JP5362398B2 - In-tire power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a generation device in a tire, capable of obtaining a high electric power. <P>SOLUTION: The generation device includes a power generation magnet 6 so provided as to reciprocate linearly according to change in the centrifugal force applied to a tire during vehicle travel, a yoke 7 which allows a magnetic flux generated by the power generation magnet to pass, and a coil 8 wound on the yoke. One side of the power generation magnet in the direction across the direction of linear reciprocation is magnetized to be one pole while the other side in the direction across the direction of linear reciprocation is magnetized to be the other pole. The yoke includes a magnetic flux inlet 7b for taking in the magnetic flux from one pole of the power generation magnet and a magnetic flux outlet part 7c for sending the magnetic flux to the other pole of the power generation magnet. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an in-tire power generator capable of obtaining high power.

  When a device with a sensor and radio such as a TPMS (tire pressure monitoring system) that detects the temperature and pressure in the tire is installed in the tire chamber and tire monitoring is performed, power is supplied to the device. An in-tire power generation device is known (see Patent Document 1).

JP 2000-278923 A

However, the conventional in-tire power generator has a problem that high power cannot be obtained.
The present invention has been made in view of the above problems, and provides an in-tire power generator that can obtain high power.

According to the in-tire power generation device according to the present invention, in the power generation device mounted in the tire chamber, a power generation magnet provided so as to be capable of linear reciprocation according to a change in centrifugal force applied to the tire during vehicle travel, The power generation magnet includes a yoke through which the magnetic flux generated by the power generation magnet passes and a coil wound around the yoke. The power generation magnet is magnetized on one side in a direction intersecting the linear reciprocation direction and linearly reciprocated. The other side in the direction crossing the moving direction is magnetized to the other pole, and the yoke has a magnetic flux inlet part that takes in the magnetic flux from one pole of the power generating magnet and a magnetic flux outlet part that sends the magnetic flux to the other pole of the power generating magnet. Since the magnetic flux density is increased, a high voltage can be generated and high power can be obtained.
The power generating magnet is configured by adhering a plurality of unit magnets in a direction along the linear reciprocating direction, and the unit magnets are bonded to each other with the portions magnetized to have different polarities. Every time one unit magnet passes the side of the yoke in the direction of linear reciprocation, the direction of the magnetic flux passing through the yoke is reversed, so the reversal speed of the magnetic flux is increased and a high voltage can be generated.
The magnetic flux inlet portion and the magnetic flux outlet portion of the yoke include a facing surface that faces the circumferential surface along the linear reciprocating movement direction of the power generating magnet, and the facing surface is in a direction along the circumferential direction of the circumferential surface of the power generating magnet. Since the length is longer than the length in the direction along the linear reciprocating direction of the power generation magnet, the magnetic flux from the power generation magnet can be efficiently taken into the yoke, and a high voltage can be generated.
The cross-sectional area S of the coil winding portion around which the coil of the yoke was wound was made to satisfy the following conditions.
φ <S × Bm <1.2 × φ
Where Bm is the maximum saturation magnetic flux density of the yoke, φ is the total magnetic flux of the power generating magnet.
That is, by setting φ <S × Bm, all the magnetic flux generated by the power generation magnet can be passed through the yoke, and by setting S × Bm <1.2 × φ, the overall length of the coil is shortened. become able to.
Since a rectangular wire having a rectangular cross section is used as the winding of the coil, the winding resistance can be reduced and the number of turns can be increased, and the winding density can be improved, thereby increasing the power generation efficiency.
A base having a base surface orthogonal to the linear reciprocation direction of the power generation magnet, a guide rod provided from the base surface for guiding the linear reciprocation of the power generation magnet, one end fixed to the base surface and the other end A coil spring as a repelling means fixed to the lower surface of the power generation magnet facing the base surface, and the coil spring causes the power generation magnet to perform linear reciprocation within a predetermined linear reciprocation range, and for power generation Since the collision between the magnet and the base surface was prevented, the power generating magnet reciprocated linearly with high accuracy by the guide rod, and since the coil spring was provided, the power generating magnet was straightened by turning ON / OFF the centrifugal force of the tire. Since it can be reciprocated, a high voltage can be generated efficiently.
Since the opposing surface of the yoke is provided at a position that coincides with the center position of the length of the power generation magnet in the linear reciprocation direction when the car is suspended at 30 km / h and the coil spring is suspended, the power generation magnet is In this case, simple vibration is repeated in the direction of linear reciprocation around the arcuate surface of the yoke, and power can be generated efficiently even at low speeds.
A base having a base surface orthogonal to the linear reciprocating direction of the power generating magnet, a guide bar provided from the base surface for guiding the linear reciprocating movement of the power generating magnet, and an end opposite to the base surface of the guide bar And a rebounding magnet that is fixed to the base surface and repels the power generation magnet, and is provided between the power generation magnet and the repulsion magnet. The power generating magnets are attached to the guide rods so as to be non-rotatable around the guide rods so that the surfaces facing each other are maintained at the same polarity. Since the repulsion magnet is provided, the power generation magnet can be linearly reciprocated by turning on / off the centrifugal force of the tire, so that a high voltage can be generated efficiently.

