JP2007106285A - Manufacturing method of vehicle wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a vehicle wheel which has favorable adhesion of a film at an edge. <P>SOLUTION: In a casting process, a disk part 10 having an ornament hole and a rim part 20 are integrally casted. In a working process, a hub hole 12 and a bolt hole 13 are made in the disk part 10, and the inner and outer peripheral surfaces of the rim part 20 and the back side of the disk part 10 are cut. Then in a chamfering process, the edge E1 is chamfered which is between the inner peripheral surface of the decorative hole 11 consisting of a casting surface and the back side of the disk part 10 consisting of a cutting surface. Furthermore, the edges E2 to E5 on the design surface side is processed by barrel polishing. Then brush is polished by a rotating brush 54, and the edge E1 is polished. Finally, painting is performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a vehicle wheel made of a light alloy such as aluminum by casting, and more particularly to a step of polishing a cast wheel and a brush polishing machine used in this step.

Patent Document 1 discloses painting a cast aluminum vehicle wheel. It is also disclosed that the coating film may not be satisfactorily adhered to the spoke edge or the like during this coating, and there is a problem that rust occurs due to long-term use. In patent document 1, it tries to prevent the rust generation | occurrence | production at the said edge by devising the coating material.
Japanese Patent Laid-Open No. 2-18101

As in Patent Document 1, there is a limit to preventing the generation of rust at the edge by devising the coating material.
The inventor of the present application tried to improve the adhesion of the coating film at the edge by manually buffing the edge at the boundary between the casting surface and the cutting surface. However, because of manual work, productivity is low and cost is high. In addition, the polishing was uneven, and the ratio of being judged as defective by the inspection after coating could not be reduced.

  The present applicant has previously filed a vehicle wheel manufacturing method having a process similar to the present invention for a different purpose (Japanese Patent Application No. 2004-183030).

The present invention has been made to solve the above problems, and in the vehicle wheel manufacturing method, before painting the cast vehicle wheel, a brush is applied to the decorative hole forming region on the back surface of the disk portion, and the brush is applied to the disk. The boundary edge between the inner peripheral surface of the decorative hole and the back surface of the disk portion is polished by rotating along a rotation locus centering on the central axis of the portion.
According to this method, the edge of the border between the inner peripheral surface of the decorative hole and the back surface of the disk portion is polished by brush polishing, so that productivity of the polishing process can be improved, and coating coating at the edge is eliminated by eliminating polishing variation. Can be performed satisfactorily.

The present invention further includes (a) a step of integrally casting a disc portion having a decorative hole and a rim portion, and (b) a machining step of making a hub hole and a bolt hole in the disc portion and cutting the back surface of the disc portion. And (c) a coating process, wherein a barrel polishing process and a brush polishing process are performed before the coating process, and in the brush polishing process, a decorative hole on the back surface of the disk portion is performed. A brush is applied to the forming area, and the edge of the border between the inner peripheral surface of the decorative hole and the back surface of the disk part is polished by rotating the brush along a rotation locus centering on the central axis of the disk part. And
According to this method, the edge of the design surface side of the hub hole and the bolt hole is polished by barrel polishing, and the edge of the boundary between the inner peripheral surface of the decorative hole and the back of the disk portion is polished by brush polishing. Productivity can be improved, and coating variations at the edges can be satisfactorily performed without variations in polishing.

The present invention further includes (a) a step of integrally casting a disc portion having a decorative hole and a rim portion, and (b) a machining step of making a hub hole and a bolt hole in the disc portion and cutting the back surface of the disc portion. And (c) a painting process, in a vehicle wheel manufacturing method,
Before the painting process, a brush polishing process is performed. In the brush polishing process, the brush is applied to the decorative hole forming area on the back surface of the disk part, and the brush is rotated along a rotation locus centering on the central axis of the disk part. By polishing, the edge of the boundary between the inner peripheral surface of the decorative hole and the back surface of the disk portion is polished, and a brush is applied to the design surface of the disk portion, and the brush follows a rotation locus centering on the central axis of the disk portion. The edge of the boundary between the inner peripheral surface of the hub hole and the bolt hole and the disk portion design surface is polished.
According to this method, the edge of the design surface side of the hub hole or the bolt hole is polished by brush polishing on the design surface side, and the edge of the boundary between the inner peripheral surface of the decorative hole and the back surface of the disk part is polished by brush polishing on the back surface side. Since the polishing is performed, the productivity of the polishing process can be improved, and variations in the polishing can be eliminated and the coating film can be satisfactorily adhered to the edge.

