JP2015077958A - Power generation device, tire assembling body and autonomous power generating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power generation device which is of a cheap and simple structure and is excellent in endurance.SOLUTION: The power generation device is a device which is fitted to the inside of a tire and generates power from mechanical energy of the tire, and comprises a first electrode structure body including a first electrode, a second electrode structure body including a second electrode and a fixing part which fixes the first electrode structure and the second electrode structure so that the mutual facing distance becomes variable. At least one side of each electrode structure includes a charged body for generating static electricity at the facing surface side, the first electrode structure is fixed to the tire and the second electrode structure is made as movable against the first electrode structure. And, static electricity is generated by contacting of the charged body to the facing electrode structure, corresponding to the deformation of the tire, and voltage is generated between the first electrode and the second electrode by widening of the facing distance between the electrode structures, corresponding to the deformation of the tire.

Description

  The present invention relates to a power generation device that generates power from the energy of a rotating tire, a tire assembly including the power generation device, and an autonomous power generation system.

  As disclosed in Patent Document 1, a tire assembly that generates electric power from mechanical energy of a rotating tire is known. The tire assembly includes a piezoelectric device that contributes to generation of electric charges, and the piezoelectric device supplies electric power to electronic components in the tire assembly.

JP 2006-151372 A

  Piezoelectric devices generally use a piezoelectric body using PZT (lead zirconate titanate), but there is a problem that PZT contains lead which is harmful to the environment. This problem can be dealt with by using an alternative substance such as lead-free sodium potassium niobate as the piezoelectric body, but the electric power obtained is smaller than that of a generally used piezoelectric body such as PZT. If the piezoelectric device is enlarged in order to increase the electric power, there is a problem that the cost increases. That is, there is a problem that it is difficult to expand the area for increasing power.

  In the piezoelectric device, electric power is generated by expansion and contraction of a piezoelectric body that is a solid. In an environment that undergoes a large change in acceleration, such as a rotating tire, there is a possibility that the piezoelectric body may be damaged and power supply cannot be performed.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a power generator that is inexpensive and excellent in durability. It is another object of the present invention to provide a tire assembly and an autonomous power generation system provided with such a power generation device.

  The invention disclosed herein employs the following technical means to achieve the above object. Note that the reference numerals in parentheses described in the claims and in this section indicate a corresponding relationship with specific means described in the embodiments described later as one aspect, and limit the technical scope of the invention. Not what you want.

  In order to achieve the above object, the present invention is an electric power generation apparatus that is assembled inside a tire (100) and generates electric power from the mechanical energy of the tire, and is a pair of opposed electrode structures (15, 16). As the first electrode structure (15) having the first electrode (11) and the second electrode structure (16) having the second electrode (12), the first electrode structure and the second electrode structure, And a fixing portion (17) for fixing the first electrode structure and the second electrode structure to generate static electricity on the opposite surface side. The first electrode structure is fixed to the tire, and the second electrode structure is movable with respect to the first electrode structure, so that the tire is deformed. Accordingly, the charged body comes into contact with the opposing electrode structure. As a result, static electricity is generated, and the opposing distance between the first electrode structure and the second electrode structure is increased according to the deformation of the tire, thereby generating a voltage between the first electrode and the second electrode. It is characterized by.

  According to this, static electricity can be generated between the first electrode structure and the second electrode structure, and a potential difference can be generated between them. That is, electrostatic energy can be accumulated between the first electrode structure and the second electrode structure. The electrostatic energy generated by this charging can be stored in the battery or used for driving the electronic device. That is, it is possible to generate electric power without using a piezoelectric body that causes high costs. Moreover, durability can be improved compared with the conventional structure using a highly rigid piezoelectric material.

