JP2024055437A - Heavy Duty Tires - Google Patents

Abstract

[Problem] To provide a heavy-duty tire 2 capable of forming a good communication environment and reducing the risk of damage to an RFID tag. [Solution] The tire 2 comprises a pair of beads 10, a carcass 12, and a tag member 26 including an RFID tag 60. The carcass 12 comprises a carcass ply 46 including a large number of parallel steel cords. The carcass ply 46 comprises a ply body 48 and a pair of turned-up portions 50. An end PF of the turned-up portion 50 is located radially inside an outer end PA of an apex 38 of the bead 10. The tag member 26 is laminated on an outer surface 38g of the apex 38, and the RFID tag 60 is located radially between the end PF of the turned-up portion 50 and the outer end PA of the apex 38. The ratio (N/G) of the radial height N of the turned-up portion 50 to the flange height G of the rim R is 1.2 or more and 2.5 or less. [Selected Figure] Figure 2

Description

The present invention relates to a heavy-duty tire. In particular, the present invention relates to a tubeless-type heavy-duty tire that is mounted on a 5-degree tapered rim.

It has been proposed to embed an RFID (Radio Frequency Identification) tag in a tire to manage data such as tire manufacturing management, customer information, and driving history. Various studies are being conducted on technology for embedding an RFID tag in a tire (for example, see Patent Document 1 below).

JP 2020-185975 A

To prevent damage, the RFID tag is placed in a part of the tire that is least likely to bend. In the case of heavy-duty tires, the bead portion has high rigidity. For heavy-duty tires, the bead portion is being considered as a location for placing the RFID tag.

When a tire is mounted on a rim, the bead portion comes into contact with the rim. The part of the bead portion that is inside the contact end with the rim flange is constrained by the rim, but the part outside the contact end is free.

Heavy duty tires that are mounted on 5-degree tapered rims are available in with-tube and tubeless types.
The flange height of a rim for a tubeless type tire (hereinafter also referred to as a tubeless tire) is lower than the flange height of a rim for a with-tube type tire (hereinafter also referred to as a tube tire).
In the bead portion of a tubeless tire, the area in which movement is restricted by the rim is smaller than that of the bead portion of a tube tire. When the tire is mounted on the rim, the bead portion of a tubeless tire is more likely to deform than the bead portion of a tube tire. In a tubeless tire, distortion is more likely to concentrate on the RFID tag than in a tube tire.
Since concentrated distortion increases the risk of damage, when placing an RFID tag in the bead of a tubeless tire, the position of the RFID tag must be determined taking into account that the bead is easily deformed. There is a demand for placement of RFID tags that are compatible with tubeless tires.

The tire includes a carcass that spans between a pair of beads. The carcass includes a carcass ply. The carcass ply is folded up at the bead.
The carcass ply of a heavy duty tire typically includes a number of parallel steel cords. The turn-up portion of the carcass ply is positioned so that its end overlaps the apex of the bead. The bead portion of a heavy duty tire includes metal elements such as steel cords.

The communication environment involving RFID tags is affected by metal elements, and placing an RFID tag near a metal element may cause radio wave disturbances, making it difficult to accurately read the data recorded in the RFID tag.
When placing an RFID tag in a bead portion, it is necessary to consider not only the durability of the tire and the RFID tag, but also the readability of the RFID tag in the tire.

The present invention has been made in consideration of these circumstances. The object of the present invention is to provide a heavy-duty tire that can achieve the creation of a good communication environment and the reduction of the risk of damage to the RFID tag. In particular, the object of the present invention is to provide a tubeless type heavy-duty tire that can be mounted on a 5-degree tapered rim and can achieve the creation of a good communication environment and the reduction of the risk of damage to the RFID tag.

The heavy-duty tire according to the present invention is a tubeless type heavy-duty tire that is assembled to a rim, and the rim is a 5-degree tapered rim. The tire includes a pair of beads, a carcass that spans between the pair of beads, and a tag member that includes an RFID tag. The bead includes a core and an apex located radially outside the core. The carcass includes a carcass ply that includes a large number of parallel steel cords. The carcass ply includes a ply body that spans between the pair of beads, and a pair of turn-up portions that are connected to the ply body and turned up at the beads. The ends of the turn-up portions are located radially inside the outer end of the apex. The tag member is laminated on the outer surface of the apex. The RFID tag is located radially between the end of the turn-up portion and the outer end of the apex. The ratio of the radial height of the turn-up portion to the flange height of the rim is 1.2 to 2.5.

