阅读说明：本技术 轮胎 (Tyre for vehicle wheels ) 是由 青木大亮 今井大树 于 2020-10-12 设计创作，主要内容包括：本发明提供能够以高水平兼顾操纵稳定性能和乘车舒适性能的轮胎。轮胎(1)包括：跨越于一对胎圈芯(5)之间而延伸的胎体(6)、和沿着胎体(6)延伸的一对加强层(9)。胎体(6)具有至少一张胎体帘布(6A),该胎体帘布(6A)包括跨越于一对胎圈芯(5)之间的主体部(6a)、和与主体部(6a)相连并且绕胎圈芯(5)折回的折回部(6b)。加强层(9)分别具有轮胎周向的粘弹性与轮胎径向的粘弹性不同的至少一张各向异性片(9A)。各向异性片(9A)的轮胎径向的外端(9b)位于主体部(6a)与折回部(6b)之间。(The invention provides a tire which can achieve both steering stability performance and riding comfort performance at a high level. A tire (1) comprises: a carcass (6) extending across the pair of bead cores (5), and a pair of reinforcing layers (9) extending along the carcass (6). The carcass (6) has at least one carcass ply (6A), and the carcass ply (6A) includes a main portion (6A) spanning between a pair of bead cores (5), and a folded-back portion (6b) connected to the main portion (6A) and folded back around the bead cores (5). The reinforcing layer (9) has at least one anisotropic sheet (9A) having a viscoelasticity in the tire circumferential direction different from that in the tire radial direction. The outer end (9b) of the anisotropic sheet (9A) in the tire radial direction is located between the main body (6a) and the folded-back portion (6 b).)

1. A tire, characterized in that,

comprising a carcass extending across a pair of bead cores, and a pair of reinforcing layers extending along the carcass,

the carcass has at least one carcass ply including a main portion spanning between a pair of the bead cores, and a folded-back portion joined to the main portion and folded back around the bead cores,

the reinforcing layers each have at least one anisotropic sheet having a viscoelasticity in the tire circumferential direction different from a viscoelasticity in the tire radial direction,

the outer end of the anisotropic sheet in the tire radial direction is located between the main body portion and the folded portion.

2. The tire according to claim 1,

the distance between the outer end of the anisotropic sheet and the end of the folded portion in the tire radial direction is 3-15 mm.

3. Tire according to claim 1 or 2,

the inner end of the anisotropic sheet in the tire radial direction is located on the outer side of the bead core in the tire radial direction.

4. Tire according to claim 3,

the distance between the inner end of the anisotropic sheet and the outer surface of the bead core in the tire radial direction is 3-15 mm.

5. Tire according to any one of claims 1 to 4,

further comprising a pair of bead apexes extending from the bead cores respectively outward in the tire radial direction,

the inner end of the anisotropic sheet in the tire radial direction is located between the main body and the bead apex.

6. Tire according to claim 5,

the outer end of the anisotropic sheet is located further toward the tire radial direction outer side than the outer end of the bead apex in the tire radial direction.

7. A tyre according to anyone of claims 1 to 6,

the anisotropic sheet has a complex elastic modulus Ea in the tire circumferential direction at 70 ℃ greater than a complex elastic modulus Eb in the tire radial direction at 70 ℃.

8. The tire according to claim 7,

the anisotropic sheet has a complex elastic modulus Ea in the tire circumferential direction at 70 ℃ of 110 to 170% of a complex elastic modulus Eb in the tire radial direction at 70 ℃.

9. A tyre according to any one of claims 1 to 8,

the anisotropic sheet includes a bio-nanomaterial.

10. The tire according to claim 9,

the biological nanomaterial comprises nanocellulose.

Technical Field

The present invention relates to a tire including a carcass and a reinforcing layer.

Background

Conventionally, a tire including a carcass extending across a pair of bead cores and a pair of reinforcing layers extending along the carcass is known. For example, patent document 1 listed below proposes a tire in which a hard bead apex serving as a reinforcing layer extends radially outward from a bead along a carcass.

Patent document 1: japanese patent laid-open publication No. 2018-052236

However, in the tire of patent document 1, although the steering stability performance is improved by disposing a hard reinforcing layer, such a hard reinforcing layer becomes an important factor for reducing the ride comfort performance.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and a main object thereof is to provide a tire that can achieve both steering stability performance and ride comfort performance at a high level.

