【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、
潤滑性に優れたAg―Zn合金が用いられてきた
が、Ag―Zn合金の摺動接点材料は酸化し易く、
接触抵抗が高く不安定になるという欠点があり、
従つてこの摺動接点材料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合金の酸化を抑制し、耐硫
化、潤滑性を維持しつつ耐消耗性を向上させ、し
かも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、Zn1〜５重量％、
Be、Nb及びTaの内の少なくとも一種を合計で
0.5〜２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重量％（以下、「ｗ／ｏ」という。）の
Znを添加した以外にBe，Nb及びTaの内の少な
くとも一種を合計で0.5〜2w／ｏ添加するのは、
これら元素がZnよりも酸化し易いので、これら
の元素の添加された材料より成る整流子の外周の
接点片はAg―Zn合金での酸化％が抑制され、つ
まり前記の添加された元素の酸化により、ZnOの
生成が抑制され、Ag―Zn合金の有する耐硫化
性、潤滑性が維持されて耐消耗性が向上すると共
に接触抵抗が低く安定するからであり、0.5w／
ｏ未満ではAg―Zn合金での酸化が抑制されず、
つまりZnOが生成されて接触抵抗が高く不安定に
なり、2w／ｏを超えるとAg―Zn合金の有する耐
硫化性、潤滑性等の特性を損ない耐消耗性が低下
するので、結局0.5〜2w／ｏの添加が必要であ
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
て図面に示す如く小型モータの直径６mm、長さ９
mmの整流子１の外周に厚さ0.2mm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0.25mm、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"). As one of the sliding contact materials, sulfur resistance and
Ag-Zn alloys with excellent lubricity have been used, but sliding contact materials made of Ag-Zn alloys are easily oxidized.
It has the disadvantage of high contact resistance and instability.
Therefore, if this sliding contact material is used to manufacture and use a contact piece for the outer circumference of a commutator of a small motor, the contact resistance with the brush contact will change, and the rotation speed of the commutator will vary widely and become unstable. It was becoming. The present invention was made in order to eliminate these drawbacks, and suppresses oxidation of the Ag-Zn alloy, improves wear resistance while maintaining sulfidation resistance and lubricity, and further stabilizes contact resistance at a low level. The present invention aims to provide a sliding contact material. The sliding contact material of the present invention contains 1 to 5% by weight of Zn,
At least one of Be, Nb and Ta in total
It consists of a silver alloy of 0.5 to 2% by weight and the balance being Ag. In the sliding contact material of the present invention, 1 to 5% by weight (hereinafter referred to as "w/o") of Ag is added to the sliding contact material of the present invention.
Adding a total of 0.5 to 2 w/o of at least one of Be, Nb, and Ta in addition to Zn is
Since these elements are more easily oxidized than Zn, the contact pieces on the outer periphery of the commutator made of materials to which these elements are added have a suppressed oxidation percentage in the Ag-Zn alloy. This is because the formation of ZnO is suppressed, the sulfidation resistance and lubricity of the Ag-Zn alloy are maintained, the wear resistance is improved, and the contact resistance is low and stable.
If it is less than o, oxidation in the Ag-Zn alloy is not suppressed,
In other words, ZnO is generated and the contact resistance becomes high and unstable, and if it exceeds 2w/o, the characteristics such as sulfidation resistance and lubricity of the Ag-Zn alloy are impaired and the wear resistance decreases, so in the end 0.5 to 2w It is necessary to add /o. 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. 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, a small motor with a diameter of 6 mm and a length of 9 mm is used as shown in the drawing.
A contact piece 1a with a thickness of 0.2 mm is formed on the outer periphery of a commutator 1 of mm, and above and below the outer peripheral surface of this contact piece 1a,
Made of Au-Ag-Cu-Pt alloy, diameter 0.25mm, length
A rotation test was performed on the commutator 1 under the test conditions described below, with the brush contacts 3 having three 10 mm brush wires 2 facing each other in sliding contact, and the wear amount of the contact piece 1a and the commutator 1 were measured. When we measured the variation in rotational speed, we obtained the results shown in the right column of the table below. Test conditions Voltage: 12V Current: DC 60mA Commutator rotation speed: 2800 rotations/min Commutator rotation time: 500 hours Contact force of brush contacts: 5g/3 pieces
【表】
前記の表で明らかなように従来例の接点片の消
耗量は５〜7μmであつたのに対し、実施例の接点
片の消耗量は2.5〜5.0μmで著しく減少していて耐
消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３〜5.5％で著しく減
少していることが判る。これはひとえに実施例の
接点片がAg―Zn合金での酸化が抑制されて接触
抵抗が低く安定しているからに他ならない。
以上詳記した通り本発明の摺動接点材料は、
Ag―Zn合金の酸化が抑制され、耐硫化性，潤滑
性が維持されているので、これにより作つた小型
モータの整流子の接点片の耐消耗性は著しく向上
するものである。Ag―Zn合金の酸化が抑制され
て接触抵抗が低く安定しているので、小型のモー
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 amount of wear 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 5.0 μm, which was significantly reduced, indicating durability. It can be seen that it has excellent consumability. 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 5.5%. This is simply because the contact piece of the example has a low and stable contact resistance due to suppressed oxidation of the Ag--Zn alloy. As detailed above, the sliding contact material of the present invention is
Since oxidation of the Ag-Zn alloy is suppressed and sulfidation resistance and lubricity are maintained, the wear resistance of commutator contact pieces for small motors made using this alloy is significantly improved. Since the oxidation of the Ag-Zn alloy is suppressed and the contact resistance is low and stable, it has excellent effects such as greatly reducing variations in the rotation speed of the commutator of small motors.
【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.