The figure which shows the electric power generation apparatus in a tire (form 1). Sectional drawing (form 1) of the magnet for electric power generation. The top view which shows the relationship between the magnet for an electric power generation and an arcuate surface (form 1). Sectional drawing which shows the relationship between the magnet for electric power generation and an arcuate surface (form 1). The figure which shows the electric power generation apparatus in a tire (form 2). The graph which shows the electric power generation condition by the electric power generation apparatus in a tire (Example). The graph which shows the change of the electrical storage amount at the time of driving | running | working 30 km / h (Example).

Form 1
As shown in FIG. 1, the in-tire power generation device 1 attached to the tire chamber according to the first embodiment includes a base 2, a guide rod 3, a linear bearing 4, a repulsive means 5, and a tire during vehicle travel. A power generation magnet 6 provided so as to be capable of linear reciprocation according to a change in applied centrifugal force, a yoke (soft magnetic material) 7 through which a magnetic flux generated by the power generation magnet 6 passes, and a coil 8 wound around the yoke 7 With. Both ends of the coil 8 are connected to the rectifier circuit 25.

The base 2 is formed by a disc. The guide bar 3 that guides the movement of the power generation magnet 6 is formed of a round bar. The guide bar 3 is provided so as to extend in a direction orthogonal to the base surface 18 from the center of the base surface 18 formed by one of the circular surfaces of the disk forming the base 2. That is, the base 2 having the base surface 18 orthogonal to the linear reciprocating direction of the power generation magnet 6 and one end fixed to the base surface 18 and the other end penetrating the power generation magnet 6 to linearly reciprocate the power generation magnet 6. And a guide bar 3 for guiding the movement.
The base 2 and the guide bar 3 may be integrally formed, or may be formed by connecting individual members formed separately from each other.

  Although not shown, the linear bearing 4 is formed by an outer cylinder, a holding cylinder provided inside the outer cylinder, and a large number of balls provided inside the holding cylinder. A plurality of grooves extending in the direction along the central axis of the cylinder are formed on the inner surface of the holding cylinder at predetermined intervals in the circumferential direction, and the plurality of balls are circulated infinitely along the groove. It is structured to exercise. That is, the linear bearing 4 is attached to the guide rod 3 so that the guide rod 3 penetrates the cylindrical hole of the holding cylinder, and the ball exposed from the groove of the holding cylinder of the linear bearing 4 and the outer peripheral surface of the guide rod 3 slide. By moving, the outer peripheral surface of the guide bar 3 and the ball can make a relative movement with low rolling friction while rolling. This rolling friction coefficient μ is 0.005.