It is sectional drawing which shows schematic structure of the tire assembly which concerns on 1st Embodiment. It is sectional drawing which shows the detail which expanded the II area | region in FIG. It is a figure which shows the state which produced the space | gap in sectional drawing to which the III area | region in FIG. 2 was expanded. It is a figure which shows the state which the space | gap disappeared in sectional drawing to which the III area | region in FIG. 2 was expanded. It is a figure which shows schematic structure of an electric power generator and an autonomous electric power generation system. It is sectional drawing which shows schematic structure of the electric power generator which concerns on 2nd Embodiment. FIG. 6 is a cross-sectional view illustrating a schematic configuration of a power generation device according to a first modification. FIG. 6 is a cross-sectional view illustrating a schematic configuration of a power generation device according to a first modification. FIG. 10 is a cross-sectional view illustrating a schematic configuration of a power generation device according to Modification 2. It is sectional drawing which shows schematic structure of the electric power generator which concerns on 3rd Embodiment. It is sectional drawing which shows schematic structure of the electric power generator which concerns on 3rd Embodiment. It is sectional drawing which shows schematic structure of the tire assembly which concerns on 4th Embodiment. It is sectional drawing which shows schematic structure of the electric power generator which concerns on other embodiment. It is a figure which shows schematic structure of the electric power generator and autonomous power generation system which concern on 5th Embodiment. It is the schematic which shows the calculation method of tire rotation speed. It is sectional drawing which shows schematic structure of the autonomous electric power generation system which concerns on 6th Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same reference numerals are given to the same or equivalent parts. 3, 4, and 5 to 11 are all enlarged cross-sectional views corresponding to the region III in FIG. 2.

(First embodiment)
Initially, with reference to FIGS. 1-5, the schematic structure of the electric power generator which concerns on this embodiment is demonstrated.

  The power generation device according to the present embodiment is mounted on, for example, a vehicle and charges a battery in the vehicle or supplies power to an electronic device. As shown in FIGS. 1 and 2, for example, the power generation device 10 is assembled inside a tire 100. When the vehicle travels, the tire 100 performs a rotational movement, and is deformed by receiving an external force from the road surface. The power generation device 10 converts mechanical energy generated by deformation of the tire 100 into electric power.

  FIG. 1 illustrates a cross section along the rotation axis of the tire 100. FIG. 2 is an enlarged view of a region II in FIG. 1, and shows only the front left portion of the tire 100 when the vehicle upper direction is the traveling direction of the vehicle. The above-described electronic device is, for example, a pressure sensor that detects tire air pressure and a control unit for the pressure sensor, and is disposed inside the tire 100. However, in FIG. 2, illustration of the electronic device and the battery is omitted. .

  First, with reference to FIG. 1 and FIG. 2, the tire 100 to which the power generation device 10 is assembled will be briefly described. The tire 100 in the present embodiment is generally used well, and detailed description thereof is omitted.

  As shown in FIG. 1, the tire 100 is fixed to the wheel rim 200 so as to surround the wheel rim 200 of the wheel. As shown in FIG. 2, the tire 100 can be classified into a tread portion 100A, a shoulder portion 100B, a sidewall portion 100C, and a bead portion 100D. The tread portion 100A is a portion in contact with the road surface, and the tire resin body 110 described later has the largest thickness. The shoulder portion 100B is a portion adjacent to the tread portion 100A, and contacts the road surface when the vehicle performs a turning motion. The sidewall portion 100C is a portion adjacent to the shoulder portion 100B, and does not contact the road surface, but is a portion that bends for the purpose of alleviating the impact received from the road surface. The bead portion 100 </ b> D is a portion that fixes the tire 100 to the wheel rim 200.

  The tire 100 retains the tire resin body 110 that can be elastically deformed, the belt 120 that reinforces the tire resin body 110 to improve rigidity, the tire resin body 110, and durability against the load and impact received by the tire 100. A carcass 130 to be improved.

  The tire resin body 110 is made of a mixture containing synthetic rubber or natural rubber as a main component and a compounding agent such as carbon or sulfur, and is elastically deformable. The tire resin body 110 is fixed to the wheel rim 200 at the bead portion 100 </ b> D so that a hollow portion 300 for filling air is formed between the tire resin body 110 and the wheel rim 200.

  The belt 120 is formed in a belt shape by knitting a metal wire, for example, a steel wire, and is embedded in the tire resin body 110. The belt 120 is stretched in the circumferential direction (rotating direction) of the tire 100 on a portion from the tread portion 100A through the shoulder portion 100B to a part of the sidewall portion 100C.

