Pneumatic radial tires for passenger cars

Abstract

To provide a pneumatic radial tire for a passenger car making both durability and communication performance of a communication device compatible.SOLUTION: A pneumatic radial tire for a passenger car according to the present invention comprises a belt constituted of one or more belt layers, a tread and a communication device, where a cross sectional width SW of the tire and an outer diameter OD of the tire satisfy a predetermined relation. Belt cords constituting the belt layers are non-metal cords, and the communication device is provided in the tread.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a pneumatic radial tire for passenger cars. [Background technology]

[0002] Conventionally, there are known tires that are provided with a communication device on the inner surface or inside the tire, such as a sensor that detects the internal state of the pneumatic tire, such as the air pressure of the pneumatic tire, or an RF (radio frequency) tag that has a memory unit that can store the unique identification information of the pneumatic tire, etc. For example, the sensor as a communication device can determine the state of the tire while traveling, and various tire information obtained from the memory unit of the RF tag as a communication device can be used for maintenance services, etc.

[0003] For example, Patent Document 1 discloses a pneumatic tire in which an RF tag is sandwiched between carcass plies and the like. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-55450 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the tire described in Patent Document 1, the RF tag is in contact with the carcass ply, and the deformation of the carcass ply during tire rolling may affect the RF tag, which may impair the durability of the RF tag. In this way, the durability of the RF tag may be impaired by tire deformation or the like. Such a problem may occur not only with RF tags but also with communication devices in general that are provided in tires. On the other hand, it is possible to ensure durability by firmly covering the communication device with a protective member, but this would result in an increase in weight due to the protective member, and the protective member may also reduce communication performance, making it generally difficult to achieve both durability and communication performance of the communication device.

[0006] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a pneumatic radial tire for passenger cars which achieves both durability and communication performance of a communication device. [Means for solving the problem]

[0007] The gist and configuration of the present invention are as follows. (1) A pneumatic radial tire for passenger cars having a belt consisting of one or more belt layers, a tread, and a communication device, The tire has a section width SW of less than 165 (mm), and a ratio SW / OD of the section width SW to the outer diameter OD of the tire is 0.26 or less, The belt cord constituting the belt layer is a non-metallic cord, A pneumatic radial tire for passenger cars, characterized in that the communication device is provided in the tread.

[0008] (2) A pneumatic radial tire for passenger cars having a belt consisting of one or more belt layers, a tread, and a communication device, The tire has a cross-sectional width SW of less than 165 (mm), The tire section width SW (mm) and the outer diameter OD (mm) are expressed by the following relation: OD(mm)≧-0.0187×SW(mm) 2 +9.15×SW(mm)-380(mm) Fulfilling The belt cord constituting the belt layer is a non-metallic cord, A pneumatic radial tire for passenger cars, characterized in that the communication device is provided in the tread.

[0009] (3) A pneumatic radial tire for passenger cars according to (1) or (2) above, wherein the tread surface has one or two circumferential main grooves extending in the circumferential direction of the tire, or the tread surface has no circumferential main grooves.

[0010] (4) The pneumatic radial tire for passenger cars according to any one of (1) to (3) above, wherein the communication device is an RF tag. Effect of the Invention