According to the present invention, a heavy-duty tire is obtained that can achieve the creation of a good communication environment and the reduction of the risk of damage to the RFID tag. In particular, according to the present invention, a heavy-duty tubeless tire that is mounted on a 5-degree tapered rim is obtained that can achieve the creation of a good communication environment and the reduction of the risk of damage to the RFID tag.

1 is a cross-sectional view showing a portion of a heavy duty tire according to one embodiment of the present invention. FIG. 2 is a cross-sectional view of a portion of the tire of FIG. 1 . FIG. 2 is a cross-sectional view of a portion of a rim for the tire of FIG. 1. FIG. 5 is a cross-sectional view taken along line VV in FIG. 4.

The present invention will now be described in detail based on a preferred embodiment, with reference to the drawings as appropriate.

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. A tire mounted on a rim is also called a tire-rim assembly. A tire-rim assembly includes a rim and a tire mounted on the rim.

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

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 the meridian section of the tire, which cannot be measured when the tire is mounted on a regular rim, are measured on the cut surface of the tire obtained by cutting the tire along a plane including the axis of rotation. In this measurement, the tire is set so that the distance between the left and right beads is the same as the distance between the beads of the tire mounted on a regular rim. The tire configuration that cannot be confirmed when the tire is mounted on a regular rim is confirmed on the aforementioned cut surface.

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.

Normal internal 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 internal pressures.

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.

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.

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 strain = 10%
Dynamic strain = ±1%
Frequency = 10Hz
Mode = Extension mode Temperature = 70°C
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 the test piece cannot be sampled 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 complex modulus at 70°C.

[Overview of the embodiment of the present invention]
[Configuration 1]
A heavy-duty tire according to one embodiment of the present invention is a tubeless type heavy-duty tire that is assembled to a rim, the rim being a 5 degree tapered rim, the tire comprising: a pair of beads, a carcass spanning between the pair of beads, and a tag member including an RFID tag, the beads comprising a core and an apex located radially outside the core, the carcass comprising a carcass ply including a large number of parallel steel cords, the carcass ply comprising a ply body spanning between the pair of beads, and a pair of turn-up portions that are connected to the ply body and folded back at the beads, an end of the turn-up portion is located radially inside an outer end of the apex, the tag member is laminated on the outer surface of the apex, the RFID tag is located radially between an end of the turn-up portion and the outer end of the apex, and a ratio of the radial height of the turn-up portion to the flange height of the rim is 1.2 or more and 2.5 or less.

By arranging the tire in this manner, the RFID tag is placed in a portion of the bead that is least curved, and the risk of the RFID tag being damaged or being damaged originating from the RFID tag is low.
In this tire, the apex is located between the carcass ply and the RFID tag. The RFID tag is disposed at a distance from the carcass ply, which includes the carcass cord, which is a metal element. Since radio wave disturbance is unlikely to occur, a good communication environment is formed between the RFID tag and communication equipment. Data can be written to the RFID tag and data recorded in the RFID tag can be read accurately.
Moreover, concentration of strain at the ends of the turned-up portions is effectively suppressed in this tire 2. In this tire 2, good durability is maintained.
This tire is a tubeless tire and has bead portions that are more easily deformed than the bead portions of tube tires, but it is still possible to create a good communication environment and reduce the risk of damage to the RFID tag.

[Configuration 2]
Preferably, in the tire described in the above-mentioned [Configuration 1], the apex has an edge strip constituting a part of its outer surface, the outer end of the edge strip is located radially inward of the outer end of the apex, the end of the folded-back portion is laminated to the edge strip, and the RFID tag is positioned away from the outer end of the edge strip.
By arranging the tire in this way, the RFID tag is prevented from interfering with the outer end of the edge strip, and the concentration of strain on the RFID tag is effectively suppressed. This tire can effectively reduce the risk of damage to the RFID tag.

[Configuration 3]
Preferably, in the tire according to the above-mentioned [Configuration 1] or [Configuration 2], a ratio of a radial height of the apex to a radial height of the turned-up portion is 1.50 or greater and 2.50 or less.
By arranging the tire in this manner, a space for arranging the tag member is secured. The RFID tag can be arranged taking into consideration the position of the outer end of the edge strip. This tire reduces the risk of damage to the RFID tag.

