tire

Abstract

To provide a tire which is mounted with a sensor capable of measuring a pressure distribution.SOLUTION: A tire is a tire for a movable body, wherein a sensor 1 is provided inside the tire, the sensor has an insulation layer, a plurality of first resistance parts 31 arranged side by side with a longitudinal direction facing a first direction on one side of the insulation layer, a plurality of second resistance parts 32 arranged side by side with a longitudinal direction facing a second direction crossing the first direction on the other side of the insulation layer, and a pair of electrodes 41 and 42 provided on both ends of each of the first resistance parts and each of the second resistance parts, when the first resistance parts and / or the second resistance parts are pressed, the resistance values continuously change according to a magnitude of a pressure to which resistance values between the pair of electrodes of the pressed first resistance parts and / or second resistance parts are applied.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a tire equipped with a sensor. [Background technology]

[0002] The air pressure of automobile tires changes with temperature, and when the tires are warm, they expand and the air pressure increases, and when the temperature drops, the air pressure decreases, so it is difficult to measure the air pressure in real time. In addition, the air pressure of tires is generally measured using an air pressure gauge, which is a time-consuming and labor-intensive task, which is problematic.

[0003] There are also known valves with air pressure sensors that can check air pressure even while driving, but these only detect the pressure at the specific location where the valve is located, making it difficult to grasp the pressure distribution over the entire tire.

[0004] Tires on automobiles and other vehicles can wear unevenly if the vehicle is going too fast around a corner or if there is an abnormality such as poor air pressure. Driving with unevenly worn tires is extremely dangerous as it can cause the tire to burst or the steering wheel to be pulled out, resulting in an accident.

[0005] From the above-mentioned points, measuring the pressure distribution on tires is extremely important for the safe running of automobiles, etc. For this reason, a method has been proposed for measuring the deformation state of a tire by attaching deformation detection elements to the inner surface, the outer surface, and the reinforcing layer of the tire (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2008-249567 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, conventional measurement methods can only detect partial deformation of the tire, making it difficult to measure the pressure distribution acting on the tire.

[0008] The present invention has been made in consideration of the above-mentioned points, and has an object to provide a tire equipped with a sensor capable of measuring pressure distribution. [Means for solving the problem]

[0009] The tire is a tire for a moving body, and a sensor is provided on the inside of the tire. The sensor has an insulating layer, a plurality of first resistor portions arranged side by side on one side of the insulating layer with their longitudinal directions facing a first direction, a plurality of second resistor portions arranged side by side on the other side of the insulating layer with their longitudinal directions facing a second direction intersecting the first direction, and a pair of electrodes provided at both ends of each of the first resistor portions and each of the second resistor portions, The first resistor portion and the second resistor portion are made of Cr, CrN, and Cr 2 The first resistor portion and the second resistor portion are formed of a film containing N, and the first resistor portion and the second resistor portion are formed of CrN and Cr 2 The ratio of N is 20% by weight or less, and the CrN and Cr 2 The Cr in N 2 The proportion of N is 80% by weight or more and less than 90% by weight, When the first resistance portion and / or the second resistance portion is pressed, the resistance value between the pair of electrodes of the pressed first resistance portion and / or the pressed second resistance portion changes continuously depending on the magnitude of the applied pressure. Effect of the Invention

[0010] According to the disclosed technology, it is possible to provide a tire equipped with a sensor capable of measuring pressure distribution. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view (part 1) illustrating a tire according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view (part 2) illustrating the tire according to the first embodiment. [Diagram 3] FIG. 2 is a plan view illustrating the sensor according to the first embodiment. [Figure 4] FIG. 2 is a cross-sectional view (part 1) illustrating the sensor according to the first embodiment. [Diagram 5] FIG. 4 is a second cross-sectional view illustrating the sensor according to the first embodiment. [Figure 6] 1 is a block diagram illustrating a pressure distribution detection device according to a first embodiment. [Figure 7] 3 is a block diagram illustrating a control device of the pressure distribution detection device according to the first embodiment. FIG. [Figure 8] 1 is a cross-sectional view illustrating a sensor according to a first modified example of the first embodiment. FIG. [Figure 9] 11 is a cross-sectional view illustrating a sensor according to a second modified example of the first embodiment. FIG. [Figure 10] 11 is a plan view illustrating a sensor according to a third modified example of the first embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and duplicated explanations may be omitted.

[0013] First Embodiment Fig. 1 is a cross-sectional view (part 1) illustrating a tire according to the first embodiment, showing a cross-section of the tire in the width direction. Fig. 2 is a cross-sectional view (part 2) illustrating a tire according to the first embodiment, showing a cross-section of the tire cut in the direction perpendicular to the width direction at the center in the width direction. Note that Fig. 2 is on a different scale from Fig. 1, and some of the components shown in Fig. 1 are omitted.

[0014] 1 and 2, the tire 100 has a tread portion 110, left and right sidewall portions 120, and left and right bead portions 130. The tread portion 110 is the portion of the tire 100 that comes into contact with the road surface. The sidewall portions 120 are the portions that form the side surfaces of the tire 100. The bead portions 130 are the portions that fix the tire 100 to the rim of a wheel.

[0015] An inner liner 140 is provided on the inside of the tire 100. The inner liner 140 is, for example, a layer made of rubber. On the outside of the inner liner 140, a carcass 150 is provided, which passes through the tread portion 110 and the left and right sidewall portions 120 and extends between the left and right bead portions 130. The carcass 150 is, for example, a layer in which fibers or steel are covered with rubber. Both ends of the carcass 150 are folded back so as to sandwich the bead cores 160 and the bead fillers 170. A plurality of belts 180 are provided on the outer circumferential side of the carcass 150 of the tread portion 110.

