JP3719338B2

JP3719338B2 - Eddy current reducer

Info

Publication number: JP3719338B2
Application number: JP31705398A
Authority: JP
Inventors: 徹桑原
Original assignee: Isuzu Motors Ltd
Current assignee: Isuzu Motors Ltd
Priority date: 1998-11-09
Filing date: 1998-11-09
Publication date: 2005-11-24
Anticipated expiration: 2018-11-09
Also published as: JP2000152601A

Description

【０００１】
【発明の属する技術分野】
本発明は大形車両などの摩擦ブレーキの負担を軽減する渦電流減速装置、特に永久磁石（以下、これを単に磁石という）の磁束が制動ドラムへ有効に働くようにした渦電流減速装置に関するものである。
【０００２】
【従来の技術】
従来の渦電流減速装置における案内筒に配される強磁性板の側面断面の形状は長方形のものであり、外面と内面の面積がほぼ同じであり、磁石からの磁束は強磁性板で絞られないで制動ドラムへ達する。また、案内筒の内部に不動の磁石支持筒と可動の磁石支持筒を軸方向に並べた渦電流減速装置では、共通の強磁性板に対し互いに異なる極性の磁石が対向する非制動時の磁石からの洩れ磁束による引きずりトルクを抑えるために強磁性板を厚くしなければならない。同様に、特開平10-127039 号公報に開示されるように、強磁性板の正面断面の形状を台形とした場合にも、強磁性板を厚くしなければならなかつた。
【０００３】
【発明が解決しようとする課題】
本発明の課題は制動ドラムの特に中速回転域で磁石から制動ドラムへ及ぶ磁束を集中させて磁束密度を大きくし、制動ドラムに発生する渦電流を多くし、制動力を増大する渦電流減速装置を提供することにある。
【０００４】
【課題を解決するための手段】
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制動ドラムの内部に非磁性体からなる断面長方形の内空部を有する案内筒を配設し、該案内筒の外筒部に周方向等間隔に多数の強磁性板を結合し、前記案内筒の内空部に回動可能または軸方向移動可能に支持した少くとも１つの磁石支持筒の外周面に、前記各強磁性板に対向しかつ強磁性板に対する極性が周方向に交互に異なるように磁石を結合してなる渦電流減速装置において、前記強磁性板の中央部から磁石に対向する内面に至る部分の板厚を均一にし、前記強磁性板の前面について板厚の中央部から制動ドラムに対向する外面に至る部分を制動ドラムの回転方向後方へ傾斜させ、前記強磁性板の後面について板厚の中央部から制動ドラムに対向する外面に至る部分を制動ドラムの回転方向前方へ傾斜させて、これにより前記強磁性板の外面の面積を内面の面積よりも狭くし、前記強磁性板の板厚の中央部に強磁性板の周囲を囲む抜止め突条を設けたことを特徴とする。
【０００５】
【発明の実施の形態】
渦電流減速装置は仕様ないし寸法が同じならば、制動ドラムの回転数が大きく、制動ドラムの内径が大きいほど大きな制動力が得られる。しかし、特に中型貨物車両の場合に、変速機の後部へ渦電流減速装置を配設するとなれば制動ドラムの内径は制限され、高速道路を走行する機会が少なければ制動ドラムの回転数も制限される。中型貨物車両の通常の走行で、つまり制動ドラムの中速回転域でより大きな制動力を発生することが望まれる。
【０００６】
本発明では制動ドラムの中速回転域では、制動時の磁気回路の歪みが少いことから、磁石から制動ドラムへ到達する磁束が強磁性板の中央部で集束するようにするために、強磁性板の側面断面の形状を６角形に似たものにし、強磁性板を厚くしないでも、制動ドラムへの磁束の絞込み効果を発揮させ、鋳込み前の強磁性板の機械加工を削減する。
【０００７】
【実施例】
図１は本発明による渦電流減速装置の正面断面図、図２は同側面断面図である。本発明による渦電流減速装置は、例えば車両用変速機の出力回転軸１に結合される導体からなる制動ドラム７と、制動ドラム７の内部に配設される非磁性体からなる案内筒１０と、案内筒１０の断面長方形の内空部に収容した可動の磁石支持筒１４とを備えている。制動ドラム７はボス５のフランジ部５ａを、駐車ブレーキの制動ドラム３の端壁部と一緒に、回転軸１にスプライン嵌合した取付フランジ２に重ね合され、かつ複数のボルト４とナツトにより締結される。ボス５から放射状に延びる多数のスポーク６に、冷却フイン８を備えた制動ドラム７の基端が結合される。
【０００８】
