CN111009804A - Preparation method of copper-graphite composite electric brush - Google Patents
Preparation method of copper-graphite composite electric brush Download PDFInfo
- Publication number
- CN111009804A CN111009804A CN201911231678.XA CN201911231678A CN111009804A CN 111009804 A CN111009804 A CN 111009804A CN 201911231678 A CN201911231678 A CN 201911231678A CN 111009804 A CN111009804 A CN 111009804A
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- copper
- powder
- graphite
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- ball milling
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R43/00—Apparatus or processes specially adapted for manufacturing, assembling, maintaining, or repairing of line connectors or current collectors or for joining electric conductors
- H01R43/12—Manufacture of brushes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
- B22F7/02—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite layers
Abstract
The invention relates to a preparation method of a copper-graphite composite electric brush, which is characterized in that the structural components of a brush body of the electric brush are optimized, a working layer of the brush body is made of a material with high content of graphite, and a lead-out wire end is made of a pure copper material, so that the wear resistance of the brush body can be ensured, the connection resistance between the brush body and the lead-out wire can be reduced, and the yield of the electric brush in production and preparation can be improved.
Description
Technical Field
The invention belongs to the field of preparation of small aviation electric brush elements, and particularly relates to a preparation method of a copper-graphite composite electric brush.
Background
The small aviation electric brush is mainly applied to special environments with narrow space size, long replacement period and severe environmental use. The electric brush working in the environment is required to have excellent conductivity, small size, good lubricating property, less brush body abrasion and long service life. Because the thickness of the brush body of the electric brush is only 2-5 mm, a hole 5 (the aperture phi is 1-3 mm) needs to be drilled on the end face of the brush body 5, and a conductive leading-out wire (shown in figure 2) is installed, so that the thickness of the weakest part after drilling is usually less than 1 mm. In addition, the brush body is usually of a graphite or copper-graphite composite structure, so that the brush body is soft in texture and low in hardness (less than 30 HBS), cracks or fractures easily occur in punching, and the yield is low. During later assembly, in order to reduce the connection resistance between the outgoing line and the brush body, larger external force is needed to compact and fill powder, and the hole wall is easy to crack in the extrusion process, so that the waste is caused.
The brush belongs to the consumptive material, and the aviation brush body material of adopting in domestic often is graphite (the wearing and tearing value is less than 0.015 mm/h), need change after using 200~300h, extravagant manpower and materials. And the volume resistance of the graphite electric brush is large, and the power loss on the brush body is serious.
Disclosure of Invention
The invention aims to provide a preparation method of a copper-graphite composite electric brush, which is characterized in that the structural components of an electric brush body are optimized, a working layer of the brush body is made of a material with high content of graphite, and a lead-out wire end is made of a pure copper material, so that the wear resistance of the brush body can be ensured, the connection resistance between the brush body and the lead-out wire can be reduced, and the yield of the electric brush in production and preparation can be improved.
The technical scheme of the invention is as follows:
the preparation method of the copper-graphite composite electric brush comprises the following steps:
1) ingredients
Taking copper-plated graphite powder and pure copper powder, and respectively preparing transition layer mixed powder B containing 5-20% of graphite and working layer mixed powder A containing 30-60% of graphite;
2) mixing material
Respectively filling the mixed powder A, B into respective ball milling tanks, respectively adding the mixed powder A, B into the respective ball milling tanks according to 30-50% of the mixed powder A, B by weight, introducing argon to remove air, introducing 3-5L/min of argon flow, sealing the ball milling tanks after introducing the argon flow for 10-20 min, and mixing the materials to obtain mixed powder A1 and B1;
3) pretreatment of
Taking out the mixed powders A1 and B1, and respectively reducing A1 and B1 in a furnace in a hydrogen atmosphere; reducing the pure copper powder C in a furnace in a hydrogen atmosphere to respectively obtain A2, B2 and C2;
4) shaping of
Sieving the treated powder with a 60-120-mesh sieve to obtain A2, B2 and C2; taking A2, B2 and C2 according to the proportion of the brush body components, sequentially filling the working layer, the transition layer and the pure copper powder into a die, and performing compression molding; sintering into blank under vacuum condition, heating for the second stage, and cooling along with the furnace;
5) finished product
And cutting the blank into a blank, cleaning, drying and assembling to obtain the copper-graphite composite electric brush product.
Step 1), the granularity of the copper-plated graphite powder is 5-30 mu m, and the mass fraction of graphite is 70-80%; the granularity of the pure copper powder is 5-30 mu m.
And 2) the argon flow is 3-5L/min.