[0016] The sensor 1 is attached to the inner circumferential side of the inner liner 140 (the side closer to the center of the tire 100). The sensor 1 is preferably attached to the entire width direction and the entire circumferential direction of the inner circumferential side of the inner liner 140. Note that instead of attaching the sensor 1 to the inner circumferential side of the inner liner 140, the sensor 1 may be embedded in any part located inside the outermost circumference of the tire 100 (the surface in contact with the road surface). For example, the sensor 1 may be embedded in the inner liner 140.

[0017] The sensor 1 is provided to detect the pressure distribution on the tire 100 when the tire 100 is mounted on a moving body such as an automobile. The pressure on the tire 100 includes pressure from the outside of the tire 100 (pressure from the road surface) and pressure from inside the tire 100 (air pressure), and the sensor 1 can detect the combined pressure distribution. Note that a moving body refers to an object that can move and is equipped with the tire 100, such as an automobile, a motorcycle, a robot, etc.

[0018] Fig. 3 is a plan view illustrating the sensor according to the first embodiment. Fig. 4 is a cross-sectional view illustrating the sensor according to the first embodiment, showing a cross section along line AA in Fig. 3.

[0019] 3 and 4 show the state before the sensor 1 is placed on the tire 100. The X direction corresponds to the width direction of the tire 100, the Y direction corresponds to the circumferential direction of the tire 100, and the Z direction corresponds to the radial direction of the tire 100.

[0020] 3 and 4, the sensor 1 has a substrate 10, a resistor 30 (a plurality of resistance portions 31 and 32), and a plurality of terminal portions 41 and 42. The sensor 1 is disposed in the tire 100 such that the longitudinal direction (Y direction) of the juxtaposed resistance portions 31 and 32 faces the circumferential direction of the tire 100. Here, the sensor 1 is disposed such that the resistance portion 31 side faces the inner liner 140 side.

[0021] In this embodiment, for convenience, in the sensor 1, the side where the resistance portion 31 of the substrate 10 is provided is referred to as the upper side or one side, and the side where the resistance portion 32 is provided is referred to as the lower side or the other side. Also, the surface where the resistance portion 31 of each part is provided is referred to as one side or upper surface, and the surface where the resistance portion 32 is provided is referred to as the other side or lower surface. However, the sensor 1 can be used upside down or placed at any angle. Also, the planar view refers to viewing the object from the normal direction of the upper surface 10a of the substrate 10, and the planar shape refers to the shape of the object viewed from the normal direction of the upper surface 10a of the substrate 10.

[0022] The substrate 10 is an insulating member that serves as a base layer for forming the resistor 30 and the like, and has flexibility. The thickness of the substrate 10 is not particularly limited and can be appropriately selected depending on the purpose, and can be, for example, about 5 μm to 500 μm. In particular, it is preferable that the thickness of the substrate 10 is 5 μm to 200 μm, since the strain sensitivity error of the resistor portions 31 and 32 can be reduced.

[0023] The substrate 10 can be formed from an insulating resin film such as PI (polyimide) resin, epoxy resin, PEEK (polyether ether ketone) resin, PEN (polyethylene naphthalate) resin, PET (polyethylene terephthalate) resin, PPS (polyphenylene sulfide) resin, polyolefin resin, etc. The film refers to a flexible member having a thickness of about 500 μm or less.

[0024] Here, "formed from an insulating resin film" does not prevent the base material 10 from containing fillers, impurities, etc. in the insulating resin film. The base material 10 may be formed from an insulating resin film containing fillers such as silica or alumina.

[0025] Examples of materials other than resin for the substrate 10 include SiO 2 , ZrO 2 (including YSZ), Si, Si 2 N 3 , Al 2 O 3 (including sapphire), ZnO, perovskite ceramics (CaTiO 3 , BaTiO 3 ) and other crystalline materials, and furthermore, amorphous glass and the like can be used. Furthermore, metals such as aluminum, aluminum alloys (duralumin), and titanium can be used as the material of the base material 10. In this case, for example, an insulating film is formed on the metal base material 10.

[0026] The resistor 30 is formed on the substrate 10 and is a sensing part whose resistance value changes continuously in response to applied pressure. The resistor 30 may be formed directly on the upper surface 10a and the lower surface 10b of the substrate 10, or may be formed on the upper surface 10a and the lower surface 10b of the substrate 10 via another layer.

[0027] The resistor 30 includes a plurality of resistive portions 31 and 32 laminated via the substrate 10. In other words, the resistor 30 is a collective term for the plurality of resistive portions 31 and 32, and will be referred to as the resistor 30 when there is no need to particularly distinguish between the resistive portions 31 and 32. For the sake of convenience, the resistive portions 31 and 32 are shown in a matte pattern in FIG. 3.

[0028] The multiple resistance portions 31 are thin films arranged in the Y direction at predetermined intervals on the upper surface 10a of the substrate 10 with their longitudinal directions aligned in the X direction. The multiple resistance portions 32 are thin films arranged in the X direction at predetermined intervals on the lower surface 10b of the substrate 10 with their longitudinal directions aligned in the Y direction.

[0029] In this embodiment, the plurality of resistor portions 31 and the plurality of resistor portions 32 are orthogonal to each other in a plan view, but this is not limiting. In other words, the plurality of resistor portions 31 and the plurality of resistor portions 32 do not need to be orthogonal to each other in a plan view, but may intersect each other.

