JP6316151B2 - Casting method and apparatus, and cast product obtained thereby - Google Patents

Description

  The present invention relates to a casting processing method and apparatus for performing directional solidification by keeping a molten metal in a feeder, and a cast product obtained thereby.

  In casting processing, in order to prevent the formation of shrinkage cavities and improve product yield, it is widely practiced to install a feeder method outside the product. Since the molten metal undergoes volume shrinkage when it transforms (solidifies) from the liquid phase to the solid phase, it causes poor shrinkage in the product area. In order to compensate for this volume shrinkage, surplus molten metal is supplied to the hot water, and the molten metal is supplied from the molten metal to the product portion to eliminate shrinkage and ensure the soundness of the product.

  Here, if the molten metal in the presser solidifies faster than the molten metal in the cavity (product part), the molten metal cannot move, so that the volume shrinkage cannot be compensated. For this reason, generally, the solidification rate is made smaller than the molten metal in the cavity by storing a large amount of molten metal in the feeder. That is, so-called directional solidification is realized, in which the molten metal in the cavity is solidified first, and then the molten metal in the feeder is solidified.

  However, this requires a large amount of molten metal. Further, the feeder part formed by solidification of the molten metal in the feeder has a large shape and a large volume. Since the feeder part is removed from the product part, the material yield is lowered, and eventually, the inconvenience that the cost is increased is becoming apparent.

  Moreover, since the mold cannot be opened until a large amount of the molten metal remaining in the feeder is solidified, the cycle time from the mold closing to the removal of the cast product becomes long, resulting in a disadvantage of low productivity.

  Thus, various proposals have been made to heat the molten metal in the feeder, including Patent Documents 1 to 4. In this case, since the molten metal in the feeder is not easily solidified by heating, it is easy to cause directional solidification, and the amount of molten metal for the feeder can be reduced. For this reason, the cycle time can be shortened.

JP 2005-329450 A JP-A-61-78553 JP 2013-49082 A JP 2013-49083 A

  Thus, heating the molten metal in the feeder is a well-known technique, but the molten metal in the feeder is heated more efficiently so that the amount of molten metal supplied to the feeder can be further reduced. It is requested to do.

  The present invention has been made in order to solve the above-described problems, and can efficiently keep the molten metal in the feeder and can prevent the formation of the shrinkage nest and the casting process method thereof. The object is to provide an apparatus and the castings obtained thereby.

In order to achieve the above object, a casting processing method according to the present invention brings a plurality of sliding molds interposed between a lower mold and an upper mold close to each other, and the upper mold is placed on the lower mold. A step of forming a cavity and a plurality of feeders connected to the cavity;
The molten metal supplied to the hot water is held by the heat retaining means holding member in a state where the hot water is closed by the heat retaining means holding member that contacts one of the upper mold and the plurality of sliding molds. A step of solidifying the molten metal supplied to the cavity to form a solid phase,
Have
The molten metal in the feeder is kept in contact with the upper mold and the heat retaining means holding member.

The casting processing apparatus according to the present invention includes a lower mold,
An upper die that is displaced in a direction approaching or separating from the lower die;
A plurality of slides interposed between the lower mold and the upper mold and displaceable in a direction approaching or separating from each other and forming a cavity and a feeder with the lower mold and the upper mold. Dynamic type,
A heat retaining means holding member for contacting the sliding mold and the upper mold to close the feeder and for retaining a heat retaining means inserted into the feeder;
With
The molten metal in the feeder is kept in contact with the upper mold and the heat retaining means holding member.

  That is, in the present invention, the hot water is first closed by the heat retaining means holding member. For this reason, the heat of the molten metal in the feeder is not dissipated to the atmosphere. Accordingly, the temperature of the molten metal is unlikely to decrease. In addition, since the molten metal in the feeder is in contact with the heat retaining means holding member, it is difficult for the heat of the molten metal to move to the heat retaining means. For this reason, even if the amount of molten metal is small, the temperature drop is small. Combined with the above, the molten metal in the feeder is efficiently kept warm.

  Therefore, even in a small amount of molten metal in the feeder, the cooling rate can be sufficiently reduced as compared with the molten metal in the cavity. As a result, it is possible to realize directional solidification in which the molten metal in the cavity is solidified first, and then the molten metal in the feeder is solidified. That is, when the molten metal in the cavity is solidified to cause volume shrinkage, the molten metal is supplied from the hot metal to the product part. Thereby, it is avoided that the casting defect occurs in the product portion of the cast product.

  In addition, the amount of molten metal supplied to the feeder, in other words, the total amount of molten metal used is reduced. Therefore, the volume of the feeder part formed by solidification of the molten metal in the feeder is also reduced. For this reason, since the material yield is improved, the cost can be reduced.

  In addition, since the amount of the molten metal remaining in the feeder is small, the time until solidification of the molten metal is completed is short. Therefore, it is possible to shorten the cycle time from closing the mold to taking out the cast product.

  Preferably, the heat retaining means holding member is provided with two leg portions, and a rib portion that abuts against the sliding mold is projected between the two leg portions. The leg is formed with a heat retaining means holding hole for inserting and retaining the heat retaining means. That is, the leg part contains the heat retaining means. Further, both the leg portion and the rib portion are allowed to enter the feeder.

