JP2010184628A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect distortion of each of the places composing a pneumatic tire according to the situation or the purpose. <P>SOLUTION: In the pneumatic tire 1, an optical fiber 9 having a diffraction grating part 92 in which a reflection wavelength of light changes with expansion and contraction is embedded in the inside of the tire. At least one of the cords is replaced with the optical fiber 9 in a structure such as a bead core 51 having a plurality of cords, a carcass layer 6, a belt layer 7 and a belt reinforcing layer 8. In such pneumatic tire 1, the change of the distortion or the temperature caused in the structure can be detected according to the situation or the purpose by replacing at least one of the cords of the structure with the optical fiber 9. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pneumatic tire that can detect distortions and temperature changes in various parts of a tire.

  A pneumatic tire is assembled to a rim and is mounted on a vehicle in a state where air is filled therein. Then, when the vehicle travels, it rolls according to the motion of the vehicle and generates distortion. In order to know the performance of the pneumatic tire, it is desired to obtain distortion in a state where the vehicle is mounted on the vehicle.

  2. Description of the Related Art Conventionally, a tire strain detection sensor system that detects strain generated in a solid portion of a tire is known. Such a tire strain detection sensor system uses an optical fiber in which a fiber Bragg grating (FBG) whose reflection wavelength changes according to strain is formed, and the optical fiber is embedded in an inner layer of a tire. (For example, refer to Patent Document 1).

JP 2006-15822 A

  In the tire strain detection sensor system of Patent Document 1, it is indicated that the optical axis of the FBG portion of the optical fiber is arranged in the tire radial direction, the tire circumferential direction, and the tire axial direction. Furthermore, in Patent Document 1, an optical fiber is wound and arranged in the tire circumferential direction, extends from one side to multiple sides in the tire width direction, shifts by a predetermined pitch in the tire circumferential direction, and then extends in the tire width direction to zigzag. It is shown that the tires are arranged in a zigzag extending obliquely in the tire width direction.

  However, a pneumatic tire is composed of a rubber material that forms a tread portion, a shoulder portion, a sidewall portion, a bead portion, and the like, and a cord that forms a carcass layer, a belt layer, a belt cover layer, a bead core, each reinforcing layer, and the like. . And in the sensor system for tire distortion detection of patent documents 1, arrangement of an optical fiber which detects distortion of these various places is not shown. Therefore, in the sensor system shown in Patent Document 1, it is difficult to detect the distortion of each place constituting the pneumatic tire according to the situation and purpose.

  This invention is made | formed in view of the above, Comprising: It aims at providing the pneumatic tire which can detect the distortion of the various places which comprise a pneumatic tire according to a condition or the objective.

  In order to solve the above-described problems and achieve the object, the pneumatic tire of the present invention is a pneumatic tire in which an optical fiber in which a diffraction grating portion in which a reflection wavelength of light changes due to expansion and contraction is formed is embedded, A structure having a plurality of cords is characterized in that at least one of the cords is replaced with the optical fiber.

  According to this pneumatic tire, it is possible to detect a strain and a change in temperature generated in the structure according to the situation and purpose. Moreover, since at least one of the cords of the structure is replaced with an optical fiber, it is possible to minimize the mechanical hindrance to the structure.

  In the pneumatic tire according to the present invention, at least one of the bundled cords is arranged in the optical fiber.

  According to this pneumatic tire, the optical fiber is usually covered with a protective elastic body (rubber, etc.) around the core, but by replacing at least one of the bundled cords with an optical fiber. The cord protects the optical fiber core. For this reason, the elastic body interposed between the cord and the core can be reduced as much as possible. When there are many elastic bodies interposed between the cord and the core, when the strain generated in the entire bundled cord is transmitted to the diffraction grating section through the elastic body, a time delay occurs in the transmission of the strain to the diffraction grating section. Detection accuracy may be reduced. In this respect, when the elastic body is small, the distortion generated in the entire bundled cord is easily transmitted directly to the diffraction grating part, and no time delay occurs in the transmission of the distortion to the diffraction grating part. As a result, detection accuracy can be improved.

