Vehicle wheel and manufacturing method of the same

Abstract

To lighten a weight of a vehicle wheel.SOLUTION: A vehicle wheel 1 consists of a cast integrally comprising a disc 10 and a rim 20, wherein a plurality of windows 12, 13 and spokes 14, 15 are arranged alternately in a circumferential direction on the disc 10. An annular space 30 is formed between a disc-side side wall part 23 and an outer peripheral edge part of the disc 10 in the inside in a radial direction of a disc-side bead seat part 22 in the rim 20. Thickness reduction recesses 41, 42 are formed on a back face of the disc 10. The thickness reduction recesses 41, 42 have extension parts 41a, 42a extending outside in a lateral direction to face the annular space 30.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a vehicle wheel made of a casting and having a lightweight construction, and to a manufacturing method suitable for producing the vehicle wheel. [Background technology]

[0002] Vehicle wheels made of an aluminum alloy casting having an integral disk and rim are well known. As shown in Fig. 3 of Patent Document 1, in a typical vehicle wheel made of a casting, the intersection of the disk and the rim, i.e., the area between the sidewall and the outer peripheral edge of the disk on the radially inner side of the bead seat of the rim, is filled with casting material and has a thick wall.

[0003] Patent documents 2 and 3 disclose a technique for manufacturing a vehicle wheel by casting and flow forming (spinning). In simple terms, a preform for a vehicle wheel is first cast, which has a disk and a thick rim base part integrally formed with the disk and has a shape almost equal to the final shape. The preform is then flow formed to obtain a rim close to the final shape. In this method, an annular space is formed between the sidewall part and the outer peripheral edge part of the disk on the radially inner side of the bead seat part on the disk side of the rim. This makes it possible to reduce the weight compared to the vehicle wheel having a thick bead seat part of Patent document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-8142 A [Patent Document 2] JP 2016-49543 A [Patent Document 3] WO2019 / 131849 publication Summary of the Invention [Problem to be solved by the invention]

[0005] In the vehicle wheels of Patent Documents 2 and 3, further weight reduction is desired. [Means for solving the problem]

[0006] The present invention has been made to solve the above problems, and provides a vehicle wheel made of a casting having a disk and a rim integrally formed therewith, The present invention is characterized in that an annular space is formed between the disk side sidewall portion and the outer peripheral edge portion of the disk radially inward of the disk side bead seat portion of the rim, and an outer peripheral thickness-reducing recess facing the annular space is formed on the back surface of the outer peripheral edge portion of the disk. According to this configuration, an annular space is formed radially inward of the disk-side bead seat portion, and an outer peripheral side recess is formed on the outer peripheral edge portion of the disk, thereby making it possible to further reduce the weight of the vehicle wheel.

[0007] In one embodiment, a material-removing recess is formed on the rear surface of the disk radially inward from the annular space, and the material-removing recess has an extension portion that extends radially outward, and the extension portion is provided as at least a part of the outer peripheral material-removing recess facing the annular space. According to this configuration, a thickness-reducing recess is formed on the rear surface of the disk, the radially outwardly extending portion of which becomes an outer peripheral thickness-reducing recess, thereby making it possible to achieve even further weight reduction.

[0008] In the above-described embodiment, the disk has windows and spoke portions arranged alternately in the circumferential direction, the material-reducing recess is formed on the back surface of at least one of the spoke portions, and the extension portion of the material-reducing recess is provided as at least a part of the outer circumferential material-reducing recess. This configuration is well suited to reducing the weight of vehicle wheels having windows and spokes extending to or near the outer periphery of the disc.

[0009] In the above-mentioned embodiment, a plurality of windows are formed in the disk, the radial outer ends of the plurality of windows are spaced radially inward from the annular space, the back surface of the disk has an annular surface area surrounding the plurality of windows, the material-removing recesses are formed in the annular surface area, and the extensions of the material-removing recesses are provided as at least a part of the outer peripheral material-removing recesses facing the annular space. With this configuration, the annular surface area can improve aerodynamic performance while reducing weight. Preferably, the thickness-removing recess is formed to extend in the circumferential direction, and the expansion portion of the thickness-removing recess is formed in an arc shape and faces the annular space. With this configuration, the thickness-removing recess can be formed in a wider area, thereby achieving even further weight reduction.