Preferably, prior to the brushing step, a chamfering step of chamfering an edge at the boundary between the inner peripheral surface of the decorative hole made of a cast surface and the back surface of the disk part made of a cutting surface is performed.
According to this, the burden of brush polishing can be reduced.

Preferably, in brush polishing of the back surface of the disk portion, the brush is disposed so as to occupy at least the entire area of the decoration hole forming area. Thereby, brush polishing can be performed efficiently.
Preferably, the brushes are rotated in the forward and reverse directions for approximately the same time. Thereby, the edge of the boundary between the inner peripheral surface of the decoration hole and the back surface of the disk portion can be polished almost evenly.

  Preferably, the edge of the boundary between the inner peripheral surface of the decorative hole and the back surface of the disk portion is polished by the brush polishing so that the curvature radius is 0.5 mm or more, and in the coating step, the coating film at the edge Paint to a thickness of 10 microns or more. Thereby, rust generation | occurrence | production at an edge can be prevented reliably over a long period of time.

The present invention further comprises a rotating disk, a driving means for rotationally driving the rotating disk, and a brush provided on one surface of the rotating disk in a brush polishing machine for vehicle wheel polishing,
The rotating disk is accommodated on the inner side of the rim part of the wheel while being coaxial with the disk part of the wheel, and the brush is applied to at least the entire area of the decorative hole formation area on the rear surface of the wheel disk part. Is rotated to polish the edge of the border between the inner peripheral surface of the decorative hole and the back surface of the disk part.
According to this brush polishing machine, the edge of the boundary between the inner peripheral surface of the decorative hole and the back surface of the disk portion can be polished efficiently and without variation.

  Preferably, the brush includes a plurality of brush elements, and each brush element is configured by bundling a large number of filaments carrying abrasive grains with a holding member, and the holding member of the brush element is attached to and detached from the holding hole of the rotating disk. Fits in as possible. According to this, since the brush element can be exchanged, the maintenance of the brush polishing machine is simple, and good brush polishing can always be performed.

  According to the present invention, the productivity of edge processing can be increased and the edge processing can be performed without variation, so that the coating film can be satisfactorily adhered to the edge.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a vehicle wheel manufacturing method in the order of steps. First, in step S1, low pressure casting is performed by casting molten aluminum into a mold.

  The vehicle wheel 1 which has the disc part 10 and the rim | limb part 20 integrally is obtained by the said casting, as shown in FIG.2, FIG.3. At the time of casting, a plurality of decorative holes 11 are formed in the annular portion in the vicinity of the rim portion 20 in the disc portion 10. The decoration holes 11 are formed at intervals in the circumferential direction, and a portion between the decoration holes 11 is provided as a spoke portion 15. 2 and 3, the hub hole 12, the bolt hole 13, and the valve hole 14 are shown, but these holes 12 to 14 are not formed at the casting stage.

In the next step S2, burrs are formed on the outer periphery of the rim 20 generated by casting.
In the next step S3, heat treatment is performed.

In the next step S4, lathe processing and drilling are performed.
By the lathe process, the entire area of the back surface of the disk unit 10 is cut. As a result, a flat hub mounting surface 16 is formed at the center of the back surface of the disk portion 10, and burrs left on the periphery of the decorative hole 11 are also removed. Further, by this lathe process, the inner peripheral surface and the outer peripheral surface of the rim portion 20 are cut, and the rim portion 20 is dimensioned.

  By the above drilling process, a hub hole 12 is formed in the center of the disk portion 10, a plurality of bolt holes 13 are formed at intervals in the circumferential direction so as to surround the hub hole 12, and the inner periphery of one decorative hole 11 A valve hole 14 is formed from the surface to the outer peripheral surface of the rim portion 20. In addition, the design surface side of the bolt hole 13 is a nut housing recess 13a for housing a large-diameter nut.

  The cutting surface formed by the drilling and lathe processing is shown by a thick line in FIG. 3, and the remaining cast surface is shown by a thin line. The casting surface is left on the design surface of the disk portion 10 and also on the inner peripheral surface of the decorative hole 11.

  As shown in FIGS. 2 and 3, edges E1 to E5 are formed at the boundary between the casting surface and the cutting surface. The edge E <b> 1 is formed at the boundary between the inner peripheral surface of the decorative hole 11 and the back surface of the disk portion 10. The edge E <b> 2 is formed at the boundary between the inner peripheral surface of the hub hole 12 and the design surface of the disk portion 10. The edge E3 is formed at the boundary between the nut housing recess 13a and the design surface of the disk portion 10. The edge E <b> 4 is formed at the boundary between the inner peripheral surface of the valve hole 14 and the inner peripheral surface of the decorative hole 11. The edge E5 is formed at the boundary between the rim flange cutting end surface of the rim portion 20 and the design surface.

