JP2007083914A - Pneumatic tire, and its mounting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of compatibly realizing the actual vehicular traveling performance including the steering stability and the ride comfort, the weight reduction and the high-speed durability. <P>SOLUTION: The pneumatic tire has a one-ply structure in which the fitting direction of face and back sides of the tire when fitted to a vehicle is designated, a carcass layer 4 consisting of a plurality of aligned carcass cords is stretched between a pair of bead parts 3, 3, and the carcass layer 4 is turned up from the inside to the outside of the tire around a bead core 5. The carcass cords C are oriented in the tire radial direction in a body portion 4a of the carcass layer 4 while the carcass cords C are inclined with respect to the tire radial direction in a turned-up portion 4b of the carcass layer 4. The included angles Aui, Auo formed by the carcass cords C in the body portion 4a of the carcass layer 4 and the carcass cords C of the turned-up portion of the carcass layer 4 is set in a range of 3-30° on the inner side (IN) and the outer side (OUT) of the vehicle, respectively, and the included angle Auo on the outer side of the vehicle is set to be larger than the included angle Aui on the inner side of the vehicle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic tire suitable for high-speed driving, and more particularly, a pneumatic tire that can achieve a high level of both real-vehicle driving performance including steering stability and riding comfort, light weight, and high-speed durability. Regarding tires.

  In recent years, with respect to pneumatic tires for high-speed driving, in addition to demands for improving driving stability on dry road surfaces and wet road surfaces, demands for improving riding comfort are also increasing. Control of tire stiffness is becoming increasingly difficult. Furthermore, in consideration of vehicle specifications, it is also required to ensure high-speed durability under conditions with a camber. On the other hand, in recent years when environmental efforts have been strengthened, the demand for weight reduction of tires has become increasingly severe.

In view of such circumstances, attempts have been made to optimize tire rigidity based on the carcass structure of a pneumatic tire. For example, in a pneumatic tire in which a carcass layer is mounted between a pair of bead portions and the carcass layer is wound around the bead core from the inside of the tire to the outside, the carcass cord of the carcass layer winding portion is connected to the body portion of the carcass layer. It has been proposed to ensure tire rigidity by crossing the carcass cord (see, for example, Patent Documents 1 to 3). However, even such a method does not satisfy recent required characteristics.
JP 2002-2216 A JP 2002-127712 A JP 2003-226117 A

  An object of the present invention is to provide a pneumatic tire that can achieve a high level of both real-vehicle running performance including steering stability and riding comfort, weight reduction, and high-speed durability.

  In order to achieve the above object, a pneumatic tire according to the present invention is provided with a carcass layer composed of a plurality of aligned carcass cords between a pair of bead portions, in which the mounting direction of the tire front and back is specified when the vehicle is mounted. In the pneumatic tire having a one-ply structure in which the carcass layer is wound around the bead core from the inside to the outside of the carcass layer, the carcass cord is oriented in the tire radial direction in the main body portion of the carcass layer, and the carcass layer is wound up In the portion, the carcass cord is inclined with respect to the tire radial direction, and the included angles Aui and Auo between the carcass cord of the main body portion of the carcass layer and the carcass cord of the rolled-up portion of the carcass layer on the vehicle inner side and the vehicle outer side are 3 respectively. It is characterized in that it is in the range of 30 ° to 30 °, and the outside angle Auo of the vehicle is larger than the inside angle Aui of the vehicle. Is shall.

  In the present invention, a one-ply structure in which the carcass layer is wound around the bead core from the inside of the tire to the outside is adopted for weight reduction. Then, the carcass cord is oriented in the tire radial direction in the main body portion of the carcass layer, and the carcass cord is inclined with respect to the tire radial direction in the rolled-up portion of the carcass layer, and the carcass cord in the main body portion of the carcass layer and the carcass layer Defines the angle between the winding portion and the carcass cord. As a result, the rolled-up portion and the folded-up portion of the carcass layer form a bias laminated structure, and it is possible to exhibit high circumferential rigidity with the minimum necessary constituent materials, so that the handling stability and weight reduction are at a high level. Can be compatible.