The present invention is a tire characterized in that,

the tire body is provided with at least one carcass cord fabric, the carcass cord fabric comprises a main body part spanning between a pair of bead cores and a folded part connected with the main body part and folded around the bead cores, the reinforcing layers are respectively provided with at least one piece of anisotropic sheet with viscoelasticity in the tire circumferential direction different from that in the tire radial direction, and the outer end of the anisotropic sheet in the tire radial direction is positioned between the main body part and the folded part.

In the tire of the present invention, it is preferable that a distance between the outer end of the anisotropic sheet and an end of the folded portion in the tire radial direction is 3 to 15 mm.

In the tire of the present invention, it is preferable that the inner end of the anisotropic sheet in the tire radial direction is located on the tire radial direction outer side of the outer surface of the bead core in the tire radial direction.

In the tire of the present invention, it is preferable that a distance between the inner end of the anisotropic sheet and the outer surface of the bead core in the tire radial direction is 3 to 15 mm.

In the tire of the present invention, it is preferable that the tire further includes a pair of bead apexes extending from the bead cores to the outer sides in the tire radial direction, respectively, and inner ends of the anisotropic sheet in the tire radial direction are located between the main body and the bead apexes.

In the tire of the present invention, it is preferable that the outer end of the anisotropic sheet is located further toward the outside in the tire radial direction than an outer end of the bead apex in the tire radial direction.

In the tire of the present invention, it is preferable that the anisotropic sheet has a complex elastic modulus Ea in the tire circumferential direction at 70 ℃ of more than a complex elastic modulus Eb in the tire radial direction at 70 ℃.

In the tire of the present invention, it is preferable that the complex elastic modulus Ea at 70 ℃ in the tire circumferential direction of the anisotropic sheet is 110 to 170% of the complex elastic modulus Eb at 70 ℃ in the tire radial direction.

In the tire of the present invention, it is preferable that the anisotropic sheet includes a bio nanomaterial.

In the tire of the present invention, preferably, the bio-nanomaterial includes nanocellulose.

In the tire of the present invention, each of the reinforcing layers has at least one anisotropic sheet having a viscoelasticity in the tire circumferential direction different from that in the tire radial direction. Since such a reinforcing layer can adopt different rigidities in the tire circumferential direction and the tire radial direction, it is possible to achieve both steering stability performance in which rigidity in the tire circumferential direction greatly contributes and ride comfort performance in which rigidity in the tire radial direction greatly contributes.

In the tire of the present invention, the outer end of the anisotropic sheet in the tire radial direction is located between the main body portion and the folded portion. Such an anisotropic sheet can ensure rigidity in the vicinity of the outer end of the anisotropic sheet, and therefore can further improve steering stability performance. Therefore, the tire of the present invention can achieve both the steering stability performance and the ride comfort performance at a high level.

Drawings

FIG. 1 is a cross-sectional view of one embodiment of a tire of the present invention.

Fig. 2 is an enlarged sectional view of a bead portion.

Fig. 3 is an enlarged sectional view of a tire according to another embodiment.

Fig. 4 is an enlarged cross-sectional view of a bead portion of another embodiment.

Description of reference numerals: 1 … tire; 5 … bead core; 6 … tire body; 6a … carcass ply; 6a … body portion; 6b … folded back portion; 9 … a reinforcing layer; 9a … anisotropic sheet; 9a … inner end; 9b … outer end.

Detailed Description

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

Fig. 1 shows a tire meridian cross-sectional view including a rotation axis in a normal state of the tire 1 of the present embodiment. The tire 1 of the present embodiment is suitably used as a pneumatic tire mounted on a passenger car or the like. The tire 1 is not particularly limited to a pneumatic tire for a passenger vehicle, and can be applied to various tires such as a pneumatic tire for a heavy load, a pneumatic tire for a motorcycle, and the like.

Here, the "normal state" refers to a no-load state in which the tire 1 rim is assembled to a normal rim and adjusted to a normal internal pressure. Hereinafter, unless otherwise specified, the dimensions and the like of each portion of the tire 1 are values measured in this normal state.

The "regular Rim" is a Rim specified for each tire in a specification system including the specification under which the tire 1 is based, and is, for example, "standard Rim" in the case of JATMA, "Design Rim" in the case of TRA, and "Measuring Rim" in the case of ETRTO.

The "normal internal PRESSURE" refers to an air PRESSURE specified for each TIRE in a specification system including the specification which the TIRE 1 conforms to, and is "maximum air PRESSURE" in case of JATMA, a maximum value described in a table "TIRE LOAD conditions AT variance cooling PRESSURES" in case of TRA, and "inertia PRESSURE" in case of ETRTO.

