JP3886847B2 - Tire pressure sensor tag - Google Patents

Tire pressure sensor tag Download PDF

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Publication number
JP3886847B2
JP3886847B2 JP2002150602A JP2002150602A JP3886847B2 JP 3886847 B2 JP3886847 B2 JP 3886847B2 JP 2002150602 A JP2002150602 A JP 2002150602A JP 2002150602 A JP2002150602 A JP 2002150602A JP 3886847 B2 JP3886847 B2 JP 3886847B2
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Prior art keywords
tire
substrate
pressure sensor
antenna
sensor tag
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JP2003347811A (en
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泰 服部
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Yokohama Rubber Co Ltd
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Yokohama Rubber Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C23/00—Devices for measuring, signalling, controlling, or distributing tyre pressure or temperature, specially adapted for mounting on vehicles; Arrangement of tyre inflating devices on vehicles, e.g. of pumps or of tanks; Tyre cooling arrangements
    • B60C23/02—Signalling devices actuated by tyre pressure
    • B60C23/04—Signalling devices actuated by tyre pressure mounted on the wheel or tyre
    • B60C23/0408—Signalling devices actuated by tyre pressure mounted on the wheel or tyre transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C23/00—Devices for measuring, signalling, controlling, or distributing tyre pressure or temperature, specially adapted for mounting on vehicles; Arrangement of tyre inflating devices on vehicles, e.g. of pumps or of tanks; Tyre cooling arrangements
    • B60C23/02—Signalling devices actuated by tyre pressure
    • B60C23/04—Signalling devices actuated by tyre pressure mounted on the wheel or tyre
    • B60C23/0408—Signalling devices actuated by tyre pressure mounted on the wheel or tyre transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
    • B60C23/0422—Signalling devices actuated by tyre pressure mounted on the wheel or tyre transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver characterised by the type of signal transmission means
    • B60C23/0433—Radio signals
    • B60C23/0447—Wheel or tyre mounted circuits
    • B60C23/0452—Antenna structure, control or arrangement

Description

【０００１】
【発明の属する技術分野】
本発明は、タイヤ内圧を検知して、タイヤ内圧の状態を表す圧力情報を電波として送信する、タイヤ圧力センサタグに関する。
【０００２】
【従来の技術】
今日、車両走行を安全にするために、タイヤ内圧を検知して、タイヤ内圧の状態を車内の運転者に報知する、タイヤ空気圧監視装置が実用化されている。
このようなタイヤ空気圧監視装置は、タイヤ内圧を検知する圧力センサと、この圧力センサによって検知されたタイヤ内圧の状態を表す圧力情報を生成する処理回路と、この処理回路で生成された圧力情報を電波として送信する送信アンテナ等が設けられ、ホイールに装着されるタイヤ圧力センサタグと、タイヤ圧力センサタグから送信される電波を受信する車両側に設けられた受信アンテナと、受信アンテナに接続され、受信アンテナで受信された圧力情報に基づいて、車内の運転者にタイヤ内圧の状態を報知する受信装置とを有して構成される。
【０００３】
ここで、受信アンテナには、送信アンテナから放射され、受信アンテナに到来した電波の強さに応じた電圧が励起され、この励起電圧が所定の値以上の場合、受信アンテナに接続された受信装置では圧力情報は受信され、励起電圧が所定の値より小さい場合、圧力情報は受信されない。このため、送信アンテナから放射され伝播される電波の放射強度は、受信アンテナで安定した受信を得るために、受信アンテナの配置された位置において常時所定値以上の強さになるように設定しなければならない。
