Tire and manufacturing method of the same

Abstract

To provide a tire which enables improvement of durability of a conductive member when the conductive member used for signal communication and power supply of an electronic device is installed on an inner surface rubber layer, and to provide a manufacturing method of the tire.SOLUTION: A tire includes: an inner surface rubber layer 10 forming a tire inner surface; and a conductive member 20 disposed on the inner surface rubber layer 10. The conductive member 20 is formed of a knitted fabric at least partially formed of a conductive yarn 23 and having elasticity and includes: an adhesion area A1 adhered to the inner surface rubber layer 10; and a non-adhesion area A2 which is not adhered to the inner surface rubber layer 10. At least a part of the conductive yarn 23 is included in the non-adhesion area A2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a tire having an inner surface rubber layer provided with a conductive member used for signal communication and power supply of electronic devices, and a manufacturing method thereof, and more particularly to a tire that makes it possible to improve the durability of the conductive member, and a manufacturing method thereof. [Background technology]

[0002] Conventionally, in a pneumatic tire, an electronic device is installed on the inner surface of the tire, and a conductive member is electrically connected to the electronic device, and communication and power supply are performed via the conductive member. As such a conductive member, a conductive wiring such as a metal wire is provided on the inner surface of the tire (for example, see Patent Documents 1 to 5).

[0003] However, tires deform during operation, and if excessive tension is applied to the wiring due to tire deformation, the wiring may break. Such a breakage can impair the functionality of the electronic device. Furthermore, repairing the wiring installed on the inner surface of the tire requires removing the tire from the rim. Therefore, the wiring of electronic devices must be highly durable.

[0004] In view of this situation, it has been proposed to reduce the tension applied to the conductive yarn by forming a conductive member from a knitted fabric containing conductive yarn and imparting stretchability to the conductive member (see, for example, Patent Document 6). However, even with this structure, the conductive yarn may break, and further improvement is required. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2007-537090 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-203829 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-217953 [Patent Document 4] Japanese Patent Application Laid-Open No. 2015-205528 [Patent Document 5] Japanese Patent Application Publication No. 2019-77296 [Patent Document 6] Patent No. 7173141 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a tire and a manufacturing method thereof that make it possible to improve the durability of a conductive member used in signal communication and power supply of electronic devices when the conductive member is installed on the inner surface rubber layer. [Means for solving the problem]

[0007] In order to achieve the above object, the tire of the present invention includes an inner surface rubber layer that forms an inner surface of the tire, and a conductive member disposed on the inner surface rubber layer, The conductive member is made of an elastic knitted fabric, at least a portion of which is made of conductive yarn, and has an adhesive region that is adhered to the inner surface rubber layer and a non-adhesive region that is not adhered to the inner surface rubber layer, and at least a portion of the conductive yarn is included in the non-adhesive region.

[0008] Further, a tire manufacturing method of the present invention is a method for manufacturing the above-mentioned tire, a step of molding an unvulcanized tire having the inner surface rubber layer; a step of attaching the conductive member to the inner surface rubber layer while inserting a film layer between a portion of the conductive member and the inner surface rubber layer; The tire is characterized in that it includes a step of vulcanizing the unvulcanized tire together with the conductive member and the film layer, forming the non-adhesive region at a portion of the conductive member that contacts the film layer, and forming the adhesive region at a portion of the conductive member that is separated from the film layer. [Effects of the Invention]

[0009] In the present invention, the conductive member is a stretchable knitted fabric at least partially composed of conductive yarns, so that even if the conductive member stretches due to tire deformation, the tension applied to the conductive yarns constituting the knitted fabric is reduced, thereby preventing breakage of the conductive yarns. Moreover, the conductive member has a bonded region that is bonded to the inner surface rubber layer and a non-bonded region that is not bonded to the inner surface rubber layer, and at least a portion of the conductive yarns are included in the non-bonded region. Therefore, by arranging the non-bonded region in a region where tire deformation is relatively large, the tension applied to the conductive yarns can be further reduced. This improves the durability of the conductive member.

[0010] In the present invention, it is preferable that at least a part of the knitted fabric is embedded in the inner surface rubber layer in the bonding region. That is, it is preferable that the conductive member is bonded to the inner surface rubber layer by embedding at least a part of the knitted fabric in the inner surface rubber layer. In this case, the conductive member can be mechanically fixed to the inner surface rubber layer without using an adhesive, which has the advantages of high fixing strength and low manufacturing costs.

[0011] In the present invention, it is preferred that the conductive portions made of conductive threads are formed along the longitudinal direction of the conductive member, the non-adhesive regions are formed so as to encompass the conductive-part-arrangement regions in the width direction of the conductive member, and the total length of the portions of the non-adhesive regions encompassing the conductive-part-arrangement regions is 30% or more of the length of the conductive member. By having the total length of the portions of the non-adhesive regions encompassing the conductive-part-arrangement regions be 30% or more of the length of the conductive member, the conductive portions made of conductive threads can move freely to a certain extent, thereby alleviating the tension applied to the conductive threads as the tire deforms and effectively improving the durability of the conductive member.

[0012] When the non-bonded region is formed so as to encompass, in the width direction of the conductive member, the conductive-part-arrangement region in which the conductive parts made of conductive threads are arranged, the width of the non-bonded region is preferably 1.2 to 4.5 times the width of the conductive-part-arrangement region, which allows the conductive parts made of conductive threads to move freely to a certain extent, thereby alleviating the tension applied to the conductive threads as the tire deforms and effectively improving the durability of the conductive member.

[0013] In the present invention, it is preferable that the conductive portion made of the conductive thread is formed along the longitudinal direction of the conductive member, and the non-adhesive region is formed in a portion of the longitudinal direction of the conductive member across the entire width of the conductive member. By forming the non-adhesive region in this manner in a portion of the longitudinal direction of the conductive member across the entire width of the conductive member, it is possible to alleviate the tension applied to the conductive thread due to tire deformation, and effectively improve the durability of the conductive member.