As shown in fig. 1, a tire 1 of the present embodiment includes: a tread portion 2 extending in a ring shape, a pair of side wall portions 3 extending on both sides of the tread portion 2, and a pair of bead portions 4 extending continuously from the side wall portions 3. The tire 1 of the present embodiment includes: a toroidal carcass 6 extending across the bead cores 5 of the pair of bead portions 4, and a belt layer 7 disposed on the outer side of the carcass 6 in the tire radial direction and inside the tread portion 2.

The carcass 6 has at least one carcass ply, in this embodiment, one carcass ply 6A. The carcass ply 6A includes, for example, carcass cords (not shown) arranged at an angle of 75 to 90 ° with respect to the tire circumferential direction. For example, an organic fiber cord such as aramid or rayon can be used as the carcass cord.

The carcass ply 6A includes, for example: a main body 6a extending from the tread portion 2 to the bead core 5 of the bead portion 4 through the sidewall 3; and a folded-back portion 6b connected to the main body portion 6 a. The main body 6a of the present embodiment extends across the pair of bead cores 5. The folded portion 6b of the present embodiment is folded around the bead core 5 from the inner side to the outer side in the tire axial direction.

The belt layer 7 includes at least one belt ply, and in the present embodiment, two belt plies 7A and 7B. The two belt plies 7A, 7B include, for example: a first belt ply 7A located on the inner side in the tire radial direction, and a second belt ply 7B located on the outer side of the first belt ply 7A. Such a belt layer 7 can improve the rigidity of the tread portion 2 and improve the durability of the tire 1.

The tire 1 of the present embodiment further includes: a pair of bead apexes 8 extending outward in the tire radial direction from the bead cores 5, and a pair of reinforcing layers 9 extending along the carcass 6. The bead apex 8 is preferably disposed between the main body portion 6A and the folded-back portion 6b of the carcass ply 6A.

Fig. 2 is an enlarged sectional view of the bead portion 4. As shown in fig. 2, the reinforcing layer 9 has at least one anisotropic sheet 9A, in this embodiment, one anisotropic sheet 9A, each having a viscoelasticity in the tire circumferential direction different from that in the tire radial direction. Since the reinforcing layer 9 can adopt different rigidities in the tire circumferential direction and the tire radial direction, it is possible to achieve both of the steering stability performance in which the rigidity in the tire circumferential direction greatly contributes and the ride comfort performance in which the rigidity in the tire radial direction greatly contributes. The reinforcing layer 9 may have a plurality of anisotropic sheets 9A, for example, or may have the anisotropic sheets 9A and a known reinforcing sheet. The thickness of the anisotropic sheet 9A is preferably 0.5 to 1.2 mm.

The inner end 9A of the anisotropic sheet 9A in the tire radial direction is preferably located between the main body portion 6a and the folded-back portion 6b of the carcass 6. The outer end 9b in the tire radial direction of the anisotropic sheet 9A of the present embodiment is located between the main body portion 6a and the folded portion 6 b. Such an anisotropic sheet 9A can ensure rigidity in the vicinity of the outer end 9b of the anisotropic sheet 9A, and therefore, the steering stability performance can be further improved. Therefore, the tire 1 of the present embodiment can achieve both the steering stability performance and the ride comfort performance at a high level.

More preferably, the inner end 9A of the anisotropic sheet 9A is located on the outer side in the tire radial direction than the outer surface 5a in the tire radial direction of the bead core 5. Such an anisotropic sheet 9A can suppress an excessive increase in rigidity of the bead portion 4, and therefore can improve ride comfort performance of the tire 1.

The distance d1 between the inner end 9A of the anisotropic sheet 9A and the outer surface 5a of the bead core 5 in the tire radial direction is preferably 3 to 15 mm. By setting the distance d1 between the inner end 9A of the anisotropic sheet 9A and the outer surface 5a of the bead core 5 to 3mm or more, the strain generated in the anisotropic sheet 9A can be reduced. By setting the distance d1 between the inner end 9A of the anisotropic sheet 9A and the outer surface 5a of the bead core 5 to 15mm or less, the rigidity near the inner end 9A of the anisotropic sheet 9A can be secured. From such a viewpoint, the distance d1 between the inner end 9A of the anisotropic sheet 9A and the outer surface 5a of the bead core 5 is more preferably 5 to 10 mm.

