Pneumatic radial tire for passenger car

Abstract

A passenger vehicle pneumatic radial tire is provided in which a cross-sectional width SW of the tire and an outer diameter OD of the tire satisfy a predetermined relationship, a carcass has a first tire width direction portion in which a carcass cord radial is configured and a second tire width direction portion in which the carcass cord extends angularly with respect to a tire circumferential direction, the second tire width direction portion is located in a tire width direction half portion located on an outer side when the tire is mounted on a vehicle, and the carcass cord of a carcass main portion in the second tire width direction portion and the belt cord extend in directions crossing each other when viewed from a tire radial outer side.

Description

Technical Field

[0001] This disclosure relates to an inflatable radial tire for passenger cars. Background Technology

[0002] As a type of pneumatic radial tire for passenger cars designed to improve fuel efficiency, the applicant has proposed a narrow-width, large-diameter pneumatic radial tire for passenger cars with a predetermined relationship between the tire's cross-sectional width SW and outer diameter OD (e.g., Patent Document 1). Furthermore, in this narrow-width, large-diameter pneumatic radial tire for passenger cars, for the purpose of weight reduction and further improvement of fuel efficiency, it has also been proposed to use only one inclined belt layer in which the belt cords are inclined relative to the tire circumference (see, for example, Patent Document 2).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: WO 2011 / 135774 A1

[0006] Patent Document 2: Japanese Patent Application Publication No. 2020-093674 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, when only one inclined belt layer is used, the rigidity of the belt cord in the extension direction will be high and the tread rubber will not be able to stretch in that direction, such as Figure 1 As illustrated, the shape of the ground contact pitch will deteriorate, which can lead to a decrease in tire driving performance. In particular, the fact that the tire has a small section width (SW) and that passenger car pneumatic radial tires such as those mentioned above are often used at high internal pressures also contribute to the deterioration of the ground contact pitch shape.

[0009] Therefore, the object of this disclosure is to provide a pneumatic radial tire for passenger cars that can reduce tire weight by having only one inclined belt layer, while also improving the shape of the contact patch to control the decline in tire driving performance.

[0010] Solution for solving the problem

[0011] The key points of this disclosure are as follows:

[0012] (1) A pneumatic radial tire for passenger vehicles, comprising

[0013] A pair of tire bead sections;

[0014] The carcass, comprising one or more carcass plies, said carcass plies being made of rubber-coated carcass cords; and

[0015] The belt section, located radially outward of the tire crown portion of the tire carcass, consists of only one inclined belt layer. This inclined belt layer is composed of belt ply layers, which are made of rubber-coated belt cords extending at an angle relative to the tire circumference.

[0016] The cross-sectional width SW of the tire is less than 165 (mm).

[0017] The ratio of the tire's cross-sectional width SW to its outer diameter OD is 0.26 or less, or the ratio of the tire's cross-sectional width SW (mm) to its outer diameter OD (mm) satisfies the following relationship:

[0018] OD(mm)≥-0.0187×SW(mm) 2 +9.15×SW(mm)-380(mm),

[0019] The tire carcass has a first tire width direction portion with radially arranged carcass cords and a second tire width direction portion with the carcass cords extending at an angle relative to the tire circumference.

[0020] The tire carcass has a main body portion extending radially inward from the bead portion to the belt portion.

[0021] The second tire width direction portion is located in the outer half of the tire width direction when the tire is mounted on the vehicle, and

[0022] When viewed from the radial outer side of the tire, the carcass cords and belt cords of the carcass body portion in the second tire width direction extend in directions that intersect each other.

[0023] Here, "extending in directions that intersect each other" refers not only to the case where the cords intersect when viewed from the radial outer side of the tire, but also to the case where the cords intersect when the carcass cords or the belt cords extend.

[0024] As used herein, the term "rim" refers to a standard rim of applicable dimensions as described or potentially described in the industrial standards effective in the region where the tire is produced and used (such as the JATMA Yearbook of Japan's JATMA (Japan Automobile Tire Manufacturers Association), the standards manual of ETRTO (European Tire and Rim Technology Organization), and the yearbook of TRA (Tire and Rim Association) in the United States) (measured rims in ETRTO's standards manual and designed rims in TRA's yearbook). (That is, the "rim" in "wheel" above includes both current dimensions and dimensions to be described in the aforementioned industrial standards in the future. An example of a "dimensional to be described in the future" could be a dimension listed as "future development" in the 2013 edition of ETRTO). However, for dimensions not listed in these industrial standards, the term "rim" refers to a rim whose width corresponds to the width of the tire's bead.

[0025] Furthermore, the term "specified internal pressure" refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity of a single wheel for the applicable size and ply rating, as described in the aforementioned JATMA Yearbook and other industry standards. For sizes not listed in the aforementioned industry standards, the term "specified internal pressure" refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity specified for each vehicle with the tire mounted.

[0026] In addition, the term "maximum load" refers to the load corresponding to the aforementioned maximum load capacity.

