wheel for a vehicle

Abstract

Wheel for a vehicle, wherein the wheel has a rim (2) with a recessed section (2c) and a disc (10) formed in one piece from sheet material, wherein the rim (2) and the disc (10) are welded together, wherein the disc (10) comprises: a hub mounting section (10a); a plurality of spokes (10b) extending radially from the hub mounting section (10a) to an outer circumference of the disc (10), each spoke (10b) having a first reinforcing part (11a) and a second reinforcing part (11b) formed along both broad ends of the spoke (10b); and an annular disc flange (10c) extending in the axial direction of the vehicle wheel and connected on its axial outer side to the spokes (10b) by a surface curvature connecting section (R) formed by bending the spokes (10b) at their outer circumferential end in the wheel axis direction. where decorative holes (20) are defined by the adjacent spokes (10b), the hub mounting section (10a) and the disc flange (10c), and distal ends of the spokes (10b) point to a seating area between an inner circumferential surface of the rim (2) and an outer circumferential surface of the disc flange (10c) and the disc flange (10c) is welded to the rim (2), characterized by the fact that the disc flange (10c) is welded (5) to the rim (2) on its axial outer side only on its parts pointing towards the spokes (10b).

Description

[0001] The present invention relates to a wheel for a vehicle according to the preamble of patent claim 1.

[0002] Cheap and affordable steel wheels have been widely used. However, these steel wheels have a problem with their poor design compared to aluminum wheels. Therefore, in recent years, steel wheels with thin spokes and large decorative holes have been developed to achieve an appearance similar to aluminum wheels.

[0003] According to EP 1 262 333 A2, a single piece of sheet metal is formed into a disc, and the disc includes a plurality of spoke units and an annular disc rim connecting the outer ends of the spoke units. Each of the spoke units also includes two spoke webs (reinforcing ribs), and the disc rim is arranged on an inner periphery of a rim well (recessed portion) to be connected thereto.

[0004] In DE 201 08 995 U1, on which the preamble of claims 1 and 2 is based, the disc is welded to the rim part with a number of weld seams adapted to the number of spoke arrangements.

[0005] US 2006 / 0071539 A1 shows a wheel with a two-piece wheel disc, and welding sections are provided only in the peripheral part of the decoration holes.

[0006] US 2006 / 0197371 A1 and US 2007 / 0222279 A1 show welds on the disc flange only in the area of ​​the outer distal ends of the wheel spokes.

[0007] In the case of discs containing these integrally formed thin spokes and large decorative holes, the ring portion (the disc flange or disc rim) at its decorative hole portion has the smallest width and thus the lowest strength. This can cause the decorative hole portion to be deformed by the disc forming and machining, and thus cause one end edge of the ring portion to become wavy. Therefore, welding the ring portion at its decorative hole portion results in poor welding and insufficient joint strength.

[0008] The object of the present invention is to provide a wheel for a vehicle comprising a rim and a disc having integrally formed spokes and large decorative holes and being welded to the rim, which can be manufactured with higher productivity and enables improved stress transfer from the rim to the wheel disc.

[0009] To achieve the above object, the present invention provides a wheel for a vehicle according to claim 1.

[0010] Since the rotating disc is deformed into an elliptical shape during travel, stress acts in the radial direction of the disc, causing the seating area between the disc and the rim to expand. Since the outer part of the seating area is welded according to the invention, stress is hardly exerted directly on the welded part of the outer part of the seating area. Therefore, less stress acts on the welded part compared to the case of welding to an inner part of the seating area.

[0011] In a wheel according to claim 1, since the surface curvature connecting portion located at an extension portion of the spoke has a larger material width and thus higher strength, an end edge of this portion is less likely to become wavy due to bending. Thus, by welding the seating surface facing the distal end of the spoke corresponding to this position, poor welding is reduced while ensuring reliable welding. Furthermore, a force from the rim to the hub is transmitted mainly through the spokes. If a part of the disc flange adjacent to the decorative holes has a narrow material width, the force is hardly transmitted through that part of the disc flange. Therefore, it is inefficient to weld that part of the disc flange because substantially no improvement in wheel stability will result.Thus, welding the seat surface facing the distal end of the spoke improves welding efficiency and productivity.