[Configuration 4]
Preferably, the tire according to any one of the above-mentioned [Configuration 1] to [Configuration 3] further comprises a pair of chafers in contact with the rim, and an outer end of the tag member is located radially outward of the outer ends of the chafers.
By arranging the tire in this manner, interference between the outer end of the chafer and the tag member is suppressed compared to when the outer end of the tag member is located radially inside the outer end of the chafer. In this tire, creases that affect durability and appearance quality are less likely to occur.

[Configuration 5]
Preferably, the tire according to any one of the above-mentioned [Configuration 1] to [Configuration 4] further comprises a pair of steel reinforcing layers folded back at the bead and including a large number of parallel steel cords, the steel reinforcing layers including an inner end of the steel reinforcing layer and an inner portion located axially inside the ply body, and an outer portion including an outer end of the steel reinforcing layer and located axially outside the turned-up portion, and a ratio of a radial height of the outer portion to a radial height of the turned-up portion is 0.50 or more and 0.95 or less.
By arranging the tire in this manner, the concentration of strain caused by the outer ends of the steel reinforcing layers being close to the ends of the turned-up portions is effectively suppressed, and the tire maintains good durability.

[Details of the embodiment of the present invention]
1 shows a portion of a heavy duty tire 2 (hereinafter, 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.

Fig. 1 shows a part of a cross section (hereinafter, meridian cross section) of the tire 2 taken 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.
Fig. 2 shows a part of the cross section shown in Fig. 1. Fig. 2 shows a bead portion B of a tire 2. In Figs. 1 and 2, the tire 2 is mounted on a rim R (a regular rim).

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

3 shows a part of a cross section of the rim R. The rim R includes a seat Rs and a flange Rf. The bead portion B is placed on the seat Rs and pressed against the flange Rf.
As shown in Fig. 3, the sheet Rs is inclined with respect to the axial direction. The sheet Rs tapers inward in the axial direction.
The straight line indicated by the reference character TL represents the surface of the sheet Rs on which the bead portion B is placed. The reference character ABL represents a straight line extending in the axial direction. The reference character θ represents the angle between the straight lines TL and ABL.
The rim R on which the tire 2 is mounted is a 5-degree tapered rim. A 5-degree tapered rim refers to a rim in which the angle θ in FIG. 3 is set to 5 degrees±1 degree.

This tire 2 is a tubeless type heavy duty tire mounted on a 5-degree tapered rim. This 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 belt 14, a pair of cushion layers 16, a pair of steel reinforcing layers 18, a pair of interlayer strips 20, an inner liner 22, an insulation 24, and a tag member 26.

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. Grooves 30 are formed in the tread 4.
The tread 4 includes a base portion 32 and a cap portion 34 located radially outward of the base portion 32 and covering the entire 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.

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 the 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 in a tire 2 in a normal state is the section height of the tire 2 (see JATMA, etc.).

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 inner end PS of the sidewall 6 is included in the outer surface of the tire 2.
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.

The position indicated by the reference symbol PW is the axially outer end (hereinafter, outer end PW) of the tire 2. When the outer surface has decoration such as patterns or letters, the outer end PW is specified 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.
The axial distance from a first outer end PW to a second outer end PW (not shown) obtained in the tire 2 in a normal state is the section width of the tire 2 (see JATMA, etc.).

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

1, the position indicated by the symbol FG is the radial outer end of the rim R. The length indicated by the symbol G is the radial distance from the bead base line to the radial outer end FG of the rim R. The radial distance G is also called the flange height.
In the tire 2 in a normal state, the ratio (G/H) of the flange height G to the radial height H of the maximum width position PW is equal to or greater than 0.15 and is equal to or less than 0.25.

Each chafer 8 is located radially inward of 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 outer end PB of the chafer 8 is located radially outward of the inner end PS of the sidewall 6. The outer end PB of the chafer 8 is covered by the sidewall 6.
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.

2 is the radial distance from the bead base line to the outer end PB of the chafer 8. The radial distance R1 is also called the radial height of the chafer 8.
In the tire 2, the ratio (R1/N) of the radial height R1 of the chafer 8 to the radial height N of a turn-up portion 50 described later is set in the range of 0.70 to 1.50.

