JP2008073763A - Method of manufacturing vehicle wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a vehicle wheel, by which the formability of the preform of the vehicle wheel in plastic working is enhanced more dramatically than before. <P>SOLUTION: In the invented method, molten metal is poured into an inner space of a high-pressure casting mold for forming the preform which has a cylindrical portion and of which the axial cross-section is nearly calathiform or H-shaped. Then the molten metal is solidified by supercooling while being pressurized. The method comprises a preform forming step for forming the preform of a material having supersaturated α phase and dense microstructure, and a rolling step for rolling the outer circumference of the cylindrical portion of the preform into a prescribed shape. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a vehicle wheel such as an aluminum alloy or a magnesium alloy.

  Conventionally, the manufacturing method of vehicle wheels, such as aluminum alloy represented by the following patent document 1, is known well. More specifically, the vehicle wheel manufacturing method of Patent Document 1 includes a molding cavity having a disk part molding space and a rim original part molding space in a mold-clamped state, and the disk part molding described above. A preform for a vehicle wheel having a disk portion and a rim original shape portion is cast by using a mold in which a runner connected to a working space is formed and filling the cavity with a high-pressure molten metal through the runner. A high-pressure casting step, and a processing step for obtaining a rim portion having a final shape or a shape close to the final shape by performing a spinning process with thinning on the original rim shape portion of the preform.

JP 2004-306062 A

  However, the method of Patent Document 1 described above is still sufficient for the preformability of the vehicle wheel preform (ease of molding from the preform to the vehicle wheel (finished product)) in a rolling process such as spinning. It is in a situation that cannot be said.

  Therefore, an object of the present invention is to provide a method for manufacturing a vehicle wheel in which the forming ability of the preform of the vehicle wheel in the rolling process is dramatically improved as compared with the conventional method.

Means and effects for solving the problems

(1) (a) The vehicle wheel manufacturing method of the present invention has a plurality of mold members forming an internal space, has a cylindrical part and a disk part, and has a substantially concave or substantially axial sectional shape. A method of manufacturing a vehicle wheel having a preform molding process using a high-pressure casting mold for molding a preform to be an H-type, wherein the high-pressure casting mold clamps the internal space. It has holding means that can be held wider than the inner space of the rear and is detachable. The holding means is mounted before casting the preform with the high-pressure casting mold. A step of clamping the high pressure casting mold after removing the holding means after casting the reform. (B) Moreover, the manufacturing method of the vehicle wheel of this invention is another viewpoint. WHEREIN: For shaping | molding the preform which has a cylindrical part and a disk part, and the cross-sectional shape of an axial direction becomes a substantially concave shape or a substantially H shape. After supplying molten metal to the internal space of the high-pressure casting mold and solidifying the molten metal while pressurizing the molten metal to form a casting preform, a space is formed in a predetermined portion of the internal space of the high-pressure casting mold. And a preform forming step of forming a vehicle wheel preform by forging by plastic deformation so as to push the cast preform into the space of the predetermined portion while applying pressure. . At this time, you may have the rolling process which rolls further the outer peripheral surface of the cylindrical part in the said preform to a predetermined shape. In addition, when forming the said cast preform in the said preform shaping | molding process, it is preferable to supercool and solidify the said molten metal, pressurizing and forced cooling. (C) Furthermore, the vehicle wheel manufacturing method of the present invention, as another aspect, is for forming a preform having a cylindrical part and a disk part and having an axial cross-sectional shape that is substantially concave or substantially H-shaped. After supplying the molten metal to the internal space of the mold for high pressure casting, the preform is formed by supercooled α phase and a material of dense and refined structure by solidifying the molten metal under pressure and forced cooling. You may have a preform shaping | molding process and the rolling process which rolls the outer peripheral surface of the cylindrical part in the said preform to a predetermined shape.

  According to the configurations of (1), (a) and (b) above, it is possible to provide a method capable of forging a predetermined material for a vehicle wheel immediately after high pressure casting. Further, when the molten metal is supercooled and solidified as in the configurations (a) to (c) of (1) above, a preform made of a material of a supersaturated α phase and a dense and refined structure can be formed. Therefore, since the preform in this case is formed from a material in which the particles are dense and refined, the preform exhibits uniform elongation in plastic working and a large spreadability is obtained. That is, it is possible to provide a manufacturing method capable of dramatically improving the forming ability of the vehicle wheel preform in the rolling process as compared with the conventional method.

(2) In the vehicle wheel manufacturing method of the present invention, in the preform molding step, hot charging is performed so that contamination of the molten metal does not occur, and the molten metal is supplied to the internal space of the high pressure casting mold. Before, the internal space of the high-pressure casting mold is cooled and held at a predetermined temperature or lower, and in the rolling step, the temperature of the preform is lower than the recrystallization temperature of the preform. It is preferable to perform rolling while maintaining a predetermined temperature.

