Bias tires
The bias tire design embeds electronic components within the tread between lugs, enhancing rigidity and reducing strain, thus maintaining durability and communication effectiveness for agricultural machinery.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- SUMITOMO RUBBER INDUSTRIES LTD
- Filing Date
- 2024-11-26
- Publication Date
- 2026-06-05
Smart Images
Figure 2026092423000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a bias tire.
Background Art
[0002] In order to monitor various data of a tire and improve safety and maintainability during vehicle travel, it has been proposed to attach an electronic component such as an RFID (Radio Frequency Identification) tag to the tire. The electronic component is attached to the tire by attaching the electronic component to the surface of the tire, embedding the electronic component inside the tire, etc. The method of attaching an electronic component to the surface of a tire has a problem that the electronic component is likely to fall off from the tire during running. In many cases, a method of embedding an electronic component inside the tire is adopted (for example, Patent Document 1 below). When an electronic component is built in a tire, there is a concern that the durability of the tire may decrease depending on the location where the electronic component is placed.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] An object of the present invention is to provide a bias tire capable of suppressing a decrease in durability due to incorporating an electronic component while ensuring a good communication environment.
Means for Solving the Problems
[0005] The bias tire according to the present invention comprises a pair of beads, a cord reinforcement body spanning between the pair of beads and including reinforcing cords, a tread located radially outward from the cord reinforcement body, a pair of sidewalls located axially outward from the cord reinforcement body, and a tag member including electronic components. The tread comprises a plurality of lugs separated by grooves and arranged circumferentially. The ratio of the lug height of each lug to the minimum thickness of the portion of the tire including the sidewalls is 3.3 or more. The cord reinforcement body comprises a carcass spanning between the pair of beads, or the cord reinforcement body comprises the carcass and a belt located radially between the carcass and the tread. The carcass comprises at least one carcass ply. The carcass ply includes carcass cords as reinforcing cords. The carcass cords are inclined with respect to the equatorial plane. The belt comprises at least one belt ply. The belt ply includes belt cords as reinforcing cords. The belt cords are inclined with respect to the tire equatorial plane. The cord reinforcement comprises a layered structure consisting of at least two layers arranged radially on the radially inner side of the tread. The layered structure is composed of the carcass, or the carcass and the belt. The tag member is embedded inside the tread at the bottom of the groove. The tag member is positioned such that the longitudinal direction of the electronic component extends from the tire equatorial plane toward the edge of the tread. [Effects of the Invention]
[0006] According to the present invention, a bias tire can be obtained that can ensure a good communication environment while suppressing the reduction in durability caused by the incorporation of electronic components. [Brief explanation of the drawing]
[0007] [Figure 1] This is an exploded view showing a portion of the tread surface of a bias tire according to one embodiment of the present invention. [Figure 2] This is a cross-sectional view along line II-II in Figure 1. [Figure 3]This is a schematic diagram illustrating the structure of the code reinforcement. [Figure 4] This is a plan view of the tag component. [Figure 5] This is a cross-sectional view along the VV line in Figure 4. [Figure 6] This is a diagram illustrating the arrangement of electronic components. [Figure 7] A cross-sectional view showing a part of a bias tire according to another embodiment of the present invention. [Figure 8] This is a schematic diagram illustrating a modified example of a code reinforcement. [Modes for carrying out the invention]
[0008] The present invention will now be described in detail, with reference to drawings as appropriate, based on preferred embodiments.
[0009] The tire of this invention is mounted on a rim. Air is filled inside the tire, and the internal pressure of the tire is regulated. A tire mounted on a rim is also called a tire-rim assembly. A tire-rim assembly comprises a rim and a tire mounted on this rim.
[0010] In this 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 referred to as the standard state.
[0011] In this invention, unless otherwise specified, the dimensions and angles of each part of the tire are measured under normal conditions. The dimensions and angles of each part of the tire in the meridional cross-section, which cannot be measured when the tire is mounted on a standard rim, are measured at the tire's cross-section, obtained by cutting the tire along a plane containing the axis of rotation. In this measurement, the tire is set so that the distance between the left and right beads matches the distance between the beads in a tire mounted on a standard rim. The tire's structure, which cannot be confirmed when the tire is mounted on a standard rim, is confirmed at the aforementioned cross-section.
[0012] The standard rim means the rim defined in the standards that the tire relies on. The "Standard Rim" in the JATMA standard, the "Design Rim" in the TRA standard, and the "Measuring Rim" in the ETRTO standard are standard rims.
[0013] The standard internal pressure means the internal pressure defined in the standards that the tire relies on. The "Maximum Air Pressure" in the JATMA standard, the "Maximum Value" published in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the TRA standard, and the "INFLATION PRESSURE" in the ETRTO standard are standard internal pressures.
[0014] The standard load means the load defined in the standards that the tire relies on. The "Maximum Load Capacity" in the JATMA standard, the "Maximum Value" published in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the TRA standard, and the "LOAD CAPACITY" in the ETRTO standard are standard loads.
[0015] In the present invention, the "rim diameter designation" is the "rim diameter designation" included in the "tire designation" defined in JIS D4202 "Automobile Tires - Designation and Dimensions".
[0016] In the present invention, among the elements constituting the tire, the 300% modulus of the element made of crosslinked rubber means the tensile stress at 300% elongation defined in JIS K6251. The 300% modulus is measured in accordance with the provisions of JIS K6251. In this measurement, the test piece is sampled from the tire with its longitudinal direction aligned with the circumferential direction of the tire. When a test piece cannot be sampled from the tire, a test piece is sampled from a sheet-like crosslinked rubber (hereinafter also referred to as a rubber sheet) obtained by pressurizing and heating the rubber composition used for forming the element to be measured at a temperature of 170°C for 12 minutes. In the present invention, the 300% modulus is represented by the 300% modulus at 23°C.
[0017] In the present invention, the tread portion of a tire is the portion of the tire that contacts the road surface. The bead portion is the portion of the tire that is fitted to a rim. The sidewall portion is the portion of the tire that bridges between the tread portion and the bead portion. A tire includes, as parts, a tread portion, a pair of bead portions, and a pair of sidewall portions. The tread portion is the portion that includes a tread as a component. The sidewall portion is the portion that includes a sidewall as a component. The bead portion is the portion that includes a bead as a component.
[0018] In the present invention, the thickness of a tire is represented by the thickness from the inner surface to the outer surface of the tire. The thickness of the tire is measured along the normal line of the inner surface of the tire in the meridian cross-section of the tire.
[0019] [Findings underlying the present invention] For example, bias tires are often used for agricultural machinery. Agricultural machinery travels on fields with different road surface conditions, such as soft roads and fields composed of dry soil. The tread pattern of a tire for agricultural machinery is very different from that of a tire traveling on a paved road surface.
[0020] Lugs are provided on the tread portion of a tire for agricultural machinery so as to exhibit traction and pulling force according to the field environment. The land ratio of this tire is small, and the lugs have a considerable height. In a general bias tire (hereinafter, general tire.) without lugs, the rigidity of the sidewall portion tends to be higher than that of the tread portion, but in the case of this tire, the rigidity of the sidewall portion tends to be lower than that of the tread portion.
[0021] Tires absorb road surface irregularities by flexing. In the case of lugged tires, as mentioned above, the sidewall, which has lower rigidity than the tread, is the main part that flexes, absorbing road surface irregularities. Placing electronic components such as RFID tags on the sidewall, as is done with conventional tires, may compromise the tire's durability.
[0022] Therefore, in order to obtain a bias tire that can suppress the reduction in durability caused by the incorporation of electronic components while ensuring a good communication environment, the inventors considered the rigidity of the tire and examined the position in which to incorporate electronic components, and have completed the invention described below.
