JP2006027353A - Pneumatic tire for off-road - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire for off-road for improving cut-resistance while preventing increases of noises and tire mass. <P>SOLUTION: This pneumatic tire 10 for off-road has a carcass layer 22 as a frame of the pneumatic tire 10 for off-road; a tread part 21 arranged outside the carcass layer 22 in a tire radial direction; and a cord reinforcing layer 30 constituted by impregnating a three-axis woven fabric 30A obtained by weaving cords arranged outside in a tire peripheral direction and a tire radial direction of the carcass layer 22 and arranged along three axial directions crossing with one another at any of a side wall part 27 or a tread shoulder part 28 with a rubber component. Cords (30X, 30Y, 30Z) constituting the three-axis woven fabric 30A are formed of at least one of predetermined organic fiber, predetermined inorganic fiber, or predetermined metallic fiber. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an off-road pneumatic tire having a triaxial fabric that reinforces a carcass layer.

  In recent years, the number of vehicles called recreational beagles (hereinafter referred to as RVs) has increased rapidly due to outdoor orientation, family orientation, and user preferences such as riding in a different car.

  The RV is fitted with off-road pneumatic tires (including SUV (sports utility beagle) pneumatic tires) capable of traveling on rough roads and off-roads. When the tire comes into contact with rocks or rubble from the sidewall of the off-road pneumatic tire to the tread shoulder on a rough road, the carcass layer breaks and the air leaks due to the carcass layer breaking. Will occur.

Therefore, conventionally, as a means for improving the cut resistance of off-road pneumatic tires, when the vehicle is viewed from the front, the angle of the contact surface between the tire and the ground (the angle on the outside of the vehicle) is larger than before. To prevent the tire from coming into contact with rocks and debris, to thicken the rubber in the sidewall to prevent the carcass layer from breaking, and to an organic fiber canvas that can be stretched to a predetermined location in the sidewall A method of improving the strength of the sidewall portion by providing a nylon knitted fabric is known (for example, Patent Document 1).
Japanese Patent Laid-Open No. 6-199144 (page 1-2, FIG. 1)

  However, in the above-mentioned method in which the angle of the contact surface between the tire and the ground is made larger than before and the tire is prevented from coming into contact with rocks and rubble, the maximum width of the tire (maximum width of the sidewall) is EC standard. Therefore, as the angle of the contact surface between the tire and the ground is increased, it is necessary to increase the tread width, and there is a problem that the noise and the mass of the tire increase.

  Further, the method of preventing the carcass layer from being broken by thickening the rubber in the sidewall portion has a problem that the tire mass increases due to the thick rubber in the sidewall portion.

  In addition, in the method of improving the strength of the sidewall portion by providing a stretchable nylon knitted fabric at a predetermined portion of the sidewall portion, the cut resistance is improved by the nylon knitted fabric, but the cut resistance is further increased. There was a need to improve.

  Therefore, the present invention has been made in view of such a problem, and an object thereof is to provide an off-road pneumatic tire that prevents noise and increase in tire mass and further improves cut resistance. To do.

  Based on the above-described problems, the inventors have analyzed noise, an increase in tire mass, and cut resistance. As a result, by providing a cord reinforcing layer formed by impregnating a triaxial fabric with a rubber component from a sidewall portion to a tread shoulder portion of the off-road pneumatic tire, the off-road pneumatic tire It has been found that cut resistance is improved while preventing an increase in the weight of tires and tires.

  Therefore, the present invention has the following features. First, the first feature of the present invention is that a carcass layer (carcass layer 22) serving as a skeleton of an off-road pneumatic tire, a tread portion (tread portion 21) disposed on the outer side in the tire radial direction of the carcass layer, Arranged along the three axial directions that are arranged on the tire circumferential direction and on the outer side in the tire radial direction of the carcass layer in either the sidewall portion (sidewall portion 27) or the tread shoulder portion (tread shoulder portion 28). A cord reinforcing layer (cord reinforcing layer 30) configured by impregnating a rubber component into a triaxial woven fabric (triaxial woven fabric 30A) obtained by weaving cords (for example, cord 30X to cord 30Z) The pneumatic tire (pneumatic tire 10) has a cord that constitutes the triaxial woven fabric, a predetermined organic fiber, a predetermined inorganic fiber Or, the gist that it is formed of at least one of the predetermined metal fibers.

  According to such a feature, the cord reinforcing layer constituted by impregnating a rubber component into a triaxial woven fabric using a predetermined organic fiber, a predetermined inorganic fiber, or a predetermined metal fiber is formed on the tread from the sidewall portion. Since it arrange | positions in a tire circumferential direction over a shoulder part, while preventing the increase in a noise and the mass of a tire, cut resistance can be improved.

