JP2011229237A

JP2011229237A - Power generator in tire

Info

Publication number: JP2011229237A
Application number: JP2010095132A
Authority: JP
Inventors: Akira Kobayakawa; 彰小早川
Original assignee: Bridgestone Corp
Current assignee: Bridgestone Corp
Priority date: 2010-04-16
Filing date: 2010-04-16
Publication date: 2011-11-10
Anticipated expiration: 2030-04-16
Also published as: JP5646871B2

Abstract

PROBLEM TO BE SOLVED: To provide a power generator in a tire, which is capable of obtaining a high power.SOLUTION: The power generator in a tire is to be attached in a tire air chamber and includes; a rotating body which is attached to a revolving shaft, is partially formed of magnets so as to make the rotation center and the center of gravity different from each other, and rotates in accordance with the change of force applied to the tire during running of a vehicle; and a coil part which is located between magnets facing each other of the rotating body and generates a voltage by electromagnetic induction action between the magnets and the coil part itself. The coil part includes a coil winding in which a coil is wound like a cylinder surrounding spaces which magnetic fluxes generated between mutually different magnetic poles of magnets facing each other pass. The rotating body includes a plurality of magnets arranged so as to alternate magnetic poles along a rotation direction of the rotating body and a yoke body provided on the opposite side to the side facing the coil part, of the plurality of magnets. A thickness of the yoke body in positions in which magnetic poles of the plurality of magnets of the rotating body are inverted is made thicker than that in end parts in the rotation direction of the yoke body, in a rotation axis direction.

Description

本発明は、タイヤ内発電装置に関し、特に、磁力を効率的に得られる構造を有し、高電力を得ることの可能なタイヤ内発電装置に関する。 The present invention relates to an in-tire power generation device, and more particularly to an in-tire power generation device having a structure capable of efficiently obtaining magnetic force and capable of obtaining high power.

タイヤ内の温度や圧力を検出するＴＰＭＳ(タイヤ・プレッシャー・モニタリング・システム)等のセンサ＋無線を有するデバイスをタイヤ気室内に設置してタイヤモニタリングを実施する場合に、そのデバイスに電力を供給するタイヤ内発電装置が知られている。
例えば、発電体を螺旋状に摺動させることで磁石とコイルで発電させる技術（特許文献１等参照）、回転錘を回転させて発電させる技術（特許文献２等参照）などが知られている。 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 generator is known.
For example, a technique for generating electricity with a magnet and a coil by sliding a power generation body in a spiral shape (see Patent Document 1, etc.), a technique for generating electricity by rotating a rotating weight (see Patent Document 2, etc.), and the like are known. .

しかしながら、特許文献１の技術では、発電体にかかる力の方向と発電体の螺旋摺動方向とが同一方向ではないため、発電体の摺動抵抗が大きく、発電効率が低いので、高電力を得ることができない。また、特許文献２の技術では、回転錘と発電ロータの回転力が歯車を介して伝達されるため、回転抵抗が高く、発電効率が低いので、高電力を得ることができない。 However, in the technique of Patent Document 1, since the direction of the force applied to the power generation body and the spiral sliding direction of the power generation body are not the same direction, the sliding resistance of the power generation body is large and the power generation efficiency is low. Can't get. Moreover, in the technique of patent document 2, since the rotational force of a rotary weight and an electric power generation rotor is transmitted via a gearwheel, since rotational resistance is high and electric power generation efficiency is low, high electric power cannot be obtained.

特開２０００−９２７８４号公報JP 2000-92784 A 特開２０００−２７８９２３号公報JP 2000-278923 A

本発明は、上記課題を解決するために、高電力を得ることができるタイヤ内発電装置を提供する。 In order to solve the above problems, the present invention provides an in-tire power generator capable of obtaining high power.

本発明の第１の構成として、タイヤ気室内に取付けられるタイヤ内発電装置であって、回転軸に取付けられ回転中心と重心とが異なるように一部が磁石により形成されて車両走行時のタイヤに加わる力の変化に応じて回転する回転体と、互いに対向する回転体の磁石間に位置し、当該磁石との電磁誘導作用により電圧を発生するコイル部とを備え、コイル部は、互いに対向する磁石の互いに異なる磁極間で発生する磁束が通る空間を取り囲む筒形状にコイルが巻回されたコイル巻体を備え、回転体は、回転体の回転方向に沿って磁極が交互に入れ替わるように配置した複数の磁石と、磁石のコイル部に対向する面とは反対側の面にヨーク体とを備え、回転体の複数の磁石の磁極が反転する位置のヨーク体の厚さをヨーク体の回転方向端部の厚さよりも回転軸方向に厚く設定するようにした。本発明によれば、ヨーク体の厚みを磁石の極性の変化点において最も厚くし、極性の変化点から離れるほど薄くすることにより、極性の変化点程多くの磁力線がヨーク体内を通過するため、ヨーク体外部に漏れ出す磁束が減ることで磁石から放出される磁力線が対向する回転体の磁石間の磁力を最大とし、効率的に発電することができる。
本発明の第２の構成として、ヨーク体の回転方向の厚さの分布をヨーク体の飽和磁場となるようにヨーク体の厚さを設定するようにした。本発明によれば、ヨーク体の厚さをヨーク体の固有の最大飽和密度（Ｂｍ）と等しくなるように設定することで、磁石から放出される磁力線の全てをヨーク体内に通過させることができ、磁石から放出される磁力線が一切ヨーク体から漏れることがない。また、磁石の極性の変化点からの距離に応じてヨーク体の厚さを変化させることで、ヨーク体の体積を最小に設定することができる。
本発明の第３の構成として、コイル巻体が、回転体の磁石の回転軌跡の投影部分に設けられるようにした。本発明によれば、コイル巻体の筒内を通過する磁束φの磁束密度を大きくでき、高電力を得ることができる。
本発明の第４の構成として、コイル巻体の筒の断面の外周形状と回転体の磁石の断面の外周形状とが同じ形状に形成され、回転体の回転により磁石の断面の中心線とコイル巻体の筒の断面の中心線とが一致した場合に、コイル巻体の筒の断面の外周の長さが回転体の磁石の断面の外周の長さ以下であるようにした。本発明によれば、コイル巻体の抵抗を小さくでき、発電効率が高くなる。
本発明の第５の構成として、コイル巻体を複数備え、コイル巻体毎に整流回路及び充電回路を設けるようにした。本発明によれば、充電量を多くできる。
本発明の第６の構成として、コイル部を中心に回転体の磁石が対称、かつ、対向して回転軸に固定され、回転体と回転軸とが一体に回転するように構成した。本発明によれば、コイル部に対して安定した磁界を供給できるので、発電効率を高めることができる。
本発明の第７の構成として、ヨーク体は、扇の２つの半径のなす角度が１８０°以下の扇部と扇部の要部とを備えたヨーク面板と、扇部の外周縁に沿って扇部の面と垂直をなすように設けられた磁石位置決め板と、扇部の要部に回転軸への取付孔とを備え、当該ヨーク体は、ヨーク面板と磁石位置決め板とで囲まれた扇形状の磁石設置部を形成し、磁石を磁石設置部に対応した扇形状に形成し、磁石の扇の要に回転軸の外周面に対応する湾曲切欠部を形成し、磁石設置部に設置するようにした。本発明によれば、磁石に回転軸への取付部を設けないことで、回転体がより回転しやすくなるので、コイル巻体の筒内の空間を通過する磁束φの向きが変化する速度がより速くなって、高電力を得ることができ、また、効率的な連続発電が可能となり、発電量を増加させることができる。また、磁石を偏心錘として利用したので、部品点数を削減できる。また、磁石が回転しやすくなり、高電力を得ることができるので、発電量を増加させることができる。
本発明の第８の構成として、取付孔は少なくとも１辺の直線を備えた孔に形成され、かつ、取付孔が取付けられる回転軸の部分の断面形状が孔に対応した形状に形成されるようにした。本発明によれば、回転体の磁石がコイル部を中心として対称な形状で対向した状態に維持されて回転体と回転軸とが一緒に回転可能なように、回転体の磁石を位置決めして回転軸に取付ける作業が容易となる。
本発明の第９の構成として、コイル部が、タイヤの内面にベースを介して固定されたコイル部固定部材に固定されるようにした。本発明によれば、互いに対向して回転する回転体の磁石に対するコイル部の位置を正確に維持でき、磁束φの乱れを防止できて、発電効率が高くなる。
本発明の第１０の構成として、回転軸が、タイヤの幅方向に延長するようにトレッド面の裏面に取付けられるようにした。本発明によれば、車両走行時のタイヤに加わる遠心力の変化に応じて回転体が回転しやすくなり、高電力を得ることができるので、発電量を増加させることができる。 A first configuration of the present invention is an in-tire power generation device that is mounted in a tire chamber and is mounted on a rotating shaft, a part of which is formed of a magnet so that the center of rotation and the center of gravity are different, and the tire during vehicle travel A rotating body that rotates in response to a change in force applied to the magnet, and a coil unit that is located between the magnets of the rotating body facing each other and generates a voltage by electromagnetic induction with the magnet, the coil units facing each other A coil winding body in which a coil is wound in a cylindrical shape surrounding a space through which magnetic flux generated between different magnetic poles of the magnet to pass is provided, and the rotating body is configured so that the magnetic poles are alternately switched along the rotation direction of the rotating body A yoke body is provided on the surface opposite to the surface facing the coil portion of the magnet, and the thickness of the yoke body at a position where the magnetic poles of the plurality of magnets of the rotating body are reversed is determined. End thickness in the rotation direction And to set thicker in the rotational axis direction than. According to the present invention, the thickness of the yoke body is the thickest at the polarity change point of the magnet, and the magnetic field lines pass through the yoke body as much as the polarity change point by reducing the thickness away from the polarity change point. By reducing the magnetic flux leaking to the outside of the yoke body, it is possible to maximize the magnetic force between the magnets of the rotating bodies opposed to the lines of magnetic force emitted from the magnets, and to generate power efficiently.
As a second configuration of the present invention, the thickness of the yoke body is set so that the thickness distribution in the rotation direction of the yoke body becomes the saturation magnetic field of the yoke body. According to the present invention, by setting the thickness of the yoke body to be equal to the intrinsic maximum saturation density (Bm) of the yoke body, all the lines of magnetic force emitted from the magnet can be passed through the yoke body. No magnetic field lines emitted from the magnet leak from the yoke body. Further, the volume of the yoke body can be set to the minimum by changing the thickness of the yoke body according to the distance from the change point of the polarity of the magnet.
As a third configuration of the present invention, the coil winding body is provided on the projected portion of the rotation locus of the magnet of the rotating body. According to the present invention, the magnetic flux density of the magnetic flux φ passing through the inside of the coil winding body can be increased, and high power can be obtained.
As a fourth configuration of the present invention, the outer peripheral shape of the cross section of the tube of the coil winding body and the outer peripheral shape of the cross section of the magnet of the rotating body are formed in the same shape, and the center line of the magnet cross section and the coil are rotated by the rotation of the rotating body. When the center line of the cross section of the cylinder of the wound body coincides, the length of the outer periphery of the cross section of the cylinder of the coil wound body is set to be equal to or less than the length of the outer periphery of the cross section of the magnet of the rotating body. According to the present invention, the resistance of the coil winding body can be reduced, and the power generation efficiency is increased.
As a fifth configuration of the present invention, a plurality of coil winding bodies are provided, and a rectifier circuit and a charging circuit are provided for each coil winding body. According to the present invention, the amount of charge can be increased.
As a sixth configuration of the present invention, the magnet of the rotating body is symmetric with respect to the coil portion, and is fixed to the rotating shaft so as to face the rotating body, so that the rotating body and the rotating shaft rotate integrally. According to the present invention, since a stable magnetic field can be supplied to the coil portion, power generation efficiency can be increased.
As a seventh configuration of the present invention, the yoke body includes a yoke face plate having a fan part having an angle of 180 ° or less formed by two radii of the fan and a main part of the fan part, and along the outer peripheral edge of the fan part. A magnet positioning plate provided so as to be perpendicular to the surface of the fan part, and a mounting hole for a rotation shaft in a main part of the fan part, the yoke body being surrounded by the yoke face plate and the magnet positioning plate A fan-shaped magnet installation part is formed, the magnet is formed into a fan shape corresponding to the magnet installation part, a curved notch part corresponding to the outer peripheral surface of the rotating shaft is formed at the center of the magnet fan, and the magnet installation part is installed. I tried to do it. According to the present invention, since the magnet is not provided with the attachment portion to the rotating shaft, the rotating body can be more easily rotated. Therefore, the speed at which the direction of the magnetic flux φ passing through the space in the cylinder of the coil winding body is changed. It becomes faster, high power can be obtained, efficient continuous power generation becomes possible, and the amount of power generation can be increased. Further, since the magnet is used as the eccentric weight, the number of parts can be reduced. In addition, the magnet can easily rotate and high power can be obtained, so that the amount of power generation can be increased.
As an eighth configuration of the present invention, the attachment hole is formed as a hole having a straight line with at least one side, and the cross-sectional shape of the portion of the rotating shaft to which the attachment hole is attached is formed in a shape corresponding to the hole. I made it. According to the present invention, the magnet of the rotating body is positioned so that the rotating body and the rotating shaft can rotate together while the magnet of the rotating body is maintained in a symmetric shape with the coil portion as the center. The work of attaching to the rotating shaft becomes easy.
As a ninth configuration of the present invention, the coil portion is fixed to a coil portion fixing member fixed to the inner surface of the tire via a base. According to the present invention, it is possible to accurately maintain the position of the coil portion with respect to the magnets of the rotating bodies that rotate opposite to each other, prevent disturbance of the magnetic flux φ, and increase the power generation efficiency.
As a tenth configuration of the present invention, the rotating shaft is attached to the back surface of the tread surface so as to extend in the width direction of the tire. According to the present invention, the rotating body easily rotates according to the change in the centrifugal force applied to the tire when the vehicle travels, and high power can be obtained, so that the amount of power generation can be increased.