[0023] [Summary of Embodiments of the Invention] The present invention relates to a tire comprising a pair of beads, a cord reinforcement body spanning between the pair of beads and including reinforcing cords, a tread located radially outward from the cord reinforcement body, a pair of sidewalls located axially outward from the cord reinforcement body, and a tag member including electronic components, wherein the tread comprises a plurality of lugs separated by grooves and arranged circumferentially, the ratio of the lug height of each lug to the minimum thickness of the portion of the tire including the sidewalls is 3.3 or more, the cord reinforcement body comprises a carcass spanning between the pair of beads, or the cord reinforcement body comprises the carcass and a belt located radially between the carcass and the tread, and the carcass comprises at least one carcass ply A bias tire comprising the following features: the carcass ply includes carcass cords as reinforcing cords, the carcass cords are inclined with respect to the equatorial plane; the belt comprises at least one belt ply, the belt ply includes belt cords as reinforcing cords, the belt cords are inclined with respect to the tire equatorial plane; the cord reinforcement comprises a layer structure consisting of at least two layers arranged radially on the radially inner side of the tread; the layer structure is composed of the carcass, or the carcass and the belt; the tag member is embedded inside the tread at the bottom of the groove; and the tag member is positioned such that the longitudinal direction of the electronic component extends from the tire equatorial plane toward the edge of the tread.
[0024] The bias tire of the present invention can ensure a good communication environment while suppressing the reduction in durability caused by the incorporation of electronic components. Although the mechanism by which this effect is achieved is not yet clear, it is presumed to be as follows.
[0025] The bias tire of the present invention has multiple lugs in its tread. The lugs increase the rigidity of the tread. The lugs have a lug height of 3.3 times or more the minimum thickness of the sidewall. The rigidity of the tread is higher than that of the sidewall. Deflection is suppressed in the tread. The sidewall flexes more easily than the tread. Tag members containing electronic components are embedded in the tread, which is less prone to flexing and distortion, rather than in the sidewall, which is more prone to flexing and distortion. This bias tire can suppress the generation of distortion caused by the embedded electronic components. During turns, the sidewall may hit curbs or other obstacles, and the risk of damage to the sidewall is higher than that of the tread. Since electronic components are embedded in the tread, the risk of damage to the electronic components is lower compared to when they are embedded in the sidewall. The tag components are embedded within the tread at the bottom of the grooves between the lugs, rather than directly beneath the lugs. This bias tire maintains a good communication environment for electronic components. The electronic components in this bias tire can perform their functions to the fullest. Multiple lugs are arranged in the circumferential direction on the tread. The tread may deform so that the grooves between the circumferentially aligned lugs become inwardly recessed. The tag members are positioned on the tread so that the length direction of the electronic components is approximately oriented in the axial direction. This suppresses the concentration of strain on the electronic components. The risk of damage to electronic components due to tread deformation is reduced. This bias tire can ensure a good communication environment while suppressing the reduction in durability caused by the incorporation of electronic components.
[0026] Preferably, the cord reinforcement is composed of the carcass and the belt, the belt ply is the outermost layer in the radial direction of the layer structure, and the electronic components are positioned away from the edges of the belt ply. This suppresses the concentration of strain on the electronic components and the edges of the belt ply. The risk of damage to electronic components due to deformation of the tread is reduced.
[0027] Preferably, the cord reinforcement is composed of the carcass, and the carcass ply comprises a ply body spanning between a pair of beads, the first bead and the second bead; a first folded portion connected to one end of the ply body and folded back at the first bead; and a second folded portion connected to the other end of the ply body and folded back at the second bead, wherein the end of the first folded portion is laminated to the ply body on the second bead side beyond the tire equator, and the end of the second folded portion is laminated to the first folded portion on the first bead side beyond the tire equator, and the second folded portion is the outermost layer in the radial direction of the layer structure, and the electronic components are arranged away from the end of the second folded portion. As a result, the ply body, the first folded portion and the second folded portion, located radially inward of the tread, effectively increase the rigidity of the tread. Deformation of the tread during driving is suppressed. The concentration of strain on electronic components caused by tread deformation is suppressed. Since electronic components are also positioned away from the edge of the second folded portion that constitutes the outermost layer of the layered structure, the concentration of strain on the electronic components and the edge of the folded portion is also suppressed. The risk of damage to electronic components due to tread deformation is reduced.
[0028] Preferably, the angle that the longitudinal direction of the electronic component makes with respect to the tire's equatorial plane is between 70 and 110 degrees. This effectively suppresses the concentration of strain on the electronic component, reducing the risk of damage to the electronic component due to deformation of the tread.
[0029] Preferably, the reinforcing cord included in the outermost radial layer of the layer structure is an organic fiber cord. This suppresses the impact of the reinforcing cord, which is close to the electronic component, on the electronic component's communication environment. The electronic component of this bias tire can fully perform its function.
[0030] Preferably, the tread comprises a center portion and a side portion located axially outward from the center portion, wherein the side portion is thicker than the center portion at the bottom of the groove, and the tag member is embedded inside the side portion. In this case, it is more preferable that the ratio WE / WT of the axial distance WE from the tire equatorial plane to the boundary between the center portion and the side portion to the axial distance WT from the tire equatorial plane to the edge of the tread is 20% or more and 30% or less. This allows electronic components to be placed on the side portion where the risk of trauma is low. The electronic components can fully perform their functions. The concentration of strain on the electronic components is suppressed. The risk of damage to electronic components due to deformation of the tread portion is also reduced.
[0031] The bias tire of the present invention can ensure a good communication environment while suppressing the reduction in durability caused by the incorporation of electronic components, and can be suitably used as a bias tire for agricultural machinery. Among bias tires for agricultural machinery, the bias tire of the present invention can be suitably used as a rear tire with a nominal rim diameter of 20 inches or more. From this viewpoint, preferably, the tire is a tire for agricultural machinery. More preferably, the tire is mounted on the rear wheel of the agricultural machinery, and the nominal rim diameter of the rim on which the tire is assembled is 20 inches or more.
[0032] According to the present invention, a bias tire can be obtained that ensures a good communication environment while suppressing the reduction in durability caused by the incorporation of electronic components. This will be explained in detail below using the bias tire shown in Figure 1 as an example.
[0033] [Details of the Embodiments of the Invention] Figures 1 and 2 show a part 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 cultivators, rough terrain transport vehicles, and agricultural implements. This tire 2 is suitable for driving on soft roads and fields such as farmland.
[0034] Figure 1 is a plan view (i.e., unfolded view) of the tread surface 4 of tire 2. Figure 1 shows the tread pattern of tire 2. In Figure 1, the dashed line EL extending radially represents the equatorial plane of tire 2 (hereinafter also called the tire equatorial plane). The position indicated by the symbol TE is the edge of the tread surface 4. In this invention, the edge TE of the tread surface 4 is also called the tread edge.
[0035] The direction indicated by the double arrow AD is the axial direction of tire 2. The axial direction of tire 2 means the direction parallel to the rotation axis of tire 2. In the axial direction, the direction away from the equatorial plane is the axial outward direction of tire 2, and the direction towards the equatorial plane is the axial inward direction of tire 2. The direction indicated by the double arrows CD represents the circumferential direction of tire 2. The direction indicated by arrow CD1 is the leading side of tire 2, and the direction indicated by arrow CD2 is the trailing side. As tire 2 moves forward in the field, it makes contact with the road surface from the leading side to the trailing side.
