pneumatic tires

Abstract

To provide a pneumatic tire provided with a communication device and improved in the durability of the antenna of the communication device.SOLUTION: A pneumatic tire according to the present invention includes a carcass toroidally extending over a pair of bead portions and including one or more carcass plies, and the carcass ply is formed by rubber-coating carcass cords arranged in a radial direction. A communication device including an antenna is provided in the pneumatic tire, and the antenna includes a portion in which a predetermined shape is repeated at a pitch interval A (mm) in an extending direction while reciprocating in a direction orthogonal to the extending direction. The carcass cords are arranged at a pitch interval P (mm) in a tire circumferential direction at a tire radial position where the communication device is provided; and the pitch interval A (mm) is greater than the pitch interval P (mm).SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a pneumatic tire. [Background technology]

[0002] Conventionally, pneumatic tires equipped with a communication device such as an RF (Radio Frequency) tag having a memory or the like for reading and writing data for tire manufacturing management, shipping management, usage history management, etc. have been known (for example, Patent Document 1). As such a communication device, one has been proposed in which the antenna has a portion in which a predetermined shape is repeatedly arranged (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-037235 [Patent Document 2] Japanese Patent Publication No. 2022-084145 Summary of the Invention [Problem to be solved by the invention]

[0004] When the inventors considered installing a communication device equipped with an antenna having a portion in which a predetermined shape is repeatedly arranged in a pneumatic tire, they found that there were cases in which the durability of the antenna was insufficient.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a pneumatic tire equipped with a communication device and having an antenna of the communication device with improved durability. [Means for solving the problem]

[0006] The gist and configuration of the present invention are as follows. (1) A pneumatic tire having a carcass consisting of one or more carcass plies that spans a pair of bead portions in a toroidal manner, The carcass ply is formed by rubber-coating radially arranged carcass cords, a communication device having an antenna is provided in the pneumatic tire, The antenna has a portion in which predetermined shapes are repeatedly arranged at a pitch interval A (mm) in the extension direction while reciprocating in a direction perpendicular to the extension direction, The carcass cords are arranged at a pitch interval P (mm) in the tire circumferential direction at a tire radial position where the communication device is provided, A pneumatic tire, wherein the pitch interval A (mm) is larger than the pitch interval P (mm). Here, the "pitch interval P" of the carcass cord means the distance between the centers of adjacent carcass cords.

[0007] (2) The antenna has a first portion extending in a direction perpendicular to the extension direction and a second portion extending in the extension direction; The pneumatic tire according to (1) above, wherein the second portion intersects with two or three of the carcass cords when viewed from a direction perpendicular to the surface of the pneumatic tire.

[0008] (3) The pneumatic tire according to (1) or (2), wherein the portion in which predetermined shapes are repeatedly arranged at a pitch interval A (mm) in the extension direction is a serpentine shape, a wave shape, or a zigzag shape. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a pneumatic tire equipped with a communication device and having an antenna of the communication device with improved durability. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a plan view of an RF tag. [Figure 2] FIG. 1 is a perspective view of an RF tag. [Figure 3] FIG. 2 is a perspective view of the RF tag with the lid of the exterior body removed. [Figure 4]FIG. 2 is an exploded perspective view of an RF tag. [Figure 5] FIG. 2 is a plan view of a second antenna. [Figure 6] FIG. 1 is a partial cross-sectional view of an RF tag. [Figure 7] 1 is a cross-sectional view (half) in the tire width direction of a pneumatic tire according to one embodiment of the present invention. [Figure 8] 10 is a diagram for explaining pitch intervals P and A. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0012] <Communication Device> First, the communication device provided in the pneumatic tire will be described.

[0013] [Communication Device] FIG. 1 is a plan view of a communication device 10. A communication device is sometimes called an "RF tag." FIG. 2 is a perspective view of the RF tag 10. FIG. 3 is a perspective view of the RF tag 10 with the cover of the exterior body removed. FIG. 4 is an exploded perspective view of the RF tag 10. FIG. 5 is a plan view of the second antenna 2. FIG. 6 is a partial cross-sectional view of the RF tag 10. FIG. 6 is a cross-sectional view taken along line II of FIG. 2.

[0014] As shown in FIGS. 1 and 2, the RF tag 10 includes a substrate 1, a second antenna 2, and an exterior body 3. The longitudinal direction (left-right direction in FIG. 1) of the main surface 31a of the exterior body 3 (see FIG. 3) is referred to as the X direction. One of the X directions (rightward in FIG. 1) is referred to as the +X direction. The other of the X directions (leftward in FIG. 1) is referred to as the -X direction. The lateral direction of the main surface 31a of the exterior body 3 (see FIG. 3) is referred to as the Y direction. The Y direction is perpendicular to the X direction in a plane along the main surface 31a. One of the Y directions (upward in FIG. 1) is referred to as the +Y direction. The other of the Y directions (downward in FIG. 1) is referred to as the -Y direction. The direction perpendicular to the main surface 31a of the exterior body 3 is referred to as the Z direction. The Z direction is perpendicular to the X direction and the Y direction. A view from the Z direction is referred to as a planar view. The Z axis is a central axis along the Z direction.

[0015] 3, the substrate 1 includes an RFID chip 11, a first antenna 12, and a base material 13. The substrate 1 is provided with the RFID chip 11 and the first antenna 12.