The inner end 9A of the anisotropic sheet 9A of the present embodiment is positioned between the main body 6a of the carcass 6 and the bead apex 8. Such an anisotropic sheet 9A can improve the rigidity of the bead portion 4, and therefore can improve the steering stability performance of the tire 1.

Although not shown, the inner end 9A of the anisotropic sheet 9A may be located between the folded-back portion 6b of the carcass 6 and the bead apex 8, for example. The anisotropic sheet 9A in this case can improve the rigidity of the bead portion 4 on the outer side in the tire axial direction, and can further improve the steering stability of the tire 1.

The outer end 9b of the anisotropic sheet 9A of the present embodiment is located further inward in the tire radial direction than the end 6c of the folded portion 6 b. Since the outer end 9b of the anisotropic sheet 9A is wrapped in the carcass 6, the rigidity change can be dispersed, and the ride comfort of the tire 1 can be improved.

The distance d2 in the tire radial direction between the outer end 9b of the anisotropic sheet 9A and the end 6c of the folded portion 6b is preferably 3 to 15 mm. By setting the distance d2 between the outer end 9b of the anisotropic sheet 9A and the end 6c of the folded portion 6b to 3mm or more, the strain generated in the anisotropic sheet 9A can be reduced. By setting the distance d2 between the outer end 9b of the anisotropic sheet 9A and the end 6c of the folded portion 6b to 15mm or less, the rigidity near the outer end 9b of the anisotropic sheet 9A can be ensured. From such a viewpoint, the distance d2 between the outer end 9b of the anisotropic sheet 9A and the end 6c of the folded portion 6b is more preferably 5 to 10 mm.

The outer end 9b of the anisotropic sheet 9A of the present embodiment is located further outward in the tire radial direction than the outer end 8a of the bead apex 8 in the tire radial direction. Such an anisotropic sheet 9A can improve the rigidity in a wider range, and therefore can further improve the steering stability performance of the tire 1.

The distance d3 between the outer end 9b of the anisotropic sheet 9A and the outer end 8a of the bead apex 8 in the tire radial direction is preferably 10 to 20 mm. By setting the distance d3 between the outer end 9b of the anisotropic sheet 9A and the outer end 8a of the bead apex 8 to 10mm or more, the ride comfort of the tire 1 can be improved. By setting the distance d3 between the outer end 9b of the anisotropic piece 9A and the outer end 8a of the bead apex 8 to 20mm or less, the steering stability of the tire 1 can be improved.

As shown in fig. 1 and 2, the outer end 9b of the anisotropic sheet 9A is preferably located in the vicinity of the tire maximum width position 10. Such an anisotropic sheet 9A can improve the steering stability performance and the ride comfort performance of the tire 1 in a well-balanced manner. Here, the tire maximum width position 10 is a position at which the distance in the tire axial direction of the tire contour other than the projection or the like is maximum.

The outer end 9b of the anisotropic sheet 9A of the present embodiment is located on the tire radial direction inner side than the tire maximum width position 10. Such an anisotropic sheet 9A can suppress an excessive increase in rigidity, thereby improving the ride comfort performance of the tire 1.

The distance d4 between the outer end 9b of the anisotropic sheet 9A and the tire radial direction at the tire maximum width position 10 is preferably 3 to 7 mm. By setting the distance d4 between the outer end 9b of the anisotropic sheet 9A and the tire maximum width position 10 to 3mm or more, the ride comfort of the tire 1 can be improved. By setting the distance d4 between the outer end 9b of the anisotropic sheet 9A and the tire maximum width position 10 to 7mm or less, the steering stability of the tire 1 can be improved.

Fig. 3 is an enlarged cross-sectional view of a tire 1 according to another embodiment, and fig. 4 is an enlarged cross-sectional view of a bead unit 4 according to another embodiment. For example, when the steering stability performance of the tire 1 is important, the outer end 9b of the anisotropic sheet 9A may be located on the tire radial direction outer side than the tire maximum width position 10 as shown in fig. 3. For example, when importance is attached to ride comfort of the tire 1, the outer end 9b of the anisotropic sheet 9A may be located near the outer end 8a of the bead apex 8 as shown in fig. 4. Even in these cases, the outer end 9b of the anisotropic sheet 9A is preferably located further inward in the tire radial direction than the end 6c of the folded portion 6 b.

