JP2010274799A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire having excellent driving performance, braking performance and cornering performance and improving controllability and stability performance. <P>SOLUTION: In this pneumatic tire 1, a bead part 2, a carcass 12 and a bead filler 9 are provided, a belt 11 and a tread 7 are arranged, and side parts 10 are provided. Each of the side parts 10 includes a side reinforcing layer 8 made of rubber-coated fabric of a plurality cords 14 astride a width direction end of the belt 11 and a tire radial direction outermost side end 16 of the bead filler 9. Each cord 14 of the side reinforcing layer 8 is inclined to a normal line n of the circumference O at an intersection of a circumference O with a rotary shaft of the tire 1 as a centerand and the cord 14. A direction of the inclination is the same between both of the side parts 10 of the tire 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tire, and more particularly to a pneumatic tire having excellent driving performance, braking performance, and cornering performance, and improved steering stability performance.

  When a vehicle corners, a pneumatic tire given a steering angle by a steering wheel operation generates an angle difference, that is, a so-called slip angle (SA) between the traveling direction of the vehicle and the direction of the pneumatic tire. generate. The vehicle can change its direction by receiving a moment by the lateral force generated by the pneumatic tire. FIG. 1 is a perspective view showing a rolling state of a pneumatic tire during vehicle cornering.

  Usually, in the region of a small slip angle, the lateral force is proportional to the magnitude of this slip angle. Therefore, as a method for improving the cornering performance of the vehicle, the in-plane shear rigidity of the belt in the tread portion of the tire is increased to suppress the in-plane bending deformation of the belt, or a side reinforcing layer is disposed on the side portion of the tire. By doing so, a method is known in which the rigidity of the side portion is increased to stabilize the posture during cornering of the tire.

  However, merely increasing the rigidity of the belt and the side portion as described above may suppress the deformation of the tire and reduce the ground contact area, which may particularly impair the driving performance of the tire. In contrast, while many inventions try to balance cornering performance and drive performance by devising the material, angle, and height of the side reinforcing layer, the conventional technology can achieve both of these performances. It's hard to say.

  On the other hand, reducing the rigidity of the side part by enlarging the ground contact area of the tire will reduce cornering performance and the front wheels will sink greatly, especially when the vehicle is braked before and after loading. The vehicle becomes very unstable. Further, at that time, the frictional force on the rear wheel side is greatly reduced, so that the braking performance is deteriorated. That is, it is difficult for the conventional technology to provide a pneumatic tire that is well-balanced in terms of driving performance, braking performance, and cornering performance.

  Note that Patent Document 1 proposes an invention in which the drive performance and braking performance are improved, and the inclination angle of the cord of the side reinforcing layer disposed on the side portion is different depending on the drive wheel and the non-drive wheel of the vehicle. However, in the above-described invention, a significant improvement in performance is not seen as compared with a normal tire. In particular, in order to achieve improved cornering characteristics, more detailed devices are required.

JP 59-34905 A

  Therefore, in view of the above problems, an object of the present invention is to provide a pneumatic tire that is excellent in driving performance, braking performance, and cornering performance and excellent in steering stability performance.

  The “driving performance”, “braking performance”, and “cornering performance” described in the present specification refer to the tire stability regarding the vehicle stability that the driver feels during driving, braking, and cornering, respectively. The “steering stability performance” described in the present specification refers to the performance of the tire as viewed from the above performance.

  The inventors diligently studied how to improve braking performance and cornering performance while ensuring sufficient driving performance, and found that side reinforcement layers made of rubberized cloth of multiple cords were appropriately applied to the side portion of the tire. It has been found that the above-described performance can be improved in a balanced manner by the arrangement, and the present invention has been completed.

That is, the gist configuration of the present invention that satisfies the above-described problems is as follows.
(1) A carcass straddling a toroidal shape between a pair of bead portions, the bead portion including a bead filler extending from the bead core to the outer side in the tire radial direction, and a belt and a tread in order on the radially outer side of the crown portion of the carcass A pneumatic tire having a side portion disposed between the tread and the bead portion,
The side portion includes a side reinforcing layer composed of a rubberized cloth of a plurality of cords straddling a width direction end of the belt and a tire radial direction outermost end of the bead filler,
Each cord of the side reinforcement layer is inclined with respect to a normal line of the circumference at the intersection of the circumference with the circumference centered on the rotation axis of the tire and the cord, and the direction of the inclination is on both sides of the tire A pneumatic tire characterized by being identical between the parts.

