JP5798381B2 - Mold for manufacturing vehicle wheel and method for manufacturing vehicle wheel using the same - Google Patents

Description

  The present invention relates to a mold for manufacturing a vehicle wheel and a method for manufacturing a vehicle wheel using the same.

  The vehicle wheel is used for mounting tires on the vehicle. Since a large load such as vibration or impact is applied to the vehicle wheel during traveling of the vehicle, it is strongly required to have high strength and few quality defects. In order to meet these demands, when manufacturing a vehicle wheel, a low-pressure casting method is widely used (for example, Patent Document 1). The low pressure casting method pressurizes the interface of the molten metal stored in the holding furnace (chamber), pushes the molten metal up in the hot water supply pipe (Stoke), flows into the cavity (cavity) of the mold, and melts in the cavity. It is a casting method that solidifies. By using this low-pressure casting method, it is possible to reduce quality defects and weight variations even in products having complicated uneven shapes.

JP 2001-287016 A

  However, even with the low-pressure casting method, it is still difficult to reduce variations in quality of castings for vehicle wheels and sink defects that are peculiar to castings.

  In view of the above problems, an object of the present invention is to provide a technique capable of reducing variations in quality and sink defects of vehicle wheels.

  According to the present invention, the above-described object can be achieved. Specifically, the following are a mold for manufacturing a vehicle wheel and a method for manufacturing a vehicle wheel using the same.

[1] A cavity for filling a molten metal, and a molten metal flow path for injecting the molten metal into the cavity, the cavity forming a disk molding part extending in a substantially horizontal direction; A rim molding portion extending upward from an outer peripheral edge, and the molten metal flow path opens into the rim molding portion, and the rim molding portion has a rim thickness of the cavity that decreases from above to below. A mold for manufacturing a vehicle wheel having a rim thickness changing region.

[2] The vehicle wheel manufacturing according to [1], wherein the rim forming portion includes an inner bead sheet forming portion at an upper portion, and a lower portion from the inner bead sheet forming portion is the rim thickness change region. Mold.

[ 3 ] The mold for manufacturing a vehicle wheel according to [1] or [ 2], wherein a difference between the maximum rim thickness and the minimum rim thickness of the cavity in the rim thickness change region is 1 mm or more.

[ 4 ] The molten metal is injected into the cavity from the molten metal flow path of the mold for manufacturing a vehicle wheel according to any one of [1] to [3], and the molten metal is filled into the cavity. A method for manufacturing a vehicle wheel, wherein the molten metal is solidified to produce a cast product for the vehicle wheel, and then the cast product for the vehicle wheel is ground to a desired shape.

  According to the vehicle wheel manufacturing mold of the present invention and the vehicle wheel manufacturing method using the same, it is possible to obtain a vehicle wheel with few variations in quality and sink defects.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a vehicle wheel manufacturing mold according to an embodiment of the present invention and a low-pressure casting apparatus including the same. It is an enlarged view in the frame A in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be added without departing from the scope of the present invention.

  A vehicle wheel manufacturing mold of the present invention (hereinafter referred to as “mold of the present invention”) includes a cavity for filling a molten metal and a molten metal flow path for injecting the molten metal into the cavity. . Furthermore, this cavity has a disk molding part that expands in a substantially horizontal direction, and a rim molding part that extends upward from the outer peripheral edge of the disk molding part.

  Further, in the mold of the present invention, the molten metal flow path is opened in the rim forming part. Therefore, in the mold of the present invention, the molten metal can be caused to flow from the molten metal flow path into the rim forming portion of the cavity.

  Further, in the mold of the present invention, as described above, the rim molding part extends upward from the outer peripheral edge of the disk molding part. Therefore, if the molten metal flows into the rim molded part, Depending on the applied pressure and the weight of the molten metal, the molten metal descends to the outer peripheral edge of the disk forming portion, and finally the molten metal can be poured into the center of the molten disk forming portion. Thus, the molten metal can be filled in the entire cavity.

  In the mold of the present invention, a portion corresponding to a rim of a cast product for a vehicle wheel can be formed from the molten metal filled in the rim forming portion. Therefore, the width of the cavity of the rim forming portion matches the thickness of the rim of the cast product for the vehicle wheel. The mold of the present invention has a region in which the width of the cavity at the rim molding portion (hereinafter referred to as “rim thickness” of the rim molding portion) decreases from the upper side to the lower side, so-called rim thickness change region.

