JP4449209B2 - Automotive road wheel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automobile road wheel, and more particularly to an automobile road wheel having improved sound vibration performance without substantially reducing steering stability.
[0002]
[Prior art]
In general, an automobile road wheel is attached to an axle part connected to a vehicle body via a suspension or the like by fastening its disk part with a bolt and a nut so as to achieve both steering stability and sound vibration performance. I was doing. However, in recent years, with the advancement of luxury in passenger cars, there has been a strong demand for further improvement in sound vibration performance such as riding comfort and road noise.
[0003]
As a countermeasure against such a request, Japanese Patent Application Laid-Open No. 6-344703 discloses spot welding between a disc portion and a rim portion separated from each other at a plurality of locations in the circumferential direction, and viscoelasticity such as asphalt or rubber on a non-welded portion. We are proposing a road wheel that suppresses vibration by interposing a substance. However, according to this measure, it is necessary to prepare the disk part and the rim part as independent parts, so the existing wheel cannot be used, and a new mold has to be generated as a dedicated wheel. Therefore, the manufacturing cost is high and the design is limited.
[0004]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide an automobile road wheel that improves sound and vibration performance without substantially reducing steering stability by only partially modifying the structure of an existing road wheel.
[0005]
[Means for Solving the Problems]
The present invention that achieves the above object provides a vehicle road wheel in which a disk part is fixed to a vehicle axle part with a fastener, and a fastening portion where the disk part is fixed with a fastener is provided between an outer cylinder and an inner cylinder. The outer cylinder is fixed to the disk part by interposing a vibration isolation mechanism including a vibration damping material, the inner cylinder is fixed to the axle part side by the fastener , and the damping The vibration damping material A is composed of a vibration damping material A at a location sandwiched in the axial direction of the fastener and a vibration damping material B at a location sandwiched in a direction orthogonal to the axial direction, and the elastic modulus of the vibration damping material A is by the large than the elastic modulus of the damping material B, the movable displacement δb when applying a load in a direction perpendicular to the axial direction of said fastener relative-proof vibration mechanism, in the axial direction Larger than the displacement δa when the same load is applied It was Ku becomes way is characterized in.
[0006]
In this way, an anti-vibration mechanism is interposed at the place where the disk part is fastened to the vehicle axle part, and the outer cylinder is fixed to the disk part, and the inner cylinder is fixed to the axle part side with the fastener, The vibration damping material is composed of a vibration damping material A at a location sandwiched in the axial direction of the fastener and a vibration damping material B at a location sandwiched in a direction orthogonal to the axial direction. Is made larger than the elastic modulus of the damping material B , the vibration damping mechanism attenuates the vibration transmitted from the tire to the axle portion through the disk portion, thereby improving the sound vibration performance. Moreover, since the axial displacement at the fastening portion is small, the steering stability is not substantially lowered.
[0007]
In addition, since the vibration isolation mechanism can be installed by simply modifying a part of the existing road wheel structure, the existing road wheel mold can be used as it is, and it can be manufactured at low cost.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the vibration isolating mechanism is composed mainly of a vibration damping material. The vibration damping material is not particularly limited as long as it has a characteristic of attenuating vibration conducted from the road wheel to the axle portion. For example, rubber, thermoplastic resin, rubber is added to the thermoplastic resin. The blended thermoplastic resin elastomer composition etc. can be mentioned. Further, if necessary, the damping steel plate can be used as a damping material.
[0009]
The rubber used for the vibration damping material is not particularly limited, and may be any of synthetic rubber and natural rubber. The thermoplastic resin is not particularly limited as long as it has vibration damping characteristics.
[0010]
The thermoplastic resin elastomer composition is a composition having viscoelastic properties obtained by blending rubber with a thermoplastic resin. In particular, a thermoplastic resin having a tan δ peak in the range of 0 ° C. to 150 ° C. is used as a continuous phase, and at least a part of the continuous phase is crosslinked and a tan δ peak in the range of −100 ° C. to 0 ° C. Those in which a rubber component having a water content is dispersed are preferred. Here, the temperature showing the peak of tan δ is the temperature at which the temperature dependence curve of tan δ is obtained under the condition of 20 Hz based on JIS K7198, and the curve shows the peak.
[0011]
Examples of the rubber used in the thermoplastic resin elastomer composition include butyl rubber, olefin rubber, and natural rubber. Examples of the thermoplastic resin include polyamide resins, polypropylene resins, and polyester resins.
[0012]
The structure of the vibration isolation mechanism used in the present invention uses a structure in which a vibration damping material is integrally joined between the outer cylinder and the inner cylinder . Moreover, it is preferable that the damping material is integrally bonded to the outer cylinder and the inner cylinder by baking or using an adhesive. Although the above-described materials are used as the vibration damping material, metals such as steel and aluminum, fiber reinforced resin, and the like can be used for the outer cylinder and the inner cylinder. Such an integral structure composed of an outer cylinder, a damping material and an inner cylinder presses the outer cylinder into the disk portion of the road wheel, and fixes the inner cylinder to the axle portion of the vehicle with fasteners such as bolts and nuts. It is attached in this way.