  Here, “stretching across the width direction end of the belt and the outermost end in the tire radial direction of the bead filler” means that the outermost end in the tire radial direction of the side reinforcing layer is more tire than the end in the width direction of the belt. It means a state in which the innermost end in the tire radial direction of the side reinforcing layer is located on the inner side in the tire radial direction with respect to the outermost end in the tire radial direction of the bead filler.

  Further, the direction of the inclination of the cord is “the same between both side portions of the tire” means that the direction of the cord of the reinforcing layer disposed on both side portions is the rotation direction of the tire when the tire rolls. To say that it is the same. In that case, the magnitude | size of the inclination | tilt angle with respect to the said normal line of a code | cord | chord may differ between both the reinforcement layers of a tire.

(2) The pneumatic tire according to (1), wherein a tire width direction distance between a tire radial direction outermost end of the side reinforcing layer and a width direction end of the belt is within 5 mm.

(3) The air according to (1) or (2), wherein a distance in a tire radial direction between a tire radial innermost end of the side reinforcing layer and a tire radial outermost end of the bead filler is 5 mm or more. Tires.

(4) The pneumatic tire according to any one of (1) to (3), wherein an inclination angle of the cord of the side reinforcing layer with respect to the normal line is 10 to 70 °.

(5) The pneumatic tire according to (4), wherein an inclination angle of the cord of the side reinforcing layer with respect to the normal is 30 to 60 °.

(6) The pneumatic tire according to any one of (1) to (5), wherein the side reinforcing layer includes a cord made of an organic fiber.

(7) The pneumatic tire according to (6), wherein the side reinforcing layer has a cord made of carbon fiber.

(8) The pneumatic tire according to (6), wherein the side reinforcing layer includes a cord made of an aromatic polyamide.

(9) The pneumatic tire according to any one of (1) to (5), wherein the side reinforcing layer has a cord made of glass fiber.

(10) The pneumatic tire according to any one of (1) to (9), wherein the carcass includes a cord made of a heat-shrinkable material.

(11) In mounting the pneumatic tire according to any one of (1) to (10) above on a front wheel of a vehicle, each cord of the side reinforcing layer includes a circumference centered on the rotation axis of the tire, A mounting method in which the normal line of the circumference at the intersection with the cord is attached so as to be inclined in the tire rotation direction when the vehicle moves forward with respect to a portion outside the circumference.

(12) When the pneumatic tire according to any one of (1) to (10) above is further mounted on the rear wheel of the vehicle, each cord of the side reinforcing layer moves forward with respect to the normal line. The mounting method according to (11), wherein the mounting is performed so as to incline in a direction opposite to the tire rotation direction.

  According to the present invention, it is possible to provide a pneumatic tire that improves driving performance, braking performance, and cornering performance in a well-balanced manner and that is excellent in steering stability performance.

It is a perspective view which shows the mode of the behavior of the pneumatic tire at the time of giving a rudder angle. It is a width direction sectional view of one embodiment of a pneumatic tire by the present invention. It is a side view which shows rolling of the pneumatic tire 1 by this invention when it mounts | wears with the vehicle with the suitable mounting method by this invention. It is width direction sectional drawing of the pneumatic tire as a comparative example. It is sectional drawing of the width direction of the pneumatic tire as a prior art example.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 2 is a cross-sectional view in the width direction of an embodiment of a pneumatic tire according to the present invention. A pneumatic tire 1 shown in FIG. 2 has a carcass 12 straddling a toroidal shape between a pair of bead portions 2, and includes a bead filler 9 extending outward from the bead core 3 of the bead portion 2 in the tire radial direction. The belt 11 and the tread 7 are arranged in order on the radially outer side of the portion, and the side portion 10 is provided between the tread 7 and the bead portion 2.

  In the illustrated example, the carcass 12 is composed of two carcass layers 4a and 4b having a plurality of ply cords that are radial, that is, perpendicular to the equator C of the tire. In the illustrated example, the belt 11 includes inclined belt layers 5a and 5b, and a spiral reinforcing layer 6 is disposed on the outer side in the tire radial direction of the inclined belt layers 5a and 5b. The inclined belt layers 5a and 5b are laminated so that the mutual ply cords have a target inclination angle with respect to the equator plane C of the tire. The spiral reinforcing layer 6 is formed by spirally winding a ribbon-like strip formed by integrally rubber-coating organic fiber cords arranged in parallel with each other.