  In this case, the leg part and rib part of the heat retaining means holding member are in contact with the molten metal in the feeder. As described above, since the heat retaining means is included in the leg portion and the contact area between the heat retaining means holding member and the molten metal is increased by the rib portion, the heat retaining effect on the molten metal in the feeder is further improved.

  Here, if the molten metal is supplied to the feeder while the gas (generally the atmosphere) remains in the feeder, a gas back pressure is generated, making it difficult for the molten metal to flow into the feeder. In order to avoid this, it is preferable to form a gas vent in the heat retaining means holding member. This is because in this case, the gas in the feeder can be easily led out to the atmosphere via the gas vent.

  Moreover, it is preferable that the heat retaining means holding member is held by either the upper mold or the sliding mold. In this case, the heat retaining means holding member is displaced integrally with the upper mold or the sliding mold. Accordingly, since a displacement mechanism for displacing the heat retaining means holding member separately from the upper mold or the sliding mold is not required, there is an advantage that the configuration of the casting apparatus is simplified.

  When performing casting in the above-described configuration, it is preferable that the temperature of the heat retaining means holding member is set to be 1 to 100 ° C. lower than the solidus temperature of the molten metal in the feeder. Specifically, when the solidus temperature of the molten metal in the feeder is 600 ° C., the heat generation amount of the heat retaining means may be controlled so that the temperature of the heat retaining means holding member is 500 to 599 ° C. .

  In the conventional technique for heating the molten metal in the feeder, the temperature of the heated body is set to be equal to or higher than the solidus temperature of the molten metal, and when the feeder is no longer needed, the heater is removed from the feeder and heating is stopped. However, in this case, a displacement mechanism for displacing the heating body is necessary, and the configuration of the casting apparatus becomes complicated. Further, since the molten metal in the feeder starts to solidify after the heating body is taken out, the waiting time until the mold can be opened is increased accordingly.

  On the other hand, in the above case, since the temperature of the heat retaining means holding member is lower than the solidus temperature of the molten metal, the molten metal in the feeder is gradually solidified while being kept warm. For this reason, it is not necessary to take out the heat retaining means holding member in order to promote solidification of the molten metal in the feeder. Therefore, since a displacement mechanism for displacing the heat retaining means holding member is unnecessary, the configuration of the casting apparatus can be simplified. Further, since the amount of the molten metal in the feeder is small, the time until solidification is completed is shortened, and it becomes easy to shorten the waiting time until the mold can be opened. Eventually, the cycle time for casting can be shortened.

Here, a cavity to perform casting process includes a disc-shaped portion forming portion that forms a disk shaped portion, the annular portion forming portion for forming an annular portion surrounding the disc-shaped portion, the disc-shaped portion and the A plurality of connecting portion forming portions forming a plurality of connecting portions connected to both of the annular portions are defined. In this case, the hot water may be formed at a location where each of the connecting portion forming portions is connected to the annular portion forming portion. This is because this portion is a portion that requires hot water (replenishment of molten metal).

  In this case, pouring may be performed from the disk shape portion forming portion. Thereafter, the molten metal flows from each of the plurality of connecting portion forming portions to the annular portion forming portion. Furthermore, in the annular part forming part, the molten metal flowing in from the connecting part forming part flows toward another connecting part forming part adjacent to the connecting part forming part. Therefore, in the said annular part formation part, the molten metal which flows toward another said connection part formation part adjacent from one said connection part formation part merges.

Wherein the upper mold, that form a reservoir recess in a portion corresponding to the joining point. And it is good to store the molten metal which flowed and merged as mentioned above in the recessed part for storage. That is, the merged molten metal is caused to flow into the storage recess.

  At the joining point of the molten metal, defects (oxide film or the like) due to joining are likely to occur. On the other hand, when the molten metal that has joined together as described above flows (captured) into the storage recess, when a defect due to the merge occurs, the molten metal that flows into the storage recess is solidified. It becomes the formed convex part. In other words, it is easy to avoid the occurrence of defects due to confluence in the annular portion formed by the annular portion forming portion, in other words, the product.

Furthermore, the casting according to the present invention includes a disk-shaped portion,
An annular part surrounding the disk-shaped part;
A plurality of connecting portions connected to both the disk-shaped portion and the annular portion;
Have
The disc-shaped portion is connected to a plan portion extending in a direction orthogonal to the diameter direction of the annular portion,
The annular portion is characterized in that a feeder portion protruding in the same direction as the plan portion is formed at a location where each of the connecting portions is continuous.

  That is, the cast product includes a disk-shaped part forming part that forms a disk-shaped part, an annular part-forming part that forms an annular part surrounding the disk-shaped part, and the disk-shaped part and the annular part. It is obtained by pouring hot water into a cavity in which a plurality of connecting portion forming portions forming a plurality of connecting portions connected to both are defined.

  When the heat retaining means holding member is provided with two legs, holes corresponding to the legs are formed in the feeder part of the cast product. Since there are two legs, the number of holes is also two.

Corresponding to the fact that the storage recess is formed in the upper mold, the cast product is formed with a protrusion protruding in the same direction as the feeder part between the adjacent feeder parts. .

  An example of such a cast product is a wheel casting material. In this case, the hub corresponds to the disk-shaped portion, and each of the spokes and the rim corresponds to the connecting portion and the annular portion.