[0030] The resistor 30 can be made of, for example, a material containing Cr (chromium), a material containing Ni (nickel), or a material containing both Cr and Ni. That is, the resistor 30 can be made of a material containing at least one of Cr and Ni. An example of a material containing Cr is a Cr mixed phase film. An example of a material containing Ni is Cu-Ni (copper nickel). An example of a material containing both Cr and Ni is Ni-Cr (nickel chromium).

[0031] Here, the Cr mixed phase film is composed of Cr, CrN, Cr 2 It is a film containing a mixed phase of N, etc. The Cr mixed phase film may contain inevitable impurities such as chromium oxide.

[0032] The thickness of the resistor 30 is not particularly limited and can be appropriately selected depending on the purpose, and can be, for example, about 0.05 μm to 2 μm. In particular, a thickness of 0.1 μm or more is preferable in that the crystallinity of the crystals constituting the resistor 30 (for example, the crystallinity of α-Cr) is improved. Furthermore, a thickness of 1 μm or less is even more preferable in that film cracks and warping from the substrate 10 caused by internal stress of the film constituting the resistor 30 can be reduced.

[0033] The width of the resistor 30 is not particularly limited and can be appropriately selected depending on the purpose, and can be, for example, about 0.1 μm to 1000 μm (1 mm). The pitch between adjacent resistors 30 is not particularly limited and can be appropriately selected depending on the purpose, and can be, for example, about 1 mm to 100 mm. Note that, in practice, about several hundred to several tens of thousands of resistor portions 31 and 32 are provided.

[0034] For example, when the resistor 30 is a Cr mixed phase film, the temperature coefficient of the resistor 30 can be stabilized and the sensitivity of the resistor 30 to applied pressure can be improved by using α-Cr (alpha chromium), which is a stable crystal phase, as the main component. Here, the main component means that the target substance accounts for 50 mass% or more of the total substances constituting the resistor, but from the viewpoint of stabilizing the temperature coefficient of the resistor 30 and improving the sensitivity of the resistor 30 to applied pressure, the resistor 30 preferably contains α-Cr at 80 weight% or more, and more preferably contains 90 weight% or more. α-Cr is Cr with a bcc structure (body-centered cubic lattice structure).

[0035] In addition, when the resistors 31 and 32 are made of a Cr mixed phase film, the CrN and Cr 2 The N content is preferably 20% by weight or less. 2 By controlling the N content to 20% by weight or less, the decrease in the gauge factor can be suppressed.

[0036] Also, CrN and Cr 2 Cr in N 2The proportion of N is preferably 80% by weight or more and less than 90% by weight, and more preferably 90% by weight or more and less than 95% by weight. 2 Cr in N 2 The N ratio is 90% by weight or more and less than 95% by weight, so Cr has semiconducting properties. 2 The decrease in TCR (negative TCR) becomes more pronounced due to the addition of N. Furthermore, the reduction in ceramic formation reduces brittle fracture.

[0037] On the other hand, trace amounts of N 2 Or, if atomic N is mixed in or present, it will escape from the film due to the external environment (for example, a high temperature environment), causing a change in film stress.By creating chemically stable CrN, it is possible to obtain a stable strain gauge without generating the unstable N mentioned above.

[0038] The terminal portion 41 extends from both ends of each resistor portion 31 on the upper surface 10a of the base material 10, and is formed in a substantially rectangular shape wider than the resistor portion 31 in a plan view. The terminal portion 41 is a pair of electrodes for outputting a change in the resistance value of the resistor portion 31 caused by an applied pressure to the outside, and is connected to, for example, a flexible board or a lead wire for external connection. The upper surface of the terminal portion 41 may be covered with a metal having better solderability than the terminal portion 41. Although the resistor portion 31 and the terminal portion 41 are denoted by different reference numerals for convenience, the two can be integrally formed from the same material in the same process.

[0039] The terminal portions 42 extend from both ends of each of the resistor portions 32 on the lower surface 10b of the substrate 10, and are formed in a generally rectangular shape wider than the resistor portions 32 in a plan view. The terminal portions 42 are a pair of electrodes for outputting to the outside a change in resistance value of the resistor portions 32 caused by an applied pressure, and are connected to, for example, a flexible board or a lead wire for external connection. The upper surface of the terminal portion 42 may be covered with a metal having better solderability than the terminal portion 42. Although the resistor portions 32 and the terminal portions 42 are denoted by different reference numerals for convenience, the two can be integrally formed from the same material in the same process.

[0040] It is also possible to provide a through-hole that penetrates the base material 10, and to concentrate the terminals 41 and 42 on the upper surface 10a side or the lower surface 10b side of the base material 10.

[0041] A cover layer (insulating resin layer) may be provided on the upper surface 10a of the substrate 10 so as to cover the resistor portion 31 and expose the terminal portion 41. Also, a cover layer (insulating resin layer) may be provided on the lower surface 10b of the substrate 10 so as to cover the resistor portion 32 and expose the terminal portion 42. By providing the cover layer, mechanical damage and the like can be prevented from occurring to the resistor portions 31 and 32. Also, by providing the cover layer, the resistor portions 31 and 32 can be protected from moisture and the like. The cover layer may be provided so as to cover the entire portion except for the terminal portions 41 and 42.

[0042] The cover layer can be formed from an insulating resin such as PI resin, epoxy resin, PEEK resin, PEN resin, PET resin, PPS resin, composite resin (e.g., silicone resin, polyolefin resin), etc. The cover layer may contain a filler or a pigment. The thickness of the cover layer is not particularly limited and can be appropriately selected depending on the purpose, but can be, for example, about 2 μm to 30 μm.

