JPH05211761A - Eddy current type speed reducer - Google Patents

Abstract

PURPOSE:To weaken a magnetic field leaking to a braking drum from a magnet through a gap between ferromagnetic plates when no brake is applied so as to eliminate dragging torque without deteriorating the braking capacity of the drum at the braking time. CONSTITUTION:Guide pipes 10 made of a nonmagnetic material and having box-like cross sections are arranged in a braking drum 7 coupled with a rotating shaft. A large number of ferromagnetic plates 15 are coupled with the outer peripheral walls of the pipes 10 at regular intervals in the peripheral direction. Permanent magnets 14a faced to each plate 15 are coupled with a magnetic supporting ring 14 rotatably supported in the inner hollow section of the pipe 10. An opening 14b is provided at the central part in the peripheral direction on the outer peripheral surface of each magnet 14a. When the ring 14 is rotated by the half of the arranging pitch of the plates 15, the plates 15 are moved from a braking position at which each plate 15 completely overlaps each magnet 14a of the ring 14 to a non-braking position at which each plate 15 is positioned between two magnets 14a having different polarities and a short-circuited magnetic circuit is formed between the plates 15 and ring 14.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は主として大型車両の摩擦
ブレーキを補助する渦電流式減速装置、特に制動ドラム
の内周面と制動ドラムの内周面に対向して周方向等間隔
に並設した多数の永久磁石との間に介在する強磁性板の
位相を変えることにより制動と非制動の切換えを行う、
渦電流式減速装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to an eddy current type speed reducer for assisting a friction brake of a large vehicle, and more particularly, to an inner peripheral surface of a braking drum and an inner peripheral surface of a braking drum, which are arranged side by side at equal intervals in the circumferential direction. Switching between braking and non-braking is performed by changing the phase of a ferromagnetic plate that is interposed between a large number of permanent magnets,
The present invention relates to an eddy current type speed reducer.

【０００２】[0002]

【従来の技術】特開平1-298948号公報に開示される渦電
流式減速装置では、制動ドラムの内部に非磁性体からな
る断面箱形の案内筒を配設し、案内筒の外周壁に周方向
等間隔に多数の強磁性板を結合し、案内筒の内空部に回
動可能に支持した磁石支持輪に、各強磁性板に対向する
永久磁石（以下単に磁石という）を結合し、磁石支持輪
の位相を強磁性板の半配列ピツチだけ変えることによ
り、制動と非制動の切換えを行うことができる。2. Description of the Related Art In an eddy current type speed reducer disclosed in Japanese Patent Application Laid-Open No. 1-298948, a guide cylinder having a box-shaped cross section made of a non-magnetic material is provided inside a braking drum, and an outer peripheral wall of the guide cylinder is provided. A large number of ferromagnetic plates are connected at equal intervals in the circumferential direction, and permanent magnets (hereinafter simply referred to as magnets) that face each ferromagnetic plate are connected to a magnet support ring that is rotatably supported in the inner space of the guide cylinder. The braking and non-braking can be switched by changing the phase of the magnet supporting wheel by the half-arrangement pitch of the ferromagnetic plate.

【０００３】図６に示すように、上述の渦電流式減速装
置では、磁石支持輪１４の磁石１４ａは、強磁性板１５
と同じ配列ピツチｐで、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並設されている。非制動時、
強磁性板１５に対し磁石１４ａを半配列ピツチだけずら
すと、強磁性板１５は相隣接する異なる極性の磁石１４
ａに跨がり、実線で示す短絡的磁気回路を形成する。し
かし、磁石１４ａは相隣接する強磁性板１５の相互の隙
間ｓを経て制動ドラム７へ磁界を及ぼし、鎖線で示す磁
気回路を形成する恐れがある。この時、回転する制動ド
ラム７は洩れ磁界を横切る時引きずりトルクを受けるの
で、好ましくない。As shown in FIG. 6, in the above-mentioned eddy current type speed reducer, the magnet 14a of the magnet support ring 14 is made of a ferromagnetic plate 15.
Are arranged side by side in the same arrangement pitch p so that the polarities with respect to the ferromagnetic plate 15 are alternately different in the circumferential direction. When not braking,
When the magnets 14a are displaced by a half-arranged pitch with respect to the ferromagnetic plate 15, the ferromagnetic plates 15 are adjacent to each other and have different polarities.
A short-circuited magnetic circuit shown by the solid line is formed across a. However, the magnets 14a may exert a magnetic field on the braking drum 7 through the mutual clearance s between the adjacent ferromagnetic plates 15 to form a magnetic circuit indicated by a chain line. At this time, the rotating braking drum 7 receives drag torque as it crosses the leakage magnetic field, which is not preferable.

