JP2006035987A - Elastic wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastic wheel which can reduce oscillation and a noise level during traveling without causing a considerable deterioration in control stability. <P>SOLUTION: The elastic wheel 1 is provided with a rim 2 and a disk 3. Then the rim to which a tire is attached and the disk which is fixed to an axle shaft are elastically connected to each other through the medium of a connecting means 4 having a damper 8 which absorbs oscillation. The damper 8 is constructed of a composite material containing rubber and codes. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an elastic wheel that can reduce vibration and noise levels during traveling without causing significant deterioration in steering stability.

  As shown in FIG. 12, an elastic wheel has been proposed in which a vibration-absorbing damper c is interposed between a rim a on which a tire is mounted and a disk b fixed to an axle (the following patent document). 1). Such an elastic wheel absorbs vibration input from the road surface to the tire with the damper c and suppresses transmission to the axle. This reduces the vibration noise level of the vehicle. For this reason, the elastic wheel has a small vertical rigidity, which is the rigidity in the vertical direction, as compared with a normal metal wheel.

  By the way, when the vehicle corners, a portion located immediately above the ground contact surface of the damper c receives a lateral force from the tire. In the conventional elastic wheel, since the damper c is made of rubber, the lateral rigidity, which is the rigidity in the rotation axis direction, is small, and the lateral force cannot be sufficiently transmitted to the axle. For this reason, there exists a problem that the steering stability at the time of turning deteriorates.

JP 2003-104001 A

  The present invention has been devised in view of the above problems, and by ensuring a large lateral rigidity while reducing a longitudinal rigidity, vibration during traveling without causing a significant deterioration in steering stability. It aims at providing the elastic wheel which can reduce a noise level.

  The invention according to claim 1 of the present invention is an elastic wheel in which a rim on which a tire is mounted and a disk fixed to an axle are elastically connected via a connecting means having a vibration absorbing damper. The damper is made of a composite material including rubber and a cord.

  According to a second aspect of the present invention, the connecting means is provided on at least one inward flange piece projecting radially inward from the inner peripheral surface of the rim and extending in the circumferential direction, and on the outer peripheral edge of the disc. And at least one outward flange piece facing the inward flange piece in the rotational axis direction of the rim and spaced from the inner peripheral surface of the rim, and the damper includes the inward flange piece and the The elastic wheel according to claim 1, wherein the elastic wheel is formed in a ring shape that is connected to the outward flange piece and extends in a circumferential direction.

  The invention according to claim 3 is the elastic wheel according to claim 2, wherein the damper includes a cord extending in a circumferential direction.

  The invention according to claim 4 is the elastic wheel according to claim 2 or 3, wherein the damper includes a cord extending in the axial direction.

  According to a fifth aspect of the present invention, in the elastic wheel according to any one of the second to fourth aspects, the damper includes a cord extending in a radial direction.

  The invention according to claim 6 is the elastic wheel according to any one of claims 1 to 5, wherein the cord is an organic fiber cord or a steel cord.

  In the elastic wheel of the present invention, the rim on which the tire is mounted and the disk fixed to the axle are elastically connected via a connecting means having a vibration absorbing damper. Therefore, the vibration transmitted from the rim to the disk can be absorbed by the damper, and the riding comfort of the vehicle can be improved and the noise can be reduced. Further, since the damper is made of a composite material including rubber and a cord, the rigidity thereof can be easily adjusted, and the lateral rigidity can be easily increased while the longitudinal rigidity is reduced. Therefore, for example, by adopting such an elastic wheel in a vehicle such as a passenger car, ride comfort and noise performance can be improved without a significant decrease in steering stability.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a cross-sectional view of the elastic wheel 1 of the present embodiment. FIG. 2 is an enlarged view of the main part. The elastic wheel 1 includes a rim 2 on which a tire T is mounted, a disk 3 fixed to an axle, and a connecting member 4 for elastically connecting the rim 2 and the disk 3.

  The rim 2 includes a pair of rim seats 2a and 2a on which a bead portion of the tire T is seated, and a flange portion extending radially outward from an outer end of each rim seat 2a in a rim rotation axis direction (hereinafter simply referred to as an axial direction) 2b and 2b, and a well 2c having a small outer diameter provided between the rim sheets 2a and 2a, and the cross-sectional shape shown in FIG. 1 is substantially continuous in the circumferential direction. In the present embodiment, a so-called deep bottom rim in which the outer diameter of the well 2c is smaller is shown as the rim 2 for automobiles, but a shallow rim or a flat bottom rim may be used. The rim 2 is made of a substantially non-extensible metal material such as iron, aluminum alloy or magnesium alloy.