[0043] To manufacture the sensor 1, first, the substrate 10 is prepared, and the resistor portion 31 and the terminal portion 41 having a planar shape as shown in Fig. 3 are formed on the upper surface 10a of the substrate 10. The material and thickness of the resistor portion 31 and the terminal portion 41 are as described above. The resistor portion 31 and the terminal portion 41 can be integrally formed from the same material.

[0044] The resistance portion 31 and the terminal portion 41 can be formed, for example, by forming a film by magnetron sputtering using a raw material capable of forming the resistance portion 31 and the terminal portion 41 as a target, and patterning the film by photolithography. Instead of magnetron sputtering, the resistance portion 31 and the terminal portion 41 may be formed by reactive sputtering, vapor deposition, arc ion plating, pulsed laser deposition, or the like.

[0045] From the viewpoint of stabilizing the temperature coefficient of the resistance portion 31 and improving the sensitivity of the resistance portion 31 to applied pressure, it is preferable to vacuum-form a functional layer of a predetermined thickness as a base layer before forming the resistance portion 31 and the terminal portion 41. The functional layer can be formed by, for example, a conventional sputtering method. After the resistance portion 31 and the terminal portion 41 are formed on the entire upper surface of the functional layer, the functional layer is patterned by photolithography together with the resistance portion 31 and the terminal portion 41 into the planar shape shown in FIG. 3.

[0046] In the present application, the functional layer refers to a layer having a function of promoting crystal growth of at least the upper layer, the resistor section. The functional layer preferably further has a function of preventing oxidation of the resistor section due to oxygen or moisture contained in the substrate 10, and a function of improving adhesion between the substrate 10 and the resistor section. The functional layer may further have other functions.

[0047] Since the insulating resin film that constitutes the substrate 10 contains oxygen and moisture, it is effective for the functional layer to have the function of preventing oxidation of the resistor portion, particularly when the resistor portion contains Cr, since Cr forms a self-oxidized film.

[0048] The material of the functional layer is not particularly limited as long as it has the function of promoting the crystal growth of at least the upper layer, the resistor portion, and can be appropriately selected depending on the purpose. For example, Cr (chromium), Ti (titanium), V (vanadium), Nb (niobium), Ta (tantalum), Ni (nickel), Y (yttrium), Zr (zirconium), Hf (hafnium), Si (silicon), C (carbon), Zn (zinc), Cu (copper), Bi (bismuth), F Examples of the metal include one or more metals selected from the group consisting of e (iron), Mo (molybdenum), W (tungsten), Ru (ruthenium), Rh (rhodium), Re (rhenium), Os (osmium), Ir (iridium), Pt (platinum), Pd (palladium), Ag (silver), Au (gold), Co (cobalt), Mn (manganese), and Al (aluminum), an alloy of any of the metals in this group, or a compound of any of the metals in this group.

[0049] Examples of the alloy include FeCr, TiAl, FeNi, NiCr, CrCu, etc. Examples of the compound include TiN, TaN, Si 3 N 4 , TiO 2 , Ta 2 O 5 , SiO 2 etc.

[0050] When the functional layer is made of a conductive material such as a metal or alloy, the thickness of the functional layer is preferably 1 / 20 or less of the thickness of the resistor section. In this range, the crystal growth of α-Cr can be promoted, and a part of the current flowing through the resistor section can be prevented from flowing through the functional layer, which would otherwise reduce the strain detection sensitivity.

[0051] When the functional layer is made of a conductive material such as a metal or alloy, the thickness of the functional layer is preferably 1 / 50 or less of the thickness of the resistor section. In this range, the crystal growth of α-Cr can be promoted, and the strain detection sensitivity can be further prevented from being reduced due to a part of the current flowing through the resistor section flowing through the functional layer.

[0052] When the functional layer is made of a conductive material such as a metal or alloy, the thickness of the functional layer is more preferably 1 / 100 or less of the thickness of the resistor section. In this range, it is possible to further prevent a part of the current flowing through the resistor section from flowing through the functional layer, which would otherwise cause a decrease in strain detection sensitivity.

[0053] When the functional layer is made of an insulating material such as an oxide or a nitride, the thickness of the functional layer is preferably 1 nm to 1 μm, which can promote the crystal growth of α-Cr and can be easily formed without cracking the functional layer.

[0054] When the functional layer is made of an insulating material such as an oxide or nitride, the thickness of the functional layer is preferably 1 nm to 0.8 μm, which can promote the crystal growth of α-Cr and can be easily formed without cracking the functional layer.

[0055] When the functional layer is made of an insulating material such as an oxide or nitride, the thickness of the functional layer is more preferably 1 nm to 0.5 μm, which can promote the crystal growth of α-Cr and can be more easily formed without cracking the functional layer.

[0056] The planar shape of the functional layer is patterned, for example, to be substantially the same as the planar shape of the resistor portion shown in FIG. 3. However, the planar shape of the functional layer is not limited to being substantially the same as the planar shape of the resistor portion. When the functional layer is made of an insulating material, it does not have to be patterned to be the same as the planar shape of the resistor portion. In this case, the functional layer may be formed in a solid shape at least in the region where the resistor portion is formed. Alternatively, the functional layer may be formed in a solid shape over the entire upper surface of the substrate 10.

