Bias tire

Abstract

To provide a bias tire 2 that can suppress lowering of durability caused by incorporating an electronic component 46.SOLUTION: A tire 2 includes a carcass 12, a tread 6, a pair of side walls 8, and a tag member 14 including an electronic component 46. The tread 6 includes a plurality of lugs 18. The carcass 12 includes at least two carcass plies 42. The at least two carcass plies 42 include at least one winding up ply 56, and at least one hanger ply 58. The tag member 14 is positioned between the carcass 12 and the side wall 8. The electronic component 46 is positioned on a radially outer side of a normal rim R with the tire 2 assembled on a normal rim R. The electronic component 46 is disposed apart from the ends of the winding up ply 56 and the hanger ply 58.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] Attaching electronic components such as RFID (Radio Frequency Identification) tags to tires has been proposed as a way to monitor various tire data and improve safety and maintainability while a vehicle is running. The electronic components are attached to the tire by, for example, attaching the electronic components to the surface of the tire or embedding the electronic components inside the tire. The method of attaching electronic components to the surface of a tire has the problem that the electronic components tend to fall off from the tire while the tire is running. In many cases, the method of embedding electronic components inside the tire is adopted (for example, Patent Document 1 below). When electronic components are built into tires, there is a concern that the durability of the tire may be reduced depending on where the electronic components are placed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-116027 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a bias tire that can suppress a decrease in durability due to the incorporation of electronic components. [Means for solving the problem]

[0005] The bias tire according to the present invention has a land ratio of 50% or less, as defined below, and includes a pair of beads, a carcass spanning the pair of beads, a tread positioned radially outward of the carcass, a pair of sidewalls positioned axially outward of the carcass, and a tag member including an electronic component. The tread includes a plurality of lugs. The outer surface of the tread includes a tread surface including the top surfaces of the plurality of lugs. The carcass includes at least two carcass plies. Each carcass ply includes a number of carcass cords arranged in parallel. In each carcass ply, each carcass cord is inclined with respect to the equatorial plane. The at least two carcass plies include at least one turnup ply that is turned up at each of the beads and at least one hanger ply that is not turned up at each of the beads. The turnup ply includes a ply body and a pair of turnup portions. The ply body spans the pair of beads. Each of the pair of turnup portions is connected to the ply body and turned up at the bead. The tag member is positioned between the carcass and the sidewall. When the tire is mounted on a standard rim, the electronic component is positioned radially outward from the standard rim. The electronic component is positioned away from each end of the turnup ply and the hanger ply. Land ratio: The ratio of the total area of ​​the top surfaces of the lugs included in the tread surface to the area of ​​the tread surface. [Effects of the Invention]

[0006] According to the present invention, a bias tire can be obtained that can suppress a decrease in durability due to the incorporation of electronic components. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a development view showing a portion of a tread surface of a bias tire according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is a schematic diagram illustrating the configuration of a carcass. [Figure 4] FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] 3 is a cross-sectional view showing a portion of the tire shown in FIG. 2. [Figure 7] FIG. 10 is a cross-sectional view illustrating a modified example of the carcass. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, the present invention will be described in detail based on preferred embodiments, with appropriate reference to the drawings.

[0009] The tire of the present invention is mounted on a rim. The inside of the tire is filled with air, 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.

[0010] 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 a standard internal pressure, and no load is applied to the tire is referred to as the standard state.

[0011] 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 of the tire's meridian cross section, which cannot be measured when the tire is mounted on a regular rim, are measured on a cut surface of the tire 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 matches the distance between the beads of the tire mounted on a regular rim. Note that the tire configuration, which cannot be confirmed when the tire is mounted on a regular rim, is confirmed on the cut surface.

[0012] A genuine rim is a rim 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 all genuine rims.

[0013] Normal tire pressure refers to the pressure specified in the standard on which the tire is based. The "maximum tire pressure" in the JATMA standard, the "maximum tire pressure" listed in the TRA standard's "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURE" and the "INFLATION PRESSURE" in the ETRTO standard are normal tire pressures.

[0014] 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 the "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the TRA standard, and the "LOAD CAPACITY" in the ETRTO standard are normal loads.

[0015] 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.

[0016] [Findings that form the basis of the present invention] For example, bias tires are often used for agricultural machinery. Agricultural machinery runs on fields with different road surface conditions, such as soft roads like rice paddies and dry soil fields. The tread patterns of agricultural machinery tires are significantly different from those of tires that run on paved roads.

[0017] Agricultural machinery tires have lugs in the tread area to provide traction and pulling power according to the field environment. These tires have a small land ratio and the lugs are quite high. While typical bias tires (hereinafter referred to as "general tires") without lugs tend to have higher rigidity in the sidewall area than in the tread area, this tire's sidewall rigidity tends to be lower than that of the tread area.

[0018] Tires absorb road irregularities by flexing. In the case of tires with lugs, as mentioned above, the tire absorbs road irregularities by flexing mainly in the sidewall, which has lower rigidity than the tread. Placing electronic components such as RFID tags in the sidewall, as in regular tires, could impair the durability of the tire.

[0019] Therefore, in order to obtain a bias tire that can suppress the decrease in durability caused by incorporating electronic components, the inventors took into consideration the rigidity of the tire and studied the location of incorporating the electronic components, and have completed the invention described below.