  The disk 3 is fixed to an axle D of a four-wheeled vehicle, for example. The axle D includes a shaft main body D1 and a hub D2 provided at the tip thereof. A hub bolt B for attaching a wheel is provided on the hub D2 so as to protrude outward from the vehicle. A plurality of hub bolts B are provided on a circumference having a diameter (PCD) standardized in advance from the center of the shaft body D1, for example.

  The disc 3 includes a central portion 3a attached to the hub D2 and an outer portion 3b extending radially outward from the central portion 3a. The center portion 3a of the disk 3 is provided with a center bore 12 at the center thereof and a bolt hole 13 corresponding to the hub bolt B around the center bore 12 respectively. The central portion 3a is incorporated in the hub D2. A hub nut 14 is fastened to the hub bolt B that protrudes outward from the bolt hole 13. As a result, the disk 3 is integrally fixed to the axle D.

  The outer portion 3b of the disk 3 extends radially outward from the inner portion 3a. In order to increase the rigidity, the outer portion 3b can be appropriately curved. In order to reduce the weight, the outer portion 3b is processed into a spoke shape provided radially or a mesh shape using a wire, and an appropriate cavity portion is provided. As with the rim 2, the disk 3 is formed of a substantially non-stretchable metal material such as iron, aluminum alloy, or magnesium alloy. Reference numeral BR denotes a brake rotor that is sandwiched and mounted between the hub D2 and the central portion 3a.

  In the present embodiment, the connecting means 4 is provided on at least one inward flange piece 5 protruding radially inward from the inner peripheral surface 2 i of the rim 2 and extending in the circumferential direction, and on the outer peripheral edge of the disk 3. At least one outward flange piece 7 which is axially opposed to the inward flange piece 5 and is spaced apart from the inner peripheral surface 2i of the rim 2, and the inward flange piece 7 and the outward flange piece 5 The thing including the damper 8 for vibration absorption which connects between is illustrated.

  The inner peripheral surface 2i of the rim is a surface opposite to the side on which the tire T of the rim 2 is mounted. In the present embodiment, on the inner peripheral surface 2i of the rim 2, a plurality of, in this example, two inward flange pieces 5, 5 are provided at both sides of the rim width center line RC. The inward flange piece 5 protrudes inward in the radial direction with a predetermined length, and continuously extends in the circumferential direction in this example. Thus, a groove-like space O extending in the circumferential direction is formed by the two inwardly facing flange pieces 5 and 5 and the inner peripheral surface 2i of the rim 3 therebetween. The inner end face of the inward flange piece 5 describes a circle having an inner diameter Ra.

  The inward flange piece 5 may be formed separately from the rim 2, for example, and then fixed to the rim 2 by welding or screwing, or may be integrally formed with the rim 2. Moreover, the inward flange piece 5 is not limited to the aspect which continues completely in the circumferential direction, and may be arcuate. In this case, the inward flange piece 5 is desirably provided intermittently on the inner peripheral surface 2 i of the rim 2.

  When there are a plurality of inward flange pieces 5, it is desirable that at least one of them be configured as a split-type inward flange piece 6 that can be divided, for example, so as to change the protruding height inward in the radial direction. The split-type inward flange piece 6 of the present embodiment includes a root portion 5a that protrudes inward in the radial direction and extends in the circumferential direction with a small height fixed to the inner peripheral surface 2i of the rim 2, and a fixture on the root portion 5a. It is comprised from the ring main body 5b provided detachably using 5c. For example, a bolt or the like is suitable as the fixture 5c. It is desirable that the maximum inner diameter Rc of the root portion 5a is larger than the inner diameter Ra of the inward flange piece 5 and substantially the same as or larger than the maximum outer diameter Rb of the outward flange piece 7 of the disk 3.