And 2) mixing the materials at a rotating speed of 120-180 r/min for 8-20 h.
And 2) the ball milling tank is a pure copper ball milling tank.
The reduction treatment conditions in the step 3) are as follows: the hydrogen flow is 5-10L/min, the temperature is 200-400 ℃, and the heat preservation time is 20-50 minutes.
And 4) pressing at 3-8 Mpa for 5-20S.
And step 4) the brush body comprises 30 percent of A2 component, 10 percent of B2 component and 60 percent of C2 component.
Step 5), the second-stage heating comprises the following steps: heating the mixture to 200-400 ℃ at the room temperature, wherein the heating speed is 5-10 ℃/min, and the heat preservation time is 0.5-1 h; and then heating to 750-900 ℃, wherein the heating speed is 10-20 ℃/min, and the heat preservation time is 2 h.
Positive effects of the invention
(1) The copper content of the joint part of the electric brush body and the copper stranded wire prepared by the invention is high (or pure copper), so the joint resistance between the electric brush body and the copper stranded wire is low, and is usually below 2m omega;
(2) the experiment of the applicant proves that the compression strength of the electric brush is more than 240Mpa, the density is more than 97 percent, and the resistivity is less than 5 omega.m (the compression strength of the common electric brush body is less than 190Mpa, the density is less than 90 percent, and the resistivity is more than 7 omega.m), so that the electric brush body prepared by the invention has the advantages of good strength, high density, excellent wear resistance, long service life, low integral resistance of the brush body and small loss in the power and signal transmission process.
(3) The method of the present invention can also be used for preparing 4 or more components of gradient material composite electric brushes, and the components of the electric brushes can also be expanded to silver-graphite and silver-copper-graphite materials. The content of each component can also be adjusted according to actual requirements.
Drawings
FIG. 1 is a schematic view of the brush of the present invention;
FIG. 2 is a schematic view of a prior art brush;
FIG. 3 is a brush blank obtained by the method described in example 1;
fig. 4 shows a brush blank obtained by the method described in example 2.
Detailed Description
Example 1 a gradient copper graphite metal brush was prepared having a working layer containing 60% copper, a transition layer containing 80% copper, and a lead terminal of pure copper
Weighing 2kg of copper-plated graphite powder with 20% of copper content, adding 2kg of copper powder to prepare working layer mixed powder A with 60% of copper, and adding 4kg of the working layer mixed powder A; weighing 1kg of copper-plated graphite powder with 20% of copper content, adding 3kg of copper powder to prepare working layer mixed powder B with 80% of copper, and adding 4kg of copper-plated graphite powder;
a, B are respectively put into different pure copper ball milling tanks, copper grinding balls are respectively added according to the proportion of 50 percent of the weight of the mixed powder, wherein 2kg of copper grinding balls are added into the pure copper ball milling tank filled with the mixed powder A, 2kg of copper grinding balls are added into the pure copper ball milling tank filled with the mixed powder B, argon is introduced to remove air, the flow of the argon is 5L/min, the ball milling tank is sealed after 20min of air introduction according to the volume of the ball milling tank. The mixing speed is 180r/min, and the mixing time is 20 h.
And taking out the mixed powder, and respectively carrying out reduction treatment in a furnace in a hydrogen atmosphere at the flow rate of 10L/min and the temperature of 400 ℃ for 250 minutes. After the powder was cooled, it was sieved through a 60 mesh sieve.
And respectively loading the powder into a die according to the sequence of the working layer, the transition layer and the pure copper powder. Pressing by an oil press, wherein the pressing pressure is 8Mpa, and the pressure maintaining time is 20S. Sintering the green compact in a vacuum furnace, heating the green compact to 400 ℃ from room temperature by adopting 2 sections of heating, heating at a speed of 10 ℃/min, keeping the temperature for 0.1h, heating to 900 ℃ again, heating at a speed of 20 ℃/min, keeping the temperature for 2h, and cooling along with the furnace to obtain an electric brush blank (referring to figure 3, three layers of an electric brush can be obviously seen); cutting the sintered blank into required size (distinguishing working end and leading-out wire end); cleaning the cut blank with kerosene, and drying; punching the end of the outgoing line of the brush body by using a drill, removing scraps, filling a copper stranded wire, and filling high-temperature conductive adhesive in a gap; and drying according to the drying requirement of the conductive adhesive product.
The structure of the electric brush is shown in fig. 2, the brush body is of a 3-layer structure, the uppermost layer is a copper base body 2 and is used for installing (or welding or screw connection) an electric brush outgoing line 1; the intermediate layer is a transition layer 3 made of a copper and graphite composite material (with more copper content) and used for connecting the copper matrix and the lower working part; the bottom layer is a working layer 4 made of a copper and graphite composite material (with more graphite content), and is in contact with the conductive ring to play a role in lubrication and conduction.