  In this specification, the decrease in the rim wall thickness of the cavity from the upper side to the lower side refers to a mode in which the rim wall thickness of the cavity gradually decreases or a mode in which the rim wall thickness decreases in stages [for example, the rim wall thickness of the cavity at position A is α. (Mm), the rim thickness of the cavity is β (mm) from the position A to the lower position B, and the rim thickness of the cavity is γ (mm) from the position B to the lower position C (where α> A mode of decreasing such that β> γ) is included.

  In general, a casting for a vehicle wheel is thick at a portion where a disk and a rim intersect. Reflecting such thickness characteristics, in molds for producing castings for vehicle wheels, generally, the part where the disk forming part and the rim forming part intersect, the so-called intersection is the width of the cavity. Is large and the volume is also large. Due to the characteristics of the width and volume of the cavity, when the molten metal is solidified at the intersection, there is a tendency that the influence of the molten metal shrinks, and in particular, sink defects due to the molten metal shrinkage are likely to occur. In the mold of the present invention, when the rim thickness of the cavity in the rim molding part decreases from the upper side to the lower side, when the molten metal is poured into the rim molding part in the manner as described above, The cross-sectional area of the channel becomes narrower along the flowing direction of the molten metal. As a result, in the mold of the present invention, the directional solidification is improved from the intersecting portion to the rim forming portion. That is, when the molten metal at the intersecting portion contracts due to solidification, the molten metal replenishment from the upper rim forming portion is promoted, so that the molten metal is directed from the bottom to the top at the portion from the intersecting portion to the rim forming portion. It becomes easy to solidify gradually. In addition, when the flow path cross-sectional area of the molten metal in the rim molding part narrows along the flowing direction of the molten metal as in the mold of the present invention, when the molten metal begins to flow into the cavity of the rim molded part, The molten metal spreads in the rim molding part while being in a tightly packed state, and the molten metal is in close contact with the mold wall surrounding the cavity, and is tightly packed in the cavity surrounded by the mold wall. . As a result, directional solidification is further promoted. Since directional solidification is thus improved, the use of the mold of the present invention makes it possible to suppress the occurrence of sink defects at the portion where the disk and rim of the obtained cast product for a vehicle hole intersect.

  In particular, in the mold of the present invention, when the molten metal filled in the intersecting portion is solidified and contracted, the rim thickness of the cavity is changed in the rim thickness changing region from the viewpoint that the molten metal supply from the rim molded portion is promoted. It is preferable that the thickness gradually decreases from the top to the bottom.

  The mold of the present invention can also be used to produce a casting for a vehicle wheel having an inner bead sheet, a hump, and a drop center. In the case of such a use, the mold of the present invention may have a rim molding part having an inner bead sheet molding part or a drop center molding part. From the inner side bead sheet forming portion, a portion corresponding to the inner side bead sheet and hump of the vehicle wheel can be formed. Further, from the drop center forming portion, a portion corresponding to the drop center of the vehicle wheel can be formed.

  In the mold of the present invention, when the rim molding part has an inner bead sheet molding part, the inner side bead sheet molding part may be provided in the upper part in the rim molding part.

  Further, in the mold of the present invention, when the rim molding part has the inner side bead sheet molding part, the molten metal replenishment from the rim molding part is promoted when the molten metal filled in the intersecting part is solidified and contracted. From the viewpoint, the lower part of the rim forming part is preferably a rim thickness changing region from the inner side bead sheet forming part. Further, in this rim thickness changing region, the rim thickness of the cavity is directed from the upper side to the lower side. It is more preferable to decrease gradually.

  In the mold of the present invention, when the rim molding part has an inner side bead sheet molding part and a drop center molding part, the inner side bead sheet molding part is provided at the upper part in the rim molding part, and the drop center molding part is It is good to be provided in the lower part of the inner side bead sheet molding part.

  In the mold of the present invention, when the rim molding part has an inner bead sheet molding part and a drop center molding part, the molten metal from the rim molding part is solidified and contracted when the molten metal filled in the intersecting part is solidified and contracted. From the viewpoint that the replenishment is promoted, it is preferable that the inner side bead sheet forming portion and the drop center forming portion do not have a region where the rim thickness of the cavity increases from the upper side to the lower side. Thus, when there is no region where the rim thickness of the cavity increases from the upper side to the lower side, the rim molding part has a complicated uneven shape such as an inner bead sheet molding part, a hump molding part, or a drop center molding part. Despite being a cavity, the resulting castings for vehicle wheels have fewer variations in quality and sink defects.