[0057] Furthermore, when the functional layer is made of an insulating material, the functional layer is formed relatively thick, at a thickness of 50 nm to 1 μm, and formed in a solid form, so that the thickness and surface area of ​​the functional layer are increased, and the heat generated by the resistance portion can be dissipated to the substrate 10. As a result, the deterioration of the measurement accuracy of the sensor 1 due to self-heating of the resistance portion can be suppressed.

[0058] The functional layer can be formed in vacuum by conventional sputtering, for example, using a raw material capable of forming the functional layer as a target and introducing Ar (argon) gas into a chamber. By using conventional sputtering, the functional layer is formed while etching the upper surface 10a of the substrate 10 with Ar, so that the amount of the functional layer formed can be minimized and the effect of improving adhesion can be obtained.

[0059] However, this is just one example of a method for forming the functional layer, and the functional layer may be formed by other methods. For example, a method may be used in which the upper surface 10a of the substrate 10 is activated by a plasma treatment using Ar or the like before forming the functional layer, thereby improving adhesion, and then the functional layer is vacuum-formed by magnetron sputtering.

[0060] There is no particular limitation on the combination of the material of the functional layer and the materials of the resistor portion 31 and the terminal portion 41, and the combination can be appropriately selected according to the purpose. For example, it is possible to use Ti for the functional layer, and form a Cr mixed phase film containing α-Cr (alpha chromium) as the main component for the resistor portion 31 and the terminal portion 41.

[0061] In this case, for example, the resistor portion 31 and the terminal portion 41 can be formed by magnetron sputtering in which a raw material capable of forming a Cr mixed phase film is used as a target and Ar gas is introduced into the chamber. Alternatively, the resistor portion 31 and the terminal portion 41 may be formed by reactive sputtering in which a proper amount of nitrogen gas is introduced into the chamber together with Ar gas using pure Cr as a target. In this case, the amount and pressure of the nitrogen gas introduced (nitrogen partial pressure) can be changed, or a heating process can be performed to adjust the heating temperature, thereby allowing the CrN and CrN contained in the Cr mixed phase film to be uniformly distributed. 2 The proportion of N, CrN and Cr 2 Cr in N 2 The ratio of N can be adjusted.

[0062] In these methods, the growth surface of the Cr mixed-phase film is determined by the functional layer made of Ti, and a Cr mixed-phase film containing α-Cr, which has a stable crystal structure, as the main component, can be formed. Furthermore, the Ti constituting the functional layer is diffused into the Cr mixed-phase film, which can stabilize the temperature coefficient of the resistor 31 and improve the sensitivity of the resistor 31 to applied pressure. When the functional layer is made of Ti, the Cr mixed-phase film may contain Ti or TiN (titanium nitride).

[0063] When the resistor portion 31 is a Cr mixed phase film, the functional layer made of Ti has all of the following functions: promoting crystal growth of the resistor portion 31, preventing oxidation of the resistor portion 31 due to oxygen and moisture contained in the substrate 10, and improving adhesion between the substrate 10 and the resistor portion 31. The same applies when Ta, Si, Al, or Fe is used as the functional layer instead of Ti.

[0064] In this way, by providing a functional layer below the resistance portion 31, it is possible to promote crystal growth of the resistance portion 31, and to fabricate the resistance portion 31 made of a stable crystal phase. As a result, it is possible to stabilize the temperature coefficient of the resistance portion 31 and improve the sensitivity of the resistance portion 31 to applied pressure in the sensor 1. In addition, by diffusing the material constituting the functional layer into the resistance portion 31, it is possible to stabilize the temperature coefficient of the resistance portion 31 and improve the sensitivity of the resistance portion 31 to applied pressure in the sensor 1.

[0065] Next, the resistor portion 32 and the terminal portion 42 having the planar shape shown in Fig. 3 are formed on the lower surface 10b of the substrate 10. The resistor portion 32 and the terminal portion 42 can be formed in the same manner as the resistor portion 31 and the terminal portion 41. It is also preferable to form a functional layer as a base layer on the lower surface 10b of the substrate 10 before forming the resistor portion 32 and the terminal portion 42.

[0066] After forming the resistance portion 31 and the terminal portion 41, and the resistance portion 32 and the terminal portion 42, if necessary, a cover layer that covers the resistance portion 31 and exposes the terminal portion 41 may be provided on the upper surface 10a of the substrate 10, and a cover layer that covers the resistance portion 32 and exposes the terminal portion 42 may be provided on the lower surface 10b of the substrate 10. In this manner, the sensor 1 is completed.

[0067] The cover layer can be produced, for example, by laminating a semi-cured thermosetting insulating resin film on the upper surface 10a of the base material 10 so as to cover the resistor portion 31 and expose the terminal portion 41, and then heating and curing the film. The cover layer can also be produced, for example, by laminating a semi-cured thermosetting insulating resin film on the lower surface 10b of the base material 10 so as to cover the resistor portion 32 and expose the terminal portion 42, and then heating and curing the film. Instead of laminating an insulating resin film, the cover layer may also be produced by applying a liquid or paste-like thermosetting insulating resin, and then heating and curing the resin.

[0068] When a functional layer is provided on the upper surface 10a of the substrate 10 as an underlayer for the resistor portion 31 and the terminal portion 41, and when a functional layer is provided on the lower surface 10b of the substrate 10 as an underlayer for the resistor portion 32 and the terminal portion 42, the sensor 1 has a cross-sectional shape as shown in Fig. 5. The layers indicated by the reference characters 20a and 20b are functional layers. The planar shape of the sensor 1 when the functional layers 20a and 20b are provided is the same as that shown in Fig. 3.

