Tire for heavy load

Abstract

To provide a tire 2 for a heavy load, which can suppress occurrence of damage due to existence of an RFID tag 60.SOLUTION: A tire 2 comprises a pair of chafers 8 and a tag member 26. The chafers 8 contact a rim R. The tag member 26 includes an RFID tag 60. The rim R is a normal rim. In a normal state, the tire 2 is assembled to the rim R, and inner pressure of the tire 2 is adjusted to normal inner pressure. In a standard grounding state, loads corresponding to 50% of normal loads are applied to the tire 2 in the normal state and the tire 2 is contacted with a flat surface FS. In the standard grounding state, the RFID tag 60 is positioned between an outer end PRa in an axial direction of the rim R and a maximum width position PWs of the tire 2, in the axial direction, and is positioned between an outer end PRr in a radial direction of the rim R and the maximum width position PWs of the tire 2, in the radial direction.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] It has been proposed to embed an RFID (Radio Frequency Identification) tag in a tire in order to manage data such as tire manufacturing management, customer information, driving history, etc. Various studies have been conducted on the technology of embedding an RFID tag in a tire (for example, Patent Document 1 listed below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-046057 Summary of the Invention [Problem to be solved by the invention]

[0004] Tires repeatedly undergo deformation and recovery. When a tire is in motion, the edges of the tread and areas near the widest point are the most active. To prevent damage to the RFID tag itself, the RFID tag is placed in areas with less movement. In the case of heavy-duty tires, the bead portion has great rigidity, so placing the RFID tag in this bead portion is being considered.

[0005] RFID tags are foreign objects to tires, so even if the position of the RFID tag is determined from the viewpoint of preventing damage to the RFID tag itself and creating a good communication environment, there is a risk that the presence of the RFID tag will increase distortion and cause damage.

[0006] Even if a tire is for heavy loads, it is not always used under conditions where a load close to the normal load acts on the tire. Sometimes tires are used under conditions where a load of about 50% of the normal load (light load) acts on the tire. If the location where the RFID tag is located is sensitive to the action of the load, the distortion will increase even under a light load.

[0007] Heavy-duty tires are used over a wide range of loads, from light to heavy. To ensure that the presence of an RFID tag does not reduce the durability of the tire, it is important to check whether the placement of the RFID tag increases distortion even under light loads.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a heavy-duty tire that can suppress the occurrence of damage caused by the presence of an RFID tag. [Means for solving the problem]

[0009] The heavy-duty tire according to the present invention includes a pair of beads, a carcass that spans between the pair of beads, a belt that is located radially outside the carcass and includes a large number of parallel belt cords, a pair of sidewalls that are located axially outside the carcass, a pair of chafers that are located radially inside the sidewalls and contact the rim, and a tag member that includes an RFID tag. The bead includes a core and an apex that is located radially outside the core. The carcass includes a carcass ply. The carcass ply includes a ply body that spans between the pair of beads, and a pair of folded-up parts that are connected to the ply body and folded back at the bead. The belt includes three or less belt plies that are arranged radially. The rim is a regular rim, and the tire is assembled on the rim and the internal pressure of the tire is adjusted to the regular internal pressure, which is the regular state. The standard ground contact state is when a load of 50% of the regular load is applied to the tire in the regular state and the tire is brought into contact with a flat surface. In the standard ground contact condition, the RFID tag is located axially between the axially outer end of the rim and the maximum width position of the tire, and radially between the radially outer end of the rim and the maximum width position of the tire. Effect of the Invention

[0010] According to the present invention, a heavy-duty tire can be obtained that can suppress the occurrence of damage caused by the presence of an RFID tag. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing a portion of a heavy duty tire according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing a portion of the tire of FIG. [Diagram 3] FIG. 11 is a cross-sectional view showing a modified example of the cord reinforcement layer. [Figure 4] FIG. [Diagram 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 1 is a cross-sectional view of a portion of a tire in a ground contact state. [Figure 7] FIG. 1 is a cross-sectional view of a portion of a tire in a ground contact state. [Figure 8] FIG. 3 is a cross-sectional view showing the contour of the carcass. [Figure 9] FIG. 2 is a cross-sectional view illustrating the specification of the contour of the carcass. [Figure 10] FIG. 11 is a cross-sectional view illustrating another carcass profile. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

[0013] The tire of the present invention is mounted on a rim. Air is filled inside the tire, and the internal pressure of the tire is adjusted. The tire mounted on the rim is also called a tire-rim assembly. The tire-rim assembly includes a rim and a tire mounted on the rim.

[0014] In the present invention, a state in which a tire is mounted on a standard rim, the internal pressure of the tire is adjusted to a standard internal pressure, and no load is applied to the tire is referred to as a standard state.

[0015] In the present invention, unless otherwise specified, the dimensions and angles of each part of the tire are measured in a normal state. The dimensions and angles of each part in a meridian section of a tire, which cannot be measured with the tire mounted on a regular rim, are measured on the section obtained by cutting the tire along a plane including the rotation axis. In this measurement, the tire is set so that the distance between the left and right beads corresponds to the distance between the beads of the tire mounted on a regular rim.

[0016] A genuine rim is a rim that is specified in the standard on which the tire is based. The "standard rim" in the JATMA standard, the "Design Rim" in the TRA standard, and the "Measuring Rim" in the ETRTO standard are genuine rims.

[0017] Normal tire pressure means the internal pressure specified in the standard on which the tire is based. The "maximum air pressure" in the JATMA standard, the "maximum value" listed in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the TRA standard, and the "INFLATION PRESSURE" in the ETRTO standard are normal tire pressures.

[0018] Normal load refers to the load specified in the standard on which the tire is based. The "maximum load capacity" in the JATMA standard, the "maximum value" listed in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the TRA standard, and the "LOAD CAPACITY" in the ETRTO standard are normal loads.

[0019] In the present invention, the tread portion of a tire is the portion of the tire that comes into contact with the road surface. The bead portion is the portion of the tire that fits onto the rim. The sidewall portion is the portion of the tire that bridges between the tread portion and the bead portion. A tire has the following portions: a tread portion, a pair of bead portions, and a pair of sidewall portions.

[0020] In the present invention, the complex modulus of an element made of crosslinked rubber among elements constituting a tire is measured in accordance with the provisions of JIS K 6394. The measurement conditions are as follows. Initial distortion = 10% Dynamic distortion = ±1% Frequency = 10Hz Mode = Decompression mode Temperature=70℃ In this measurement, a test piece (length 40 mm x width 4 mm x thickness 1 mm) is sampled from the tire. The length direction of the test piece is aligned with the circumferential direction of the tire. If it is not possible to sample a test piece from the tire, the test piece is sampled from a sheet-like crosslinked rubber (hereinafter also referred to as a rubber sheet) obtained by pressing and heating the rubber composition used to form the element to be measured at a temperature of 170°C for 12 minutes. In the present invention, the complex modulus is represented by the loss tangent at 70°C.

[0021] [Overview of the embodiment of the present invention] [Configuration 1] A heavy-duty tire according to one aspect of the present invention includes a pair of beads, a carcass spanning the pair of beads, a belt located radially outward of the carcass and including a number of parallel belt cords, a pair of sidewalls located axially outward of the carcass, a pair of chafers located radially inward of the sidewalls and in contact with a rim, and a tag member including an RFID tag, the bead includes a core and an apex located radially outward of the core, the carcass includes a carcass ply, the carcass ply includes a ply body spanning the pair of beads, and a ply member connected to the ply body. the tire has a pair of folded-up portions that are folded back at the bead, the belt has three or less belt plies arranged radially, the rim is a regular rim, the regular state is when the tire is mounted on the rim and the internal pressure of the tire is adjusted to the regular internal pressure, and the standard ground contact state is when a load of 50% of the regular load is applied to the tire in the regular state and the tire is brought into contact with a flat surface, and in the standard ground contact state, the RFID tag is located axially between the axial outer end of the rim and the maximum width position of the tire, and radially between the radial outer end of the rim and the maximum width position of the tire.

