JP2001313138A - Brush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide at lower cost a brush of which the connection resistance of a lead wire is low and stable, although a lead wire is inserted into the brush body from the low conductive member side. SOLUTION: The brush comprises a brush body 10 which is composed of a low conductive member 1 and a high conductive member 2 sintered in one body and a lead wire 3 of which one end 31 is embedded in the high conductive member 2 of the brush body 10 from the side where the low conductive member 1 is situated. The low conductive member 1 is made of thin plate form and joined on the surface portion 21 on the sliding contacting side 11 of the side surface of the high conductive member 2. On the other hand, the lead wire 3 is embedded in the surface portion 22 of the high conductive member where the low conductive member 1 is not connected. As the lead wire is embedded only in the high conductive member 2, the connection resistance is low and its fluctuation is small. As the brush body holding the lead wire can be sintered after pressing in one punch, the brush can be manufactured at low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a brush that slides on a commutator of a DC rotating electric machine such as a DC motor or a DC generator.

[0002]

2. Description of the Related Art As a conventional technology, Japanese Patent Application Laid-Open No. 9-49478 discloses a multilayer brush in which a plurality of different types of brush materials having different electric conductivity are laminated. In the brush body described in the embodiment of the publication, a thick high-conductivity member and a thin low-conductivity member are joined and integrally formed.

[0003] The publication does not mention attachment of a lead wire to be connected to the brush body, but when the lead wire is inserted from the side of the highly conductive member into the brush body, the connection resistance is low and good. Connection characteristics can be obtained. However, when a lead wire is inserted into the brush main body from the side of the low conductive member, the connection resistance between the two becomes high, which causes inconvenience. That is, as shown in FIG. 7, since the lead wire 103 inserted into the brush main body 100 from the side of the low conductive member 101 is in contact with the low conductive member 101, the connection resistance increases at this portion. However, the efficiency of a DC rotating electric machine equipped with such a brush decreases, and its performance decreases. In addition, Joule heat generated by the connection resistance may cause overheating.

(Improved technology) In order to avoid such inconvenience, as shown in FIG. 8, the lead wire 103 is inserted deeper into the brush body 100 to reach the highly conductive member 102. However, when the lead wire 103 is inserted, the low conductive member 101 is stuck around. Then, the connection resistance also becomes large at that portion, and some of the above-mentioned inconveniences occur. In addition, the low conductive member 10
Due to the degree of clinging of 1, the connection resistance varies, and as a result, there is also a disadvantage that stable performance of the DC rotating electric machine cannot be obtained. The case where the lead wire 103 is inserted into the brush main body 100 from the side of the low conductive member 101 in this way remains unavoidable in the layout of the lead wire 103.

[0005] (Prior art) [0005] In order to prevent the connection resistance from becoming too large even in such a case, there is a brush disclosed in Japanese Patent Application Laid-Open No. Hei 2-86081 and a method of manufacturing the brush. . That is, the gazette states that
There is disclosed a brush in which only a portion where a lead wire is inserted does not have a low conductive member, and the portion is covered with a high conductive member in a column shape (a column shape or a prism shape). According to this conventional technique, the lead wire does not touch the low-conductive member at all, and is buried only in the high-conductive member, so that the lead wire is inserted into the brush body from the side of the low-conductive member, This has the effect that the connection resistance of the lead wire does not increase.

[0006]

However, according to the prior art, the high-conductivity member must be formed in a columnar shape by partially removing the low-conductivity member. In the process of forming the brush body, the powder material must be compacted twice. as a result,
It is unavoidable that the manufacturing process becomes complicated, the number of steps increases, and the cost increases significantly.

Accordingly, the present invention is to provide a brush at a lower cost, in which a lead wire is inserted into the brush body from the side of the low conductive member and the connection resistance of the lead wire is stable without being increased. Issues to be solved.

[0008]

In order to solve the above problems, the inventors have invented the following means.

(First Means) A first means of the present invention is a brush according to the first aspect. That is, the brush of this means is
It comprises a brush body in which a high conductive member and a low conductive member are joined to each other, and a lead wire having one end embedded in the brush body, and has the following structural features. First, the low-conductivity member has a thin plate shape and is joined to the surface of the high-conductivity member on the side of the sliding contact surface. Next, the lead wire is embedded in the surface of the side of the high conductivity member opposite to the sliding contact surface, to which the low conductivity member is not connected.

[0010] Here, the low conductive member is assumed to be a thin plate, but it is sufficient if the low conductive member has a plate shape or a layer shape which is relatively thin compared to the thickness of the brush. It does not have to be constant. It is desirable that the low-conductivity member covers one surface of the high-conductivity member over the entire width of the brush body, but this is not always necessary.

Further, the low conductive member may be present on one surface of the brush body from a sliding contact surface side in sliding contact with a commutator of the rotating electric machine, at least to a portion corresponding to a maximum wear allowance of the brush body. Desirable, but not limiting. Conversely, even if the low conductive member slightly touches the embedded lead wire, it is within the scope of the present means.