(3) As another aspect, in the vehicle wheel manufacturing method of the present invention, in the preform molding step, the molten metal is hot-charged so as not to contaminate the molten metal, and the molten metal is used as the high-pressure casting mold. Before the hot water is supplied to the internal space, the internal space of the high-pressure casting mold is cooled and held at a predetermined temperature or lower. In the rolling process, the temperature of the preform is changed to the temperature of the preform. It is preferable to perform rolling while maintaining a predetermined temperature higher than the crystal temperature.

  According to the configuration of (2) or (3) above, it is possible to provide a vehicle wheel manufacturing method in which the forming ability of the vehicle wheel preform in the rolling process is further improved.

(4) In the vehicle wheel manufacturing method of the present invention, in the rolling step, the heating and heating are performed so that the temperature is equal to the temperature of the preform heated and held at a predetermined temperature equal to or higher than the recrystallization temperature of the preform. It is preferable to use a held rolling jig.

(5) As another aspect, in the vehicle wheel manufacturing method of the present invention, in the rolling step, the temperature is equal to the preform heated and held at a predetermined temperature equal to or lower than the recrystallization temperature of the preform. It is preferable to use a jig for rolling that is heated and held as described above.

  According to the configuration of the above (4) or (5), it is freed from the sequential increase in deformation resistance due to the cooling of the preform, and the degree of freedom of moldability of the preform is improved.

(6) In the vehicle wheel manufacturing method of the present invention, the high-pressure casting mold uses a Cu-Ni-Si ternary hard copper alloy and has a total volume of at least three times the volume of the preform. It is preferable to have at least one cooling hole formed along the internal space inside the mold body.

  According to the configuration of (6) above, the molten metal supplied to the internal space of the high pressure casting mold can be reliably supercooled. As a result, as a result of densification and refinement with respect to the material constituting the molten metal, unprecedented large ductility can be surely exhibited.

(7) In the vehicle wheel manufacturing method of the present invention, it is preferable that the medium flowing through the cooling hole is turbulently flowed during the supercooling and solidification. Thereby, the molten metal supplied to the internal space of the high pressure casting mold can be more easily supercooled.

(8) In the method for manufacturing a vehicle wheel of the present invention of (1) and (b) above, a pre-strain is applied to the disk portion of the preform that has been high-pressure cast between the preform molding step and the rolling step. It preferably has a predistortion step.

  According to the configuration of the above (8), the cast structure of the disk part in the preform can be further decomposed and refined in the subsequent heat treatment step, so that the vehicle wheel with improved mechanical properties and fatigue strength of the disk part in the vehicle wheel. Can be provided.

(9) In the method for manufacturing a vehicle wheel of the present invention of (1) and (b) above, the temperature heated and maintained at a temperature capable of superplastic processing between the preform molding step and the rolling step. It is preferable to have a forging process in which the preform is forged using a mold heated and held so that the temperature is equal to that of the preform.

  According to the configuration of (9) above, if the preform is heated and held at a temperature at which superplastic processing is possible, if plastic processing is applied to fine crystal grains due to supercooling, the preforms in grain boundaries and grains Dislocation becomes easy to move. Therefore, since plastic flow accompanied by large-scale grain boundary sliding can be generated with a small deformation resistance during forging, it becomes possible to give a large processing rate all at once, and the refined structure becomes finer. . At the same time, the forged part of the preform can be extended greatly. That is, it becomes possible to refine the preform material structure by molding, improve the quality characteristics of the material constituting the preform, and perform precision forging of complex shapes of the preform. Therefore, it is possible to provide a method for manufacturing a vehicle wheel that can reliably obtain a net-shaped vehicle wheel having quality characteristics equivalent to or better than those of conventional products.

(10) In the method for manufacturing a vehicle wheel according to the present invention of (1) and (b) above, between the preform molding step and the rolling step, heating and holding are performed in a hot temperature region equal to or higher than the recrystallization temperature. It is preferable to have a forging process in which the preform is forged using a mold heated and held so that the temperature is equal to that of the preform.

(11) In the method for manufacturing a vehicle wheel of the present invention of (1) and (b) above, between the preform molding step and the rolling step, heating and holding is performed in a warm temperature region below the recrystallization temperature. It is preferable to have a forging process in which the preform is forged using a mold heated and held so that the temperature is equal to that of the preform.

  According to the configuration of the above (10) or (11), it is possible to provide a method for manufacturing a vehicle wheel in which the forming ability of the preform of the vehicle wheel in the rolling process is further improved.