  The power generation magnet 6 is a disc-shaped magnet having a center hole 11 fitted into the outer peripheral surface 23 of the cylinder of the linear bearing 4 at the center of a circle. The center hole 11 of the power generation magnet 6 is fitted into the outer peripheral surface 23 of the cylinder of the linear bearing 4, and the power generation magnet 6 is fixed to the linear bearing 4 so as to be concentric with the linear bearing 4. Thus, the power generation magnet 6 is configured to be capable of linear reciprocation on the guide rod 3 via the linear bearing 4 in the extending direction of the guide rod 3 in accordance with a change in centrifugal force applied to the tire during vehicle travel. In this case, since the linear bearing 4 is provided, the frictional resistance with the guide rod 3 can be reduced, and the power generating magnet 6 performs linear reciprocation with high accuracy.

In the magnet 6 for power generation, a plurality of disk-shaped unit magnets 15 having a center hole 11 fitted into the outer peripheral surface 23 of the cylinder of the linear bearing 4 at the center of a circle are in a direction along a linear reciprocation direction (guide rod). 3 (direction along 3). As shown in FIG. 1, the power generation magnet 6 has a four-layer structure in which, for example, the circular surfaces of four unit magnets 15 are bonded to each other.
The unit magnet 15 is configured such that one side in the direction intersecting the linear reciprocating direction of the power generation magnet 6 is magnetized to one pole and the other side in the direction intersecting the linear reciprocating direction is magnetized to the other pole. It is. Specifically, in the unit magnet 15, one semicircular portion 15a of the disk on one side in the direction orthogonal to the linear reciprocating direction of the power generation magnet 6 is magnetized to the “N” pole, and the power generation magnet The other semicircular portion 15b of the disc on the other side in the direction orthogonal to the linear reciprocating movement direction 6 is magnetized to the “S” pole.
As shown in FIG. 2, the semicircular surfaces 15x; 15y of the semicircular portions magnetized with different polarities are bonded to each other between the unit magnets 15.

  The repulsion means 5 is formed of an elastic body such as a coil spring 5A, for example. One end of the coil spring 5A is connected to the base surface 18, and the other end of the coil spring 5A is connected to the lower surface 6x of the power generation magnet 6, whereby the power generation magnet 6 and the base 2 are connected via the coil spring 5A. Is done. Therefore, the coil spring 5 </ b> A expands and contracts due to the centrifugal force when the vehicle travels, so that the power generation magnet 6 can be linearly reciprocated along the guide rod 3. That is, the coil spring 5A causes the power generation magnet 6 to perform linear reciprocation within a predetermined linear reciprocation range, and when the centrifugal force is applied to the power generation magnet 6, the lower surface 6x of the power generation magnet 6 and the base The collision with the surface 18 is prevented.