[0010] In another embodiment, the outer peripheral recess extends along the disk-side bead seat portion to describe a circular ring. This configuration makes it possible to further reduce the weight of the outer peripheral edge of the disk.

[0011] In another embodiment, the disk has a window forming portion including a plurality of windows between the outer peripheral edge portion and the hub portion, the window forming portion extends to the vicinity of the annular space, and the back surface of the disk is formed radially outward of the hub portion with only the outer peripheral side thickness-reducing recesses as thickness-reducing recesses. According to this configuration, it is possible to further reduce the weight of a vehicle disc in which the window formation portion is enlarged.

[0012] Another aspect of the present invention is a method for manufacturing a vehicle wheel, comprising a casting step of casting a preform for a vehicle wheel having a disk close to a final shape and a rim original part that is thicker than a rim of a final shape, and a processing step of forming a rim close to a final shape by flow forming the rim original part of the preform, In the casting process, an outer peripheral weight-removing recess is formed near the rim original portion on the back surface of the outer peripheral edge of the disk, and in the processing process, the rim original portion is flow formed radially inward to form a disk-side sidewall portion which covers the outer peripheral weight-removing recess, and at the same time, an annular space is formed between the disk-side sidewall portion and the outer peripheral edge of the disk, radially inward of the disk-side bead seat portion. According to this method, the radially inner side of the disk-side bead seat portion is not thickened, so that the weight can be reduced and casting defects such as voids can be suppressed, and since cutting is not required to form the annular space, it is possible to avoid casting defects being exposed and resulting in a defective product. Furthermore, since the outer peripheral recess is formed at the casting stage, the weight can be reduced and the cutting process for forming the outer peripheral recess can be omitted.

[0013] In the casting process, a material-removing recess may be formed on the rear surface of the disk, the material-removing recess may have an extension portion that extends radially outward, and the extension portion may be provided as at least a part of the outer peripheral material-removing recess. In this way, the vehicle wheel can be made even lighter. Effect of the Invention

[0014] According to the present invention, by forming an annular space radially inward of the disk-side bead seat portion and forming an outer peripheral side weight-reducing recess facing the annular space, it is possible to further reduce the weight of the vehicle wheel. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a front view of a vehicle wheel according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along the line II-II of FIG. [Diagram 3] FIG. [Figure 4]4 is a perspective view showing one of the material-reducing recesses formed in the spokes of the vehicle wheel. FIG. [Diagram 5] 4A is a cross-sectional view taken along line AO ​​in FIG. 3, and FIG. 4B is a cross-sectional view taken along line BO in FIG. [Figure 6] 1A and 1B are schematic diagrams showing the manufacturing process of the vehicle wheel, in which (A) is a cross-sectional view showing half of a cast vehicle wheel preform, and (B) is a cross-sectional view showing the preform set in a flow forming apparatus. [Figure 7] FIG. 6 is a front view of a vehicle wheel according to a second embodiment of the present invention; [Figure 8] FIG. [Figure 9] FIG. 2 is a rear view of the vehicle wheel, with the rim cut away at the bead seat portion on the disk side. [Figure 10] 8A is a cross-sectional view taken along line A-0 in FIG. 8, (B) is a cross-sectional view taken along line BO in FIG. 8, and (C) is a cross-sectional view taken along line CO in FIG. [Figure 11] FIG. 11 is a cross-sectional view of a vehicle wheel according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] First Embodiment A vehicle wheel 1 according to a first embodiment of the present invention will now be described with reference to Figures 1 to 6. The vehicle wheel 1 is made of an aluminum alloy, and is manufactured by casting and flow forming as described below.

[0017] <General structure of vehicle wheel> 1 to 3, a vehicle wheel includes a disc 10 and a generally cylindrical rim 20. A hub portion 11 in the center of the disc 10 is formed with a hub hole 11a and a plurality of bolt holes 11b surrounding the hub hole 11a.