[0022] By arranging the tire in this manner, the RFID tag is positioned away from the edge of the rim flange and away from the tire's maximum width, where the presence of an RFID tag would cause significant distortion. This tire is less susceptible to the RFID tag contributing to increased distortion. This tire is therefore less susceptible to damage caused by the presence of the RFID tag, and is also less susceptible to damage to the RFID tag itself. The tire maintains good durability despite having an RFID tag built into it.

[0023] [Configuration 2] Preferably, in the tire described in the above-mentioned [Configuration 1], in the standard ground contact state, the RFID tag is located axially between the end of the folded-back portion and the maximum width position of the carcass, and radially between the end of the folded-back portion and the maximum width position of the carcass. By arranging the tire in this manner, the RFID tag is positioned far enough away from the flange ends and the maximum width location, where the presence of an RFID tag could cause significant distortion. In this tire, the presence of the RFID tag is effectively prevented from contributing to increased distortion. In this tire, damage caused by the presence of the RFID tag is effectively prevented. Moreover, damage to the RFID tag itself is effectively prevented. In this tire, good durability is maintained despite the incorporation of an RFID tag.

[0024] [Configuration 3] Preferably, in the tire according to the above-mentioned [Configuration 1] or [Configuration 2], the shortest distance from the outer surface of the tire to the RFID tag is 3.5 mm or more. By trimming the tire in this way, the RFID tag is covered with a rubber having a sufficient thickness, which effectively prevents the presence of the RFID tag from contributing to an increase in distortion of the tire, and effectively prevents damage caused by the presence of the RFID tag.

[0025] [Configuration 4] Preferably, in the tire according to any one of the above-mentioned [Configuration 1] to [Configuration 3], in a meridian section of the tire in the normal state, the contour of the carcass includes, at a radially inner portion of a maximum width position of the carcass, a curved portion that bulges outward, and a reverse curved portion that is located radially inside the curved portion and recesses inward, the reverse curved portion is connected to the curved portion, a boundary between the curved portion and the reverse curved portion is an inflection point, a part or all of the curved portion is represented by a first arc that includes the inflection point, a part or all of the reverse curved portion is represented by a second arc that includes the inflection point, the first arc and the second arc are tangent at the inflection point, and the RFID tag is located radially outside the inflection point. By trimming the tire in this manner, it is possible to effectively prevent the presence of the RFID tag from contributing to an increase in distortion. In this tire, the occurrence of damage caused by the presence of the RFID tag is effectively prevented. Moreover, it is also possible to effectively prevent damage to the RFID tag itself. In this tire 2, good durability is maintained despite the incorporation of the RFID tag.

[0026] [Configuration 5] Preferably, in a tire described in any one of the above-mentioned [Configuration 1] to [Configuration 4], the apex comprises an inner apex located radially outside the core and an outer apex located radially outside the inner apex, the outer apex being softer than the inner apex, the tag member contacts the outer apex radially outside the end of the folded-back portion, and the RFID tag is located radially between the outer end of the outer apex and the end of the folded-back portion. By arranging the tire in this manner, the soft outer apex is located axially inside the RFID tag, so that the presence of the RFID tag is effectively prevented from contributing to an increase in distortion. In this tire, the occurrence of damage caused by the presence of the RFID tag is prevented. Moreover, damage to the RFID tag itself is also prevented. In this tire, good durability is maintained despite the incorporation of the RFID tag. Furthermore, since the outer apex is located between the carcass ply and the RFID tag, the RFID tag is disposed at a distance from the carcass ply. Even if the carcass ply contains a steel cord as a carcass cord, radio wave disturbance is unlikely to occur, so that a good communication environment is formed between the RFID tag and a communication device (not shown). Data is written to the RFID tag and data recorded in the RFID tag is read accurately.

[0027] [Configuration 6] Preferably, in the tire described in the above-mentioned [Configuration 5], the tag member is located between the outer end of the outer apex and the sidewall, between the outer end of the outer apex and the outer end of the chafer. By trimming the tires in this manner, it is possible to improve the readability of the RFID tag and reduce the risk of damage to the tires while minimizing the impact on their durability.

[0028] [Configuration 7] Preferably, in the tire according to any one of the above-mentioned [Configuration 1] to [Configuration 6], an outer end of the chafer is located radially outward of an inner end of the sidewall, and the sidewall covers the outer end of the chafer. By trimming the tire in this way, the strain acting on the outer edge of the chafer is effectively relieved. The tire is less susceptible to damage caused by the presence of an RFID tag. Moreover, damage to the RFID tag itself is also suppressed. The tire maintains good durability despite the incorporation of an RFID tag.

[0029] [Configuration 8] Preferably, in a tire according to any one of the above-mentioned [Configuration 1] to [Configuration 7], the tag member is a plate-shaped member in which the RFID tag is covered with crosslinked rubber, and the thickness of the tag member is 1.0 mm or more and 2.5 mm or less. By arranging the tires in this way, the risk of damage to the RFID tags is reduced and a good communication environment is created.

[0030] [Configuration 9] Preferably, in the tire according to any one of the above-mentioned [Configuration 1] to [Configuration 8], the number of the belt plies included in the belt is two or less. By aligning the tire in this way, the belt contributes to reducing the tire's weight.

[0031] [Configuration 10] Preferably, the tire described in any one of the above-mentioned [Configuration 1] to [Configuration 9] includes a band located radially outside the carcass and including a spirally wound band cord, the band including a full band having opposite ends across an equatorial plane, and the belt ply and the full band are aligned radially. By aligning the tire in this manner, the band restrains the movement of the tread portion, thereby suppressing deformation of the entire tire.

[0032] [Details of the embodiment of the present invention] 1 shows a part of a heavy duty tire 2 (hereinafter also simply referred to as "tire 2") according to one embodiment of the present invention. This tire 2 is mounted on vehicles such as trucks and buses. In FIG. 1, a tire 2 is mounted on a rim R (a regular rim).

[0033] Fig. 1 shows a part of a cross section (hereinafter, meridian cross section) of this tire 2 along a plane including the rotation axis of the tire 2. In Fig. 1, the left-right direction is the axial direction of the tire 2, and the up-down direction is the radial direction of the tire 2. The direction perpendicular to the plane of Fig. 1 is the circumferential direction of the tire 2. Figure 2 shows a part of the cross section shown in Figure 1. Figure 2 shows a bead portion of a tire 2.

[0034] 1, a dashed line CL extending in the radial direction represents the equatorial plane of the tire 2. A solid line BBL extending in the axial direction in Figures 1 and 2 represents a bead base line. The bead base line is a line that defines the rim diameter of the rim R (see JATMA, etc.).

[0035] The tire 2 includes a tread 4, a pair of sidewalls 6, a pair of chafers 8, a pair of beads 10, a carcass 12, a cord reinforcing layer 14, a pair of cushion layers 16, a strip layer 18, a pair of steel reinforcing layers 20, an interlayer strip 22, an inner liner 24, and a tag member 26.

[0036] The tread 4 is located radially outward of the carcass 12. The tread 4 comes into contact with the road surface at a tread surface 28. The tread 4 has grooves 30 formed therein. The tread 4 includes a base portion 32 and a cap portion 34 located radially outward of the base portion 32. The base portion 32 is made of a crosslinked rubber with low heat generation. The cap portion 34 is made of a crosslinked rubber with consideration given to wear resistance and grip performance. The cap portion 34 includes the tread surface 28.

[0037] 1, the position indicated by the symbol PC is the equator. The equator PC is the intersection of the tread surface 28 and the equatorial plane. When the grooves 30 are located on the equatorial plane as in this tire 2, the equator PC is determined based on a virtual tread surface obtained by assuming that the grooves 30 do not exist. The radial distance from the bead base line to the equator PC, obtained in a tire 2 in a normal state, is the section height of this tire 2 (see JATMA, etc.).

[0038] Each sidewall 6 is continuous with an edge of the tread 4. The sidewall 6 is located radially inward of the tread 4. The sidewall 6 is located axially outward of the carcass 12. The position indicated by the symbol PS is the inner end of the sidewall 6. The sidewall 6 is made of a crosslinked rubber having good cut resistance. The complex elastic modulus of the sidewall is 2.0 MPa or more and 6.0 MPa or less.