[0020] [Outline of the embodiment of the present invention] The present invention provides a tire having a land ratio of 50% or less, as defined below, the tire comprising: a pair of beads; a carcass spanning the pair of beads; a tread positioned radially outward of the carcass; a pair of sidewalls positioned axially outward of the carcass; and a tag member including an electronic component; the tread having a plurality of lugs; an outer surface of the tread having a tread surface including top surfaces of a plurality of the lugs; the carcass including at least two carcass plies; each carcass ply including a large number of carcass cords arranged in parallel; each carcass ply having an inclination with respect to an equatorial plane; a bias tire including at least one turn-up ply that is folded back at each of the beads and at least one hanger ply that is not folded back at each of the beads, the turn-up ply having a ply body and a pair of turn-up portions, the ply body spanning between the pair of beads, the pair of turn-up portions each continuing to the ply body and folded back at the beads, the tag member being positioned between the carcass and the sidewall, and when the tire is mounted on a regular rim, the electronic component being positioned radially outward of the regular rim and the electronic component being positioned away from each end of the turn-up ply and the hanger ply. Land ratio: The ratio of the total area of ​​the top surfaces of the lugs included in the tread surface to the area of ​​the tread surface.

[0021] The bias tire of the present invention can suppress the decrease in durability caused by the incorporation of electronic components. The mechanism by which this effect is achieved has not been clarified, but is presumed to be as follows.

[0022] The bias tire of the present invention has a tread provided with multiple lugs. The rigidity of the sidewall portion of this bias tire is lower than the rigidity of the tread portion, unlike that of a typical bias tire without lugs. This bias tire absorbs road surface irregularities by flexing the sidewall portion. This bias tire bends significantly, particularly between the portion that contacts the rim flange and the portion that does not. Large strain occurs near the boundary between the portion that contacts the rim flange and the portion that does not. However, when this bias tire is mounted on a standard rim, the electronic components are located radially outward from the standard rim. The electronic components are positioned away from areas of the bias tire where large strain occurs. Furthermore, the electronic components are also positioned away from the ends of the wraparound ply and hanger ply, where strain tends to concentrate. This bias tire can suppress the decrease in durability caused by incorporating electronic components.

[0023] Preferably, of the at least two carcass plies, the carcass cord included in the carcass ply closest to the electronic component is a cord made of organic fiber. In this case, the influence of the carcass ply close to the electronic component on the communication environment is suppressed. The electronic component of this bias tire can fully perform its functions.

[0024] Preferably, the electronic component is located radially outward of the position where the tire has its maximum width, which effectively prevents a decrease in durability due to the inclusion of the electronic component.

[0025] Preferably, a reference position is a position where a normal to the ply body of the wraparound ply, which passes through the edge of the tread surface, intersects with the ply body, the end of the hanger ply is located axially outward from the reference position, and the electronic component is located radially inward from the end of the hanger ply. In this case, a decrease in durability due to the incorporation of the electronic component is effectively suppressed.

[0026] Preferably, a reference position is a position where a normal to the ply body of the wraparound ply, which passes through the edge of the tread surface, intersects with the ply body, the end of the hanger ply is located axially inward of the reference position, and the electronic component is located radially inward of the reference position. In this case, a decrease in durability due to the incorporation of the electronic component is effectively suppressed.

[0027] Preferably, the present invention is directed to a tire for agricultural machinery. The bias tire of the present invention can suppress a decrease in durability due to the incorporation of electronic components, and can be suitably used as a bias tire for agricultural machinery.

[0028] [Details of the embodiment of the present invention] 1 and 2 show a portion of a bias tire 2 (hereinafter also simply referred to as "tire 2") according to one embodiment of the present invention. This tire 2 is mounted on agricultural machinery such as agricultural tractors, agricultural management machines, off-road vehicles, and agricultural implements. This tire 2 is suitable for traveling on fields such as wet paddy fields and farmlands.

[0029] Fig. 1 is a plan view (i.e., a developed view) of a tread surface 4 of a tire 2. Fig. 1 shows the tread pattern of the tire 2. In Fig. 1, a dashed line EL extending in the radial direction represents the equatorial plane of the tire 2. The position indicated by the symbol TE is the edge of the tread surface 4.

[0030] The direction indicated by the double arrow AD is the axial direction of the tire 2. The axial direction of the tire 2 means the direction parallel to the rotation axis of the tire 2. The direction from the equatorial plane toward the end TE of the tread surface 4 in the axial direction is the axially outer side. The direction from the end TE of the tread surface 4 toward the equatorial plane in the axial direction is the axially inner side. The direction indicated by the double arrow CD is the circumferential direction of the tire 2. The direction indicated by the arrow CD1 is the leading side of the tire 2, and the direction indicated by the arrow CD2 is the trailing side. As the tire 2 travels through the field, it makes contact with the road surface from the leading side toward the trailing side.

[0031] Fig. 2 shows a part of a cross section of the tire 2 taken along line II-II in Fig. 1. This cross section is a cross section of the tire 2 taken along a plane including the rotation axis of the tire 2 (hereinafter referred to as a meridian cross section). Line II-II in Fig. 1 is included in the meridian cross section of the tire 2. The direction indicated by the double-headed arrow RD is the radial direction of the tire 2. The direction indicated by the arrow RD1 is the radially inner side of the tire 2, and the direction indicated by the arrow RD2 is the radially outer side of the tire 2. The position indicated by the symbol Eq is the equator of the tire 2. The equator Eq is the intersection of the equatorial plane and the tread surface 4, and is the outer end of the tire 2 in the radial direction.

[0032] In Fig. 2, the tire 2 is mounted on a rim R. The rim R is a regular rim. The inside of the tire 2 is filled with, for example, air, and the internal pressure is adjusted. Although not shown, a tube is inserted into the tire 2 and filled with air. The tire 2 is a tube type. The tire 2 may also be a tubeless type.

[0033] The rim R has a seat RS and a pair of flanges RF. Each flange RF extends radially outward from the seat RS. The bead portion of the tire 2 is placed on the seat RS. The bead portion is pressed against the flange RF from the inside to the outside in the axial direction. The position indicated by the symbol PR in FIG. 1 is the radial outer end of the flange RF, in other words, the radial outer end of the rim R.

[0034] The tire 2 includes a tread 6, a pair of sidewalls 8, a pair of beads 10, a carcass 12, and a tag member 14.