【０００４】
【発明が解決しようとする課題】
ところで、タイヤ圧力センサタグは、回転するタイヤの空洞領域に面するホイール面にタイヤ圧力センサタグの基板が装着されるため、圧力情報を送信する送信アンテナと圧力情報を受信する受信アンテナの相対的な位置は、タイヤの回転に伴って変化する。
また、従来のタイヤ圧力センサタグは、図４（図４（ａ）は従来のタイヤ圧力センサタグの斜視図、図４（ｂ）は従来のタイヤ圧力センサタグの側面図、図４（ｃ）は従来のタイヤ圧力センサタグの平面図（斜線部はアンテナ４２を示す））に示すように、構成を簡素化する点から基板４４にアンテナ４２がプリント形成された平面アンテナが一般に用いられる。そのため従来のタイヤ圧力センサは、基板４４に対して垂直方向に最大放射強度を有し、主に垂直方向に電波が放射される。
したがって、受信アンテナにおいては、タイヤの回転に伴って、送信アンテナが放射する電波の向きと距離が回転周期にしたがって繰り返し変化することになり、受信アンテナの受信する電波の強さも、タイヤの回転周期にしたがって変動する。
【０００５】
このため、例えば最大放射強度がタイヤの径方向になるように装着された従来のタイヤ圧力センサタグが、タイヤの回転に伴って最下点に到達した場合は、送信アンテナから放射される電波の向きは、主に地面方向になる。このような場合、地面方向に放射される電波は、地面で反射されるとしても、受信アンテナでの電波の強さは小さくなり、したがって受信アンテナで励起される電圧は所定値より小さくなり、受信装置が圧力情報を安定して受信できないことがあった。
【０００６】
電波法では、放射することができる電波の放射強度に限度が定められているため、このような不具合を送信アンテナから放射する電波の放射強度を強くして解決することはできない。
【０００７】
本発明は、上記問題を解決するためになされたものであり、タイヤ内圧の状態を表す圧力情報を含んだ電波を良好に安定して伝播させることのできるタイヤ圧力センサタグを提供することを課題とする。
【０００８】
【課題を解決するための手段】
本発明は前記課題を解決するために、回転するタイヤのタイヤ空洞領域に面するホイールの表面に取り付けられる基板と、この基板に設けられたタイヤ内圧を検知する圧力センサと、この圧力センサによって検知されたタイヤ内圧の状態を表す圧力情報を生成する、前記基板に設けられた処理回路と、この処理回路で生成された圧力情報を電波として送信するアンテナとを有し、前記アンテナは、帯状導体部材で構成される放射部を有し、この帯状導体部材は帯状導体部材の長手方向の少なくとも一部に面外方向の曲率を有して略ループ形状に形成され、前記基板の基板面の上方に設けられており、前記基板の周辺の４方に電波を放射することを特徴とするタイヤ圧力センサタグを提供する。
【０００９】
ここで、前記帯状導体部材の導体面の法線方向と前記基板の基板面の法線方向との成す角度は７０度以上１１０度以下であるのが好ましい。
【００１０】
【発明の実施の形態】
以下、本発明のタイヤ圧力センサタグについて、添付の図面に示される好適実施例を基に詳細を説明する。
【００１１】
図１は、本発明のタイヤ圧力センサタグ１０の概略の構成の一例を示すブロック図である。
図１に示すように、タイヤ圧力センサタグ１０は、タイヤ内圧を検出する空気圧センサ１２と、空気圧センサ１２で検出されたタイヤ内圧を表す電気信号を増幅するアナログアンプ１４と、アナログアンプ１４から送られてきた電気信号に基づいて、タイヤ内圧の状態を表す圧力情報を生成し、圧力信号として出力する処理回路１６と、処理回路１６から出力された圧力信号を搬送するための搬送波を生成し、圧力信号で変調し高周波信号を発振する発振器１８と、圧力信号で変調された搬送波を電波として放射するアンテナ２０と、これら各部を駆動するための電源を供給する電池２２と、これら各部が設けられる基板２４とを有して構成される。
【００１２】
空気圧センサ１２は、シリコンゴム等の弾性材よりなるダイヤフラムを有し、タイヤ内圧によるダイヤフラムの変形を静電容量の変化として検出してタイヤ内圧の状態を電気信号に変換するセンサでもよいし、他のタイプのセンサでもよい。なお、空気圧センサ１２は本発明の圧力センサに相当するものである。
アナログアンプ１４は、空気圧センサ１２より送られるアナログの電気信号を増幅する部分であり、公知のものである。
【００１３】
処理回路１６は、図示はしないが、記憶部、ＣＰＵ、圧力信号生成部を備え圧力情報を生成する部分である。記憶部は、空気圧センサ１２から出力される電気信号に対応する圧力情報を記憶する部分である。ＣＰＵは、アナログアンプ１４より送られる電気信号に基づいて記憶部に記憶された、電気信号に対応する圧力情報を抽出する部分である。圧力信号生成部は、ＣＰＵによって抽出された圧力情報を表す圧力信号を生成する部分である。
なお、処理回路１６は、所定の時間間隔で生成された圧力情報を表す圧力信号を生成するものでもよいし、（例えば車内の運転者による）指示入力に基づいて、圧力信号を生成するものであってもよい。
【００１４】
また、処理回路１６は、タイヤ内圧が正常であるか、異常であるかを判別した圧力情報を表す圧力信号を生成するものであってもよい。この場合、ＣＰＵは、アナログアンプ１４から送られる電気信号よりタイヤ内圧を算出し、タイヤ内圧が、記憶部に保存された内圧許容範囲内にある場合は正常であると判別し、許容範囲内にない場合は異常であると判別する。またこの場合、圧力信号生成部は、ＣＰＵによってタイヤ内圧の状態が正常であると判別された場合は、正常である旨を表す圧力信号を生成し、ＣＰＵによってタイヤ内圧の状態が異常であると判別された場合は、異常である旨を表す圧力信号を生成する。
【００１５】
発振器１８は、搬送波を生成するとともに、処理回路１６から送られてきた圧力信号に基づいて、搬送波を周波数変調し、変調した搬送波を発振させて電波として送信するためにアンテナ２０に送る部分である。なお、変調方式は、周波数変調に限定されず、振幅変調等であってもよい。
なお、搬送波の周波数帯域は、例えば３１５ＭＨｚ〜４３３ＭＨｚであり、本実施例においては、搬送波の周波数は、３７５ＭＨｚである。
【００１６】
アンテナ２０は、発振器１８から送られる、変調した搬送波を電波として送信する部分であり、本発明の特徴部分である。
【００１７】
図２（ａ）〜（ｃ）は、アンテナ２０の形状と、アンテナ２０と基板２４との位置関係を示す。なお、図２（ａ）はタイヤ圧力センサタグ１０の斜視図、図２（ｂ）はタイヤ圧力センサタグ１０の側面図、図２（ｃ）はタイヤ圧力センサタグ１０の平面図である。
ここで、基板２４には、上述の空気圧センサ１２、アナログアンプ１４、処理回路１６、発振器１８、電池２２が設けられているが、図２（ａ）〜（ｃ）では省略されている。