Although the lead wire is embedded in the surface of the brush body opposite to the sliding surface, the embedding range of the lead wire is not limited to the surface portion of the brush body. It may be buried quite deeply. Also, even if it is on the side opposite to the sliding contact surface, the lead wire does not necessarily need to be embedded at the end (opposite end) opposite to the sliding contact surface, but may be embedded to some extent near the opposite end. That's fine.

In this means, the lead wire is buried only in the high conductive member and not in the low conductive member. Therefore, the lead wire is inserted into the brush body from the side of the low conductive member. However, the connection resistance of the lead wire does not increase. In addition, the surface portion of the high conductive member in which one end of the lead wire is buried is not formed in a columnar shape and is surrounded by the low conductive member. Only the side is covered with a thin plate-like low conductive member. Therefore, the connection resistance of the lead wire is not only lower than that of the conventional technology, but also has less variation and maintains a more stable value than that of the conventional technology.

Therefore, according to the brush of the present invention, while the lead wire is buried in the brush body from the side where the low conductive member is provided, the connection resistance of the lead wire is lower than in the prior art, This has the effect of reducing the variation of. As a result, the brush of the present means has an effect that generation of Joule heat is further reduced, and a problem due to overheating is hardly caused. In addition, there is an effect that the performance of the rotating electric machine employing the brush of the present means is improved, and the variation in the performance of the rotating electric machine is reduced.

[0015] In addition, as described in the second to fifth means, the brush of the present means can be easily manufactured by a simpler manufacturing process than the conventional technique, so that the manufacturing cost is reduced and the brush is reduced compared to the conventional technique. There is also an effect that it can be provided at low cost.

Also, unlike the conventional manufacturing process in which a low-conductivity member and a high-conductivity member are compacted in two steps, the low-conductivity member and the high-conductivity member are compacted together by a single punch. You can take steps. As a result, the low-conductivity member and the high-conductivity member are more firmly joined to each other, so that peeling is less likely to occur between them, and the effect of improving the reliability of the brush is obtained.

(Second Means) A second means of the present invention is a brush according to the second aspect. That is, the brush body is filled with a highly conductive powder in a female mold with a predetermined height difference on the surface, and a low conductive powder is roughly plate-shaped on a lower portion of the surface of the highly conductive powder. , And then both are compacted and sintered.

According to this means, in the manufacturing process, there is only one step of compacting the material powder forming the brush main body, so that the manufacturing process is simplified as compared with the conventional technique which requires two compacting steps, and the man-hour is reduced. Manufacturing costs are reduced. As a result, there is an effect that the brush of the present means is less expensive than the brush manufactured by the manufacturing method of the prior art.

Therefore, according to this means, the effect of the first means can be obtained, and the brush described in the first means can be more specifically specified by the manufacturing process.

(Third Means) A third means of the present invention is a brush according to the third aspect. That is, the highly conductive powder is once flatly filled in the female mold, and then the surface portion is formed halfway from one end to the other end to form a step.

In this means, in forming the step on the surface of the highly conductive member in the second means described above, the highly conductive powder is once filled into the female mold flat as described above, The surface portion is moved halfway from one end to the other end. Therefore, by attaching the movable piece to the female mold as described later in the section of the first embodiment, or by inserting the movable piece from above the female mold, the movable piece can be relatively easily attached to the surface of the highly conductive powder. A step can be formed.

Therefore, according to this means, in addition to the effect of the above-described second means, there is an effect that a step can be easily formed on the surface portion of the highly conductive powder.

(Fourth Means) A fourth means of the present invention is the brush according to the fourth aspect. That is, the highly conductive powder is once filled flat in the female mold, and then is further filled to cover a part of the surface, so that the surface is formed with a step.

According to this means, in forming the step on the surface of the highly conductive member in the second means described above, the highly conductive powder is once filled into the female mold flat as described above. Thereafter, the surface of the high conductivity powder is further filled with the high conductivity powder so as to cover a part of the surface, and the surface of the high conductivity powder is formed with a step. Therefore, a step can be formed relatively easily on the surface portion of the highly conductive powder, as will be described later in the description of the modification of the first embodiment.

Therefore, according to this means, in addition to the effect of the above-described second means, there is an effect that a step can be easily formed on the surface portion of the highly conductive powder.

(Fifth Means) A fifth means of the present invention is a brush according to the fifth aspect. That is, the brush body covers the lower end of the female mold from one end to the middle part, fills the low conductive powder with a predetermined thickness, fills the female mold with the high conductive powder from above, and then combines the two. It is compacted and sintered.

In this means, as in the above-mentioned second means, since there is only one compacting step, the manufacturing process is simpler than in the prior art in which the compacting step is required twice, and the man-hour is reduced. Cost is reduced. Moreover, the aforementioned second
Unlike the means, since the low conductive powder is first filled into a predetermined range of the female mold and then the high conductive powder is filled into the female mold,
A step is naturally formed on the downward surface of the highly conductive powder. As a result, there is an effect that the brush of the present means is not only less expensive than the brush manufactured by the conventional manufacturing method, but also more inexpensive than the brush of the aforementioned second means.