[0036] Figure 2 shows a portion of the cross-section of tire 2 along the line II-II in Figure 1. Although the line II-II in Figure 1 is not included in the plane containing the rotation axis of tire 2, the cross-section representing the internal structure of tire 2 shown in Figure 2 corresponds to the cross-section of tire 2 along the plane containing the rotation axis of tire 2 (hereinafter referred to as the meridian cross-section). The direction indicated by the double arrow RD is the radial direction of tire 2. The direction indicated by arrow RD1 is the radially inward direction of tire 2, and the direction indicated by arrow RD2 is the radially outward direction of tire 2. The position indicated by the symbol Eq is the equator of tire 2. Equator Eq is the intersection of the equatorial plane and the tread surface 4, and is the radial outer edge of tire 2.
[0037] In Figure 2, tire 2 is mounted on rim R. Rim R is a standard rim. For example, air is filled inside tire 2, and the internal pressure is adjusted. Although not shown in the diagram, a tube is inserted inside tire 2, and air is filled inside this tube. Tire 2 is a tube type. Tire 2 may also be a tubeless type.
[0038] The tire 2 comprises a tread 6, a pair of sidewalls 8, a pair of beads 10, a cord reinforcement 12, and a tag member 14.
[0039] The tread 6 is located radially outward of the cord reinforcement 12. The tread 6 is in contact with the road surface. The outer surface of the tread 6 includes the aforementioned tread surface 4. The tread 6 is the main element of the tread section T. The tread section T includes the tread 6. Tread 6 is made of cross-linked rubber. Without going into detail, Tread 6 is composed of cross-linked rubber commonly used for the treads of bias tires.
[0040] The tread 6 comprises a plurality of lugs 18 separated by grooves 16. The plurality of lugs 18 are arranged in the circumferential direction. The lugs 18 protrude outward from the bottom 20 of the grooves 16. The top surfaces 22 of the lugs 18 are included in the tread surface 4. The tread surface 4 includes the top surfaces 22 of the plurality of lugs 18 provided on the tread 6. The portion of the tread surface 4 other than the top surfaces 22 is the groove 16.
[0041] The ratio of the total area of the top surfaces 22 of the multiple lugs 18 included in the tread surface 4 to the area of the tread surface 4 is the land ratio. This land ratio is determined in the unfolded view of the tread surface 4. The land ratio of this tire 2 is 50% or less. The land ratio of this tire 2 is smaller than that of a lugless tire, such as a passenger car tire.
[0042] In Figure 2, the dashed line TBL represents the virtual outer surface of the tread 6, assuming that no lugs 18 are provided on the tread 6. The bottom 20 of the groove 16 is included in the virtual outer surface TBL. The lug height of the lug 18 is represented by the height from the bottom of the groove 16 to the top surface of the lug 18. The lug height of the lug 18 is set appropriately according to the specifications of the tire 2.
[0043] In Figure 2, the length indicated by the double arrow HR is the lug height of lug 18 on the equatorial plane. The lug height HR is measured along the equatorial plane. In this invention, the ratio HR / Tn of the lug height of lug 18 to the minimum thickness Tn of the sidewall portion S (described later) is set in the range of 3.3 to 18.
[0044] The lug 18 includes the edge TE of the tread surface 4, in other words, the edge TE of the tread 6. The lug 18 has a side surface 24 that extends radially inward from the edge TE of the tread 6. The edge TE of the tread 6 is the boundary between the top surface 22 of the lug 18 and its side surface 24. When the corner formed by the top surface 22 and the side surface 24 is rounded, as in the lug 18 of this tire 2, the edge TE of the tread 6 is represented by the intersection of the extension line LT of the top surface 22 and the extension line LS of the side surface 24.
[0045] Of the left and right tread ends TE of the tread 6, the end TE indicated by symbol TE1 is also called the first end, and the end TE indicated by symbol TE2 is also called the second end. In the tread 6 shown in Figure 1, one end TE located in the direction indicated by arrow AD1 is the first end TE1. The other end TE located in the direction indicated by arrow AD2 is the second end TE2. The end TE located in the direction indicated by arrow AD1 may be called the second end TE2, and the end TE located in the direction indicated by arrow AD2 may be called the first end TE1.
[0046] As mentioned above, the tread 6 of this tire 2 has multiple lugs 18. Each of the multiple lugs 18 has a leading end 26 located on the equatorial plane and a trailing end 28 located on the edge TE side of the tread 6. The aforementioned lug height HR is the height of the leading end 26. The aforementioned side surface 24 is included in the trailing end 28 of the lug 18.
[0047] The lug 18 extends from the leading edge 26 toward the trailing edge 28. In the circumferential direction, the leading edge 26 is located on the side of the trailing edge 28 that makes contact with the road surface. In a tire 2 in motion, the lug 18 makes contact with the road surface from the leading edge 26 toward the trailing edge 28.
[0048] The lugs 18 of this tire 2 include a plurality of first lugs 30 located in the zone between the equatorial plane and the first end TE1 of the tread 6 (hereinafter also called the first zone), and a plurality of second lugs 32 located in the zone between the equatorial plane and the second end TE2 of the tread 6 (hereinafter also called the second zone).
[0049] Multiple first lugs 30 are arranged in the first zone at predetermined intervals in the circumferential direction. The first lugs 30 extend from the equatorial plane toward the first end TE1 of the tread 6. Multiple second lugs 32 are arranged in the second zone at predetermined intervals in the circumferential direction. The second lugs 32 extend from the equatorial plane toward the second end TE2 of the tread 6. The first lug 30 and the second lug 32 are arranged alternately in the circumferential direction. The first lug 30 and the second lug 32 alternately contact the road surface.
[0050] Each sidewall 8 is connected to the tread 6. The sidewall 8 is located radially inward of the tread 6. The sidewall 8 is located axially outward of the cord reinforcement 12. The sidewall 8 is the main element of the sidewall section S. The sidewall section S includes the sidewall 8. The sidewall section S is thinner than the tread section T.
[0051] In Figure 2, the position indicated by the symbol Pn is the position where the sidewall portion S has its minimum thickness. The double arrow Tn represents the thickness of the sidewall portion S at position Pn, i.e., the minimum thickness of the sidewall portion S.
[0052] Sidewall 8 is made of cross-linked rubber. While not detailed here, sidewall 8 is made of cross-linked rubber commonly used for the sidewalls of bias tires. Sidewall 8 may be made of the same cross-linked rubber as tread 6, or it may be made of a different cross-linked rubber.
[0053] Each bead 10 is located radially inward of the sidewall 8. The bead 10 is the main element of the bead section B. The bead section B includes the bead 10. The bead 10 comprises a core 34 and an apex 36. The core 34 extends in the circumferential direction. Although not shown, the core 34 contains steel wires. The apex 36 is located radially outward from the core 34. The apex 36 is made of cross-linked rubber with high rigidity.
[0054] As previously mentioned, the tire 2 comprises a pair of beads 10. For convenience of explanation, in this specification, the bead 10 located on the first end TE1 side of the tread 6 is called the first bead 10a, and the bead 10 located on the second end TE2 side is also called the second bead 10b. Alternatively, the bead 10 located on the first end TE1 side may be called the second bead 10b, and the bead 10 located on the second end TE2 side may be called the first bead 10a.
[0055] The cord reinforcement 12 is located inside the tread 6 and the pair of sidewalls 8. The cord reinforcement 12 spans between the pair of beads 10.
[0056] Figure 3 shows the configuration of the cord reinforcement 12. The configuration of the cord reinforcement 12 shown in Figure 3 is the configuration of the cord reinforcement 12 on the radially inner side of the tread 6. The direction perpendicular to the plane of the paper in Figure 3 is the radial direction of the tire 2. The front side of the paper is the radially outer side, and the back side is the radially inner side.