[0069] 6, a pressure distribution detection device 3 can be realized by a sensor 1 and a control device 2. The pressure distribution detection device 3 is a device that detects the pressure distribution applied to a tire 100 from a road surface. In the pressure distribution detection device 3, each of terminal portions 41 and 42 of the sensor 1 is connected to the control device 2 using, for example, a flexible substrate, a lead wire, or the like.

[0070] The control device 2 can detect the pressure distribution applied to the tire 100 from the road surface based on the information obtained via the terminal units 41 and 42 of the sensor 1. That is, the resistor unit 31 of the sensor 1 can be used to detect the X coordinate, and the resistor unit 32 can be used to detect the Y coordinate, so that it is possible to detect the XY coordinates of the position where the pressure is applied and the magnitude of the applied pressure.

[0071] As shown in FIG. 7, the control device 2 can include, for example, an analog front-end unit 21 and a signal processing unit 22.

[0072] The analog front-end unit 21 includes, for example, an input signal selection switch, a bridge circuit, an amplifier, an analog / digital conversion circuit (A / D conversion circuit), etc. The analog front-end unit 21 may include a temperature compensation circuit.

[0073] In the analog front-end unit 21, for example, all the terminals 41 and 42 of the sensor 1 are connected to an input signal selection switch, and a pair of electrodes is selected by the input signal selection switch. The pair of electrodes selected by the input signal selection switch is connected to a bridge circuit.

[0074] That is, one side of the bridge circuit is composed of a resistor section between a pair of electrodes selected by the input signal selection switch, and the other three sides are composed of fixed resistors. This makes it possible to obtain, as the output of the bridge circuit, a voltage (analog signal) corresponding to the resistance value of the resistor section between a pair of electrodes selected by the input signal selection switch. The input signal selection switch is configured to be controllable by the signal processing unit 22.

[0075] The voltage output from the bridge circuit is amplified by the amplifier, converted into a digital signal by the A / D conversion circuit, and sent to the signal processing unit 22. If the analog front-end unit 21 is equipped with a temperature compensation circuit, a temperature-compensated digital signal is sent to the signal processing unit 22. By switching the input signal selection switch at high speed, digital signals corresponding to the resistance values ​​of all of the terminal units 41 and 42 of the sensor 1 can be sent to the signal processing unit 22 in an extremely short time.

[0076] The signal processing unit 22 can detect the pressure distribution acting on the tire 100 from the road surface based on the information sent from the analog front end unit 21 .

[0077] Depending on the magnitude of the applied pressure, pressure may be applied to only one of the resistors 31 and 32. In this case, only the resistance value between a pair of electrodes of one of the resistors changes continuously according to the magnitude of the applied pressure, but even in this case, the signal processor 22 can detect the magnitude of the applied pressure based on the magnitude of the change in the resistance value of the resistors.

[0078] In other words, when pressure is applied to the resistance portion 31 and / or the resistance portion 32, the resistance value between the pair of electrodes of the pressurized resistance portion (resistance portion 31 and / or the resistance portion 32) changes continuously according to the magnitude of the applied pressure. Then, the signal processing portion 22 can detect the magnitude of the applied pressure based on the magnitude of the change in the resistance value of the pressurized resistance portion, regardless of whether pressure is applied to one or both of the resistance portions 31 and 32.

[0079] The signal processing unit 22 may include, for example, a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), a main memory, and the like.

[0080] In this case, the various functions of the signal processing unit 22 can be realized by reading a program recorded in a ROM or the like into a main memory and executing the program by a CPU. However, a part or the whole of the signal processing unit 22 may be realized only by hardware. Furthermore, the signal processing unit 22 may be physically configured by a plurality of devices or the like.

[0081] In this way, when pressure is applied to the resistance parts 31 and 32 of the sensor 1, the pressured resistance parts 31 and 32 bend according to the magnitude of the applied pressure, and the resistance value between a pair of electrodes of the pressured resistance parts 31 and 32 changes continuously according to the magnitude of the applied pressure. That is, the sensor 1 can obtain three-dimensional information (the coordinates of the position where pressure is applied and the magnitude of the applied pressure).

[0082] In the pressure distribution detection device 3 , the three-dimensional information obtained by the sensor 1 is sent to the control device 2 , and the control device 2 can detect the pressure distribution acting on the tire 100 based on the three-dimensional information obtained by the sensor 1 .

[0083] For example, by storing the pressure distribution in an initial state (e.g., a state in which the tire 100 is not unevenly worn and the air pressure is normal) and monitoring the output of the sensor 1 while the moving object is traveling and comparing it with the initial state, it is possible to monitor the wear state of the contact surface of the tire 100 and changes in the air pressure in real time. As a result, it is possible to detect uneven wear of the tire 100. It is also possible to detect whether the air pressure of the tire 100 is appropriate. It is also possible to grasp the adjustment angle of the tire 100 and the time to replace the tire 100.

[0084] Furthermore, abnormal pressure distribution on the tire 100 can be detected in real time and reported to the driver by radio or the like, allowing for more accurate management of the tire 100 condition.

[0085] In addition, since the wear state of the contact surface of the tire 100 can be constantly monitored, the risk of accidents caused by bursts or steering errors can be avoided.

[0086] In particular, when the resistors 31 and 32 are made of a Cr mixed-phase film, the sensitivity of the resistance value to the applied pressure (the amount of change in the resistance value of the resistors 31 and 32 when the same pressure is applied) is significantly improved compared to when the resistors 31 and 32 are made of Cu-Ni or Ni-Cr. When the resistors 31 and 32 are made of a Cr mixed-phase film, the sensitivity of the resistance value to the applied pressure is approximately 5 to 10 times higher compared to when the resistors 31 and 32 are made of Cu-Ni or Ni-Cr. Therefore, by forming the resistors 31 and 32 from a Cr mixed-phase film, the detection accuracy of the coordinates of the position where pressure is applied can be improved, and the applied pressure can be detected with high sensitivity.