The yoke 7 includes a coil winding portion 7 a around which a coil is wound, a magnetic flux inlet portion 7 b that takes in a magnetic flux from one pole of each unit magnet 15 of the power generation magnet 6, and the other pole of each unit magnet 15 of the power generation magnet 6. And a magnetic flux outlet 7c that sends the magnetic flux to the unit magnet 15, and forms a magnetic flux passage that takes in the magnetic flux from one pole of each unit magnet 15 constituting the power generation magnet 6 and sends the magnetic flux to the other pole of each unit magnet 15.
The coil winding portion 7a is formed in a semicircular arc shape in which the ring is cut in half along the center line of the hole of the ring. The magnetic flux inlet portion 7b is provided at one end of the coil winding portion 7a, and the magnetic flux outlet portion 7c is provided at the other end of the coil winding portion 7a. The yoke 7 is fixed to the upper ends of the columns 71; 72 whose lower ends are fixed to the base.
As shown in FIG. 2, one support column 71 is provided so as to face the center in the circumferential direction of the semicircular surface 61 of one semicircular portion of the power generation magnet 6, and the other support column 72 is formed of the power generation magnet 6. It is provided so as to face the center in the circumferential direction of the semicircular surface 62 of the other semicircular portion. The coil winding portion 7 a has a semicircular arc facing the circumferential surface of the power generation magnet 6, the lower end of one end and the upper end of one strut 71 are fixed with an adhesive or the like, and the lower end of the other end and the other strut 72 The upper end is fixed with an adhesive or the like.
The magnetic flux inlet portion 7 b and the magnetic flux outlet portion 7 c include a facing surface that faces the circumferential surface along the linear reciprocating movement direction of the power generation magnet 6, and the facing surface is along the circumferential direction of the circumferential surface of the power generation magnet 6. The length in the direction is longer than the length in the direction along the linear reciprocating direction of the power generation magnet 6. Specifically, as shown in FIG. 3, the magnetic flux inlet portion 7 b protrudes from one end of the coil winding portion 7 a fixed to the upper end of one support 71, and is a half circumferential surface of one semicircular portion 15 a of the unit magnet 15. An arcuate surface 75 is provided as an opposing surface that extends along the circumferential direction of 15d and faces the half circumferential surface 15d. The magnetic flux outlet portion 7c protrudes from the other end of the coil winding portion 7a fixed to the upper end of the other support column 72 and extends along the circumferential direction of the semicircular surface 15e of the other semicircular portion 15b of the unit magnet 15. An arcuate surface 76 is provided as an opposing surface facing the half circumferential surface 15e.

  The coil 8 is configured to be wound N times (for example, 1000 times) spirally around the outer peripheral surface of the coil winding portion 7a of the yoke 7 from one end side to the other end side of the coil winding portion 7a.

In the in-tire power generator 1 configured as described above, the other circular surface of the base 2 is fixed at a position corresponding to the back surface of the tread surface, for example, in the tire chamber. Then, when the vehicle is driven, the power generating magnet 6 reciprocates linearly in the extending direction of the guide rod 3 due to the fluctuation of the centrifugal force having the highest energy due to the vibration in the tire. The centrifugal force F in the tire F = m × V ² / r (where m is the mass of the power generator 1 in the tire, V is the wheel speed, and r is the tire radius) is determined by V ² / r except at the time of ground contact. Sometimes 0. Due to this centrifugal force, the coil spring 5 </ b> A repels, and the power generation magnet 6 reciprocates linearly in the extending direction of the guide rod 3. Each time the unit magnet 15 of the power generating magnet 6 passes the arcuate surfaces 75; 76 of the yoke 7 in the vertical direction, the direction of the magnetic flux passing through the yoke 7 is reversed, and the magnetic flux crosses the coil 8 every time. A voltage is generated. This voltage is charged into the charging circuit 26 through the rectifying circuit 25 and supplied to the device 27.
In addition, whenever the magnetic pole of the unit magnet 15 which passes the side of the arcuate surface 75; 76 of the both ends of the yoke 7 in the up-down direction changes, the arcuate surface 75; 76 becomes a magnetic flux entrance part or a magnetic flux exit part.

  According to the first aspect, the power generation magnet 6 is composed of the plurality of unit magnets 15 that are laminated in the direction along the bar of the guide bar 3 by bonding the different poles to each other. Since the direction of the magnetic flux passing through the yoke 7 is reversed every time 15 passes the arcuate surfaces 75; 76 of the yoke 7 in the linear reciprocating direction, the reversal speed of the magnetic flux is increased. Since the speed at which the magnetic flux is reversed is proportional to the magnitude of the voltage generated at both ends of the coil 8, the in-tire power generator 1 that generates a high voltage can be provided.

  The speed at which the magnetic flux is reversed becomes faster as the thickness a of the unit magnet 15 and the thickness b of the arcuate surfaces 75; 76 in the direction along the extending direction of the guide rod 3 are smaller. As shown in FIG. 2, it is desirable to reduce the thickness a of the unit magnet 15 and the thickness b of the arcuate surfaces 75 and 76 of the yoke 7.

