JPH08324202A - Large, medium light alloy wheel - Google Patents

Abstract

PURPOSE: To improve fatigue strength in spite of being manufactured by casting by connecting a hub installing part and a curved part to each other through an inclined wall part inclined inside in the wheel shaft direction to a radial directional extension line of the hub installing part. CONSTITUTION: A disk part 12 has an inclined wall part 21 between a hub installing part 14 and a curved part 15, and connects them to each other through it. The inclined wall part 21 is composed of a wall part inclined by an angle θnot less than 35 deg. inside in the wheel shaft direction to a radial directional extension line 22 of the hub installing part 14, and is composed of a short wall extending in a straight line shape, and is integrally connected to the hub installing part 14 on one end, and is integrally connected to the curved part 15 on the other end. Since a wheel 11 has the inclined wall part, a section modulus becomes large in a part of the inclined wall part 21, and as a result, the hub installing part 14 is reinforced by a highly rigid ring in an outer peripheral part, and flexural rigidity of the hub installing part 14 is improved, and since a very near part of a bolt hole 17 exists in the vicinity of the inclined wall part 21, it is reinforced in the circumferential direction by an effect of the inclined wall part 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to large and medium-sized light alloy wheels used for, for example, buses and trucks.

[0002]

2. Description of the Related Art In recent years, as shown in FIG. 7, a wheel for a bus or a truck is light in weight for improving fuel efficiency and has a disc portion 2 and a rim portion 3 for improving the design of the wheel.
However, an integrally molded light alloy wheel (for example, an aluminum alloy wheel) 1 is often used. The wheel 1 is used either as a single wheel or as a double wheel with the outer surfaces of the disk portions combined. This light alloy wheel is usually manufactured by casting or forging.

[0003]

The weakest part of the wheel is the bolt hole, and cracks form from the bolt hole when a repeated load is applied. Among the conventional light alloy wheels manufactured by casting, the plate thickness of the hub mounting portion of the disk portion is increased in order to secure the strength in the vicinity of the bolt holes. Therefore, the weight of the wheel is inevitably increased. In order to suppress the weight increase and improve the strength, it is effective to manufacture the light alloy wheel by forging. However, there is a problem that the shape of the wheel is limited because the shape of the wheel is limited in order to enable forging, wheels of various designs cannot be manufactured. An object of the present invention is to provide a large / medium size light alloy wheel having improved strength (fatigue strength) regardless of being manufactured by forging. Another object of the present invention is to achieve the above object,
It is an object of the present invention to provide a large, medium-sized light alloy wheel capable of stabilizing the load applied to the contact surface with the hub in the case of a single wheel or the contact surface between the wheels in the case of a double wheel.

[0004]

The large and medium size light alloy wheels of the present invention that achieve the above-mentioned objects of the present invention are as follows. (1) A casting type large or medium-sized light alloy wheel having a disc portion and a rim portion, the disc portion having a hub mounting portion and a curved portion extending between the hub mounting portion and the rim portion, A large, medium-sized light alloy wheel in which the hub mounting portion and the curved portion are connected via a sloping wall portion inclined by 35 ° or more inward in the wheel axial direction with respect to a radial extension line of the hub mounting portion. (2) A large groove according to (1), wherein an annular groove including a bolt hole is formed in the groove width centering on the wheel shaft center, on at least one surface of the wheel mounting portion in the wheel shaft inner and outer surfaces.
Medium size light alloy wheel.

[0005]

In the large and medium-sized light alloy wheel of the above (1), since the slanted wall portion is provided, the bending rigidity of the hub mounting portion and the circumferential rigidity in the vicinity of the bolt hole are remarkably increased, and repeated rotational bending and repeated radial load are applied. Durability is significantly improved and fatigue strength is improved. In the large and medium-sized light alloy wheels of (2) above, in addition to the effect of (1) above, an annular groove is provided on the surface of the hub mounting portion. During attachment, the surface of the part near the bolt hole does not hit, preventing fretting of the surface of the part near the bolt hole and stabilizing the application of load.

[0006]

1 to 4 show a first embodiment of the present invention, and FIGS. 5 and 6 show a second embodiment of the present invention. Constituent parts common to the first and second embodiments of the present invention are designated by the same reference numerals in both embodiments. First, the structure and operation common to the first and second embodiments of the present invention will be described with reference to, for example, FIGS. 1 to 4 or FIGS. As shown in FIG. 1, the large and medium-sized light alloy wheel 11 according to the embodiment of the present invention includes a disk portion 12 and an annular rim portion 13.
And an integral structure of a light alloy, for example, an aluminum alloy casting.