  The outward flange piece 7 is integrally provided on the outer peripheral edge of the outer side portion 3 b of the disk 3. In this example, the outer peripheral edge of the disk 3 also serves as the outward flange piece 7. Further, the outward flange piece 7 of the present embodiment is substantially parallel to the tire radial direction and extends continuously in the circumferential direction. Preferably, the end face of the outward flange piece 7 is smoothly chamfered. An outer diameter Rb of the outward flange piece 7 is formed larger than an inner diameter Ra of the inward flange piece 5. However, the outer diameter Rb is smaller than the inner diameter Rr of the inner peripheral surface 2i of the rim in the space O between the inward flange pieces 5, 5. The axial width Wa of the outward flange piece 7 is smaller than the width W of the void O. For this reason, as shown in FIG. 2, in a state where the axial centers of the rim 2 and the disk 3 are aligned, the outward flange piece 7 is retained in the space O while being axially and radially disengaged. Can be located with movable play. This play is appropriately set based on the load applied to the tire, the rigidity of the damper 8, and the like.

  The damper 8 connects between the inward flange piece 5 and the outward flange piece 7 facing each other in the axial direction of the rim, and extends in the circumferential direction. As shown in FIG. 2, in this embodiment, dampers 8 are provided on both sides of the outward flange piece 7. The damper 8 has a flat rectangular cross section that is long in the axial direction, for example, and is formed in a ring shape that is continuous in the circumferential direction as shown in FIG. Both side surfaces of the damper 8 are firmly fixed to the flange pieces 5 to 7 using, for example, vulcanization bonding, screwing and / or adhesive. In this example, the outer surface 8A and the inner surface 8B in the radial direction of the damper 8 are provided as non-restraining surfaces that are not restrained from the outside.

  FIG. 4 shows a cross-sectional view of the damper 8. The damper 8 is made of a composite material including a rubber 8a and a plurality of cords 8b. The damper 8 of this embodiment is exemplified by a cord 8b whose longitudinal direction is arranged along the circumferential direction of the rim 2. Such a damper 8 can be made by vulcanization molding of a ply laminate 10 in which a plurality of cord plies 9 are stacked. The cord ply 9 has a sheet shape composed of a plurality of cords 8b arranged in parallel and unvulcanized rubber 8a covering the cords 8b. The ply laminate 10 includes a cord ply 9 continuously wound as shown in FIG. 5 (A), or a ring-shaped cord ply as shown in FIG. 5 (B). 9 may be repeated. Further, a combination of the methods of FIGS. 5A and 5B may be used.

  In the elastic wheel 1 of the present embodiment, the ring body 5b of the split-type inward flange piece 6 is first removed, and the damper 3 is temporarily fixed to the space O on both sides of the outward flange piece 7 in advance. Is incorporated. Thereafter, the ring main body 5b is attached to the root portion 5a using the fixture 5c. Thus, when one inward flange piece 5 is divided, the ring body 5b is removed from the root portion 5a, whereby the outward flange piece 7 is inserted into the groove-shaped space O, or the damper 8 Maintenance can be facilitated, and workability is greatly improved. The damper 8 is integrated with the flange pieces 5 to 7 by, for example, vulcanizing the assembly.

  FIG. 6A shows a schematic cross-sectional view of the elastic wheel 1 mounted on the vehicle in a straight traveling state, and FIG. 6B is an enlarged view of the X part thereof. The rim 2 rises relative to the disk 3 due to the reaction force from the road surface. Thereby, the damper 8 receives a shear force between the inward flange piece 5 and the outward flange piece 7 and undergoes shear deformation. The shock and vibration transmitted to the vehicle body are absorbed by the shear deformation of the damper 8 according to the reaction force from the road surface. This action improves riding comfort and reduces noise during traveling. Further, the shear deformation is a deformation that does not substantially change the volume of the damper 8. For this reason, the rubber 8a portion of the damper 8 undergoes the shear deformation without being affected by the cord 8b. Accordingly, the rigidity (that is, the longitudinal rigidity) of the elastic wheel 1 with respect to the load in the vertical direction becomes a small value depending on the elasticity of the rubber 8a.

  Moreover, when the said vertical load becomes large, the outward flange piece 7 will contact the inner peripheral surface 2i of the rim | limb 2, and both relative displacement is controlled. In this case, for example, it is desirable to provide a cushioning material (not shown) that can alleviate the impact at the time of contact on at least one of the outer end portion of the outward flange piece 7 and / or the inner peripheral surface 2i.