本発明に係るタイヤ内発電装置を示す斜視図。The perspective view which shows the electric power generating apparatus in a tire which concerns on this invention. 本発明に係るタイヤ内発電装置を示す分解斜視図。The disassembled perspective view which shows the in-tire electric power generating apparatus which concerns on this invention. 本発明に係るタイヤ内発電装置を示す断面図。Sectional drawing which shows the in-tire electric power generating apparatus which concerns on this invention. 本発明に係るコイル部と接続される電気部品群を示すブロック図。The block diagram which shows the electrical component group connected with the coil part which concerns on this invention. 本発明に係る回転体におけるヨーク体の形状を示す図。The figure which shows the shape of the yoke body in the rotary body which concerns on this invention. 本発明に係るヨーク体の形状を示す断面図。Sectional drawing which shows the shape of the yoke body which concerns on this invention. 本発明に係るヨーク体の形状を示す断面図。Sectional drawing which shows the shape of the yoke body which concerns on this invention. 本発明に係るコイル部と磁石との関係を示す斜視図。The perspective view which shows the relationship between the coil part which concerns on this invention, and a magnet. 本発明に係るヨーク面板の効果を検証するためのヨーク面板及び磁石のモデル図。FIG. 3 is a model diagram of a yoke face plate and a magnet for verifying the effect of the yoke face plate according to the present invention. 本発明に係るヨーク面板の形状の違いによる効果を検証するモデル図及び形状寸法表。The model figure and shape dimension table | surface which verify the effect by the difference in the shape of the yoke face plate which concerns on this invention. 本発明に係るヨーク面板の端部の厚さと磁力との関係を示すグラフ。The graph which shows the relationship between the thickness of the edge part of the yoke faceplate which concerns on this invention, and magnetic force.

以下、発明の実施形態を通じて本発明を詳説するが、以下の実施形態は特許請求の範囲に係る発明を限定するものではなく、また実施形態の中で説明される特徴の組合せのすべてが発明の解決手段に必須であるとは限らず、選択的に採用される構成を含むものである。 Hereinafter, the present invention will be described in detail through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims, and all combinations of features described in the embodiments are included in the invention. It is not necessarily essential to the solution, but includes a configuration that is selectively adopted.

実施形態
図１，図２に示すように、タイヤ気室内に取付けられるタイヤ内発電装置１は、ベース２と、２つの回転軸支持部材３；３と、１本の真っ直ぐな回転軸４と、コイル部固定部材５と、コイル部６と、２つの回転体７；７とを備える。コイル部６の両端は電線２３により整流回路１８（図４参照）に接続される。ベース２、２つの回転軸支持部材３；３、回転軸４、コイル部固定部材５は、非磁性材料により形成される。ベース２、回転軸支持部材３；３、コイル部固定部材５は、例えば、アクリル樹脂により形成され、回転軸４は、例えば、ＪＩＳ規格のＳＵＳ３０４により形成される。なお、本実施形態において説明に用いる、上下，前後，左右の位置関係は、図１において矢印で示した。 Embodiment As shown in FIG. 1 and FIG. 2, the in-tire power generator 1 mounted in a tire chamber includes a base 2, two rotating shaft support members 3; 3, and a single rotating shaft 4. The coil part fixing member 5, the coil part 6, and the two rotary bodies 7; 7 are provided. Both ends of the coil portion 6 are connected to a rectifier circuit 18 (see FIG. 4) by electric wires 23. The base 2, the two rotating shaft support members 3; 3, the rotating shaft 4, and the coil portion fixing member 5 are formed of a nonmagnetic material. The base 2, the rotation shaft support member 3; 3, and the coil portion fixing member 5 are formed of, for example, acrylic resin, and the rotation shaft 4 is formed of, for example, JIS 304 SUS304. In addition, the positional relationship of up and down, front and rear, and left and right used for explanation in the present embodiment is indicated by arrows in FIG.

