JP3959895B2

JP3959895B2 - Eddy current reducer

Info

Publication number: JP3959895B2
Application number: JP20776699A
Authority: JP
Inventors: 徹桑原
Original assignee: Isuzu Motors Ltd
Current assignee: Isuzu Motors Ltd
Priority date: 1999-07-22
Filing date: 1999-07-22
Publication date: 2007-08-15
Anticipated expiration: 2019-07-22
Also published as: JP2001037204A

Description

【発明の属する技術分野】
【０００１】
本発明は車両などの摩擦ブレーキを補助する渦電流減速装置、特に制動ドラムの両端部に銅などの良伝導体を結合することにより、渦電流の流れを改善し制動力を向上するようにした渦電流減速装置に関するものである。
【従来の技術】
【０００２】
従来の渦電流減速装置は、鋼鉄、低炭素鋼などの導体からなる制動ドラムの内部に磁石支持筒を配設し、磁石支持筒の外周面に周方向等間隔かつ制動ドラム内周面に対する極性が周方向交互に異なるように結合した磁石（電磁石を含む）を、制動ドラムの内周面に接近させると、回転する制動ドラムが磁石からの磁界を横切り、渦電流に基づく制動力が制動ドラムに発生する。制動ドラムの両端部にニツケルめっき層を介して、銅などの良伝導体からなる環状体（筒体または環状板）を結合すると、渦電流の流れが改善され、制動能力が向上する。
【０００３】
しかし、制動時、渦電流が良伝導体からなる環状体に集中し、良伝導体からなる環状体の温度は、制動ドラムの内周面の軸方向中央部分の温度との差が殆どなくなる。６００℃を超える高温では、良伝導体からなる環状体を構成する銅よりも、制動ドラムを構成する低炭素鋼の方が耐熱性に優れるので、結局良伝導体からなる環状体の温度により渦電流減速装置の運転域が制限され、良伝導体からなる環状体を備えた制動ドラムの制動性能を十分に発揮できない。つまり、良伝導体からなる環状体が過熱状態になると、環状体が割れたり制動ドラムから剥離するなどの障害が生じるので、制動能力の向上には限度がある。したがつて、制動能力のさらなる向上には、良伝導体からなる環状体の温度上昇を抑えることが要求される。
【発明が解決しようとする課題】
【０００４】
本発明の課題は上述の問題に鑑み、良伝導体の体積増大により熱容量を大きくし、かつ外気による冷却性を高めて、良伝導体の温度上昇を抑えるようにした渦電流減速装置を提供することにある。
【課題を解決するための手段】
【０００５】
上記課題を解決するために、本発明の構成は回転軸に結合した導体からなる制動ドラムと、該制動ドラムの内部へ臨むように車体などの非回転部分に取り付けた断面長方形の内空部を有する非磁性体からなる案内筒と、該案内筒の内空部に収容した少くとも１つが回動可能の磁石支持筒と、該磁石支持筒の外周面に周方向等間隔に結合した多数の磁石と、前記案内筒の外筒部に前記各磁石と対向して鋳込んだ強磁性板とを有し、前記磁石からの磁界により渦電流に基づく制動力を前記制動ドラムに発生させる渦電流減速装置において、前記制動ドラムの内周面の前記強磁性板に対向しない端部と前記制動ドラムの端壁面とに連続して、銅などの良伝導体からなる環状体を結合し、前記制動ドラムの端壁面の環状体の肉厚よりも前記制動ドラムの内周面の環状体の肉厚を厚くし、前記制動ドラムの内周面の環状体に多数の軸方向の溝を周方向等間隔に設けたことを特徴とする。
【０００６】
また、本発明の構成は回転軸に結合した導体からなる制動ドラムと、該制動ドラムの内部へ半部が臨むように車体などの非回転部分に取り付けた断面長方形の内空部を有する案内筒と、該案内筒の内空部に軸方向移動可能に収容した磁石支持筒と、該磁石支持筒の外周面に周方向等間隔に結合した多数の磁石と、前記案内筒の外筒部の前記制動ドラムの内周面と対向しない磁性体からなる部分と、非磁性体からなる前記案内筒の外筒部の前記制動ドラムの内周面と対向しかつ前記各磁石と対向する部分に鋳込んだ強磁性板とを有し、前記磁石からの磁界により渦電流に基づく制動力を前記制動ドラムに発生させる渦電流減速装置において、前記制動ドラムの内周面の前記強磁性板に対向しない端部と前記制動ドラムの端壁面とに連続して、銅などの良伝導体からなる環状体を結合し、前記制動ドラムの端壁面の環状体の肉厚よりも前記制動ドラムの内周面の環状体の肉厚を厚くし、前記制動ドラムの内周面の環状体に多数の軸方向の溝を周方向等間隔に設けたことを特徴とする。
【発明の実施の形態】
【０００７】
本発明では制動ドラムの内周面の両端部と制動ドラムの両端壁面とに、銅などの良伝導体からなる断面Ｌ字形の環状体を結合し、特に放熱性の良くない内周面に結合される環状体の肉厚を、端壁面に結合される環状体のそれよりも厚くすることにより渦電流の密度を小さくし、ジユール熱による環状体の温度上昇を抑える。また、制動ドラムの内周面に結合される環状体の放熱性を高めるために、環状体に多数の軸方向の溝を周方向に間隔を存して設ける。制動ドラムが回転する時、環状体が羽根車として働き、外気を環状体へ導いて冷却する。
【実施例】
【０００８】
