JPH08126259A - Carbon commutator - Google Patents

Abstract

PURPOSE: To make a commutator excellent in wear resistance and besides, cut down the cost without affecting alcohol, etc., in gasoline. CONSTITUTION: A plurality of commutator pieces 12 arranged through slits 15 are joined with each other by the boss part consisting of synthetic resin having electric insulation property. These commutator pieces 12 consist of sliding layers 13 made of carbon powder and metallic conductive layers 14 made of metallic powder, and for this metallic conductive layer 14, the riser piece 14a projected from the outside periphery and the projection engaging with the boss part 11 are made integrally.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a commutator using carbon for a sliding surface with which a brush comes into contact, and more particularly to a commutator useful for a motor for a fuel supply pump.

[0002]

2. Description of the Related Art In automobiles, a motor for a fuel supply pump is used to supply fuel. Gasoline used as fuel is gasoline with alcohol called gasohol or bad gasoline with unreasonably mixed alcohol. is there. When these gasolines are used, the copper of the commutator used in the motor of the fuel supply pump reacts with the alcohol in the gasoline to reform the fuel itself, or the copper erodes and deteriorates the commutator function. There is a problem causing it.

FIG. 7 shows an example of the commutator as a countermeasure against gaso holes. The flat commutator 1 has a boss portion 2 formed in a disk shape from a resin and a circumferential direction on one end surface of the boss portion 2. It is provided with a plurality of segments 3 arranged at equal intervals, a riser piece 4 integrally formed in each segment 3, and a slit 5 for electrically separating adjacent segments 3 from each other. Further, the segment 3 includes a base material 6 made of copper, and a protection portion piece 7 made of silver-nickel alloy or the like welded to a surface of the base material 6 where a brush (not shown) slides. A not-shown claw for fixing the segment 3 to the boss portion 2 is provided. The surface of the segment 3 is covered with a metal plating film 8 made of tin or the like that does not adversely affect the gasohole, and the outer surface of the protection piece 7 has an exposed surface 9 from which the metal plating film 9 is removed. There is.

In the conventional commutator, the protective material 7 such as silver-nickel alloy is welded to the base material 6 made of copper, or the outer surface of the protective material 7 is coated with the metal plating film 9 once in the next step. A large number of manufacturing steps are required for manufacturing such as removing and forming the exposed surface 10, and since an expensive metal material such as a silver-nickel alloy is used, the cost is inevitably increased. is there. Further, since the protective part 7 on which the brush slides is thin and has poor durability, and the surface is modified with time, there is a problem that the startability deteriorates after a long period of non-operation.

[0005]

Therefore, in view of the above problems, the present invention intends to provide a commutator which is not affected by alcohol and the like in gasoline, is excellent in abrasion resistance, and can be manufactured at low cost. To do.

[0006]

DISCLOSURE OF THE INVENTION In view of the above problems, a plurality of commutator pieces arranged in a flat or cylindrical shape through slits and riser pieces respectively joined to the commutator pieces are provided. And a boss made of a synthetic resin having electrical insulation and having a shaft hole formed in the center of the commutator pieces, wherein the plurality of commutator pieces are made of carbon powder. And a metal conductive layer formed of metal powder. The metal conductive layer has a riser piece integrally formed on the outer periphery and a protrusion that engages with the boss. This is the summary.

[0007]

In the commutator of the present invention, a plurality of commutator pieces are formed into an integral two-layer structure by forming a sliding layer made of carbon powder and a metal conductive layer made of metal powder by powder metallurgy or the like. Since the powder metallurgy method, of which mass production technology has already been established, can be adopted in the manufacturing process, it can be formed with stable quality and at low cost. Further, since the riser piece is integrally formed on the metal conductive layer so as to project, the number of parts is reduced and the cost is further reduced. Further, when the sliding layer is made of a carbon material, it has excellent chemical resistance and chemical stability, so that it is not affected by alcohol in gasoline and reforming of gasoline itself is prevented.