Therefore, according to this means, not only the effect of the above-described first means can be obtained, but also the second technique as well as the conventional technique can be obtained.
There is an effect that the brush of the first means can be manufactured at a lower cost than the means.

(Sixth Means) A sixth means of the present invention is the brush according to the sixth aspect. That is, at least a part of the entire circumference of the lead wire is buried in a surface portion of the side surface of the high conductivity member opposite to the sliding contact surface, to which the low conductivity member is not connected.

The present means is equivalent to the above-described first means, in the case where all of the surface portions in which the lead wires are embedded in the brush main body are the surface portions to which the low conductive member is not connected. However, this means differs from the first means described above in that the entire periphery of the lead wire is not surrounded by the highly conductive member, and only a part of the lead wire is surrounded by the highly conductive member. Also includes configuration. In such a configuration,
The portion of the lead wire surrounded by the highly conductive member has an order of magnitude lower resistance than the portion surrounded by the low conductive member, so that considerably good conductivity can be obtained. Then, even if good conductivity is not obtained as much as the first means, a conductivity close to that is obtained, so that an effect equivalent to the first means is obtained. In addition, since the limitation on the formation range of the plate-shaped low-conductive member is less strict than that of the first means, there is an effect that the tolerance is increased in the manufacturing process and the manufacturing can be performed at lower cost.

Therefore, according to the present means, the same effect as or equivalent to that of the above-described first means can be obtained, and at the same time, the effect of being able to manufacture at lower cost is obtained.

It should be noted that a limitation corresponding to the second means to the fifth means with respect to the first means can be added to this means, and the same operation and effect can be obtained.

(Seventh Means) According to a seventh aspect of the present invention, there is provided a brush having a high-conductivity portion having a low resistivity and a low-conductivity portion having a high resistivity, wherein a boundary between the two portions is a sliding contact surface. A brush body including a brush body that is exposed to the outside and a lead wire having a tip portion embedded in the base of the brush body, wherein the brush body includes the low resistivity powder for forming the high conductive portion and the low resistivity powder for forming the low conductive portion. And a powder compact obtained by simultaneously compression-molding the high resistivity powder.

According to this configuration, the low conductive member (low conductive portion)
Are sequentially deposited in the laminating direction after the high-resistivity powder for forming a high-conductivity member and the low-resistivity powder for forming the high-conductivity member (high-conductivity part) are compression-molded at the same time. Compared to molding or molding one and then depositing and molding the other again, low resistivity powder at the boundary between both members due to thermal or mechanical energy during simultaneous molding High resistivity powder mixes with it, producing an intermediate composition at the boundary. As a result, the occurrence of cracks along the boundary due to the thermal cycle acting on the brush can be satisfactorily suppressed.

(Eighth Means) A brush according to a seventh aspect of the present invention has a high-conductivity portion having a low resistivity and a low-conductivity portion having a high resistivity, and a boundary between the two portions is a sliding contact surface. A brush body including a brush body that is exposed to the outside and a lead wire having a tip portion embedded in the base of the brush body, wherein the brush body includes the low resistivity powder for forming the high conductive portion and the low resistivity powder for forming the low conductive portion. A powder compact obtained by compression-molding a high-resistivity powder of the present invention, wherein the powder compact has a boundary portion filled between the low-resistivity powder and the high-resistivity powder. It is characterized by being formed by molding an intermediate resistivity powder for forming a part.

According to this structure, since the intermediate resistivity powder for forming the boundary portion is filled between the low resistivity powder for forming the high conductive portion and the high resistivity powder for forming the low conductive portion, the current is interrupted. Due to the difference in the coefficient of thermal expansion between the low conductive portion and the high conductive portion, cracks and macrocracks along the boundary can be satisfactorily suppressed.

[0037] In a preferred aspect of the brush having this configuration, the intermediate resistivity powder has a resistivity that increases continuously or stepwise from the low resistivity powder side to the high resistivity powder side. According to this aspect, since the composition of the boundary portion is changed continuously or stepwise in the thickness direction, further prevention of cracking can be realized.

(Ninth Means) A brush having a ninth configuration according to the present invention has a high-conductivity portion having a low resistivity and a low-conductivity portion having a high resistivity, and a boundary between the two portions is a sliding contact surface. A brush body including a brush body that is exposed to the outside and a lead wire having a tip portion embedded in the base of the brush body, wherein the brush body includes the low resistivity powder for forming the high conductive portion and the low resistivity powder for forming the low conductive portion. The vibration energy is applied after the high resistivity powder is sequentially filled in the mold and before the compression molding.

According to this configuration, after the low-resistivity powder and the high-resistivity powder are filled into a mold to form a laminated powder, the kinetic energy is individually applied to each powder of the laminated powder by, for example, shaking the mold. give. As a result, the low-resistivity powder and the high-resistivity powder adjacent to each other at the boundary portion are mixed, so that the boundary portion collapses to form an intermediate resistivity powder layer. Thereafter, if compression molding is performed, cracking at the boundary can be satisfactorily suppressed.

