JPH0672105A - Pneumatic tire for construction vehicle - Google Patents

Abstract

PURPOSE:To improve durability against rubbing of a metal chain attached for use while preventing traction from deficiency when the chain is not attached. CONSTITUTION:A lug pattern block 16 of a pneumatic tire 10 for a construction vehicle is discontinuously divided by lug grooves 14 extending in the nearly diametral direction of the tire. The lug groove 14 is provided in the outer edge end portion 14B in the width direction of the tire of a groove bottom 14A with groove bottom projection 18, and a lug pattern block 16 is provided in the outside edge 16A of the lug pattern block 16 in the width direction of the tire with a block projection 20. The diametral position of the tire on the upper end 18A of the groove bottom projection 18 coincides with the diametral position of tire of the upper end 20A of the block projection 20, and the lower end 18B of the groove bottom projection 18 coincides with the lower end 20B of the block projection 20. Thus, the groove bottom projection 18 and the block projection 20 are formed substantially contiguously to each other in the circumferential direction of the tire.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire for a construction vehicle, and more particularly to a pneumatic tire for a construction vehicle which is provided with a lug groove on a tread and a buttress portion and is used even when a metal chain is attached.

[0002]

2. Description of the Related Art Conventionally, in pneumatic tires for construction vehicles, since the tire travels on rough terrain such as a construction site, a portion of the sidewall of the tire near the outermost radial position of the tire in the radial direction is cut by rocks or the like. Easy to receive. Further, since the cutting of this portion is performed by a side cut by a sharp stone when the tire is stepped on or by stepping on a rolling rock, the cutting direction is mainly the tire radial direction.
Further, the rubber on the outer surface of this portion is likely to be broken due to a large circumferential strain when the tire rolls. When a rock or the like hits the rubber, the rubber is likely to be cut and the depth of the cut is increased.

Examples of tires that have improved this problem and have improved sidewall cut resistance include, for example, the actual open tire shokai 62.
There is known one such as described in the specification of No. 111205.

As shown in FIG. 4, in the pneumatic tire 70 for a construction vehicle, a convex side protector 74 is annularly arranged at a portion of the sidewall 72 near the tire maximum width position M in the radial direction. Has been done. The tire radial direction distance L1 between the upper end 74A of the side protector 74 and the widthwise center P of the tire tread is 10 to 20% of the tire cross-section height SH.
The distance L2 in the tire radial direction between the lower end 74B of No. 4 and the widthwise center P of the tire tread is 25 to 4 of the tire cross-section height SH.
It is 0%. Furthermore, the thickness M of the side protector 74
Is 1.5% or more of the maximum tire width SW. Therefore, even if a side cut is received, the scratches can be prevented from reaching the carcass, and the sidewall cut resistance can be improved.

However, since the side protector 74 of the pneumatic tire 70 for a construction vehicle is for improving the sidewall cut resistance, the groove bottom portion 76A of the lug groove 76 shown by the imaginary line in FIG. Not formed. Therefore, when a metal chain for traveling on a snowy road is mounted, the rubber gauge is thin especially at the groove bottom portion 76A among the parts that the metal chain abuts, so that scratches easily reach the carcass due to scratches of the metal chain and the scratch durability is low. .

[0006]

SUMMARY OF THE INVENTION In consideration of the above facts, the present invention provides a pneumatic tire for a construction vehicle, which is capable of improving abrasion resistance by the metal chain when the metal chain is mounted and used. With the goal.

[0007]

The present invention according to claim 1 provides a pneumatic tire for a construction vehicle having a lug pattern block in which a tread portion is discontinuously divided by a lug groove extending in a tire radial direction, A groove bottom projection provided on the tire width direction outer edge end portion of the groove bottom portion of the lug groove, and a block projection provided on the tire width direction outer edge portion of the lug pattern block, the groove bottom projection of The tire radial positions of the upper end portion and the upper end portion of the block protrusion are equal to each other, and the lower end portion of the groove bottom protrusion and the tire radial position of the lower end portion of the block protrusion are the same, and the groove bottom protrusion and the block protrusion are the tire circumference. It is characterized in that it is formed substantially continuously in the direction.

