Two-piece/full face sheet metal disk wheel

Abstract: The present invention relates to a two-piece/full face sheet metal disk wheel including a disk with a full-face structure which utilizes an outer peripheral portion of the disk as a front-side flange of a rim. This wheel includes the rim (1), and the disk (2) having the outer peripheral portion (10) radially separated into an outer portion (10a) and an inner portion (10b), wherein the outer portion (10a) forms the front-side flange (4) of the rim (1) and the inner portion (10b) forms an engagement portion (6) for the rim (1), and that the engagement portion (6) is engaged with and welded at the position of an inner peripheral surface (5) on an inner side of an outer-side bead seat of the rim (1).

Description: The present invention relates in a first aspect to a method of manufacturing a two-piece/full face metal disk wheel including a rim and a disk with a full-face structure which utilizes an outer peripheral portion of the disk as an outboard tire bead retaining flange, the method comprising the steps of: (a) forming the disk with said outboard tire bead retaining flange and with an engagement portion for the rim; and (b) engaging said engagement portion with an inner peripheral surface of said rim, and welding said rim to said disk. And in a second aspect the present invention relates to a method of manufacturing a two-piece/full face metal disk wheel including a rim and a disk with a full-face structure which utilizes an outer peripheral portion of the disk as an outboard tire bead retaining flange, the method comprising the steps of: (a) forming the disk with an engagement portion for the rim and with said outboard tire bead retaining flange by cutting and removing a part of a previously formed retaining flange portion of a greater thickness than that of the retaining flange; and (b) engaging said engagement portion with an inner peripheral surface of said rim, and welding said rim to said disk. More generally, the present invention relates to a method of manufacturing a disk wheel for an automobile, and more particularly, to a method of manufacturing a two-piece/full face sheet metal disk wheel. According to the prior art two-piece/full face sheet metal disk wheels each including a disk with a full face structure which utilizes an outer peripheral portion of the disk as a front-side flange of a rim, may be classified in two types such as an in-turned flange type and a male-female type. The wheel of the former in-turned flange type generally includes an in-turned flange 15 for prevention of a decrease in strength of a rim portion by welding, as designated by reference numeral 14 in Fig. 5. A two-piece/full face sheet metal disk wheel of the in-turned flange type is disclosed in US-A-4 610 482, wherein an unsymmetrical rim 12 of a single-sided flange type as shown here in Fig. 6 and a disk 13 illustrated here in Fig. 7 are centered and fixed to each other by means of a temporary assembling fixture. Under such condition, the disk and the rim are welded to each other at a portion represented by the reference 14 in Fig. 5. The unsymmetrical rim 12 of Fig. 6 is manufactured by means of the well-known conventional roll forming. In the two-piece/full face sheet metal disk wheel of the latter male-female type, for the purpose of facilitating positioning when the rim and the disk are assembled and welded to each other, the rim and the disk are made to act as a male member and as a female member (the male-female type), respectively, and fitted to each other (see Fig. 8). The rim 18 used in this male-female type two-piece/full face sheet metal disk wheel includes an engagement portion formed by cutting for removing a front-side flange portion 24 of the rim produced for use in the two-piece disk wheel by the well-known conventional roll forming, as illustrated in Fig. 9. In the disk 19, as shown in Fig. 10, a portion indicated by reference numeral 25 of a plate material which has been pressed, is cut and removed to thereby form an engagement portion 22. The engagement portion 22 of the disk 19 is fitted in the engagement portion 21 of the rim 18. Subsequently, the rim 18 and the disk 19 are welded to each other, as depicted by reference numeral 20. During welding, a fixture is used for fixedly retaining the rim 18 and the disk 19. In the above-described prior art, the former example, that is, the two-piece/full face sheet metal disk wheel of the in-turned flange type has such advantages that a convex portion formed by weld metal can be minimized in size and that a sufficient depth of weld penetration and a welding strength can readily be ensured, because a V-groove is defined in the welding portion 14 between the rim 12 and the disk 13. On the other hand, however, it includes a serious defect such that it is difficult to ensure an accuracy in positioning the axial centers of the rim 12 and the disk 13 by means of the fixture and to prevent distortion by heat during welding. As a result, it is also hard to steadily obtain accuracy of runout of the wheel. In