[0027] The effects of the invention

[0028] According to this disclosure, a pneumatic radial tire for passenger cars can be provided that can reduce tire weight by having only one inclined belt layer, while improving the shape of the contact patch to control the decline in tire driving performance. Attached Figure Description

[0029] In the attached image:

[0030] Figure 1 It is a schematic diagram illustrating the shape of the contact patch when the tire has only one sloping belt layer;

[0031] Figure 2 This is a schematic diagram illustrating the cross-sectional width SW and outer diameter OD of a tire;

[0032] Figure 3 This is a cross-sectional view in the tire width direction of an inflatable radial tire for passenger cars according to one embodiment of the present disclosure;

[0033] Figure 4 It is a schematic diagram illustrating the structure of the carcass, belt section, and cover layer;

[0034] Figure 5It is a schematic diagram illustrating another fetal structure;

[0035] Figure 6 It is a schematic diagram illustrating the improvement in the shape of the ground plane;

[0036] Figure 7 This is a diagram that schematically illustrates another example of the structure of the carcass, belt section, and cover layer;

[0037] Figure 8 This is a diagram illustrating the configuration of RFID; and

[0038] Figure 9 This is a cross-sectional view of the tire width of a modified pneumatic radial tire for passenger cars. Detailed Implementation

[0039] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0040] Figure 2 This is a schematic diagram showing the cross-sectional width SW and outer diameter OD of a tire.

[0041] According to one embodiment of this disclosure, a pneumatic radial tire for passenger vehicles (hereinafter referred to as "tire") has a tire section width SW of less than 165 mm, and the ratio of the tire section width SW to the outer diameter OD, SW / OD, is 0.26 or less, thus having a narrow width and large diameter shape. By making the tire section width SW narrower relative to the tire outer diameter OD, air resistance can be reduced, and by making the tire outer diameter OD larger relative to the tire section width SW, deformation of the tread rubber in the area near the tire contact patch is controlled and rolling resistance can be reduced. By these means, the fuel efficiency of the tire can be improved. The ratio SW / OD is preferably 0.25 or less, and more preferably 0.24 or less.

[0042] The above ratio is preferably satisfied when the tire internal pressure is 200 kPa or higher, more preferably when the tire internal pressure is 220 kPa or higher, and even more preferably when the tire internal pressure is 280 kPa or higher. This is because rolling resistance can be reduced. On the other hand, it is preferable to satisfy the above ratio when the tire internal pressure is 350 kPa or lower. This is because ride comfort can be improved.

[0043] Here, the tire's section width SW is preferably 105 to 145 mm, and more preferably 115 to 135 mm.

[0044] Furthermore, when the tire's cross-sectional width SW and outer diameter OD satisfy the above ratios, the tire's aspect ratio is preferably 45 to 70, and more preferably 45 to 65.

[0045] There are no specific restrictions on the exact tire size, but it can be, for example, 105 / 50R16, 115 / 50R17, 125 / 55R20, 125 / 60R18, 125 / 65R19, 135 / 45R21, 135 / 55R20, 135 / 60R17, 135 / 60R18, 135 / 60R19, 135 / 65R19, 145 / 45R21, or 145 / 55R2. Any size from 0, 145 / 60R16, 145 / 60R17, 145 / 60R18, 145 / 60R19, 145 / 65R19, 155 / 45R18, 155 / 45R21, 155 / 55R18, 155 / 55R19, 155 / 55R21, 155 / 60R17, 155 / 65R18, 155 / 70R17, and 155 / 70R19.

[0046] Alternatively, the tire's section width SW is less than 165 mm, and the tire's section width SW (mm) and outer diameter OD (mm) satisfy the following relationship:

[0047] OD(mm)≥-0.0187×SW(mm)2+9.15×SW(mm)-380,

[0048] Therefore, tires have a narrow width and a large diameter.

[0049] By satisfying the above relationship expression, air resistance and rolling resistance can be reduced, thereby improving tire fuel efficiency.

[0050] In the third aspect, regarding the tire's cross-sectional width SW and outer diameter OD, when the above relationship expression is satisfied, the ratio SW / OD is preferably 0.26 or less, more preferably 0.25 or less, and even more preferably 0.24 or less. This is because it can further improve the tire's fuel efficiency.

[0051] The above relationship and ratio are preferably satisfied when the tire internal pressure is 200 kPa or higher, more preferably when the tire internal pressure is 220 kPa or higher, and even more preferably when the tire internal pressure is 280 kPa or higher. This is because rolling resistance can be reduced. On the other hand, it is preferable that the above relationship and ratio are satisfied when the tire internal pressure is 350 kPa or lower. This is because ride comfort can be improved.

[0052] Here, the tire's section width SW is preferably 105 to 145 mm, and more preferably 115 to 135 mm.

[0053] Furthermore, when the tire's cross-sectional width SW and outer diameter OD satisfy the above relationship, the tire's aspect ratio is preferably 45 to 70, and more preferably 45 to 65.

[0054] There are no specific restrictions on the exact tire size, but it can be, for example, 105 / 50R16, 115 / 50R17, 125 / 55R20, 125 / 60R18, 125 / 65R19, 135 / 45R21, 135 / 55R20, 135 / 60R17, 135 / 60R18, 135 / 60R19, 135 / 65R19, 145 / 45R21, or 145 / 55R2. Any size from 0, 145 / 60R16, 145 / 60R17, 145 / 60R18, 145 / 60R19, 145 / 65R19, 155 / 45R18, 155 / 45R21, 155 / 55R18, 155 / 55R19, 155 / 55R21, 155 / 60R17, 155 / 65R18, 155 / 70R17, and 155 / 70R19.