[0018] As shown in Figures 1 and 3, the disk 10 has windows and spoke portions alternately arranged in the circumferential direction between the hub portion 11 and the outer circumferential edge. In this embodiment, two types of windows 12, 13 having different shapes are arranged alternately in sets of five (plural), and two types of spoke portions 14, 15 having different shapes are arranged alternately in sets of five (plural). In this embodiment, the windows 12, 13 and the spoke portions 14, 15 extend to the outer circumferential edge of the disk 10 or to the vicinity thereof. The design surface of the wide spoke portion 14 has an uneven shape.

[0019] As shown in FIG. 2, the rim 20 has, in the axial direction from the side opposite the vehicle (the disc 10 side; hereinafter referred to as the outside) to the vehicle side (hereinafter referred to as the inside), an outer flange portion 21, an outer bead seat portion 22, an outer sidewall portion 23, a drop portion 24, an inner sidewall portion 25, an inner bead seat portion 26, and an inner flange portion 27. The intersection of the drop portion 24 and the outer sidewall portion 22 is the smallest diameter portion of the rim 20. A pair of bead seats 22, 26 for supporting the bead portions of the tire have a larger diameter than the drop portion 24 and are connected to the drop portion 24 via the sidewall portions 23, 25.

[0020] <Lightweight structure> As shown in FIG. 2, an annular space 30 is formed radially inward of the outer bead seat portion 22 between the outer sidewall portion 23 and the outer peripheral edge of the disk 10 .

[0021] As shown in Figures 3 and 5, the backs of the spokes 14, 15 (the surfaces opposite the design surface) are formed with thickness-reducing recesses 41, 42, respectively. The thickness-reducing recesses 41, 42 have a width corresponding to the width of the spokes 14, 15, and a shape corresponding to the shape of the design surface. As shown in Figure 4, the thickness-reducing recess 41 has a deep portion corresponding to the convex portion of the design surface of the spoke 14.

[0022] The material-removing recesses 41, 42 are expanded radially outward from the radial position of the minimum diameter portion of the drop portion 24 (indicated by line P in Figs. 5(A) and (B)). These expanded portions are indicated by symbols 41a, 42a. The expanded portions 41a, 42a of the material-removing recesses 41, 42 are provided as outer circumferential material-removing recesses facing the annular space 30.

[0023] The vehicle wheel 1 configured as described above can be made even lighter because the intersection of the disc 10 and the rim 20 is not thickened and an annular space 30 is formed, and because weight-removing recesses 41, 42 are formed in the spoke portions 14, 15, and these weight-removing recesses 41a, 42a have extensions 41a, 42a facing the annular space 30.

[0024] <Method of manufacturing vehicle wheels> A method for manufacturing the vehicle wheel 1 having the above configuration will now be described. A vehicle wheel preform 1A shown in Fig. 6(A) is obtained by casting. This preform 1A is subjected to flow forming as shown in Fig. 6(B) to obtain a vehicle wheel 1 close to the final shape. This will be described in detail below.

[0025] The cast preform 1A has a disk 10 and a rim original part 20A that are close to their final shape. The rim original part 20A is annular and thicker than the rim 20 in its final shape, with a diameter that expands towards the tip, giving it an overall trumpet shape. The base end of the rim original part 20A is thinner and narrower than the other parts. The rim original part 20A has an outer rim flange part 21 and an outer bead seat part 22 that are close to their final shape.

[0026] 6(A), the material-removing recesses 41 of the spokes 14 extend close to the rim original part 20A, and the portion close to this rim original part 20A is provided as the above-mentioned extension 41a (outer peripheral side material-removing recess). Although not shown, the extension 42a (outer peripheral side material-removing recess) of the material-removing recesses 42 of the spokes 15 also extends close to the rim original part 20A.

[0027] The preform 1A is set in a flow forming apparatus 100, which is shown in Fig. 6(B) and subjected to flow forming. The flow forming apparatus 100 is a known apparatus, and will be briefly described as comprising a mandrel 101, a plurality of movable pieces 102 attached to the tip of the mandrel 101, and a pressure roller 103 as main components.