(12) In the vehicle wheel manufacturing method of the present invention, in the preform molding step, before supplying the molten metal to the internal space of the high-pressure casting mold, the internal space of the high-pressure casting mold is preliminarily provided. It is preferable to fill the interior space of the high-pressure casting mold with an inert gas after decompressing, or to fill the interior space of the high-pressure casting mold with an inert gas. Thereby, since it can prevent that a molten metal is oxidized, the molten metal supplied to the internal space of the metal mold | die for high pressure casting can be reliably hold | maintained with high purity. Therefore, an effective means can be secured in combination with the non-oxidized hot water supply method for improving the quality of the preform material, particularly the quality of the design surface of the disk shape.

<First Embodiment>
Hereinafter, the manufacturing method of the vehicle wheel concerning a 1st embodiment of the present invention is explained, referring to drawings. Drawing 1 is a mimetic diagram showing a manufacturing process in a manufacturing method of a vehicle wheel concerning a 1st embodiment of the present invention in order.

  In FIG. 1, 1 is a high pressure casting mold, 2 is a hot water supply pipe, 3 is a pressure cylinder, 4 is a pressure plunger, 6 is a molten metal, and 7 is a preform. The high-pressure casting mold 1 includes an upper mold 1a and a lower mold 1b. Each of the upper mold 1a and the lower mold 1b is provided with a plurality of hole-shaped cooling holes 5 through which a cooling medium passes. Yes. The hot water supply pipe 2 communicates with a middle portion of the cylindrical pressure cylinder 3 so that the molten metal 6 can be supplied from a melting furnace (not shown). The pressure plunger 4 is a columnar member that can move in the internal space of the cylindrical pressure cylinder 3. As a modification, the cooling hole 5 may be a single pipe stretched around the internal space of the high-pressure casting mold 1. The preform 7 is a vehicle wheel precursor having a cylindrical portion 7a (see FIG. 1 (e)) and having an axial cross-sectional shape that is substantially concave or substantially H-shaped.

  The high pressure casting mold 1 is made of a Cu—Ni—Si ternary hard copper alloy having a high heat transfer coefficient. Another example of this material is beryllium copper. Further, the total volume of the high pressure casting mold 1 is formed to be at least three times the volume of the preform 7.

  As the molten metal 6, a light alloy such as a medium-strength aluminum alloy or a magnesium alloy is used. However, the present invention is not limited to this, and it is also possible to use a metal material that can be in another molten state.

  Next, the manufacturing method of the vehicle wheel which concerns on 1st Embodiment of this invention is demonstrated in detail using FIG.

(Preform molding process)
First, the high-pressure casting mold 1 is prepared in a state where the mold is opened (see FIG. 1A). Subsequently, the upper mold 1a and the lower mold 1b are clamped. At this time, the internal space of the high pressure casting mold 1 is maintained at a predetermined temperature or lower. Then, a laminar flow is supplied from the melting furnace (not shown) through the hot water supply pipe 2 using air pressure into the pressurizing cylinder 3 without touching the air (see FIG. 1B).

  Then, the pressure plunger 4 is raised along the inside of the pressure cylinder 3, and the pressure of the melting furnace is lowered with the communication portion between the hot water supply pipe 2 and the pressure cylinder 3 closed by the pressure plunger 4. The molten metal level of the hot water supply pipe 2 is lowered to the standby level (see FIG. 1C). At this time, the internal space of the high pressure casting mold 1 may be preliminarily decompressed and then filled with an inert gas. Next, the pressure plunger 4 is moved in the direction of the high pressure casting mold 1 to fill the internal space of the high pressure casting mold 1 with the molten metal 6, and then the molten metal 6 is pressurized (about 80 MPa to about 200 MPa). While maintaining this pressurized state, a cooling medium such as sufficient water is continuously flowed into the cooling holes 5 in advance, and the mold is lowered to a predetermined temperature or less, so that the entire mold acts as a cold lump, and Cooling is promoted while the water-cooled mold surface and the solidified shell are in close contact with each other by pressurization, and the molten metal 6 is supercooled and solidified (see FIG. 1D). At this time, if the medium flowing into the cooling hole 5 is made to flow turbulently, the cooling ability can be improved, and thus a further rapid cooling effect can be obtained. As an example of such a medium, the Reynolds coefficient is preferably 5000 or more, and 12000 to 20000 is preferable. In order to complement these, a water flow hole shape and a water flow arrangement shape can be cited as an efficient design of the water channel along the inner space of the mold. In FIG. 1, the cross-sectional shape of the cooling hole 5 is circular, but the cooling hole is arranged in a quadrangular shape to increase the Reynolds coefficient, and the inner surface roughness of the cooling hole 5 is increased. By increasing it, the fluid viscosity coefficient can be increased and the cooling performance can be improved. In addition, the cooling capacity can be improved by appropriately increasing the number of the cooling holes 5 or increasing the pressure.

