JP2007283779A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire improving rim slippage resistance, while preventing damage from the outside of not only a rim flange but also side wall parts when mounting the tire on a normal wheel having the same left and right flange height, and preventing damage from the outside of the rim flange when mounting the tire on asymmetrical flange wheel having different left and right flange heights. <P>SOLUTION: Rim protecting bars 6a and 6b of two steps swelling to the tire width direction outside are formed at a tire outer wall in a region stretching from a pair of left and right bead parts 3 to the side wall parts 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pneumatic tire. More specifically, when the rim is assembled to a normal wheel having the same left and right flange heights, not only the rim flange but also damage from the outside of the sidewall portion is prevented. The present invention relates to a pneumatic tire in which when a rim is assembled on asymmetric flange wheels having different heights, the rim displacement resistance is improved while preventing damage from the outside of the rim flange.

  In recent years, pneumatic tires for passenger cars or SUVs tend to be flattened due to the need for higher vehicle output and improved steering stability. Such flat tires not only improve tire performance, but also have an effect of enhancing a sporty image when mounted on a wheel, so that needs as one of decorative parts are also increasing. However, an excessive increase in the tire inner diameter accompanying the flattening of the tire has various problems such as an extreme decrease in riding comfort.

  Against this background, in order to obtain a sporty image effect and maintain good riding comfort and running stability, the tire is fitted to an asymmetric flange wheel with the flange height on one side set larger than the standard. The mounting is performed such that the side with the higher flange height is positioned outside the vehicle (see, for example, Patent Document 1).

  This type of tire / rim assembly has a problem that since the outer peripheral end of the rim flange approaches the ground contact surface, the rim flange is easily damaged due to contact with an obstacle during traveling. As a countermeasure, as shown in FIG. 6, by forming an annular bulge portion (rim protect bar) G that protrudes from the outer wall of the tire so as to face the outer peripheral surface of the rim flange 8b on the higher flange height side, There are proposals to prevent damage to the rim flange 8b (see, for example, Patent Documents 2 and 3).

However, in the tire in which the annular rim protect bar G is formed in this way, a part of the load shared by the sidewall portion 2 is directly applied to the annular bulge portion G. There was a problem that the surface pressure between the inner surface and the outer wall of the tire was lowered, and the resistance to rim displacement was lowered.
JP 2004-148904 A JP 2004-359042 A JP 2004-359078 A

  The object of the present invention is to eliminate such a conventional problem. When the left and right flanges are mounted on the same normal wheel, damage from the outside of the sidewall portion as well as the rim flange is prevented. It is an object of the present invention to provide a pneumatic tire that is improved in resistance to rim displacement while preventing damage from the outside of a rim flange when mounted on asymmetric flange wheels having different flange heights.

  In order to achieve the above object, the pneumatic tire of the present invention forms a two-stage rim protect bar that bulges outward in the tire width direction on the tire outer wall in a region extending from the pair of left and right bead portions to the sidewall portion, The gist is that the bulge height of the rim protect bar located on the outer side in the tire radial direction of the two-stage rim protect bar is made larger than the bulge height of the rim protect bar located on the inner side in the tire radial direction.

  In the pneumatic tire of the present invention, the two-stage rim protection bar that bulges outward in the tire width direction is formed on the tire outer wall in the region extending from the pair of left and right bead portions to the sidewall portion. When mounted on a normal wheel with the same flange height, the two-stage rim protect bar effectively prevents damage from the outside of the sidewall during driving, and the left and right flange heights are different. When mounted on the rim, the two-stage rim protection bar prevents damage from the outside of the rim flange, and a large contact area between the tire and the rim flange is ensured on the side where the flange height is high (vehicle outside). Therefore, the surface pressure between the inner surface of the rim flange and the outer wall of the tire is increased, and the rim displacement resistance can be improved.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a sectional view showing an outline of a pneumatic tire according to an embodiment of the present invention, FIG. 2 is a sectional view showing a state where the tire of FIG. 1 is mounted on a normal wheel, and FIG. 3 is an asymmetric flange wheel. It is sectional drawing which shows the mounted state.

  In FIG. 1, 1 is a tread portion, 2 is a sidewall portion, 3 is a bead portion, 4 is a carcass layer, and 5 is a bead filler. The pneumatic tire of the present invention forms two-stage rim protect bars 6a and 6b that bulge outward in the tire width direction on the tire outer wall in a region extending from the pair of left and right bead portions 3 and 3 to the sidewall portions 2 and 2. Of these two-stage rim protect bars 6a and 6b, the bulge height of the rim protect bar 6a located on the outer side in the tire radial direction (hereinafter referred to as upper rim protect bar 6a) is the rim protect located on the inner side in the tire radial direction. It is larger than the bulging height of the bar 6b (hereinafter referred to as the lower rim protect bar 6b).