  Here, in the pneumatic tire 1 according to the present invention, the side portion 10 is rubberized with a plurality of cords 14 straddling the width direction end 15 of the belt 11 and the tire radial direction outermost end 16 of the bead filler 9. A side reinforcing layer 8 made of cloth is provided, and each cord 14 of the side reinforcing layer 8 has a normal line n of the circumference O at the intersection of the circumference O around the rotation axis of the tire and the cord 14. It is important that the direction of the inclination is the same between both side portions of the tire.

  Note that “stretching across the width direction end 15 of the belt 11 and the outermost end 16 in the tire radial direction of the bead filler 9” means that the outermost end 17 in the tire radial direction of the side reinforcing layer 8 as shown in the illustrated example. However, the innermost end 18 in the tire radial direction of the side reinforcing layer 8 is located on the inner side in the tire radial direction than the end 15 in the widthwise direction of the belt 11, and the outermost end 16 in the tire radial direction of the bead filler 9 in the tire. The state located inside the width direction is said.

  In addition, the direction of the inclination of the cord 14 is “the same between the two side portions 10 of the tire” means that the direction of the cord 14 of the reinforcing layer 8 disposed on the both side portions 10 rolls the tire. It is said that it is the same with respect to the rotation direction of the tire. At this time, the inclination angle θ of the cord 14 with respect to the normal line n may be different between the two reinforcing layers 8 of the tire.

  The tire structure necessary for the present invention has been described above. Hereinafter, a mounting method when the pneumatic tire 1 according to the present invention is mounted on a vehicle will be described. FIG. 3 is a side view showing rolling of the pneumatic tire 1 according to the present invention when mounted on a vehicle by a preferred mounting method according to the present invention.

  In the illustrated example, each cord 14 of the side reinforcement layer 8 of the tire is attached to the front wheel of the vehicle with the normal n of the circumference O at the intersection of the circumference O around the rotation axis of the tire and the cord 14. The pneumatic tire 1 according to the present invention is attached to the outer circumferential portion so as to incline in the tire rotation direction when the vehicle moves forward.

  Further, in the illustrated example, each cord 14 of the tire side reinforcing layer 8 on the rear wheel of the vehicle is opposite to the tire rotation direction when the vehicle moves forward with respect to the outer portion of the circumference O of the normal n. The pneumatic tire 1 according to the present invention is mounted so as to be inclined in the direction. That is, the cord 14 of the pneumatic tire 1 attached to the rear wheel is inclined in the opposite direction with respect to the cord 14 of the pneumatic tire 1 attached to the front wheel.

  Here, when the pneumatic tire 1 of the present invention is mounted on the front wheel of the vehicle, as shown in FIG. 3, each cord 14 of the side reinforcing layer 8 of the tire has a circumference O centered on the rotation axis of the tire and the It is important that the outer periphery of the normal line n of the circumference O at the intersection with the cord 14 is attached so as to incline in the tire rotation direction when the vehicle moves forward.

  By mounting the pneumatic tire 1 of the present invention on the front wheels of the vehicle by the above mounting method, it is possible to improve the steering stability performance of the vehicle, specifically, the driving performance, the braking performance, and the cornering performance.

  When mounted by the above mounting method, the cord 14 disposed on the reinforcing layer of the tire receives a force in a tensile direction when the tire receives a frictional force directed from the road surface toward the rear of the vehicle, and the tire faces the vehicle front from the road surface. When receiving frictional force, it receives force in the compression direction. Usually, the cord 14 arranged as a reinforcing material exhibits a strong rigidity against a force in a tensile direction. Therefore, when a tensile force is applied to the cord 14, that is, during braking of the vehicle, the cord 14 acts to suppress deformation of the tire. As a result, it is possible to suppress the sinking due to the load movement before and after the braking of the vehicle, which was a conventional problem, and to stabilize the vehicle during the braking.

  On the other hand, the cord 14 arranged as the reinforcing material hardly exhibits rigidity in the compression direction. For this reason, the tire of the present invention mounted on the front wheel by the above-described method causes a moderate deflection deformation when the vehicle is driven. Thus, it is preferable that the front wheel portion of the vehicle is appropriately deformed to ensure a ground contact area when the vehicle is driven. This makes it possible to stabilize the vehicle during driving.

