JP4529527B2 - Automotive road wheel - Google Patents

Description

  The present invention relates to an automobile road wheel that reduces in-vehicle noise and vibration caused by road noise.

While the vehicle is traveling, vibration generated between the tire and the road surface is transmitted to the vehicle body via the road wheel and suspension. This vibration is called road noise and causes noise and vibration in the vehicle interior.
Since a road wheel in the road of transmission of road noise generally has a natural frequency in a band of 200 to 300 Hz, when vibration in this band is input from the tire to the road wheel, it is coupled with resonance with the road wheel itself. Thus, it is known that the vibration transmission becomes particularly large and the in-vehicle noise deteriorates.
Further, in the band of 200 to 300 Hz, it also matches the natural frequency of the tire, and the vehicle interior noise may be further deteriorated due to vibration transmission due to tire cavity resonance.
Therefore, increasing the rigidity of the road wheel to increase the natural frequency beyond the 200 to 300 Hz band is effective in reducing noise and vibration in the vehicle interior.

By the way, during the above-described resonance of the road wheel, a “surface collapse phenomenon” as shown in FIG. 7A due to torsion and bending is prominent in a plurality of radial spoke portions connecting the hub portion and the rim portion of the wheel. Note that the road wheel in FIG. 7A exaggerates the deformation of the spoke portion in order to make the torsion and curvature clear at a glance.
Specifically, it is effective to increase the rigidity of the spoke portion as a countermeasure for reducing the vibration transmission of the road wheel so that the “face collapse phenomenon” occurs in a band of 400 Hz or higher. The thing as described in patent document 1 is known. The vehicle wheel described in Patent Document 1 is provided with a pair of spoke portions on both sides of each hub bolt hole, and a cross-sectional area perpendicular to the longitudinal direction of these spoke portions is configured to increase toward the hub portion, and a plurality of radial spoke portions. The surface tilt phenomenon is caused by vibrations of 400 Hz or higher.
JP 2002-293101 A

However, the conventional vehicle wheel has the following problems.
That is, first, since it can be applied only to a road wheel having a pair of spoke portions on both sides of each hub bolt hole, it is necessary to provide the number of spokes twice as large as the hub bolt hole, and the design restrictions are increased and the embodiment is implemented. Is limited.

  In addition, when the cross-sectional area of the spoke part is increased as it approaches the hub part, the cross-sectional area is constantly reduced toward the rim part over the entire longitudinal direction of the spoke part. I confirmed.

  First, prior to explaining this problem, technical considerations obtained as a result of further research on the above-described “face-down phenomenon” by the inventor will be described.

  As shown in FIG. 7 (a), the surface collapse phenomenon is a phenomenon in which spoke portions arranged radially between the hub portion and the rim portion vibrate and deform with a waveform having an amplitude in the wheel rotation axis direction. This deformation can be modeled as a three-point support beam as shown in FIG. In FIG. 7B, H is a hub portion, O is a wheel rotation shaft, R is a rim portion, and S is a spoke portion on the wheel diameter. The spoke portion S in which the surface collapse phenomenon occurs can be expressed in a model in which both ends and the center are supported by pins and a moment M is applied to the center.

ここで、Ｌははりの全長、ｘははりの自由端から長手方向の距離、Ｒ_Ｏははりの固定端の断面の半径、ｒははりの自由端から距離ｘの位置における断面半径とする。これよりはりの表面は、長手方向にわたって３次関数の放物線となる。 When attention is paid to the spoke portion S having a radius among the spoke portions S having a diameter shown in FIG. 7B, the hub side is a fixed end and the rim side is a free end as shown in FIG. 7C. This is equivalent to a model in which a force F obtained by dividing the moment M by the spoke length L acts on the free end of the cantilever.
The optimal solution of the cantilever beam (the three-dimensional shape of the beam that can obtain a large rigidity with a small volume against the force acting on the free end) is shown in the cross section of the beam as shown in FIG. The cross-sectional shape is a circle (radius is indicated by R _o and r), and the radius is smaller on the free end side than on the fixed end side. Moreover, the longitudinal cross-sectional shape can be represented by a figure as shown by a solid line in FIG.

