JP4028350B2

JP4028350B2 - Snowfall detection device

Info

Publication number: JP4028350B2
Application number: JP2002309780A
Authority: JP
Inventors: 昇落合
Original assignee: サンポット株式会社
Priority date: 2002-10-24
Filing date: 2002-10-24
Publication date: 2007-12-26
Anticipated expiration: 2022-10-24
Also published as: JP2004144609A

Description

【０００１】
【発明の属する技術分野】
本発明は、ロードヒーティング装置、融雪マットなどの融雪装置等に付属させて使用する降雪検知装置に関する。
【０００２】
【従来の技術】
従来の降雪を検知する降雪検知装置として、基板の表面側に所定パターンの電極を配置すると共に基板の背面側にヒータを配置して、降雪で電極表面に付着した雪をヒータの発熱で融かして水にし、この水が隣接する電極間に付着することで、電極間が導通したときに流れる電気信号に基づいて降雪を検知するものが知られている（例えば、特許文献１参照。）。
【０００３】
【特許文献１】
特開平１１−５２０６５号公報
【０００４】
【発明が解決しようとする課題】
ところで、上記したような従来の降雪検知装置の電極として、例えば図７に示すように、複数の枝電極１０１ａ、１０１ｂがそれぞれ対向するような配線パターンを有する一対の電極１００ａ、１００ｂからなる検知電極１００が用いられている。
【０００５】
このような検知電極１００を用いた従来の降雪検知装置では、検知電極１００による降雪検知の感度は、一対の電極１００ａ、１００ｂの各枝電極１０１ａ、１０１ｂ間の隙間の幅及び検知面の面積が一定であるため固定されたものであった。このため、外気温による雪質の違い等によっては誤検知が生じる場合があった。
【０００６】
例えば、雪が降る条件化において地表面近くの外気温が０〜４℃位の時には、成長途中にある粒径が小さい雪の場合、或いはみぞれや雨の場合もある。この際、粒径の小さい雪は降ってもすぐにやんだり、積雪する可能性が小さいにもかかわらず、検知電極１００から降雪検知信号が制御装置（不図示）に出力され、融雪装置（不図示）を作動させる不具合が生じる場合があった。
【０００７】
そこで本発明は、外気温が高い場合や外気温が低いときでも降雪量が少ない場合における誤検知を防止することができる降雪検知装置を提供することを目的とする。
【０００８】
【課題を解決するための手段】
上記目的を達成するために本発明は、隣接する電極間がそれぞれ異なる隙間となるような配線パターンで形成された３本以上の電極を有し、通電した前記各電極間に雪融水が付着した際の導通状況に応じた電気信号を出力する検知電極と、外気温を検知する外気温検知手段と、前記外気温検知手段で検知した外気温情報に基づいて、前記検知電極の各電極のうちからそのときの降雪を検知するのに適切な隙間が得られる電極の組み合わせを選択して電気的に切換える切換え手段と、前記切換え手段で選択して切換えた組み合わせの電極から出力される電気信号に基づいて降雪状況を判定する判定手段と、を備えたことを特徴としている。
【０００９】
また、前記切換え手段は、前記外気温検知手段で検知した外気温が所定の温度範囲の場合には、前記各電極のうちから電極間の隙間が最も広い組み合わせとなる電極を選択して電気的に切換えることを特徴としている。
【００１０】
また、前記検知電極は、所定の隙間で複数の枝電極がそれぞれ交互に対向するような配線パターンを有する一対の第１、第２電極と、前記第１、第２電極の前記各枝電極間に、前記第１電極の枝電極との間の隙間と前記第２電極の枝電極との間の隙間との幅が異なるようにして配置した第３電極とで構成され、前記切換え手段は、前記外気温検知手段で検知した外気温が所定の温度範囲の場合には、最も電極間の隙間が広くなる前記第１、第２電極の前記各枝電極間で降雪を検知するように前記第１電極と前記第２電極を選択して電気的に切換えることを特徴としている。
【００１１】
また、前記切換え手段は、前記外気温検知手段で検知した外気温が前記所定の温度範囲よりも低い場合には、前記第１、第２、第３の各電極から前記第１電極と前記第２電極の組み合わせ以外の任意の組み合わせの電極を選択して電気的に切換えることを特徴としている。
【００１２】
また、最も電極間の隙間が広くなる前記第１電極と前記第２電極の組み合わせと、前記第１、第２、第３の各電極から前記第１電極と前記第２電極の組み合わせ以外の任意の１パターンの電極の組み合わせとを選択して切換える切換えスイッチを設けたことを特徴としている。
【００１３】
【発明の実施の形態】
以下、本発明を図示の実施の形態に基づいて説明する。
【００１４】
〈実施の形態１〉
図１は、本発明の実施の形態１に係る降雪検知装置を示す概略構成図である。
【００１５】
この降雪検知装置１に設置される検知電極２は、直線状の複数の枝電極３ａ、４ｂをそれぞれ有する対向配置された第１電極３と第２電極４を有し、更に、各枝電極３ａ、４ｂの間に位置するようにして配置した第３電極５を有している。第１と第２電極３、４の各枝電極３ａ、４ｂは第３電極５を間にして対向しており、各枝電極３ａ、４ｂの先端部周囲では第３電極５は直角に曲げられている。
【００１６】
検知電極２は、図２に示すように、耐環境性等に優れたセラミック材からなる基板６の表面側に公知のエッチング法によって形成されており、基板６の裏面側には公知のエッチング法によって所定パターンの発熱電極７が形成されている。また、各枝電極３ａ、４ｂを含む第１電極３と第２電極４の抵抗値は数ｋΩ程度に調整され、第３電極５の抵抗値はそれより高い数十数ｋΩ程度に調整されている。
