near a joining portion of said body pin gate and/or opening pin gate and said balance runner.

17. A casting mold as set forth in any one of claims 7 to 16, wherein an end part formed at said movable mold in said body pin gate and/or opening pin gate is provided with a distributer projecting out toward an inlet of said body pin gate and/or said opening pin gate.

18. A casting mold as set forth in claim 17, wherein said distributer is shaped with a draft of at least part of not more than 1°.

19. A casting mold as set forth in any one of claims 7 to 18, wherein a portion where said body pin gate and/or said opening pin gate connects with said runner is provided with a constricted part reduced in channel area.

20. A casting mold as set forth in any one of claims 7 to 19, wherein said runner is branched into a body runner for introducing said melt into said body pin gate and a opening runner for introducing said melt into said opening pin gate.

21. A casting mold as set forth in claim 20, wherein said body runner and said opening runner are adjusted in inside diameter so that the rates of filling said melt in them become substantially equal.

22. A casting mold as set forth in claim 20 or 21, wherein said opening runner has a shape similar to the shape of said island.

23. A casting mold as set forth in any one of claims 7 to 22, wherein said cavity is connected to a pressure reducing means for reducing the pressure in said cavity.

24. A casting mold as set forth in any one of claims 7 to 23, wherein said casting is a front end panel for an automobile and has a body having a surround, a opening formed inside said surround, a part mount as an island arranged in said opening, and stays supporting said part mount as said connecting portion.

25. A casting mold as set forth in claim 24, wherein said part mount mounts a motor, fan, or pulley.

26. A casting method for casting a product having a body, a opening provided so as to pass through the body, an island provided separated from the body in the opening, and a connecting portion joining the island and body using a mold having a cavity corresponding to the shape of the product,

the mold having a body cavity for forming the body in the cavity, an island/connecting portion cavity for forming the island and the connecting portion in the opening in the cavity, and a opening gate connected to the island/connecting portion cavity, the opening gate being connected to a runner introducing melt into it;

the melt fed into the runner being filled in the cavity through the opening gate.

27. A casting mold for casting a product having a body, a opening provided so as to pass through the body, an island provided separated from the body in the opening, and a connecting portion joining the island and body,

the mold having a three-part structure of a fixed mold, intermediate mold, and movable mold;

the intermediate mold and movable mold being provided between them with a cavity having a body cavity for forming the body and an island/connecting portion cavity for forming the island and the connecting portion in the opening and a opening cavity connected to the island/connecting portion cavity;

the fixed mold and the intermediate mold being provided between them with a runner for introducing melt into the opening gate;

the intermediate mold being provided with a opening pin gate connecting the runner and the opening gate; and

the melt sent into the runner being filled in the cavity through the opening pin gate and opening gate.