[0039] The position indicated by the symbol PW is the axially outer end (hereinafter, outer end PW) of the tire 2. If there is a decoration such as a pattern or lettering on the outer surface, the outer end PW is determined based on a virtual outer surface obtained by assuming that there is no decoration. The tire 2 shows its maximum width at the outer end PW. The outer end PW is also called the maximum width position. In the present invention, the maximum width position PW of the tire 2 in a normal state is the reference maximum width position PWb. The axial distance from the first reference maximum width position PWb to the second reference maximum width position PWb (not shown) is the section width of the tire 2 (see JATMA, etc.).

[0040] 1, the length indicated by the symbol H is the radial distance from the bead base line to the reference maximum width position PWb. The radial distance H is also called the radial height of the reference maximum width position PWb. In the tire 2 in a normal state, the ratio of the radial height H of the reference maximum width position PWb to the cross-sectional height is equal to or greater than 0.40 and is equal to or less than 0.60.

[0041] Each chafer 8 is located radially inside the sidewall 6. The chafer 8 contacts the rim R. The position indicated by the symbol PB is the outer end of the chafer 8. The chafer 8 is made of a crosslinked rubber in consideration of wear resistance. The complex elastic modulus of the chafer 8 is 10 MPa or more and 15 MPa or less. The chafer 8 is harder than the sidewall 6.

[0042] Each bead 10 is located axially inward of the chafer 8. The beads 10 are located radially inward of the sidewall 6. Each bead 10 includes a core 36 and an apex 38.

[0043] The core 36 extends in the circumferential direction and includes a core body 36m and a wrapping layer 36r. The core body 36m is a ring extending in the circumferential direction. The core body 36m includes a steel wire wound in the circumferential direction. The cross-sectional shape of the core body 36m is arranged by regularly winding the wire. As a result, in the cross section of the core body 36m, cross-sectional units each consisting of a cross section of a plurality of wires arranged in parallel in the approximately axial direction are stacked in a plurality of stages in the approximately radial direction. The cross-sectional shape of the core body 36m is represented by a line circumscribing the core body 36m. As shown in FIG. 1, the core body 36m has a hexagonal cross-sectional shape. This core body 36m may have a quadrilateral cross-sectional shape.

[0044] The core body 36m has approximately six side surfaces 36ms. As shown in FIG. 1, one side surface 36msb of the six side surfaces 36ms is disposed so as to face the seat Rs of the rim R. In the present disclosure, the side surface 36msb disposed so as to face the seat Rs of the rim R is the bottom surface of the core body 36m. The core body 36m has a bottom surface 32msb disposed so as to face the seat Rs of the rim R. In the meridian cross section of the tire 2, the contour of the bottom surface 32msb is represented by a straight line.

[0045] The wrapping layer 36r surrounds the periphery of the core body 36m. The wrapping layer 36r covers the core body 36m. The wrapping layer 36r prevents the core body 36m from coming apart. The wrapping layer 36r is not particularly limited in configuration as long as it can prevent the core body 36m from coming apart. The wrapping layer 36r is composed of a cord wound in a spiral shape around the core body 36m, a rubber-coated cloth wrapped around the core body 36m, or the like.

[0046] The apex 38 is located radially outward of the core 36. The apex 38 extends radially outward from the core 36. The apex 38 tapers outward. An outer end PA of the apex 38 is located radially outward of an outer end PB of the chafer 8.

[0047] The apex 38 includes an inner apex 40 and an outer apex 42. The inner apex 40 is located radially outward of the core 36. The outer apex 42 is located radially outward of the inner apex 40.

[0048] The inner apex 40 is outwardly tapered. The inner apex 40 is made of a hard crosslinked rubber. The complex modulus of elasticity of the inner apex 40 is 60 MPa or more and 90 MPa or less.

[0049] The outer apex 42 is thick near the outer end PU of the inner apex 40. The outer apex 42 tapers inwardly from this thickened portion and then tapers outwardly. An inner end PG1 of the outer apex 42 is located near the core 36. An outer end PG2 of the outer apex 42 is also an outer end PA of the apex 38.

[0050] 2 is the radial distance from the bead base line to the outer end PG2 of the outer apex 42. The radial distance L1 is also called the radial height of the outer end PG2 of the outer apex 42. The outer end PG2 of the outer apex 42 is also the outer end PA of the apex 38. This radial distance L1 is also called the radial height of the bead 10.

[0051] In this tire 2, the outer end PA of the apex 38 is disposed radially inward of the reference maximum width position PWb from the viewpoint of achieving a good balance between the rigidity of the bead portion and the deflection of the tire 2. Specifically, the ratio (L1 / H) of the radial height L1 of the bead 10 to the radial height H of the maximum width position PWb is adjusted within a range of 0.55 to 0.95.

[0052] The outer apex 42 is made of a crosslinked rubber. The outer apex 42 is softer than the inner apex 40. The complex elastic modulus of the outer apex 42 is not less than 3.0 MPa and not more than 6.0 MPa.

[0053] The apex 38 of the tire 2 further includes an edge strip 44 . The edge strip 44 is located axially outward of the outer apex 42 and constitutes a part of the outer surface of the apex 38. The edge strip 44 is located radially between the outer end PB of the chafer 8 and the inner end PG1 of the outer apex 42. The edge strip 44 is made of a crosslinked rubber. The edge strip 44 is softer than the chafer 8 and harder than the outer apex 42. The complex elastic modulus of the edge strip 44 is 7.0 MPa or more and 12 MPa or less.

[0054] The carcass 12 is located inside the tread 4, the pair of sidewalls 6, and the pair of chafers 8. The carcass 12 spans between the pair of beads 10. The carcass 12 of the tire 2 has a radial structure.

[0055] The carcass 12 includes at least one carcass ply 46. The carcass 12 of the tire 2 includes one carcass ply 46. The carcass ply 46 is turned up at each of the beads 10.

[0056] The carcass ply 46 includes a ply body 48 and a pair of turnup portions 50. The ply body 48 spans between a pair of beads 10, i.e., between a first bead 10 and a second bead 10 (not shown). Each turnup portion 50 is connected to the ply body 48 and turned up at the bead 10. The turnup portions 50 of the tire 2 are turned up at the bead 10 from the axially inner side toward the axially outer side. An end PF of the turnup portion 50 is located radially inner of an outer end PB of the chafer 8. The bead 10 is sandwiched between the ply body 48 and the turnup portion 50.

[0057] Although not shown, the carcass ply 46 includes a number of carcass cords arranged in parallel. These carcass cords are covered with a topping rubber. Each carcass cord crosses the equatorial plane. The angle that the carcass cord makes with the equatorial plane (hereinafter, the crossing angle of the carcass cord) is 70° or more and 90° or less. The material of the carcass cord is steel. The carcass cord is a steel cord.

[0058] 1, the length indicated by the symbol N is the radial distance from the bead base line to the end PF of the turned-up portion 50. The radial distance N is also called the radial height of the end PF of the turned-up portion 50. In the tire 2, the ratio (N / H) of the radial height N of the end PF of the turned-up portion 50 to the radial height H of the reference maximum width position PWb is equal to or greater than 0.25 and is equal to or less than 0.45.

[0059] The cord reinforcement layer 14 is located radially outward of the carcass 12. The cord reinforcement layer 14 is located radially inward of the tread 4. The cord reinforcement layer 14 of the tire 2 includes a belt 52. The belt 52 includes three or less belt plies 54. The belt 52 is lighter than a belt including four belt plies 54. The belt 52 can contribute to reducing the weight of the tire 2. The belt 52 shown in FIG. 1 includes three belt plies 54. The three belt plies 54 are a first belt ply 54A, a second belt ply 54B, and a third belt ply 54C. These belt plies 54 are arranged in a radial direction. As shown in FIG. 1, the first belt ply 54A located at the innermost side in the radial direction has the widest width, and the third belt ply 54C located at the outermost side in the radial direction has the narrowest width. An end of the first belt ply 54A is an end of the belt 52.

[0060] In the tire 2, the number of belt plies 54 included in the belt 52 may be two or less. Providing the belt 52 with two or less belt plies 54 arranged in the radial direction can effectively contribute to reducing the weight of the tire 2. When the belt 52 is composed of two belt plies 54, the belt 52 is composed of a wide first belt ply 54A and a second belt ply 54B that is next wide after the first belt ply 54A.