【００１７】
図３に示すように、第１電極３の各枝電極３ａと第３電極５間の隙間ａは、１mm程度に形成されており、第２電極４の各枝電極４ａと第３電極５間の隙間ｂは、第１電極３の枝電極３ａと第３電極５間の隙間ａよりも少し広く２mm程度に形成されている。
【００１８】
第１電極３、第２電極４、第３電極５は、図１に示すように、それぞれ信号線８ａ、８ｂ、８ｃを介して切換え部９に接続されている。切換え部９には、降雪検知装置１の周囲の外気温を検知する外気温検知センサー１０、検知電極２による降雪検知の状況に応じた電流（降雪検知信号）を発生させる抵抗１１、及び比較器（コンパレータ）１２が接続されている。また、降雪検知装置１には交流電源１３が接続されている。
【００１９】
切換え部９は、外気温検知センサー１０から入力される外気温に対応した電気信号に基づいて、降雪検知を行う検知電極２を構成する第１電極３、第２電極４、第３電極５のうちから適切な検知感度が得られる組み合わせの電極を自動的に選択して電気的に切換え、選択した電極から出力される検知信号（電気信号）を取り込むことができる。
【００２０】
即ち、図４（ａ）、（ｂ）、（ｃ）、（ｄ）に示すように、図４（ａ）は、第１電極３と第２電極４を選択した場合であり、第１電極３の各枝電極３ａと第２電極４の各枝電極４ａ間で最も広い隙間が得られ、降雪の検知感度が最も低い設定となる。図４（ｂ）は、第２電極４と第３電極５を選択した場合であり、第１電極３の各枝電極３ａと第３電極５間で２番目に広い隙間が得られ、降雪の検知感度が２番目に低い設定となる。図４（ｃ）は、第１電極３と第３電極５を選択した場合であり、第１電極３の各枝電極３ａと第３電極５間で図４（ｂ）の場合よりも狭い隙間が得られ、降雪の検知感度が図４（ｂ）の場合よりも高い設定となる。
【００２１】
また、図４（ｄ）は、第１、２電極３、５と第３電極５とを選択した場合であり、第１電極３の各枝電極３ａと第２電極４の各枝電極４ａと第３電極５間で図４（ｃ）の場合よりもさらに狭い隙間が得られ、降雪の検知感度が図４（ｃ）の場合よりもさらに高い設定（降雪の検知感度が最も高い設定）となる。
【００２２】
よって、図４（ａ）の場合における電極切換えパターンでは、小さい粒径の雪は不検知となり、図４（ｂ）から図４（ｄ）の電極切換えパターンになるにつれて、より小さい粒径の雪でも検知可能となる。
【００２３】
本実施の形態では、外気温検知センサー１０で検知した外気温が−１１℃以下の場合は図４（ｄ）の電極切換えパターン、外気温検知センサー１０で検知した外気温が−６〜−１０℃の場合は図４（ｃ）の電極切換えパターン、外気温検知センサー１０で検知した外気温が−１〜−５℃以下の場合は図４（ｂ）の電極切換えパターン、外気温検知センサー１０で検知した外気温が０〜＋４℃の場合は図４（ａ）の電極切換えパターンを選択するように設定されている。なお、外気温が＋４℃以上の場合は雪ではなく雨やみぞれの場合なので、この降雪検知装置１では、降雪検知動作を行わないように設定されている。
【００２４】
なお、雪が降る条件化において外気温が比較的高い時（地表面近くの外気温が０〜４℃位）には、雪はまだ成長過程にありその粒径は小さく、雪が降る条件化において外気温が低い時には、雪の粒径は大きくなる。よって、雪が降る条件化においてその時の外気温を検知することによって、そのときの雪質を判断することができる。
【００２５】
そこで、本発明の実施の形態では、切換え部９は、外気温検知センサー１０から入力される外気温情報（外気温に応じた電気信号）に基づいてその時に降っている雪質を判断し、それに応じて適切な検知感度が得られる電極切換えパターン（図４（ａ）、（ｂ）、（ｃ）、（ｄ）のいずれか）を自動的に選択して電気的に切換える。
【００２６】
また、切換え部９は、外気温検知センサー１０から入力される外気温情報（外気温に応じた電気信号）及び選択した電極の組み合わせに応じて、比較器（コンパレータ）１２の基準電圧（基準信号）の値を可変することができる。
【００２７】
比較器（コンパレータ）１２は、切換え部９から入力される信号に基づいて可変自在な基準電圧と、上記した選択した電極切換えパターン（図４（ａ）、（ｂ）、（ｃ）、（ｄ）のいずれか）による降雪検知時に抵抗１１に流れる電流により発生する検知電圧とを取り込んで比較し、その比較結果を制御装置（不図示）に出力して降雪状態にあるか否かを判定する。
【００２８】
以下、本実施の形態に係る降雪検知装置１による降雪検知動作について説明する。
（外気温が例えば−５℃位の場合）
降雪検知装置１のスイッチ（不図示）をオンすることにより交流電源１３から降雪検知装置１に電力が供給される。そして、外気温検知センサー１０で検知した地表面近くの外気温が例えば−５℃位であると検知した場合、切換え制御部９は、外気温検知センサー１０から入力される外気温情報（外気温に応じた電気信号）に基づいて、この場合に適切な検知感度が得られる電極切換えパターン（この場合図４（ｂ））を自動的に選択して電気的に切換える。
【００２９】
切換え部９は、外気温検知センサー１０から入力される外気温情報（外気温に応じた電気信号）と選択した電極切換えパターン（第２電極４と第３電極５）情報に基づいて、この時の条件に応じて比較器１２の基準電圧（基準信号）の値を変化させる。
【００３０】
そして、所定角度で上向きに設置した表面側に検知電極２を有する基板６に降雪によって雪粒が付着すると、通電による発熱電極７の発熱によって基板６と共に検知電極２が加熱されることにより、付着した雪が溶けて水滴となる。この水滴が隣接する第２電極４の各枝電極４ａと第３電極５間に付着して電気的に導通状態となり、第２電極４と第３電極５間のインピーダンスの変化に応じて所定の電気が流れ、抵抗１１に流れる電流により発生する検知電圧が比較器１２に入力される。
【００３１】