[0087] In addition, the high sensitivity of the resistance value to the applied pressure makes it possible to realize control such that a predetermined operation is performed when the applied pressure is detected to be small, another operation is performed when the applied pressure is detected to be medium, and yet another operation is performed when the applied pressure is detected to be large, or such that no operation is performed when the applied pressure is detected to be small or medium, and a predetermined operation is performed only when the applied pressure is detected to be large.

[0088] Furthermore, if the resistance value is highly sensitive to the applied pressure, a signal with a high S / N ratio can be obtained. Therefore, even if the number of averaging operations is reduced in the A / D conversion circuit of the analog front-end unit 21, accurate signal detection is possible. By reducing the number of averaging operations in the A / D conversion circuit, the time required for one A / D conversion can be shortened, making it possible to switch the input signal selection switch at even higher speeds. As a result, the sensor 1 can detect pressure distributions that are relatively fast.

[0089] First Modification of the First Embodiment In the first modification of the first embodiment, an example of a sensor having electronic components mounted on one surface side or the other surface side of a substrate is shown. Note that in the first modification of the first embodiment, the description of the same components as those in the already described embodiments may be omitted.

[0090] Fig. 8 is a cross-sectional view illustrating a sensor according to Modification 1 of the first embodiment, and shows a cross section corresponding to Fig. 4. Referring to Fig. 8, sensor 1A differs from sensor 1 (see Figs. 3 and 4) in that an electronic component 200 is mounted on the lower surface 10b of the substrate 10.

[0091] The electronic component 200 is, for example, an IC that is implemented as an analog front-end unit 21 shown in FIG. 2The electronic component 200 is provided with a serial communication function such as serial communication with a serial communication device (eg, serial communication with a serial communication interface (serial communication function) such as serial communication with a serial communication device (serial communication function such as ... function

[0092] The electronic component 200 can be flip-chip mounted, for example, to a pad formed on the lower surface 10b of the substrate 10. Alternatively, the electronic component 200 may be mounted on the lower surface 10b of the substrate 10 via an adhesive layer such as a die attach film, and wire-bonded to the pad formed on the lower surface 10b of the substrate 10. Furthermore, a passive component such as a capacitor may be mounted together with the electronic component 200.

[0093] The electronic component 200 is connected to all of the terminals 41 and 42 via a wiring pattern or through-holes (not shown). The electronic component 200 is configured so that power can be supplied from outside the sensor 1A.

[0094] A cover layer (insulating resin layer) may be provided on the upper surface 10a of the substrate 10 so as to cover the resistor portion 31 and the terminal portion 41. Also, a cover layer (insulating resin layer) may be provided on the lower surface 10b of the substrate 10 so as to cover the resistor portion 32, the terminal portion 42, and the electronic component 200. By providing the cover layer, it is possible to prevent mechanical damage, etc. from occurring to the resistor portions 31 and 32, the terminal portions 41 and 42, and the electronic component 200. Also, by providing the cover layer, it is possible to protect the resistor portions 31 and 32, the terminal portions 41 and 42, and the electronic component 200 from moisture, etc.

[0095] In this way, in the sensor 1A, since the electronic component 200 is mounted on the substrate 10, the terminals 41 and 42 can be connected to the electronic component 200 over a short distance via a wiring pattern or a through-hole. This allows a small sensor 1A to be realized. This structure is particularly effective for small sensors in which it is difficult to connect the resistor and the electronic component by soldering or the like using lead wires.

[0096] Moreover, by shortening the distance from the terminals 41 and 42 to the electronic component 200, the noise resistance can be improved.

[0097] The electronic component 200 is not limited to an IC having the functions of the analog front-end unit 21, and may be, for example, an IC having the functions of the analog front-end unit 21 and the signal processing unit 22.

[0098] That is, a part or all of the control device 2 may be integrated with the sensor 1A. Here, integration with the sensor 1A includes sharing a part or all of the substrates and electronic components used in the control device 2 with a part or all of the substrates and electronic components used in the sensor 1A.

[0099] Furthermore, the control device 2 may be provided with an integrated circuit or the like that wirelessly transmits the detection results by the signal processing unit 22. The detection results by the signal processing unit 22 may be wirelessly transmitted to, for example, an ECU (Electronic Control Unit) mounted on the vehicle. If the ECU obtains information on the pressure distribution of the tire 100 wirelessly from the control device 2, for example, when the pressure distribution is abnormal, it can notify the driver of the abnormality by displaying a warning or sounding a buzzer. This allows the vehicle to be driven safely and prevents accidents from occurring.

[0100] Second Modification of the First Embodiment In the second modification of the first embodiment, an example of a sensor having a power source mounted on one surface side or the other surface side of a substrate is shown. Note that in the second modification of the first embodiment, the description of the same components as those in the already described embodiments may be omitted.

[0101] Fig. 9 is a cross-sectional view illustrating a sensor according to Modification 2 of the first embodiment, and shows a cross section corresponding to Fig. 4. Referring to Fig. 9, sensor 1B differs from sensor 1A (see Fig. 8) in that a power source 300 is mounted thereon.