[0013]
In addition, the vibration isolation mechanism has a movable displacement amount δb when a load is applied in a direction orthogonal to the axial direction of the fastener (vertical direction in the vehicle), and the same load is applied in the axial direction (horizontal direction in the vehicle). If set to be larger than the movable displacement δa when given. Since the movable displacement amount δb in the direction perpendicular to the axial direction of the fastener is large as described above, the ride comfort and road noise are reduced, and the movable displacement amount δa in the axial direction of the fastener is small. It can be maintained well so as not to deteriorate the steering stability.
[0014]
As a means for obtaining such characteristics, as the damping material interposed between the outer cylinder and the inner cylinder, the elastic modulus of the damping material A sandwiched in the axial direction of the fastener and the direction orthogonal to the axial direction to be different from each other and an elastic modulus of the damping material B sandwiched, and that makes us by to the larger than the elastic modulus of the damping material B an elastic modulus of the damping material a.
[0015]
FIG. 1 shows an example of a basic configuration of an automobile road wheel which is a premise of the present invention.
[0016]
In FIG. 1, 1 is a road wheel with a pneumatic tire T mounted thereon, and 2 is an axle portion of the vehicle. In the road wheel 1, the disk portion 3 and the rim portion 4 are integrally formed, and the axle portion 2 of the vehicle includes an axle 2 a and a hub 2 b.
[0017]
The disk portion 3 of the road wheel 1 is fastened and fixed to the hub 2 b of the axle portion 2 by a fastener 9 via a vibration isolation mechanism 5. The vibration isolating mechanism 5 is configured by integrally bonding a damping material 7 between the outer cylinder 6 and the inner cylinder 8, and the outer cylinder 6 is press-fitted into a hole provided in the disk portion 3. It is fixed clamped to the hub 2b of the axle portion 2 by the cylinder 8 fasteners 9.
[0018]
The fastener 9 includes a planting bolt 9a planted on the hub 2b and a nut 9b screwed into the planting bolt 9a. Further, the hole of the disk portion 3 into which the outer cylinder 6 of the vibration isolation mechanism 5 is press-fitted can be easily processed simply by expanding the bolt hole originally provided in the disk portion with a drill or a reamer. Can do.
[0019]
As described above, when the disc portion 3 of the road wheel 1 is fastened to the vehicle axle portion 2 via the vibration isolation mechanism 5, the pneumatic tire T is transmitted to the axle portion 2 via the rim portion 4 and the disc portion 3. The vibration is attenuated by the vibration isolation mechanism 5 and the amount of vibration transmitted is reduced to improve the sound vibration performance. Further, since the vibration isolating mechanism 5 is fastened to the axle portion 2 in parallel with the axle through the inner cylinder 8, the amount of variable displacement in the axial direction is small, and substantially no decrease in steering stability is recognized.
[0020]
Further, since the vibration isolating mechanism 5 can be equipped with a conventional road wheel only by partially grinding a fastening portion (bolt hole), a mold for a conventional road wheel can be obtained without producing a dedicated road wheel. Can be used as it is, and can be manufactured at low cost. In addition, since a conventional road wheel can be used, there are no design restrictions.
[0021]
Figure 2 is a diagram showing a reference example of anti-vibration mechanism which is interposed road wheels for automobiles.
[0022]
The vibration isolation mechanism 5 shown in FIG. 2 is formed with hooks 6a and 6a that are bent inwardly at both ends of the outer cylinder 6, and the inner cylinder 8 has a central portion formed into a large diameter large portion 8a. The large diameter portion 8a is inserted between the flange portions 6a, 6a of the outer cylinder 6. With the above configuration, the gap 6a of the outer cylinder 6 and the large-diameter part 8a of the inner cylinder 8 partially face each other in the axial direction, and the thickness a of the damping material 7 interposed therebetween is It is smaller than the thickness b interposed in the radial direction with the inner cylinder 8.
[0023]
In this way, the thickness a of the damping material 7 sandwiched in the axial direction between the outer cylinder 6 and the inner cylinder 8 is made smaller than the thickness b sandwiched in the radial direction. Thus, the movable displacement amount δb when a load is applied in a direction orthogonal to the axial direction (vertical direction in the vehicle) is made larger than the movable displacement amount δa when the same load is applied in the coaxial direction (horizontal direction in the vehicle). be able to. Therefore, sound vibration performance can be improved without substantially reducing the steering stability.
[0024]
Figure 3 is a view showing another reference example of the anti-vibration mechanism which is interposed road wheels for automobiles.
[0025]
The anti-vibration mechanism 5 shown in FIG. 3 is obtained by forming a concave hourglass-shaped curved portion 8b at the center of the inner cylinder 8 in the anti-vibration mechanism of FIG.
[0026]
By forming the hourglass-shaped curved portion 8b at the center of the inner cylinder 8 in this way, the volume of the damping material 7 in the radial direction (direction perpendicular to the axial direction) is larger than that of the vibration damping mechanism of FIG. The sound vibration performance can be further improved as compared with the case of FIG.