そして、比較器１２は、この時の基準電圧（基準信号）と入力される検知電圧とを比較し、検知電圧の方が高い場合（降雪量が所定量以上の場合）には検知信号を制御装置（不図示）に出力し、制御装置からの制御信号によってロードヒーティング装置等の融雪装置（不図示）を所定時間作動させる。
【００３２】
なお、外気温が−６〜−１０℃の時の図４（ｃ）に示す電極切換えパターンの場合、及び外気温が−１１℃位以下の時の図４（ｄ）に示す電極切換えパターンの場合においても、同様にして降雪検知動作が行われる。
【００３３】
また、図４（ｄ）に示す電極切換えパターンの場合において、例えば図５に示すように、降雪によって第３電極５を挟んで第１電極３の枝電極３ａと第２電極４の枝電極４ａ間に雪が溶けた大きな水滴２０が付着した場合と、第２電極４の枝電極４と第３電極５間及び第１電極の枝電極３ａと第３電極５間にそれぞれ雪が溶けた小さな水滴２１ａ、２１ｂが付着した場合の両方とも、第３電極５を介して第１電極３と第２電極４間は導通状態となるが、本実施の形態では、第３電極５の抵抗を第１と第２電極３、４の抵抗より高くしているので、切換え部９は両者の違いを区別することができる。
（外気温が０〜＋４℃位の場合）
外気温検知センサー１０で検知した地表面近くの外気温が例えば＋３℃位であると検知した場合、切換え部９は、外気温検知センサー１０から入力される外気温情報（外気温に応じた電気信号）に基づいて、この場合に適切な検知感度が得られる電極切換えパターン（この場合図４（ａ））を自動的に選択して電気的に切換える。即ち、図４（ａ）に示すように、第１電極３と第２電極４を選択することにより、第１電極３の各枝電極３ａと第２電極４の各枝電極４ａによって最も広い隙間が得られ、降雪の検知感度が最も低い設定となる。
【００３４】
外気温が０〜＋４℃位の場合には、雪が降っても粒径が小さいことにより積もる可能性が低く、仮に積もっても外気温が高いのですぐに溶ける。よって、外気温が０〜＋４℃位の場合には、粒径の小さい雪が降ったことを検知して融雪装置を作動させるのは逆に不経済となる。
【００３５】
よって、本実施の形態では、外気温が０〜＋４℃位の場合には第１電極３と第２電極４を選択して検知感度を最も低くし、多少の降雪があった場合でも不検知となるようにして、比較器１２から制御装置（不図示）に検知信号が出力されないようにしている。
【００３６】
このように、外気温が０〜＋４℃位の場合には、切換え部９によって検知感度が最も低くなる電極切換えパターンに切換えることができるので、この条件下で降雪があっても検知信号が出力される誤動作を防止することができる。
【００３７】
また、上記の実施の形態では、図４（ａ）、（ｂ）、（ｃ）、（ｄ）にそれぞれ示した各電極切換えパターンに切換える外気温は、図４（ａ）では０〜＋４℃、図４（ｂ）では−１〜−５℃、図４（ｃ）では−６〜−１０℃、図４（ｄ）では−１１℃以下としたが、この温度範囲の設定に限定されることなく、任意の温度範囲に設定することができる。即ち、本実施の形態では、切換え部９に設けた温度範囲設定スイッチ１４を使用者が手動操作することよって、図４（ａ）、（ｂ）、（ｃ）、（ｄ）にそれぞれ示した各電極切換えパターンに切換える条件となる外気温の温度範囲の設定を任意に変更できるように構成されている。
【００３８】
特に、上記の場合は外気温が０〜＋４℃の場合において、切換え部９の切換えで図４（ａ）に示す第１電極３と第２電極４を選択する設定であったが、降雪検知装置１が設置される地域や季節などに応じて、図４（ａ）に示す第１、第２電極３、４を選択する外気温の条件を、使用者が温度範囲設定スイッチ１４を手動操作して例えば−２℃〜＋２℃に設定するようにしてもよい。このような設定により、外気温が−２℃位と低いときでも降っている雪の量が少ない場合においては、検知感度が最も低い第１、第２電極３、４の組み合わせを選択して、検知信号が出力される誤動作を防止することができる。
【００３９】
また、第１電極３の各枝電極３ａと第２電極４の各枝電極４ａと第３電極５間の各隙間の値は、上記の実施の形態における数値に限定されることなく任意の数値に設定してもよい。
【００４０】
〈実施の形態２〉
図６は、本発明の実施の形態２に係る降雪検知装置を示す概略構成図である。なお、図１に示した実施の形態１の降雪検知装置と同一機能を有する部材には同一符合を付し、重複する説明は省略する。
【００４１】
本実施の形態に係る降雪検知装置１ａには、使用者が手動で電極切換え操作する切換えスイッチ１５が切換え部９に接続されており、使用者が切換えスイッチ１５で電極切換え操作を行った場合には、図４（ａ）に示す第１、第２電極３、４と、図４（ｂ）、（ｃ）、（ｄ）のうちのいずれか一つの組み合わせ電極とを切換えることができる。他の構成及び動作は実施の形態１と同様であり、本実施の形態ではそれらの説明は省略する。
【００４２】
本実施の形態では、使用者が切換えスイッチ１５を操作することにより、図４（ａ）に示す検知感度が最も低い第１、第２電極３、４の組み合わせと、例えば図４（ｄ）に示す検知感度が最も高い第１、第２、第３電極３、４、５の組み合わせとを、降雪検知のための電極として選択する。なお、図４（ｄ）の代りに、図４（ｂ）又は図４（ｃ）に示す組み合わせ電極を選択してもよい。
【００４３】
そして、外気温検知センサー１０で検知した地表面近くの外気温が０〜＋４℃であると検知した場合、切替え部９は、外気温検知センサー１０から入力される外気温情報（外気温に応じた電気信号）に基づいて、検知感度が最も低い第１、第２電極３、４の組み合わせを選択して電気的に切換える。また、外気温検知センサー１０で検知した地表面近くの外気温が−１℃以下であると検知した場合、切換え部９は、外気温検知センサー１０から入力される外気温情報（外気温に応じた電気信号）に基づいて、検知感度が最も高い第１、第２、第３電極３、４、５の組み合わせを選択して電気的に切換える。以下、実施の形態１と同様である。