  The carcass 130 is made of, for example, a polyamide-based or polyester-based fiber, and is embedded between the belt 120 and the hollow portion 300 in the tire resin body 110. The carcass 130 is formed to extend from the left bead portion 100 </ b> D to the right bead portion (not shown) in the traveling direction, and functions as a skeleton of the tire 100.

  Further, the tire 100 has a bead 140 in the bead portion 100D. The bead 140 has a structure in which high carbon steel is bundled. The bead 140 fixes the tire resin body 110 to the wheel rim 200 and also fixes both ends of the carcass 130.

  Next, a schematic configuration of the power generation device 10 will be described with reference to FIGS. 2 and 3.

  As shown in FIG. 2, the power generation device 10 is disposed inside the tire 100, that is, in a hollow portion 300 formed by being surrounded by the tire 100 and the wheel rim 200. The power generation device 10 is fixed to the sidewall portion 100 </ b> C of the tire 100. As described above, the power generation device 10 and the tire 100 constitute a tire assembly.

  As illustrated in FIG. 3, the power generation device 10 includes a flat plate-like first electrode 11 and a second electrode 12 that faces the first electrode 11. A first charged body 13 is formed on the surface of the first electrode 11 facing the second electrode 12. A second charged body 14 is formed on the surface of the second electrode 12 facing the first electrode 11. In other words, the first charged body 13 and the second charged body 14 are arranged to face each other.

  The first electrode 11 and the first charged body 13 are joined to form an integrated first electrode structure 15. Similarly, the second electrode 12 and the second charged body 14 are joined to form an integrated second electrode structure 16. The first electrode structure 15 and the second electrode structure 16 are fixed to each other by a fixing portion 17 at their ends. The first electrode structure 15 is fixed to the tire 100 together with the fixing portion 17. More specifically, the first electrode 11 constituting the first electrode structure 15 is fixed to the tire resin body 110 via an adhesive (not shown). The second electrode structure 16 has a film shape that can be freely deformed with a portion fixed by the fixing portion 17 as a fixed end. The shape of the second electrode structure 16 can be changed according to the deformation of the tire 100. For this reason, the opposing distance with respect to the 1st electrode structure 15 is variable according to the deformation | transformation of the tire 100 except the part fixed to the 2nd electrode structure 16 by the fixing | fixed part 17. FIG.

  The first electrode structure 15 is formed, for example, by depositing gold (Au) or aluminum (Al) as the first electrode 11 on a polyethylene film as the first charged body 13. On the other hand, the second electrode structure 16 is formed by depositing gold (Au) or aluminum (Al) as the second electrode 12 on the nylon film as the second charged body 14. In the present embodiment, the first electrode structure 15 and the second electrode structure 16 are congruent flat plate-like films.

  The fixing part 17 is, for example, a silicone-based adhesive. The fixing portion 17 fixes the power generation device 10 to the tire 100 while bonding the edges of the first electrode structure 15 and the second electrode structure 16 to each other. In addition, the power generation device 10 in the present embodiment is fixed so that the facing direction of the first electrode structure 15 and the second electrode structure 16 faces the normal direction of the installation surface of the power generation device 10.

  Next, the operation of the power generation device 10 will be described with reference to FIGS. 3 and 4.

  FIG. 3 illustrates a case where the tire 100 is deformed so as to collapse due to stress in the traveling direction. In such a state, the sidewall portion 100C is deformed so as to protrude leftward with respect to the traveling direction. In other words, the sidewall portion 100C is deformed so as to protrude outward from the hollow portion 300. Thereby, the second electrode structure 16 is deformed so as to be bent, and a gap AG is formed between the first electrode structure 15 and the first electrode structure 15.

  On the other hand, when the stress received by the tire 100 is reduced, the sidewall portion 100C is deformed so as to extend. For this reason, as shown in FIG. 4, it deform | transforms so that the bent 2nd electrode structure 16 may be stretched. Thereby, the gap AG disappears. In other words, the first electrode structure 15 and the second electrode structure 16 are in contact with each other. In more detail, the 1st charged body 13 and the 2nd charged body 14 contact.