[0035] The tread 6 is made of cross-linked rubber. The tread 6 comes into contact with the road surface. The tread 6 is located radially outward of the carcass 12. The outer surface of the tread 6 includes the tread surface 4 described above. The tread 6 is the main element of the tread portion. Although not described in detail, the tread 6 is made of a cross-linked rubber that is generally used as a cross-linked rubber for the tread of a bias tire.

[0036] The tread 6 of the tire 2 includes a base portion 16 and a plurality of lugs 18 . The lugs 18 protrude from the base portion 16. Top surfaces 20 of the lugs 18 are included in the tread surface 4. The tread surface 4 includes the top surfaces 20 of the plurality of lugs 18 provided in the tread 6. The outer surface 22 of the base portion 16 is represented by a virtual outer surface of the tread 6 that would be obtained if the tread 6 did not have the lugs 18. The outer surface 22 of the base portion 16 is also referred to as the reference plane TBL of the tread 4. The lugs 18 protrude outward from the reference plane TBL. The space between two adjacent lugs 18 is called a lug bottom 24. The lug bottom 24 is included in the outer surface 22 of the base portion 16 (in other words, the reference plane TBL).

[0037] Between the top surface 20 and the lug bottom 24 of the lug 18 is the slope 26 of the lug 18. The slope 26 and the lug bottom 24 of the lug 18 form a depression in the tread surface 4. The portion of the tread surface 4 other than the top surface 20 of the lug 18 is the depression. The depression corresponds to the groove in a tire without lugs, and the top surface 20 of the lug 18 corresponds to the portion of the tire without lugs other than the groove, i.e., the land surface.

[0038] The land ratio is the ratio of the total area of ​​the top surfaces 20 of the lugs 18 included in the tread surface 4 to the area of ​​the tread surface 4. This land ratio is specified in a developed view of the tread surface 4. The land ratio of this tire 2 is smaller than that of a tire without lugs, such as a passenger tire.

[0039] The lugs 18 include ends TE of the tread surface 4. The lugs 18 have side surfaces 28 extending radially inward from the ends TE of the tread surface 4. The ends TE of the tread surface 4 are the boundaries between the top surfaces 20 of the lugs 18 and the side surfaces 28 thereof. When the corner formed by the top surface 20 and the side surface 28 is rounded, as in the lug 18 of this tire 2, the edge TE of the tread surface 4 is represented by the intersection of the extension line LT of the top surface 20 and the extension line LS of the side surface 28.

[0040] Of the ends TE of the left and right tread surfaces 4, the end TE indicated by the symbol TE1 is also called the first end, and the end TE indicated by the symbol TE2 is also called the second end. In the tread surface 4 shown in FIG. 1, one end TE located in the direction indicated by the arrow AD1 is the first end TE1. The other end TE located in the direction indicated by the arrow AD2 is the second end TE2. The end TE located in the direction indicated by the arrow AD1 may also be called the second end TE2, and the end TE located in the direction indicated by the arrow AD2 may also be called the first end TE2.

[0041] As described above, the tread 6 of the tire 2 has a plurality of lugs 18. Each of the plurality of lugs 18 has a tip end 30 located on the equatorial plane and a rear end 32 located on the end TE side of the tread surface 4. The above-mentioned side surface 28 is included in the rear end 32 of the lug 18. The lugs 18 extend from the leading end portions 30 toward the trailing end portions 32. In the circumferential direction, the leading end portions 30 are located ahead of the trailing end portions 32. When the tire 2 is in a running state, the lugs 18 come into contact with the road surface from the leading end portions 30 toward the trailing end portions 32.

[0042] The multiple lugs 18 of this tire 2 include multiple first lugs 34 located in a zone between the equatorial plane and a first end TE1 of the tread surface 4 (hereinafter also referred to as the first zone), and multiple second lugs 36 located in a zone between the equatorial plane and a second end TE2 of the tread surface 4 (hereinafter also referred to as the second zone).

[0043] The first lugs 34 are arranged in the first zone at predetermined intervals in the circumferential direction. The first lugs 34 extend from the equatorial plane toward a first end TE1 of the tread surface 4. The second lugs 36 are arranged in the second zone at predetermined intervals in the circumferential direction. The second lugs 36 extend from the equatorial plane toward the second end TE2 of the tread surface 4. 1, the first lugs 34 and the second lugs 36 are arranged alternately in the circumferential direction. The first lugs 34 and the second lugs 36 alternately come into contact with the road surface.

[0044] In the meridian cross section of this tire 2, the contour line of the tread surface 4 is represented by the contour line of the top surface 20 of the first lug 34 and the contour line of the top surface of the second lug 36.

[0045] Each sidewall 8 is continuous with an edge of the tread 6. The sidewalls 8 are located radially inward of the tread 6. The sidewalls 8 are located axially outward of the carcass 12. The pair of sidewalls 8 are arranged on either side of the equatorial plane. In Fig. 1, the sidewall 8a located on the first end TE1 side of the tread surface 4 is also called the first sidewall. The sidewall 8b located on the second end TE2 side of the tread surface 4 is also called the second sidewall.

[0046] The sidewall 8 is made of cross-linked rubber. The sidewall 8 is softer than the tread 4. The sidewall 8 is a main element of the sidewall portion. Although not described in detail, the sidewall 8 is made of a cross-linked rubber that is generally used as a cross-linked rubber for the sidewall of a bias tire. 2, the outer ends of the sidewalls 8 are located radially outward of the ends of the tread 6. The outer ends of the sidewalls 8 are covered by the tread 6, specifically, by the base portion 16.