The present invention according to claim 2 provides the invention according to claim 1.
In the invention described above, the thickness of the groove bottom protrusion and the thickness of the block protrusion are uniform and equal, and the tire maximum width is 0.4
The thickness in the tire radial direction between the upper ends of the groove bottom protrusions and the block protrusions and the widthwise center of the tire tread is 20% of the tire cross-sectional height. The distance in the tire radial direction between the lower end portion of the groove bottom protrusion and the lower end portion of the block protrusion and the center in the width direction of the tire tread is 40% or more of the tire cross-section height at 30% or less.
It is characterized in that it is set to be 50% or more and 50% or less.

[0009]

According to the first aspect of the present invention, the tire radial direction positions of the tire width direction outer edge end portion of the tire lug groove bottom portion and the tire width direction outer edge portion of the lug pattern block are the tire radial direction positions. Since the groove bottom projections and block projections, which are equal to each other and whose lower end portions are the same, are substantially continuous in the tire circumferential direction, are provided, the carcass is likely to be damaged by the chain rubbing when the chain is attached. Is thicker, and the abrasion resistance of the metal chain can be improved.

In addition, the outer edge portion of the groove bottom portion in the tire width direction is thickened, and the outer edge portion of the lug pattern block in the tire width direction is also thickened, and the upper end portion of the groove bottom projection and the upper end portion of the block projection are also thickened. The tire radial direction positions are made equal to each other, and the lower end portions of the groove bottom protrusions and the block protrusions are made equal in tire radial direction position so that the groove bottom protrusions and the block protrusions are substantially continuous in the tire circumferential direction. Therefore, the groove depth at the outer edge portion of the groove bottom portion in the tire width direction becomes substantially equal to the case where the groove bottom projection and the block projection are not provided, and the traction performance when the chain is not attached does not deteriorate. .

The thickness of the groove bottom protrusion and the thickness of the block protrusion are uniform and equal, and the thickness is preferably 0.4 to 1.0% of the maximum tire width. This is because when the tire maximum width is less than 0.4, the effect of improving scratch resistance is small, and when the tire maximum width is greater than 1.0, traction is insufficient.

Further, the distance in the tire radial direction between the upper ends of the groove bottom projections and the block projections and the widthwise center of the tire tread is 20% or more and 30% or more of the tire cross-section height.
The following is preferable. This is the tire cross-section height of 2
If it is less than 0%, the entire rubbing range by the metal chain cannot be covered and the effect of improving the rubbing durability is small, and if it is more than 30% of the tire cross-section height, sufficient traction performance in snow and soft ground when the tire is used alone Can't get

Further, the distance in the tire radial direction between the lower end of the groove bottom protrusion and the lower end of the block protrusion and the widthwise center of the tire tread is 40% or more and 50% or more of the tire cross-sectional height, respectively.
The following is preferable. This is the tire cross-section height of 4
If it is less than 0%, the entire rubbing range of the metal chain cannot be covered, and the effect of improving the rubbing durability is small, and if it is more than 50% of the tire cross-section height, the flex zone becomes extremely narrow, resulting in steering stability and riding comfort. Is not preferable because it causes a decrease in

[0014]

EXAMPLE An example of a pneumatic tire for a construction vehicle according to the present invention will be described with reference to FIG.

As shown in FIG. 1, a lug pattern block 16 is formed on the tread surface of a tread 12 of a pneumatic tire 10 (tire size: 14.00-24) for construction vehicles.

As shown in FIG. 3, the lug pattern block 16 of the pneumatic tire 10 for a construction vehicle is discontinuously divided by a lug groove 14 extending substantially in the tire radial direction.

As shown in FIG. 2, the groove bottom projection 1 is formed on the tire width direction outer edge portion 14B of the groove bottom portion 14A of the lug groove 14.
8 is formed, and a block protrusion 20 is formed on the tire width direction outer edge portion 16A of the lug pattern block 16.