[0014] When the non-adhesive region is formed over the entire width of the conductive member in a portion of the longitudinal direction of the conductive member, the length Lf of the portion where the non-adhesive region is formed over the entire width of the conductive member is preferably 15% or more of the length of the conductive member, and at least a portion of the belt-adjacent region defined between a perpendicular line drawn from an end of the belt layer embedded in the tread portion to the tire inner surface and a position spaced from the perpendicular line along the tire inner surface toward the bead portion by a length equivalent to 0.12 times the tire cross-sectional height preferably overlaps with the portion having the length Lf of the non-adhesive region. Since the belt-adjacent region is the location where bending deformation of the tire inner surface is greatest, by arranging the conductive member so that at least a portion of the belt-adjacent region overlaps with the portion having the length Lf of the non-adhesive region, the tension applied to the conductive yarn due to tire deformation can be alleviated, and the durability of the conductive member can be effectively improved.

[0015] It is preferable that the entire portion of the non-adhesive region having length Lf be located radially outward of the position where the tire inner surface is at its widest in the tire width direction. Because the change in curvature when the tire flexes is large near the position where the tire inner surface is at its widest in the tire width direction, if the portion of the non-adhesive region having length Lf is located across that position, the conductive member will move more than necessary, potentially reducing the durability of the conductive member. In contrast, by locating the entire portion of the non-adhesive region having length Lf radially outward of the position where the tire inner surface is at its widest in the tire width direction, the durability of the conductive member can be effectively improved.

[0016] Where T is the average value of the tire thickness Ts at the bead portion side end of the belt-adjacent region and the tire thickness Tb at the belt layer side end of the belt-adjacent region, the overlap length Lfx of the portion having the non-adhesive region length Lf and the belt-adjacent region preferably satisfies the relationship 0.5≦Lfx / T≦3.2, which can effectively improve the durability of the conductive member.

[0017] It is preferable that the length Lf of the portion where the non-adhesive region is formed across the entire width of the conductive member satisfies the relationship 0.02≦Lf / Sh≦0.15 with respect to the tire cross-sectional height Sh, thereby effectively improving the durability of the conductive member.

[0018] It is preferable that the length Lf of the portion of the conductive member where the non-adhesive region is formed across the entire width thereof and the maximum width Wo of the conductive member in the portion having the non-adhesive region length Lf satisfy the relationship 0.8≦Lf / Wo≦6.5, which can effectively improve the durability of the conductive member.

[0019] In the present invention, it is preferable that a film layer be interposed between the conductive member and the inner surface rubber layer in the non-adhesive region, and that the film layer have a lower coefficient of friction than the inner surface rubber layer. By interposing a film layer with a low coefficient of friction between the conductive member and the inner surface rubber layer, breakage of the conductive threads due to friction can be prevented, and the durability of the conductive member can be improved.

[0020] In the present invention, it is preferable that at least a part of the conductive member is arranged in a flex zone defined between a perpendicular line extending from an end of a belt layer embedded in the tread portion to the tire inner surface and a perpendicular line extending from an outer diameter side end of a bead core embedded in the bead portion to the tire inner surface. In the present invention, the tension applied to the conductive yarn due to tire deformation can be alleviated, and therefore a significant effect can be exhibited when at least a part of the conductive member is arranged in a flex zone where deformation of the tire inner surface is relatively large.

[0021] When the conductive member is arranged across the flex zone, it is preferable that the conductive member have a terminal electrically connected to the conductive yarn outside the flex zone. Since the terminal electrically connected to the conductive yarn is more susceptible to breakage due to tire deformation than other parts, arranging the terminal outside the flex zone can increase the durability of the conductive member.

[0022] Furthermore, according to the tire manufacturing method of the present invention, the above-mentioned tire can be manufactured and durability of the conductive member can be improved by including the steps of: molding an unvulcanized tire having the inner surface rubber layer; attaching the conductive member to the inner surface rubber layer while inserting a film layer between a portion of the conductive member and the inner surface rubber layer; and vulcanizing the unvulcanized tire together with the conductive member and the film layer, forming the non-adhesive region at a portion of the conductive member that abuts against the film layer, and forming the adhesive region at a portion of the conductive member that is separate from the film layer. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a meridian half cross-sectional view showing a pneumatic tire according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing an example of a conductive member used in the present invention. [Figure 3] FIG. 10 is a perspective view showing a modified example of the conductive member used in the present invention. [Figure 4]1 is a plan view showing a knitted fabric of a conductive member used in the present invention. FIG. [Figure 5] 10(a) to 10(c) are perspective views showing modified examples of the conductive member used in the present invention. [Figure 6] 10(a) and 10(b) are perspective views showing modified examples of the conductive member used in the present invention. [Figure 7] 10(a) and 10(b) are perspective views showing modified examples of the conductive member used in the present invention. [Figure 8] 8A and 8B show a modified example of the conductive member used in the present invention, in which (a) is a perspective view and (b) is a cross-sectional view taken along line VIII-VIII. [Figure 9] 9A and 9B show a modified example of the conductive member used in the present invention, in which (a) is a perspective view and (b) is a cross-sectional view taken along line IX-IX. [Figure 10] 1 is a meridian half cross-sectional view showing an example of the arrangement of electronic devices in a pneumatic tire. [Figure 11] FIG. 1 is a perspective view showing a connection structure between an electronic device and a conductive member. [Figure 12] FIG. 10 is a perspective cross-sectional view showing another example of the arrangement of electronic devices in a pneumatic tire. [Figure 13] FIG. 10 is a perspective cross-sectional view showing another example of the arrangement of electronic devices in a pneumatic tire. [Figure 14] FIG. 10 is a perspective cross-sectional view showing another example of the arrangement of electronic devices in a pneumatic tire. DETAILED DESCRIPTION OF THE INVENTION

[0024] The configuration of the present invention will be described in detail below with reference to the accompanying drawings. Fig. 1 shows a pneumatic tire according to an embodiment of the present invention, and Figs. 2 to 4 show conductive members used in the present invention. In Fig. 1, CL is the tire center line.