Here, L is the total length of the beam, x is the distance in the longitudinal direction from the free end of the beam, R _O is the radius of the cross section of the fixed end of the beam, and r is the cross sectional radius at the position x from the free end of the beam. The surface of the beam becomes a parabola of a cubic function over the longitudinal direction.

式（２）よりＹは、

となる。 Next, in order to consider the solid cylinder shown by the one-dot chain line in FIG. 8B having the same volume V and full length L as the above cantilever beam and having a constant cross-sectional shape, the cross-sectional radius Y of the beam is obtained. .
First, the volume V can be obtained from the following equation.

From equation (2), Y is

It becomes.

  According to FIG. 8B in which the above-mentioned cantilever beam and a solid cylindrical beam having a cross-sectional radius Y are overlapped so that the respective axes coincide with each other, in designing the spoke portion S, the hub side It is understood that the rigidity of the rim side is increased and the rigidity cannot be improved so much even if the cross-sectional area of the rim is increased.

を代入することにより、距離Ｘｅを求めることができ、

となる。 Here, to obtain the distance Xe from the free end of both beams to the position where the cross-sectional shape of the cantilever and the cross-sectional shape of the solid cylinder coincide with each other, the above equation (1) is used.

By substituting, the distance Xe can be obtained,

It becomes.

ここで、Ｄ_Ｏははりの固定端における厚さの半分値、ｄははりの自由端から距離ｘの位置における厚さの半分値とする。これよりはりの表面は、長手方向にわたって２次関数の放物線となる。 In addition, if the above-mentioned optimal solution (the three-dimensional shape of a beam capable of obtaining a large rigidity with a small volume against the force acting on the free end) is added, as shown in FIG. In the optimum solution when the beam is wedge-shaped with a constant width over its entire length, the thickness of the beam is smaller on the free end side than on the fixed end side. Further, the cross-sectional shape can be expressed by the following equation as shown by a solid line in FIG.

Here, D _O half value of the thickness at the fixed end of the beam, d is the half value of the thickness at the position of distance x from the free end of the beam. The surface of the beam becomes a parabola of a quadratic function over the longitudinal direction.

となる。 Next, the optimal solution in the case of a wedge shape has the same volume V and total length L as a cantilever beam, and a rectangular parallelepiped indicated by a one-dot chain line in FIG. If the distance Xe to the position where

It becomes.

That is, regardless of the solid shape shown in FIG. 8 or the wedge shape with a constant width shown in FIG. 9, the distance Xe to the position where the cross-sections coincide is substantially the same value.
The shape of the beam should be thin at the free end while ensuring a substantially constant thickness at the fixed end, and even if the free end is thickened, the rigidity of the beam is increased only by increasing the weight of the beam. I can't expect it.

  Therefore, in consideration of the above technical considerations, in the conventional road wheel in which the cross-sectional area perpendicular to the longitudinal direction of the spoke portion is reduced constantly over the entire longitudinal direction of the spoke portion as described above, If the rim side cross-sectional area does not contribute to the rigidity, the rim side cross-sectional area will increase more than necessary, leading to an increase in the weight of the road wheel. The rigidity cannot be made as required, and there is a problem that these weight and rigidity requirements cannot be satisfied.

  An object of the present invention is to propose an automobile road wheel capable of reducing road noise while solving the above-described problems related to the balance between weight and rigidity of the conventional road wheel based on the above technical considerations. And

For this purpose, an automobile road wheel according to the present invention comprises, as described in claim 1, a plurality of spokes whose longitudinal direction is the wheel radial direction, and the hub portion at the center of the wheel and the rim portion on which the tire is mounted. in automotive road wheel linked in part, the inner surface of the spoke to be the inward practical state of road wheel and the flat surface, said inner surface to said rim portion to the ribs in a vehicle width from the hub portion While gradually decreasing the height towards
Reinforcing ribs that connect the hub portion and the rim portion are provided so as to be greatly reduced as the rim portion is approached.