ベース２は、例えば、矩形の平板により形成されたベース板１１と、ベース板１１上に設けられた固定台１２とを備える。固定台１２は、下板１３と、左右一対の側壁１４；１４と、屋根板１５と、左右の側設置台１６；１６と、収納設置空間１７とを備える。下板１３は、ベース板１１より一回り小さい矩形の平板状であってベース板１１上にベース板１１と同心に設けられる。左右一対の側壁１４；１４は、下板１３上に間隔を隔てて設けられ、上下方向及び前後方向に延長する。側壁１４；１４は、下板１３上に左右の側縁からそれぞれ等間隔の位置に設けられる。屋根板１５は、左右一対の側壁１４；１４の上端面を跨ぐように設けられる。左右の側設置台１６；１６は、下板１３上の左右の側縁に近い左右の側壁１４；１４の外面と下板１３の上面とから延長するように設けられる。収納設置空間１７は、下板１３と左右の側壁１４；１４と屋根板１５とで囲まれて前後が開口した空間により形成される。収納設置空間１７内には、図４の点線内に示す整流回路１８、充電回路１９、無線モジュールのようなデバイス２０などの電気部品群２２が収納設置される。なお、ベース２は、上述した各部材を組み立てて形成したものでも、一体成型して形成したものでもよい。 The base 2 includes, for example, a base plate 11 formed of a rectangular flat plate and a fixed base 12 provided on the base plate 11. The fixed table 12 includes a lower plate 13, a pair of left and right side walls 14; 14, a roof plate 15, left and right side installation tables 16; 16, and a storage installation space 17. The lower plate 13 is a rectangular flat plate that is slightly smaller than the base plate 11 and is provided on the base plate 11 concentrically with the base plate 11. The pair of left and right side walls 14; 14 are provided on the lower plate 13 with a space therebetween, and extend in the vertical direction and the front-rear direction. The side walls 14; 14 are provided on the lower plate 13 at equal intervals from the left and right side edges, respectively. The roof plate 15 is provided so as to straddle the upper end surfaces of the pair of left and right side walls 14; The left and right side installation bases 16; 16 are provided so as to extend from the outer surfaces of the left and right side walls 14; 14 near the left and right side edges on the lower plate 13 and the upper surface of the lower plate 13. The storage installation space 17 is formed by a space that is surrounded by the lower plate 13, the left and right side walls 14; In the storage / installation space 17, an electrical component group 22 such as a rectifier circuit 18, a charging circuit 19, and a device 20 such as a wireless module shown within a dotted line in FIG. 4 is stored and installed. The base 2 may be formed by assembling the above-described members, or may be formed by integral molding.

屋根板１５の上面、及び、側設置台１６の上面は、ベース板１１の上平面と平行な平面に形成される。回転軸支持部材３は、側設置台１６の上面より上方に延長するように側設置台１６の上面に設けられ、コイル部固定部材５が屋根板１５の上面より上方に延長するように屋根板１５の上面に設けられる。 The upper surface of the roof plate 15 and the upper surface of the side installation table 16 are formed in a plane parallel to the upper plane of the base plate 11. The rotating shaft support member 3 is provided on the upper surface of the side installation table 16 so as to extend upward from the upper surface of the side installation table 16, and the roof plate so that the coil portion fixing member 5 extends upward from the upper surface of the roof plate 15. 15 is provided on the upper surface.

コイル部固定部材５は、屋根板１５と一体に形成されたものでもよいし、屋根板１５と別個に形成されたものが接着剤などの固定手段で屋根板１５の上面に固定されて形成されたものでもよい。コイル部固定部材５は、屋根板１５の左右間の中央位置より上方向及び前後方向に延長して互いに対向する対向面５ａ；５ａを有した平板により形成される。コイル部固定部材５の平板の対向面５ａ；５ａは屋根板１５の上面である平面に対して垂直な面である。コイル部固定部材５は、対向面５ａ；５ａを貫通するコイル部収納貫通孔５ｂと、上縁面を円弧状に切り欠いて形成された軸避け部５ｃとを備える。コイル部６はコイル部収納貫通孔５ｂの孔内壁に接着剤などの固定手段で固定される。 The coil portion fixing member 5 may be formed integrally with the roof plate 15 or may be formed separately from the roof plate 15 and fixed to the upper surface of the roof plate 15 by a fixing means such as an adhesive. May be good. The coil portion fixing member 5 is formed of a flat plate having opposing surfaces 5a; 5a that extend in the upward and front-rear directions from the center position between the left and right sides of the roof plate 15 and face each other. The flat facing surfaces 5 a and 5 a of the coil portion fixing member 5 are surfaces perpendicular to the plane which is the upper surface of the roof plate 15. The coil part fixing member 5 includes a coil part accommodation through hole 5b that penetrates the opposing surface 5a; 5a, and a shaft avoiding part 5c formed by cutting out the upper edge surface in an arc shape. The coil part 6 is fixed to the hole inner wall of the coil part accommodation through hole 5b by a fixing means such as an adhesive.

回転軸支持部材３は、側設置台１６と別個に形成されるものであり、例えば、平板状の壁体により形成され、接着剤などの固定手段で側設置台１６の上面に固定される。回転軸支持部材３は、上部側面に回転軸４の端部４１を回転可能に支持する軸受２１を備える。軸受２１は、回転軸支持部材３の上部側面に形成された孔に取付けられた軸受部材、あるいは、回転軸支持部材３の上部側面に形成された軸受孔により形成される。 The rotating shaft support member 3 is formed separately from the side installation table 16, and is formed of, for example, a flat wall and is fixed to the upper surface of the side installation table 16 by a fixing means such as an adhesive. The rotating shaft support member 3 includes a bearing 21 that rotatably supports the end portion 41 of the rotating shaft 4 on the upper side surface. The bearing 21 is formed by a bearing member attached to a hole formed on the upper side surface of the rotating shaft support member 3 or a bearing hole formed on the upper side surface of the rotating shaft support member 3.

回転軸４は、両端部４１；４１と、ヨーク体位置決め部４２、磁石対応部４３、軸補強部４４とを備える。回転軸４の両端部４１；４１が各回転軸支持部材３；３の軸受２１；２１に回転可能に支持される。図２に示すように、回転軸４は、中央部に軸補強部４４を備え、軸補強部４４と端部４１との間には、ヨーク体位置決め部４２と磁石対応部４３とを備える。軸補強部４４と磁石対応部４３と端部４１とが断面円形状に形成され、ヨーク体位置決め部４２が断面角形状に形成される。ヨーク体位置決め部４２は、例えば断面正六角形状に形成される。軸補強部４４と左右の磁石対応部４３；４３とが隣り合うように設けられ、磁石対応部４３とヨーク体位置決め部４２とが隣り合うように設けられ、ヨーク体位置決め部４２と端部４１とが隣り合うように設けられる。 The rotating shaft 4 includes both end portions 41; 41, a yoke body positioning portion 42, a magnet corresponding portion 43, and a shaft reinforcing portion 44. Both end portions 41; 41 of the rotary shaft 4 are rotatably supported by bearings 21; 21 of the rotary shaft support members 3; As shown in FIG. 2, the rotating shaft 4 includes a shaft reinforcing portion 44 at the center, and includes a yoke body positioning portion 42 and a magnet corresponding portion 43 between the shaft reinforcing portion 44 and the end portion 41. The shaft reinforcing portion 44, the magnet corresponding portion 43, and the end portion 41 are formed in a circular cross section, and the yoke body positioning portion 42 is formed in a square cross section. The yoke body positioning portion 42 is formed, for example, in a regular hexagonal cross section. The shaft reinforcing portion 44 and the left and right magnet corresponding portions 43; 43 are provided adjacent to each other, the magnet corresponding portion 43 and the yoke body positioning portion 42 are provided adjacent to each other, and the yoke body positioning portion 42 and the end portion 41 are provided. Are provided next to each other.

回転軸４の端部４１の断面円径寸法は、ヨーク体位置決め部４２の断面正六角形の内接円の円径寸法以下に形成される。磁石対応部４３の断面円径寸法は、ヨーク体位置決め部４２の断面正六角形の外接円の円径寸法以上に形成される。軸補強部４４の断面円径寸法は、磁石対応部４３の円径寸法よりも大きい寸法に形成される。 The cross-sectional diameter of the end 41 of the rotating shaft 4 is formed to be equal to or smaller than the diameter of the inscribed circle having a regular hexagonal cross section of the yoke body positioning portion 42. The cross-sectional diameter of the magnet corresponding portion 43 is formed to be equal to or larger than the diameter of the circumscribed circle having a regular hexagonal cross section of the yoke body positioning portion 42. The cross-sectional diameter of the shaft reinforcing portion 44 is formed to be larger than the diameter of the magnet corresponding portion 43.