[0025] 1, the pneumatic tire of this embodiment includes a tread portion 1 extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions 2, 2 arranged on both sides of the tread portion 1, and a pair of bead portions 3, 3 arranged radially inward of the sidewall portions 2. This pneumatic tire has a substantially symmetrical structure on both sides of the tire center line CL, but may also have an asymmetrical structure.

[0026] A carcass layer 4 is mounted between a pair of bead portions 3, 3. This carcass layer 4 includes a plurality of carcass cords extending in the tire radial direction, and is folded back from the inside to the outside of the tire around a bead core 5 disposed in each bead portion 3. Organic fiber cords such as polyester fiber cords are preferably used as the carcass cords of the carcass layer 4. A bead filler 6 made of a rubber composition and having a triangular cross section is disposed on the outer periphery of the bead core 5.

[0027] Meanwhile, multiple belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. These belt layers 7 include multiple belt cords that are inclined with respect to the tire circumferential direction, and are arranged so that the belt cords cross each other between the layers. In the belt layers 7, the inclination angle of the belt cords with respect to the tire circumferential direction is set to a range of 10° to 40°, for example. Steel cords are preferably used as the belt cords 7 of the belt layers 7. In the tread portion 1, multiple main grooves 11 extending in the tire circumferential direction and multiple lug grooves 12 extending in the tire width direction are formed. In the tread portion 1, grooves and sipes other than the main grooves 11 and lug grooves 12 can be provided as needed.

[0028] A belt cover layer 8 is arranged on the outer circumferential side of the belt layer 7, with the aim of improving high-speed durability, and is made up of reinforcing cords arranged at an angle of, for example, 5° or less with respect to the tire circumferential direction. The belt cover layer 8 may be a full cover layer that covers the entire width of the belt layer 7, or a pair of edge cover layers that locally cover both ends of the belt layer 7 in the tire width direction, either alone or in combination. The belt cover layer 8 may be formed, for example, by spirally winding a strip material in the tire circumferential direction, in which at least one reinforcing cord is aligned and covered with coating rubber.

[0029] The tire internal structure described above shows a typical example of a pneumatic tire, but is not limited to this. An inner surface rubber layer (inner liner layer) 10 that constitutes the tire inner surface S is disposed inside the carcass layer 4. The inner surface rubber layer 10 is an air permeation prevention layer and is made of a rubber composition mainly containing butyl rubber.

[0030] In the above-described pneumatic tire, as shown in FIG. 1, a strip-shaped conductive member 20 is disposed on the inner surface rubber layer 10 so as to extend in the tire radial direction. The conductive member 20 is electrically connected to an electronic device (not shown) and is used for signal communication and power supply for the electronic device. The electronic device is a device that operates using electrical energy, and may be composed of, for example, a power generation element, sensors that measure physical quantities such as pressure, temperature, acceleration, electric field, magnetic field, potential, electric resistance, and gas concentration, actuators such as motors and pumps, communication modules, wireless tags, receiving or transmitting antennas, secondary batteries, coils for contactless power supply, electronic circuit boards, etc.

[0031] As shown in FIGS. 2 to 4 , the conductive member 20 is made of a stretchable knitted fabric, at least a portion of which is made of conductive yarns 23. More specifically, the conductive member 20 is a knitted fabric formed by knitting conductive yarns 23 and non-conductive yarns 24. Conductive portions 21 made of the conductive yarns 23 and non-conductive portions 22 made of the non-conductive yarns 24 extend along the longitudinal direction of the conductive member 20, and these conductive portions 21 and non-conductive portions 22 are alternately arranged in the width direction of the conductive member 20. Since each conductive portion 23 includes conductive yarns 23 that are continuous along the longitudinal direction of the conductive member 20, each conductive portion 21 functions as a conductive path in the longitudinal direction of the conductive member 20. In addition, to ensure insulation between adjacent conductive portions 21, 21, it is preferable that the width of the non-conductive portions 22 located between adjacent conductive portions 21, 21 be 0.5 mm or more. The knitting method of the knitted fabric of the conductive member 20 is not particularly limited, as long as the conductive yarns 23 are continuous and the knitted fabric is stretchable. A knitted fabric having elasticity means that the elongation at break from the unstretched state is 50% or more. It is preferable that the elongation at break of the knitted fabric is 100% or more.

[0032] The conductive thread 23 is preferably a metal wire with an insulating coating, particularly a copper wire with an insulating coating. The insulating coating can prevent unintended short circuits in the electrical wiring formed by the conductive member 20. Furthermore, if the insulating coating melts when heat is applied, the conductive member 20 can be electrically connected to an electronic device by soldering. Resin materials such as polyurethane, polyester, polyvinyl formal, polyethylene, polyvinyl chloride, polyamide, polyamideimide, polyesterimide, and polyimide are preferred as insulating coatings.

[0033] The conductive yarn 23 may be formed from a single metal wire (monofilament), but is preferably formed from a bundle of multiple metal wires (multifilament). The diameter of the metal wire, including the insulating coating, is preferably in the range of 10 μm to 100 μm, more preferably 20 μm to 80 μm. A single conductive yarn 23 may be formed from a bundle of 3 to 12 metal wires. For example, a conductive yarn 23 formed from a bundle of seven metal wires with a diameter of 30 μm is exemplified. The non-conductive yarn 24 may be formed from a yarn made from synthetic fibers such as polyester fiber or aramid fiber. The non-conductive yarn 24 may be formed from a bundle of multiple fibers. In this case, it is preferable to use a yarn formed from a bundle of a larger number of fibers that are thinner than the metal wires of the conductive yarn 23. This ensures the flexibility of the knitted fabric even when the conductive yarn 23 is knitted.