  A second feature of the present invention relates to the first feature of the present invention, wherein the first axis (X axis) of the triaxial fabric is arranged along the tire circumferential direction, and the second feature of the triaxial fabric is the second feature. The gist is that the axis (Y-axis) and the third axis (Z-axis) are arranged at an angle of 60 ° or less with respect to the first axis.

  According to this feature, since the stiffness distribution is oriented in the tire circumferential direction, the impact when rocks and rubble contact with the tire is dispersed, so that the cut resistance can be further improved.

  A third feature of the present invention relates to the first feature or the second feature of the present invention, wherein the predetermined organic fiber is an aromatic polyamide fiber, a fatty acid polyamide fiber, a polyester fiber, a polyparaphenylenebenzeneoxazole fiber, or polyvinyl alcohol. It is summarized as a synthetic fiber or carbon fiber.

  A fourth feature of the present invention relates to the first feature or the second feature of the present invention, and is summarized in that the predetermined inorganic fiber is a glass fiber.

  A fifth feature of the present invention relates to the first feature or the second feature of the present invention, and is summarized in that the predetermined metal fiber is a steel wire.

  According to such characteristics, predetermined organic fibers (the organic fibers are aromatic polyamide fibers, fatty acid polyamide fibers, polyester fibers, polyparaphenylenebenzeneoxazole fibers, polyvinyl alcohol-based synthetic fibers or carbon fibers), predetermined inorganic fibers (glass fibers) ) Or a predetermined metal fiber (steel wire) is used for the triaxial woven fabric, the cut resistance can be improved more effectively.

  ADVANTAGE OF THE INVENTION According to this invention, while preventing the increase in a noise and the mass of a tire, the off-road pneumatic tire which improved the cut resistance further can be provided.

(Configuration of off-road pneumatic tire)
Next, an example of an off-road pneumatic tire according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  FIG. 1 is a partially exploded perspective view of an off-road pneumatic tire 10 according to the present embodiment. As shown in FIG. 1, the off-road pneumatic tire 10 has a pair of bead portions 23 including a bead core 23a and a bead filler 23b that come into contact with a rim portion (not shown) of the wheel. Specifically, an aramid fiber cord (such as Kevlar) or a steel cord is used for the bead core 23a constituting the bead portion 23.

  The off-road pneumatic tire 10 has a carcass layer 22 that is a skeleton of the off-road pneumatic tire 10. A first belt layer 24a (inner belt layer) and a second belt layer 24b (outer belt layer) are disposed on the outer side of the carcass layer 22 in the tire radial direction.

  A tread portion 21 that contacts the road surface is disposed on the outer side in the tire radial direction of the first belt layer 24a and the second belt layer 24b. Further, the sidewall portion 27 or the tread shoulder portion 28 is impregnated with a rubber component in a triaxial fabric 30A (not shown in FIG. 1) in which cords arranged along three mutually intersecting axial directions are woven together. The cord reinforcing layer 30 formed by this is disposed in the tire circumferential direction and on the outer side in the tire radial direction of the carcass layer 22.

  Next, with reference to FIG. 2, the position where the above-described cord reinforcing layer 30 is disposed will be briefly described. FIG. 2 is a cross-sectional view of the off-road pneumatic tire 10 in the tire width direction and the tread width direction.

  As shown in FIG. 2, the cord reinforcing layer 30 is disposed from the sidewall portion 27 to the tread shoulder portion 28. The cord reinforcing layer 30 is disposed on the outer side in the tire radial direction of the carcass layer 22. The cord reinforcing layer 30 is preferably provided between the carcass layer 22 and the side tread 25 in the molding step.

  Next, with reference to FIG. 3, the triaxial fabric 30A constituting the cord reinforcing layer 30 will be briefly described. FIG. 3 is an enlarged plan view of the cord reinforcing layer 30 in the off-road pneumatic tire 10.

  As shown in FIG. 3, the triaxial fabric 30A constituting the cord reinforcing layer 30 includes a cord 30X and a Y axis (second axis) arranged along the X axis (first axis) in the same plane. ) And the cord 30Z arranged along the Z axis (third axis) are interwoven together. Each cord (30X, 30Y, and 30Z) crosses one after another at the crossing portion in the vertical direction and alternately.

  Here, it is preferable that the Y axis and the Z axis are configured to form an angle of 60 ° or less with respect to the X axis. Moreover, it is preferable that the cord reinforcement layer 30 is disposed so that the X-axis is along the tire circumferential direction.