【００４４】
また、本実施の形態においても、切換え部９に設けた温度範囲設定スイッチ１４を使用者が手動操作することよって、図４（ａ）と、図４（ｄ）にそれぞれ示した各電極切換えパターンに切換える条件となる外気温の温度範囲の設定を任意に変更できる。
【００４５】
特に、上記の場合は外気温が０〜＋４℃の場合において、切換え部９の切換えで図４（ａ）に示す第１、第２電極３、４を選択する設定であったが、降雪検知装置１が設置される地域や季節などに応じて、図４（ａ）に示す第１、第２電極３、４を選択する外気温の条件を、使用者が温度範囲設定スイッチ１４を手動操作して例えば−２℃〜＋２℃に設定するようにしてもよい。この場合、−３℃以下の場合に図４（ｄ）に示す検知感度が最も高い第１、第２、第３電極３、４、５の組み合わせを選択するようにすることが好ましい。このような設定により、外気温が−２℃位と低いときでも降雪量が少ない場合においては、検知感度が最も低い第１、第２電極３、４の組み合わせを選択して、検知信号が出力される誤動作を防止することができる。
【００４６】
また、使用者が切換えスイッチ１５を操作することにより、検知感度が最も低い第１、第２電極３、４の組み合わせと、例えば検知感度が最も高い第１、第２、第３電極３、４、５の組み合わせとを、降雪検知のための電極として選択することができるので、外気温が高い場合や外気温が低いときでも降雪量が少ない場合には、検知感度が最も低い第１、第２電極３、４の組み合わせに切換えることによって、誤検知を防止することができ、逆に外気温が低い場合などには、例えば検知感度が最も高い第１、第２、第３電極３、４、５の組み合わせに切換えることによって、降雪を感度よく検知することができる。
【００４７】
【発明の効果】
以上説明したように本発明によれば、外気温検知手段で検知した外気温情報に基づいて、適切な検知感度が得られる組み合わせの電極を選択して切換えることができるので、外気温が雪が降る条件化で高い場合には降雪の検知感度が最も低くなる組み合わせの電極に切換えることにより、この場合に粒径の小さい雪が降っても検知信号が出力される誤動作を防止することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態１に係る降雪検知装置を示す概略構成図。
【図２】本発明の実施の形態１に係る降雪検知装置の検知電極を示す断面図。
【図３】本発明の実施の形態１に係る降雪検知装置の検知電極を示す平面図。
【図４】（ａ）、（ｂ）、（ｃ）、（ｄ）は、本発明の実施の形態１における電極切換えパターンを示す図。
【図５】各電極間に水滴が付着したときにおける各電極間の導通状態の違いを説明するための図。
【図６】本発明の実施の形態２に係る降雪検知装置を示す概略構成図。
【図７】従来例における降雪検知装置の検知電極を示す平面図。
【符号の説明】
１降雪検知装置
２検知電極
３第１電極
３ａ、４ａ枝電極
４第２電極
５第３電極
６基板
７発熱電極（加熱手段）
９切換え部（切換え手段）
１０外気温検知センサー（外気温検知手段）
１１抵抗
１２比較器（判定手段）
１３電源
１４温度範囲設定スイッチ
１５切換えスイッチ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a snowfall detection device used by being attached to a snowmelting device such as a road heating device or a snowmelt mat.
[0002]
[Prior art]
As a conventional snowfall detection device that detects snowfall, an electrode with a predetermined pattern is placed on the surface side of the substrate and a heater is placed on the backside of the substrate to melt the snow adhering to the electrode surface due to snowfall by the heat generated by the heater. It is known that water is detected and snowfall is detected based on an electrical signal that flows when the electrodes are connected to each other when the water adheres between adjacent electrodes (see, for example, Patent Document 1). .
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-52065
[Problems to be solved by the invention]
By the way, as an electrode of the conventional snowfall detection device as described above, for example, as shown in FIG. 7, a detection electrode comprising a pair of electrodes 100a and 100b having a wiring pattern in which a plurality of branch electrodes 101a and 101b face each other. 100 is used.