[0057] On the radially inner side of the tread 6, the cord reinforcement 12 comprises a plurality of layers 40 arranged in the radial direction. The plurality of radially arranged layers 40 constitute a layer structure 42. This layer structure 42 of the tire 2 is composed of three radially arranged layers 40. This layer structure 42 may consist of at least two layers 40, or it may consist of four or more layers 40. The cord reinforcement 12 comprises a layer structure 42 on the radially inner side of the tread 6, consisting of at least two radially arranged layers 40.
[0058] Each layer 40 constituting the layer structure 42 includes a number of parallel reinforcing cords 44. In Figure 3, for ease of explanation, the reinforcing cords 44 are represented by solid lines, but the reinforcing cords 44 are covered with topping rubber 46. The cord reinforcement body 12 includes the reinforcing cords 44.
[0059] The cord reinforcement 12 of this tire 2 comprises a carcass 48 and a belt 50. More specifically, the cord reinforcement 12 is composed of a carcass 48 and a belt 50. The aforementioned layer structure 42 is composed of a carcass 48 and a belt 50.
[0060] The carcass 48 spans between a pair of beads 10. The carcass 48 comprises at least one carcass ply 52. The carcass 48 of this tire 2 comprises two carcass plies 52. Of the two carcass plies 52 that make up the carcass 48, the carcass ply 52 located radially inward on the radially inward side of the tread 6 is also called the inner ply 54, and the carcass ply 52 located radially outward is also called the outer ply 56. The carcass 48 may comprise three or more carcass plies 52.
[0061] Each of the two carcass plies 52 is folded over at its respective bead 10. The carcass plies 52 of this tire 2 are folded over at each bead 10 from the axially inward to the axially outward direction. The carcass plies 52 are roll-up plies. This carcass 48 has two roll-up plies.
[0062] The carcass ply 52 comprises a ply body 58 and a pair of folded portions 60. The ply body 58 spans between a pair of beads 10. Each folded portion 60 is connected to the end of the ply body 58 and is folded over by the bead 10.
[0063] On the radially inner side of the tread 6, the ply body 58 of the outer ply 56 is located radially outward of the ply body 58 of the inner ply 54. The folded portion 60 of the outer ply 56 is located axially inward of the folded portion 60 of the inner ply 54. The end of the folded portion 60 of the outer ply 56 is covered by the folded portion 60 of the inner ply 54. The end of the folded portion 60 of the inner ply 54 is located radially inward of the end of the belt 50. The end of the folded portion 60 of the inner ply 54 is positioned away from the end of the belt 50. The end of the folded portion 60 of the inner ply 54 is covered by the sidewall 8.
[0064] As shown in Figure 3, each carcass ply 52 contains a number of parallel carcass cords 62. The carcass 48 constitutes part of the cord reinforcement 12. The carcass cords 62 are also the aforementioned reinforcement cords 44. The carcass ply 52 contains the carcass cords 62 as reinforcement cords 44. In each carcass ply 52, the carcass cords 62 are inclined with respect to the equatorial plane. The carcass 48 has a bias structure. The tire 2 is equipped with a bias-structured carcass 48.
[0065] As shown in Figure 3, the direction of the inclination of the carcass cord 62 contained in the inner ply 54 is opposite to the direction of the inclination of the carcass cord 62 contained in the outer ply 56.
[0066] In Figure 3, the angle indicated by the symbol α1 is the angle that the carcass code 62 contained in the inner ply 54 makes with respect to the equatorial plane. The angle indicated by the symbol α2 is the angle that the carcass code 62 contained in the outer ply 56 makes with respect to the equatorial plane.
[0067] The angle α1 that the carcass code 62 of the inner ply 54 makes with respect to the equatorial plane is preferably 25 degrees or more and 45 degrees or less. The angle α2 that the carcass code 62 of the outer ply 56 makes with respect to the equatorial plane is preferably 25 degrees or more and 45 degrees or less.
[0068] The carcass cord 62 is a cord made of organic fibers (hereinafter referred to as organic fiber cord). Examples of organic fibers include nylon fibers, rayon fibers, polyester fibers, and aramid fibers. In this tire 2, among the organic fiber cords, a cord made of nylon fibers is preferably used as the carcass cord 62.
[0069] The belt 50 is positioned radially between the carcass 48 and the tread 6. The belt 50 is laminated on the carcass 48 on the radially inner side of the tread 6. The belt 50 comprises at least one belt ply. The belt 50 of this tire 2 is composed of one belt ply 64. The belt 50 may be composed of two or more belt plies 64.
[0070] As shown in Figure 3, the belt ply 64 includes a number of parallel belt cords 66. The belt 50 constitutes part of the cord reinforcement 12. The belt cords 66 are also reinforcement cords 44. The belt ply 64 includes the belt cords 66 as reinforcement cords 44. In the belt ply 64, the belt cords 66 are inclined with respect to the equatorial plane.
[0071] As shown in Figure 3, the direction of the inclination of the belt cord 66 included in the belt ply 64 is opposite to the direction of the inclination of the carcass cord 62 included in the ply body 58 of the outer ply 56. The direction of the inclination of the belt cord 66 may be the same as the direction of the inclination of the carcass cord 62 included in the ply body 58 of the outer ply 56.
[0072] In Figure 3, the angle indicated by the sign β is the angle that the belt cord 66 included in the belt ply 64 makes with respect to the equatorial plane. The angle β that the belt cord 66 of the belt ply 64 makes with respect to the equatorial plane is preferably 20 degrees or more and 45 degrees or less.
[0073] The belt cord 66 is an organic fiber cord. Examples of organic fibers include nylon fibers, rayon fibers, polyester fibers, and aramid fibers. In this tire 2, among the organic fiber cords, a cord made of nylon fibers is preferably used as the belt cord 66.
[0074] The tag member 14 is located between the bottom 20 of the groove 16 and the cord reinforcement 12. More specifically, the tag member 14 is embedded inside the tread 6 at the bottom 20 of the groove 16. As shown in Figure 2, the tag member 14 of this tire 2 is positioned away from the cord reinforcement 12 by interposing a layer made of cross-linked rubber that constitutes the tread 6 between the cord reinforcement 12 and the tag member 14. Alternatively, the tag member 14 may be embedded inside the tread 6 by covering the cord reinforcement 12 to which the tag member 14 is directly attached with the tread 6, without the aforementioned layer being interposed.
[0075] In this tire 2, one tag member 14 is embedded inside the tread 6 in the first zone on the first bead 10a side. Multiple tag members 14 may be provided in both the first zone on the first bead 10a side and the second zone on the second bead 10b side. From the viewpoint of suppressing a decrease in durability, it is preferable that the tag member 14 is provided in either the first zone or the second zone, in other words, on either the first bead 10a or the second bead 10b side. In this tire 2, multiple tag members 14 may be arranged circumferentially on one bead 10 side, but from the viewpoint of suppressing a decrease in durability, it is sufficient to provide only one tag member 14 on one bead 10 side.
[0076] Figure 4 is a plan view of the tag member 14. Figure 5 is a cross-sectional view along the VV line in Figure 4. The tag member 14 is plate-shaped. The tag member 14 is long in the length direction and short in the width direction.
[0077] The tag member 14 includes an electronic component 68. In Figure 4, the electronic component 68 is shown by a solid line for ease of explanation, but its entirety is covered by a protective body 70. The tag member 14 comprises the electronic component 68 and the protective body 70. The electronic component 68 is located in the center of the tag member 14. The protective body 70 is made of cross-linked rubber. In this tire 2, consideration was given to creating a good communication environment, and the protective body 70 is made of cross-linked rubber with high electrical resistance. The protective body 70 is made of highly insulating rubber.