【０００４】[0004]

【発明が解決しようとする課題】本発明の目的は上述の
問題に鑑み、制動時の制動能力を損わないで、非制動時
磁石から強磁性板の相互の隙間を経て制動ドラムへ洩れ
る磁界を効果的に抑え、引きずりトルクを解消する、渦
電流式減速装置を提供することにある。SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to prevent a magnetic field from leaking from a magnet during non-braking to a braking drum through a mutual gap between ferromagnetic plates without impairing braking ability during braking. It is an object of the present invention to provide an eddy current type speed reducer that effectively suppresses the above and eliminates drag torque.

【０００５】[0005]

【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箱形の案内筒を配設し、案内筒
の外周壁に周方向等間隔に多数の強磁性板を結合し、案
内筒の内空部に回動可能に支持した磁石支持輪に、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
互に異なるように永久磁石を結合し、各永久磁石の周方
向中央部分の強磁性板に対する面積を縮小したものであ
る。In order to achieve the above object, according to the present invention, a guide cylinder having a box-shaped cross section made of a non-magnetic material is provided inside a braking drum connected to a rotary shaft. A large number of ferromagnetic plates are connected to the outer peripheral wall of the magnet at equal intervals in the circumferential direction, and the magnet support ring rotatably supported in the inner space of the guide cylinder faces each ferromagnetic plate and has a polarity relative to the ferromagnetic plates. The permanent magnets are coupled so as to be alternately different in the circumferential direction, and the area of the central portion in the circumferential direction of each permanent magnet with respect to the ferromagnetic plate is reduced.

【０００６】[0006]

【作用】制動時、強磁性板は磁石支持輪の磁石に全面的
に重なる。各磁石の磁界は強磁性板を透過して制動ドラ
ムの内周面に垂直に作用する。回転する制動ドラムが磁
界を横切る時、制動ドラムに渦電流が流れ、制動ドラム
は制動トルクを受ける。[Function] During braking, the ferromagnetic plate entirely overlaps the magnets of the magnet supporting wheel. The magnetic field of each magnet penetrates the ferromagnetic plate and acts perpendicularly on the inner peripheral surface of the braking drum. As the rotating braking drum traverses the magnetic field, eddy currents flow in the braking drum and the braking drum receives braking torque.

【０００７】非制動時、磁石支持輪を強磁性板の半配列
ピツチ分だけ回動すると、強磁性板は相隣接する極性が
異なる２つの磁石に跨がり、強磁性板と磁石支持輪との
間に短絡的磁気回路を形成する。この時、各磁石の周方
向中央部分が強磁性板の相互の隙間へ臨むが、磁石の中
央部分は開口または切欠を設けられ、強磁性板ないし制
動ドラムとの対向面積が他の部分よりも縮小されている
ので、磁石が制動ドラムへ及ぼす洩れ磁界は非常に弱く
なり、制動ドラムは引きずりトルクを受けない。When the magnet support wheel is rotated by a half-arranged pitch of the ferromagnetic plate during non-braking, the ferromagnetic plate straddles two adjacent magnets of different polarities, and the ferromagnetic plate and the magnet support wheel are separated from each other. A short circuit magnetic circuit is formed between them. At this time, the central portion in the circumferential direction of each magnet faces the mutual gap between the ferromagnetic plates, but the central portion of the magnet is provided with an opening or notch, and the area facing the ferromagnetic plate or the braking drum is larger than that of the other portions. Due to the reduction, the leakage field exerted by the magnet on the braking drum is very weak and the braking drum does not receive drag torque.