[0047] 2, the position indicated by the symbol PW is the axially outer end of the tire 2. The tire 2 has a maximum width at the axially outer end PW. The axially outer end PW is also called a maximum width position. The maximum width position PW is determined based on a virtual outer surface of the tire 2 obtained assuming that there are no lugs 18, decorations such as patterns or letters, or irregularities such as protrusions or depressions. Although not described in detail, the virtual outer surface is expressed using a plurality of arcs and straight lines in a meridian cross section of the tire 2. This virtual outer surface of the tire 2 includes the reference surface TBL of the tread 6 described above. In FIG. 2, the two-dot chain line VL represents the virtual outer surface of the tire 2. In the present invention, the axial distance from the first axially outer end PW to the second axially outer end PW obtained in the tire 2 in a normal state is the section width of the tire 2 (see JATMA, etc.).

[0048] Each bead 10 is located radially inward of the sidewall 8. The bead 10 is the main element of the bead portion. The bead 10 includes a core 38 and an apex 40. The core 38 extends in the circumferential direction. Although not shown, the core 38 includes a steel wire. The apex 40 is located radially outward of the core 38. The apex 40 includes a radially outer end PA of the bead 10. In this tire 2, the radially outer end PA of the bead 10 is located radially outward of the radially outer end PR of the rim R. The apex 40 tapers toward the radially outer end PA. The apex 40 is made of crosslinked rubber with high rigidity.

[0049] The carcass 12 is located inside the tread 6 and the pair of sidewalls 8. The carcass 12 bridges between the pair of beads 10. The carcass 12 forms the skeleton of the tire 2.

[0050] The carcass 12 includes at least two carcass plies 42. The carcass 12 of the tire 2 is composed of three carcass plies 42.

[0051] 3 shows the configuration of the carcass 12. The configuration of the carcass 12 shown in FIG.

[0052] 3, each carcass ply 42 includes a large number of parallel carcass cords 44. For ease of explanation, the carcass cords 44 are represented by solid lines, but in the carcass ply 42, the carcass cords 44 are covered with a topping rubber 45. In each carcass ply 42, the carcass cords 44 do not intersect perpendicularly to the equatorial plane but intersect obliquely with respect to the equatorial plane. The carcass cords 44 are inclined with respect to the equatorial plane. The carcass 12 has a bias structure. The carcass 12 is a bias structure carcass.

[0053] 3, between two carcass plies 42 adjacent to each other in the radial direction, the inclination direction of the carcass cords 44 included in one carcass ply 42 is opposite to the inclination direction of the carcass cords 44 included in the other carcass ply 42. The carcass cords 44 included in one carcass ply 42 intersect with the carcass cords 44 included in the other carcass ply 42.

[0054] The tag member 14 is located between the carcass 12 and the sidewall 8. The tag member 14 is laminated on the outer surface of the carcass 12 and is covered from the outside by the sidewall 8. As shown in FIG. 2 , the tag member 14 is covered by the sidewall 8 located between the tread 4 and the carcass 12. The tag member 14 is sandwiched between the carcass 12 and the sidewall 8.

[0055] In this tire 2, one tag member 14 is provided only on the first sidewall 8a side. The tag member 14 may be provided on both the first sidewall 8a side and the second sidewall 8b side. From the viewpoint of suppressing a decrease in durability, it is preferable that the tag member 14 be provided on the side of either the first sidewall 8a or the second sidewall 8b, that is, on only one of the pair of sidewalls 8. Although multiple tag members 14 may be provided at intervals in the circumferential direction, from the viewpoint of suppressing a decrease in durability, it is sufficient that one tag member 14 is provided on one of the sidewalls 8 side.

[0056] Fig. 4 is a plan view of the tag member 14. Fig. 5 is a cross-sectional view taken along line VV in Fig. 4. The tag member 14 has a plate shape. The tag member 14 is long in the length direction and short in the width direction. As shown in Fig. 2, the tag member 14 is arranged in the tire 2 so that a first end 14s in the width direction thereof is located on the radially outer side of the tire 2 and a second end 14u is located on the inner side. In this tire 2, the first end 14s is also called the outer end, and the second end 14u is also called the inner end.

[0057] The tag member 14 includes an electronic component 46. In FIG. 4, the electronic component 46 is shown with a solid line for ease of explanation, and is entirely covered with a protective body 48. The tag member 14 includes the electronic component 46 and the protective body 48. The electronic component 46 is located at the center of the tag member 14. The protective body 48 is made of cross-linked rubber. The protective body 48 has a rigidity similar to that of the sidewall 8. In this tire 2, the formation of a good communication environment is taken into consideration, and a cross-linked rubber with high electrical resistance is used for the protective body 48. The protective body 48 is made of rubber with high insulating properties.

[0058] The electronic component 46 is a small and lightweight electronic component. Although not described in detail, the electronic component 46 of the tire 2 is an RFID tag 54 that is composed of a semiconductor chip 50 that integrates a transmitting / receiving circuit, a control circuit, a memory, etc., and an antenna 52. When the RFID tag 54 receives an interrogation radio wave, it uses the received interrogation radio wave as electrical energy and transmits the data stored in the memory as a response radio wave. The RFID tag 54 is a type of passive radio frequency identification transponder.

[0059] The tag member 14 is a plate-shaped member in which an electronic component 46 is covered with cross-linked rubber. From the viewpoints of reducing the risk of damage to the electronic component 46 and creating a good communication environment, the thickness of the tag member 14 in the meridian cross section of the tire 2 is preferably 1.0 mm or more and 2.5 mm or less. The thickness of the tag member 14 in the tire 2 is represented by the maximum thickness of the tag member 14 in the semiconductor chip 50 constituting the RFID tag 54. The length TL of the tag member 14 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.

[0060] Fig. 6 shows a part of the meridian cross section shown in Fig. 1. Fig. 6 shows a portion of the meridian cross section of the tire 2 shown in Fig. 2 on the right side of the equatorial plane, that is, the meridian cross section on the first end TE1 side of the tread surface 4. In this meridian cross section of the tire 2, the carcass 12 has a structure symmetrical with respect to the equatorial plane.