(Tenth Means) A brush having a tenth structure according to the present invention has a high-conductivity portion having a low resistivity and a low-conductivity portion having a high resistivity, and a boundary between the two portions is in sliding contact. In a brush including a brush body exposed to a surface and a lead wire having a tip portion embedded at the base of the brush body from the low conductive portion side, the low conductive portion is closer to the lead wire than other portions. Are also formed to be thin in the length direction of the embedded portion of the lead wire.

That is, in the present configuration, in the brushes of the first to sixth configurations, a layer of a low conductive portion in contact with the brush is provided near the brush. However, the thickness of the layer of the low conductive portion in the vicinity of the brush (the length direction of the lead wire) is made smaller than the thickness of the layer of the low conductive portion in other portions.
Compared to the conventional type in which the low conductive portion has a uniform layer thickness, the contact resistance between the lead wire and the brush body is reduced, and the ratio of the low conductive portion in the area near the brush where current is locally concentrated is further reduced. Is increased, so that resistance loss and heat generation in this region can also be reduced.

[0042]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the brush of the present invention will be clearly and fully described in the following examples so that those skilled in the art can understand the present invention.

Embodiment 1 (Structure of Embodiment 1) A brush according to Embodiment 1 of the present invention is a component constituting a DC rotating electric machine (not shown) and is in sliding contact with a commutator (not shown). As shown in FIG. 1, the brush of the present embodiment includes a block-shaped brush body 10 and a lead wire 3 having one end 31 embedded in the brush body 10.

That is, the brush body 10 includes the high conductive member 2 and the low conductive member 1 integrally joined to the high conductive member 2. Here, the highly conductive member 2 is a member having a high electrical conductivity made of a sintered alloy containing copper as a main component, and may be called a low resistivity member. On the other hand, the low conductive member 1 is made of a sintered material containing graphite as a main component and additive particles such as a binder and has a low electric conductivity, and may be called a high resistivity member.

The commutator (not shown) of the brush body 10
The sliding contact surface 11 slidably contacting is formed by both end surfaces of the high conductive member 2 and the low conductive member 1. Conversely, the base end surface 12 urged by a spring (not shown) is formed facing the sliding contact surface 11, and is formed only from the end surface of the highly conductive member 2.

The low conductive member 1 is in the form of a thin plate having a substantially constant thickness, and is joined to the surface portion 21 of the side surface of the high conductive member 2 on the sliding contact surface 11 side. On the other hand, the lead wire 3 is a surface portion 2 of the side of the high conductivity member 2 opposite to the sliding contact surface 12 to which the low conductivity member 1 is not connected.
2 buried. The low conductive member is the brush body 10
High conductive member 2 over the entire width (in the depth direction of FIG. 1)
Covers one surface. In addition, the low conductive member 1
One of the surfaces of the brush body 10 extends from a side of the sliding contact surface 11 that is in sliding contact with a commutator (not shown) of the rotating electric machine to at least a portion that slightly exceeds the maximum wear allowance of the brush body. The low conductive member 1 is joined to the high conductive member 2 at a predetermined distance from the lead wire 10 embedded in the brush body 10.

The lead wire 3 is a strand (twisted wire) formed by twisting a large number of fine copper wires, and is commonly used as a pigtail. One end 31 of the lead wire 3 buried in the highly conductive member 2 of the brush body 10 is formed by cutting off a tip end surface, and is firmly joined to the highly conductive member 2 and fixed to the brush body 10. I have. One end 31 of the lead wire 3 has a predetermined depth from the surface portion 22 of the brush body 10 opposite to the sliding contact surface 11 at a predetermined depth.
Buried in The lead wire 3 is embedded in the highly conductive member 2 at a predetermined distance from the base end face 12 even on the side opposite to the sliding contact surface 11.

(Effects of Embodiment 1) The brush of this embodiment has the above-described structure, and thus exhibits the following effects.

First, since the lead wire 3 is embedded only in the high conductive member 2 and not embedded in the low conductive member 1, the lead wire 3 is connected to the brush body 10 from the side where the low conductive member 1 is located. The connection resistance of the lead wire 3 does not increase while the wire 3 is inserted. Moreover, the surface portion 22 of the high conductive member 2 in which the one end 31 of the lead wire 3 is buried is not necessarily formed in a columnar shape and surrounded by the low conductive member 1 as in the related art. That is, of the one surface of the highly conductive member 2 on which the lead wire 3 is inserted, the sliding contact surface 11
Only the side is covered with the thin low-conductivity member 1. Therefore, the connection resistance of the lead wire 3 is not only lower than that of the above-described conventional technology, but also has less variation than that of the conventional technology, and maintains a more stable value.