[0012] Typically, the force is transmitted from the rim to the hub via the rim, the welded part, the disc flange, the spokes, and the hub attachment portion in the order described. Therefore, if the spokes are too rigid, welding the disc flange, except for a portion facing the distal end of the spoke, allows a less rigid part of the disc flange to be welded than the distal end of the spoke. This alleviates stress concentration and improves the fatigue resistance of the welded part and the surrounding area.

[0013] Preferably, the outer peripheral surface of the disc flange is inserted into the inner peripheral surface of the recessed portion of the rim.

[0014] In this design, the outer shape of the disc is smaller and lighter in weight compared to the case where the outer peripheral surface of the disc flange is inserted into the inner peripheral surface of a rim bead seat. It is also easy to prevent the disc flange from interfering with a valve hole.

[0015] Preferably, the disc flange is also welded to the rim on its axial inner side.

[0016] Preferably, the axially inner end edge of the spokes is offset from an axial central part of the recessed section to the axial outer side.

[0017] In this design, the disc flange is recessed toward the inside relative to the rim, in the direction of the wheel axis. The outer end edge of the disc flange is barely visible from the outside. This makes the spokes appear as if they are directly connected to the rim, improving the wheel's design characteristics.

[0018] Preferably, the disc flange is also welded to the rim on its axial inner side.

[0019] Embodiments of the present invention are described below with reference to the figures.

[0020] Here we show: Fig. 1 is a front view showing an example of a steel wheel for a vehicle according to a first embodiment of the present invention; Fig. 2 is a sectional view along the line II-II in Fig. 1; Fig. 3 is a perspective view of a disc; Fig. 4 is an enlarged partial view of Fig. 2; Fig. 5 is a front view showing an example of a steel wheel for a vehicle according to a second embodiment not according to the invention; Fig. 6 is a sectional view along the line VI-VI in Fig. 5; Fig. 7 is an enlarged view of Fig. 6; Fig. 8 is a perspective view of a seating area between a rim and the disc; Fig. 9 is a sectional view showing an example in which the disk is fitted into a portion of the rim other than a recessed portion.

[0021] In the following description, a steel wheel is used as an example. However, the present invention covers not only the steel wheel, but also wheels made of other materials (e.g., titanium and titanium alloy), as long as a disk is formed from a circular plate blank by bending an outer periphery of the blank through a drawing process or the like to form a disk flange.

[0022] In contrast, aluminum, magnesium, and other materials have lower material strength than steel. Therefore, for such aluminum, magnesium, or other materials, a casting process is generally used to integrally form a thick disc. For this approach, the structure for welding the disc and the rim together is not a problem. Therefore, the present invention does not cover the above thick disc integrally formed by casting (forging).

[0023] Preferably, the wheel of the present invention meets the official standard for fatigue strength. However, the present invention can also be applied to wheels that do not need to meet the official standard for fatigue strength, such as wheels for industrial (agricultural) vehicles and spare wheels for emergency use (including temporary vehicle wheels).

[0024] It should be noted that the official standard for fatigue strength refers to Japanese Industry Standards (JIS) D 4103 “Automobile parts - Disc wheel - Performance requirements and marking”, however, if JIS D 4103 should be modified in the future, the official standard for fatigue strength refers to the modified official wheel fatigue strength applicable during the modification of JIS (and / or the International Standards Organization (ISO)).

[0025] Fig. 1 is a front view showing a wheel for a vehicle according to a first embodiment of the present invention. The (steel) wheel for a vehicle according to the embodiment of the present invention includes a steel rim 2 and a steel disc 10, wherein the disc 10 is inserted into the rim 2 at its recessed portion 2c to weld the disc 10 to the rim 2.

[0026] It should be noted that in the following description, a term "outer side" and a term "inner side" respectively refer to an outer part and an inner part of the wheel mounted on the vehicle, when viewed in the wheel axial direction. In a double tire structure of a truck in which two axially connected wheels are used, the term "outer side" and the term "inner side" refer to an inner one of the respective wheels, as described above. In contrast, the term "outer side" and the term "inner side" for the other outer wheel respectively refer to an inner part and an outer part of the wheel. This is because in the double tire structure, the outer wheel is turned inside out for connection with the inner wheel. For example, in the case of the inner wheel, an upper part of the Fig. 2 is oriented outwards, while in the case of the outer wheel a lower part of the Fig. 2 shown disc is oriented outwards.