[0005]
In the conventional snowfall detection device using such a detection electrode 100, the sensitivity of snowfall detection by the detection electrode 100 is such that the width of the gap between the branch electrodes 101a and 101b of the pair of electrodes 100a and 100b and the area of the detection surface are the same. It was fixed because it was constant. For this reason, erroneous detection may occur depending on the difference in snow quality depending on the outside temperature.
[0006]
For example, when the outside air temperature near the ground surface is about 0 to 4 ° C. under conditions of snowfall, there may be a case where the particle diameter is small during the growth, or a sleet or rain. At this time, even if snow with a small particle size falls, the snow detection signal is output from the detection electrode 100 to the control device (not shown), even though it is unlikely to immediately stop or accumulate snow. There was a case where a problem occurred in operating the figure.
[0007]
Therefore, an object of the present invention is to provide a snowfall detection device capable of preventing erroneous detection when the outside air temperature is high or when the amount of snowfall is small even when the outside air temperature is low.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has three or more electrodes formed in a wiring pattern such that adjacent electrodes have different gaps, and snow melt adheres between the energized electrodes. A detection electrode that outputs an electrical signal according to the conduction state at the time of operation, an outside air temperature detection means that detects the outside air temperature, and the outside air temperature information detected by the outside air temperature detection means, Switching means for selecting and electrically switching a combination of electrodes that can provide an appropriate gap for detecting snowfall at that time, and an electric signal output from the combination of electrodes selected and switched by the switching means And determining means for determining a snowfall condition based on the above.
[0009]
In addition, when the outside air temperature detected by the outside air temperature detecting means is within a predetermined temperature range, the switching means selects the electrode having the widest gap between the electrodes from among the electrodes, and It is characterized by switching to.
[0010]
The detection electrode includes a pair of first and second electrodes having a wiring pattern in which a plurality of branch electrodes alternately face each other with a predetermined gap, and between the branch electrodes of the first and second electrodes. And a third electrode arranged such that the width of the gap between the branch electrode of the first electrode and the gap between the branch electrode of the second electrode is different, and the switching means includes: When the outside air temperature detected by the outside air temperature detecting means is within a predetermined temperature range, the first so as to detect snowfall between the branch electrodes of the first and second electrodes where the gap between the electrodes is widest. One electrode and the second electrode are selected and electrically switched.
[0011]
In addition, when the outside air temperature detected by the outside air temperature detecting unit is lower than the predetermined temperature range, the switching unit is configured to switch the first electrode and the first electrode from the first, second, and third electrodes. An electrode having an arbitrary combination other than the combination of two electrodes is selected and electrically switched.
[0012]
In addition, any combination other than the combination of the first electrode and the second electrode with the widest gap between the electrodes and the combination of the first electrode and the second electrode from the first, second, and third electrodes This is characterized in that a change-over switch for selecting and switching the combination of one pattern electrode is provided.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on the illustrated embodiments.
[0014]
<Embodiment 1>
FIG. 1 is a schematic configuration diagram showing a snowfall detection device according to Embodiment 1 of the present invention.
[0015]
The detection electrode 2 installed in the snowfall detection device 1 has a first electrode 3 and a second electrode 4 arranged to face each other, each having a plurality of linear branch electrodes 3a and 4b, and each branch electrode 3a. 4b, the third electrode 5 is disposed so as to be positioned between the four electrodes 4b. The branch electrodes 3a and 4b of the first and second electrodes 3 and 4 are opposed to each other with the third electrode 5 therebetween, and the third electrode 5 is bent at a right angle around the tip of each branch electrode 3a and 4b. ing.
[0016]
As shown in FIG. 2, the detection electrode 2 is formed on the front surface side of the substrate 6 made of a ceramic material having excellent environmental resistance and the like, and a known etching method is formed on the back surface side of the substrate 6. Thus, a heating electrode 7 having a predetermined pattern is formed. Further, the resistance value of the first electrode 3 and the second electrode 4 including the branch electrodes 3a and 4b is adjusted to about several kΩ, and the resistance value of the third electrode 5 is adjusted to about several tens of kΩ higher than that. Yes.
[0017]
As shown in FIG. 3, the gap a between each branch electrode 3 a of the first electrode 3 and the third electrode 5 is formed to be about 1 mm, and between each branch electrode 4 a of the second electrode 4 and the third electrode 5. The gap b is formed to be about 2 mm slightly wider than the gap a between the branch electrode 3 a of the first electrode 3 and the third electrode 5.
[0018]
As shown in FIG. 1, the first electrode 3, the second electrode 4, and the third electrode 5 are connected to the switching unit 9 through signal lines 8a, 8b, and 8c, respectively. The switching unit 9 includes an outside air temperature detection sensor 10 for detecting the outside air temperature around the snowfall detection device 1, a resistor 11 for generating a current (snowfall detection signal) corresponding to the snowfall detection status by the detection electrode 2, and a comparator. (Comparator) 12 is connected. An AC power supply 13 is connected to the snowfall detection device 1.
[0019]
The switching unit 9 includes a first electrode 3, a second electrode 4, and a third electrode 5 that constitute the detection electrode 2 that performs snowfall detection based on an electric signal corresponding to the outside air temperature input from the outside air temperature detection sensor 10. It is possible to automatically select and electrically switch a combination of electrodes capable of obtaining appropriate detection sensitivity from among them, and to capture a detection signal (electric signal) output from the selected electrode.
