JP4521135B2 - Automotive wheel casting equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a casting apparatus used for molding automobile wheels.
[0002]
[Prior art]
In the process of casting an automobile wheel by pouring molten metal into the mold cavity, the center of the wheel serving as the hub part is used as a sprue, and the molten metal is injected from the spoke part molding runway into the rim part molding runway. After completely filling and injecting to the innermost end of the part forming water channel, the process proceeds to the cooling process, and gradually solidifies from the edge of the rim part forming water channel to the gate through the spoke part forming water channel. Automobile wheels are manufactured.
[0003]
In such a cooling process, if the solidification when cooling the molten metal injected into the cavity is inappropriate, bubble nests, shrinkage nests, cracks, surface defects, shape defects, etc. are likely to occur, By properly cooling the molten metal, it is possible to manufacture a sound product without such defects. In addition, since a predetermined shape can be formed by replenishing the molten metal as needed with respect to heat shrinkage that occurs when the molten metal solidifies, a cooling means that appropriately solidifies and replenishes the molten metal in the cooling process is used. This is an important point for efficiently obtaining a sound product.
[0004]
[Problems to be solved by the invention]
Since automobile wheels have complex shapes, the thickness of each part is different, so the degree of solidification at each part during cooling is different, and there is a tendency to cause defects such as defects as described above. is there. Therefore, by actively cooling the vicinity of the sprue, which is a relatively high temperature region, during the cooling process, and shortening the time from the start of solidification of the rim end to the end of solidification in the entire region, the entire wheel In general, a solid product is produced by creating a situation in which the solidification of the steel gradually proceeds from the rim portion to the gate.
[0005]
As the above-mentioned automobile wheel, the hub part to which the thin-walled spoke is joined is a part that requires high mechanical strength due to the nature of the product, and therefore, generally has a thick shape. . For this reason, it is necessary to enhance the cooling action on the hub portion so that the solidification of the hub portion is appropriately performed with respect to the solidification of the surrounding portions. As a cooling method for this purpose, conventionally, a passage for injecting a cooling fluid into the nest is provided, and the passage is configured such that the flow rate of the cooling fluid is increased at the most necessary part of the cooling action, or A configuration in which a cooling unit is provided separately and the cooling unit is installed at a predetermined location of the nest is common. However, in the former, a passage is provided by, for example, making a hole in the insert, so that the durability of the insert is lowered and the cost for processing the passage is increased. In the latter case, in order to avoid adverse effects due to thermal expansion and contraction deformation between the nest and the cooling body, it is necessary to flatten the contact surface between the nest and the cooling body, and it is difficult to increase the cooling action locally. It was.
The present invention aims to solve such problems.
[0006]
[Means for Solving the Problems]
The present invention provides an automobile wheel casting apparatus, wherein a thin wall portion is formed on a spout side of a spoke portion molding runner, a surface facing the spoke portion molding runner is defined as a thin side partial plane, and the thin portion is further formed. The nest that defines the cavity of the automobile wheel mold in which the surface that faces the molded portion of the thick-walled spoke is the thick-side main plane, and the entire cooling section that contacts the thick-side main plane And a cooling part body having a point cooling part in contact with the thin side partial plane, and heat between the point cooling part and the thin side partial plane or / and between the whole cooling part and the thick side main plane. It is characterized by interposing an expansion / contraction shock absorbing material.
[0007]
As described above, the cooling part body is brought into contact with the thin part formed on the side of the sprue of the molded part of the spoke part and the thick part other than the thin part as the nest of the wheel mold for the automobile. As a result, it is possible to forcibly cool the hub part to which the spokes are joined in accordance with the cooling speed by the point cooling part while increasing the cooling speed of the automobile wheel as a whole. As a result, the solidification of the molten metal can proceed sequentially from the outermost end of the rim toward the pouring gate as much as possible, and a sound product can be efficiently manufactured.
[0008]
As the above-mentioned cooling part body, it has a stepped structure consisting of a point cooling part and an overall cooling part, and the point cooling part is mainly intended to locally cool the part where the spoke joins to the hub part. It may be installed only at a position corresponding to the hub part to which the spoke part of the wheel for joining is attached, or may be installed over the entire area of the hub circumference. On the other hand, the entire cooling unit may be configured over the entire circumference of the wheel, or a plurality of cooling unit bodies may be configured corresponding to the installation position of the point cooling unit.
[0009]
As a cooling method of such a cooling part body, general water cooling, air cooling, or the like can be used. A flow path through which the cooling fluid flows is provided in the cooling part body, and the cooling fluid is injected into the flow path. In this way, cooling can be performed. Such a cooling fluid flow path can also be provided in each of the point cooling section and the entire cooling section, whereby the cooling action of the point cooling section can be further enhanced.