  Furthermore, since the side reinforcement layer is arranged, the rigidity of the side portion with respect to the vertical direction is improved, so that the posture of the tire during vehicle cornering is stabilized. Therefore, according to the present invention, it is possible to stabilize the vehicle during cornering.

  As described above, in order to exhibit the above-described effect by the cord 14 exhibiting rigidity, the side reinforcing layer 8 is placed on the end portion 15 in the tire radial direction of the belt 11 in the width direction end portion 15 and the bead filler 9 as described above. It is particularly important to dispose it so as to straddle the outer end 16, and thus, driving force and braking force can be reliably transmitted from the wheel of the tire to the tread portion 7. If the side reinforcing layer 8 does not reach either the belt 11 or the bead filler 9 as in the conventional case, the driving force and braking force are absorbed in a portion where the rigidity is reduced. It will not be possible to ensure sufficient steering stability performance.

  In the present invention, when the pneumatic tire 1 according to the present invention is mounted on the front wheel of the vehicle by the mounting method described above, the pneumatic tire 1 of the present invention is further attached to the rear wheel of the tire as shown in the illustrated example. Each cord 14 of the reinforcing layer 8 advances forward with respect to a portion outside the circumference of the normal line n of the circumference O at the intersection of the circumference O around the rotation axis of the tire and the cord 14. It is preferable to mount the tire so as to incline in the direction opposite to the tire rotation direction at the time. That is, it is preferable that the pneumatic tire 1 is mounted on the rear wheel of the vehicle so as to be opposite to the inclination direction of the cord 14 of the pneumatic tire 1 mounted on the front wheel of the vehicle.

  In general, the rear wheel of a vehicle receives a large frictional force from the road surface toward the rear of the vehicle during driving. Conventionally, the rear wheel tire does not exhibit sufficient rigidity with respect to this large frictional force, so that it has been a problem that stability during driving cannot be ensured. In response to this problem, the pneumatic tire 1 of the present invention is further rearranged so that the cord 14 of the side reinforcing layer 8 is opposite to the direction of the cord 14 of the pneumatic tire mounted on the vehicle front wheel by the mounting method of the present invention. By attaching to the wheel, the cord 14 exhibits rigidity against a large frictional force received from the road surface during driving, and can ensure stability during driving. Therefore, it is possible to further improve the steering stability performance of the vehicle.

  In the present invention, the distance t in the tire width direction between the outermost end 17 in the tire radial direction of the side reinforcing layer 8 and the end 15 in the width direction of the belt 11 is preferably within 5 mm.

  Since the inclination angle of the cord disposed on the side reinforcing layer 8 is different from the inclination angle of the cord disposed on the belt layer in the belt 11, if the area of the overlapping portion of both is excessively large, the shoulder portion of the tire There is a possibility that the influence of the in-plane shear rigidity of the side reinforcing layer 8 may occur. However, the area of the overlapping portion is appropriately small, specifically, the distance in the tire width direction between the tire radial direction outermost end 17 of the side reinforcing layer 8 and the width direction end 15 of the belt 11 is within 5 mm. As a result, the possibility can be eliminated, and the effect of the present invention can be obtained more safely.

  Furthermore, in the present invention, the tire radial distance s between the tire radial innermost end 18 of the side reinforcing layer 8 and the tire radial outermost end 16 of the bead filler 9 is preferably 5 mm or more.

  Usually, the bead part 2 of a pneumatic tire is often made of a relatively hard rubber material, and the amount of deformation due to rolling of the tire is small. Therefore, the bead portion is not affected by the in-plane shear rigidity of the side reinforcing layer 8. On the other hand, since the side reinforcing layer 8 and the bead portion 2 are more firmly coupled by deeply superposing the side reinforcing layer 8 on the bead portion, the driving performance and braking performance from the wheel can be transmitted with higher accuracy. Can do. When the overlapping width s between the side reinforcing layer 8 and the bead filler 9 is 5 mm or more, the side reinforcing layer 8 is bonded to the bead portion 2 sufficiently firmly. Therefore, in the present invention, the overlap width s is preferably 5 mm or more.

  In the illustrated example, each cord 14 of the tire side reinforcing layer 8 is a vehicle with respect to a normal line n of the circumference O at the intersection of the circumference O around the rotation axis of the tire and the cord 14. Inclined at an angle θ in the tire rotation direction during forward movement.

