JPS5942429B2 - Electric brush for electrical machinery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in electric brushes for electrical machines (hereinafter referred to as electric brushes).

In general, electric brushes for electrical machines are porous and are thought to retain rectifying ability because they absorb impact vibrations transmitted from the mating sliding body and improve sliding contact.

However, when the impact vibration of the opposing vibrating body becomes intense, normal sliding contact cannot be maintained. Therefore, making the electric brush more porous essentially weakens the bonds between the particles, and when shock vibration stress is applied to the sliding contact end of the electric brush, the interparticle bonding force of the electric brush decreases and the particles It becomes easy to fall off, and the wear of the electric brush increases. In order to improve this, in the case of electric brushes made of electrographite or the like, a method is used in which the particles are impregnated with phenol resin, epoxy resin, etc. to strengthen the bonds between the particles before forming the electric brush into the shape of the electric brush. In this impregnation process, in order to prevent the resin from partially flowing out from the pores of the electric brush material before curing is completed, for example, piperidine, phthalic acid, etc.
A method is used in which a curing agent such as an amine type curing agent is mixed in advance with the resin liquid. However, in electric brush materials treated with this method, uneven distribution of resin may be unavoidable.
In addition, the mechanical strength of this electric brush material is on average higher than before impregnation treatment, and its wear resistance is also improved, but microscopically, the distribution differs depending on the amount of resin impregnated and the degree of hardening, so when sliding When an impact is received from the sliding member, the electric brush may jump due to lack of vibration absorption ability, and the mechanical stress applied to areas with a large amount of impregnation or hardening is concentrated on areas with a small amount of impregnation or hardening. The agglomerated particles may fall off and cause sinkholes on the sliding contact surface, or the fallen particles may interpose on the sliding contact surface between the electric brush and the mating sliding body and cause sliding failure, reducing the rectifying ability. There were problems such as a decline in The present invention aims to solve the above-mentioned problems and provide an electric brush with improved wear resistance and excellent rectification ability.

As a result of our research, the present inventors found that, instead of impregnating the Eyeichi resin as in the past, we adopted a solution containing a bisphenol-based epoxy compound, a cycloaliphatic epoxy compound, and an organometallic compound. It has been found that an electric brush that achieves the above object can be obtained.

The present invention relates to an electric brush for electrical machinery, which is formed by impregnating and thermally curing a solution containing a bisphenol-based epoxy compound, a cycloaliphatic epoxy compound, and an organometallic compound into the pores.

The electric brush of the present invention is made of a bisphenol-based epoxy compound (hereinafter referred to as resin A), a cycloaliphatic epoxy compound (
It is obtained by impregnating an electric brush material with an impregnating liquid prepared by diluting an organometallic compound (hereinafter referred to as additive C) with a solvent such as acetone, and processing it after thermosetting.

The desirable blending ratio of resin A, resin B, and additive C is
35-50 parts by weight, resin B 35-50 parts by weight, additive C
There is no force ζ limit, which is 5 to 20 parts by weight. Further, the additive C is, for example, butyl lithium, ethyl lead, methyl sodium, or the like. The impregnation rate of the resin to the electric brush material (weight increase rate of the electric brush material) is 1 to 5% by weight, but preferably 3+
The impregnation rate is 0.5% by weight, and the concentration of the impregnating solution is adjusted to match this impregnation rate. However, the impregnation rate for electric brush materials with few pores may be 1 to 2% by weight in some cases. Next, an example will be described.

Table 1 shows the composition of the impregnated product and the impregnation rate when it is cured at a maximum temperature of 200°C. In Table 1, 1 is non-impregnated electric brush material, 2
-6 are impregnated electric brush materials of comparative examples, and 7 and 8 are impregnated electric brush materials of electric brushes according to the present invention. An electric brush material having the physical properties shown in Table 2 1 was degassed under reduced pressure, and an impregnating solution prepared by diluting the mixture of the composition shown in Table 1 with acetone to a specified concentration was injected and held for 1 hour, and then taken out into the atmosphere for 24 hours. Air dry.