[0020]
That is, as shown in FIGS. 4A, 4B, 4C, and 4D, FIG. 4A shows the case where the first electrode 3 and the second electrode 4 are selected. 3, the widest gap is obtained between each branch electrode 3 a and each branch electrode 4 a of the second electrode 4, and the detection sensitivity of snowfall is set to the lowest. FIG. 4B shows a case where the second electrode 4 and the third electrode 5 are selected, and the second widest gap is obtained between each branch electrode 3a of the first electrode 3 and the third electrode 5, and snowfall is caused. The detection sensitivity is the second lowest setting. FIG. 4C shows the case where the first electrode 3 and the third electrode 5 are selected, and the gap between each branch electrode 3a of the first electrode 3 and the third electrode 5 is narrower than in the case of FIG. 4B. Is obtained, and the detection sensitivity of snowfall is set higher than in the case of FIG.
[0021]
FIG. 4D shows a case where the first, second electrodes 3 and 5 and the third electrode 5 are selected. Each branch electrode 3a of the first electrode 3 and each branch electrode 4a of the second electrode 4 A narrower gap is obtained between the third electrodes 5 than in the case of FIG. 4C, and the snow detection sensitivity is set higher than that in FIG. 4C (the snow detection sensitivity is the highest setting). Become.
[0022]
Therefore, in the electrode switching pattern in the case of FIG. 4A, snow with a small particle size is not detected, and as the electrode switching pattern is changed from FIG. 4B to FIG. But it can be detected.
[0023]
In the present embodiment, when the outside air temperature detected by the outside air temperature detection sensor 10 is −11 ° C. or less, the outside air temperature detected by the electrode switching pattern of FIG. 4D and the outside air temperature detection sensor 10 is −6 to −10. 4C, the electrode switching pattern shown in FIG. 4C. When the outside air temperature detected by the outside air temperature detection sensor 10 is -1 to -5.degree. C. or less, the electrode switching pattern shown in FIG. When the outside air temperature detected at 0 is 0 to + 4 ° C., the electrode switching pattern shown in FIG. 4A is selected. When the outside air temperature is + 4 ° C. or higher, it is rain or sleet instead of snow. Therefore, the snowfall detection device 1 is set not to perform the snowfall detection operation.
[0024]
Note that when the outside air temperature is relatively high (conditions where the snow falls) (the outside air temperature near the ground surface is about 0 to 4 ° C), the snow is still growing and its particle size is small. When the temperature is low, the snow particle size increases. Therefore, the snow quality at that time can be judged by detecting the outside air temperature at that time in the condition that snow falls.
[0025]
Therefore, in the embodiment of the present invention, the switching unit 9 determines the snow quality falling at that time based on the outside air temperature information (electrical signal corresponding to the outside air temperature) input from the outside air temperature detection sensor 10, In response to this, an electrode switching pattern (any one of FIGS. 4A, 4B, 4C, and 4D) capable of obtaining appropriate detection sensitivity is automatically selected and electrically switched.
[0026]
In addition, the switching unit 9 determines the reference voltage (reference signal) of the comparator (comparator) 12 in accordance with the outside air temperature information (electric signal according to the outside air temperature) input from the outside air temperature detection sensor 10 and the selected combination of electrodes. ) Value can be varied.
[0027]
The comparator (comparator) 12 includes a reference voltage that is variable based on a signal input from the switching unit 9 and the selected electrode switching pattern (see FIGS. 4A, 4B, 4C, and 4D). The detection voltage generated by the current flowing through the resistor 11 at the time of snowfall detection according to any of the above) is taken in and compared, and the comparison result is output to a control device (not shown) to determine whether or not it is in a snowfall state. .
[0028]
Hereinafter, the snowfall detection operation by the snowfall detection apparatus 1 according to the present embodiment will be described.
(When the outside air temperature is around -5 ° C, for example)
By turning on a switch (not shown) of the snowfall detection device 1, power is supplied from the AC power supply 13 to the snowfall detection device 1. When the outside air temperature detected by the outside air temperature detection sensor 10 is detected to be, for example, about −5 ° C., the switching control unit 9 receives the outside air temperature information (outside air temperature) input from the outside air temperature detection sensor 10. In this case, an electrode switching pattern (in this case, FIG. 4B) that can obtain appropriate detection sensitivity is automatically selected and electrically switched.
[0029]
Based on the outside air temperature information (electrical signal corresponding to the outside air temperature) input from the outside air temperature detection sensor 10 and the selected electrode switching pattern (second electrode 4 and third electrode 5) information, the switching unit 9 at this time The value of the reference voltage (reference signal) of the comparator 12 is changed according to the above condition.
[0030]
Then, when snow particles adhere to the substrate 6 having the detection electrode 2 on the surface side that is installed upward at a predetermined angle due to snowfall, the detection electrode 2 is heated together with the substrate 6 by the heat generation of the heat generation electrode 7 by energization. The melted snow melts into water droplets. This water droplet adheres between each branch electrode 4a of the adjacent second electrode 4 and the third electrode 5 and becomes electrically conductive, and a predetermined amount is determined according to a change in impedance between the second electrode 4 and the third electrode 5. Electricity flows, and a detection voltage generated by a current flowing through the resistor 11 is input to the comparator 12.
[0031]
Then, the comparator 12 compares the reference voltage (reference signal) at this time with the input detection voltage, and controls the detection signal when the detection voltage is higher (when the amount of snowfall is a predetermined amount or more). It outputs to a device (not shown), and a snow melting device (not shown) such as a road heating device is operated for a predetermined time by a control signal from the control device.
[0032]
In the case of the electrode switching pattern shown in FIG. 4C when the outside air temperature is −6 to −10 ° C. and the case of the electrode switching pattern shown in FIG. 4D when the outside air temperature is about −11 ° C. or less. Even in this case, the snowfall detection operation is performed in the same manner.