[0061] Although not shown, each belt ply 54 constituting the belt 52 includes a number of belt cords arranged in parallel. Each belt cord is inclined with respect to the equator plane. In the tire 2, the inclination direction of the belt cord included in the second belt ply 54B, i.e., the second belt cord, is opposite to the inclination direction of the belt cord included in the first belt ply 54A, i.e., the first belt cord. The inclination direction of the belt cord included in the third belt ply 54C, i.e., the third belt cord, is the same as the inclination direction of the second belt cord. The inclination direction of the third belt cord may be opposite to the inclination direction of the second belt cord. The angle that the first belt cord makes with respect to the equatorial plane, i.e., the inclination angle of the first belt cord, is preferably 15° or more and 30° or less. The inclination angle of the first belt cord is more preferably 20° or less. The angle that the second belt cord makes with respect to the equatorial plane, i.e., the inclination angle of the second belt cord, is preferably 15° or more and 30° or less. The inclination angle of the second belt cord is more preferably 20° or less. The angle that the third belt cord makes with respect to the equatorial plane, i.e., the inclination angle of the third belt cord, is more preferably 15° or more and 50° or less. The inclination angle of the third belt cord is further preferably 25° or less. The belt cord is made of steel. The belt cord is a steel cord.

[0062] 3 shows a modified example of the cord reinforcement layer 14. This cord reinforcement layer 14 includes a band 56 in addition to the above-mentioned belt 52. Since the band 56 restricts the movement of the tread portion, deformation of the entire tire 2 is suppressed.

[0063] Although not shown, the band 56 includes a band cord wound in a spiral shape. The band cord is a steel cord. This band cord may be a cord made of organic fiber (hereinafter, organic fiber cord). When the band cord is an organic fiber cord, examples of the organic fiber include nylon fiber, polyester fiber, rayon fiber, and aramid fiber.

[0064] The band 56 of the tire 2 includes a full band 58. As shown in Fig. 3, the full band 58 is disposed such that both ends face each other across the equatorial plane. Although not shown, the band 56 may include a pair of edge bands disposed spaced apart in the axial direction.

[0065] As described above, the belt 52 of the tire 2 includes three belt plies 54. The three belt plies 54 and the full band 58 are arranged in the radial direction. In the cord reinforcement layer 14 shown in FIG. 3, the full band 58 is located between the first belt ply 54A and the second belt ply 54B. The full band 58 may be disposed between the second belt ply 54B and the third belt ply 54C. The full band 58 may be disposed on the radial inner side of the first belt ply 54A. The full band 58 may be disposed on the radial outer side of the third belt ply 54C.

[0066] An end of the full band 58 is located axially inward of an end of the belt 54. In the cord-reinforced layer 14 shown in Fig. 3, an end of the full band 58 is located axially inward of an end of the first belt ply 54A, and an end of the second belt ply 54B. An end of the full band 58 is located axially outward of an end of the third belt ply 54C. The ends of the belt 54 are the ends of the cord-reinforced layer 14.

[0067] 3, from the viewpoint of weight reduction, the number of belt plies 54 included in the belt 52 may be two or less. When the belt 52 is composed of two belt plies 54, the belt 52 is composed of a wide first belt ply 54A and a second belt ply 54B that is next in width to the first belt ply 54A.

[0068] Each cushion layer 16 is located at an end of the cord reinforcing layer 14 between the cord reinforcing layer 14 and the carcass 12. The cushion layer 16 is made of a soft crosslinked rubber.

[0069] The strip layer 18 is located between the carcass 12 and the cord reinforcing layer 14 on the radially inner side of the tread 4. The strip layer 18 is laminated to the carcass 12, and the cord reinforcing layer 14 is laminated to the strip layer 18. The strip layer 18 is located between the first cushion layer 16 and the second cushion layer 16 in the axial direction. The strip layer 18 is made of crosslinked rubber. In the tire 2, the strip layer 18 may not be provided. In this case, the cord reinforcing layer 14 is laminated to the carcass 12.

[0070] Each steel reinforcing layer 20 is located in a bead portion. The steel reinforcing layer 20 is located between the bead 10 and the chafer 8. The steel reinforcing layer 20 is located between the carcass 12 and the chafer 8. The steel reinforcing layer 20 is turned up at the bead 10. The steel reinforcing layer 20 is disposed so as to wrap the radially inner portion of the bead 10 from the radially inner side of the turned-up portion 50. The inner end 20s and the outer end 20f of the steel reinforcing layer 20 are located between the end PF of the turned-up portion 50 and the core 36 in the radial direction. Although not shown, the steel reinforcing layer 20 includes a number of filler cords arranged in parallel. The filler cords are made of steel. The steel reinforcing layer 20 includes steel cords. In the steel reinforcing layer 20, the steel cords are covered with a topping rubber.

[0071] The outer end 20f of the steel reinforcing layer 20 is located between the turned-up portion 50 and the chafer 8 in the axial direction. The outer end 20f is located radially inside the end PF of the turned-up portion 50. The inner end 20s is located axially between the inner liner 24 and the ply body 48. The radial position of the inner end 20s may be approximately the same as that of the outer end 20f, and the inner end 20s may be located radially outside the outer end 20f or may be located radially inside the outer end 20f.

[0072] Each interlayer strip 22 is axially located between a chafer 8 and an apex 38. The interlayer strips 22 cover the end PF of the turnup portion 50 and the outer end 20f of the steel reinforcing layer 20. The interlayer strip 22 contacts the apex 38 radially outside the end PF of the turned-up portion 50. In other words, the contact surface between the interlayer strip 22 and the apex 38 forms a part of the outer surface of the apex 38 (or the inner surface of the interlayer strip 22). The interlayer strip 22 contacts the chafer 8 radially outside the outer end 20f of the steel reinforcing layer 20. In other words, the contact surface between the interlayer strip 22 and the chafer 8 constitutes a part of the inner surface of the chafer 8 (or the outer surface of the interlayer strip 22). The interlayer strip 22 is made of a crosslinked rubber. The interlayer strip 22 is harder than the sidewall 6 and softer than the chafer 8. The complex elastic modulus of the interlayer strip 22 is 7.0 MPa or more and 12 MPa or less.

[0073] The inner liner 24 is positioned inside the carcass 12. The inner liner 24 is joined to the inner surface of the carcass 12 via an insulation (not shown) made of crosslinked rubber. The inner liner 24 constitutes the inner surface of the tire 2. The inner liner 24 is made of crosslinked rubber with excellent air barrier properties.

[0074] The tag member 26 is located axially outside the bead 10. In the tire 2, the tag member 26 is provided only on one sidewall 6 of a pair of sidewalls 6 provided on the tire 2. The tag member 26 may be provided on both the one sidewall 6 and the other sidewall 6. From the viewpoint of reducing the risk of damage, it is preferable that the tag member 26 is provided on one sidewall 6 of the pair of sidewalls 6.

[0075] Fig. 4 is a plan view of the tag member 26. Fig. 5 is a cross-sectional view taken along line VV in Fig. 4. The tag member 26 has a plate shape. The tag member 26 is long in the length direction and short in the width direction. As shown in Fig. 2, the tag member 26 is disposed in the tire 2 such that a first end 26s in the width direction is located on the radial outer side of the tire 2 and a second end 26u is located on the inner side. In this tire 2, the first end 26s is also called the outer end, and the second end 26u is also called the inner end.

[0076] The tag member 26 includes an RFID tag 60. In FIG. 4, the RFID tag 60 is shown by a solid line for ease of explanation, and is entirely covered with a protective body 62. The tag member 26 includes the RFID tag 60 and a protective body 62. The RFID tag 60 is located at the center of the tag member 26. The protective body 62 is made of crosslinked rubber. The protective body 62 has a rigidity similar to that of the outer apex 42. In this tire 2, the formation of a good communication environment is taken into consideration, and a crosslinked rubber having high electrical resistance is used for the protective body 62. The protective body 62 is made of rubber with high insulating properties.