[0078] The cross-linked rubber constituting the protective body 70 of the tire 2 has a 300% modulus higher than that of the cross-linked rubber constituting the tread 6. This allows the protective body 70 to deform in accordance with the bending deformation of the tire 2 during rolling, and also suppresses the occurrence of specific strains in the protective body 70. From this viewpoint, it is preferable that the 300% modulus Mp of the cross-linked rubber constituting the protective body 70 is 1.1 times or more and 1.6 times or less of the 300% modulus Mt of the cross-linked rubber constituting the tread 6.
[0079] Electronic component 68 is a small and lightweight electronic component. Without going into detail, this component 68 in tire 2 is an RFID tag 76, consisting of a semiconductor chip 72 that integrates a transmitting / receiving circuit, control circuit, memory, etc., and an antenna 74. When the RFID tag 76 receives a query radio wave, it uses this as electrical energy to transmit various data stored in its memory as a response radio wave. The RFID tag 76 is a type of passive radio frequency identification transponder.
[0080] The RFID tag 76 on tire 2 comprises a semiconductor chip 72 and a pair of antennas 74. The semiconductor chip 72 is located between the pair of antennas 74. Each antenna 74 extends from the semiconductor chip 72 in the longitudinal direction of the tag member 14.
[0081] The tag member 14 is a plate-shaped member in which an electronic component 68 is covered with cross-linked rubber. From the viewpoint of reducing the risk of damage to the electronic component 68 and forming a good communication environment, the thickness of the tag member 14 in the meridional cross-section of the tire 2 is preferably 1.0 mm or more and 2.5 mm or less. This 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 72 that constitutes the RFID tag 76. The length TL of the tag member 14 before it is embedded in tire 2 is 60 mm or more and 80 mm or less. The width TW is 10 mm or more and 20 mm or less.
[0082] In Figure 4, the length indicated by the double arrow ML is the maximum length of the electronic component 68. The maximum length ML is obtained by identifying the rectangular frame (the dashed line FR in Figure 4) that the electronic component 68 circumscribes, and is represented by the maximum distance between the contact points that abut the frame.
[0083] In Figure 4, the position indicated by the symbol PM is one end that specifies the maximum length ML of the electronic component 68, and the position indicated by the symbol PL is the other end that specifies this maximum length ML. The maximum length ML is represented by the length of the line segment connecting the ends PM and PL of the electronic component 68. The solid line LD is a straight line that includes the line segment connecting the ends PM and PL of the electronic component 68. The direction in which this straight line LD extends represents the length direction of the electronic component 68. In this invention, the length direction of the electronic component 68 is represented by the direction of the straight line that passes through the end PM and the other end PL of the electronic component 68 at which the length of the electronic component 68 is maximized. In other words, the length direction of the electronic component 68 is represented by the direction of the line segment that represents the maximum length of the electronic component 68.
[0084] Figure 6 illustrates the arrangement of the electronic component 68. Figure 6 shows the bottom 20 of the groove 16 where the electronic component 68 is located. In this tire 2, one end PM of the line segment representing the maximum length ML of the electronic component 68 is located on the equatorial plane side, and the other end PL of the electronic component 68 is located on the TE side of the tread 6. The tag member 14 of this tire 2 is arranged such that the longitudinal direction of the electronic component 68 extends from the equatorial plane toward the TE side of the tread 6. In other words, the longitudinal direction of the electronic component 68 extends approximately in the axial direction.
[0085] As mentioned above, the tread 6 of this tire 2 is provided with multiple lugs 18. The lugs 18 increase the rigidity of the tread section T. The lugs 18 have a lug height HR of 3.3 times or more the minimum thickness Tn of the sidewall section S. The rigidity of the tread section T is higher than the rigidity of the sidewall section S. Deflection is suppressed in the tread section T. The sidewall section S flexes easily relative to the tread section T. The tag member 14, which includes the electronic component 68, is embedded inside the tread 6, which is less prone to flexing and distortion, rather than inside the sidewall 8, which is more prone to flexing and distortion. This tire 2 can suppress the generation of distortion caused by the built-in electronic component 68.
[0086] During turns, the sidewall section S may come into contact with curbs or embankments. The risk of damage to the sidewall section S is higher than that of the tread section T. Since the electronic components 68 are embedded in the tread section T, the risk of damage to the electronic components 68 is lower compared to when the electronic components are embedded in the sidewall section S.
[0087] Since the tag member 14 is embedded inside the tread 6 at the bottom 20 of the groove 16 between the lugs 18, rather than directly beneath the lugs 18, this tire 2 can maintain a good communication environment for the electronic components 68. The electronic components 68 in this tire 2 can fully perform their functions.
[0088] Multiple lugs 18 provided on the tread 6 are arranged in the circumferential direction. The tread portion may deform so that the grooves 16 between the circumferentially arranged lugs 18 become indented inward. As described above, the tag member 14 is positioned on the tread portion T such that the longitudinal direction of the electronic component 68 is oriented approximately in the axial direction. This suppresses the concentration of strain on the electronic component 68. The risk of damage to the electronic component 68 due to deformation of the tread portion T is reduced.
[0089] This tire 2 can ensure a good communication environment while suppressing the reduction in durability caused by the incorporation of electronic components.
[0090] As mentioned above, the cord reinforcement 12 of this tire 2 is composed of a carcass 48 and a belt 50. In this tire 2, the aforementioned layer structure 42 is composed of three layers arranged radially: the ply body 58 of the inner ply 54, the ply body of the outer ply 56, and the belt ply 64. In the three-layer structure 42, the outermost layer 40 in the radial direction is the belt ply 64. In other words, the belt ply 64 is the outermost layer 40 in the radial direction of the layer structure 42.
[0091] As shown in Figure 2, the electronic component 68 of this tire 2 is positioned away from the edge of the belt ply 64 that constitutes the outermost layer 40 of the layer structure 42. This suppresses the concentration of strain on the electronic component 68 and the edge of the belt ply 64. The risk of damage to the electronic component 68 due to deformation of the tread portion T is reduced. From this viewpoint, if the cord reinforcement 12 is composed of a carcass 48 and a belt 50, and the belt ply 64 is the outermost layer 40 in the radial direction of the layer structure 42, it is preferable that the electronic component 68 is positioned away from the edge of the belt ply 64. In this case, the electronic component 68 may be located axially outward from the edge of the belt ply 64, or axially inward from the edge of the belt ply 64. From the viewpoint of positioning the electronic component 68 away from the easily flexible sidewall portion S and effectively reducing the risk of damage to the electronic component 68, it is preferable that the electronic component 68 be located axially inward from the edge of the belt ply 64, as shown in Figure 2.
[0092] As mentioned above, the belt cord 66 included in the belt ply 64 is an organic fiber cord. In other words, the reinforcing cord 44 included in the outermost radial layer 40 of the layer structure 42 is an organic fiber cord. This suppresses the impact of the reinforcing cord 44, which is in close proximity to the electronic component 68, on the communication environment of the electronic component 68. The electronic component 68 of this tire 2 can fully perform its function. From this viewpoint, it is preferable that the reinforcing cord 44 included in the outermost radial layer 40 of the layer structure 42 is an organic fiber cord.
[0093] In Figure 6, angle θ is the angle between the straight line LD representing the length direction of the electronic component 68 and the dashed line EL representing the equatorial plane. In the present invention, this angle θ is the angle that the length direction of the electronic component 68 makes with respect to the equatorial plane. As described above, by arranging the tag member 14 on the tread portion T such that the longitudinal direction of the electronic component 68 is oriented approximately in the axial direction, the concentration of strain on the electronic component 68 is suppressed. This reduces the risk of damage to the electronic component 68 due to deformation of the tread portion T. From this viewpoint, the angle θ that the longitudinal direction of the electronic component 68 makes with respect to the equatorial plane is preferably 70 degrees or more and 110 degrees or less, more preferably 80 degrees or more and 100 degrees or less, and even more preferably 85 degrees or more and 95 degrees or less.