  The stress received by the tread portion 100A due to contact with the road surface is transmitted to the sidewall portion 100C and contributes to the deformation of the sidewall portion 100C. Since the tire 100 in the traveling vehicle is always in a rotational motion, a certain point in the tread portion 100A repeats contact and separation with the road surface. That is, the sidewall portion 100 </ b> C repeats expansion and contraction periodically as the tire 100 rotates. In other words, the first charged body 13 and the second charged body 14 repeat contact and separation periodically.

  Next, with reference to FIG. 5, the principle of power generation and the effects of the power generation device 10 will be described. In the following description, it is assumed that the first electrode 11 and the second electrode 12 are parallel flat plates that maintain parallel to each other in consideration of the simplicity of the description.

  As described above, the first charged body 13 and the second charged body 14 repeat contact and separation. When the first charged body 13 and the second charged body 14 come into contact with each other, static electricity is generated. When the surface density (hereinafter, referred to as charge density) of the generated charge is σ, the electric field E generated between the first electrode 11 and the second electrode 12 is E = σ / ε. Here, ε is a dielectric constant as a whole in consideration of the dielectric constants of the first charged body 13, the second charged body 14, and the air gap AG.

On the other hand, the potential difference V between the first electrode 11 and the second electrode 12 is V = Ed because the electric field E is constant. Here, as shown in FIG. 5, d is a facing distance when the first charged body 13 and the second charged body 14 are separated from each other. Therefore, when the first charging body 13 and the second charging body 14 are in contact with each other and charged with the charge density σ, and are separated until the mutual facing distance becomes d, they are accumulated in the respective charging bodies 13 and 14. The energy U is expressed by Equation 1.

C is the capacitance of the capacitor when the first electrode 11 and the second electrode 12 are regarded as electrodes, and S is the area of the first electrode 11 and the second electrode 12.

  Although the illustration of the electronic device and the battery is omitted in FIGS. 2 to 4, an electronic circuit 400 is originally connected to the power generation device 10 as shown in FIG. 5. The electronic circuit 400 includes a pressure sensor 410 as an electronic device, a radio 420 that transmits an output signal output from the pressure sensor 410, a battery 430, and a full-wave rectifier diode 440. The energy U stored in each of the charging bodies 13 and 14 becomes electric power stored in the battery 430 or supplied to the pressure sensor 410. Thus, in this embodiment, the autonomous power generation system is constructed by the power generation device 10 and the electronic circuit 400.

  According to Formula 1, the energy U is proportional to the facing distance d between the first charged body 13 and the second charged body 14. Therefore, the power generation device 10 can generate power by repeatedly contacting and separating the first charged body 13 and the second charged body 14 due to deformation of the tire 100. This power generation device 10 has a simple configuration in which a pair of electrode structures 15 and 16 are simply overlapped, and it is not necessary to use a piezoelectric body that is a main cause of high cost, so that the manufacturing cost is suppressed. be able to. Further, when a piezoelectric body is used as in the prior art, since the expansion and contraction of a highly rigid piezoelectric body is used for power generation, the piezoelectric body may cause stress cracking due to aged deterioration or the like. On the other hand, the power generation device 10 has a configuration in which the second electrode structure 16 that is relatively variable with respect to the first electrode structure 15 is provided, so that stress cracking or the like does not occur. For this reason, durability of the electric power generation apparatus 10 can be improved.

  In general, the tire 100 during travel has the largest deformation amount of the sidewall portion 100C. By disposing the power generation device 10 on the sidewall portion 100C as in the present embodiment, the facing distance d between the first charged body 13 and the second charged body 14 can be increased. In particular, the facing distance d can be substantially maximized by making the facing direction of the first electrode structure 15 and the second electrode structure 16 face the normal direction of the installation surface of the power generation device 10. .

  Further, according to Equation 1, the energy U is proportional to the area S of the first electrode 11 and the second electrode 12. Conventionally, it was possible to increase the amount of power generation by increasing the size of the piezoelectric body, but there was a problem that the cost was significantly increased. On the other hand, since the power generation device 10 according to the present embodiment does not use a piezoelectric body that is a main cause of high cost, each electrode 11, 12 and thus each electrode structure 15, while suppressing cost. The area of 16 can be easily increased.

