JPH0896916A - Electric brush and its manufacture - Google Patents

Abstract

PURPOSE: To provide an electric brush capable of shortening the overall length (in the direction of abrasion) of itself while avoiding the drop of mechanical strength of each part. CONSTITUTION: In a brush consisting of a head 3, which has well conductive metal for its main ingredient, and a body 2, which has graphite for its main ingredient, a pig tail 4 is fixed to the outer face or inside of the head 3 without contacting with the body 2. By doing it this way, since the pig tail 4 is not interposed between the body 2 and the head consisting of heterogeneous material and being different in thermal expansion coefficient, etc., the junction strength between the body 2 and the head 3 can be improved, and also the contact resistance at the junction interface between both and the heat generation or power loss by it can be reduced. Furthermore, since the head 3 of the brush has metil for its main ingredient, the pig tail 4 and the head 3 can be joined with each other easily and strongly without elongating the head of a conventional brush in the direction of abrasion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating machine brush.

[0002]

2. Description of the Related Art Conventionally, as a method of connecting and fixing a brush for feeding an armature coil of a rotating machine and a pigtail for feeding the brush, a tip of the pigtail is put in a hole formed in a side surface of a base end portion of the brush. , A method of hardening with copper powder or the like (powder stopping method) is known. In Japanese Patent Laid-Open No. 52-124107, a lead (pigtail) is brought into contact with the base end face of a green compact for forming a brush, and a conductive supporting member is brought into contact with the base face of the lead and the green compact. Then, in this state, the assembly is sandwiched between the electrodes for sintering and heated and pressed to sinter the green compact and bond the respective members. The support member has a compact made of a pigtail (hereinafter, also referred to as a brush).
It is fixed to the base end face of and the electric resistance between the pigtail and the brush is reduced.

Japanese Unexamined Patent Publication No. 62-171434 discloses that after the pigtail is fixed to the brush by the above-mentioned powder stopping method, conductive paint is applied to the surface of the brush to reduce the contact resistance between the pigtail and the brush. Is disclosed.

[0004]

However, in the method of inserting the tip end of the pigtail into the hole on the side surface of the base end of the brush and hardening with copper powder or the like and the latter publication mentioned above, in order to ensure the strength of the hole in particular, Since it is necessary to dispose the pigtail sufficiently away from the base end surface of the brush, the total length of the brush becomes long, resulting in an increase in the brush storage space and materials, which hinders miniaturization. there were.

On the other hand, according to the former publication, the base end surface of the powder compact (brush) having a relatively high resistance and the support member having a low resistance compress the pigtail, so that the pigtail is joined to the base end surface of the powder compact (brush). Due to the presence of the pigtail, a part of the joint surface of the low-resistance support member, which should be in contact with the brush, cannot contact the brush, resulting in a decrease in the joint strength between the support member and the brush. Further, according to the former publication, the powder compact (brush), the pigtail and the supporting member must be simultaneously pressed, the pigtail cannot be retrofitted, the die structure becomes complicated, and the degree of freedom in the manufacturing process is increased. There was also the problem of being scarce.

The present invention has been made in view of the above problems, and provides an electric brush and its manufacturing method capable of shortening the total brush length (wearing direction) while avoiding a decrease in mechanical strength of each part. Is the purpose.

[0007]

The first structure of the present invention is as follows.
A brush in which a head having a good conductivity metal as a main component and forming a base end is integrated with a body part having graphite as a main component and forming a tip and a center, and the head without contacting the body part An electric brush comprising: a pigtail joined to the outer end surface or the inside of the portion.

A second configuration of the present invention is characterized in that, in the first configuration, the pigtail is fixed to an outer end surface of the head portion of the brush. A third configuration of the present invention is characterized in that, in the first configuration, the pigtail is inserted into a hole of the head portion of the brush. A fourth configuration of the present invention is the first to the above.
In any one of the third configurations, the pigtail further functions as a spring for pressing the brush.

According to a fifth aspect of the present invention, a head having a good conductivity metal as a main component and forming a base end is integrated with a body having graphite as a main component and forming a tip and a center. An electric machine characterized in that a brush is prepared, and the tip end of a pigtail for power feeding is fixed to the outer end surface or inside of the head by welding, caulking, press fitting, powdering, or integral molding without contacting the body. It is a manufacturing method of a brush.

A sixth structure of the present invention is characterized in that, in the fifth structure, the pigtail is formed integrally with the head part together with the body part. In a seventh configuration of the present invention, the tip portion of the pigtail is fitted in a recess or a hole formed in an outer end surface or a side surface of the head unit integrated with the body section in the seventh configuration. After that, they are joined by welding, caulking or powdering.