断面箱形をなす案内筒１０は例えば断面Ｃ字形の筒体に、環状板からなる端壁１１を結合して構成される。案内筒１０は適当な手段により例えば変速機の歯車箱に固定される。案内筒１０の外筒部１０ａは周方向等間隔に設けた多数の開口２５に、長方形の強磁性板（ポールピース）１５を埋設して結合される。好ましくは、強磁性板１５は案内筒１０の成形時鋳込まれる。厳密には、案内筒１０は強度の点からみれば、強磁性板１５を結合する外筒部１０ａだけを非磁性体とすれば足りる。
【０００９】
磁性体からなる磁石支持筒１４は、案内筒１０の内空部にあつて、滑り軸受またはコロ軸受１２により正逆回動可能に内筒部１０ｂに支持される。磁石支持筒１４から軸方向へ延びる腕１６は、案内筒１０の左端壁に設けた円弧状のスリツト１８ａを経て、流体圧アクチユエータ２０のロツドに連結される。磁石支持筒１４は外周面に各強磁性板１５に対向する磁石２４を、強磁性板１５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１０の左端壁に結合されるアクチユエータ２０は、シリンダ１８にピストン１７を嵌装してなり、ピストン１７から外部へ突出するロツドは腕１６と連結される。
【００１０】
本発明では磁石２４から制動ドラム７へ向う（この逆も同じ）磁束密度が、強磁性板１５の中央部（制動ドラム７の回転方向中央部分）で最大になるように、従来の直方体に似たものとは異なり、制動ドラム７の内周面に対向する強磁性板１５の外面５０ａの面積が、磁石２４に対向する内面５０ｂの面積よりも狭く構成される。強磁性板１５の両側面５０ｃは互いに平行で回転軸（制動ドラム７の回転軸線）に対して垂直な平面に形成される。
【００１１】
図４に示すように、強磁性板１５は制動ドラム７の内周面に対向する面積の狭い外面５０ａと、磁石２４の外面を覆う面積の広い内面５０ｂと、前面１５ａと、後面１５ｂと、互いに平行な両側面５０ｃとを備えている。前面１５ａは内面５０ｂと外面５０ａの間の途中から外面５０ａに向つて制動ドラム７の回転方向（矢印ｙ）後方へ傾斜される。同様に後面１５ｂは内面５０ｂと外面５０ａの間の途中から外面５０ａに向つて制動ドラム７の回転方向前方へ傾斜される。
【００１２】
強磁性板１５には全周囲を囲む抜止め突条１５ｃが予め一体に形成され、案内筒１０の外筒部１０ａに鋳込まれる。この抜止め突条１５ｃは強磁性板１５を鍛造にて製作する際に生じるパーテイングラインを使用してもよい。案内筒１０の鋳造後、案内筒１０の外筒部１０ａの外周面と内周面は、機械加工により円筒面に仕上げられる。図４に示すように、抜止め突条１５ｃは強磁性板１５の側面５０ｃで傾けないで、周方向に延びるように構成してもよい。
【００１３】
図５に示す実施例では、案内筒１０の外筒部１０ａの制動ドラム７と対向する部分は薄いステンレス鋼板から構成される。強磁性板１５は薄いステンレス鋼板からなる外筒部１０ａに設けた開口２５へ嵌合され、かつ溶接などにより結合される。好ましくは、外筒部１０ａには軸方向に延びる溝形の補強リブ３１が成形される。補強リブ３１は外筒部１０ａから径外方へ突出するものでもよい。
【００１４】
本実施例では、強磁性板１５は内面５０ｂが外筒部１０ａの内周面と一致するように結合されているが、強磁性板１５の外面５０ａが外筒部１０ａの外周面と一致するように結合してもよい。さらに、図５に示すように、強磁性板１５は外面５０ａと内面５０ｂとの間の中間部分を、外筒部１０ａの開口２５へ嵌合し、かつ溶接により結合するようにしてもよい。
【００１５】
以上の実施例において、非制動時、図２に示すように、磁石支持筒１４の周方向に並ぶ２つの磁石２４は、共通の強磁性板１５に全面的に対向する極性が互いに逆になつている。この時、２つの磁石２４は各強磁性板１５と磁石支持筒１４との間に、短絡的磁気回路ｗを形成し、制動ドラム７に磁界を及ぼさない。制動時、図３に示すように、周方向に並ぶ２つの磁石２４は各強磁性板１５に対向する極性が同じになり、強磁性板１５を経て制動ドラム７に磁界を及ぼす。この時、各磁石２４は制動ドラム７と磁石支持筒１４との間に、磁気回路ｚを形成する。回転する制動ドラム７が磁界を横切る時、制動ドラム７に渦電流が流れ、制動ドラム７は制動トルクを受ける。
【００１６】
以上のように、本発明では案内筒１０の外筒部１０ａに結合された強磁性板１５が、側面断面の形状を６角形に似たものにされ、外面５０ａの面積を内面５０ｂの面積よりも狭くされているので、磁石２４から制動ドラム７へ到達する磁束が絞られ、制動ドラム７に強い磁界が及ぶ。したがつて、制動ドラム７に流れる渦電流が増加し、制動力が増大される。
【００１７】