[0102] The power source 300 is, for example, a small battery such as a lithium ion battery. The power source 300 is mounted, for example, on the lower surface 10b side of the substrate 10 and is electrically connected to the electronic component 200. The power source 300 may also be mounted on the upper surface 10a side of the substrate 10.

[0103] In this manner, the sensor 1B is equipped with the power supply 300 that supplies power to the electronic component 200. This makes it possible to realize a compact sensor 1B that does not require power supply from an external source.

[0104] In the sensor 1B, by making the resistor 30 thin, it is possible to reduce the power consumption and size of the sensor 1B in particular.

[0105] That is, when a Cu-Ni or Ni-Cr foil is used as the material of the resistor 30, the resistance value of the resistor 30 is about 1 kΩ, but when a thin Cr mixed-phase film is used as the material of the resistor 30, the resistance value of the resistor 30 can be made 5 kΩ or more. Therefore, when a Cr mixed-phase film is used as the material of the resistor 30, the current flowing through the resistor 30 is reduced, making it possible to reduce power consumption. Furthermore, since the current supplied from the power source 300 is reduced due to the reduced power consumption, a small power source 300 can be used, and the entire sensor 1B can be made smaller.

[0106] <Modification 3 of the First Embodiment> In the third modification of the first embodiment, an example in which the resistor portion of the sensor is formed in a zigzag pattern will be described. Note that in the third modification of the first embodiment, the description of the same components as those in the embodiments already described may be omitted.

[0107] Fig. 10 is a plan view illustrating a sensor according to Modification 3 of the first embodiment, showing a plane corresponding to Fig. 3. Referring to Fig. 10, sensor 1C differs from sensor 1 (see Figs. 3 and 4) in that resistor 30 is replaced with resistor 30C.

[0108] The resistor 30C includes resistive portions 31C and 32C. The resistive portion 31C has a zigzag pattern formed between a pair of terminal portions 41. The resistive portion 32C has a zigzag pattern formed between a pair of terminal portions 42. The material and thickness of the resistive portions 31C and 32C can be the same as the material and thickness of the resistive portions 31 and 32, for example.

[0109] In this way, by forming the resistance portions 31C and 32C in a zigzag pattern, it is possible to increase the resistance value between the pair of terminal portions 41 and the resistance value between the pair of terminal portions 42, compared to when they are formed in a linear pattern. As a result, the amount of change in the resistance value between the pair of terminal portions 41 and the amount of change in the resistance value between the pair of terminal portions 42 when pressure is applied increases, so that the detection accuracy of the pressure distribution applied to the tire 100 can be further improved.

[0110] Furthermore, since the resistance value between the pair of terminal portions 41 and the resistance value between the pair of terminal portions 42 can be increased, the power consumption of the sensor 1C can be reduced.

[0111] Although preferred embodiments have been described above in detail, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0112] For example, in the sensor 1, an example is shown in which the resistance portion 31 is provided on the upper surface 10a of the substrate 10, which is an insulating layer, and the resistance portion 32 is provided on the lower surface 10b. However, as long as the resistance portion 32 is provided on one side of the insulating layer and the resistance portion 32 is provided on the other side, the present invention is not limited to this. For example, the resistance portion 31 may be provided on the upper surface 10a of the substrate 10, an insulating layer that covers the resistance portion 31 may be provided on the upper surface 10a of the substrate 10, and the resistance portion 32 may be provided on the insulating layer. Alternatively, a first substrate provided with the resistance portion 31 and a second substrate provided with the resistance portion 32 may be fabricated, and the first substrate provided with the resistance portion 31 and the second substrate provided with the resistance portion 32 may be bonded together with the insulating layer sandwiched between them, with the resistance portion 31 and the resistance portion 32 facing inward. Alternatively, a first substrate provided with the resistance portion 31 and a second substrate provided with the resistance portion 32 may be fabricated, and the first substrate provided with the resistance portion 31 and the second substrate provided with the resistance portion 32 may be laminated in the same direction. The same is true for sensors 1A, 1B, and 1C. [Explanation of symbols]

[0113] 1, 1A, 1B, 1C sensor, 2 control device, 3 pressure distribution detection device, 10 substrate, 10a upper surface of substrate, 10b lower surface of substrate, 20a, 20b functional layer, 21 analog front end section, 22 signal processing section, 30, 30C resistor, 31, 31C, 32, 32C resistor section, 41, 42 terminal section, 100 tire, 110 tread section, 120 sidewall section, 130 bead section, 140 inner liner, 150 carcass, 160 bead core, 170 bead filler, 180 belt, 200 electronic component, 300 power supply

Claims

[Claim 1] A tire for a moving object, A sensor is provided on the inside of the tire, The sensor includes: An insulating layer; a plurality of first resistor portions arranged side by side on one side of the insulating layer with their longitudinal directions aligned in a first direction; a plurality of second resistors arranged side by side on the other side of the insulating layer with their longitudinal directions directed in a second direction intersecting the first direction; a pair of electrodes provided at both ends of each of the first resistor portions and each of the second resistor portions; the first resistor portion and the second resistor portion are formed from a film containing Cr, CrN, and Cr 2 N, the film being mainly composed of α-Cr; The ratio of CrN and Cr 2 N contained in the first resistor portion and the second resistor portion is 20% by weight or less, The ratio of the CrN and the Cr 2 N in the Cr 2 N is 80% by weight or more and less than 90% by weight, A tire in which, when the first resistance portion and / or the second resistance portion is pressed, the resistance value between the pair of electrodes of the pressed first resistance portion and / or the pressed second resistance portion changes continuously depending on the magnitude of the applied pressure.

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