  In the pneumatic tire of the present invention, the cord is a twisted cord in which a plurality of cords are twisted, and at least one of the twisted cords is replaced with the optical fiber.

  According to this pneumatic tire, the cord protects the core of the optical fiber by replacing at least one of the twisted cords with the optical fiber. For this reason, the elastic body interposed between the cord and the core can be reduced as much as possible. If there are many elastic bodies interposed between the cord and the core, when the strain generated in the entire twisted cord is transmitted to the diffraction grating section via the elastic body, a time delay occurs in the transmission of the strain to the diffraction grating section. There is a possibility that the detection accuracy is lowered. In this respect, if the elastic body is small, the strain generated in the entire twisted cord is easily transmitted directly to the diffraction grating portion, and there is no time delay in transmitting the strain to the diffraction grating portion. As a result, detection accuracy can be improved.

  In order to solve the above-described problems and achieve the object, the pneumatic tire of the present invention is a pneumatic tire in which an optical fiber in which a diffraction grating portion in which a reflection wavelength of light changes due to expansion and contraction is formed is embedded therein, In the tread rubber forming the tread portion, the optical fiber is disposed along a tire circumferential direction, a tire width direction, or a bias direction.

  According to this pneumatic tire, it is possible to detect the strain and temperature change of the tread rubber in the tire circumferential direction, the tire width direction or the bias direction according to the situation and purpose.

  In the pneumatic tire of the present invention, the tread rubber is formed by laminating different types of tread rubber layers in the tire radial direction, and the optical fiber is disposed in each tread rubber layer.

  According to this pneumatic tire, it is possible to detect distortion and temperature change of each laminated tread rubber layer.

  In the pneumatic tire according to the present invention, the optical fiber is disposed along the extending direction of the groove immediately below the groove provided in the tread portion.

  The tread rubber directly under the groove often has a large distortion even in the tread portion. For this reason, as in this pneumatic tire, it is useful to detect the distortion of the tread rubber and the temperature change by arranging the optical fiber directly under the groove along the extending direction of the groove.

  In the pneumatic tire of the present invention, a land portion is formed by a groove provided in the tread portion, and the optical fiber is arranged along an uneven shape formed by the groove and the land portion.

  According to this pneumatic tire, it is possible to detect a distortion in the land portion and a change in temperature when the vehicle equipped with the pneumatic tire is driven or braked.

  In order to solve the above-described problems and achieve the object, the pneumatic tire of the present invention is a pneumatic tire in which an optical fiber in which a diffraction grating portion in which a reflection wavelength of light changes due to expansion and contraction is formed is embedded, A pneumatic tire characterized in that the optical fiber is disposed along a tire circumferential direction, a tire radial direction, or a bias direction inside a rubber forming a shoulder portion.

  According to this pneumatic tire, it is possible to detect a strain and a change in temperature in the tire circumferential direction, the tire radial direction or the bias direction of the rubber forming the shoulder according to the situation and purpose.

  In order to solve the above-described problems and achieve the object, the pneumatic tire of the present invention is a pneumatic tire in which an optical fiber in which a diffraction grating portion in which a reflection wavelength of light changes due to expansion and contraction is formed is embedded, The optical fiber is arranged along the tire circumferential direction, the tire radial direction, or the bias direction inside the rubber forming the sidewall portion.

  According to this pneumatic tire, it is possible to detect a strain or temperature change in the tire circumferential direction, the tire radial direction, or the bias direction of the rubber forming the sidewall according to the situation or purpose.

  In order to solve the above-described problems and achieve the object, the pneumatic tire of the present invention is a pneumatic tire in which an optical fiber in which a diffraction grating portion in which a reflection wavelength of light changes due to expansion and contraction is formed is embedded, The optical fiber is arranged along the tire circumferential direction inside the rubber forming the bead portion.

  According to this pneumatic tire, it is possible to detect distortion in the tire circumferential direction of the rubber forming the bead portion and a change in temperature according to the situation and purpose.

  The pneumatic tire according to the present invention can detect distortions in various places constituting the pneumatic tire in accordance with the situation and purpose.

