JPH0888066A - Commutator and its manufacture - Google Patents

Abstract

PURPOSE: To obtain a commutator with a high anticorrosion property for fuel containing alcohol at a low cost. CONSTITUTION: A commutator 1 has plural segments 21 made by sintering a carbon powder, and riser pieces 4 whose insert members 6 are inserted to the segments 21, so as to fix them integrally. The segments 21 are arranged circularly in the condition insulating each other, and unified by a boss 16 formed of a resin, and the riser pieces 4 of the segments 21 are projected from the outer peripheral surface of the boss 16. Since the riser pieces 4 are insert-formed to the carbon segments 21, they are connected mechanically and electrically without connecting process using a soldering process or a conductive adhesive. As a result, the manufacturing process is simplified. And since no adhesive is used, the antialcohol property is excellent. The segments made of a carbon are never corroded by the fuel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a commutator and a method for manufacturing the same, and more particularly to a commutator whose segments are made of carbon. For example, a motor is integrated with a pump, and fuel passes inside the motor. The present invention relates to an effective fuel supply pump of the type

[0002]

2. Description of the Related Art Generally, as a fuel supply pump for supplying fuel to a vehicle such as an automobile, there is an in-tank type fuel supply pump in which a motor is assembled integrally with the pump and installed inside a fuel tank. In this in-tank type fuel supply pump, it is usual that fuel is sent from the pump to the outside through the inside of the motor housing. In this case, fuel comes into contact with the commutator of the motor. However, when gasoline containing alcohol is used as fuel, when the copper in the commutator used in the motor of the fuel supply pump comes into contact with the alcohol in the fuel, the copper in the commutator that slides on the brush is Known to be eroded.

Therefore, as a commutator for preventing fuel containing alcohol, for example, as described in US Pat. No. 5,175,463, graphite (graphite) is formed on at least a surface of a copper base material of a segment (commutator element) which is in contact with a brush. It has been proposed that a protective piece consisting of) is applied by soldering.

However, since graphite has almost no solder wettability, a technique of soldering after nickel plating and copper plating are applied to at least the soldering surface of the protective part made of graphite, or an alternative to soldering is conductivity. A technique has been proposed in which a graphite protection piece is bonded to a copper base material using an adhesive.

[0005]

However, the technique of plating the protective piece made of graphite requires a plating step, which increases the manufacturing process and the manufacturing cost. On the other hand, in the technique of bonding with a conductive adhesive, the conductive adhesive is inferior in alcohol resistance, so that measures against alcohol-containing fuel become insufficient.
Further, in both the plating technique and the bonding technique using a conductive adhesive, the work of joining the protective part and the copper base material is complicated and difficult, so the stability of the commutator quality and its production efficiency are improved. Will fall.

In addition, in the conventional commutator for preventing fuel containing alcohol, which uses graphite, it is difficult to select the optimum material because it is necessary to cut the solid matter of graphite into a desired plate shape. Not only that, it becomes extremely expensive.

An object of the present invention is to provide at low cost a commutator having high corrosion resistance against alcohol-containing fuel.

[0008]

A commutator according to the present invention comprises a plurality of segments in which carbon powder is sintered and a conductive terminal member partially inserted into each segment and integrally fixed thereto. Each of these segments is annularly arranged in a state of being insulated from each other, and is integrally fixed by a boss portion integrally molded using resin. Each of the members is characterized in that the members are arranged in an annular shape and protrude from the boss portion.

Also, in the method for manufacturing a commutator according to the present invention, a part of the conductive terminal member is inserted into a mold for molding the segment, and the mold is filled with carbon powder,
The method is characterized by including a step of compacting carbon powder to the conductive terminal member to form a solid carbon material, and a step of baking the solid material to burn the segment.

[0010]

When the segment is fired with carbon powder, the conductive terminal member is implanted and the sintered and fixed carbon segment is formed. That is,
The conductive terminal member is integrated with the carbon segment without a soldering process or a bonding process using a conductive adhesive. As a result, the production efficiency is improved, and the bonding strength between the conductive terminal member and the carbon segment is also improved. Moreover, since the segment is formed by the carbon powder, the manufacturing cost is reduced as compared with the case where the solid graphite material is cut out and formed.

Further, since the segments are made of carbon powder, even when the commutator is used in fuel containing alcohol, it is possible to prevent the surface in sliding contact with the brush from being corroded. . Also,
Since the conductive adhesive is not used, sufficient durability can be maintained even when the commutator is used in alcohol.