The disk portion 12 is curved between a hub mounting portion 14 mounted on a hub of an axle shaft of a vehicle (bus, truck or other large or medium-sized vehicle), and between the hub mounting portion 14 and the rim portion 13. And an extending curved portion 15. The hub mounting portion 14 extends in a direction orthogonal to the wheel axis, and has a hub hole 16 in the center and a bolt hole 17 around the hub hole 16. A plurality of bolt holes 17 are provided on the circumference around the wheel shaft center at equal intervals in the circumferential direction. The wheel 11 is fixed to the hub by inserting the hub bolt attached to the hub 18 into the bolt hole 17 and screwing the hub nut into the hub bolt (see also FIGS. 5 and 6). The bolt hole 17 has a cylindrical hole portion 17a and spherical seat portions 17b at both ends thereof, and the hub nut is pressed by the spherical seat portion 17b to apply a load to the spherical seat portion 17b.

As shown in FIG. 1, the disk portion 12 has a slant wall portion 21 between the hub mounting portion 14 and the curved portion 15, and the hub mounting portion 14 and the curved portion 15 are directly connected to each other. They are not connected, but are connected to each other via the slanted wall portion 21. The slanted wall portion 21 is formed of a wall portion that is inclined inward in the wheel axial direction (direction A) by an angle θ of 35 ° or more with respect to the radial extension line 22 of the hub mounting portion 14. The slanted wall portion 21 is a short wall extending linearly, and is integrally connected to the hub mounting portion 14 at one end and is integrally connected to the bending portion 15 at the other end. At the connection point 23 between the slant wall portion 21 and the hub mounting portion 14, the slant wall portion 2
1 is bent from the hub mounting portion 14, and the bending direction is outward in the radial direction of the wheel and inward in the axial direction of the wheel, that is, obliquely outward. At the connection point 24 between the slanted wall portion 21 and the inner circumferential side end portion of the curved portion 15, the curved portion 15 is bent from the slanted wall portion 21, and the bending direction is the inner circumferential side end portion of the curved portion 15. The tangent line is closer to the extension axis 25 of the swash wall portion 21 in the direction orthogonal to the wheel axis.

The slanted wall portion 21 is located on the outer peripheral side of the outer diameter of the hub 18, and does not interfere with the hub 18 even if the slanted wall portion 21 is inclined in the wheel axis direction. Further, the slanted wall portion 21 does not protrude outward in the wheel axial direction from the wheel axial direction outer surface of the hub mounting portion 14, and does not interfere with each other even when the wheels are used in a double (FIG. 6) type. Although a plurality of decorative windows 26 are provided in the curved portion 15 in the wheel circumferential direction, the decorative windows 26 are located outside the slanted wall portion 21 in the wheel radial direction. Wall 2
1 is continuous over the entire circumference in the wheel circumferential direction. The thickness of the hub mounting portion 14 of the disk portion 12 is equal to that of the slanted wall portion 2.
It is thinner than the thickness of the hub mounting portion of the conventional wheel, which does not have 1, and is reduced by, for example, about 10%.

Next, the operation of the common component will be described. Since the wheel 11 is manufactured by casting from a light alloy, the degree of freedom of the shape is large as compared with the case where it is manufactured by forging, and there is no restriction from the forging die. Since the wheel 11 has the slant wall portion 21, the section modulus becomes large in the slant wall portion 21, and as a result, the hub mounting portion 14 is reinforced by the ring having high rigidity at the outer peripheral portion, and the hub mounting portion 14 is mounted. Part 14
In addition to improving the bending rigidity, the immediate vicinity of the bolt hole 17 is in the vicinity of the swash wall portion 21, so that the effect of the swash wall portion 21 is reinforced in the circumferential direction, and the rigidity can be increased in the circumferential direction.

Conventionally, the wheel 11 is subjected to a rotary bending fatigue test (life test) shown in FIG. 3 and a radial load test (drum test) shown in FIG. 4 to confirm its fatigue strength. The cracked portion is the bolt hole 17. Since the bending rigidity of the hub mounting portion 14 is increased by the slanted wall portion 21, the number of repeated loads of the live test becomes large, and in terms of stress, the circumferential stress at the edge portion of the bolt hole 17 becomes small. Further, since the sloping wall portion 21 enhances the rigidity in the vicinity of the bolt hole 17, the bolt hole stress in the drum test becomes small.
FIG. 2 shows the results obtained by finite element method analysis of changes in the circumferential stress at the peripheral edge of the bolt hole portion 17 when the inclination angle θ of the slant wall portion 21 from the extension line of the hub attachment portion is variously changed. There is. Moment M is 709 kgfm in the life test
In the drum test, the radial load P is 2640 kgf.
Was calculated as As can be seen from FIG. 2, θ is about 35 °
In the smaller range, the stress reduction rate when the θ is increased is high, and when θ is about 35 ° or more, the stress reduction is no longer observed. Therefore, it can be seen that if the inclination angle θ is set to about 35 ° or more, it is good for increasing the rigidity. For this reason, in the embodiment of the present invention, θ is set to 35 ° or more, so that the slanted wall portion 21 has a function of increasing rigidity.
Due to this increase in rigidity, the stress is reduced by about 10% to 20%.
It is possible to reduce by 0%.