  After the solidification of the molten metal 6 in the high-pressure casting mold 1 is completed and the preform 7 is formed, the high-pressure casting mold 1 is opened (see FIG. 1 (e)), and the preform 7 is taken out (see FIG. 1E). (Refer FIG.1 (f)).

(Rolling process)
Finally, although not shown, the outer peripheral surface of the cylindrical portion 7a of the preform 7 is rolled to a predetermined shape (for example, spinning), thereby completing the vehicle wheel. In this rolling, processing in a state in which the temperature of the preform is maintained at a predetermined temperature equal to or lower than the recrystallization temperature of the preform (warm processing), or the temperature of the preform is equal to or higher than the predetermined recrystallization temperature of the preform. Processing (hot processing) while maintaining the temperature is performed. Further, in both rolling processes, both warm processing and hot processing, a preform is used by using a rolling tool (for example, a mandrel roll, a roller, etc.) heated and maintained at a temperature approximate to the preform temperature. It is freed from the sequential increase of deformation resistance due to the cooling of the material, and the freedom of formability is improved.

  According to the present embodiment, the preform 7 made of the material of the supersaturated α phase and the dense / fine structure can be formed by supercooling and solidifying the molten metal 6. Therefore, since the preform 7 is formed from a material in which the crystal grains are refined, the preform 7 exhibits a high uniform elongation in plastic working, and a large spreadability is obtained. That is, according to the present embodiment, it is possible to provide a manufacturing method capable of dramatically improving the forming ability of the vehicle wheel preform 7 in the rolling process as compared with the conventional case.

  Further, since the molten metal 6 exiting the melting furnace is supplied into the high pressure casting mold 1 without being exposed to air, the molten metal is contaminated by the inclusion of oxides, nitrides, fractured solidified grains accompanied by cracks, and the like. Absent. As a result, the molten metal 6 is made of a material that does not contaminate the molten metal such as oxides and fractured solidified grains in terms of quality, and when the preform 7 is rolled, the temperature of the preform 7 is a predetermined temperature lower than the recrystallization temperature of the preform 7. Since processing is performed in a state in which the temperature is maintained (warm processing) or processing in which the temperature of the preform 7 is maintained at a predetermined temperature equal to or higher than the recrystallization temperature of the preform 7 (hot processing), rolling It is possible to provide a vehicle wheel manufacturing method in which the forming ability of the vehicle wheel preform 7 in the process is further improved.

  In addition, the high pressure casting mold 1 is made of a Cu—Ni—Si ternary hard copper alloy having a high heat transfer coefficient, and the total volume of the high pressure casting mold 1 is at least three times the volume of the preform 7. The cooling hole 5 formed along the internal space of the high-pressure casting mold 1 is formed inside the mold body, so that hot water is supplied to the internal space of the high-pressure casting mold 1. The molten metal 6 can be made dense and fine by reliably supercooling. As a result, superplastic deformation can be reliably expressed with respect to the material constituting the molten metal 6.

  Further, when the molten metal 6 is supercooled and solidified, if the medium flowing through the cooling hole 5 is controlled to flow in a turbulent flow having a Reynolds coefficient of 5000 or more, it can be more easily introduced into the internal space of the high pressure casting mold 1 by the cooling effect. The molten metal 6 supplied with hot water can be supercooled.

  Further, in the preform molding step, before the molten metal 6 is supplied to the internal space of the high pressure casting mold 1, the internal space of the high pressure casting mold 1 is decompressed and filled with an inert gas in advance. Since the molten metal 6 can be prevented from being oxidized, the molten metal 6 supplied to the internal space of the high-pressure casting mold 1 can be reliably maintained with high purity, and the internal quality and the casting surface can be improved.

<Modification of First Embodiment>
Next, the manufacturing method of the vehicle wheel which concerns on the modification of 1st Embodiment of this invention is demonstrated. Note that description of the same parts as in the first embodiment may be omitted.

  The vehicle wheel manufacturing method of the present modification is different from the first embodiment in that it includes a pre-straining step for performing pre-straining between the preform forming step and the rolling step in the first embodiment. The other steps are the same as those in the first embodiment.

  Pre-strain (cold to hot) processing gives 3% to 25% cold upsetting pre-strain to the preform structure obtained in the same process as the preform molding process of the first embodiment. In the heat treatment process before the rolling process, the cast structure of the preform is decomposed and refined. A pre-strain of less than 3% is not preferable because the effect of decomposition and refinement can hardly be obtained. Further, pre-strain exceeding 25% is not preferable because it may cause cracks.

  According to this modification, the same effects as those of the first embodiment can be obtained, and the preform structure can be decomposed and refined in the rolling process, so that the preformability of the vehicle wheel preform is further improved. A method for manufacturing a vehicle wheel can be provided.

