WO2024122575A1 - Balai de carbone et cuivre - Google Patents

Balai de carbone et cuivre Download PDF

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Publication number
WO2024122575A1
WO2024122575A1 PCT/JP2023/043633 JP2023043633W WO2024122575A1 WO 2024122575 A1 WO2024122575 A1 WO 2024122575A1 JP 2023043633 W JP2023043633 W JP 2023043633W WO 2024122575 A1 WO2024122575 A1 WO 2024122575A1
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WO
WIPO (PCT)
Prior art keywords
copper
brush
value
carbon
mass
Prior art date
Application number
PCT/JP2023/043633
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English (en)
Japanese (ja)
Inventor
弘文 佐波
新太郎 道端
よし子 吉田
寛裕 小原
圭崇 北角
Original Assignee
トライス株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by トライス株式会社 filed Critical トライス株式会社
Publication of WO2024122575A1 publication Critical patent/WO2024122575A1/fr

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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
    • H01R39/00—Rotary current collectors, distributors or interrupters
    • H01R39/02—Details for dynamo electric machines
    • H01R39/04—Commutators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K13/00—Structural associations of current collectors with motors or generators, e.g. brush mounting plates or connections to windings; Disposition of current collectors in motors or generators; Arrangements for improving commutation

Definitions

  • This invention relates to a copper carbon brush that has a low copper content and excellent electrical conductivity.
  • Copper carbon brushes are used in motors, generators, etc., where the carbon, such as graphite, improves the sliding performance against commutators, slip rings, etc., while the copper increases the electrical conductivity. If a brush with high electrical conductivity can be obtained with a low copper content, the carbon content can be increased to improve the sliding performance. Furthermore, the copper in the brush exists in a form close to powder, and when it comes into contact with the copper of the commutator, slip ring, etc., it tends to adhere to each other, reducing the sliding properties.
  • the carbon such as graphite
  • Patent Document 1 JP 2020-5490 A discloses a brush for a high-current DC motor, which has two layers: a high-resistance layer for suppressing spark discharge and a low-resistance layer for ensuring conductivity, with the low-resistance layer containing a large amount of copper.
  • the low-resistance layer contains a large amount of copper.
  • a copper graphite brush contains, for example, 50 to 90 mass% copper to improve conductivity and reduce friction. This brush ensures conductivity by containing a large amount of copper.
  • the objective of this invention is to provide a copper graphite brush that has a low copper content and excellent electrical conductivity and sliding properties.
  • This invention is characterized by a copper-carbon brush containing copper and graphite, with a copper to carbon ratio of 20-60 mass% copper and 80-40 mass% total carbon, including graphite and carbon derived from binder resin, and an RGB value when the brush surface is imaged in an unpolished state, with the red component being 135 to 200, and the value ⁇ obtained by subtracting the blue component from the red component of the RGB value being 35 to 100.
  • the unpolished state refers to a state in which no polishing is performed after press molding and sintering.
  • the red component of the RGB value is between 145 and 200, and the value ⁇ obtained by subtracting the blue component from the red component of the RGB value is between 40 and 100.
  • the red component of the RGB value is between 150 and 200, and the value ⁇ obtained by subtracting the blue component from the red component of the RGB value is between 45 and 100.
  • the brush resistivity can be set to, for example, 500 ⁇ cm or less and 20 ⁇ cm or more. More preferably, the brush resistivity can be set to 200 ⁇ cm or less and 20 ⁇ cm or more.
  • the RGB value should be 145 or more and 200 or less for the red component, and the value ⁇ obtained by subtracting the blue component from the red component of the RGB value should be 40 or more and 100 or less.
  • the experiments were conducted with copper at 40 mass% and total carbon at 60 mass%, so the ratio of copper to carbon is, for example, 30-50 mass% copper and 70-50 mass% total carbon.
  • the inventors discovered that even if the copper content of the brush is the same, the conductivity of the brush increases when the value of the Red component of the RGB value is large and the value ⁇ obtained by subtracting the Blue value from the Red value is large.