【０００８】[0008]

【実施例】図１は本発明による渦電流式減速装置の側面
断面図、図２は同正面断面図である。本発明による渦電
流式減速装置は、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不動の案内筒１０
と、案内筒１０の内空部に回動可能に支持した磁石支持
輪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にスプライン嵌合固定した取付フランジ
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スポーク６に、冷
却フイン８を備えた制動ドラム７の一端が結合される。1 is a side sectional view of an eddy current type speed reducer according to the present invention, and FIG. 2 is a front sectional view of the same. The eddy current type speed reducer according to the present invention includes, for example, a braking drum 7 formed of a conductor coupled to the output rotary shaft 1 of a vehicle transmission, and a braking drum 7.
An immovable guide tube 10 made of a non-magnetic material disposed inside
And a magnet support wheel 14 rotatably supported in the inner space of the guide cylinder 10. The braking drum 7 is such that the flange portion 5a of the boss 5 and the end wall portion of the braking drum 3 of the parking brake are superposed on the mounting flange 2 that is spline-fitted and fixed to the rotating shaft 1, and the plurality of bolts 4 and nuts are provided. It is concluded by. One end of a braking drum 7 having a cooling fin 8 is coupled to the spokes 6 extending radially from the boss 5.

【０００９】断面箱形の案内筒１０は例えば断面コ字形
をなす筒体に環状の蓋板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の外周壁１０ａに多数の強磁性板
（ポールピース）１５が周方向等間隔（図３に示す配列
ピツチｐを参照）に結合される。好ましくは、強磁性板
１５は案内筒１０の成形時鋳ぐるまれる。磁石支持輪１
４は案内筒１０の内空部、詳しくは内周壁１０ｂに軸受
１２により回動可能に支持される。The guide cylinder 10 having a box-shaped cross section is formed by connecting an annular cover plate 11 to a cylindrical body having a U-shaped cross section, for example. The guide tube 10 is fixed to the gear box of the transmission by any suitable means. A large number of ferromagnetic plates (pole pieces) 15 are coupled to the outer peripheral wall 10a of the guide cylinder 10 at equal intervals in the circumferential direction (see the array pitch p shown in FIG. 3). Preferably, the ferromagnetic plate 15 is cast when forming the guide cylinder 10. Magnet support wheel 1
4 is rotatably supported by a bearing 12 on the inner space of the guide cylinder 10, more specifically, on the inner peripheral wall 10b.

【００１０】案内筒１０の左端壁に、好ましくは３つの
流体圧アクチユエータ２０が周方向等間隔に結合され
る。流体圧アクチユエータ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、磁石支持輪１４から案内筒１０の左端壁の
スリツトを経て突出する腕１６に連結される。磁石支持
輪１４は各強磁性板１５に対向する多数の磁石１４ａを
結合される。図２に示すように、磁石支持輪１４は磁性
体からなり、各強磁性板１５に対向する磁石１４ａは、
極性が周方向に交互に異なるように配設される。Three fluid pressure actuators 20, preferably, are connected to the left end wall of the guide cylinder 10 at equal intervals in the circumferential direction. The fluid pressure actuator 20 is formed by fitting a piston 17 in a cylinder 18, and a rod projecting from the piston 17 to the outside is connected to an arm 16 projecting from a magnet supporting wheel 14 through a slit of a left end wall of the guide cylinder 10. . The magnet support ring 14 is coupled with a large number of magnets 14 a facing each ferromagnetic plate 15. As shown in FIG. 2, the magnet support ring 14 is made of a magnetic material, and the magnets 14 a facing the ferromagnetic plates 15 are
The polarities are arranged so as to be alternately different in the circumferential direction.

【００１１】図４に示すように、本発明によれば、各磁
石１４ａは周方向中央部分に長方形の開口１４ｂを設け
られる。磁石１４ａの中央部分が強磁性板１５ないし制
動ドラム７に対向する面積は開口１４ｂにより縮小さ
れ、磁石１４ａの中央部分が制動ドラム７へ及ぼす磁界
は他の部分よりも弱くなる。磁石１４ａの中央部分の厚
さは他の部分と同じであるので、磁石支持輪１４に対す
る結合強度には問題がなく、磁石１４ａの中央部分が発
熱などにより亀裂を生じる恐れはない。磁石１４ａの中
央部分に開口の代りに、薄い底のあるくぼみを設けれ
ば、磁石の強度は高くなる。As shown in FIG. 4, according to the present invention, each magnet 14a is provided with a rectangular opening 14b in the central portion in the circumferential direction. The area where the central portion of the magnet 14a faces the ferromagnetic plate 15 or the braking drum 7 is reduced by the opening 14b, and the magnetic field exerted on the braking drum 7 by the central portion of the magnet 14a becomes weaker than the other portions. Since the thickness of the central portion of the magnet 14a is the same as that of the other portions, there is no problem in the coupling strength to the magnet support ring 14, and there is no possibility that the central portion of the magnet 14a will be cracked due to heat generation or the like. If a recess with a thin bottom is provided in the central portion of the magnet 14a instead of the opening, the strength of the magnet is increased.