Therefore, according to the brush of this embodiment,
While the lead wire 3 is buried in the brush body 10 from the side where the low conductive member 1 is provided, there is an effect that the connection resistance of the lead wire 3 is lower than in the related art and the variation in the resistance value is smaller. . As a result, the brush according to the present embodiment has an effect that generation of Joule heat is further reduced, and a problem due to overheating is hardly caused. In addition, there is an effect that the performance of the rotating electric machine employing the brush of the present means is improved, and the variation in the performance of the rotating electric machine is reduced.

Second, as will be described in the next section, the brush of the present embodiment can be easily manufactured by a simpler manufacturing process than in the prior art, so that the manufacturing cost is reduced and the brush can be provided at a lower cost than in the prior art. There is also an effect that it becomes.

Third, unlike the conventional manufacturing process in which the low-conductivity member and the high-conductivity member are compacted in two steps, the low-conductivity member 1 and the high-conductivity member 2 are joined together by one punch. The brush of this embodiment is manufactured in a manufacturing process in which the brush is compacted. As a result, the low-conductivity member 1 and the high-conductivity member 2 are more firmly joined to each other.
The brush of the present embodiment also has the effect of improving its reliability.

(Manufacturing process of Embodiment 1) As shown in FIGS. 2A to 2F, the brush of this embodiment
The high-conductivity powder 2 ', which is a material of the above, and the low-conductivity powder 1', which is a material of the low-conductivity member 1, are formed by one punch (a single compacting step). After that, the molded product
The one end 31 of the lead wire 3 is fired in a buried state, and the brush body 10 is formed as a sintered body. That is, the brush body 10 contains the highly conductive powder 2 ′ in the female mold 4.
Is filled in the surfaces 21 ′ and 22 ′ with a step of a predetermined height, and the lower portion 2 of this surface of the highly conductive powder 2 ′ is filled.
After filling low conductive powder 1 'in a plate shape into 1', both 1 'and 2' are compacted and sintered.

More specifically, as shown in FIG. 2B, the highly conductive powder 2 ′ is once filled flat into the recess 40 of the female mold 4. Then, FIG.
As shown in (d), when the movable piece 41 protrudes from one end of the female mold 4 with a predetermined stroke and then returns, the surface portion of the highly conductive powder 2 ′ is moved halfway from one end to the other end. , The surfaces 21 ′ and 22 ′ are formed with steps. After the movable piece 41 closes the surface 21 ',
Step 22 may be formed by refilling 22 'again. Next, as shown in FIG. 2 (e), the lower surface 21 ′ of the high conductive powder 2 ′ is filled with the low conductive powder 1 ′ in a stepped thickness, and the low conductive powder 1 ′ is filled. And the surface of the highly conductive powder 2 'is substantially flat at substantially the same height. Thereafter, the male mold 5 holding the one end 31 of the lead wire 3 protruded and fitted into the female mold 4 from above is pushed in, and while the one end 31 of the lead wire 3 is pushed into the highly conductive powder 2 ′, Conductive powder 1 '
And the highly conductive powder 2 'are pressed together.

In this way, the high conductive powder 2 'and the low conductive powder 1' are integrally formed by one punch to form a molded body, and one end 31 of the lead wire 3 is fixed in the compacted high conductive powder 2 '. Is done. Thereafter, the molded product is taken out from the female mold 4 and fired in a heating furnace with the one end 31 of the lead wire 3 buried therein, thereby constituting the brush body 10 as a sintered body.

In the above manufacturing process, the brush body 10
There is only one step of compacting the material powders 1 ', 2' forming Therefore, in this embodiment, the manufacturing process is simplified, the number of steps is reduced, and the manufacturing cost is reduced, as compared with the conventional technique that requires two compacting steps. As a result, there is an effect that the brush of the present embodiment is less expensive than the brush manufactured by the conventional manufacturing method. Further, for the same reason, the bonding between the high conductive powder 2 'and the low conductive powder 1' is strengthened, and the low conductive member 1 is hardly peeled off from the high conductive member in a brush as a product. There is an effect that the above reliability is improved.

(Modification 1 of Embodiment 1) As a modification 1 of this embodiment, as shown in FIGS. 3A to 3D, it is possible to implement a brush whose manufacturing process is slightly different from that of Embodiment 1. is there. That is, in the manufacturing process of the brush according to the present modification, the highly conductive powder 2 ′ is once filled flat in the female mold 4 as shown in FIG. As described above, a part of the surface is further filled to fill the surface, and the surface is formed with a step. The subsequent steps are shown in FIGS.
As shown in (d), this is the same as the manufacturing process of the first embodiment.

In the manufacturing process of this modified embodiment, when forming a step on the surface of the highly conductive member 2, the highly conductive powder 2 ′ is once filled into the female mold 4 flat as described above. Thereafter, a portion of the surface is covered with the highly conductive powder 2 ′ to further fill the surface 21 ′ of the highly conductive powder.
22 'is formed with a step. Therefore, the movable piece 41 (see FIG. 2) is not required for the female mold 4, the configuration of the female mold 4 is simplified, and the production of the highly conductive powder 2 ′ is slightly easier than the manufacturing process in the first embodiment. Steps can be formed on the surfaces 21 'and 22'.