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

The core 36 extends in the circumferential direction. The core 36 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 36w wound in the circumferential direction. The cross-sectional shape of the core body 36m is arranged by regularly winding the wire 36w. As a result, in the cross section of the core body 36m, cross-sectional units consisting of cross sections of a plurality of wires 36w arranged in parallel in the approximately axial direction are stacked in multiple 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 quadrangular cross-sectional shape.
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 made 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.

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 inward of the maximum width position PW. The outer end PA is located radially outward of the outer end PB of the chafer 8.
The apex 38 includes an inner apex 40 , an outer apex 42 , and an edge strip 44 .

The inner apex 40 is located radially outward of the core 36. The inner apex 40 tapers outward. An outer end PU of the inner apex 40 is located radially inward of an outer end PA of the apex 38 and is included in an inner surface 38n of the apex 38. The inner apex 40 constitutes a part of the inner surface 38n of the apex 38.
The inner apex 40 is made of a hard crosslinked rubber. The inner apex 40 has a complex elastic modulus of 60 MPa or more and 90 MPa or less.

The outer apex 42 is located radially outward of the inner apex 40. The outer apex 42 is located axially outward of the inner apex 40. The outer apex 42 tapers toward the outer end PG1 and tapers toward the inner end PG2.
The outer end PG1 of the outer apex 42 is also the outer end PA of the apex 38. The outer end PG1 is located radially outward of the outer end PU of the inner apex 40.
An inner end PG2 of the outer apex 42 is located radially inward of the radially outer end FG of the rim R, and is included in the outer side surface 38g of the apex 38. The outer apex 42 constitutes a part of the outer side surface 38g of the apex 38.
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.

2 is the radial distance from the bead base line to the outer end PG1 of the outer apex 42. The radial distance L1 is also referred to as the radial height of the outer end PG1 of the outer apex 42. As described above, the outer end PG1 of the outer apex 42 is also the outer end PA of the apex 38. This radial distance L1 is also referred to as the radial height of the apex 38.
The length indicated by the symbol L2 is the radial distance from the bead base line to the outer end PU of the inner apex 40. The radial distance L2 is also called the radial height of the inner apex 40.

In this tire 2, the ratio (L1/H) of the radial height L1 of the apex 38 to the radial height H of the maximum width position PW is adjusted to a range of 0.55 to 0.95 in order to achieve a good balance between the rigidity of the bead portion B and the flexure of the tire 2. From the same perspective, the ratio (L2/L1) of the radial height L2 of the inner apex 40 to the radial height L1 of the apex 38 is appropriately adjusted to a range of 0.70 to 0.90 inclusive.

The edge strip 44 is located axially outboard of the outer apex 42. An outer end 44g of the edge strip 44 is located radially inboard of the outer end PG1 of the outer apex 42, in other words, the outer end PA of the apex 38. An inner end 44n of the edge strip 44 is located radially outboard of the inner end PG2 of the outer apex 42. The edge strip 44 constitutes a part of the outer surface 38g of the apex 38 between the outer end PG1 and the inner end PG2 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.

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, i.e., between the first bead 10 and the second bead 10 of the pair of beads 10. The carcass 12 of this tire 2 has a radial structure.

The carcass 12 has at least one carcass ply 46. The carcass 12 of this tire 2 consists of one carcass ply 46. The carcass ply 46 is folded back at the bead 10.

The carcass ply 46 includes a ply body 48 and a pair of turn-up portions 50. The ply body 48 spans between a pair of beads 10. Each turn-up portion 50 is continuous with the ply body 48 and is turned up at the bead 10. The turn-up portions 50 of the tire 2 are turned up at the bead 10 from the inside toward the outside in the axial direction.
The end PF of the turn-up portion 50 is located radially inward of the outer end PB of the chafer 8. As described above, the outer end PA of the apex 38 is located radially outward of the outer end PB of the chafer 8. The end PF of the turn-up portion 50 is located radially inward of the outer end PA of the apex 38.
The apex 38 is laminated to the ply body 48 at its inner surface 38n. The turnup portion 50 is laminated to the outer surface 38g of the apex 38. The bead 10 is located between the ply body 48 and the turnup portion 50.