  The pneumatic tire of the present invention formed in this way is a normal wheel 7 having the same left and right flange heights as shown in FIG. 2, or an asymmetric with different left and right flange heights as shown in FIG. Each is mounted on the flange wheel 8. The tire / wheel assembly shown in FIG. 3 is mounted on the vehicle with the side 8b having the higher flange height as the outside.

  As a result, the two-stage rim protect bars 6a and 6b efficiently prevent the sidewall portion 2 from coming into contact with an external obstacle during traveling, and the height of the left and right flanges is equal to the normal wheel 7. On the other hand, the asymmetrical flange wheel 8 having different left and right flange heights can be freely mounted by selecting a contact position between the flange outer peripheral surface and the rim protect bars 6a and 6b.

  Further, when mounted on the normal wheel 7, the upper rim protect bar 6a exhibits an effect of enhancing the visual image of the tire, and when mounted on the asymmetric flange wheel 8, on the side 8b where the flange height is high. Since a large contact area between the tire and the rim flange is ensured, the surface pressure between the inner surface of the rim flange and the outer wall of the tire is increased, and the rim displacement resistance can be improved.

  The form of the left and right rim protect bars 6a and 6b bulging from the outer wall of the tire is not particularly limited. That is, the left and right rim protect bars 6a and 6b may be formed symmetrically about the tire equatorial plane or may be formed asymmetrical. When the left and right rim protect bars 6a and 6b are formed in an asymmetric shape, the present invention can also be applied to various asymmetric flange wheels having flanges that match the shapes of the rim protect bars 6a and 6b. Therefore, it is advantageous from the aspect of compatibility.

  However, changing the shape of the left and right rim protect bars 6a and 6b is disadvantageous from the viewpoint of tire productivity. Therefore, the left and right rim protect bars 6a and 6b are symmetrical about the tire equatorial plane. It is good to form. Thereby, there is also an advantage that tire replacement (change of the mounting position on the vehicle) when mounting the tire on the asymmetric flange wheel 8 can be freely performed. Further, the inner peripheral surfaces of the rim protect bars 6a and 6b are preferably formed in curved surfaces corresponding to the outer peripheral surfaces of the rim flanges in order to improve the mounting property with the wheel.

  Furthermore, the wall surface y in the tire radial direction outer side region of the lower rim protect bar 6b may be formed so as to be inclined outward in the tire width direction from the inner side in the tire radial direction to the outer side. Thereby, while improving the fitting property at the time of fitting a pneumatic tire to the asymmetric flange wheel 8, it is possible to form the flange thickness in the asymmetric flange wheel 8 so as to gradually decrease toward the outer side in the tire radial direction. The durability of the tire / wheel assembly can be increased.

  Moreover, it is good to form the unevenness | corrugation (not shown) extended in a tire radial direction in the contact surface with the rim flange of the rim protect bars 6a and 6b. Thereby, the rim | limb assembly property at the time of fitting a pneumatic tire to the flange wheels 7 and 8 can be improved. The unevenness described above needs to be formed so that the uneven state is eliminated by the fitting pressure between the tire and the flange wheels 7 and 8 so that the tire filling internal pressure does not leak after the rim assembly is completed. There is.

  As described above, when the pneumatic tire of the present invention is mounted on the asymmetric flange wheel 8 having different left and right flange heights, the lower rim protect bar 6b comes into contact with the outer peripheral surface of the rim flange on the side 8a having the lower flange height. The upper rim protect bar 6a comes into contact with the outer peripheral surface of the rim flange on the side 8b having the higher flange height. In addition, the outer peripheral surface of the asymmetric flange wheel 8 is formed on the step surface corresponding to the upper rim protect bar 6a and the lower rim protect bar 6b on the side 8b having a higher flange height.

  Thus, a large contact area between the tire and the rim is ensured on the side 8b where the flange height is high, and the inner peripheral surface of the upper rim protect bar 6a and the inner peripheral surface of the lower rim protect bar 6b are respectively Since it is supported by the stepped outer peripheral surface of the opposing asymmetric flange wheel 8, the load sharing for the sidewall portion 2 is distributed and applied to these two-stage rim protect bars 6 a, 6 b. The surface pressure between the outer wall of the tire increases and the rim displacement resistance can be improved.