  According to the present invention, the hot water is closed by the heat retaining means holding member, and the molten metal in the hot water is brought into contact with the heat retaining means holding member. Since the hot metal is blocked, the heat of the molten metal in the hot metal is not dissipated to the atmosphere, so that the temperature of the molten metal is hardly lowered. In addition, although the molten metal is in contact with the heat retaining means holding member, the heat transfer from the molten metal is small, so that the temperature is hardly lowered even if the molten metal is small. As described above, the molten metal in the feeder is efficiently kept warm.

  For this reason, even if the amount of molten metal in the feeder is small, the cooling rate of the molten metal can be sufficiently reduced as compared with the molten metal in the cavity. Therefore, when the molten metal in the cavity is solidified to cause volume shrinkage, the molten metal is replenished from the feeder to ensure the soundness of the product. Thereby, it is avoided that the casting defect occurs in the product portion of the cast product.

  Moreover, since the supply amount of the molten metal to the feeder can be reduced, the volume of the feeder is also reduced. For this reason, since the yield of the molten metal is improved, it is easy to reduce the cost.

1 is an overall schematic perspective view of a cast product (a casting material for a motorcycle wheel) according to an embodiment of the present invention. It is a principal part schematic perspective view of the casting processing apparatus for obtaining the said casting. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. It is a general | schematic whole perspective view from the viewpoint of the surface side which forms the cavity of the upper mold | type which comprises the said casting processing apparatus. It is a schematic whole front view of the heat insulation block body (heat insulation means holding member) which comprises the said casting processing apparatus.

  Hereinafter, preferred embodiments of the casting processing method according to the present invention will be described in relation to a casting processing apparatus for carrying out the casting processing method and a cast product obtained by the casting processing method, with reference to the accompanying drawings. This will be described in detail.

  First, a cast product will be described. FIG. 1 is an overall schematic perspective view of a casting material 10 of a motorcycle wheel which is a cast product according to the present embodiment. The casting material 10 is made of an aluminum alloy, for example, AC4CH specified by Japanese Industrial Standard (JIS), and is obtained by casting.

  The casting material 10 has a hub 12 (disk-shaped portion), an annular rim 14 (annular portion), and five spokes 16 (connecting portions) connected to both the hub 12 and the rim 14. . Each spoke 16 is formed with a thin portion 18 for weight reduction.

  The hub 12 is connected with a plan unit 20. The extending direction of the plan portion 20 is substantially orthogonal to the diameter direction of the hub 12 and the rim 14. Therefore, when the casting material 10 is in such a posture that the diameters of the hub 12 and the rim 14 extend along the horizontal direction, the design part 20 extends along the vertical direction.

  The rim 14 has an inner peripheral end surface 22, an outer peripheral end surface 24, and side end surfaces 26a and 26b. The hub 12 is located on the inner peripheral end face 22 side of the rim 14, and thus the rim 14 surrounds the hub 12. Further, the spoke 16 is continuous with the inner peripheral end face 22 of the rim 14.

  Further, on the side end face 26b of the rim 14, a feeder part 28 is formed so as to protrude at a place where the spokes 16 are continuous. The height of the wall on the inner peripheral end face 22 side of the feeder part 28 rises significantly as compared with the outer peripheral end face 24. That is, a level difference is generated in the feeder part 28 from the inner peripheral end face 22 toward the outer peripheral end face 24.

  In this case, since the spokes 16 are five, there are also five feeders 28. The feeders 28 are spaced apart from each other at substantially equal intervals. For this reason, each feeder 28 is positioned at the apex of a virtual regular pentagon. Further, the feeder part 28 protrudes in the same direction as the design part 20, and the extending direction thereof is the same as that of the design part 20.

  Two holes 29 are formed in each hot water feeder 28. The hole 29 will be described later.

  On the side end surface 26 a of the rim 14, a convex portion 30 is further formed so as to protrude between the adjacent feeder portions 28, 28. That is, the five convex parts 30 are provided so that it may become the position pinched | interposed between the adjacent feeder parts 28. FIG. The distance L1 from one feeder 20 to the projection 30 and the distance L2 from the remaining one feeder 28 to the projection 30 are substantially the same. Accordingly, the convex portions 30 are spaced apart from each other at substantially equal intervals. For this reason, each convex portion 30 is located at the apex of a virtual regular pentagon. Moreover, the convex part 30 protrudes in the same direction as the design part 20 and the feeder part 28, and the extending direction thereof is the same as that of the design part 20 and the feeder part 28.

  The above shape of the casting material 10 relates to the flow direction of the molten metal when performing casting. This point will be described later.

  Next, the casting apparatus will be described. FIG. 2 is a schematic perspective view of a main part of the casting apparatus 40 according to the present embodiment, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. The casting processing apparatus 40 includes a lower die 42 having a substantially disk shape, and a plurality of (four in the present embodiment) sliding die sliding on the lower die 42, that is, a first sliding die 44a. The second sliding mold 44b, the third sliding mold 44c and the fourth sliding mold 44d, the lower mold 42 and the first to fourth sliding molds 44a to 44d, and the cavity 46 and the feeder shown in FIG. And an upper mold 50 forming 48. The first to fourth sliding dies 44a to 44d have substantially the same shape, but are given different reference numerals for convenience of explanation. In order to facilitate understanding, a boundary line M is drawn between the cavity 46 and the feeder 48.