[0055] The tire used in this embodiment is a pneumatic radial tire for passenger cars. This tire is particularly suitable for use as a tire for personal motor vehicles.

[0056] Figure 3 This is a cross-sectional view in the tire width direction of an inflatable radial tire for passenger cars according to one embodiment of the present disclosure. Figure 3 The diagram illustrates a cross-sectional view of a tire under baseline conditions: the tire is mounted on a rim, inflated to a specified internal pressure, and unloaded. (See diagram for reference.) Figure 3 As shown, the tire 1 includes a carcass 3, which is composed of one or more carcass plies, each made of rubber-coated carcass cords. Furthermore, the tire 1 includes a belt portion 4 and a tread 5 sequentially on the radially outer side of the crown portion of the carcass 3. The belt portion 4 consists of only one inclined belt layer, which is composed of a belt ply made of rubber-coated belt cords extending at an angle relative to the tire circumference.

[0057] In this example, the bead core 2a is embedded in each bead portion 2. In this disclosure, the cross-sectional shape and material of the bead core 2a are not particularly limited, and it can be manufactured with a configuration commonly used in pneumatic radial tires for passenger cars. In this disclosure, the bead core 2a can be divided into multiple smaller bead cores. Alternatively, in this disclosure, the bead portion 2 can be configured without a bead core 2a.

[0058] In the example shown, tire 1 has a bead filler 2b with a generally triangular cross-section located radially outside the bead core 2a. The cross-sectional shape of the bead filler 2b is not limited to this example, nor is the material limited to this example. Alternatively, the tire can be made lighter by omitting the bead filler 2b.

[0059] In this embodiment, the tire 1 may also have a rim protection portion. Furthermore, in this embodiment, the bead portion 2 may also have additional components, such as rubber layers or cord layers for reinforcement purposes. These additional components can be disposed in various positions relative to the tire carcass 3 and the bead filler 2b.

[0060] exist Figure 3 In the example shown, the carcass 3 is composed of a single carcass ply. On the other hand, in this disclosure, the number of carcass plies is not particularly limited and can be two or more. Furthermore, as... Figure 4 As shown, the tire carcass 3 has a first tire width direction portion 301 and a second tire width direction portion 302. In the first tire width direction portion 301, the tire carcass cords are arranged radially. In the second tire width direction portion 302, the tire carcass cords extend at an angle relative to the tire circumference. The second tire width direction portion 302 is located in the outer half of the tire width direction when the tire is mounted on a vehicle (in the example shown, only a portion of this half). Figure 3In the example shown, the tire carcass 3 has a carcass body portion 3a extending annularly between the pair of bead portions 2 and a carcass fold-back portion 3b folded back from the carcass body portion 3a around the bead core 2a. The carcass body portion 3a extends from the bead portion 2 to the radially inner side of the tire of the belt portion 4. On the other hand, in this disclosure, the carcass fold-back portion 3b may be wound around the bead core 2a or may be sandwiched between multiple separate small bead cores. The end portion 3c of the carcass fold-back portion 3b is located radially outer of the tire at the radially outer end of the bead filler 2b and radially inner of the tire at the tire's maximum width position. This allows for tire weight reduction while maintaining the rigidity of the sidewall portion. On the other hand, in this disclosure, the end portion 3c of the carcass fold-back portion 3b may be located radially inner of the tire at the radially outer end of the bead filler 2b, or it may be located radially outer of the tire at the tire's maximum width position. Alternatively, it can be an encapsulated structure, wherein the end 3c of the carcass fold-back portion 3b is located inside the tire width direction of the end of the belt portion 4 (e.g., the end of the belt layer 4b), such that the end 3c of the carcass fold-back portion 3b is located radially between the carcass body portion 2a and the belt portion 4. Furthermore, when the carcass 3 is composed of multiple carcass plies, the position of the end 3c of the carcass fold-back portion 3b (e.g., its position radially in the tire) can be the same or different among the carcass plies. There is no particular limitation on the number of carcass cords per unit width in the carcass 3, but for example, it can be in the range of 20 to 60 cords / 50 mm. Furthermore, the carcass cords can adopt various structures. For example, radially in the tire, the position of the maximum carcass width can be closer to the bead portion 2 or closer to the tread portion 5. For example, the position of the maximum carcass width can be set from the bead baseline to the radially outer side of the tire, within the range of 50% to 90% of the tire's cross-sectional height. The aforementioned "radial configuration" refers to a configuration in which the tire carcass cords extend at an angle of 85° or greater, and preferably 90°, relative to the tire circumference. For example... Figure 4 As shown, due to the folding of the tire carcass, the inclination direction of the belt cords in the second tire width direction portion 302 is opposite between the tire carcass main body portion 3a and the tire carcass folding portion 3b, as illustrated. Figure 3 As shown, the tire body 3 can be configured to span the pair of bead portions 2 in a ring. Alternatively, as... Figure 5As schematically shown, the tire carcass 3 can be configured to have: a first tire carcass 351 extending from the bead portion 2 in the outer half of the tire width direction when the tire is mounted on the vehicle to the radially inner side of the tire belt portion; and a second tire carcass 352 extending from the bead portion 2 in the inner half of the tire width direction when the tire is mounted on the vehicle to the radially inner side of the tire belt portion. Furthermore, to improve the rigidity of the tire on the outer side when mounted on the vehicle, as shown, the second tire carcass 352 can have a radial extension 352a extending along the first tire carcass 351 from the radially outer side of the tire to the radially inner side of the tire and terminating in the radially inner side of the bead portion in the outer half of the tire width direction when the tire is mounted on the vehicle. Alternatively, to reduce tire weight, the second tire carcass 352 can be configured without the radial extension 352a.