[0094] In the present invention, the thickness of the tread 6 at the bottom 20 of the groove 16 (hereinafter referred to as the groove bottom thickness of the tread 6) is measured along the normal to the outer surface of the cord reinforcement 12. As shown in Figure 2, the groove bottom thickness of the tread 6 is thin near the equatorial plane and thicker in the axially outer portion of the tread 6. The portion of the tread 6 of this tire 2 that is axially outer from the equatorial plane comprises a center portion 78 located on the equatorial plane side and a side portion 80 located axially outer from the center portion 78. At the bottom 20 of the groove 16, the side portion 80 is thicker than the center portion 78.
[0095] In Figure 2, the length indicated by the double-headed arrow TR represents the groove bottom thickness of the tread 6 at the equatorial plane. The position indicated by the symbol PB represents the boundary between the center portion 78 and the side portion 80, and the length indicated by the double-headed arrow TB represents the groove bottom thickness of the tread 6 at this boundary PB. In this invention, the boundary PB between the center portion 78 and the side portion 80 is represented at a position where the groove bottom thickness TB of the tread 6 is three times the groove bottom thickness TR of the tread 6 on the equatorial plane. The portion between the equatorial plane and the boundary PB is the center portion 78, and the axially outer portion of the boundary PB is the side portion 80. The thickness of the center portion 78 at the bottom 20 of the groove 16, that is, the groove bottom thickness of the center portion 78, is represented by the groove bottom thickness TR of the tread 6 on the equatorial plane, as described above.
[0096] As mentioned above, the side portion 80 is thicker than the center portion 78 at the bottom 20 of the groove 16. The risk of injury at the bottom 20 of the groove 16 is low at the side portion 80 and high at the center portion 78. As shown in Figure 2, the tag member 14 is embedded inside the side portion 80. This allows the electronic component 68 to be placed in the side portion 80, where the risk of injury is low. The electronic component 68 can fully perform its function. The concentration of strain on the electronic component 68 is suppressed. The risk of damage to the electronic component 68 due to deformation of the tread portion T is also reduced. From this viewpoint, it is preferable that the tag member 14 provided at the bottom 20 of the groove 16 be embedded inside the side portion 80. In other words, it is preferable that the tag member 14 be embedded inside the side portion 80 at the bottom 20 of the groove 16.
[0097] In Figure 2, the double arrow WT represents the axial distance from the equatorial plane to the edge TE of the tread 6. The double arrow WB represents the axial distance from the equatorial plane to the boundary PB between the center section 78 and the side section 80.
[0098] The ratio WB / WT of the axial distance WB from the equatorial plane to the boundary PB between the center portion 78 and the side portion 80, and the axial distance WT from the equatorial plane to the edge TE of the tread 6, is preferably 20% to 30%. This ensures that the bottom portion 20 of the grooves 16 of the tread 6 (hereinafter referred to as the groove bottom portion of the tread 6) has an appropriate thickness distribution. Since the strain generated in the groove bottom portion of the tread 6 is effectively dispersed, the concentration of strain on the electronic components 68 embedded in the side portion 80 is suppressed. The risk of damage to the electronic components 68 due to deformation of the tread portion T is also reduced. From this viewpoint, the ratio WB / WT is more preferably 22% to 28%, and even more preferably 24% to 26%.
[0099] In Figure 2, the position indicated by the symbol GC is the center of the electronic component 68 (specifically, the RFID tag 76). The center GC is represented by the center of the circle circumscribing the semiconductor chip 72 of the RFID tag 76. The center GC is confirmed in the meridian cross section. The solid line LG is the normal to the outer surface of the code reinforcement 12 passing through the center GC of the electronic component 68. The length indicated by the double arrow TA is the groove bottom thickness of the tread 6 at the center GC of the electronic component 68. The groove bottom thickness TA is measured along the normal LG to the outer surface of the code reinforcement 12. As mentioned above, the electronic component 68 is embedded in the side portion 80. The thickness of the side portion 80 at the bottom 20 of the groove 16, that is, the groove bottom thickness of the side portion 80, is represented by the groove bottom thickness TA of the tread 6 at the center GC of the electronic component 68. The length indicated by the double arrow TS is the distance from the center GC of the electronic component 68 to the bottom 20 of the groove 16. The length indicated by the double arrow TU is the distance from the center GC of the electronic component 68 to the cord reinforcement 12. Distances TS and TU are measured along the normal LG of the outer surface of the cord reinforcement 12. The sum of distances TS and TU is equal to the groove bottom thickness TA of the side portion 80.
[0100] Distance TS is also called the outer layer thickness of the side portion 80 at the location of the electronic component 68, and distance TU is also called the inner layer thickness of the side portion 80 at the location of the electronic component 68. The balance between the outer layer thickness TS and the inner layer thickness TU reflects the position of the electronic component 68 embedded in the side portion 80 in the thickness direction of the side portion 80 at the bottom 20 of the groove 16. The inner layer thickness TU reflects the thickness of the rubber layer interposed between the tag member 14 and the cord reinforcement 12.
[0101] The ratio TA / TR of the groove bottom thickness TA of the side portion 80 to the groove bottom thickness TR of the center portion 78 is preferably 3.5 or more and 5.5 or less. This allows the thicker side portion 80 to effectively contribute to suppressing the concentration of strain on the electronic components 68 embedded in the side portion 80. This tire 2 can reduce the risk of damage to electronic components due to deformation of the tread portion T. From this viewpoint, a ratio TA / TR of 4.0 or more and 5.0 or less is more preferable.
[0102] As shown in Figure 2, the outer layer thickness TS of the side portion 80 is thicker than its inner layer thickness TU. This effectively suppresses the effects of trauma on the electronic components 68 embedded in the side portion 80. The electronic components 68 can fully perform their functions. The concentration of strain on the electronic components 68 is suppressed. The risk of damage to the electronic components due to deformation of the tread portion T is also reduced. From this viewpoint, it is preferable that the outer layer thickness TS of the side portion 80 is thicker than its inner layer thickness TU.
[0103] The ratio of the outer layer thickness TS to the inner layer thickness TU, TS / TU, is preferably between 2.0 and 4.0. By setting the TS / TU ratio to 2.0 or higher, the impact of trauma on the electronic components 68 embedded in the side section 80 is effectively suppressed. The electronic components 68 can fully perform their functions. The concentration of strain on the electronic components 68 is suppressed. The risk of damage to the electronic components due to deformation of the tread section T is also reduced. From this viewpoint, a TS / TU ratio of 2.5 or higher is more preferable. By setting the TS / TU ratio to 4.0 or less, the electronic component 68 is positioned at an appropriate distance from the cord reinforcement 12. The rubber layer interposed between the tag member 14 and the cord reinforcement 12 can effectively contribute to suppressing the concentration of strain between the electronic component 68 and the reinforcing cord 44. From this viewpoint, a TS / TU ratio of 3.5 or less is more preferable.
[0104] Figure 7 is a cross-sectional view showing a part of a bias tire 102 (hereinafter also simply referred to as "tire 102") according to another embodiment of the present invention. Similar to the cross-sectional view shown in Figure 2, the cross-section showing the internal structure of tire 102 shown in Figure 7 corresponds to the meridian cross-section of tire 102. Except for the cord reinforcement 104 of tire 102, it has the same configuration as tire 2 shown in Figures 1 and 2. Elements identical to those of tire 2 are denoted by the same reference numerals, and their descriptions are omitted.