FIG. 1 is a meridional sectional view of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a plan view of the pneumatic tire according to the embodiment of the present invention. FIG. 3 is a schematic view of an optical fiber embedded in the pneumatic tire according to the embodiment of the present invention. FIG. 4 is a schematic view showing an arrangement of optical fibers of the pneumatic tire according to the embodiment of the present invention. FIG. 5 is a schematic view showing the arrangement of the optical fibers of the pneumatic tire according to the embodiment of the present invention. FIG. 6 is a schematic view showing an arrangement of optical fibers of the pneumatic tire according to the embodiment of the present invention.

  Embodiments of a pneumatic tire according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. The constituent elements of this embodiment include those that can be easily replaced by those skilled in the art or those that are substantially the same. In addition, a plurality of modifications described in this embodiment can be arbitrarily combined within a range obvious to those skilled in the art.

  In the following description, the tire radial direction refers to a direction orthogonal to the rotation axis, the tire radial inner side is the side toward the rotation axis in the tire radial direction, and the tire radial outer side is the rotation axis in the tire radial direction. The side away from. Further, the tire width direction refers to a direction parallel to the rotation axis (not shown) of the pneumatic tire 1, and the inner side in the tire width direction is the side toward the tire equator plane (tire equator line) C in the tire width direction, The outer side in the tire width direction refers to the side away from the tire equatorial plane C in the tire width direction. The tire circumferential direction is a circumferential direction with the rotation axis as a central axis.

  The pneumatic tire 1 described below is configured to be substantially symmetric with respect to the tire equatorial plane C. The tire equatorial plane C is a plane that is orthogonal to the rotational axis of the pneumatic tire 1 and passes through the center of the tire width of the pneumatic tire 1. The tire width is the width in the tire width direction between the portions located outside in the tire width direction, that is, the distance between the portions farthest from the tire equatorial plane C in the tire width direction. The tire equator line is a line on the tire equator plane C and along the circumferential direction of the pneumatic tire. In the present embodiment, the same sign “C” as that of the tire equator plane is attached to the tire equator line. Since the pneumatic tire 1 described below is configured to be substantially symmetric about the tire equatorial plane C, the pneumatic tire 1 is cut along a plane passing through the rotation axis of the pneumatic tire 1. In the meridional sectional view (FIG. 1), only one side (right side in FIG. 1) centered on the tire equatorial plane C is illustrated and only one side is described, and the other side (left side in FIG. 1). Description of is omitted.

  The pneumatic tire 1 of the present embodiment has a tread portion 2 as shown in FIG. The tread portion 2 is made of a rubber material and is exposed at the outermost side in the tire radial direction of the pneumatic tire 1, and the surface thereof is the contour of the pneumatic tire 1. The surface of the tread portion 2 is formed as a tread surface 21 that is a surface that comes into contact with the road surface when a vehicle (not shown) on which the pneumatic tire 1 is mounted travels.

  The tread surface 21 is provided with a plurality of main grooves 22 that are straight grooves extending in the tire circumferential direction and parallel to the tire equator line C. In the present embodiment, four main grooves 22 are provided on the tread surface 21. A plurality of rib-like land portions 23 extending along the tire circumferential direction and parallel to the tire equator line C are formed on the tread surface 21 by the plurality of main grooves 22.

  In the tread surface 21, as shown in FIG. 2, a land portion 23 is formed in a block shape by a lug groove 24 communicating with the main groove 22. Further, a protruding groove 25 that communicates with one main groove 22 and is inclined with respect to the tire width direction may be provided.

  Further, as shown in FIG. 1, a shoulder portion 3, sidewall portions 4 and bead portions 5 that are sequentially continuous from the shoulder portions 3 are provided on both sides of the tread portion 2 in the tire width direction. The pneumatic tire 1 includes a carcass layer 6, a belt layer 7, and a belt reinforcing layer 8 therein.