[0008]

1 to 4 show an embodiment of a flat commutator according to the present invention. FIG. 1 is a half sectional view of the commutator.
2 is a plan view thereof, FIG. 3 is a sectional view showing a state of an intermediate step of FIG. 1, and FIG. 4 is a rear view showing a structure of the rear surface of FIG.

1 to 4, a flat commutator 1 is provided.
0 indicates that a plurality of commutator pieces 12 are located at equal intervals in the circumferential direction at positions corresponding to individual metal plates on one end surface of a boss portion 11 formed in a disk shape by a synthetic resin having electric insulation. It is arranged. The commutator piece 12 has a two-layer structure including a sliding layer 13 made of carbon powder and a metal conductive layer 14 made of metal powder. In addition, a slit 15 is provided between adjacent commutators of each commutator piece 12 to electrically isolate each commutator piece 12. The plurality of commutator pieces 12 are individually separated via the slits 15, but these are connected to each other by the boss portion 11. Further, riser pieces 14a are integrally formed on the outer peripheral edge of the metal conductive layer 14 in the radial direction, and a plurality of claws 14b engaging in the boss 11 are integrally formed on the inner side. Has been formed.

At the center of the boss portion 11, there is an axial hole 11 in the axial direction.
a is formed and fitted and fixed to a rotating shaft of a fuel supply pump motor (not shown). Furthermore, each metal conductive layer 1
4 is connected to the winding end of each phase of the motor, and the sliding layer 13 formed of carbon powder of the plurality of commutator pieces 12 is attached to the motor. A pair of brushes made of, for example, carbon are circumferentially contacted, and the motor is driven to rotate by energizing the brushes.

Next, the commutator piece 12 will be described in detail. The sliding layer 13 is made of carbon powder having the same properties as the above-mentioned carbon brush, and a small amount of additive material is mixed in this carbon powder. On the other hand, for the metal conductive layer 14, for example, a conductive metal powder that is chemically stable against alcohol such as nickel or a poor component in gasoline is used. The conductive metal powder may be copper powder whose surface is plated with nickel. Then, a predetermined amount of metal powder is put into a molding die (not shown) and compression-formed by a well-known powder metallurgy method (sintering method), whereby the metal conductive layer 14 is formed.
Are formed into a substantially disc-shaped flat shape. At this time, riser pieces 14a are simultaneously formed in the radial direction on the outer peripheral edge of the metal conductive layer 14, and the claws 14b are integrally formed so as to project inward.

After that, the metal conductive layer 14 is placed in a separate mold, and a predetermined amount of carbon powder is introduced to insert and form both of them by the powder metallurgy method (sintering method). The state shown in FIG. 4 is formed.
The commutator piece 12 thus formed is placed in a molding die (not shown), and the boss portion 11 is insert-molded with a synthetic resin having electrical insulation. At this time,
The claws 14b formed so as to project inward of the metal conductive layer 14 engage with the resin in the boss portion 11 to strengthen the connection between the commutator piece 12 and the boss portion 11.

Thereafter, using a slicer such as a cutting grindstone, the sliding layer 13 of the commutator piece 12 and the metal conductive layer 14 are formed with slits 15 at equal intervals in the circumferential direction up to the boss portion 11. As a result, the commutator pieces 12 are electrically isolated from each other through the slits 15, whereby the flat commutator 10 is completed.

5 and 6 show an embodiment of a cylindrical commutator according to the present invention, FIG. 5 is a sectional view of the commutator, and FIG. 6 is a plan view.

5 and 6, the cylindrical commutator 2 is shown.
In the same manner as in the above-described embodiment, 0 has a plurality of commutator pieces 22 arranged at equal intervals on the outer peripheral surface of the boss portion 21 formed of a synthetic resin in a cylindrical shape. This commutator piece 22
Is the sliding layer 23 formed of carbon powder and the metal conductive layer 2 formed of metal powder, as in the above-described embodiment.
4 has a two-layer structure and is arranged in a cylindrical shape as a whole at equal intervals. Riser pieces 24a are formed to project in the radial direction at one end of the conductive layer 24, and a plurality of claws 24b are integrally formed to project inward.