  The lower mold 42 is a so-called fixed mold that has a substantially disk shape and is positioned and fixed to a base (not shown). At the center of the lower mold 42, a core 52 (see FIG. 3) for forming the hub 12 is provided. In addition, a guide rail 54 for guiding each of the first to fourth sliding dies 44a to 44d is formed on the lower die 42 so as to protrude (see FIG. 2). The guide rail 54 extends along a direction in which the first to fourth sliding dies 44a to 44d approach or separate from each other.

  On the other hand, an engagement recess 56 is formed in the first to fourth sliding dies 44a to 44d. By engaging each engagement recess 56 with the guide rail 54, the first to fourth sliding dies 44 a to 44 d are displaced along the guide rail 54 in a predetermined direction. The first to fourth sliding dies 44a to 44d are individually provided with first to fourth displacement mechanisms (for example, hydraulic cylinders) not shown. The first to fourth sliding dies 44a to 44d are individually displaced under the action of the first to fourth displacement mechanisms. These first to fourth displacement mechanisms are basically energized synchronously. Of course, in this case, the first to fourth sliding dies 44a to 44d are displaced simultaneously.

  As shown in FIG. 3, heater holding holes 60 for inserting the heaters 58 are formed in the first to fourth sliding dies 44a to 44d, respectively. The heater holding hole 60 extends so as to be inclined with respect to the vertical direction. Only one heater holding hole 60 is formed in the first sliding mold 44a, the third sliding mold 44c, and the fourth sliding mold 44d, and two heater holding holes 60 are formed in the second sliding mold 44b. Yes.

  The upper mold 50 includes a cylindrical part 62 and a flange part 64 having a diameter larger than that of the cylindrical part 62. The lower mold 42 is operated under the action of a fifth displacement mechanism (for example, a hydraulic cylinder) (not shown). It moves in the direction which approaches or leaves | separates. In other words, the upper mold 50 is a movable mold that moves up and down.

  As the upper die 50 is lowered and the flange portion 64 comes into contact with the upper end surfaces of the first to fourth sliding dies 44a to 44d that are close to each other (see FIG. 2), the bottom surface of the cylindrical portion 62 is the cavity 46. Form.

  As shown in FIG. 3, a hub forming portion 66 (disk shape portion forming portion) that forms the hub 12, a rim forming portion 68 (ring portion forming portion) that forms the rim 14, and the spoke 16 are formed in the cavity 46. A spoke forming part 70 (a connecting part forming part) is defined. Of course, five spoke forming portions 70 are connected to both the hub forming portion 66 and the rim forming portion 68, and five are formed corresponding to the number of the spokes 16.

  A pouring port 72 is formed substantially at the center of the bottom surface of the cylindrical portion 62. A pouring pipe 74 is provided at the pouring port 72, and a guide rod 76 is connected to the pouring pipe 74. In the present embodiment, the molten metal L reaching the cavity 46 and the feeder 48 is poured from the pouring port 72 via the guide rod 76 and the pouring pipe 74. That is, there is no place other than the pouring port 72 where the molten metal L is introduced.

  Further, as shown in FIG. 4, the first concave portion 78 having a shape corresponding to the substantially upper half shape of the hub 12 and the shape corresponding to the substantially upper half shape of the spoke 16 are formed on the bottom surface of the cylindrical portion 62. A second recess 80 and a third recess 82 having a shape corresponding to the shape of the substantially upper half of the rim 14 are formed in a recessed manner. The first recess 78, the second recess 80, and the third recess 82 together with the lower mold 42 and the first to fourth sliding molds 44a to 44d form a hub forming portion 66, a spoke forming portion 70, and a rim forming portion 68. To do.

  Here, in the cylindrical part 62, five hot-water supply forming parts 84 having a shape in which a part of the side peripheral wall is cut out are formed. That is, the hot water forming portion 84 is formed by a depression directed from the outer peripheral wall side to the inner peripheral wall side of the cylindrical portion 62. Each of the hot water forming portions 84 is located at a location where each of the second concave portions 80 (spoke forming portions 70) is continuous with the third concave portions 82 (rim forming portions 68). Further, the hot water forming portion 84 is connected to the third recess 82 and is opened at the flange portion 64.

  Further, a storage recess 86 having a shape in which a part of the outer peripheral wall of the cylindrical portion 62 is slightly cut out toward the inner peripheral wall is formed in the approximate middle between the adjacent hot-water forming portions 84 and 84. Is done. For this reason, the storage recess 86 has a shape in which a part of the third recess 82 is further depressed to the flange portion 64 side. Since there are five feeder formation portions 84, there are also five storage recesses 86.

  In the flange portion 64, the hot water forming portion 84 opens as described above. Further, as shown in FIG. 2, heater holding holes 90 for holding the heater 88 (see FIG. 3) are formed in the vicinity of each hot water forming portion 84.

  Each of the hot water forming portions 84 is inserted with a heat retaining block 92 as a heat retaining means retaining member. As shown in FIG. 5, the heat retaining block 92 has two legs 94 a and 94 b, a main body 96, and a wide head 98. Since the step portion 99 formed at the opening of the hot water forming portion 84 is narrower than the head portion 98, when the heat retaining block 92 is inserted into the hot water forming portion 84, the head portion 98 becomes the step portion. 99 is dammed up. By this damming, the heat insulation block body 92 is positioned and fixed.