As shown in fig. 1 and 2, the length L of the anisotropic sheet 9A in the tire radial direction is preferably 20% to 60% of the cross-sectional height H of the tire 1. By setting the length L of the anisotropic sheet 9A to 20% or more of the sectional height H of the tire 1, the rigidity of the sidewall 3 and the bead portion 4 can be appropriately improved, and the steering stability performance of the tire 1 can be improved. By setting the length L of the anisotropic sheet 9A to 80% or less of the sectional height H of the tire 1, excessive increase in rigidity of the sidewall portion 3 and the bead portion 4 can be suppressed, and ride comfort of the tire 1 can be improved. From such a viewpoint, the length L of the anisotropic sheet 9A in the tire radial direction is more preferably 30% to 50% of the cross-sectional height H of the tire 1.

The length of the region where the anisotropic sheet 9A overlaps the bead apex 8, that is, the distance d5 in the tire radial direction from the inner end 9A of the anisotropic sheet 9A to the outer end 8a of the bead apex 8 is preferably 10% to 90% of the length L in the tire radial direction of the anisotropic sheet 9A. By setting the distance d5 from the inner end 9A of the anisotropic piece 9A to the outer end 8a of the bead apex 8 to 10% or more of the length L of the anisotropic piece 9A, the steering stability of the tire 1 can be improved. By setting the distance d5 from the inner end 9A of the anisotropic sheet 9A to the outer end 8a of the bead apex 8 to 90% or less of the length L of the anisotropic sheet 9A, ride comfort of the tire 1 can be improved. From such a viewpoint, the distance d5 from the inner end 9A of the anisotropic sheet 9A to the outer end 8a of the bead apex 8 is more preferably 30% to 70% of the length L of the anisotropic sheet 9A.

The anisotropic sheet 9A of the present embodiment has a complex elastic modulus Ea in the tire circumferential direction at 70 ℃ that is greater than a complex elastic modulus Eb in the tire radial direction at 70 ℃. Since the anisotropic sheet 9A has a rigidity in the tire circumferential direction greater than that in the tire radial direction, it is possible to achieve both a steering stability performance in which the rigidity in the tire circumferential direction greatly contributes and a ride comfort performance in which the rigidity in the tire radial direction greatly contributes.

Here, the complex elastic moduli Ea and Eb of the anisotropic sheet 9A at 70 ℃ are values measured by a viscoelastic spectrometer manufactured by kyani corporation under the following conditions in accordance with the regulations of JIS-K6394.

Initial strain: 10 percent of

Amplitude of dynamic strain: plus or minus 1 percent

Frequency: 10Hz

Deformation mode: stretching

Measuring temperature: 70 deg.C

The anisotropic sheet 9A preferably has a complex elastic modulus Ea at 70 ℃ in the tire circumferential direction of 110 to 170% of a complex elastic modulus Eb at 70 ℃ in the tire radial direction. Since the difference between the tire circumferential direction and the tire radial direction is generated by setting the complex elastic modulus Ea of the anisotropic sheet 9A in the tire circumferential direction to 110% or more of the complex elastic modulus Eb of the tire radial direction, the steering stability performance and the riding comfort performance of the tire 1 can be both satisfied. The complex elastic modulus Ea in the tire circumferential direction of the anisotropic sheet 9A is 170% or less of the complex elastic modulus Eb in the tire radial direction, whereby excessive anisotropy can be suppressed. From such a viewpoint, the complex elastic modulus Ea of the anisotropic sheet 9A in the tire circumferential direction is more preferably 120% to 150% of the complex elastic modulus Eb in the tire radial direction.

The anisotropic sheet 9A of the present embodiment contains a rubber component. As the rubber component of the anisotropic sheet 9A, for example, isoprene rubber such as Isoprene Rubber (IR) and Natural Rubber (NR), and diene rubber such as styrene-butadiene rubber (SBR) and Butadiene Rubber (BR) are suitably used. The rubber component of the anisotropic sheet 9A may include, for example, styrene-isoprene-butadiene copolymer rubber (SIBR), styrene-isobutylene-styrene block copolymer (SIBS), Chloroprene Rubber (CR), acrylonitrile-butadiene rubber (NBR), hydrogenated nitrile rubber (HNBR), butyl rubber (IIR), ethylene propylene rubber, polynorbornene rubber, silicone rubber, salted polyethylene rubber, fluorine rubber (FKM), acrylate rubber (ACM), epichlorohydrin rubber, and the like.

The anisotropic sheet 9A of the present embodiment contains a biological nanomaterial. Here, the bio-nanomaterial refers to a bio-derived material having shape anisotropy and a diameter of a nanometer order, and for example, a fiber material derived from a plant or an animal is suitably used. The anisotropic sheet 9A may contain, for example, organic fibers such as polyvinyl alcohol (PVA) fibers, aramid fibers, polyester fibers, and nylon fibers, inorganic fibers such as glass fibers, carbon fibers, and metal fibers, polymer whiskers, metal whiskers, and whiskers such as ceramics.

