JPH10258394A - Disk wheel and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk wheel excellent in durable strength at the welded part in a low cost. SOLUTION: The disk wheel 1 is composed of a disk 2 and a wheel 4. The tip part 3a of a press-in part 3 formed to the disk 2 is positioned to a bead sheet part 5 side by the distance to 1/2 of the sheet thickness at the tip part 3a of the press-in part 3 of the disk 2 from boundary between the bead sheet part 5 and a hump part 6. A welded bead end part D is positioned to the inner peripheral surface 6a of the hump part. A welded bead contacting angle as the angle between the welded bead and the inner peripheral surface of the hump part of the rim is formed to 100-130 deg.. The curving surface having 0.2R-0.5R with a shot peening work is formed at the welded bead end part D.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk wheel having excellent weld strength and a method for manufacturing the same.

[0002]

2. Description of the Related Art In an automobile wheel, a disc is press-fitted onto the inner peripheral surface of a bead seat portion of a rim, and the disc is welded.
In a two-piece wheel joined to a body, a disk formed with a plurality of spokes excellent in design is now partially adopted from an all-circumference weld type disk. Since the disk on which such spokes are formed is welded to the rim at the spokes, the overall welding length is shortened, and it is an important requirement to improve the strength, especially the durability of the welded portion.

For this reason, a structure as shown in FIG. 8 has been proposed in Japanese Utility Model Laid-Open No. 6-55802 with the aim of improving the durability of a weld. This conventional structure, as shown in FIG.
01, a flange 102 is formed on the periphery thereof, and a flange-shaped disk press-fit portion 103 is formed at the tip of the spoke portion 101 by bending. The disk press-fitting portion 103 is press-fitted to the inner peripheral surface, and the tip of the disk press-fitting portion 103 is made substantially coincident with the boundary between the bead seat portion 105 and the hump portion 106.
, The durability of the welded portion is improved.

[0004]

SUMMARY OF THE INVENTION The aforementioned Japanese Utility Model Laid-Open No. 6-55.
According to the conventional technique described in Japanese Patent Application Publication No. 802, although the effect of improving the welded part durability is obtained to some extent, the strength is slightly improved and remains insufficient. The reason is that the rim bead seat portion 105 is a portion that receives the load of the wheel, and providing a joint portion by welding at that portion directly receives the high stress, and has a problem in durability.

[0005] The rim hump portion 106 is usually an R shape having a small diameter, and since this portion is formed by roll forming (plastic working) in rim production, a reduction in the thickness of this portion cannot be avoided. The formation of a welded joint in a thin part of the steel reduces the durability.

In order to solve this problem, the present inventor has previously proposed a two-piece wheel in Japanese Patent Application No. 8-265678. This is a structure in which the tip of the press-fit portion of the spoke portion is welded with the tip of the press-fit portion located on the side surface or the bottom surface of the rim well. ,
It has sufficient durability for practical use.

However, in this structure, since a flange-shaped press-fit portion must be formed at the tip of the spoke portion in manufacturing the disk, the length of the spoke portion becomes longer and the size of the material must be increased. Occurs,
There was a problem of increased costs.

Accordingly, the present invention is to provide a new joining structure capable of improving the durability strength of a welded portion while eliminating the factor of cost increase.

[0009]

According to a first aspect of the present invention, a plurality of spokes are formed on an outer peripheral portion of a disk, and a plurality of spokes are provided at the ends of the spokes. In a disk wheel formed by forming a flange-shaped press-fit portion at the portion and press-fitting the press-fit portion to the inner peripheral surface of the bead seat portion of the rim and welding and assembling, the tip of the press-fit portion formed on the disc is referred to as a bead seat portion. The weld bead toe of gas arc welding that joins the two is located on the inner peripheral surface of the hump by positioning the distance from the boundary of the hump to a distance approximating 1/2 of the plate thickness at the tip of the press-fitting part of the disk. And the tangent angle of the weld bead, which is the angle between the weld bead and the inner peripheral surface of the hump portion of the rim, is 100 degrees or more and 130 degrees or more.
The disc wheel is characterized by having a curved surface of 0.2R to 0.5R formed by shot peening on the toe of the weld bead.

