JP7469598B2 - Pneumatic tires - Google Patents

Description

The present invention relates to a pneumatic tire equipped with a transponder, and more specifically, to a pneumatic tire that makes it possible to improve the durability of the tire while improving the communication capability and damage resistance of the transponder.

It has been proposed to embed an RFID tag (transponder) in a pneumatic tire (see, for example, Patent Document 1). When embedding a transponder in a tire, for example, if the transponder is placed between the carcass layer and the rubber layer of the sidewall portion or between the carcass layer and the inner liner layer, there is a problem that the durability of the tire is deteriorated due to the influence of stress concentration when the tire contacts the ground. In addition, if the transponder is placed near a metal tire component (for example, a bead core, etc.), there is a problem that the tire component and the transponder interfere with each other, deteriorating the communication performance of the transponder. Furthermore, if the transponder is placed on the outer side of the rolled-up portion of the carcass layer in the tire width direction, the transponder may be damaged in conjunction with damage to the sidewall portion.

Japanese Patent Application Laid-Open No. 7-137510

The object of the present invention is to provide a pneumatic tire that improves the durability of the tire while improving the communication performance and damage resistance of the transponder.

In order to achieve the above object, the pneumatic tire of the present invention comprises a tread portion extending circumferentially of the tire to form a ring, a pair of sidewall portions arranged on both sides of the tread portion, and a pair of bead portions arranged radially inward of the sidewall portions, a bead filler is arranged on the outer periphery of the bead core of each bead portion, at least one carcass layer is mounted between the pair of bead portions, and a plurality of belt layers are arranged on the outer periphery of the carcass layer in the tread portion, the pneumatic tire being characterized in that a transponder extending along the tire circumferential direction is provided on the inner surface of the tire, the transponder is arranged between a position 15 mm radially outward from the upper end of the bead core and a position 5 mm radially inward from an end of the belt layer, and the center of the transponder is arranged 10 mm or more circumferentially of the tire from the splice portion of the carcass layer .

In the present invention, a transponder is provided on the inner surface of the tire, extending along the tire circumferential direction, and the transponder is disposed between a position 15 mm radially outward from the upper end of the bead core and a position 5 mm radially inward from the end of the belt layer. This means that the transponder is located in a position where stress concentration is low when the tire is in contact with the ground, and adverse effects on tire durability can be reduced, improving tire durability. In addition, metal interference is unlikely to occur, and transponder communication can be ensured. Furthermore, damage to the transponder caused by damage to the sidewall portion can be prevented.

In the pneumatic tire of the present invention, the transponder is preferably disposed between a position 5 mm radially outward from the upper end of the bead filler and a position 5 mm radially inward from the end of the belt layer. This allows the transponder to be disposed in a flex zone where the rubber gauge is thin, and since this region experiences less attenuation of radio waves during transponder communication, the communication performance of the transponder can be effectively improved. In addition, damage to the transponder caused by damage to the inner liner layer during assembly to the rim can be prevented.

It is preferable that the center of the transponder is located at least 10 mm away from the splice portion of the tire component in the tire circumferential direction. This can effectively improve the durability of the tire.

It is preferable that the distance between the center of the cross section of the transponder and the inner surface of the tire is 1 mm or more. This effectively improves tire durability and prevents damage to the transponder caused by damage to the inner liner layer when the tire is assembled to the rim.

The transponder is covered with a covering layer, and it is preferable that the relative dielectric constant of the covering layer is 7 or less. This protects the transponder with the covering layer, improving the durability of the transponder, while ensuring the radio wave transparency of the transponder and effectively improving the communication performance of the transponder.

The transponder is covered with a coating layer, and the thickness of the coating layer is preferably 0.5 mm to 3.0 mm. This can effectively improve the communication performance of the transponder.

The transponder has an IC board that stores data and an antenna that transmits and receives data, and the antenna is preferably spiral-shaped. This allows it to follow the deformation of the tire while it is running, improving the durability of the transponder.

1 is a meridian half cross-sectional view showing a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a meridian cross-sectional view illustrating the pneumatic tire of FIG. 1 . FIG. 2 is an equatorial cross-sectional view that illustrates the pneumatic tire of FIG. 1 . 2 is an enlarged cross-sectional view showing a transponder disposed in the pneumatic tire of FIG. 1 . 1A and 1B are perspective views showing a transponder that can be disposed in a pneumatic tire according to the present invention. FIG. 2 is an explanatory diagram showing radial positions of transponders in a test tire.