  When the pneumatic tire of the present invention is mounted on the asymmetric flange wheel 8, on the side 8b having a high flange height, the inner diameter H1 of the lower rim protect bar 6b corresponds to the rim protect bar 6b as shown in FIG. It is good to adjust so that it may become 0 to 0.5% smaller than the outer diameter H2 of the rim flange on the side 8b where the flange height is high. As a result, the contact pressure between the inner peripheral surface of the rim protect bar 6b and the corresponding outer peripheral surface of the rim flange is secured, and the rim displacement resistance is reliably improved without impairing the rim assembling property. Can do.

  As shown in FIG. 5, on the side 8a having a low flange height, the inner diameter H3 of the lower rim protect bar 6b is set to the outside of the rim flange on the side 8a having a low flange height, as in the rim protect bar in a normal tire. It is formed to be larger than the diameter H4 by several mm, preferably by about 3 to 12 mm.

  In order to make the tire size common with 245 / 45R18 and to be mounted on the asymmetric flange wheel, the shape of the tire outer wall in the region extending from the beat portion located outside the vehicle to the sidewall portion is made different. A tire / wheel assembly (conventional example) having the form shown in FIG. 3 and a tire / wheel assembly (example) having the form shown in FIG. As the rim in the asymmetric flange wheel, an asymmetric rim in which the flange height on one side of a rim of size 18 × 8J was increased by 2 inches was used. Further, the tire filling internal pressure in each assembly was set to 230 kPa.

These two types of assemblies are mounted on the front and rear wheels of the vehicle (3000cc, FR vehicle), respectively, and the test course consisting of asphalt road surface starts suddenly (0 → 50km / h) and suddenly brakes (50 → 0km / h) Was repeated 20 times, and the amount of deviation in the circumferential direction between the tire and the rim after running was measured. The results are shown in Table 1.

  From Table 1, it can be seen that the rim displacement resistance of the assembly (Example) shown in FIG. 3 is drastically improved as compared with the assembly (conventional example) shown in FIG.

It is sectional drawing which shows the outline | summary of the pneumatic tire by embodiment of this invention. It is sectional drawing which shows the state which mounted | wore the normal wheel with the tire of FIG. It is sectional drawing which shows the state which mounted | wore the asymmetrical flange wheel with the tire of FIG. FIG. 4 is a partial cross-sectional view illustrating a mounting state on the side having a higher flange height in the tire / wheel assembly of FIG. 3. FIG. 4 is a partial cross-sectional view illustrating a mounting state on the side having a lower flange height in the tire / wheel assembly of FIG. 3. It is sectional drawing which shows the state with which the conventional pneumatic tire was mounted | worn with the asymmetrical flange wheel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Carcass layer 5 Bead filler 6a, 6b Rim protect bar 7 Normal wheel 8 Asymmetric flange wheel 8a Flange height side 8b Flange height side

Claims (6)

  A two-stage rim protect bar bulging outward in the tire width direction is formed on the tire outer wall in a region extending from the pair of left and right bead portions to the sidewall portion, and the two-stage rim protect bar is positioned on the outer side in the tire radial direction. A pneumatic tire in which the bulge height of the rim protect bar is larger than the bulge height of the rim protect bar located inside the tire in the radial direction.   The pneumatic tire according to claim 1, wherein the two-stage rim protect bar is formed symmetrically about the tire equator plane.   The pneumatic tire according to claim 1 or 2, wherein a wall surface of an outer region in the tire radial direction of the rim protect bar located on the inner side in the tire radial direction is inclined outward in the tire width direction from the inner side in the tire radial direction to the outer side.   The pneumatic tire according to claim 1, wherein unevenness extending in a tire radial direction is formed on a contact surface of the rim protect bar with a rim flange.   When mounted on asymmetric flange wheels with different left and right flange heights, the rim protect bar located on the inner side in the tire radial direction comes into contact with the outer peripheral surface of the rim flange on the lower flange height side, and the rim on the higher flange height side The pneumatic tire according to any one of claims 1 to 4, wherein a rim protect bar located on the outer side in the tire radial direction is in contact with a flange outer peripheral surface. On the higher flange height side, the inner diameter H1 of the rim protect bar located on the inner side in the tire radial direction is 0 to 0 than the outer diameter H2 of the rim flange on the higher flange height side corresponding to the rim protect bar. The pneumatic tire according to claim 5, wherein the pneumatic tire is 5% smaller.

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