Tire with functional component

Abstract

To provide a tire with a functional component which has excellent sensing accuracy of a sensor function included in the functional component provided on a tire inner surface of a tread part.SOLUTION: A tire with a functional component includes: a tread part extending in a tire circumferential direction and forming an annular form; a pair of side wall parts disposed at both sides of the tread part; and a pair of bead parts disposed at the inner side in a tire radial direction of the pair of side wall parts, and has: at least one carcass layer installed between the pair of bead parts; and a belt layer which is disposed at the outer periphery side of the carcass layer in the tread part and in which a plurality of steel cords are buried in parallel to each other on one surface. The tire includes a storage body containing a functional component on a tire inner surface of the tread part. The functional component has a contact surface which contacts with the tire inner surface; and a sensor function configured to detect tire information. A total thickness (Gb) of the belt layer is thinner than 2.3 mm.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tire provided with a functional component having a sensor function for detecting tire information on the inner surface of the tire.

Background Art

[0002] In order to detect tire information, functional components having a sensor function (such as electronic components such as sensor units) are disposed on the tire. In particular, due to ease of detecting air pressure and wear, such functional components are disposed on the inner surface of the tread portion of the tire (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, the functional components disposed on the inner surface of the tread portion of the tire are difficult to stabilize the sensing accuracy of the sensor function due to the influence of tire rotation during driving, etc., and there is room for further improvement.

[0005] Therefore, an object of the present invention is to provide a tire with a functional component having excellent sensing accuracy of the sensor function of the functional component provided on the inner surface of the tread portion of the tire.

Means for Solving the Problems

[0006] To solve the above problems, the present inventor has intensively studied and has a tire comprising a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the inner side in the tire radial direction of the pair of sidewall portions, at least one carcass layer mounted between the pair of bead portions, and a belt layer disposed on the outer peripheral side of the carcass layer in the tread portion, in which a plurality of steel cords are embedded in parallel on one surface. The tire is provided with a housing that houses functional components on the inner surface of the tread portion of the tire. The functional components have at least a contact surface that contacts the inner surface of the tire and a sensor function for detecting tire information. The inventors have found that a tire in which the total thickness (Gb) of the belt layer is less than 2.3 mm has excellent sensing accuracy of the sensor function of the functional components, and thus completed the present invention.

[0007] That is, the present invention is as follows <1> to <7>. <1>A tire comprising a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the inner side in the tire radial direction of the pair of sidewall portions, at least one carcass layer mounted between the pair of bead portions, and a belt layer disposed on the outer peripheral side of the carcass layer in the tread portion, in which a plurality of steel cords are embedded in parallel on one surface, the tire being provided with a housing that houses functional components on the inner surface of the tread portion of the tire, the functional components having at least a contact surface that contacts the inner surface of the tire and a sensor function for detecting tire information, the total thickness (Gb) of the belt layer being less than 2.3 mm. <2>The tire according to <1>, wherein the acetone extraction amount of the belt layer is 9.0 parts by mass or more with respect to 100 parts by mass of the rubber component constituting the belt layer. <3>The container has a sheet-like base portion with one surface joined to the inner surface of the tire, and a side wall protruding from the surface of the base portion opposite to the surface joined to the inner surface of the tire, and includes a housing portion for housing the functional component such that the side wall surrounds the functional component. The tire according to <1> or <2>, wherein a crown gauge (Gc), which is the thickness of the side wall at the midpoint of the straight-line distance from the surface of the base portion joined to the inner surface of the tire to the protruding end of the side wall, and the Gb satisfy the relationship of the following formula (1). (1) Gc ≦ -0.30Gb + 4.2 <4>The tire according to any one of <1> to <3>, including two belt layers, wherein a belt angle formed by the steel cords embedded in the two belt layers is 22 degrees or more. <5>The tire according to any one of <1> to <4>, wherein the container is fixed to the inner surface of the tire. <6>The tire according to <5>, wherein the container is fixed to the inner surface of the tire by an adhesive. <7>The tire according to any one of <1> to <6>, wherein the sensor function of the functional component is a sensor function using a piezoelectric element as a sensor element.