  The shoulder portion 3 is a portion on both outer sides in the tire width direction of the tread portion 2. Further, the sidewall portion 4 is exposed at the outermost side in the tire width direction of the pneumatic tire 1. The bead unit 5 includes a bead core 51 and a bead filler 52. The bead core 51 is formed by winding a bead cord 51a (see FIG. 4), which is a steel wire, in a ring shape. The bead filler 52 is disposed in a space formed by folding the end of the carcass layer 6 outward in the tire width direction at the position of the bead core 51.

  The carcass layer 6 is configured such that each tire width direction end portion is folded at the position of the pair of bead portions 5 and is wound around in a toroidal shape in the tire circumferential direction to form a tire skeleton. The carcass layer 6 is made by covering organic fibers (nylon, polyester, rayon, etc.), a composite of two or more organic fibers, or a carcass cord (not shown) such as steel with a rubber material. A plurality of carcass cords are arranged side by side in the tire circumferential direction while being orthogonal to the tire equator line C of the pneumatic tire 1 and along the tire meridian direction (tire width direction). It should be noted that the carcass cord has an angle with respect to the tire equator line C (tire circumferential direction) substantially 90 [degrees], and is −5 [degrees] to +5 [degrees] with respect to 90 degrees with respect to the tire equator line C Includes range angles. Further, the carcass layer 6 is composed of a single layer as shown in FIG. 1, but may have a multilayer structure in order to improve tire rigidity.

  The belt layer 7 has a multilayer structure in which at least two belts 71 and 72 are laminated, and is disposed on the outer side in the tire radial direction which is the outer periphery of the carcass layer 6, and covers the carcass layer 6 in the tire circumferential direction in the tread portion 2. is there. The belts 71 and 72 are made of organic fibers (nylon, polyester, rayon, etc.), a composite of two or more organic fibers, or a belt cord (not shown) such as steel covered with a rubber material. It is arranged along the bias direction at a predetermined angle with respect to the tire circumferential direction, that is, the tire equator line C. Further, the belts 71 and 72 are arranged with their cords inclined in opposite directions with respect to the tire equator line C. Further, the belt layer 7 is composed of two layers as shown in FIG. 1, but may have a structure of three or more layers in order to improve tire rigidity.

  The belt reinforcing layer 8 is disposed on the outer side in the tire radial direction which is the outer periphery of the belt layer 7 and covers the belt layer 7 in the tire circumferential direction. The belt reinforcing layer 8 is formed by covering a reinforcing cord (not shown) such as organic fiber (nylon, polyester, rayon, etc.), a composite of two or more organic fibers or steel with a rubber material, and the cord is a tire. The tires are arranged along the tire circumferential direction so as to have an angle of substantially 0 degrees (angle with respect to the tire circumferential direction is ± 5 [degrees] or less) with respect to the tire equator line C. The belt reinforcing layer 8 may be composed of one layer, but may have a multilayer structure in order to further reinforce the end portion of the belt layer 7. The belt reinforcing layer 8 in the present embodiment is composed of two belt reinforcing layers 81 and 82 at both ends in the tire width direction as shown in FIG.

  In the pneumatic tire 1 of the present embodiment having such a configuration, an optical fiber 9 shown in FIG. 3 is embedded therein. The optical fiber 9 is formed with a fiber Bragg grating (FBG) 92 as a diffraction grating portion in which a diffraction grating having regular stripes is provided on a core 91. The fiber Bragg grating 92 has only a specific wavelength that matches the period (refractive index) of the diffraction grating among various wavelengths of light that is input from one end side through the core 91 of the optical fiber 9 and transmitted to the other end side. Reflected to one end side. The period of the diffraction grating of the fiber Bragg grating 92 expands and contracts due to strain and temperature, and the reflection wavelength of light changes with the expansion and contraction. For this reason, the optical fiber 9 in which the fiber Bragg grating 92 is formed can be used as a sensor that detects changes in strain and temperature by measuring changes in the reflected wavelength of light. In addition, by forming a plurality of fiber Bragg gratings 92 having different diffraction grating periods (refractive indices) in the length direction of one optical fiber 9, a plurality of locations in one length direction of the optical fiber 9 can be obtained. It is possible to detect strain and temperature changes. In addition, the output of the input light to the optical fiber 9 embedded in the pneumatic tire 1 and the measurement of the reflected light can be performed via a rim (not shown) assembled to the pneumatic tire 1.