the latter example, i.e., the two-piece/full face sheet metal disk wheel of the male-female type, because the engagement portion 21 of the rim 18 and the engagement portion 22 of the disk 19 respectively have small distances in a horizontal direction of the drawings, an engagement tolerance with a high accuracy is required in both engagement portions. More specifically, if they are too tight with respect to each other, they cannot often be engaged with each other. If they are engaged with each other loosely, a centering accuracy is decreased, so that distortion caused by heat during welding cannot be prevented effectively. Also, this type of wheel has such problems that the fixture is required when assembling and welding the rim and the disk, and that a surface of the welding bead 20 must be finished by grinding. Moreover, in the case where the V-groove is provided in the welding portion through such processing as cutting in order to reduce the welding bead to have a size as small as possible and to ensure the weld penetration, a defect of burn through is liable to occur during welding. Furthermore, US-A-3 611 535 discloses a method of manufacturing a two-piece/full face metal disk wheel according to the first and second types of the present invention mentioned in the beginning and defined in the preambles of claims 1 and 2. In contrast to the present invention for the method according to document US-A-3 611 535 the following steps are specific: (1) The disk is formed by casting the same from non-ferrous light metal such as magnesium, aluminum or structural alloys thereof in a disc mold, with inserting in said disc mold adjacent to the outer periphery of the mold cavity a steel ring having a radially extending surface with a portion thereof covered by a wall of the mold cavity to prevent engulfment thereof by the molten metal so that said ring forms a welding anchor. (2) The engagement portion is formed as a side surface of a groove during casting of the disk by inserting an annular ring-like core (not shown) in the mold cavity or by machining the groove in the inboard face subsequent to casting. (3) The inboard radial face of the ring provided as a welcing anchor is friction welded to the edge of the rim. This method according to US-A-3 611 535 is problematic particularly in that the maximum number of disks which can be cast with one mold set is relatively restricted, the cycle time for producing one disk by casting is relatively long, and the costs of the non-ferrous light metal are relatively high. Therefore, it is an object of the present invention to provide a method of manufacturing a two-piece/full face sheet metal disk wheel which can solve the aforementioned problems of the prior art. This object is obtained by a method according the first aspect mentioned in the beginning and defined in the preamble of claim 1, which method is characterized by the following steps: (1) forming said disk from sheet metal material such that its outer peripheral portion has a plate-like shape extending in a direction perpendicular to the axial line of the disk; (2) notching said outer peripheral portion radially such that said outer peripheral portion is separated into an axially outer portion and an axially inner portion; (3) forming said outer portion into said outboard tire bead retaining flange by bending, (4) forming said inner portion into said engagement portion by bending it axially inwardly; and (5) welding said engagement portion at the end thereof to said inner peripheral surface of the rim. The above object is also obtained by a method according to the second aspect mentioned in the beginning and defined in the preamble of claim 2, which method is characterized by the following steps: (1) forming said disk from sheet metal material such that its outer peripheral portion is pre-bent as said flange portion; (2) performing said cutting and removing step such that a stepped outer peripheral portion and a corner portion is formed; (3) separating another part from said flange portion at said corner portion for forming said engagement portion; and (4) welding said engagement portion at the end thereof to said inner peripheral surface of the rim. By the method according to the invention there is obtained a two-piece/full face sheet metal disk wheel including a disk with a full-face structure which utilizes an outer peripheral portion of the disk as a front-side flange of a rim, wherein the wheel includes the rim and the disk having the outer peripheral portion radially separated into an outer portion and an inner portion, the outer portion forms the front-side flange of the rim and the inner portion forms an engagement portion for the rim, and the engagement portion is engaged with and welded to an inner peripheral surface on an inner side of an outer-side bead seat of the rim. In the two-piece/full face sheet metal disk wheel obtained by the method according to the invention, it is more preferable that the outer peripheral portion of the disk is separated into the outer portion and the inner portion by a radial notching into the desk. Further, in this two-piece/full face sheet metal disk wheel, it is more preferable that the engagement portion of the disk is engaged with and welded at the position of a fitting end portion of the rim. In these manufacturing methods, it is more preferable that the engagement portion is engaged with and welded at the position of a fitting end portion of the rim. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a vertically sectional view showing an upper half of a two-piece/full face sheet metal disk wheel manufactured by one embodiment of the method according to the present invention. Fig. 2 is a vertical sectional view illustrative of an upper half of a rim used in the wheel in Fig. 1. Figs. 3A and 3B are vertical sectional views each illustrating an upper half of a disk for use in an embodiment of the method according to the invention; Fig. 3A shows a configuration of the disk after being stamp-formed, and Fig. 3B shows a configuration of the disk after the outer peripheral portion of the disk is separated into an outer portion and an inner portion and the outer portion is formed into a flange portion and the inner portion is formed into an engagement portion. Figs. 4A and 4B indicate an example of another embodiment of the method according to the invention; Fig. 4A is a vertical sectional view of an upper half of the disk after being stamp-formed and subsequently being cut partially, and Fig. 4B is a vertical sectional view of the same after one part of the outer peripheral portion of the disk is separated and formed into an engagement portion. Fig. 5 is a vertical sectional view showing an upper half of a two-piece/full face sheet metal disk wheel which is one example of the prior art. Fig. 6 is a vertical sectional view illustrative of an upper half of a rim used in the prior example of Fig. 5. Fig. 7 is a vertical sectional view illustrative of an upper half of a disk for use in the prior example of Fig. 5. Fig. 8 is a vertical sectional view indicating an upper half of a two-piece/full face sheet metal disk wheel which is another example of the prior art. Fig. 9 is a vertical sectional view illustrating an upper half of a rim used in the prior example of Fig. 8. Fig. 10 is a vertical sectional view of a disk used in the prior example of Fig. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below more in detail, with reference to preferred embodiments of the method according to the invention. Referring to Figs. 1 to 3, reference numeral 1 designates a rim, reference 2 indicates a disk with a full-face structure which utilizes its outer peripheral portion as a front-side flange of the rim, and references 3a and 3b show welding portions between the rim 1 and the disk 2, respectively. The rim 1 is an unsymmetrical rim, as shown in Fig. 2. An engagement portion 5 on an inner side of a rim bead seat is formed to have a tapered angle 5°. The disk 2 is formed in such a manner as to be mentioned below. At first, a sheet metal material having a thickness of t is stamp-formed into a shape of Fig. 3A and an outer peripheral portion 10 of the disk is formed into a plate-like shape extending in a direction perpendicular to the axial line X-X of the disk. Subsequently, as shown in Fig. 3B, a separating roll 11 is brought into contact with the outer peripheral portion 10 to provide a notch 10c extending in the radial direction of the disk for separating the outer peripheral portion 10 into an outer portion 10a and an inner portion 10b. When the notch 10c extends to a certain degree of depth, the separating roll 11 is replaced by a roll having a different configuration for separating the outer peripheral portion more deeply as well as rolling the outer portion 10a in order to form a front-side flange designated by reference numeral 4. The inner portion 10b is thinned by spinning to be bent leftward in the drawing, to thereby form an engagement portion 6. The disk engagement portion 6 is formed to have a certain overlap width and insertion pressure between a fitting portion 5 on an inner side of the rim bead seat and itself. An unnecessary portion 9 of the disk is cut away. The engagement portion 6 of the full-face disk 2 is press-fitted in the fitting portion 5 on the inner side of the bead seat of the rim 1. Thereafter, as indicated by reference 3a in Fig. 1, the rim 1 and the disk 2 are welded to each other between the inner peripheral surface 5 and a cut end face (the innermost welding portion in the drawing) of the engagement portion 6. As occasion demands, a sealing compound is coated on the fitting end of the rim 1. In case of executing Ni-Cr plating for improvement of decoration design, the plating processing is carried out in the state of the disk sole body illustrated in Fig. 3B. After subjecting the disk sole body to the plating processing, even if the disk 2 is engaged with and welded to the rim 1 as shown in Fig. 1, because there is a sufficiently long distance from the welding portion 3a to a disk decorative surface 7, a plating film on the disk decorative surface 7 