  The alignment of vehicles with low flatness and low section height tires is often set to a negative camber, and there is a tendency for the ground reaction force to the sidewall portion inside the vehicle to increase during normal driving. On the other hand, at the time of lane change or turning, the ground reaction force to the sidewall portion outside the vehicle tends to increase. Therefore, in such a tire usage environment, when the vehicle outer side angle Auo is made larger than the vehicle inner side angle Aui, the side rigidity on the vehicle inner side becomes relatively low, so the ride comfort during normal driving is deteriorated. It can be suppressed, and the side rigidity on the outside of the vehicle becomes relatively high, so that it is possible to exhibit excellent steering stability during lane change and turning. Moreover, reducing the side rigidity inside the vehicle also contributes to improving high-speed durability when a negative camber is set.

  In the present invention, it is preferable that the difference between the vehicle outer side angle Auo and the vehicle inner side angle Aui is 2 ° or more. Thereby, it becomes possible to improve steering stability and riding comfort in a well-balanced manner. Further, in order to adjust the side rigidity, the winding height of the carcass layer outside the vehicle is made higher than the winding height inside the vehicle, or the height of the bead filler outside the vehicle is made higher than the height of the bead filler inside the vehicle. It is also effective to increase the height.

  In a pneumatic tire with a specified rotation direction, if the carcass cord winding direction of the carcass layer is the same on the vehicle inner side and the vehicle outer side, and the inclination direction is opposite to the tire rotation direction, The resistance against the side circumference is higher and the traction performance is improved. On the other hand, in a pneumatic tire in which the rotation direction is specified, when the carcass cord roll-up portion of the carcass cord has the same inclination direction on the vehicle inner side and the vehicle outer side, and the inclination direction is the same as the tire rotation direction, The side circumferential rigidity against power is higher and the braking performance is improved.

  The above-described effects can also be obtained by specifying the method of mounting the pneumatic tire regardless of whether or not the rotation direction is specified. That is, a pneumatic tire is prepared in which the vehicle outside angle Auo and the vehicle inside angle Aui are set as described above, and the carcass cord winding direction of the carcass layer is the same in both the vehicle inner side and the vehicle outer side. Then, the pneumatic tire may be mounted on the vehicle so that the inclination direction of the carcass cord is opposite to the tire rotation direction. In addition, a pneumatic tire is prepared in which the vehicle outside angle Auo and the vehicle inside angle Aui are set as described above, and the carcass cord winding direction of the carcass layer is the same in both the vehicle inner side and the vehicle outer side. Then, the pneumatic tire may be mounted on the vehicle so that the inclination direction of the carcass cord is the same as the tire rotation direction.

  In particular, for rear-wheel drive vehicles, the vehicle outside angle Auo and the vehicle inside angle Aui are set as described above, and the carcass cord winding direction of the carcass layer is the same in both the vehicle inner side and the vehicle outer side. A pair of pneumatic tires are prepared, and one of the pneumatic tires is attached to the front wheels of the rear wheel drive vehicle so that the inclination direction of the carcass cord is the same direction as the tire rotation direction, and the other pneumatic tire is The carcass cord is preferably attached to the rear wheel of the rear wheel drive vehicle so that the inclination direction of the carcass cord is opposite to the tire rotation direction. In this case, while improving the traction performance by a rear wheel, the braking performance by a front wheel can be improved.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows a pneumatic tire according to an embodiment of the present invention, FIG. 2 shows an extracted carcass cord near the bead portion inside the vehicle of the pneumatic tire of FIG. 1, and FIG. 3 shows the pneumatic tire of FIG. The carcass cord in the vicinity of the bead portion on the vehicle outer side of the tire is extracted and shown. The pneumatic tire of the present embodiment is designated with the mounting direction of the tire front and back when the vehicle is mounted. The vehicle inner side when the vehicle is mounted is indicated by IN, and the vehicle inner side when the vehicle is mounted is indicated by OUT.

  In FIG. 1, 1 is a tread portion, 2 is a sidewall portion, and 3 is a bead portion. A single carcass layer 4 composed of a plurality of aligned carcass cords is mounted between the pair of bead portions 3 and 3. As the carcass cord, an organic fiber cord made of rayon, polyester, nylon, aromatic polyamide or the like is preferably used. The carcass layer 4 is wound up around the bead core 5 from the inside of the tire to the outside of the tire. That is, the carcass layer 4 is composed of a main body portion 4a and a winding portion 4b.