[0061] 6, the position indicated by the symbol TU is the radially inner end of the electronic component 46 (specifically, the semiconductor chip 50). The position indicated by the symbol TS is the radially outer end of the electronic component 46. In the case of this tire 2, the radially inner end TU of the electronic component 46 is represented by the radially inner end of the semiconductor chip 50 of the RFID tag 54. The radially outer end TS of the electronic component 46 is represented by the radially outer end of the semiconductor chip 50 of the RFID tag 54. In the present invention, when the inner end TU of the electronic component 46 in the tire 2 is located radially outward from a reference position (hereinafter referred to as the reference position), the electronic component 46 is located radially outward from the reference position. When the outer end TS of the electronic component 46 is located radially inward from the reference position, the electronic component 46 is located radially inward from the reference position.

[0062] As described above, the carcass 12 includes at least two carcass plies 42. The carcass 12 of the tire 2 includes two different types of carcass plies 42. The first type of carcass ply 42 is a type of carcass ply 42 that is turned up at each bead 10. The carcass ply 42 that is turned up at each bead 10 is also called a turn-up ply. The second type of carcass ply 42 is a type of carcass ply 42 that is not turned up at each bead 10. The carcass ply 42 that is not turned up at each bead 10 is also called a hanger ply. The carcass 12 of the tire 2 includes at least two carcass plies 42. The at least two carcass plies 42 include at least one turnup ply that is turned up at each bead 10 and at least one hanger ply that is not turned up at each bead 10.

[0063] In the present invention, the turnup ply refers to the carcass ply 42 folded back at each bead 10 so that the end of the carcass ply 42 is located radially outside the core 38 of the bead 10. If the end of the carcass ply 42 is not located radially outside the core 38 as a result of folding back the carcass ply 42 at the bead 10, then the carcass ply 42 is not a turnup ply but a hanger ply.

[0064] As described above, the carcass 12 of the tire 2 is composed of three carcass plies 42. Of the three carcass plies 42, the two carcass plies 42 located on the inner side are turned up at each bead 10. The two carcass plies 42 located on the inner side are turn-up plies 56.

[0065] Each of the two turnup plies 56 is folded back at each bead 10. Each turnup ply 56 includes a ply body 56m and a pair of turnup portions 56t. The ply body 56m spans between the pair of beads 10. Each of the pair of turnup portions 56t is connected to the ply body 56m and turned back at the bead 10. The turnup portions 56t of this tire 2 are turned back at the bead 10 from the inside toward the outside in the axial direction.

[0066] The turned-up portions 56t of each turn-up ply 56 are aligned in the axial direction on the axially outer side of the bead 10. Since the carcass 12 of this tire 2 includes two turn-up plies 56, the two turned-up portions 56t are aligned in the axial direction. In the tire 2, the turned-up portion 56t located outermost in the axial direction is a first turned-up portion 56t1. The turned-up portion 56t located axially inside the first turned-up portion 56t1 is a second turned-up portion 56t2.

[0067] The roll-up ply 56 including the first turned-up portions 56t1 is also referred to as a first roll-up ply 56a, and the ply body 56m of the first roll-up ply 56a is also referred to as a first ply body 56m1. The first roll-up ply 56a includes a first ply body 56m1 and a pair of first turned-up portions 56t1.

[0068] The roll-up ply 56 including the second turned-up portions 56t2 is also referred to as a second roll-up ply 56b, and the ply body 56m of the second roll-up ply 56b is also referred to as a second ply body 56m2. The second roll-up ply 56b includes a second ply body 56m2 and a pair of second turned-up portions 56t2.

[0069] In the tire 2, of the two ply bodies 56m included in the carcass 12, the first ply body 56m1 is the innermost ply body 56m, and the second ply body 56m2 is the outermost ply body 56m. The second turnup ply 56b, which includes the outermost second ply body 56m2, is the outermost turnup ply 56 of the turnup plies 56 included in the carcass 12 and is also referred to as the outer turnup ply 56s. The first turnup ply 56a, which includes the innermost first ply body 56m1, is also referred to as the inner turnup ply 56u. When the carcass 12 includes three or more turnup plies 56, the turnup ply 56 located between the inner turnup ply 56u and the outer turnup ply 56s is also referred to as the intermediate turnup ply.

[0070] In the tire 2, the portion of the carcass 12 that is configured with the turnup ply 56 is also referred to as the carcass body 60. As described above, of the three carcass plies 42, the two carcass plies 42 located on the inner side are the turnup plies 56. The carcass body 60 of the tire 2 includes two turnup plies 56. The carcass body 60 needs to be configured with at least one turnup ply 56, and the carcass body 60 may be configured with three or more turnup plies 56. In other words, the carcass 12 of the tire 2 includes the carcass body 60, and the carcass body 60 includes at least one carcass ply 42. At least one carcass ply 42 included in the carcass body 60 is the turnup ply 56 that is turned up at each bead 10.

[0071] As shown in FIG. 6, an end 56t1e of the first folded portion 56t1 and an end 56t2e of the second folded portion 56t2 are located between the maximum width position PW and the radially outer end PR of the rim R in the radial direction. In order to prevent strain from concentrating on the end 56te of the folded portion 56t, it is preferable that the end 56t1e of the first folded portion 56t1 and the end 56t2e of the second folded portion 56t2 be spaced apart from each other. Specifically, it is preferable that the radial distance from the end 56t1e of the first folded portion 56t1 to the end 56t2e of the second folded portion 56t2 be 10 mm or more and 50 mm or less.