[0016] The substrate 13 is formed in a plate shape. The shape of the substrate 13 in a plan view is not particularly limited, but it is preferable that at least a part of the outer peripheral edge 13a is curved. Examples of the curved shape include an elliptical arc shape, a circular arc shape, and a high-order curve shape (e.g., a quadratic curve shape). Examples of the high-order curve shape include a parabolic shape and a hyperbolic shape. The outer shape of the substrate 13 in a plan view may be, for example, an elliptical shape, a circular shape, an oval shape (a racetrack shape), or the like. It is desirable that the outer shape of the substrate 13 in a plan view is non-circular. In this embodiment, the substrate 13 is elliptical. The substrate 13 is oriented such that the major axis direction faces the X direction. The substrate 13 may be made of a glass epoxy resin substrate, ceramics, a plastic film, or the like.

[0017] Information can be written to and read from the RFID chip 11 in a non-contact manner via the first antenna 12 and the second antenna 2. The RFID chip 11 is mounted on a substrate 13.

[0018] The first antenna 12 is, for example, a conductive layer formed on one surface of the substrate 13. The conductive layer is, for example, composed of a conductive foil, a plating layer, a conductive ink layer, or the like. The conductive foil is, for example, a metal foil composed of copper, silver, gold, platinum, aluminum, or the like. The conductive foil is formed into a predetermined shape by etching or the like. The plating layer is, for example, composed of a metal such as copper, silver, gold, platinum, aluminum, or the like. The conductive ink layer is formed by printing or the like using a conductive ink. The conductive ink contains conductive particles formed of a metal, carbon material, or the like.

[0019] The first antenna 12 is formed in a loop shape. The first antenna 12 has, for example, a curved shape that follows the outer peripheral edge 13a of the base material 13. The first antenna 12 is formed in an elliptical loop shape. The first antenna 12 is electrically connected to the RFID chip 11.

[0020] The second antenna 2 is an antenna for a booster. The second antenna 2 is, for example, a linear body. The second antenna 2 is formed of a metal such as steel, stainless steel, copper, or a copper alloy. The second antenna 2 can be formed of, for example, a brass-plated steel wire. The second antenna 2 is separate from the substrate 1. Although the second antenna 2 is a linear body, the second antenna may also be, for example, a plate-shaped body.

[0021] The second antenna 2 includes an electromagnetic field coupling portion 21 and a pair of extension portions 22. The electromagnetic field coupling portion 21 has a curved shape. A "curved shape" is a shape that curves smoothly without any sharp bends. Examples of curved shapes include an elliptical arc shape, a circular arc shape, and a high-order curve shape (e.g., a quadratic curve shape). Examples of "high-order curve shapes" include a parabolic shape and a hyperbolic shape. The electromagnetic field coupling portion 21 has a semi-elliptical shape. More specifically, the electromagnetic field coupling portion 21 has a semi-elliptical shape that extends from one vertex of the ellipse (the vertex intersecting with the major axis) to the other vertex (the vertex intersecting with the major axis).

[0022] In a plan view, electromagnetic field coupling unit 21 has a shape that surrounds at least a portion of substrate 1. Electromagnetic field coupling unit 21 surrounds the range (half the circumference on the +Y direction side) from one vertex (the vertex intersecting with the major axis) of elliptical substrate 1 to the other vertex (the vertex intersecting with the major axis).

[0023] In a plan view, electromagnetic field coupling portion 21 has a curved shape (for example, an elliptical arc shape) that follows outer peripheral edge 12a of first antenna 12. The distance between electromagnetic field coupling portion 21 and outer peripheral edge 12a is approximately constant. In a plan view, electromagnetic field coupling portion 21 is located outside outer peripheral edge 13a of substrate 1 and close to outer peripheral edge 13a. In a plan view, electromagnetic field coupling portion 21 has a shape that follows outer peripheral edge 13a. The distance between electromagnetic field coupling portion 21 and outer peripheral edge 13a is approximately constant.

[0024] The electromagnetic field coupling unit 21 is electromagnetically coupled to the first antenna 12 in a non-contact manner. The electromagnetic field coupling is, for example, one of electric field coupling and magnetic field coupling. The shape of a cross section of the electromagnetic field coupling unit 21 perpendicular to the longitudinal direction is, for example, circular (see FIG. 6).

[0025] The pair of extending portions 22 extend from one and the other end portions 21a of the electromagnetic field coupling portion 21. As shown in Fig. 5 , the first extending portion 22A, which is one of the pair of extending portions 22, extends in the -X direction while meandering from the -X direction end portion 21a of the electromagnetic field coupling portion 21. The second extending portion 22B, which is the other of the pair of extending portions 22, extends in the +X direction while meandering from the +X direction end portion 21a of the electromagnetic field coupling portion 21.

[0026] The shape of the extending portion 22 in a plan view is, for example, a meandering shape, a wavy shape, a zigzag shape, etc. The extending portion 22 has a meandering shape.

[0027] As shown in Fig. 4, the extension portion 22 includes a plurality of straight portions 23 and a plurality of folded portions 24. The straight portions 23 are linearly shaped along the Y direction. The plurality of straight portions 23 are arranged at intervals in the X direction. The folded portions 24 connect the ends of adjacent straight portions 23. The folded portions 24 have a curved shape (for example, an arc shape).