図１は本発明に係る渦電流減速装置の正面断面図、図２は同渦電流減速装置の側面断面図である。渦電流減速装置は例えば車両用変速機の出力回転軸２１に結合される鋼鉄などの導体からなる制動ドラム１５と、制動ドラム１５の内部に配設される非磁性体からなる案内筒６と、案内筒６の断面長方形の内空部２０に収容した可動の磁石支持筒９および不動の磁石支持筒９ａとを備えている。制動ドラム１５はボス１９のフランジ部１９ａを、駐車ブレーキの制動ドラム２３の端壁と一緒に、回転軸２１のスプライン２２ａに嵌合されかつナツト２１ａにより締結した取付フランジ２２に重ね合され、かつ複数のボルト２４とナツトにより締結される。ボス１９から放射状に延びる多数の支持腕１６に、冷却フイン１５ａを備えた制動ドラム１５の基端が結合される。制動ドラム１５の内周面１５ｂの両端部には、銅などの良伝導体からなる環状体４１，４２と環状体４３，４４が結合され、制動ドラム１５の渦電流の流れを軸方向に広め制動力を高める。
【０００９】
案内筒６は例えば断面Ｃ字形の非磁性体からなる筒体に、環状板からなる端壁６ｄを結合して構成される。案内筒６は適当な手段により非回転部分、例えば変速機の歯車箱に固定される。案内筒６の外筒部６ａには周方向等間隔に設けた多数の開口３２に、抜止め突条３１ａを有する強磁性板３１を結合される。好ましくは、強磁性板３１は案内筒６の鋳造による成形時鋳込まれる。強磁性板３１は長方形の板状のものであつて、板面は円弧状に湾曲される。
【００１０】
磁性体からなる可動の磁石支持筒９は案内筒６の内空部２０にあつて、滑り軸受またはコロ軸受３５により正逆回動可能に内筒部６ｂに支持される。磁石支持筒９から軸方向へ延びる腕３４は、案内筒６の端壁６ｃに設けた円弧状のスリツト３３を経て、アクチユエータＡのロツドに連結される。磁石支持筒９は外周面に各強磁性板３１の左半部に対向する多数の磁石８を、各強磁性板３１に対する極性が周方向交互に異なるように結合される。一方、磁性体からなる不動の磁石支持筒９ａは案内筒６の内空部２０にあつて内筒部６ｂに固定され、外周面に各強磁性板３１の右半部に対向する磁石８と同数の磁石８ａを、各強磁性板３１に対する極性が周方向交互に異なるように結合される。案内筒６の端壁６ｃに、複数のアクチユエータＡが周方向等間隔に結合される。アクチユエータＡはシリンダ２にピストン４を嵌装してなり、ピストン４から外部へ突出するロツドは腕３４と連結される。
【００１１】
図２に示すように、磁石支持筒９ａの磁石８ａは、内面と外面がそれぞれ円筒面をなし、各磁石８ａの周方向の端部に形成した段部２６の間へ、非磁性体からなる断面Ｔ字形の固定金具２７を係合し、ボルト２８により磁石支持筒９ａへ締結される。
【００１２】
次に、本発明による渦電流減速装置の作動について説明する。非制動時、図１に示すように、磁石支持筒９の磁石８と磁石支持筒９ａの磁石８ａとは、強磁性板３１に対向する極性が互いに逆になつている。この時、磁石８，８ａは各強磁性板３１と磁石支持筒９，９ａとの間に、短絡的磁気回路ｗを形成し、制動ドラム１５に磁界を及ぼさない。制動時、アクチユエータＡにより磁石支持筒９を非制動位置から図２に示す制動位置へ磁石８の配列ピツチだけ回動すると、軸方向に並ぶ磁石８，８ａは各強磁性板３１に対向する極性が同じになり、強磁性板３１を経て制動ドラム１５に磁界を及ぼす。回転する制動ドラム１５が磁界を横切る時、制動ドラム１５に渦電流が流れ、制動ドラム１５は制動トルクを発生する。この時、各磁石８，８ａは制動ドラム１５と磁石支持筒９，９ａとの間に磁気回路ｚを形成する。
【００１３】
図１，３に示すように、本発明は制動ドラム１５の開放端部ないし左端部に断面Ｌ字形の良伝導体からなる環状体４１，４２を、基端部ないし右端部に良伝導体からなる環状体４３，４４をそれぞれ結合したものである。制動ドラム１５に対する環状体４１〜４４の結合の方法は、溶接、溶着、めっきなどによる。特に、予め制動ドラム１５の端壁面と内周面１５ｂにニツケルめっきを施したうえ、めっき層の上に良伝導体からなる環状体４１〜４４をろう付けにより結合するのが好ましい。支持腕１６が結合される制動ドラム１５の端壁面については、良伝導体からなる環状体４３を支持腕１６と制動ドラム１５との間に介装すると、支持腕１６と制動ドラム１５との結合力が弱くなるので、良伝導体からなる環状体４３は支持腕１６と制動ドラム１５との結合部を除くように、周方向に分断して設けるものとし、支持腕１６を直接制動ドラム１５の端壁面に溶接により結合するのが好ましい。良伝導体からなる環状体４２，４４の内端縁は、強磁性板３１の端縁と同じ位置か、強磁性板３１の端縁よりも外方、すなわち端壁面の方へ偏倚させる。
【００１４】
図３，４に示すように、制動ドラム１５の内周面１５ｂに結合される良伝導体からなる環状体４２の方が、端壁面５５に結合される良伝導体からなる環状体４１よりも放熱性が劣るので、内周面１５ｂの良伝導体からなる環状体４２の肉厚t2を、端壁面５５の環状体４１の肉厚t1よりも厚くして熱容量を大きくし、渦電流の密度を小さくして温度上昇を抑える。
【００１５】
良伝導体からなる環状体４２の冷却性を高めるために、多数の軸方向の溝４５を環状体４２に周方向に間隔を存して設ける。溝４５の深さは、制動ドラム１５の内周面１５ｂから端壁面５５へ至るにつれて次第に深くなるように構成する。制動ドラム１５の基端部の環状体４３，４４についても同様に構成するのが好ましい。図５に示すように、溝４５はテーパ状とする代りに、深さが軸方向にほぼ一定のものであつてもよい。
【００１６】