[0072] An end 56t1e of the first turned-up portion 56t1 is located radially outward of an end 56t2e of the second turned-up portion 56t2. The end 56t1e of the first turned-up portion 56t1 is the end 56te of the turned-up portion 56t included in the carcass ply 42 that is located radially outermost. In the tire 2, the end 56t2e of the second turned-up portion 56t2 may be disposed radially outward of the end 56t1e of the first turned-up portion 56t1. In this case, the end 56t2e of the second turned-up portion 56t2 is the end 56te of the turned-up portion 56t that is positioned radially outermost. In order to suppress the concentration of strain at the end 56te of the folded portion 56t, which is located at the outermost radial position, it is preferable that the radial distance from the end 56te of the folded portion 56t, which is located at the outermost radial position, to the maximum width position PW be 10 mm or more and 30 mm or less.

[0073] The first folded portion 56t1 is located axially outward of the second folded portion 56t2. The first folded portion 56t1 covers the end 56t2e of the second folded portion 56t2. This suppresses strain concentration at the end 56t2e of the second folded portion 56t2. From this perspective, it is preferable that the end 56t1e of the first folded portion 56t1 be located radially outward of the end 56t2e of the second folded portion 56t2. In other words, it is preferable that, of the multiple folded portions 56t aligned in the axial direction, the end 56te of the outer folded portion 56t be located radially outward of the end 56te of the inner folded portion 56t.

[0074] In this tire 2, of the three carcass plies 42 constituting the carcass 12, one carcass ply 42 located on the outermost side is not turned up at each bead 10. This carcass ply 42 is a hanger ply 58. The carcass 12 of this tire 2 includes one hanger ply 58. The hanger ply 58 is located on the outer side of the two wrap-up plies 56 included in the carcass 12.

[0075] The hanger ply 58 is not folded back at the beads 10. The hanger ply 58 extends from the equatorial plane toward each of the beads 10. An end 58e of the hanger ply 58 of this tire 2 is located radially outward of the maximum width position PW.

[0076] As described above, the carcass 12 of the tire 2 includes one hanger ply 58. It is sufficient that the carcass 12 includes at least one hanger ply 58, and the carcass 10 may include two or more hanger plies 58. For example, when the carcass 12 includes two hanger plies 58, the hanger ply 58 located on the innermost side is the first hanger ply, and the hanger ply 58 located on the outer side of the first hanger ply is the second hanger ply.

[0077] As described above, the carcass 12 of the tire 2 includes a carcass body 60 configured from two wrap-up plies 56. The hanger ply 58 of the tire 2 is layered on the outside of the carcass body 60, as shown in FIG. 6 . In the present invention, a member made up of the hanger ply 58 layered on the outside of the carcass body 60 is also referred to as a carcass jacket 62. The carcass jacket 62 needs to be configured with at least one hanger ply 58, and the carcass jacket 62 may be configured with two or more hanger plies 58. In other words, the carcass 12 of the tire 2 includes a carcass jacket 62 layered on the outside of the carcass body 60, and the carcass jacket 62 includes at least one carcass ply 42. The at least one carcass ply 42 included in the carcass jacket 62 is a hanger ply 58 that is not folded up at each bead 10.

[0078] 6, the solid line NL is a normal to the second ply body 56m2 of the second winding ply 56b, which is the outer winding ply 56s, passing through the edge TE of the tread surface 4. The position indicated by the symbol PB is the intersection position of the normal line NL and the second ply body 56m2. This intersection position PB is also called the reference position.

[0079] In the present invention, the reference position is the position where a normal to the ply body of the winding ply that passes through the edge of the tread surface intersects with the ply body. When the carcass includes multiple winding plies, the reference position is determined by the normal to the ply body of the outermost winding ply, i.e., the outer winding ply.

[0080] 6, the end 58e of the hanger ply 58 of the tire 2 is located axially outward from the reference position PB. The end 58e of the hanger ply 58 is located radially inward from the reference position PB.

[0081] In Fig. 3, the angle indicated by the symbol α1 is the angle that the carcass cord 44 included in the first winding ply 56a makes with respect to the equatorial plane (hereinafter referred to as the inclination angle of the first carcass cord 44a). The angle indicated by the symbol α2 is the angle that the carcass cord 44 included in the second winding ply 56b makes with respect to the equatorial plane (hereinafter referred to as the inclination angle of the second carcass cord 44b). The angle indicated by the symbol β is the angle that the carcass cord 44 included in the hanger ply 58 makes with respect to the equator plane (hereinafter referred to as the inclination angle of the third carcass cord 44c).

[0082] As described above, the carcass 12 of the tire 2 has a bias structure. The inclination angle α1 of the first carcass cords 44a of the first winding ply 56a is preferably 25 degrees or greater and 45 degrees or less. The inclination angle α2 of the second carcass cords 44b of the second winding ply 56b is preferably 25 degrees or greater and 45 degrees or less. The inclination angle β of the third carcass cord 44c of the hanger ply 58 is preferably equal to or greater than 25 degrees and equal to or less than 45 degrees.

[0083] The tire 2 is a bias tire. The tread 6 of the tire 2 has a plurality of lugs 18. Therefore, as described above, the land ratio of the tire 2 is smaller than the land ratio of a tire without lugs. Specifically, the land ratio of the tire 2 is 50% or less.

[0084] The lugs 18 have a considerable height in order to plow through the field. The height of the lugs 18 measured along the normal to the outer wrap ply 56s is maximum at the normal NL passing through the edge TE of the tread surface 4. Specifically, the height of the lugs 18 measured along this normal NL is Between 5mm and 100mm. The lugs 18 have a considerable axial width for plowing through the field. Specifically, the axial width of the lugs 18 is 50 mm or more and 230 mm or less. 1 is the width of the top surface 20 of the lug 18, in other words, the thickness of the lug 18 at the top surface 20. The width w of the top surface 20 is represented by the average of the maximum and minimum values ​​measured along a line perpendicular to the center line of the width of the top surface 20. The lugs 18 also have a substantial thickness for plowing through the field. Specifically, the thickness of the lugs 18 at the top surface 20 is 10 mm or more and 40 mm or less. The lugs 18 increase the rigidity of the tread portion. Therefore, in this tire 2, unlike a general bias tire without lugs, the rigidity of the sidewall portion tends to be lower than the rigidity of the tread portion.