[0028] The outer periphery of the movable piece 102 has a profile corresponding to the shape of the outer bead seat portion 22 and the outer sidewall portion 23 of the rim 20 of the vehicle wheel 1. The outer periphery of the mandrel 101 has a profile corresponding to the shape of the drop portion 24 to the inner flange portion 27 of the rim 20 of the vehicle wheel 1. The movable pieces 102 are arranged at equal intervals in the circumferential direction and can be retreated radially inward.

[0029] In the above-mentioned set state, the movable piece 102 is in a position protruding radially outward and is in contact with the inner circumference of the outer bead seat portion 22 of the preform 1A. The flow forming process is performed while rotating the mandrel 101. In the initial stage of the flow forming process, the pressure roller 103 is moved radially inward. As a result, the pressure roller 103 and the movable piece 102 cooperate to form the outer sidewall portion 23. At the same time, an annular space 30 is formed between the outer peripheral edge of the disk 10 and the outer sidewall portion 23 on the radial inside of the bead seat portion 22. The outer sidewall portion 23 covers the extensions 41a, 42a of the material-removing recesses 41, 42, and as a result, the extensions 41a, 42a face the annular space 30.

[0030] Next, the rim original portion 20A is pressed against the outer periphery of the mandrel 101 by the pressure roller 103 to form a predetermined thickness, while the pressure roller 103 is moved axially and radially along the profile of the outer periphery of the mandrel 101, thereby flow forming the rim original portion 20A while reducing its thickness. As a result, as shown in Figures 2 and 5, the drop portion 24, inner sidewall portion 25, inner bead seat portion 26 and inner flange portion 27 are formed in sequence, and a vehicle wheel 1 having a rim 20 close to its final shape is obtained.

[0031] After the flow forming process is completed, the movable piece 102 is moved radially inwardly by using a cam mechanism or the like, and the vehicle wheel 1 is removed from the mandrel 101. After the flow forming process, the wheel is heat treated, cut, and painted to complete the vehicle wheel 1. The hub hole 11a and the bolt holes 11b may be formed before or after the flow forming process.

[0032] According to the above method, since the outer bead seat portion 22 is not thick during casting, it is possible to suppress casting defects such as voids. Also, it is possible to avoid exposure of casting defects that occur when the annular space 30 is formed by cutting. Furthermore, since it is not necessary to cut the annular space 30 or the expansion portions 41a, 42a of the recesses 41, 42 in order to reduce weight, productivity is good.

[0033] Next, a vehicle wheel according to another embodiment of the present invention will be described with reference to the drawings, in which components corresponding to those in the first embodiment are given the same reference numerals and detailed description thereof will be omitted. <Second embodiment> 7 to 10 show a vehicle wheel according to a second embodiment. The vehicle wheel 1 of this embodiment differs from the first embodiment in the shape of the window of the disc 10, the spokes, and the recessed portions on the back surface, but other components are substantially the same as those of the first embodiment.

[0034] As shown in Figures 7 and 8, a concave-convex pattern is formed on the design surface of the disc 10. As in the first embodiment, the disc 10 has windows and spoke portions arranged alternately in the circumferential direction. Two types of windows 16, 17 having different shapes are arranged alternately in the circumferential direction, five by five (plural), and two types of spoke portions 18, 19 having different shapes are arranged alternately in the circumferential direction, five by five (plural).

[0035] The radial dimension of the windows 16, 17 is shorter than that of the windows 12, 13 of the first embodiment, and their radial outer ends are spaced apart from the outer peripheral edge of the disk 10. Therefore, as shown in Figures 8 and 9, the back surface of the disk 10 has an annular surface area 10a surrounding the windows 16, 17. The outer peripheral edge of the annular surface area 10a coincides with the outer bead seat portion 22 of the rim 20. The annular surface area 10a has, on its inner circumference, substantially triangular surface area portions of different shapes that alternate in the circumferential direction.

