WO2005025034A1 - Carbon brush - Google Patents

Abstract

A first carbon brush which comprises a graphite powder as a filler having a particle diameter distribution curve as determined by the laser diffraction method wherein an integrated value for the number of graphite particles having a particle diameter of 5 μm or less accounts for 10 % or less of the total particles, preferably 5 % or less; a second carbon brush which is the first carbon brush further wherein an integrated value for the number of graphite particles having a particle diameter of 100 μm or more accounts for 10 % or less; a third carbon brush which is the second carbon brush further wherein an integrated value for the number of graphite particles having a particle diameter of 10 to 40 μm accounts for 60 % or more; a forth carbon brush which is the third carbon brush further wherein an integrated value for the number of graphite particles having a particle diameter of 12 to 20 μm accounts for 40 % or more.

Description

Carbon brush technical field

 The present invention relates to a carbon brush for an electric machine using a graphite particle filler, and more particularly to a carbon brush which suppresses particle detachment of the filler during use. Akita

Background art

 Conventionally, carbon brushes have been known. For example, there is one disclosed in Japanese Patent Application Laid-Open No. 2000-19973. In this document, artificial graphite particles or natural graphite particles were used as the filler. Since artificial black forceps particles or natural graphite particles, which are used as fillers, were roughly controlled and used as fine powder, coarse powder, etc., the resulting carpump brush had a non-uniform filler structure. Non-uniform ones with irregular sizes were the mainstream.

 However, in recent years, the motor input has increased, and the use conditions of carbon brushes have become severe. In such a case, in the case of the above-mentioned literature, particle detachment occurs at the time of use, and the life may be shortened. Therefore, an object of the present invention is to provide a carbon brush with a long life, in which the filler structure of the graphite particle filler is made uniform and the graphite particle filler is used. Disclosure of the invention

In order to solve the above-mentioned problems, the present inventors have conducted intensive studies and as a result, in order to prolong the life of carbon brush, a filter having a controlled particle size distribution is required. Carbon brush

Technical field

 The present invention relates to a carbon brush for an electric machine using a graphite particle filler, and in particular, to a carbon brush which suppresses particle detachment of the filler during use.

It is about Shi. Food

Background art

 Conventionally, carbon plush has been known. For example, there is one disclosed in Japanese Patent Application Laid-Open No. 2000-19973. In this document, artificial graphite particles or natural graphite particles were used as the filler. The artificial graphite particles or natural graphite particles used as the filler were roughly controlled and used as fine powder, coarse powder, etc., so the carpump formed was not uniform in the structure of the boiler. Non-uniform ones with irregular sizes were the mainstream.

 However, in recent years, the motor input has increased, and the use conditions of carbon brushes have become severe. In such a case, in the case of the above-mentioned literature, particle detachment occurs at the time of use, and the life may be shortened. Accordingly, an object of the present invention is to provide a carbon brush having a long lifetime, in which the filler structure of the graphite particle filler is made uniform and the black 10 particle filler is used. Disclosure of the invention

In order to solve the above-mentioned problems, the present inventors have conducted intensive studies and as a result, in order to prolong the life of carbon brush, a filter having a controlled particle size distribution is required. It has been found that it is extremely important to use graphite particles, and the present invention has been completed. That is, in the carbon brush according to the present invention, in the particle size distribution when graphite particles serving as a filter were measured by a laser diffraction method, the integrated value of graphite particles having a particle size of 5 IX m or less among graphite particles was 1 0% or less. Brief Description of Drawings

 FIG. 1 is a graph showing an example of a particle size distribution, FIG. 2 is a graph showing another example of a particle size distribution, and FIG. 3 is a table showing characteristics of examples and comparative examples of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

 In the particle size distribution when the graphite particles serving as fillers were measured by a laser diffraction method, the integrated value of the graphite particles having a particle size of 5 μm or less among the graphite particles was 10% or less, preferably 5% or less. Yes, and the integrated value of graphite particles with a particle diameter of 100 μm or more among graphite particles is 10% or less, and the integration of graphite particles with a particle diameter of 10 to 40 μm among graphite particles The value is controlled to be 60% or more of the whole, and among them, the graphite particles having a particle diameter of 12 to 20 are controlled to be 40% or more. As a result, the structure of the graphite particles forming the filler becomes uniform. For this reason, in the carbon brush using the graphite particle filler, even if the particle detachment occurs during use, the detached particle portion is small, and the life extension effect can be obtained.