[0033]
In the case of the electrode switching pattern shown in FIG. 4D, for example, as shown in FIG. 5, the branch electrode 3a of the first electrode 3 and the branch electrode 4a of the second electrode 4 sandwiching the third electrode 5 by snowfall. In the case where a large water droplet 20 in which snow has melted adheres, a small water droplet 21a in which snow has melted, between the branch electrode 4 and the third electrode 5 of the second electrode 4 and between the branch electrode 3a and the third electrode 5 of the first electrode, respectively. In this embodiment, the first electrode 3 and the second electrode 4 are electrically connected via the third electrode 5, but in the present embodiment, the resistance of the third electrode 5 is set to the first and second electrodes 5 and 21b. Since the resistance is higher than the resistance of the second electrodes 3 and 4, the switching unit 9 can distinguish the difference between them.
(When the outside temperature is about 0 to + 4 ° C)
When the outside air temperature detected by the outside air temperature detection sensor 10 detects that the outside air temperature near the ground surface is, for example, about + 3 ° C., the switching unit 9 receives the outside air temperature information (electricity according to the outside air temperature) input from the outside air temperature detection sensor 10. In this case, an electrode switching pattern (in this case, FIG. 4A) that can obtain an appropriate detection sensitivity is automatically selected and electrically switched. That is, as shown in FIG. 4A, by selecting the first electrode 3 and the second electrode 4, the widest gap between each branch electrode 3a of the first electrode 3 and each branch electrode 4a of the second electrode 4 is obtained. Is obtained and the detection sensitivity for snowfall is the lowest.
[0034]
When the outside air temperature is about 0 to + 4 ° C., even if it snows, it is less likely to accumulate due to the small particle size, and even if it accumulates, the outside air temperature is high and melts immediately. Accordingly, when the outside air temperature is about 0 to + 4 ° C., it is uneconomical to operate the snow melting device by detecting that snow having a small particle size has fallen.
[0035]
Therefore, in this embodiment, when the outside air temperature is about 0 to + 4 ° C., the first electrode 3 and the second electrode 4 are selected to make the detection sensitivity the lowest, and even if there is some snowfall, no detection is made. Thus, the detection signal is not output from the comparator 12 to the control device (not shown).
[0036]
In this way, when the outside air temperature is about 0 to + 4 ° C., the switching unit 9 can switch to the electrode switching pattern with the lowest detection sensitivity, so that a detection signal is output even if there is snowfall under this condition. Malfunction can be prevented.
[0037]
In the above embodiment, the outside air temperature to be switched to each electrode switching pattern shown in FIGS. 4A, 4B, 4C, and 4D is 0 to + 4 ° C. in FIG. 4 (b), -1 to -5 [deg.] C., FIG. 4 (c), -6 to -10 [deg.] C., and FIG. 4 (d), -11 [deg.] C. or lower. It can set to arbitrary temperature ranges, without. That is, in the present embodiment, the temperature range setting switch 14 provided in the switching unit 9 is manually operated by the user, as shown in FIGS. 4 (a), (b), (c), and (d), respectively. The setting of the temperature range of the outside air temperature, which is a condition for switching to each electrode switching pattern, can be arbitrarily changed.
[0038]
In particular, in the above case, when the outside air temperature is 0 to + 4 ° C., the setting of selecting the first electrode 3 and the second electrode 4 shown in FIG. The user manually operates the temperature range setting switch 14 according to the conditions of the outside air temperature for selecting the first and second electrodes 3 and 4 shown in FIG. For example, it may be set to -2 ° C to + 2 ° C. With such a setting, when the amount of snow falling is small even when the outside air temperature is as low as −2 ° C., the combination of the first and second electrodes 3 and 4 having the lowest detection sensitivity is selected. A malfunction in which a detection signal is output can be prevented.
[0039]
Further, the value of each gap between each branch electrode 3a of the first electrode 3 and each branch electrode 4a of the second electrode 4 and the third electrode 5 is not limited to the numerical value in the above-described embodiment, and may be any numerical value. May be set.
[0040]
<Embodiment 2>
FIG. 6 is a schematic configuration diagram illustrating a snowfall detection device according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as the snowfall detection apparatus of Embodiment 1 shown in FIG. 1, and the overlapping description is abbreviate | omitted.
[0041]
In the snowfall detection device 1a according to the present embodiment, a changeover switch 15 that is manually operated by the user to switch electrodes is connected to the switching unit 9, and the user performs an electrode changeover operation using the changeover switch 15. Can switch between the first and second electrodes 3 and 4 shown in FIG. 4A and any one of the combination electrodes shown in FIGS. 4B, 4C and 4D. Other configurations and operations are the same as those in the first embodiment, and a description thereof is omitted in this embodiment.
[0042]
In the present embodiment, when the user operates the changeover switch 15, the combination of the first and second electrodes 3 and 4 having the lowest detection sensitivity shown in FIG. The combination of the first, second, and third electrodes 3, 4, 5 having the highest detection sensitivity is selected as an electrode for detecting snowfall. Instead of FIG. 4D, a combination electrode shown in FIG. 4B or 4C may be selected.