本発明は図１〜３に示すような、回転軸１に結合した制動ドラム７の内部に、非磁性体からなりかつ断面長方形の内空部を有する案内筒１０を配設し、案内筒１０の外筒部１０ａに周方向等間隔に多数の強磁性板１５を配設し、案内筒１０の内空部に正逆回動可能に配設した磁性体からなる磁石支持筒１４の外周面に、各強磁性板１５に２つずつ対向しかつ強磁性板１５に対する極性が周方向に２つごとに異なるように磁石２４を結合し、異極性の磁石２４が各強磁性板１５に全面的に対向する非制動位置と、同極性の磁石２４が各強磁性板１５に全面的に対向する制動位置とに、磁石支持筒１４を流体圧アクチユエータ２０により正逆回動して切り換えるようにした渦電流減速装置に限定されるものではなく、他の形式の渦電流減速装置にも適用できる。
【００１８】
図６，７に示す実施例では、回転軸１に結合した制動ドラム７の内部に、非磁性体からなりかつ断面長方形の内空部を有する案内筒１０を配設し、案内筒１０の外筒部１０ａに周方向等間隔に多数の強磁性板１５を配設し、案内筒１０の内空部に正逆回動可能に配設した磁性体からなる磁石支持筒１４の外周面に、各強磁性板１５に対向する極性が周方向に交互に異なるように磁石２４を結合し、周方向に隣接する２つの磁石２４が各強磁性板１５に部分的に対向する非制動位置（図６に示す状態）と、１つの磁石２４が各強磁性板１５に全面的に対向する制動位置（図７に示す状態）とに、磁石支持筒１４を流体圧アクチユエータ２０（図１を参照）により正逆回動して切り換えるようにし、図４に示したように、強磁性板１５の前面１５ａを制動ドラム７の回転方向後方へ傾斜させ、強磁性板１５の後面１５ｂを制動ドラム７の回転方向前方へ傾斜させて、外面５０ａの面積を内面５０ｂの面積よりも狭くする。
【００１９】
図８に示す実施例では、回転軸１に結合した制動ドラム７の内部に、非磁性体からなりかつ断面長方形の内空部を有する案内筒１０を配設し、案内筒１０の外筒部１０ａに周方向等間隔に多数の強磁性板１５を配設し、案内筒１０の内空部に収容した磁性体からなる可動の磁石支持筒１４と不動の磁石支持筒１４Ａの外面に、各強磁性板１５に対向しかつ強磁性板１５に対する極性が周方向に交互に異なるように磁石２４，２４Ａをそれぞれ結合し、異極性の磁石２４，２４Ａが各強磁性板１５に全面的に対向する非制動位置（図８に示す状態）と、同極性の磁石２４，２４Ａが各強磁性板１５に全面的に対向する制動位置（図７に示す状態と同じ）とに、可動の磁石支持筒１４を流体圧アクチユエータ２０により、磁石２４の半配列ピツチだけ正逆回動して切り換えるようにし、図４に示したように、強磁性板１５の前面を制動ドラム７の回転方向後方へ傾斜させ、強磁性板１５の後面を制動ドラム７の回転方向前方へ傾斜させて、外面５０ａの面積を内面５０ｂの面積よりも狭くする。
【００２０】
図９に示す実施例では、回転軸１に結合した制動ドラム７の内部に、非磁性体からなりかつ断面長方形の内空部を有する案内筒１０を配設し、案内筒１０の外筒部１０ａに周方向等間隔に多数の強磁性板１５を配設し、案内筒１０の内空部に軸方向移動可能に支持した磁性体からなる磁石支持筒１４の外面に、各強磁性板１５に対する極性が周方向に交互に異なるように磁石２４を結合し、磁石支持筒１４が制動ドラム７の内部へ突出して各磁石２４が強磁性板１５に全面的に対向する図示の制動位置（図７に示す状態と同じ）と、磁石支持筒１４が制動ドラム７から軸方向に引退して各磁石２４が強磁性板１５に対向しない非制動位置とに、磁石支持筒１４を流体圧アクチユエータ２０により軸方向に往復移動して切り換えるようにし、図４に示したように、強磁性板１５の前面を制動ドラム７の回転方向後方へ傾斜させ、強磁性板１５の後面を制動ドラム７の回転方向前方へ傾斜させて、外面５０ａの面積を内面５０ｂの面積よりも狭くする。
【００２１】
【発明の効果】
本発明は上述のように、回転軸に結合した制動ドラムの内部に非磁性体からなる断面長方形の内空部を有する案内筒を配設し、該案内筒の外筒部に周方向等間隔に多数の強磁性板を結合し、前記案内筒の内空部に回動可能または軸方向移動可能に支持した少くとも１つの磁石支持筒の外周面に、前記各強磁性板に対向しかつ強磁性板に対する極性が周方向に交互に異なるように磁石を結合してなる渦電流減速装置において、前記強磁性板の中央部から磁石に対向する内面に至る部分の板厚を均一にし、前記強磁性板の前面について板厚の中央部から制動ドラムに対向する外面に至る部分を制動ドラムの回転方向後方へ傾斜させ、前記強磁性板の後面について板厚の中央部から制動ドラムに対向する外面に至る部分を制動ドラムの回転方向前方へ傾斜させて、これにより前記強磁性板の外面の面積を内面の面積よりも狭くし、前記強磁性板の板厚の中央部に強磁性板の周囲を囲む抜止め突条を設けたので、磁石から制動ドラムへ到達する磁束が強磁性板で絞られ、制動ドラムに流れる渦電流が増加し、制動力が増大される。
【図面の簡単な説明】
【図１】本発明が適用され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非制動時の側面断面図である。
【図３】同渦電流減速装置の制動時の側面断面図である。
【図４】他の強磁性板の側面図である。