According to an eighth aspect of the present invention, a brush containing graphite as a main component, the brush is inserted into the inside from a side surface of the head,
In an electric brush with a fixed pigtail,
The cross section of the pigtail in a direction perpendicular to the longitudinal direction of the pigtail has a flat shape in which the width in the wear direction of the brush is compressed.

[0012]

According to the first structure of the present invention,
In a brush including a head mainly composed of a good conductive metal and a body mainly composed of graphite, a pigtail is fixed to the outer end surface or the inside of the head without contacting the body. In this way, the pigtail does not intervene between the body and the head, which are made of different materials such as copper and graphite and have different coefficients of thermal expansion, so that the body and the head are joined together. The strength can be improved, and the contact resistance at the bonding interface between the two and heat generation and power loss due to the contact resistance can be reduced.

Furthermore, since the head of the brush is mainly composed of metal, the pigtail made of a metal having good conductivity and this head can be easily formed by various methods without lengthening the head of the conventional brush in the wear direction. Moreover, they can be strongly bonded and the contact resistance between them can be sufficiently reduced. According to a second configuration of the present invention, in the above first configuration,
Since the pigtail is fixed to the outer end surface of the head of the brush, the pigtail can be easily retrofitted after joining the head and the body, and the joining process between the head and the body can be simplified. The head wear direction length can be shortened, and
The pigtail directly has a body (the main component is graphite)
Since it does not come into contact with, but contacts the body part with a large joint area through the low resistance head, it is possible to reduce the overall internal resistance of the brush.

In the third structure of the present invention, since the pigtail is inserted into the hole of the head of the brush in the above-mentioned first structure, a large joint area can be provided to the body through the low resistance head. It is also possible to reduce the total internal resistance of the brush. Furthermore, since the head is made of metal as a main component and has higher strength than the body, the distance between the pigtail and the base end face of the head can be compressed, and the length in the wear direction of the brush can be shortened. Therefore, the brush can be downsized.

In the fourth structure of the present invention, the pigtail further functions as a spring for pressing the brush in any one of the first to third structures, so that the number of parts is reduced while suppressing an increase in voltage drop. can do. That is, the conventional pigtail, which also serves as a spring for pressing the brush, is merely press-contacted to the base end surface of the brush after the brush has been molded so as to be essentially separable, and a non-negligible contact resistance remains between them. Causes voltage drop and heat generation.

On the other hand, in this structure, since the head of the brush is mainly composed of metal, a strong and simple bonding method peculiar to metal-metal, such as caulking, can be adopted. Even if the pigtail also serves as a spring, the contact resistance between the pigtail and the brush can be favorably reduced. According to a fifth aspect of the present invention, in order to realize the first configuration, the pigtail and the head are joined by welding, caulking, press fitting, powdering, or integral molding.

With this arrangement, the advantages of the first structure can be realized by a simple process. Sixth of the present invention
In the above construction, in addition to the fifth construction, the pigtail is formed integrally with the body together with the head. In this way, the joining process is performed only once and is simple.

A seventh structure of the present invention is, in the fifth structure, further provided with a pigtail in a hole (hole) formed in a concave portion or a side surface formed on the outer end surface of the head integrated with the body portion. After fitting the tip of the, the two are joined by welding or caulking or powdering, so after the body and the head are integrated, the pigtail can be easily retrofitted, and the body and the head can be attached. When heating and pressurizing, the pigtail does not get in the way, the pressurizing device, especially the mold structure thereof can be simplified, and the mounting posture and mounting position of the pigtail are also improved.

According to an eighth aspect of the present invention, when inserting and fixing the pigtail from the side surface of the head of the brush whose main component is graphite, the cross section in the direction perpendicular to the longitudinal direction of the pigtail is the wear direction of the brush. Has a compressed flat shape, the ratio of the effective portion (wearable portion) of the brush can be increased, and the brush can be miniaturized. It should be noted that the pigtail can be flat (for example, a rectangular cross section) only at its tip, or it can be flat over the entire surface, or a plate spring.

[0020]

【Example】

(Embodiment 1) Hereinafter, the present invention will be described with reference to the drawings in which concrete embodiments are described. FIG. 1 is a perspective view showing a state in which an electric brush 1 according to an embodiment of the present invention is assembled to an electric motor. In FIG. 1, the electric brush 1 has a rectangular parallelepiped shape,
A commutator 5 with a spring (not shown)
It is pressed against and arranged.