  • the brush resistivity can be reduced to 500 ⁇ cm or less when the Red component of the RGB value is 135 or more and ⁇ is 35 or more.
  • the brush resistivity can be reduced to 300 ⁇ cm or less when the Red component of the RGB value is 145 or more and ⁇ is 40 or more.
  • the brush resistivity can be reduced to 100 ⁇ cm or less when the Red component of the RGB value is 150 or more and ⁇ is 45 or more.
  • a low copper content reduces friction with commutators, slip rings, etc., and an increase in carbon content improves the sliding performance of the brush.
  • This invention provides a copper-carbon brush with high conductivity and high sliding performance. The effects are shown in Table 1 and Figure 2.
  • a high value of the Red component of the RGB value and a high ⁇ value are related to a low value of the Blue component. It is preferable for the value of the Blue component of the RGB value to be low, and it is particularly preferable for it to be below 110.
  • the brush contains powdered copper and graphite, bound together with a resin binder.
  • the graphite structure in the brush breaks down, and ground graphite powder appears on the brush surface. This makes the brush darker in color. Therefore, the RGB values of the brushes covered by this invention are those in an unpolished state.
  • Front view of the copper carbon brush of the embodiment A characteristic diagram showing the relationship between the RGB value R and the RGB value difference ⁇ Red-Blue and the brush resistivity for the copper carbon brushes of the embodiment and the comparative example. Flowchart showing how to measure RGB values
  • the manufactured copper-graphite brush 2 is shown in FIG. 1. 4 is the brush body, 6 is the sliding surface, and 8 is the lead wire.
  • the manufactured brush 2 had a length of 20 mm, a width of 10 mm, and a thickness of 5 mm, but the size is optional.
  • the binder may be a thermoplastic resin, and the type of graphite powder and copper powder is optional.
  • the brush 2 may contain a solid lubricant such as molybdenum disulfide powder, and an abrasive such as alumina powder.
  • a solid lubricant such as molybdenum disulfide powder
  • an abrasive such as alumina powder.
  • lead wires 8 is optional.
  • the use of the brush of this invention is optional, and since the brush has high conductivity, it is suitable for applications where a large current flows at high voltage, such as the main motor of an EV (electric vehicle) and a wind power generator.
  • the ratio of copper to carbon was varied from 10 to 60 mass% copper and 90 to 40 mass% carbon.
  • the average particle size of the carbon was varied in the range of 80 ⁇ m to 200 ⁇ m.
  • RGB values The measurement method for RGB values is shown in Figure 3.
  • the RGB values of the manufactured brush (not polished) are measured.
  • the color sample used is the Japan Paint Manufacturers Association's "Paint Standard Color Sample Book” (2021 edition), which corresponds to 10R5/14 (JIS-W-8301) of the Munsell color system. JIS specifies the RGB values of this color sample as R value 212, G value 66, and B value 10. Adjust the illuminance so that the illuminance on the color sample and brush is 500 lx ⁇ 10 (Step 1). Adjust the image analysis software (Image-J) built into the digital camera as necessary (Step 2) and take a picture of the color sample (Step 3).
  • Image-J image analysis software
  • the captured image of the color sample is processed using image analysis software (Image-J) to obtain the RGB values (Step 4). If the RGB values of the color sample are within the range of R value 212 ⁇ 20, G value 66 ⁇ 10, and B value 15 ⁇ 10, it is considered to be within the shooting conditions, and if they are outside this range, it is considered to be outside the shooting conditions. If it is outside the shooting conditions, execute steps 2 to 4 again to make the RGB values of the color sample fall within the conditions. After adjusting the image analysis software (Image-J) to fit within the shooting conditions, photograph the brush sample with the same digital camera at the same illuminance (step 5), and measure the RGB values of the copper-carbon brush using the adjusted image analysis software (step 6).
  • image analysis software Image-J
  • the resistivity of the copper-carbon brush was measured in the direction of pressure using the four-terminal method.
  • the resistivity in the direction perpendicular to the direction of pressure was lower.