【図５】本発明が適用される第２の渦電流減速装置における、薄いステンレス鋼板からなる案内筒の外筒部に対する強磁性板の結合構造を示す斜視図である。
【図６】本発明が適用される第３の渦電流減速装置の非制動時の側面断面図である。
【図７】同渦電流減速装置の制動時の側面断面図である。
【図８】本発明が適用される第４の渦電流減速装置の非制動時の正面断面図である。
【図９】本発明が適用される第５の渦電流減速装置の制動時の正面断面図である。
【符号の説明】
３：制動ドラム６：スポーク７：制動ドラム８：冷却フイン１０：案内筒１０ａ：外筒部１０ｂ：内筒部１４：磁石支持筒１４Ａ：磁石支持筒１５：強磁性板
１５ａ：前面１５ｂ：後面１５ｃ：抜止め突条２０：アクチユエータ２４：磁石２４Ａ：磁石２５：開口５０ａ：外面５０ｂ：内面５０ｃ：側面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an eddy current reduction device for reducing the burden of a friction brake on a large vehicle or the like, and more particularly to an eddy current reduction device in which a magnetic flux of a permanent magnet (hereinafter simply referred to as a magnet) works effectively on a braking drum. It is.
[0002]
[Prior art]
The shape of the side cross section of the ferromagnetic plate arranged in the guide cylinder in the conventional eddy current reduction device is rectangular, the area of the outer surface and the inner surface is almost the same, and the magnetic flux from the magnet is reduced by the ferromagnetic plate. Without reaching the braking drum. Further, in an eddy current reduction device in which a stationary magnet support tube and a movable magnet support tube are arranged in the axial direction inside the guide tube, a non-braking magnet in which magnets of different polarities are opposed to a common ferromagnetic plate In order to suppress drag torque due to leakage magnetic flux from the magnetic field, the ferromagnetic plate must be thickened. Similarly, as disclosed in JP-A-10-127039, even when the shape of the front cross section of the ferromagnetic plate is a trapezoid, the ferromagnetic plate has to be thickened.
[0003]
[Problems to be solved by the invention]
The object of the present invention is to reduce the eddy current deceleration that increases the magnetic flux density by increasing the magnetic flux density by concentrating the magnetic flux from the magnet to the braking drum, particularly in the middle speed rotation range of the braking drum, and increasing the eddy current generated in the braking drum. To provide an apparatus.
