JP2561607B2 - Laminated electric brush and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated electric brush used in a rotary electric machine such as a motor or a generator, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In order to maximize the performance of a motor or generator using an electric brush and to extend the life of the commutator or electric brush, it is important to use an electric brush suitable for the motor or generator. . Then, in order to make an electric brush suitable for various rotating electric machines, various ideas have been made on raw materials used for the electric brush, combinations of the raw materials, a method for manufacturing the electric brush, and the like. In terms of extending the life of commutator and electric brush,
The problem is to suppress the wear of these things.

It is known that a laminated electric brush is effective for preventing abrasion of the electric brush and commutator. For example, when the sliding front portion is the low resistance layer 02 and the sliding rear portion is the high resistance layer 03, as in the laminated electrophotographic brush 01 of FIG. 9,
It is possible to suppress rectifying sparks when the electric brush 01 separates from the commutator segment (commutator bar) and suppress wear. However, it is necessary to further reduce the abrasion of the electric brush and commutator.

On the other hand, the inventors of the present invention have made it possible for the proportion of the low resistance layer and the proportion of the high resistance layer to gradually change with the rotation of the commutator at the contact portion between the electric brush and the commutator. Then, they found that the wear could be further reduced. In addition, it was found that by doing so, the magnetic noise of the rotating electric machine can be reduced and the noise of the motor can be reduced. However, it is difficult to manufacture such a laminated electric brush using a normal press machine.

FIG. 8 shows a general method of forming an electric brush by a compression press. The figure schematically shows the molding of an electric brush by a compression press in a parallel cross section in the pressing direction. In the figure, 1 is a die fixed to the press body, 2 is a lower punch that constitutes the bottom of the die and operates up and down, 3 is an upper punch that constitutes the top of the die and operates up and down, 4 is a die space 5
The upper punch 3 has a lead wire 6 for forming a pigtail of an electric brush, which is a feeder for supplying powder to the upper punch 3. First, the feeder 4 is moved forward, and the mold space 5
After the powder is supplied to and the feeder 4 is retracted, the powder is pressed by the upper punch 3 and the lower punch 2 to fix the lead wire 6 to the main body of the electric brush. Next, the main body of the electric brush is pushed up by the lower punch 2, the lead wire 6 is cut, and the electric brush is taken out from the mold space 5.

However, in order to manufacture a laminated electric brush in this step, two feeders are prepared, the mold space 5 is filled with the powder of the first layer, and then the lower punch 2 is pulled down to newly generate the mold. The space is filled with the powder of the second layer from the second feeder. For this purpose, it is necessary to manufacture a special compression press device. Even if such a compression press machine is manufactured, the boundary surface between the two layers has a lower punch 3
Only parallel to the top surface of. Therefore, in the contact with the commutator, the contact shifts from the low resistance layer to the high resistance layer all at once, and the contact with the low resistance layer cannot be gradually changed to the contact with the high resistance layer.

[0007]

An object of the present invention is to 1) suppress wear of both an electric brush and a sliding partner and reduce magnetic noise.
2) To make it possible to easily manufacture an electric brush satisfying the above-mentioned problems by using a normal compression press machine.

[0008]

Laminated Densuriko of the present invention SUMMARY OF THE INVENTION], in Densuriko laminated to at least two layers of different materials compositions, sliding
Along the sliding direction from the front part to the sliding rear part,
At least one intersecting line between the boundary surface between the two layers and the sliding surface of the electric brush is arranged obliquely to the sliding front end surface of the electric brush so that the composition gradually changes. And
Therefore, as the commutator segment rotates,
The contact between the segment and the electric brush gradually from the first layer to the second layer
Changes to. In this specification, the front end surface of the sliding portion of the electric brush is used as a reference for "oblique", but the end surface of the rear sliding portion is the same.