Advantages of the Invention

[0008] According to the present invention, a tire with a functional component can be obtained in which the sensing accuracy of the sensor function of the functional component provided on the inner surface of the tire in the tread portion is excellent.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0010] The present invention will be described. The present invention includes a tread portion that extends in the tire circumferential direction and forms an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the inner side in the tire radial direction of the pair of sidewall portions. It has at least one carcass layer mounted between the pair of bead portions, and a belt layer in which a plurality of steel cords are embedded in parallel on one surface and disposed on the outer peripheral side of the carcass layer in the tread portion. The tire is provided with a container in which functional components are housed on the inner surface of the tire in the tread portion. The functional components have at least a contact surface that contacts the inner surface of the tire and a sensor function for detecting tire information. The tire is such that the total thickness (Gb) of the belt layer is less than 2.3 mm. Hereinafter, this will also be referred to as "the tire of the present invention".

[0011] In the present invention, the numerical range represented by "~" means a numerical range in which the numerical value described before "~" is the lower limit value and the numerical value described after "~" is the upper limit value, unless otherwise specified.

[0012] Hereinafter, the configuration of the tire (main body) of the present invention, the configuration of the container provided in the tire of the present invention, etc. will be described in detail with reference to the drawings. Note that the dimensional ratios (length, thickness, etc.), orientations, etc. of each member shown in the drawings may be different from the actual dimensional ratios, orientations, etc. in order to facilitate understanding of the invention. Also, in some cases, some reference numerals etc. may be omitted.

[0013] [Tire] The tire body of the present invention includes, for example, a tread portion 1 that extends in the tire circumferential direction and forms an annular shape as shown in the embodiment of FIG. 1, a pair of sidewall portions 2, 2 disposed on both sides of the tread portion 1 (both ends in the tire width direction), and a pair of bead portions 3, 3 disposed on the inner side in the tire radial direction of the pair of sidewall portions 2, 2. It further includes at least one carcass layer 4 mounted between the pair of bead portions 3, 3, and a belt layer 7 disposed on the outer peripheral side of the carcass layer 4 in the tread portion 1, in which a plurality of steel cords are embedded in parallel on one surface.

[0014] In this embodiment, the carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded from the inner side to the outer side of the tire around the bead core 5 disposed in each bead portion 3. A bead filler 6 made of a rubber composition having a triangular cross-section is disposed on the outer periphery of the bead core 5.

[0015] Also, as described above, one or more (preferably a plurality of) belt layers 7 are disposed on the outer peripheral side of the carcass layer 4 in the tread portion 1. These belt layers 7 include a plurality of steel cords (a plurality of steel cords embedded in parallel on one surface) that are inclined in substantially the same direction with respect to the tire circumferential direction, and when including a plurality (for example, two layers) of belt layers 7, the steel cords are arranged so as to cross each other between these layers. In the belt layer 7, the inclination angle of the steel cord with respect to the tire circumferential direction is set, for example, in the range of 10° to 60° at the smaller angle. On the outer peripheral side of the belt layer 7, for the purpose of improving high-speed durability, at least one belt cover layer 8 in which reinforcing cords are arranged at an angle of, for example, 5° or less with respect to the tire circumferential direction may be disposed. As the reinforcing cords of the belt cover layer 8, organic fiber cords such as nylon and aramid are preferably used.

[0016] Here, when it is said that a plurality of steel cords are "embedded parallel to one surface" in the belt layer 7, it means that the center lines passing through the centers of the circumscribed circles in the radial direction of each of the plurality of steel cords included in the belt layer 7 are arranged on substantially the same plane and are substantially parallel to each other (oriented in substantially the same direction) within the layer. Note that the structure of each steel cord has a twisted structure composed of one or a plurality of strands (steel wire strands).

