【発明の詳細な説明】
【0001】
【産業上の利用分野】本発明は、軽負荷時と重負荷時の
相違によって、ブラシの圧力を変動させ、機械損を減少
させることを目的としたものである。
【0002】
【従来の技術】従来、フォ−クリフト用直流電動機は起
動時の電流が定常時の3〜5倍と大きく、モ−タに流れ
る電流が最大電流を考慮してブラシやコミュテ−タの設
計を行っていた。
【0003】
【解決すべき課題】上述のように、従来は、フォ−クリ
フト用直流電動機は起動時の電流が定常時の3〜5倍と
大きく、モ−タに流れる電流が最大電流を考慮してブラ
シやコミュテ−タの設計を行っていたので、軽負荷時に
は必要のない圧力であり、機械損が大きくなるという課
題があった。本発明は、このような課題を解決すべく案
出されたものである。
【0004】
【課題を解決する手段】本発明は、ブラシとピグテイル
を取り付ける金具を磁性体とし、ブラシホルダ−にフィ
−ルドコイル間の亘線を数タ−ン巻き電磁石として構成
し、高負荷時、該亘線に流れる電流が大きくなると、ブ
ラシをコミュテ−タに強く押しつけ、反対に軽負荷時に
は亘線に流れる電流が小さくなり、バネによりブラシが
押し上げられ、ブラシのコミュテ−タへの押圧力を弱
め、上述の課題を解決したものである。
【0005】
【実施例】本発明の一実施例を図1に基づき説明する
と、1はコミュテ−タ、該コミュテ−タ1の外周にロッ
カ−2を配し、該ロッカ−2の上下、左右にブラシホル
ダ−3でブラシ7を摺動自在に取付ると共にタ−ミナル
4をも固定している。
【0006】上記ブラシ7の頂面の一点にピグティル6
の円錐状の一端を押しつけるように配し、スプリング8
がピグティル6の円錐状の一端を押し上げる方向で先端
と接するよう配置し、該ピグティル6の外周に該ピグテ
ィル6を中心として螺旋状に形成した亘線9が外挿して
いる。
【0007】
【発明の効果】本発明は、上述のように、ブラシとピグ
テイルを取り付ける金具を磁性体とし、ブラシホルダ−
にフィ−ルドコイル間の亘線を数タ−ン巻き電磁石とし
て構成し、高負荷時、該亘線に流れる電流が大きくなる
と、ブラシをコミュテ−タに強く押しつけ、反対に軽負
荷時には亘線に流れる電流が小さくなり、バネによりブ
ラシが押し上げられ、ブラシのコミュテ−タへの押圧力
を弱め、軽負荷時における、機械損を減少させることが
できる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has an object to reduce the mechanical loss by varying the brush pressure depending on the difference between a light load and a heavy load. It is. 2. Description of the Related Art Conventionally, a DC motor for a forklift has a current at the time of starting which is three to five times as large as that in a steady state, and a current flowing through the motor is a brush or a commutator in consideration of a maximum current. Had been designed. As described above, conventionally, a DC motor for a forklift conventionally has a current at start-up that is three to five times as large as a steady state, and the current flowing through the motor takes into consideration the maximum current. However, since the brush and the commutator are designed, the pressure is unnecessary when the load is light, and there is a problem that the mechanical loss increases. The present invention has been devised to solve such a problem. According to the present invention, a metal fitting for attaching a brush and a pigtail is made of a magnetic material, and a wire between the field coils is formed as a several-turn wound electromagnet in a brush holder, so that a high load is applied. When the current flowing through the bridging wire increases, the brush is strongly pressed against the commutator. On the contrary, when the load is light, the current flowing through the bridging wire decreases, and the brush is pushed up by the spring, and the pressing force of the brush against the commutator is increased. To solve the above-mentioned problem. An embodiment of the present invention will be described with reference to FIG. 1. Reference numeral 1 denotes a commutator, and a rocker 2 is arranged on the outer periphery of the commutator 1; The brush 7 is slidably mounted on the brush holder 3 and the terminal 4 is also fixed. At one point on the top surface of the brush 7, a pigtail 6 is provided.
And press one end of the cone
Are arranged so as to be in contact with the tip in a direction to push up one end of the conical shape of the pigtail 6, and a helical wire 9 spirally formed around the pigtail 6 is extrapolated around the outer periphery of the pigtail 6. As described above, according to the present invention, a metal fitting for attaching a brush and a pigtail is made of a magnetic material, and a brush holder is provided.
The wire between the field coils is formed as a several-turn wound electromagnet. When the load is high and the current flowing through the wire is large, the brush is strongly pressed against the commutator. The flowing current is reduced, the brush is pushed up by the spring, the pressing force of the brush on the commutator is reduced, and the mechanical loss at light load can be reduced.
【図面の簡単な説明】
【図1】本発明のモ−タの正面図を示す。
【符号の説明】
1 コミュテ−タ
2 ロッカ−
3 ブラシホルダ−
4 タ−ミナル
6 ピグティル
7 ブラシ
8 スプリング
9 亘線[Brief description of the drawings]
FIG. 1 shows a front view of a motor according to the present invention.
[Explanation of symbols]
1 Commutator
2 Lockers
3 brush holder
4 Terminal
6 Pigtil
7 brush
8 Spring
9 Watari Line