According to the automotive road wheels according the present invention, the inner surface of the spoke portion to the flat surface, on the inner surface, while gradually reducing the height toward the vehicle width inwardly of the rib toward the rim portion from the hub portion, Since the reinforcing ribs that connect the hub and the rim are greatly reduced as they approach the rim, the rigidity of the road wheel that causes the "face collapse phenomenon" is increased while minimizing the increase in weight. The natural frequency can be increased.
Therefore, according to the present invention, it is possible to solve the problem relating to the balance between the weight and rigidity of the road wheel, contribute to weight reduction of the road wheel, and reduce vehicle interior noise.

Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.
FIG. 1 is a perspective view of an automobile road wheel according to an embodiment of the present invention as viewed obliquely inward in the vehicle width direction.
The hub portion 2 at the center of rotation of the automobile road wheel 1 is provided with a plurality of hub bolt holes 3 to be attached to an axle member (not shown) at equal distances from the center holes 11 provided on the wheel rotation shaft. Drill.
In the practical state where the road wheel 1 is attached to the vehicle, the end surface of the hub portion 2 shown in FIG. 1 is directed inward in the vehicle width. Hereinafter, the side toward the inside of the vehicle width is referred to as the inner side.
The side facing the outer side in the practical state in which the road wheel 1 is attached to the vehicle opposite to the inner side is referred to as the outer side.

A hollow cylindrical rim portion 4 for mounting a tire (not shown) is formed on the outer periphery of the automobile road wheel 1. The outer peripheral side 4o of the peripheral part of the rim part 4 and the outer periphery of the hub part 2 are integrally coupled by a plurality of spoke parts 5 whose longitudinal direction is the road wheel radial direction.
In order to reinforce the bending strength of the spoke portion 5, a rib 6 having a constant width is provided on the inner surface 5 i toward the inner side of the surface of the spoke portion 5 so as to extend in the longitudinal direction at the center in the width direction. Flange 7 is provided on both side edges of the spoke portion 5 over the entire length in the longitudinal direction.

FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1 and viewed from the direction of the arrow, and shows a cross-sectional shape perpendicular to the longitudinal direction of the spoke portion 5. The AA cross section is a cross section of the spoke portion 5 at the intermediate portion between the hub portion 2 and the rim portion 4.
The side edge 7 s of the flange 7 is bent toward the inner side and coincides with the height of the rib 6.
Further, in the cross-sectional shape, the outer surface 5o of the spoke portion 5 may be a substantially flat surface as shown in FIG. 2 (a), or a convex curved surface protruding toward the outer side as shown in FIG. 2 (b). Alternatively, as shown in FIG. 2 (c), it may be a concave curved surface recessed toward the inner side, and it is possible to provide a degree of freedom in design.

  FIG. 3 is a cross-sectional view of the automobile road wheel 1 shown in FIG. 1 taken along the B-B plane, and this cross section is seen from the direction of the arrow, and the rim passes from the hub portion 2 through the spoke portion 5 in the longitudinal direction. A longitudinal section up to the part 4 is shown.

The inner surface 5i and the outer surface 5o are substantially parallel planes , and the thickness of the spoke portion 5 body is substantially uniform. In addition, the inner surface 5ic is slightly inflated toward the inner side at the intermediate portion between the hub portion 2 and the rim portion 5 to slightly increase the thickness of the spoke portion 5 body, but this acts on the spoke portion 5 body. This is based on the analysis result of distributing the stress to be distributed.
The rib 6 extends from the joint portion 8 between the hub portion 2 and the spoke portion 5 to the outer peripheral side, reaches the joint portion 10 between the spoke portion 5 and the rim portion 4, and the end portion of the rib 6 on the hub portion 2 side. And the edge part by the side of the rim | limb part 4 has joined the hub part 2 and the rim | limb part 4, respectively.

Since the rib 6 is erected on the inner surface 5i facing inward of the vehicle width, the rib 6 protrudes toward the inner side. This protruding amount is called the height of the rib.
The rib height (distance H ₁ between 8 and 6h) at the joining point 8 is equal to the rib height (10 and 6r) at the end of the rib 6 far from the joining point 8 (the joining point 10 in this embodiment). distance H ₂₎ higher than a higher rigidity of the hub portion 2 side than the rigidity of the rim portion 4 side of the spoke portion 5.
Further, the height of the portion 6rr of the rib 6 on the rim portion 4 side protrudes toward the inner side from the alternate long and short dash line connecting the height position 6h of the rib 6 at the joint 8 and the height position 6r of the rib end. The wedge 6 shown in the above formula (6) and FIG.