When the present invention is described assuming that the number of layers is two, the overall shape of the first layer and the second layer is, for example, a rectangular parallelepiped shape, and when one shape is determined, the other shape is a rectangular parallelepiped shape. It is determined as excluding it. Therefore, the shape of either the first layer or the second layer will be described. For example, when viewed in a cross section parallel to the sliding surface of the electric brush, for example, a triangular shape or a trapezoidal shape,
It has an arc shape or a pentagonal shape. However, a triangular shape, a trapezoidal shape, and an arc shape are preferable, and the shape is simpler and the manufacturing is easier than the pentagonal shape, for example. Since the preferable shape of the first layer or the second layer when viewed in cross section is a triangular shape, a trapezoidal shape, or an arc shape, the preferable shape of the first layer or the second layer is a triangular pillar shape, a trapezoidal pillar shape, or an arcuate pillar shape. Also the first
The boundary surface between the layer and the second layer is not limited to one plane. For example, when the cross section has an arc shape, the boundary surface becomes a curved surface, and when the cross section has an equilateral triangle shape, the boundary surface becomes two flat surfaces. Therefore, the line of intersection with the sliding surface includes not only a straight line but also a curved line, two straight lines, etc. “Slant” is any part of it, preferably a part that is at least half the length of the line of intersection. It means that it is diagonal.

As shown in FIGS. 12 to 15, it is also possible to use, for example, an electric brush laminated in three layers. For example, in FIG.
Then, 121 is the first layer, 122 is the second layer, and 123 is the third layer.
In the layers, the same material is used for the first layer 121 and the third layer 123, and there are two boundary surfaces 126 and 127. In this case, the line of intersection of the boundary surface 126 or the boundary surface 127 with the sliding surface may be oblique to the sliding front end surface of the electrophotographic brush.

Such a laminated electric brush has, for example, a preformed body obtained by preforming powder of an electric brush material so as to have a substantially rectangular bottom surface and a second surface oblique to the bottom surface.
After being set in the mold so that the bottom surface of the preform is opposed to the bottom side of the mold and the second surface of the preform appears on the upper part of the mold, it is different from the electric brush material of the preform. The powder of the electric brush material is filled into the mold from the upper part of the preform, and pressed to form a laminated electric brush. Here, it is preferable that the preform has a triangular prism shape or a trapezoidal prism shape, and the preform has a substantially rectangular bottom surface, and the bottom surface is brought into contact with the bottom surface of the mold to form an inclined second surface, for example, a triangular prism slope or Make the slope of the trapezoidal column appear above the mold. As the compression press device, a press generally used for powder molding such as a hydraulic press or a cam type mechanical press is used.

[0012]

In the laminated electric brush of the present invention, the contact between the commutator segment and the electric brush gradually changes from the first layer to the second layer, and as a result, wear of both the electric brush and the commutator is prevented. Furthermore, it is possible to suppress the magnetic noise when the motor and the generator rotate. Magnetic noise is one of the noises of rotating electric machines, and suppression of magnetic noise is important for blower motors for air conditioning, etc., which require noise reduction.

In order to manufacture such a laminated electric brush, powder of the electric brush material is preformed into, for example, a triangular prism shape or a trapezoidal prism shape, and after being set so that the substantially rectangular bottom surface faces the bottom surface of the mold. It suffices to fill the upper part of the preform with a material having a different composition and perform compression molding. By doing so, it is possible to mold the laminated electric brush with a single feeder and with a compression press device that is usually used for manufacturing electric brushes.