[0077] Although not described in detail, the RFID tag 60 is a small and lightweight electronic component consisting of a semiconductor chip 64 that integrates a transmitting / receiving circuit, a control circuit, a memory, etc., and an antenna 66. When the RFID tag 60 receives an interrogation radio wave, it uses the received signal as electrical energy and transmits the various data stored in the memory as a response radio wave. This RFID tag 60 is a type of passive radio frequency identification transponder.

[0078] The tag member 26 is a plate-shaped member in which the RFID tag 60 is covered with crosslinked rubber. From the viewpoints of reducing the risk of damage to the RFID tag 60 and forming a good communication environment, the thickness of the tag member 26 in the tire 2 is preferably 1.0 mm or more and 2.5 mm or less. The thickness of the tag member 26 in the tire 2 is represented by the maximum thickness of the tag member 26 in the semiconductor chip 64 of the RFID tag 60. The length TL of the tag member 26 before being embedded in the tire 2 is 60 mm or more and 80 mm or less, and the width TW is 10 mm or more and 20 mm or less.

[0079] 2, the position indicated by the symbol TU is the radially inner end of the RFID tag 60 (specifically, the semiconductor chip 64). The position indicated by the symbol TS is the radially outer end of the semiconductor chip 64, i.e., the radially outer end of the RFID tag 60. In the present invention, when the inner end TU of the RFID tag 60 in the tire 2 is located radially outward from a reference position (hereinafter, the reference position), the RFID tag 60 is located radially outward from the reference position. When the outer end TS of the RFID tag 60 in the tire 2 is located radially inward from the reference position, the RFID tag 60 is located radially inward from the reference position.

[0080] Fig. 6 shows a part of a meridian cross section of a tire 2 in a ground contact state. The cross section in Fig. 6 is a trace of a cross-sectional image of the tire 2 taken, for example, by a computed tomography method using X-rays (hereinafter, referred to as the X-ray CT method) in a state where a load of 50% of the normal load is applied to the tire 2 in a normal state and the tire 2 is brought into contact with a flat surface FS. In the present invention, a state in which a load of 50% of the normal load is applied to the tire 2 in a normal state and the tire 2 is brought into contact with a plane FS is also called a standard contact state. In the standard contact state shown in FIG. 6, the tire camber angle is set to 0 degrees.

[0081] 6, the position indicated by the symbol PRa is the axially outer end of the flange Rf of the rim R. The dashed dotted line indicated by the symbol LRa is a straight line that passes through the axially outer end PRa and extends in the radial direction. The position indicated by the symbol PRr is the radially outer end of the flange Rf. The dashed line indicated by the symbol LRr is a straight line that passes through the radially outer end PRr and extends in the axial direction. 6, the position indicated by the symbol PWs is the maximum width position of the tire 2 in a standard contact state. The dashed line indicated by the symbol LWsa is a straight line that passes through the maximum width position PWs and extends in the radial direction. The dashed line indicated by the symbol LWsr is a straight line that passes through the maximum width position PWs and extends in the axial direction.

[0082] 6, in the standard ground contact state, the RFID tag 60 is located axially between the axial outer end PRa of the rim R and the maximum width position PWs of the tire 2, and radially between the radial outer end PRr and the maximum width position PWs of the rim R. In other words, the RFID tag 60 is located in the area surrounded by the dashed dotted lines LWsr and LWsa and the dashed dotted lines LRr and LRa.

[0083] In this tire 2, the RFID tag 60 is placed away from the vicinity of the end of the flange Rf and the vicinity of the maximum width position PWs, where there is a risk of large distortion occurring if the RFID tag 60 is present. In this tire 2, the presence of the RFID tag 60 is prevented from contributing to an increase in distortion. This tire 2 is prevented from causing damage due to the presence of the RFID tag 60. Moreover, damage to the RFID tag 60 itself is also prevented. In this tire 2, even though the RFID tag 60 is built in, good durability is maintained.

[0084] 7 shows a part of a meridian section of the tire 2 in contact with the ground. FIG. 7 shows the same section as shown in FIG.

[0085] 7, the dashed dotted line indicated by the symbol LFa is a straight line extending in the radial direction and passing through the end PF of the turn-back portion 50. The dashed dotted line indicated by the symbol LFr is a straight line extending in the axial direction and passing through the end PF of the turn-back portion 50. 7, the position indicated by the symbol PPs is the maximum width position of the carcass 12 in the standard ground contact state. The dashed line indicated by the symbol LPsa is a straight line that passes through the maximum width position PPs and extends in the radial direction. The dashed line indicated by the symbol LPsr is a straight line that passes through the maximum width position PPs and extends in the axial direction.

[0086] 7, in the standard grounding state, the RFID tag 60 is located in the axial direction between the end PF of the folded-back portion 50 and the maximum width position PPs of the carcass 12, and in the radial direction between the end PF of the folded-back portion 50 and the maximum width position PPs of the carcass 12. In other words, the RFID tag 60 is located in the area surrounded by the dashed dotted lines LPsr and LPsa and the dashed dotted lines LFr and LFab.

[0087] In this tire 2, the RFID tag 60 is placed sufficiently away from the vicinity of the end of the flange Rf and the vicinity of the maximum width position PWs, where there is a risk of significant distortion occurring if the RFID tag 60 is present. In this tire 2, the presence of the RFID tag 60 is effectively prevented from contributing to an increase in distortion. This tire 2 effectively prevents damage caused by the presence of the RFID tag 60. Moreover, damage to the RFID tag 60 itself is also effectively prevented. The tire 2 maintains good durability despite the incorporation of the RFID tag 60. From this viewpoint, in the tire 2, in a standard ground contact state, it is preferable that the RFID tag 60 is located between the end PF of the turned-up portion 50 and the maximum width position PPs of the carcass 12 in the axial direction, and between the end PF of the turned-up portion 50 and the maximum width position PPs of the carcass 12 in the radial direction.

[0088] 1 is the shortest distance from the outer surface of the tire 2 to the RFID tag 60. The shortest distance t is the thickness of the rubber that covers the RFID tag 60.

[0089] In this tire 2, the shortest distance t is preferably 3.5 mm or more. This allows the RFID tag 60 to be covered with rubber having a sufficient thickness. In this tire 2, the presence of the RFID tag 60 is effectively prevented from contributing to an increase in distortion. In this tire 2, the occurrence of damage caused by the presence of the RFID tag 60 is effectively prevented. From this viewpoint, it is more preferable that the shortest distance t is 4.0 mm or more. Note that the upper limit of this shortest distance t varies depending on the position of the RFID tag 60, so a preferred upper limit of the shortest distance t is not set.

[0090] FIG. 8 shows the contour CL of the carcass 12 in a meridian section of the tire 2 in a normal state. The contour CL of the carcass 12 shown in Fig. 8 can be identified using, for example, a cross-sectional image of the tire 2 captured by the above-mentioned X-ray CT method. In this case, the cross-sectional image of the tire 2 captured by the X-ray CT method is imported into a computer-aided design (CAD), and the contour CL of the carcass 12 is identified on the CAD.

[0091] FIG. 9 shows a part of the meridian cross section of the tire 2. As shown in FIG. 9, the contour PL of the carcass 12 is represented by a line obtained by connecting the centers of the carcass cords 68 included in the ply body 48. FIG. 10 shows a modified example of the carcass 12 in which the carcass 12 is composed of two carcass plies 46 as an example of a case in which the carcass 12 is composed of a plurality of carcass plies 46. In this case, in the cross section shown in FIG. 10, the contour PL of the carcass 12 is represented by a line obtained by connecting the centers between the inner edge 68n of the carcass cord 68 included in the ply body 48 located on the inside and the outer edge 68g of the carcass cord 68 included in the ply body 48 located on the outside. Although not indicated by symbols, the elements located on both sides of the carcass cord 68 in FIGS. 9 and 10 are topping rubbers that cover the carcass cords 68.

[0092] 8, the position indicated by the symbol PE is the intersection point between the contour PL (hereinafter, case line PL) of the carcass 12 and the equatorial plane. The intersection point PE is the equator of the case line PL. The length indicated by the symbol CH is the radial distance from the bead base line to the equator PE. In the tire 2, the equator PE coincides with the radially outer end of the case line PL. The radial distance CH is also the cross-sectional height of the carcass 12.

