JP4600744B2 - Manufacturing method of carbon commutator - Google Patents

Description

The present invention relates to a method of manufacturing a carbon commutator used in a motor for a fuel pump of an automobile, and in particular, practically eliminates restrictions on a carbon-based material design with respect to the motor efficiency of the fuel pump and wear during long use. In addition, the present invention relates to a method for manufacturing a carbon commutator that can provide a carbon base and a terminal metal fitting easily and with high reliability.
The carbon base mentioned above is used to slide with the mating brush as the sliding surface of the carbon commutator, and to supply the current from the brush to the coil via the terminal fitting joined to the carbon base. It is what is done.

  Regardless of whether the vehicle is a four-wheeled vehicle or a two-wheeled vehicle, fuel pumps that supply fuel such as gasoline and light oil from a tank to an injector are widely used in automobiles. Conventionally, copper commutators that use copper on the sliding surface have been used for fuel pumps, but the fuel pump efficiency has been improved, the life has been increased, or alcohol-added fuel and sulfur concentration used mainly overseas are high. Recently, for the purpose of improving the corrosion resistance and oxidation resistance of the commutator with respect to fuel and the like, the adoption of a carbon commutator using carbon on the sliding surface has been studied.

  The carbon commutator is a carbon base that is made entirely of carbon, including the sliding surface. After the electrical and mechanical connection of the terminal fittings that anchor the rotor windings to the carbon base, the carbon that excludes the sliding surface and the shaft insertion hole is used. A plurality of segments obtained by molding the periphery and lower part of the base with a thermosetting resin, for example, an insulating heat-resistant resin such as phenol resin, and further dividing the mold part up to the carbon base, the terminal fitting and the lower part of the terminal fitting into a plurality of parts It is manufactured by a process of electrically insulating each other.

  Regarding the joining of the carbon base, which is a component of the carbon commutator, and the terminal fitting, the mechanical strength and firing temperature of the carbon used for the sliding surface, the voltage drop between the carbon base and the terminal fitting due to the joining, the commutator based on the joining strength Various methods have been tried in consideration of the reliability with respect to the destruction of the metal or the manufacturing cost required for joining.

Regarding the joining of the carbon base and the terminal metal fitting, a method of joining a carbon base made of only a carbon material using a brazing material as shown in Patent Document 1, and a surface on the side of the non-rectifying surface as shown in Patent Document 2 A method of shaving and fastening a hole provided in a metal piece to a protruding protrusion, and joining a metal layer by sintering a material that can be alloyed with a conductive terminal member as disclosed in Patent Document 3. There are methods such as joining.
JP-A-11-810968 JP 2002-64958 A Special table WO99 / 08367

  However, the method of joining a carbon base made of only a carbon material using a brazing material, that is, the method shown in Patent Document 1, is to ensure good joint strength between the carbon base and the terminal fitting, A special brazing material containing a certain ratio or more of a specific material that reacts with iron and carbon to form a carbide is required. Since the brazing temperature of such a brazing material is generally 700 ° C. to 1,300 ° C., the cost becomes high. In addition, the carbon materials used were fired at a temperature higher than the brazing temperature in the manufacturing process in order to prevent reduction in bonding strength due to degassing from the carbon material and peeling of the brazing material due to the difference in thermal expansion between the carbon material and the terminal fitting. It is limited to those having high strength and high hardness.

Further, the voltage drop between the carbon base and the terminal fitting is large, and in particular, depending on the type of the carbon material, a crack may occur near the joining boundary. The cause is while the typical copper and the coefficient of linear expansion of the brass used as the terminal fitting is 16.7 × ^{10 -6} /K,17.0×10 -6 / K, respectively, the carbon material Material although there are variations by a 3.0 × ^{10 -6} /K~5.0×10 -6 / degree K, the difference between the material of the carbon-based and the terminal fitting is large, caused by overheating during joining It is thought that cracks occur due to the expansion difference.

  Furthermore, cracks near the joint boundary have a correlation with the bending strength and hardness of the carbon material used for the carbon base when the shape and dimensions of the terminal fitting are the same as the carbon base, and the bending strength and shore hardness of the carbon material are correlated. The higher the height, the less cracking occurs. For example, when using silver brazing (JIS Z-3261BAg-1) and joining the carbon base and terminal fitting with an outer diameter of 20 mm (φ) and a brazing width of 1 mm, the carbon base When a carbon material having a bending strength of 40 MPa or more and a Shore hardness of 45 or more is used, no crack near the joining boundary occurs.