[0027]
FIG. 4 shows an example of an embodiment of an anti-vibration mechanism interposed in the automobile road wheel of the present invention.
[0028]
This anti-vibration mechanism 5 is provided with two kinds of vibration damping materials 7 having different elastic moduli, and is placed between the flange 6a of the outer cylinder 6 and the large-diameter portion 8a of the inner cylinder 8 in the axial direction. A damping material A having a large elastic modulus is interposed, and a damping material B having a smaller elastic modulus than that of the damping material A is interposed between the outer cylinder 6 and the inner cylinder 8 in the radial direction. is there.
[0029]
As described above, the two types of damping materials A and B (elastic modulus of A> elastic modulus of B) having different elastic moduli are arranged between the outer cylinder 6 and the inner cylinder 8 as described above. The movable displacement amount δb when a load is applied to the vibration mechanism 5 in the direction orthogonal to the axial direction (the vertical direction of the vehicle), and the movable displacement amount when the same load is applied in the coaxial direction (the horizontal direction of the vehicle) It can be larger than δa. Therefore, sound vibration performance can be improved without substantially reducing the steering stability.
[0030]
【Example】
The outer tube and the inner tube and a stainless steel, an anti-vibration mechanism of the damping material and rubber, with their respective different for the structure of Figure 3 (Example 1) and 4 structures (Example 1), the disc Two types of automobile road wheels were produced, with the part fastened to the axle. Further, as a comparison, it was prepared the vibration isolation mechanism automobile Rodohoi Le of not intervening (conventional example).
[0031]
Using these three types of automobile road wheels, riding comfort, road noise, and steering stability were measured by the following evaluation methods, and the results shown in Table 1 were obtained.
[0032]
[Ride comfort, road noise, steering stability]
A pneumatic radial tire of tire size 195 / 65R15 91S is attached to each road wheel for measurement, and five people are trained in riding comfort, road noise, and steering stability when it is attached to all wheels of an FR vehicle. The panelists felt and tested. The evaluation of the test was scored on a 5-point scale.
[0033]
The evaluation was performed using an average value of the remaining three scores excluding the maximum value and the minimum value among the scores of the five panelists. The larger the index, the better.
[0034]
[Table 1]
[0035]
【The invention's effect】
According to the present invention as described above, with the disc portion at a position for fastening to the vehicle axle portion, is interposed an anti-vibration mechanism having the configuration of a vibration damping material is interposed between the outer cylinder and the inner cylinder, wherein The outer cylinder is fixed to the disk part, the inner cylinder is fixed to the axle part side with the fastener, and the vibration damping material A at a position where the vibration damping material is sandwiched in the axial direction of the fastener and the The vibration-damping mechanism is constituted by a vibration-damping material B at a portion sandwiched in a direction perpendicular to the axial direction, and the elastic modulus of the vibration-damping material A is larger than that of the vibration-damping material B. Dampens vibrations transmitted from the tire to the axle through the disc, thereby improving sound vibration performance and lowering the steering stability substantially because the axial displacement at the fastening point is small. There is no. In addition, since the vibration isolation mechanism can be installed by simply modifying a part of the existing road wheel structure, the existing road wheel mold can be used as it is, and it can be manufactured at low cost.
[Brief description of the drawings]
FIG. 1 is a half cross-sectional view showing a reference example of an automobile road wheel as a premise of the present invention.
FIG. 2 is a longitudinal sectional view showing a reference example of an anti-vibration mechanism as a premise of the present invention.
FIG. 3 is a longitudinal sectional view showing another reference example of the vibration isolating mechanism which is a premise of the present invention.
FIG. 4 is a longitudinal sectional view showing an example of a vibration isolation mechanism according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Road wheel 2 Vehicle axle part 2a Axle 2b Hub 3 Disc part 4 Rim part 5 Anti-vibration mechanism 6 Outer cylinder 7 Damping material 8 Inner cylinder 9 Fastening tool 9a Stud bolt 9b Nut

Claims (2)

In the automobile road wheel (1) in which the disc portion (3) is fixed to the vehicle axle portion (2) with the fastener (9), the fastening portion where the disc portion (3) is fixed with the fastener (9) , An anti-vibration mechanism (5) having a structure in which a damping material (7) is interposed between the outer cylinder (6) and the inner cylinder (8) is interposed, and the outer cylinder (6) is inserted into the disk portion ( 3), the inner cylinder (8) is fixed to the axle part (2) side by the fastener (9) , and the damping material (7) is fixed to the shaft of the fastener (9). A damping material A at a location sandwiched in a direction and a damping material B at a location sandwiched in a direction orthogonal to the axial direction, and the elastic modulus of the damping material A is the elastic modulus of the damping material B by the large than, the fastener relative-proof oscillating mechanism (5) a load in a direction perpendicular to the axial direction (9) Automobile road wheel which is made larger than the movable displacement δa when the movable displacement δb is given the same load in the axial direction when was e. The automobile road wheel according to claim 1 , wherein the vibration damping material (7) is a rubber, a thermoplastic resin, or a thermoplastic resin elastomer composition obtained by blending rubber with a thermoplastic resin.