[0085] Tires absorb unevenness in the road surface by flexing. This tire 2 absorbs unevenness in the road surface by mainly flexing the sidewall portion, which has lower rigidity than the tread portion. This tire 2 bends significantly, especially between the portion that contacts the flange RF of the rim R and the portion that does not. As a result, large distortion tends to occur near the boundary between the portion that contacts the flange RF of the rim R and the portion that does not. In a typical bias tire without lugs, electronic components are placed in the sidewall portion, which has a relatively high rigidity. However, if electronic components 46 are placed in the sidewall portion of tire 2 in the same way as in a typical bias tire, the durability of tire 2 may be impaired.

[0086] As described above, the carcass 12 of the tire 2 includes at least two carcass plies 42. The at least two carcass plies 42 include at least one turnup ply 56 that is turned up at each bead 10 and at least one hanger ply 58 that is not turned up at each bead 10. The sidewall portion of the tire 2 has an end 56te of the winding ply 56 and an end 58e of the hanger ply 58. Since strain tends to concentrate at the end 56te of the winding ply 56 and the end 58e of the hanger ply 58, for example, if the electronic component 46 is disposed near the end 56te of the winding ply 56, the durability of the tire 2 may be impaired.

[0087] However, in this tire 2, when the tire 2 is mounted on the rim R, the electronic component 46 is located radially outside the rim R, more specifically, radially outside the radially outer end PR of the rim R. The electronic component 46 of this tire 2 is disposed away from a portion where large strain occurs due to bending of the sidewall portion. Moreover, as shown in Fig. 6 , the electronic component 46 is also disposed away from an end 56te of the wrap-up ply 56 and an end 58e of the hanger ply 58, where strain is likely to concentrate. The tire 2 can suppress a decrease in durability due to the incorporation of the electronic component 46.

[0088] As described above, the carcass ply 42 includes the carcass cords 44. The carcass 12 of the tire 2 includes, as the carcass ply 42, the turnup ply 56 and the hanger ply 58. The turnup ply 56 and the hanger ply 58 each include the carcass cords 44. As described above, the tag member 14 is laminated on the carcass 12. As shown in Fig. 6, in the tire 2, the tag member 14 is laminated on the ply body 56m2 of the second winding ply 56b, which is the outer winding ply 56s. Of the three carcass plies 42 that constitute the carcass 12 of this tire 2, the carcass ply 42 that is closest to the electronic component 46 is the outer wraparound ply 56s.

[0089] In this tire 2, the carcass cords 44 included in the outer winding ply 56s are not steel cords but are cords made of organic fibers. In this tire 2, radio wave disturbances are suppressed, and a good communication environment is created. As described above, this tire 2 can suppress a decrease in durability due to the incorporation of the electronic components 46. Therefore, this tire 2 can suppress a decrease in durability due to the incorporation of the electronic components 46, and can maintain a good communication environment. From this perspective, in this tire 2, of the at least two carcass plies 42 included in the carcass 12, the carcass cords 44 included in the carcass ply 42 closest to the electronic components 46 are preferably cords made of organic fibers.

[0090] From the viewpoint of suppressing radio wave disturbance and creating a good communication environment, the carcass cords 44 included in the inner winding ply 56u are also preferably cords made of organic fibers. From the same viewpoint, the carcass cords 44 included in the hanger ply 58 are also preferably cords made of organic fibers.

[0091] From the viewpoint of suppressing radio wave disturbance and forming a good communication environment, it is more preferable that the carcass cords 44 of all the carcass plies 42 included in the carcass 12 are cords made of organic fibers.

[0092] When the carcass cords 44 are cords made of organic fibers, examples of the organic fibers include nylon fibers, rayon fibers, polyester fibers, and aramid fibers. In the tire 2, among the cords made of organic fibers, cords made of nylon fibers are preferably used as the carcass cords 44.

[0093] In this tire 2, the electronic component 46 is located radially outward from the maximum width position PW. This allows the electronic component 46 to be positioned closer to the tread 6. The electronic component 46 of this tire 2 is positioned away from a portion where large strain occurs due to bending of the sidewall portion. Moreover, the electronic component 46 is positioned away from the end 56te of the wraparound ply 56 and the end 58e of the hanger ply 58. This tire 2 can suppress a decrease in durability due to the incorporation of the electronic component 46. From this viewpoint, it is preferable that the electronic component 46 be positioned radially outward of the maximum width position PW.

[0094] The tread 6 of this tire 2 is thin at the lug bottoms 24. If stones or the like buried in the field come into contact with the lug bottoms 24, there is a concern that the lug bottoms 24 may be damaged. The zone from the normal line NL on the first end TE1 side of the tread surface 4 to the normal line NL on the second end TE2 side is a zone where such damage is likely to occur. As described above, the end 58e of the hanger ply 58 is located axially outward of the reference position PB. The hanger ply 58 contributes to reducing the risk of injury while traveling in a field. The tire 2 has good durability. As shown in FIG. 6 , the electronic component 46 is located radially inward of the end 58e of the hanger ply 58. In the tire 2, the electronic component 46 is located in a zone where external damage is unlikely to occur, and is located away from the end 58e of the hanger ply 58. In the tire 2, damage to the electronic component 46 and a decrease in durability due to the incorporation of the electronic component 46 can be suppressed. From this viewpoint, as shown in FIG. 6 , when the end 58e of the hanger ply 58 is located axially outward of the reference position PB, the electronic component 46 is preferably located radially inward of the end 58e of the hanger ply 58. In this case, it is more preferable that the electronic component 46 be located radially between the end 58e of the hanger ply 58 and the maximum width position PW.