 Here, the principle of the laser diffraction method will be described. When laser light (monochromatic, parallel beam) is applied to the particles to be measured, a spatially diffracted and scattered light intensity distribution pattern is generated. This light intensity distribution pattern is detected by the sensor. The light intensity distribution pattern depends on the particle size.

2 It changes.

 Since the actual measurement is a particle group, a plurality of particles of different sizes are mixed, so the light intensity distribution pattern generated from the particle group is determined by the superposition of diffraction and scattered light from each particle. Become.

 When measured by the laser diffraction type particle size distribution measuring device using the laser diffraction method, the above-mentioned superimposed light intensity distribution pattern can be detected. It is possible to calculate what proportion of particles of such a size are contained. Then, the particle size distribution can be obtained from the calculation result.

 For example, a graph as shown in FIG. 1 can be obtained. The horizontal axis of the graph in FIG. 1 indicates the particle diameter (μ ιη) (expressed in logarithm), and the vertical axis indicates the relative particle amount (%). Here, for example, “in the particle size distribution when the graphite particles are measured by the laser diffraction method, among the graphite particles, the integrated value of the graphite particles having a particle size of 10 to 40 m” is as shown in FIG. In the area enclosed by the particle size distribution and the horizontal axis, the ratio of the area of the shaded portion (the portion corresponding to a particle diameter of 10 to 40 // m) is meant.

 As the graphite particles used in the present invention, any of artificial graphite or natural graphite can be used. Further, graphite particles in which these are mixed may be used.

 Epoxy resins, phenol resins, and various thermosetting resins obtained by modifying these resins can be used as the resin that binds between the graphite particles. These resins have a binder content of 10

~ 40 ° /. It is preferred to use

 After using the thermosetting resin as a binder, the above-described graphite particles are mixed with a resin serving as a binder, and then molded into a predetermined shape.

Three JP2003 / 011366

Heat treatment is performed at a temperature of 150 to 250 ° C to obtain a carbon brush.

 The carbon brush according to the present invention may include a solid lubricant such as molybdenum disulfide, tungsten disulfide, and boron nitride in addition to the filler described above. The same effect can be obtained by applying to not only the above-mentioned thermosetting type carbon brushes but also to various types of car pump brushes called kneading and firing with phenolic resin or pitch and metal graphite type. is there.

 Hereinafter, the present invention will be described specifically with reference to examples.

 (Example 1)

As a laser diffraction type particle size distribution measuring device, SALD-200OA manufactured by Shimadzu Corporation was used. The same applies to the following examples and comparative examples.

 In the particle size distribution when the graphite particles serving as the filter were measured by the laser diffraction method, the integrated value of the graphite particles having a particle size of 5 / m or less (the particle size distribution and the horizontal axis in FIG. Of the enclosed area, the shaded area on the left (the horizontal axis is

The ratio of the area of 5 mu m or less parts)) was adjusted to so that Do 1 0% of the graphite particles FILLER one (average particle diameter of 6 2 m), the mode diameter of 5 7 _mu m in standard deviation 25% by weight of 0.25 artificial graphite powder and 25% by weight of epoxy resin as a binder were mixed and kneaded. The kneaded material was pulverized so that the content of 63 or less was about 50%, and then molded at 100 MPa to obtain a single pump brush.

 (Example 2)

 In the particle size distribution when the graphite particles serving as fillers were measured by the laser diffraction method, the integrated value of graphite particles having a particle size of 5 μm or less was 5%, and the particle size was 1% of the graphite particles. 0 Integrated value of graphite particles of 0 μm or more

 (In the area enclosed by the particle size distribution and the horizontal axis in Fig. 2,

Four 3 011366

The ratio of the area of the line part (the part of the horizontal axis is 100 μm or more) is 10. /. 25% by weight of an epoxy resin as a binder was mixed and kneaded with 75% by weight of artificial graphite powder adjusted to become a black sharp particle filler. This kneaded material was pulverized so that the content of 63 kππ or less was about 50%, and then molded with 100 MPa to obtain a carbon brush.

 (Example 3)

In the particle size distribution when the graphite particles serving as fillers were measured by a laser diffraction method, the integrated value of graphite particles having a particle diameter of 5 nm or less was 3%, and the particle diameter of graphite particles was 10%. The artificial value is adjusted so that the integrated value of graphite particles of 0 μm or more is 4%, and the integrated value of graphite particles with a particle diameter of 10 to 40 μm is 65% among graphite particles. 75% by weight of graphite powder and 25% by weight of epoxy resin as a binder were mixed and kneaded. The kneaded product 6 3 μ ΐη powder after grinding as following can be about ^50%, to obtain a carbon brush molded in 1 0 OMP a.

