JP4826110B2 - Pneumatic radial tire - Google Patents

Description

  The present invention relates to a pneumatic radial tire, and more particularly to a pneumatic radial tire in which a decrease in durability due to heat generation is minimized while maintaining a tire damage prevention function by a protector.

  Vehicles such as light trucks and vans used for delivery of Takkyubin frequently repeat roadside parking, so the tires are often rubbed against the curb, and the rubber in the buttress part wears out early and causes damage Many things are seen.

  Conventionally, in order to prevent damage to the tire as described above, a protector (a raised portion) extending in the tire circumferential direction has been provided in the buttress portion. However, a tire provided with such a protector has a problem in that durability decreases because the amount of heat generation increases as the amount of rubber increases.

Such heat generation can be solved by providing a heat dissipation effect by forming a plurality of narrow grooves extending in the tire circumferential direction on the surface of the annular protector, as disclosed in Patent Document 1, for example. However, when narrow grooves are provided in the tire circumferential direction, there is a problem that stress is concentrated in these narrow grooves and cracks are easily generated.
JP-A-61-81207

  An object of the present invention is to eliminate such conventional problems, and provide a pneumatic radial tire that minimizes a decrease in durability due to heat generation while maintaining a tire damage prevention function by a protector. There is to do.

This onset Ming pneumatic radial tire for achieving the above object, thereby forming a convex protector extending in the tire circumferential direction buttress portion of the radially above range of tire maximum width, the width on the surface of the protector The gist is that narrow grooves extending in the tire circumferential direction of 1 to 5 mm are formed, and a plurality of hemispherical or semi-elliptical spherical depressions having a radius of 1 to 5 mm arranged along the tire circumferential direction are formed on the bottom surface of the narrow grooves. And

According to the present invention, to form a convex protector to buttress portion extending in the tire circumferential direction to form a narrow groove extending in the tire circumferential direction on the surface of this protector, and in the tire circumferential direction on the bottom of the narrow grooves A large number of hemispherical or semi-elliptical spherical depressions are formed along the side, so that the convex protector prevents damage to the tire due to curb rubbing, etc., and the narrow groove formed on the surface of the protector and the bottom surface thereof. A large number of hemispherical or semi-elliptical spherical depressions increase the surface area of the protector, effectively dissipating the heat accumulated in the vicinity of the protector to the outside and minimizing the deterioration of tire durability. it can. Moreover, the generation of cracks can be suppressed by dispersing the stress applied to the fine grooves by a large number of semispherical or semi-elliptical spherical depressions formed on the bottom surface of the fine grooves .

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

FIG. 1 is a half sectional view showing a state in which a pneumatic radial tire according to an embodiment of the present invention is assembled with a rim, and FIG. 2 is a partial perspective view showing a main part of the tire of FIG.

  In FIG. 1, a pneumatic radial tire 1 according to the present invention includes a pair of left and right bead portions 2, side wall portions 3 and buttress portions 4 respectively extending radially outward from these bead portions 2, and these buttresses. The portion 4 includes a cylindrical tread portion T that connects the outsides in the radial direction.

A convex protector 5 extending in the tire circumferential direction is formed in the buttress portion 4 in the radially upper region of the maximum tire width of the pneumatic radial tire 1. And in this invention , as shown in FIG. 2, while forming the narrow groove | channel 8 extended in the tire circumferential direction of width 1-5 mm on the surface of the protector 5, it arranges along the tire circumferential direction on the bottom face of the narrow groove 8. recess of hemispherical or semi-ellipsoidal shape of a number of radial 1~5mm form a (recess 6 of the hemispherical in the figure).

Thereby, the convex protector 5 prevents the tire from being damaged due to curb rubbing or the like, and the fine grooves 8 formed on the surface of the protector 5 and a large number of hemispherical or semi-elliptical spherical depressions formed on the bottom surface thereof (hereinafter, referred to as the following) The hemispherical dent 6) increases the surface area of the protector 5 so that the heat accumulated in the vicinity of the protector 5 can be efficiently dissipated to the outside and the deterioration of the durability of the tire can be suppressed to the minimum. . In addition, the stress applied to the narrow grooves 8 by the hemispherical depressions 6 can be dispersed to suppress the generation of cracks.
Here, if the radius of the hemispherical dent 6 is less than 1 mm, a sufficient heat dissipation effect cannot be obtained, and if it exceeds 5 mm, the rigidity of the protector 5 is lowered, and a damage preventing effect due to curb scuffing cannot be sufficiently obtained. In addition, the radius of the hollow 6 mentioned above shows the radius in the width direction of a semi-elliptical sphere, when the hollow 6 consists of a semi-elliptical spherical form.

  In the present invention, the protrusion height T of the protector 5 from the tire surface is preferably 0.5 to 3.0 mm. If the protrusion height T is less than 0.5 mm, the effect of preventing damage due to curb rubbing or the like cannot be sufficiently obtained.