回転体７は、扇形状のヨーク体７１と磁石７２とにより構成し、ヨーク体７１と磁石７２とを組み合わせることで扇形状の偏心錘を形成する。
ヨーク体７１は、扇形状のヨーク面板７３と、位置決め孔７４と、磁石位置決め板７５；７５；７６とを備える。ヨーク面板７３は、扇部７３ａと扇の要部７３ｂとを備える。ヨーク面板７３の扇形状は、扇の２つの半径線のなす角度が例えば１２０°に形成される。位置決め孔７４は、ヨーク面板７３の扇の要部７３ｂに形成された孔であり、回転軸４のヨーク体位置決め部４２の断面正六角形状に対応した正六角形状の孔に形成される。磁石位置決め板７５；７５は、ヨーク面板７３の２つの半径線縁Ｃ１に沿って設けられる。磁石位置決め板７６は、ヨーク面板７３の円弧線縁Ｃ２に沿って設けられる。磁石位置決め板７５；７５；７６は、ヨーク面板７３の一方の面より一方向に突出し、かつ、ヨーク面板７３と垂直に形成される。
また、ヨーク面板７３の扇部７３ａは、扇部７３ａを半分に分割する半径方向中心線Ｐの中心部分の厚さＨ（図５参照）が扇部７３ａの内側半径及び外側半径の厚さよりも厚く、かつ、半径線縁Ｃ１；Ｃ１の厚さよりも厚くなるように山型に形成される。具体的には、扇部７３ａの２つの半径線縁Ｃ１；Ｃ１の円弧側の端部同士を結ぶ線分Ｑ（図５参照）と、２つの半径線の挟角を２分する半径方向中心線Ｐとの交点部分の厚さＨ（図５参照）が最も厚くなるように形成される。つまり、扇部７３ａは、錐体状に形成される。
よって、扇部７３ａは、図５に示す半径方向中心線Ｐに直交する断面Ｓ１−Ｓ１；Ｓ２−Ｓ２；Ｓ３−Ｓ３；Ｓ４−Ｓ４において、図６（ａ）〜（ｄ）に示すように、断面が三角形状となるように形成される。また、扇部７３ａは、図５に示す扇部７３ａの２つの半径線縁Ｃ１；Ｃ１の円弧側の端部同士を結ぶ線分Ｑに直交する断面Ｔ１−Ｔ１：Ｔ２−Ｔ２；Ｔ３−Ｔ３において、図７（ａ）〜（ｃ）に示すように、断面が三角形状となるように形成される。上記扇部７３ａの形状の設定の方法については後段において詳述する。なお、半径方向中心線Ｐは、後述の磁石７２を構成する単位扇形状磁石７７,７７の接着位置である極性の反転する位置に対応する。 The rotating body 7 is constituted by a fan-shaped yoke body 71 and a magnet 72, and a fan-shaped eccentric weight is formed by combining the yoke body 71 and the magnet 72.
The yoke body 71 includes a fan-shaped yoke face plate 73, a positioning hole 74, and magnet positioning plates 75; The yoke face plate 73 includes a fan part 73a and a main part 73b of the fan. The fan face of the yoke face plate 73 is formed such that the angle formed by the two radial lines of the fan is 120 °, for example. The positioning hole 74 is a hole formed in the main part 73 b of the fan of the yoke face plate 73, and is formed in a regular hexagonal hole corresponding to the regular hexagonal cross section of the yoke body positioning part 42 of the rotating shaft 4. The magnet positioning plates 75; 75 are provided along the two radial line edges C1 of the yoke face plate 73. The magnet positioning plate 76 is provided along the arcuate line edge C2 of the yoke face plate 73. The magnet positioning plates 75; 75; 76 protrude in one direction from one surface of the yoke face plate 73 and are formed perpendicular to the yoke face plate 73.
Further, in the fan portion 73a of the yoke face plate 73, the thickness H (see FIG. 5) of the central portion of the radial center line P that divides the fan portion 73a in half is larger than the thickness of the inner radius and the outer radius of the fan portion 73a. It is formed in a mountain shape so as to be thicker and thicker than the thickness of the radial line edge C1; C1. Specifically, the radial center that bisects the angle Q between the two radial line edges C1 of the fan part 73a; the end of the arc side of C1 (see FIG. 5) and the angle between the two radial lines. It is formed so that the thickness H (see FIG. 5) of the intersection with the line P is the thickest. That is, the fan part 73a is formed in a cone shape.
Therefore, the fan portion 73a has cross sections S1-S1; S2-S2; S3-S3; S4-S4 perpendicular to the radial center line P shown in FIG. 5 as shown in FIGS. The cross section is formed in a triangular shape. Further, the fan portion 73a has a cross section T1-T1: T2-T2; T3-T3 orthogonal to a line segment Q connecting the two radial line edges C1 of the fan portion 73a shown in FIG. 7A to 7C, the cross section is formed in a triangular shape. The method for setting the shape of the fan 73a will be described in detail later. The radial center line P corresponds to a position where the polarity is reversed, which is an adhesion position of unit fan-shaped magnets 77 and 77 constituting a magnet 72 described later.

磁石７２は、円の中心に円孔を備えた所定厚さの円板を円の中心を要とした扇形状に分割した扇形状の磁石により形成される。磁石７２の扇の要には回転軸４の外周面に対応する湾曲切欠部８０を備える。例えば、２つの半径のなす角度が例えば６０°の単位扇形状磁石７７を２つを組み合わせて２つの半径のなす角度が１２０°の扇形状に形成された扇形状の磁石７２を用いる。このような２つの半径のなす角度が６０°の単位扇形状磁石７７を用いることにより、安定的な磁力が得られ、また、コイル巻体６１の筒内の空間６０（図８参照）を通過する磁束φの向きが変化する速度を速くできるため、効率的に発電できる。
なお、単位扇形状磁石７７を６０°に設定したが、単位扇形状磁石７７を３０°に設定して、周方向に異なる磁極が交互に配置されるように磁石７２を構成しても良く、適宜コイル巻体６１の形状に応じて設定すれば良い。 The magnet 72 is formed of a fan-shaped magnet obtained by dividing a circular plate having a predetermined thickness with a circular hole at the center of the circle into a fan shape that requires the center of the circle. The main part of the fan of the magnet 72 includes a curved notch 80 corresponding to the outer peripheral surface of the rotating shaft 4. For example, a fan-shaped magnet 72 formed by combining two unit fan-shaped magnets 77 having an angle between two radii of, for example, 60 ° and formed into a fan shape having an angle formed by two radii of 120 ° is used. By using such a unit fan-shaped magnet 77 having an angle of 60 ° between the two radii, a stable magnetic force can be obtained, and the coil 60 passes through the space 60 (see FIG. 8) in the cylinder. Since the speed at which the direction of the magnetic flux φ to be changed can be increased, power can be generated efficiently.
Although the unit fan-shaped magnet 77 is set to 60 °, the unit 72-shaped magnet 77 may be set to 30 °, and the magnet 72 may be configured so that different magnetic poles are alternately arranged in the circumferential direction. What is necessary is just to set suitably according to the shape of the coil winding body 61. FIG.

以下、ヨーク体７１の扇部７３ａの形状の設定について、図５（ｃ）を参照して説明する。
ヨーク体７１の扇部７３ａは、磁石７２から放出される磁束φにより、ヨーク体７１が飽和磁場となるように形状が設定される。ヨーク体７１の磁場の最大飽和密度Ｂｍは、ヨーク体７１を構成する素材の固有のものであり、素材により異なる。例えば、２極の磁石においてＮ極からＳ極に放出される磁束φは、磁石端から極性の反転する変化点に向かって比例して増加する。よって、回転方向に隣接する一方の単位扇形状磁石７７から放出される磁束密度Ｂｍａｇが、すべて他方の単位扇形状磁石７７に吸引されるようにすれば良いので、放出される磁束密度Ｂｍａｇが扇部７３ａの厚さ断面において最大飽和密度Ｂｍで飽和するように扇部７３ａの厚さＨを設定すれば良い。つまり、磁石の放出する磁束密度Ｂｍａｇとヨーク体７１の磁場の最大飽和密度Ｂｍとの関係ｔａｎθ＝Ｂｍａｇ/Ｂｍから扇部７３ａの厚さＨを設定することができる。
例えば、本実施形態では、回転体７の磁石をネオジウム磁石、ヨーク体７１をパーメンジュール（軟鉄）により構成し、次のようにヨーク体７１の形状を設定する。
ネオジウム磁石の磁束密度Ｂｍａｇは１．４Ｔ、パーメンジュールの最大飽和密度Ｂｍは２．４Ｔの物性を有する。よって、単位扇形状磁石７７から垂直に放出される磁束密度Ｂｍａｇよりもヨーク体７１の最大飽和密度Ｂｍが等しいか、大きくなるように厚さＨを決定すれば良い。つまり、単位扇形状磁石７７から放出される磁束φは、ヨーク体７１に沿って曲がるため、単位扇形状磁石７７により放出される単位面積あたりの磁束密度Ｂｍａｇよりもヨーク体７１の単位断面あたりの最大飽和密度Ｂｍが等しいか大きければ良い。磁束密度Ｂｍａｇとヨーク体７１の最大飽和密度Ｂｍの奥行き方向の長さを同じとすれば、単位長さあたりの磁束密度Ｂｍａｇに対して、ヨーク体７１の厚さＨは１．４Ｔ/２．４Ｔ＝約０．５８３３倍（ｔａｎθ＝約３０度）の厚さＨがあれば良いことになる。よって、半径方向中心線Ｐの位置でのヨーク体７１の厚さＨは、ヨーク体７１の（断面長さＬ/２）×（Ｂｍａｇ/Ｂｍ）を計算することにより設定される。
なお、ヨーク体７１は、鉄、ニッケル、パーマロイ、センダスト、アモルファス金属などの軟磁性体により形成しても良い。 Hereinafter, the setting of the shape of the fan part 73a of the yoke body 71 will be described with reference to FIG.
The shape of the fan portion 73 a of the yoke body 71 is set so that the yoke body 71 becomes a saturated magnetic field by the magnetic flux φ emitted from the magnet 72. The maximum saturation density Bm of the magnetic field of the yoke body 71 is unique to the material constituting the yoke body 71 and varies depending on the material. For example, the magnetic flux φ emitted from the N pole to the S pole in a two-pole magnet increases in proportion from the magnet end toward the changing point where the polarity is reversed. Therefore, the magnetic flux density Bmag emitted from one unit fan-shaped magnet 77 adjacent in the rotation direction may be all attracted to the other unit fan-shaped magnet 77, so that the released magnetic flux density Bmag is a fan. What is necessary is just to set the thickness H of the fan part 73a so that it may be saturated with the maximum saturation density Bm in the thickness cross section of the part 73a. That is, the thickness H of the fan 73a can be set from the relationship tan θ = Bmag / Bm between the magnetic flux density Bmag emitted from the magnet and the maximum saturation density Bm of the magnetic field of the yoke body 71.
For example, in this embodiment, the magnet of the rotating body 7 is composed of a neodymium magnet, the yoke body 71 is composed of permendur (soft iron), and the shape of the yoke body 71 is set as follows.
A neodymium magnet has a magnetic flux density Bmag of 1.4T, and a permendurous maximum saturation density Bm of 2.4T. Therefore, the thickness H may be determined so that the maximum saturation density Bm of the yoke body 71 is equal to or greater than the magnetic flux density Bmag emitted perpendicularly from the unit fan-shaped magnet 77. That is, since the magnetic flux φ emitted from the unit fan-shaped magnet 77 bends along the yoke body 71, the magnetic flux per unit section of the yoke body 71 is larger than the magnetic flux density Bmag per unit area emitted by the unit fan-shaped magnet 77. It is sufficient if the maximum saturation density Bm is equal or larger. If the magnetic flux density Bmag and the length in the depth direction of the maximum saturation density Bm of the yoke body 71 are the same, the thickness H of the yoke body 71 is 1.4T / 2. With respect to the magnetic flux density Bmag per unit length. A thickness H of 4T = about 0.5833 times (tan θ = about 30 degrees) is sufficient. Therefore, the thickness H of the yoke body 71 at the position of the radial center line P is set by calculating (cross-sectional length L / 2) × (Bmag / Bm) of the yoke body 71.
The yoke body 71 may be formed of a soft magnetic material such as iron, nickel, permalloy, sendust, or amorphous metal.