【００１８】
図２（ａ）〜（ｃ）に示すアンテナ２０は、電波を放射する矩形の略ループ形状の帯状導体部材より構成される放射部２０ａを有し、この帯状導体部材は、例えば幅が２ｍｍ、厚さが１００μｍであり、周長（ループ長）が５ｃｍのリン青銅である。また、この帯状導体部材の導体面の法線方向と基板２４の基板面の法線方向との成す角度は９０度であり、かつ、基板２４の基板面の２ｍｍ上方に離間して配置される。
すなわち、放射部２０ａの導体面が基板２４の基板面に対して直交するように基板２４の基板面の上方に略ループ形状に形成される。
ここで、略ループ形状とは、必ずしも周回する必要はないが、Ｕ字型、コの字型等の、基板２４の周りを囲む４方向のうちの少なくとも３方向に放射部２０ａの導体面が面するように形成された形状のことである。
【００１９】
なお、放射部２０ａの端にはアンテナ２０を支持する支持部２０ｂが接続されており、この支持部２０ｂにより放射部２０ａが基板２４の上方に設けられている。
また、２つの支持部２０ｂのうちの一方には、基板２４に設けられた発振器１８からの伝送線と接続されて給電点が形成されている。
【００２０】
このように、放射部２０ａを略ループ形状の帯状導体部材で構成することにより、図２（ａ）の矢印で示す方向に電波を放射することができる。また、放射部２０ａは略ループ形状となっているので基板２４の周辺に向かって電波を放射することができる。この点は、従来のアンテナが基板の基板面の垂直方向に最大放射強度を持って電波を放射する放射パターンと異なっている。
このようにアンテナ２０を構成することで電波を基板２４の周囲に略等方向的に放射することができ、タイヤの空洞領域内で電波を効率よく伝播させることができる。
【００２１】
なお、アンテナ２０の帯状導体部材の導体面上の法線方向と基板２４の基板面の法線方向での成す角度は９０度には限定されず、７０度〜１１０度であるのが好ましい。この範囲において、タイヤ空洞領域内で放射した電波を効率よく伝播することができる。
また、図２（ａ）〜（ｃ）に示すアンテナ２０の放射部２０ａの形状は４箇所で曲率が極めて大きくなって角を形成した矩形のループ形状であるが、放射部２０ａの形状は矩形のループ形状に限定されず、帯状導体部材の長手方向の少なくとも一部に面外方向の曲率を有するループ形状であればよく、例えば、円、楕円等の円弧のループ形状であってもよい。特に、放射部２０ａは、基板２４の基板面の法線方向に対して９０度（直角）の方向に均等に電波を放射するループ形状であるのが好ましい。
また、ループ形状はねじれた帯状導体部材によって構成されてもよいし、帯状導体部材の幅が部分的に不均一になっていてもよいし、厚さが部分的に不均一の帯状部材になっていてもよい。
【００２２】
電池２２は、基板２４に取り付けられるように、サイズの小さいボタン型電池やコイン型電池（例えばＣＲ−２０３２（コイン型二酸化マンガンリチウム電池））が用いられる。
基板２４は、シリコン基板またはガリウム砒素基板の他に、機械的支持と絶縁の目的に適した、例えば磁器、プラスチック、ガラス等の材質のものが用いられる。また、従来のタイヤ圧力センサタグの基板４４のように、アンテナ４２を基板４４に密着させる必要がなくなるため、例えば比誘電率の大きい材質に限定することなく用いることができるようになり、基板材料の選択の自由度が高くなるという利点も生じる。
【００２３】
本発明のタイヤ圧力センサタグ１０は以上のように構成される。また本実施例では、基板２４はタイヤに装着されたホイールのタイヤ空洞領域に面する表面に取り付けられる。
【００２４】
次に、本発明のタイヤ圧力センサタグ１０の作用について説明する。
タイヤ圧力センサタグ１０は、タイヤ空洞領域に面するホイールの表面に取り付けられ、タイヤの回転とともに位置が移動する。
空気圧センサ１２では、タイヤ内圧の状態が電気信号に変換され、アナログアンプ１４によって増幅され、処理回路１６に送られる。処理回路１６では、予め設定された所定の間隔で、あるいは、運転者等の指示による、受信装置から送信される指示にしたがい、図示されないＣＰＵによって、アナログアンプ１４から受け取った電気信号に対応する、圧力情報が抽出され、圧力信号生成部においてタイヤ内圧の状態を表す圧力信号が生成される。
処理回路１６で生成された圧力信号は、発振器１８に送られる。
【００２５】
発振器１８では、生成した３７５ＭＨｚの搬送波が圧力信号によって変調され、変調された搬送波は高調波信号として発振し、電波として送信されるためにアンテナ２０に送られる。
【００２６】
アンテナ２０では、発振器１８から送られた変調された３７５ＭＨｚの搬送波に基づいて、基板２４の基板面の法線方向に対して９０度（直角）の方向に最大放射強度を有する放射パターンで電波が放射される。
しかも、電波は、放射部２０ａから基板２４の周辺部に向かって４方に放射されるので、タイヤ空洞領域内に伝播される。
【００２７】
図３は、本実施例のタイヤ圧力センサタグ１０と従来のタイヤ圧力センサタグから放射された電波の、車両本体の受信アンテナの取り付けられる位置における受信レベル（電波の強さ）を同一条件で実際に測定して比較した図である。
【００２８】
図３に示されるように、従来のタイヤ圧力センサタグが用いられた場合は、時間によって、すなわちタイヤの回転周期に伴って、受信アンテナにおける電波の受信レベルが激しく変動する。したがって、受信レベルが弱くなる位置にタイヤ圧力センサタグが位置する時に電波が放射された場合は、受信装置が圧力信号を受信できるための所定の電圧よりも低い電圧しか受信アンテナにおいて励起されない。そのため、運転者にタイヤ内圧の状態を安定して報知することができない場合があった。
【００２９】
しかし、図３に示されるように、本発明によるタイヤ圧力センサタグ１０が用いられた場合は、時間によって、すなわちタイヤの回転周期によって影響を受けることは小さく、受信アンテナではほぼ一定の受信レベルで電波が受信される。したがって、タイヤ圧力センサタグ１０を用いることで、タイヤの回転に伴って位置を移動するタイヤ圧力センサタグ１０がどの位置にあっても、受信装置が圧力信号を受信できるための所定の電圧以上の電圧が励起され、車両内の運転者にタイヤ内圧の状態が安定して報知される。
【００３０】
以上、本発明のタイヤ圧力センサタグについて詳細に説明したが、本発明は上記実施例には限定されず、本発明の趣旨を逸脱しない範囲において、各種の改良および変更を行ってもよいのはもちろんである。
【００３１】
【発明の効果】