  Further, according to Equation 1, the energy U is proportional to the square of the charge density σ. That is, the amount of charge increases as the amount of charge increases. Therefore, the amount of power generation can be adjusted by selecting the first charged body 13 and the second charged body 14. For example, the power generation amount can be increased by selecting a material at a distant position in the charging train as a combination of the first charging body 13 and the second charging body 14.

(Second Embodiment)
In the present embodiment, an example in which a part of the power generation device 10 also serves as a component of the tire 100 is shown. For example, as shown in FIG. 6, the belt 120 in the tire 100 can also serve as the first electrode 11 in the power generation device 10.

  In the tire assembly including the power generation device 10 and the tire 100, the second electrode structure 16 is fixed to a portion of the belt 120 exposed from the tire resin body 110 to the hollow portion 300. Similar to the first embodiment, the second electrode structure 16 is fixed to the tire 100 by the fixing portion 17, and the central portion can be freely deformed with the fixing portion 17 as a fixed end. The second electrode structure 16 is formed by bonding the second electrode 12 and the second charged body 14 together. For this reason, as the tire 100 is deformed, the belt 120 as the first electrode 11 and the second charged body 14 repeat contact and separation. Thereby, electric power generation can be performed similarly to 1st Embodiment. In such a configuration, since a part of the power generation device 10 can also be used as a component of the tire 100, material saving can be realized in the manufacture of the power generation device 10 and eventually the tire assembly. Can do.

(Modification 1)
As a modification of the second embodiment, as shown in FIG. 7, the first charged body 13 can be disposed in a portion of the belt 120 exposed from the tire resin body 110 to the hollow portion 300. The first charged body 13 is bonded to a belt 120 as the first electrode 11. In this configuration, as the tire 100 is deformed, the first charged body 13 and the second charged body 14 repeat contact and separation.

  Although any material can be selected for the first charged body 13, as shown in FIG. 8, a tire resin body 110 that is a component of the tire 100 can be used as the first charged body 13. According to this, the power generation device 10 can be configured without exposing the belt 120 to the hollow portion 300 of the tire 100 as in the above example. In other words, the power generation device 10 can be configured simply by fixing the second electrode structure 16 to the inner wall of the tire 100 by the fixing portion 17.

(Modification 2)
Further, in addition to using the belt 120 in the tire 100 also as the first electrode 11 in the power generation device 10, the tire resin body 110 also serves as the second charging body 14 in the power generation device 10 as shown in FIG. 9. It can also be configured.

  In this configuration, a portion of the tire resin body 110 closer to the hollow portion 300 than the belt 120 in which the power generation device 10 is configured is separated from the belt 120. And the 2nd electrode 12 is bonded together by the hollow part 300 side of the tire resin body 110 which peeled. Thereby, the peeled part of the tire resin body 110 can be freely deformed. For this reason, with deformation of the tire 100, the belt 120 as the first electrode 11 and the tire resin body 110 as the second charged body 14 repeat contact and separation. Thereby, electric power generation can be performed similarly to 1st Embodiment.

  In this modification, the configuration in which the first charging body 13 is not provided on the surface of the belt 120 facing the second charging body 14 is shown, but a charging body made of a material different from that of the tire resin body 110 is disposed. You can also.

(Third embodiment)
In this embodiment, as shown in FIG. 10, an example in which the belt 120 has a two-layer structure of a first belt 120a and a second belt 120b inside the tire resin body 110 will be described. Since the belt 120 has a two-layer structure, in the power generation device 10, the first belt 120 a serves also as the first electrode 11 in the power generation device 10, and the second belt 120 b serves as the second electrode 13. It can be set as the structure which combines.

  In this configuration, a part of the tire resin body 110 located between the first belt 120a and the second belt 120b is removed, so that the belt 120b can be displaced relative to the belt 120a. Yes. That is, with the deformation of the tire 100, the gap AG is generated or disappears between the belt 120a and the belt 120b. In the present embodiment, the first charged body 13 is formed on the surface of the first belt 120a as the first electrode 11 that faces the second belt 120b. For this reason, with the deformation of the tire 100, the first charged body 13 and the second belt 120b as the second electrode 12 repeat contact and separation.

  In the above example, the first charging body 13 is formed on the surface of the first belt 120a facing the second belt 120b. However, the second belt 120b as the second electrode 12 is charged. A body may be provided and this may be used as the second charged body 14.