[0061] In the tire of this embodiment, preferably, the tire has only one inclined belt layer, which is composed of a belt ply made of rubber-coated belt cords extending at an angle relative to the tire circumference, and the width of the belt layer in the tire width direction is 90% to 115% of the ground contact width, particularly preferably 100% to 105% of the ground contact width. It should be noted that "ground contact width" refers to the distance between the ground contact ends E in the tire width direction. "Ground contact ends" refers to the two ends of the tire contact surface in the tire width direction when the tire is mounted on a rim, inflated with a specified internal pressure, and loaded with maximum load.

[0062] In this embodiment, the belt cord of the belt layer is most preferably a metal cord, particularly a steel cord, but non-metallic cords such as organic fiber cords (e.g., Kevlar (registered trademark)) can also be used. Steel cords are primarily made of steel and may also contain various trace elements such as carbon, manganese, silicon, phosphorus, sulfur, copper, and chromium. In this embodiment, the belt cord of the belt layer can be a monofilament cord, a cord made of multiple parallel filaments, or a cord made of multiple filaments twisted together. Various twisting structures can be used, and the cross-sectional structure, twist pitch, twist direction, and distance between adjacent filaments can also be varied. Furthermore, cords made of twisted filaments of different materials can be used, and there are no particular limitations on the cross-sectional structure; various twisting structures such as single twist, multi-twist, and multi-twist can be used.

[0063] In this embodiment, the inclination angle of the belt cords in the belt layer relative to the tire circumference is preferably 10° or greater. In this embodiment, the inclination angle of the belt cords in the belt layer relative to the tire circumference is preferably a higher angle, specifically 20° or greater, particularly in the range of 20° to 45° relative to the tire circumference. This is because by making the inclination angle 20° or greater, the rigidity in the tire width direction can be increased, and handling stability performance, especially during cornering, can be improved. Furthermore, this is because rolling resistance is reduced by decreasing the shear deformation of the interlayer rubber.

[0064] In this embodiment, as Figure 4 As shown, when viewed from the radial outer side of the tire, the carcass cords and belt cords of the carcass body portion 3a in the second tire width direction portion 302 extend in directions that intersect each other. The inclination angle of the carcass cords in the carcass body portion 3a in the second tire width direction portion 302 relative to the tire circumference is greater than the inclination angle of the belt cords relative to the tire circumference. The inclination angle of the carcass cords in the carcass body portion 3a in the second tire width direction portion 302 relative to the tire circumference is preferably 70° to 88°, more preferably 76° to 84°.

[0065] In the example shown, the end of the belt portion 4 is located within the first tire width direction portion 301. In the example shown, the tire width direction width of the cover layer 8 is smaller than the tire width direction width of the belt portion 4.

[0066] Preferably, the position of the inner end of the second tire width direction portion 302 in the tire width direction is 10% to 40% of the tire width direction width of the belt portion, spaced outward from the end of the belt portion 4 in the tire width direction.

[0067] In the example shown, the tread rubber constituting the tread 5 is composed of a single layer. However, in this embodiment, the tread rubber constituting the tread 5 can be formed by laminating multiple rubber layers in the radial direction of the tire. These multiple rubber layers can have different loss tangents, moduli, hardness, glass transition temperatures, materials, etc. Furthermore, the thickness ratio of the multiple rubber layers in the radial direction of the tire can vary in the tire width direction, and the bottom of the circumferential main groove, etc., can also be made of rubber layers different from the surrounding areas. Furthermore, the tread rubber constituting the tread 5 can be formed from multiple rubber layers that are different in the tire width direction. These multiple rubber layers can have different loss tangents, moduli, hardness, glass transition temperatures, materials, etc. Furthermore, the width ratio of the multiple rubber layers in the tire width direction can vary in the radial direction of the tire, and only limited areas (such as only the area near the circumferential main groove, only the area near the contact patch, only the shoulder land area, or only the central land area, etc.) can have rubber layers different from the surrounding areas.

[0068] The tire 1 of this embodiment has a liner 7 on its inner surface 6 (hereinafter referred to as the tire inner surface 6), and the thickness of the liner 7 is preferably about 1.5 mm to 2.8 mm. This is because it can effectively reduce in-vehicle noise in the 80 to 100 Hz range. The air permeability coefficient of the rubber composition constituting the liner 7 is preferably 1.0 × 10⁻⁶. -14 cc·cm / (cm 2 (·s·cmHg) or greater and 6.5×10 -10 cc·cm / (cm 2 (·s·cmHg) or less.

[0069] like Figure 3 As shown, the tire has one or more (one in the example shown) cover layers 8 on the radial outer side of the belt portion 4.

[0070] The cover layer 8 is composed of strip-shaped members, which are made of rubber-coated cords arranged in generally parallel directions and spirally wound around the tire circumference. In the example shown, the width of the cover layer 8 in the tire width direction is smaller than the width of the belt portion 4 in the tire width direction. As for the cords of the cover layer 8, organic fiber cords can be used, for example.

