【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。
従来より摺動接点材料の一つとして耐硫化性の
優れたAg−Zn合金が用いられてきたが、Ag−
Zn合金は硬さが低く耐摩耗性に劣るので、この
Ag−Zn合金で小型モータの整流子の外周の接点
片を製作して使用した場合には刷子接点との接触
により摩耗粉が生じ、ノイズ発生の原因となり、
また刷子接点との接触抵抗が変化し、整流子の回
転速度が大きくばらついて不安定なものとなつて
いた。
本発明は、かかる欠点を解消すべくなされたも
のであり、Ag−Zn合金の硬さを高め耐摩性を向
上させると共に接触抵抗を低く安定させ整流子の
回転数のばらつきを少なくして安定させた摺動接
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の一つは、Zn1〜５重量
％、Sb0.5〜３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、１〜５％のZnを添加するのは、Agの耐硫化
性を向上させる為で、１％未満ではその効果が現
われず、10％を超えると酸化物の生成量が多くな
り接触抵抗が高く不安定になりやすくなるもので
ある。またSb0.1〜３％添加するのは、AgとZnの
固溶体の他に前記元素とZnとの金属間化合物の
析出物を分散させて、Ag−Znの硬さを高め耐摩
耗性を向上させる為で、0.5％未満ではAgとの金
属間化合物の析出物が少なく分散が不十分でAg
−Znの硬さを高めることができなく、耐摩耗性
が向上せず、３％を超えるとZnとの金属間化合
物の析出粒子が多く且つ大きくなり、その粒子が
酸化して接触抵抗が高く不安定になるものであ
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の接点片に
ついて説明する。
後記の表の右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、厚さ0.2mmの接点片を作り、この接点片を図
面に示す如く外周に３枚備えた直径６mm、長さ９
mmの整流子１の外周面の上下に、Au−Ag−Cu−
Ptより成る直径0.25mm、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１の回転試験
を行い、接点片１ａの摩耗量と整流子１の回転数
のばらつきを測定した処、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60ｍＡ
整流子の回転数：2800回転／分
整流子の回転時間：500時間
刷子接点の接触力：５ｇ／３本
The present invention relates to improvements in sliding contact materials for commutators of small DC motors (hereinafter referred to as "sliding contact materials"). Ag-Zn alloy, which has excellent sulfidation resistance, has traditionally been used as a sliding contact material.
Since Zn alloy has low hardness and poor wear resistance, this
When a contact piece for the outer periphery of a commutator of a small motor is made of Ag-Zn alloy and used, abrasion powder is generated due to contact with the brush contact, causing noise.
In addition, the contact resistance with the brush contacts changed, and the rotation speed of the commutator varied greatly and became unstable. The present invention has been made in order to eliminate these drawbacks, and it increases the hardness of the Ag-Zn alloy, improves its wear resistance, and also reduces and stabilizes the contact resistance at a low and stable level, thereby reducing variations in the rotational speed of the commutator. The purpose of this invention is to provide a sliding contact material. One of the sliding contact materials of the present invention consists of a silver alloy of 1-5% by weight of Zn, 0.5-3% by weight of Sb, and the balance Ag. In the sliding contact material of the present invention, 1 to 5% of Zn is added to Ag in order to improve the sulfidation resistance of Ag, and if it is less than 1%, the effect will not appear. %, the amount of oxide produced increases, resulting in high contact resistance and instability. In addition, adding 0.1 to 3% of Sb disperses precipitates of intermetallic compounds between the above elements and Zn in addition to the solid solution of Ag and Zn, increasing the hardness of Ag-Zn and improving wear resistance. If it is less than 0.5%, there will be few precipitates of intermetallic compounds with Ag, and the dispersion will be insufficient.
- It is not possible to increase the hardness of Zn, and the wear resistance does not improve. If it exceeds 3%, the precipitated particles of intermetallic compounds with Zn become large and large, and the particles oxidize, resulting in high contact resistance. It becomes unstable. Next, a contact piece for 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. A contact piece with a thickness of 0.2 mm was made 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 right column of the table below, and this contact piece is shown in the drawing. 6 mm in diameter and 9 in length with 3 pieces on the outer periphery
Au-Ag-Cu-
A rotation test was performed on the commutator 1 under the test conditions described below, with the brush contacts 3 having three brush wires 2 made of Pt having a diameter of 0.25 mm and a length of 10 mm in sliding contact facing each other. When the wear amount of 1a and the variation in the rotation speed of commutator 1 were measured, the results shown in the right column of the table below were obtained. Test conditions Voltage: 12V Current: DC 60mA Commutator rotation speed: 2800 rotations/min Commutator rotation time: 500 hours Brush contact force: 5g/3 pieces
【表】
前記の表で明らかなように従来例の接点片の摩
耗量は５〜7μであつたのに対し、実施例の接点
片の摩耗量は2.5〜3μｍで著しく減少していて耐
摩耗性に優れていることが判る。また従来例の接
点片を有する整流子の回転数のばらつきは８〜11
％であつたのに対し、実施例の接点片を有する整
流子の回転数のばらつきは３〜４％で著しく減少
していることが判る。
以上詳記した通り本発明の慴動接点材料は、硬
さが高く耐摩耗性に優れているので、これにより
作つた小型モータの整流子の接点片は刷子接点と
の慴動時摩耗粉の発生が無い。従つてノイズが発
生することがなく接触抵抗が低く安定しているの
で、小型モータの整流子の回転数のばらつきが大
幅に減少する等の優れた効果がある。[Table] As is clear from the above table, the wear amount of the contact piece of the conventional example was 5 to 7 μm, while the amount of wear of the contact piece of the example was 2.5 to 3 μm, which was significantly reduced, indicating that the contact piece of the conventional example had wear resistance. It turns out that they have excellent sex. In addition, the variation in the rotation speed of the commutator with the conventional contact piece is 8 to 11
%, whereas it can be seen that the variation in the rotational speed of the commutator having the contact piece of the example is significantly reduced to 3 to 4%. As detailed above, the sliding contact material of the present invention has high hardness and excellent wear resistance, so contact pieces for commutators of small motors made using this material can prevent abrasion powder from sliding with brush contacts. No outbreak. Therefore, since no noise is generated and the contact resistance is low and stable, there are excellent effects such as significantly reducing variations in the rotation speed of the commutator of a small motor.
【図面の簡単な説明】[Brief explanation of drawings]
図は小型モータの整流子と刷子接点との接触状
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 the state of contact between the commutator and brush contacts of a small motor. 1...Commutator, 1a...Contact piece, 2...Brush wire, 3...Brush contact.