[0017] Furthermore, a tread rubber layer 15 is disposed in the tread portion 1. The tread rubber layer 15 includes at least a cap tread rubber layer 15A. In this embodiment, it is composed of two layers, namely, the cap tread rubber layer 15A forming the tread surface of the tread portion 1 and the under tread rubber layer 15B located on the inner side in the tire radial direction of the cap tread rubber layer 15A. Note that the tread rubber layer 15 may include a ground tread made of conductive rubber exposed on the tire contact surface and wing tips respectively disposed at both ends in the tire width direction of the cap tread rubber layer 15A.

[0018] The constituent components of the tire of the present invention (components constituting each member such as the tread portion 1 and each layer such as the belt layer 7) are not particularly limited, and known components for constituting a tire such as rubber components can be arbitrarily used. However, at least the tread portion 1 and the belt layer 7 of the tire of the present invention contain a rubber component.

[0019] And in the tire of the present invention, the total thickness (Gb) of the belt layer 7 described above is less than 2.3 mm. Thereby, the sensing accuracy of the sensor function of the functional component accommodated in the container provided on the inner surface of the tire in the tread portion 1 becomes excellent. Note that it is more preferable that the total thickness (Gb) of this belt layer 7 is 2.2 mm or less. This lower limit may be 0.5 mm or more, or may be 1.0 mm or more.

[0020] Here, the "total thickness of the belt layer (total gauge, Gb)" means the thickness of one layer (the distance between both main surfaces) when the belt layer 7 has one layer, and when the belt layer 7 has two or more layers, it means the sum of the distances (Gx) between the planes in which the center lines passing through the centers of the radially circumscribed circles of the plurality of steel cords embedded in each layer are arranged, plus the value obtained by taking half of each of the two Gx values arranged on the outermost side of the belt layer 7 (the belt layer 7 with a laminated structure) among these distances between the planes. That is, when the belt layer 7 has two or more layers, the value calculated as described above is made equivalent to the distance between both main surfaces (the outer surfaces of the belt layer 7 with a laminated structure). For example, when the belt layer 7 has two layers as shown in FIG. 4, the thickness (G1 + G1×1 / 2 + G1×1 / 2) obtained by adding the value obtained by taking half of each of the two outermost (i.e., G1) of the distances (G1) between the planes (LF1 and LF2) in which the center lines passing through the centers of the radially circumscribed circles of the plurality of steel cords embedded in these two layers are arranged is the Gb of this two-layer structure. Also, when the belt layer 7 has four layers as shown in FIG. 5, the thickness (G1 + G2 + G3 + G1×1 / 2 + G3×1 / 2) obtained by adding the sum of the distances (G1, G2, and G3) between the planes (LF1, LF2, LF3, and LF4) in which the center lines passing through the centers of the radially circumscribed circles of the plurality of steel cords embedded in these four layers are arranged, plus the value obtained by taking half of each of the two outermost (i.e., G1 and G3) of the distances between the planes is the Gb of this four-layer structure. And this thickness, the distance between the planes, etc. are the average values measured at arbitrary 10 locations. In FIGS. 4 and 5, for ease of understanding, the directions of the steel cords are all made the same.

[0021] Furthermore, since the rigidity of the belt layer 7 is more likely to decrease and the sensing accuracy of the sensor function of the functional component is more excellent, it is more preferable that the acetone extraction amount of the belt layer 7 is 9.0 parts by mass or more with respect to 100 parts by mass of the rubber component constituting the belt layer 7. And it is even more preferable that this acetone extraction amount is 10.0 parts by mass or more with respect to 100 parts by mass of the rubber component constituting the belt layer 7.

[0022] Here, the "acetone extraction amount" of the belt layer 7 means that for a rubber test piece cut out from the belt layer 7 (a rubber test piece cut out from the area surrounding the steel cord 9 of the belt layer 7, that is, a rubber test piece not including the steel cord), in accordance with JIS K 6229:2015, the measurement of the acetone extraction amount is carried out under the conditions of 20 °C and atmospheric pressure for 8 hours of extraction time, and the mass reduced by extraction is shown as the ratio (mass ratio) to the amount of the rubber component (converted to 100 parts by mass) contained in this rubber test piece. And this acetone extraction amount means the average value obtained by collecting the above rubber test pieces from any three locations and performing the above measurement, regardless of whether the belt layer 7 is one layer or two or more layers.