  On the other hand, FIG. 7A shows a schematic cross-sectional view of the elastic wheel 1 mounted on a vehicle in a turning state, and FIG. 7B is an enlarged view of the X part thereof. When the lateral force F from the road surface increases, the rim 2 moves relative to the disk 3 in the axial direction. The amount of movement is greatest at a position above the ground plane. At the position, between the inward flange piece 5 and the outward flange piece 7, the damper 8 i inside the turning receives a tensile force and the damper 8 o outside the turning receives a compressive force. The compressive force and tensile force are forces that cause a volume change of the damper 8. However, the rubber 8a inherently does not cause a volume change, and therefore tends to swell or shrink on the unconstrained non-constrained surfaces 8A and 8B. At this time, the cord 8b existing in the rubber 8a suppresses the movement of the rubber 8a, so that the apparent rigidity of the damper 8 is increased. From the above, the lateral rigidity of the damper 8 is relatively increased during turning.

  As described above, the elastic wheel 1 according to the present invention can reduce the vibration and noise level during traveling without significantly deteriorating the steering stability by ensuring the large lateral rigidity while reducing the longitudinal rigidity. .

  The rubber 8a of the damper 8 is not particularly limited. For example, diene such as nitrile rubber (NBR), styrene-butadiene rubber (SBR), butadiene rubber (BR), natural rubber (NR), and isoprene rubber (IR). One type or two or more types of non-diene rubbers such as rubber, butyl rubber (IIR), and ethylene propylene rubber (EPDM) can be used. In particular, from the viewpoint of vibration absorption effect, a rubber composition having a complex elastic modulus E * of 0.5 to 5.0 MPa, more preferably 1.0 to 2.0 MPa is preferable. Further, the loss tangent tan δ of the rubber composition is preferably 0.05 to 0.2, more preferably 0.05 to 0.1 from the viewpoint of durability. The complex elastic modulus E and the loss tangent tan δ are values measured with a viscoelastic spectrometer under conditions of a temperature of 70 ° C., an initial elongation of 10%, a dynamic strain of ± 1.0%, and a frequency of 10 Hz.

  In addition to the nylon cord, the cord 8b includes a cord made of organic fibers such as polyester, rayon, vinylon, aromatic polyamide, cotton, cellulose resin, crystalline polybutadiene, boron, glass fiber, and carbon fiber. One type or two or more types of cords made of inorganic materials such as these are used. An organic fiber cord is preferable. The thickness of the cord 8b is not particularly limited, but if it is too small, there is a tendency that sufficient improvement in lateral rigidity cannot be expected. Conversely, if it is too large, the adhesiveness to the rubber 8a tends to decrease. Preferably, the organic fiber cord is about 800 to 2000 dtex, and the non-organic fiber cord such as steel is preferably about 0.5 to 1.0 mm in outer diameter.

  Moreover, although the damper 8 of this embodiment is shown having a cord 8b extending along the circumferential direction, for example, as shown in FIG. 8A, the damper 8 includes a cord 8b2 extending in the axial direction. But it ’s okay. 8A includes a cord 8b1 extending along the circumferential direction and a cord 8b2 extending along the axial direction. In this example, the cords 8b1 and 8b2 are substantially at an angle of 90 °. Intersect. The cord 8b2 extending along the axial direction exhibits high resistance to the axial compressive force and tensile force generated during turning. For this reason, the lateral rigidity of the damper 8 is further improved, which helps to further improve the steering stability. It is possible to arrange all the cords 8b of the damper 8 along the axial direction.

  In the embodiment of FIG. 8B, the damper 8 includes a cord including cords 8b3 and 8b4 inclined obliquely with respect to the circumferential direction. In particular, in this example, the damper 8 has a cord 8b3 inclined at an angle θ1 of greater than 10 ° and less than 80 ° with respect to the circumferential direction, and a direction opposite to the cord 8b3 and 10 ° with respect to the circumferential direction. And a cord 8b4 inclined at an angle θ2 of greater than 80 °. The cords 8b3 and 8b4 preferably have an intersection angle (θ1 + θ2) greater than 0 and 90 °. The damper 8 including such cords 8b3 and 8b4 has high rigidity in the circumferential direction of the damper 8. Accordingly, when a large torque (torsion) is applied to the damper 8 as in the case of driving or braking of the vehicle, the torsion angle of the damper 8 can be suppressed. Thereby, the response at the time of driving and braking of the vehicle can be improved.