  A bead filler 6 made of high-hardness rubber is disposed on the outer periphery of the bead core 5, and the bead filler 6 is encased by the rolled-up portion 4 b of the carcass layer 4. A chafer 7 is disposed in the bead portion 3 so as to cover at least a portion from the bead toe to the bead heel. On the other hand, a belt layer 8 including a reinforcing cord that is inclined with respect to the tire circumferential direction is disposed on the outer peripheral side of the carcass layer 4 in the tread portion 1. Further, a belt cover layer 9 including reinforcing cords oriented in the tire circumferential direction is disposed on the outer peripheral side of the belt layer 8.

  In the pneumatic tire, as shown in FIGS. 2 and 3, the carcass cord C is oriented in the tire radial direction in the main body portion 4 a of the carcass layer 4. That is, in the main body portion 4a of the carcass layer 4, the carcass cord angle with respect to the tire circumferential direction is substantially 90 °. On the other hand, the carcass cord C is inclined with respect to the tire radial direction at the winding portion 4b of the carcass layer 4. That is, the carcass cord C of the rolled-up portion 4 b of the carcass layer 4 is arranged so as to intersect the carcass cord C of the main body portion 4 a of the carcass layer 4. Further, the sandwich angles Aui and Auo between the carcass cord C of the main body portion 4a of the carcass layer 4 and the carcass cord C of the rolled-up portion 4b of the carcass layer 4 on the vehicle inner side and the vehicle outer side are set in a range of 3 ° to 30 °, respectively. Has been. In addition, the outside angle Auo of the vehicle is larger than the inside angle Aui of the vehicle.

  Thus, while forming a radial structure with the main-body part 4a of the carcass layer 4, by forming a bias laminated structure with the winding-up part 4b of the carcass layer 4, high circumferential rigidity is exhibited with a minimum necessary constituent material. Can do. Therefore, it is possible to improve the actual vehicle running performance such as steering stability while reducing the weight. Here, when the included angles Aui and Auo between the carcass cord C of the main body portion 4a of the carcass layer 4 and the carcass cord C of the rolled-up portion 4b of the carcass layer 4 are less than 3 °, the side rigidity is insufficient, so that the steering stability is insufficient. In contrast, when the angle exceeds 30 °, the side rigidity is too high, which adversely affects the riding comfort.

  In addition, when the vehicle alignment is set to negative camber, the ground reaction force to the side wall part inside the vehicle tends to increase during normal driving, and the side wall part outside the vehicle during lane change or turning Although the ground reaction force to the vehicle tends to be higher, if the vehicle outer side angle Auo is made larger than the vehicle inner side angle Aui, the side rigidity on the inner side of the vehicle becomes relatively low, thereby suppressing the deterioration of riding comfort. In addition, since the side rigidity on the outside of the vehicle becomes relatively high, it is possible to exhibit excellent steering stability. When tires with a low flatness of section height of 100 mm or less are mounted on a vehicle with a negative camber, if the side stiffness is too high, the high-speed durability tends to decrease, so the side stiffness inside the vehicle should be lowered as described above. Contributes to the improvement of high-speed durability. In particular, the difference between the vehicle outer angle Auo and the vehicle inner angle Aui is preferably 2 ° or more.

  In order to adjust the side rigidity, the hoisting height Tuho on the vehicle outer side of the carcass layer 4 may be set higher than the hoisting height Tuhi on the inner side of the vehicle. Thus, the balance between steering stability and riding comfort can be adjusted by making the winding height of the carcass layer 4 different between the vehicle inner side and the vehicle outer side. That is, the steering stability improves as the winding height Tuho on the vehicle outer side of the carcass layer 4 is increased, and the riding comfort improves as the winding height Tuhi on the vehicle inner side of the carcass layer 4 is decreased.