  In the mold of the present invention, the difference between the maximum rim thickness and the minimum rim thickness of the cavity in the rim thickness change region is preferably 1 mm or more, and more preferably 3 mm or more. In the mold of the present invention, the upper limit of the difference between the maximum rim thickness and the minimum rim thickness of the cavity in the rim thickness change region is preferably 12 mm, and more preferably 10 mm.

  When the vehicle wheel is manufactured using the mold of the present invention, the molten metal is injected into the cavity from the molten metal flow path to fill the molten metal into the cavity, and the molten metal is solidified as it is to cast the vehicle wheel. It is good to produce a product, and then to grind and process the obtained cast product for a vehicle wheel into a desired shape.

  Hereinafter, the content will be described in detail with reference to a specific embodiment of a mold for manufacturing a vehicle wheel of the present invention.

  FIG. 1 is a schematic view of a vehicle wheel manufacturing mold according to an embodiment of the present invention and a low-pressure casting apparatus equipped with the same. As shown in the figure, the low pressure casting apparatus D includes a mold set S and a base 10 on which the mold set S is placed.

  The mold set S includes three types of molds, such as a lower mold 20, an upper mold 40, and a pair of horizontal molds 30. When these molds are combined to form a mold set S, a cavity 50 is formed inside. The cavity 50 is a cavity having substantially the same shape as the vehicle wheel. [In the schematic diagram of FIG. 1, the vehicle wheel-shaped cavity has an inner side on the upper side and an outer side (external when mounted on the vehicle). The side that can be seen from is facing down]. In this mold set S, the cavity 50 is composed of a disk molding part 51 and a rim molding part 53. By casting the molten metal in the cavity 50, a casting for a vehicle wheel can be formed.

  In the mold set S, the pair of horizontal molds 30 are separated from the surface including the central axis of the vehicle wheel. Each of the mating surfaces of the two horizontal molds 30 has a recess, and when the mating surfaces of the two horizontal molds 30 are mated, a runner 31 is formed. There are one runner 31 on each side of the mold set S, that is, a pair. These runners 31 are substantially L-shaped, and one end of the runner 31 is opened as a side end opening 311 in the rim forming part 53 of the cavity 50, and the other end of the runner 31 is The lower end opening 312 is opened on the lower surface of the horizontal mold 30. Thereby, the molten metal can be caused to flow into the runner 31 from the lower end opening 312, and the molten metal that has flowed into the runner 31 can be injected into the cavity 50 from the side end opening 311. Further, a weir is provided in the side end opening 311 so that the flow path is narrowed.

  In the present mold set S, a recess is formed on the upper surface of the lower mold 20, and the insert 21 is fitted in the recess. By this insert 21, the disk portion of the vehicle wheel can be formed into a desired uneven shape.

  FIG. 2 is an enlarged view in a frame A in FIG. In this enlarged view, the rim molding part 53 and the vicinity of the outer peripheral edge 17 of the disk molding part 51 are depicted. As shown in the figure, in the mold set S, the rim forming portion 53 is formed as a cavity surrounded by the wall surface 19 a of the horizontal mold 30 and the wall surface 19 b of the upper mold 40. The rim molding part 53 is composed of an inner bead sheet molding part 11 at the upper part and a drop center molding part 13 at the lower part. Further, in the present mold set S, the vicinity of the outer peripheral edge 17 of the disk forming portion 51 is a space surrounded by the wall surface 19 a of the horizontal mold 30, the wall surface 19 b of the upper mold 40 and the wall surface 19 c of the lower mold 20. The intersecting portion 12 is formed as a large thickness portion where the rim forming portion 53 intersects. In the present mold set S, in the region L from the lower end 15 of the inner bead sheet forming portion 11 to the lower end 18 of the drop center forming portion 13, the rim thickness W of the cavity 50 gradually decreases from the upper side to the lower side. Here, the rim thickness W of the cavity can be measured using a caliper, and the obtained cast product for a vehicle wheel can be cut and measured from the width of the cross section of the cast product.