図６，７に示す変更実施例は、良伝導体からなる環状体４２にはテーパ状の溝４５を、良伝導体からなる環状体４１には径方向の比較的浅い溝４６を互いに連続して設けたものである。良伝導体からなる環状体４１，４２に多数の溝４６，４５を周方向に間隔を存して設けたことにより、良伝導体からなる環状体４１，４２の表面積が広くなるばかりでなく、溝４６，４５のない部分が羽根車として働き、外気を制動ドラム１５の内周面１５ｂへ導き、制動ドラム１５の端部の温度上昇、特に環状体４１，４２の温度上昇を抑える。制動ドラム１５の両端部の温度上昇が抑えられるので、制動ドラム１５の両端部の渦電流が増加しても、良伝導体からなる環状体４１〜４４が制動ドラム１５から剥離することがなく、渦電流の増加分だけ制動能力が向上される。
【００１７】
図８に示すように、溝４５，４６は制動ドラム１５の径方向でなく、径方向に対して傾斜させれば、外気が溝４６，４５に沿つて径内方へ吸い寄せられやすくなり、制動ドラム１５の内周面１５ｂを効果的に冷却する。
【００１８】
上述の実施例では、案内筒６の内空部２０に回動可能の磁石支持筒９と不動の磁石支持筒９ａを収容し、磁石８，８ａが制動ドラム１５と磁石支持筒９，９ａとの間に磁気回路ｚを形成する制動位置と、磁石８，８ａが強磁性板３１と磁石支持筒９，９ａとの間に短絡的磁気回路ｗを形成する非制動位置とに切り換わる形式の渦電流減速装置について説明したが、本発明はこれに限定されるものではなく、図９に示すような渦電流減速装置にも適用できる。
【００１９】
図９に示す実施例では、案内筒６の右半部が制動ドラム１５の内部へ臨み、案内筒６の左半部が制動ドラム１５の外部へ突出される。案内筒６は磁性体からなる外筒部６ａと端壁６ｃと内筒部６ｂを有する断面Ｃ字形の筒体に、端壁６ｄをボルト１２により結合し、さらに薄板から成形される外筒部１４の左端部に形成した円錐部を、外筒部６ａの円錐面３０に重ね合せ、外筒部１４の右端部を径内方へ折り曲げたうえ端壁６ｄにボルト１２により結合して、断面長方形の内空部２０を構成する。案内筒６の端壁６ｃには、シリンダ２にピストン４を嵌挿して端室３と端室５を区画したアクチユエータＡが結合され、ピストン４から内空部２０へ突出するロツド７が磁石支持筒９に結合される。制動ドラム１５から突出する左半部の外筒部６ａは厚肉の磁性体から構成する。案内筒６の右半部つまり制動ドラム１５の内周面１５ｂに対向する外筒部１４は、非磁性体からなる薄板から構成するか、さらには例えば強磁性体のステンレス鋼の薄板から構成し、外筒部１４の磁石８の外面に対向しない部分だけを、高温状態から急冷することにより非磁性オーステナイト相にする。
【００２０】
本実施例でも図１に示すものと同様に、制動ドラム１５の両端壁面に良伝導体からなる環状体４１，４３が、内周面１５ｂに環状体４１，４３よりも厚肉の良伝導体からなる環状体４２，４４がそれぞれ結合される。良伝導体からなる環状体４２，４４の内端縁は、磁石８の両端縁よりも外方に配置され、磁石８の外面と重ならないように構成する。制動ドラム１５の外部に突出する外筒部６ａの肉厚を厚くする関係上、外筒部６ａの端部には円錐面３０が形成され、円錐面３０に対応して制動ドラム１５の開放端部にも円錐面に形成され、該円錐面に良伝導体からなる環状体４１が結合される。
非制動時、アクチユエータＡにより磁石支持筒９を制動ドラム１５から引き出すと、各磁石８は案内筒６の外筒部６ａに対向して短絡的磁気回路を形成し、制動ドラム１５には磁界を及ぼさない。制動時、磁石支持筒９が制動ドラム１５の内部へ突出されると、各磁石８からの磁界は外筒部１４を通過して制動ドラム１５へ及ぶ。回転する制動ドラム１５が磁石８からの磁界を横切る時、渦電流が制動ドラム１５に流れ、制動ドラム１５が制動トルクを発生する。
【００２１】
図９の実施例では、制動ドラム１５の内周面１５ｂに対向する外筒部１４を、非磁性体からなる薄板から構成しているが、非磁性体からなる外筒部６ａに強磁性板３１を、磁石８の外面に対向するように結合したもの（図１参照）でも、同様の作用効果を奏する。
【発明の効果】
【００２２】
本発明は上述のように、低炭素鋼などからなる制動ドラムの両端部に、銅などの良伝導体からなる環状体を結合したことにより、制動ドラムに発生する渦電流量が増加し、制動能力が向上する。特に、制動ドラムの内周面に結合される良伝導体からなる環状体を、制動ドラムの端壁面に結合される良伝導体からなる環状体よりも厚くしたことにより、良伝導体からなる環状体の熱容量が増大し、制動時のジユール熱による環状体の温度上昇が抑えられる。
【００２３】
また、良伝導体からなる環状体に多数の軸方向の溝を周方向に間隔を存して設けることにより、良伝導体からなる環状体の表面積が広くなり、また外気が内周面へ導かれるようになり、環状体の冷却性が高められるので、この点でも良伝導体からなる環状体の温度上昇が抑えられ、制動能力が高められ、また環状体の剥離や熱割れに対する耐久性が向上される。
【図面の簡単な説明】
【図１】本発明に係る渦電流減速装置の正面断面図である。
【図２】同渦電流減速装置の側面断面図である。
【図３】同渦電流減速装置の要部を拡大して示す正面断面図である。
【図４】同渦電流減速装置の側面断面図である。
【図５】本発明の変更実施例に係る渦電流減速装置の要部を示す正面断面図である。
【図６】本発明の変更実施例に係る渦電流減速装置の要部を示す正面断面図である。
【図７】図６の線７Ａ−７Ａによる側面断面図である。
【図８】本発明の変更実施例に係る渦電流減速装置の側面図である。
【図９】本発明が適用される他の形式の渦電流減速装置の正面断面図である。
【符号の説明】
Ａ：アクチユエータ２：シリンダ４：ピストン６：案内筒６ａ：外筒部６ｂ：内筒部６ｃ：端壁６ｄ：端壁８：磁石８ａ：磁石９：磁石支持筒９ａ：磁石支持筒１４：外筒部１５：制動ドラム１６：支持腕１５ｂ：内周面２０：内空部２３：制動ドラム３１：強磁性板３４：腕４１：環状体４２：環状体４３：環状体４４：環状体４５：溝４６：溝５５：端壁面BACKGROUND OF THE INVENTION