  Here, in the present invention, the angle θ is preferably, and more preferably 30 ° ≦ θ ≦ 60 °. The cord 14 exhibits rigidity effectively against the frictional force of the road surface by setting the angle θ to 10 ° ≦ θ ≦ 70 °, and is most effective by setting 30 ° ≦ θ ≦ 60 °. Can exhibit rigidity. Since the cord 14 exhibits rigidity against the frictional force of the road surface, the vehicle during driving, braking, and cornering can be more stabilized.

  In addition, in the present invention, the side reinforcing layer 8 preferably has a cord 14 made of organic fiber, and more preferably has a cord 14 made of carbon fiber or aromatic polyamide.

  A cord made of organic fiber, aromatic polyamide and glass fiber generally has a high elastic modulus against tensile deformation. Therefore, by providing the cord 14 made of the above material on the side reinforcing layer 8, the rigidity of the tire against the frictional force from the road surface is further improved. In addition, the above-described material has a low elastic modulus and is flexible with respect to compressive deformation, and thus it is difficult to inhibit the deformation of the tire necessary for traveling. Therefore, it is convenient for compatibility with other performances.

  In the present invention, the side reinforcing layer 8 preferably has a cord 14 made of glass fiber. The glass fiber has a large elastic modulus against tensile deformation like the above-mentioned material. Therefore, by providing the cord 14 made of glass fiber on the side reinforcing layer 8, it is possible to increase the rigidity of the tire against the frictional force from the road surface as described above.

  Furthermore, in the present invention, the carcass 12 preferably has a ply cord made of a material having heat shrinkability. This is because by providing a ply cord made of a heat-shrinkable material on the carcass 12 of the tire, the ply cord increases in strength with an increase in temperature when the vehicle travels, and improves steering stability performance.

Hereinafter, the present invention will be described in more detail with reference to examples.
4 is a cross-sectional view in the width direction of a pneumatic tire as a comparative example, and FIG. 5 is a cross-sectional view in the width direction of a pneumatic tire as a conventional example. The pneumatic tire 200 shown in FIG. 4 has side reinforcing layers 8 that overlap only the bead filler 9 and do not straddle the belt 11 on both sides of the tire, and the other structure is the pneumatic tire 1 shown in FIG. Is equivalent to the structure of Moreover, the pneumatic tire 300 shown in FIG. 5 does not have a side reinforcement layer, and the other structure is equal to the structure of the pneumatic tire 1 shown in FIG.

  According to the structure shown in FIG. 2, tires 245 / 45R18 (tire outer diameter 677 mm, rim width 8.5 inches × rim diameter 18 inches), high performance tires for passenger cars, invention tires 1 to 9 according to the present invention Was made. For high-performance tires for passenger cars of the same size, a comparative tire having the structure shown in FIG. 4 and a conventional tire having the structure shown in FIG. 5 were manufactured. At that time, the angle of the cord disposed on the reinforcing layer, the material, and the width of the reinforcing layer were variously changed for the tires of the inventive example tire and the comparative example tire. Table 1 shows the specifications of the tires. In addition, the direction of inclination of each cord 14 arranged on the side reinforcing layer 8 of the comparative example tire is the same between both side portions 10 of the tire.

Here, each of the tires except the inventive tire 11 shown in Table 1 includes two carcass layers 4a and 4b having a nylon cord having a diameter of 0.5 mm. In the inventive tire 11, the tire has a diameter of 0.9 mm. The two carcass layers 4a and 4b having the polyketone fiber cord are provided. The carcass layers 4 a and 4 b are both radial, that is, have an inclination angle of 90 degrees with respect to the equator, and are folded back via the bead core 3. The two inclined belt layers 5a and 5b that reinforce the crown portion (tread portion 7) of the tire are made of a so-called 1 × 3 type cord in which three pieces of steel having a diameter of 0.18 mm are twisted together with respect to the equator direction. They are arranged to cross each other at an angle of 40 °. The cord driving interval is 35/50 mm.
The tread width TW is 245 mm, the width of the lower inclined belt layer 5a is 240 mm, and the width of the upper inclined belt layer 5b is 220 mm. A spiral reinforcing layer 6 is disposed on the outer side in the tire radial direction of the inclined belt layers 5a and 5b. The spiral reinforcing layer 6 is made of twisted aromatic polyamide (trade name: Kevlar) having a diameter of 0.7 mm. 50 / 50mm. The number of twists of the Kevlar is 30 times / 100 mm (meaning that there are 30 twists in a cord length of 100 mm). The spiral reinforcing layer 6 has a width of 250 mm and is formed of one layer for all layers. The spiral reinforcing layer 6 was manufactured by arranging two Kevlar cords in parallel and covering them with unvulcanized rubber to form a strip, which was wound around the inclined belt layer at the time of tire molding. A predetermined groove is arranged in the tread portion 7.