[0028] Of the multiple straight line portions 23, the straight line portion 23 closest to the electromagnetic field coupling portion 21 is referred to as the "first straight line portion 23A." Of the multiple straight line portions 23, the straight line portion 23 second closest to the electromagnetic field coupling portion 21 is referred to as the "second straight line portion 23B." Of the multiple straight line portions 23, the straight line portion 23 third closest to the electromagnetic field coupling portion 21 is referred to as the "third straight line portion 23C." The folded portion 24 connecting the first straight line portion 23A and the second straight line portion 23B is referred to as the "first folded portion 24A." The folded portion 24 connecting the second straight line portion 23B and the third straight line portion 23C is referred to as the "second folded portion 24B."

[0029] First straight portion 23A extends in the -Y direction from end 21a of electromagnetic field coupling portion 21. First folded portion 24A extends in a curved manner from the -Y direction end of first straight portion 23A and reaches the -Y direction end of second straight portion 23B. Of extension portion 22, first straight portion 23A and a portion of first folded portion 24A are located inside exterior body 3, but the remaining portion of extension portion 22 extends outside exterior body 3 (see FIG. 3 ).

[0030] As shown in Fig. 2, the exterior body 3 includes a plate-shaped main body 31 and a plate-shaped lid 32. The exterior body 3 is generally plate-shaped. The main body 31 and the lid 32 are formed of, for example, a resin. Examples of resins include polyamide resins such as nylon 6,6; polyester resins such as polyethylene terephthalate (PET); polyolefin resins such as polyethylene; polyethylene fluoride-based resins such as polyvinyl fluoride; vinyl polymers such as polyvinyl chloride; and acrylic resins such as polymethyl methacrylate.

[0031] 4, the main body 31 has a rectangular shape in a plan view. A substrate holding recess 37 (substrate holding portion), an antenna holding groove 34, and a pair of side recesses 35 are formed on a main surface 31a, which is one surface of the main body 31. The substrate holding recess 37 is formed by the substrate holding protrusions 33. The substrate holding recess 37 is a recess surrounded by the substrate holding protrusions 33.

[0032] The substrate holding protrusion 33 is an annular rib-shaped protrusion. The substrate holding protrusion 33 has a curved shape (e.g., an elliptical shape) that follows the outer peripheral edge 13a of the substrate 1. The substrate holding protrusion 33 protrudes in the +Z direction from the main surface 31a. The shape of a cross section perpendicular to the longitudinal direction of the substrate holding protrusion 33 is, for example, rectangular. In a plan view, the substrate holding protrusion 33 has a curved shape (e.g., an elliptical shape) that follows the outer peripheral edge 12a of the first antenna 12.

[0033] The substrate holding recess 37 holds the substrate 1. The substrate holding recess 37 has a shape (for example, an elliptical shape) that follows the outer peripheral edge 13a of the substrate 1. The inner dimension (inner diameter) of the substrate holding recess 37 is approximately the same as the outer dimension (outer diameter) of the substrate 1, or is slightly larger than the outer dimension (outer diameter) of the substrate 1. The substrate holding recess 37 has a similar shape to the substrate 1 in a plan view.

[0034] If the substrate 1 and the substrate holding recess 37 are non-circular (for example, elliptical), tilting of the substrate 1 around the Z axis can be prevented, and the correct posture of the substrate 1 can be maintained. As a result, the electromagnetic coupling between the first antenna 12 and the electromagnetic field coupling portion 21 can be maintained.

[0035] The antenna holding groove 34 accommodates the electromagnetic field coupling portion 21 of the second antenna 2 (see FIGS. 3 and 6). The antenna holding groove 34 is formed outside the board holding protrusion 33 and close to the board holding protrusion 33. The antenna holding groove 34 has a shape that follows the board holding protrusion 33 in a plan view. The antenna holding groove 34 has a curved shape (e.g., an elliptical arc shape) that follows the outer peripheral edge 12a of the first antenna 12 in a plan view. The antenna holding groove 34 has a curved shape (e.g., an elliptical arc shape) that follows the outer peripheral edge 13a of the board 1 in a plan view. The antenna holding groove 34 has a semi-elliptical shape in a plan view. More specifically, the antenna holding groove 34 has a semi-elliptical shape that extends from one vertex of the ellipse (the vertex intersecting with the major axis) to the other vertex (the vertex intersecting with the major axis).

[0036] In a plan view, the antenna holding groove 34 is shaped to surround at least a portion of the substrate 1. The antenna holding groove 34 surrounds the range from one vertex (the vertex intersecting with the major axis) of the elliptical substrate 1 to the other vertex (the vertex intersecting with the major axis) (a range covering half the circumference on the +Y direction side).

[0037] As shown in FIG. 6, the cross section perpendicular to the longitudinal direction of the antenna holding groove 34 is, for example, rectangular. The width (inner dimension) W1 of the antenna holding groove 34 is larger than the outer diameter (outer dimension) D1 of the electromagnetic field coupling portion 21. The difference between the width W1 and the outer diameter D1 can be, for example, 0.01 mm to 1 mm (preferably 0.05 mm to 0.2 mm). Because the width W1 of the antenna holding groove 34 is larger than the outer diameter D1 of the electromagnetic field coupling portion 21, the electromagnetic field coupling portion 21 is accommodated in the antenna holding groove 34 in a state in which it can be displaced in the radial direction (for example, the Y direction). The "radial direction" is the direction perpendicular to the longitudinal direction of the electromagnetic field coupling portion 21. The electromagnetic field coupling portion 21 can also be displaced in the longitudinal direction relative to the antenna holding groove 34.