  In order to prevent an increase in voltage drop at the time of joining due to brazing or cracking in the vicinity of the joining boundary, it is solved by using a carbon material having high strength and hardness. However, the brush, which is the counterpart material when used as a fuel pump, has a bending strength that takes into account carbon stagger properties, basic characteristics such as voltage drop, productivity, etc. that affect the performance of the fuel pump. In general, a material having a hardness of about 5 to 30 MPa and a Shore hardness of about 7 to 30 is used. It is known that if the hardness difference between the carbon commutator and the brush as the counterpart material is large, the wear of the lower hardness tends to increase, and a sudden increase in wear called abnormal wear occurs.

  When abnormal wear occurs in either the carbon commutator or the mating brush, the usable time of the fuel pump becomes extremely short, which is not preferable. In addition, carbon commutator wear powder or brush wear powder generated suddenly and in large quantities due to abnormal wear may not be discharged quickly from the fuel pump, and may accumulate in grooves between segments formed in the carbon commutator. There is. If conductive carbon powder accumulates in the groove between the segments, the insulation between the segments is lost, and the fuel pump may stop instantaneously.

  In order to eliminate the above-described problems, it is preferable to reduce the bending strength difference and hardness difference between the carbon base and the counterpart brush, and considering the performance of the fuel pump and the productivity of the brush, It is preferable to use a material whose bending strength and hardness are matched to the brush. However, as described above, in order to obtain sufficient strength in the joining of the carbon base made of only the carbon material and the terminal metal fitting, it is necessary to heat to a certain temperature or higher using a special brazing material. In order to prevent a crack near the boundary with the metal fitting, the carbon material is limited to a high strength and high hardness carbon material having a bending strength and a shore hardness enough to withstand a strain due to a difference in linear expansion coefficient.

  In addition, the method of shaving and fastening the hole provided in the metal piece to the protrusion protruding from the surface on the side opposite to the rectifying surface (method according to Patent Document 2) has a complicated and highly accurate shape of the carbon base. Therefore, the cost is high and the carbon material is limited to one having good workability.

  Furthermore, the metal element used for a conductive terminal member or a metal layer is limited in the method (method by patent document 3) which sinters the substance which can be alloyed with a conductive terminal member, and provides a metal layer. In addition, carbon materials are limited to those fired above the sintering temperature of alloying, while the metal of the metal layer needs to have a lower melting point than the terminal fitting, so the carbon base firing temperature is limited to a narrow range. The

  In addition, the bonding methods according to Patent Document 2 and Patent Document 3 have lower bonding strength than bonding with a brazing material, and cracks and separation are likely to occur near the bonding boundary due to the pressure applied in the subsequent resin molding process. It is not satisfactory in terms of productivity and productivity.

The invention according to claim 1 is simple and highly reliable in joining the carbon base and the terminal fitting while eliminating the carbon base material and the design restrictions as much as possible against the motor efficiency of the fuel pump and wear during long use. The present invention provides a method for producing a carbon commutator that is capable of reducing distortion caused by a difference in linear expansion coefficient and eliminating defects such as cracks.
In addition to the invention described in claim 1, the invention described in claim 2 solves problems such as peeling of different layers and provides a more reliable method for producing a carbon commutator.
In addition to the inventions of claims 1 and 2, the invention described in claim 3 prevents the melting of the brazing material when the carbon commutator is incorporated in the rotor, thereby producing a more reliable carbon commutator. It provides the law.

In the method of manufacturing a carbon commutator having a carbon base and a terminal fitting connected to the carbon base, the present invention forms the side that slides with the brush of the mating member from a carbon material, while the side connected to the terminal fitting is It comprises a metal powder and carbon powder, and to produce a carbon-based form the two-layer structure in admixture with a linear expansion coefficient of ^{6.0 × 10 -6 /K~18.0×10 -6 / K} , then The carbon base and the terminal fitting are joined with a brazing material , and then the carbon base is fixed by molding the resin base around the carbon base sliding surface and the periphery of the carbon base excluding the shaft insertion hole, and then fixing the carbon base. A car comprising: a terminal metal part and a mold part up to a lower part of the terminal metal part, and a plurality of segments in which adjacent parts are electrically insulated from each other. It relates to a process for the preparation of emissions commutator.

Further, the present invention provides the method for producing a carbon commutator, wherein the mixed material containing metal powder and carbon powder contains metal powder in a range of 15 wt% to 85 wt% with respect to the mixed material. About.
Furthermore, the present invention relates to a method for producing the carbon commutator, wherein the carbon base and the terminal fitting are joined electrically and mechanically using a brazing material having a melting point of 500 ° C. or higher. .