[0012]

FIG. 1 shows a commutator which is an embodiment of the present invention. (A) is a plan view, (b) is bb of (a).
It is a front sectional view which follows a line. FIG. 2 and subsequent figures are explanatory views showing a method of manufacturing the commutator.

In the present embodiment, the commutator according to the present invention is configured to be used as a rotor of a motor in a fuel supply pump of a type in which fuel passes through the inside of the motor, and also has a flat structure. ing.

The flat commutator 1 according to the present embodiment has a boss portion 16 which is made of an insulating resin and is formed in a thick disk shape, and a boss portion 16 which is formed in a substantially fan shape. A plurality of segments 21 radially arranged at substantially equal intervals on the surface of the, a riser piece 4 as a conductive terminal member electrically connected to each of the segments 21, and adjacent segments 21 to each other. And a slit 20 for providing an electrically insulated state. A shaft hole 1 for inserting and fixing a shaft in the boss portion 16
7 are opened concentrically.

Each segment 21 is formed by sintering carbon powder mixed with an appropriate binder. Each riser piece 4 is made of copper or a copper alloy, and a wide portion 5 and an insert portion 6 are integrally connected to the riser piece 4. Then, each riser piece 4 is attached to each segment 21.
It is arranged on the outer circumference of the
By being implanted in the, each segment 21 is mechanically and electrically connected.

The respective segments 21 are arranged in a circular ring shape and are planted in the boss portion 16 so that their positions are fixed and integrated with the boss portion 16. The riser piece 4 and the wide portion 5 protruding from the outer periphery of each segment 21 are also in a state of protruding from the outer peripheral surface of the boss portion 16. The riser piece 4 and the wide portion 5 protruding from the boss portion 16 are at the base of the wide portion 5 with the boss portion 16, that is, at the end of the wide portion of the insert portion 6 on the side opposite to the exposed surface of the segment 21 (side surface contacting with brush). Is bent at a right angle to the axial direction, and the riser piece 4 is folded back in a V shape at the end of the wide portion.

Next, a method of manufacturing the commutator according to the embodiment of the present invention will be described with reference to the method of manufacturing the commutator 1 having the above-described structure. This description clarifies details of the configuration of the commutator 1 according to the above configuration.

FIG. 2 shows a base plate of a riser piece used for manufacturing the commutator having the above-mentioned structure. (A) is a front sectional view taken along line aa of (b), and (b) is a bottom view. It is a figure.

In FIG. 2, the base plate 2 of the riser piece is made of a copper-based material (copper or copper alloy) and is integrally formed by press working. This riser piece element plate 2 is provided with a ring-shaped portion 3 as a connecting member for connecting the riser pieces in the course of manufacturing. The ring-shaped portion 3 is formed into a circular ring shape with a constant width, and its inner diameter is It is formed to be sufficiently larger than the outer diameter of the flat commutator 1.

A plurality of riser pieces 4 (eight in the illustrated example) are arranged on the inner circumference of the ring-shaped portion 3 at equal intervals in the circumferential direction, and radially project radially inward. A wide portion 5 is integrally formed at the tip portion of the riser piece 4, and each wide portion 5 is set to a size such that adjacent portions do not contact each other. The wide portion 5 is formed in a substantially rectangular plate shape in which one of the outer corner portions is cut out in a triangular shape, and is connected to the riser piece 4 at the outer corner portion opposite to the triangular corner portion. An insert portion 6 formed in a rectangular shape is arranged on the inner end side of the wide portion 5 at a substantially central portion in the width direction, and is radially provided along a normal line. The radial length of the insert portion 6 is set to about ½ of the radial length of the carbon segment, and the circumferential width is set smaller than the segment width.

Further, a locking claw 7 for hooking the insert portion 6 on the boss portion is bent at the inner tip of each insert portion 6 so as to project to the end surface on the side opposite to the exposed surface of the carbon segment. By the way, this locking claw 7 is attached to the ring-shaped portion 3 side so that it can be tilted to the extent that an anchor effect can be exerted before the boss portion is formed after the insert portion 6 is planted in the carbon plate described later. Be bent.

FIG. 3 shows a structure of a carbon plate in which the insert portion of the riser piece plate shown in FIG. 2 is inserted and fired, and (a) is a-a of (b).
Front sectional drawing which follows the line, (b) is a top view. FIG.
(A), (b), (c) is each front sectional drawing which shows the manufacturing process.