2, the end PF of the folded portion 50 is laminated to the edge strip 44. The end PF of the folded portion 50 is located radially inward of the outer end 44g of the edge strip 44 and radially outward of the inner end 44n of the edge strip 44. In other words, the end PF of the folded portion 50 is located between the outer end 44g and the inner end 44n of the edge strip 44. The edge strip 44 suppresses the concentration of strain at the end PF of the folded portion 50.

Although not shown, the carcass ply 46 includes a number of carcass cords arranged in parallel. These carcass cords are covered with topping rubber. Each carcass cord intersects with the equatorial plane. Steel cords are used for the carcass cords of this tire 2. The carcass ply 46 includes a number of steel cords arranged in parallel.

The length indicated by the symbol N in FIG. 2 is the radial distance from the bead baseline to the end PF of the turn-up portion 50. The radial distance N is also called the radial height of the turn-up portion 50.

The belt 14 includes a plurality of belt plies 52 arranged in the radial direction. The belt 14 of the tire 2 includes three belt plies 52. The three belt plies 52 are a first belt ply 52A, a second belt ply 52B, and a third belt ply 52C. Of the three belt plies 52, the first belt ply 52A is located at the innermost position in the radial direction.
In the tire 2, the second belt ply 52B has the widest width, and the first belt ply 52A has the narrowest width.

Although not shown, each belt ply 52 includes a number of parallel belt cords. Each belt cord is inclined with respect to the equatorial plane. Steel cords are used for the belt cords of this tire 2.

Each cushion layer 16 is located at the end of the belt 14, between the belt 14 and the carcass 12. The cushion layer 16 is made of soft crosslinked rubber.

Each steel reinforcing layer 18 is located in a bead portion B. The steel reinforcing layer 18 is located between the chafer 8 and the carcass 12. The steel reinforcing layer 18 is turned up at the bead 10. The steel reinforcing layer 18 is disposed so as to wrap the radially inner portion of the bead 10 from the radially inner side of the turned up portion 52.
The steel reinforcing layer 18 has an inner portion 54 and an outer portion 56. The inner portion 54 is axially inward of the ply body 48. The inner portion 54 includes an inner end 18n of the steel reinforcing layer 18. The outer portion 56 is axially outward of the turnup portion 50. The outer portion 56 includes an outer end 18g of the steel reinforcing layer 18. The portion of the steel reinforcing layer 18 between the inner portion 54 and the outer portion 56 and radially inward of the bead 10 is also referred to as a curved portion 58.

Although not shown, the steel reinforcing layer 18 includes a number of parallel filler cords. These filler cords are covered with topping rubber. Each filler cord is inclined relative to the radial direction. Steel cords are used for the filler cords of this tire 2. The steel reinforcing layer 18 includes a number of parallel steel cords.

The outer end 18g of the steel reinforcing layer 18 is located radially inside the inner end 18n. The end PF of the folded portion 50 is located radially between the outer end 18g and the inner end 18n of the steel reinforcing layer 18. The inner end 18n of the steel reinforcing layer 18 is located radially inside the outer end PU of the inner apex 40.

Each interlaminar strip 20 is axially located between the chafer 8 and the apex 38 of the bead 10. The interlaminar strips 20 cover the end PF of the turnup portion 50 and the outer end 18g of the steel reinforcing layer 18.
The interlayer strip 20 contacts the apex 38 at a radially outer side of the end PF of the turned-up portion 50. In other words, the contact surface between the interlayer strip 20 and the apex 38 forms a part of the outer surface of the apex 38.
The interlayer strip 20 contacts the chafer 8 radially outside the outer end 18g of the steel reinforcing layer 18. In other words, the contact surface between the interlayer strip 20 and the chafer 8 constitutes a part of the inner surface of the chafer 8.
The interlayer strip 20 is made of a crosslinked rubber. The interlayer strip 20 is harder than the sidewall 6 and softer than the chafer 8. The complex elastic modulus of the interlayer strip 20 is 7.0 MPa or more and 12 MPa or less.

The inner liner 22 is located inside the carcass 12. The inner liner 22 is joined to the inner surface of the carcass 12 via insulation 24 made of crosslinked rubber. The inner liner 22 constitutes the inner surface of the tire 2. The inner liner 22 is made of crosslinked rubber with excellent air barrier properties.

The tag member 26 is located axially outside the bead 10. In this tire 2, the tag member 26 is provided only on the side of the first sidewall 6. The tag member 26 may be provided on both the side of the first sidewall 6 and the side of the second sidewall 6 (not shown). From the viewpoint of reducing the risk of damage, it is preferable that the tag member 26 is provided on the side of the first sidewall 6 of the pair of sidewalls 6.