  The “angle θ of the cord used for the side reinforcement layer” shown in Table 1 is relative to the normal n of the circumference O at the intersection of the circumference O around the rotation axis of the tire and the cord 14. The inclination angle of the cord 14 is the same between the two side portions 10 of the tire.

In addition, the description in the column “Material of Side Reinforcement Layer” in Table 1 is as shown in detail below.
<Nylon>
Nylon cords with a diameter of 0.7 mm are arranged at a driving number of 55/50 mm, and the number of nylon fiber twists in the nylon cord is 50 times / 100 mm.
<Carbon fiber>
Monofilaments of carbon fibers having a diameter of 0.1 mm are arranged at 250 pieces / 50 mm.
<Aramid>
Aramid fiber cords having a diameter of 0.9 mm are arranged at a driving number of 35/50 mm, and the number of twisted aramid fibers in the aramid fiber cord is 30 times / 100 mm.
<Glass fiber>
Glass filament monofilaments having a diameter of 0.1 mm are arranged at 250 pieces / 50 mm.
As a material of the carcass in the tire 11 of the invention, a polyketone fiber cord having a diameter of 0.9 mm is arranged at a driving number of 35/50 mm, and the number of polyketone fibers in the polyketone fiber cord is 30 times / 100 mm.
The rubber sheet of each side reinforcing layer is the same quality as the belt coating rubber.

Further, the description in the column of “width of side reinforcing layer” in Table 1 is as shown in detail below.
<Bead to bead>
The structure of the side reinforcing layer 8 of the tire shown in FIG. 2 is such that the distance t is t = 5 mm and the distance s is s = 25 mm.
<Bead from the side>
4 is a structure of the side reinforcing layer 8 of the tire shown in FIG. 4, and the outermost end in the tire radial direction of the side reinforcing layer 8 is 10 mm outside from the width direction end of the belt 11 in the path length on the carcass layers 4a and 4b. is there. The innermost end in the tire radial direction of the side reinforcing layer 8 is 25 mm inside in the tire radial direction from the outermost end in the tire radial direction of the bead filler 9.

  The tires thus obtained were assembled into rims and mounted on a rear-wheel drive sports-type vehicle, and then a test course run by an experienced driver was carried out. At that time, the tires to be mounted on the front and rear sides of the vehicle and the directions of the tires were switched in various ways, and were carried out as Conventional Example 1, Comparative Examples 1 and 2, and Invention Examples 1 to 12, respectively. In order to investigate the steering stability performance at the limit, we ran hard and the maximum speed reached 200 km / h. At that time, driving performance, braking performance and cornering performance were evaluated with a maximum of 10 points, and further, steering stability performance was evaluated by combining these performances. Table 2 shows the test results.

In the column of “Installed tire and installation direction” in Table 2, “Subordinate” indicates the conventional tire described in Table 1, “Ratio” indicates the comparative tire described in Table 1, and “ “1” to “11” indicate the inventive tire 1 to the inventive tire 11 described in Table 1.
The description of (positive) and (negative) in the same column is as shown below. The conventional tire has no side reinforcement layer and does not need to be distinguished from the tire direction, so that <positive> and <negative> are not described.
<Correct>
Each cord 14 of the side reinforcement layer 8 of the tire is in relation to a portion outside the circumference of the normal line n of the circumference O at the intersection of the circumference O around the tire rotation axis and the cord 14. It shows that the tire is mounted so as to incline in the tire rotation direction when the vehicle moves forward. That is, it is the direction of the front wheel in FIG.
<negative>
Each cord 14 of the side reinforcement layer 8 of the tire is in relation to a portion outside the circumference of the normal line n of the circumference O at the intersection of the circumference O around the tire rotation axis and the cord 14. It shows that the vehicle is mounted so as to incline in the direction opposite to the tire rotation direction when the vehicle moves forward. That is, it is the direction of the rear wheel in FIG.