[0105] The cord reinforcement 104 is located inside the tread 6 and the pair of sidewalls 8. The cord reinforcement 104 spans between the pair of beads 10.
[0106] Figure 8 shows the configuration of the cord reinforcement 104. The configuration of the cord reinforcement 104 shown in Figure 8 is the configuration of the cord reinforcement 104 on the radially inner side of the tread 6. The direction perpendicular to the plane of Figure 8 is the radial direction of the tire 102. The front side of the plane is the radially outer side, and the back side is the radially inner side.
[0107] In this tire 102 as well, the cord reinforcement 12 on the radially inner side of the tread 6 comprises multiple layers 106 arranged radially. These multiple radially arranged layers 106 constitute a layer structure 108. The layer structure 108 of this tire 102 is composed of three radially arranged layers 106, similar to the layer structure 42 of the tire 2 described above.
[0108] Each layer 106 constituting the layer structure 108 includes a number of parallel reinforcing cords 110. In Figure 8, for the sake of explanation, the reinforcing cords 110 are represented by solid lines, but the reinforcing cords 110 are covered with topping rubber 112. The cord reinforcement body 104 includes the reinforcing cords 110.
[0109] The cord reinforcement 104 of this tire 102 comprises a carcass 114. More specifically, the cord reinforcement 104 is composed of the carcass 114. The aforementioned layer structure 108 is composed of the carcass 114.
[0110] The carcass 114 spans between a pair of beads 10. The carcass 114 of this tire 102 is composed of one carcass ply 116. This carcass 114 may be composed of multiple carcass plies 116.
[0111] The carcass ply 116 is folded over at each bead 10. The carcass ply 116 of this tire 102 is folded over at each bead 10 from the axially inward to the axially outward direction. The carcass ply 116 is a rolled-up ply.
[0112] The carcass ply 116 comprises a ply body 118 and a pair of folded portions 120. The ply body 118 spans between the first bead 10a and the second bead 10b. Each folded portion 120 is connected to the end of the ply body 118 and folded back at the bead 10. Of the pair of folded portions 120, the folded portion 120 connected to one end of the ply body 118 and folded back at the first bead 10a is the first folded portion 122. Of the pair of folded portions 120, the folded portion 120 connected to the other end of the ply body 118 and folded back at the second bead 10b is the second folded portion 124. The carcass ply 116 comprises a ply body 118, the first folded portion 122, and the second folded portion 124.
[0113] In Figure 7, the end of the first folded portion 122 is laminated onto the ply body 118 on the second bead 10b side, beyond the equatorial plane. The end of the second folded portion 124 is laminated onto the first folded portion 122 on the first bead 10a side, beyond the equatorial plane. The end of the first folded portion 122 is covered by the second folded portion 124. The end of the second folded portion 124 is covered by the tread 6.
[0114] As shown in Figure 8, the carcass ply 116 contains a number of parallel carcass cords 126. The carcass 114 constitutes the cord reinforcement 104. The carcass cords 126 are also the aforementioned reinforcement cords 110. The carcass ply 116 includes the carcass cords 126 as reinforcement cords 110. In the carcass ply 116, the carcass cords 126 are inclined with respect to the equatorial plane. This carcass 114 also has a bias structure.
[0115] In Figure 8, the angle indicated by the symbol α is the angle that the carcass code 126 contained in the ply body 118 of the carcass ply 116 makes with respect to the equatorial plane. The angle α that the carcass code 126 contained in the ply body 118 makes with respect to the equatorial plane is preferably between 25 degrees and 45 degrees.
[0116] As mentioned above, the carcass 114 of this tire 102 is composed of a single carcass ply 116. The angle that the carcass cords 126 included in the ply body 118, the carcass cords 126 included in the first folded portion 122, and the carcass cords 126 included in the second folded portion 124 make with respect to the equatorial plane is the same. The first folded portion 122 and the second folded portion 124 are formed by folding the carcass ply 116 at their respective beads 10. The direction of inclination of the carcass cord 126 included in the first folded portion 122 and the carcass cord 126 included in the second folded portion 124 is opposite to the direction of inclination of the carcass cord 126 included in the ply body 118. The direction of inclination of the carcass cord 126 included in the first folded portion 122 is the same as the direction of inclination of the carcass cord 126 included in the second folded portion 124.
[0117] The carcass cord 126, like the carcass cord 62 mentioned above, is an organic fiber cord. Examples of organic fibers include nylon fibers, rayon fibers, polyester fibers, and aramid fibers. In this tire 2, among the organic fiber cords, a cord made of nylon fiber is preferably used as the carcass cord 126.
[0118] The tag member 14 is located between the bottom 20 of the groove 16 and the cord reinforcement 104. The tag member 14 is embedded inside the tread 6 (specifically, the side portion 80) at the bottom 20 of the groove 16. As shown in Figure 7, the tag member 14 of this tire 102 is provided on the first end TE1 side of the tread 6, i.e., in the first zone. The tag member 14 may also be provided on the second end TE2 side of the tread 6, i.e., in the second zone. In this tire 2, the end of the second folded portion 124 is located in the first zone and is exposed on the outer surface of the cord reinforcement 104. In contrast, the end of the first folded portion 122 is located in the second zone and is covered by the second folded portion 124. From the viewpoint of effectively suppressing the concentration of strain on the electronic component 68, although not shown, it is preferable that the tag member 14 be positioned in the second zone between the bottom 20 of the groove 16 and the cord reinforcement 104.
[0119] As mentioned above, the cord reinforcement 104 of this tire 102 is composed of a carcass 114. The layer structure 108 of this tire 102 is composed of three layers arranged radially: a ply body 118, a first folded portion 122, and a second folded portion 124. The outermost layer 106 in the radial direction of the three-layer structure 108 is the second folded portion 124. In other words, the second folded portion 124 is the outermost layer 106 in the radial direction of the layer structure 108. The electronic component 68 is positioned away from the edge of the second folded portion 124 that constitutes the outermost layer 106 of the layer structure 108, as shown in Figure 7.
[0120] In this tire 2, the ply body 118, the first folded portion 122, and the second folded portion 124, located radially inward of the tread 6, effectively increase the rigidity of the tread portion T. Deformation of the tread portion T during driving is suppressed. Concentration of strain on the electronic component 68 caused by deformation of the tread portion T is suppressed. Moreover, since the electronic component 68 is positioned away from the end of the second folded portion 124, which constitutes the outermost layer 106 of the layer structure 108, concentration of strain on the electronic component 68 and the end of the second folded portion 124 is suppressed. The risk of damage to the electronic component 68 due to deformation of the tread portion T is reduced. From this viewpoint, if the cord reinforcement body 104 is composed of the carcass 114 and the second folded portion 124 covering the end of the first folded portion 122 is the outermost layer 106 of the layer structure 108, it is preferable that the electronic component 68 be positioned away from the end of the second folded portion 124.
[0121] When the electronic component 68 is positioned away from the end of the second folded portion 124, it may be located axially outward from the end of the second folded portion 124, or axially inward from the end of the second folded portion 124. From the viewpoint of positioning the electronic component 68 away from the easily flexible sidewall portion S and effectively reducing the risk of damage to the electronic component 68, it is preferable that the electronic component 68 be located axially inward from the end of the second folded portion 124, as shown in Figure 7.
[0122] As mentioned above, the carcass cord 126 contained in the carcass ply 116 is an organic fiber cord. In other words, the reinforcing cord 110 contained in the outermost radial layer 106 of the layer structure 108 is an organic fiber cord. This suppresses the impact of the reinforcing cord 110, which is close to the electronic component 68, on the communication environment of the electronic component 68. The electronic component 68 of this tire 102 can fully perform its function. From this viewpoint, it is preferable that the reinforcing cord 110 contained in the outermost radial layer 106 of the layer structure 108 is an organic fiber cord.