Therefore, according to the brush of this modified embodiment, in addition to the effects of the first embodiment, a step can be formed relatively easily on the surfaces 21 ', 22' of the highly conductive powder 2 '. This has the effect.

In the brush of this modified embodiment, as shown in FIG. 5B, the edge of the high-conductive powder 2 ', which is provided later, is spontaneously collapsed.
The steps 1 'and 22' are not formed in steps but in a slightly rounded slope. Therefore, in the brush as a product, there is also an effect that stress concentration is slightly relieved at corners of the low conductive member 1 and strength is increased.

(Modification 2 of Embodiment 1) As Modification 2 of the present embodiment, part of the entire circumference of the lead wire 3 is located on the side of the side of the highly conductive member 2 opposite to the sliding contact surface 11. It is possible to implement a brush that is buried in the surface portion 22 to which the low-conductivity member 1 is not connected. In other words, in the brush of the present modified embodiment, at least half of the entire circumference of the lead wire 3 is buried in the surface portion 22 having the high conductive member 2, and the other portion of the lead wire 3 is low conductive member 1 is embedded in the brush body 10.

In this modification, the resistance of the part of the lead wire 3 surrounded by the high conductive member 2 is significantly smaller than that of the part surrounded by the low conductive member 1, so Is obtained. Then, even if the conductivity is not as good as that of the brush of the first embodiment, it is possible to obtain a conductivity close to that. Therefore, according to the brush of the present modified embodiment, an effect similar to that of the first embodiment can be obtained. In addition, there is an effect that the tolerance regarding the formation range of the plate-shaped low conductive member 1 is increased, and the manufacturing can be performed at lower cost.

Therefore, according to the present modified embodiment, while obtaining an effect equivalent to or equivalent to that of the first embodiment,
The effect of being able to manufacture at lower cost is also obtained.

Embodiment 2 (Structure and Operation and Effect of Embodiment 2) A brush as Embodiment 2 of the present invention is substantially the same as Embodiment 1 described above, as shown in FIG. The configuration is different from that of the first embodiment in the following two points.

First, one end 31 of the lead wire 3 is buried in the highly conductive member 2 much deeper than in the first embodiment.
Therefore, the connection resistance between the lead wire 3 and the highly conductive member 2 is smaller than that in the first embodiment, the resistance loss is further reduced, the overheating becomes difficult, and the rotation using the brush of the present embodiment is performed. This has the effect of improving the performance of an electric machine (not shown).

Secondly, there is no corner at a portion of the thin plate-like low-conductivity member 1 which is in contact with the high-conductivity member 2, and instead, the curved surface R having an appropriate curvature forms the low-conductivity member 1 with the high-conductivity The member 2 is joined to each other. As a result, the concentration of stress such as thermal stress around the curved surface R is greatly reduced, and the brush of the present embodiment has an effect of further improving the strength.

Further, the brush of this embodiment can be manufactured by a simple manufacturing process as described in the next section.
There is an effect that it can be provided even more cheaply.

All of these effects result from the following manufacturing steps.

(Manufacturing Process and Effect of Embodiment 2) FIG.
As shown in (a) to (c), the brush body 10 (see FIG. 4) is filled with the low conductive powder 1 ′ at a predetermined thickness so as to cover from one end to the middle of the bottom surface of the female mold 4. After filling the female mold 4 from above with the highly conductive powder 2 ', the two are compacted and sintered.

That is, first, as shown in FIG.
The low conductive powder 1 'is filled with a predetermined thickness so as to cover from one end of the bottom surface of the female mold 4 to the middle part. The range in which the low conductive powder 1 'is scattered at a constant thickness is a range equal to the maximum brush wear allowance. At this time, the edge of the low conductive powder 1 'in the middle part of the female mold 4 is naturally collapsed by gravity and is formed with a curved surface having an appropriate curvature, and is not formed at a right angle. In addition, when the edge of the low-conductive powder 1 'collapses, the surface (lower surface) of the low-conductive powder 1' extends to a range slightly exceeding the brush wear allowance. However, an appropriate clearance is formed between the low conductive powder 1 'and the lead wire 3 so that the low conductive powder 1' does not directly contact the lead wire 3.

Next, as shown in FIG. 5 (b), one end 31 of the lead wire 3 which protrudes considerably from the bottom surface of the female die 4 and is held vertically and the low conductive powder 1 'are covered with the female die 4. The mold 4 is filled with the highly conductive powder 2 ′. At this time, unlike the case where the lead wire 3 is pushed into the already filled highly conductive powder 2 ′ as in the first embodiment, the one end 31 of the lead wire 3 is reversed.
Is filled with a highly conductive powder 2 ′. Therefore, even if one end 31 of the lead wire 3 protrudes longer than in the first embodiment, the highly conductive powder 2 ′ is scattered from above,
The periphery of one end 31 of the lead wire 3 is filled with the highly conductive powder 2 ′ without difficulty. As a result, the highly conductive powder 2 ′
Covers the periphery of one end 31 of the lead wire 3 and the surface of the low conductive powder 1 ′, and the upper surface of the high conductive powder 2 ′ naturally becomes substantially flat.