  • the copper content in the brush body did not include the lead wires, and the brush body was crushed and dissolved in, for example, an aqueous solution of nitric acid, and the copper content was measured by chelate titration.
  • the carbon content in the brush was determined by weighing the insoluble portion in the aqueous solution of nitric acid, etc., as mentioned above.
  • the resistivity of the brush changed when the R value and ⁇ value of the RGB values of the brush were different. Also, even if the copper content was different, the resistivity of the brush was similar if the R value and ⁇ value of the RGB values were similar. In general, brushes with high R value and high ⁇ value of the RGB values had low resistivity, and brushes with low values had high resistivity. Since it was difficult to obtain a brush with sufficient conductivity with 10 mass% copper, the weight ratio of copper to total carbon was set to 20:80 to 60:40. This ratio is preferably 30:70 to 50:50.
  • Figure 2 shows the results for Examples 1 to 6 and Comparative Examples 1 to 4 when the copper content was standardized to 40 mass% (the total of carbon and graphite derived from the binder was 60 mass%).
  • the copper content was set to 30 mass% (the total of carbon and graphite derived from the binder was 70 mass%), and in Example 8, the copper content was set to 50 mass% (the total of carbon and graphite derived from the binder was 50 mass%).
  • the copper content is the same in Examples 1 to 6 and the Comparative Example.
  • the resistivity is 500 ⁇ cm or less in the Examples, whereas it is 1000 ⁇ cm or more in the Comparative Example. From Examples 1 to 8, it can be seen that when the R value of the RGB values is high and the ⁇ value is high, the resistivity of the brush decreases. In particular, in Examples 1 to 4, when the R value of the RGB values was 145 or more and the ⁇ value was 40 or more, the resistivity of the brush was 200 ⁇ cm or less. Also, in Examples 1 to 4, the Blue component of the RGB values was less than 110 (105 or less). Furthermore, when the R value of the RGB values was 150 or more and the ⁇ value was 45 or more (Examples 1, 2, and 4), the resistivity of the brush was 100 ⁇ cm or less.
  • Comparative Examples 1 to 4 the resistivity exceeded 1000 ⁇ cm, and in Comparative Examples 1 and 2, where the Red value of the RGB values was low and the ⁇ value was also low, the resistivity was 3000 ⁇ cm or higher. In Comparative Examples 3 and 4, the Red value of the RGB values was high, but the ⁇ value was low at less than 35, and the resistivity exceeded 1000 ⁇ cm. Furthermore, in the Comparative Examples, the values of the Blue component of the RGB values all exceeded 110.
  • the brush may contain, in addition to copper, graphite, and carbon derived from the binder, a metal sulfide solid lubricant such as molybdenum disulfide, or an abrasive material such as alumina.
  • a metal sulfide solid lubricant such as molybdenum disulfide
  • an abrasive material such as alumina.
  • the ratio of materials other than copper, graphite, and carbon derived from the binder in the brush is, for example, 10 mass% or less, preferably 6 mass% or less. In such a range, the metal sulfide solid lubricant and the abrasive material have little effect on the color tone of the brush and on the conductivity of the brush.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Motor Or Generator Current Collectors (AREA)

Abstract

Selon la présente invention, les proportions de cuivre et de carbone dans un balai de carbone sont définies de telle sorte que la proportion de cuivre est de 20 à 60 % en masse et la proportion totale de carbones comprenant du graphite et un carbone dérivé d'une résine liante est de 80 à 40 % en masse. Par rapport à la valeur RVB obtenue en prenant une image de la surface du balai dans un état non poli, le composant rouge est de 135 à 200 (inclus), et la valeur ∆ obtenue en soustrayant la composante bleue de la composante rouge de la valeur RVB est de 35 à 100 (inclus). Ce balai permet d'obtenir une conductivité élevée même si la teneur en cuivre est faible.
PCT/JP2023/043633 2022-12-06 2023-12-06 Balai de carbone et cuivre WO2024122575A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2022-194636 2022-12-06
JP2022194636 2022-12-06

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WO2024122575A1 true WO2024122575A1 (fr) 2024-06-13

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009148034A (ja) * 2007-12-12 2009-07-02 Denso Corp 回転電機用ブラシおよび回転電機

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009148034A (ja) * 2007-12-12 2009-07-02 Denso Corp 回転電機用ブラシおよび回転電機

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