以上詳細に説明したように本発明のタイヤ圧力センサタグを用いることで、時間によって、すなわちタイヤの回転周期によって影響を受けることは小さく、受信アンテナではほぼ一定の受信レベルで電波が受信される。したがって、タイヤ圧力センサタグを用いることで、タイヤの回転に伴って位置を移動するタイヤ圧力センサタグがどの位置にあっても、受信装置が圧力信号を受信できるための所定の電圧以上の電圧が励起され、車両内の運転者にタイヤ内圧の状態が安定して報知される。このように、タイヤ内圧の状態を表す圧力情報を含んだ電波をタイヤ空洞領域で安定して良好に伝播させることができる。
【図面の簡単な説明】
【図１】 本発明のタイヤ圧力センサタグの構成の一例を示すブロック図である。
【図２】 （ａ）は本発明のタイヤ圧力センサタグの一例の斜視図、（ｂ）は本発明のタイヤ圧力センサタグの一例の側面図、（ｃ）は本発明のタイヤ圧力センサタグの一例の平面図である。
【図３】 図２に示すタイヤ圧力センサタグで得られる受信レベルの変動の一例と、従来のタイヤ圧力センサタグで得られる受信レベルの変動の一例を示した図である。
【図４】 （ａ）は従来のタイヤ圧力センサタグの斜視図、（ｂ）は従来のタイヤ圧力センサタグの側面図、（ｃ）は従来のタイヤ圧力センサタグの平面図である。
【符号の説明】
１０ タイヤ圧力センサタグ
１２ 空気圧センサ
１４ アナログアンプ
１６ 処理回路
１８ 発振器
２０，４２ アンテナ
２０ａ 放射部
２０ｂ 支持部
２２ 電池
２４，４４ 基板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tire pressure sensor tag that detects tire internal pressure and transmits pressure information representing a state of tire internal pressure as a radio wave.
[0002]
[Prior art]
2. Description of the Related Art Today, in order to make vehicle traveling safe, tire pressure monitoring devices that detect tire internal pressure and notify a driver in the vehicle of the state of tire internal pressure have been put into practical use.
Such a tire pressure monitoring device includes a pressure sensor that detects a tire internal pressure, a processing circuit that generates pressure information indicating a state of the tire internal pressure detected by the pressure sensor, and pressure information generated by the processing circuit. A transmission antenna that transmits as a radio wave is provided, a tire pressure sensor tag mounted on a wheel, a reception antenna provided on a vehicle that receives a radio wave transmitted from the tire pressure sensor tag, and a reception antenna connected to the reception antenna And a receiving device for notifying the driver in the vehicle of the state of the tire internal pressure based on the pressure information received in step (1).
[0003]
Here, a voltage corresponding to the strength of the radio wave radiated from the transmitting antenna and arriving at the receiving antenna is excited to the receiving antenna, and when the excitation voltage is a predetermined value or more, the receiving device connected to the receiving antenna Then, pressure information is received, and pressure information is not received when the excitation voltage is smaller than a predetermined value. For this reason, the radiation intensity of the radio wave radiated and propagated from the transmitting antenna must be set so that it is always more than a predetermined value at the position where the receiving antenna is arranged in order to obtain stable reception by the receiving antenna. I must.
[0004]
[Problems to be solved by the invention]
By the way, since the tire pressure sensor tag is mounted on the wheel surface facing the hollow region of the rotating tire, the relative position between the transmitting antenna that transmits pressure information and the receiving antenna that receives pressure information Changes as the tire rotates.