Finally, as shown in FIG.
Press with the male mold 5 fitted to the low conductive powder 1 '
And the highly conductive powder 2 'is compacted. Thereafter, the molded body is taken out of the female mold 4 and sintered to form the brush (see FIG. 4) of the present embodiment as described above.

In this embodiment, as in the first embodiment and the first modification thereof, the compacting step is performed only once, so that the manufacturing process is simplified as compared with the prior art in which the compacting step is required twice. In addition, the number of steps is reduced and the manufacturing cost is reduced. Moreover, unlike the above-described embodiment 1 and its modification 1, the low-conductivity powder 1 'is first filled into a predetermined range of the female mold 4, and then the high-conductivity powder 2' is filled into the female mold 4. Therefore, a step is naturally formed on the downward surface of the highly conductive powder 2 ′. As a result, the brush of the present embodiment is not only inexpensive than the brush manufactured by the conventional manufacturing method, but also has the effect that the brush is more inexpensive than the brushes of the above-described embodiment 1 and its modification 1. Occurs.

(Modification 1 of Embodiment 2) As a modification 1 of the present embodiment, it is possible to implement a brush having a configuration corresponding to the modification 2 of the embodiment 1 with respect to the present embodiment. . According to this modification, the same operation and effect as those of Modification 2 of Embodiment 1 can be obtained.

(Other effects of the above embodiment) In each of the above-described embodiments, the high resistivity powder for forming the low conductive member (low conductive portion) 1 and the high conductive member (high conductive portion) 2 are used. After the low resistivity powder to be formed is sequentially deposited in the laminating direction, the powder is simultaneously compression-molded.

In this way, the thermal or mechanical energy at the time of simultaneous molding is smaller than forming them separately or forming one and then depositing and molding the other again. As a result, the low-resistivity powder and the high-resistivity powder mix at the boundary 100 between the two members (see FIG. 6),
Intermediate compositions occur at the boundaries. As a result, the occurrence of cracks along the boundary due to the thermal cycle acting on the brush can be satisfactorily suppressed.

The technique and effect of simultaneously forming a plurality of powder layers having different compositions from each other are not limited to those of the first and second embodiments. It can be applied to all mold brush molding.

(Modification) In Embodiments 1 and 2 described above,
The low conductive member 1 does not cover the entire left side surface of the brush body 10 in FIG.
The middle, left and right directions) are all occupied by the highly conductive members 2.

However, as a modification thereof, even if a layer of the low conductive member 1 thinner than the low conductive member 1 shown in FIG. It is apparent that the contact resistance between the brush body 3 and the brush body 10 can be reduced, and the resistance loss (due to local current concentration) of the brush body 10 near the lead wire 3 can be reduced.

[Embodiment 3] Another embodiment of the brush of the present invention will be described below with reference to FIG.

The brush of this embodiment is composed of a high resistivity powder for forming the low conductive member (low conductive portion) 1 and a low resistivity powder for forming the high conductive member (high conductive portion) 2. After depositing and filling a layer of the intermediate resistivity powder for forming the boundary portion 100 therebetween, they are simultaneously compression-molded.

In this way, the intermediate resistivity powder for forming the boundary portion is filled between the low resistivity powder for forming the high conductive portion and the high resistivity powder for forming the low conductive portion, so Due to the difference in the coefficient of thermal expansion between the low conductive portion and the high conductive portion, cracks and macrocracks along the boundary can be satisfactorily suppressed.

In the preferred embodiment of this embodiment, the composition of the intermediate resistivity powder is changed from the composition of the low resistivity powder to the composition of the high resistivity powder from the low resistivity powder side to the high resistivity powder side. And may be increased continuously or stepwise. For example, a plurality of intermediate resistivity powders each having a slightly different composition may be deposited little by little. With this configuration, the composition of the boundary portion is changed continuously or stepwise in the thickness direction, so that further prevention of cracks can be realized.

[Embodiment 4] Another embodiment of the brush of the present invention will be described below with reference to FIG.

The brush of this embodiment may be subjected to compression molding after the dies 4 and 5 are vibrated by a vibration motor or the like for a predetermined time in the state of FIG. 3D, for example. In this way, the low-conductivity powder 1 'and the high-conductivity powder 2' are mixed at the boundary, so that the boundary becomes an intermediate resistivity powder layer. Thereafter, if compression molding is performed, cracking at the boundary can be satisfactorily suppressed.

The technique and effect of simultaneously forming a plurality of powder layers having different compositions from each other are not limited to those of the first and second embodiments. It can be applied to all mold brush molding.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of a brush as a first embodiment.

FIGS. 2A to 2F are longitudinal sectional views schematically showing respective steps of a manufacturing process of the brush as the first embodiment; FIGS.