  Since the yoke 7 has the arcuate surfaces 75 and 76 that function as the magnetic flux inlet portion 7b and the magnetic flux outlet portion 7c, the magnetic flux from the unit magnet 15 can be efficiently taken into the yoke 7 and a high voltage can be generated.

  According to the first aspect, since the power generation magnet 6 is held by the linear bearing 4 and configured to be linearly reciprocable along the guide rod 3, the frictional resistance when the power generation magnet 6 is moved by the linear bearing 4. Since the power generation magnet 6 reciprocates linearly with high accuracy by the guide rod 3, the power generation magnet 6 smoothly reciprocates linearly and can generate high voltage efficiently. The apparatus 1 can be provided.

  According to the first aspect, since the coil spring 5A as the repulsion means 5 is provided, the power generation magnet 6 can be linearly reciprocated by ON / OFF of the centrifugal force of the tire, and a high voltage can be generated efficiently.

  In the first aspect, the position of the arcuate surfaces 75; 76 of the yoke 7 from the base surface 18 is preferably the length of the generator magnet 6 in the linear reciprocating direction when the vehicle is suspended at 30 km / h and the coil spring 5A is suspended. It is provided at a position that coincides with the center position. As a result, the power generation magnet 6 repeats simple vibrations in the direction of linear reciprocation around the arcuate surfaces 75; 76 of the yoke 7 at low speed, so that power can be generated efficiently even at low speed.

  In the first embodiment, preferably, as shown in FIG. 4, the shortest distance X between the half circumferential surface 15d; 15e of the circle of the unit magnet 15 (power generation magnet 6) and the arcuate surface 75; The magnet 15 (power generation magnet 6) is formed to have a diameter of about 10% or less of the outer diameter of the circle. Thereby, leakage magnetic flux can be reduced and a high voltage can be generated.

In the form 1, it is preferable that the cross-sectional area S of the coil winding portion 7a around which the coil 8 of the yoke 7 is wound satisfies the following condition.
φ <S × Bm <1.2 × φ
Where Bm is the maximum saturation magnetic flux density of the yoke, φ is the total magnetic flux of the power generating magnet.
Thus, by setting φ <S × Bm, all the magnetic flux generated by the power generation magnet can be passed through the yoke. By setting S × Bm <1.2 × φ, the total length of the coil Can be shortened. Therefore, the apparatus can be miniaturized and the power generation efficiency is increased.

  In the first embodiment, a rectangular wire having a rectangular cross section is preferably used as the winding of the coil 8. As a result, the winding resistance can be reduced and the number of turns can be increased, and the winding density can be improved, thus increasing the power generation efficiency.

  In the first embodiment, the ball of the linear bearing 4 is preferably formed of a non-magnetic material such as ceramic or resin. As a result, the movement of the ball can be prevented from being hindered by the magnetic force of the power generation magnet 6, and the power generation magnet 6 can be smoothly reciprocated linearly.

  In the first embodiment, the guide rod 3 is preferably made of a nonmagnetic material. Accordingly, the guide rod 3 and the power generation magnet 6 can be prevented from attracting each other, and the power generation magnet 6 can be smoothly reciprocated linearly.

  In the first embodiment, the guide rod 3 is preferably made of a nonconductive material. Thereby, the eddy current which generate | occur | produces in the guide rod 3 can be eliminated, and the mechanical loss by the guide rod 3 can be eliminated.

  In the first embodiment, the power generating magnet 6 is preferably formed of a neodymium magnet having a high residual magnetic flux density. Thereby, a large repulsive force and a stable high voltage can be obtained.