[0038] The depth of antenna holding groove 34 is determined so that height (inner dimension) H1 from bottom surface 34a of antenna holding groove 34 to lid portion 32 (top surface 38a) is greater than outer diameter D1 of electromagnetic field coupling portion 21. The difference between height H1 and outer diameter D1 can be, for example, 0.01 mm to 1 mm (preferably 0.05 mm to 0.2 mm). Because height H1 of antenna holding groove 34 is greater than outer diameter D1 of electromagnetic field coupling portion 21, electromagnetic field coupling portion 21 is accommodated in antenna holding groove 34 in a state where it can be displaced in the wire diameter direction (for example, Z direction).

[0039] 4, the side recesses 35 are formed on one and the other side portions of the main surface 31a. The side recesses 35 are formed in an area including the side edge 31b in the X direction of the main body 31. The inner peripheral edge 35a of the side recess 35 has a first linear portion 35b extending along the Y direction, a curved portion 35c, and a second linear portion 35d extending along the X direction.

[0040] The first linear portion 35b is a portion that extends in the -Y direction from an end of the inner peripheral edge of the antenna holding groove 34. The curved portion 35c is a portion that extends from the tip of the first linear portion 35b while decreasing its inclination angle with respect to the X direction. The second linear portion 35d is a portion that extends from the tip of the curved portion 35c along the X direction toward the side edge 31b.

[0041] 3, the side recess 35 encompasses the first straight portion 23A and a portion of the first folded portion 24A of the second antenna 2 in a plan view. The first straight portion 23A is adjacent to the first straight portion 35b (see FIG. 4). The first folded portion 24A is adjacent to the curved portion 35c (see FIG. 4). The side recess 35 accommodates at least a portion of a predetermined length range of the second antenna 2 (the first straight portion 23A and a portion of the first folded portion 24A).

[0042] As shown in Fig. 2, since the side recess 35 has a sufficient distance in the Y direction, a slit-shaped side end opening 36 extending in the Y direction (a direction along the main surface 31a) is formed in the side end edge 31b. The second antenna 2 extends to the outside of the exterior body 3 through the side end opening 36. As shown in Fig. 4, two locking recesses 39 are formed at different positions in the X direction in the +Y direction edge 31c of the main body 31. Two locking recesses 39 are also formed at different positions in the X direction in the -Y direction edge 31d of the main body 31.

[0043] 2, the lid portion 32 has a rectangular shape in a plan view. The lid portion 32 has the same shape as the main body portion 31 and is disposed opposite the main surface 31a of the main body portion 31. The lid portion 32 is disposed so as to overlap the main surface 31a of the main body portion 31 in a plan view.

[0044] 6, the opposing surface 32a of the cover 32 is the surface that faces the main surface 31a of the main body 31. A positioning groove 38 is formed in the opposing surface 32a. The positioning groove 38 is an annular groove. The cross section of the positioning groove 38 that is perpendicular to the longitudinal direction has, for example, a rectangular shape.

[0045] The positioning groove 38 has a curved shape (for example, an elliptical shape) that corresponds to the board holding protrusion 33 and the antenna holding groove 34. In a plan view, the positioning groove 38 has a width that collectively encompasses the board holding protrusion 33 and the antenna holding groove 34. A portion of the top surface 38a of the positioning groove 38 faces the bottom surface 34a of the antenna holding groove 34.

[0046] 2, two locking protrusions 40 are formed at different positions in the X direction on the +Y edge 32c of the lid 32. Two locking protrusions 40 are also formed at different positions in the X direction on the -Y edge 32d of the lid 32.

[0047] The locking protrusion 40 has a locking claw portion (not shown) formed at its tip. The locking protrusion 40 is inserted into the locking recess 39 of the main body 31. The locking claw portion of the locking protrusion 40 locks into the main body 31. This allows the lid 32 to be detachably connected to the main body 31.

[0048] The exterior body 3 is not fixed to the second antenna 2. In other words, the exterior body 3 is not fixed to the second antenna 2.

[0049] The RF tag 10 can be attached to a molded product made of, for example, rubber, resin, or the like. For example, the RF tag 10 can be embedded in the molded product. The molded product is, for example, an elastic body and is elastically deformable. When the molded product is stretched, bent, or otherwise deformed, an external force may act on the second antenna 2. For example, a tensile force may act on the extension portion 22 in a direction away from the exterior body 3 along the X direction. A force may also act on the extension portion 22 in a direction toward the exterior body 3 along the X direction. As in this embodiment, when the RF tag 10 is attached to a tire, the RF tag 10 can be embedded in a fixing member (lamination rubber) made of a rubber sheet. This not only reliably prevents damage to the RF tag 10, but also allows the RFID tag 10 to be easily embedded in the tire 1 without risk of damage by embedding the RF tag 10 in the fixing member before embedding it in the tire.