  Hereinafter, the arrangement of the optical fiber 9 on the pneumatic tire 1 will be described. In the pneumatic tire 1 of the present embodiment, at least one of the cords of the structure having a plurality of cords is replaced with the optical fiber 9.

  The structure having a plurality of cords includes a bead core 51, a carcass layer 6, a belt layer 7, and a belt reinforcing layer 8. That is, in the bead core 51, at least one of the bead cords 51 a is replaced with the optical fiber 9. In the carcass layer 6, at least one of the carcass cords is replaced with an optical fiber 9. In the belt layer 7, at least one of the belt cords is replaced with the optical fiber 9. In the belt reinforcing layer 8, at least one of the reinforcing cords is replaced with the optical fiber 9.

  In the bead core 51, it is possible to detect distortion and temperature change in the tire circumferential direction in the bead cord 51a. Moreover, in the carcass layer 6, the distortion and temperature change which arise in the extending direction (tire width direction) of the carcass cord can be detected according to the situation and purpose. Further, in the belt layer 7, it is possible to detect strain and temperature changes that occur in the belt cord extending direction (bias direction). Moreover, in the belt reinforcement layer 8, the distortion and temperature change which arise in the extension direction (tire circumferential direction) of a reinforcement cord are detectable.

  According to the pneumatic tire 1, it is possible to detect a distortion or a change in temperature that occurs in a structure having a cord in accordance with the situation or purpose. Moreover, since at least one of the cords of the structure is replaced with the optical fiber 9, it is possible to minimize the mechanical hindrance to the structure.

  In the pneumatic tire 1 in which at least one of the cords of the structure is replaced with the optical fiber 9, it is preferable that at least one of the bundled cords is replaced with the optical fiber 9. For example, as shown in FIG. 4, in the bead portion 5, a plurality of bead cords 51 a of the bead core 51 are bundled, and the periphery thereof is wound in a ring shape in a form covered with a sheet-like wrapping rubber 51 b. At least one of the bead cords 51a is replaced with the optical fiber 9.

  According to the pneumatic tire 1, the optical fiber 9 is normally covered with a protective elastic body (rubber or the like) around the core 91, but the optical fiber 9 is bundled together with the bead cord 51 a, The cord 51 a protects the core 91 of the optical fiber 9. For this reason, the elastic body interposed between the bead cord 51a and the core 91 can be reduced as much as possible. When the optical fiber 9 is bundled together with the bead cord 51a, distortion occurs in the entire bead cord 51a, and this distortion is transmitted to the fiber Bragg grating 92 of the optical fiber 9. Here, when there are many elastic bodies interposed between the bead cord 51a and the core 91, when the strain generated in the entire bead cord 51a is transmitted to the fiber Bragg grating 92 via the elastic body, There is a possibility that the detection accuracy is lowered due to a time delay in the transmission of the distortion. In this respect, when the elastic body is small, the distortion generated in the entire bead cord 51a is easily transmitted directly to the fiber Bragg grating 92, and no time delay occurs in the transmission of the distortion to the fiber Bragg grating 92. As a result, detection accuracy can be improved.

  Further, in the pneumatic tire 1 in which at least one of the cords of the structure is replaced with the optical fiber 9, the cord is composed of a twisted cord in which a plurality of cords are twisted, and at least one of the twisted cords is attached to the optical fiber 9. It is preferably substituted. For example, as shown in FIG. 5, in the twisted cord 10 in which a plurality of cords 10 a are twisted, the central cord surrounded by the cord 10 a is replaced with an optical fiber 9.

  According to the pneumatic tire 1, each surrounding cord 10 a protects the core 91 of the optical fiber 9, so that the elastic body interposed between the cord 10 a and the core 91 can be reduced as much as possible. For this reason, the distortion generated in the entire twisted cord 10 is easily transmitted directly to the fiber Bragg grating 92 of the optical fiber 9, and no time delay occurs in the transmission of the distortion to the fiber Bragg grating 92. As a result, detection accuracy can be improved.