The carbon plate structure 11 shown in FIG. 3 is a structure in which the riser element plate 2 is insert-molded on the carbon plate 8 for forming carbon segments. The carbon plate 8 is integrally molded into a circular ring shape by using carbon powder mixed with an appropriate binder and by using the molding die 30 shown in FIG. The carbon plate 8 is formed in a substantially circular ring shape having a width equal to the radial dimension of the segment to be manufactured.
That is, the substantially ring-shaped carbon plate 8 is formed so that its outer diameter is substantially equal to the outer diameter of the segment group and its inner diameter is substantially equal to the inner diameter of the segment group. There is.

On the inner peripheral surface and the outer peripheral surface of the carbon plate 8, the radial width of the carbon plate 8 becomes smaller as the inner tapered portion 9 and the outer tapered portion 10 go in the direction opposite to the locking claw 7. Each is formed. In addition, the inclination angles of both the tapered portions 9 and 10 serve to facilitate the release of the carbon plate 8 from the mold, and also, the boss portion is partly formed in the boss portion after resin molding. The optimum value is set so that the boss portion and each carbon segment can be integrally joined by the shape coupling effect in the engaged state.

The molding die 30 shown in FIG. 4 is an upper die 3.
1, a lower mold 32 and a tamping mold 33 are provided, and a cavity 34 is formed by the upper mold 31 and the lower mold 32. The cavity 34 is formed in a circular ring hole shape similar to the carbon plate 8 in consideration of the shrinkage amount during firing, and a taper portion corresponding to the outer taper portion 10 of the carbon plate 8 is formed. Lower mold 3
On the center line of the second cavity 34, a core 35 corresponding to the shaft hole 17 is projectingly provided in a cylindrical trapezoidal shape.
The outer peripheral taper portion of 5 corresponds to the inner taper portion 9 of the carbon plate 8. On the mating surface of the lower die 32, a recess 36 for accommodating the riser monolithic plate 2 is recessed in a shallow hole shape which is the same as the outer shape of the riser monolithic plate 2.
The depth of 6 is set to be equal to the thickness of the riser monolithic plate 2. The depth of the cavity of the upper die 31 is set so that the depth of the cavity 34 is larger than the thickness of the carbon plate 8 in consideration of the compression allowance of carbon powder.

In using the molding die 30 constructed as described above, first, the riser piece plate accommodating recess 36 of the lower die 32 is formed.
The riser piece plate 2 is housed with the locking claw 7 facing upward. Subsequently, the upper mold 31 is the lower mold 32 and the riser piece plate 2
And a cavity 34 is formed by the upper mold 31 and the lower mold 32. Then, the carbon powder 37 mixed with the binder is filled in the cavity 34 by a preset amount. Then, the tamping mold 33 is fitted into the cavity 34. When the tampering die 33 is inserted by a preset stroke, the carbon powder 37 filled in the cavity 34 is compacted by the molding die 30 with a preset degree of compression.

The solid material of the carbon powder 37 compacted as described above is composed of the tamping mold 33 and the upper mold 31 of the lower mold 3.
After being removed from the mold 2, it is taken out from the cavity 34 of the lower mold 31 and baked in a baking furnace (not shown). In this way, the carbon plate structure 11 shown in FIG. 3 is fired. The binder mixed with the carbon powder is carbonized by this firing.

The carbon plate structure 11 shown in FIG. 3 has a carbon plate 8 on which a riser piece plate 2 is arranged, and each insert portion 6 is radially arranged on the outer peripheral surface of the carbon plate 8 at equal intervals in the circumferential direction. It is constructed by being integrally implanted in a state of being inserted into. That is,
The carbon plate 8 fired in a circular ring shape and the riser piece element plate 2 in which a plurality of riser pieces 4 are radially arranged and connected by a circular ring-shaped portion 3 are concentrically arranged and integrated with each other. The insert portion 6 integrally formed on the tip of each riser piece 4 is radially inserted into the carbon plate 8 from its outer peripheral surface and is integrally implanted. The riser pieces 4 are in a state of being mechanically connected to the carbon plate 8 due to the anchoring effect of the state in which the respective insert portions 6 are embedded in the carbon plate 8. At the same time, the riser piece 4 as the conductive terminal member is in a state of being electrically connected to the carbon plate 8 as the conductive substrate via the insert portion 6.

FIG. 5 shows a resin-integrally molded product after the boss portion is resin-molded, (a) is a front sectional view taken along the line aa in (b), and (b) is a bottom view. .