  For convenience of explanation, assuming that the end surface of the main body 96 facing the upper mold 50 is the front surface and the end surface facing the first sliding mold 44a is the rear surface, the front surface is in contact with the upper mold 50, while the rear surface is the first surface. Abuts against one sliding mold 44a. That is, the heat retaining block 92 is interposed between the upper mold 50 and the first sliding mold 44a. A part of the rear surface is an inclined surface inclined according to the shape of the first sliding die 44a. The first sliding mold 44a has been described above as an example, but the same applies to any of the second to fourth sliding molds 44b to 44d.

  As can be understood from the above, the clearance between the upper die 50 and the first to fourth sliding dies 44a to 44d is filled by the main body 96 of the heat retaining block 92 (see FIG. 3). Therefore, the molten metal L does not rise beyond the lower end surface of the main body portion 96. That is, the feeder 48 is a space formed by any one of the upper mold 50 (the feeder formation portion 84), the first to fourth sliding dies 44a to 44d, and the lower end surface of the main body 96, and the heat insulation block body. 92 functions as a lid member that uses the feeder 48 as a closed space.

  On the other hand, the two leg portions 94 a and 94 b projecting from the main body portion 96 toward the lower mold 42 side enter the feeder 48. Accordingly, the legs 94 a and 94 b come into contact with the molten metal L in the feeder 48. The leg portions 94a and 94b are inclined in accordance with the inclination of the upper die 50 and the first sliding die 44a (or any of the second to fourth sliding die 44b to 44d).

  The heat retaining block 92 is formed with two heater retaining holes 102a and 102b for retaining the heaters 100a and 100b, which are heat retaining means, from the head 98 to the substantially distal ends of the leg portions 94a and 94b. Yes. As described above, since the leg portions 94a and 94b are in contact with the molten metal L in the feeder 48, the molten metal L is kept warm by the heat insulating block 92 whose temperature is increased under the action of the heaters 100a and 100b.

  A thin plate-shaped rib portion 104 is provided between the leg portions 94a and 94b. Specifically, the rib portion 104 is connected to the rear surface of the main body portion 96 and is inclined. For this reason, the rear surface of the rib portion 104 is in any one of the first to fourth sliding molds 44a to 44d. Abut. On the other hand, the front surface of the rib portion 104 is in a position biased to the rear surface side from the heater holding holes 102a and 102b. That is, the rib part 104 is thinner than the leg parts 94a and 94b. The protruding length of the rib portion 104 from the main body portion 96 is set to be smaller than that of the leg portions 94a and 94b. Therefore, the molten metal L in the feeder 48 enters between the leg portions 94 a and 94 b and is blocked by the rib portion 104.

  Further, in the main body 96, a gas vent 106 is formed between the heater holding holes 102a and 102b. One end of the gas vent 106 is opened at a portion of the front surface of the main body 96 that is not blocked by the upper mold 50, and the other end is opened at the head 98.

  The casting processing apparatus 40 according to the present embodiment is basically configured as described above. Next, its operational effects will be described in relation to the casting processing method according to the present embodiment. .

  In order to obtain the wheel casting material 10 (see FIG. 1), first, the mold is closed to obtain the state shown in FIG. For this purpose, the first to fourth displacement mechanisms are urged to bring the first to fourth sliding dies 44a to 44d closer to each other. At this time, the first to fourth sliding dies 44 a to 44 d are smoothly displaced while being guided by the guide rail 54. This is because the engaging recess 56 is engaged with the guide rail 54.

  After the first to fourth sliding dies 44a to 44d are displaced to the forward end, the fifth displacement mechanism is then energized to lower the upper die 50 toward the lower side. When the flange portion 64 of the upper mold 50 comes into contact with the upper end surfaces of the first to fourth sliding molds 44a to 44d, the mold is closed and the cavity 46 is formed. At the same time, the hot metal forming portion 84 (see FIG. 4) of the upper die 50 is surrounded by the first to fourth sliding dies 44a to 44d. Since the heat insulating block body 92 is inserted in advance in the opening of the hot water forming portion 84, the hot water as a closed space surrounded by the upper mold 50, the first to fourth sliding molds 44a to 44d, and the heat insulating block body 92. 48 is formed continuously with the cavity 46.

  Thus, in the present embodiment, the heat retaining block 92 can be displaced integrally with the upper mold 50. For this reason, it is not necessary to provide a mechanism for displacing the heat retaining block 92 separately from the upper mold 50. Therefore, the structure of the casting processing apparatus 40 can be simplified.

  Needless to say, the heaters 58, 88, 100a, and 100b are inserted into the heater holding holes 60, 90, 102a, and 102b in advance of mold closing. The heaters 58, 88, 100a, 100b are preferably energized before mold closing. In this case, when the mold is closed, the temperatures of the first to fourth sliding molds 44a to 44d, the heat retaining block 92, and the upper mold 50 are sufficiently increased. Because it can be done.

  Next, the molten metal L is transferred from a ladle (not shown) to the guide rod 76. As the molten metal L, for example, AC4CH, which is a kind of aluminum alloy, may be selected.

