【発明の詳細な説明】[Detailed description of the invention]
本発明は、直流小型モータの整流子用摺動接点
材料（以下「摺動接点材料」という。）の改良に
関する。
従来より小型モータの整流子外周の接点片を作
る摺動接点材料としては主としてはAg―Ｃが用
いられてきたが、Ag―Ｃは潤滑性に優れている
が、軟かい為、整流子の回転摺動中消耗し易く、
接触抵抗が高く且つ不安定であるという欠点があ
つた。
本発明はかかる欠点を解消すべくなされたもの
で、硬さを増して消耗を減じて接触抵抗を低く安
定させた摺動接点材料を提供せんとするものであ
る。
本発明の摺動接点材料は、C0.1〜３重量％、
TaまたはNb0.5〜１重量％及び残部Agの銀合金
から成るものである。
かかる本発明の摺動接点材料に於いて、Ag中
に、C0.1〜３重量％とTaまたはNbを0.5〜１重
量％添加するのは、Ag―Ｃの硬さを高くして小
型モータの整流子の回転中外周の接点片が消耗す
るのを防止し、接触抵抗を低く且つばらつきの小
さい安定したものにする為で、0.5重量％未満で
はAg―Ｃの消耗を減少させる効果が小さく、３
重量％を超えると酸化物の生成量が多くなつて、
接点片の接触抵抗が高く且つばらつきが大きくな
つて不安定となりやすくなるものである。
次に本発明による摺動接点材料と従来の摺動接
点材料にて作つた小型モータの整流子外周の接点
片について説明する。
後記の表の左欄に示す成分組成の本発明の実施
例である摺動接点材料と従来例の摺動接点材料に
て図面に示す如く小型モータの直径10mm、長さ10
mmの整流子１の外周に厚さ0.5mmの接点片１ａが
形成され、この接点片１ａの外周面の上下に、
Au―Ag―Cu―Pt合金より成る直径0.3mm、長さ
10mmの３本の刷子線材２を有する刷子接点３を相
対向するように摺接させて、後記の試験条件にて
整流子の回転試験を行い、接点片１ａの消耗量と
接触抵抗を測定した処、後記の表の右欄に示すよ
うな結果を得た。
試験条件
電 圧 ：12V
電 流 ：直流250mA
整流子の回転数 ：2000回転／分
整流子の回転時間：300時間
刷子接点の接触力：５ｇ
The present invention relates to improvements in sliding contact materials for commutators of small DC motors (hereinafter referred to as "sliding contact materials"). Conventionally, Ag-C has been mainly used as a sliding contact material to make the contact pieces around the commutator of small motors.Although Ag-C has excellent lubricity, it is soft and can cause damage to the commutator. Easy to wear out during rotation and sliding,
The drawbacks were high contact resistance and instability. The present invention has been made to overcome these drawbacks, and aims to provide a sliding contact material that has increased hardness, reduced wear and tear, and has a low and stable contact resistance. The sliding contact material of the present invention contains 0.1 to 3% by weight of C,
It consists of a silver alloy containing 0.5 to 1% by weight of Ta or Nb and the balance being Ag. In the sliding contact material of the present invention, adding 0.1 to 3% by weight of C and 0.5 to 1% by weight of Ta or Nb to Ag increases the hardness of Ag-C and improves the performance of small motors. This is to prevent the contact pieces on the outer periphery from being worn out during the rotation of the commutator, and to keep the contact resistance low and stable with little variation.If it is less than 0.5% by weight, the effect of reducing Ag-C wear is small. ,3
If the weight percentage is exceeded, the amount of oxides produced increases,
The contact resistance of the contact piece is high and the variation becomes large, making it easy to become unstable. Next, a contact piece for the outer periphery of a commutator of a small motor made of a sliding contact material according to the present invention and a conventional sliding contact material will be explained. Using the sliding contact material according to the embodiment of the present invention and the conventional sliding contact material having the composition shown in the left column of the table below, a small motor with a diameter of 10 mm and a length of 10 mm is used as shown in the drawing.
A contact piece 1a with a thickness of 0.5 mm is formed on the outer periphery of the commutator 1 with a diameter of 1.5 mm.
Made of Au-Ag-Cu-Pt alloy, diameter 0.3mm, length
A commutator rotation test was performed under the test conditions described below by sliding brush contacts 3 having three 10 mm brush wires 2 so as to face each other, and the wear amount and contact resistance of the contact piece 1a were measured. The results shown in the right column of the table below were obtained. Test conditions Voltage: 12V Current: DC 250mA Commutator rotation speed: 2000 rotations/min Commutator rotation time: 300 hours Contact force of brush contact: 5g
【表】
前記の表で明らかなように従来例の整流子外周
の接点片の消耗量は40〜60μｍであるのに対し、
実施例の整流子外周の接点片の消耗量は10〜20μ
ｍで、著しく少なく耐消耗性に優れていることが
判る。また従来例の接点片では接触抵抗は25〜
40mΩであるのに対し、実施例の接点片では接触
抵抗は10〜15mΩで、著しく低く且つばらつきが
小さく安定していることが判る。
以上詳記した通り本発明の摺動接点材料は、硬
さが高いので、これにより作つた小型モータの整
流子外周の接点片は摺動中に消耗することがな
く、接触抵抗が低く且つばらつきが少なく安定す
るものである。[Table] As is clear from the table above, the amount of wear of the contact pieces on the outer circumference of the commutator in the conventional example is 40 to 60 μm, whereas
The wear amount of the contact piece on the outer circumference of the commutator in the example is 10 to 20μ
m, it can be seen that the wear resistance is extremely low and excellent in abrasion resistance. In addition, the contact resistance of the conventional contact piece is 25~
40 mΩ, whereas the contact resistance of the contact piece of the example was 10 to 15 mΩ, which is extremely low and stable with little variation. As detailed above, since the sliding contact material of the present invention has high hardness, the contact pieces on the outer periphery of the commutator of a small motor made using this material will not wear out during sliding, and the contact resistance will be low and uneven. It is stable because of the small amount of
【図面の簡単な説明】[Brief explanation of drawings]
図は小型モータの整流子と摺動接点との接触状
態を示す斜視図である。
１……整流子、１ａ……接点片、２……刷子線
材、３……刷子接点。
The figure is a perspective view showing a state of contact between a commutator and a sliding contact of a small motor. 1...Commutator, 1a...Contact piece, 2...Brush wire, 3...Brush contact.