Example of Form 1 Tire size: 225 / 55R17 was used.
The magnet 6 for power generation was prepared by laminating four unit magnets 15 formed of a disc-shaped neodymium magnet having a thickness a of 1.25 mm and φ10 mm.
The shortest distance X between the half circumferential surface 15d; 15e of the circle of the unit magnet 15 (the power generation magnet 6) and the arcuate surface 75; 76 of the yoke 7 was 0.2 mm.
The coil 8 was wound with a wire diameter of 0.2 mm, a total length of 11.7 m, a resistance of 5Ω, and 1000 turns.
• Linear bearings with non-magnetic ceramic balls were used.
-The running speed was set to 30 km / h, and the vehicle was run until the stored voltage stabilized from 0V.
-The power generation amount (W = V ² / R) was calculated from the stable voltage and the load of the device (R = 500Ω).
A graph of the voltage generated by the example is shown in FIG. FIG. 7 shows the state of stored voltage during traveling.
As can be seen from FIG. 7, 23 mW was obtained at 30 km / h.

Form 2
Instead of the coil spring 5A, a repulsion magnet 5B serving as a repulsion means 5 acting as a magnetic spring and repelling the power generation magnet 6 was used.
As shown in FIG. 5, a preventing portion 80 provided at the other end of the guide rod 3 to prevent the generator magnet 6 from coming off from the guide rod 3, and the generator magnet 6 repelled by being fixed to the base surface 18. And a repulsion magnet 5B.
The repulsion magnet 5 </ b> B is formed in a disc shape having a center hole 81 through which the guide rod 3 passes, and the disc surface 82 and the base surface 18 are bonded to the center hole 81 through the guide rod 3. The outer diameter of the disk of the repulsion magnet 5B is smaller than the outer diameter of the disk of the base 2. The semicircular surfaces of the semicircular portions of the power generation magnet 6 and the repulsion magnet 5B that face each other are formed to have the same polarity, so that when the power generation magnet 6 approaches the repulsion magnet 5B, the power generation magnet 6 Since the repulsion magnet 5B repels and moves away from the repulsion magnet 5B, collision between the power generation magnet 6 and the repulsion magnet 5B is prevented when a centrifugal force is applied to the power generation magnet 6.
When the repulsion magnet 5B is used, in order to prevent the power generation magnet 6 and the repulsion magnet 5B from sticking to each other, the mutually facing surfaces of the power generation magnet 6 and the repulsion magnet 5B are maintained in the same polarity. Thus, a rotation preventing structure is provided in which the power generating magnet 6 is attached to the guide rod 3 so as not to rotate about the guide rod 3. For example, as shown in FIG. 5, the anti-rotation structure is formed with a non-rotation groove 90 extending along the axial direction of the guide rod 3 in the guide rod 3, and the anti-rotation structure is formed in the center hole 11 of the power generation magnet 6. An engagement piece 91 that fits into the groove 90 may be provided.

  Although not shown, if the power generation magnet 6 is held by the linear bearing 4, the surfaces of the repulsion magnet 5B and the power generation magnet 6 facing each other can be more accurately kept parallel to each other, so that the maximum repulsive force can be obtained. it can. In this case, by forming the linear bearing 4 from a non-magnetic material, it is possible to prevent attraction between the repulsion magnet 5B and the power generation magnet 6, and the repulsion force by the repulsion magnet 5B can be maximized. Thus, it can be prevented that the repulsion magnet 5B and the power generation magnet 6 come into contact with each other and the power generation magnet 6 does not cross the arcuate surfaces 75; 76 of the yoke 7 and no power is generated.

Form 3
In the case of the form 2, the power generation magnet 6 is a circle of the unit magnet 15 positioned on the side farther from the repulsion magnet 5B in the thickness of the disk of the unit magnet 15 positioned closer to the repulsion magnet 5B. A thing thicker than the thickness of the plate, for example, about 5/3 is used. Thereby, since the repulsive force which acts between the magnet 6 for electric power generation and the magnet 5B for repulsion becomes large, the tread surface located in the back side of the inner surface of the tire in which the in-tire electric power generating apparatus 1 is attached is earth | grounded. Time (when the centrifugal force is OFF), the potential energy can be maximized, and when the centrifugal force is generated, the power generation magnet 6 can increase the speed of crossing the arcuate surfaces 75; 76 of the yoke 7, so that a high voltage can be generated. become.