  In order to make the rib 6 have a shape closer to the above-mentioned wedge shape, the height is reduced at the intermediate position in the longitudinal direction of the spoke part 5 corresponding to the distance Xe in the above-described equation (5) and FIG. The start location 9 is provided, and the height of the rib 6 is further reduced with the height reduction start location 9 as a boundary. In other words, the height of the rib 6 starts to decrease from the connecting portion 8 in the longitudinal direction. On the other hand, on the rim portion 4 side of the height reduction start location 9, the height is further lowered as the rim portion 4 is approached, and the height of the rib 6 is increased in the vicinity of the joint location 10 with the rim portion 4 that is the end of the rib 6. Make it the lowest.

Specifically, the height of the rib 6 is expressed as a quadratic curve of the equation (6) or a cubic curve of the equation (1) from the joining point 8 to the height reduction starting point 9, but in practice it is almost The height of the rib 6 is made slightly lower like 6b so as to be gradually reduced like a straight line, or to secure a gap with the brake caliper provided facing the inner surface 5i as shown in FIG. As shown in FIG. 2 described above, the height of the flange side edge 7s and the height of the rib 6 coincide from the height reduction start point 9 to the hub portion 2 (rib height position 6h).
The height of the rib 6 on the side of the rim 4 from the height reduction starting point 9 is a parabola such as a quadratic curve of the formula (6) or a cubic curve of the formula (1), and the above-described one-dot chain line in FIG. On the other hand, the height of the rib 6 is smoothly reduced while the end portion 6rr protrudes toward the inner side. In the end height position 6r, a fillet portion 6c is provided to prevent metal fatigue and fracture due to stress concentration between the end portion 6rr and the rim portion 4 so that the end portion 6rr and the rim portion 4 are smooth. To join.

  The position of the height reduction start location 9 is determined based on the results of the above-described formulas (5) and (6), and the inner surface 5i of the spoke portion 5 and the coupling location 8 between the hub portion 2 and the inner surface 5i of the spoke portion 5. And an intermediate position between the rim portion 4 and the joint 10.

If it adds here, the road wheel 1 of this invention provided the rib 6 extended in the longitudinal direction in the inner surface 5i of the spoke part 5, and was obtained as a result of the technical examination which said height of the rib 6 mentioned above ( These formulas are determined based on the formula (1) or formula (6), but these formulas are only a numerical model for explaining the gist of the technical considerations described above, and the formulas (1) or ( 6) It is not necessary to match the equation. In other words, the above-mentioned technical consideration results indicate that the rigidity of the spoke portion 5 is substantially constant on the fixed end side (hub portion 2 side) and the spoke portion 5 on the free end side (rim portion 4 side). That is, the rigidity should be lowered.
By determining the height of the rib 6 on the basis of this fact, it is possible to solve the above-described problem relating to the balance between the weight and rigidity of the conventional road wheel. Therefore, for example, when the height of the rib 6 cannot be sufficiently secured due to the layout when the road wheel 1 is attached, it is a matter of course that the rigidity of the rib 6 may be secured by increasing the width of the rib 6.

Further, based on this effect, in addition to the present embodiment in which the rib 6 is erected over the entire longitudinal direction of the spoke portion 5 as shown in FIG.
As shown in the perspective view of FIG. 4, the end 6 e of the rib 6 is connected to the joint portion 8 between the inner surface 5 i of the spoke portion 5 and the hub portion 2 and the joint portion 10 between the inner surface 5 i of the spoke portion 5 and the rim portion 4. You may extend to the intermediate part in between. FIG. 4 is a perspective view of the spoke portion 5 as seen from the inner side, and is schematically shown for explaining the feature of the shape of the rib 6. The height of the rib 6 is set at the hub portion 2 side portion of the rib 6. As the rim part 4 is approached, it gradually decreases, and at the rim part 4 side portion of the rib 6, the height of the rib 6 is reduced more greatly than the hub part 2 side portion as it approaches the rim part 4.
In FIG. 4, it is an intermediate position of the spoke portion 5, a position on the outer peripheral side by a distance La of 40% of the total length Ls of the spoke portion 5 from the joint portion 8, and a distance of 60% of the total length Ls of the spoke portion 5 from the joint portion 8. A height reduction start point 9 is provided in a section between Lb and the position on the outer peripheral side.
The end 6 e on the rim portion 4 side is between the height reduction start portion 9 and the joint portion 10 between the inner surface 5 i and the rim portion 4.
Further, the height of the rib 6 is further reduced at the end portion 6rr between the height reduction start portion 9 and the end portion 6e on the rim portion 4 side as shown by the arrow in FIG. It is configured to be a parabola that is inflated.