[0001]
The present invention is an eddy current reduction device for assisting a friction brake of a vehicle or the like, in particular, by connecting a good conductor such as copper to both ends of a braking drum, thereby improving the flow of eddy current and improving braking force. The present invention relates to an eddy current reduction device.
[Prior art]
[0002]
A conventional eddy current reduction device has a magnet support cylinder arranged inside a brake drum made of a conductor such as steel or low carbon steel, and is circumferentially equidistant on the outer peripheral surface of the magnet support cylinder and polar with respect to the inner peripheral surface of the brake drum. When magnets (including electromagnets) that are coupled so as to be alternately different in the circumferential direction are brought close to the inner peripheral surface of the brake drum, the rotating brake drum crosses the magnetic field from the magnet, and the braking force based on the eddy current is applied to the brake drum. Occurs. When an annular body (cylindrical body or annular plate) made of a good conductor such as copper is coupled to both ends of the braking drum via a nickel plating layer, the flow of eddy current is improved and the braking capability is improved.
[0003]
However, during braking, eddy currents are concentrated on the annular body made of a good conductor, and the temperature of the annular body made of the good conductor is hardly different from the temperature of the central portion in the axial direction of the inner peripheral surface of the braking drum. At a high temperature exceeding 600 ° C., the low carbon steel constituting the brake drum has better heat resistance than the copper constituting the annular body made of a good conductor. The operating range of the current reduction device is limited, and the braking performance of the braking drum having an annular body made of a good conductor cannot be exhibited sufficiently. In other words, when the annular body made of a good conductor is overheated, there are obstacles such as cracking of the annular body and separation from the braking drum, so there is a limit to the improvement of the braking ability. Therefore, to further improve the braking ability, it is required to suppress the temperature rise of the annular body made of a good conductor.