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. 1, the tag member 26 is disposed in the tire 2 such that a first end 26s in the width direction is located on the radially outer side of the tire 2 and a second end 26u is located on the inner side. In the tire 2, the first end 26s is also called the outer end, and the second end 26u is also called the inner end.

The tag member 26 includes an RFID tag 60. In Fig. 4, the RFID tag 60 is shown by a solid line for convenience 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 approximately the same rigidity as the outer apex 42.
In the tire 2, consideration is given to the formation of a good communication environment, and 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.

Although we will not go into detail, the RFID tag 60 is a small, lightweight electronic component consisting of a semiconductor chip 64 that integrates a transmitting/receiving circuit, a control circuit, 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.

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 creating 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.

2 , the position indicated by the symbol TU is the radial inner end of the RFID tag 60. The radial inner end of the RFID tag 60 (hereinafter, the inner end TU of the RFID tag 60) is represented by the radial inner end of the semiconductor chip 64. The position indicated by the symbol TS is the radial outer end of the RFID tag 60. The radial outer end of the RFID tag 60 (hereinafter, the outer end TS of the RFID tag 60) is represented by the radial outer end of the semiconductor chip 64.
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.

As described above, the tire 2 is a tubeless type heavy duty tire mounted on a 5-degree tapered rim. Although not described in detail, the flange height G of the rim R applied to the tire 2 is lower than the flange height of a rim for a with-tube type tire (hereinafter also referred to as a tube tire).
In the bead portion B of the tire 2, the area in which movement is restricted by the rim R is smaller than that of the bead portion of a tube tire. When the tire 2 is mounted on the rim R, the bead portion B of the tire 2 is more easily deformed than the bead portion of a tube tire. In the tire 2, there is a higher risk of the RFID tag 60 being damaged or damage originating from the RFID tag 60 occurring, compared to a tube tire.

However, in this tire 2, the tag member 26 is laminated on the outer surface 38g of the apex 38. The RFID tag 60 is located between the end PF of the folded-back portion 50 and the outer end PA of the apex 38 in the radial direction.
In this tire 2, the RFID tag 60 is disposed in a portion that is particularly small in bending of the bead portion B. In this tire 2, the risk that the RFID tag 60 will be damaged or that damage originating from the RFID tag 60 will occur is low.
In this tire 2, the apex 38 (specifically, 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.

Moreover, in the tire 2, the ratio (N/G) of the radial height N of the folded-back portion 50 to the flange height G of the rim R is equal to or greater than 1.2 and equal to or less than 2.5.
Since the ratio (N/G) is 2.5 or less, it is possible to effectively suppress the concentration of strain at the end PF of the turn-up portion 50. In the tire 2, good durability is maintained.
Since the ratio (N/G) is 1.2 or more, the folded portion 50 can effectively contribute to ensuring the rigidity of the bead portion B.

This tire 2 is a tubeless tire and has a bead portion B that is more easily deformed than the bead portion of a tube tire. Nevertheless, this tire 2 can achieve the creation of a good communication environment and a reduced risk of damage to the RFID tag.

2, the RFID tag 60 is disposed away from the end PF of the folded portion 50 toward the tread 4. This prevents the RFID tag 60 from interfering with the end PF of the folded portion 50. Therefore, the concentration of strain on the RFID tag 60 is effectively suppressed. This tire 2 can effectively reduce the risk of damage to the RFID tag 60. Although the folded portion 50 includes a steel cord, the adverse effect of the folded portion 50 on the communication environment is suppressed. A good communication environment is formed between the RFID tag 60 and a communication device (not shown). From this viewpoint, it is preferable that the RFID tag 60 is disposed away from the end PF of the folded portion 50 toward the tread 4. In this case, it is more preferable that the RFID tag 60 is disposed 5 mm or more away from the end PF of the folded portion 50. In other words, it is more preferable that the distance from the end PF of the folded portion 50 to the RFID tag 60 is 5 mm or more.