[0011] According to the present invention, it is possible to provide a pneumatic radial tire for passenger vehicles that achieves both durability and communication performance of a communication device. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing the section width SW and outside diameter OD of a tire. [Diagram 2] 1 is a cross-sectional view in the tire width direction of a pneumatic radial tire for passenger cars according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0014] FIG. 1 is a schematic diagram showing the section width SW and outside diameter OD of a tire. A pneumatic radial tire for passenger cars (hereinafter, simply referred to as tire) according to one embodiment of the present invention has a tire section width SW of less than 165 (mm), and a ratio SW / OD of the tire section width SW to the outer diameter OD of 0.26 or less, forming a narrow width / large diameter shape. By making the tire section width SW narrower than the tire outer diameter OD, it is possible to reduce air resistance, and by making the tire outer diameter OD larger than the tire section width SW, it is possible to suppress deformation of the tread rubber near the tire's contact surface and reduce rolling resistance, thereby improving the fuel efficiency of the tire. The above SW / OD is preferably 0.25 or less, and more preferably 0.24 or less. The above ratio is preferably satisfied when the tire internal pressure is 200 kPa or more, more preferably when it is 220 kPa or more, and even more preferably when it is 280 kPa or more, since this allows for a reduction in rolling resistance. On the other hand, the above ratio is preferably satisfied when the tire internal pressure is 350 kPa or less, since this allows for an improvement in ride comfort. Here, the tire section width SW is preferably from 105 to 145 mm, and more preferably from 115 to 135 mm. Furthermore, the aspect ratio of the tire is more preferably 45 to 70, and even more preferably 45 to 65, when the section width SW and the outer diameter OD of the tire satisfy the above ratio. Specific tire sizes are not particularly limited, but examples include 105 / 50R16, 115 / 50R17, 125 / 55R20, 125 / 60R18, 125 / 65R19, 135 / 45R21, 135 / 55R20, 135 / 60R17, 135 / 60R18, 135 / 60R19, 135 / 65R19, 145 / 45R21, 145 / 5 5R20, 145 / 60R16, 145 / 60R17, 145 / 60R18, 145 / 60R19, 145 / 65R19, 155 / 45R18, 155 / 45R21, 155 / 55R18, 155 / 55R19, 155 / 55R21, 155 / 60R17, 155 / 65R18, 155 / 70R17, or 155 / 70R19.

[0015] Alternatively, the tire has a section width SW of less than 165 mm, and the section width SW (mm) and the outside diameter OD (mm) of the tire satisfy the following relationship: OD(mm)≧-0.0187×SW(mm) 2 +9.15×SW(mm)-380 and has a narrow width and large diameter. By satisfying the above relational expression, it is possible to reduce air resistance and rolling resistance, thereby improving the fuel efficiency of the tire. In the third aspect, the tire's section width SW and outer diameter OD satisfy the above-mentioned relational expressions, and the ratio SW / OD is preferably 0.26 or less, more preferably 0.25 or less, and even more preferably 0.24 or less, because this can further improve the fuel economy of the tire. The above-mentioned relationship and / or ratio is preferably satisfied when the tire internal pressure is 200 kPa or more, more preferably when the tire internal pressure is 220 kPa or more, and even more preferably when the tire internal pressure is 280 kPa or more, since it is possible to reduce rolling resistance. On the other hand, the above-mentioned relationship and / or ratio is preferably satisfied when the tire internal pressure is 350 kPa or less, since it is possible to improve ride comfort. Here, the tire section width SW is preferably from 105 to 145 mm, and more preferably from 115 to 135 mm. Further, the aspect ratio of the tire is more preferably 45 to 70, and even more preferably 45 to 65, when the section width SW and the outer diameter OD of the tire satisfy the above relational expression. Specific tire sizes are not particularly limited, but examples include 105 / 50R16, 115 / 50R17, 125 / 55R20, 125 / 60R18, 125 / 65R19, 135 / 45R21, 135 / 55R20, 135 / 60R17, 135 / 60R18, 135 / 60R19, 135 / 65R19, 145 / 45R21, 145 / 5 5R20, 145 / 60R16, 145 / 60R17, 145 / 60R18, 145 / 60R19, 145 / 65R19, 155 / 45R18, 155 / 45R21, 155 / 55R18, 155 / 55R19, 155 / 55R21, 155 / 60R17, 155 / 65R18, 155 / 70R17, or 155 / 70R19.

[0016] The tire of the present embodiment is a pneumatic radial tire for passenger cars, and is particularly suitable for use as a tire to be mounted on a vehicle for personal mobility.