[0027] The radial direction of the rim and disc is referred to as “inward” or “outward”.

[0028] In Fig. 1, the rim 2 has a substantially cylindrical shape and is designed to receive a tire between an outer flange and an inner flange formed at both ends of the rim 2.

[0029] The disc 10 is integrally formed from a steel plate. The disc 10 has a central hub hole 10d and a plurality of bolt holes 10e arranged circumferentially outward of the hub hole 10d and concentric with the hub hole 10d. The bolt holes 10e are used for attaching the hub. A substantially disc-shaped portion of the disc 10, where the hub hole 10d and the bolt holes 10e are formed, is hereinafter referred to as the hub attachment portion 10a.

[0030] Five long spokes 10b extend radially from the hub attachment portion 10a to the outer peripheral edge of the disc. Each of the spokes 10b has two reinforcement portions 11, 11 formed along both widthwise ends of the spoke 10b and extending in the longitudinal direction (circumferentially outward direction). The reinforcement portions 11, 11 each include a first reinforcement part 11a and a second reinforcement part 11b (see Fig. 3). The second reinforcement member 11b projects from the center of the spoke 10b to the outside of the wheel for connection to the first reinforcement member 11a. The first reinforcement member 11a extends substantially parallel to the hub attachment portion 10a to form an end edge of the spoke 10b.

[0031] The spoke 10b is bent at its outer peripheral end toward the inner side of the wheel to form a surface curvature connecting portion R. The spoke 10b is connected to an annular disc flange 10c through the surface curvature connecting portion R. The disc flange 10c extends in the wheel axis direction. The disc flange 10c extends in the wheel axis direction and forms a seating surface for insertion into the rim 2 in the axial direction. The disc flange 10c serves to connect the individual spokes 10b to each other to ensure sufficient strength.

[0032] Five substantially triangular decorative holes 20 are formed, each of which is defined by the two adjacent spokes 10b, 10b, a part of an outer peripheral end of the hub attachment portion 10a, and a part of an outer end of the disc flange 10c. The decorative holes 20 are generally designed to reduce weight and allow heat to pass through.

[0033] A distal end 12 of the spoke is defined as the area between the contact points where two extension lines L, L of the widthwise ends of the spoke 10b contact the rim 2 (in this embodiment, the recessed portion 2c). A part facing a distal end 12 in a seating area between an inner peripheral surface of the rim 2 (the recessed portion 2c), as described later, and an outer peripheral surface of the disc flange 10c is welded to form a weldment 5.

[0034] The rim 2 has a valve hole 15 on its side wall (which is arranged circumferentially outwardly of the recessed portion). However, the valve hole 15 does not interfere with the disc 10, since the disc and the rim are welded together at the recessed portion of the rim, as shown in Fig. 2. Therefore, it is not necessary to provide the disc 10 with a notch.

[0035] Fig. 2 is a sectional view along the line II-II in Fig. 1. In Fig. 2, an outboard bead seat is formed within the outboard flange of the rim 2, in which a tire bead is seated. A small-diameter recess portion 2c is formed within the outboard bead seat. The outboard bead seat and a recess portion 2c (an outboard part thereof) are continuously connected to each other by a sidewall 2a. Specifically, the recess portion 2c and the sidewall 2a are connected to each other by a bent portion 2b. An inboard bead seat is formed within the recess portion 2c by a sidewall. The inboard bead seat is connected to an inboard flange. In the following description, the term "recess portion" refers to an outboard part of the recess portion (a connecting part to the outboard bead seat).

[0036] The rim 2 can be manufactured, for example, by rolling a steel plate into a cylindrical shape and then subjecting the cylindrical steel plate cylinder to roll forming or the like into a predetermined cross-sectional shape. However, the present invention is not limited to these manufacturing methods.

[0037] The hub attachment portion 10a of the disc 10 lies substantially on a flat plane. In contrast, the spoke 10b extends from the hub attachment portion 10a, is bent toward the outside of the wheel, extends outward in the wheel radial direction and substantially parallel to the hub attachment portion 10a, is connected to the inside of the wheel at the surface curvature connection portion R, and is then connected to the disc flange 10c. The widthwise central portion 13 of the spoke is enclosed by the reinforcement portions 11 of the spoke 10b and is positioned further toward the inside of the wheel relative to the reinforcement portions 11.