  In addition, as a material of each cord (30X, 30Y, and 30Z), a predetermined organic fiber, a predetermined inorganic fiber, or a predetermined metal fiber is used, or a material obtained by weaving them may be used.

  In addition, the predetermined organic fiber is preferably an aromatic polyamide fiber, a fatty acid polyamide fiber, a polyester fiber, a polyparaphenylenebenzeneoxazole fiber, a polyvinyl alcohol-based synthetic fiber, or a carbon fiber, but is not limited thereto. For example, the strength of the organic fiber may be 120 N / fiber or more.

  Moreover, it is preferable that a predetermined inorganic fiber is a glass fiber, It is not limited to this. For example, the inorganic fiber may be an inorganic fiber having a strength of 300 N / fiber or more.

  Further, the predetermined metal fiber is preferably a steel wire, but is not limited thereto. For example, the strength of the metal fiber may be 500 N / fiber or more.

  The triaxial woven fabric 30A configured in this manner has a rigidity distribution in the tire circumferential direction, so that the impact when rocks and rubble come into contact with the tire is dispersed, so that the cut resistance can be further improved. .

  Next, in order to further clarify the effects of the present invention, the results of tests performed using off-road pneumatic tires according to the following comparative examples and examples will be described.

  The sizes of the off-road pneumatic tires used in Comparative Examples 0 to 3 and the examples are both “265 / 70R16”. That is, the cross-sectional width (tire width) is about 265 mm, the flatness (ratio of the tire cross-sectional height to the tire width) is about 70%, and the rim diameter is 16 inches.

  Table 1 shows the relationship between the carcass layer, TA (Tread Angle) index, side Ga (Gauge), and side reinforcement of the pneumatic tire for off-road according to Comparative Examples 0 to 3 and Examples.

The TA index is obtained by indexing the angle of the contact surface between the tire and the ground (the angle outside the vehicle). Further, the TA index indicates that the off-road pneumatic tire according to Comparative Example 0 described later is “100”, and when it is less than “100”, the angle of the contact surface between the tire and the ground is small. Side Ga indicates the thickness of the rubber in the side wall portion.

  As shown in Table 1, the pneumatic tire for off-road according to Comparative Example 0 is a tire that serves as a reference for the pneumatic tires according to Comparative Examples 1 to 3 and Examples described later. The off-road pneumatic tire according to Comparative Example 0 has a carcass layer of “2PHTU”, a TA index of “100”, a side Ga of “4 mm”, and no side reinforcement.

  Further, the off-road pneumatic tire according to Comparative Example 1 has a larger contact angle between the tire and the ground (the angle on the vehicle outer side) than the conventional tire when the vehicle is viewed from the front. TA-up tires that avoid rocks and rubble. The off-road pneumatic tire according to Comparative Example 1 has a carcass layer of “2PHTU”, a TA index of “105”, a side Ga of “4 mm”, and no side reinforcement.

  Note that 2PHTU indicates a high turn-up structure (HTU) in which the number of carcass layers (so-called ply) is 2 plies (P) and the folded portion of the carcass layer is long.

  The off-road pneumatic tire according to Comparative Example 2 is a side Ga-up tire that thickens the rubber in the sidewall portion to prevent the carcass layer from being broken. The off-road pneumatic tire according to Comparative Example 2 has a carcass layer of “2PHTU”, a TA index of “100”, a side Ga of “4 mm”, and no side reinforcement.

  Further, the off-road pneumatic tire according to Comparative Example 3 is a tire with a nylon knitted fabric that is provided with a stretchable nylon knitted fabric at a predetermined portion of the sidewall portion to improve the strength of the sidewall portion. In the off-road pneumatic tire according to Comparative Example 3, the carcass layer is “2PHTU”, the TA index is “100”, the side Ga is “3 mm”, and the side reinforcement is a nylon knitted fabric. .

  Further, the off-road pneumatic tire according to the example is a tire with a cord reinforcing layer 30 configured by impregnating a triaxial fabric 30A using a metal fiber (steel wire) with a rubber component. In the pneumatic tire for off-road according to this example, the carcass layer is “2PHTU”, the TA index is “100”, the side Ga is “3 mm”, and the side reinforcement is the cord reinforcement layer 30 (triaxial). Woven fabric 30A).

Next, Table 2 shows the relationship between cut resistance, tire mass, and noise in Comparative Examples 1 to 3 and Examples.

  As shown in Table 2, the cut resistance test, the tire mass test, and the noise test were performed as follows for the above-described comparative example 0 to comparative example 3 and the off-road pneumatic tire according to the example.