The configuration of the present invention will be described in detail below with reference to the attached drawings. Figures 1 to 4 show a pneumatic tire according to an embodiment of the present invention.

As shown in FIG. 1, the pneumatic tire of this embodiment has a tread portion 1 that extends in the circumferential direction of the tire and forms an annular shape, a pair of sidewall portions 2 arranged on both sides of the tread portion 1, and a pair of bead portions 3 arranged on the radially inner side of the sidewall portions 2.

Between a pair of bead portions 3, at least one carcass layer 4 (one layer in FIG. 1) is installed, which is made of a plurality of carcass cords arranged in the radial direction. Organic fiber cords such as nylon and polyester are preferably used as the carcass cords that make up the carcass layer 4. An annular bead core 5 is embedded in each bead portion 3, and a bead filler 6 made of a rubber composition with a triangular cross section is arranged on the outer periphery of the bead core 5.

On the other hand, multiple belt layers 7 (two layers in FIG. 1) are embedded on the tire outer circumferential side of the carcass layer 4 in the tread portion 1. The belt layers 7 include multiple reinforcing cords that are inclined with respect to the tire circumferential direction, and are arranged so that the reinforcing cords cross each other between the layers. In the belt layers 7, the inclination angle of the reinforcing cords with respect to the tire circumferential direction is set in the range of 10° to 40°, for example. Steel cords are preferably used as the reinforcing cords of the belt layers 7.

At least one belt cover layer 8 (two layers in FIG. 1) is arranged on the tire outer periphery side of the belt layer 7, in which reinforcing cords are arranged at an angle of, for example, 5° or less with respect to the tire circumferential direction, in order to improve high-speed durability. In FIG. 1, the belt cover layer 8 located on the inner side in the tire radial direction constitutes a full cover that covers the entire width of the belt layer 7, and the belt cover layer 8 located on the outer side in the tire radial direction constitutes an edge cover layer that covers only the ends of the belt layer 7. As the reinforcing cords of the belt cover layer 8, organic fiber cords such as nylon and aramid are preferably used.

In the above pneumatic tire, both ends 4e of the carcass layer 4 are folded back from the inside to the outside of the tire around each bead core 5, and are arranged to encase the bead core 5 and the bead filler 6. The carcass layer 4 includes a main body portion 4A that extends from the tread portion 1 through each sidewall portion 2 to each bead portion 3, and a rolled-up portion 4B that is rolled up around the bead core 5 in each bead portion 3 and extends toward each sidewall portion 2.

An inner liner layer 9 is disposed along the carcass layer 4. In other words, the inner liner layer 9 forms the inner surface of the tire. A cap tread rubber layer 11 is disposed in the tread portion 1, a sidewall rubber layer 12 is disposed in the sidewall portion 2, and a rim cushion rubber layer 13 is disposed in the bead portion 3. The rubber layer 10 disposed on the outside of the carcass layer 4 in the sidewall portion 2 includes the sidewall rubber layer 12 and the rim cushion rubber layer 13.

In the above pneumatic tire, a transponder 20 is disposed on the inner surface of the tire, that is, on the inside of the inner liner layer 9. The transponder 20 is vulcanized and bonded to the inner surface of the tire via a rubber layer during tire molding, and is attached integrally to the inner surface of the tire (inner liner layer 9). The transponder 20 is disposed between a position P1 15 mm outward from the upper end 5e (the outer end in the tire radial direction) of the bead core 5 and a position P2 5 mm inward from the terminal 7e of the belt layer 7 in the tire radial direction, as a region in the tire radial direction. That is, the transponder 20 is disposed in the region S1 shown in FIG. 2. The transponder 20 extends along the tire circumferential direction. The transponder 20 may be disposed so as to be inclined in the range of -10° to 10° with respect to the tire circumferential direction.

As the transponder 20, for example, an RFID (Radio Frequency Identification) tag can be used. As shown in Figs. 5(a) and (b), the transponder 20 has an IC board 21 that stores data and an antenna 22 that transmits and receives data in a non-contact manner. By using such a transponder 20, information about the tire can be written or read at appropriate times, and the tire can be managed efficiently. RFID is an automatic recognition technology that is composed of a reader/writer with an antenna and a controller, and an ID tag with an IC board and an antenna, and can communicate data wirelessly.