[0004]
[Means for Solving the Problems]
In order to solve the above-described problems, the configuration of the present invention is such that a guide cylinder having a rectangular inner section made of a nonmagnetic material is disposed inside a brake drum coupled to a rotating shaft, and an outer cylinder portion of the guide cylinder A large number of ferromagnetic plates are coupled at equal intervals in the circumferential direction, and each of the ferromagnetic plates is supported on the outer peripheral surface of at least one magnet support cylinder that is rotatably or axially supported in the inner space of the guide cylinder. In the eddy current moderation device, wherein the magnet is coupled so that the polarity with respect to the ferromagnetic plate is alternately different in the circumferential direction, the plate thickness of the portion from the central portion of the ferromagnetic plate to the inner surface facing the magnet The front surface of the ferromagnetic plate is inclined from the central portion of the plate thickness to the outer surface facing the brake drum toward the rear in the rotational direction of the brake drum, and the rear surface of the ferromagnetic plate is inclined from the central portion of the plate thickness. the portion extending outside surface facing the brake drum braking de The outer surface area of the ferromagnetic plate is made narrower than the inner surface area so that the outer surface of the ferromagnetic plate is in the center of the thickness of the ferromagnetic plate. It is characterized by the provision of a strip .
[0005]
DETAILED DESCRIPTION OF THE INVENTION
If the specifications or dimensions of the eddy current reduction device are the same, the braking force increases as the number of revolutions of the braking drum increases and the inner diameter of the braking drum increases. However, especially in the case of medium-sized cargo vehicles, if an eddy current reduction device is provided at the rear of the transmission, the inner diameter of the brake drum is limited, and if there are few opportunities to travel on the highway, the rotation speed of the brake drum is also limited. The It is desired to generate a larger braking force during normal traveling of the medium-sized cargo vehicle, that is, in the middle speed rotation region of the braking drum.
[0006]
In the present invention, since the distortion of the magnetic circuit at the time of braking is small in the middle speed rotation region of the braking drum, the magnetic flux reaching the braking drum from the magnet is concentrated at the central portion of the ferromagnetic plate. the shape of the cross-sectional side view of the magnetic plate to resemble a hexagonal, even without increasing the ferromagnetic plate, the effect narrowing the magnetic flux to the brake drum is exerted to reduce the machining of the front ferromagnetic plate casting .
[0007]
【Example】
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 thereof. The eddy current reduction device according to the present invention includes, for example, a brake drum 7 made of a conductor coupled to an output rotation shaft 1 of a vehicle transmission, and a guide cylinder 10 made of a nonmagnetic material disposed inside the brake drum 7. , And a movable magnet support cylinder 14 housed in an inner space having a rectangular cross section of the guide cylinder 10. The brake drum 7 has the flange portion 5a of the boss 5 and the end wall portion of the brake drum 3 of the parking brake superimposed on the mounting flange 2 that is spline-fitted to the rotary shaft 1, and a plurality of bolts 4 and nuts. It is concluded. The base end of the brake drum 7 having the cooling fins 8 is coupled to a large number of spokes 6 extending radially from the boss 5.
[0008]
The guide cylinder 10 having a cross-sectional box shape is configured, for example, by connecting an end wall 11 made of an annular plate to a cylindrical body having a C-shaped cross section. The guide tube 10 is fixed to a gear box of a transmission, for example, by appropriate means. The outer cylinder portion 10a of the guide cylinder 10 is coupled by embedding a rectangular ferromagnetic plate (pole piece) 15 in a large number of openings 25 provided at equal intervals in the circumferential direction. Preferably, the ferromagnetic plate 15 is cast when the guide tube 10 is formed. Strictly speaking, from the viewpoint of strength, the guide tube 10 need only be a non-magnetic material for the outer tube portion 10a to which the ferromagnetic plate 15 is coupled.
[0009]
The magnet support cylinder 14 made of a magnetic material is supported by the inner cylinder portion 10b so that it can rotate forward and backward by a sliding bearing or roller bearing 12 in the inner space of the guide cylinder 10. The arm 16 extending in the axial direction from the magnet support cylinder 14 is connected to the rod of the fluid pressure actuator 20 through an arc-shaped slit 18 a provided on the left end wall of the guide cylinder 10. The magnet support cylinder 14 is coupled to the outer peripheral surface of the magnets 24 facing the ferromagnetic plates 15 so that the polarities with respect to the ferromagnetic plates 15 are alternately different in the circumferential direction. The actuator 20 coupled to the left end wall of the guide tube 10 is formed by fitting a piston 17 into the cylinder 18, and a rod protruding outward from the piston 17 is connected to the arm 16.