[0023] Also, in the case of a configuration including two belt layers 7, since the rigidity of this belt layer 7 is more likely to decrease and the sensing accuracy of the sensor function of the functional component is more excellent, it is more preferable that the belt angle formed by the steel cords 9 embedded in the two belt layers 7 is 22 degrees or more. That is, in the two belt layers 7, it is more preferable that the belt angle formed by the direction in which the steel cord 9 embedded in one layer faces and the direction in which the steel cord 9 embedded in the other layer faces is 22 degrees or more. And this belt angle is more preferably 23 degrees or more. This upper limit may be 40 degrees or less, and may also be 35 degrees or less.

[0024] Here, this "belt angle" is the value obtained by dividing by 2 the angle formed by the respective steel cords 9 embedded in the two belt layers 7 (the angle formed by the substantially same directions in which the plurality of steel cords embedded in each belt layer 7 face).

[0025] The size and application of the tire of the present invention are not particularly limited, and it is possible to use various tires such as passenger car tires, truck bus tires, and off-road tires.

[0026] Incidentally, the tire of the present invention is preferably a pneumatic tire. As the gas filled in this pneumatic tire, for example, air, nitrogen, argon, an inert gas such as helium, and other gases can be used.

[0027] [Container] The tire of the present invention is provided with a container 30 on the inner surface 12 of the tire tread portion 1 of the tire in the above-described embodiment. The arrangement position of this container 30 is not particularly limited as long as it is the inner surface 12 of the tread portion 1, and it may be a position that does not pass through the center point in the tire width direction on the inner surface 12 of the tread portion 1.

[0028] The container 30 provided in the tire of the present invention is composed of a rubber component. And this container is provided on the inner surface 12 of the tread portion 1 of the tire, and houses a functional component 20 having a sensor function for detecting tire information so as to have a contact surface 21 that contacts this inner surface 12 of the tire. For example, as shown in FIGS. 1 to 3, the base 31 of the container 30 is joined and fixed to the inner surface 12 of the tread portion 1 of the tire (the inner surface 12 joined to the base 31 is omitted in FIGS. 2 and 3), and the housing portion 33 houses the functional component 20 so as to surround it with the side wall 32. Further, an embodiment is shown in which the housed functional component 20 has a contact surface 21 that contacts the inner surface 12 of the tread portion 1 via the base 31.

[0029] Here, when it is said that the container is "provided on the inner surface of the tire of the tread portion", it means that the container 30 is connected and arranged on the inner surface 12 of the tire of the tread portion 1 (the inner peripheral surface of the tire located at a position facing the tread surface of the tread portion). Also, when it is said that the functional component has a contact surface "in contact with the inner surface of the tire (of the tread portion)", it includes not only the embodiment in which the functional component 20 has a contact surface 21 that directly contacts the inner surface 12 of the tire of the tread portion 1, but also the embodiment in which the functional component 20 contacts through a member (the base portion 31 in the embodiment shown in FIG. 3) that is in surface contact with the inner surface 12 of the tire of the tread portion 1 in the container 30. That is, the embodiment in which the functional component 20 is in direct surface contact with the inner surface 12 of the tire of the tread portion 1, and the embodiment in which the functional component 20 is in surface contact through a member that is in surface contact with the inner surface 12 of the tire of the tread portion 1 in the container 30 are included.

[0030] And it is more preferable that the container 30 in which this functional component 20 is accommodated is fixed to the inner surface 12 of the tire of the tread portion 1 (in a state where the position of the container 30 does not substantially change), and further, it is more preferable that this is an embodiment in which the container 30 is fixed to the inner surface 12 of the tire of the tread portion 1 by an adhesive. As this adhesive, an epoxy-based adhesive, an acrylic-based adhesive, or the like can be used. Also, a double-sided tape or the like may be used as the adhesive.