FIG. 4 (FIG. 4A is a perspective view of a conventional tire pressure sensor tag, FIG. 4B is a side view of the conventional tire pressure sensor tag, and FIG. 4C is a conventional tire pressure sensor tag. As shown in the plan view of the tire pressure sensor tag (the hatched portion indicates the antenna 42), a planar antenna in which the antenna 42 is printed on the substrate 44 is generally used in order to simplify the configuration. Therefore, the conventional tire pressure sensor has a maximum radiation intensity in a direction perpendicular to the substrate 44, and radio waves are mainly emitted in the vertical direction.
Therefore, in the receiving antenna, the direction and distance of the radio wave radiated from the transmitting antenna is repeatedly changed according to the rotation cycle as the tire rotates, and the strength of the radio wave received by the receiving antenna is also changed in the tire rotation cycle. It fluctuates according to.
[0005]
For this reason, for example, when a conventional tire pressure sensor tag mounted so that the maximum radiation intensity is in the tire radial direction reaches the lowest point as the tire rotates, the direction of the radio wave radiated from the transmitting antenna Is mainly in the ground direction. In such a case, even if the radio wave radiated in the direction of the ground is reflected by the ground, the intensity of the radio wave at the receiving antenna becomes small, and thus the voltage excited by the receiving antenna becomes smaller than a predetermined value, The device may not receive pressure information stably.
[0006]
According to the Radio Law, there is a limit on the radiation intensity of radio waves that can be radiated, and thus such problems cannot be solved by increasing the radiation intensity of radio waves radiated from the transmitting antenna.
[0007]
The present invention has been made to solve the above-described problem, and it is an object of the present invention to provide a tire pressure sensor tag that can satisfactorily propagate radio waves including pressure information indicating the state of tire internal pressure. To do.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a substrate attached to a wheel surface facing a tire cavity region of a rotating tire, a pressure sensor for detecting a tire internal pressure provided on the substrate, and a detection by the pressure sensor. A processing circuit provided on the substrate for generating pressure information representing a state of the tire internal pressure, and an antenna for transmitting the pressure information generated by the processing circuit as a radio wave, the antenna being a strip-shaped conductor The strip-shaped conductor member is formed in a substantially loop shape with an out-of-plane curvature at least in a part of the longitudinal direction of the strip-shaped conductor member, and is formed above the substrate surface of the substrate. A tire pressure sensor tag is provided which radiates radio waves in four directions around the substrate .
[0009]
Here, the angle formed by the normal direction of the conductor surface of the strip-shaped conductor member and the normal direction of the substrate surface of the substrate is preferably 70 degrees or more and 110 degrees or less.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the tire pressure sensor tag of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.
[0011]
FIG. 1 is a block diagram showing an example of a schematic configuration of a tire pressure sensor tag 10 of the present invention.
As shown in FIG. 1, the tire pressure sensor tag 10 is sent from the air pressure sensor 12 that detects the tire internal pressure, the analog amplifier 14 that amplifies the electric signal that represents the tire internal pressure detected by the air pressure sensor 12, and the analog amplifier 14. Based on the electrical signal thus generated, pressure information representing the state of the tire internal pressure is generated, a processing circuit 16 that outputs the pressure signal as a pressure signal, and a carrier wave for transporting the pressure signal output from the processing circuit 16 are generated. An oscillator 18 that modulates a signal and oscillates a high-frequency signal, an antenna 20 that radiates a carrier wave modulated by a pressure signal as a radio wave, a battery 22 that supplies power to drive these components, and a substrate on which these components are provided 24.
[0012]
The air pressure sensor 12 may be a sensor that has a diaphragm made of an elastic material such as silicon rubber, detects the deformation of the diaphragm due to the tire internal pressure as a change in capacitance, and converts the state of the tire internal pressure into an electric signal. This type of sensor may be used. The air pressure sensor 12 corresponds to the pressure sensor of the present invention.
The analog amplifier 14 is a part that amplifies an analog electrical signal sent from the air pressure sensor 12, and is a known one.
[0013]
Although not shown, the processing circuit 16 includes a storage unit, a CPU, and a pressure signal generation unit, and is a part that generates pressure information. The storage unit is a part that stores pressure information corresponding to the electrical signal output from the air pressure sensor 12. The CPU is a part that extracts pressure information corresponding to the electrical signal stored in the storage unit based on the electrical signal sent from the analog amplifier 14. A pressure signal generation part is a part which produces | generates the pressure signal showing the pressure information extracted by CPU.
The processing circuit 16 may generate a pressure signal representing pressure information generated at a predetermined time interval, or generate a pressure signal based on an instruction input (for example, by a driver in the vehicle). There may be.
[0014]
Further, the processing circuit 16 may generate a pressure signal that represents pressure information that determines whether the tire internal pressure is normal or abnormal. In this case, the CPU calculates the tire internal pressure from the electrical signal sent from the analog amplifier 14, and determines that the tire internal pressure is normal when the tire internal pressure is within the allowable internal pressure range stored in the storage unit. If not, it is determined that there is an abnormality. In this case, if the CPU determines that the tire pressure is normal, the pressure signal generator generates a pressure signal indicating that the tire pressure is normal, and the CPU indicates that the tire pressure is abnormal. If it is discriminated, a pressure signal indicating an abnormality is generated.