[0071] The following describes the effects of the pneumatic radial tire for passenger cars according to this embodiment.

[0072] The passenger car pneumatic radial tire in this embodiment is a narrow-width, large-diameter tire with a cross-section width SW of less than 165 mm, which satisfies the above-mentioned relationship between the tire's cross-section width SW and outer diameter. According to this tire, air resistance can be significantly reduced, and rolling resistance can also be reduced, thereby improving the tire's fuel efficiency.

[0073] In this embodiment, the tire has a belt portion consisting of only one inclined belt layer, so the tread rubber is unlikely to be in the inclined direction of the belt cord ( Figure 4 The tire is stretched in the direction of the upper right and lower left of the tire. Relatedly, the tire of this embodiment also has a first tire width direction portion 301 and a second tire width direction portion 302. In the first tire width direction portion 301, the carcass cords are arranged radially. In the second tire width direction portion 302, the carcass cords extend at an angle relative to the tire circumference, and when viewed from the radial outer side of the tire, the carcass cords of the carcass body portion 3a in the second tire width direction portion 302 extend in directions intersecting each other with the belt cords. For this reason, the carcass cords of the carcass body portion 3a in the second tire width direction portion 302 are subjected to a force attempting to restore the radial arrangement, which can promote the tread rubber to stretch in the direction of this force (…). Figure 4 The stretching is done in the upper right and lower left directions. This method further reduces the difficulty of stretching the tread rubber in the inclined direction of the belt cords, such as... Figure 6 As illustrated schematically, the shape of the contact surface has been improved, thereby improving handling stability and other driving performance.

[0074] Preferably, the inclination angle of the carcass cords in the carcass main body 3a of the second tire width direction portion 302 relative to the tire circumference is greater than the inclination angle of the belt cords relative to the tire circumference. This is because by making the inclination angle of the carcass cords in the carcass main body 3a of the second tire width direction portion 302 relative to the tire circumference greater than the inclination angle of the belt cords relative to the tire circumference, both load-bearing rigidity and lateral rigidity can be achieved, as well as torsional deformation of the contact patch shape can be corrected.

[0075] Furthermore, it is preferable that the inclination angle of the carcass cords of the carcass body portion 3a in the second tire width direction portion 302 relative to the tire circumference is 70° to 88°. This is because by setting the inclination angle to 70° or greater, both torsional deformation and rigidity can be achieved simultaneously, while setting the inclination angle to 88° or less can generate sufficient restoring force against torsion. For the same reason, it is even more preferable that the inclination angle is 76° to 84°.

[0076] Furthermore, preferably, the position of the inner end of the second tire width direction portion 302 in the tire width direction is spaced 10% to 40% of the tire width direction width of the belt portion 4 from the end of the belt portion 4 in the tire width direction (the end in the same tire width direction half) outward in the tire width direction. This is because, by setting the interval to 10% or more, the shape correction effect of the contact surface of the entire tire width direction half located on the inside when the tire is mounted on the vehicle can be obtained, while by setting the interval to 40% or less, both torsional deformation and rigidity can be achieved. For the same reason, it is further preferred that the position of the inner end of the second tire width direction portion 302 in the tire width direction is spaced 20% to 30% of the tire width direction width of the belt portion 4 from the end of the belt portion 4 in the tire width direction outward in the tire width direction.

[0077] like Figure 7 As shown, preferably, the tire carcass also has a third tire width direction portion 303, which is different from the second tire width direction portion 302. In the third tire width direction portion, the carcass cords extend at an angle relative to the tire circumference. The third tire width direction portion 303 is located in the inner half of the tire width direction portion when the tire is mounted on the vehicle, and when viewed from the radially outer side of the tire, the carcass cords and belt cords of the tire body portion 3a in the third tire width direction portion 303 extend in directions that intersect each other. Even in the inner half of the tire width direction portion when the tire is mounted on the vehicle, the force in the third tire width direction portion 303 attempting to restore the radial configuration of the carcass cords in the tire body portion 3a also has a promoting effect on the tread rubber in the direction of the force ( Figure 7 This improves the stretching effect in the upper right and lower left directions (within the tire), and further reduces the difficulty of stretching the tread rubber in the inclined direction of the belt cords. Therefore, the shape of the contact patch can be further improved to further enhance driving performance.

[0078] It should be noted that pneumatic radial tires for passenger cars can be mounted on the left wheel of the vehicle, and when viewed radially outward from the tire, the belt cords extend from the lower left to the upper right. Figure 7 Alternatively, it can be installed on the right wheel of the vehicle, and when viewed from the radially outer side of the tire, the belt cord can extend from the lower right to the upper left.

[0079] Furthermore, the tire body 3 can be circumferentially spanned between the pair of bead portions 2. Alternatively, the tire body 3 can have a first tire body 351 and a second tire body 352, wherein the first tire body 351 extends from the bead portion 2 in the outer half of the tire width direction when the tire is mounted on the vehicle to the radially inner side of the tire in the belt portion 4, and the second tire body 352 extends from the bead portion 2 in the inner half of the tire width direction when the tire is mounted on the vehicle to the radially inner side of the tire in the belt portion 4.