[0034] The conductive member 20 has an adhesive region A1 that is adhered to the inner surface rubber layer 10 and a non-adhesive region A2 that is not adhered to the inner surface rubber layer 10, and is configured so that at least a portion of the conductive threads 23 is included in the non-adhesive region A2. In the example of FIG. 2, the adhesive region A1 is arranged at both longitudinal ends of the conductive member 20, and the non-adhesive region A2 is arranged in the longitudinal center of the conductive member 20. In the example of FIG. 3, the adhesive region A1 is arranged at both widthwise ends of the conductive member 20, and the non-adhesive region A2 is arranged in the widthwise center of the conductive member 20. In the adhesive region A1, the conductive member 20 may be adhered to the inner surface rubber layer 10 with an adhesive, or the conductive member 20 may be mechanically engaged with the inner surface rubber layer 10.

[0035] In the tire described above, the conductive member 20 is a stretchable knitted fabric at least a portion of which is made up of conductive yarns 23. This reduces the tension applied to the conductive yarns 23 that make up the knitted fabric even when the conductive member 23 stretches due to tire deformation, thereby preventing breakage of the conductive yarns 23. Furthermore, the conductive member 20 has a bonded region A1 that is bonded to the inner surface rubber layer 10 and a non-bonded region A2 that is not bonded to the inner surface rubber layer 10, and at least a portion of the conductive yarns 23 is included in the non-bonded region A2. Therefore, by arranging the non-bonded region A2 in a portion of the tire where deformation is relatively large, the tension applied to the conductive yarns 23 can be further reduced. This improves the durability of the conductive member 20.

[0036] In the bonding region A1, the conductive member 20 is mechanically engaged with the inner surface rubber layer 10, so that at least a portion of the knitted fabric of the conductive member 20 is preferably embedded in the inner surface rubber layer 10. That is, it is preferable that some or all of the conductive yarns 23 and non-conductive yarns 24 that make up the knitted fabric of the conductive member 20 are embedded in the inner surface rubber layer 10. In this case, the conductive member 20 can be mechanically fixed to the inner surface rubber layer 10 without using an adhesive, which increases the fixing strength between the conductive member 20 and the inner surface rubber layer 10 and also reduces manufacturing costs.

[0037] In the above tire, as shown in FIGS. 5(a) to 5(c), a conductive portion 21 made of a conductive yarn 23 is formed along the longitudinal direction of the conductive member 20, and a non-adhesive region A2 is formed so as to include a conductive portion arrangement region C where the conductive portion 21 is disposed in the width direction of the conductive member 20. In this case, it is preferable that the total length Lc of the portion of the non-adhesive region A2 that includes the conductive portion arrangement region C is 30% or more of the length L of the conductive member 20. Here, the conductive portion arrangement region C is a region that includes all the conductive portions 21 included in the conductive member 20. In FIG. 5(a), Lc = L. In FIG. 5(b), Lc < L. In FIG. 5(c), Lc = Lc1 + Lc2, and Lc < L. Since the total length Lc of the portion of the non-adhesive region A2 that includes the conductive portion arrangement region C is 30% or more of the length L of the conductive member 20, the conductive portion 21 made of the conductive yarn 23 can move freely to some extent. Thus, the tension applied to the conductive yarn 23 due to the deformation of the tire can be relaxed, and the durability of the conductive member 20 can be effectively improved.

[0038] Here, if the total length Lc of the portion of the non-adhesive region A2 that includes the conductive portion arrangement region C is less than 30% of the length L of the conductive member 20, the conductive yarn 23 is likely to break. In particular, it is preferable that the total length Lc of the portion of the non-adhesive region A2 that includes the conductive portion arrangement region C is 40% or more, more preferably 50% or more, of the length L of the conductive member 20. In this case, it is preferable that the adhesive region A1 exists on at least one side in the width direction of the conductive member 20 over the entire length of the conductive member 20. [[ID=⑤]] [[ID=⑥]]

[0039] [[ID=⑦]] [[ID=⑧]]As shown in FIGS. 6(a) and 6(b), when a non-adhesive region A2 is formed so as to include a conductive portion arrangement region C where the conductive portion 21 made of the conductive yarn 23 is disposed in the width direction of the conductive member 20, it is preferable that the width Wf of the non-adhesive region A2 is 1.2 to 4.5 times the width Wc of the conductive portion arrangement region C. Thereby, the conductive portion 21 made of the conductive yarn 23 can move freely to some extent. Thus, the tension applied to the conductive yarn 23 due to the deformation of the tire can be relaxed, and the durability of the conductive member 20 can be effectively improved. [[ID=⑨]] [[ID=⑩]]

[0040] [[ID=⑪]] Here, if the width Wf of the non-adhesive region A2 is less than 1.2 times the width Wc of the conductive portion-arrangement region C, the conductive threads 23 will be more likely to break, and conversely, if it is more than 4.5 times, the non-conductive portion 24 made of the non-conductive threads 22 will be more likely to be damaged. In particular, the width Wf of the non-adhesive region A2 should be 1.3 to 4.2 times, and more preferably 1.4 to 4.0 times, the width Wc of the conductive portion-arrangement region C. In either case, it is preferable that the non-adhesive region A2 exists on both sides of the conductive portion 21 made of the conductive threads 23 over an area that is 0.1 times or more the width Wc of the conductive portion-arrangement region C.

[0041] 7(a)-(b), in the tire described above, when the conductive portion 21 made of the conductive thread 23 is formed along the longitudinal direction of the conductive member 20, it is preferable that the non-bonded region A2 is formed over the entire width of the conductive member 20 in a portion of the longitudinal direction of the conductive member 20. By forming the non-bonded region A2 over the entire width of the conductive member 20 in a portion of the longitudinal direction of the conductive member 20 in this manner, the tension applied to the conductive thread 23 due to deformation of the tire can be alleviated, and the durability of the conductive member 20 can be effectively improved.