The electric brush 1 comprises a body portion 2, a head 3 formed integrally with one end surface of the brush 2, and a pigtail 4 which is fitted into and fixed to the inside of the side surface of the head 3. The body portion 2 and the head portion 3 form the brush referred to in the present invention. The body portion 2 has a void portion 23 of a foamed metal (for example, Celmet manufactured by Sumitomo Electric Industries, Ltd.), which is a porous metal body 21 in which metals are three-dimensionally connected, and the treated graphite 2 described later
2, and the head 3 is also formed by compressing and molding a foam metal (for example, Celmet manufactured by Sumitomo Electric Industries, Ltd.) that is the porous metal body 31. The pigtail 4 made of copper wire is fitted and fixed in the pigtail mounting hole 5 of the head 5.

Next, a method of manufacturing the electric brush 1 will be described. Graphite powder (Nippon Graphite: CB150) 95% by weight
And binder (Sumitomo Durres Co., Ltd. Phenol PR217
K) 15% by weight of ethanol was added to and mixed with 100% by weight of a mixture of 5% by weight, ethanol was volatilized to dry the mixture, and then the mixture was ground,
The treated graphite was sized by sieving to prepare a treated graphite. Next, 60% by weight of ethanol was added to this treated graphite and kneaded to prepare paste-like graphite. Then, this paste-like graphite was sprayed onto a Cu foam metal (trade name: Celmet) manufactured by Sumitomo Electric by an air spray gun (manufactured by Iwata: agitator spray gun W-88A-13H2g), graphite was filled in the pores, and Alco was used again. After volatilizing the resin, molding was performed. For molding, place only the foam metal that is not filled with graphite in the part where the pigtail is joined (the head of the brush), and place the other foam metal filled with treated graphite in the mold by stacking multiple foam metals. Perform compression molding at / cm ² to make a brush shape.

FIG. 2 shows the molding process of the electric brush 1 of this embodiment. As described above, a plurality of foamed metal 3a for the head 3 which are not filled with the pasty graphite are stacked and arranged on the lower punch 7a in the die 8, and the body portion 2 filled with the pasty graphite as described above is placed next to the punched metal 7a. Metal foam 2
A plurality of sheets a were arranged so as to overlap each other (FIG. 2A). Next, temporary molding is performed with a molding pressure of 0.5 Ton / cm ² ((Fig. 2
(B)) The upper punch 7b is removed, and the provisionally formed foam metal 3b for the head 3 is provided with a pigtail mounting hole 5 for providing the pigtail 4, and the pigtail 4 is inserted into the hole 5 (see FIG. 2C). ), The pigtail 4 is installed by pulling out the pigtail 4 from the hole of the upper punch 7c having a hole for taking out the pigtail 4 to the outside, and the main molding is carried out with a molding pressure of 3.5 Ton / cm ² ((Fig. 2 (E)) Then, the assembled semi-finished product with the pigtail 4 having the integrated body portion 2c and head portion 3c was taken out from the die 8. Finally, it was fired at 750 ° C. to obtain the electric brush 1 described above. The copper content of the body 2 was 32% by weight.

With this arrangement, the pigtail 4 made of copper is metal-bonded inside the head 3 made of copper, and good joint strength and low contact resistance can be realized. Further, since the pigtail 4 is not interposed between the body 2 and the head 3 having different compositions, the body 2 and the head 3
It is possible to improve the bonding strength between Further, since the mechanical strength of the head 3 is large, the distance between the pigtail 4 and the base end surface 3d of the head 3 can be shortened, and the brush can be downsized.

Although a foamed porous copper body is used for the head 3 in this embodiment, a solid copper block may be used for the head 3. Other, foam metal 2a, 3a
It is also possible to use a foamed metal having a shape that combines them and also to fill the graphite powder only in the portion to be the body portion.
By doing so, the mechanical joint strength between the body portion 2 and the head portion 3 is improved. Alternatively, the copper fiber aggregate may be filled with graphite powder for molding.

(Embodiment 2) Another embodiment will be described with reference to FIG. In this embodiment, the holes 5 are the same as those in the first embodiment.
And the base end face 3d of the head 3 made of pure copper
The tip portion of the pigtail 4 made of pure copper is placed on the top, and in this state, a carbon dioxide gas laser is irradiated from above the pigtail to join the head portion 3 and the tip portion of the pigtail 4 by laser welding.

In this embodiment, the pigtail 4 made of copper is laser-welded to the base end face 3d of the head 3 by utilizing the fact that the head 3 is made of metal (copper) and has excellent weldability. The body portion 2 and the head portion 3 can be firmly joined together, the head portion 3 can be made thinner than in the first embodiment, and the brush length can be further shortened. In this embodiment, the tip portion of the pigtail 4 is thinner than the other portions, increasing the joining area and increasing the joining force.