[0050] [Effects of RF tags] In the RF tag 10, the electromagnetic field coupling portion 21 of the second antenna 2 is accommodated in the antenna holding groove 34 in a state in which it is displaceable in the radial direction (a direction perpendicular to the longitudinal direction of the electromagnetic field coupling portion 21) (see FIG. 6). Because the electromagnetic field coupling portion 21 is displaceable, when an external force acts on the second antenna 2, stress in the second antenna 2 can be alleviated. This makes it less likely that the second antenna 2 will be damaged. On the other hand, when the second antenna is fixed to the exterior body, when an external force acts on the second antenna, stress concentrates on the base end (root portion) of the second antenna extending from the exterior body, and this location may be more susceptible to damage.

[0051] The electromagnetic field coupling portion 21 of the second antenna 2 has a shape that follows the outer peripheral edge 12a of the first antenna 12, so that the electromagnetic field coupling portion 21 can be sufficiently electromagnetically coupled to the first antenna 12. The antenna holding groove 34 is formed along the outer peripheral edge 12a of the first antenna 12, so that the electromagnetic field coupling portion 21 of the second antenna 2 can be disposed along the first antenna 12. Therefore, the electromagnetic field coupling portion 21 can be sufficiently electromagnetically coupled to the first antenna 12.

[0052] Because the electromagnetic field coupling portion 21 of the second antenna 2 has a curved shape (for example, a semi-elliptical shape), stress concentration is less likely to occur compared to a rectangular shape, even when an external force acts on the second antenna 2. This makes it possible to make the second antenna 2 less likely to be damaged. In contrast, if the electromagnetic field coupling portion is rectangular, stress will concentrate at the corners (bends) when an external force acts on the second antenna, and damage may be more likely to occur at these locations.

[0053] Since the antenna holding groove 34 is formed along the outer peripheral edge 13a of the substrate 1, the electromagnetic field coupling portion 21 of the second antenna 2 can be disposed along the first antenna 12. Therefore, the electromagnetic field coupling portion 21 can be sufficiently electromagnetically coupled to the first antenna 12.

[0054] The exterior body 3 includes a main body 31 and a lid 32 that is overlaid on the main surface 31a. The board holding recess 37 and the antenna holding groove 34 are formed on the main surface 31a. Therefore, the lid 32 can prevent the board 1 and the second antenna 2 from falling off the main body 31. Therefore, the board 1 and the second antenna 2 can be stably held in the exterior body 3.

[0055] In the RF tag 10, a slit-shaped side end opening 36 extending in the Y direction (the direction along the main surface 31a) is formed in the side end edge 31b of the exterior body 3. This allows the second antenna 2 to move in the Y direction relative to the exterior body 3. Therefore, when an external force acts on the second antenna 2, the stress is easily alleviated by the displacement. This makes it possible to make the second antenna 2 less likely to be damaged.

[0056] For example, in the RF tag 10, the outer periphery 13a of the substrate 1 and the outer periphery 12a of the first antenna 12 are curved along the entire circumference, but the outer peripheries of the substrate and the first antenna may be partially curved. The exterior body 3 includes a main body 31 and a lid 32, but the configuration of the exterior body is not particularly limited. For example, the exterior body does not need to include a lid. The exterior body is not limited to a plate shape and may have other shapes (such as a block shape).

[0057] As described above, the communication device 10 has an antenna. The antenna has a portion (extension portion 22) in which a predetermined shape is repeatedly arranged in the extension direction at a pitch interval A (mm) (see FIG. 8) while reciprocating in a direction perpendicular to the extension direction. Specific examples of the shape of the portion (extension portion 22) include a serpentine shape, a wave shape, or a zigzag shape. Note that FIG. 8 shows only one of a pair of antennas, and the antenna extending in the opposite direction is not shown.

[0058] <Pneumatic tires> Fig. 7 is a tire widthwise cross-sectional view of a pneumatic tire according to one embodiment of the present invention. Fig. 7 shows only one half in the tire width direction bounded by the tire equatorial plane CL, but the other half has a similar configuration. On the other hand, the pneumatic tire may have an asymmetric portion bounded by the tire equatorial plane CL. Fig. 8 is a diagram for explaining the pitch interval P and the pitch interval A.

[0059] This pneumatic tire 50 is a tire for trucks and buses, but may also be a tire for other heavy loads or a tire for passenger cars.

[0060] The internal structure of the tire is not particularly limited, but the following configuration can be exemplified. The tire 50 includes a pair of bead portions 51, a pair of sidewall portions 52 connected to the bead portions 51, and a tread portion 53 connected to the pair of sidewall portions 52. A bead core 51a is embedded in the bead portion 51, and a bead filler 51b is disposed on the tire radial outer side of the bead core 51a. The tire 50 also includes a carcass 54 consisting of one or more carcass plies that toroidally spans between the pair of bead portions 50. The carcass ply includes radially arranged carcass cords 54a coated with rubber, and the carcass cords are arranged in the tire radial direction at a pitch interval P (mm) at a position where the communication device 10 is provided. In this example, the carcass cords are made of steel cords. The number of carcass plies is not particularly limited. The pitch interval P (mm) is not particularly limited, but may be, for example, 2.0 to 4.0 mm. The diameter of the carcass cord is not particularly limited, but can be set to 0.5 to 1.5 mm.

[0061] A belt 55 consisting of one or more belt layers 55a to 55d (four layers in the illustrated example) is disposed on the radially outer side of the crown portion of the carcass 54, and tread rubber is disposed on the radially outer side of the belt 55. In this example, the belt cords of the belt 55 are steel cords. The belt cords can be inclined at an angle of, for example, 30 to 60 degrees with respect to the circumferential direction of the tire. There are no particular limitations on the number of belt layers or the belt width.