[Problems to be solved by the invention]
[0004]
In view of the above-described problems, an object of the present invention is to provide an eddy current reduction device that increases the heat capacity by increasing the volume of a good conductor and increases the cooling performance by outside air to suppress the temperature rise of the good conductor. There is.
[Means for Solving the Problems]
[0005]
In order to solve the above-described problems, the configuration of the present invention includes a braking drum made of a conductor coupled to a rotating shaft, and an inner space having a rectangular cross section attached to a non-rotating portion such as a vehicle body so as to face the inside of the braking drum. A guide cylinder made of a non-magnetic material, a magnet support cylinder accommodated in the inner space of the guide cylinder, and a number of rotatable magnet support cylinders coupled to the outer peripheral surface of the magnet support cylinder at equal circumferential intervals. An eddy current that has a magnet and a ferromagnetic plate that is cast on the outer cylinder portion of the guide cylinder so as to face each of the magnets, and generates a braking force based on an eddy current in the braking drum by a magnetic field from the magnet In the reduction device, an annular body made of a good conductor such as copper is continuously connected to an end portion of the inner peripheral surface of the brake drum that does not face the ferromagnetic plate and an end wall surface of the brake drum, and the brake the brake drum than the wall thickness of the annular body of the end wall of the drum The thickness of the annular body of the inner peripheral surface thick, wherein said providing a plurality of axial grooves in the annular body of the inner peripheral surface of the brake drum in the circumferential direction at equal intervals.
[0006]
Further, the structure of the present invention is a guide cylinder having a brake drum made of a conductor coupled to a rotating shaft, and an inner hollow portion having a rectangular cross section attached to a non-rotating portion such as a vehicle body so that a half portion faces the inside of the brake drum. A magnet support tube accommodated in the inner space of the guide tube so as to be movable in the axial direction, a number of magnets coupled to the outer peripheral surface of the magnet support tube at equal intervals in the circumferential direction, and an outer tube portion of the guide tube A portion made of a magnetic material that does not face the inner peripheral surface of the brake drum and a portion of the outer cylinder portion of the guide tube made of a non-magnetic material that faces the inner peripheral surface of the brake drum and faces the magnets. In an eddy current reduction device that generates a braking force based on an eddy current in the braking drum by a magnetic field from the magnet, the ferromagnetic plate does not face the ferromagnetic plate on the inner peripheral surface of the braking drum Copper continuously from the end and the end wall of the brake drum How good consisting conductor bind annular body, and increasing the thickness of the annular body of the inner peripheral surface of the brake drum than the wall thickness of the annular body of the end wall of the brake drum, the inner peripheral surface of the brake drum A large number of axial grooves are provided in the annular body at equal intervals in the circumferential direction .
DETAILED DESCRIPTION OF THE INVENTION
[0007]
In the present invention, an L-shaped annular body made of a good conductor such as copper is coupled to both end portions of the inner peripheral surface of the brake drum and both end wall surfaces of the brake drum, and particularly to an inner peripheral surface having poor heat dissipation. By making the thickness of the annular body thicker than that of the annular body coupled to the end wall surface, the density of the eddy current is reduced, and the temperature rise of the annular body due to the Diule heat is suppressed. In addition, in order to enhance the heat dissipation of the annular body coupled to the inner peripheral surface of the brake drum, a large number of axial grooves are provided in the annular body at intervals in the circumferential direction. When the brake drum rotates, the annular body acts as an impeller, and guides outside air to the annular body to cool it.
【Example】
[0008]
FIG. 1 is a front sectional view of an eddy current reduction device according to the present invention, and FIG. 2 is a side sectional view of the eddy current reduction device. The eddy current reduction device includes, for example, a brake drum 15 made of a conductor such as steel coupled to an output rotation shaft 21 of a vehicle transmission, a guide cylinder 6 made of a non-magnetic material disposed inside the brake drum 15, A movable magnet support tube 9 and an immobile magnet support tube 9a housed in an inner space 20 having a rectangular cross section of the guide tube 6 are provided. The brake drum 15 is overlapped with the flange portion 19a of the boss 19 together with the end wall of the brake drum 23 of the parking brake on the mounting flange 22 fitted to the spline 22a of the rotary shaft 21 and fastened by the nut 21a. Fastened with a plurality of bolts 24 and nuts. The base end of the brake drum 15 having the cooling fins 15a is coupled to a number of support arms 16 that extend radially from the boss 19. At both ends of the inner peripheral surface 15b of the brake drum 15, annular bodies 41 and 42 made of a good conductor such as copper and annular bodies 43 and 44 are coupled to spread the eddy current flow of the brake drum 15 in the axial direction. Increase braking power.