図８に示すように、単位扇形状磁石７７は、一方の扇面側がＮ極に着磁され、他方の扇面側がＳ極に着磁されて形成された磁石である。扇形状磁石７２は、異極同士が互いに隣り合うように２つの単位扇形状磁石７７；７７の端面７８；７８同士が接着されて形成される。
即ち、回転体７が、回転体７の回転方向に沿って配置された複数の異なる磁極の単位扇形状磁石７７；７７を備えるので、磁極の変化点が多くなり、回転体７が回転することによりコイル巻体６１の筒内の空間６０を通過する磁束φの向きを変化させる速度が速くなるので、高電力を得ることができるようになる。 As shown in FIG. 8, the unit fan-shaped magnet 77 is a magnet formed by magnetizing one fan face side to the N pole and magnetizing the other fan face side to the S pole. The fan-shaped magnet 72 is formed by adhering the end faces 78; 78 of the two unit fan-shaped magnets 77; 77 so that the different poles are adjacent to each other.
That is, the rotating body 7 includes a plurality of unit fan-shaped magnets 77 and 77 of different magnetic poles arranged along the rotating direction of the rotating body 7, so that the number of magnetic pole change points increases and the rotating body 7 rotates. As a result, the speed of changing the direction of the magnetic flux φ passing through the space 60 in the cylinder of the coil winding body 61 is increased, so that high power can be obtained.

磁石７２は、磁石位置決め板７５；７５；７６で囲まれた磁石設置部７９内に挿入可能な大きさに形成される。
例えば、磁石位置決め板７５；７５；７６で囲まれた扇部７３ａの一方の扇面７３ｕの面積と同じ面積の扇面を有した扇形状の磁石７２を形成し、扇部７３ａの一方の扇面７３ｕと磁石７２の一方の扇面とが互いに接着剤などの固定手段で固定されて回転体７が形成される。
即ち、回転体７の磁石７２は、コイル部６に対向する面とは反対側の面にヨーク面板７３を備え、かつ、磁石７２の扇の外周面にヨークとして機能する磁石位置決め板７５；７５；７６を備える構成としたので、磁石７２内で自己完結する磁界発生状態を抑制できてコイル巻体６１の筒内の空間６０を通過する磁束φの磁束密度を大きくできるので、高電力を得ることができるようになる。
ヨーク体７１が磁石設置部７９を備えるので、磁石７２をヨーク体７１の決まった位置である磁石設置部７９に容易に設置できるとともに、回転体７の製作が容易となる。また、磁石７２の位置ずれも防止できるので、コイル部６に安定的な磁界を供給できる。
さらに、回転体７の回転方向に沿って磁極が交互に入れ替わるように磁石設置部７９に配置した複数の磁石７２の磁極が反転する位置に対応して、ヨーク体７１の厚さＨを磁石位置決め板７５；７５；７６が形成される位置の厚さよりも厚くすることで、単位扇形状磁石７７から放出される全ての磁束φをヨーク体７１内に通過させることができ、互いに対向する単位扇形状磁石７７：７７の互いに異なる磁極間で発生する磁束φを最大に設定することができる。 The magnet 72 is formed in a size that can be inserted into a magnet installation portion 79 surrounded by magnet positioning plates 75;
For example, a fan-shaped magnet 72 having a fan surface having the same area as the one fan surface 73u of the fan portion 73a surrounded by the magnet positioning plates 75; 75; 76 is formed, and the one fan surface 73u of the fan portion 73a The rotating body 7 is formed by fixing one fan surface of the magnet 72 to each other by a fixing means such as an adhesive.
That is, the magnet 72 of the rotating body 7 includes the yoke face plate 73 on the surface opposite to the face facing the coil portion 6, and the magnet positioning plate 75; 75 that functions as a yoke on the outer peripheral surface of the fan of the magnet 72. , Since the magnetic field generation state that is self-contained in the magnet 72 can be suppressed and the magnetic flux density of the magnetic flux φ passing through the space 60 in the cylinder of the coil winding body 61 can be increased, high power is obtained. Will be able to.
Since the yoke body 71 includes the magnet installation part 79, the magnet 72 can be easily installed on the magnet installation part 79, which is a fixed position of the yoke body 71, and the rotating body 7 can be easily manufactured. In addition, since the displacement of the magnet 72 can be prevented, a stable magnetic field can be supplied to the coil unit 6.
Further, the thickness H of the yoke body 71 is magnet-positioned corresponding to the position where the magnetic poles of the plurality of magnets 72 arranged in the magnet installation part 79 are reversed so that the magnetic poles are alternately switched along the rotation direction of the rotating body 7. By making it thicker than the position where the plates 75; 75; 76 are formed, all the magnetic flux φ emitted from the unit fan-shaped magnet 77 can be passed through the yoke body 71, and the unit fans facing each other. The magnetic flux φ generated between the different magnetic poles of the shaped magnet 77: 77 can be set to the maximum.

また、回転体７は、ヨーク体７１の扇部の要部７３ｂが回転軸４への取付孔としての位置決め孔７４を備え、磁石７２がヨーク面板７３と磁石位置決め板７５；７５；７６とで囲まれた扇形状の磁石設置部７９に対応する扇形状に形成され、磁石７２の扇の要には回転軸４の外周面に対応する湾曲切欠部８０を備え、磁石設置部７９に設置される構成とした。
即ち、磁石７２に回転軸４への取付部を設けない構成としたので、回転体７がより回転しやすくなるので、コイル巻体６１の筒内の空間６０を通過する磁束φの向きが変化する速度がより速くなって、高電力を得ることができ、また、効率的な連続発電が可能となり、発電量を増加させることができる。
また、磁石７２を偏心錘として利用したので、部品点数を削減できるとともに、磁石７２が回転しやすくなり、高電力を得ることができるので、発電量を増加させることができるようになる。 Further, in the rotating body 7, the main part 73 b of the fan part of the yoke body 71 includes a positioning hole 74 as an attachment hole to the rotating shaft 4, and the magnet 72 includes a yoke face plate 73 and magnet positioning plates 75; It is formed in a fan shape corresponding to the enclosed fan-shaped magnet installation part 79, and the main part of the fan of the magnet 72 is provided with a curved notch 80 corresponding to the outer peripheral surface of the rotating shaft 4, and is installed in the magnet installation part 79. The configuration is as follows.
That is, since the magnet 72 is not provided with the attachment portion to the rotating shaft 4, the rotating body 7 becomes easier to rotate, and the direction of the magnetic flux φ passing through the space 60 in the cylinder of the coil winding body 61 changes. The speed at which the power generation is performed becomes higher, high power can be obtained, efficient continuous power generation becomes possible, and the amount of power generation can be increased.
Further, since the magnet 72 is used as an eccentric weight, the number of parts can be reduced, and the magnet 72 can be easily rotated and high power can be obtained, so that the amount of power generation can be increased.