<Second Embodiment>
Next, a method for manufacturing a vehicle wheel according to the second embodiment of the present invention will be described. FIG. 2 is a schematic view showing a part of the manufacturing process in the method for manufacturing a vehicle wheel according to the second embodiment of the present invention. Note that description of the same parts as in the first embodiment may be omitted.

  The vehicle wheel manufacturing method according to the present embodiment is equal in temperature to the preform 8 heated and held at a temperature at which superplastic working is possible between the preform forming step and the rolling step in the first embodiment. The second embodiment is different from the first embodiment only in that it has a forging process for forging the preform 8 using the mold 9 heated and held in the first embodiment. It is the same.

  Next, the forging process will be specifically described. As shown in FIG. 2, after the preform 8 obtained in the same process as the preform molding process in the first embodiment is heated and held at a temperature at which superplastic processing is possible, the temperature is equal to the preform 8. The mold 9 is clamped by being sandwiched between the upper mold 9a and the lower mold 9b that are heated and held so as to be forged. 2, 10a and 10b are heat insulating plates, 11 is a heater, 12a and 12b are heat insulating plate water cooling holes, 13 is a flash gutta, and 14 is a cooling plate. Examples of the heat insulating plates 10a and 10b include ceramic plates with high high temperature creep strength. Examples of the heater 11 include a cartridge heater, and any heater may be used as long as the mold 9 can be heated to a high temperature (for example, about 600 ° C.). However, since a die incorporating a heater usually uses a heat-treated hot tool steel, the heater die is heated when exposed to a temperature higher than the tempering temperature of the tool steel (eg, 600 ° C.) for a long time. Mold life is deteriorated due to softening and decarburization of the contact surface. For this reason, a large number of PSZ (partially stabilized zirconia) ceramic thin short rings are mounted between the heater and the mold hole to provide flexibility, and the temperature gradient to the mold is controlled slowly. However, this does not apply to a heat-resistant superalloy material that does not change in high-temperature strength and hardness from room temperature to approximately 800 ° C.

  For example, in the case where the preform 8 is made of a medium-strength aluminum alloy, although it largely depends on the crystal grain size and strain rate, the dominant molding temperature can be superplastically processed at approximately 400 to 500 ° C. Industrial temperature range. Therefore, various materials can be superplastically forged by appropriately setting the temperatures of the preform 8 and the mold 9.

  Even when the preform 8 and the mold 9 are equally heated and maintained at the superplastic working temperature, the crystal grain size of the preform 8 is relatively large, approximately 100 to 150 μm. If it exceeds, superplastic deformation may not occur. However, even if superplastic deformation does not occur, the high-temperature deformation resistance of the preform 8 is small because it is heated and held substantially in the high-temperature region, and a large deformability can be obtained. This is because the effect of refining crystal grains is slow compared to that during superplastic deformation.

  According to this embodiment, the same effect as that of the first embodiment can be obtained. In addition, since the preform 8 is heated and held at a temperature at which superplastic working is possible, dislocations within the grain boundaries and grains are easy to move. Therefore, during forging, the fine crystal grains of the supercooling material can cause plastic flow accompanied by large-scale grain boundary sliding, so that the forging pressure is reduced and the forging portion of the preform 8 is simultaneously produced. The (cylindrical portion 8a) can be greatly extended. That is, it is possible to refine the material structure of the preform 8 by molding, improve the quality characteristics of the material constituting the preform 8, and perform precise forging of the complex shape of the preform 8. Therefore, it is possible to provide a method for manufacturing a vehicle wheel that can reliably obtain a net-shaped vehicle wheel having quality characteristics equivalent to or better than those of conventional products.

<Third Embodiment>
Next, a method for manufacturing a vehicle wheel according to the third embodiment of the present invention will be described. In addition, about the part similar to 1st Embodiment, description may be abbreviate | omitted as a code | symbol which represented the tenth place by 2 and represented the first place by the same number.

  First, the high-pressure casting mold 21 is prepared in an opened state (see FIG. 3A). Subsequently, the upper mold 21a and the lower mold 21b are clamped, and the spacer plates (holding means) 27a and 27b are sandwiched between the upper mold 21a and the lower mold 21b. At this time, the internal space of the high pressure casting mold 21 is maintained at a predetermined temperature or lower. Then, a laminar flow is supplied from the melting furnace (not shown) through the hot water supply pipe 22 into the pressurizing cylinder 23 using the air pressure without touching the air. Then, the pressure plunger 24 is raised along the inside of the pressure cylinder 23, and the pressure of the melting furnace is lowered in a state where the communication portion between the hot water supply pipe 22 and the pressure cylinder 23 is closed by the pressure plunger 24. Then, the molten metal level of the hot water supply pipe 22 is lowered to the standby level (see FIG. 3B). At this time, the internal space of the high pressure casting mold 21 may be preliminarily decompressed and then filled with an inert gas.