[0017] Fig. 2 is a tire widthwise cross-sectional view of a pneumatic radial tire for passenger cars according to one embodiment of the present invention. Fig. 2 shows a tire widthwise cross-sectional view in a reference state in which the tire is mounted on a rim, inflated to a specified internal pressure, and unloaded. As shown in Fig. 2, the tire 1 has a carcass 3 made of radially arranged cord plies that span a toroidal shape between a pair of bead portions 2. The tire 1 also has a belt 4, which is made of two belt layers 4a and 4b in the illustrated example, and a tread 5, in that order, on the tire radial outer side of the carcass 3.

[0018] The above "rim" refers to the standard rim (Measuring Rim in the ETRTO Standards Manual, Design Rim in the TRA Year Book) for the applicable size that is described or will be described in the future in the industrial standards valid in the region where the tire is produced and used, such as the JATMA Year Book of the Japan Automobile Tire Manufacturers Association (JATMA) in Japan, the Standards Manual of the European Tyre and Rim Technical Organisation (ETRTO) in Europe, and the Year Book of the Tire and Rim Association, Inc. (TRA) in the United States (i.e., the "rim portion" of the above "wheel" includes not only current sizes, but also sizes that may be included in the above industrial standards in the future. An example of "sizes that will be described in the future" is the size described as "FUTURE DEVELOPMENTS" in the 2013 edition of the ETRTO.), however, in the case of a size not described in the above industrial standards, it refers to a rim with a width that corresponds to the bead width of the tire. In addition, "prescribed internal pressure" refers to the air pressure (maximum air pressure) that corresponds to the maximum load capacity of a single wheel for the applicable size and ply rating as stated in the above JATMA etc., and in the case of sizes not stated in the above industry standards, "prescribed internal pressure" refers to the air pressure (maximum air pressure) that corresponds to the maximum load capacity specified for each vehicle on which the tire is fitted. The "maximum load" described below means a load corresponding to the maximum load capacity.

[0019] In this example, a bead core 2a is embedded in each of the pair of bead portions 2. In the present invention, the cross-sectional shape and material of the bead core 2a are not particularly limited, and the bead core 2a may have a configuration that is normally used in pneumatic radial tires for passenger cars. In the present invention, the bead core 2a may be divided into a plurality of small bead cores. Alternatively, the present invention may have a configuration that does not include the bead core 2a.

[0020] The tire 1 in the illustrated example has a bead filler 2b with a substantially triangular cross section on the tire radial direction outer side of the bead core 2a. The cross-sectional shape of the bead filler 2b is not limited to this example, and the material is not particularly limited. Alternatively, the tire can be made lighter by not having the bead filler 2b.

[0021] In this embodiment, the tire 1 may have a structure having a rim guard. In this embodiment, the bead portion 2 may further be provided with additional members such as a rubber layer or a cord layer for the purpose of reinforcement, etc. Such additional members may be provided at various positions relative to the carcass 3 and the bead filler 2b.

[0022] In the example shown in FIG. 2, the carcass 3 is made of one carcass ply. On the other hand, in the present invention, the number of carcass plies is not particularly limited, and may be two or more. Also, in the example shown in FIG. 2, the carcass 3 has a carcass main body 3a that spans a pair of bead portions 2 in a toroidal shape, and a folded-up portion 3b that is folded back from the carcass main body 3a around the bead core 2a. On the other hand, in the present invention, the carcass folded-up portion 3b can be wound around the bead core 2a, or can be sandwiched between a plurality of divided small bead cores. In the illustrated example, the end 3c of the carcass folded-up portion 3b is located radially outward from the radially outer end of the bead filler 2b and radially inward from the maximum width position of the tire. This allows the tire to be made lighter while ensuring the rigidity of the sidewall portion. On the other hand, in the present invention, the end 3c of the carcass folded-up portion 3b may be located radially inward from the outer end of the bead filler 2b in the tire radial direction, or may be located radially outward from the maximum tire width position. Alternatively, the end 3c of the carcass folded-up portion 3b may have an envelope structure in which it is located radially inward from the end of the belt 4 (for example, the end of the belt layer 4b) so as to be located between the carcass main body 2a and the belt 4 in the tire radial direction. Furthermore, when the carcass 3 is composed of a plurality of carcass plies, the positions (for example, tire radial positions) of the end 3c of the carcass folded-up portion 3b can be the same or different between the carcass plies. The number of cords in the carcass 3 is not particularly limited, but can be, for example, in the range of 20 to 60 cords / 50 mm. In addition, various structures can be adopted for the carcass line. For example, in the tire radial direction, the maximum carcass width position can be moved closer to the bead portion 2 side or closer to the tread 5 side. For example, the carcass maximum width position can be located in a range of 50% to 90% of the tire cross-sectional height from the bead base line outward in the tire radial direction. The above-mentioned "radial arrangement" is at an angle of 85° or more with respect to the tire circumferential direction, preferably 90° with respect to the tire circumferential direction.