[0042] When the non-adhesive region A2 is formed over the entire width direction of the conductive member 20 in a portion of the longitudinal direction of the conductive member 20, it is preferable that the length Lf of the portion where the non-adhesive region A2 is formed over the entire width direction of the conductive member 20 is 15% or more of the length L of the conductive member 20. As shown in FIG. 1 , when a belt-adjacent region Bx is defined between a perpendicular line drawn from an end of the belt layer 7 embedded in the tread portion 1 to the tire inner surface S and a position spaced from the perpendicular line along the tire inner surface S toward the bead portion 3 by a length equivalent to 0.12 times the tire cross-sectional height Sh, it is preferable that at least a portion of the belt-adjacent region Bx overlaps with the portion having the length Lf of the non-adhesive region A2. Since the belt-adjacent region Bx is the location where bending deformation of the tire inner surface S is greatest, by arranging the conductive member 20 so that at least a portion of the belt-adjacent region Bx overlaps with the portion having the length Lf of the non-adhesive region A2, it is possible to alleviate the tension applied to the conductive yarn 23 due to tire deformation and effectively improve the durability of the conductive member 20. In particular, it is desirable that the entire belt-adjacent region Bx be included within the length Lf of the portion where the non-adhesive region A2 is formed across the entire width of the conductive member 20. The tire cross-sectional height Sh is half the distance between the tire outer diameter and the rim diameter, and is measured with the tire mounted on a specified rim, the specified internal pressure applied, and in an unloaded state. The specified rim refers to the "applicable rim" specified by JATMA, the "design rim" specified by TRA, or the "measuring rim" specified by ETRTO. The specified internal pressure refers to the "maximum inflation pressure" specified by JATMA, the maximum value of the "tire load limits at various cold inflation pressures" specified by TRA, or the "inflation pressures" specified by ETRTO.

[0043] In FIG. 1 , when the position where the tire inner surface S is widest in the tire width direction is defined as the maximum width position Pmax, it is preferable that the entire portion of the non-bonded region A2 having the length Lf be located radially outward of the maximum width position Pmax. Because the change in curvature when the tire flexes is large near the maximum width position Pmax, if the portion of the non-bonded region A2 having the length Lf is located across the maximum width position Pmax, the conductive member 20 will move more than necessary, which may reduce the durability of the conductive member 20. In contrast, by locating the entire portion of the non-bonded region A2 having the length Lf radially outward of the maximum width position Pmax, the durability of the conductive member 20 can be effectively improved. The position where the tire inner surface S is widest in the tire width direction is identified based on an image captured by CT scanning of the tire mounted on a standard rim, inflated to the standard internal pressure, and not in contact with the ground.

[0044] As shown in FIG. 1 , the tire thickness Ts at the end of the belt-adjacent region Bx on the bead portion 3 side and the tire thickness Tb at the end of the belt-adjacent region Bx on the belt layer 7 side are averaged together to form an average value T (T = (Ts + Tb) / 2). As shown in FIG. 7 , the overlap length Lfx between the portion having the length Lf of the non-adhesive region A2 and the belt-adjacent region Bx should satisfy the relationship 0.5≦Lfx / T≦3.2. This effectively improves the durability of the conductive member. If the overlap length Lfx is too short with respect to the average tire thickness T, the effect of the non-adhesive region A2 is reduced. Conversely, if it is too long, excessive movement of the conductive member 20 in response to tire deformation occurs, reducing the durability of the conductive member 20. The tire thicknesses Ts and Tb are each measured along the normal direction of the tire inner surface S and do not include the thickness of the conductive member 20.

[0045] The length Lf of the portion where the non-adhesive region A2 is formed across the entire width of the conductive member 20 preferably satisfies the relationship 0.02≦Lf / Sh≦0.15 with respect to the tire cross-sectional height Sh. This effectively improves the durability of the conductive member 20. If the length Lf is too short with respect to the tire cross-sectional height Sh, the effect of the non-adhesive region A2 decreases, and conversely, if it is too long, the conductive member 20 moves excessively in response to tire deformation, reducing the durability of the conductive member 20.

[0046] The length Lf of the portion of the conductive member 20 where the non-adhesive region A2 is formed across the entire width of the conductive member 20 and the maximum width Wo of the conductive member 20 at the portion having the length Lf of the non-adhesive region A2 preferably satisfy the relationship 0.8≦Lf / Wo≦6.5. This effectively improves the durability of the conductive member 20. If the length Lf is too short relative to the maximum width Wo of the conductive member 20, the effect of the non-adhesive region A2 is reduced. Conversely, if it is too long, the conductive member 20 moves excessively in response to tire deformation, reducing the durability of the conductive member 20. The maximum width Wo of the conductive member 20 per number of conductive portions 21 is preferably in the range of 1.0 mm to 3.5 mm. If the maximum width Wo of the conductive member 20 per number of conductive portions 21 is less than 1.0 mm, the conductive portions 21 or the spacing between them will be narrow, which may reduce the strength of the member or reduce the allowable current, potentially hindering stable power supply and signal communication. On the other hand, if the maximum width Wo of the conductive member 20 per installed conductive portion 21 is greater than 3.5 mm, the conductive member 20 will be larger than necessary, which will increase the movement of the conductive member 20 in the non-bonded region A2 and reduce the durability of the conductive member 20. The number of conductive portions 21 installed on a single conductive member 20 is preferably 2 to 5. If the installed number of conductive portions 21 is too small, the installation efficiency of the conductive member 20 throughout the tire will be poor, and conversely, if the installed number is too large, the width of the conductive member 20 will be too wide, which will likely result in a decrease in durability due to an increase in mass.