Next, the structure peculiar to each embodiment of the present invention and the operation thereof will be described. The first embodiment of the present invention is shown in FIGS. 1 and 2, and its configuration and operation are as described above as a common part. In the second embodiment of the present invention, as shown in FIGS. 5 and 6, the wheel 11 has at least one of the wheel axial inner surface 27 and the wheel axial outer surface 28 of the hub mounting portion 14 (see FIG. 5). , Fig. 6
In the above example, the case of both surfaces 27 and 28 is shown), and an annular groove 29 including the bolt hole 17 is formed within the groove width with the wheel shaft center as the center. However, the outer diameter of the groove 29 is the hub 1
It is smaller than the outer diameter of 8. The depth of the groove 29 is 0.2
~ 0.5 mm, preferably about 0.3 mm,
The depth is smaller than the depth of the spherical seat portion 17b of the bolt hole 17.

The function of the groove 29 is as follows. That is, when the hub nut 20 is tightened, a large bolt force is applied to the vicinity of the bolt hole 17, so in the example of the single wheel of FIG.
In the example of the double wheel of FIG. 6, both wheels will hit strongly only in the vicinity of the bolt holes. The contact surface between the wheel 11 and the hub 18 (the example in FIG. 5) or the contact surface between the wheel 11 and the wheel 11 (the example in FIG. 6) due to the bolt tightening force is closer to the outer peripheral portion than only the vicinity of the bolt hole. In a wide width region continuous in the direction, torque transmission and load application are stable. If there is no groove 29, the bolt force tends to be concentrated mainly in the vicinity of the bolt hole 17, but by providing the groove 29, the portion to which the load is applied shifts to the portion without the groove 29 on the outer peripheral side. , Load is applied and torque transmission is stable. Further, since the portion near the bolt hole 17 is not repeatedly subjected to the pressure contact force from the contact surface, it is also effective in preventing fretting.

[0014]

According to the large and medium-sized light alloy wheel of claim 1, since the slant wall portion is provided, the rigidity of the hub mounting portion and the vicinity of the bolt hole is enhanced, and the stress generated at the periphery of the bolt hole is reduced. The durability strength is improved. As a result, it is possible to reduce the thickness of the hub mounting portion and thereby reduce the weight (about 10%). According to the large and medium-sized light alloy wheels of the second aspect, in addition to the effect of the wheel of the first aspect, there is an effect that the way of applying a load is further stabilized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of large and medium light alloy wheels according to a first embodiment of the present invention.

FIG. 2 is a change diagram of stress (related to durability strength) in the vicinity of a bolt hole when the inclination angle θ of a swash wall is variously changed in the wheel of FIG.

FIG. 3 is a front view of a rotary bending fatigue test apparatus.

FIG. 4 is a front view of a radial load durability test apparatus.

FIG. 5 is a sectional view of a large and medium light alloy wheel according to a second embodiment of the present invention when used as a single wheel.

FIG. 6 is a cross-sectional view of a large and medium-sized light alloy wheel according to a second embodiment of the present invention when used in double.

FIG. 7 is a cross-sectional view of conventional large and medium light alloy wheels.

[Explanation of symbols]

 11 Large and Medium Light Alloy Wheels 12 Disc Part 13 Rim Part 14 Hub Mounting Part 15 Curved Part 16 Hub Hole 17 Bolt Hole 21 Sloping Wall Part 29 Annular Groove

Continuation of the front page (72) Inventor Shunji Kobayashi, Topy Kogyo Co., Ltd. 9-5 Yonbancho, Chiyoda-ku, Tokyo

Claims (2)

[Claims] 1. A casting type large or medium-sized light alloy wheel having a disc portion and a rim portion, the disc portion having a hub mounting portion and a curved portion extending between the hub mounting portion and the rim portion. In the above, the hub mounting portion and the curved portion are connected via a sloping wall portion inclined by 35 ° or more inward in the wheel axial direction with respect to a radial extension line of the hub mounting portion. Medium size light alloy wheel. 2. The large and medium-sized mold according to claim 1, wherein an annular groove centering on the wheel shaft center and including a bolt hole is formed on at least one of the inner and outer surfaces of the hub mounting portion in the wheel shaft direction. Light alloy wheel.