According to a second aspect of the present invention, a plurality of spokes are formed on an outer peripheral portion of a disk, and a flange-like press-fit portion is formed at a tip of the spoke portion, and the press-fit portion is formed as a rim. In the method for manufacturing a disc wheel, which is press-fitted into the inner peripheral surface of the bead seat portion and welded and assembled, the tip of the press-fit portion formed on the disc is formed at the tip of the press-fit portion of the disc from the boundary between the bead seat portion and the hump portion. Of 1
/ 2 on the side of the bead seat part,
A method of manufacturing a disk wheel, characterized in that a gas composition of gas arc welding for joining the two is a mixed gas mainly composed of Ar gas, and a shot peening process is performed on a toe portion of the obtained weld bead.

In the disk wheel of the present invention, the length of the spoke portion is deviated from the boundary between the bead seat portion and the hump portion toward the bead seat by an amount approximating 1/2 of the thickness of the press-fit portion at the tip of the disk. Since the position is set to the shifted position, the material size in the disk molding can be reduced.
As a result, the problem of the cost caused in the previously proposed Japanese Patent Application No. 8-265678 was solved.

Further, a weld bead is formed from the bead sheet portion to the hump portion, but the toe position of the weld bead is limited to the entrance portion of the inner circular arc portion of the hump portion by setting the length of the spoke to the above position. In addition, since the gas for gas arc welding is a mixed gas mainly composed of Ar instead of conventional CO ₂ , the thickness of the weld bead becomes thinner as it becomes closer to the toe.

As a result, the tangent angle of the weld bead, which is the angle between the weld bead and the inner periphery of the hump, can be set to 100 degrees or more and less than 130, so that stress concentration can be greatly reduced. Further, in the present invention, since a curved surface of 0.2R to 0.5R is formed at the toe end of the weld bead by shot peening, the effect of further reducing the concentration of stress at the start end of the weld bead can be exhibited. The synergistic effect can provide a disk wheel having excellent weld strength.

[0014]

Next, an embodiment of the present invention will be described with reference to the embodiments shown in FIGS.

FIG. 1 is a longitudinal sectional view showing a main part of a disk wheel according to the present invention, and FIG. 2 is a perspective view showing the disk. 1 and 2, reference numeral 1 denotes a disk wheel including a disk 2 and a rim 4. The disk 2 has a plurality of spokes 2a formed on an outer peripheral portion thereof at equal intervals in a circumferential direction and radially protruding. A flange-shaped press-fit portion 3 is formed at the tip of each spoke portion 2a in a straight line so that the diameter of the back surface of the disk is reduced at a taper angle α of 5 ° with respect to the axial direction of the wheel. Have been.

Further, the diameter of the outer peripheral surface of the press-fitting portion 3 is set to a diameter that can be press-fitted to the inner peripheral surface of the bead seat portion 5 of the rim 4 described later, and the outer peripheral surface has a circumferential shape.
The bead sheet portion 5 is formed on an arc surface along the inner peripheral surface.

The rim 4 is formed in an annular shape, and a concave well 4a is formed at an intermediate portion in the axial direction thereof, and a hump portion 6 is further formed continuously and integrally therewith. The bead sheet portion 5 is formed continuously from the portion 6. The bead seat portion 5 is formed in a linear shape whose outer diameter increases at a taper angle α of 5 ° with respect to the axial direction of the rim 4.