The tire radial position of the upper end portion 18A of the groove bottom protrusion 18 (the vertical position in FIG. 2) and the tire radial direction position of the upper end portion 20A of the block protrusion 20 (the vertical position in FIG. 2).
Are equal to each other, and the lower end portion 18B of the groove bottom protrusion 18 and the lower end portion 20B of the block protrusion 20 coincide with each other. Therefore, the groove bottom protrusion 18 and the block protrusion 20 are formed substantially continuously in the tire circumferential direction.

The thickness T1 of the groove bottom protrusion 18 and the thickness T2 of the block protrusion 20 are uniform and equal, and the tire maximum width SW is
It is formed with a thickness of 0.4 to 1.0% (see FIG. 1).

As shown in FIG. 1, the radial distance H1 between the upper end 18A of the groove bottom projection 18 and the upper end 20A of the block projection 20 and the widthwise center P of the tire tread surface.
Is 20% or more and 30% or less of the tire cross-section height SH, and the tire radius between the lower end portion 18B of the groove bottom protrusion 18 and the lower end portion 20B of the block protrusion 20 and the widthwise center P of the tire tread surface. The direction distance H2 is set to 40% or more and 50% or less of the tire cross-section height SH, respectively. In FIG. 1, reference numeral TW indicates the tread width.

Next, the operation of this embodiment will be described. In the pneumatic tire 10 for a construction vehicle of the present embodiment, the tire width direction outer edge end portion 14B of the groove bottom portion 14A of the lug groove 14 and the tire width direction outer edge portion 16A of the lug pattern block 16 have upper end portions 18A, 20A and The lower end portions 18B, 20B have the same tire radial position, and the lower end portions 18B, 20B
Since the groove bottom projections 18 and the block projections 20 are provided so as to coincide with each other in the tire circumferential direction and are substantially continuous in the tire circumferential direction, the carcass is apt to be damaged by abrasion by the chain when the chain is mounted, and the outer edge portion 14B of the groove bottom portion 14A in the tire width direction. Is thicker, and the abrasion resistance of the metal chain can be improved.

Further, the tire width direction outer edge portion 14B of the groove bottom portion 14B is made thick, and the tire width direction outer edge portion 16A of the lug pattern block 16 is also made thick, and
The upper end portion 18A of the groove bottom protrusion 18 and the upper end portion 20A of the block protrusion 20 are located at the same position in the tire radial direction, and the lower end portion 18B of the groove bottom protrusion 18 and the block protrusion 20 are arranged.
Since the groove bottom protrusions 18 and the block protrusions 20 are substantially continuous in the tire circumferential direction, the lower end portions 20B of the tires are arranged at the same position in the tire radial direction. The depth is substantially equal to that when the groove bottom projection and the block projection are not provided, and the traction performance when the chain is not attached does not deteriorate.

The thickness T1 of the groove bottom protrusion 18 and the thickness T2 of the block protrusion 20 are uniform and equal, and the tire maximum width SW is
The thickness is preferably 0.4 to 1.0%. This is because when the tire maximum width SW is less than 0.4, the effect of improving scratch resistance is small, and the tire maximum width SW is 1.
This is because if the thickness is greater than 0, the traction will be insufficient.

The distance H1 in the tire radial direction between the upper end portion 18A of the groove bottom projection 18 and the upper end portion 20A of the block projection 20 and the widthwise center P of the tire tread is 20% or more of the tire cross-section height SH. % Or less is preferable. This is because if the tire cross-section height SH is less than 20%, the entire rubbing range of the metal chain cannot be covered and the effect of improving the rubbing durability is small, and the tire cross-section height SH is 30%.
This is because if it is larger than the above range, sufficient traction performance cannot be obtained in snow and soft ground when the tire is used alone.