The overall shape of the transponder 20 is not particularly limited, and may be, for example, columnar or plate-shaped as shown in Figs. 5(a) and (b). In particular, the columnar transponder 20 shown in Fig. 5(a) is preferable because it can follow the deformation of the tire in each direction. In this case, the antenna 22 of the transponder 20 protrudes from both ends of the IC board 21 and has a spiral shape. This allows it to follow the deformation of the tire during driving, improving the durability of the transponder 20. Furthermore, communication can be ensured by appropriately changing the length of the antenna 22.

In the above-mentioned pneumatic tire, a transponder 20 is provided on the inner surface of the tire, extending in the tire circumferential direction. The transponder 20 is disposed between a position P1 15 mm radially outward from the upper end 5e of the bead core 5 and a position P2 5 mm radially inward from the end 7e of the belt layer 7. Therefore, the transponder 20 is located in a portion where stress concentration is low when the tire is in contact with the ground, and adverse effects on tire durability can be reduced, thereby improving tire durability. In addition, metal interference is unlikely to occur, and communication of the transponder 20 can be ensured. Furthermore, damage to the transponder 20 caused by damage to the sidewall portion 2 can be prevented.

Here, if the transponder 20 is positioned radially inward from position P1, metallic interference with the rim flange occurs, tending to reduce the communication performance of the transponder 20. Also, if the transponder 20 is positioned radially outward from position P2, metallic interference with the belt layer 7 occurs, tending to reduce the communication performance of the transponder 20.

In the above pneumatic tire, the transponder 20 is preferably disposed between a position P3 5 mm radially outward from the upper end 6e of the bead filler 6 and a position P2 5 mm radially inward from the end 7e of the belt layer 7. That is, the transponder 20 is preferably disposed in the region S2 shown in FIG. 2. The region S2 is a flex zone with a thin rubber gauge, and when the transponder 20 is disposed in the region S2, attenuation of radio waves during communication by the transponder 20 is reduced, and the communication performance of the transponder 20 can be effectively improved. In addition, damage to the transponder 20 caused by damage to the inner liner layer 9 during assembly to the rim can be prevented.

As shown in FIG. 3, there are a number of splice sections on the circumference of the tire, which are formed by overlapping the ends of tire constituent members. FIG. 3 shows the tire circumferential position Q of each splice section. It is preferable that the center of the transponder 20 is located 10 mm or more away from the splice section of the tire constituent member in the tire circumferential direction. That is, the transponder 20 is preferably located in the region S3 shown in FIG. 3. Specifically, it is preferable that the IC board 21 constituting the transponder 20 is located 10 mm or more away from the position Q in the tire circumferential direction. Furthermore, it is more preferable that the entire transponder 20 including the antenna 22 is located 10 mm or more away from the position Q in the tire circumferential direction, and it is most preferable that the entire transponder 20 in a state where it is covered with the covering rubber is located 10 mm or more away from the position Q in the tire circumferential direction. In addition, it is preferable that the tire constituent member located away from the transponder 20 is the inner liner layer 9 or the carcass layer 4 located adjacent to the transponder 20. By positioning the transponder 20 away from the splice portion of the tire components in this way, tire durability can be effectively improved.

In the embodiment of FIG. 3, the tire circumferential positions Q of the splices of each tire component are arranged at equal intervals, but this is not limited to the embodiment. The tire circumferential positions Q can be set at any position, and in any case, the transponder 20 is arranged so as to be 10 mm or more away from the splices of each tire component in the tire circumferential direction.

As shown in FIG. 4, the distance d between the center of the cross section of the transponder 20 and the inner surface of the tire is preferably 1 mm or more. By separating the transponder 20 from the inner surface of the tire in this manner, the durability of the tire can be effectively improved and damage to the transponder 20 caused by damage to the inner liner layer 9 during assembly to the rim can be prevented.

The transponder 20 may also be coated with a coating layer 23. This coating layer 23 covers the entire transponder 20 by sandwiching both the front and back sides of the transponder 20. The coating layer 23 may be made of rubber having the same physical properties as the rubber constituting the tire components such as the sidewall rubber layer 12 and the rim cushion rubber layer 13, or may be made of rubber having different physical properties. By protecting the transponder 20 with the coating layer 23 in this way, the durability of the transponder 20 can be improved.