[0047] In the tire described above, it is preferable that a film layer 25 is interposed between the conductive member 20 and the inner surface rubber layer 10 in the non-adhesive region A2. In FIGS. 8(a) and 8(b), the film layer 25 is inserted between the conductive member 20 and the inner surface rubber layer 10 over the entire non-adhesive region A2, which is located in the longitudinal center of the conductive member 20. In FIGS. 9(a) and 9(b), the film layer 25 is inserted between the conductive member 20 and the inner surface rubber layer 10 over the entire non-adhesive region A2, which is located in the widthwise center of the conductive member 20. The film layer 25 has a lower coefficient of friction than the inner surface rubber layer 10. The coefficient of friction is measured in accordance with JIS-K7125 "Plastics - Films and Sheets - Test Method for Coefficient of Friction." By thus interposing the film layer 25, which has a low coefficient of friction, between the conductive member 20 and the inner surface rubber layer 10, breakage of the conductive threads 23 due to rubbing can be prevented, and the durability of the conductive member 20 can be improved.

[0048] Examples of materials for the film layer 25 include resin materials such as polyolefin, polyacetal, polyamide, polyester, polycarbonate, modified polyphenylene ether (PPE), polyphenylene sulfide (PPS), polyolefin ketone (POK), polyether ether ketone (PEEK), polysulfone (PSU), polyethersulfone (PES), polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polytetrafluoroethylene (PTFE), silicone resin, and epoxy resin, and thermoplastic elastomers (styrene-based, hydrogenated styrene-based, olefin-based, polyester-based, polyurethane-based, polyamide-based, and vinyl chloride-based).

[0049] In the above tire, as shown in Fig. 1, it is preferable that at least a part of the conductive member 20 is disposed in a flex zone Fx defined between a perpendicular line extending from an end of the belt layer 7 embedded in the tread portion 1 to the tire inner surface S and a perpendicular line extending from an outer diameter side end of the bead core 5 embedded in the bead portion 3 to the tire inner surface S. In the present invention, the tension applied to the conductive thread 23 due to tire deformation can be alleviated, and therefore a significant effect can be achieved when at least a part of the conductive member 20 is disposed in the flex zone Fx where deformation of the tire inner surface S is relatively large.

[0050] When the conductive member 20 is arranged so as to cross the flex zone FX, it is preferable that the conductive member 20 has a terminal 30 outside the flex zone Fx that is electrically connected to the conductive thread 23. In Fig. 1, the terminals 30 are provided at a portion of the conductive member 20 that is outer than the flex zone FX in the tire radial direction and at a portion of the conductive member 20 that is inner than the flex zone FX in the tire radial direction. Because the terminal 30 that is electrically connected to the conductive thread 23 is a portion that is prone to breakage due to tire deformation, arranging the terminal 30 outside the flex zone Fx can increase the durability of the conductive member 20.

[0051] Next, a method for manufacturing the above-mentioned pneumatic tire will be described. First, an unvulcanized tire is molded, which includes an inner surface rubber layer 10 in addition to the carcass layer 4, bead cores 5, bead fillers 6, belt layers 7, and belt cover layers 8. Then, in the unvulcanized tire, a conductive member 20 is attached to the inner surface rubber layer 10, and a film layer 25 is inserted between a portion of the conductive member 20 and the inner surface rubber layer 10. The conductive member 20 and the film layer 25 can also be attached as a pre-pressed assembly. Next, the unvulcanized tire is vulcanized together with the conductive member 20 and the film layer 25, thereby forming a non-bonded region A2 in the portion of the conductive member 20 that abuts against the film layer 25, and forming a bonded region A2 in the portion of the conductive member 20 that is not covered by the film layer 25. That is, by attaching the conductive member 20 and the film layer 25 to the inner surface rubber layer 10 before vulcanization, the conductive member 20 is in a non-adhered state in the areas where the film layer 25 is present, and is in an adhered state by being embedded in the inner surface rubber layer 10 in the areas where the film layer 25 is not present. This allows for efficient production of tires equipped with the conductive member 20, and furthermore, because the conductive member 20 is mechanically engaged with the inner surface rubber layer 10, the durability of the conductive member 20 can be increased.

[0052] The tire manufacturing method described above is a preferred method, but is not limited to this. For example, it is also possible to attach the conductive member 20 to the inner surface rubber layer 10 after vulcanizing the tire by a conventional method.

[0053] FIG. 10 shows an example of the arrangement of electronic devices in a pneumatic tire, and FIG. 11 shows a connection structure between the electronic device and a conductive member. In FIG. 10, an electronic device 40 is installed on the tire inner surface S, and the electronic device 40 is located at a position on the tire center line CL. One end of a conductive member 20 arranged on the inner surface rubber layer 10 is electrically connected to the electronic device 40, and the other end extends toward the bead portion 3. As shown in FIG. 11, the electronic device 40 includes a substrate 41, a pair of terminals 42 mounted on the substrate 41, various electronic components 43 mounted on the substrate 41, and wiring 44 connecting the terminals 42 and the electronic components 43 to each other. The electronic device 40 is electrically connected to a pair of conductive portions 21 of the conductive member 20 via the pair of terminals 42. The distance between the pair of terminals 42 in the electronic device 40 is preferably equal to the distance between the pair of conductive portions 21 in the conductive member 20. In this case, the terminals 42 of the electronic device 40 and the conductive portions 21 of the conductive member 20 can be directly connected by soldering or the like without using any other electric wires.

[0054] 12 to 14 each show an example of the arrangement of an electronic device in a pneumatic tire. As shown in FIGS. 12 to 14, an electronic device 40 is installed on the tire inner surface S, and a conductive member 20 is arranged to extend from the electronic device 40 along the tire inner surface S. In FIG. 12, wide conductive members 20 are connected to both sides in the tire width direction of a large electronic device 40 that requires relatively large amounts of power, and each conductive member 20 is used as positive or negative wiring. In FIGS. 13 and 14, a conductive member 20 is connected to one side in the tire width direction of a small electronic device 40 that operates with relatively small amounts of power, and each conductive portion 21 of the conductive member 20 is used as positive or negative wiring. In FIG. 13, the conductive member 20 extends in the tire width direction, whereas in FIG. 14, the conductive member 20 extends in a direction oblique to the tire width direction. [Example]

[0055] The tire size was 245 / 40R19, and the tire was equipped with an inner surface rubber layer that constituted the inner surface of the tire, and a conductive member disposed on the inner surface rubber layer. The conductive member was made of a stretchable knitted fabric that included a conductive portion made of conductive yarn and a non-conductive portion made of non-conductive yarn, and tires of Comparative Example 1 and Examples 1 to 12 were manufactured with different adhesion states of the conductive member to the inner surface rubber layer.