In the resin-integrally molded product 15 shown in FIG. 5, a boss portion 16 is formed on the end surface of the carbon plate 8 on the side where the locking claw 7 is projected, and an insulating resin is used. It is integrally molded by a pressure molding method (molding method). Here, each locking claw 7 is bent before the boss portion 16 is molded, and is implanted in the boss portion 16 so that it serves as an anchor. On the center line of the boss portion 16, a shaft hole 17 is formed in a cylindrical hole shape by simultaneous molding. An inner taper portion 18 and an outer taper portion 19 are formed inside and outside the carbon plate 8 in the boss portion 16, respectively.
The inner taper portion 9 and the outer taper portion 10 formed on the carbon plate 8 are in a shape-bonded state with each other. Due to the mutual shape-coupling portion, the carbon plate 8 is held by the boss portion 16 so as not to come off in the axial direction.

On the other hand, the riser piece 4 and the wide portion 5 protruding from the outer peripheral surface of the carbon plate 8 are also exposed from the outer peripheral surface of the boss portion 16. Then, after the ring-shaped portion 3 is cut, each riser piece 4
And the wide portion 5 is bent at a root of the boss portion 16 of the wide portion 5, that is, at the end of the insert portion 6 on the wide portion side, at a right angle to the axial direction on the side opposite to the exposed surface of the carbon plate 8 and the riser piece. 4 is folded back into a V shape. Since the carbon plate 8 is securely held by the boss portion 16 and is in an integrated state, each riser piece 4
The wide portion 5 is securely fixed to the boss portion 16.

After that, slits are cut in a part of the carbon plate 8 and the boss portion 16 to manufacture the flat commutator 1 having the above-described structure shown in FIG. That is, a plurality of slits 20 are arranged in the carbon plate 8 and the boss portion 16 of the resin-integrally molded product 15 at intermediate positions between the adjacent riser pieces 4 and 4, respectively, and the cutting tool is aligned with the normal line. It is cut by a suitable means such as cutting (not shown). The slits 20 are cut by cutting the carbon plate 8 to a depth reaching the boss portion 16, and the adjacent ones are electrically independent from each other.
1 is configured substantially. That is, the segment 21 is composed of carbon plate pieces that are separated from each other by the slit 20, and the riser piece 4 as a conductive terminal member is electrically and mechanically connected via the insert portion 6. . And segment 21
Since the locking claw 7 protruding from the end and the wide portion side end of the insert portion 6 are embedded in the boss portion 16, the segment 21 and the boss portion 16 are prevented from rotating in the circumferential direction.

FIG. 6 is manufactured as described above, and
It is each front view and each partial cut side sectional view showing an example of use of constituted flat type commutator 1.

In FIG. 6, the flat commutator 1 is used for a rotor 22 of a DC motor. That is, the flat commutator 1 has the rotor shaft 23 of the rotor 22 and the shaft hole 17
Are fitted and fixed, and the coil 25 of the armature 24 is entwined with each riser piece 4 and electrically connected by a fusing process.

During this fusing process, the riser piece 4 is heated, but the riser piece 4 is integrally planted in the carbon segment 21 through the insert portion 6 so as to be electrically and mechanically connected. Therefore, the adverse effect of heating does not occur. That is, since there is no soldering portion in the above-mentioned conventional technique, it is possible to prevent the occurrence of a trouble that the connection between the riser piece 4 and the segment 21 is damaged due to melting of the soldering portion. It will be.

In the rotor shown in FIGS. 6 (c) and 6 (d), in order to enhance the corrosion resistance of the rotor as a whole and reduce the friction resistance, the entire rotor is sealed with resin. It is resin-sealed by the body 26.

It is needless to say that the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the scope of the invention.

For example, not only the slits are cut into the carbon plate in which the riser piece plate is insert-molded to produce each segment, but also the carbon segments in which the riser pieces are insert-molded are individually fired, and then a plurality of segments are formed. Arranged in a circular ring shape with being separated from each other,
The commutator may be manufactured by forming the boss portion by a pressure molding method using an insulating resin and integrating the boss portion.

Further, although the engaging claws are connected to the insert portion, axial grooves are formed on the inner and outer peripheral surfaces of the segment,
By chamfering the inner and outer corners of the exposed surface of the segment,
The locking claw can be omitted if a recess for locking the boss is formed and resin in the boss is embedded in the recess so as to provide a coupling strength between the segment and the boss.

Although copper or brass is used as the conductive terminal member, iron may be used.

Although the flat type commutator has been described in the above embodiment, the present invention can also be applied to a normal columnar type commutator.