  Conventional Example 1 is a tire in which a conventional tire 1 shown in Table 1 is mounted on a front wheel and a rear wheel of a vehicle. Inventive Example 1 is a positive direction of an inventive tire 7 shown in Table 1 on a front wheel of a vehicle. The conventional tire is mounted on the rear wheel of the vehicle. From Table 2, it can be seen that Invention Example 1 is greatly superior to the conventional example in terms of performance. This is because the rigidity of the front wheels of the vehicle, in particular, the rigidity against the large frictional force received from the road surface during braking is effectively improved by mounting the tire 7 of the invention on the front wheels of the vehicle in the positive direction. It is.

  Inventive Examples 2 to 8 are those in which the inventive tires 1 to 7 shown in Table 1 are mounted on the front wheels of the vehicle in the positive direction and mounted on the rear wheels of the vehicle in the negative direction. Here, the inventive tires 1 to 7 are tires according to the present invention in which nylon cords are arranged on the side reinforcing layers, and the inclination angles θ of the cords are different. From Table 2, it can be seen that the steering stability performance of the tire tends to improve as the inclination angle θ of the cord disposed in the side reinforcing layer approaches θ = 40 °.

  That is, Invention Examples 4 to 8 in which the inclination angle θ is 10 ° ≦ θ ≦ 70 ° are superior in performance to Invention Examples 2 and 3 in which the inclination angle θ is outside the above range, Invention Examples 6 to 8 in which the inclination angle θ is 30 ° ≦ θ ≦ 60 ° are more stable than the invention examples 4 and 5 in which the inclination angle θ is outside the range of 30 ° ≦ θ ≦ 60 °. Excellent performance.

  This is because the tensile rigidity of the cord acts more effectively on the frictional force received from the road surface by inclining the cord of the side reinforcing layer at an appropriate angle. From the above results, it is understood that in the present invention, the inclination angle θ is preferably 10 ° ≦ θ ≦ 70 °, and more preferably 30 ° ≦ θ ≦ 60 °.

  Further, from Table 2, Invention Example 8 in which the inventive tire 7 is appropriately attached to the front and rear wheels is superior in steering stability performance to Invention Example 1 in which the same inventive tire 7 is attached only to the front wheels. Recognize. This is because the rigidity of the rear wheel of the vehicle, in particular, the rigidity against the large frictional force received from the road surface during driving is effectively improved by mounting the tire of the invention on the rear wheel in the negative direction. It is. Therefore, in the present invention, it can be said that the pneumatic tire according to the present invention is preferably attached to the vehicle rear wheel in the negative direction.

  Inventive Examples 9 to 11 are the same as the Inventive Example Tire 7 used in Inventive Example 8, but the Inventive Example Tires 8 to 10 having different materials of the side reinforcing layers are attached to the front wheels in the positive direction. , Mounted on the rear wheel of the vehicle in the negative direction. From Table 2, it can be seen that Invention Examples 9 to 11 are superior to Invention Example 8 for each performance. That is, the inventive tire 8 having a cord made of carbon fiber in the side reinforcing layer, the inventive tire 9 having a cord made of aramid, that is, an aromatic polyamide, in the side reinforcing layer, and a cord made of glass fiber in the side reinforcing layer. It can be said that the inventive example tire 10 has excellent steering stability performance as compared with the inventive example tire 7 using a nylon cord as a side reinforcing layer.

  This is because the rigidity of the tire against the frictional force from the road surface can be further improved by using the above material having a large elastic modulus against tensile deformation as a cord and providing the cord on the side reinforcing layer. From the above results, in the present invention, it can be said that the side reinforcing layer preferably has a cord made of carbon fiber, aromatic polyamide, or glass fiber.

  Inventive Example 12 has the same structure as that of Inventive Example Tire 7 used in Inventive Example 8, and the material of the carcass layer is polyketone fiber, that is, a material having heat shrinkability. From Table 2, it can be seen that Invention Example 12 is superior to Invention Example 8 for each performance. In other words, the inventive tire 11 having a cord made of polyketone fiber, that is, a heat-shrinkable material, in the carcass layer is superior in steering stability performance than the inventive tire 7 using a nylon cord in the carcass layer. I understand.

  This is because the cord made of the heat-shrinkable material shrinks as the temperature of the tire increases due to running of the vehicle and increases the tensile strength, thereby effectively increasing the rigidity of the tire. From the above results, it can be said that in the present invention, the carcass layer preferably has a cord made of a material having heat shrinkability.

  In Comparative Example 1, the comparative example tire 1 in which the side reinforcing layer does not reach the end in the width direction of the belt is mounted on the front wheel of the vehicle in the positive direction and mounted on the rear wheel of the vehicle in the negative direction. From Table 2, it can be seen that Comparative Example 1 does not show a significant advantageous effect over the conventional example in each performance, and has almost the same steering stability performance.