  FIG. 7 shows a cross-sectional shape of the edge E1 of the decoration hole 11 immediately after the casting step S1. By cutting the back surface of the disk part 10 to the alternate long and short dash line L1 in the lathe process, the edge E1 becomes the shape shown in FIG.

  In the next step S5, the edge E1 of the decoration hole 11 is chamfered to the one-dot chain line L2 in FIG. 8 using a pencil grinder. By this chamfering, it is possible to remove the machining burr generated by the lathe machining. The pencil grinder is a rotary tool having a polishing portion at the tip, and the chamfering is performed by moving the pencil grinder along the edge E1 of the decorative hole 11 while rotating the polishing portion by hand.

  In the chamfering step S5, only chamfering with a pencil grinder may be performed, but buffing may be performed. This buffing removes the undulation of the edge E1 (unevenness when viewed from the design surface side) caused by chamfering with a pencil grinder, and uses a tool that vibrates the shaft portion in the axial direction. The tip portion of the shaft portion of the tool has a flat shape, and a cloth buff is attached to the tip portion. While the cloth buff is applied to the surface of the chamfered edge E1 and the tool is moved along the edge E1 while being vibrated in the axial direction, buffing is performed to eliminate the waviness.

  By the chamfering step, the edge E1 has a chamfered shape as shown in FIG. At the boundary between the chamfered portion M and the casting surface and the boundary between the chamfered portion M and the back surface of the disk portion, new obtuse local edges E1 'and E1 "are newly formed.

  In the chamfering step, chamfering of the edges E2 to E5 is performed in the same manner.

  In the next step S6, barrel polishing is performed. In this embodiment, wet barrel polishing is performed. More specifically, as shown in FIG. 4, the tank 30 accommodates an abrasive 31 made of ceramic balls or the like of about several mm. The wheel 1 is fixed to the tip of the rotating shaft 35 via a chuck and is buried in the abrasive 31. The rotating shaft 35 is rotated (periodically repeats normal rotation and reverse rotation) and is given vibration. The rotating shaft 35 moves up and down and swings simultaneously with rotation and vibration.

  By the barrel polishing, the edges E2 to E5 can be sufficiently polished and rounded. However, at the edge E1 of the decorative hole 11, the local edge E1 ′ at the boundary between the chamfered portion M and the casting surface is rounded as shown in FIG. 9B, but the boundary between the chamfered portion M and the back side cutting surface is rounded. The local edge E1 "is not rounded but remains deformed.

  In the next step S7, the edge E1 is brushed. In this step, as shown in FIG. 5, a wheel holding machine 40 and a brush polishing machine 50 are used. The wheel holding machine 40 includes an annular positioning table 41 installed horizontally, and a pressing table 42 that is positioned directly above the positioning table 41 and can be moved up and down. After positioning the rim flange on the back surface side of the rim portion 20 of the wheel 1 on the positioning table 41, the wheel 1 is held by lowering the pressing table 42 and pressing the rim flange on the design surface side of the wheel 1. It has become.

  The brush grinder 50 includes a rotating shaft 51 that stands vertically on the center axis of the positioning table 41, a driving means 52 that rotationally drives the rotating shaft 41, and a rotating disk 53 that is fixed to the upper end of the rotating shaft 51. And an annular brush 54 provided in an annular region near the outer peripheral edge on the upper surface of the rotating disk 53.

  The brush 54 includes a large number of brush elements 54a shown in FIG. The brush element 54a is formed by bundling one end of a large number of filaments 54b with a base 54c (holding member). When the base 54c is detachably fitted into a holding hole 53a formed in the annular region of the rotating disk 53, the filament 54b is brought upright.

  The filament 54b is made of polyamide such as nylon (trade name), for example, and carries abrasive grains at a mixing rate of 30%. The abrasive grains are made of, for example, silicon carbide and have a count # 60 and a diameter of 1.125 mm.