  In the above example, the example in which the first charged body 13 is formed separately from the components of the tire 100 has been shown. However, as shown in FIG. 11, the first charged body 13 is also used as the tire resin body 110. Also good. Alternatively, the tire resin body 110 may be bonded to the second belt 120b so as to serve as the second charged body 14 as well.

(Fourth embodiment)
In each of the above-described embodiments, the example in which the power generation device 10 is formed on the sidewall portion 100C has been described. The number of installations is also arbitrary. As shown in FIG. 12, two power generation apparatuses 10 in the present embodiment are arranged so as to be point-symmetric with respect to the center of gravity P of the tire 100, and constitute a tire assembly together with the tire 100.

  In the present embodiment, a weight portion 500 is installed inside the tire 100 in order to keep the right and left balance of the tire assembly. Two weight portions 500 are also arranged so as to be point-symmetric with respect to the center of gravity P of the tire 100. In this configuration, the center of gravity of the system including the tire 100, the two power generation devices 10, and the two weight portions is positioned on the rotation axis L of the tire 100. For this reason, the electric power generation device 10 can be installed inside the tire 100 without impairing the rotational performance of the tire 100.

  In addition, since the weight part 500 has a role which adjusts the gravity center of the whole tire assembly, what kind of thing may be used as long as there is no big difference with the mass of the electric power generation apparatus 10. FIG. The electronic circuit 400 may be replaced with the weight portion 500, or a simple metal lump.

(Fifth embodiment)
The autonomous power generation system in each of the above-described embodiments has been shown as an example configured from the power generation device 10 and the electronic circuit 400. In the present embodiment, as shown in FIG. 14, the autonomous power generation system includes an electronic control device 600 in addition to these elements. The electronic control device 600 is an engine ECU, for example, and uses information on air pressure obtained from the pressure sensor 410 for vehicle control, or displays information on air pressure to the driver of the vehicle.

  The electronic control device 600 in this embodiment includes a receiver 610 and a counter 620.

  The receiver 610 receives a signal wirelessly transmitted by the wireless device 420 in the electronic circuit 400. This signal is information on the air pressure detected by the pressure sensor 410 as an electronic device. That is, the pressure value inside the tire 100 at a certain time detected by the pressure sensor 410 is transmitted to the receiver 610 via the wireless device 420.

  The counter 620 counts the number of times the signal received by the receiver 610 is received.

  Further, the electronic circuit 400 in the present embodiment includes a potential difference detection unit 450 and a comparator 460 in addition to the configuration in the first embodiment.

  The potential difference detection unit 450 detects a voltage (potential difference V) between the first electrode 11 and the second electrode 12 that is generated due to deformation of the tire 100.

  The comparator 460 compares the potential difference V between the first electrode 11 and the second electrode 12 detected by the potential difference detection unit 450 with a predetermined threshold voltage Vref. The comparator 460 outputs a trigger signal to the pressure sensor 410 and the wireless device 420 under the condition of V> Vref.

  When the trigger signal is input, the pressure sensor 410 acquires air pressure information and outputs the signal to the wireless device 420. The radio 420 transmits a signal including information related to air pressure to the receiver 610.

  That is, the pressure sensor 410 outputs a signal including air pressure information every time the voltage V generated according to the deformation of the tire 100 exceeds the predetermined threshold voltage Vref. Then, every time the voltage V exceeds the threshold voltage Vref, the wireless device 420 wirelessly transmits the signal to the receiver 610.

  Then, as shown in FIG. 15, the electronic control unit 600 calculates the rotation speed of the tire 100 based on the number of receptions n of the signal counted by the counter 620 and the time t required for the counting. Specifically, the rotation speed of the tire 100 is calculated by n / t.

  Thus, in the autonomous power generation system according to the present embodiment, the number of rotations of the tire 100 can be measured using the number of air pressure signals acquired by the pressure sensor 410 without using a sensor related to the number of rotations. .

(Modification 3)
In the fifth embodiment, the example in which the information on the air pressure acquired by the pressure sensor 410 as an electronic device is used as the signal transmitted from the wireless device 420 to the receiver 610 has been described. Physical quantities are not always necessary.