[0010]
In the present invention, the magnetic flux density from the magnet 24 toward the braking drum 7 (and vice versa) is similar to that of a conventional rectangular parallelepiped so that the magnetic flux density is maximized at the central portion of the ferromagnetic plate 15 (the central portion in the rotational direction of the braking drum 7). Unlike the above, the area of the outer surface 50 a of the ferromagnetic plate 15 facing the inner peripheral surface of the brake drum 7 is configured to be smaller than the area of the inner surface 50 b facing the magnet 24. Both side surfaces 50c of the ferromagnetic plate 15 are formed in a plane parallel to each other and perpendicular to the rotation axis (rotation axis of the brake drum 7).
[0011]
As shown in FIG. 4 , the ferromagnetic plate 15 includes an outer surface 50a having a small area facing the inner peripheral surface of the brake drum 7, an inner surface 50b having a large area covering the outer surface of the magnet 24, a front surface 15a, a rear surface 15b, Both side surfaces 50c parallel to each other are provided. The front surface 15a is inclined rearward in the rotational direction (arrow y) of the braking drum 7 from the middle between the inner surface 50b and the outer surface 50a toward the outer surface 50a. Similarly, the rear surface 15b is inclined forward in the rotational direction of the brake drum 7 from the middle between the inner surface 50b and the outer surface 50a toward the outer surface 50a.
[0012]
The ferromagnetic plate 15 is integrally formed with a retaining protrusion 15 c surrounding the entire periphery in advance, and is cast into the outer tube portion 10 a of the guide tube 10. The retaining protrusion 15c may use a parting line generated when the ferromagnetic plate 15 is manufactured by forging. After the casting of the guide tube 10, the outer peripheral surface and the inner peripheral surface of the outer tube portion 10a of the guide tube 10 are finished into a cylindrical surface by machining. As illustrated in FIG. 4, the retaining protrusion 15 c may be configured to extend in the circumferential direction without being inclined by the side surface 50 c of the ferromagnetic plate 15.
[0013]
In the embodiment shown in FIG. 5 , the portion of the outer tube portion 10a of the guide tube 10 that faces the brake drum 7 is made of a thin stainless steel plate. The ferromagnetic plate 15 is fitted into an opening 25 provided in the outer cylinder portion 10a made of a thin stainless steel plate, and is joined by welding or the like. Preferably, a groove-shaped reinforcing rib 31 extending in the axial direction is formed on the outer cylinder portion 10a. The reinforcing rib 31 may protrude outward from the outer cylinder portion 10a.
[0014]
In this embodiment, the ferromagnetic plate 15 is coupled to the inner surface 50b coincides with the inner peripheral surface of the outer cylindrical portion 10a, matching the outer surface 50a of the plate member 15 and the outer peripheral surface of the outer tubular portion 10a You may combine. Further, as shown in FIG. 5, the ferromagnetic plate 15 may be configured such that an intermediate portion between the outer surface 50a and the inner surface 50b is fitted into the opening 25 of the outer cylinder portion 10a and joined by welding.
[0015]
In the above embodiment, when not braked, as shown in FIG. 2, the two magnets 24 arranged in the circumferential direction of the magnet support cylinder 14 are opposite in polarity to the common ferromagnetic plate 15 as opposed to each other. ing. At this time, the two magnets 24 form a short-circuit magnetic circuit w between each ferromagnetic plate 15 and the magnet support cylinder 14, and do not exert a magnetic field on the brake drum 7. At the time of braking, as shown in FIG. 3, the two magnets 24 arranged in the circumferential direction have the same polarity facing each ferromagnetic plate 15, and exert a magnetic field on the braking drum 7 through the ferromagnetic plate 15. At this time, each magnet 24 forms a magnetic circuit z between the brake drum 7 and the magnet support cylinder 14. When the rotating brake drum 7 crosses the magnetic field, an eddy current flows through the brake drum 7 and the brake drum 7 receives a braking torque.
[0016]
As described above, in the present invention, the ferromagnetic plate 15 coupled to the outer tube portion 10a of the guide tube 10 has a side cross-sectional shape similar to a hexagon, and the area of the outer surface 50a is made larger than the area of the inner surface 50b. Since the magnetic flux reaching the brake drum 7 from the magnet 24 is narrowed, a strong magnetic field is applied to the brake drum 7. Therefore, the eddy current flowing through the braking drum 7 is increased and the braking force is increased.