[0010]
As a nesting cooled by the cooling body according to the present invention, in order to obtain an appropriate cooling action from the point cooling part and the whole cooling part, a thin side partial plane and a thick side main plane are formed in the nesting, and contact is made. The contact surfaces of the nest and the cooling unit are in plane contact so that the surface is uniformly cooled.
[0011]
The thickness of the thin portion of the thin side partial plane configured in such a nesting can be an appropriate shape depending on the shape and material of the automobile wheel to be cooled.
[0012]
On the other hand, in the cooling process of the casting apparatus described above, the temperature of the nest is about 400 ° C. to 500 ° C., whereas the cooling body is about 100 ° C. A change occurs in the insert and the cooling unit body, and a compressive load acts on or contacts the contact surface between the point cooling unit and the thin side partial plane and the contact surface between the whole cooling unit and the thick side main plane. The surface may be separated. Therefore, a configuration as shown in FIG. 5 (not a publicly known example) in which an escape space is provided in anticipation of thermal expansion and contraction deformation has been considered, but in the escape space provided in advance between the entire cooling unit and the thick-walled main plane, Since the thermal conductivity of air is low, the cooling action becomes insufficient, and the necessary cooling effect cannot be obtained. Therefore, as a result of further intensive studies, the inventor can absorb the above-mentioned thermal expansion and contraction deformation between the point cooling part and the thin side partial plane or / and between the whole cooling part and the thick side main plane. It came to interpose a thermal expansion shrinkage buffer material. By using the thermal expansion / shrinkage cushioning material in this way, it is possible to prevent a load or a space from being created between the cooling body and the insert due to thermal expansion / shrinkage deformation, and a sufficient cooling effect can be obtained. It was to be demonstrated.
[0013]
Since the shape of the nest and the cooling unit, the temperature difference between the nest and the cooling unit, etc. affect the thermal expansion / shrinkage deformation, the contact surface for interposing the above-mentioned thermal expansion / contraction member is the point cooling unit and the thin wall Compare the thermal expansion / shrinkage deformation that occurs on the contact surface with the side partial plane and the thermal expansion / shrinkage deformation that occurs on the contact surface between the entire cooling section and the thick side main plane, and the contact that generates the larger amount of deformation. It is effective to interpose a thermal expansion / shrinkage buffer material on the surface. Further, depending on the deformation amount and the deformation action, a thermal expansion / shrinkage cushioning material may be interposed on both contact surfaces.
[0014]
As the above-mentioned thermal expansion buffer material, it is required that the cooling action from the cooling body can be sufficiently transmitted. Therefore, it is proposed to use a material having high thermal conductivity. Further, by making the thermal expansion / shrinkage buffer material an elastic body having high elasticity, even if the nest and the cooling body are subjected to thermal expansion / shrinkage deformation, both are always in contact via the thermal expansion / shrinkage buffer material. Therefore, sufficient heat conduction can be performed. In addition, a material having sufficient heat resistance in the temperature range of the insert during casting is preferable. Furthermore, you may use the material whose coefficient of thermal expansion is higher than a nest | insert or a cooling part body.
[0015]
As such a thermal expansion and contraction material, a carbon material such as copper or graphite can be used. In particular, it is proposed to use a graphite sheet member made of graphite having a high thermal conductivity, high elasticity, and heat resistance, or a carbon fiber nonwoven fabric made of carbon fiber short fibers. In particular, the graphite sheet member has a high recovery rate when compressed, and therefore has high durability against repeated use.
[0016]
As the above-mentioned thermal expansion / shrinkage buffer material, the thickness of the material is generally inversely proportional to the thermal conductivity, so that the thinner is preferable from the viewpoint of thermal conductivity. On the other hand, it is necessary to have a thickness that can support the amount of thermal expansion / shrinkage deformation of the nest and the cooling body. It is necessary to decide.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a casting mold 1 for molding an automobile wheel. A cavity 5 is formed by combining the upper mold 2, the lower mold 3, and the horizontal molds 4 and 4. The cavity 5 includes a hub portion 54, a spoke portion 52, and a rim portion 53, and molten metal is injected from the pouring gate 51 through the molten metal injection path 7 from the stalk 6, and the spoke portion 52 and the rim portion 53 are formed from the hub portion 54. The molten metal is filled through the runner. A cooling unit 9 is installed in a nest 8 that is assembled to the lower mold base to form the lower mold 3, and the molten metal is solidified by the cooling action of the cooling unit 9 to produce an automobile wheel.
[0018]
FIG. 2 is an enlarged view of the insert 8a and the cooling unit 9a of the mold 1. As shown in FIG. A thin portion 10 is formed in the insert 8a as a place where the hub portion 54 between the gate 51 and the spoke portion 52 can be locally cooled, and a thick portion 12 is formed in addition to the thin portion. A point cooling part 14 a of the cooling part 9 a is pressed into contact with the thin-side partial plane 11 of the thin-walled part 10 via a thermal expansion / shrinkage cushioning material 13. Further, the entire cooling part 16a of the cooling part 9a is in contact with the thick side main plane 15a of the thick part 12. Here, a graphite sheet member is used as the thermal expansion / shrinkage buffer material 13.