[0056] The conductive member was adhered over the entire area in Comparative Example 1. In Examples 1 to 12, the conductive member had an adhered region adhered to the inner surface rubber layer and a non-adhesive region not adhered to the inner surface rubber layer, and at least a portion of the conductive thread was included in the non-adhesive region. In Examples 1 to 12, the bonding form of the conductive member, the ratio (Lc / L) of the length L of the conductive member to the total length Lc of the portion of the non-bonded region including the conductive-portion-arrangement region, the ratio (Wf / Wc) of the width Wf of the non-bonded region to the width Wc of the conductive-portion-arrangement region, the ratio (Lf / L) of the length Lf of the portion where the non-bonded region is formed over the entire width of the conductive member to the length L of the conductive member, the ratio (Lfx / T) of the overlap length Lfx of the portion having the non-bonded region length Lf with the belt-adjacent region to the average tire thickness T, the ratio (Lf / Sh) of the length Lf of the portion where the non-bonded region is formed over the entire width of the conductive member to the tire cross-sectional height Sh, the ratio (Lf / Wo) of the length Lf of the portion where the non-bonded region is formed over the entire width of the conductive member to the maximum width Wo of the conductive member, and the presence or absence of a film layer interposed between the conductive member and the inner surface rubber layer were set as shown in Table 1. In the bonded region, at least a portion of the knitted fabric of the conductive member was embedded in the inner surface rubber layer. The conductive member is positioned across the flex zone so that at least a portion of the belt-adjacent region overlaps with the non-adhesive region.

[0057] The durability of the conductive members of these test tires was evaluated by the following evaluation method, and the results are shown in Table 1.

[0058] Conductive material durability: Each test tire was mounted on a wheel with a rim size of 19x8J, the air pressure was set to 150 kPa, and the tire was mounted on a drum testing machine with a smooth steel drum surface and a diameter of 1707 mm. A 3000 km running test was conducted under conditions of a speed of 120 km / h and a load of 100% of the JATMA maximum load, while the ambient temperature was controlled at 38±3°C. After the running test, the electrical resistance of the entire conductive member (the resistance value measured between both ends of the conductive member with the ends of all conductive parts shorted together) was measured. The evaluation results were expressed as an index using the reciprocal of the measured value, with Comparative Example 1 being set at 100. A higher index value indicates better durability of the conductive member.

[0059] [Table 1]

[0060] As can be seen from Table 1, in comparison with Comparative Example 1, the durability of the conductive members of the tires of Examples 1 to 12 was improved.

[0061] The present disclosure includes the following inventions [1] to

[14] . Invention [1] is a tire having an inner surface rubber layer that constitutes the inner surface of the tire, and a conductive member disposed on the inner surface rubber layer, The tire is characterized in that the conductive member is made of a stretchable knitted fabric at least a portion of which is made of conductive yarn, and has an adhered region adhered to the inner surface rubber layer and a non-adhesive region not adhered to the inner surface rubber layer, and at least a portion of the conductive yarn is included in the non-adhesive region. Invention [2] is the tire according to invention [1], characterized in that in the adhesive region, at least a portion of the knitted fabric is embedded in the inner surface rubber layer. Invention [3] is a tire according to invention [1] or [2], characterized in that the conductive portion made of the conductive thread is formed along the longitudinal direction of the conductive member, the non-bonded region is formed so as to encompass the conductive portion arrangement region in which the conductive portion is arranged in the width direction of the conductive member, and the total length of the portion of the non-bonded region encompassing the conductive portion arrangement region is 30% or more of the length of the conductive member. Invention [4] is the tire according to invention [3], characterized in that the width of the non-adhesive region is 1.2 to 4.5 times the width of the conductive portion arrangement region. Invention [5] is a tire according to invention [1] or [2], characterized in that the conductive portion made of the conductive thread is formed along the longitudinal direction of the conductive member, and the non-adhesive region is formed over the entire width of the conductive member in a part of the longitudinal direction of the conductive member. Invention [6] is a method for manufacturing a conductive member having a non-adhesive region, the non-adhesive region having a length Lf of 15% or more of the length of the conductive member, the non-adhesive region being formed over the entire width direction of the conductive member, The tire according to invention [5] is characterized in that at least a part of the belt-adjacent region defined between a perpendicular line drawn from an end of a belt layer embedded in a tread portion to the tire inner surface and a position spaced apart from the perpendicular line along the tire inner surface toward the bead portion by a length equivalent to 0.12 times the tire cross-sectional height overlaps with a portion of the non-adhesive region having the length Lf. Invention [7] is the tire according to invention [6], characterized in that the entire portion of the non-adhesive region having the length Lf is positioned radially outward of the position where the inner surface of the tire is widest in the tire width direction. Invention [8] is the tire according to invention [6] or [7], characterized in that, where T is the average value of the tire thickness Ts at the bead portion side end of the belt-adjacent region and the tire thickness Tb at the belt layer side end of the belt-adjacent region, the overlap length Lfx of the portion of the non-adhesive region having the length Lf and the belt-adjacent region satisfies the relationship 0.5≦Lfx / T≦3.2. Invention [9] is a tire according to any one of inventions [6] to [8], characterized in that the length Lf of the portion where the non-adhesive region is formed across the entire width of the conductive member satisfies the relationship 0.02≦Lf / Sh≦0.15 with respect to the tire cross-sectional height Sh. Invention