  9A and 9B, the damper 8 includes a cord 8b5 extending in the radial direction (also referred to as radial or the thickness direction of the damper). As shown in FIG. 9A, such a damper 8 is formed by folding a cord ply having cords 8b arranged along the circumferential direction Y while being bent continuously along the radial direction. The cord 8b5 along the radial direction can be formed. Further, as shown in FIG. 5B, the cord 8b5 extending along the radial direction can be formed by overlapping in the circumferential direction Y.

  Further, as shown in FIG. 10, the damper 8 has a plurality of cords 8b arranged along non-restraining surfaces 8A and 8B that are not bonded to the inward flange piece 5 and the outward flange piece 7, and substantially between them. Alternatively, it can be formed of a rubber layer. In this case, the lateral rigidity of the damper 8 can be increased with a small amount of cord by effectively preventing the deformation of the unconstrained surface.

  An elastic wheel having a basic structure shown in FIGS. 1 and 2 (rim size: 7JJ × 16) was prototyped based on the specifications shown in Table 1 and tested for ride comfort, handling stability, and noise performance by running the vehicle. The damper was made by using a cord ply topped with a nylon cord mainly made of natural rubber, and its cross-sectional shape was 10 mm thick and 25 mm wide. As the cord ply, a nylon cord having a diameter of 0.4 mm was driven one per 1 mm of the ply width. In addition, as a conventional example, a normal aluminum wheel of the same size was also tested to compare its performance. The test method is as follows.

<Ride comfort and handling stability>
The tire test course was run under the following conditions, and the ride comfort and steering stability (steering response, turning stability, lane change convergence, grip during driving braking) were evaluated by sensory evaluation of the driver. The result is a 10-point method with 6 points in the conventional example, and the larger the value, the better.
Tire: 225 / 50R16 (empty radial tire)
Internal pressure: 230 kPa
Vehicle: Domestic passenger car, displacement 2000cc (equipped with test wheels on all wheels)
Road surface: dry asphalt road surface

<Noise performance>
The road noise test course was run on the vehicle at a speed of 60 km / h, and the overall noise was measured at the right seat position of the driver's seat, and the frequency analysis was performed.
The test results are shown in Table 1 and FIG.

  As shown in Table 1 and FIG. 11, the elastic wheel of the example improves riding comfort without impairing steering stability, and significantly reduces road noise in a frequency band of 100 Hz or higher. Was confirmed.

It is sectional drawing of the elastic wheel of this embodiment. FIG. It is a perspective view of a damper. It is sectional drawing of a damper. (A), (B) is the side surface schematic explaining the manufacturing method of a damper. (A) is sectional drawing explaining the effect | action of the elastic wheel at the time of straight running, (B) is the X section enlarged view. (A) is sectional drawing explaining the effect | action of the elastic wheel at the time of turning driving | running | working, (B) is the X section enlarged view. (A), (B) is a perspective view which shows other embodiment of a damper. (A), (B) is a perspective view which shows other embodiment of a damper. It is sectional drawing which shows other embodiment of a damper. It is a graph which shows the frequency analysis result of driving noise. It is sectional drawing which shows the conventional elastic wheel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Elastic wheel 2 Rim 3 Disc 4 Connection means 5 Damper 5a, 5b Ring piece 6 Inward flange piece 7 Outward flange piece 8 Damper 8a Rubber 8b Code T Tire D Axle

Claims (6)

An elastic wheel in which a rim on which a tire is mounted and a disk fixed to an axle are elastically connected via a connecting means having a vibration absorbing damper,
The elastic wheel is characterized in that the damper is made of a composite material including rubber and a cord. The connecting means includes at least one inward flange piece projecting radially inward from the inner peripheral surface of the rim and extending in the circumferential direction;
Including at least one outward flange piece provided on an outer peripheral edge of the disk and facing the inward flange piece in the rotational axis direction of the rim and spaced from the inner peripheral surface of the rim;
2. The elastic wheel according to claim 1, wherein the damper has a ring shape that connects between the inward flange piece and the outward flange piece to extend in a circumferential direction. 3.   The elastic wheel according to claim 2, wherein the damper includes a cord extending in a circumferential direction.   The elastic wheel according to claim 2, wherein the damper includes a cord extending in an axial direction.   The elastic wheel according to claim 2, wherein the damper includes a cord extending in a radial direction.   The elastic wheel according to any one of claims 1 to 5, wherein the cord is an organic fiber cord or a steel cord.

Images