[0019]
The thermal expansion / shrinkage cushioning material 13 may be interposed between the thick-side main plane 15a of the insert 8a and the entire cooling section 16a of the cooling section 9a, and further, the thin-side partial plane 11a. And the point cooling part 14a, and between the thick-side main plane 15a and the whole cooling part 16a of the cooling part body 9a.
[0020]
The cooling body 9a is provided with a flow path 17a for flowing cooling water, and a cooling action is generated in the cooling body 9a by flowing cooling water through the flow path 17a at a predetermined cooling time. Also, other cooling fluid such as cooling air can be used for the flow path 17a.
[0021]
On the other hand, as shown in FIG. 3, the shapes of the cooling body 9b and the insert 8b according to the present invention are also proposed. In the structure of FIG. 3, the thin portion 10 of the insert 8b is wider than the structure of FIG. 2, so that the pressure contact surfaces of the thin side partial plane 11b and the point cooling portion 14b are widened, and the gate 51 and the spoke portion 52 The effect of cooling the hub portion 54 between them can be further improved. Further, in such a structure, when the mold 1 is processed, the insert 8b can be processed relatively easily, so that an increase in the mold processing cost can be suppressed.
[0022]
Next, the casting process in the present invention will be described with reference to FIGS. 1 and 2. FIG.
As a material for automobile wheels, for example, an aluminum alloy is melted by heating in a melting furnace or the like to form a molten metal. A molten aluminum at a high temperature of about 700 ° C. is poured from the gate 51 of the automobile wheel casting mold 1. The molten metal flows into the cavity 5, passes through the spoke portion 52 from the hub portion 54, reaches the rim portion 53, is filled from the endmost portion of the rim portion 53, and reaches the endmost portion of the rim portion 53. Gradually, the temperature decreases and the progress of solidification begins. A metal material such as an aluminum alloy generally undergoes thermal shrinkage deformation when cooled, and therefore, the aluminum alloy is likely to be cracked or defective. Therefore, the molten metal is poured from the gate 51 at a predetermined pressure, and the molten metal is replenished so that the product has a desired shape.
[0023]
When the molten metal is introduced in this way, the mold is heated to a high temperature by the molten metal, and particularly at a temperature of about 400 ° C. to 500 ° C. near the gate 51 of the insert 8a. In order to cool the nest 8a that has reached a high temperature, in the cooling part 9a, the whole cooling part 16a contacts the thick-side main plane 15a to cool the whole nest 8a, and the point cooling part 14a is thermally expanded and contracted. The gate part 51 and the hub part 54 of the spoke part 52 are locally forcedly cooled by being pressed against the thin-walled partial plane 11a via the buffer material 13 (graphite sheet member). Thereby, the thick hub portion 54 can be cooled faster than the thin gate 51 while increasing the cooling speed of the entire wheel, so that the molten aluminum alloy can be cooled from the extreme end of the rim portion 53 to the gate 51. As a result, it is possible to coagulate sequentially as much as possible. Therefore, it is possible to cast a healthy product free from defects by rapidly proceeding with solidification while replenishing the molten metal against heat shrinkage of the aluminum alloy.
[0024]
In addition, by locally forcibly cooling the hub portion 54 that is thick as described above, the internal and external differences in the degree of solidification progress that occurs in the thickness direction can be reduced. The effect of preventing defects is also obtained.
[0025]
In such a cooling process, since the temperature of the insert 8a is about 400 ° C. to 500 ° C. with respect to the cooling portion 9a of about 100 ° C. during cooling, the cooling portion 9a and the insert 8a are caused by heat conduction between them. However, the point cooling part 14a has a large shrinkage deformation of the cooling body 9a due to the difference in heat shrinkage deformation action. In order to prevent the generation of space due to this, the thermal expansion / shrinkage cushioning material 13 as described above is interposed. Since the thermal expansion / shrinkage buffer material 13 is compressed and deformed by pressing the cooling body 9a against the insert 8a at normal temperature, the thermal expansion / contraction deformation of the point cooling unit 14 and the cooling of the insert 8a. Even if the body 9a is separated, only the compression deformation of the thermal expansion / shrinkage cushioning material 13 is relieved according to the deformation, and it can continue to contact both the insert 8a and the cooling body 9a. The heat conduction at can be performed properly.