[0017]
In the present invention, as shown in FIGS. 1 to 3, a guide cylinder 10 made of a non-magnetic material and having an inner space with a rectangular cross section is disposed inside a brake drum 7 coupled to the rotary shaft 1. A large number of ferromagnetic plates 15 are arranged at equal intervals in the circumferential direction on the outer cylinder part 10a of the outer cylinder, and the outer peripheral surface of the magnet support cylinder 14 made of a magnetic body arranged in the inner space of the guide cylinder 10 so as to be able to rotate forward and backward. In addition, two magnets 24 are coupled to each ferromagnetic plate 15 so as to be opposed to each other and the polarity with respect to the ferromagnetic plate 15 is different every two in the circumferential direction. The magnet support cylinder 14 is switched by forward / reverse rotation by the fluid pressure actuator 20 between a non-braking position that opposes each other and a braking position in which the magnet 24 having the same polarity faces the entire ferromagnetic plate 15. The eddy current reducer is not limited to other types of eddy current reducers. It can be applied.
[0018]
In the embodiment shown in FIGS. 6 and 7, a guide cylinder 10 made of a non-magnetic material and having an inner space with a rectangular cross section is disposed inside the brake drum 7 coupled to the rotary shaft 1. A large number of ferromagnetic plates 15 are arranged in the cylindrical portion 10a at equal intervals in the circumferential direction, and on the outer peripheral surface of the magnet support cylinder 14 made of a magnetic material disposed in the inner space of the guide cylinder 10 so as to be able to rotate forward and backward, The magnets 24 are coupled so that the polarities facing the respective ferromagnetic plates 15 are alternately different in the circumferential direction, and the two magnets 24 adjacent in the circumferential direction partially face each ferromagnetic plate 15 (see FIG. 6 ) and the brake position (state shown in FIG. 7 ) in which one magnet 24 is entirely opposed to each ferromagnetic plate 15 (see FIG. 7 ), the magnet support cylinder 14 is fluid pressure actuator 20 (see FIG. 1). by so switched to forward or reverse rotation, as shown in FIG. 4, the front 15 of the ferromagnetic plate 15 The tilted to the rotation direction rear side of the brake drum 7, by tilting the surface 15b after the plate member 15 in the rotational direction in front of the brake drum 7, the area of the outer surface 50a is smaller than the area of the inner surface 50b.
[0019]
In the embodiment shown in FIG. 8, a guide cylinder 10 made of a non-magnetic material and having an inner space with a rectangular cross section is disposed inside the brake drum 7 coupled to the rotary shaft 1. A large number of ferromagnetic plates 15 are arranged at equal intervals in the circumferential direction 10a, and on the outer surfaces of the movable magnet support cylinder 14 and the stationary magnet support cylinder 14A made of a magnetic material housed in the inner space of the guide cylinder 10, The magnets 24 and 24A are coupled so as to face the ferromagnetic plate 15 and have different polarities with respect to the ferromagnetic plate 15 alternately in the circumferential direction, and the magnets 24 and 24A having different polarities face the respective ferromagnetic plates 15 entirely. Movable magnet support between the non-braking position (state shown in FIG. 8 ) and the braking position (same as the state shown in FIG. 7 ) in which the magnets 24, 24A having the same polarity are opposed to the respective ferromagnetic plates 15 . The cylinder 14 is moved by a fluid pressure actuator 20 and a half arrangement pitch of magnets 24 is obtained. Only to be switched to forward or reverse rotation, as shown in FIG. 4, the front surface of the ferromagnetic plate 15 is inclined to the rotation direction rear side of the brake drum 7, the rotational direction of the plane braking drum 7 after the ferromagnetic plate 15 The area of the outer surface 50a is made smaller than the area of the inner surface 50b by inclining forward.
[0020]
In the embodiment shown in FIG. 9, a guide cylinder 10 made of a non-magnetic material and having an inner space with a rectangular cross section is disposed inside the brake drum 7 coupled to the rotary shaft 1. A large number of ferromagnetic plates 15 are arranged at equal intervals in the circumferential direction 10a, and each ferromagnetic plate 15 is provided on the outer surface of a magnet support tube 14 made of a magnetic material supported in the inner space of the guide tube 10 so as to be movable in the axial direction. The magnets 24 are coupled so that the polarities thereof are alternately different in the circumferential direction, the magnet support cylinder 14 protrudes into the brake drum 7, and each of the magnets 24 faces the ferromagnetic plate 15 as shown in the illustrated braking position (see FIG. 7 ) and the non-braking position at which the magnet support cylinder 14 is retracted from the braking drum 7 in the axial direction and the magnets 24 do not face the ferromagnetic plate 15, the fluid pressure actuator 20 and to switch back and forth movement in the axial direction by, FIG. As shown in the front surface of the ferromagnetic plate 15 is inclined to the rotation direction rear side of the brake drum 7, by tilting the rear surface of the ferromagnetic plate 15 in the rotational direction in front of the brake drum 7, the area of the outer surface 50a inner surface 50b Narrower than the area.