The carbon commutator obtained by the method according to claim 1 is a joint between the carbon base and the terminal metal fitting while eliminating the carbon base material and design restrictions as much as possible with respect to the motor efficiency of the fuel pump and wear during long use. Is simple and highly reliable, reduces distortion caused by the difference in linear expansion coefficient, and eliminates defects such as cracks.
In addition to the carbon commutator according to claim 1, the carbon commutator obtained by the method according to claim 2 eliminates problems such as separation of different layers and is more reliable.
In addition to the carbon commutator according to claims 1 and 2, the carbon commutator obtained by the method according to claim 3 prevents the melting of the brazing material when the carbon commutator is incorporated into the rotor, and is more reliable. It is highly probable.

  The carbon commutator according to the present invention is formed of a carbon material having a bending strength and hardness equivalent to that of the brush on the side sliding with the brush of the counterpart material, and a mixed material containing metal powder and carbon powder on the opposite side. Formed two-layered substantially disk-shaped carbon base, terminal fitting having terminals for joining the carbon base and anchoring a winding to be an electrical path from the brush as a counterpart to the rotor, and the carbon base and the terminal fitting After joining, the periphery and the lower part of the carbon base excluding the sliding surface and shaft insertion hole are covered, and the joined carbon base, terminal fitting, and lower part of the terminal fitting are divided into a plurality of segments and electrically insulated. After being obtained, it is made of an insulating heat-resistant resin that serves as a support base for maintaining the shape of the commutator.

  In the present invention, there is no particular limitation on the bonding of the carbon base and the terminal fitting, but from the viewpoint of ease of work and reliability of the bonding and manufacturing cost, it can be bonded using a conductive paste, brazing material, Among these, it is preferable to join using a brazing material. When joining using brazing material, as shown above, the side to be connected to the carbon-based terminal fitting is made of a mixed material containing metal powder and carbon powder, resulting in superior joining strength and voltage drop. Fewer carbon commutators can be obtained.

The bending strength and the Shore hardness of the layer forming the carbon material used in the present invention are not particularly limited, but the bending strength is preferably in the range of 5 MPa to 50 MPa, more preferably in the range of 10 MPa to 40 MPa, and 15 MPa to 30 MPa. The range of is more preferable.
On the other hand, the Shore hardness is preferably in the range of 7 to 50, more preferably in the range of 10 to 40, and still more preferably in the range of 15 to 35.

The linear expansion coefficient of the layers forming a mixed material used in the present ^{invention, 6.0 × 10 -6 /K~18.0×10 -6 /} K, preferably 10.0 × ¹⁰ -6 / K ~17.0 ^-6 / K, more preferably ^{12.0 -6 /K~17.0} -6 / K or in the range of is required, the linear expansion coefficient of 6.0 × ¹⁰ -6 / K If it is less than 1, the crack reducing effect is small, and if it exceeds 18.0 × 10 ⁻⁶ / K, the carbon material layer is not sufficiently fixed, and peeling may occur near the boundary between the two.
In addition, said bending strength and a linear expansion coefficient are the values measured by the measuring method according to JIS-R7212, and Shore hardness is the value measured using Nakai Seiki Seisakusho D type Shore hardness meter.

  The brazing material used for joining the carbon base and the terminal metal fitting is not particularly limited, but preferred brazing materials include JIS-Z3261, JIS-Z3262, JIS-Z3263, JIS-Z3264, JIS-Z3265, and JIS-Z3266. Copper brazing, brass brazing, silver brazing, phosphoric copper brazing, titanium brazing, nickel brazing, aluminum brazing, copper brazing containing titanium, and the like, and these brazing materials are generally described in JIS-Z3267. It is brazed using a flux.

  The blending ratio of the metal powder in the mixed material containing the metal powder and carbon powder is preferably in the range of 15% by weight to 85% by weight, more preferably in the range of 30% by weight to 85% by weight, and 60% by weight. The range of% to 80% by weight is more preferable. When the mixing ratio of the metal powder exceeds 85% by weight, the ratio of the carbon powder relatively decreases depending on the constituent elements of the metal powder to be used, the particle diameter and the particle shape. Adhesion with the carbon material on the side becomes insufficient, and peeling tends to occur near the boundary between the carbon material layer (hereinafter referred to as carbon material layer) and the mixed material layer (hereinafter referred to as mixed material layer). . On the other hand, if the blending ratio of the metal powder is less than 15% by weight, although depending on the constituent elements, particle diameter and particle shape of the metal powder to be used, the bonding between the metal powders becomes insufficient and the mixed material layer itself becomes brittle. Tend to be difficult to handle.