  Further, in the pneumatic tire 1 of the present embodiment, as shown in FIG. 2, the optical fiber 9 is disposed along the tire circumferential direction, the tire width direction, or the bias direction inside the tread rubber 20 forming the tread portion 2. Has been.

  According to the pneumatic tire 1, it is possible to detect a strain or a change in temperature of the tread rubber 20 in the tire circumferential direction, the tire width direction, or the bias direction.

  In particular, as shown in FIG. 1, the tread rubber 20 has a two-layer structure in which a tread rubber layer 20a covering the belt reinforcing layer 8 and a tread rubber layer 20b forming a tread surface 21 are laminated in different directions in the tire radial direction. In some cases, it becomes possible to detect the distortion and temperature change of each tread rubber layer 20a, 20b.

  When the tread rubber 20 has a two-layer structure of the red rubber layer 20a and the tread rubber layer 20b, it is conceivable that the optical fiber 9 is arranged as follows, although it is not clearly shown in the drawing. For example, meandering in the tire radial direction so that the fiber Bragg grating 92 is positioned in each tread rubber layer 20a, 20b while extending one optical fiber 9 in the tire circumferential direction, the tire width direction, or the bias direction. Let them be arranged. Further, for example, a plurality of optical fibers 9 are alternately arranged in the tire width direction on the tread rubber layers 20a and 20b while extending in the tire circumferential direction. Further, for example, a plurality of optical fibers 9 are alternately arranged in the tire circumferential direction on each of the tread rubber layers 20a and 20b while extending in the tire width direction. Also, for example, a plurality of optical fibers 9 are alternately arranged in the tire circumferential direction or the tire width direction on each of the tread rubber layers 20a and 20b while extending in the bias direction. By disposing the optical fiber 9 in this manner, the tread rubber layers 20a and 20b are separately detected for detecting strain and temperature changes, and the tread portion 2 is detected for strain and temperature changes in the tire radial direction. It becomes possible to do.

  Further, in the pneumatic tire 1 in which the optical fiber 9 is disposed in the tread rubber 20 along the tire circumferential direction, the tire width direction, or the bias direction, the fiber Bragg grating 92 is provided directly below the groove provided in the tread portion 2. The optical fiber 9 is preferably disposed inside the tread rubber 20 so as to be positioned. For example, in FIG. 1, the optical fiber 9 is disposed along the extending direction of the main groove 22 immediately below the main groove 22. Although not clearly shown in the drawing, the optical fiber 9 may be disposed along the extending direction of the lug groove 24 or the projection groove 25 directly below the lug groove 24 or the projection groove 25 in addition to the main groove 22. .

  The tread rubber 20 directly below the groove is often distorted even in the tread portion 2. For this reason, it is useful to detect the distortion of the tread rubber 20 and a change in temperature to dispose the optical fiber 9 directly below the groove along the extending direction of the groove.

  When the optical fiber 9 is arranged so that the fiber Bragg grating 92 is positioned immediately below the groove, the optical fiber 9 is meandered along the extending direction of the groove so that the fiber Bragg grating 92 is also positioned around the groove. 9 is preferably arranged. As a result, it becomes possible to detect distortion around the groove and a change in temperature.

  Further, in the pneumatic tire 1 in which the optical fiber 9 is disposed inside the tread rubber 20 along the tire circumferential direction, the tire width direction, or the bias direction, as shown in FIG. It is preferable that the land portion 23 is formed and the optical fiber 9 is arranged along the uneven shape formed by the main groove 22 and the land portion 23. In addition, the optical fiber 9 may be arranged along the concavo-convex shape formed by the lug groove 24 or the protruding groove 25 and the land portion 23 without being limited to the main groove 22. In this case, the fiber Bragg grating 92 is located on the convex portion that is the position of the land portion 23.

  According to such a pneumatic tire, it becomes possible to detect distortion of the land portion 23 and a change in temperature when the vehicle equipped with the pneumatic tire 1 is driven or braked.

  Further, in the pneumatic tire 1 of the present embodiment, as shown in FIG. 1, an optical fiber 9 is arranged inside the rubber forming the shoulder portion 3 along the tire circumferential direction, the tire radial direction, or the bias direction. Yes.