Example 2 a gradient copper graphite metal brush was prepared with 50% copper in the working layer, 70% copper in the transition layer, and pure copper at the lead-out end
Weighing 2kg of copper-plated graphite powder with 20% of copper content, adding 1.2kg of copper powder to prepare working layer mixed powder A with 50% of copper, and adding 3.2kg of the working layer mixed powder A; weighing 1kg of copper-plated graphite powder with 20% of copper content, adding 1.7kg of copper powder to prepare working layer mixed powder B with 70% of copper, wherein the total amount is 2.7 kg;
a, B are respectively put into different pure copper ball milling tanks, copper grinding balls are respectively added according to the proportion of 50 percent of the weight of the mixed powder, wherein, 1.6kg of copper grinding balls are added into the pure copper ball milling tank filled with the mixed powder A, 1.35kg of copper grinding balls are added into the pure copper ball milling tank filled with the mixed powder B, argon is introduced to remove air, the flow of the argon is 5L/min, the ball milling tank is sealed after 20min of air introduction is carried out according to the volume of the ball milling tank. The mixing speed is 180r/min, and the mixing time is 20 h.
And taking out the mixed powder, and respectively carrying out reduction treatment in a furnace in a hydrogen atmosphere at the flow rate of 10L/min and the temperature of 400 ℃ for 250 minutes. And after the powder is cooled, sieving the powder by a 60-mesh sieve to obtain the powder.
The powder is loaded into a die according to the sequence of a working layer A2, a transition layer B2 and pure copper powder C2. Pressing by an oil press, wherein the pressing pressure is 8Mpa, and the pressure maintaining time is 20S. Sintering the pressed compact in a vacuum furnace, heating from room temperature to 400 ℃ by adopting 2 sections of heating, heating at a speed of 10 ℃/min, keeping the temperature for 0.1h, heating to 900 ℃, heating at a speed of 20 ℃/min, keeping the temperature for 2h, and cooling along with the furnace; obtaining a brush blank (see fig. 4, it is obvious that the brush has three layers); cutting the sintered blank into required size (distinguishing working end and leading-out wire end); cleaning the cut blank with kerosene, and drying; punching the end of the outgoing line of the brush body by using a drill, removing scraps, filling a copper stranded wire, and filling high-temperature conductive adhesive in a gap; and drying according to the drying requirement of the conductive adhesive product.
The structure of the electric brush is shown in fig. 2, the brush body is of a 3-layer structure, the uppermost layer is a copper base body 2 and is used for installing (or welding or screw connection) an electric brush outgoing line 1; the intermediate layer is a transition layer 3 made of a copper and graphite composite material (with more copper content) and used for connecting the copper matrix and the lower working part; the bottom layer is a working layer 4 made of a copper and graphite composite material (with more graphite content), and is in contact with the conductive ring to play a role in lubrication and conduction.
Claims (9)
1. A preparation method of a copper-graphite composite electric brush is characterized by comprising the following steps:
1) ingredients
Taking copper-plated graphite powder and pure copper powder, and respectively preparing transition layer mixed powder B containing 5-20% of graphite and working layer mixed powder A containing 30-60% of graphite;
2) mixing material
Respectively filling the mixed powder A, B into respective ball milling tanks, respectively adding the mixed powder A, B into the respective ball milling tanks according to 30-50% of the mixed powder A, B by weight, introducing argon to remove air, introducing 3-5L/min of argon flow, sealing the ball milling tanks after introducing the argon flow for 10-20 min, and mixing the materials to obtain mixed powder A1 and B1;
3) pretreatment of
Taking out the mixed powders A1 and B1, and respectively reducing A1 and B1 in a furnace in a hydrogen atmosphere; reducing the pure copper powder C in a furnace in a hydrogen atmosphere to respectively obtain A2, B2 and C2;
4) shaping of
Sieving the treated powder with a 60-120-mesh sieve to obtain A2, B2 and C2; taking A2, B2 and C2 according to the proportion of the brush body components, sequentially filling the working layer, the transition layer and the pure copper powder into a die, and performing compression molding; sintering into blank under vacuum condition, heating for the second stage, and cooling along with the furnace;
5) finished product
And cutting the blank into a blank, cleaning, drying and assembling to obtain the copper-graphite composite electric brush product.
2. The method of claim 1, wherein: step 1), the granularity of the copper-plated graphite powder is 5-30 mu m, and the mass fraction of graphite is 70-80%; the granularity of the pure copper powder is 5-30 mu m.
