JP2006050772A - Electric brush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric brush in which electric loss can be reduced without losing sliding characteristics even after being left under an atmosphere of high temperature and high humidity, and that reduces abrasion speed without causing a voltage drop at a lead wire embedded portion in particular to increase. <P>SOLUTION: A sliding face of the electric brush is of a two-layered structure of a high resistance layer and a low resistance layer or of a three-layered structure of the high resistance layer, a medium resistance layer, and the low resistance layer at the top, and the lead wire is inserted into a lead-wire insertion hole formed in an upper portion at the opposite side to the sliding face. In this electric brush, a metal layer or a metal-alloy layer is formed on the circumferential surface of the wall of the lead-wire insertion hole. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electric brush used for a rotating electric machine or the like.

  The electrical loss of an electric brush used for a rotating electrical machine greatly affects the efficiency of the entire rotating electrical machine. For this reason, in a rotating electrical machine that requires high output and high efficiency, it is desirable that the electrical loss of the electric brush is as low as possible.

  As a means for reducing the electrical loss of the electrobrush, it is effective to increase the metal content in the electrobrush and lower the resistivity of the electrobrush body. However, since the electrobrush is a sliding material, increasing the content of a metal with poor lubricity increases the wear rate (sliding characteristics deteriorate), resulting in a problem that the life of the rotating electrical machine is shortened. That is, the conventional electrobrushes have a single layer (single layer) structure as shown in Patent Documents 1 and 2, etc., and thus there is a problem that the wear rate increases when the electrical loss is reduced.

Japanese Utility Model Publication No. 57-027867 JP 57-211954 A

  As a means for satisfying the contradictory required characteristics of reduction of electrical loss and reduction of wear rate, as shown in Patent Document 3, an electric brush is composed of a plurality of layers having different electrical resistances between a high resistance layer and a low resistance layer. The flow performance is improved by reducing the amount of sparks generated, the wear rate is reduced without increasing the contact voltage drop with the commutator, or the electric brush is made to be a high resistance layer as disclosed in Patent Document 4. And the low resistance layer, and the lead wire is embedded in the low resistance layer without touching the high resistance layer, reducing the electrical loss of the electric brush. There are ways to reduce the increase.

JP 09-049478 A JP-T 04-500580

However, in the method as described above, the electrical loss reduction of the electric brush after being left in a high-temperature and high-humidity atmosphere is essentially unchanged in that it is restricted by the balance with the sliding characteristics. .
Therefore, the present inventors have applied for the electrobrush shown in Patent Document 5 as an alternative to the above, but have not yet been satisfied.
Japanese Patent Application No. 2004-116693

  The present invention provides an electric brush that can reduce electrical loss after being left in a high-temperature and high-humidity atmosphere without impairing sliding characteristics, and particularly reduce the wear rate without increasing the voltage drop in the lead wire embedded portion. Is.

The present invention has a two-layer structure in which the sliding surface is a high-resistance layer and a low-resistance layer, or a three-layer structure in which the sliding surface is a high-resistance layer and a medium-resistance layer and the upper portion is a low-resistance layer. The present invention relates to an electric brush in which a lead wire is inserted into a lead wire insertion hole formed in an upper part on the opposite side, and a metal layer or an alloy layer is formed on a peripheral wall surface of the lead wire insertion hole.
The present invention also relates to an electric brush in which a metal layer or an alloy layer is formed by plating and / or spraying.
The present invention also relates to an electric brush in which the metal layer or the alloy layer is a silver layer or a silver alloy layer.
Furthermore, the present invention relates to an electric brush in which the upper surface of the lead wire insertion hole after the lead wire is inserted is coated with a resin.

  The electric brush according to the present invention can reduce electrical loss after being left in a high-temperature and high-humidity atmosphere without impairing sliding characteristics, and in particular, can reduce the wear rate without increasing the voltage drop in the lead wire embedded portion. It is very suitable industrially.