[0038] The disc 10 can be made, for example, from a square steel plate. Manufacturing the disc 10 may include: punching the square steel plate into a shape with four rounded corners; forming decorative holes on the punched steel plate; and subjecting the punched steel plate to a drawing (pressing) process to bend the plate and thereby form a disc flange. The disc flange 10c may be corrugated by machining its end edge, as described later.

[0039] Fig. 3 is a perspective view of the disc 10. In Fig. 3, a raised portion 14 and a connecting portion 15 are formed on an outer periphery of the hub attachment portion 10a of the disc. The raised portion 14 adjoins the second reinforcement part 11b of the spoke 10b, and the connecting portion 15 is connected to the raised portion 14. These elements are formed together into a rib that encloses the two sides and the apex of the decorative hole 20. The connecting portion 15 extends substantially parallel to the hub attachment portion 10a and is connected between the first reinforcement parts 11a of adjacent spokes.

[0040] The surface curvature connecting portion R extends from its proximal end toward the outer periphery and is connected to the disc flange 10c. Thus, the decoration hole 20 approximately forms a pentagon when viewed obliquely.

[0041] A portion adjacent to the decorative holes 20 in the disc flange 10c has the smallest material width and thus the lowest strength. Therefore, when the disc flange 10c is formed by bending, this portion of the disc flange 10c may be deformed downward (in the bending direction), causing the end edge of this portion of the disc flange 10c to become wavy. Therefore, welding the ring portion to the decorative hole portion may result in poor welding and insufficient joint strength.

[0042] In contrast, a portion adjacent to the surface curvature connecting portion R located at the extension portion of the spoke 10b has a larger material width and thus higher strength. Therefore, the end edge of this portion of the disc flange 10c is less likely to become wavy due to bending. Thus, welding the seat surface near the distal end 12 of the spoke, which corresponds to this portion of the disc flange 10c, ensures reliable welding.

[0043] A force is transmitted from the rim to the hub mainly through the spokes 10b. If the part of the disc flange 10c adjacent to the decorative holes 20 has a narrow material width, the force is hardly transmitted through this part of the disc flange 10c. It is inefficient to weld this part of the disc flange 10c because it will result in essentially no improvement in wheel strength.

[0044] In this regard, welding the seating surface facing the distal end 12 of the spoke reduces poor welding and improves welding efficiency and productivity.

[0045] The present invention is not limited to any particular welding method, but may utilize many welding methods, including, for example, laser welding, plasma welding, CO2 arc welding, metal active gas (MAG) welding, submerged arc welding, and tungsten inert gas (TIG) welding. However, in the case where the welded part is visible on the outer surface of the wheel, laser welding, plasma welding, or TIG welding may be preferably used to give a welded bead surface a more aesthetic appearance. In particular, hot wire TIG welding or submerged arc welding may be preferred in terms of cost, reliable weld strength, and appearance.

[0046] The disc flange 10c may extend in the wheel axis direction parallel to the recessed portion 2c of the rim. Alternatively, the disc flange 10c may extend such that its diameter is slightly enlarged at the distal end so that the disc flange 10c fits tightly against the rim 2.

[0047] The fitting and welding between the rim 2 and the disc 10 are described below with reference to Fig. 4, an enlarged partial view of Fig. 2. In Fig. 4, the outer peripheral surface of the disc flange 10c is inserted into the inner peripheral surface of the recessed portion 2c of the rim 2 to form the seating area. An outer part of the seating area is welded to form the weldment 5 to connect the rim 2 to the disc 10.

[0048] Welding the outer part of the seat area results in improved welding strength compared to welding the inner part (a weldment 5b in Fig. 4) of the seating area. The possible reasons for this are as follows. As the rotating disc is deformed into an elliptical shape during driving, a force acts in the radial direction of the disc (in the lateral direction in Fig. 4) a stress causing an expansion (lateral separation) of the seating clearance between the disc 10 and the rim 2. It is therefore conceivable that in the case of welding the inside part of the seating area, the stress causing an expansion of the seating clearance is transmitted from the outside part of the seating area to the welding part (the welding part 5b in Fig. 4) is transferred and the stress acting on the welded part increases due to the lever principle.