  There are no particular restrictions on the type of metal powder used in the above-mentioned mixed material, but for example, simple substances such as gold, silver, copper, aluminum, iron, nickel, chromium, molybdenum, tungsten, palladium, magnesium, zinc, tin, titanium, etc. Or 2 or more types of alloys can be used as a preferable thing. In addition, the above metal powder can be used alone or in combination of two or more. There is no limitation on the production method and shape of the metal particles, gas atomization method, high pressure water atomization method, mechanical pulverization method, REP method, rotating disk method, electrolytic method, etc. Granular and fibrous shapes can be used.

  However, carbon or brass is generally used for the terminal fitting of the carbon commutator. For the purpose of improving the corrosiveness against copper powder, alcohol-added fuel or high-sulfur fuel, copper is the main component and gold is used. Silver, nickel, chromium, manganese, zinc, tin, titanium, or any one of two or more mixed powders or alloy powders are preferably used. In this case, the mixing ratio other than copper may be appropriately selected in consideration of the linear expansion coefficient of the mixed material layer, the bondability with the brazing material to be used, the bonding strength, the productivity, the cost, and the like.

  As a material constituting the carbon base, as a carbon material (powder) used for a carbon material and a mixed material that slides with a mating brush, for example, one kind selected from natural graphite, artificial graphite, coke, mesophase or the like Two or more kinds of fillers are used, and pitch, tar, creosote, novolac type phenol resin, resol type phenol resin, furan resin, etc. are appropriately used as binders, and these are uniformly made by known methods such as kneading and sheet molding. It can be used after being mixed and subjected to treatment such as pulverization, mixing, and classification as required.

  For kneading or molding powder, additives such as talc, molybdenum disulfide, carbon fiber, glassy carbon powder, coke powder, carbon black, mesophase powder, fullerenes, carbon nanotubes or the like as necessary A mold release agent or the like may be added as appropriate for preventing mold adhesion. The obtained carbon material molding powder is molded into a two-layer structure using a mechanical press, a hydraulic press, etc. together with the molding powder as a mixed material obtained by mixing with metal powder, and then in vacuum, Baking in a non-oxidizing atmosphere using an active gas, a reducing gas, or the like.

  The firing temperature may be determined by taking into consideration the characteristics required of the carbon material as a fuel pump, the brazing temperature of the carbon base and the terminal fitting, etc., but the binder used as the raw material for the carbon material is converted from organic to carbonized. A temperature of 500 ° C. or higher is desirable. The upper limit of the firing temperature is the upper limit of the melting point of the metal powder used for the carbon-based mixed material. When firing above the melting point of the metal powder, the metal may be dissolved and the shape cannot be maintained. If the firing temperature to obtain the characteristics required for carbon materials as a fuel pump is equal to or higher than the brazing temperature, the metal powder used in the carbon-based mixed material can be changed to one with a high melting point to support brazing. It becomes possible to do.

The carbon commutator obtained by the present invention is incorporated in a rotor, and the winding is connected to the terminal fitting of the carbon commutator. At that time, heat of connection fusing is usually applied. Since the heat of connection fusing is transferred to the brazing material through the terminal fitting, when the melting point of the brazing material used for joining the carbon base and the terminal fitting is low, the brazing material is melted by this heat, and the carbon and terminals divided into segments The metal fittings may come off. If the joint between the carbon material and the terminal fitting peels off, in the worst case, the brush serving as the mating material will be caught by the trace of the carbon piece divided into segments, the rotor will stop, and the fuel pump will not operate There is a fear.
For this reason, the brazing material used for joining the carbon base and the terminal fitting is preferably one having a melting point of 500 ° C. or higher, more preferably 550 ° C. or higher, further preferably 600 ° C. or higher. Most preferably, it is below the firing temperature.