[0062] The tire 50 is equipped with an RF tag as a communication device. The RF tag includes an IC chip and an antenna. The RF tag may be sandwiched between multiple components of the same or different types that make up the tire. This facilitates attachment of the RF tag during tire production, improving the productivity of tires equipped with RF tags. In this example, the RF tag is embedded in the sidewall portion 52. However, it may also be sandwiched between a bead filler and another component adjacent to the bead filler. The RF tag may be embedded in any of the components that make up the tire. This reduces the load on the RF tag compared to when the RF tag is sandwiched between multiple components that make up the tire. This improves the durability of the RF tag. In this example, the RF tag may be embedded in a rubber component such as a tread rubber or side rubber. It is preferable that the RF tag is not placed at a boundary between components with different rigidities in the periphery length direction, which is the direction along the outer surface of the tire in a cross-sectional view in the tire width direction. By doing so, the RF tag is not placed in a position where distortion is likely to concentrate due to a difference in rigidity. Therefore, the load applied to the RF tag can be reduced. This can improve the durability of the RF tag. In this example, it is preferable that the RF tag is not placed in a position that is, for example, a boundary between the end of the carcass and a member adjacent to the end of the carcass (for example, a side rubber) in a cross-sectional view in the tire width direction. The number of RF tags is not particularly limited. A tire may be equipped with only one RF tag, or may be equipped with two or more RF tags. Here, an RF tag is described as an example of a communication device, but a communication device other than an RF tag may also be used.

[0063] The RF tag may be disposed, for example, in the tread portion of the tire. In this way, the RF tag will not be damaged by a side cut of the tire. The RF tag may be disposed, for example, on the inner surface of the tire tread portion of the tire. The RF tag may be disposed, for example, in the tread center portion in the tire width direction. The tread center portion is a position in the tread portion where flexure is less likely to concentrate. In this way, the load applied to the RF tag can be reduced. This improves the durability of the RF tag. Also, it is possible to prevent differences in communication with the RF tag from both outer sides of the tire in the tire width direction. In this example, the RF tag may be disposed, for example, within a range of half the tread width centered on the tire equatorial plane in the tire width direction. The RF tag may be disposed, for example, at a tread edge in the tire width direction. If the position of a reader that communicates with the RF tag is predetermined, the RF tag may be disposed, for example, at one tread edge closer to the reader. In this example, the RF tag may be arranged, for example, within a range of ¼ of the tread width in the tire width direction, with the tread end being the outer end.

[0064] The RF tag may be positioned, for example, closer to the tire cavity than a carcass including one or more carcass plies spanning between bead portions. This configuration makes the RF tag less susceptible to damage from external impacts to the tire, side cuts, nail penetration, and other damage. As one example, the RF tag may be positioned in close contact with the surface of the carcass facing the tire cavity. As another example, if there is another component closer to the tire cavity than the carcass, the RF tag may be positioned between the carcass and another component located closer to the tire cavity than the carcass. An example of another component located closer to the tire cavity than the carcass is an inner liner that forms the tire inner surface. As another example, the RF tag may be attached to the inner surface of the tire facing the tire cavity. Configuring the RF tag to be attached to the inner surface of the tire makes it easier to attach the RF tag to the tire and to inspect and replace the RF tag. In other words, the ease of attaching and maintaining the RF tag can be improved. Furthermore, by attaching the RF tag to the inner surface of the tire, it is possible to prevent the RF tag from becoming the core of tire failure, compared to a configuration in which the RF tag is embedded in the tire. Furthermore, when the carcass has multiple carcass plies and there is a position where multiple carcass plies are overlapped, the RF tag may be disposed between the overlapped carcass plies.

[0065] The RF tag may be arranged, for example, in the tread portion of the tire, radially outward of a belt including one or more belt plies. As one example, the RF tag may be arranged radially outward of the belt in the tire radial direction and in close contact with the belt. As another example, if a reinforcing belt layer is provided, the RF tag may be arranged radially outward of the reinforcing belt layer in close contact with the reinforcing belt layer. As another example, the RF tag may be embedded in the tread rubber radially outward of the belt. By arranging the RF tag radially outward of the belt in the tread portion of the tire, communication with the RF tag from outside the tire in the tire radial direction is less likely to be obstructed by the belt. Therefore, communication with the RF tag from outside the tire in the tire radial direction can be improved. As another example, the RF tag may be arranged radially inward of the belt in the tread portion of the tire. In this way, the radially outward side of the RF tag is covered by the belt, making the RF tag less susceptible to damage from impacts from the tread surface or nail penetration. As one example, the RF tag may be placed in the tread portion of the tire, between the belt and the carcass located radially inward of the belt. Also, if the belt has multiple belt plies, the RF tag may be placed in the tread portion of the tire, between any two belt plies. In this way, the outer side of the RF tag in the tire radial direction is covered by one or more belt plies, making the RF tag less susceptible to damage from impacts from the tread surface or nail penetration.

[0066] The RF tag may be disposed, for example, sandwiched between the cushion rubber and the tread rubber or between the cushion rubber and the side rubber. In this way, the cushion rubber can absorb impacts on the RF tag. This improves the durability of the RF tag. The RF tag may also be embedded in the cushion rubber. Furthermore, the cushion rubber may be made up of multiple adjacent rubber members of the same or different types. In such a case, the RF tag may be disposed sandwiched between the multiple rubber members that make up the cushion rubber.

