JPH09123702A - Automotive disk wheel made of aluminum alloy metal plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the weight of an automotive wheel and to simultaneously improve the angular bending moment of the wheel by manufacturing a rim and a disk using aluminum alloy metal plates. SOLUTION: A disk is constructed in such a manner that an aluminum alloy disk formed by molding a metal plate having a hub attaching surface is welded to or firmly joined with the inner peripheral surface of an aluminum alloy rim formed by molding a metal plate. In this case, the hub attaching surface of the disk is provided with an inclined angle in a diameter direction from an outer peripheral part to a hub hole peripheral edge part and when a wheel is set (before fastened by a bolt) in the automotive hub, the wheel is brought into contact with an axle hub surface in the outer peripheral part of the hub attaching surface and is provided with a gap with the axle hub surface in the hub hole peripheral edge part of the attaching surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile disc wheel using an aluminum alloy plate material.

[0002]

2. Description of the Related Art Saving fuel consumption by reducing the vehicle weight of an automobile is important not only for reducing the fuel cost of the automobile, but also for maintaining and improving the global environment such as reducing the consumption of fossil fuel. The use of aluminum in automobile disc wheels (hereinafter simply referred to as "wheels") has been studied as a major contributor to weight reduction of automobiles. In particular, weight reduction of wheels greatly reduces the unsprung load of automobiles, and It has been clarified that it is also effective for improvement. Aluminum alloy wheels are already widely used in cast wheels. However, even though the specific gravity of aluminum alloy is about 35% of that of steel, the weight of aluminum alloy cast wheels is 15 to 20% less than that of steel wheels. This is because aluminum alloy castings are inferior in toughness and ductility to wrought materials, so aluminum alloy casting wheels must be thick. Therefore, at present, it cannot be said that the use of aluminum for automobile wheels sufficiently satisfies the demand for weight reduction. The aluminum alloy cast wheels, which are widely used nowadays, have become more important in terms of fashionability rather than being substantially lighter in weight, depending on the tastes of automobile users.

Various studies have been conducted to reduce the weight of an aluminum alloy plate material having excellent toughness and ductility for an automobile wheel. From the viewpoint of strength, corrosion resistance, etc., an Al-Mg alloy or Al-Mg-Si is used. A system alloy is selected. For the rims that make up the wheel, those using such aluminum alloy plate materials have already been put into practical use, but many discs still use thick castings, and the plate materials were also used for the discs. The adoption of wheels is limited to a part of racing cars.

[0004]

As shown in FIG. 1, a wheel using an aluminum alloy plate material has an aluminum alloy disk 30 inside a rim 20 made of an aluminum alloy plate on which a tire can be mounted on the outer peripheral surface by molding. Are joined by welding or binding. The aluminum alloy disc 30 is formed by press-forming a plate material, forging or cutting a casting, and a normal hat portion 5 is formed on the outer peripheral side of the hub mounting surface 3 to form the hub mounting surface. Reference numeral 3 has a through hole 2 for a hub mounting bolt (hub bolt) and a hub hole 1.

The production of automobile wheels is lighter, stronger,
From the viewpoint of productivity, as in the case of manufacturing a steel disc, an aluminum alloy plate disc obtained by press-forming a blank of a plate material having a uniform plate thickness is generally preferable. However, when a wheel composed of the aluminum alloy plate material disc 30 and the aluminum alloy plate material rim 20 thus obtained is subjected to a rotational bending moment durability test based on the test method specified in JIS D4103, the hub mounting surface is The tensile load stress is generated in the vicinity of the bolt through hole 2 of FIG. 3 and a part of the hub mounting surface 3 outside the bolt through hole 2, and a crack due to fatigue is generated around the bolt through hole 2 and in the vicinity thereof. There is a problem that durability is not satisfied. In order to satisfy the conditions of this rotational bending moment durability test, it is necessary to increase the thickness of the hub mounting surface 3. However, it is impossible to increase only the plate thickness of the hub mounting surface 3 by pressing a plate material having the same thickness. Therefore, in order to increase the rotational bending moment durability life, it is sufficient to provide the hub mounting surface 3 with a plate thickness corresponding to the required life to improve the fatigue strength, but it is also necessary for the portion not requiring the strength. The above plate thickness is given. As a result, the weight of the entire disk is increased, and the weight reduction, which is a feature of aluminum alloy wheels, cannot be sufficiently achieved.