  Next, the pressure plunger 24 is moved in the direction of the high pressure casting mold 21 to fill the internal space of the high pressure casting mold 21 with the molten metal 26, and then the molten metal 26 is pressurized (about 80 MPa to about 200 MPa). While maintaining this pressurized state, a cooling medium such as sufficient water is continuously flowed into the cooling hole 25 in advance, and the mold is lowered to a predetermined temperature or lower so that the entire mold acts as a cold lump, and Cooling is promoted while the water-cooled mold surface and the solidified shell are in close contact with each other, and the molten metal 26 is supercooled and solidified (see FIG. 3C).

  After the solidification of the molten metal 26 in the high pressure casting mold 21 is completed and the preform 28 is molded, the pressure plunger 24 is moved away from the high pressure casting mold 21 and the preform 28 and the high pressure casting mold 21 are separated. A predetermined space surrounded by 21 and the pressure plunger 24 is formed, and the spacer plates 27a and 27b are removed from between the upper mold 21a and the lower mold 21b (see FIG. 3D).

  Then, the upper mold 21a and the lower mold 21b are clamped so as to push the preform 28 into the predetermined space, and the preform 28 is forged (see FIG. 3E). At this time, the pressure plunger 24 is supported by a member (not shown) so as not to move away from the high pressure casting mold 21. Thereafter, the high pressure casting mold 21 is opened and the preform 28 is taken out.

  In the rolling process, the same process as in the first embodiment is performed. Thereby, the vehicle wheel using the manufacturing method of this embodiment is completed (not shown).

  According to the present embodiment, it is possible to provide a method for forging a predetermined material for a vehicle wheel immediately after high-pressure casting, and it is possible to achieve the same effect as that of the first embodiment.

  Here, in this embodiment, although each process was implemented cooling the metal mold | die, you may perform each process, without cooling a metal mold | die. However, at this time, the same effect as the first embodiment cannot be obtained.

<Fourth embodiment>
Next, a vehicle wheel manufacturing method according to a fourth embodiment of the present invention will be described. In addition, about the part similar to the part of 2-6 of 1st Embodiment, the code | symbol of 32-36 may be attached in order and description may be abbreviate | omitted.

  As shown in FIGS. 4A to 4E, the mold 31 has an upper mold 31 a, a lower mold 31 b, and a punch 37. The punch 37 is fitted in a through hole formed in a substantially central portion of the upper mold 31a so as to be movable in the axial direction. Although not shown, a press device capable of applying a predetermined pressure in the axial direction is installed at one end of the punch 37 opposite to the inside of the die 31.

  Next, a method for manufacturing a vehicle wheel according to the fourth embodiment of the present invention will be specifically described. First, the die 31 for high pressure casting is prepared in a state where the die is opened (see FIG. 4A). Subsequently, the upper die 31a and the lower die 31b are clamped in a state where the punch 37 is temporarily fixed and supported at a predetermined position of the upper die 31a, and the spacer plates (holding means) 38a and 38b are attached to the upper die. It is sandwiched between the mold 31a and the lower mold 31b. At this time, the internal space of the high pressure casting mold 31 is maintained at a predetermined temperature or lower. Then, a laminar flow is supplied from the melting furnace (not shown) through the hot water supply pipe 32 into the pressurizing cylinder 33 using the air pressure without touching the air. Then, the pressurization plunger 34 is raised along the inside of the pressurization cylinder 33, and the pressure of the melting furnace is lowered with the communication portion between the hot water supply pipe 32 and the pressurization cylinder 33 closed by the pressurization plunger 34. Then, the molten metal level of the hot water supply pipe 32 is lowered to the standby level (see FIG. 4B). At this time, the internal space of the high pressure casting mold 31 may be preliminarily decompressed and then filled with an inert gas.

  Next, the pressure plunger 34 is moved in the direction of the high pressure casting mold 31 to fill the internal space of the high pressure casting mold 31 with the molten metal 36, and then the molten metal 36 is pressurized (about 80 MPa to about 200 MPa). While maintaining this pressurized state, a cooling medium such as sufficient water is continuously flowed into the cooling hole 35 in advance, and the mold is lowered to a predetermined temperature or lower so that the entire mold acts as a cold lump, and Cooling is promoted while the water-cooled mold surface and the solidified shell are in close contact with each other, and the molten metal 36 is supercooled and solidified (see FIG. 4C).

  After solidification of the molten metal 36 in the high pressure casting mold 31 is completed and the preform 38 is formed, the pressure plunger 34 is fixedly supported and the punch 37 is released. Then, the spacer plates 37a and 37b are removed from between the upper mold 31a and the lower mold 31b (see FIG. 4D).