[0031] Incidentally, as described above, the container 30 provided in the tire of the present invention is composed of a rubber component, but may further contain components other than the rubber component as optional components within a range that does not significantly affect the effects of the present invention. For example, carbon black, white fillers (such as silica, talc, mica, clay, calcium carbonate, etc.), resin components (such as terpene resin, coumarone resin, indene resin, rosin resin, etc.), zinc oxide (zinc white), oil (such as aroma oil), stearic acid, wax, lecithin, anti-aging agent, plasticizer, vulcanizing agent, vulcanization accelerator, vulcanization accelerator auxiliary agent, and other various additives commonly used in rubber products can be contained in an appropriate amount. As the vulcanizing agent, sulfur is typically exemplified, but as a component other than sulfur, a compound having a cross-linking function between polymers such as peroxide may also be used. Further, these may be used in combination.

[0032] And since the restraining force of the functional parts by the container decreases and the noise level further decreases, and the effects of the present invention are more easily exhibited, this container 30 has a sheet-like base portion 31 having one surface joined to the tire inner surface 12 of the tread portion 1 as shown in FIG. 2, FIG. 3, or FIG. 6, and a side wall 32 protruding from the surface opposite to the surface joined to the tire inner surface 12 of the base portion 31, and includes a housing portion 33 that houses the functional parts 20 so that the side wall 32 surrounds them. It is more preferable that the crown gauge (Gc), which is the thickness of the side wall 32 at the midpoint (D1 / 2) of the linear distance (D, that is, the shortest linear distance from the joining surface at the protruding end) from the surface joined to the tire inner surface 12 of the base portion 31 to the protruding end of the side wall 32 (the end with the longest shortest linear distance from this joining surface), and the total thickness (Gb) of the above-described belt layer 7 satisfy the relationship of the following formula (1). (1) Gc ≦ -0.30Gb + 4.2

[0033] Furthermore, since the above effects are more likely to be exerted, this crown gauge (Gc) preferably has a value of -0.30Gb + 4.0 or less. That is, it is more preferable that the above formula (1) is Gc ≦ -0.30Gb + 4.0. This lower limit may be Gc > -0.30Gb + 1.0, or may be Gc > -0.30Gb + 1.5.

[0034] The specific thickness of this crown gauge (Gc) is not limited, but from the viewpoints of making it difficult to reduce the productivity and durability of the container and maintaining the accommodation capacity of the functional parts, etc., it is more preferably 1.00 mm or more, even more preferably 1.60 mm or more, even more preferably 2.10 mm or more, and even more preferably 2.50 mm or more. The upper limit may be 4.50 mm or less, may be 3.90 mm or less, or may be 3.50 mm or less.

[0035] [Functional parts] The functional part 20 accommodated in the container of the tire of the present invention is not limited as long as it has a sensor function for detecting tire information and can have a contact surface 21 that contacts the inner surface 12 of the tread part 1 of the tire. For example, electronic parts including various sensors, transmitters, receivers, control circuits, batteries, etc. are exemplified. Examples of the tire information detected and acquired by the sensor function include the internal temperature and internal pressure (air pressure) of the pneumatic tire, the wear amount of the tread part, etc. A temperature sensor or a pressure sensor can be used for measuring the internal temperature and internal pressure. For detecting the wear amount of the tread part, a sensor element using a piezoelectric element is disposed on the contact surface, and a functional part 20 that detects an output voltage corresponding to the tire deformation during running by the sensor element and detects the wear amount of the tread part based on the output voltage is preferably exemplified. That is, from the viewpoint of detecting the wear amount of the tread part 1, it is more preferable that the sensor function of this functional part 20 is a sensor function using a piezoelectric element as the sensor element. In addition, it is also possible to use an acceleration sensor or a magnetic sensor.

[0036] The tire of the present invention (tire with functional components) having the above-described configuration has excellent sensing accuracy of the sensor function of the functional components provided on the inner surface of the tread portion of the tire.

[0037] Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments, and various modifications are possible within the technical idea of the present invention.