[0009]
For example, the guide tube 6 is configured by connecting an end wall 6d made of an annular plate to a tube made of a non-magnetic material having a C-shaped cross section. The guide tube 6 is fixed to a non-rotating part, for example, a gear box of a transmission by an appropriate means. A ferromagnetic plate 31 having retaining protrusions 31a is coupled to a large number of openings 32 provided at equal intervals in the circumferential direction on the outer cylinder portion 6a of the guide cylinder 6. Preferably, the ferromagnetic plate 31 is cast when the guide cylinder 6 is molded. The ferromagnetic plate 31 has a rectangular plate shape, and the plate surface is curved in an arc shape.
[0010]
A movable magnet support cylinder 9 made of a magnetic material is supported on the inner cylinder portion 6b by a sliding bearing or a roller bearing 35 so as to be able to rotate in the forward and reverse directions. The arm 34 extending in the axial direction from the magnet support cylinder 9 is connected to the rod of the actuator A through an arc-shaped slit 33 provided on the end wall 6 c of the guide cylinder 6. The magnet support cylinder 9 is coupled to the outer peripheral surface of a large number of magnets 8 facing the left half of each ferromagnetic plate 31 so that the polarities of the ferromagnetic plates 31 are alternately different in the circumferential direction. On the other hand, an immobile magnet support cylinder 9a made of a magnetic material is fixed to the inner cylinder part 6b in the inner space 20 of the guide cylinder 6, and the magnet 8 facing the right half of each ferromagnetic plate 31 on the outer peripheral surface. The same number of magnets 8a are coupled so that the polarities with respect to the ferromagnetic plates 31 are alternately different in the circumferential direction. A plurality of actuators A are coupled to the end wall 6c of the guide tube 6 at equal intervals in the circumferential direction. The actuator A is formed by fitting a piston 4 to the cylinder 2, and a rod protruding outward from the piston 4 is connected to an arm 34.
[0011]
As shown in FIG. 2, the magnet 8a of the magnet support cylinder 9a has a cylindrical surface on the inner surface and outer surface, and is made of a non-magnetic material between the step portions 26 formed at the circumferential ends of the magnets 8a. The fixing bracket 27 having a T-shaped cross section is engaged, and is fastened to the magnet support cylinder 9 a by a bolt 28.
[0012]
Next, the operation of the eddy current reduction device according to the present invention will be described. At the time of non-braking, as shown in FIG. 1, the magnet 8 of the magnet support tube 9 and the magnet 8a of the magnet support tube 9a have opposite polarities to the ferromagnetic plate 31. At this time, the magnets 8, 8 a form a short-circuit magnetic circuit w between each ferromagnetic plate 31 and the magnet support cylinders 9, 9 a and do not exert a magnetic field on the braking drum 15. At the time of braking, when the magnet support cylinder 9 is turned by the actuator A from the non-braking position to the braking position shown in FIG. 2 by the arrangement pitch of the magnets 8, the magnets 8 and 8 a aligned in the axial direction are opposed to the ferromagnetic plates 31. And the magnetic field is applied to the braking drum 15 through the ferromagnetic plate 31. When the rotating brake drum 15 crosses the magnetic field, an eddy current flows through the brake drum 15 and the brake drum 15 generates a braking torque. At this time, the magnets 8 and 8a form a magnetic circuit z between the brake drum 15 and the magnet support cylinders 9 and 9a.
[0013]
As shown in FIGS. 1 and 3, in the present invention, an annular body 41, 42 made of a good conductor having an L-shaped cross section is provided at the open end or the left end of the brake drum 15, and a good conductor is provided at the base end or the right end. The annular bodies 43 and 44 are combined. The method of joining the annular bodies 41 to 44 to the brake drum 15 is by welding, welding, plating, or the like. In particular, it is preferable that nickel plating is applied to the end wall surface and the inner peripheral surface 15b of the brake drum 15 in advance, and the annular bodies 41 to 44 made of a good conductor are bonded onto the plating layer by brazing. With respect to the end wall surface of the brake drum 15 to which the support arm 16 is coupled, when the annular body 43 made of a good conductor is interposed between the support arm 16 and the brake drum 15, the support arm 16 and the brake drum 15 are coupled. Since the force is weakened, the annular body 43 made of a good conductor is provided to be divided in the circumferential direction so as to exclude the connecting portion between the support arm 16 and the brake drum 15, and the support arm 16 is directly attached to the brake drum 15. It is preferable to join the end wall surface by welding. The inner end edges of the annular bodies 42 and 44 made of a good conductor are biased to the same position as the end edge of the ferromagnetic plate 31 or outward from the end edge of the ferromagnetic plate 31, that is, toward the end wall surface.
[0014]
As shown in FIGS. 3 and 4, the annular body 42 made of a good conductor coupled to the inner peripheral surface 15 b of the brake drum 15 is more than the annular body 41 made of a good conductor coupled to the end wall surface 55. Since the heat dissipation is inferior, the thickness t2 of the annular body 42 made of a good conductor on the inner peripheral surface 15b is made thicker than the thickness t1 of the annular body 41 of the end wall surface 55 to increase the heat capacity, and the density of eddy currents. Reduce the temperature rise.