The carbon commutator of the present invention obtained in this way is used as a motor for a fuel pump of an automobile after the carbon base and the terminal metal fitting are simply and highly reliable and incorporated in the rotor. Is done.
In addition, the carbon commutator obtained by the present invention has a carbon base having a two-layer structure of a carbon material layer and a mixed material layer, and the linear expansion coefficient is brought close to the linear expansion coefficient of the terminal fitting, so that The cracks that occur near the boundary of the terminal fitting can be prevented, so there is no need to increase the strength of the carbon base in order to prevent cracking during joining as in the past, and the motor efficiency of the fuel pump and long-term use Carbon-based materials against wear and tear, design constraints can be virtually eliminated.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a carbon commutator according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of FIG.
Example 1
Natural graphite (manufactured by Nippon Graphite Industry Co., Ltd., trade name CB-100) is used as a filler as a carbon material on the sliding side of the mating material, and furan resin (Hitachi Chemical Industries, Ltd.) is used as a binder in 70% by weight of the natural graphite. (Product name, VF-302) 30% by weight was weighed, and methanol as a solvent was blended at a ratio of 30% by weight with respect to the binder and kneaded at 50 ° C. for 30 minutes. After kneading and drying at 90 ° C. for 6 hours, the particle size was pulverized to 20 μm or less with an impact pulverizer to obtain a molding powder of carbon material.

  On the other hand, 75% by weight of bronze powder obtained by the atomizing method (trade name L89N, manufactured by Nippon Atomizing Co., Ltd.) and 25% by weight of the molding powder of the carbon material obtained above were stirred and mixed in a V-type blender. A molding powder was obtained. Thereafter, a die having an outer diameter of 20 mm (φ) and an inner diameter of 10 mm (φ) is attached to the mechanical press so that the thickness of the mixed material layer after molding is 1 mm and the thickness of the carbon material layer is 3 mm. After filling the mold with the molding powder of the mixed material, the surface of the filling powder is leveled using a jig, and then the molding powder of the carbon material is filled and pressurized under the condition of 400 MPa to form a two-layer carbon. A base molded product was obtained.

The two-layered carbon base molded product obtained above was heated to 700 ° C. at a heating rate of 50 ° C. for 1 hour in a reducing gas atmosphere with decomposed ammonia gas, held at 700 ° C. for 1 hour, and then cooled. A carbon base 3 having a carbon material layer 1 and a mixed material layer 2 was obtained.
On the other hand, test pieces (size, thickness 4 mm × width 4 mm × length 25 mm) of only the carbon material layer and the mixed material layer were respectively produced using the same molding powder as above, and the bending strength and shore of the carbon material layer were produced. While measuring hardness, the linear expansion coefficient of the mixed material layer was measured, respectively. As a result, the bending strength of the carbon material layer was 25 MPa and the Shore hardness was 18. The linear expansion coefficient of the mixed material layer was 13.3 × 10 ⁻⁶ K.

  Next, the carbon base 3 obtained above and a copper terminal fitting 4 having an outer diameter of 20 mm (φ) and an inner diameter of 19 mm (φ) are silver brazed (JIS Z-3261, BAg−) having a width of 1 mm and a melting point of 620 ° C. 1), brazing was performed at a temperature of 650 ° C. in a reducing gas atmosphere with decomposed ammonia gas, and the carbon base 3 and the terminal fitting 4 were joined. Although the vicinity of the boundary between the carbon base 3 and the terminal metal fitting 4 after joining was visually observed using a magnifying glass having a magnification of 3 times, no cracks were generated.

  Thereafter, by injection molding, a phenol resin (manufactured by Hitachi Chemical Co., Ltd.) with 40% by weight of glass short fibers added to the sliding surface of the carbon base 3 and the periphery and the lower portion of the carbon base 3 excluding the shaft insertion hole 5 is used. In the product name CP-7320), molding is performed under the conditions of a molding temperature of 180 ° C. and a molding pressure of 150 MPa, and then the carbon base 3, the terminal fitting 4 and the molding portion 6 to the lower part of the terminal fitting are divided into adjacent portions. Obtained a carbon commutator having 8 segments each insulated. In FIG. 1, 7 is a dividing groove and in FIG. 2, 8 is a terminal.

Example 2
15% by weight of electrolytic copper powder (trade name CE25, manufactured by Fukuda Metal Co., Ltd.) obtained by the electrolysis method, 5% by weight of bronze powder (trade name L89N, manufactured by Nippon Atomization Co., Ltd.) obtained by the atomization method, and 80% by weight of the carbon material molding powder obtained in Example 1 was stirred and mixed with a V-type blender to obtain a molding powder of the mixed material. Using this mixed material molding powder and the carbon material molding powder obtained in Example 1, a carbon base having a two-layer structure was obtained through the same steps as in Example 1. Moreover, when the same test piece as Example 1 was produced using the molding powder of the mixed material obtained above, and the linear expansion coefficient of the mixed material layer was measured, it was 6.9 × 10 ⁻⁶ / K.