  Moreover, the protector 5 is good to form in the area | region R corresponded to 15 to 45% of tire cross-section height SH from the tire maximum outer diameter to the inner side of a tire radial direction. If the upper end 5a of the protector 5 is formed so as to be positioned closer to the tire outer peripheral surface side than the region R, the road running performance of curbs will be lowered, and the lower end 5b of the protector 5 will be closer to the bead portion 2 side than the region R. If formed so as to be positioned, the thickness of the side wall portion 3 becomes too large, which is disadvantageous in terms of suppressing heat generation.

In the present invention, a semispherical small depression 7 may be formed on the inner surface of the above-described hemispherical depression 6 as illustrated in FIG. Then, the radius of the small recesses 7 hemispherical in this case, may be set to a radius of 1 / 5-2 / 3 of the recess 6 of the hemispherical. Thereby, the heat dissipation effect in the protector 5 can be further improved.
Furthermore , in this invention, in order to ensure the heat dissipation effect of the protector 5 more reliably, the surface area of the protector 5 is reduced to 20 to 150 by forming the narrow groove 8, the hemispherical depression 6 and the semispherical small depression 7 described above. % Should be increased. If the increase rate of the surface area of the protector 5 is less than 20%, a sufficient heat dissipation effect cannot be obtained, and if it exceeds 150%, the rigidity of the protector 5 is too low and the protector 5 is easily damaged by curb rubbing or the like.

In the pneumatic radial tire 1 of the present invention, as shown in FIG. 4, in addition to the embodiment of FIG. 2, as possible out to form a hemispherical recess 6 with a radius of 1~5mm on the surface of the protector 5. Furthermore, as shown in FIG. 5 , a hemispherical small depression 7 can be formed on the inner surface of the hemispherical depression 6 formed on the bottom surface of the narrow groove 8 .

As described above, in the pneumatic radial tire 1 of the present invention, the convex protector 5 is formed on the buttress portion 4, and the narrow groove 8 extending in the tire circumferential direction is formed on the surface of the protector 5 . By forming hemispherical depressions 6 and hemispherical small depressions 7 in an appropriate combination on the bottom surface, the surface area of the protector 5 is increased to obtain a heat dissipation effect. Therefore, the surface form of the protector 5 in the present invention is not limited to the form illustrated in FIGS .

  In FIG. 1, the right half cross section of the pneumatic radial tire is shown, but the convex protector 5 according to the present invention is formed in the left buttress portion 4 as well as the right buttress portion 4. . However, it is not always necessary to form the convex protector 5 according to the present invention in the left buttress portion 4. And when attaching a pneumatic radial tire to a vehicle, it is good to make the buttress part 4 in which the convex protector 5 was formed located in the outer side of a vehicle.

As described above, the pneumatic radial tire of the present invention forms a convex protector extending in the tire circumferential direction buttress portion located outside of the vehicle at least during vehicle mounted on the surface of this protector in the tire circumferential direction By forming a narrow groove extending and forming a plurality of hemispherical or semi-elliptical spherical recesses arranged along the tire circumferential direction on the bottom surface of the narrow groove, the tire is prevented from being damaged due to curb rubbing, etc. The heat accumulated in the vicinity of the protector is efficiently dissipated to the outside, and it can be widely used for vehicles such as light trucks and van types that require frequent roadside parking.

1 is a half sectional view showing a state in which a pneumatic radial tire according to an embodiment of the present invention is assembled with a rim. It is a partial perspective view which shows the principal part of the tire by embodiment of this invention . FIG. 3 is a perspective view corresponding to FIG. 2 according to another embodiment of the present invention . FIG. 6 is a perspective view corresponding to FIG. 2 according to still another embodiment of the present invention . FIG. 4 is a perspective view corresponding to FIG. 2 according to still another embodiment of the present invention .

Explanation of symbols

l Pneumatic radial tire 2 Bead section 3 Side wall section 4 Buttress section 5 Protector 6 Depression 7 Small depression 8 Narrow groove T Tread section

Claims (7)

  A convex protector extending in the tire circumferential direction is formed in the buttress portion in the radially upper region of the maximum tire width, and a narrow groove extending in the tire circumferential direction having a width of 1 to 5 mm is formed on the surface of the protector. A pneumatic radial tire in which a large number of hemispherical or semi-elliptical spherical depressions having a radius of 1 to 5 mm are arranged on the bottom surface of the tire. The pneumatic radial tire according to claim 1, wherein a height T of the protector protruding from the tire surface is 0.5 to 3.0 mm. The pneumatic radial tire according to claim 1 or 2, wherein the protector is formed in a region corresponding to 15 to 45% of a tire cross-section height SH from a tire maximum outer diameter to an inner side in a tire radial direction. The pneumatic radial tire according to claim 1, 2, or 3, wherein a hemispherical small depression having a radius of 1/5 to 2/3 of a radius of the depression is formed on an inner surface of the depression. The pneumatic radial tire according to any one of claims 1 to 4, wherein a surface area of the protector is increased by 20 to 150% by forming the narrow groove and the depression or the small depression. The pneumatic radial tire according to any one of claims 1 to 5, wherein a hemispherical or semi-elliptical spherical recess having a radius of 1 to 5 mm is formed on a surface of the protector. The pneumatic radial tire according to claim 6, wherein a surface area of the protector is increased by 20 to 150% by forming the semispherical or semielliptical spherical depression.

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