[0015]
In order to improve the cooling performance of the annular body 42 made of a good conductor, a large number of axial grooves 45 are provided in the annular body 42 at intervals in the circumferential direction. The depth of the groove 45 is configured so as to gradually become deeper from the inner peripheral surface 15 b of the braking drum 15 to the end wall surface 55. The annular bodies 43 and 44 at the base end of the brake drum 15 are preferably configured in the same manner. As shown in FIG. 5, the groove 45 may have a substantially constant depth in the axial direction instead of being tapered.
[0016]
In the modified embodiment shown in FIGS. 6 and 7, a tapered groove 45 is formed in the annular body 42 made of a good conductor, and a relatively shallow groove 46 in the radial direction is made continuous in the annular body 41 made of a good conductor. Is provided. By providing a large number of grooves 46 and 45 in the circumferential direction at intervals in the annular bodies 41 and 42 made of a good conductor, not only the surface area of the annular bodies 41 and 42 made of a good conductor is increased, The portion without the grooves 46 and 45 functions as an impeller, and guides the outside air to the inner peripheral surface 15b of the brake drum 15 to suppress the temperature rise at the end of the brake drum 15, particularly the temperature rise of the annular bodies 41 and 42. Since the temperature rise at both ends of the brake drum 15 is suppressed, even if the eddy current at both ends of the brake drum 15 increases, the annular bodies 41 to 44 made of a good conductor do not peel from the brake drum 15, The braking ability is improved by the increase in eddy current.
[0017]
As shown in FIG. 8, if the grooves 45 and 46 are inclined with respect to the radial direction instead of the radial direction of the braking drum 15, the outside air is likely to be sucked radially inward along the grooves 46 and 45. The inner peripheral surface 15b of the drum 15 is effectively cooled.
[0018]
In the above-described embodiment, the rotatable magnet support tube 9 and the stationary magnet support tube 9a are accommodated in the inner space 20 of the guide tube 6, and the magnets 8 and 8a are connected to the brake drum 15 and the magnet support tubes 9 and 9a. Between the braking position in which the magnetic circuit z is formed and the non-braking position in which the magnets 8 and 8a form the short-circuited magnetic circuit w between the ferromagnetic plate 31 and the magnet support cylinders 9 and 9a. Although the eddy current reduction device has been described, the present invention is not limited to this, and can also be applied to an eddy current reduction device as shown in FIG.
[0019]
In the embodiment shown in FIG. 9, the right half of the guide cylinder 6 faces the inside of the brake drum 15, and the left half of the guide cylinder 6 protrudes to the outside of the brake drum 15. The guide tube 6 has an outer tube portion 6a formed of a thin plate by coupling the end wall 6d with a bolt 12 to a C-shaped tube body having an outer tube portion 6a made of a magnetic material, an end wall 6c, and an inner tube portion 6b. 14 is overlapped with the conical surface 30 of the outer cylinder part 6a, the right end part of the outer cylinder part 14 is bent radially inward, and is joined to the end wall 6d by the bolt 12, A rectangular inner space 20 is formed. An actuator A is inserted into the end wall 6c of the guide tube 6 to insert the piston 4 into the cylinder 2 to partition the end chamber 3 and the end chamber 5, and a rod 7 protruding from the piston 4 to the inner space 20 supports the magnet. Coupled to the tube 9. The outer half 6a of the left half projecting from the brake drum 15 is made of a thick magnetic material. The right half of the guide cylinder 6, that is, the outer cylinder part 14 facing the inner peripheral surface 15b of the brake drum 15, is made of a thin plate made of a non-magnetic material, or made of, for example, a ferromagnetic stainless steel thin plate. Only the portion of the outer cylinder portion 14 that does not face the outer surface of the magnet 8 is rapidly cooled from a high temperature state to make a nonmagnetic austenite phase.
[0020]
In the present embodiment as well, as shown in FIG. 1, the annular bodies 41 and 43 made of a good conductor are provided on both end wall surfaces of the brake drum 15, and the good conductor is thicker than the annular bodies 41 and 43 on the inner peripheral surface 15b. The annular bodies 42 and 44 made of are joined together. The inner end edges of the annular bodies 42, 44 made of a good conductor are arranged outside the both end edges of the magnet 8 and are configured not to overlap the outer surface of the magnet 8. A conical surface 30 is formed at the end of the outer cylindrical portion 6 a in order to increase the thickness of the outer cylindrical portion 6 a that protrudes outside the braking drum 15, and the open end of the braking drum 15 corresponds to the conical surface 30. A circular surface 41 made of a good conductor is coupled to the conical surface.
When the magnet support cylinder 9 is pulled out from the brake drum 15 by the actuator A during non-braking, each magnet 8 forms a short circuit magnetic circuit facing the outer cylinder portion 6a of the guide cylinder 6, and a magnetic field is applied to the brake drum 15. Does not reach. At the time of braking, when the magnet support cylinder 9 protrudes into the brake drum 15, the magnetic field from each magnet 8 passes through the outer cylinder portion 14 and reaches the brake drum 15. When the rotating brake drum 15 crosses the magnetic field from the magnet 8, an eddy current flows through the brake drum 15 and the brake drum 15 generates a braking torque.