In the above pneumatic tire, when the transponder 20 is covered with the covering layer 23, the relative dielectric constant of the covering layer 23 is preferably 7 or less, and more preferably 2 to 5. By appropriately setting the relative dielectric constant of the covering layer 23 in this way, the radio wave permeability when the transponder 20 emits radio waves can be ensured, and the communication performance of the transponder 20 can be effectively improved. The relative dielectric constant of the rubber constituting the covering layer 23 is 860 MHz to 960 MHz at room temperature. Here, the room temperature conforms to the standard conditions of the JIS standard, which are 23 ± 2°C and 60% ± 5% RH. The relative dielectric constant of the rubber is measured after being treated for 24 hours at 23°C and 60% RH. The above-mentioned range of 860 MHz to 960 MHz corresponds to the currently allocated frequency of UHF RFID, but if the above-mentioned allocated frequency is changed, the relative dielectric constant of the range of the allocated frequency can be specified as above.

In addition, when the transponder 20 is covered with the covering layer 23, the thickness t of the covering layer 23 is preferably 0.5 mm to 3.0 mm, and more preferably 1.0 mm to 2.5 mm. Here, the thickness t of the covering layer 23 is the rubber thickness at the position including the transponder 20, and is, for example, the rubber thickness obtained by summing the thickness t1 and the thickness t2 on a straight line passing through the center of the transponder 20 and perpendicular to the tire inner surface as shown in FIG. 4. In this way, by appropriately setting the thickness t of the covering layer 23, the communication properties of the transponder 20 can be effectively improved. Here, if the thickness t of the covering layer 23 is thinner than 0.5 mm, the effect of improving the communication properties of the transponder 20 cannot be obtained, and conversely, if the thickness t of the covering layer 23 exceeds 3.0 mm, the covering layer 23 including the transponder 20 will excessively protrude from the tire inner surface, which is not preferable. The cross-sectional shape of the covering layer 23 is not particularly limited, but for example, a triangle, a rectangle, a trapezoid, or a spindle shape can be adopted. The covering layer 23 in FIG. 4 has a rectangular cross-sectional shape.

In the above embodiment, an example of a pneumatic tire having one carcass layer is shown, but this is not particularly limited, and two carcass layers may be used. Also, in the above embodiment, an example is shown in which the end 4e of the turned-up portion 4B of the carcass layer 4 is positioned in the middle of the sidewall portion 2 beyond the upper end 6e of the bead filler 6, but this is not limited, and the tire may be positioned at any height.

The tire size is 265/40ZR20, and the tire has a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions arranged on both sides of the tread portion, and a pair of bead portions arranged on the tire radial inside of these sidewall portions. A bead filler is arranged on the outer periphery of the bead core of each bead portion, a carcass layer is mounted between the pair of bead portions, and multiple belt layers are arranged on the outer periphery of the carcass layer in the tread portion. A transponder is provided extending along the tire circumferential direction, and tires of Comparative Examples 1 to 5 and Examples 1 to 14 were manufactured with the transponder position (tire width direction, tire radial direction, and tire circumferential direction), the distance between the transponder and the tire inner surface, the relative dielectric constant of the coating layer, the thickness of the coating layer, and the transponder shape set as shown in Tables 1 and 2.

In Tables 1 and 2, when the transponder position (tire width direction) is "W", the transponder is disposed on the tire inner surface (inside the inner liner layer), when the transponder position (tire width direction) is "X", the transponder is disposed between the carcass layer and the inner liner layer, when the transponder position (tire width direction) is "Y", the transponder is disposed between the carcass layer and the sidewall rubber layer in contact with the sidewall rubber layer, and when the transponder position (tire width direction) is "Z", the transponder is disposed between the carcass layer and the rim cushion rubber layer in contact with the rim cushion rubber layer. In Tables 1 and 2, the transponder positions (tire radial direction) correspond to the positions A to E shown in FIG. 6. Furthermore, in Tables 1 and 2, the transponder position (tire circumferential direction) indicates the distance [mm] measured in the tire circumferential direction from the center of the transponder to the splice portion of the tire constituent member.

For these test tires, tire evaluation (durability) and transponder evaluation (communication performance, durability, external damage resistance, and damage resistance) were carried out using the following test methods, and the results are shown in Tables 1 and 2.

Durability (tires and transponders):
Each test tire was mounted on a standard rim wheel, and a running test was performed using a drum test machine under conditions of an air pressure of 120 kPa, 102% of the maximum load, and a running speed of 81 km, and then the running distance when the tire malfunctioned was measured. The evaluation results were shown in four stages: when the running distance reached 6480 km, it was indicated as "◎ (excellent)", when the running distance was 4050 km or more and less than 6480 km, it was indicated as "○ (good)", when the running distance was 3240 km or more and less than 4050 km, it was indicated as "△ (passable)", and when the running distance was less than 3240 km, it was indicated as "× (unacceptable)". Furthermore, after the running was completed, the outer surface of each test tire was visually inspected to confirm whether the tire malfunction originated from the transponder. The evaluation results indicated the presence or absence of the malfunction.