Instead of laser welding, the same effect can be obtained by resistance welding between the pigtail 4 and the head 3 by sandwiching the pigtail 4 and the body 2 with an electrode pair and energizing them between the pigtail 4 and the head 3. . Further, according to this embodiment, although the step of retrofitting the pigtail 4 after integrally molding the head part 3 and the body part 2 is adopted, it is possible to obtain the above-described operational effects, and it is different for each model. It becomes easy to attach various pigtails 4 having a cross-sectional area.

(Embodiment 3) Another embodiment will be described with reference to FIG. In this embodiment, the pigtail 4 is fixed to the base end surface of the head 3 by caulking the head 3 and plastically deforming it, and a simple and quick process can be adopted without requiring high temperature heating. The effects of the second embodiment can be achieved.

That is, a tall ridge 35 extending in one direction is formed in the central portion of the base end surface of the head 3, while
At the tip of the pigtail 4, there is formed a groove that fits with the protrusion 35. Then, with the protrusion 35 fitted in the groove (see FIG. 4A), the top of the protrusion 35 protruding from the pigtail 4 is crushed (see FIG. 4B), and the pigtail 4 is moved to the head. Fix to 3.

That is, in this embodiment, a structure for caulking and joining is provided on the base end surface of the head 3 made of copper having excellent conductivity and ductility, and the head 3 is also attached to the tip of the pigtail 4. The structure for fitting with the above-mentioned structure for caulking and joining is provided, whereby the pigtail 4 is retrofitted to the head 3 which is joined to the body 2 in advance by a non-heating method, and the process is extremely simple. Becomes

(Embodiment 4) Another embodiment will be described with reference to FIG. In this embodiment, the pigtail 4 in Embodiment 1 is formed into a rectangular shape whose side in the wear direction is a short side. In this case, the wear of the head 3 is reduced without reducing the sectional area of the pigtail 4. The width in the direction can be compressed.

The technical idea of this embodiment can be applied to a conventional electric brush whose head 3 is also mainly made of graphite. Further, the above-mentioned technical idea and operation and effect of this embodiment can be realized by flattening at least only the tip portion of the pigtail 4. FIG. 7A shows a state before crimping, and FIG. 7B shows a molded electric brush. When the electric brush having an effective wear length of 6 mm is formed by joining by the above-mentioned various methods, the conventional method of inserting the tip of the pigtail 4 into the hole on the side surface and fixing the powder requires a total length of 10.5 mm. The electric brushes of the examples can hold the total length within the range of 8.2 to 8.6 mm,
It was confirmed that the electric brush could be made smaller.

(Embodiment 5) Another embodiment will be described with reference to FIG. In this embodiment, the pigtail 4 in FIG. 3 is composed of a leaf spring made of an elastic conductive metal (for example, beryllium copper), and the tip end of the pigtail 4 is placed on the base end face of the head 3 with a laser as in the second embodiment. Welded.

That is, in this embodiment, attention is paid to the fact that the head 3 has the shape of a copper plate which can be welded to the pigtail 4 and which is well integrally joined to the body 2. By welding, the pigtail 4 also serves as a spring. The contact resistance with the brush can be significantly reduced as compared with the conventional elastic pressing method. Of course, the same effect can be obtained by performing resistance welding instead of the above laser welding.

(Sixth Embodiment) Another embodiment will be described with reference to FIG. In this embodiment, similarly to the third embodiment (see FIG. 6), the tip end of the pigtail 4 is caulked and fixed to the base end surface of the head 3, and the pigtail 4 is made of an elastic conductive metal (for example, beryllium copper). It is a leaf spring. More specifically, the caulking protrusion 36 provided upright at the center of the base end surface of the head 3 is fitted in the hole of the plate-shaped pigtail 4 (see FIG. 9A).
7 is crushed and the pigtail 4 is crimped to the base end surface of the head 3 (see FIG. 9B). The shape of the caulking protrusion 36 and the caulking method can be appropriately selected.

By doing so, Example 3 and Example 5
It is possible to exert the effect of. (Embodiment 7) Another embodiment will be described with reference to FIG. In this embodiment, a press-fitting projection 45 provided on the main surface of the tip end of a pigtail 4 which constitutes a leaf spring is made of an elastic conductive metal (for example, beryllium copper) as a hole 3 provided on the base end surface of the head 3.
The contact resistance can be reduced by the same simple process as in the sixth embodiment.