[0006] A thick material is used for molding, and the thickness of the portion that is allowable in terms of strength is cut and removed to reduce the weight (Japanese Patent Laid-Open No. 56-41036), or the disc is insufficiently brazed. Proposals have been made to attach reinforcing parts by joining or the like (actual open flat 6-23801). However, these methods require an extra material that reduces the yield or extra man-hours, and cannot achieve the sufficient weight reduction effect and the economical efficiency by using the aluminum alloy sheet material.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention have diligently studied the shape of the wheel and the mounting method thereof so as to suppress the increase in the thickness of the disk and prevent the above-mentioned cracks from occurring.
As a result of research, the present invention has been completed. That is, the present invention is a wheel in which an aluminum alloy disc formed by a plate material having a hub mounting surface is joined to the inner peripheral side of an aluminum alloy rim formed by a plate material by welding or tightening. The hub mounting surface of the disc has an inclination angle in the radial direction from the outer peripheral portion toward the peripheral edge portion of the hub hole, and when the wheel is set on the automobile hub (before bolt tightening), the hub mounting surface is The aluminum alloy plate material, which is in contact with the axle hub surface at the outer peripheral portion thereof and has a gap between the axle hub surface at the peripheral edge portion of the hub hole of the mounting surface. It is a wheel for automobile manufacturing. The present invention will be described with reference to FIG. In the present invention, a wheel is formed by welding or tightly bonding an aluminum alloy disc 30 formed of a plate material having a hub mounting surface 3 to the inner peripheral side of an aluminum alloy rim 20 formed of a plate material. It is said to be 40. At that time, the disk 3
The hub mounting surface 3 of 0 has an inclination angle in the radial direction from the outer peripheral portion 6 toward the peripheral portion 7, and as shown in FIG.
When set on the automobile hub 8 (before tightening the bolts), the outer peripheral portion 6 of the hub mounting surface 3 is in contact with the axle hub surface 9, but the hub hole peripheral portion 7 of the mounting surface 3 is the axle hub hub. It is designed to have a gap with the surface.

A conventional wheel 40 made of an aluminum alloy plate is mounted on the hub 8 of the vehicle.
Disk 30 in the rotating bending moment durability test of
The stress generation condition of each part was examined. As a result, the disk 30
When a bending moment is applied to the hub mounting surface 3, a stress that tends to separate from the hub surface 9 is generated in a part of the hub mounting surface 3, and a stress is applied to the other part in a direction in which the mounting surface is pressed against the hub surface 9. Such stress acting parts alternately act on each part of the disk mounting surface by rotation. As described above, it was found that the fact that the tightening stress acting between the disc mounting surface 3 and the axle hub surface 9 changes due to the rotation deteriorates the rotational bending fatigue characteristics.

A rotating bending moment is generated in the wheel 40 by the driving force of the automobile and the vehicle load, and the stress generated by this moment is transmitted to the automobile hub 8 via the disk 30. The conventional automobile wheel may be made of steel or aluminum alloy, and the wheel 40 may be machined so that the axle hub surface 9 of the automobile side and the hub attachment surface 3 of the disc of the wheel side are parallel to each other. And is attached to the automobile hub 8. When the hub mounting surface 3 of the disc and the automobile hub surface 9 are parallel to each other as described above, when a rotational bending moment is applied in a state of being attached to the automobile, the stress generated by the rotational bending moment is directly transmitted to the disc and tightened. Due to the restraint by the bolts and nuts, alternating stress is generated at the periphery of the bolt holes as it rotates. This acting stress causes a concentrated load in the bolt through hole 2 or in the vicinity thereof to shorten the life of the wheel. In order to reduce such concentrated load, it is desired to reduce the stress applied to each part of the disk including the disk mounting surface 3 and to design the stress distribution more uniformly.

[0010]

3 is a partial sectional view showing a method of mounting the aluminum alloy wheel 40 shown in FIG. 2 on the automobile hub 8 according to the present invention. FIG. 3A shows a state before the wheel is fastened to the automobile hub 8. In the wheel of the present invention, the hub mounting surface angle Θ is provided on the hub mounting surface 3 of the disk 30 from the hub mounting surface outer peripheral portion 6 toward the hub hole peripheral edge portion 7. It is desirable to be in the range below the degree. More preferably 0.5 degrees or more,
4 degrees or less. Therefore, in the state before the hub mounting surface 3 is set on the hub 8 and the bolts are tightened, the axle hub surface 9 and the outer peripheral portion 6 of the hub mounting surface 3 are in contact with the hub surface 9, but the diameter toward the peripheral edge portion 7 of the hub hole. The gap between the hub mounting surface 3 of the disk and the hub surface 9 of the vehicle gradually increases in the direction. That is, before the wheel of the present invention is fastened to the hub with the hub bolt 10 and the fastening nut 11, there is a frustoconical gap between the hub mounting surface 3 of the disk and the hub surface 9 of the automobile.

The wheel of the present invention is attached to the automobile hub 8 as shown in FIG. 3 (B). That is, the wheel in the state of FIG. 3A is tightened by the hub bolt 10 and the tightening nut 11 until the entire surface of the hub mounting surface 3 contacts the hub surface 9. By tightening until the gap between the hub mounting surface 3 of the disc before tightening and the axle hub surface 9 comes into close contact, elastic stress is generated on the hub mounting surface 3. The stress applied to the disk due to the rotational bending moment during running or during the rotational bending moment durability test is partially offset by the elastic stress generated by mounting the disk of the present invention, and the stress generated in the disk is reduced. At the same time, the load stress distribution can be made uniform. As a result, the concentrated stress in the bolt through hole 2 and its vicinity is also reduced, and the durability against rotational bending moment of the wheel is significantly improved. The hub mounting surface angle Θ between the hub surface 9 of the automobile and the hub mounting surface 3 of the disc before tightening is preferably 0.5 or more and 6 degrees or less, but when the hub mounting surface angle Θ is less than 0.5 degrees. This effect is not sufficiently obtained, and if the hub mounting surface angle Θ becomes excessive, plastic deformation occurs in a part of the hub mounting surface 3 of the disk when tightened, and the elastic stress to be generated is relaxed, which is not preferable. . Therefore, the maximum value of the hub attachment surface angle Θ may be selected so that plastic deformation does not occur in the maximum stress generating portion generated by tightening, but it is preferably 6 degrees or less, more preferably 4 degrees or less.