  In the state where the wheel 1 is set in the wheel holder 40 as described above, the upper end of the filament 54b of the brush 54 hits the annular region where the decorative hole 11 is formed on the back surface of the disk portion 10. When the driving means 52 is driven in this state, the brush 54 rotates to polish the edge E1 of the decorative hole 11. As a result, as shown in FIG. 9C, the local edge E1 ″ is eliminated, and the processing of the edge E1 is completed. Note that the rotation of the brush 54 is performed in the forward and reverse directions for the same time. The curvature radius of the edge E1 is 0.5 mm or more and 1 mm or less, and is 0.7 mm in this embodiment.

  In the next step S8, painting is performed. More specifically, first, a base coat is applied by powder coating, a color paint (for example, silver) is applied, and a transparent top coat is finally applied. In the present embodiment, on the design surface, the thickness of the resin coating by powder coating is about 100 microns, the thickness of the color coating is about 30 microns, and the thickness of the top coating is about 30 microns, for a total of 160. It is about a micron.

  In the coating process, all coating is prohibited on the inner peripheral surface of the bolt hole 13, the nut seat, the inner peripheral surface of the hub hole 12 (except for the design surface side end), and the hub mounting surface 16. Only a thin primer coating is formed on the rim portion 20.

  By the coating process, the coating film is also attached to the edges E1 to E5 described above. Since the edges E2 to E5 are well processed and rounded by the barrel polishing, the coating film is well attached. Further, since the edge E1 is well processed by brush polishing and rounded, as shown in FIG. 9C, the coating film 60 is satisfactorily adhered and is 10 microns or more, and in this embodiment, about 20 to 30 microns. The thickness is ensured.

  As described above, since the edges E1 to E5 are covered with the coating film and the aluminum ingot is not exposed, rust generation due to long-term use can be prevented.

  The coating film 60 shown in FIG. 9C according to the present embodiment is compared with the coating films 61 and 62 shown in FIGS. 9A and 9B. A coating film 61 indicated by an imaginary line in FIG. 9A is formed when the coating process is performed after the chamfering process without passing through the barrel polishing process and the brush polishing process. Moreover, the coating film 62 shown by an imaginary line in FIG. 9B is formed when the coating process is performed without the brush polishing after the barrel polishing process. Since the coating films 61 and 62 are extremely thin or hardly formed at the local edges E1 'and E1 ", the generation of rust cannot be avoided by long-term use.

  As described above, the manual polishing process for the edges E2 to E5 can be omitted by barrel polishing, and the manual polishing process for the edge E1 can be omitted by brush polishing. Therefore, the variation in polishing was eliminated. Moreover, barrel polishing takes 3 to 4 minutes per wheel and brush polishing takes less than 2 minutes, so productivity is greatly improved compared to manual polishing (20 to 30 minutes per wheel).

  A test to be performed after the coating process will be described. The continuity test is performed by applying electrodes to the edges E1 to E5. However, since the coating films are well formed on the edges E1 to E5, the continuity test is performed. In the actual continuity test, it was 100% non-conductive. On the other hand, when buffed manually, the non-conductivity was about 80%.

  Furthermore, when a cass test was performed, the passing rate was 100% in the vehicle wheel according to the present embodiment, whereas the passing rate was about 80% when manually buffed. The cast test was performed by spraying a mixed solution of 5% salt water and 0.027% cupric chloride (dihydrate) into a test tank set at 50 ° C., and the corrosion and corrosion resistance of the test piece. Is to evaluate.

  The present invention is not limited to the above embodiment, and various forms can be adopted. For example, barrel polishing may be performed after brush polishing. With respect to the edge E1, the cross-sectional shape of FIG. 9C can be obtained only by brush polishing.

During brush polishing, the holding mechanism may hold the vehicle wheel by gripping the rim flange on the design surface side or the back surface side.
In the brush grinder, the brush element 54a may be configured to rotate on a rotating disk.
The brush may be provided in the entire area of the rotating disk instead of the annular shape.
The brush may plant a looped filament on a rotating disk.
Brush polishing can also be performed with the state of FIG.

  In the posture shown in FIG. 5, the rim flange of the vehicle wheel may be gripped by the holding mechanism, and the illustrated brush polisher may be arranged vertically to brush the design surface as well as the back surface of the vehicle wheel. In this case, the upper brush is provided in substantially the entire region of the rotating disk, polishes the design surface side, and eventually the inner peripheral surface (cutting surface) of the hub hole 12, bolt hole 13, and valve hole 14 and the design surface (casting). Polish the edge of the border with the skin surface. Therefore, barrel polishing is not necessary.

  Manual polishing may be performed in the edge processing.