[0042]

As described above, according to the present invention,
Since a commutator is manufactured by integrally implanting a part of the conductive terminal member in the segment fired by the carbon powder, it is possible to reliably connect the segment and the conductive terminal member mechanically and electrically. In addition, the manufacturing process can be simplified. Further, since the segment is formed by sintering carbon powder, the manufacturing cost can be reduced as compared with the case where the solid graphite material is cut out and formed. Further, according to the present invention, since a commutator having a high alcohol resistance can be provided at a low cost, it is possible to provide a fuel supply pump corresponding to various fuels having an alcohol content of 0 to 100%.

[Brief description of drawings]

1A and 1B show a commutator according to an embodiment of the present invention, FIG. 1A is a plan view, and FIG. 1B is a front sectional view taken along line bb of FIG.

2 shows a riser piece plate used for manufacturing the commutator of FIG. 1, (a) is a front sectional view taken along the line aa of (b), and (b) is a bottom view.

FIG. 3 shows a structure of a carbon plate which is a raw plate of a carbon segment used for manufacturing the commutator of FIG. 1, and (a) is a front sectional view taken along the line aa of (b), (B) is a plan view.

4A, 4B, and 4C are front cross-sectional views showing the manufacturing process thereof.

5A and 5B show a resin-integrally molded product after the boss portion has been resin-molded, wherein FIG. 5A is a front sectional view taken along the line aa in FIG. 5B, and FIG. 5B is a bottom view.

6 (a), (b), (c) and (d) are front views and partially cut side sectional views showing examples of use of the flat type commutator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Flat type commutator, 2 ... Riser piece element plate, 3 ... Ring-shaped part, 4 ... Riser piece (conductive terminal member), 5 ... Wide part, 6 ... Insert part, 7 ... Locking claw, 8 ... Carbon plate , 9 ... inner taper part, 10 ... outer taper part, 11 ...
Carbon plate structure, 15 ... Resin integrally molded product, 16
... Boss part, 17 ... Shaft hole, 18 ... Inner taper part, 19 ... Outer taper part, 20 ... Slit, 21 ... Segment, 22
... rotor, 23 ... rotor shaft, 24 ... armature, 25
... coil, 26 ... resin sealing body, 30 ... molding die, 31 ... upper die, 32 ... lower die, 33 ... tamping die, 34 ... cavity, 35 ... core, 36 ... riser piece plate accommodating recess, 37 ...
Carbon powder.

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[Procedure amendment]

[Submission date] December 2, 1994

[Procedure Amendment 1]

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[Name of item to be corrected] Claim 1

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[0008]

SUMMARY OF THE INVENTION A commutator according to the present invention is a conductive terminal member in which a plurality of segments of carbon powder are sintered and a part of each segment is planted and integrally fixed. Each of these segments is arranged in an annular shape in a state of being insulated from each other, and is integrally fixed by a boss portion integrally molded using resin, and the conductivity of these segments is Each of the terminal members is characterized in that the terminal members are arranged in an annular shape and protrude from the boss portion.

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[0009] A method of manufacturing a commutator according to the present invention, a portion of the conductive terminal member into a mold for molding the segments are inserted, the carbon powder is filled in the mold, the conductive terminal members together with The method is characterized by including a step of compacting carbon powder to form a solid carbon material, and a step of baking the solid material to fire the segment.

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During this fusing process, the riser piece 4 is heated, but the riser piece 4 is integrally planted in the carbon segment 21 through the insert portion 6 so that the riser piece 4 is electrically and mechanically connected. Therefore, the adverse effect of heating does not occur. In other words, since there is no soldered part definitive in aforementioned prior art, by which the soldered portion is melted, it is avoided in advance a failure of connection to the riser 4 and segments 21 being damaged occurs Will be.

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[Figure 4]

Claims (2)

[Claims] 1. A plurality of segments in which carbon powder is sintered, and a conductive terminal member partially inserted into each segment and integrally fixed thereto, each of these segments being mutually They are arranged in a ring shape in an insulated state, and are integrally fixed by a boss part that is integrally molded using a resin, and each of the conductive terminal members of these segments is arranged in a ring shape. A commutator characterized by being projected from the boss. 2. The method of manufacturing a commutator according to claim 1, wherein a part of the conductive terminal member is inserted into a molding die for molding the segment, and the molding die is filled with carbon powder to obtain a conductive material. A method of manufacturing a commutator, comprising: a step of compacting carbon powder on a terminal member to form a solid carbon material; and a step of solidifying the solid material and firing a segment.