[0015]
The oscillator 18 is a part that generates a carrier wave and frequency-modulates the carrier wave based on the pressure signal sent from the processing circuit 16, and oscillates the modulated carrier wave and sends it to the antenna 20 for transmission as a radio wave. . The modulation method is not limited to frequency modulation, and may be amplitude modulation or the like.
Note that the frequency band of the carrier wave is, for example, 315 MHz to 433 MHz, and in this embodiment, the frequency of the carrier wave is 375 MHz.
[0016]
The antenna 20 is a part that transmits a modulated carrier wave transmitted from the oscillator 18 as a radio wave, and is a characteristic part of the present invention.
[0017]
2A to 2C show the shape of the antenna 20 and the positional relationship between the antenna 20 and the substrate 24. FIG. 2A is a perspective view of the tire pressure sensor tag 10, FIG. 2B is a side view of the tire pressure sensor tag 10, and FIG. 2C is a plan view of the tire pressure sensor tag 10.
Here, the air pressure sensor 12, the analog amplifier 14, the processing circuit 16, the oscillator 18, and the battery 22 are provided on the substrate 24, but are omitted in FIGS. 2 (a) to 2 (c).
[0018]
The antenna 20 shown in FIGS. 2A to 2C has a radiating portion 20a composed of a rectangular substantially loop-shaped strip-shaped conductor member that radiates radio waves, and the strip-shaped conductor member has a width of 2 mm, for example, It is phosphor bronze having a thickness of 100 μm and a circumference (loop length) of 5 cm. Further, the angle formed by the normal direction of the conductor surface of the strip-shaped conductor member and the normal direction of the substrate surface of the substrate 24 is 90 degrees, and is spaced apart by 2 mm above the substrate surface of the substrate 24. .
That is, it is formed in a substantially loop shape above the substrate surface of the substrate 24 so that the conductor surface of the radiating portion 20 a is orthogonal to the substrate surface of the substrate 24.
Here, the substantially loop shape does not necessarily circulate, but the conductor surface of the radiating portion 20a is arranged in at least three of the four directions surrounding the substrate 24, such as a U-shape and a U-shape. It is the shape formed to face.
[0019]
A support portion 20b that supports the antenna 20 is connected to the end of the radiation portion 20a, and the radiation portion 20a is provided above the substrate 24 by the support portion 20b.
One of the two support portions 20b is connected to a transmission line from the oscillator 18 provided on the substrate 24 to form a feeding point.
[0020]
Thus, by configuring the radiating portion 20a with a substantially loop-shaped strip-shaped conductor member, radio waves can be radiated in the direction indicated by the arrow in FIG. Further, since the radiating portion 20a has a substantially loop shape, radio waves can be radiated toward the periphery of the substrate 24. This is different from a radiation pattern in which a conventional antenna radiates radio waves with a maximum radiation intensity in a direction perpendicular to the substrate surface of the substrate.
By configuring the antenna 20 in this way, it is possible to radiate radio waves around the substrate 24 in a substantially isotropic direction, and it is possible to efficiently propagate radio waves within the tire cavity region.
[0021]
The angle formed between the normal direction on the conductor surface of the strip-shaped conductor member of the antenna 20 and the normal direction of the substrate surface of the substrate 24 is not limited to 90 degrees, but is preferably 70 degrees to 110 degrees. In this range, it is possible to efficiently propagate radio waves radiated within the tire cavity region.
Further, the shape of the radiating portion 20a of the antenna 20 shown in FIGS. 2A to 2C is a rectangular loop shape in which corners are formed with extremely large curvatures at four locations, but the shape of the radiating portion 20a is rectangular. The loop shape is not limited to the loop shape, and any loop shape having an out-of-plane curvature in at least a part of the longitudinal direction of the belt-like conductor member may be used. In particular, the radiating portion 20a preferably has a loop shape that radiates radio waves evenly in a direction of 90 degrees (perpendicular) with respect to the normal direction of the substrate surface of the substrate 24.
Further, the loop shape may be constituted by a twisted strip-shaped conductor member, the width of the strip-shaped conductor member may be partially non-uniform, or the thickness of the loop-shaped conductor member is partially non-uniform. It may be.
[0022]
As the battery 22, a button type battery or a coin type battery (for example, CR-2032 (coin type lithium manganese dioxide battery)) having a small size is used so as to be attached to the substrate 24.
The substrate 24 is made of a material such as porcelain, plastic or glass suitable for the purpose of mechanical support and insulation, in addition to a silicon substrate or a gallium arsenide substrate. In addition, unlike the substrate 44 of the conventional tire pressure sensor tag, the antenna 42 does not need to be in close contact with the substrate 44, so that the antenna 42 can be used without being limited to a material having a high relative dielectric constant. There is also an advantage that the degree of freedom of selection is high.
[0023]
The tire pressure sensor tag 10 of the present invention is configured as described above. In this embodiment, the substrate 24 is attached to the surface facing the tire cavity region of the wheel mounted on the tire.
[0024]
Next, the operation of the tire pressure sensor tag 10 of the present invention will be described.
The tire pressure sensor tag 10 is attached to the surface of the wheel facing the tire cavity region, and its position moves as the tire rotates.