[0049] In contrast, when welding the outer part of the seat area, the stress causing the seat pitch to widen acts only directly on the welded part of the outer part of the seat area. Therefore, less stress acts on the welded part compared to the case of welding the inner part of the seat area.

[0050] In the case of welding the inboard portion of the seat area, the welded portion is preferably offset toward the outside of the wheel, making it less likely that the lever principle will act. That is, an inboard end edge 10c of the disc flange 10c is preferably positioned outward relative to an axial center portion CE of the recessed portion 2c. This allows for even further weight reduction.

[0051] It should be noted that the axial center CE of the recessed portion 2c is represented as the center of a distance between an outer end edge 2c (outer) and an inner end edge 2c (inner) of the recessed portion 2c. An outer end edge 2c (outer) and an inner end edge 2c (inner) of the recessed portion 2c form contact points or bending points where the straight inner peripheral surface of the recessed portion 2c, which extends parallel to the wheel axis direction, merges into the inner peripheral surfaces 16, 16 of the sidewall.

[0052] Since the axial length of the seating area between the disc flange 10c and the rim 2 is greatly reduced, the connection strength is reduced and uneven running is caused.

[0053] The inside end edge 10c (inside) of the disc flange 10c may have a wavy portion.

[0054] When the outer end edge 10c (outer) of the disc flange 10c, which is adjacent to the decorative holes 20, is arranged inward relative to the outer end edge 2c (outer) of the recessed portion 2c, the disc flange 10c is retracted toward the inside of the wheel relative to the rim 2. Therefore, the outer end edge 1c (outer) is difficult to see from the outside, as shown in Fig. 5. This makes the spokes appear as if they are directly connected to the rim, and the design characteristics of the wheel are improved.

[0055] There may be a case where a center portion exists between the surface curvature connecting portion R and the outer end edge 10c (outer) of the disc flange 10c parallel to the wheel axis direction, depending on the degree of bending of the outer peripheral end of the disc. In this case, the outer end edge 10c (outer) of the disc flange 10c is defined as the area adjacent to the decorative holes 20, whereas the seating area between the inner peripheral surface of the recessed portion and the outer peripheral surface of the disc flange 10c is defined as the area where the outer peripheral surface of the disc flange 10c, including the aforementioned center portion, is fitted into the inner peripheral surface of the recessed portion.

[0056] The outer end edge 10c (outer) of the disc flange 10c may have a wavy portion.

[0057] Fig. 5 is a front view showing a wheel for a vehicle according to a second embodiment. The (steel) wheel for a vehicle according to the second embodiment includes the steel rim 2 and the steel disc 10, wherein the disc 10 is inserted into the rim 2 at its recessed portion 2c to weld the disc 10 to the rim 2. Fig. 6 is a sectional view along the line VI-VI in Fig. 5.

[0058] The disc flange 10c is wider in the second version than in the first version. In the Fig. In the example shown in Figure 6, the inner end edge 10c (inner) of the disc flange 10c extends in the wheel axis direction beyond the axial center CE of the recessed portion 2c, to the vicinity of the inner end edge 2c (inner) of the recessed portion. However, ensuring a sufficient width of the disc flange 10c does not always involve extending the inner end edge 10c (inner) of the disc flange 10c beyond the central part 10e of the recessed portion, as in this case, for example, when the recessed portion 2c itself is sufficiently long.

[0059] A part adjacent to the decorative hole in the seating area between the inner peripheral surface of the recessed portion 2c and the outer peripheral surface of the disc flange 10c is welded to form a weldment 6. It should be noted that the part (of the seating area) adjacent to the decorative holes is referred to as the seating area, except for at least a part facing the distal end of the spoke. The decorative holes each have a corner R2 that is curved for manufacturing purposes. The width of the disc flange 10c at the corner R2 is wider than the width of the disc flange 10c in the center portion of the decorative hole. Therefore, it is preferable to weld the seating area not only outside the part facing the distal end of the spoke, but also outside a part facing the corner R2 of the decorative hole, from the viewpoint of welding a less rigid part of the disc flange, as discussed later.

[0060] An end point of the corner R2 of the decorative hole is designated as the point where the curvature of the corner ends. A portion of the seating area extending along the decorative hole from the end point of the corner R2 across the center portion of the decorative hole to an end point of another corner R2 is welded.