 (Comparative Example 1)

In the particle size distribution when the graphite particles serving as fillers were measured by the laser diffraction method, among the graphite particles, the cumulative value of graphite particles having a particle diameter of 5 μm or less was a black bell particle filter with an integrated value of 20%. adjusted to and kneaded by blending an epoxy resin 2 5 wt _^0/0 as a binder. The kneaded material was pulverized so that the content of 63 kππ or less was about 50%, and then molded at 100 MPa to obtain a carbon brush.

 (Comparative Example 2)

 In the particle size distribution when the graphite particles serving as fillers were measured by the laser diffraction method, the integrated value of graphite particles having a particle diameter of 5 μm or less was 30% and the particle diameter was 100 μm. The average value of graphite particles of m or more is adjusted to be a graphite particle filter of 10%.

Five Twenty-five percent by weight of the resin was mixed and kneaded. This kneaded material was pulverized so that a particle having a diameter of 63 μm or less became about 50%, and then molded at 100 MPa to obtain a carbon brush.

 (Comparative Example 3)

 In the particle size distribution when the graphite particles serving as the filler were measured by the laser diffraction method, the cumulative diameter of graphite tin particles having a particle diameter of 5 μm or less was 40% and the particle diameter was 1%. The integrated value of graphite particles of 0 μm or more is 15. Adjust so that the cumulative value of graphite particles with a particle diameter of 10 to 40 m becomes the same as the graphite particle filler of 55%, and mix and knead 20% by weight of general-purpose raw epoxy resin as a binder. did. The kneaded material was pulverized so that those having a particle size of 63 μΐη or less became about 50%, and then molded with 10 O M Pa to obtain a carbon brush.

 Each of the above car pump brushes was incorporated into a motor for a vacuum cleaner, and the service life was investigated. Fig. 3 summarizes the characteristics of each car pump brush.

Third As can be seen, the particle size distribution as measured graphite particles as a filler by a laser diffraction method, the accumulated value of the particle diameter of 5 mu _m or less black tin particles of graphite particles 1 0% It can be seen that the life of the carbon brush of Example 1 controlled to be the same as the graphite particle filter of Example 1 is 1.5 times longer than that of the uncontrolled carbon brush according to Comparative Example 1.

In addition, in the particle size distribution when graphite particles serving as fillers were measured by a laser diffraction method, the integrated value of graphite particles having a particle size of 5 μm or less was 5%, and the particle size of graphite particles was 5%. The car pump brush of Example 2 in which the integrated value of graphite particles of 100 μm or more is controlled to be a graphite bell particle filler of 10 ° / _{0 is} the same as the uncontrolled carbon brush according to Comparative Example 2.

6 In comparison, it is found that the service life is extended about twice.

 In addition, in the particle size distribution when the graphite particles serving as the filler were measured by the laser diffraction method, the integrated value of the graphite particles having a particle size of 5 nm or less among the graphite particles was 3%, and the particle size of the graphite particles was 3%. Control so that the integrated value of graphite particles with a particle size of 100 μm or more is 4%, and the integrated value of graphite particles with a particle size of 100 to 40 μm is 65% among graphite particles. It can be seen that the service life of the carbon brush of Example 3 is about three times longer than that of the uncontrolled carbon brush according to Comparative Example 3.

 Therefore, it was confirmed that the present invention can provide a carbon brush having a significantly longer life than conventional products.

 The present invention can be changed in design without departing from the scope of the claims, and is not limited to the above embodiments and examples. Industrial applicability

 It is possible to make the filler structure of the graphite particle filler uniform, and to provide a carbon brush having a long life using the graphite particle filler.

7

Claims

 The scope of the claims  1 · A carbon brush whose particle size distribution is 10% or less of graphite particles with a particle size of 5 m or less in the particle size distribution when black sharp particles serving as fillers are measured by a laser diffraction method.  2. The car pump brush according to claim 1, wherein an integrated value of graphite particles having a particle diameter of 100 µm or more among the graphite particles is 10% or less.  3. The carbon brush according to claim 2, wherein an integrated value of graphite particles having a particle diameter of 10 to 40 m among the graphite particles is 60% or more.  4. The car pump brush according to claim 3, wherein an integrated value of graphite particles having a particle diameter of 12 to 20 m among the graphite particles is 40% or more.  5. The carbon brush according to any one of claims 1 to 4, wherein the carbon brush is selected from a resin-cured carbon brush, a carbonized carbon brush, and a carbon brush in which metal and graphite are combined.