[0023] The tire of this embodiment preferably has one or more inclined belt layers made of rubber-coated cords extending inclined with respect to the tire circumferential direction, and two layers are most preferable in terms of a balance between weight reduction and suppression of distortion of the ground contact surface shape. The belt layer may be one layer from the viewpoint of weight reduction, and may be three or more layers from the viewpoint of suppressing distortion of the ground contact surface shape. In the example shown in FIG. 2, the width in the tire width direction of the belt layer 4b on the outer side in the tire radial direction of the two belt layers 4a and 4b is smaller than the width in the tire width direction of the belt layer 4a on the inner side in the tire radial direction. On the other hand, the width in the tire width direction of the belt layer 4b on the outer side in the tire radial direction may be larger than or the same as the width in the tire width direction of the belt layer 4a on the inner side in the tire radial direction. The width in the tire width direction of the belt layer having the largest width in the tire width direction (belt layer 4a in the illustrated example) is preferably 90 to 115% of the ground contact width, and particularly preferably 100 to 105% of the ground contact width. The "ground contact width" refers to the distance in the tire width direction between the ground contact ends E. In this embodiment, the belt cords constituting the belt layers 4a and 4b are made of non-metallic cords. As an example of the non-metallic cord, an organic fiber cord such as Kevlar (registered trademark) nylon or aramid can be used. In this embodiment, the inclination angle of the belt cords of the belt layers 4a and 4b is preferably 10° or more with respect to the tire circumferential direction. In this embodiment, the inclination angle of the belt cords of the belt layers 4a and 4b is preferably high, specifically 20° or more with respect to the tire circumferential direction, preferably 35° or more, and particularly preferably in the range of 55° to 85° with respect to the tire circumferential direction. By setting the inclination angle to 20° or more (preferably 35° or more), the rigidity in the tire width direction can be increased, and the steering stability performance, especially during cornering, can be improved. In addition, the shear deformation of the interlayer rubber can be reduced, and the rolling resistance can be reduced.

[0024] In the illustrated example, the tread rubber constituting the tread 5 is made of one layer. On the other hand, in this embodiment, the tread rubber constituting the tread 5 may be formed by laminating a plurality of different rubber layers in the tire radial direction. The above-mentioned plurality of rubber layers may have different tangent loss, modulus, hardness, glass transition temperature, material, etc. The thickness ratio of the plurality of rubber layers in the tire radial direction may vary in the tire width direction, and only the bottom of the circumferential main groove, etc. may be a rubber layer different from the surroundings. The tread rubber constituting the tread 5 may be formed of a plurality of rubber layers different in the tire width direction. The above-mentioned plurality of rubber layers may have different tangent loss, modulus, hardness, glass transition temperature, material, etc. The width ratio of the plurality of rubber layers in the tire width direction may vary in the tire radial direction, and only limited areas such as the vicinity of the circumferential main groove, the vicinity of the ground contact edge, the shoulder land portion, and the center land portion may be a rubber layer different from the surroundings.