3. The method of claim 1, wherein: and 2) the argon flow is 3-5L/min.
4. The method of claim 1, wherein: and 2) mixing the materials at a rotating speed of 120-180 r/min for 8-20 h.
5. The method of claim 1, wherein: and 2) the ball milling tank is a pure copper ball milling tank.
6. The method according to claim 1, wherein the reducing treatment in step 3) is performed under the following conditions: the hydrogen flow is 5-10L/min, the temperature is 200-400 ℃, and the heat preservation time is 20-50 minutes.
7. The method of claim 1, wherein: and 4) pressing at 3-8 Mpa for 5-20S.
8. The method of claim 1, wherein: and step 4) the brush body comprises 30 percent of A2 component, 10 percent of B2 component and 60 percent of C2 component.
9. The method according to claim 1, wherein the secondary heating in step 5) is: heating the mixture to 200-400 ℃ at the room temperature, wherein the heating speed is 5-10 ℃/min, and the heat preservation time is 0.5-1 h; and then heating to 750-900 ℃, wherein the heating speed is 10-20 ℃/min, and the heat preservation time is 2 h.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911231678.XA CN111009804A (en) | 2019-12-05 | 2019-12-05 | Preparation method of copper-graphite composite electric brush |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911231678.XA CN111009804A (en) | 2019-12-05 | 2019-12-05 | Preparation method of copper-graphite composite electric brush |
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| CN111009804A true CN111009804A (en) | 2020-04-14 |
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| CN201911231678.XA Pending CN111009804A (en) | 2019-12-05 | 2019-12-05 | Preparation method of copper-graphite composite electric brush |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2737611C1 (en) * | 2020-06-25 | 2020-12-01 | Федеральное государственное автономное образовательное учреждение высшего образования "Российский университет транспорта" (ФГАОУ ВО РУТ (МИИТ), РУТ (МИИТ) | Manufacturing method of current conducting contact elements |
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|---|---|---|---|---|
| JPH0515114A (en) * | 1991-07-05 | 1993-01-22 | Nippondenso Co Ltd | Laminated brush |
| CN1330724A (en) * | 1998-12-16 | 2002-01-09 | 维多利亚铁路公司 | Low resisting materials with improved wear performance for electrical current transfer and methods for preparing same |
| CN201349084Y (en) * | 2008-09-19 | 2009-11-18 | 神奇电碳集团有限公司 | Multi-layer electric brush compounded from copper and graphite |
| CN106868335A (en) * | 2017-03-15 | 2017-06-20 | 上海法雷奥汽车电器***有限公司 | A kind of automobile starter carbon brush material and preparation method thereof |
| CN108512006A (en) * | 2017-02-24 | 2018-09-07 | 上海新池能源科技有限公司 | A kind of copper-graphite-graphene brush and preparation method thereof |
| CN109524866A (en) * | 2018-11-30 | 2019-03-26 | 大同新成新材料股份有限公司 | A kind of graphene-carbon nano-fiber enhancing copper-base graphite carbon brush for electric machine and preparation method thereof |
-
2019
- 2019-12-05 CN CN201911231678.XA patent/CN111009804A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0515114A (en) * | 1991-07-05 | 1993-01-22 | Nippondenso Co Ltd | Laminated brush |
| CN1330724A (en) * | 1998-12-16 | 2002-01-09 | 维多利亚铁路公司 | Low resisting materials with improved wear performance for electrical current transfer and methods for preparing same |
| CN201349084Y (en) * | 2008-09-19 | 2009-11-18 | 神奇电碳集团有限公司 | Multi-layer electric brush compounded from copper and graphite |
| CN108512006A (en) * | 2017-02-24 | 2018-09-07 | 上海新池能源科技有限公司 | A kind of copper-graphite-graphene brush and preparation method thereof |
| CN106868335A (en) * | 2017-03-15 | 2017-06-20 | 上海法雷奥汽车电器***有限公司 | A kind of automobile starter carbon brush material and preparation method thereof |
| CN109524866A (en) * | 2018-11-30 | 2019-03-26 | 大同新成新材料股份有限公司 | A kind of graphene-carbon nano-fiber enhancing copper-base graphite carbon brush for electric machine and preparation method thereof |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2737611C1 (en) * | 2020-06-25 | 2020-12-01 | Федеральное государственное автономное образовательное учреждение высшего образования "Российский университет транспорта" (ФГАОУ ВО РУТ (МИИТ), РУТ (МИИТ) | Manufacturing method of current conducting contact elements |
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