[0043]
When the outside air temperature detected by the outside air temperature detection sensor 10 detects that the outside air temperature near the ground surface is 0 to + 4 ° C., the switching unit 9 receives the outside air temperature information input from the outside air temperature detection sensor 10 (according to the outside air temperature). The combination of the first and second electrodes 3 and 4 having the lowest detection sensitivity is selected and electrically switched. When the outside air temperature detected by the outside air temperature detection sensor 10 is detected to be −1 ° C. or lower, the switching unit 9 receives the outside air temperature information input from the outside air temperature detection sensor 10 (according to the outside air temperature). The combination of the first, second, and third electrodes 3, 4, and 5 having the highest detection sensitivity is selected and electrically switched. Hereinafter, it is the same as that of Embodiment 1.
[0044]
Also in the present embodiment, when the user manually operates the temperature range setting switch 14 provided in the switching unit 9, the electrode switching patterns shown in FIGS. 4 (a) and 4 (d), respectively. The setting of the temperature range of the outside air temperature, which is the condition for switching to, can be arbitrarily changed.
[0045]
In particular, in the above case, when the outside air temperature is 0 to + 4 ° C., the setting of selecting the first and second electrodes 3 and 4 shown in FIG. The user manually operates the temperature range setting switch 14 according to the conditions of the outside air temperature for selecting the first and second electrodes 3 and 4 shown in FIG. For example, it may be set to -2 ° C to + 2 ° C. In this case, it is preferable to select the combination of the first, second, and third electrodes 3, 4, and 5 having the highest detection sensitivity shown in FIG. With such a setting, when the amount of snowfall is small even when the outside air temperature is as low as −2 ° C., the combination of the first and second electrodes 3 and 4 having the lowest detection sensitivity is selected and a detection signal is output. Malfunction can be prevented.
[0046]
Further, when the user operates the changeover switch 15, the combination of the first and second electrodes 3 and 4 having the lowest detection sensitivity and the first, second and third electrodes 3 and 4 having the highest detection sensitivity, for example. 5 can be selected as an electrode for detecting snowfall. Therefore, when the outside air temperature is high or when the outside air temperature is low, the amount of snowfall is small. Switching to a combination of two electrodes 3 and 4 can prevent erroneous detection. Conversely, when the outside air temperature is low, for example, the first, second and third electrodes 3 and 4 having the highest detection sensitivity. By switching to the combination of 5, it is possible to detect snowfall with high sensitivity.
[0047]
【The invention's effect】
As described above, according to the present invention, it is possible to select and switch a combination of electrodes that provide appropriate detection sensitivity based on the outside air temperature information detected by the outside air temperature detecting means, so that the outside air temperature is snowed. When the condition is high, switching to a combination of electrodes having the lowest snowfall detection sensitivity can prevent a malfunction in which a detection signal is output even when snow with a small particle size falls.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a snowfall detection device according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a detection electrode of the snowfall detection device according to the first embodiment of the present invention.
FIG. 3 is a plan view showing a detection electrode of the snowfall detection device according to the first embodiment of the present invention.
FIGS. 4A, 4B, 4C, and 4D are diagrams showing an electrode switching pattern according to Embodiment 1 of the present invention. FIGS.
FIG. 5 is a diagram for explaining a difference in conduction state between electrodes when water droplets adhere between the electrodes;
FIG. 6 is a schematic configuration diagram showing a snowfall detection device according to a second embodiment of the present invention.
FIG. 7 is a plan view showing detection electrodes of a snowfall detection device in a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Snowfall detection apparatus 2 Detection electrode 3 1st electrode 3a, 4a Branch electrode 4 2nd electrode 5 3rd electrode 6 Substrate 7 Heating electrode (heating means)
9 Switching section (switching means)
10 Outside air temperature detection sensor (outside air temperature detection means)
11 Resistance 12 Comparator (determination means)
13 Power supply 14 Temperature range setting switch 15 Changeover switch

Claims

There are three or more electrodes formed in a wiring pattern so that adjacent electrodes have different gaps, and an electrical signal corresponding to the conduction state when snow melt adheres between the energized electrodes. A sensing electrode to output,
An outside air temperature detecting means for detecting the outside air temperature,
Based on the outside air temperature information detected by the outside air temperature detecting means, an electrode combination that provides an appropriate gap for detecting snowfall at that time is selected from among the electrodes of the detection electrode and electrically switched. Switching means;
Determination means for determining a snowfall situation based on an electric signal output from the combination of electrodes selected and switched by the switching means,
A snowfall detecting device characterized by that.

When the outside air temperature detected by the outside air temperature detecting means is within a predetermined temperature range, the switching means selects and electrically switches the electrode having the widest gap between the electrodes from the electrodes. ,
The snowfall detection device according to claim 1.

The detection electrode includes a pair of first and second electrodes having a wiring pattern in which a plurality of branch electrodes alternately face each other with a predetermined gap, and between the branch electrodes of the first and second electrodes, A third electrode arranged such that a gap between the branch electrode of the first electrode and a gap between the branch electrode of the second electrode has a different width, and the switching means includes the outer electrode When the outside air temperature detected by the air temperature detecting means is in a predetermined temperature range, the first electrode is configured to detect snowfall between the branch electrodes of the first and second electrodes that have the widest gap between the electrodes. And the second electrode is selected and electrically switched,
The snowfall detection device according to claim 1, wherein:

When the outside air temperature detected by the outside air temperature detecting unit is lower than the predetermined temperature range, the switching unit is configured to switch the first electrode and the second electrode from the first, second, and third electrodes. Select and electrically switch electrodes in any combination other than
The snowfall detecting device according to claim 3.

Arbitrary 1 other than the combination of the first electrode and the second electrode with the widest gap between the electrodes, and the combination of the first electrode and the second electrode from the first, second and third electrodes A change-over switch is provided to select and switch the pattern electrode combination.
The snowfall detecting device according to claim 3 or 4, wherein