[0021]
In the embodiment of FIG. 9, the outer cylinder portion 14 facing the inner peripheral surface 15b of the brake drum 15 is made of a thin plate made of a nonmagnetic material, but the ferromagnetic plate is attached to the outer cylinder portion 6a made of a nonmagnetic material. The same operation and effect can be achieved by connecting 31 to the outer surface of the magnet 8 (see FIG. 1).
【The invention's effect】
[0022]
As described above, according to the present invention, since the annular body made of a good conductor such as copper is coupled to both ends of the brake drum made of low carbon steel or the like, the amount of eddy current generated in the brake drum increases, Ability improves. In particular, the annular body made of a good conductor coupled to the inner peripheral surface of the brake drum is made thicker than the annular body made of a good conductor joined to the end wall surface of the brake drum, so that the annular body made of a good conductor is formed. The heat capacity of the body is increased, and the temperature rise of the annular body due to Jule heat during braking is suppressed.
[0023]
Also, by providing a large number of axial grooves in the annular body made of a good conductor with a space in the circumferential direction, the surface area of the annular body made of a good conductor is increased, and outside air is guided to the inner peripheral surface. Since the cooling performance of the annular body is improved, the temperature rise of the annular body made of a good conductor can be suppressed in this respect, the braking ability is increased, and the durability against peeling and thermal cracking of the annular body is improved. Be improved.
[Brief description of the drawings]
FIG. 1 is a front sectional view of an eddy current reduction device according to the present invention.
FIG. 2 is a side sectional view of the eddy current reduction device.
FIG. 3 is an enlarged front sectional view showing a main part of the eddy current reduction device.
FIG. 4 is a side sectional view of the eddy current reduction device.
FIG. 5 is a front sectional view showing a main part of an eddy current reduction device according to a modified embodiment of the present invention.
FIG. 6 is a front sectional view showing a main part of an eddy current reduction device according to a modified embodiment of the present invention.
7 is a side cross-sectional view taken along line 7A-7A in FIG. 6;
FIG. 8 is a side view of an eddy current reduction device according to a modified embodiment of the present invention.
FIG. 9 is a front sectional view of another type of eddy current reduction device to which the present invention is applied.
[Explanation of symbols]
A: Actuator 2: Cylinder 4: Piston 6: Guide tube 6a: Outer tube portion 6b: Inner tube portion 6c: End wall 6d: End wall 8: Magnet 8a: Magnet 9: Magnet support tube 9a: Magnet support tube 14: Outer Tube portion 15: Braking drum 16: Support arm 15b: Inner peripheral surface 20: Inner space portion 23: Braking drum 31: Ferromagnetic plate 34: Arm 41: Ring body 42: Ring body 43: Ring body 44: Ring body 45: Groove 46: Groove 55: End wall surface

Claims

A brake drum made of a conductor coupled to a rotating shaft, a guide cylinder made of a non-magnetic material having an inner space with a rectangular cross section attached to a non-rotating portion such as a vehicle body so as to face the inside of the brake drum, and the guide cylinder At least one of the magnet support cylinders accommodated in the inner space, a number of magnets coupled to the outer peripheral surface of the magnet support cylinders at equal intervals in the circumferential direction, and An eddy current reduction device having a ferromagnetic plate cast opposite to a magnet, and generating a braking force based on an eddy current in the braking drum by a magnetic field from the magnet, the inner peripheral surface of the braking drum An annular body made of a good conductor such as copper is continuously connected to an end portion not facing the ferromagnetic plate and an end wall surface of the braking drum, and the thickness of the annular body on the end wall surface of the braking drum is larger than that of the annular body. Increasing the thickness of the annular body on the inner peripheral surface of the brake drum, Eddy current reduction apparatus characterized by a groove of a number of axially arranged circumferentially at equal intervals on the annular body of the inner peripheral surface of the ram.

A brake drum made of a conductor coupled to a rotating shaft, a guide cylinder having an inner space with a rectangular cross section attached to a non-rotating part such as a vehicle body so that a half part faces the inside of the brake drum, A magnet support cylinder accommodated in the hollow portion so as to be movable in the axial direction, a number of magnets coupled to the outer peripheral surface of the magnet support cylinder at equal intervals in the circumferential direction, and the inner peripheral surface of the brake drum of the outer cylinder portion of the guide cylinder A portion made of a magnetic material that is not opposed to the outer peripheral portion of the guide tube made of a non-magnetic material, and a ferromagnetic plate cast in a portion facing the inner peripheral surface of the brake drum and facing each magnet. And an eddy current reduction device for generating a braking force based on an eddy current in the braking drum by a magnetic field from the magnet, and an end portion of the inner peripheral surface of the braking drum that does not face the ferromagnetic plate and the braking drum Continuing from the end wall, it is made of a good conductor such as copper. Bind annular body, the than the thickness of the annular body of the end wall of the brake drum to increase the thickness of the annular body of the inner peripheral surface of the brake drum, a number of the annular body of the inner peripheral surface of the brake drum An eddy current reduction device characterized in that axial grooves are provided at equal intervals in the circumferential direction .