Embodiment

[0038] (Manufacture and evaluation of tire with functional components) A tire having a size of 235 / 55R20 102V, which has a configuration as shown in FIG. 1 and includes a two-layer belt layer in which a plurality of steel cords are embedded parallel to one surface, the total thickness (Gb) of the belt layer, the acetone extraction amount of the belt layer (mass ratio of the acetone extraction amount to 100 parts by mass of the rubber component constituting the belt layer), and the belt angle of the steel cords embedded in the two-layer belt layer are the values shown in Table 1 below. A container having a shape as shown in FIGS. 2 to 3 and a crown gauge (Gc) of the side wall of the accommodating portion being the value shown in Table 1 below is bonded and fixed to the inner surface of the tread portion of the tire shown in FIG. 1 with an adhesive. Further, a functional component using a piezoelectric element as a sensor element is mounted on the container so that the piezoelectric element is disposed on the contact surface that contacts the inner surface of the tire, and tires with various functional components are manufactured.

[0039] Then, for the obtained tires with functional components of Comparative Examples 1 to 4 and Examples 1 to 5, the sensing accuracy of the functional components was evaluated as follows.

[0040] <Sensing accuracy> For each tire with functional components, it was assembled on a wheel with an air pressure of 230 kPa and run on a drum at a speed of 30 km / h by a drum tester, and the CV value (N = 10) of the peak height of the waveform detected by the sensor element of the functional component was measured. The results are shown in the lower part of Table 1 below. The results are expressed as an index with the value of Comparative Example 1 being 100.

[0041]

Table 1

[0042] From these results, in Examples 1 to 5 where the total thickness (Gb) of the belt layer of the tire was 2.20 mm or less, the sensing accuracy of the above functional components was excellent. On the other hand, in Comparative Examples 1 to 4 where the total thickness (Gb) of the belt layer of the tire was 2.35 mm or more, the sensing accuracy of the above functional components was degraded.

Explanation of Signs

[0043] 100 Tire 1 Tread portion 2 Sidewall portion 3 Bead portion 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 8 Belt cover layer 9 Steel cord 11 Tire circumferential groove 12 Inner surface of the tread portion of the tire 20 Functional component 21 Contact surface (piezoelectric element) 30 Container 31 Base portion 32 Sidewall 33 Accommodating portion

Claims

1. A tire having a tread portion extending in the 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 on the inner side in the tire radial direction of the pair of sidewall portions, the tire comprising at least one carcass layer mounted between the pair of bead portions, and a belt layer disposed on the outer peripheral side of the carcass layer in the tread portion, in which a plurality of steel cords are embedded in parallel on one surface, the tread portion having a container for housing functional components on the inner surface of the tire, the functional components having at least a contact surface that contacts the inner surface of the tire and a sensor function for detecting tire information, the tire having a total thickness (Gb) of the belt layer of less than 2.3 mm.

2. The tire according to claim 1, wherein the acetone extraction amount of the belt layer is 9.0 parts by mass or more with respect to 100 parts by mass of the rubber component constituting the belt layer.

3. The container includes a sheet-like base portion having one surface joined to the inner surface of the tire, and a side wall protruding from the surface of the base portion opposite to the surface joined to the inner surface of the tire, the container having a housing portion for housing the functional components so that the side wall surrounds the functional components, the tire according to claim 1 or 2, wherein a crown gauge (Gc), which is the thickness of the side wall at the midpoint of the straight-line distance from the surface of the base portion joined to the inner surface of the tire to the protruding end of the side wall, and the Gb satisfy the relationship of the following formula (1). (1) Gc ≦ -0.30Gb + 4.2

4. The tire according to claim 1 or 2, including two belt layers, the belt angle formed by the steel cords embedded in the two belt layers being 22 degrees or more.

5. The tire according to claim 1 or 2, wherein the container is fixed to the inner surface of the tire.

6. The tire according to claim 5, wherein the container is fixed to the inner surface of the tire by an adhesive.

7. The tire according to claim 1 or 2, wherein the sensor function of the functional components is a sensor function using a piezoelectric element as a sensor element.

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