The distance H2 in the tire radial direction between the lower end portion 18B of the groove bottom protrusion 18 and the lower end portion 20B of the block protrusion 20 and the widthwise center P of the tire tread is 40% or more of the tire cross-section height SH. % Or less is preferable. This is because if the tire cross-section height SH is less than 40%, the entire rubbing range of the metal chain cannot be covered and the effect of improving the rubbing durability is small, and the tire cross-section height SH is 50%.
This is because if it is larger than the above range, the flex zone becomes extremely narrow, resulting in deterioration of steering stability and riding comfort.

(Test Example 1) Pneumatic tires for construction vehicles of the present embodiment shown in FIG. 1, pneumatic tires for construction vehicles of Comparative Examples 1 to 5 and conventional tires having no protrusions. The specifications in Table 1 (the size of each tire is 14.00-2
The tire was prototyped in 4), and each tire was subjected to a chain abrasion durability test, a traction test, and a tire weight measurement by the following methods.

In the chain rubbing durability test, a metal chain is attached to each tire, an actual vehicle durability test is performed, and the time until the rubbing by the chain reaches the carcass is measured, and the result is used for a pneumatic tire for a construction vehicle having a conventional structure. It is shown in Table 1 as an index when 100 is set. It is assumed that the larger the index, the better.

In the traction test, the maximum value of static traction in muddy ground was measured as traction, and the result is shown in Table 1 as an index when the pneumatic tire for a construction vehicle having a conventional structure is 100. . It is assumed that the larger the index, the better.

The tire weight is shown in Table 1 as an index when the pneumatic tire for a construction vehicle having a conventional structure is 100. The smaller the index, the better.

[0030]

[Table 1]

From the results shown in Table 1, it was revealed that the pneumatic tire for construction vehicles of this example is excellent.

[0032]

EFFECTS OF THE INVENTION Since the present invention has the above-mentioned structure, it is possible to improve the abrasion resistance of the metal chain when the metal chain is mounted and used, and the traction may be insufficient when the chain is not mounted. It has an excellent effect that it does not exist.

[Brief description of drawings]

FIG. 1 is a schematic half sectional view showing a pneumatic tire for a construction vehicle according to an embodiment of the present invention.

FIG. 2 is a schematic half sectional view showing a groove bottom protrusion and a block protrusion of a pneumatic tire for a construction vehicle according to an embodiment of the present invention.

FIG. 3 is a plan view showing a lug pattern of a pneumatic tire for a construction vehicle according to an embodiment of the present invention.

FIG. 4 is a schematic half sectional view showing a pneumatic tire for a construction vehicle according to a conventional example.

[Explanation of symbols]

 10 Pneumatic Tire for Construction Vehicles 12 Tread 14 Lug Groove 14A Groove Bottom 14B Tire Width Outside Edge 16 Lug Pattern Block 16A Tire Width Outside Edge 18 Groove Bottom Protrusion 18A Top End 18B Bottom End 20 Block Protrusion 20A Top End 20B Bottom edge

Claims (2)

[Claims] 1. A pneumatic tire for a construction vehicle having a lug pattern block in which a tread portion is discontinuously divided by a lug groove extending in a tire radial direction, in a tire width direction outer edge portion of a groove bottom portion of the lug groove. And a block protrusion provided on an outer edge portion in the tire width direction of the lug pattern block, the tire radial direction position of the upper end of the groove bottom protrusion and the upper end of the block protrusion. Are equal to each other, and the lower end portions of the groove bottom projections and the lower end portions of the block projections are aligned in the tire radial direction, and the groove bottom projections and the block projections are formed substantially continuously in the tire circumferential direction. A characteristic pneumatic tire for construction vehicles. 2. The thickness of the groove bottom protrusion and the thickness of the block protrusion are uniform and equal, and the maximum tire width of 0.4 to 1.
The tire radial direction distance between the upper end of the groove bottom protrusion and the upper end of the block protrusion and the center of the tire tread in the width direction is 20% of the tire sectional height.
% Or more and 30% or less, the tire radial direction distance between the lower end of the groove bottom protrusion and the lower end of the block protrusion and the widthwise center of the tire tread is set to 40% or more and 50% or less of the tire cross-sectional height, respectively. A pneumatic tire for a construction vehicle, which is characterized by being