[0093] In Fig. 8, the position indicated by the symbol PPb is the axially outer end of the case line PL in a normal state. In the tire 2 in a normal state, the case line PL has a maximum width at the axially outer end PPb. This axially outer end PPb is also called the maximum width position of the case line PL (or the maximum width position of the carcass 12). The length indicated by the symbol CW is the axial distance from the equatorial plane to the axially outer end PPb. Although not shown in Fig. 8, the outer end PA of the apex 38 is located radially inward of the axially outer end PPb.

[0094] In Fig. 8, the position indicated by the symbol ME is the radial outer end of the core body 36m. The solid line indicated by the symbol ML is a straight line that passes through the radial outer end ME and extends in the axial direction. The position indicated by the symbol PM is the intersection point between the straight line ML and the case line PL. The intersection point PM is a position on the case line PL that corresponds to the radial outer end ME of the core body 36m. The intersection point PM is the reference point of the case line PL.

[0095] In the tire 2, the case line PL is formed by combining a plurality of circular arcs and, if necessary, connecting the circular arcs with straight lines. The case line PL has an outwardly convex shape in the tread portion, an outwardly convex shape in the sidewall portion and the radially outer portion of the bead portion, and an inwardly concave shape in the radially inner portion of the bead portion. In the bead portion, there is an inflection point between the outwardly convex portion and the inwardly concave portion.

[0096] In the present invention, "outwardly bulging" means a shape curved from the inner surface side to the outer surface side of the tire, and "inwardly recessed" means a shape curved from the outer surface side to the inner surface side of the tire.

[0097] In this tire 2, the case line PL has a radially inner portion from the axially outer end PPb, specifically, a portion from the axially outer end PPb to the reference point PM, which has a curved portion 70 that bulges outward and a reverse curved portion 72 that dents inward. That is, in a meridian cross section of the tire 2 in a normal state, the contour of the carcass 12 has the curved portion 70 and the reverse curved portion 72 located radially inside the curved portion 70 at the radially inner portion of the maximum width position PPb of the carcass 12. The reverse curved portion 72 is located radially inside the curved portion 70 and is continuous with this curved portion 70. The boundary between the curved portion 70 and the reverse curved portion 72 is the inflection point described above. In Fig. 8, the position indicated by the symbol PV is the inflection point.

[0098] The curved portion 70 of the tire 2 shown in Fig. 8 is represented by a single circular arc. This circular arc has a center Ca on a straight line (solid line LPb in Fig. 8) that passes through the axially outer end PPb and extends in the axial direction, and includes the axially outer end PPb and an inflection point PV. The arrow indicated by the symbol R1 in Fig. 8 indicates the radius of this circular arc. Although not shown, in the tire 2, the curved portion 70 may be represented by an arc (hereinafter, arc a) having a center on the straight line LPb and including the axially outer end PPb, and an arc (hereinafter, arc b) tangent to the arc a and including the inflection point PV. In this case, the center of the arc b is located on the straight line passing through the center of the arc a and the tangent point between the arc a and the arc b. In the tire 2, the arc having a center on the straight line LPb and including the axially outer end PPb and the arc including the inflection point PV may be connected by one or more arcs. In this case, the curved portion 70 is represented by a plurality of arcs including the arc having a center on the straight line LPb and including the axially outer end PPb and the arc including the inflection point PV, and two adjacent arcs are configured to be in contact with each other. In either case, the curved portion 70 includes a circular arc that includes the inflection point PV. In the present invention, the circular arc that passes through this inflection point PV is the first circular arc. In the tire 2, a part or the entirety of the curved portion 70 is represented by a first circular arc passing through the inflection point PV.

[0099] In the tire 2 shown in Fig. 8, the reverse curved portion 72 is also represented by a single arc. This arc has a center Cb on a straight line (solid line LAB in Fig. 8) passing through the center Ca of the arc (first arc) representing the curved portion 70 and the inflection point PV, and includes the inflection point PV and a reference point PM. The arrow indicated by the symbol R2 in Fig. 8 indicates the radius of this arc. Although not shown, in the tire 2, the reverse curved portion 72 may be represented by an arc including the inflection point PV (hereinafter, arc c) and an arc tangent to the arc c and including the reference point PM (hereinafter, arc d). In this case, the center of the arc d is located on a straight line passing through the center of the arc c and the tangent point between the arc c and the arc d. In the tire 2, the arc including the inflection point PV and the arc including the reference point PM may be connected by one or more arcs. In this case, the reverse curved portion 72 is represented by a plurality of arcs including the arc including the inflection point PV and the arc including the reference point PM, and is configured so that two adjacent arcs are in contact with each other. In either case, the reverse curvature portion 72 includes a circular arc that includes the inflection point PV. In this disclosure, the circular arc that passes through this inflection point PV is the second circular arc.

[0100] When the configuration of the case line PL is unknown, the first arc representing the curved portion 70, the second arc representing the reverse curved portion 72, and the inflection point PV can be obtained as follows. The case line PL is identified based on a cross-sectional image of the tire in a normal state taken by the X-ray CT method. The axial outer end PPb of the case line PL is determined. An outwardly convex arc (hereinafter, outward arc) is drawn, the center of which is on a straight line LPb that passes through the axial outer end PPb and extends in the axial direction, and which includes the axial outer end PPb. By drawing the outward arc while changing the radius, an outward arc (hereinafter, first outward arc) that has a maximum overlap length with the case line PL from the axial outer end PPb is determined. If the first outward arc cannot represent the entire curved portion 70, another outward arc is drawn, the center of which is on a straight line that passes through the end of the first outward arc and the center of this first outward arc. By drawing the outward arc while changing the radius, an outward arc (hereinafter, second outward arc) that has a maximum overlap length with the case line PL from the end of the first outward arc is determined. The tracing of the case line PL by this outward arc is repeated until the case line PL cannot be traced by the outward arc. The end of the last drawn outward arc on the core body 36m side is identified as the inflection point PV, and this outward arc is identified as the first arc that includes the inflection point PV and represents a part or the entirety of the curved portion 70. An inwardly convex arc (hereinafter, referred to as an inward arc) is drawn on a straight line passing through the center of the first arc and the inflection point PV, and has a center on the opposite side of the inflection point PV from the center of the first arc, and includes the inflection point PV. By drawing the inward arc while changing the radius, an inward arc (hereinafter, referred to as a first inward arc) having a maximum overlap length with the case line PL from the inflection point PV is obtained. This first inward arc is specified as a second arc that includes the inflection point PV and represents a part or all of the reverse curved portion 72. If the entire reverse curved portion 72 cannot be drawn with the first inward arc, tracing by the inward arc is repeated until the last inward arc including the reference point PM is drawn.

[0101] In this tire 2, a part or the whole of the reverse curved portion 72 is represented by a second circular arc passing through the inflection point PV. The first circular arc representing a part or the whole of the curved portion 46 and the second circular arc representing a part or the whole of the reverse curved portion 72 are tangent to each other at the inflection point PV. The inflection point PV is located between the center of the first circular arc and the center of the second circular arc, and the center of the first circular arc, the inflection point PV, and the center of the second circular arc are located on the same straight line. 8, a first circular arc representing the curved portion 70 and a second circular arc representing the reverse curved portion 72 are in contact with each other at an inflection point PV. The inflection point PV is located between the center Ca of the first circular arc and the center Cb of the second circular arc, and the center Ca of the first circular arc, the inflection point PV, and the center Cb of the second circular arc are located on the same straight line LAB.

[0102] In tire 2, a particularly large load acts on the radially inner portion of the inflection point PV of the case line PL, and therefore this radially inner portion of the inflection point PV is an area where distortion due to the presence of a foreign object is likely to occur if such a foreign object is present.

[0103] 2, in this tire 2, the RFID tag 60 is located radially outward of the inflection point PV. This effectively prevents the presence of the RFID tag 60 from contributing to an increase in distortion. This tire 2 effectively prevents damage caused by the presence of the RFID tag 60. Moreover, damage to the RFID tag 60 itself is also effectively prevented. The tire 2 maintains good durability despite the incorporation of the RFID tag 60. From this viewpoint, it is preferable that the RFID tag 60 be located radially outward of the inflection point PV.