  For example, every time the voltage V generated according to the deformation of the tire 100 exceeds a predetermined threshold voltage Vref, the electronic device outputs a signal that reports only information indicating V> Vref. Then, every time the voltage V exceeds the threshold voltage Vref, the wireless device 420 wirelessly transmits the signal to the receiver 610.

  In such a configuration, the signal transmitted from the wireless device 420 to the receiver 610 does not include physical quantity information, but the counter 620 in the electronic control device 600 can count the number of signal receptions n. The time t required for counting can also be measured. Therefore, the electronic control unit 600 can calculate the rotation speed of the tire 100.

(Sixth embodiment)
In the fifth embodiment and its modification (Modification 3), it is preferable that the power generation device 10 and a plurality of electronic circuits 400 connected to the power generation device 10 are formed at equal intervals.

  Specifically, as shown in FIG. 16, the power generation device 10 and 48 electronic circuits 400 connected to the power generation device 10 are formed along the rotation direction of the tire 100, respectively.

  According to this, 48 pulse signals are input to the electronic control device 600 while the tire 100 makes one rotation. Therefore, for example, even when some signals are not transmitted due to a bad road or the like, the pulse period of the signals, in other words, the rotation speed of the tire 100 can be calculated as an average value of 48 pulses. . Therefore, the calculation accuracy of the rotational speed can be improved.

  Also in the conventional rotational speed detection method using the rotational speed sensor, the number of pulses transmitted from the rotational speed sensor to the electronic control device is 48, and the power generator 10 and the electronic circuit connected to the power generator 10 If the number of 400 is set to 48, the conventional mechanism for detecting the rotational speed of the electronic control device can be used as it is.

(Other embodiments)
The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In the first embodiment, the second embodiment, and the first modification thereof (FIGS. 3 to 8), the configuration having the second charged body 14 has been shown. However, the first electrode structure 15 has the first charged body 13. If it is a structure, the 2nd charged body 14 does not necessarily need to be formed. In the configuration in which the second charged body 14 is not formed, electric power can be obtained by the first charged body 13 and the second electrode 12 repeating contact and separation from each other.

  Moreover, the material of the 1st electrode 11, the 2nd electrode 12, the 1st charged body 13, and the 2nd charged body 14 can each be selected arbitrarily. Any combination of repeating contact and separation with each other as long as it generates static electricity may be used.

  As shown in FIG. 13, when the tire 100 is composed of a plurality of tire resin bodies 110a and 110b made of different materials, the first tire resin body 110a is also used as the first charged body 13, The second charged body 14 may be used also by the second tire resin body 110b.

  Moreover, in each above-mentioned embodiment, although the pressure sensor 410 which detects the air pressure of the tire 100 was illustrated as an electronic device, it is not limited to this example. The physical quantity to be detected by the electronic device is arbitrary. For example, the electronic device may be a temperature sensor that detects the temperature inside the tire 100 or the temperature of the tire 100 itself.

  In each of the above-described embodiments, the configuration in which the electronic circuit 400 includes the battery 430 has been described. However, since the power generated by the power generation device 10 is also supplied to the electronic device, the battery 430 is not necessarily required.

DESCRIPTION OF SYMBOLS 10 ... Electric power generation apparatus 11 ... 1st electrode, 12 ... 2nd electrode, 13 ... 1st charged body, 14 ... 2nd charged body 17 ... Fixed part 100 ... Tire 110 ... Tire resin body, 120 ... Belt, 130 ... Carcass , 140 ... Bead 200 ... Wheel rim 400 ... Electronic circuit 500 ... Weight part 600 ... Electronic control unit

Claims (17)