  The electroprinter according to the present invention has a two-layer structure in which the sliding surface is a high-resistance layer and a low-resistance layer or a three-layer structure in which the sliding surface is a high-resistance layer and a medium-resistance layer and the upper portion is a low-resistance layer. A lead wire is inserted into the lead wire insertion hole formed on the upper side opposite to the moving surface, a metal layer or an alloy layer is formed on the peripheral wall surface of the lead wire insertion hole, and a lead wire is further inserted into the lead wire insertion hole. After that, it is composed of one filled with silver-plated copper powder and press-bonded. The resistivity in each layer is not limited as long as the relationship of high resistance layer> low resistance layer or high resistance layer> medium resistance layer> low resistance layer is satisfied, but satisfies the relationship of these resistivity. In the case of a two-layer structure of a high resistance layer and a low resistance layer, for example, the resistivity of the high resistance layer is preferably about 2 to 20 times that of the low resistance layer, more preferably about 4 to 16 times, About 12 times is more preferable.

  In the case of a three-layer structure having a high resistance layer and a medium resistance layer and the upper portion is a low resistance layer, for example, the resistivity of the high resistance layer is preferably about 2 to 20 times that of the medium resistance layer, and about 4 to 16 times. Is more preferable, and about 8 to 12 times is more preferable. The resistivity of the low resistance layer is preferably 2/3 or less, more preferably 1/2 or less, and further preferably 1/3 or less of the resistivity of the medium resistance layer.

  The resistivity is set in accordance with the required characteristics of the rotating electrical machine to be used, but generally has a value of about 0.1 to 30 μΩ · m. The resistivity of each of these layers is appropriately selected by adjusting the amount of metal contained in an electroprinter mainly composed of graphite. Examples of the metal contained in the electroprinter include copper and silver powders.

In the present invention, the metal layer or the alloy layer formed on the peripheral wall surface of the lead wire insertion hole is not particularly limited with respect to the formation method, but is preferably formed by plating and / or spraying. Silver is preferably used as the metal forming the metal layer, while an alloy of silver and copper is preferably used as the alloy forming the alloy layer.
In the present invention, the upper surface of the lead wire insertion hole after the lead wire is inserted is preferably covered with a resin. Although there is no restriction | limiting in particular about the kind of resin to coat | cover, It is preferable to use thermosetting resins, such as a phenol resin and an epoxy resin.

Embodiments of the present invention will be described below with reference to the drawings.
Example 1
80 parts by weight of natural graphite having an average particle size of 50 μm (trade name CB-150, manufactured by Nippon Graphite Industry Co., Ltd.) and 20 parts by weight of a resol type phenol resin (trade name VP11N, manufactured by Hitachi Chemical Co., Ltd.) were kneaded. Thereafter, it was dried at 65 ° C. for 16 hours and then pulverized to obtain a resin-treated graphite powder having an average particle size of 150 μm.

  Next, 45 parts by weight of this resin-treated graphite powder and 55 parts by weight of electrolytic copper powder having an average particle size of 35 μm (trade name CE-25, manufactured by Fukuda Metal Foil Industry Co., Ltd.) are mixed to prepare a powder for a low resistance layer. Got the body. On the other hand, 65 parts by weight of the resin-treated graphite powder obtained above and 35 parts by weight of the electrolytic copper powder used above were mixed to obtain a powder for a high resistance layer.

  Each of the powders obtained above was separately filled into predetermined positions of the mold, integrally molded with a molding press at a pressure of 392 MPa, and then heated to 700 ° C. in a reducing atmosphere in 3 hours. Was sintered for 1 hour and then machined into a predetermined shape to obtain a molded body in which the high resistance layer 1, the low resistance layer 2 and the lead wire insertion hole 3 shown in FIG. 1 were formed.