【００１２】次に、本発明による渦電流式減速装置の作
動について説明する。図２に示すように、制動時、各磁
石１４ａは各強磁性板１５に全面的に対向し、強磁性板
１５を経て制動ドラム７に磁界を及ぼす。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。この時、磁石
１４ａから強磁性板１５、制動ドラム７、隣りの強磁性
板１５、隣りの磁石１４ａ、磁石支持輪１４へと磁気回
路が生じる。磁石１４ａの中央部分の面積は開口１４ｂ
により縮小されているが、制動時の制動能力には殆ど影
響しない。Next, the operation of the eddy current type speed reducer according to the present invention will be described. As shown in FIG. 2, during braking, each magnet 14a entirely faces each ferromagnetic plate 15 and exerts a magnetic field on the braking drum 7 via the ferromagnetic plate 15. When the rotating braking drum 7 crosses the magnetic field, an eddy current flows in the braking drum 7, and the braking drum 7 receives a braking torque. At this time, a magnetic circuit is generated from the magnet 14a to the ferromagnetic plate 15, the braking drum 7, the adjacent ferromagnetic plate 15, the adjacent magnet 14a, and the magnet supporting wheel 14. The area of the central portion of the magnet 14a is the opening 14b.
However, the braking ability during braking is hardly affected.

【００１３】非制動時、流体圧アクチユエータ２０によ
り磁石支持輪１４を強磁性板１５の半配列ピツチｐ／２
分だけ回動すると、図３に示すように、極性が異なる２
つの磁石１４ａが各強磁性板１５に対向する。各強磁性
板１５と磁石支持輪１４との間に短絡的磁気回路が生
じ、磁石１４ａは磁界を制動ドラム７に及ぼさない。When the brake is not applied, the magnet support wheel 14 is moved by the fluid pressure actuator 20 so that the magnet support wheel 14 is half-arranged with the ferromagnetic plate 15 in a pitch p / 2.
When it is rotated by an amount, as shown in FIG.
One magnet 14a faces each ferromagnetic plate 15. A short-circuiting magnetic circuit occurs between each ferromagnetic plate 15 and the magnet support wheel 14, and the magnet 14a does not apply a magnetic field to the braking drum 7.

【００１４】非制動時、各磁石１４ａの開口１４ｂを有
する中央部分が、相隣接する強磁性板１５の相互の隙間
ｓへ臨むが、磁石１４ａの中央部分が制動ドラム７の内
周面に対向する面積は他の部分よりも狭いことから、磁
石１４ａから強磁性板１５の相互の隙間ｓを経て制動ド
ラム７へ洩れる磁界は極めて弱く、制動ドラム７は引き
ずりトルクを殆ど受けない。At the time of non-braking, the central portion of each magnet 14a having the opening 14b faces the mutual clearance s between the adjacent ferromagnetic plates 15, but the central portion of the magnet 14a faces the inner peripheral surface of the braking drum 7. Since the area covered is smaller than other areas, the magnetic field leaking from the magnet 14a to the braking drum 7 through the mutual clearance s between the ferromagnetic plates 15 is extremely weak, and the braking drum 7 receives almost no drag torque.

【００１５】図５に示す実施例では、磁石１４ａの周方
向中央部分の前後縁部に切欠１４ｄを設けてくびれ部１
４ｃを形成し、磁石１４ａの中央部分の強磁性板１５な
いし制動ドラム７に対向する面積を縮小したものであ
り、図４の磁石１４ａと同様の効果を奏する。In the embodiment shown in FIG. 5, a notch 14d is provided at the front and rear edges of the central portion of the magnet 14a in the circumferential direction to form the constricted portion 1.
4c is formed to reduce the area facing the ferromagnetic plate 15 or the braking drum 7 in the central portion of the magnet 14a, and has the same effect as the magnet 14a in FIG.