[0061] A force is normally transmitted from the rim 2 to the hub (not shown) via the rim, the weldment 6, the disc flange 10c, the spokes 10b, and the hub attachment portion 10a, in the order mentioned. Therefore, when the distal end 12 of the spoke is welded, stress concentration may occur at the welded portion due to the overlying rigid spoke. Thus, by welding the seat portion except the distal end 12, the less rigid part of the disc flange 10c is welded than the spoke 10b. This reduces the stress concentration at the welded portion and thus improves the fatigue resistance of the welded portion and its adjacent area.

[0062] Now the seating and welding shape between the rim 2 and the disc 10 is measured in relation to Fig. 7, an enlarged partial view of Fig. 6. In Fig. 7, the outer peripheral surface of the disc flange 10c is inserted into the inner peripheral surface of the recessed portion 2c of the rim 2 to form the seating portion. An outer side part of the seating portion is welded to form the weldment 6, and the rim 2 and the disc are joined together.

[0063] The welding of the outer part 6 of the seat area results in an improved welding strength, compared to the welding of the inner part (a welded part 6b in Fig. 7) of the seating area. The reason for this is the same as in the first embodiment of the present invention.

[0064] In the first design, a portion of the seating area is not welded, except for the portion facing the distal end of the spoke. In the second design, a portion of the seating area facing the distal end of the spoke is not welded.

[0065] In the present invention, the inside part of the seat portion may preferably be welded in addition to the outside part of the seat portion in view of improving the strength and stability.

[0066] As in Fig. 2 and Fig. 6, the disc flange 10c is inserted into the recessed portion 2c of the rim 2. However, as shown in Fig. 9, the disc flange 10c may also be inserted into a portion of the rim 2 other than the recessed portion, such as a bead seat 2f. Inserting the disc flange 10c into the bead seat 2f ensures a larger aesthetic surface of the wheel, compared to inserting the disc flange 10c into the recessed portion 2c, and provides a larger interior space of the wheel for accommodating a brake and other components.

[0067] The widthwise central portion 13 in the wheel axis direction relative to the reinforcement portions 11 may be arranged outside. Furthermore, an additional hole may be formed on the spokes for weight reduction. List of reference symbols 2 rims 2a side wall 2b Bending section 2c Advanced section 5, 6 Welded part 10 slices 10a Hub mounting section 10b spoke 10c disc flange 11 Reinforcement section 12 spoke ends 16 inner peripheral surface 20 decoration hole R connecting section R2 Decorative hole corner

Claims

[1] Wheel for a vehicle, the wheel comprising a rim (2) with a recessed portion (2c) and a disc (10) formed integrally from sheet material, the rim (2) and the disc (10) being welded together, wherein the disc (10) comprises: a hub attachment portion (10a); a plurality of spokes (10b) extending radially from the hub attachment portion (10a) to an outer periphery of the disc (10), each of the spokes (10b) having a first reinforcement member (11a) and a second reinforcement member (11b) formed along both widthwise ends of the spoke (10b); and an annular disc flange (10c) extending in the axial direction of the vehicle wheel and connected at its axial outer side to the spokes (10b) by a surface curvature connecting portion (R) formed by bending the spokes (10b) at their outer peripheral ends in the wheel axial direction, wherein decorative holes (20) are defined by the adjacent spokes (10b), the hub mounting portion (10a) and the disc flange (10c), and distal ends of the spokes (10b) point to a seating area between an inner peripheral surface of the rim (2) and an outer peripheral surface of the disc flange (10c) and the disc flange (10c) is welded to the rim (2), characterized by , that the disc flange (10c) is welded (5) to the rim (2) on its axial outer side only on its parts facing the spokes (10b). [2] The wheel for a vehicle according to claim 1, wherein the outer peripheral surface of the disc flange (10c) is fitted into the inner peripheral surface of the recessed portion (2c) of the rim (2). [3] The wheel for a vehicle according to claim 1, wherein the disc flange (10c) is also welded (5b, 6b) on its axial inner side to the rim (2). [4] The wheel for a vehicle according to claim 3, wherein the axially inner end edge (10c (inner)) of the disc flange (10c) is offset from an axial center (CE) of the recess portion (2c) to the axial outside.

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