is not peeled nor discolored due to an influence by heat during welding. When it is required to further increase a strength resulted from the welding portion 3a, the rim 1 and the disk 2 are welded to each other at another fitting end portion of the rim 1 represented by reference 3b. Figs. 4A and 4B show another embodiment of the method according to the invention than illustrated in Figs. 3A and 3B. Referring to Fig. 4A, a disk 2 is provided with a flange portion 4 having a thickness of t formed by bending during stamp-forming the disk. Then, one part 4a of the flange portion 4 is cut and removed, thereby forming a stepped outer peripheral portion 30 and a corner portion 31. Subsequently, a roller 32 is brought into contact with the corner portion 31 indicated in Fig. 4B in order to separate another part 4b of the flange portion 4 from the flange portion, thereby forming an engagement portion 6 with respect to the rim 1. An object and effect of this modified example are similar to those of the above-described embodiment of the invention. Additionally, since the flange portion 4 is formed by bending during drawing in the modified example, a spring-back phenomenon during stamp-forming the disk is repressed so that an accuracy in flatness can readily be ensured. Because the two-piece/full face sheet metal disk wheel manufactured according to the method of the invention is produced in the aforesaid manner, a sufficient large distance of engagement between the rim and the disk can be obtained. As a result, a large overlap width and high insertion pressure between the rim and the disk can be attained, which eliminates a necessity of a centering fixture when assembling and welding the rim and the disk. A deterioration of an accuracy in assembling and welding the rim and disk by an error of the fixture is not caused so that the wheel can be easily mass-produced. Thermal deformation during welding, particularly, at the rim and the front-side flange portion which are liable to be deformed, can be prevented. Further, the portion 3b can be welded preferably without causing no defect such as burn through of the rim 1, thanks to an existence of the disk engagement portion 6.

Claims: A method of manufacturing a two-piece/full face metal disk wheel including a rim (1) and a disk (2) with a full-face structure which utilizes an outer peripheral portion (10) of the disk (2) as an outboard tire bead retaining flange (4), the method comprising the steps of: (a) forming the disk (2) with said outboard tire bead retaining flange (4) and with an engagement portion (6) for the rim (1); and (b) engaging said engagement portion (6) with an inner peripheral surface (5) of said rim (1), and welding said rim (1) to said disk (2); characterized by the following steps: (1) forming said disk (2) from sheet metal material such that its outer peripheral portion (10) has a plate-like shape extending in a direction perpendicular to the axial line (X-X) of the disk (2); (2) notching said outer peripheral portion (10) radially such that said outer peripheral portion (10) is separated into an axially outer portion (10a) and an axially inner portion (10b); (3) forming said outer portion (10a) into said outboard tire bead retaining flange (4) by bending, (4) forming said inner portion (10b) into said engagement portion (6) by bending it axially inwardly; and (5) welding said engagement portion (6) at the end (3a) thereof to said inner peripheral surface (5) of the rim (1). A method of manufacturing a two-piece/full face metal disk wheel including a rim (1) and a disk (2) with a full-face structure which utilizes an outer peripheral portion (10) of the disk (2) as an outboard tire bead retaining flange (4), the method comprising the steps of: (a) forming the disk (2) with an engagement portion (6) for the rim (1) and with said outboard tire bead retaining flange (4) by cutting and removing a part (4a) of a previously formed retaining flange portion of a greater thickness than that of the retaining flange (4); and (b) engaging said engagement portion (6) with an inner peripheral surface (5) of said rim (1), and welding said rim (1) to said disk (2); characterized by the following steps: (1) forming said disk (2) from sheet metal material such that its outer peripheral portion (10) is pre-bent as said flange portion; (2) performing said cutting and removing step such that a stepped outer peripheral portion (30) and a corner portion (31) is formed; (3) separating another part (4b) from said flange portion at said corner portion (31) for forming said engagement portion (6); and (4) welding said engagement portion (6) at the end (3a) thereof to said inner peripheral surface (5) of the rim (1). A method according to claim 1 or 2, characterized in that said engagement portion (6) is engaged with and further welded at a portion of a fitting end portion (3b) of said rim (1).

Inventors: IWATSUKI KEIJI, IWATSUKI, KEIJI
Applicants: CENTRAL MOTOR WHEEL CO LTD, CENTRAL MOTOR WHEEL CO., LTD.
Application year: 1992
Main classification: B60B3
IPC codes: B60B3