In FIG. 1, reference numeral 3a denotes a tip of the press-fitting portion 3, 6a denotes an inner peripheral surface of the hump portion 6, and 8 denotes a welding bead. FIG. 3 is an explanatory view showing the press-fitting position of the disc 2 and the rim 4 in FIG. 1. The press-fitting position of the tip 3 a of the press-fitting portion 3 is determined from the boundary 7 between the bead seat portion 5 and the hump portion 6. distance t ₂ which approximates the thickness t ₁ × _1/2 are then positioned on the bead seat 5 side.

The reason for this is that the tangent angle θ of the weld bead 8 is set to 100 degrees or more and 130 degrees or more as shown in FIG. 4 in combination with arc welding using a mixed gas mainly composed of Ar gas, which is another important requirement in the present invention. In order to make it less than degree.

That is, in FIG. 5, when the press-fit portion 3 of the spoke 2a is lengthened and its tip 3a 'is positioned at the broken line, the weld toe E is moved from the inner periphery of the hump 6 to the inside of the rim well 4a. relates to a deeply intruded position inside the R portion connected with the side surface, the tangent angle theta _E with its hump inner peripheral surface 6a is abruptly decreased as shown in FIG. 5, theta _E <1
It will be about 00 degrees.

On the other hand, the length of the press-fit portion 3 in the spoke 2a is reduced, and the tip 3a is moved to the above-mentioned position (FIG. 5).
5, the weld toe D is formed on the inner peripheral surface of the hump portion 6, more specifically, the inner peripheral portion of the rim bead seed portion 5 and the inner peripheral portion of the hump portion 6 as shown by the solid line in FIG. 5. (The entrance of the hump inner peripheral surface 6a), and the tangent angle θ _D to the hump inner peripheral surface 6a increases as shown in FIG.

The present inventors have found that the tangent angle can be increased by using a mixed gas of Ar—CO ₂ . Therefore, as in the above embodiment, the tangent angle θ is set by combining the tip of the press-fitting portion 3 at the portion 3a and using the above-mentioned mixed gas.
_D could be set to 100 degrees <θ _D <130 degrees.

The reason why the tangent angle is set to 100 to 130 degrees as described above is that if the tangent angle is less than 100 degrees, the effect of alleviating stress concentration is small, and the durability of the welded portion is reduced, which is disadvantageous.
This is because if the angle is set to 30 degrees or more, welding is not possible, and other means must be used in combination, which is not economical.

Further, according to the present invention, in addition to the formation of the weld bead as described above, the grain size φ0.4 mm to φ1.0 m from the shot direction of the arrow A in FIG.
m at the toe D, as shown in FIG. 6 (b).
A curved surface B of 2R to 0.5R is formed. This further reduces stress concentration.

If the shot grain size of the shot peening is less than φ0.4 mm, it is difficult to form a curved surface of 0.2R to 0.5R at the weld bead toe. Also,
If the diameter exceeds φ1.0 mm, the equipment cost is undesirably high. When the curved surface is less than 0.2R, the effect of reducing the stress concentration is insufficient. On the other hand, when the surface exceeds 0.5R, the effect does not increase much, and the equipment cost of the shot peening apparatus increases, which is uneconomical. It is.

In the present invention, the above-mentioned mixed gas mainly composed of Ar means a mixed gas of 80% or more of Ar with the balance being CO ₂ or the like, and the amount of the mixed gas used may be the same as in the case of conventional CO ₂ alone. .

[0027] Figure 7 shows the shape of the weld bead 9 by the conventional CO ₂ gas arc welding, the weld bead tangential angle theta ₁ theta
₁ <100 °, and the stress concentration at the weld toe C is inevitable, resulting in a disk wheel with low durability.