[0104] 8, the length indicated by the symbol X is the axial distance from the equatorial plane to the inflection point PV of the tire 2. The length indicated by the symbol Y is the radial distance from the bead base line to the inflection point PV.

[0105] In this tire 2, it is preferable that the ratio (X / CW) of the axial distance X from the equatorial plane to the inflection point PV to the axial distance CW from the equatorial plane to the axial outer end PPb is 70% or more and 85% or less, and the ratio (Y / CH) of the radial distance Y from the bead base line to the inflection point PV to the radial distance CH from the bead base line to the equator PE is 15% or more and 22% or less.

[0106] By setting the ratio (X / CW) to 70% or more and the ratio (Y / CH) to 15% or more, the inflection point PV is disposed at an appropriate distance from the core 36. The RFID tag 60 located radially outward of the inflection point PV is effectively prevented from contributing to an increase in distortion. In this tire 2, the occurrence of damage caused by the presence of the RFID tag 60 is effectively prevented. Moreover, the occurrence of damage to the RFID tag 60 itself is also effectively prevented. From this viewpoint, it is more preferable that the ratio (X / CW) is 75% or more and the ratio (Y / CH) is 17% or more. By setting the ratio (X / CW) to 85% or less and the ratio (Y / CH) to 22% or less, the inflection point PV is disposed at an appropriate distance from the maximum width position PPb. Deformation of the carcass 12 in the bead portion when the tire 2 is inflated is suppressed, and even in this case, the RFID tag 60 located radially outside the inflection point PV is effectively prevented from promoting an increase in distortion. In this tire 2, the occurrence of damage caused by the presence of the RFID tag 60 is effectively suppressed. Moreover, the occurrence of damage to the RFID tag 60 itself is also effectively suppressed. From this viewpoint, it is more preferable that the ratio (X / CW) is 80% or less and the ratio (Y / CH) is 20% or less.

[0107] In Fig. 8, solid line LV is a tangent to case line CL at inflection point PV. Solid line LT is a straight line including a straight line representing the contour of bottom surface 36msb of core body 36m in meridian cross section of tire 2. Angle θ is an angle between tangent line LV and straight line LT. In the present invention, this angle θ is an angle between tangent line LV to the contour of carcass 12 at inflection point PV and a straight line representing the contour of bottom surface 32mcb.

[0108] In the tire 2, the angle θ is preferably equal to or greater than 25 degrees and equal to or less than 30 degrees. By setting the angle θ to 25 degrees or more, collapse of the case line CL in the bead portion is effectively suppressed. Since the distortion caused by the action of the load is prevented from increasing, the RFID tag 60 located radially outside the inflection point PV is effectively prevented from contributing to the increase in distortion. In this tire 2, the occurrence of damage caused by the presence of the RFID tag 60 is effectively suppressed. Moreover, damage to the RFID tag 60 itself is effectively suppressed. From this viewpoint, it is more preferable that the angle θ is 26 degrees or more. Setting the angle θ to 30 degrees or less suppresses deformation of the carcass 12 in the bead portion when the tire 2 is inflated. Even in this case, the RFID tag 60 located radially outside the inflection point PV is effectively prevented from promoting an increase in distortion. In this tire 2, the occurrence of damage caused by the presence of the RFID tag 60 is effectively suppressed. Moreover, the occurrence of damage to the RFID tag 60 itself is also effectively suppressed. From this viewpoint, it is more preferable that the angle θ is 29 degrees or less.

[0109] In this tire 2, the tag member 26 is located radially outward of the end PF of the turned-up portion 50 and axially outward of the outer apex 42. The tag member 26 contacts the outer apex 42. The boundary between the tag member 26 and the outer apex 42 forms part of the outer surface of the outer apex 42. In other words, the boundary between the tag member 26 and the outer apex 42 forms part of the outer surface of the apex 38. In the tire 2, the RFID tag 60 is located between the outer end PG2 of the outer apex 42 and the end PF of the folded-back portion 50 in the radial direction. The RFID tag 60 of this tire 2 is disposed in a bead portion where the degree of bending is small. In this tire 2, the risk of damage to the RFID tag 60 is low. Since the outer apex 42, which is softer than the inner apex 40, is located axially inside the RFID tag 60, the presence of the RFID tag 60 is effectively prevented from promoting an increase in distortion. In this tire 2, the occurrence of damage caused by the presence of the RFID tag 60 is prevented. Moreover, the occurrence of damage to the RFID tag 60 itself is also prevented. In this tire 2, good durability is maintained despite the incorporation of the RFID tag 60. In this tire 2, the outer apex 42 is located between the carcass ply 46 and the RFID tag 60. The RFID tag 60 is disposed at a distance from the carcass ply 46, which includes a carcass cord that is a metal element. Since radio waves are less likely to be disturbed, a good communication environment is formed between the RFID tag 60 and a communication device (not shown). Data can be written to the RFID tag 60 and data recorded in the RFID tag 60 can be read accurately. From the viewpoint of maintaining good durability while forming a good communication environment and reducing the risk of damage to the RFID tag 60, it is preferable that the tag member 26 contacts the outer apex 42 radially outside the end PF of the folded-back portion 50, and the RFID tag 60 is located in the radial direction between the outer end PG2 of the outer apex 42 and the end PF of the folded-back portion 50. From the same viewpoint, it is more preferable that the RFID tag 60 is located in the radial direction between the outer end PG2 of the outer apex 42 and the outer end PB of the chafer 8.

[0110] In this tire 2, the inner end 26u of the tag member 26 is located radially outward of the outer end PB of the chafer 8. In this tire 2, the entire tag member 26 is disposed radially outward of the outer end PB of the chafer 8. Since the interference of the tag member 26 with the outer end PB of the chafer 8 is effectively suppressed, the outer end PB of the chafer 8 is effectively suppressed from waving (i.e., the occurrence of creases). The presence of the RFID tag 60 is effectively suppressed from promoting an increase in distortion. In this tire 2, the occurrence of damage caused by the presence of the RFID tag 60 is suppressed. Moreover, the occurrence of damage to the RFID tag 60 itself is also suppressed. In this tire 2, good durability is maintained despite the incorporation of the RFID tag 60. From this viewpoint, in this tire 2, it is preferable that the inner end 26u of the tag member 26 is located radially outward of the outer end PB of the chafer 8.

[0111] In this tire 2, the outer end 26s of the tag member 26 is located radially inward of the outer end PG2 of the outer apex 42. This effectively suppresses the effect of the tag member 26 on the deflection of the sidewall portion. Good durability and ride comfort are maintained in this tire 2. From this viewpoint, it is preferable that the outer end 26s of the tag member 26 is located radially inward of the outer end PG2 of the outer apex 42.

[0112] In this tire 2, it is more preferable that the inner end 26u of the tag member 26 is located radially outward of the outer end PB of the chafer 8, and the outer end 26s of the tag member 26 is located radially inward of the outer end PG2 of the outer apex 42. In this case, as shown in FIG 2, the entire tag member 26 is disposed between the outer end PG2 of the outer apex 42 and the outer end PB of the chafer 8.

[0113] As described above, the tag member 26 contacts the outer apex 42. As shown in Fig. 2, the tag member 26 is covered by the sidewall 6. The tag member 26 also contacts the sidewall 6. The tag member 26 is sandwiched between the outer apex 42 and the sidewall 6, between the outer end PG2 of the outer apex 42 and the outer end PB of the chafer 8. The tire 2 can improve the readability of the RFID tag 60 and reduce the risk of damage while suppressing the effect on durability. From this viewpoint, it is more preferable that the tag member 26 is sandwiched between the outer apex 42 and the sidewall 6 between the outer end PG2 of the outer apex 42 and the outer end PB of the chafer 8.