FIG. 5A is an enlarged perspective view showing the shape of the rib 6 from the height reduction start point 9 to the terminal end 6e shown in FIG. 4, and on the rim part 4 side from the height reduction start point 9, As the rim portion 4 is approached, the height H of the rib 6 is lowered. The rib width B is constant.
In addition, as shown in FIG. 4 (a), as shown in FIGS. 4 (b) to 4 (d), the rib width B is increased toward the rim portion 4 side on the rim portion 4 side than the height reduction starting portion 9. It may be small.
That is, as shown in FIG. 4B, the decreasing rate of the rib width B may be reduced toward the rim portion 4 side, and the end 6e may be extended toward the rim portion 4 side. Alternatively, as shown in FIG. 4 (c), the decreasing rate of the rib width B may be increased toward the rim portion 4 and the end 6e may be rounded toward the rim portion 4 side. Alternatively, as shown in FIG. 4D, the reduction rate of the rib width B may be constant, and the end 6e may be sharpened toward the rim 4 side. Further, the rib width B may be left at the end 6e as shown in FIGS. 4A and 4B, or the rib width on the rim portion 4 side as shown in FIGS. 4C and 4D. The end 6e may be sharpened so that B becomes zero.

  By the way, in the present embodiment, ribs 6 for reinforcing the spoke portion 5 are erected on the inner surface 5i from the connecting portion 8 to the hub portion 2 of the spoke portion 5 having a great influence on the rigidity of the road wheel 1 in the longitudinal direction. Set up. The height of the rib 6 at the joint 8 is set higher than the height 6r of the rib 6 at the end of the rib 6 far from the joint 8 (or the height of the end 6e). Then, the height of at least the end portion 6rr of the rib 6 is configured so as to be a parabola that protrudes toward the inner side from the alternate long and short dash line in FIG. 3, and the width of the rib 6 is reduced. Since it is configured to be larger than the bubb part 2 side, it is possible to increase the rigidity of the road wheel 1 while minimizing an increase in the weight of the road wheel 1, and to satisfy both requirements of weight and rigidity. .

Further, as shown in FIG. 3, the rib 6 extends from the hub portion 2 to the rim portion 4, and the height of the rib 6 with respect to the alternate long and short dash line is set so as to be recessed toward the outer side at the hub portion 2 side 6b. The height of the rib 6 is such that the rib 6 protrudes toward the inner side, and the width of the rib 6 is increased on the hub 2 side and decreased on the rim 4 side.
Based on the above technical considerations, the rigidity of the spoke part 5 is kept substantially constant on the fixed end side (hub part 2 side), while the rigidity of the spoke part 5 is reduced on the free end side (rim part 4 side). It is possible to increase the rigidity of the road wheel 1 while minimizing the increase in the weight of the road wheel 1 and to satisfy both the requirements of weight and rigidity. Moreover, a clearance can be ensured between the brake caliper provided on the inner side of the road wheel 1 and the rib 6 to prevent mutual interference.

Also, as shown in FIGS. 3 and 4, the height of the rib 6 starts to be reduced from the joining portion 8 in the longitudinal direction of the spoke portion 5, and this reduction amount is from the joining portion 8 to the joining portion 8 and the joining portion 10. By increasing the amount of reduction from the height reduction start point 9 to the rim part 4 side, compared to the amount of reduction up to the height reduction start point 9 provided in the middle part,
Based on the above technical consideration results, the rib 6 can be effectively shaped like the wedge shown in FIG.