[0080] In addition, such as Figure 9 As shown, the radial distance between a straight line m1 passing through a point on the tread surface at the tire equator and parallel to the tire width direction and a straight line m2 passing through the ground contact point E and parallel to the tire width direction is defined as the drop height L. CR Furthermore, when the tire tread width is defined as TW, the preferred ratio is L. CR / TW is greater than 0.045. This allows for a relatively rounded tread shape, and consequently, a more rounded contact patch shape, with the contact patch length in the shoulder being shorter than that in the center. This prevents the contact patch shape from becoming too narrow as the camber angle changes, and further controls the degradation of the contact patch shape. "Contact point" refers to the two ends of the tire's contact patch (the part in contact with the road surface) when the tire is mounted on a rim, inflated to the specified internal pressure, and under maximum load. "Tread width" refers to the distance between the contact points of the tire when the tire is mounted on a rim, inflated to the specified internal pressure, and unloaded.

[0081] <Tire and Rim Components>

[0082] Here, a tire and rim assembly is formed by mounting the aforementioned pneumatic radial tire for passenger cars onto a rim. According to this tire and rim assembly, the same effects as those described for the aforementioned pneumatic radial tire for passenger cars can be obtained. In this case, the internal pressure of the tire and rim assembly is preferably 200 kPa or greater, more preferably 220 kPa or greater, and even more preferably 280 kPa or greater. This is because increasing the internal pressure further reduces rolling resistance. On the other hand, the internal pressure of the tire and rim assembly is preferably 350 kPa or less, as this improves ride comfort.

[0083] <How to Use Pneumatic Radial Tires for Passenger Cars>

[0084] The method of using pneumatic radial tires for passenger cars employs the aforementioned method. According to this method, the same effects as those described above can be obtained. Preferably, the pneumatic radial tire is used with an internal pressure of 200 kPa or greater, even more preferably with an internal pressure of 220 kPa or greater, and even more preferably with an internal pressure of 280 kPa or greater. This is because increasing the internal pressure further reduces rolling resistance. On the other hand, it is preferable to use the pneumatic radial tire with an internal pressure of 350 kPa or less, as this improves ride comfort.

[0085] <Example of a communication device>

[0086] like Figure 8 As shown, the tire may include an RF tag as a communication device 500. The RF tag has an IC chip and an antenna. For example, the RF tag can be configured by sandwiching it between multiple components of the same or different types constituting the tire. In this way, it is easier to attach the RF tag during tire production and the productivity of tires with RF tags can be improved. In this example, the RF tag can be configured, for example, between the bead filler and other components adjacent to the bead filler. The RF tag can be embedded in any component constituting the tire. In this way, the load on the RF tag can be reduced compared to configuring the RF tag by sandwiching it between multiple components constituting the tire, thereby improving the durability of the RF tag. In this example, the RF tag can be embedded in rubber components such as tread rubber and sidewall rubber. Preferably, the RF tag is not configured at a location that serves as a boundary between components with different levels of rigidity in the peripheral length direction, which is the direction along the outer surface of the tire when viewed in a cross-section in the tire width direction. In this way, the RF tag is not configured at a location where skew is likely to concentrate based on rigidity differences. This reduces the load on the RF tag, thereby improving the durability of the RF tag. In this example, it is preferable that the RF tag is not positioned at a location that serves as, for example, the boundary between the edge of the tire carcass and a component adjacent to that edge (e.g., sidewall rubber, etc.) when viewed in a cross-section along the tire's width. The number of RF tags is not limited. A tire may have only one RF tag, or it may have two or more RF tags. Here, the RF tag is illustrated as an example of a communication device, but communication devices other than RF tags may also be used.

[0087] The RF tag can be positioned, for example, within the tread of the tire. This prevents damage from tire sidecuts. The RF tag can also be positioned, for example, at the center of the tread in the tire width direction. The center of the tread is a location where twisting is less likely to concentrate. This reduces the load applied to the RF tag, thereby improving its durability. It also prevents discrepancies in communication between the RF tag and the outer edges of the tire in the tire width direction. In this example, in the tire width direction, the RF tag can be positioned, for example, within half the tread width centered on the tire's equatorial plane. In the tire width direction, the RF tag can also be positioned, for example, at the tread end. If a reader for communication with the RF tag is pre-defined, the RF tag can be positioned, for example, at the tread end on the side closest to the reader. In this example, in the tire width direction, the RF tag can be positioned, for example, within one-quarter of the tread width with the tread end as the outer edge.

[0088] RF tags can be configured on the inner side of the tire carcass, for example, including one or more carcass plies spanning between the bead portions. In this way, the RF tag becomes less likely to be damaged by external impacts to the tire, or by damage such as sidecuts or nail punctures. As an example, the RF tag can be configured to be in close contact with the surface of the carcass facing the tire cavity. As another example, when there is another component on the inner side of the carcass, the RF tag can be configured between the carcass and that other component located on the inner side of the carcass. This other component on the inner side of the carcass is, for example, an inner liner forming the inner surface of the tire. As another example, the RF tag can be attached to the inner surface of the tire facing the tire cavity. By attaching the RF tag to the inner surface of the tire, it is easy to attach the RF tag to the tire, and also easy to inspect and replace the RF tag. In other words, the convenience of attaching and maintaining the RF tag can be improved. Furthermore, by attaching the RF tag to the inner surface of the tire, compared to a structure where the RF tag is embedded inside the tire, it is possible to prevent the RF tag from becoming the source of tire failure. In addition, when the tire carcass has multiple carcass plies and there are multiple overlapping carcass plies, RF tags can be configured between the overlapping carcass plies.