FIGS. 3A to 3D are longitudinal sectional views schematically showing each of the assembly steps (a) to (d) showing the steps of manufacturing the brush according to a first modification of the first embodiment; FIGS.

FIG. 4 is a longitudinal sectional view showing a configuration of a brush as a second embodiment.

FIGS. 5A to 5C are longitudinal sectional views schematically showing respective steps of a manufacturing process of a brush as a second embodiment; FIGS.

FIG. 6 is a longitudinal sectional view showing another effect of the brush of the first embodiment.

FIG. 7 is a longitudinal sectional view showing a configuration of a brush according to a conventional technique.

FIG. 8 is a longitudinal sectional view showing a configuration of a brush obtained by improving a conventional technology.

[Explanation of symbols]

 10: Brush body 11: Sliding contact surface 12: Base end surface 1: Low conductive member 2: High conductive member 21: Surface portion (joined with low conductive member) 22: Surface portion (surface opposite to sliding contact surface) 1 ': Low conductive powder 2': High conductive powder 21 ': Surface (low part of surface) 22': Surface (high part of surface) 3: Lead wire (pigtail) 4: Female mold 40: recess 41: movable piece 5: male

Claims (11)

[Claims] 1. A high-conductivity member and a low-conductivity member joined to the high-conductivity member, and the sliding surfaces which are in sliding contact with the commutator are end faces of both the high-conductivity member and the low-conductivity member. And a lead wire having one end embedded in the brush body, wherein the low conductive member has a thin plate shape and slides on a side surface of the high conductive member. The lead wire is buried in a surface portion of the side surface of the high conductivity member opposite to the sliding contact surface, where the low conductivity member is not connected. A brush. 2. The brush body is filled with a highly conductive powder in a female mold at a predetermined height step on a surface thereof, and a low conductive powder is placed on a lower portion of the surface of the highly conductive powder. 2. The brush according to claim 1, wherein after being filled in a substantially plate shape, both are compacted and sintered. 3. The method according to claim 1, wherein the highly conductive powder is once filled flat in the female mold, and then the surface portion is formed halfway from one end to the other end to form the surface with the step. The brush according to claim 2, wherein the brush is applied. 4. The method according to claim 1, wherein the high-conductivity powder is once filled flat in the female mold, and further filled over a part of the surface to form the surface with the step. 2. The brush according to 2. 5. The brush body is filled with a low-conductivity powder at a predetermined thickness so as to cover from one end to an intermediate portion of the bottom of the female mold, and the female mold is filled with a high-conductivity powder from above. rear,
The brush according to claim 1, wherein both are compacted and sintered. 6. A high-conductivity member and a low-conductivity member joined to the high-conductivity member, and the sliding surfaces which are in sliding contact with the commutator are end faces of both the high-conductivity member and the low-conductivity member. And a lead wire having one end embedded in the brush body, wherein the low-conductivity member has a thin plate shape and slides on a side surface of the high-conductivity member. At least a part of the entire circumference of the lead wire is connected to the low conductive member on the side of the side surface of the high conductive member opposite to the sliding contact surface. A brush buried in an uncoated surface portion. 7. A brush body having a low-conductivity high-conductivity part and a high-resistivity low-conductivity part, wherein a boundary between the two parts is exposed to a sliding contact surface, and a tip part of the brush body is A brush having a lead wire embedded in a base, wherein the brush body is a powder obtained by simultaneously compression-molding the low resistivity powder for forming the high conductive portion and the high resistivity powder for forming the low conductive portion. A brush comprising a body compression body. 8. A brush body having a high-conductivity portion having a low resistivity and a low-conductivity portion having a high resistivity, wherein a boundary portion between the two portions is exposed to a sliding contact surface, and a tip portion of the brush body is provided. A brush having a lead wire embedded in a base, wherein the brush body is formed by compression-molding the low resistivity powder for forming the high conductive portion and the high resistivity powder for forming the low conductive portion. The powder compact may be formed by molding an intermediate resistivity powder for forming a boundary filled between the low resistivity powder and the high resistivity powder. A brush characterized by the following: 9. The brush according to claim 8, wherein the intermediate resistivity powder has a resistivity that increases continuously or stepwise from the low resistivity powder side to the high resistivity powder side. brush. 10. A brush body having a low-conductivity high-conductivity portion and a high-resistivity low-conductivity portion, wherein a boundary between the two portions is exposed to a sliding contact surface, and a tip portion of the brush body is provided. In a brush including a lead wire embedded in a base portion, the brush body may be formed by sequentially filling a mold with the low resistivity powder for forming the high conductive portion and the high resistivity powder for forming the low conductive portion. A brush to which vibration energy is applied before compression molding. 11. A brush body having a low-conductivity high-conductivity part and a high-resistivity low-conductivity part, wherein a boundary between the two parts is exposed to a sliding contact surface, and a tip part is the brush body. A brush having a lead wire buried from the low conductive portion side at the base of the brush, wherein the low conductive portion is formed to be thinner in the length direction of the buried portion of the lead wire near the lead wire than other portions. A brush characterized by being made.