(Embodiment 8) Another embodiment will be described with reference to FIG. In this embodiment, the tip end portion 48 of the plate-shaped pigtail 4 forming the spring is press-fitted (may be powdered or integrally molded) into a hole formed in the side surface of the head portion 3,
The contact resistance of the spring type pigtail 4 can be reduced as compared with the conventional case. Moreover, since the head 3 is made of copper, the length in the wear direction can be shortened. Further, the pigtail 4 has a leaf spring shape, and the thickness direction thereof coincides with the wear direction, so that the required thickness of the head 3 can be reduced.

If the size of the head 3 between the base end surface of the head 3 and the pigtail 4 is increased, the head 3 may be made of black powder as in the conventional case. Further, in this embodiment, the pigtail 4 is fixed to the head 3 by press fitting, but it may be fixed by powder stopping, and a flat (compressed in the wear direction) corner provided on the side surface of the head 3 may be used. After putting the pigtail 4 in the hole, the head 3 with the pigtail 4 and the body 2 are attached to the first embodiment.
As described above, pressure may be applied to integrally mold.

Hereinafter, the conventional spring-equipped pigtail type electric brush in which the leaf spring type pigtail 4 is pressed against the base end face of the brush head 3 and the above-mentioned welding type (Example 5) and caulking type (Example 6). The contact resistance between the pigtail 4 and the head 3 in the electric brush of each of the press-fitting type (Example 7) and the fitting type (Example 8) is shown below. However, the current is 1A
The measurement was based on the voltage drop ΔV between the pigtail 4 and the brush 1. The internal resistance loss of the pigtail 4 and the head 3 is sufficiently smaller than the contact resistance between the pigtail 4 and the head 3 and can be ignored.

[0041] From the above results, it can be seen that the contact resistance can be significantly reduced. This is because the head 3 is made of copper and can be easily integrated with the pigtail 4 by a method such as welding, caulking, press fitting, or integral molding.

[Brief description of drawings]

FIG. 1 is a side view for explaining an electric brush according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a forming process of the electric brush of FIG.

FIG. 3 is a schematic side view showing an electric brush of Example 2.

FIG. 4 is a schematic perspective view showing an electric brush of Example 3, where (a) shows before caulking and (b) shows after caulking.

FIG. 5A is a perspective view for explaining a molding process of an electric brush according to a fourth embodiment, and FIG. 5B is a perspective view of the molded electric brush.

FIG. 6 is a schematic perspective view showing an electric brush of Example 5.

7A and 7B are schematic side views showing an electric brush of Example 6, where FIG. 7A shows before caulking and FIG. 7B shows after caulking.

FIG. 8 is a schematic side view showing an electric brush of Example 7.

FIG. 9 is a schematic side view showing an electric brush of Example 8.

[Explanation of symbols]

 1 Electric brush 2 Body 3 Head 4 Pigtail

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshio Miyata, 1-1, Showa-cho, Kariya city, Aichi prefecture, Nihon Denso Co., Ltd. (72) Inventor, Nobuyuki Hayashi, 1-1, Showa-cho, Kariya city, Aichi prefecture Within the corporation

Claims (8)

[Claims] 1. A brush in which a head having a good conductivity metal as a main component and forming a base end is integrated with a body having graphite as a main component and forming a tip and a center, and the body has a brush. An electric brush comprising: a pigtail that is joined to the outer end surface or the inside of the head without contact. 2. The electric brush according to claim 1, wherein the pigtail is fixed to an outer end surface of the head portion of the brush. 3. The electric brush according to claim 1, wherein the pigtail is inserted into a hole in the head of the brush. 4. The electric brush according to claim 1, wherein the pigtail also serves as a spring for pressing the brush. 5. A brush is prepared in which a head having a good conductivity metal as a main component and having a base end portion is integrated with a body portion having graphite as a main component and forming a tip end portion and a central portion for power feeding. The method of manufacturing an electric brush, wherein the tip end of the pigtail is fixed to the outer end surface or the inside of the head without contacting the body by welding, caulking, press fitting, powdering, or integral molding. 6. The method of manufacturing an electric brush according to claim 5, wherein the pigtail is formed integrally with the body together with the head. 7. After fitting the tip end of the pigtail into a recess or hole formed in the outer end surface or side surface of the head integrated with the body portion, welding or caulking or powdering both of them together. The method of manufacturing an electric brush according to claim 5, wherein the electric brushes are joined together. 8. An electric brush comprising: a brush whose main component is graphite; and a pigtail which is inserted and fixed inward from a side surface of a head of the brush, wherein a cross section of the pigtail in a direction perpendicular to a longitudinal direction of the pigtail. Is an electric brush having a flat shape in which the width of the brush in the wear direction is compressed.