[0014]

EXAMPLE FIG. 1 and FIG. 2 show a laminated electrophotographic brush of an example.
In FIG. 1, 10 is a laminated electric brush, particularly a main body of the electric brush, 11 is a first layer made of a low resistance material, 12 is a second layer made of a high resistance material, 13 is a sliding front end face, 14 Is a sliding surface, 15 is a boundary surface between the first layer 11 and the second layer 12, and 16 is a line of intersection between the boundary surface 15 and the sliding surface 14. Further, 17 is a pigtail, and in the embodiment, the sliding front end face 13 is a pigtail 1.
7 is a mounting surface. The first layer 11 and the second layer 12 are right-angled triangular prisms, the boundary surface 15 is orthogonal to the sliding surface 14, and the intersection line 16 is obliquely arranged with respect to the sliding front end surface 13. Of course, only one of the first layer 11 and the second layer 12 may have a triangular prism shape and the other may have, for example, a trapezoidal prism shape, depending on the convenience of molding. 1 to 3, the surfaces are indicated by leader lines with arrows, the boundary surfaces 15 and the like are finely hatched, and the sliding surfaces 14 and the like are coarsely hatched. 2 has a trapezoidal cross section (cross section parallel to the sliding surface 14) of the first layer 21 and the second layer 22, and the boundary surface 25 has a sliding front end surface 13 With respect to the sliding front end face 13, the intersection line 26 appears obliquely with respect to the sliding front end face 13. The first layers 11 and 21 and the second layers 12 and 22 have different compositions, for example, different resistivities.
Either side may be a low resistance layer, but preferably, the side of the first layers 11 and 21 to which the pigtail 17 is fixed has a low resistance to reduce the contact resistance with the pigtail 17. FIG.
The laminated electro-brush 30 of a modification is shown in FIG. In the figure, 31
Is a first layer made of a low-resistance material, 32 is a second layer made of a high-resistance material, and has a columnar shape of an obtuse isosceles triangle.
Reference numerals 5 and 36 denote boundary surfaces between the first layer 31 and the second layer 32,
37 is the line of intersection between the boundary surface 35 and the sliding surface 14, 39 is the boundary surface 3
6 is the line of intersection of the sliding surface 14.

FIG. 4 shows a state in which the rotary electric machine is assembled. Reference numeral 40 in the drawing is a commutator segment, in which the first layer 11 in the front part of sliding of the laminated electrophotographic brush 10 is a low resistance layer and the second layer 12 in the rear part of the sliding is a high resistance layer. The laminated electric brush 10 of the embodiment is the same as a known laminated electric brush in that two layers are laminated, and the second layer 12 at the sliding rear portion is a high resistance layer, and the electric brush 1
Reduces commutation sparks as 0 leaves the commutator segment 40. Further, in the embodiment, the line of intersection 16 between the sliding surface 14 and the boundary surface 15 is arranged obliquely with respect to the sliding front end surface 13, and as a result, the contact area between the commutator segment 40 and the first layer 11 is segmented. The contact with the segment 40 is reduced gradually as the first layer 1 rotates.
Smoothly change from 1 to the second layer 12. It is presumed that this is the cause of suppressing the abrasion of the laminated electric brushes 10, 20 and the commutator segment 40 and reducing the magnetic noise.

The laminated electric brushes 10 and 20 as described above are manufactured by using a preformed body preformed using the molds 50 and 60 shown in FIGS. For compression molding, the normal compression press device shown in FIG. 7 is used. For example, in the case of manufacturing the laminated electric brush 10 of FIG. 1, the mold 50 of FIG. 5 is filled with a high resistance material and preformed. For example, a small amount of a binder resin solution is added to a mixture of graphite and copper powder, kneaded, filled in a mold 40, and dried and solidified. Alternatively, it is heated and solidified in the mold 50. Similarly, in order to manufacture the laminated electric brush 20 of FIG. 2, a high resistance material is preformed with the mold 60 of FIG. The strength of the preformed material may be such that it can be picked up by hand or vacuum sucked by a machine to carry it to the die of the press machine. The softer the preform is, the more easily it is deformed during press forming, the better the first layers 11 and 21 and the second layers 12 and 22 are, and the tighter the interfaces 15 and 25 can bond them together. These molds 50 and 60 are simple molds, and preforming is easy.