  This is because, in the comparative tire 1 described above, since the side reinforcing layer does not reach the belt, the driving force and braking force from the wheel are absorbed by the side portion, and sufficient steering stability performance is ensured. Because it was not possible. Accordingly, in the present invention, the side reinforcing layer needs to be disposed so as to straddle the width direction end of the belt and the tire radial direction outermost end of the bead filler.

  In Comparative Example 2, Invention Example 7 shown in Table 1 is mounted on the front wheel of the vehicle in the negative direction and mounted on the rear wheel of the vehicle in the positive direction. From Table 2, it can be seen that Comparative Example 2 was unable to obtain a result higher than that of the conventional example in each performance. This is because the side reinforcing layer does not exhibit sufficient rigidity in accordance with the running of the tire because the direction of the inclination of the cord of the side reinforcing layer is not appropriate.

  According to the present invention, it is possible to provide a pneumatic tire that is excellent in driving performance, braking performance, and cornering characteristics and has improved steering stability performance.

C Tire Equator θ Inclination Angle O of Reinforcement Layer Cord Circumference 1 Pneumatic Tire 2 Bead Part 3 Bead Core 4 Carcass Layer 4a Carcass Layer (Inside)
4b Carcass layer (outside)
5 Inclined belt layer 5a Inclined belt layer (maximum)
5b Inclined belt layer 6 Spiral reinforcing layer 7 Tread part 8 Reinforcing layer 9 Bead filler 10 Side part 11 Belt 12 Carcass 13 Rim 14 Reinforcing layer cord 15 Belt end 16 Tire radial direction outermost end 17 of bead filler Tire diameter of side reinforcing layer Direction outermost end 18 tire radial direction innermost end of side reinforcing layer

Claims (12)

A carcass straddling a toroidal shape between a pair of bead portions, the bead portion including a bead filler extending outward from the bead core in the radial direction of the tire, and a belt and a tread are sequentially arranged on the radially outer side of the crown portion of the carcass, A pneumatic tire having a side portion between the tread and the bead portion,
The side portion includes a side reinforcing layer composed of a rubberized cloth of a plurality of cords straddling a width direction end of the belt and a tire radial direction outermost end of the bead filler,
Each cord of the side reinforcement layer is inclined with respect to a normal line of the circumference at the intersection of the circumference with the circumference centered on the rotation axis of the tire and the cord, and the direction of the inclination is on both sides of the tire A pneumatic tire characterized by being identical between the parts.   The pneumatic tire according to claim 1, wherein a tire width direction distance between a tire radial direction outermost end of the side reinforcing layer and a width direction end of the belt is within 5 mm.   The pneumatic tire according to claim 1 or 2, wherein a tire radial distance between a tire radial innermost end of the side reinforcing layer and a tire radial outermost end of the bead filler is 5 mm or more.   The pneumatic tire according to any one of claims 1 to 3, wherein an inclination angle of the cord of the side reinforcing layer with respect to the normal line is 10 to 70 °.   The pneumatic tire according to claim 4, wherein an inclination angle of the cord of the side reinforcing layer with respect to the normal is 30 to 60 °.   The pneumatic tire according to claim 1, wherein the side reinforcing layer has a cord made of an organic fiber.   The pneumatic tire according to claim 6, wherein the side reinforcing layer has a cord made of carbon fiber.   The pneumatic tire according to claim 6, wherein the side reinforcing layer has a cord made of an aromatic polyamide.   The pneumatic tire according to claim 1, wherein the side reinforcing layer has a cord made of glass fiber.   The pneumatic tire according to claim 1, wherein the carcass has a cord made of a material having heat shrinkability.   When mounting the pneumatic tire according to any one of claims 1 to 10 on a front wheel of a vehicle, each cord of the side reinforcing layer is at an intersection of the circumference around the rotation axis of the tire and the cord. A mounting method in which the tire is mounted so as to incline in a tire rotation direction when the vehicle moves forward with respect to a portion of the circumference normal outside the circumference.   When the pneumatic tire according to any one of claims 1 to 10 is further attached to a rear wheel of the vehicle, each cord of the side reinforcing layer has a tire rotation direction when the vehicle moves forward with respect to the normal line. The mounting method according to claim 11, wherein the mounting is performed so as to incline in the opposite direction.