  Next, through the same steps as in Example 1, the carbon base obtained above and the terminal fitting used in Example 1 were brazed, and the carbon base and the terminal fitting were joined. The vicinity of the boundary between the carbon base and the terminal fitting after joining was visually observed using a magnifying glass with a magnification of 3 ×, but no crack was generated. A carbon commutator having the same shape as in Example 1 was obtained through the same steps as in Example 1 below.

Comparative Example 1
Using only the molding powder of the carbon material obtained in Example 1, a carbon base having a thickness of 4 mm was obtained through the same steps as in Example 1. Moreover, the test piece similar to Example 1 was produced using the molding powder of the carbon material obtained above, and the bending strength and Shore hardness of the carbon material layer were measured. As a result, the bending strength was 25 MPa and the Shore hardness was 18. The carbon base obtained above through the same steps as in Example 1 and the terminal fitting used in Example 1 were brazed to join the carbon base and the terminal fitting. When the vicinity of the boundary between the bonded carbon base and the terminal fitting was visually observed with a magnifying glass having a magnification of 3 times, a crack was generated.

Comparative Example 2
17% by weight of bronze powder obtained by the atomizing method (manufactured by Nippon Atomizing Co., Ltd., trade name L89N) and 83% by weight of the carbon material powder obtained in Example 1 were stirred and mixed using a V-type blender. A molding powder of the mixed material was obtained. Using this mixed material molding powder and the carbon material molding powder obtained in Example 1, a carbon base having a two-layer structure was obtained through the same steps as in Example 1. Moreover, when the same test piece as Example 1 was produced using the molding powder of the mixed material obtained above, and the linear expansion coefficient of the mixed material was measured, it was 5.6 × 10 ⁻⁶ / K. The carbon base obtained above through the same steps as in Example 1 and the terminal fitting used in Example 1 were brazed to join the carbon base and the terminal fitting. When the vicinity of the boundary between the bonded carbon base and the terminal fitting was visually observed with a magnifying glass having a magnification of 3 times, a crack was generated.

Reference example 1
Bronze powder obtained by the atomizing method (manufactured by Nippon Atomizing Co., Ltd., trade name L89N)
90% by weight and 10% by weight of the carbon material molding powder obtained in Example 1 were mixed with stirring using a V-type blender to obtain a molding powder of the mixed material. The mixed material molding powder and the carbon material molding powder obtained in Example 1 were used to obtain a two-layered carbon base through the same steps as in Example 1, but after molding, the carbon material layer and Separation occurred between the mixture layers, and a two-layer carbon base was not obtained.

  In addition, although the said Example demonstrated the example applied to the planar carbon commutator for fuel pumps, the carbon commutator obtained by this invention is effective also with respect to a cylindrical carbon commutator. At the same time, not only for fuel pump applications, but also to meet the characteristics required for carbon materials and to improve the reliability of carbon and metal fittings, we manufacture carbon commutators that can be applied in any field. It is possible.

It is a top view of the carbon commutator which becomes an example of the present invention. It is sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Carbon material layer 2 Mixed material layer 3 Carbon base 4 Terminal metal fitting 5 Shaft insertion hole 6 Mold part 7 Dividing groove 8 Terminal

Claims (3)

In the method of manufacturing a carbon commutator having a carbon base and a terminal metal fitting connected to the carbon base, the side sliding with the brush of the mating member is formed of carbon material, while the side connecting to the terminal metal fitting is made of metal powder and carbon It comprises flour, and to prepare a carbon-based form the two-layer structure in admixture with a linear expansion coefficient of ^{6.0 × 10 -6 /K~18.0×10 -6 / K} , then the carbon-based and terminal The metal base is joined with a brazing material , and then the carbon base is fixed by molding the resin base around the carbon base sliding surface and the shaft insertion hole except for the shaft insertion hole, and then fixing the carbon base. Carbon rectification characterized by dividing the mold part up to the lower part of the metal fitting into multiple parts and forming multiple segments where the adjacent parts are electrically insulated from each other Method of production.   The method for producing a carbon commutator according to claim 1, wherein the mixed material containing metal powder and carbon powder contains metal powder in the range of 15 wt% to 85 wt% with respect to the mixed material. The method for producing a carbon commutator according to claim 1 or 2, wherein the carbon base and the terminal fitting are joined electrically and mechanically using a brazing material having a melting point of 500 ° C or higher.

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