[10] is a tire according to any one of inventions [6] to [9], characterized in that the length Lf of the portion where the non-adhesive region is formed across the entire width of the conductive member and the maximum width Wo of the conductive member in the portion where the non-adhesive region has the length Lf satisfy the relationship 0.8≦Lf / Wo≦6.5. Invention

[11] is a tire according to any one of inventions [1] to

[10] , characterized in that in the non-adhesive region, a film layer is interposed between the conductive member and the inner surface rubber layer, and the coefficient of friction of the film layer is lower than the coefficient of friction of the inner surface rubber layer. Invention

[12] is a tire according to any one of inventions [1] to

[11] , characterized in that at least a part of the conductive member is arranged in a flex zone defined between a perpendicular line extending from an end of a belt layer embedded in a tread portion to the tire inner surface and a perpendicular line extending from an outer diameter side end of a bead core embedded in a bead portion to the tire inner surface. Invention

[13] is a tire according to invention

[12] , characterized in that the conductive member is arranged across the flex zone and has a terminal outside the flex zone that is electrically connected to the conductive yarn. Invention

[14] is a method for producing a tire according to any one of Inventions [1] to

[13] , a step of molding an unvulcanized tire having the inner surface rubber layer; a step of attaching the conductive member to the inner surface rubber layer while inserting a film layer between a portion of the conductive member and the inner surface rubber layer; vulcanizing the unvulcanized tire together with the conductive member and the film layer, forming the non-adhesive region at a portion of the conductive member that contacts the film layer, and forming the adhesive region at a portion of the conductive member that is separated from the film layer. [Explanation of symbols]

[0062] 1 Tread section 2 Sidewall 3 Bead section 4 carcass layers 5 bead core 6 Bead filler 7 Belt Layer 8 Belt cover layer 10 Inner surface rubber layer 20 Conductive material 21 Conductive part 22 Non-conductive parts 23 Conductive thread 24 Non-conductive thread 25 film layers 30 terminals 40 Electronic Devices

Claims

1. A tire comprising an inner surface rubber layer that forms an inner surface of the tire, and a conductive member disposed on the inner surface rubber layer, the conductive member is made of a stretchable knitted fabric at least a portion of which is made of conductive yarn, and has an adhered region adhered to the inner surface rubber layer and a non-adhesive region not adhered to the inner surface rubber layer, and at least a portion of the conductive yarn is included in the non-adhesive region.

2. 2. The tire according to claim 1, wherein at least a portion of the knitted fabric is embedded in the inner surface rubber layer in the bonded region.

3. 2. The tire according to claim 1, wherein the conductive portion made of the conductive thread is formed along the longitudinal direction of the conductive member, the non-bonded region is formed so as to encompass, in the width direction of the conductive member, a conductive portion arrangement region in which the conductive portion is arranged, and the total length of the portion of the non-bonded region encompassing the conductive portion arrangement region is 30% or more of the length of the conductive member.

4. 4. The tire according to claim 3, wherein the width of the non-adhesive region is 1.2 to 4.5 times the width of the conductive portion arrangement region.

5. 2. The tire according to claim 1, wherein the conductive portion made of the conductive thread is formed along the longitudinal direction of the conductive member, and the non-adhesive region is formed over the entire width direction of the conductive member in a part of the longitudinal direction of the conductive member.

6. a length Lf of a portion where the non-adhesive region is formed over the entire width direction of the conductive member is 15% or more of the length of the conductive member; 6. The tire according to claim 5, wherein at least a part of a belt-adjacent region defined between a perpendicular line drawn from an end of a belt layer embedded in a tread portion to the tire inner surface and a position spaced apart from the perpendicular line along the tire inner surface toward a bead portion by a length equivalent to 0.12 times the tire cross-sectional height overlaps with a portion of the non-adhesive region having the length Lf.

7. 7. The tire according to claim 6, wherein the entire portion of the non-adhesive region having the length Lf is disposed radially outward of a position where the inner surface of the tire is widest in the tire width direction.

8. 8. The tire according to claim 7, wherein an overlap length Lfx between a portion of the non-adhesive region having the length Lf and the belt-adjacent region satisfies the relationship 0.5≦Lfx / T≦3.2, where T is an average value T of a tire thickness Ts at the bead portion side end of the belt-adjacent region and a tire thickness Tb at the belt layer side end of the belt-adjacent region.

9. 8. The tire according to claim 7, wherein a length Lf of a portion where the non-adhesive region is formed across the entire width direction of the conductive member satisfies the relationship 0.02≦Lf / Sh≦0.15 with respect to a tire cross-sectional height Sh.

10. 8. The tire according to claim 7, wherein a length Lf of a portion where the non-adhesive region is formed over the entire width direction of the conductive member and a maximum width Wo of the conductive member in the portion of the non-adhesive region having the length Lf satisfy the relationship 0.8≦Lf / Wo≦6.

5.

11. 2. The tire according to claim 1, wherein in the non-adhesive region, a film layer is interposed between the conductive member and the inner surface rubber layer, and the film layer has a lower friction coefficient than the inner surface rubber layer.

12. 2. The tire according to claim 1, wherein at least a portion of the conductive member is disposed in a flex zone defined between a perpendicular line extending from an end of a belt layer embedded in a tread portion to the tire inner surface and a perpendicular line extending from an outer diameter side end of a bead core embedded in a bead portion to the tire inner surface.

13. 13. The tire of claim 12, wherein the conductive member is disposed across the flex zone and has a terminal electrically connected to the conductive yarn outside the flex zone.

14. A method for manufacturing a tire according to any one of claims 1 to 13, a step of molding an unvulcanized tire having the inner surface rubber layer; a step of attaching the conductive member to the inner surface rubber layer while inserting a film layer between a part of the conductive member and the inner surface rubber layer; vulcanizing the unvulcanized tire together with the conductive member and the film layer, forming the non-adhesive region at a portion of the conductive member that abuts against the film layer, and forming the adhesive region at a portion of the conductive member that is separated from the film layer.

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