  In the mold set S, when the molten metal flows into the rim molding part 53, the molten metal descends from the inner bead sheet molding part 11 to the drop center molding part 13 and flows into the disk molding part 51. At this time, as described above, since the rim thickness W of the cavity gradually decreases in the region L, molten metal replenishment from the inner side bead sheet forming portion 11 to the drop center forming portion 13 and the intersecting portion 12 is promoted. Sink defects are less likely to occur in the thick portion of the cast product formed from the intersection 12. Further, the molten metal flows in a tightly packed space surrounded by the wall surface 19a of the horizontal mold 30 and the wall surface 19b of the upper mold 40. As a result, the molten metal can be filled in the rim molding portion 53 in a uniform and high density state. In this way, when the molten metal is filled and solidified, it becomes possible to obtain a cast product with extremely few quality variations and sink defects.

  As shown in FIG. 1, in the low pressure casting apparatus D, a mold set S is placed on a base 10. An intermediate stalk 70 passes through the base 10. The intermediate stalk 70 can be arranged in a state extending in a direction inclined with respect to the vertical direction. The upper end of the intermediate stalk 70 is connected to the lower end opening 312 of the runner 31.

  Under the base 10, a molten metal holding furnace 60 is disposed. The molten metal M is accommodated in the molten metal holding furnace 60. A holding furnace stalk 75 is attached to the molten metal holding furnace 60. The holding furnace stalk 75 extends in a substantially vertical direction. The upper end of the holding furnace stalk 75 is connected to the lower end of the intermediate stalk 70, and the lower end of the holding furnace stalk 75 is inserted into the molten metal M accommodated in the molten metal holding furnace 60.

  In the low pressure casting apparatus D, a filter R is provided between the runway 31 and the intermediate stalk 70 so that foreign matters mixed in the molten metal can be removed.

  In this low pressure casting apparatus D, gas is supplied into the molten metal holding furnace 60 to pressurize the molten metal M, so that the molten metal M enters the cavity 50 via the stalk (intermediate stalk 70 and holding furnace stalk 75) and the runway 31. Can be sent to. At this time, it is desirable to supply the molten metal M until the cavity 50 and the runner 31 are filled.

  When the cavity 50 and the runner 31 are filled with the molten metal M, the molten metal M may be solidified as it is.

  After the molten metal is solidified in the cavity 50 and the runner 31, when each mold is released, a casting for a vehicle wheel can be obtained.

  About this cast product for vehicle wheels, it is possible to finally obtain a vehicle wheel by grinding each part into a desired shape.

  INDUSTRIAL APPLICABILITY The present invention can be used as a mold for manufacturing a vehicle wheel and a method for manufacturing a vehicle wheel using the same.

10: Base, 11: Inner side bead sheet molding part, 12: Crossing part, 13: Drop center molding part, 15: Lower end (inner side bead sheet molding part), 17: Outer peripheral edge (of disk molding part), 18: Lower end (of the drop center molding part), 19a: (horizontal) wall surface, 19b: (upper mold) wall surface, 19c: (lower mold) wall surface, 20: lower mold, 21: nested, 30: horizontal mold , 31: runner, 40: upper mold, 50: cavity, 51: disc molding section, 53: rim molding section, 60: molten metal holding furnace, 70: intermediate stalk, 311: opening of side end of (runner), 312 : Lower end opening (of runner), D: Low pressure casting apparatus for vehicle wheel, M: Molten metal, R: Filter, S: Mold set.

Claims (4)

A cavity for filling the molten metal, and a molten metal flow path for injecting the molten metal into the cavity,
The cavity has a disk molding part that extends in a substantially horizontal direction, and a rim molding part that extends upward from the outer peripheral edge of the disk molding part,
The molten metal flow path opens to the rim molding part,
The rim forming part is a mold for manufacturing a vehicle wheel having a rim thickness changing region in which the rim thickness of the cavity decreases from the upper side to the lower side.   2. The vehicle wheel manufacturing mold according to claim 1, wherein the rim forming portion has an inner bead sheet forming portion at an upper portion, and a lower portion from the inner bead sheet forming portion is the rim thickness changing region. The mold for manufacturing a vehicle wheel according to claim 1 or 2 , wherein a difference between the maximum rim thickness and the minimum rim thickness of the cavity in the rim thickness change region is 1 mm or more.   The molten metal is injected into the cavity from the molten metal flow path of the mold for manufacturing a vehicle wheel according to any one of claims 1 to 3, the molten metal is filled into the cavity, and the molten metal is solidified. And producing a cast product for the vehicle wheel, and then grinding the cast product for the vehicle wheel to obtain a desired shape.

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