[0036] As shown in Figs. 8 and 9, five (a plurality of) arc-shaped recesses 50 extending in the circumferential direction are formed in the annular surface area 10a on the back surface of the disk 10. Each recess 50 has two triangular recesses 51, 52 corresponding to the triangular surface area portions of the annular surface area 10a, and a recess 53 extending in the circumferential direction connecting these recesses 51, 52. The triangular recess 51 is disposed between the windows 16, 17, and its apex portion is connected to the spoke 18. The triangular recess 52 is disposed between the windows 16, 17, and its apex portion is connected to the spoke 19. The recess 53 is located radially outside the window 16.

[0037] The five arc-shaped recesses 50 each have an arc-shaped extension 50a that extends radially outward. The extension 50a extends close to the outer bead seat 22 of the rim 20, faces the annular space 30, and is hidden by the outer sidewall 23.

[0038] Furthermore, on the back surface of the disk 10, a plurality (five) of communicating recesses 55 are formed, which are disposed radially outward of the window 17 and face the annular space 20. These communicating recesses 55 are connected to the expanding portions 50a of the adjacent material-stealing recesses 50 to form an outer peripheral material-stealing recess 59 that forms a ring. In other words, the outer peripheral material-stealing recess 59 facing the annular space 30 includes the expanding portions 50a of the five material-stealing recesses 50 that extend in the circumferential direction and the communicating recesses 55.

[0039] In the second embodiment, the aerodynamic performance can be improved by reducing the opening area of ​​the outer periphery of the design surface of the vehicle wheel 1. As in the first embodiment, the annular space 30 is formed, and the weight-reducing recesses 50 are formed over a wide area in the annular surface area 10a of the back surface of the vehicle wheel 1, and the outer periphery-side weight-reducing recesses 59 facing the annular space 30 are further formed, so that the weight of the vehicle wheel 1 can be reduced.

[0040] The manufacturing method of the vehicle wheel of the second embodiment is the same as that of the first embodiment, and the vehicle wheel preform is cast and the rim original part is formed by flow forming. A material stealing recess 50 is formed on the back surface of the cast disc 10, and an outer peripheral material stealing recess 59 consisting of the extension 50a and the auxiliary recess 55 is formed close to the rim original part. The rim original part is flow formed to form the outer sidewall part 23 and at the same time form the annular space 30, and the outer peripheral material stealing recess 59 is hidden by the outer sidewall part 23 and faces the annular space 30.

[0041] <Third embodiment> In the vehicle wheel of the third embodiment shown in FIG. 11, an annular window forming portion 10x is formed between the hub portion 11 and the outer circumferential edge of the disk 10. This window forming portion 10x has a mesh shape when viewed from the front and has a large number of windows 17x. The window forming portion 10x extends to the vicinity of the annular space 30. An annular outer peripheral side material stealing recess 60 facing the annular space 30 is formed on the back surface of the outer circumferential edge of the disk 10. In this embodiment, only this outer peripheral side material stealing recess 60 is formed as a material stealing recess on the radially outer side of the hub portion 11.

[0042] The manufacturing method of the vehicle wheel of the third embodiment is the same as that of the first embodiment, and the vehicle wheel preform is cast, and the rim original part is formed by flow forming. The outer peripheral edge part of the cast disk 10 has an outer peripheral side recess 60 formed adjacent to the rim original part on the back surface. The rim original part is flow formed to form the outer sidewall part 23 and at the same time, the annular space 30 is formed, and the outer peripheral side recess 60 is hidden by the outer sidewall part 23 and faces the annular space 30.

[0043] The present invention is not limited to the above embodiment, and various other forms can be adopted. For example, in the first embodiment, the expansion portions 41a, 42a of the material-removing recesses 41, 42 may be connected by an arc-shaped recess, thereby forming an outer peripheral material-removing recess that forms a ring facing the annular space 30. In the first embodiment, the main portions of the material-removing recesses 41, 42 may be omitted, and only outer peripheral material-removing recesses corresponding to the expansion portions 41a, 42a may be formed. In the second embodiment, the communication recess 55 may be omitted, and the extensions 50a of the material-removing recess 50 may be separated from each other. Also, the extensions of the recesses 51 and 52 may be independent without forming the recess 53. Furthermore, the main portion of the material-removing recess 50 may be omitted, and only the outer peripheral side material-removing recess corresponding to the extensions 50a may be formed. In the second embodiment, the plurality of arc-shaped recessed portions may be connected together in an annular shape on the radially inner side of the annular space. In the third embodiment, a plurality of arc-shaped outer peripheral thickness-reducing recesses extending in the circumferential direction may be formed at intervals. [Industrial Applicability]