It is a figure which shows the manufacturing method of the vehicle wheel which makes one Embodiment of this invention in process order. It is a front view of the vehicle wheel which passed through the process. It is a longitudinal cross-sectional view of the vehicle wheel which passed through the manufacturing process, and shows a cutting surface with a thick line. It is a schematic longitudinal cross-sectional view which shows a barrel grinding | polishing process. It is a longitudinal cross-sectional view which shows a brush grinding | polishing process. It is a front view which shows the brush element used at a brush grinding | polishing process. It is an expanded sectional view near the decoration hole edge which shows the lathe process which cuts the disk back surface. It is an expanded sectional view which shows the chamfering process in a decoration hole edge. It is an expanded sectional view of a decoration hole edge, (A) is after chamfering, (B) is after barrel polishing, (C) shows the shape after brush polishing and painting.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle wheel 10 Disc part 11 Decoration hole 12 Hub hole 13 Bolt hole 20 Rim part 50 Brush grinding machine 52 Driving means 53 Rotating disk 53a Holding recessed part 54 Brush 54a Brush element 54b Filament 54c Base (holding member)
E1-E5 edge

Claims (9)

  Before painting the cast vehicle wheel, a brush is applied to the decorative hole forming region on the back surface of the disk part, and the brush is rotated along a rotation locus centering on the central axis of the disk part, thereby A method for manufacturing a vehicle wheel, characterized by polishing an edge at a boundary between a surface and a back surface of a disk portion. (A) a step of casting the disk portion having a decorative hole and the rim portion integrally;
(B) drilling a hub hole and a bolt hole in the disk part and cutting the back surface of the disk part;
(C) a painting process;
In the vehicle wheel manufacturing method for performing
Before the coating process, a barrel polishing process and a brush polishing process are performed. In the brush polishing process, a brush is applied to the decorative hole forming region on the back surface of the disk part, and the brush rotates around the central axis of the disk part. A method of manufacturing a vehicle wheel, characterized by polishing an edge of a boundary between the inner peripheral surface of the decorative hole and the back surface of the disk portion by rotating along a locus. (A) a step of casting the disk portion having a decorative hole and the rim portion integrally;
(B) drilling a hub hole and a bolt hole in the disk part and cutting the back surface of the disk part;
(C) a painting process;
In the vehicle wheel manufacturing method for performing
Before the painting process, a brush polishing process is performed. In the brush polishing process, the brush is applied to the decorative hole forming area on the back surface of the disk part, and the brush is rotated along a rotation locus centering on the central axis of the disk part. By polishing, the edge of the boundary between the inner peripheral surface of the decorative hole and the back surface of the disk portion is polished, and a brush is applied to the design surface of the disk portion, and the brush follows a rotation locus centering on the central axis of the disk portion. The vehicle wheel manufacturing method is characterized in that the edge of the boundary between the inner peripheral surface of the hub hole and the bolt hole and the disk portion design surface is polished by rotating the wheel.   The chamfering step of chamfering the edge at the boundary between the inner peripheral surface of the decorative hole made of a cast surface and the back surface of the disk part made of a cutting surface is performed prior to the brushing step. The manufacturing method of the vehicle wheel in any one of.   The vehicle wheel manufacturing according to any one of claims 1 to 4, wherein the brush is disposed so as to occupy at least the entire area of the decoration hole forming area in brush polishing of the back surface of the disk portion. Method.   The method for manufacturing a vehicle wheel according to claim 1, wherein the brushes are rotated in the forward and reverse directions for approximately the same time.   By the brush polishing, the edge at the boundary between the inner peripheral surface of the decorative hole and the back surface of the disk portion is polished so that the curvature radius is 0.5 mm or more. In the coating process, the coating film at the edge is 10 microns. The vehicle wheel manufacturing method according to any one of claims 1 to 6, wherein the coating is performed as described above. A rotating disk, drive means for rotating the rotating disk, and a brush provided on one surface of the rotating disk,
The rotating disk is accommodated on the inner side of the rim part of the wheel while being coaxial with the disk part of the wheel, and the brush is applied to at least the entire area of the decorative hole formation area on the rear surface of the wheel disk part. A brush polishing machine for vehicle wheel polishing, characterized in that the edge of the border between the inner peripheral surface of the decorative hole and the back surface of the disk portion is polished by rotating the wheel.   The brush is composed of a large number of brush elements, and each brush element is configured by bundling a large number of filaments carrying abrasive grains with a holding member, and the holding member of the brush element is detachably fitted into the holding hole of the rotating disk. The brush grinding machine for grinding a vehicle wheel according to claim 8.

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