[0095] Fig. 7 shows a modified example of the carcass 12. In the carcass 12 shown in Fig. 7, the end 58e of the hanger ply 58 is located axially inward of the reference position PB. When the end 58e of the hanger ply 58 is located axially inward of the reference position PB, the electronic component 46 is preferably located radially inward of the reference position PB. Even in this case, the electronic component 46 is disposed in a zone where external damage is unlikely to occur, and is disposed away from the end 58e of the hanger ply 58. The tire 2 can suppress damage to the electronic component 46 and a decrease in durability due to the incorporation of the electronic component 46.

[0096] As is clear from the above description, the present invention provides a bias tire that can suppress the decrease in durability caused by incorporating electronic components. The present invention is particularly effective for agricultural machinery tires that run on fields with different road surface conditions, such as soft roads like rice paddies and dry soil fields. [Industrial Applicability]

[0097] The above-described technology capable of suppressing a decrease in durability due to the incorporation of electronic components can be applied to various types of tires.

[0098] [Note] The present invention includes the following aspects.

[0099] [1] A tire having a land ratio of 50% or less, as defined below: a pair of beads, a carcass spanning the pair of beads, a tread positioned radially outward of the carcass, a pair of sidewalls positioned axially outward of the carcass, and a tag member including an electronic component; the tread comprises a plurality of lugs; an outer surface of the tread including a tread surface including top surfaces of a plurality of the lugs; The carcass includes at least two carcass plies, each of which includes a number of carcass cords arranged in parallel, and in each of the carcass plies, each carcass cord is inclined with respect to an equatorial plane; The at least two carcass plies include at least one turnup ply that is turned up at each of the beads and at least one hanger ply that is not turned up at each of the beads; The winding ply includes a ply body and a pair of turn-up portions, The ply body spans between the pair of beads, and the pair of turned-up portions are respectively connected to the ply body and turned up at the beads, the tag member is located between the carcass and the sidewall, When the tire is mounted on a regular rim, the electronic component is located radially outward of the regular rim, the electronic components are positioned away from the ends of the winding ply and the hanger ply, Bias tires. Land ratio: The ratio of the total area of ​​the top surfaces of the lugs included in the tread surface to the area of ​​the tread surface. [2] The bias tire according to the above-mentioned [1], wherein, of the at least two carcass plies, the carcass cord included in the carcass ply closest to the electronic component is a cord made of organic fiber. [3] The bias tire according to [1] or [2] above, wherein the electronic component is located radially outward of the position where the tire has its maximum width. [4] An intersection position between a normal to the ply body of the winding ply, which passes through the edge of the tread surface, and the ply body is a reference position; The end of the hanger ply is located axially outward from the reference position, The bias tire according to the above-mentioned [3], wherein the electronic component is located radially inside the end of the hanger ply. [5] An intersection position between a normal to the ply body of the winding ply, which passes through the edge of the tread surface, and the ply body is a reference position; The end of the hanger ply is located axially inside the reference position, The bias tire according to the above-mentioned [3], wherein the electronic component is located radially inside the reference position. [6] The bias tire according to any one of [1] to [5] above, which is a tire for agricultural machinery. [Explanation of symbols]

[0100] 2. Tires 4. Tread surface 6. Tread 8, 8a, 8b... Sidewall 10 Bead 12. Carcass 14. Tag member 16 Base 18···Rag 20...Top surface 24···Lug bottom 42···Carcass ply 44, 44a, 44b, 44c... Carcass cord 46 Electronic Components 48 Protective body 54... RFID tags 56, 56a, 56b, 56s, 56u···Winding ply 56m, 56m1, 56m2... Ply body 56t, 56t1, 56t2...Folded section 58···Hanger ply 60···Carcass body 62···Carcass Jacket

Claims

1. A tire having a land ratio of 50% or less as defined below, a pair of beads, a carcass spanning the pair of beads, a tread positioned radially outward of the carcass, a pair of sidewalls positioned axially outward of the carcass, and a tag member including an electronic component; the tread comprises a plurality of lugs; an outer surface of the tread including a tread surface including top surfaces of a plurality of the lugs; the carcass includes at least two carcass plies, each of the carcass plies includes a number of carcass cords arranged in parallel, and in each of the carcass plies, each carcass cord is inclined with respect to an equatorial plane; The at least two carcass plies include at least one turnup ply that is turned up at each of the beads and at least one hanger ply that is not turned up at each of the beads; The winding ply includes a ply body and a pair of turn-up portions, The ply body spans between the pair of beads, and the pair of turned-up portions are respectively connected to the ply body and turned up at the beads, the tag member is located between the carcass and the sidewall, When the tire is mounted on a regular rim, the electronic component is located radially outward of the regular rim, the electronic components are positioned away from the ends of the winding ply and the hanger ply, Bias tires. Land ratio: The ratio of the total area of ​​the top surfaces of the lugs included in the tread surface to the area of ​​the tread surface.

2. Among the at least two carcass plies, a carcass cord included in the carcass ply closest to the electronic component is a cord made of organic fiber.

2. The bias tire of claim 1.

3. The electronic component is located radially outward from a position where the tire has a maximum width.

2. The bias tire of claim 1.

4. An intersection position between a normal to the ply body of the winding ply, which passes through the edge of the tread surface, and the ply body is a reference position, The end of the hanger ply is located axially outward from the reference position, The electronic component is located radially inside the end of the hanger ply.

4. The bias tire according to claim 3.

5. An intersection position between a normal to the ply body of the winding ply, which passes through the edge of the tread surface, and the ply body is a reference position, The end of the hanger ply is located axially inside the reference position, The electronic component is located radially inside the reference position.

4. The bias tire according to claim 3.

6. It is a tire for agricultural machinery. A bias tire according to any one of claims 1 to 5.

Images