[0025] In the illustrated example, the tire 1 has three circumferential main grooves 6 extending in the tire circumferential direction. Specifically, one circumferential main groove 6 is provided on the tire equatorial plane CL, and one circumferential main groove 6 is provided in each shoulder region on both sides in the tire width direction. The groove width (opening width) of the circumferential main groove 6 is not particularly limited, but may be, for example, 2 mm to 5 mm. In the present invention, the number and arrangement of the circumferential main grooves 6 are not particularly limited to the above example. In addition, widthwise grooves extending in the tire width direction, sipes that are closed when the tire comes into contact with the ground, and the like may also be provided as appropriate.

[0026] The tire 1 of this embodiment has an inner liner 8 on the inner surface 7 of the tire (also simply referred to as the tire inner surface 7). The thickness of the inner liner 8 is preferably about 1.5 mm to 2.8 mm. This is because it is possible to effectively reduce interior noise of 80 to 100 Hz. The air permeability coefficient of the rubber composition constituting the inner liner 8 is 1.0×10 -14 cc cm / (cm 2 ·s·cmHg) or more, 6.5×10 -10 cc cm / (cm2 It is preferable to keep the temperature below 1.5°C (s·cmHg).

[0027] Here, as shown in FIG. 2, the tire includes a communication device 9. The communication device 9 may be configured to be capable of wireless communication with a predetermined device outside the tire 1, and the configuration of the communication device 9 is not particularly limited. In this embodiment, the communication device 9 is an RF tag. The RF tag is also called an RFID (Radio Frequency Identification) tag. The communication device 9 may be configured to include, for example, an IC chip that configures a control unit and a storage unit, and one or more antennas connected to the IC chip. For example, the communication device 9 may have an elongated shape as a whole, in which two antennas extending linearly, wavy, or spirally are provided so as to extend in opposite directions from the IC chip. The IC chip may also be operated by a dielectric electromotive force generated by electromagnetic waves received by one or more antennas. That is, the communication device 9 may be a passive communication device. Alternatively, the communication device 9 may further include a battery and may be capable of communication by generating electromagnetic waves using its own power. That is, the communication device 9 may be an active communication device. The communication device 9 may be covered with a covering rubber. The communication device 9 may be a sensor (for example, a sensor capable of detecting the temperature of a tire) or the like other than the RF tag.

[0028] In this embodiment, the communication device 9 is provided in the tread 5, more specifically, on the outer side in the tire radial direction than a belt layer 4b which is the outermost belt layer in the tire radial direction among one or more belt layers. The effects of the pneumatic radial tire for passenger cars according to this embodiment will be described below.

[0029] First, in the pneumatic radial tire for passenger cars of this embodiment, the tire section width SW is less than 165 (mm), and the ratio SW / OD of the tire section width SW to the outer diameter OD is 0.26 or less (or the relational expression, OD (mm) ≧ −0.0187 × SW (mm) 2+9.15×SW(mm)−380(mm) is satisfied). As a result, as described above, the fuel efficiency of the tire can be improved. In a narrow-width, large-diameter tire in which the SW and OD have the above-mentioned relationship, the deformation of the tread 5 is smaller than that of a wide-width, low-profile tire. Therefore, even if the communication device 9 is provided in the region, it is unlikely to be significantly deformed, and the durability of the communication device 9 can be improved. Furthermore, by arranging the communication device 9 in the tread 5 (particularly, on the tire radial direction outer side of the belt layer 4b, which is the outermost belt layer in the tire radial direction), communication from the road surface is improved. Here, if the belt cord is a metal cord such as a steel cord, the belt layer may interfere with communication of the communication device 9 provided in the tread 5. However, in this embodiment, a nonmetallic cord is used for the belt cord constituting the belt layer, so that the communication of the communication device 9 provided in the above position is not hindered. Furthermore, by disposing the communication device 9 in the tread (outside in the tire radial direction from the belt layer 4b which is the outermost in the tire radial direction), maintenance of the communication device 9 can be easily performed during retreading. In this way, according to the pneumatic radial tire for passenger cars of this embodiment, it is possible to achieve both durability and communication performance of the communication device.