  According to the pneumatic tire 1, it becomes possible to detect a distortion or a change in temperature of the rubber forming the shoulder portion 3 in the tire circumferential direction, the tire radial direction, or the bias direction.

  Further, in the pneumatic tire 1 of the present embodiment, as shown in FIG. 1, an optical fiber 9 is disposed along the tire circumferential direction, the tire radial direction, or the bias direction inside the rubber forming the sidewall portion 4. ing.

  According to such a pneumatic tire 1, it becomes possible to detect distortion or temperature change of the rubber forming the sidewall portion 4 in the tire circumferential direction, the tire radial direction, or the bias direction.

  Moreover, in the pneumatic tire 1 of this Embodiment, as shown in FIG. 1, the optical fiber 9 is arrange | positioned along the tire circumferential direction inside the rubber | gum (bead filler rubber) which makes the bead part 5. As shown in FIG.

  According to the pneumatic tire 1, it is possible to detect distortion of the rubber forming the bead portion 5 in the tire circumferential direction and a change in temperature.

  As described above, the pneumatic tire according to the present invention is suitable for detecting the distortion of each place constituting the pneumatic tire according to the situation and purpose.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 20 Tread rubber 20a, 20b Tread rubber layer 21 Tread surface 22 Main groove 23 Land part 24 Lug groove 25 Projection groove 3 Shoulder part 4 Side wall part 5 Bead part 51 Bead core 51a Bead cord 51b Wrapping rubber 52 Bead filler 6 Carcass layer 7 (71, 72) Belt layer 8 (81, 82) Belt reinforcing layer 9 Optical fiber 91 Core 92 Fiber Bragg grating (diffraction grating part)
10 Twisted cord 10a Cord C Tire equator surface (tire equator line)

Claims (10)

In a pneumatic tire in which an optical fiber formed with a diffraction grating part in which the reflection wavelength of light changes due to expansion and contraction is embedded,
A pneumatic tire characterized in that, for a structure having a plurality of cords, at least one of the cords is replaced with the optical fiber.   The pneumatic tire according to claim 1, wherein at least one of the plurality of cords bundled is disposed in the optical fiber.   2. The pneumatic tire according to claim 1, wherein the cord is formed of a twisted cord in which a plurality of cords are twisted, and at least one of the twisted cords is replaced with the optical fiber. In a pneumatic tire in which an optical fiber formed with a diffraction grating part in which the reflection wavelength of light changes due to expansion and contraction is embedded,
A pneumatic tire characterized in that the optical fiber is disposed along a tire circumferential direction, a tire width direction, or a bias direction inside a tread rubber forming a tread portion.   The pneumatic tire according to claim 4, wherein the tread rubber is formed by laminating different types of tread rubber layers in a tire radial direction, and the optical fiber is disposed in each tread rubber.   The pneumatic tire according to claim 4, wherein the optical fiber is arranged along the extending direction of the groove immediately below the groove provided in the tread portion.   The pneumatic tire according to claim 4, wherein a land portion is formed by a groove provided in the tread portion, and the optical fiber is arranged along an uneven shape formed by the groove and the land portion. In a pneumatic tire in which an optical fiber formed with a diffraction grating part in which the reflection wavelength of light changes due to expansion and contraction is embedded,
A pneumatic tire characterized in that the optical fiber is disposed along a tire circumferential direction, a tire radial direction, or a bias direction inside a rubber forming a shoulder portion. In a pneumatic tire in which an optical fiber formed with a diffraction grating part in which the reflection wavelength of light changes due to expansion and contraction is embedded,
A pneumatic tire, characterized in that the optical fiber is disposed along a tire circumferential direction, a tire radial direction, or a bias direction inside rubber forming a sidewall portion. In a pneumatic tire in which an optical fiber formed with a diffraction grating part in which the reflection wavelength of light changes due to expansion and contraction is embedded,
A pneumatic tire characterized in that the optical fiber is arranged along the tire circumferential direction inside rubber forming a bead portion.

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