In the air pressure sensor 12, the state of the tire internal pressure is converted into an electric signal, amplified by the analog amplifier 14, and sent to the processing circuit 16. The processing circuit 16 corresponds to an electrical signal received from the analog amplifier 14 by a CPU (not shown) at a predetermined interval set in advance or according to an instruction transmitted from the receiving device according to an instruction from a driver or the like. Pressure information is extracted, and a pressure signal representing the state of tire internal pressure is generated in the pressure signal generator.
The pressure signal generated by the processing circuit 16 is sent to the oscillator 18.
[0025]
In the oscillator 18, the generated 375 MHz carrier wave is modulated by the pressure signal, and the modulated carrier wave oscillates as a harmonic signal and is sent to the antenna 20 for transmission as a radio wave.
[0026]
In the antenna 20, the radio wave is emitted in a radiation pattern having a maximum radiation intensity in a direction of 90 degrees (perpendicular) with respect to the normal direction of the substrate surface of the substrate 24 based on the modulated 375 MHz carrier wave sent from the oscillator 18. Radiated.
Moreover, since the radio waves are radiated in four directions from the radiating portion 20a toward the peripheral portion of the substrate 24, they are propagated into the tire cavity region.
[0027]
FIG. 3 shows the actual measurement under the same conditions of the reception level (the intensity of the radio wave) of the radio wave radiated from the tire pressure sensor tag 10 of the present embodiment and the conventional tire pressure sensor tag at the position where the receiving antenna of the vehicle body is attached. FIG.
[0028]
As shown in FIG. 3, when the conventional tire pressure sensor tag is used, the reception level of the radio wave at the receiving antenna fluctuates greatly with time, that is, with the rotation cycle of the tire. Therefore, when a radio wave is emitted when the tire pressure sensor tag is located at a position where the reception level becomes weak, only a voltage lower than a predetermined voltage for allowing the receiving device to receive the pressure signal is excited at the receiving antenna. For this reason, there is a case where it is impossible to stably notify the driver of the state of the tire internal pressure.
[0029]
However, as shown in FIG. 3, when the tire pressure sensor tag 10 according to the present invention is used, it is less affected by time, that is, by the rotation period of the tire, and the reception antenna receives radio waves at a substantially constant reception level. Is received. Therefore, by using the tire pressure sensor tag 10, a voltage equal to or higher than a predetermined voltage that allows the receiving device to receive the pressure signal can be obtained regardless of the position of the tire pressure sensor tag 10 that moves as the tire rotates. When excited, the driver in the vehicle is stably notified of the state of the tire internal pressure.
[0030]
The tire pressure sensor tag of the present invention has been described in detail above. However, the present invention is not limited to the above-described embodiments, and various improvements and modifications may be made without departing from the spirit of the present invention. It is.
[0031]
【The invention's effect】
As described in detail above, by using the tire pressure sensor tag of the present invention, it is less affected by time, that is , by the rotation period of the tire, and the reception antenna receives radio waves at a substantially constant reception level. Therefore, by using the tire pressure sensor tag, a voltage higher than a predetermined voltage for exciting the receiving device to receive the pressure signal is excited regardless of the position of the tire pressure sensor tag that moves as the tire rotates. The driver in the vehicle is stably notified of the state of the tire internal pressure. In this way , radio waves including pressure information indicating the state of tire internal pressure can be stably and satisfactorily propagated in the tire cavity region.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an example of a configuration of a tire pressure sensor tag according to the present invention.
2A is a perspective view of an example of a tire pressure sensor tag of the present invention, FIG. 2B is a side view of an example of a tire pressure sensor tag of the present invention, and FIG. 2C is a plan view of an example of a tire pressure sensor tag of the present invention. FIG.
FIG. 3 is a diagram showing an example of fluctuations in reception level obtained with the tire pressure sensor tag shown in FIG. 2 and an example of fluctuations in reception level obtained with a conventional tire pressure sensor tag.
4A is a perspective view of a conventional tire pressure sensor tag, FIG. 4B is a side view of the conventional tire pressure sensor tag, and FIG. 4C is a plan view of the conventional tire pressure sensor tag.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Tire pressure sensor tag 12 Air pressure sensor 14 Analog amplifier 16 Processing circuit 18 Oscillator 20, 42 Antenna 20a Radiation part 20b Support part 22 Battery 24, 44 Board | substrate

Claims (2)

回転するタイヤのタイヤ空洞領域に面するホイールの表面に取り付けられる基板と、この基板に設けられたタイヤ内圧を検知する圧力センサと、この圧力センサによって検知されたタイヤ内圧の状態を表す圧力情報を生成する、前記基板に設けられた処理回路と、この処理回路で生成された圧力情報を電波として送信するアンテナとを有し、
前記アンテナは、帯状導体部材で構成される放射部を有し、この帯状導体部材は帯状導体部材の長手方向の少なくとも一部に面外方向の曲率を有して略ループ形状に形成され、前記基板の基板面の上方に設けられており、前記基板の周辺の４方に電波を放射することを特徴とするタイヤ圧力センサタグ。 A substrate attached to the surface of the wheel facing the tire cavity region of the rotating tire, a pressure sensor for detecting the tire internal pressure provided on the substrate, and pressure information representing the state of the tire internal pressure detected by the pressure sensor A processing circuit provided on the substrate to generate, and an antenna that transmits pressure information generated by the processing circuit as a radio wave,
The antenna has a radiating portion composed of a strip-shaped conductor member, and the strip-shaped conductor member has an out-of-plane curvature in at least a part of the longitudinal direction of the strip-shaped conductor member, and is formed in a substantially loop shape. A tire pressure sensor tag , which is provided above a substrate surface of a substrate and radiates radio waves in four directions around the substrate . 前記帯状導体部材の導体面の法線方向と前記基板の基板面の法線方向との成す角度は７０度以上１１０度以下であることを特徴とする請求項１に記載のタイヤ圧力センサタグ。  2. The tire pressure sensor tag according to claim 1, wherein an angle formed between a normal direction of a conductor surface of the strip-shaped conductor member and a normal direction of a substrate surface of the substrate is 70 degrees or more and 110 degrees or less.