In the present embodiment, the road wheel 1 has five spoke portions 5, but the number of spokes is not limited to five when the rib shape of the present invention is implemented. For example, it may be a three-type road wheel having three spoke portions with a large circumferential width (cross-sectional area) as shown in FIG. 6A, or a spoke portion with a small circumferential width (cross-sectional area). It may be an eight-type road wheel as shown in FIG.
Further, the overall length of the spoke portion 5 is not limited to the present embodiment. For example, when implementing the rib shape of the present invention, the overall length in the wheel radial direction of the spoke portion 5 is relatively short as shown in FIG. A dish-type road wheel 1 may be used.
Further, in the present embodiment, one rib 6 is provided upright per one spoke portion 5, but it goes without saying that even if a plurality of ribs are provided, both weight and rigidity, which are the effects of the present invention, are realized.

It is the perspective view which looked at the road wheel for vehicles used as the example of the present invention from the slant inner side in the vehicle width direction. FIG. 2 is a cross-sectional view of the spoke portion taken along a plane AA in FIG. 1 and this cross section is viewed from the direction of an arrow, wherein (a) shows the present embodiment, (b) and (c) Other embodiments will be described. It is the longitudinal cross-sectional view which made the same road wheel into a cross section in the BB surface in FIG. 1, and saw this cross section from the direction of the arrow. It is the schematic diagram which looked at the spoke part of the road wheel for vehicles used as other examples of the present invention from the slanting inward direction of the vehicle width. It is a perspective view which expands and shows the rib termination | terminus part of the spoke part, (a) is the other Example shown in FIG. 4, (b), (c), (d) is another Example An example is shown. It is the front view which looked at the road wheel for vehicles which serves as another example of the present invention from the vehicle width direction, (a) is another example which has three spoke parts, (b) is eight spokes (C) shows the other Example which has six spoke parts. It is a figure which shows the "surface collapse phenomenon" which arises in a spoke part, (a) is a perspective view which exaggerated and expressed a spoke part in order to make twist and a curve clear, (b) is a three-point support beam. Modeled diagram, (c) is a model modeled as a cantilever. It is a figure which shows the optimal three-dimensional shape of the same cantilever, (a) is a perspective view, (b) is the same volume and the same full length as the cantilever, and is a cross-sectional area. It is a top view shown superimposed on a fixed solid cylindrical beam. It is a figure which shows the optimal wedge shape of the same cantilever, (a) is a perspective view, (b) is the same volume and the same full length as the cantilever and the cross-sectional area is constant. It is a top view shown superimposed on the rectangular beam.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Road wheel 2 Hub part 3 Hub bolt hole 4 Rim part 5 Spoke part 5i Inner surface of a spoke part 6 Rib 7 Flange 9 The height reduction start part of a rib

Claims (3)

In an automobile road wheel in which a hub portion in a wheel center portion and a rim portion on which a tire is mounted are coupled by a plurality of spoke portions whose longitudinal direction is a wheel radial direction,
The inner surface of the spoke to be the inward practical state of road wheel and the flat surface, gradually reducing the height toward the vehicle width inwardly of the ribs from the hub portion to said inner surface toward said rim portion On the other hand, the automobile road wheel is provided with a reinforcing rib for connecting the hub portion and the rim portion so as to be greatly reduced as the rim portion is approached. The height of the rib on the side of the rim portion is set to be higher than the line connecting the rib height position of the connecting portion between the spoke inner surface and the hub portion and the height position of the connecting portion between the inner surface and the rim portion. The automobile road wheel according to claim 1, wherein the vehicle road wheel has a height that protrudes inward in the width direction. The rib extends from the hub portion to the rim portion, and the height of the rib on the hub portion side is set so that the rib height position, the inner surface and the rim at the connecting portion between the spoke portion inner surface and the hub portion. The height is such that it is recessed outward in the vehicle width direction from the line connecting the height positions of the joints between the parts ,
The height of the rib on the side of the rim portion is set to be higher than the line connecting the rib height position of the connecting portion between the spoke inner surface and the hub portion and the height position of the connecting portion between the inner surface and the rim portion. The automobile road wheel according to claim 1, wherein the vehicle road wheel has a height that protrudes inward in the width direction.

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