  The molten metal L is guided by the guide rod 76 and flows, and flows into the cavity 46 through the pouring pipe 74 through the pouring pipe 74. The molten metal L is first introduced into the hub forming portion 66 including the first recess 78 and is distributed to the spoke forming portions 70 including the second recess 80 by contacting the core 52. The molten metal L further flows through each spoke forming portion 70 and then flows into the rim forming portion 68 including the third recess 82.

  The rim forming portion 68 has a shape that is bifurcated from a connecting position with the spoke forming portion 70 and curved into an arc shape. For this reason, the molten metal L that has flowed into the rim forming portion 68 from the spoke forming portion 70 branches off at the connecting portion between the spoke forming portion 70 and the rim forming portion 68, and as shown by the arrows in FIG. From one spoke forming portion 70 toward the spoke forming portion 70 adjacent to the spoke forming portion 70. Therefore, a flow of the molten metal L that flows in directions opposite to each other is generated in the rim forming portion 68.

  The molten metal L that has flowed through the rim forming portion 68 from opposite directions joins at a substantially middle point between the adjacent spoke forming portions 70. Here, the upper mold 50 is formed with a storage recess 86 at a location corresponding to the intermediate point. For this reason, the molten metal L which merged raises the inside of the storage recessed part 86. FIG. That is, the merged molten metal L is stored in the storage concave portion 86, and finally, the storage concave portion 86 is filled with the molten metal L.

  Oxides are likely to be generated at the junction of the molten metal L. However, in the present embodiment, the molten metal L merged as described above is pushed out to the storage recess 86. That is, the merged molten metal L is solidified in the storage concave portion 86 to become the convex portion 30 (see FIG. 1). For this reason, when the oxide is generated, the generated portion is the convex portion 30. Eventually, by forming the storage recess 86, it is possible to avoid the generation of oxide on the rim 14.

  When the molten metal L is filled in the entire cavity 46 including the rim forming portion 68, the excess molten metal L flows into the feeder 48. The molten metal L enters between the two leg portions 94a and 94b of the heat insulation block body 92, is blocked by the front surface of the rib portion 104 in the horizontal direction, and under the main body portion 96 of the heat insulation block body 92 in the vertical direction. Damped at the end face. That is, the leg portions 94 a and 94 b, the front surface of the rib portion 104, and the lower end surface of the main body portion 96 are in contact with the molten metal L.

  While the molten metal L flows into the feeder 48, the gas (generally the atmosphere) in the feeder 48 is discharged to the outside via the gas vent 106 formed in the heat retaining block 92. Therefore, it is avoided that gas remains in the feeder 48 and that the flow of the molten metal L into the feeder 48 is prevented by the gas back pressure generated due to this.

  Since the opening of the feeder 48 is closed by the heat retaining block 92, the feeder 48 is a closed space, so that the heat of the molten metal L in the feeder 48 is not dissipated to the atmosphere. In addition, the two leg portions 94a and 94b, the main body portion 96, and the rib portion 104 of the heat retaining block 92 are preheated to a predetermined temperature by the heaters 100a and 100b inserted into the heater holding holes 102a and 102b. Furthermore, heaters 58 and 88 are disposed in the vicinity of the feeder 48. In combination with the above, the molten metal L in the feeder 48 is efficiently kept warm.

  In addition, it is preferable to set the temperature of the heat insulation block 92 to 1-100 degreeC low temperature rather than the solidus line temperature of the molten metal L, and it is still more preferable to set it to 5-55 degreeC low temperature. Specifically, when the molten metal L is AC4CH, the solidus temperature is 555 ° C. Therefore, in this case, the heat generation amount of the heaters 100a and 100b may be controlled so that the temperature of the heat retaining block 92 is in the range of 455 to 554 ° C, more preferably 500 to 550 ° C.

  On the other hand, the heat of the molten metal L in the cavity 46 is taken away by the lower mold 42, the first to fourth sliding molds 44 a to 44 d, and the upper mold 50. For this reason, as the temperature of the molten metal L in the cavity 46 decreases, the molten metal L starts to solidify relatively quickly.

  On the other hand, the molten metal L in the hot metal 48 in contact with the heat retaining block 92 is solidified slowly. This is because the molten metal L in the feeder 48 is kept warm as described above. That is, the cooling rate of the molten metal L in the cavity 46 can be increased, and the cooling rate of the molten metal L in the feeder 48 can be decreased. Thereby, directional solidification is realized.

  Therefore, when the molten metal L in the cavity 46 undergoes volume shrinkage as it solidifies, the molten metal L that is still in the liquid phase in the feeder 48 flows into the cavity 46. Eventually, since the molten metal L is replenished from the feeder 48 to the cavity 46, it is possible to avoid the occurrence of shrinkage nests or the like at the site that becomes the product (wheel).

  As described above, according to the present embodiment, the feeder 48 is closed, or the legs 94a and 94b and the ribs 104 of the heat retaining block 92 are brought into contact with the molten metal L in the feeder 48. The molten metal L in the feeder 48 is efficiently kept warm. For this reason, even if the molten metal L in the feeder 48 is small, the solidification rate can be made lower than that of the molten metal L in the cavity 46. Therefore, since it is not necessary to use a large amount of the molten metal L in order to suppress the occurrence of casting defects, the yield of the molten metal L is improved.