[0044] The present invention is applicable to vehicle wheels made from castings. [Explanation of symbols]

[0045] 1 Vehicle Wheel 1A Vehicle wheel preform 10 Disc 10a Annular surface area 10x window forming part 12, 13, 16, 17, 17x Windows 14, 15, 18, 19 Spokes 20 Rims 22 Outer bead seat part (disc side bead seat part) 23 Outer sidewall (disc sidewall) 24 Drop Section 30 Annular Space 41, 42 Throwing recess 41a, 42a Extension portion (outer peripheral side recess) 50 Meat-stealing recess 50a Extension portion (outer peripheral side recess) 59, 60 Outer circumference recess

Claims

1. In a vehicle wheel made of a casting having a disk and a rim integrally formed therewith, a disk-side bead seat portion of the rim having a radially inner side and a disk-side sidewall portion of the rim and an annular space is formed between the disk-side sidewall portion and an outer peripheral edge portion of the disk; The vehicle wheel is characterized in that a peripheral side recess is formed on a back surface of an outer peripheral edge portion of the disk, the recess facing the annular space.

2. A recess is formed on the rear surface of the disk radially inward from the annular space, 2. The vehicle wheel according to claim 1, wherein the recess has an extension portion that extends radially outward, the extension portion being provided as at least a portion of the outer circumferential recess facing the annular space.

3. 3. The vehicle wheel according to claim 2, wherein the disk has a plurality of windows and spoke portions arranged alternately in a circumferential direction, the material-reducing recess is formed on a back surface of at least one of the plurality of spoke portions, and the extension portion of the material-reducing recess is provided as at least a part of the outer peripheral material-reducing recess.

4. 3. The vehicle wheel according to claim 2, wherein the disk is formed with a plurality of windows, the radially outer ends of the plurality of windows being spaced radially inward from the annular space, the rear surface of the disk has an annular surface area surrounding the plurality of windows, the material-reducing recesses are formed in the annular surface area, and the extensions of the material-reducing recesses are provided as at least a portion of the outer peripheral material-reducing recesses facing the annular space.

5. 5. The vehicle wheel according to claim 4, wherein the recess is formed to extend in a circumferential direction, and the expanded portion of the recess has an arc shape facing the annular space.

6. 2. The vehicle wheel according to claim 1, wherein the outer peripheral recess extends along the disk-side bead seat portion to describe a circular ring.

7. 2. The vehicle wheel according to claim 1, wherein the disk has a window forming portion including a plurality of windows between the outer peripheral edge portion and a hub portion, the window forming portion extending to the vicinity of the annular space, and the back surface of the disk has only the outer peripheral side material-removing recesses formed as material-removing recesses radially outward from the hub portion.

8. A casting process for casting a preform for a vehicle wheel having a disk close to a final shape and a rim original part having a thickness greater than that of a rim having a final shape, the preform being integral with the disk; a processing step of forming a rim close to a final shape by flow forming the rim original part of the preform; 1. A method for manufacturing a vehicle wheel comprising: In the casting process, a peripheral side recess is formed on the back surface of the peripheral edge of the disk near the rim original portion, a disk-side sidewall portion that covers the outer peripheral thickness-removing recess by flow forming the rim original portion radially inward, and at the same time, an annular space is formed between the disk-side sidewall portion and the outer peripheral edge portion of the disk, radially inside a disk-side bead seat portion.

9. 9. The method for manufacturing a vehicle wheel according to claim 8, wherein in the casting process, a material-removing recess is formed on the rear surface of the disk, the material-removing recess has an extension portion that is extended radially outward, and the extension portion is provided as at least a part of the outer peripheral material-removing recess.

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