[0026]
On the other hand, in the mold 1 having the cooling unit body 9 ′ of the conventional example as shown in FIG. 4 (the same reference numerals are used for the common parts), the entire cooling unit 16 ′ of the cooling unit body 9 ′ is thick. Since the contact 8 is in contact with the side main plane 15 ′, and the insert 8 ′ is cooled as a whole, the cooling of the spoke portions 52 and the gate 51 having a relatively thin shape is accelerated, and the wall thickness is increased. The cooling rate of the hub portion 54 having a shape becomes duller than that of the spoke portion 52 and the end of the gate 51. Therefore, as mentioned above, the gate 51 is cooled and solidified earlier than the hub portion 54, and it becomes difficult to replenish the hub portion 54 with molten metal. It can cause a decrease in efficiency.
[0027]
Further, in the mold 1 having the cooling part 9 ″ of the comparative example shown in FIG. 5 (the same reference numerals are used for the common parts), the thermal expansion / shrinkage cushioning material 13 is placed on the thin side partial plane of the insert 8 ″. 11 ″ and the point cooling part 14 ″ of the cooling part 9 ″ are not used, so in anticipation of thermal expansion and contraction deformation caused by heat conduction between the insert 8 ″ and the cooling part 9 ″, The escape space 18 is provided between the thick-side main plane 15 "and the whole cooling part 16". Since the thermal conductivity of air is generally low, the heat conduction of the escape space 18 becomes insufficient. The necessary cooling action may not be obtained.
[0028]
As described above, in the present invention, in the automobile wheel cooling process, the entire cooling part 16a of the cooling part 9a cools the entire insert 8a, and the point cooling part 14a forcibly cools the hub part 54. Can be prevented. Further, by interposing the thermal expansion / shrinkage cushioning material 13 between the point cooling part 14a of the cooling part 9a and the thin side partial plane 11a of the insert 8a, the point cooling part 14a and the thin side partial plane due to thermal expansion and contraction are provided. It is possible to prevent generation of a space between 11a, and it is not necessary to provide a relief space 18 in anticipation of thermal expansion and contraction deformation, so that an appropriate cooling action can be applied to the nest 8a. The present invention is not limited to this embodiment, and can be implemented in various forms without departing from the gist of the present invention, and can be appropriately implemented in manufacturing other than automobile wheels.
[0029]
【The invention's effect】
The present invention provides a cooling unit for an automobile wheel by providing an overall cooling part for cooling the entire insert and a point cooling part for forcibly cooling the hub part, thereby reducing the cooling speed of the automobile wheel by the overall cooling part. Since the hub part can be locally forcedly cooled by the point cooling part according to the cooling rate while enhancing the whole, an appropriate cooling action can be produced as a whole, and the solidification of the molten metal is caused by the rim part. Since a process of sequentially proceeding from the extreme end toward the gate can be created, defects and the like can be prevented and a sound automobile wheel product can be efficiently manufactured.
[0030]
By interposing a thermal expansion / shrinkage cushioning material in either or both of the whole cooling unit and the point cooling unit of the cooling unit in contact with the nest, a space is created in the contact part between the cooling unit and the nest by thermal expansion / shrinkage deformation. It is possible to prevent the occurrence of the occurrence, and further, since it is not necessary to provide an escape space in advance in anticipation of thermal expansion and contraction deformation, an appropriate cooling effect can always be obtained.
[0031]
A high cooling effect and durability can be obtained by using a sheet member made of graphite as an elastic body having excellent thermal conductivity and high heat resistance for the thermal expansion / shrinkage buffer material.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an automotive wheel mold 1 according to the present invention.
FIG. 2 is a specific example of an insert 8a and a cooling unit 9a according to the present invention.
FIG. 3 is a specific example of the insert 8b and the cooling unit 9b according to the present invention.
FIG. 4 is an example of a conventional insert 8 ′ and a cooling unit 9 ′.
FIG. 5 is a comparative example in which an escape space 18 is set between the insert 8 ″ and the cooling body 9 ″.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mold 8a, 8b Nesting 9a, 9b Cooling part body 11a, 11b Thin side partial plane 13 Thermal expansion contraction shock absorbing material 14a, 14b Point cooling part 15a, 15b Thick side main plane 16a, 16b Whole cooling part

Claims (2)

Forming a thin portion on the spout side of the spoke portion molding runner, forming a surface facing the spoke portion molding runner as a thin side partial plane, and further forming a spoke portion molding runway of the thick portion excluding the thin portion; Nesting that defines a cavity of a wheel mold for an automobile that has an opposing surface as a thick-side main plane,
A cooling part body comprising a whole cooling part in contact with the thick side main plane and a point cooling part in contact with the thin side partial plane;
An automotive wheel casting apparatus comprising a thermal expansion / shrinkage cushioning material interposed between a point cooling section and a thin side partial plane or / and between an entire cooling section and a thick side main plane. The automotive wheel casting apparatus according to claim 1, wherein the thermal expansion / shrinkage buffer material is a sheet member made of graphite.

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