  In the conventional technique for heating the molten metal L in the feeder 48 (see, for example, Patent Documents 1 to 4), the temperature of the heating body is set to be equal to or higher than the solidus of the molten metal L, and the heated body becomes unnecessary. The heating is stopped by taking out the molten metal from the feeder 48, and the solidification of the molten metal L in the feeder 48 is thereby started. Therefore, a displacement mechanism for displacing the heating body and taking it out from the feeder 48 is required. In addition, since the solidification start timing of the molten metal L in the feeder 48 is relatively late, it is possible to shorten the time until mold opening becomes possible, and hence the cycle time from the start of mold closing to the opening of the mold. Is not easy.

  On the other hand, in the present embodiment, since the temperature of the heat insulation block 92 is set to be lower than the solidus temperature of the molten metal L, the molten metal L in the feeder 48 is maintained in a liquid phase state for a long time. There is no. In other words, by setting the temperature of the heat retaining block 92 to be lower than the solidus temperature of the molten metal L, the molten metal L in the heated metal 48 is moved at a slow speed while the molten metal is being heated. It can be solidified. Therefore, it is not necessary to remove the heat insulation block 92 from the hot water 48 after the hot water is no longer needed. This also contributes to simplifying the casting apparatus 40 by eliminating the need for a displacement mechanism for displacing the heat retaining block 92 separately from the upper mold 50. Note that when the cooling rate of the molten metal L in the feeder 48 is increased after the feeder is no longer needed, the heating of the heaters 58, 88, 100a, and 100b may be stopped.

  In addition, since the solidification start timing of the melt L in the feeder 48 is relatively early, it is easy to shorten the cycle time from the start of mold closing to the mold opening.

  The upper die 50 is displaced (raised) in a direction away from the lower die 42 under the action of the fifth displacement mechanism, and the first to fourth sliding dies 44a under the action of the first to fourth displacement mechanisms. By displacing .about.44d away from each other, the mold is opened and the cast product is exposed. Since the rear surface of the rib portion 104 is in contact with the first to fourth sliding dies 44a to 44d, the contact area between the cast product and the first to fourth sliding dies 44a to 44d is small. Therefore, since it is avoided that the casting product is welded to the first to fourth sliding molds 44a to 44d, the first to fourth sliding molds 44a to 44d are relatively easily detached from the casting product.

  As shown in FIG. 1, the cast product includes a hub 12 formed by a hub forming portion 66, a spoke 16 formed by a spoke forming portion 70, and a rim 14 formed by a rim forming portion 68. This is a casting material 10. In the casting material 10, the hub 12 is connected with a design portion 20 in which the molten metal L at the pouring port 72 is solidified. Further, the rim 14 is formed with a raised portion 28 in which the molten metal L of the molten metal 48 is solidified, and a convex portion in which the molten metal L of the storage concave portion 86 is solidified between the adjacent molten metal portions 28. 30 is formed to protrude.

  In addition, the hole 29 of the feeder part 28 is a trace that the leg parts 94a and 94b are detached. That is, the hole 29 is formed by the leg portions 94a and 94b.

  During the casting process, the molten metal L that has flowed and joined from the opposite direction of the rim forming portion 68 is stored in the storage recess 86 (see FIG. 4), and therefore, the occurrence of a hot water boundary in the rim 14 is avoided. Has been. Further, since the molten metal L is replenished from the feeder 48, the occurrence of shrinkage cavities in the product portion (hub 12, spoke 16, and rim 14) of the casting material 10 is avoided. In addition, when a casting defect occurs, the occurrence location is the feeder part 28 or the convex part 30. That is, according to the present embodiment, it is easy to avoid the occurrence of casting defects in the product portion of the casting material 10.

  Next, the plan part 20, the feeder part 28, the convex part 30 and the like are removed from the casting material 10. Thereby, a wheel is obtained. As described above, since casting defects are avoided in the hub 12, the spoke 16, and the rim 14, a high-quality and high-strength wheel can be obtained.

  Moreover, since the volume of the feeder part 28 and the convex part 30 is small, the removal operation | work from the rim | limb 14 is easy. And since these are small volumes, the yield of the molten metal L improves.

  The present invention is not particularly limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

  For example, the structure of the feeder 48 in the present invention is not only adopted in the casting processing apparatus 40 for obtaining a casting material 10 for a motorcycle wheel as a casting product, but a casting processing apparatus for obtaining other casting products. It is also possible to adopt it.

  Further, the heat retaining block 92 may be held in a sliding manner.

DESCRIPTION OF SYMBOLS 10 ... Casting material 12 ... Hub 14 ... Rim 16 ... Spoke 20 ... Plan part 28 ... Hot-water supply part 30 ... Convex part 40 ... Casting processing apparatus 42 ... Lower mold | type 44a-44d ... 1st-4th sliding mold 46 ... Cavity 48 ... Fewer 50 ... Upper mold 58, 88, 100a, 100b ... Heater 60, 90, 102a, 102b ... Heater holding hole 62 ... Cylindrical part 64 ... Flange part 66 ... Hub formation part 68 ... Rim formation part 70 ... Spoke Forming part 72 ... Pouring port 78 ... 1st recessed part 80 ... 2nd recessed part 82 ... 3rd recessed part 84 ... Pressurizing hot water forming part 86 ... Recessed part 92 ... Insulation block body 94a, 94b ... Leg part 96 ... Body part 98 ... Head Part 104 ... Rib part 106 ... Gas vent