また、回転体７の磁石７２が回転軸４の軸補強部４４側に位置されるように、ヨーク体７１の位置決め孔７４内に回転軸４の端部４１側から断面六角形のヨーク体位置決め部４２を嵌め込んで、図３に示すように、ヨーク面板７３の扇の要部７３ｂにおける位置決め孔７４の孔縁部面４６と回転軸４の磁石対応部４３の端面４５とを接触させる。この際、ヨーク体７１と回転軸４とを接着剤などの固定手段で固定すれば、ヨーク体７１と回転軸４とをより確実に一体化させることができる。
そして、回転軸４の端部４１；４１を回転軸支持部材３の軸受２１内に回転可能に挿入した状態で、回転軸支持部材３を屋根板１５の上面に接着剤などの固定手段で固定する。
回転軸４の各ヨーク体位置決め部４２；４２には、各回転体７；７の磁石７２；７２の扇面同士が向き合うように取付けられる。
本実施形態では、ヨーク体位置決め部４２の断面形状及び位置決め孔７４の孔形状を正六角形状としたので、磁石７２；７２の扇面の中心線が一致し、磁石７２；７２の扇面同士が向き合うように磁石７２；７２を位置決めして回転軸４の各ヨーク体位置決め部４２；４２に回転体７を取付ける取付作業が容易となる。なお、位置決め孔７４の孔形状を、三つ以上の角を備えた角孔とし、ヨーク体位置決め部４２の断面形状は角孔に対応した角形状とすれば、当該取付作業が容易となる。 Further, the yoke body positioning having a hexagonal cross section from the end 41 side of the rotating shaft 4 is positioned in the positioning hole 74 of the yoke body 71 so that the magnet 72 of the rotating body 7 is positioned on the shaft reinforcing portion 44 side of the rotating shaft 4. As shown in FIG. 3, the edge 42 of the positioning hole 74 in the main portion 73 b of the yoke face plate 73 and the end face 45 of the magnet corresponding portion 43 of the rotating shaft 4 are brought into contact with each other. At this time, if the yoke body 71 and the rotating shaft 4 are fixed by a fixing means such as an adhesive, the yoke body 71 and the rotating shaft 4 can be more reliably integrated.
The rotary shaft support member 3 is fixed to the upper surface of the roof plate 15 with a fixing means such as an adhesive in a state where the end portions 41; 41 of the rotary shaft 4 are rotatably inserted into the bearing 21 of the rotary shaft support member 3. To do.
The yoke body positioning portions 42; 42 of the rotary shaft 4 are attached so that the fan surfaces of the magnets 72; 72 of the rotary bodies 7; 7 face each other.
In the present embodiment, since the cross-sectional shape of the yoke body positioning portion 42 and the hole shape of the positioning hole 74 are regular hexagonal shapes, the center lines of the fan surfaces of the magnets 72; 72 coincide with each other and the fan surfaces of the magnets 72; 72 face each other. Thus, the magnet 72; 72 is positioned so that the attaching work for attaching the rotating body 7 to each yoke body positioning portion 42; 42 of the rotating shaft 4 is facilitated. In addition, if the hole shape of the positioning hole 74 is a square hole having three or more corners, and the cross-sectional shape of the yoke body positioning portion 42 is a square shape corresponding to the square hole, the mounting operation is facilitated.

軸受２１に回転可能に支持された回転軸４と、回転軸４の中心線を回転中心として回転軸４と一緒に回転するように形成された回転体７とにより、回転構成部２５（図１参照）が形成される。回転体７は、回転中心と重心とが異なるものであればよく、例えば、扇の２つの半径のなす角度が例えば１８０°以下の扇形状により形成されたものを用いればよい。 A rotating component 25 (FIG. 1) includes a rotating shaft 4 rotatably supported by a bearing 21 and a rotating body 7 formed so as to rotate together with the rotating shaft 4 about the center line of the rotating shaft 4 as a rotation center. Reference) is formed. The rotating body 7 only needs to have a rotation center and a center of gravity different from each other. For example, a rotating body formed in a fan shape in which an angle between two radii of a fan is 180 ° or less may be used.

また、図８に示すように、コイル部６は、回転軸４と一緒に回転して互いに向き合う２つの回転体７；７における磁石７２；７２の互いに異なる磁極間で発生する磁束φが通る空間６０を取り囲む筒形状にコイル６２が巻回された２つのコイル巻体６１；６１により形成される。例えば、コイル巻体６１は、回転する２つの回転体７；７の磁石７２；７２間で発生する磁束φが通る扇形の筒を形成するようにコイル６２が巻かれた構成である。好ましくは、コイル６２として、断面矩形状の平角線を用いる。これにより、巻線抵抗減少と巻数増加が図れ、巻線密度を向上できるので、発電効率を高めることができる。 As shown in FIG. 8, the coil section 6 is a space through which the magnetic flux φ generated between the different magnetic poles of the magnets 72; 72 in the two rotating bodies 7; 7 that rotate together with the rotating shaft 4 and face each other. It is formed by two coil winding bodies 61; 61 in which a coil 62 is wound in a cylindrical shape surrounding 60. For example, the coil wound body 61 has a configuration in which the coil 62 is wound so as to form a fan-shaped cylinder through which the magnetic flux φ generated between the two rotating bodies 7; Preferably, a rectangular wire having a rectangular cross section is used as the coil 62. Thereby, the winding resistance can be reduced and the number of turns can be increased, and the winding density can be improved, so that the power generation efficiency can be increased.

図１；図８に示すように、コイル巻体６１は、回転体７の磁石７２の回転軌跡の投影部分に設けられたので、コイル巻体６１の筒内の空間６０を通過する磁束φの磁束密度を大きくでき、高電力を得ることができる。
例えば、コイル部６の外周を磁石７２の外周より大きくした場合、コイル巻体６１の巻長さが長くなることで、コイル巻体６１の抵抗が大きくなり、発電効率が悪化するが、コイル巻体６１の筒の断面の外周形状と磁石７２の断面の外周形状とを同じ形状に形成し、さらに、回転体７が回転し、磁石７２の断面の中心線とコイル巻体６１の筒の断面の中心線とが一致したときに、コイル巻体６１の筒の断面の外周の長さが磁石７２の断面の外周の長さよりも小さくなるように形成することで、コイル巻体６１の抵抗を小さくしつつ、発電効率を高めることができる。
また、回転体７が回転した場合において、回転軸４に沿った方向で単位扇形状磁石７７の扇面とコイル巻体６１の扇形状の筒の端部とが対向するように構成し、コイル部６を中心として回転体７；７の磁石７２；７２が左右対称に位置するので、コイル部６に対して安定した磁界を供給でき、発電効率を高めることができる。 As shown in FIG. 1; FIG. 8, the coil winding body 61 is provided on the projected portion of the rotation locus of the magnet 72 of the rotating body 7, so that the magnetic flux φ passing through the space 60 in the cylinder of the coil winding body 61. Magnetic flux density can be increased and high power can be obtained.
For example, when the outer periphery of the coil portion 6 is made larger than the outer periphery of the magnet 72, the coil winding body 61 has a longer winding length, which increases the resistance of the coil winding body 61 and decreases the power generation efficiency. The outer peripheral shape of the cross section of the cylinder of the body 61 and the outer peripheral shape of the cross section of the magnet 72 are formed in the same shape, and the rotating body 7 is further rotated. Is formed so that the length of the outer circumference of the cross section of the cylinder of the coil winding body 61 is smaller than the length of the outer circumference of the cross section of the magnet 72. The power generation efficiency can be increased while reducing the size.
Further, when the rotating body 7 rotates, the fan face of the unit fan-shaped magnet 77 and the end of the fan-shaped cylinder of the coil winding body 61 are configured to face each other in the direction along the rotation axis 4. Since the magnets 72; 72 of the rotating body 7; 7 are positioned symmetrically with respect to 6 as a center, a stable magnetic field can be supplied to the coil portion 6 and the power generation efficiency can be increased.

図３に示すように、回転軸支持部材３；３間の間隔ｃは、回転軸４の全長よりも短く、かつ、回転軸４の両端部４１；４１を除いた部分の長さｄよりも長く形成される。これにより、回転軸支持部材３とヨーク体位置決め部４２との接触干渉を低減させることができるので、回転軸４の回転がスムーズになって磁石７２が回転しやすくなり、高電力を得ることができるので、発電量を増加させることができる。さらに、回転軸４が軸受２１よりはずれてしまうことを防止できる。
さらに、ヨーク面板７３の扇の要部７３ｂにおける位置決め孔７４の孔縁部面４６と回転軸４の磁石対応部４３の端面４５とが接触するように、ヨーク体位置決め部４２と位置決め孔７４とが嵌め合わされる構成としたので、回転体７の磁石７２とコイル部６との間の距離がほぼ一定に保たれ、効率良く、安定的に電圧を発生できる。 As shown in FIG. 3, the distance c between the rotating shaft support members 3; 3 is shorter than the entire length of the rotating shaft 4 and is longer than the length d of the portion excluding both ends 41; 41 of the rotating shaft 4. Long formed. Thereby, contact interference between the rotating shaft support member 3 and the yoke body positioning portion 42 can be reduced, so that the rotating shaft 4 can be smoothly rotated and the magnet 72 can be easily rotated to obtain high power. As a result, the amount of power generation can be increased. Furthermore, it is possible to prevent the rotating shaft 4 from being detached from the bearing 21.
Further, the yoke body positioning portion 42 and the positioning hole 74 are arranged so that the hole edge surface 46 of the positioning hole 74 and the end surface 45 of the magnet corresponding portion 43 of the rotating shaft 4 in the main portion 73b of the yoke surface plate 73 are in contact with each other. Therefore, the distance between the magnet 72 of the rotating body 7 and the coil portion 6 is kept substantially constant, and a voltage can be generated efficiently and stably.

以上のように構成されたタイヤ内発電装置１は、ベース２の裏面１１ａ（図１参照）が、タイヤ気室内であって例えばトレッド面の裏面に相当する位置に固定される。そして、車を走行させると、タイヤ内振動でもっともエネルギーの高い遠心力の変動により、回転体７；７が回転し、互いに対向する２つの磁石７２；７２も回転する。この２つの磁石７２；７２の回転によって、各コイル巻体６１の筒内の空間６０を通過する磁束φの向きが変化するので、コイル６２に電圧が発生する。この電圧が整流回路１８を通して充電回路１９に充電され、デバイス２０に供給される。 In the in-tire power generator 1 configured as described above, the back surface 11a (see FIG. 1) of the base 2 is fixed at a position corresponding to the back surface of the tread surface, for example, in the tire chamber. When the vehicle is driven, the rotating body 7; 7 rotates due to the fluctuation of the centrifugal force having the highest energy due to the vibration in the tire, and the two magnets 72; 72 facing each other also rotate. The rotation of the two magnets 72; 72 changes the direction of the magnetic flux φ that passes through the space 60 in the cylinder of each coil winding body 61, so that a voltage is generated in the coil 62. This voltage is charged into the charging circuit 19 through the rectifying circuit 18 and supplied to the device 20.