A power generator that is assembled inside a tire (100) and generates electric power from the mechanical energy of the rotating tire,
A first electrode structure (15) having a first electrode (11) and a second electrode structure (16) having a second electrode (12) as a pair of opposing electrode structures (15, 16);
A fixing portion (17) for fixing the first electrode structure and the second electrode structure so that a distance between the first electrode structure and the second electrode structure is variable;
With
At least one of the first electrode structure and the second electrode structure has a charged body (13, 14) for generating static electricity on the facing surface side,
The first electrode structure is fixed to the tire,
The second electrode structure is movable relative to the first electrode structure;
According to the deformation of the tire, the charged body generates static electricity by coming into contact with the opposing electrode structure,
A voltage is generated between the first electrode and the second electrode by increasing a facing distance between the first electrode structure and the second electrode structure according to deformation of the tire. A power generator. The tire includes a tire resin body (110) that deforms in contact with the ground, and a belt (120) for reinforcing the tire resin therein.
2. The power generation device according to claim 1, wherein the first electrode structure is embedded and disposed in the tire resin body such that the belt serves as the first electrode.   The electric power generation according to claim 2, wherein the first electrode structure includes a first charged body (13) as the charged body, and the first charged body corresponds to the tire resin body. apparatus.   The second electrode structure includes a second charged body (14) as the charged body, and the second charged body corresponds to the tire resin body. The electric power generation apparatus of description. A plurality of the belts;
The said 2nd electrode structure is embedded and arrange | positioned inside the said tire so that the said belt different from the said belt corresponding to the said 1st electrode may become the said 2nd electrode, It is characterized by the above-mentioned. The electric power generator of any one of 2-4.   The power generation device according to claim 5, wherein the charged body corresponds to the tire resin body. It is arranged in the sidewall part (100C) in the tire,
The power generation device according to claim 1, wherein a facing direction of the first electrode and the second electrode is a normal direction on an inner wall of the sidewall portion. The power generation device (10) according to any one of claims 1 to 7,
A tire assembly comprising: a tire (100) on which the power generation device is disposed. A weight portion (500) that is fixed to the tire and moves with the power generation device according to the rotation of the tire;
The tire assembly according to claim 8, wherein a center of gravity of a system including the tire, the power generation device, and the weight portion is located on a rotation axis (L) of the tire. The power generation device (10) according to any one of claims 1 to 7, which generates electric power from mechanical energy of a tire;
A battery (430) for accumulating power generated by the power generation device;
An electronic device (410) that receives power from the battery and outputs a predetermined signal to the outside;
An autonomous power generation system comprising: a radio (420) that wirelessly transmits the signal output from the electronic device to the outside of the tire.   11. The autonomous power generation system according to claim 10, wherein the electronic device is a sensor that detects a physical quantity related to the tire, and the signal is information related to the physical quantity.   The autonomous power generation system according to claim 11, wherein the physical quantity is an air pressure inside the tire or a temperature inside the tire or the tire. An electronic control unit that is provided outside and includes a receiver that receives the signal and a counter that counts the number of times the signal is received;
The electronic device outputs the signal every time the voltage generated according to the deformation of the tire exceeds a predetermined threshold voltage,
The radio device wirelessly transmits the signal output by the electronic device to the receiver each time the voltage exceeds the threshold voltage,
The autonomous control according to any one of claims 10 to 12, wherein the electronic control unit calculates the number of rotations of the tire based on the number of receptions counted by the counter and the counted time. Power generation system. The power generation device (10) according to any one of claims 1 to 7, which generates electric power from mechanical energy of a tire;
An electronic device (410) that is supplied with power from the power generation device and outputs a predetermined signal to the outside;
A radio (420) for wirelessly transmitting the signal output from the electronic device to the outside of the tire;
An electronic control unit that is provided outside and has a receiver that receives the signal, and a counter that counts the number of times the signal has been received,
The electronic device outputs the signal every time the voltage supplied in accordance with the deformation of the tire exceeds a predetermined threshold voltage,
The radio device wirelessly transmits the signal output by the electronic device to the receiver each time the voltage exceeds the threshold voltage,
The said electronic control part calculates the rotation speed of the said tire based on the frequency | count of reception counted by the said counter, and the counted time, The autonomous power generation system characterized by the above-mentioned.   15. The autonomous power generation system according to claim 14, wherein the electronic device is a sensor that detects a physical quantity related to the tire, and the signal is information related to the physical quantity.   The autonomous power generation system according to claim 15, wherein the physical quantity is an air pressure inside the tire or a temperature inside the tire or the tire.   The autonomous power generation system according to any one of claims 11 to 16, wherein a plurality of the power generation device and the electronic device are each formed at equal intervals along a rotation direction of the tire.

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