As described above, the outer end PA of the apex 38 is located radially inward of the maximum width position PW. The RFID tag 60 is located radially between the end PF of the folded-back portion 50 and the outer end PA of the apex 38. The RFID tag 60 is located radially inward of the maximum width position PW.
In this tire 2, the RFID tag 60 is effectively disposed in a portion of the bead portion B that is particularly small in degree of bending. In this tire 2, the risk of the RFID tag 60 being damaged or of damage originating from the RFID tag 60 is effectively reduced. From this viewpoint, the RFID tag 60 is preferably positioned radially inward of the maximum width position PW.

As described above, the end PF of the folded portion 50 is laminated on the edge strip 44. As shown in FIG. 2, the RFID tag 60 is located radially outward of the outer end 44g of the edge strip 44. In other words, the RFID tag 60 is disposed away from the outer end 44g of the edge strip 44 toward the tread 4. The RFID tag 60 is prevented from interfering with the outer end 44g of the edge strip 44. The edge strip 44 is softer than the chafer 8 and harder than the outer apex 42. However, by disposing the RFID tag 60 away from the outer end 44g, the concentration of strain on the RFID tag 60 is effectively suppressed. This tire 2 can effectively reduce the risk of damage to the RFID tag 60. From this viewpoint, it is preferable that the RFID tag 60 is disposed away from the outer end 44g of the edge strip 44. In this case, it is more preferable that the RFID tag 60 is disposed 5 mm or more away from the outer end 44g of the edge strip 44. In other words, the distance from the outer end 44g of the edge strip 44 to the RFID tag 60 is preferably 5 mm or more.
In this tire 2, the position of the RFID tag 60 does not have to coincide with the position of the outer end 44g of the edge strip 44 in the radial direction, and the RFID tag 60 may be disposed away from the outer end 44g toward the bead 10. In this case, too, the distance from the outer end 44g of the edge strip 44 to the RFID tag 60 is preferably 5 mm or more.

In the tire 2, the ratio (L1/N) of the radial height L1 of the apex 38 to the radial height N of the turned-up portion 50 is preferably 1.50 or greater and 2.50 or less.
Setting the ratio (L1/N) to 1.50 or more ensures a space for arranging the tag member 26. In this tire 2, the RFID tag 60 can be arranged in consideration of the position of the outer end 44g of the edge strip 44. In this tire 2, the risk of damage to the RFID tag 60 can be reduced.
By setting the ratio (L1/N) to 2.50 or less, the folded-back portion 50 can effectively contribute to ensuring the rigidity of the bead portion B.

The outer end 44g of the edge strip 44 is located radially outside the end PF of the folded portion 50. As described above, when the RFID tag 60 is placed away from the outer end 44g toward the bead 10, the RFID tag 60 is placed between the outer end 44g and the end PF of the folded portion 50. In this case, from the viewpoint of securing the placement space of the tag member 26 and reducing the risk of damage to the RFID tag 60, it is preferable that the outer end 44g of the edge strip 44 is placed at a position 5 mm or more away from the end PF of the folded portion 50 toward the tread 4. In other words, it is preferable that the distance from the end PF of the folded portion 50 to the outer end 44g of the edge strip 44 is 5 mm or more. When the RFID tag 60 is placed away from the outer end 44g toward the tread 4, it is preferable that the distance from the end PF of the folded portion 50 to the outer end 44g of the edge strip 44 is 15 mm or less from the viewpoint of securing the placement space of the tag member 26.

As described above, in this tire 2, the RFID tag 60 is located radially between the end PF of the folded portion 50 and the outer end PA of the apex 38. From the viewpoint of forming a better communication environment and effectively reducing the risk of damage to the RFID tag 60, it is more preferable that the RFID tag 60 be located radially between the outer end 44g of the edge strip 44 and the outer end PA of the apex 38.

The outer end PB of the chafer 8 is located axially outward of the bead 10. The chafer 8 is an element that extends radially outward from the rim R side. The outer end PB of the chafer 8 is a location where waviness called a crease is likely to occur during the manufacture of the tire 2. Since the tag member 26 is positioned near the outer end PB of the chafer 8, there is concern that a crease may occur depending on the degree of interference between the outer end PB of the chafer 8 and the tag member 26.

In this tire 2, the outer end 26s of the tag member 26 is located radially outside the outer end PB of the chafer 8. In this tire 2, interference between the outer end PB of the chafer 8 and the tag member 26 is suppressed compared to when the outer end 26s of the tag member 26 is located radially inside the outer end PB of the chafer 8 (i.e., when the entire tag member 26 is covered by the chafer 8). In this tire 2, creases that affect durability and appearance quality are less likely to occur. From this perspective, it is preferable that the outer end 26s of the tag member 26 is located radially outside the outer end PB of the chafer 8.