コイル部６の全体に対して１対の整流回路１８と充電回路１９とを設けるようにしても良いが、コイル部６のコイル巻体６１毎に１対の整流回路１８と充電回路１９とを設けるようにすれば、充電量を多くできて好ましい。 A pair of rectifier circuit 18 and charging circuit 19 may be provided for the entire coil unit 6, but a pair of rectifier circuit 18 and charging circuit 19 are provided for each coil winding body 61 of the coil unit 6. If provided, the amount of charge can be increased, which is preferable.

なお、タイヤの回転による振動は、タイヤのベルトの曲げによるヨー変化が引き起こしている。特にタイヤが接地する瞬間、又は、タイヤが接地から離れる瞬間に、タイヤ振動として現れる。この振動は、ベルトからタイヤの中心に近づくほど大きくなる。従って、トレッド面の裏面にベース２を固定し、回転体７を回転可能に支持する回転軸４をトレッド面の裏面よりタイヤの中心側に離れた位置に位置させることにより、回転体７により大きな加速度が働き、回転体７に大きなエネルギーを与えることができるので、トレッド面の裏面よりタイヤの中心方向への距離１０ｍｍ以上４０ｍｍ以下の間に回転軸４を位置させるのがより好ましい。
また、コイル部６をコイル部固定部材５に固定する構成としたので、互いに対向して回転する２つの回転体７；７に対するコイル部６の位置を正確に維持でき、磁束φの乱れを防止できて、発電効率が高くなる。
また、回転軸４を、タイヤの幅方向に延長するようにトレッド面の裏面に取付けることにより、車両走行時のタイヤに加わる遠心力の変化に応じて回転体７が回転しやすくなり、高電力を得ることができるとともに発電量を増加させることができるようになる。 The vibration caused by the rotation of the tire is caused by a yaw change caused by bending of the tire belt. In particular, it appears as tire vibration at the moment when the tire contacts the ground or the moment when the tire leaves the ground. This vibration increases as the distance from the belt approaches the center of the tire. Therefore, the base 2 is fixed to the back surface of the tread surface, and the rotating shaft 4 that rotatably supports the rotating body 7 is positioned at a position away from the back surface of the tread surface toward the center of the tire, thereby making the rotating body 7 larger. Since the acceleration works and can give large energy to the rotating body 7, it is more preferable to position the rotating shaft 4 within a distance of 10 mm or more and 40 mm or less from the back surface of the tread surface toward the center of the tire.
Further, since the coil portion 6 is fixed to the coil portion fixing member 5, the position of the coil portion 6 with respect to the two rotating bodies 7; 7 that rotate opposite to each other can be accurately maintained, and the disturbance of the magnetic flux φ is prevented. And power generation efficiency is increased.
Moreover, by attaching the rotating shaft 4 to the back surface of the tread surface so as to extend in the width direction of the tire, the rotating body 7 can be easily rotated in accordance with a change in centrifugal force applied to the tire during traveling of the vehicle. Can be obtained and the amount of power generation can be increased.

本発明のタイヤ内発電装置１によれば、回転体７の偏心錘を磁石７２により形成したので、回転体７と磁石７２とを別々に備えた構成と比べて、部品点数を削減できるので、小型軽量化が図れる。また、回転体７が回転しやすい構成を備えたので、高電力を得ることができるとともに発電量を増加させることができるようになる。 According to the in-tire power generator 1 of the present invention, since the eccentric weight of the rotating body 7 is formed by the magnet 72, the number of parts can be reduced compared to the configuration in which the rotating body 7 and the magnet 72 are separately provided. Smaller and lighter can be achieved. In addition, since the rotating body 7 is configured to easily rotate, high power can be obtained and the amount of power generation can be increased.

実施例
以下、ヨーク体７１の形状を設定するための実験結果について説明する。
図９は、ヨーク体７１の形状による効果を調べる実験のために用いる回転体７のモデルを示す。図１０（１）,（２）は、実験に用いた回転体７のモデルの異なるパターンのヨーク断面形状を示す図及びその寸法を示す表である。図１１（ａ）〜（ｃ）は、実験により得られたヨーク断面形状と磁力の関係を示すグラフである。なお、ヨーク形状及び寸法は、体積一定の条件の下で設定した。また、ヨーク断面形状とは、中心線Ｐと垂直な面で切断した断面を意味する。
回転体７のモデルは、図９に示すように、磁石７２を１０ｍｍ×１０ｍｍの３ｍｍ厚さの両面４極磁石の磁石により構成し、３ｍｍのエアギャップを隔てて互いに引力が作用するように対向させて磁石を配置する。磁石７２の対向面の裏面側には、体積がそれぞれ２５ｍｍ^３，５０ｍｍ^３，１００ｍｍ^３のパーメンジュール（軟鉄）からなるヨーク面板７３を配置する。図１０（１）に示すように、パターン（ａ）を基準の体積とし、パターン（ａ）の体積が一定となるようにパターン（ｂ）〜（ｆ）のヨーク体７１を用意した。パターン（ａ）〜（ｆ）までの形状の変化は、厚さ一定の平板形状のパターン（ａ）のヨーク面板７３から、端部の厚さ（端部厚みＢ）が０ｍｍかつ中心部の厚さが最大となるパターン（ｆ）まで、端部の厚さを徐々に減少させて得られる計６種類の形状による磁場の変化について調べた。
図１１（ａ）〜（ｃ）に示すように、いずれの体積においても、端部厚みＢが０ｍｍのときに中心点Ｋにおいて最大の磁場が測定されている。なお、中心点Ｋは、磁石７２，７２の対向する面の中心同士を結ぶ線上の中間距離の点である。また、ヨーク断面形状が平板状から台形形状、そして三角形状に近づくに従いエアギャップにおける磁場の強さが強くなっていることが分かる。
さらに、ヨーク体積が１００ｍｍ^３のときに、端部厚みＢが０．２ｍｍのときと端部厚みＢが０ｍｍでは、ほぼ同じ磁場の強さとなっているが、実験に用いた磁石では、ヨーク体積１００ｍｍ^３に設定し、磁極が反転する位置においてヨーク面板７３の厚さＨが最大となるように端部厚みＢを０ｍｍに設定することで磁石７２から放出される磁束φを全てヨーク面板７３を通過させることができ、エアギャップＧ間に配置されるコイル巻体６１に対して最大の磁束φの変化を与えることができる。よって、コイル巻体６１に生じる誘導起電力は最大となり、最も効率の良い発電を可能にできる。
以上より、タイヤ内発電装置１に用いる磁石の磁束密度の強さに対応して、最適な体積を算出するとともに、磁極が反転する位置においてヨーク面板７３の厚さが最大となるようにヨーク面板７３の端部の厚さを０ｍｍに設定することで、単位扇形状磁石７７から隣接する単位扇形状磁石７７に放出される磁束を全てヨーク体７１内に通過させることができる。よって、対向する磁石７２；７２間において最大の磁束φが得られ、当該磁束φ中をコイル巻体６１が通過することにより効率の良い発電が得られる。 Examples Hereinafter, experimental results for setting the shape of the yoke body 71 will be described.
FIG. 9 shows a model of the rotating body 7 used for an experiment for examining the effect of the shape of the yoke body 71. FIGS. 10A and 10B are a diagram showing yoke cross-sectional shapes of different patterns of the model of the rotating body 7 used in the experiment and a table showing the dimensions thereof. FIGS. 11A to 11C are graphs showing the relationship between the cross-sectional shape of the yoke and the magnetic force obtained by experiments. The yoke shape and dimensions were set under a constant volume condition. The yoke cross-sectional shape means a cross section cut along a plane perpendicular to the center line P.
As shown in FIG. 9, in the model of the rotating body 7, the magnet 72 is composed of a 10 mm × 10 mm double-sided quadrupole magnet having a thickness of 3 mm, and faces each other so that an attractive force acts on each other with an air gap of 3 mm. And place the magnet. A yoke face plate 73 made of permendur (soft iron) with a volume of 25 mm ³ , 50 mm ³ , and 100 mm ³ is disposed on the back side of the facing surface of the magnet 72. As shown in FIG. 10 (1), the yoke body 71 of patterns (b) to (f) was prepared so that the pattern (a) was a reference volume and the volume of the pattern (a) was constant. The change in the shape from the patterns (a) to (f) is as follows. From the yoke face plate 73 of the flat plate-shaped pattern (a) having a constant thickness, the thickness of the end portion (end portion thickness B) is 0 mm and the thickness of the central portion. Changes in the magnetic field due to a total of six types of shapes obtained by gradually decreasing the thickness of the edge until the pattern (f) where the maximum value was obtained were examined.
As shown in FIGS. 11A to 11C, in any volume, the maximum magnetic field is measured at the center point K when the end thickness B is 0 mm. The center point K is an intermediate distance point on a line connecting the centers of the opposing surfaces of the magnets 72 and 72. It can also be seen that the magnetic field strength in the air gap increases as the cross-sectional shape of the yoke approaches from a flat plate shape to a trapezoidal shape and then to a triangular shape.
Furthermore, when the yoke volume is 100 mm ^3, the magnetic field strength is almost the same when the end thickness B is 0.2 mm and when the end thickness B is 0 mm. 100 mm ³ is set, and the end face thickness B is set to 0 mm so that the thickness H of the yoke face plate 73 is maximized at the position where the magnetic poles are reversed. The maximum change in magnetic flux φ can be given to the coil winding body 61 disposed between the air gaps G. Therefore, the induced electromotive force generated in the coil winding body 61 is maximized, and the most efficient power generation can be achieved.
From the above, the yoke face plate is calculated so that the optimum volume is calculated corresponding to the strength of the magnetic flux density of the magnet used in the in-tire power generator 1 and the thickness of the yoke face plate 73 is maximized at the position where the magnetic poles are reversed. By setting the thickness of the end portion 73 to 0 mm, all the magnetic flux emitted from the unit fan-shaped magnet 77 to the adjacent unit fan-shaped magnet 77 can be passed through the yoke body 71. Therefore, the maximum magnetic flux φ is obtained between the opposing magnets 72; 72, and the coil winding body 61 passes through the magnetic flux φ, whereby efficient power generation is obtained.