  According to the in-tire power generation device 1 of the present invention, in order to detect the temperature and pressure tire information in the tire, for example, the pressure applied to the tire, the slipperiness of the road surface, and continuously transmit the dynamic state of these tires. Power can be stably supplied to devices that require high power.

  The power generation magnet 6 may be formed by one unit magnet 15.

DESCRIPTION OF SYMBOLS 1 Power generator in tire, 2 base, 3 guide rod, 5A coil spring (repulsion means), 5B repulsion magnet (repulsion means), 6 power generation magnet, 7 yoke, 8 coil,
15 unit magnets, 75; 76 arcuate surface (opposite surface), 80 omission prevention part.

Claims (8)

  In a power generation device attached to a tire chamber, a power generation magnet provided so as to be linearly reciprocable in accordance with a change in centrifugal force applied to the tire when the vehicle is traveling, and a yoke through which a magnetic flux generated by the power generation magnet passes A coil wound around a yoke, and the power generation magnet is magnetized on one pole in the direction intersecting the linear reciprocating direction and the other side in the direction intersecting the linear reciprocating direction is the other pole. And the yoke includes a magnetic flux inlet portion that takes in the magnetic flux from one pole of the power generating magnet and a magnetic flux outlet portion that sends the magnetic flux to the other pole of the power generating magnet. .   The power generation magnet is configured by adhering a plurality of unit magnets in a direction along the linear reciprocating direction, and the unit magnets are bonded to each other with magnetized portions having different polarities. The in-tire power generation device according to claim 1.   The magnetic flux inlet portion and the magnetic flux outlet portion of the yoke include a facing surface that faces the circumferential surface along the linear reciprocating movement direction of the power generating magnet, and the facing surface is in a direction along the circumferential direction of the circumferential surface of the power generating magnet. The in-tire power generator according to claim 1 or 2, wherein the length is longer than a length in a direction along a linear reciprocating direction of the power generating magnet. The in-tire power generator according to any one of claims 1 to 3, wherein the cross-sectional area S of the coil winding portion around which the coil of the yoke is wound satisfies the following condition.
φ <S × Bm <1.2 × φ
However,
Bm: Maximum saturation magnetic flux density of the yoke φ: Total magnetic flux of the magnet for power generation   The in-tire power generator according to any one of claims 1 to 4, wherein a rectangular wire having a rectangular cross section is used as a coil winding.   A base having a base surface orthogonal to the linear reciprocation direction of the power generation magnet, a guide rod provided from the base surface for guiding the linear reciprocation of the power generation magnet, one end fixed to the base surface and the other end A coil spring as a repelling means fixed to the lower surface of the power generation magnet facing the base surface, and the coil spring causes the power generation magnet to perform linear reciprocation within a predetermined linear reciprocation range, and for power generation The in-tire power generator according to any one of claims 1 to 5, wherein a collision between the magnet and the base surface is prevented.   The opposing surface of the yoke is provided at a position coinciding with the center position of the length of the power generation magnet in the linear reciprocating direction when the coil spring is suspended at a speed of 30 km / h. The in-tire power generation device described.   A base having a base surface orthogonal to the linear reciprocating direction of the power generating magnet, a guide bar provided from the base surface for guiding the linear reciprocating movement of the power generating magnet, and an end opposite to the base surface of the guide bar And a rebounding magnet that is fixed to the base surface and repels the power generation magnet, and is provided between the power generation magnet and the repulsion magnet. 6. The generator magnet according to claim 1, wherein the power generating magnets are attached to the guide rod so as to be non-rotatable around the guide rod so that the surfaces facing each other are maintained in the same polarity. In-tire power generator.

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