<Cut resistance test>
The cut depth and cut of the off-road pneumatic tire according to Comparative Example 0 when the above-mentioned off-road pneumatic tires are assembled on a standard rim (7JJ × 16) and run on a rough road for a certain distance. In the pneumatic tire for off-road according to Comparative Example 0 to Comparative Example 3, by measuring the indexes of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example, the index obtained by summing the lengths was “100”. In comparison, it was evaluated that the cut resistance of the off-road pneumatic tire according to the example was improved.

<Tire mass test>
The mass of the off-road pneumatic tire according to Comparative Example 0 is set to “100”, and the indices of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example are measured, thereby obtaining Comparative Example 1 and Comparative Example 2. It was evaluated that the mass of the off-road pneumatic tire according to the example was reduced as compared with the off-road pneumatic tire. In addition, it shows that there are few masses, so that an index | exponent is small.

<Noise test>
The noise of the off-road pneumatic tire according to Comparative Example 0 is set to “100”, and the indexes of Comparative Example 1, Comparative Example 2, Comparative Example 3, and Example are measured (the noise value under the ISO vehicle exterior noise condition is an index) It was evaluated that the noise of the off-road pneumatic tire according to the example was reduced as compared with the off-road pneumatic tire according to Comparative Example 1. In addition, it shows that noise is so small that an index | exponent is small.

(Operation and effect of off-road pneumatic tires)
According to the pneumatic tire 10 for off-road according to the present embodiment described above, a triaxial fabric using a predetermined organic fiber, a predetermined inorganic fiber, or a predetermined metal fiber is impregnated with a rubber component. Since the constructed cord reinforcing layer 30 is disposed in the tire circumferential direction from the sidewall portion 27 to the tread shoulder portion 28, noise and an increase in the mass of the tire can be prevented and cut resistance can be improved.

  In addition, according to the pneumatic tire 10 for off-road according to the present embodiment, since the stiffness distribution is oriented in the tire circumferential direction, the impact when rocks and rubble contact with the tire is dispersed, so that the cut resistance is improved. Further improvement can be achieved.

  Furthermore, according to the off-road pneumatic tire 10 according to the present embodiment, predetermined organic fibers (aromatic polyamide fiber, fatty acid polyamide fiber, polyester fiber, polyparaphenylenebenzeneoxazole fiber, polyvinyl alcohol-based synthetic fiber, or carbon fiber) ), A predetermined inorganic fiber (glass fiber) or a predetermined metal fiber (steel wire) is used for the triaxial woven fabric, so that the cut resistance can be improved more effectively.

1 is a partially exploded perspective view of an off-road pneumatic tire 10 according to an embodiment of the present invention. 1 is a cross-sectional view of an off-road pneumatic tire 10 according to an embodiment of the present invention. 1 is an enlarged plan view of a cord reinforcement layer 30 in an off-road pneumatic tire 10 according to an embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Off-road pneumatic tire, 21 ... Tread part, 22 ... Carcass layer, 23 ... Bead part, 23a ... Bead core, 23b ... Bead filler, 24 ... Belt layer, 24a ... First belt, 24b ... Second belt, 25 ... Side tread, 27 ... Side wall part, 28 ... Tread shoulder part, 30 ... Cord reinforcing layer, 30A ... Triaxial fabric

Claims (5)

A carcass layer that is the skeleton of a pneumatic tire for off-road,
A tread portion disposed on the outer side in the tire radial direction of the carcass layer;
A triaxial woven fabric in which cords arranged along three axial directions intersecting each other and arranged in the tire circumferential direction and the tire radial direction outside of the carcass layer are woven together in either the sidewall portion or the tread shoulder portion. A cord reinforcing layer configured by being impregnated with a rubber component;
The off-road pneumatic tire characterized in that the cord constituting the triaxial woven fabric is formed of at least one of a predetermined organic fiber, a predetermined inorganic fiber, and a predetermined metal fiber. The first axis of the three-axis fabric is arranged along the tire circumferential direction,
2. The off-road pneumatic according to claim 1, wherein the second axis and the third axis of the triaxial fabric are arranged at an angle of 60 ° or less with respect to the first axis. tire.   The predetermined organic fiber is an aromatic polyamide fiber, a fatty acid polyamide fiber, a polyester fiber, a polyparaphenylene benzene oxazole fiber, a polyvinyl alcohol-based synthetic fiber, or a carbon fiber. Off-road pneumatic tire.   The pneumatic tire for off-road according to claim 1 or 2, wherein the predetermined inorganic fiber is a glass fiber.   The pneumatic tire for off-road according to claim 1 or 2, wherein the predetermined metal fiber is a steel wire.