[0021]
【The invention's effect】
In the present invention, as described above, a guide cylinder having an inner space with a rectangular cross section made of a non-magnetic material is disposed inside a brake drum coupled to a rotating shaft, and the outer cylinder of the guide cylinder is equidistant in the circumferential direction. A large number of ferromagnetic plates are coupled to each other, and the outer peripheral surface of at least one magnet support cylinder supported in the inner space of the guide cylinder so as to be rotatable or axially movable is opposed to each ferromagnetic plate and In the eddy current reduction device formed by coupling magnets so that the polarities with respect to the ferromagnetic plate are alternately different in the circumferential direction, the plate thickness of the portion extending from the central portion of the ferromagnetic plate to the inner surface facing the magnet is made uniform, The portion of the front surface of the ferromagnetic plate that extends from the central portion of the plate thickness to the outer surface facing the brake drum is inclined rearward in the rotation direction of the brake drum, and the rear surface of the ferromagnetic plate is opposed to the brake drum from the central portion of the plate thickness. The part that reaches the outer surface is in front of the braking drum in the rotational direction. Is inclined, thereby smaller than the area of the area of the inner surface of the outer surface of the ferromagnetic plate, is provided with the retaining projection surrounding the ferromagnetic plate in the center of the plate thickness of the ferromagnetic plate, The magnetic flux reaching the braking drum from the magnet is narrowed by the ferromagnetic plate, the eddy current flowing through the braking drum is increased, and the braking force is increased.
[Brief description of the drawings]
FIG. 1 is a front sectional view of an eddy current reduction device to which the present invention is applied.
FIG. 2 is a side cross-sectional view of the eddy current reduction device when not braked.
FIG. 3 is a side sectional view of the eddy current reduction device during braking.
FIG. 4 is a side view of another ferromagnetic plate.
FIG. 5 is a perspective view showing a coupling structure of a ferromagnetic plate to an outer tube portion of a guide tube made of a thin stainless steel plate in a second eddy current reduction device to which the present invention is applied.
FIG. 6 is a side cross-sectional view of the third eddy current reduction device to which the present invention is applied during non-braking.
FIG. 7 is a side sectional view of the eddy current reduction device during braking.
FIG. 8 is a front cross-sectional view of the fourth eddy current reduction device to which the present invention is applied during non- braking.
FIG. 9 is a front sectional view at the time of braking of the fifth eddy current reduction device to which the present invention is applied;
[Explanation of symbols]
3: Brake drum 6: Spoke 7: Brake drum 8: Cooling fin 10: Guide tube 10a: Outer tube portion 10b: Inner tube portion 14: Magnet support tube 14A: Magnet support tube 15: Ferromagnetic plate 15a: Front surface 15b: Rear surface 15c: retaining protrusion 20: actuator 24: magnet 24A: magnet 25: opening 50a: outer surface 50b: inner surface 50c: side surface

Claims

A guide cylinder having a rectangular inner section made of a non-magnetic material is disposed inside the brake drum coupled to the rotating shaft, and a large number of ferromagnetic plates are coupled to the outer cylinder of the guide cylinder at equal intervals in the circumferential direction. The outer peripheral surface of at least one magnet support cylinder supported in the inner space of the guide cylinder so as to be rotatable or axially movable is opposed to each ferromagnetic plate and has a polarity in the circumferential direction. In the eddy current reduction device, in which the magnets are alternately coupled to each other, the thickness of the portion from the central portion of the ferromagnetic plate to the inner surface facing the magnet is made uniform, and the thickness of the front surface of the ferromagnetic plate is uniform. The portion from the central portion of the ferromagnetic plate to the outer surface facing the braking drum is inclined rearward in the rotational direction of the braking drum, and the portion of the rear surface of the ferromagnetic plate from the central portion of the plate thickness to the outer surface facing the braking drum is Tilt forward in the direction of rotation. Wherein the area of the outer surface of the ferromagnetic plate is smaller than the area of the inner surface, the eddy current deceleration, characterized in that a retaining projection surrounding the ferromagnetic plate in the center of the plate thickness of the ferromagnetic plate apparatus.