Claims (14)

A plurality of sliding molds interposed between the lower mold and the upper mold are brought closer to each other, and the upper mold is brought closer to the lower mold, so that a cavity and a plurality of feeders connected to the cavity are formed. Forming, and
The molten metal supplied to the hot water is held by the heat retaining means holding member in a state where the hot water is closed by the heat retaining means holding member that contacts one of the upper mold and the plurality of sliding molds. A step of solidifying the molten metal supplied to the cavity to form a solid phase,
As well as have a,
In the cavity, a disk-shaped part forming part that forms a disk-shaped part, an annular part forming part that forms an annular part surrounding the disk-shaped part, and both the disk-shaped part and the annular part are connected. Defining a plurality of connecting portion forming portions forming a plurality of connecting portions;
Forming the hot water at a location where each of the connecting portion forming portions is connected to the annular portion forming portion;
Pouring hot water from the disk-shaped part forming part, and then flowing the molten metal from each of the plurality of connecting part forming parts to the annular part forming part,
Furthermore, in the annular part forming part, the molten metal flowing in from the connecting part forming part is caused to flow toward another connecting part forming part adjacent to the connecting part forming part,
In the annular part forming part, at the confluence where the molten metal flowing from the connecting part forming part toward another adjacent connecting part forming part joins, at the storage concave part formed in the upper mold , Store the molten metal,
And the molten metal in the said hot metal is kept in contact with the said upper mold | type and the said heat retention means holding member, The casting method characterized by the above-mentioned. 2. The casting method according to claim 1, wherein the heat retaining means holding member is provided with two legs that enter the feeder, and the heat retaining means is inserted into a heat retaining means holding hole that reaches the legs. Hold
Further, a rib portion that abuts against the sliding mold is formed between the two leg portions so that the rib portion enters the feeder and contacts the molten metal in the feeder. A casting method.   The casting method according to claim 1 or 2, wherein a gas vent is formed in the heat retaining means holding member, and the gas in the feeder is led to the atmosphere through the gas vent.   The casting method according to any one of claims 1 to 3, wherein the heat retaining means holding member is held by either the upper die or the sliding die.   The casting method according to any one of claims 1 to 4, wherein the temperature of the heat retaining means holding member is set to 1 to 100 ° C lower than the solidus temperature of the molten metal in the feeder. A characteristic casting method. The casting method according to any one of claims 1 to 5, wherein a casting material for a wheel is obtained as a cast product. With the lower mold,
An upper die that is displaced in a direction approaching or separating from the lower die;
A plurality of slides interposed between the lower mold and the upper mold and displaceable in a direction approaching or separating from each other and forming a cavity and a feeder with the lower mold and the upper mold. Dynamic type,
A heat retaining means holding member for contacting the sliding mold and the upper mold to close the feeder and for retaining a heat retaining means inserted into the feeder;
With
In the cavity, a disk-shaped part forming part that forms a disk-shaped part, an annular part forming part that forms an annular part surrounding the disk-shaped part, and both the disk-shaped part and the annular part are connected. A plurality of connecting portion forming portions that form a plurality of connecting portions are defined, and the heat retaining means holding member is disposed at a location where each of the connecting portion forming portions is connected to the annular portion forming portion,
The disk-shaped part forming part is connected to a pouring port, and each of the connecting part forming parts becomes a flow path of the molten metal from the disk-shaped part forming part to the annular part forming part,
Furthermore, the annular part forming part serves as a flow path for the molten metal from the connecting part forming part to another connecting part forming part adjacent to the connecting part forming part,
The upper mold is formed with a storage recess for storing the molten metal that has flowed and joined from the connecting part forming part to another adjacent connecting part forming part in the annular part forming part,
And the molten metal in the said feeder is made to contact the said upper mold | type and the said heat retention means holding member, and it heat-resists. The casting processing apparatus according to claim 7 , wherein the heat retaining means holding member has two legs that enter the feeder.
A heat retaining means holding hole for inserting and holding the heat retaining means reaches the leg,
Furthermore, a rib portion is formed between the two leg portions so as to protrude into contact with the sliding mold and to enter the feeder and to contact the molten metal in the feeder. Casting processing equipment. In casting processing apparatus according to claim 7 or 8, wherein the heat insulating means holding member, casting processing apparatus characterized by gas vent for deriving the gas in the feeder to the atmosphere is formed. The casting apparatus according to any one of claims 7 to 9 , wherein the heat retaining means holding member is held by either the upper mold or the sliding mold. The casting apparatus according to any one of claims 7 to 10, wherein a casting material for a wheel is obtained as a cast product. A disk-shaped part;
An annular part surrounding the disk-shaped part;
A plurality of connecting portions connected to both the disk-shaped portion and the annular portion;
Have
The disc-shaped portion is connected to a plan portion extending in a direction orthogonal to the diameter direction of the annular portion,
In the annular portion, the hot water portions protruding in the same direction as the plan portion are respectively formed at locations where the connecting portions are continuous ,
Furthermore, the cast part characterized by the convex part protruding in the same direction as the said feeder part being formed between the said feeder parts adjacent . 13. The cast product according to claim 12 , wherein two holes are formed in the feeder part. The cast product according to claim 12 or 13, wherein the cast product is a casting material of a wheel.

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