[0067] The RF tag may be disposed, for example, in a sidewall portion or a bead portion of the tire. The RF tag may be disposed, for example, in one sidewall portion or one bead portion that is closer to a reader capable of communicating with the RF tag. This arrangement improves communication between the RF tag and the reader. As an example, the RF tag may be disposed between the carcass and the side rubber or between the tread rubber and the side rubber. The RF tag may be disposed, for example, between the tire's maximum width position and the tread surface position in the tire radial direction. This arrangement improves communication with the RF tag from outside the tire in the tire radial direction, compared to a configuration in which the RF tag is disposed radially inward of the tire's maximum width position. The RF tag may be disposed, for example, radially inward of the tire's maximum width position. This arrangement allows the RF tag to be disposed near the bead portion, which has high rigidity. This reduces the load applied to the RF tag, thereby improving the durability of the RF tag. As an example, the RF tag may be disposed adjacent to the bead core in the tire radial direction or the tire width direction. Distortion is less likely to concentrate near the bead core. This reduces the load on the RF tag, improving its durability. In particular, it is preferable to position the RF tag radially inward of the tire's maximum width and radially outward of the bead core of the bead portion. This improves the durability of the RF tag, and communication between the RF tag and a reader is less likely to be obstructed by the bead core, improving the RF tag's communication performance. Furthermore, when the side rubber is composed of multiple rubber members of the same or different types adjacent to each other in the tire radial direction, the RF tag may be sandwiched between the multiple rubber members that make up the side rubber. The RF tag may be positioned, for example, on the outer surface of the side rubber.

[0068] The RF tag may be disposed sandwiched between a stiffener (bead filler) and a member adjacent to the stiffener. In this way, the RF tag can be disposed in a position where the stiffener prevents strain concentration. This reduces the load on the RF tag, thereby improving the durability of the RF tag. The RF tag may be disposed sandwiched between, for example, the stiffener and a side rubber. The RF tag may also be disposed sandwiched between, for example, the stiffener and a carcass. The portion of the carcass that sandwiches the RF tag together with the stiffener may be located on the outer side of the stiffener in the tire width direction, or on the inner side of the tire width direction. When the portion of the carcass that sandwiches the RF tag together with the stiffener is located on the outer side of the stiffener in the tire width direction, the load on the RF tag due to impact or damage from the outside of the tire in the tire width direction can be further reduced. This further improves the durability of the RF tag. The stiffener may have a portion disposed adjacent to a rubber chafer. In such a case, the RF tag may be disposed sandwiched between the stiffener and the rubber chafer. The stiffener may have a portion adjacent to the hat rubber on the outer side in the tire width direction. In such a case, the RF tag may be disposed sandwiched between the stiffener and the hat rubber. The stiffener may be composed of a plurality of rubber members with different hardnesses. In such a case, the RF tag may be disposed sandwiched between a plurality of rubber members constituting the stiffener. The RF tag may be disposed sandwiched between the hat rubber and a member adjacent to the hat rubber. The RF tag may be disposed sandwiched, for example, between the hat rubber and the carcass ply. In this way, impacts on the RF tag can be absorbed by the hat rubber. This can improve the durability of the RF tag.

[0069] The RF tag may be disposed, for example, sandwiched between the rubber chafer and the side rubber. In this way, the RF tag can be disposed in a position where the placement of the rubber chafer makes it less likely for distortion to concentrate. This reduces the load on the RF tag. This improves the durability of the RF tag. The RF tag may be disposed, for example, sandwiched between the rubber chafer and the carcass. In this way, it reduces the load on the RF tag due to impact or damage from the rim. This improves the durability of the RF tag.

[0070] The RF tag may be sandwiched between the nylon chafer and another member adjacent to the nylon chafer on the outer or inner side in the tire width direction. This makes it difficult for the position of the RF tag to fluctuate when the tire deforms. This reduces the load applied to the RF tag when the tire deforms. This improves the durability of the RF tag. The nylon chafer may, for example, have a portion adjacent to the rubber chafer on the outer side in the tire width direction. In this case, the RF tag may be sandwiched between the nylon chafer and the rubber chafer. The nylon chafer may, for example, have a portion adjacent to the side rubber on the outer side in the tire width direction. In this case, the RF tag may be sandwiched between the nylon chafer and the side rubber. The nylon chafer may, for example, have a portion adjacent to the stiffener on the inner side in the tire width direction. In this case, the RF tag may be sandwiched between the nylon chafer and the stiffener. Furthermore, the nylon chafer may have a portion adjacent to the hat rubber, for example, on the inner side in the tire width direction. In such a case, the RF tag may be disposed by being sandwiched between the nylon chafer and the hat rubber. Furthermore, the nylon chafer may have a portion adjacent to the carcass, for example, on the inner side in the tire width direction. In such a case, the RF tag may be disposed by being sandwiched between the nylon chafer and the carcass. Furthermore, the nylon chafer may have a portion adjacent to the wire chafer, for example, on the inner side in the tire width direction. In such a case, the RF tag may be disposed by being sandwiched between the nylon chafer and the wire chafer. In this way, the RF tag may be sandwiched between the nylon chafer and another adjacent member on the outer or inner side of the nylon chafer in the tire width direction. In particular, by covering the outer side of the RF tag in the tire width direction with the nylon chafer, the load applied to the RF tag due to impact or damage from the outside of the tire in the tire width direction can be further reduced. This can further improve the durability of the RF tag.