  Subsequently, the upper mold 31a and the lower mold 31b are clamped. At this time, using the above-described press device (not shown), the preform 38 is pressed into the space formed by the upper die 31a and the moved punch 37, and the punch 37 is pressed against the punch 37 in FIG. Control is performed so that the punch 37 gradually moves upward in FIG. 4E while applying a predetermined force in the downward direction. This control is performed until the upper die 31a and the punch 37 are in a predetermined positional relationship, and then the preform 38 is forged while being fixedly supported so as not to move (FIG. 4 (e)). )reference). Thereafter, the high pressure casting mold 31 is opened and the preform 38 is taken out.

  In the rolling process, the same process as in the first embodiment is performed. Thereby, the vehicle wheel using the manufacturing method of this embodiment is completed (not shown).

  According to the present embodiment, it is possible to provide a method for forging a predetermined material for a vehicle wheel immediately after high-pressure casting, and it is possible to achieve the same effect as that of the first embodiment.

  Here, in this embodiment, although each process was implemented cooling the metal mold | die, you may perform each process, without cooling a metal mold | die. However, at this time, the same effect as the first embodiment cannot be obtained.

  The present invention can be changed in design without departing from the scope of the claims, and is not limited to the above-described embodiments and modifications. For example, in the second embodiment, the predistortion process in the modification of the first embodiment may be performed before or after the forging process.

  Also, instead of the forging step in the second embodiment, (a) a mold heated and held so that the temperature is equal to the preform heated and held in a hot temperature region above the recrystallization temperature. And (b) the preform heated and held in a warm temperature region below the recrystallization temperature between the preform forming step and the rolling step. A vehicle wheel manufacturing method that uses any one of the forging processes in which the preform is forged using a mold heated and held so that the temperatures are equal may be used. Also in these manufacturing methods, preform forming ability that is similar to or equal to or higher than that of the conventional one can be easily obtained.

It is the schematic diagram which showed in order the manufacturing process in the manufacturing method of the vehicle wheel which concerns on 1st Embodiment of this invention. It is the schematic diagram which showed a part of manufacturing process in the manufacturing method of the vehicle wheel which concerns on 2nd Embodiment of this invention. It is the schematic diagram which showed a part of manufacturing process in the manufacturing method of the vehicle wheel which concerns on 3rd Embodiment of this invention, Comprising: It is a figure which shows before the mold clamping of the metal mold | die for high pressure casting. It is a figure which shows the middle of performing the mold clamping of the high pressure casting mold after the process of Fig.3 (a), and pouring the molten metal in the high pressure casting mold. It is a figure which shows just before solidifying a molten metal after the process of FIG.3 (b). It is a figure which shows the state which removed the spacer plate while forming the preform by solidifying a molten metal after the process of FIG.3 (c), forming a predetermined space in the metal mold | die for high pressure casting. FIG. 4 is a diagram showing a state in which a high pressure casting mold is clamped and a preform is pushed into a predetermined space in the high pressure casting mold after the step of FIG. It is the schematic diagram which showed a part of manufacturing process in the manufacturing method of the vehicle wheel which concerns on 4th Embodiment of this invention, Comprising: It is a figure which shows before the mold clamping of the metal mold | die for high pressure casting. FIG. 5 is a view showing a state in which the high pressure casting mold is clamped after the step of FIG. 4A and the molten metal is poured into the high pressure casting mold. FIG. 5 is a diagram showing a state immediately before the molten metal is solidified after the step of FIG. FIG. 5 is a view showing a state in which a molten metal is solidified to form a preform after the step of FIG. 4C, a predetermined space is formed in a high-pressure casting mold, and a spacer plate is removed. FIG. 5 is a diagram showing a state in which a high-pressure casting mold is clamped and a preform is pushed into a predetermined space in the high-pressure casting mold after the step of FIG.

Explanation of symbols

1, 21, 31 High pressure casting molds 1a, 9a, 21a, 31a Upper molds 1b, 9b, 21b, 31b Lower molds 2, 22, 32 Hot water supply pipes 3, 23, 33 Pressure cylinders 4, 24, 34 Pressure plunger 5, 25, 35 Cooling hole 6, 26, 36 Molten metal 7, 8, 28, 39 Preform 7a, 8a Cylindrical part 9 Mold 10a, 10b Heat insulation plate 11 Heater 12a, 12b Heat insulation plate Water cooling hole 13 Gutter 14 Cooling plates 27a, 27b, 38a, 38b Spacer plate 37 Punch

Claims (16)