Further, a slit 25 is provided between adjacent commutator pieces 22 for electrically separating the commutator pieces 22 from each other.
Are provided and are connected to each other by the boss portion 21. A shaft hole 21a is formed in the center of the boss portion 21 in the axial direction, and is fitted and fixed to a rotating shaft of a fuel supply pump motor (not shown).

Next, the manufacturing method will be described. The commutator piece 2
In No. 2, first, the metal conductive layer 24 is compressed into a cylindrical shape by a known powder metallurgy method (sintering method) of a conductive metal powder such as nickel, as in the above-described embodiment. After that, the metal conductive layer 24 is placed in a molding die (not shown), a predetermined amount of carbon powder is charged into the periphery thereof, and compression molding is performed by a powder metallurgy method to form a commutator piece 12 having a two-layer structure. To be done. At this time, a plurality of riser pieces 24a are formed on one end side of the metal conductive layer 24, and a plurality of claws 24b are formed on the inner peripheral surface so as to project.

Then, the boss portion 21 is molded with a synthetic resin so as to expose the plurality of riser pieces 24a. At this time, the claw 24b is embedded in the boss portion 21 to enhance the bonding strength, as in the above-described example.
Then, using a slicer such as a cutting grindstone, the commutator piece 22
By forming the slits 25 at equal intervals in the circumferential direction in the axial direction, the commutator pieces 22 are electrically independent from each other, whereby the cylindrical commutator 20 is completed.

It should be noted that each of the above-mentioned embodiments shows one embodiment of the present invention. In both of the embodiments, not only the two-layer structure of the sliding layer and the metal conductive layer but also the carbon powder between both layers is used. It is also possible to provide a mixing intermediate layer in which the metal powder and the metal powder are mixed at an appropriate ratio, and with this configuration, the difference in physical properties between the two layers can be reduced,
One or more other layers may be formed in the middle, for example, in order to ensure production stability and quality stability. Further, the boundary between the two layers may not necessarily be clear so that the sliding layer on the one surface side is sequentially transferred to the metal conductive layer on the other surface side. Further, the shape and the like are not limited to the embodiments of the present invention, and can be appropriately changed without departing from the present invention.

[0020]

As described above, according to the present invention, since a plurality of commutator pieces are formed by the sliding layer made of carbon powder and the metal conductive layer made of metal powder by the powder metallurgy method or the like, Since the powder metallurgy method of which mass production technology has already been established can be adopted in the manufacturing process, it is possible to provide a commutator with stable quality and at low cost. Further, since the riser piece is integrally formed on the metal conductive layer so as to project, the number of parts is reduced and the cost can be further reduced. Further, when the sliding layer is made of a carbon material, it has excellent chemical resistance and chemical stability, so that it is not affected by alcohol in gasoline and reforming of gasoline itself is prevented.

[Brief description of drawings]

FIG. 1 is a half sectional view showing an embodiment of a flat commutator of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a cross-sectional view showing the state of the intermediate step.

FIG. 4 is a back view showing the configuration of the back surface of FIG.

FIG. 5 is a half sectional view showing an embodiment of a cylindrical commutator of the present invention.

FIG. 6 is a plan view of FIG.

FIG. 7 is a half sectional perspective view showing a conventional commutator.

[Explanation of symbols]

 10 commutator 11 boss portion 12 commutator piece 13 sliding layer 14 metal conductive layer 14a riser piece 15 slit

Claims (3)

[Claims] 1. A plurality of commutator pieces arranged in a flat or cylindrical shape through slits, riser pieces respectively joined to the commutator pieces, and the commutator pieces are connected to each other and are centered on an axis. A commutator comprising a hole-forming electrically insulating boss made of synthetic resin, wherein the plurality of commutator pieces are a sliding layer formed of carbon powder and a metal formed of metal powder. A commutator, comprising: a conductive layer, wherein the metal conductive layer is formed with a riser piece integrally formed to project from the outer periphery and a protrusion that engages with the boss. 2. The commutator according to claim 1, wherein the metal conductive layer of the commutator piece is formed by sintering a conductive metal powder. 3. The commutator according to claim 1, wherein at least the surface of the metal conductive layer of the commutator piece is made of a conductive metal powder made of nickel.