The press molding process is shown in FIG. The pressing device itself is the same as that shown in FIG. 8, and for example, a preform 71 formed into a right-angled triangular prism shape with a die 50 is inserted into the die space 5. At this time, the right triangular prism is inserted so that the slope of the right triangular prism appears above the mold space 5. The right-angled triangular prism has three square surfaces, but one of the two surfaces except the inclined surface is brought into contact with the bottom surface of the mold space 5. Next, powder 72 of low resistance material is fed from the feeder 4.
Is supplied and filled, and the upper punch 3 is lowered and the lower punch 2 is raised to perform compression molding. Then the molded body 71
Powder collapsed and compressed, powder 72 supplied from feeder 4
Familiar with and combine. Next, the upper punch 3 is pulled up, the laminated punch 10 is pushed up by the lower punch 2, and the lead wire 6 is cut, so that the laminated brush 10 can be molded. Then, according to a conventional method, for example, sintering or heat curing is performed at about 200 to 800 ° C. to obtain a laminated electric brush.

[0018]

[Test Example] With respect to the laminated electric brush 10 of the example, wear characteristics and magnetic sound characteristics were measured. The laminated electric brush 10 (Example) of FIG. 1, the laminated electric brush 01 of FIG. 9, and FIG.
Using ordinary 1-layer electric brush 04 (comparative example), it was installed in an automobile air-conditioning blower motor (ferrite motor, 12 commutator segments), and a continuous motor for 2000 hours with a load current of 12V and 6.5 Amp. We ran the car and examined the wear condition and the magnitude of the magnetic noise from the motor.
The resistivity of the material of the electric brush is 250 for the low resistance layer 10, 02.
The high resistance layers 12, 03 have a resistance of 250 μΩcm, and the high resistance layer 12, 03 has a resistance of 250 μΩcm. These are all metallic graphite materials, and the resistivity was adjusted by changing the metal content. Table 1 shows the abrasion states of the commutator and the electric brush after 2000 hours and the degree of magnetic noise during operation. As is clear from Table 1, in the embodiment, both the electric brush and the commutator are less worn, and the life of the rotating electric machine such as a motor can be extended. In addition, the magnetic noise is small, and the noise reduction of the motor etc. can be promoted.

[0019]

[Table 1] Table 1 Test Results Resistivity Rotational Speed Electrobrush Wear Amount Commutator Magnetic Noise * (μΩcm) (rpm) (mm) Abrasion Amount (mm) Example 250 2190 2.7 0.05 Ultrafine (Fig. 1) 960 Comparative Example 1 250 2120 3.1 0.08 Slightly (Fig. 9) 960 Comparative Example 2 250 2110 4.2 0.13 Small (Fig. 10) ... * Magnetic sound is evaluated by hearing.

The electric brush of the present invention can be variously modified, and for example, the electric brush of FIGS. 11 to 15 may be used. These drawings are views of the electric brush as seen from the sliding surface 14 side, and it is difficult to form the pigtail 17 side as a preformed body by the manufacturing method of the embodiment. A molded body is used. The boundary surface in FIGS. 11 to 15 is in the direction perpendicular to the paper surface. In the electric brush 110 of FIG. 11, 111 is a low resistance first layer and 112 is a high resistance second layer.
6 has an arc shape. In the electric brush 120 of FIG. 12, 1
21 is a low resistance first layer, 122 is a high resistance second layer, 12
3 is a low resistance third layer, the second layer 122 is manufactured from a triangular preform, and the first layer 121 and the third layer 123 are manufactured from a powder material. 126 and 127 are intersection lines. FIG.
In the electric brush 130 of No. 3, 131 is the first layer of low resistance, 13
2 is a high resistance second layer, and 133 is a high resistance third layer.
The layer 132 and the third layer 133 are manufactured from a triangular shaped preform. 136 and 137 are intersection lines. In the electric brush 140 of FIG. 14, 141 is a low-resistance first layer, 142 is a high-resistance second layer, 143 is a low-resistance third layer, and the second layer 142 is manufactured from a triangular preform. . 146 and 147 are intersection lines. Further, in the electric brush 150 of FIG.
Is a low resistance first layer, 152 is a high resistance second layer, 153 is a low resistance third layer, and 156 and 157 are intersection lines. Also in this electric brush 150, the second layer 152 is manufactured from a preformed body. Each of these electric brushes can be molded by the manufacturing method of FIG. 7 using a preform, and the wear characteristics and magnetic noise of the electric brush and commutator are almost the same as those of the electric brush of FIGS.