The anisotropic sheet 9A preferably contains 1 to 40 parts by mass of a bio-nanomaterial per 100 parts by mass of the rubber component. By setting the bio-nanomaterial to 1 part by mass or more per 100 parts by mass of the rubber component, the anisotropic sheet 9A can be made anisotropic. By setting the bio-nanomaterial to 40 parts by mass or less per 100 parts by mass of the rubber component 100, a decrease in the breaking strength of the anisotropic sheet 9A can be suppressed.

The average diameter of the biological nano material is preferably 1-2000 nm. By setting the average diameter of the bio-nanomaterial to 1nm or more, the rigidity and processability of the anisotropic sheet 9A can be improved. By setting the average diameter of the bio-nanomaterial to 2000nm, an excessive increase in the rigidity of the anisotropic sheet 9A can be suppressed.

The average length of the biological nano material is preferably 0.1-10 mu m. By setting the average length of the bio-nanomaterial to 0.1 μm or more, the anisotropic sheet 9A can be made anisotropic. By setting the average length of the bio-nanomaterial to 10 μm or less, an excessive increase in the rigidity of the anisotropic sheet 9A can be suppressed.

The aspect ratio (average length/average diameter) of the biological nanomaterial is preferably 2 to 500. By setting the aspect ratio (average length/average diameter) of the bio nanomaterial to 2 or more, the anisotropic sheet 9A can be made anisotropic. By setting the aspect ratio (average length/average diameter) of the bio nanomaterial to 500 or less, the reduction in breaking strength of the anisotropic sheet 9A can be suppressed.

As the biological nanomaterial, for example, a fibrous material derived from living organisms such as nanocellulose, chitin nanofiber, chitosan nanofiber and the like is suitably used. Preferably the biological nanomaterial comprises nanocellulose. Such a bio-nanomaterial can improve workability and reduce manufacturing cost.

Examples of the nanocellulose include Cellulose Nanofibers (CNF) and Cellulose Nanocrystals (CNC). The nanocellulose preferably comprises Cellulose Nanofibers (CNF). Such nanocellulose can improve processability and reduce production cost.

The Cellulose Nanofibers (CNF) are preferably made from microfibrils of plant-derived cellulose or fibers constituting the microfibrils. The Cellulose Nanofibers (CNF) may include, for example, Bacterial Cellulose (BC), lignocellulose nanofibers (LCNF), nanofibers produced by an electrospinning method, and the like.

The bio-nanomaterial of the anisotropic sheet 9A of the present embodiment is oriented in the transfer direction, i.e., the process direction, when extruded using an extruder. Therefore, when the anisotropic sheet 9A is disposed on the carcass 6 so that the extrusion direction (process direction) is the tire circumferential direction, the bio-nanomaterial can be oriented in the tire circumferential direction. Such an anisotropic sheet 9A facilitates the complex elastic modulus Ea at 70 ℃ in the tire circumferential direction to be larger than the complex elastic modulus Eb at 70 ℃ in the tire radial direction.

While the above description has been made of a particularly preferred embodiment of the present invention, the present invention is not limited to the above-described embodiment, and can be modified into various embodiments.

Examples

A tire having a meridian section of the tire of fig. 1 was produced in a trial based on the specifications of table 1. Using the test tires, steering stability performance and ride comfort performance were evaluated. The common specification and test method of each test tire are as follows.

< common Specification >

Testing the vehicle: front wheel driven hybrid power passenger car

Tire size: 195/65R15

Internal pressure: 230kPa

< handling stability Performance >

1 test driver was seated on a test vehicle having a test tire mounted on all wheels, and the steering stability performance while running on the test course was evaluated by the driver's sense. The results are expressed by an index of 100 in comparative example 1, and the larger the value, the more excellent the steering stability.

< ride comfort >

1 test driver was seated on a test vehicle having a test tire mounted on all wheels, and ride comfort during running on a test runway was evaluated by the driver's senses. The results are expressed as an index with comparative example 1 being 100, and the larger the value, the more excellent the riding comfort.

The results of the test are shown in table 1.

TABLE 1

The results of the test confirm: the tires of the examples were able to achieve both steering stability performance and ride comfort performance at a high level, relative to the tires of the comparative examples.