【００１６】上述の実施例では、磁石支持輪１４を流体
圧アクチユエータにより強磁性板１５の半配列ピツチ分
だけ正逆回動するようにしたが、電動機により回動して
もよく、また磁石支持輪１４を固定し、代りに案内筒１
０を回動してもよい。In the above-described embodiment, the magnet support wheel 14 is rotated forward and backward by the fluid pressure actuator by the amount of the half-arranged pitch of the ferromagnetic plate 15, but it may be rotated by an electric motor. The wheel 14 is fixed and instead the guide tube 1
You may rotate 0.

【００１７】[0017]

【発明の効果】本発明は上述のように、＠したものであ
り、非制動時、各磁石の中央部分は相隣接する強磁性板
の相互の隙間へ臨むが、各磁石の周方向中央部分の制動
ドラムに対向する面積が狭くなつていることから、各磁
石の中央部分から相隣接する強磁性板の相互の隙間を経
て制動ドラムへ洩れる磁界の強さは極めて弱く、制動ド
ラムに及ぼす引きずりトルクは無視できるものとなり、
動力の損失を抑止できる。As described above, the present invention is characterized by the fact that the central portions of the magnets face the mutual gaps between the adjacent ferromagnetic plates when not braking, but the central portions in the circumferential direction of the magnets. Since the area of the magnet facing the braking drum is narrow, the strength of the magnetic field leaking from the central part of each magnet to the braking drum through the gap between the adjacent ferromagnetic plates is extremely weak, and the drag exerted on the braking drum is reduced. Torque becomes negligible,
Power loss can be suppressed.

【００１８】各磁石の中央部分は他の部分と同じ厚さを
有するので、磁石自体の強度や磁石支持輪との結合強度
が損われない。Since the central portion of each magnet has the same thickness as the other portions, the strength of the magnet itself and the coupling strength with the magnet support ring are not impaired.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明に係る渦電流式減速装置の側面断面図で
ある。FIG. 1 is a side sectional view of an eddy current type speed reducer according to the present invention.

【図２】制動時の強磁性板と磁石支持輪との関係を示す
部分的正面断面図である。FIG. 2 is a partial front cross-sectional view showing a relationship between a ferromagnetic plate and a magnet support wheel during braking.

【図３】非制動時の強磁性板と磁石支持輪との関係を示
す部分的正面断面図である。FIG. 3 is a partial front cross-sectional view showing a relationship between a ferromagnetic plate and a magnet support wheel when not braking.

【図４】磁石の斜視図である。FIG. 4 is a perspective view of a magnet.

【図５】磁石の変更実施例を示す斜視図である。FIG. 5 is a perspective view showing a modified embodiment of the magnet.

【図６】従来の渦電流式減速装置を示す正面断面図であ
る。FIG. 6 is a front sectional view showing a conventional eddy current type speed reducer.

【符号の説明】[Explanation of symbols]

１：回転軸 ７：制動ドラム １０：案内筒 １４：磁
石支持輪 １４ａ：磁石 １４ｂ：開口 １４ｃ：くびれ部 １５：強磁性板1: Rotating shaft 7: Braking drum 10: Guide cylinder 14: Magnet support ring 14a: Magnet 14b: Opening 14c: Constricted portion 15: Ferromagnetic plate

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】回転軸に結合した制動ドラムの内部に非磁
性体からなる断面箱形の案内筒を配設し、案内筒の外周
壁に周方向等間隔に多数の強磁性板を結合し、案内筒の
内空部に回動可能に支持した磁石支持輪に、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
なるように永久磁石を結合し、各永久磁石の周方向中央
部分の強磁性板に対する面積を縮小したことを特徴とす
る、渦電流式減速装置。1. A guide cylinder having a box-shaped cross section made of a non-magnetic material is disposed inside a braking drum connected to a rotary shaft, and a large number of ferromagnetic plates are connected to an outer peripheral wall of the guide cylinder at equal intervals in the circumferential direction. , A permanent magnet is connected to a magnet support wheel rotatably supported in the inner space of the guide cylinder so as to face each ferromagnetic plate and have polarities alternately different from each other in the circumferential direction. The eddy current type speed reducer characterized in that the area of the central portion in the circumferential direction with respect to the ferromagnetic plate is reduced.