[0021]

According to the present invention, it is possible to obtain a laminated electro-brush which has less wear on both the electro-brush and the sliding partner and has a small magnetic noise when the motor or the like rotates. In addition, in the method for manufacturing a laminated electric brush of the present invention, using a normal compression press device,
The laminated electrophotographic brush as described above can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a perspective view of a laminated electric brush according to an embodiment.

FIG. 2 is a perspective view of a laminated electric brush according to an embodiment.

FIG. 3 is a perspective view of a laminated electric brush of a modified example.

FIG. 4 is a perspective view showing a usage state of the laminated electric brush of the embodiment.

FIG. 5 is a perspective view showing a form of the preformed body used in the examples.

FIG. 6 is a perspective view showing a form of the preformed body used in the examples.

FIG. 7 is a process drawing showing a manufacturing process of a laminated electric brush in an example.

FIG. 8 is a process diagram showing a manufacturing process of an electric brush in a conventional example.

FIG. 9 is a perspective view showing a laminated electric brush in a conventional example.

FIG. 10 is a perspective view showing an electric brush in a conventional example.

FIG. 11 is a bottom view of a laminated electric brush of a modified example.

FIG. 12 is a bottom view of a modification of the laminated electric brush.

FIG. 13 is a bottom view of a modification of the laminated electric brush.

FIG. 14 is a bottom view of a modification of the laminated electric brush.

FIG. 15 is a bottom view of a modified electro-deposited brush.

[Explanation of symbols]

 1 Mold 2 Lower Punch 3 Upper Punch 4 Feeder 5 Mold Space 6 Lead Wires 10, 20, 30 Multilayer Electrobrush 11, 21, 31 Low Resistance Layer 12, 22, 32 High Resistance Layer 13 Sliding Front End Face 14 Sliding Surface 15, 25, 35, 36 Boundary surface 16, 26, 37, 38 Intersection line 17 Pigtail 40 Commutator segment 50, 60 Form 71 Preform 72 Powder

Claims (5)

(57) [Claims] 1. An electrobrush in which materials having different compositions are laminated in at least two layers, and sliding from a sliding front portion to a sliding rear portion.
As the composition of the electrobrush material changes gradually along the direction
At least one of the lines of intersection between the boundary surface between the two layers and the sliding surface of the electric brush is arranged obliquely with respect to the sliding front end surface of the electric brush. 2. The laminated electrographic brush according to claim 1, wherein a cross-sectional shape of a cross section of at least one of the two layers, which is parallel to the sliding surface of the electrographic brush, is substantially triangular. 3. The laminated electrographic brush according to claim 1, wherein at least one of the two layers has a substantially trapezoidal cross-sectional shape in a cross section parallel to the sliding surface of the electrographic brush. 4. A method for manufacturing a laminated electrographic brush, wherein a powder material is compression-molded in a die of a compression press, having a substantially rectangular bottom surface and a second surface oblique to the bottom surface. In addition, the preform formed by preforming powder of the electrobrush material is arranged so that the bottom surface of the preform is opposed to the bottom side of the mold and the second surface of the preform appears on the upper part of the mold. Then, after setting in the mold, the powder of the electric brush material different from the electric brush material of the preform is filled into the mold from the upper part of the preform and pressed to form the laminated electric brush. A method for manufacturing a laminated electric brush, comprising: 5. The method for manufacturing a laminated electrographic brush according to claim 4, wherein the preform has a substantially triangular column shape or a trapezoidal column shape.