Communication (transponder):
For each test tire, a reader/writer was used to communicate with the transponder. Specifically, the longest communication distance was measured with the reader/writer at an output of 250 mW and a carrier frequency of 860 MHz to 960 MHz. The evaluation results were shown in three stages: a communication distance of 500 mm or more was indicated as "◎ (excellent)", a communication distance of 150 mm or more but less than 500 mm was indicated as "○ (good)", and a communication distance of less than 150 mm was indicated as "△ (fair)".

Trauma resistance (transponder):
Each test tire was mounted on a standard rim wheel and attached to a test vehicle, and a running test was performed in which the tire ran over a curb with a height of 100 mm under the conditions of an air pressure of 230 kPa and a running speed of 20 km/h. After the run, damage to the outer surface of the tire corresponding to the placement of the transponder was confirmed. The evaluation results showed the presence or absence of damage to the outer surface of the tire caused by the placement of the transponder.

Damage resistance during assembly (transponder):
For each test tire, the inner surface of the tire corresponding to the location of the transponder was visually inspected when the rim was replaced. The evaluation results showed the presence or absence of damage to the transponder caused by damage to the inner liner.

As can be seen from Tables 1 and 2, the pneumatic tires of Examples 1 to 14 had a good balance of improved tire durability, transponder communication performance, and transponder resistance to external damage. In the pneumatic tire of Example 6, the distance between the center of the transponder and the inner surface of the tire was set long, improving the transponder's resistance to damage. In the pneumatic tire of Example 13, the thickness of the coating layer covering the transponder was set thick, so the coating layer including the transponder protruded from the inner surface of the tire by a large amount, making it more susceptible to damage when assembled to the rim. In the pneumatic tire of Example 14, a columnar transponder was used, improving the durability of the transponder and eliminating any failures originating from the transponder.

On the other hand, in Comparative Examples 1 to 3, the transponder was embedded in the tire, and the durability of the tire was deteriorated due to the effect of stress concentration when the tire touched the ground. In Comparative Examples 1 to 5, the position of the transponder in the tire radial direction was outside the region specified in the present invention, and the communication performance of the transponder was deteriorated. In Comparative Examples 1 and 2, the transponder was positioned between the carcass layer and the sidewall rubber layer or the rim cushion rubber layer in contact with the rubber layer, and the external damage resistance of the transponder was deteriorated.

Reference Signs List 1 tread portion 2 sidewall portion 3 bead portion 4 carcass layer 4A main body portion 4B turn-up portion 5 bead core 6 bead filler 7 belt layer 20 transponder CL tire center line P1 to P3 positions

Claims (6)

A pneumatic tire comprising a tread portion extending in a circumferential direction of the tire and forming an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed radially inward of the sidewall portions, a bead filler disposed on an outer periphery of a bead core of each bead portion, at least one carcass layer is fitted between the pair of bead portions, and a plurality of belt layers are disposed on the outer periphery of the carcass layer in the tread portion,
A pneumatic tire characterized in that a transponder extending along a tire circumferential direction is provided on an inner surface of the tire, the transponder is disposed between a position 15 mm radially outward from an upper end of the bead core and a position 5 mm radially inward from an end of the belt layer, and a center of the transponder is disposed 10 mm or more away from a splice portion of the carcass layer in the tire circumferential direction . The pneumatic tire according to claim 1, characterized in that the transponder is disposed between a position 5 mm radially outward from the upper end of the bead filler and a position 5 mm radially inward from the end of the belt layer. 3. The pneumatic tire according to claim 1, wherein a distance between a cross-sectional center of the transponder and an inner surface of the tire is 1 mm or more. 4. The pneumatic tire according to claim 1 , wherein the transponder is covered with a covering layer, and the covering layer has a relative dielectric constant of 7 or less. 5. The pneumatic tire according to claim 1 , wherein the transponder is covered with a covering layer, and the covering layer has a thickness of 0.5 mm to 3.0 mm. 6. The pneumatic tire according to claim 1 , wherein the transponder has an IC board for storing data and an antenna for transmitting and receiving data, and the antenna is spiral-shaped.

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