  Further, in order to adjust the side rigidity, the height Fho of the bead filler 6 on the vehicle outer side may be made higher than the height Fhi of the bead filler 6 on the vehicle inner side. Thus, by making the height of the bead filler 6 different between the inside of the vehicle and the outside of the vehicle, the balance between the handling stability and the riding comfort can be adjusted. That is, as the height Fho of the bead filler 6 on the vehicle outer side is increased, the steering stability is improved, and as the height Fhi of the bead filler 6 on the vehicle inner side is decreased, the riding comfort is improved.

  2 and 3, the inclination direction of the carcass cord C of the winding portion 4b of the carcass layer 4 is the same on the vehicle inner side and the vehicle outer side. Here, when the direction indicated by the arrow R1 is the tire rotation direction and the inclination direction of the carcass cord C of the winding portion 4b of the carcass layer 4 is the direction opposite to the tire rotation direction (R1), the side circumference against the driving force The rigidity becomes higher and the traction performance is improved. On the other hand, when the direction indicated by the arrow R2 is the tire rotation direction, and the inclination direction of the carcass cord C of the winding portion 4b of the carcass layer 4 is the same direction as the tire rotation direction (R2), the side circumferential rigidity against the braking force is It becomes higher and the braking performance is improved.

  In particular, for rear-wheel drive vehicles, a pneumatic tire is mounted on the rear wheel so that the direction of the arrow R1 is the tire rotation direction, and a pneumatic tire is mounted on the front wheel so that the direction of the arrow R2 is the tire rotation direction. Thus, the traction performance by the rear wheels can be improved, and the braking performance by the front wheels can be improved.

  In the pneumatic tires of tire size 245 / 40R18, tires of conventional examples, examples 1 to 3 and comparative examples 1 to 3 having different carcass structures were manufactured.

  In the conventional tire, a single carcass layer having a half radial structure is formed of a main body portion and a rolled-up portion. In the tires of Examples 1 to 3 and Comparative Examples 1 and 2, a single carcass layer having a radial structure is composed of a main body portion and a rolled-up portion. In the tire of Comparative Example 3, two carcass layers having a radial structure are formed of a main body portion and a rolled-up portion. The angle Aui between the carcass cord of the carcass layer main body portion and the carcass cord winding portion of the carcass layer on the inner side of the vehicle, and the angle between the carcass cord main body portion of the carcass layer and the carcass cord folded portion of the carcass layer on the outer side of the vehicle Auo is as shown in Table 1. Moreover, the winding height of the carcass layer was 55 mm, and the height of the bead filler was 35 mm.

  These test tires were evaluated for steering stability, riding comfort, high-speed durability, and mass by the following test methods, and the results are also shown in Table 1.

Steering stability:
The test tire was fitted to a wheel with a rim size of 18 × 8 J and mounted on a vehicle with a displacement of 5000 cc, and sensory evaluation was performed by a driver under the condition of an air pressure of 230 kPa. The evaluation results are shown as an index with the conventional example being 100. The larger the index value, the better the steering stability.

Ride comfort:
The test tire was fitted to a wheel with a rim size of 18 × 8 J and mounted on a vehicle with a displacement of 5000 cc, and sensory evaluation was performed by a driver under the condition of an air pressure of 230 kPa. The evaluation results are shown as an index with the conventional example being 100. The larger the index value, the better the riding comfort.

High speed durability:
An indoor drum durability test was performed on the test tire. In the indoor drum endurance test, the load was 85% of the maximum load capacity, the air pressure was 300 kPa, the camber angle was -2 °, the initial speed was 260 km / h, the speed was increased by 10 km / h every 10 minutes, and the tire failed. The mileage until it was generated was measured. The evaluation results are shown as an index with the conventional example being 100. It means that high speed durability is excellent, so that this index value is large.

mass:
The mass of the test tire was measured. The evaluation results are shown as an index with the conventional example being 100. A smaller index value means a lighter weight.

  As shown in Table 1, the tires of Examples 1 to 3 have a mass equivalent to that of the conventional example, but are controlled by optimizing the vehicle inner side angle Aui and the vehicle outer side angle Auo. Stability, riding comfort, and high-speed durability were improved in a well-balanced manner.