[0030] In the above example, it is preferable that the tread surface of the tread has one or two circumferential main grooves extending in the tire circumferential direction, or has no circumferential main groove. This is because it is possible to secure a space in which the communication device 9 can be embedded, and it is easy to protect the communication device 9. In addition, since the communication device 9 can be replaced at the same time as retreading, it is possible to preserve the driving history, retread history, tread information, etc. Here, the "tread surface" refers to the surface extending over the entire circumference of the tire in the circumferential direction that comes into contact with the road surface when the tire is mounted on the rim, inflated to the specified internal pressure, and loaded with the maximum load. In addition, the "circumferential main groove" refers to a groove having a groove width (opening width) of 2 mm or more. Furthermore, "extending in the tire circumferential direction" includes cases where the groove extends in the tire circumferential direction, as well as cases where the groove extends at an angle of 5° or less with respect to the tire circumferential direction, and includes cases where the groove extends in various shapes such as a straight line and a zigzag shape.

[0031] <Tire-rim assembly> The tire-rim assembly here is formed by mounting the above-mentioned passenger car pneumatic radial tire on a rim. With this tire-rim assembly, it is possible to obtain the same effects as those described for the above-mentioned passenger car pneumatic radial tire. In this case, the internal pressure of the tire-rim assembly is preferably 200 kPa or more, more preferably 220 kPa or more, and even more preferably 280 kPa or more. This is because a high internal pressure can further reduce rolling resistance. On the other hand, it is preferable that the internal pressure of the tire-rim assembly is 350 kPa or less. This is because it can improve ride comfort.

[0032] <How to use pneumatic radial tires for passenger cars> The method of using the passenger car pneumatic radial tire here uses the passenger car pneumatic radial tire. According to the method of using the passenger car pneumatic radial tire, the same action and effect as that described for the passenger car pneumatic radial tire can be obtained. In this case, the internal pressure is preferably 200 kPa or more, more preferably 220 kPa or more, and even more preferably 280 kPa or more. This is because the rolling resistance can be further reduced by using a high internal pressure. On the other hand, it is preferable to use the internal pressure at 350 kPa or less. This is because the ride comfort can be improved.

[0033] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, in the illustrated example, one communication device is provided on each half of the tire width direction, with the tire equatorial plane CL as the boundary, but the communication devices 9 may be provided only on one half, or the number of communication devices 9 may be multiple. [Explanation of symbols]

[0034] 1: Pneumatic radial tires for passenger cars (tires), 2: bead portion, 2a: bead core, 2b: bead filler, 3: carcass, 4: belt; 4a, 4b: belt layer; 5: tread; 6: circumferential main groove; 7: tire inner surface; 8: inner liner; 9: communication device, CL: tire equatorial plane

Claims

1. A pneumatic radial tire for passenger vehicles having a belt consisting of one or more belt layers, a tread, and a communication device, The tire has a section width SW of less than 165 (mm), and a ratio SW / OD of the section width SW to the outer diameter OD of the tire is 0.26 or less, The belt cord constituting the belt layer is a non-metallic cord, A pneumatic radial tire for passenger cars, characterized in that the communication device is provided in the tread.

2. A pneumatic radial tire for passenger vehicles having a belt consisting of one or more belt layers, a tread, and a communication device, The tire has a section width SW of less than 165 (mm), The tire section width SW (mm) and the outer diameter OD (mm) are expressed by the following relational expression: OD(mm)≧-0.0187×SW(mm) ２ +9.15×SW(mm)-380(mm) Fulfilling The belt cord constituting the belt layer is a non-metallic cord, A pneumatic radial tire for passenger cars, characterized in that the communication device is provided in the tread.

3. 3. The pneumatic radial tire for passenger cars according to claim 1, wherein the tread surface has one or two circumferential main grooves extending in the tire circumferential direction, or the tread surface has no circumferential main grooves.

4. The pneumatic radial tire for passenger cars according to any one of claims 1 to 3, wherein the communication device is an RF tag.

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