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Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1681660B1 (en) 2003-11-07 2013-09-11 Kabushiki Kaisha Bridgestone Tire sensor device and tire information transmission method
JP3930024B2 (en) * 2004-02-17 2007-06-13 京セラ株式会社 Tire pressure information transmitting apparatus and wheel with tire pressure information transmitting apparatus using the same
JP4703543B2 (en) * 2004-02-17 2011-06-15 京セラ株式会社 TIRE PRESSURE INFORMATION TRANSMISSION DEVICE ANTENNA, TIRE PRESSURE INFORMATION TRANSMISSION DEVICE USING THE SAME, AND WHEEL WITH TIRE PRESSURE INFORMATION TRANSMISSION DEVICE
JP2006074369A (en) * 2004-09-01 2006-03-16 Pacific Ind Co Ltd Transmitter for tire state monitoring device, and antenna used therefor
FR2868880B1 (en) * 2004-09-02 2008-10-24 Siemens Vdo Automotive Sas ANTENNA FOR PNEUMATIC PRESSURE SENSOR AND SENSOR EQUIPPED WITH SUCH ANTENNA
US10105997B2 (en) * 2015-12-21 2018-10-23 The Goodyear Tire & Rubber Company Integrated TPMS module and RFID tag data sharing system in a tire
JP6594510B1 (en) * 2018-10-03 2019-10-23 Ｔｏｙｏ Ｔｉｒｅ株式会社 Tire and tire manufacturing method

Family Cites Families (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS573402A (en) * 1980-06-10 1982-01-08 Clarion Co Ltd Storage type antenna
JPH032712U (en) * 1989-05-31 1991-01-11
JPH05183317A (en) * 1991-12-30 1993-07-23 Casio Comput Co Ltd Loop antenna
JP3473087B2 (en) * 1993-03-29 2003-12-02 セイコーエプソン株式会社 Slot antenna device and wireless device using this antenna device
JPH07321698A (en) * 1994-04-27 1995-12-08 Texas Instr Deutschland Gmbh Extended range rf-id responder
JP3464280B2 (en) * 1994-07-06 2003-11-05 株式会社日立国際電気 Antenna for small radio receiver
KR0156300B1 (en) * 1995-04-11 1998-11-16 손일호 Loop antenna of all directions
JPH08313381A (en) * 1995-05-18 1996-11-29 Yokohama Rubber Co Ltd:The Antenna fitting structure for tire inflation pressure detector
JP2868467B2 (en) * 1996-06-17 1999-03-10 静岡日本電気株式会社 Loop antenna
JPH1065425A (en) * 1996-08-19 1998-03-06 Shinko Sangyo Kk Antenna
JPH10126140A (en) * 1996-10-15 1998-05-15 Mitsubishi Materials Corp Surface mounted antenna
JPH10270920A (en) * 1997-03-24 1998-10-09 Nec Shizuoka Ltd Antenna structure for small radio receiver
JPH10327012A (en) * 1997-03-28 1998-12-08 Mitsubishi Materials Corp Antenna system and how to use the antenna system
CA2312153A1 (en) * 1997-12-09 1999-06-17 The Goodyear Tire & Rubber Company Antenna for radio transponder
DE69725476T2 (en) * 1997-12-09 2004-07-22 The Goodyear Tire & Rubber Co., Akron TIRES WITH A TRANSPONDER AND A RING-SHAPED ANTENNA AND METHOD FOR PRODUCING SUCH A TIRE
US6208244B1 (en) * 1999-04-29 2001-03-27 Bridgestone/Firestone Research, Inc. Combination monitoring device and patch for a pneumatic tire and method of installing the same with a coupled antenna
US6388567B1 (en) * 1999-04-29 2002-05-14 Bridgestone/Firestone North American Tire, Llc Combination monitoring device and patch for a pneumatic tire and method of installing the same
JP3485044B2 (en) * 1999-10-15 2004-01-13 トヨタ自動車株式会社 Vehicle antenna device
GB2370640A (en) * 2000-08-08 2002-07-03 Transense Technologies Plc SAW device with integral patch antenna
FR2816549A1 (en) * 2000-11-13 2002-05-17 Michelin Soc Tech Remote monitoring road wheel safety insert having circumferential base wheel rim contacting and housing receiving wheel module with safety insert having integral antenna

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