  On the other hand, in the tire of Comparative Example 1, the comfort angle and high-speed durability were lower than those of the conventional example because the included angle Auo outside the vehicle was too large. In the tire of Comparative Example 2, the steering angle Aui on the vehicle inner side and the pinching angle Auo on the vehicle outer side are too small, so that the steering stability is lower than that of the conventional example. Since the tire of Comparative Example 3 was simply provided with two carcass layers, the effect of improving steering stability was not obtained, and the mass was increased.

It is meridian sectional drawing which shows the pneumatic tire which consists of embodiment of this invention. FIG. 2 is a side view showing an extracted carcass cord in the vicinity of a bead portion inside the vehicle of the pneumatic tire of FIG. 1. FIG. 2 is a side view showing an extracted carcass cord in the vicinity of a bead portion on the vehicle outer side of the pneumatic tire of FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Carcass layer 4a Main body part 4b Roll-up part 5 Bead core 6 Bead filler 7 Chafer 8 Belt layer 9 Belt cover layer C Carcass cord IN Vehicle inside OUT Vehicle outside

Claims (9)

  The mounting direction of the tire front and back when the vehicle is mounted is specified, and a carcass layer made up of a plurality of aligned carcass cords is mounted between a pair of bead portions, and the carcass layer extends from the inside of the tire to the outside around the bead core. In the pneumatic tire having a one-ply structure wound up, the carcass cord is oriented in the tire radial direction in the main body portion of the carcass layer, and the carcass cord is inclined with respect to the tire radial direction in the rolled-up portion of the carcass layer, The included angles Aui and Auo between the carcass cord of the main body portion of the carcass layer and the carcass cord of the rolled-up portion of the carcass layer on the inner side and the outer side of the vehicle are in the range of 3 ° to 30 °, respectively, and the included angle Auo on the outer side of the vehicle Is a pneumatic tire that is larger than the included angle Aui inside the vehicle.   The pneumatic tire according to claim 1, wherein a difference between a vehicle-side narrow angle Auo and a vehicle-side narrow angle Aui is 2 ° or more.   The pneumatic tire according to claim 1 or 2, wherein a winding height of the carcass layer on the outside of the vehicle is higher than a winding height on the inside of the vehicle.   The pneumatic tire according to claim 1, wherein the height of the bead filler on the vehicle outer side is higher than the height of the bead filler on the vehicle inner side.   In the pneumatic tire in which the rotation direction is designated, the inclination direction of the carcass cord of the winding portion of the carcass layer is the same on the vehicle inner side and the vehicle outer side, and the inclination direction is opposite to the tire rotation direction. 4. The pneumatic tire according to any one of 4 above.   In the pneumatic tire in which the rotation direction is designated, the inclination direction of the carcass cord of the winding portion of the carcass layer is the same on the vehicle inner side and the vehicle outer side, and the inclination direction is the same direction as the tire rotation direction. 4. The pneumatic tire according to any one of 4 above.   A pneumatic tire according to any one of claims 1 to 4, wherein a pneumatic tire having the same direction of inclination of the carcass cord at the rolled-up portion of the carcass layer on the vehicle inner side and the vehicle outer side is prepared, A pneumatic tire mounting method in which a pneumatic tire is mounted on a vehicle such that the direction of inclination of the carcass cord is opposite to the tire rotation direction.   A pneumatic tire according to any one of claims 1 to 4, wherein a pneumatic tire having the same direction of inclination of the carcass cord at the rolled-up portion of the carcass layer on the vehicle inner side and the vehicle outer side is prepared, A pneumatic tire mounting method in which a pneumatic tire is mounted on a vehicle such that the inclination direction of the carcass cord is the same as the tire rotation direction. A pair of pneumatic tires according to any one of claims 1 to 4, wherein a carcass cord winding direction of the carcass layer is made the same in both the vehicle inner side and the vehicle outer side. , One pneumatic tire is mounted on the front wheel of a rear wheel drive vehicle so that the inclination direction of the carcass cord is the same direction as the tire rotation direction, and the other pneumatic tire is attached to the front wheel of the carcass cord A pneumatic tire mounting method in which the rear wheel drive vehicle is mounted on the rear wheel in the opposite direction.

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