High pressure casting mold for forming a preform having a plurality of mold members forming an internal space, having a cylindrical portion and a disk portion, and having an axial cross-sectional shape that is substantially concave or substantially H-shaped A vehicle wheel manufacturing method having a preform molding process using
The high-pressure casting mold has a holding means that can hold the inner space wider than the inner space after clamping and is detachable;
A step of attaching the holding means before casting the preform with the high-pressure casting mold, removing the holding means after casting the preform, and then clamping the high-pressure casting mold. A method for manufacturing a vehicle wheel, comprising:   While supplying a molten metal to an internal space of a high pressure casting mold for forming a preform having a cylindrical part and a disk part and having an axial cross-sectional shape of a substantially concave shape or a substantially H shape, pressurizing the molten metal After forming a cast preform by solid phase formation, a plastic deformation is performed so that a space is formed in a predetermined portion of the internal space of the high-pressure casting mold, and the cast preform is pushed into the space of the predetermined portion while being pressurized. A method for manufacturing a vehicle wheel, comprising: a preform forming step of forming a preform of the vehicle wheel by forging by forming the preform.   The vehicle wheel manufacturing method according to claim 1, further comprising a rolling step of rolling the outer peripheral surface of the cylindrical portion of the preform to a predetermined shape after the preform forming step.   The vehicle wheel according to any one of claims 1 to 3, wherein when forming the cast preform in the preform molding step, the molten metal is supercooled and solidified while being pressurized and forcibly cooled. Production method. After supplying the molten metal to the internal space of a high pressure casting mold for forming a preform having a cylindrical part and a disk part and having an axial cross-sectional shape that is substantially concave or substantially H-shaped, A preform molding process for molding a preform composed of a material of a supersaturated α phase and a dense and refined structure by supercooling and solidifying while forced cooling;
A rolling method for rolling the outer peripheral surface of the cylindrical portion of the preform to a predetermined shape. In the preform molding process, the molten metal is hot-charged so as not to contaminate the molten metal, and before the molten metal is supplied to the internal space of the high-pressure casting mold, The internal space is cooled and held below a predetermined temperature,
6. The method for manufacturing a vehicle wheel according to claim 4 or 5, wherein, in the rolling step, rolling is performed in a state where the temperature of the preform is maintained at a predetermined temperature equal to or lower than a recrystallization temperature of the preform. . In the preform molding process, the molten metal is hot-charged so as not to contaminate the molten metal, and before the molten metal is supplied to the internal space of the high-pressure casting mold, The internal space is cooled and held below a predetermined temperature,
The method for manufacturing a vehicle wheel according to claim 4 or 5, wherein, in the rolling step, rolling is performed in a state where a temperature of the preform is maintained at a predetermined temperature equal to or higher than a recrystallization temperature of the preform. .   In the rolling step, a jig for rolling is used which is heated and held so that the temperature is equal to the preform heated and held at a predetermined temperature equal to or higher than the recrystallization temperature of the preform. A method for manufacturing a vehicle wheel according to claim 4 or 5.   In the rolling step, a jig for rolling is used which is heated and held so that the temperature is equal to the preform heated and held at a predetermined temperature lower than the recrystallization temperature of the preform. A method for manufacturing a vehicle wheel according to claim 4 or 5. The high-pressure casting mold is formed using a Cu-Ni-Si ternary hard copper alloy so as to have a total volume of at least three times the volume of the preform,
The vehicle wheel manufacturing method according to any one of claims 4 to 9, wherein at least one cooling hole formed along the internal space is provided inside the mold body.   The method for manufacturing a vehicle wheel according to claim 10, wherein the medium flowing through the cooling hole is turbulently flowed during the supercooling and solidification.   The pre-straining step of applying pre-strain to the disk portion of the preform that has been high-pressure cast is provided between the preform molding step and the rolling step. The manufacturing method of the vehicle wheel of description.   Between the preform molding step and the rolling step, using a mold heated and held so that the temperature is equal to the preform heated and held at a temperature capable of superplastic processing, The vehicle wheel manufacturing method according to claim 5, further comprising a forging step of superplastic forging the preform.   Between the preform molding step and the rolling step, a mold heated and held so that the temperature is equal to the preform heated and held in a hot temperature region above the recrystallization temperature is used. The method for manufacturing a vehicle wheel according to any one of claims 5 to 12, further comprising a forging step of forging the preform.   Between the preform forming step and the rolling step, a mold heated and held so that the temperature is equal to the preform heated and held in a warm temperature region below the recrystallization temperature is used. The method for manufacturing a vehicle wheel according to any one of claims 5 to 12, further comprising a forging step of forging the preform. In the preform molding step, before supplying the molten metal to the internal space of the high-pressure casting mold, the internal space of the high-pressure casting mold is preliminarily decompressed and filled with an inert gas, or The internal space of the high pressure casting mold is depressurized, or the internal space of the high pressure casting mold is filled with an inert gas, according to any one of claims 1 to 15. A method for manufacturing a vehicle wheel.

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