[0071] The RF tag may be sandwiched between the wire chafer and another adjacent member on the inner or outer side of the wire chafer in the tire width direction. This makes it difficult for the position of the RF tag to fluctuate when the tire deforms. This reduces the load applied to the RF tag when the tire deforms. This improves the durability of the RF tag. The other adjacent member on the inner or outer side of the wire chafer in the tire width direction may be, for example, a rubber member such as a rubber chafer. Furthermore, the other adjacent member on the inner or outer side of the wire chafer in the tire width direction may be, for example, a carcass.

[0072] Here, as shown in Figure 8, the carcass cords (if there are multiple carcass plies, the carcass cord of the carcass ply closest to the RF tag) are arranged at a pitch interval P (mm) in the circumferential direction of the tire at the tire radial position where the communication device 10 (RF tag) is provided, and the antenna has a portion in which a predetermined shape is repeatedly arranged in the extension direction (in the illustrated example, in the circumferential direction of the tire) at a pitch interval A (mm) while moving back and forth in a direction perpendicular to the extension direction, and the pitch interval A (mm) is greater than the pitch interval P (mm). The effects of the pneumatic tire of this embodiment will be described below.

[0073] In the pneumatic tire of this embodiment, the pitch interval A (mm) is greater than the pitch interval P (mm), which improves the durability of the antenna of the communication device. That is, if the pitch interval A (mm) is smaller than (or equal to) the pitch interval P (mm), adjacent straight portions 23 may interfere with (contact) each other when the tire rolls, thereby reducing the durability of the antenna (and ultimately the durability of the communication device). In addition, the ratio A / P is preferably 6 or less, which prevents the antenna communication performance from being reduced due to the distance between the straight portions being too large compared to the pitch interval of the carcass cord, thereby ensuring communication performance due to the antenna effect.

[0074] The antenna has a first portion (straight portion 23 in the illustrated example) extending in a direction perpendicular to the extension direction and a second portion (folded portion 24 in the illustrated example) extending in the extension direction. When viewed from a direction perpendicular to the surface of the pneumatic tire (for example, when the RF tag is located further outboard in the tire width direction than the carcass, when viewed from the outside of the tire in a direction perpendicular to the outer surface, or when the RF tag is located on the inner surface of the tire, when viewed from the inside of the tire in a direction perpendicular to the inner surface), the second portion preferably intersects two or three carcass cords. This allows the durability and communication capabilities of the communication device antenna to be improved. In particular, it is preferable that the second portion closest to the exterior body 3 intersects two or three carcass cords. This is because failures are more likely to occur in the second portion closest to the exterior body 3, and therefore it is effective to increase durability in this portion.

[0075] Furthermore, the portion in which predetermined shapes are repeatedly arranged at a pitch interval A (mm) in the extension direction is preferably serpentine, wavy, or zigzag, because such shapes have a long path length per unit extension length (length in the X direction in FIG. 1), which is advantageous for improving communication performance.

[0076] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, Fig. 8 shows a case where the extending direction of the antenna extension portion 22 is the tire circumferential direction (i.e., the direction of the pitch interval of the carcass cord and the direction of the pitch interval of the straight portion 23 of the antenna extension portion 22 are the same), but the extending direction of the antenna extension portion 22 may be inclined with respect to the tire circumferential direction.

[0077] [Contribution to the United Nations-led Sustainable Development Goals (SDGs)] The SDGs have been proposed to realize a sustainable society. One embodiment of the present invention is thought to be a technology that can contribute to "No. 12 Responsible Consumption and Production." [Explanation of symbols]

[0078] 1: substrate; 2: second antenna; 3: exterior body; 10: RF tag (communication device), 11: RFID chip, 12: first antenna, 12a: outer periphery, 21: Electromagnetic field coupling part, 21a: End part, 22: Extension part, 34: Antenna holding groove, 37: Substrate holding recess (substrate holding portion), 50: pneumatic tire, 51: bead portion, 52: Sidewall portion, 53: Tread portion, 54: Carcass, 55: Belt, CL: Tire equatorial plane

Claims

1. A pneumatic tire having a carcass made up of one or more carcass plies toroidally spanning a pair of bead portions, The carcass ply is formed by rubber-coating radially arranged carcass cords, a communication device having an antenna is provided in the pneumatic tire, The antenna has a portion in which predetermined shapes are repeatedly arranged at a pitch interval A (mm) in the extension direction while reciprocating in a direction perpendicular to the extension direction, the carcass cords are arranged at a pitch interval P (mm) in the tire circumferential direction at a tire radial position where the communication device is provided, The pitch interval A (mm) is greater than the pitch interval P (mm), the communication device includes an exterior body; the antenna has an extension portion extending from the exterior body, the antenna has a first portion extending in a direction perpendicular to the extension direction and a second portion extending in the extension direction; When viewed from a direction perpendicular to the surface of the pneumatic tire, the second portion of the extension portion closest to the exterior body intersects with two or three carcass cords.

2. The pneumatic tire according to claim 1 , wherein the portion in which predetermined shapes are repeatedly arranged at a pitch interval A (mm) in the extending direction is a serpentine shape, a wave shape, or a zigzag shape.

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