[0089] For example, the RF tag can be disposed radially outside the belt portion in the tire tread, the belt portion consisting of only one belt ply. As an example, the RF tag can be configured to be in close contact with the belt portion radially outside the tire. Alternatively, as another example, when a reinforcing belt layer is provided, the RF tag can be configured to be in close contact with the reinforcing belt layer radially outside the tire. Furthermore, as yet another example, the RF tag can be embedded in the tread rubber radially outside the belt portion. By arranging the RF tag on the outside of the belt portion in the tire tread, communication between the tire radially outside and the RF tag is less likely to be interfered with by the belt portion. Therefore, communication between the tire radially outside and the RF tag can be improved. Furthermore, the RF tag can be disposed radially inside the belt portion in the tire tread, for example. In this way, the radially outside of the RF tag is covered by the belt portion, thus making the RF tag less likely to be damaged by impacts from the tread surface or by nails. As an example, an RF tag can be configured between the belt section and the tire carcass located radially inside the belt section.

[0090] RF tags can be configured at locations such as the sidewall or bead portion of the tire. For example, the RF tag can be configured on the sidewall or bead portion, for instance, near a reader that can communicate with the RF tag. This improves communication between the RF tag and the reader. As an example, the RF tag can be configured between the tire carcass and the sidewall rubber, or between the tread rubber and the sidewall rubber. The RF tag can be configured radially between, for example, the tire's maximum width position and the tread surface position. With this configuration, communication with the RF tag from the tire's radially outer side is improved compared to a configuration where the RF tag is configured radially inside the tire at the tire's maximum width position. The RF tag can be configured radially inside the tire at, for example, the tire's maximum width position. With this configuration, the RF tag is configured near the bead portion, which has high rigidity. This reduces the load applied to the RF tag, thereby improving its durability. As an example, the RF tag can be configured radially or in the tire width direction near the bead core. Misalignment is less likely to concentrate near the bead core, which reduces the load on the RF tag, thereby improving its durability. Specifically, it is preferable that the RF tag is disposed radially inside the tire at the tire's maximum width location and radially outside the tire's bead core at the bead portion. This configuration improves the durability of the RF tag, and communication between the RF tag and the reader is less likely to be interfered with by the bead core, thus improving the RF tag's communication performance. Furthermore, when the sidewall rubber is composed of multiple identical or different types of rubber components that are radially adjacent to each other, the RF tag can be configured to be sandwiched between the multiple rubber components constituting the sidewall rubber. The RF tag can be disposed, for example, on the outer surface of the sidewall rubber.

[0091] The RF tag can be configured, for example, to be sandwiched between a component of the bead filler and an adjacent filler. According to this configuration, the RF tag can be placed in a location where strain is unlikely to concentrate due to the disposal of the bead filler. This reduces the load applied to the RF tag, thereby improving its durability. The RF tag can also be configured, for example, between the bead filler and the tire carcass. The portion of the tire carcass that sandwiches the RF tag between the carcass and the bead filler can be located on the outer side of the tire width relative to the bead filler, or on the inner side of the tire width relative to the bead filler. If the portion of the tire carcass that sandwiches the RF tag between the carcass and the bead filler is located on the outer side of the tire width relative to the bead filler, the load applied to the RF tag due to impacts or damage from the outer side of the tire width can be reduced even further, thereby improving the RF tag's durability. Furthermore, the bead filler can have a portion adjacent to the sidewall rubber. In this case, the RF tag can be configured to be sandwiched between the bead filler and the sidewall rubber. Additionally, the bead filler can also have a portion adjacent to the rubber bead wrapping. In this case, the RF tag can be configured to be sandwiched between the bead filler and the rubber bead wrapping.

[0092] The RF tag can be configured, for example, sandwiched between the rubber bead wrap and the sidewall rubber. With this configuration, the RF tag can be placed in a location where strain is less likely to concentrate due to the placement of the rubber bead wrap. This reduces the load applied to the RF tag, thereby improving its durability. The RF tag can also be configured, for example, sandwiched between the rubber bead wrap and the tire carcass. With this configuration, the load applied to the RF tag due to impacts and damage from the rim can be reduced. Therefore, the durability of the RF tag can be improved.

[0093] The RF tag can be configured, for example, to be sandwiched between a steel bead wrap and another component adjacent to the steel bead wrap on the outer or inner side of the steel bead wrap in the tire width direction. With this configuration, the position of the RF tag is less likely to change when the tire deforms. This reduces the load applied to the RF tag when the tire deforms, thereby improving the durability of the RF tag. The other component adjacent to the steel bead wrap on the inner or outer side in the tire width direction can be a rubber component, such as a rubber bead wrap. Alternatively, the other component adjacent to the steel bead wrap on the inner or outer side in the tire width direction can be the tire carcass.

[0094] A belt reinforcement layer can be provided on the radially outer side of the belt portion of the tire. For example, the belt reinforcement layer can be formed by continuously spirally winding polyethylene terephthalate cords around the tire in the circumferential direction. (The last sentence appears to be incomplete and possibly refers to a specific method or technique.) -2 The cord is manufactured by applying an adhesive under a tension of N / tex or higher, and the elastic modulus under a load of 29.4 N measured at 160°C can be 2.5 mN / dtex% or higher. Furthermore, the belt reinforcement layer can be configured to cover the entire belt section, or it can be configured to cover only both ends of the belt section. Additionally, the winding density per unit width of the belt reinforcement layer can vary depending on its position in the width direction. According to this construction, road noise and flat spots can be reduced without compromising high-speed durability.