Next, after silver plating is performed on the peripheral wall surface of the lead wire insertion hole 3 to form a silver plating layer 5, the lead wire 4 is inserted into the lead wire insertion hole 3, and silver plated copper powder is further formed around the lead wire. 6 was filled, and the lead wire 4 was fixed by pressurizing silver-plated copper powder by a stunning operation after filling. Thereafter, the upper surface of the lead wire insertion hole 3 was covered with a resol type phenol resin (trade name VP11N, manufactured by Hitachi Chemical Co., Ltd.) 7 to obtain an electroprinter having a size of 16 × 7 × 15 mm.
When the resistivity of the obtained electroprinter was measured, the high resistance layer 1 was 3.5 μΩ · m and the low resistance layer 2 was 0.2 μΩ · m.

  The resistivity is measured by molding and sintering each powder alone under the same conditions as described above, then machining to produce a test piece having a size of 5 × 5 × 20 mm, and 1A in the direction of 20 mm. The voltage drop between 10 mm when the current was passed was measured and calculated by the following formula. Here, in the test specimen for measurement, the 20 mm direction was set to the direction perpendicular to the molding pressure.

Comparative Example 1
The lead wire 4 is inserted into the lead wire insertion hole without silver plating on the peripheral wall surface of the lead wire insertion hole 3 of the molded body obtained in Example 1, and the same steps as those in Example 1 are performed. An electrobrush with the same shape as the above was obtained. When the resistivity of the obtained electroprinter was measured, the high resistance layer 1 was 3.5 μΩ · m and the low resistance layer 2 was 0.3 μΩ · m.

  Next, the voltage drop value of the lead wire embedded portion immediately after production of the electric brush obtained in Example 1 and the electric brush obtained in Comparative Example 1 (at 0 hour), a temperature of 80 ° C., and a humidity of 90% were 250. The change with time in the voltage drop value of the lead wire embedded portion after the time was examined. The result is shown in FIG. 3, and the value at 0 hours in FIG. 3 is a value immediately after the production. Note that the voltage drop value of the lead wire embedded portion is a value obtained by measuring the voltage drop between CD when a current of 200 A is passed between AB as shown in FIG.

  As shown in FIG. 3, it is clear that the voltage drop value of the lead wire insertion portion of Example 1 according to the present invention is about 26% lower than that of Comparative Example 1. is there. In addition, since the electroprinter of Example 1 and the electrobrush of Comparative Example 1 have the same sliding portion component, there is no difference in the sliding characteristics. Thus, the electric brush of Example 1 is the same as that of Comparative Example 1. On the other hand, it is clear that the electrical loss after being left in a high temperature and high humidity atmosphere is reduced without impairing the sliding characteristics.

It is sectional drawing of the molded object which formed the lead wire insertion hole. 1 is a cross-sectional view of an electroprinter according to an embodiment of the present invention. It is a graph which shows the relationship between leaving time and the voltage drop of a lead wire embedding part. It is the schematic which shows the measuring method of the voltage drop of a lead wire embedding part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High resistance layer 2 Low resistance layer 3 Lead wire insertion hole 4 Lead wire 5 Silver plating layer 6 Silver plating copper powder 7 Resol type phenol resin

Claims (4)

  The sliding surface has a two-layer structure with a high resistance layer and a low resistance layer, or the sliding surface has a three-layer structure with a high resistance layer and a medium resistance layer, and the upper portion has a low resistance layer, and the upper portion on the opposite side of the sliding surface An electroprinter in which a lead wire is inserted into a lead wire insertion hole formed in the above, wherein a metal layer or an alloy layer is formed on a peripheral wall surface of the lead wire insertion hole.   The electric brush according to claim 1, wherein the metal layer or the alloy layer is formed by plating and / or spraying.   The electric brush according to claim 1, wherein the metal layer or the alloy layer is a silver layer or a silver alloy layer. The electric brush according to claim 1, 2 or 3, wherein the upper surface of the lead wire insertion hole after the lead wire is inserted is coated with a resin.

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