本発明のタイヤ内発電装置１によれば、タイヤ内の温度や圧力タイヤ情報、例えば、タイヤにかかる圧力、路面の滑りやすさを検出し、これらタイヤの動的な状態を連続送信するために高電力を必要とするデバイスに安定して電力を供給できるようになる。 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.

なお、タイヤの内面に対するタイヤ内発電装置１の取付位置は特に限定されない。例えば、回転軸４がトレッド面の裏面と直交するようにタイヤ内発電装置１をトレッド面の裏面に取付けても良いし、回転軸４が回転方向に沿った方向に延長するようにタイヤ内発電装置１をトレッド面の裏面に取付けても良い。 In addition, the attachment position of the in-tire power generation device 1 with respect to the inner surface of the tire is not particularly limited. For example, the in-tire power generator 1 may be attached to the back surface of the tread surface so that the rotation shaft 4 is orthogonal to the back surface of the tread surface, or the in-tire power generation is performed so that the rotation shaft 4 extends in the direction along the rotation direction. You may attach the apparatus 1 to the back surface of a tread surface.

また、回転体７を、ヨーク体７１と、偏心錘を形成する磁石７２とにより構成したが、偏心錘の少なくとも重心部分が磁石により形成されていればよい。
さらに、ヨーク体７１を断面三角形状の錐体状に形成したが、ヨーク体７１の形状はこれに限らず、偏心錘としての磁石７２の形状に対応してヨーク体７１の体積が増加しないように形状を変化させればよい。 Moreover, although the rotary body 7 was comprised with the yoke body 71 and the magnet 72 which forms an eccentric weight, the gravity center part should just be formed with the magnet at least.
Furthermore, the yoke body 71 is formed in the shape of a cone having a triangular cross section. However, the shape of the yoke body 71 is not limited to this, and the volume of the yoke body 71 does not increase corresponding to the shape of the magnet 72 as an eccentric weight. What is necessary is just to change a shape.

また、上記実施形態において、１つのコイル部６に対して一対の回転体７：７を対向して配置し、当該回転体７：７及びコイル部６の組を構成するようにしたが、回転軸４に沿って並列に複数組設けるようにしても良い。 Further, in the above embodiment, a pair of rotating bodies 7: 7 are arranged opposite to one coil portion 6 to constitute a set of the rotating bodies 7: 7 and the coil portion 6. A plurality of sets may be provided in parallel along the axis 4.

以上、本発明を実施の形態を用いて説明したが、本発明の技術的範囲は上記実施の形態に記載の範囲に限定されない。上記実施の形態に、多様な変更または改良を加えることが可能である。 As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the above embodiment.

１タイヤ内発電装置、２ベース、３回転軸支持部材、４回転軸、
５コイル部固定部材、５ａ対向面、５ｂコイル部収納貫通孔、５ｃ軸避け部、
６コイル部、７回転体、１１ベース板、１２固定台、１３下板、
１４側壁、１５屋根板、１６側設置台、１７収納設置空間、１８整流回路、
１９充電回路、２０デバイス、２１軸受、２３電線、
４１端部、４２ヨーク体位置決め部、４３磁石対応部、４４軸補強部、
６０空間、６１コイル巻体、７１ヨーク体、７２磁石、
７３ヨーク面板、７３ａ扇部、７３ｂ扇の要部、７３ｕ扇面、
７４位置決め孔、７５；７６磁石位置決め板、７７単位扇形状磁石、
７８端面、７９磁石設置部、８０湾曲切欠部、
Ｂｍ最大飽和密度、Ｂｍａｇ磁束密度、Ｃ１半径線縁、Ｐ半径方向中心線。 1 In-tire power generator, 2 base, 3 rotating shaft support member, 4 rotating shaft,
5 Coil part fixing member, 5a Opposing surface, 5b Coil part storing through-hole, 5c Shaft avoiding part,
6 Coil part, 7 Rotating body, 11 Base plate, 12 Fixing base, 13 Lower plate,
14 side walls, 15 roof plate, 16 side installation stand, 17 storage installation space, 18 rectifier circuit,
19 charging circuit, 20 device, 21 bearing, 23 electric wire,
41 end portion, 42 yoke body positioning portion, 43 magnet corresponding portion, 44 shaft reinforcing portion,
60 spaces, 61 coil winding bodies, 71 yoke bodies, 72 magnets,
73 yoke face plate, 73a fan part, 73b main part of fan, 73u fan face,
74 Positioning hole, 75; 76 Magnet positioning plate, 77 Unit fan-shaped magnet,
78 end face, 79 magnet installation part, 80 curved notch part,
Bm Maximum saturation density, Bmag magnetic flux density, C1 radial edge, P radial centerline.

Claims

An in-tire power generator installed in a tire chamber,
A rotating body that is attached to the rotating shaft and is rotated in accordance with a change in force applied to the tire when the vehicle travels, partly formed by a magnet so that the center of rotation and the center of gravity are different;
A coil unit that is located between the magnets of the rotating bodies facing each other and generates a voltage by electromagnetic induction with the magnet,
The coil portion includes a coil wound body in which a coil is wound in a cylindrical shape surrounding a space through which magnetic flux generated between different magnetic poles of the magnets facing each other passes.
The rotating body includes a plurality of magnets arranged so that magnetic poles are alternately switched along a rotating direction of the rotating body, and a yoke body on a surface opposite to the surface facing the coil portion of the plurality of magnets. Prepared,
The in-tyre power generation apparatus characterized in that a thickness of the yoke body at a position where the magnetic poles of the plurality of magnets of the rotating body are reversed is set to be thicker in a rotation axis direction than a thickness of an end portion in the rotation direction of the yoke body .

The in-tire power generator according to claim 1, wherein the thickness of the yoke body is set so that the distribution of thickness in the rotation direction of the yoke body becomes a saturation magnetic field of the yoke body.

The in-tire power generator according to claim 1, wherein the coil winding body is provided in a projected portion of a rotation locus of a magnet of the rotating body.

The outer peripheral shape of the cross section of the cylinder of the coil winding body and the outer peripheral shape of the cross section of the magnet of the rotating body are formed in the same shape, and the center line of the cross section of the magnet and the cross section of the cylinder of the coil winding body are rotated by the rotation of the rotating body. The in-tire power generation according to claim 3, wherein the length of the outer periphery of the cross section of the cylinder of the coil winding body is equal to or shorter than the length of the outer periphery of the cross section of the magnet of the rotating body when the center line coincides with the center line. apparatus.

5. The in-tire power generator according to claim 1, wherein a plurality of the coil winding bodies are provided, and a rectification circuit and a charging circuit are provided for each coil winding body.

6. The magnet according to claim 1, wherein the magnet of the rotating body is symmetrical and fixed to the rotating shaft so as to face each other about the coil portion, and the rotating body and the rotating shaft rotate integrally. The in-tire power generation device described.

The yoke body includes a yoke face plate having a fan part having an angle of 180 ° or less formed by two radii of the fan and a main part of the fan part, and is perpendicular to the surface of the fan part along the outer peripheral edge of the fan part. A magnet positioning plate provided as described above, and a mounting hole for a rotating shaft in the main part of the fan part,
The yoke body forms a fan-shaped magnet installation portion surrounded by the yoke face plate and the magnet positioning plate,
The magnet is formed in a fan shape corresponding to a magnet installation portion, a curved cutout portion corresponding to an outer peripheral surface of a rotating shaft is formed at the core of the magnet fan, and the magnet is installed in the magnet installation portion. The in-tire power generation device according to any one of claims 1 to 6.

8. The mounting hole is formed in a hole having a straight line of at least one side, and a cross-sectional shape of a portion of a rotating shaft to which the mounting hole is mounted is formed in a shape corresponding to the hole. The in-tire power generator described in 1.

The in-tire power generator according to any one of claims 1 to 8, wherein the coil portion is fixed to a coil portion fixing member fixed to an inner surface of the tire via a base.

The in-tire power generator according to any one of claims 1 to 9, wherein the rotation shaft is attached to a back surface of a tread surface so as to extend in a width direction of the tire.