[0095] Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. For example, in the above examples, we have shown a case with a single cover layer, but in order to make the tire lighter, a construction without a cover layer is also possible.

[0096] [Contribution to the UN-led Sustainable Development Goals (SDGs)]

[0097] The SDGs were proposed to achieve a sustainable society. One implementation of this disclosure is considered a technology that can contribute to "No. 12 - Ensuring Sustainable Consumption and Production Patterns" and "No. 13 - Climate Change and Specific Countermeasures".

[0098] List of reference numerals

[0099] 1. Pneumatic radial tires for passenger cars (tires)

[0100] 2nd tire bead

[0101] 2a tire bead core

[0102] 2b Bead filler

[0103] 3. Fetal body

[0104] 301 First tire width direction section

[0105] 302 Second tire width direction section

[0106] 303 Third tire width direction section

[0107] 4. Belt section

[0108] 5. Tread

[0109] 6. Inner surface of the tire

[0110] 7 Lining

[0111] 8. Cap layer

[0112] 500 communication device

[0113] CL tire equatorial plane

Claims

1. A pneumatic radial tire for passenger vehicles, comprising: A pair of tire bead sections; The carcass, comprising one or more carcass plies, said carcass plies being made of rubber-coated carcass cords; and The belt section, located radially outward of the tire crown portion of the tire carcass, consists of only one inclined belt layer. This inclined belt layer is composed of belt ply layers, which are made of rubber-coated belt cords extending at an angle relative to the tire circumference. The cross-sectional width SW of the tire is less than 165 (mm). The ratio of the tire's cross-sectional width SW to its outer diameter OD is 0.26 or less, or the ratio of the tire's cross-sectional width SW (mm) to its outer diameter OD (mm) satisfies the following relationship: OD (mm) ≥ -0.0187 × SW (mm) 2 +9.15×SW (mm)-380 (mm), The tire carcass has a first tire width direction portion and a second tire width direction portion. In the first tire width direction portion, the tire carcass cords are arranged radially, and in the second tire width direction portion, the tire carcass cords extend at an angle relative to the tire circumference. The tire carcass has a main body portion extending radially inward from the bead portion to the belt portion. The second tire width direction portion is located in the outer half of the tire width direction when the tire is mounted on the vehicle. When viewed from the radial outer side of the tire, the carcass cords and belt cords of the body portion of the second tire width direction extend in directions that intersect each other, and The position of the inner end of the second tire width direction portion is 20% to 30% of the tire width direction width of the belt portion, from the end of the belt portion in the tire width direction to the outer side in the tire width direction.

2. The pneumatic radial tire for passenger vehicles according to claim 1, wherein, The inclination angle of the tire carcass cords in the tire body portion of the second tire width direction relative to the tire circumference is greater than the inclination angle of the belt cords relative to the tire circumference.

3. The pneumatic radial tire for passenger vehicles according to claim 1, wherein, The inclination angle of the tire carcass cords in the tire body portion of the second tire width direction relative to the tire circumference is 70° to 88°.

4. The pneumatic radial tire for passenger vehicles according to claim 2, wherein, The inclination angle of the tire carcass cords in the tire body portion of the second tire width direction relative to the tire circumference is 70° to 88°.

5. The pneumatic radial tire for passenger cars according to any one of claims 1 to 4, wherein, The pneumatic radial tire for passenger cars is installed on the left wheel of the vehicle. When viewed from the radial outer side of the tire, the belt cords extend from the lower left to the upper right. The tire carcass also has a third tire width direction portion, which is different from the second tire width direction portion, in which the tire carcass cords extend at an angle relative to the tire circumference. The third tire width direction portion is located in the inner half of the tire width direction when the tire is mounted on the vehicle, and When viewed from the radial outer side of the tire, the tire carcass cords and the belt cords in the tire body portion of the third tire width direction extend in directions that intersect each other.

6. The pneumatic radial tire for passenger cars according to any one of claims 1 to 4, wherein, The tire body is arranged in a ring between the pairs of bead portions.

7. The pneumatic radial tire for passenger cars according to claim 5, wherein, The tire body is arranged in a ring between the pairs of bead portions.

8. The pneumatic radial tire for passenger cars according to any one of claims 1 to 4, wherein, The tire body has a first tire body and a second tire body, the first tire body extending from the bead portion of the outer half of the tire width direction when the tire is mounted on the vehicle to the radially inner side of the tire belt portion, and the second tire body extending from the bead portion of the inner half of the tire width direction when the tire is mounted on the vehicle to the radially inner side of the tire belt portion.

9. The pneumatic radial tire for passenger vehicles according to claim 5, wherein, The tire body has a first tire body and a second tire body, the first tire body extending from the bead portion of the outer half of the tire width direction when the tire is mounted on the vehicle to the radially inner side of the tire belt portion, and the second tire body extending from the bead portion of the inner half of the tire width direction when the tire is mounted on the vehicle to the radially inner side of the tire belt portion.

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