[0012]

Embodiments of the present invention will be described below with reference to FIGS. Wheel size 5.5JJ shown in FIG.
X13 automotive disc wheel (dimensions: diameter 32
Rim 20 and disk 3 of 9.4 mm, width 140 mm)
0 was made by using an aluminum alloy plate JIS 5454 alloy rolled plate. The rim 20 was prepared by using a rotating rim forming roll after flash butt welding a rolled plate having a plate thickness of 4.4 mm into an annular shape by a usual method. The rim may be formed by roll forming, or by any method used for forming the rim of the plate material such as spinning forming or press forming. Also, a rim for a three-piece wheel may be used.

The disk was produced by press molding using a rolled plate having a plate thickness of 6.3 mm. The hub mounting surface angle Θ of the disk 30 is changed by changing the shape of the mounting surface part forming die of the press die so as to have an angle close to the predetermined hub mounting surface angle Θ, and in order to obtain a more accurate mounting angle, the hub mounting surface angle Θ The entire surface of No. 3 was turned and finished. The turning allowance at this time was 0.3 mm at maximum. The disk 30 manufactured in this manner was assembled with the rim 20 made of an aluminum alloy 5454 plate manufactured by a usual method by MIG welding around the entire circumference. The obtained aluminum alloy wheel 40 is set on the automobile hub 8,
Fig. 3 shows the state before tightening with the tightening nut 11.
(A). As shown in FIG. 3 (B), this is done until the hub mounting surface 3 of the disk is brought into close contact with the hub surface 9 of the automobile by the tightening nut 11 (until Θ = 0 by tightening).
After tightening, based on the automobile wheel test method specified in JIS D4103, the load condition is 233 kg-m.
As a result, a rotating bending moment durability test was performed. Table 1 shows the test results. The numbers in Table 1 show the number of revolutions (life) until the occurrence of cracks was confirmed by the rotating bending moment durability test. In addition, the weight of the aluminum alloy plate wheel manufactured in this example is 3.5 kg per piece, and the steel plate wheel of the same size is 6.5 kg. Therefore, according to the method of the present invention, the aluminum alloy plate wheel achieves a weight reduction of 45% as compared with the steel plate wheel.

[0014]

[Table 1]

In this embodiment, in order to accurately obtain a predetermined hub mounting surface angle Θ, the hub mounting surface 3 is finished by shaping after being formed into an approximate hub mounting surface angle. Hub mounting surface angle Θ
If sufficient accuracy can be obtained, it is more economical and desirable to perform molding of the entire disc and molding of the hub mounting surface angle at the same time. Also, molding of the mounting surface 3 can be performed separately by two-step molding. Is also good.

[0016]

As is apparent from the above embodiments, according to the present invention, a plate material having an even thickness is used to increase the wall thickness of the disk portion where fatigue cracks are likely to occur due to a rotating bending moment. Alternatively, the life of the wheel can be improved without reinforcement, which is a remarkable effect for reducing the unsprung weight of the automobile.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a conventional automobile wheel.

FIG. 2 is a sectional view of an automobile wheel showing an embodiment of the present invention.

FIG. 3 is a partial cross-sectional view of a wheel and an automobile hub showing a wheel mounting method of the present invention.

[Brief description of reference numerals]

 1 Hub Hole 2 Bolt Through Hole 3 Hub Attachment Surface 5 Hat Part 6 Hub Attachment Surface Outer Edge 7 Hub Hole Peripheral Edge 8 Automotive Hub 9 Axle Hub Surface 10 Hub Bolt 11 Tightening Nut 20 Rim 30 Disc 40 Wheel Θ Hub Attachment Surface Angle

Claims (1)

[Claims] 1. A wheel in which an aluminum alloy disc formed by a plate material having a hub mounting surface is joined to the inner peripheral side of an aluminum alloy rim formed by a plate material by welding or tightening. The hub mounting surface of the disk is in a radial direction from the outer peripheral portion toward the peripheral edge of the hub hole,
It has an inclination angle, and when the wheel is set on an automobile hub (before tightening bolts), it contacts the axle hub surface at the outer peripheral portion of the hub mounting surface, and the hub hole peripheral portion of the mounting surface is in contact. A disk wheel for an automobile made of an aluminum alloy plate material, characterized in that it has a gap between it and an axle hub surface.