[0123] As is clear from the above description, the present invention provides a bias tire that can ensure a good communication environment while suppressing the reduction in durability caused by the incorporation of electronic components. The present invention is particularly effective in bias tires for agricultural machinery that travel on soft roads and fields. The bias tire of the present invention can be suitably used as a rear tire with a rim diameter of 20 inches or more among bias tires for agricultural machinery. [Industrial applicability]
[0124] The technology described above, which can suppress the decrease in durability caused by the incorporation of electronic components, can be applied to various types of tires.
[0125] [Note] The present invention includes the following embodiments.
[0126] [1] A tire comprising a pair of beads, a cord reinforcement body including reinforcing cords that spans between the pair of beads, a tread located radially outward from the cord reinforcement body, a pair of sidewalls located axially outward from the cord reinforcement body, and a tag member including electronic components, wherein the tread comprises a plurality of lugs separated by grooves and arranged circumferentially, the ratio of the lug height of each lug to the minimum thickness of the portion of the tire including the sidewalls is 3.3 or more, the cord reinforcement body comprises a carcass that spans between the pair of beads, or the cord reinforcement body comprises the carcass and a belt located radially between the carcass and the tread, the carcass comprises at least one carcass ply A bias tire comprising: the carcass ply includes carcass cords as reinforcing cords, the carcass cords are inclined with respect to the equatorial plane; the belt comprises at least one belt ply, the belt ply includes belt cords as reinforcing cords, the belt cords are inclined with respect to the tire equatorial plane; the cord reinforcement comprises a layer structure consisting of at least two radially aligned layers on the radially inner side of the tread; the layer structure is composed of the carcass, or the carcass and the belt; the tag member is embedded inside the tread at the bottom of the groove; and the tag member is positioned such that the longitudinal direction of the electronic component extends from the tire equatorial plane toward the edge of the tread. [2] The bias tire according to [1] above, wherein the cord reinforcement is composed of the carcass and the belt, the belt ply is the outermost layer in the radial direction of the layer structure, and the electronic components are arranged away from the ends of the belt ply. [3] The bias tire according to [1] above, wherein the cord reinforcement is composed of the carcass, and the carcass ply comprises a ply body spanning between a pair of beads, the first bead and the second bead, a first folded portion connected to one end of the ply body and folded back at the first bead, and a second folded portion connected to the other end of the ply body and folded back at the second bead, wherein the end of the first folded portion is laminated to the ply body on the second bead side beyond the tire equator, the end of the second folded portion is laminated to the first folded portion on the first bead side beyond the tire equator, the second folded portion is the outermost radial layer of the layer structure, and the electronic components are arranged away from the end of the second folded portion. [4] A bias tire according to any of the above [1] to [3], wherein the angle that the longitudinal direction of the electronic component makes with respect to the tire's equatorial plane is 70 degrees or more and 110 degrees or less. [5] The bias tire according to any one of the above [1] to [4], wherein the reinforcing cord included in the outermost radial layer of the layer structure is an organic fiber cord. [6] The bias tire according to any one of [1] to [5] above, wherein the tread comprises a center portion and a side portion located axially outward from the center portion, the side portion being thicker than the center portion at the bottom of the groove, and the tag member being embedded inside the side portion. [7] The bias tire as described in [6] above, wherein the ratio WE / WT of the axial distance WE from the tire equatorial plane to the boundary between the center portion and the side portion to the axial distance WT from the tire equatorial plane to the edge of the tread is 20% or more and 30% or less. [8] A bias tire for agricultural machinery, as described in any of the above [1] through [7]. [9] The bias tire described in [8] above, which is mounted on the rear wheel of the agricultural machine and has a nominal rim diameter of 20 inches or more on which the tire is mounted. [Explanation of symbols]
[0127] 2,102...Bias tires (tires) 4. Tread surface 6...Tread 8. Sidewall 10, 10a, 10b...bead 12, 104... Code reinforcement 14. Tag components 16...Groove 18, 30, 32... rugs 20...bottom 40, 106...layers 42, 108...layer structure 44, 110... Reinforcement cord 48, 114... Carcass 50... belt 52, 54, 56, 116... Carcass ply 58, 118...Price main body 60, 120, 122, 124... Folded section 62, 126... Carcass Code 64... Belt ply 66... Belt cord 68... Electronic components 70... Protective body 76...RFID tags 78...Center Section 80... Side section
Claims
1. A tire comprising a pair of beads, a cord reinforcement body including reinforcing cords that spans between the pair of beads, a tread located radially outward from the cord reinforcement body, a pair of sidewalls located axially outward from the cord reinforcement body, and a tag member including electronic components, The tread comprises a plurality of lugs separated by grooves and arranged in the circumferential direction, The ratio of the lug height of each lug to the minimum thickness of the portion of the tire including the sidewall is 3.3 or more. The cord reinforcement comprises a carcass spanning between a pair of beads, or the cord reinforcement comprises the carcass and a belt positioned radially between the carcass and the tread. The carcass comprises at least one carcass ply, The carcass ply includes a carcass cord as the reinforcing cord, and the carcass cord is inclined with respect to the equatorial plane. The belt comprises at least one belt ply, The belt ply includes a belt cord as the reinforcing cord, and the belt cord is inclined with respect to the tire's equatorial plane. The cord reinforcement body has a layered structure consisting of at least two layers arranged radially on the radially inner side of the tread, The layer structure is composed of the carcass, or the carcass and the belt, The tag member is embedded inside the tread at the bottom of the groove. The tag member is positioned such that the longitudinal direction of the electronic component extends from the tire equatorial plane toward the edge of the tread. Bias tires.
2. The cord reinforcement is composed of the carcass and the belt, The belt ply is the outermost layer in the radial direction of the layer structure, The electronic component is positioned away from the end of the belt ply. The bias tire according to claim 1.
3. The cord reinforcement is composed of the carcass, The carcass ply comprises a ply body that spans between a pair of beads, namely the first bead and the second bead; a first folded portion connected to one end of the ply body and folded back by the first bead; and a second folded portion connected to the other end of the ply body and folded back by the second bead. The end of the first folded portion is laminated to the ply body on the second bead side beyond the tire's equatorial plane. The end of the second folded portion is stacked with the first folded portion on the first bead side that has crossed the tire's equatorial plane. The second folded portion is the outermost layer in the radial direction of the layer structure, The electronic component is positioned away from the end of the second folded portion. The bias tire according to claim 1.
4. The angle that the longitudinal direction of the electronic component makes with respect to the tire's equatorial plane is between 70 degrees and 110 degrees. A bias tire according to any one of claims 1 to 3.
5. The reinforcing cord included in the outermost layer in the radial direction of the aforementioned layer structure is an organic fiber cord. A bias tire according to any one of claims 1 to 3.
6. The tread comprises a center portion and side portions located axially outward from the center portion. At the bottom of the groove, the side portion is thicker than the center portion. The tag member is embedded inside the side portion. A bias tire according to any one of claims 1 to 3.
7. The ratio WE / WT of the axial distance WE from the tire equatorial plane to the boundary between the center portion and the side portion to the axial distance WT from the tire equatorial plane to the edge of the tread is 20% or more and 30% or less. The bias tire according to claim 6.
8. These are tires for agricultural machinery. A bias tire according to any one of claims 1 to 3.
9. It is mounted on the rear wheel of the aforementioned agricultural machine, The rim diameter of the rim on which the aforementioned tire is mounted is 20 inches or larger. The bias tire according to claim 8.