Next, the results of comparative measurement of the durability of the welded portion between the product of the present invention and the conventional product in which the gas used for welding was changed are shown. [Example product of the present invention] Wheel size 15 × 6J disc Plate thickness t: 4.5 mm, material: strength 440 N / mm Class ² 5-spoke (spoke width 120 mm) Rim plate thickness t: 3.5 mm, material: strength 440 N / end position of the mm ² grade disc press-in portion is shown in FIG. 3 t _1/2 = t 2
The position of the weld bead toe was set to the position D in FIG. The welding was performed by arc welding using a mixed gas of Ar 80% and CO ₂ 20%, and the tangent angle of the weld bead (θ in FIG. 4).
Is 110 degrees. The shot peening process for the bead toe is air pressure 5 kg / cm ² , nozzle diameter φ7
mm and a shot diameter of 0.8 mm, a 0.4R curved surface was formed.

[Comparative Example] Wheel size, disc,
End position of the specifications and disk press fit portion of the rim is as defined above Example Product, welding with arc welding of CO ₂ plain, weld bead tangent angle 94 degrees obtained, shot peening to the weld bead toe Manufactured without treatment.

[Measurement results] JISD
Table 1 shows the results of the measurement of the durability of the welded portion (N = 5 average value) according to the method of the 4103 automobile disk wheel radial load durability test.

[0031]

[Table 1]

[0032]

As described above in detail, according to the present invention, it is possible to provide an inexpensive disk wheel having excellent durability at the welded portion, and it has an industrially useful effect.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a disk wheel of the present invention.

FIG. 2 is a perspective view showing an example of the disk of the present invention.

FIG. 3 is a longitudinal sectional view showing a press-fitting position of a rim and a disc in FIG. 1;

FIG. 4 is a longitudinal sectional view showing a tangent angle of a weld bead.

FIG. 5 is a longitudinal sectional view of a main part showing a change in a position of a weld bead toe and a tangent angle of the weld bead.

FIG. 6 (a) is an enlarged vertical sectional view showing a shot direction of shot peening for a weld bead toe,
(B) is an enlarged longitudinal sectional view showing a curved surface by shot peening.

FIG. 7 is a longitudinal sectional view of a main part showing a conventional weld bead shape and a weld bead tangent angle.

FIG. 8 is a longitudinal sectional view showing a conventional structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Disc wheel 2 ... Disc 2a ... Spoke part 3 ... Flange-shaped press-fit part 3a ... Tip of press-fit part 5 ... Bead seat 6 ... Hump part 6a ... Hump inner peripheral surface 7 ... Boundary between bead seat and hump 8 ... Weld bead θ … Weld bead tangent angle D… weld bead toe θ _D … weld bead tangent angle

Claims (2)

[Claims] 1. A plurality of spokes are formed on an outer peripheral portion of a disk, and a flange-like press-fit portion is formed at a tip of the spoke portion, and the press-fit portion is press-fitted on an inner peripheral surface of a bead seat portion of a rim. In the disk wheel assembled and welded, the tip of the press-fit portion formed on the disc is bead seated by a distance approximating half the thickness of the tip of the press-fitted portion of the disc from the boundary between the bead seat and the hump. Side, the weld bead toe of gas arc welding for joining the two is located on the inner peripheral surface of the hump, and the tangent angle of the weld bead, which is the angle between the weld bead and the inner peripheral surface of the hump portion of the rim, is 100 degrees. At least less than 130 degrees, and the toe of the weld bead is shot-peened to 0.2R or more.
A disc wheel having a curved surface of 0.5R. 2. A plurality of spokes are formed on an outer peripheral portion of a disk, and a flange-like press-fit portion is formed at a tip of the spoke portion, and the press-fit portion is press-fitted into an inner peripheral surface of a bead seat portion of a rim. In the method of manufacturing a disk wheel to be fitted and welded and assembled, the tip of the press-fit portion formed on the disc is distanced from the boundary between the bead seat portion and the hump portion by a distance approximating 1/2 of the plate thickness at the tip of the press-fit portion of the disc. The gas composition of the gas arc welding that joins both is
A method for manufacturing a disk wheel, comprising: forming a mixed gas mainly composed of r gas; and performing shot peening on a toe portion of the obtained weld bead.