[0114] In this tire 2, the outer end PB of the chafer 8 is located radially outward of the inner end PS of the sidewall 6, and the sidewall 6 covers the outer end PB of the chafer 8. Since the outer end PB of the chafer 8 is covered by the sidewall 6, the strain acting on the outer end PB is effectively alleviated. In this tire 2, the chafer 8 is harder than the sidewall 6. Therefore, by covering the outer end PB of the chafer 8 with the sidewall 6, the strain acting on the outer end PB is more effectively alleviated. In this tire 2, the occurrence of damage caused by the presence of the RFID tag 60 is suppressed. Moreover, the occurrence of damage to the RFID tag 60 itself is also suppressed. In this tire 2, good durability is maintained despite the incorporation of the RFID tag 60. From this viewpoint, in this tire 2, it is preferable that the outer end PB of the chafer 8 is located radially outward of the inner end PS of the sidewall 6, and the sidewall 6 covers the outer end PB of the chafer 8.

[0115] 2 is the radial distance from the bead base line to the outer end PB of the chafer 8. The radial distance Rb1 is also called the radial height of the outer end PB of the chafer 8. 2 is the radial distance from the bead base line to the inner end PS of the sidewall 6. The radial distance K2 is also called the radial height of the inner end PS of the sidewall 6.

[0116] In the tire 2, the ratio (L1 / Rb1) of the radial height L1 of the outer end PG2 of the outer apex 42 to the radial height Rb1 of the outer end PB of the chafer 8 is preferably 1.08 or greater and 1.54 or less. Setting the ratio (L1 / Rb1) to 1.08 or greater ensures a space for arranging the tag member 26. In this tire 2, the tag member 26 can be arranged at a position where it is less likely to interfere with the outer end PB of the chafer 8. In this tire 2, the presence of the RFID tag 60 is effectively prevented from promoting an increase in distortion. From this viewpoint, it is more preferable that the ratio (L1 / Rb1) be 1.12 or greater. Setting the ratio (L1 / Rb1) to be equal to or less than 1.54 suppresses the effect of the outer apex 42 on the deflection of the tire 2. Good ride comfort is maintained in the tire 2. From this viewpoint, it is more preferable that the ratio (L1 / Rb1) be equal to or less than 1.42.

[0117] In the tire 2, the ratio (Rb1 / K2) of the radial height Rb1 of the outer end PB of the chafer 8 to the radial height K2 of the inner end PS of the sidewall 6 is preferably equal to or greater than 2.00 and equal to or less than 3.25. By setting the ratio (Rb1 / K2) to 2.00 or more, a sufficient joining area between the sidewall 6 and the chafer 8 can be secured. In this tire 2, the distortion acting on the outer end PB of the chafer 8 is more effectively alleviated. In this tire 2, the presence of the RFID tag 60 is effectively prevented from promoting an increase in distortion. From this viewpoint, it is more preferable that the ratio (Rb1 / K2) is 2.20 or more. Setting the ratio (Rb1 / K2) to 3.25 or less ensures a space for arranging the tag member 26. In this tire 2, the tag member 26 can be arranged at a position where it is less likely to interfere with the outer end PB of the chafer 8. Even in this case, the presence of the RFID tag 60 is effectively prevented from promoting an increase in distortion. From this viewpoint, it is more preferable that the ratio (Rb1 / K2) is 3.00 or less.

[0118] In this tire 2, the outer end PU of the inner apex 40 is located between the end PF of the folded-back portion 50 and the RFID tag 60 in the radial direction. As a result, the hard inner apex 40 effectively increases the rigidity of the bead portion. And the distortion acting on the RFID tag 60 is effectively reduced. The presence of the RFID tag 60 is effectively suppressed from promoting an increase in distortion. From this viewpoint, it is preferable that the outer end PU of the inner apex 40 is located between the end PF of the folded-back portion 50 and the RFID tag 60 in the radial direction. In this case, from the viewpoint of more effectively suppressing the presence of the RFID tag 60 from promoting an increase in distortion, it is more preferable that the outer end PU of the inner apex 40 is located between the end PF of the folded-back portion 50 and the RFID tag 60 in the radial direction, and further the outer end PU of the inner apex 40 is located between the end PF of the folded-back portion 50 and the outer end of the chafer 8 in the radial direction.

[0119] As is clear from the above description, according to the present invention, a heavy duty tire 2 capable of suppressing the occurrence of damage caused by the presence of an RFID tag 60 can be obtained. [Industrial Applicability]

[0120] The above-described technology capable of suppressing the occurrence of damage caused by the presence of an RFID tag can be applied to various types of tires. [Explanation of symbols]

[0121] 2. Tires 4. Tread 6. Sidewall 8. Chafer 10 Bead 12. Carcass 14. Cord reinforcement layer 20...Steel reinforcement layer 22...Interlayer strip 26 Tag member 36 cores 38. Apex 40···Inner apex 42. Outside apex 44···Edge strip 46···Carcass ply 48···Ply body 50... Folded part 52...Belt 54 Belt ply 56...Band 58...Full Band 60... RFID Tag 62 Protective body 64 Semiconductor chip 66 Antenna 68···Carcass cord 70... Curved section 72...Reverse curved part

Claims

1. A tire comprising: a pair of beads; a carcass spanning the pair of beads; a belt located radially outward of the carcass and including a number of parallel belt cords; a pair of sidewalls located axially outward of the carcass; a pair of chafers located radially inward of the sidewalls and in contact with a rim; and a tag member including an RFID tag, The bead includes a core and an apex located radially outward of the core, The carcass comprises a carcass ply; The carcass ply includes a ply body that spans between a pair of the beads, and a pair of turn-up portions that are connected to the ply body and turned up at the beads, The belt includes three or less radially arranged belt plies, The rim is a regular rim, The state in which the tire is mounted on the rim and the internal pressure of the tire is adjusted to a normal internal pressure is the normal state, A standard contact state is a state in which a load of 50% of a normal load is applied to the tire in the normal state and the tire is brought into contact with a flat surface. In the standard ground contact state, the RFID tag is located axially between an axially outer end of the rim and a maximum width position of the tire, and is located radially between a radially outer end of the rim and a maximum width position of the tire. Heavy duty tires.

2. In the standard grounding state, the RFID tag is located between an end of the folded-up portion and a maximum width position of the carcass in the axial direction, and is located between the end of the folded-up portion and a maximum width position of the carcass in the radial direction.

2. A heavy duty tire according to claim 1.

3. The shortest distance from the outer surface of the tire to the RFID tag is 3.5 mm or more.

3. A heavy duty tire according to claim 1 or 2.

4. In the meridian cross section of the tire in the normal state, the contour of the carcass includes, at a radially inner portion of a maximum width position of the carcass, a curved portion that bulges outward, and a reverse curved portion that is located radially inner of the curved portion and recessed inward, the reverse curved portion is continuous with the curved portion, The boundary between the curved portion and the reverse curved portion is an inflection point, A part or the whole of the curved portion is represented by a first circular arc including the inflection point, A part or the whole of the reverse curved portion is represented by a second circular arc including the inflection point, the first arc and the second arc are tangent to each other at the inflection point; The RFID tag is located radially outward of the inflection point.

3. A heavy duty tire according to claim 1 or 2.

5. The apex includes an inner apex located radially outward of the core, and an outer apex located radially outward of the inner apex, The outer apex is softer than the inner apex, the tag member contacts the outer apex at a radially outer side of an end of the folded portion, The RFID tag is located between an outer end of the outer apex and an end of the folded-back portion in a radial direction.

3. A heavy duty tire according to claim 1 or 2.

6. the tag member is positioned between the outer end of the outer apex and the sidewall, between the outer end of the outer apex and the outer end of the chafer; A heavy duty tire according to claim 5.

7. an outer end of the chafer is located radially outward of an inner end of the sidewall; The sidewall covers the outer end of the chafer. A heavy duty tire according to claim 5.

8. the tag member is a plate-like member in which the RFID tag is covered with a crosslinked rubber, The thickness of the tag member is 1.0 mm or more and 2.5 mm or less.

3. A heavy duty tire according to claim 1 or 2.

9. The number of the belt plies included in the belt is two or less.

3. A heavy duty tire according to claim 1 or 2.

10. A band is provided, the band being located radially outside the carcass and including a spirally wound band cord. The band includes a full band having opposite ends across an equator plane, The belt ply and the full band are aligned in a radial direction.

3. A heavy duty tire according to claim 1 or 2.

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