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. This positions the entire tag member 26 radially outward of the outer end PB of the chafer 8. Interference of the tag member 26 with the outer end PB of the chafer 8 is effectively suppressed. In this tire 2, the occurrence of creases is effectively suppressed. 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.

In this tire 2, the outer end 26s of the tag member 26 is located radially inward of the outer end PA of the apex 38. This effectively suppresses the effect of the tag member 26 on the deflection of the sidewall portion. In this tire 2, good durability and ride comfort are maintained. From this perspective, it is preferable that the outer end 26s of the tag member 26 is located radially inward of the outer end PA of the apex 38.

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 PA of the apex 38. In this case, as shown in FIG. 2, the entire tag member 26 is disposed between the outer end PA of the apex 38 and the outer end PB of the chafer 8.

In FIG. 2, the length indicated by the letter O is the radial distance from the bead baseline to the outer end 18g of the steel reinforcing layer 18. The radial distance O is also referred to as the radial height of the outer portion 56 of the steel reinforcing layer 18.

In the tire 2, the ratio (O/N) of the radial height O of the outer portion 56 to the radial height N of the turned-up portion 50 is preferably 0.50 or greater and 0.95 or less.
Setting the ratio (O/N) to 0.95 or less effectively suppresses concentration of strain caused by the outer end 18g of the steel reinforcing layer 18 being close to the end PF of the folded-back portion 50. In this tire 2, good durability is maintained.
By setting the ratio (O/N) to 0.50 or more, the outer portion 56 of the steel reinforcing layer 18 can effectively contribute to ensuring the rigidity of the bead portion B.

As is clear from the above description, the present invention provides a heavy-duty tire that can create a good communication environment and reduce the risk of damage to the RFID tag. In particular, the present invention provides a heavy-duty tire of the tubeless type that is mounted on a 5-degree tapered rim and can create a good communication environment and reduce the risk of damage to the RFID tag.

The technology described above, which can create a good communication environment and reduce the risk of damage to RFID tags, can be applied to a variety of tires.

Reference Signs List 2: tire 4: tread 6: sidewall 8: chafer 10: bead 12: carcass 18: steel reinforcing layer 26: tag member 36: core 38: apex 38g: outer surface 38g of apex 38
Reference Signs List 40: Inner apex 42: Outer apex 44: Edge strip 46: Carcass ply 48: Ply body 50: Turn-up portion 52: Inner portion 54: Outer portion 60: Tag 62: Protector 64: Semiconductor chip 66: Antenna

Claims (5)

A tubeless type heavy-duty tire assembled on a rim, the rim being a 5-degree tapered rim,
A pair of beads;
a carcass extending between the pair of beads;
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 including a number of parallel steel cords,
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,
an end of the folded portion is located radially inside an outer end of the apex,
The tag member is laminated to an outer surface of the apex;
the RFID tag is located between an end of the folded portion and an outer end of the apex in a radial direction;
The ratio of the radial height of the folded portion to the flange height of the rim is 1.2 or more and 2.5 or less.
Heavy duty tires. the apex having an edge strip forming a part of its outer surface;
an outer end of the edge strip is located radially inside an outer end of the apex;
The end of the folded portion is laminated to the edge strip;
the RFID tag is positioned away from the outer end of the edge strip;
2. A heavy duty tire according to claim 1. A ratio of a radial height of the apex to a radial height of the folded-back portion is 1.50 or more and 2.50 or less.
3. A heavy duty tire according to claim 1 or 2. a pair of chafers contacting the rim;
The outer end of the tag member is located radially outward of the outer end of the chafer.
3. A heavy duty tire according to claim 1 or 2. A pair of steel reinforcing layers are folded back at the bead and include a number of parallel steel cords;
the steel reinforcing layer has an inner portion including an inner end of the steel reinforcing layer and positioned axially inward of the ply body, and an outer portion including an outer end of the steel reinforcing layer and positioned axially outward of the turned-up portion,
The ratio of the radial height of the outer portion to the radial height of the folded portion is 0.50 or more and 0.95 or less.
3. A heavy duty tire according to claim 1 or 2.

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