After this, the temperature was increased to 120°C using an electric dryer at a rate of 10°C per hour.
After holding at this temperature for 6 hours, the temperature was raised to 20°C at a rate of 5°C per hour and held at this temperature for 2 hours to cure. These special characteristics are as shown in Table 2, and the impregnated electric brush materials 7 and 8 of Examples, as well as the impregnated electric brush materials of Comparative Examples, have higher bending strength and better strength than non-impregnated electric brush materials. Both Young and Tsu are big. The electric brush materials shown in Table 2 were processed into electric brushes, and a wear test was conducted using a simulated commutator with a circumferential speed of 35 m/s.

In the simulated commutator, eight uneven portions are artificially provided in advance on one peripheral surface of the sliding body, so that the electric brush collides with the uneven portions during sliding. Table 3 shows the wear amount (Mm) of electric brushes converted to driving distance per 10,000 km, and as is clear from Table 3, electric brushes 7 and 8 of the present invention
The wear is small ~ Also, as a rectification test, a normal commutator surface (commutator unevenness of 5 μm)
The results of measuring the width of the non-spark rectifying zone of the test electric brush using a 100KW shunt-wound DC motor with
It is shown in Fig. 2 and Fig. 2.

For an electric machine that uses an electric brush, the horizontal axis shows the load current, that is, the total amount of current flowing through the electric brush, and the vertical axis shows the amount added or decreased to the fixed point winding excitation current of the rectifying pole (commuting pole) of the electric machine. The no-spark zone of an electric machine is expressed by taking the current, that is, the interpolation current, and expresses the mutual relationship (JEC-54). It is said that the electric brush has a great rectifying ability. As is clear from the figure,
It can be seen that the electric brushes 7 and 8 of the present invention have a wide non-spark rectifying zone and good rectifying performance. This is considered to be due to the synergistic effect of Resin A and Resin B and the appropriate effect of fixing the inner walls of the pores due to Additive C.

In addition, even in a wear durability test using a simulated commutator with artificially uneven surfaces, copper dragging,
No phenomena such as commutator blackening or ghost marks were observed. This is thought to be because the electric brush sufficiently follows the irregularities of the commutator. This is considered to be because the impregnated cured product of the electric brush according to the present invention has the same viscoelastic effect as the electric brush material. Of course, if the irregularities of the commutator are made larger than 60 to 80 μm, smooth sliding with good followability as described above cannot be expected. It does not develop into significant sparks (sparks with enough energy to melt copper) over time due to burnout, and maintains a uniform particle surface with a slightly dark gloss and a constant spark. It turned out that. This is considered to be because the impregnated cured product of the electric brush of the present invention is more stable even when exposed to high temperatures than the impregnated cured product of the conventional electric brush. The electric brush for electrical machines of the present invention can be obtained by impregnating an electric brush material, which is porous in nature, with an appropriate amount of a solution containing a bisphenol epoxy compound, a cycloaliphatic epoxy compound, and an organometallic compound, and then thermally curing the electric brush material. According to
It has appropriate viscoelasticity and lubricity, does not generate harmful substances even under high temperatures that generate some sparks, has excellent rectification performance, and has low abrasion loss of the electric brush itself, so it is suitable for rotating electric machines. It can extend the service life and improve maintenance efficiency.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams showing the spark-free zones of electric brushes of Examples and Comparative Examples obtained by processing the electric brush materials shown in Table 2. Explanation of symbols 1... Electric brush without impregnation, 2... Electric brush impregnated with bisphenol epoxy compound, 3... Impregnated with a mixture of 90 parts by weight of bisphenol epoxy compound and 10 parts by weight of organometallic compound. Electric brush, 4... Electric brush impregnated with a cycloaliphatic epoxy compound, 5... Mixture of 90 parts by weight of a cycloaliphatic epoxy compound and an organometallic compound 10
Electric brush impregnated with 6 parts by weight... 5 parts each of bisphenol epoxy compound and cycloaliphatic epoxy compound
An electric brush impregnated with a mixture of 0 parts by weight of a mixture, 7... an electric brush impregnated with a mixture of 50 parts by weight of a bisphenol epoxy compound, 45 parts by weight of a cycloaliphatic epoxy compound, and 5 parts by weight of an organometallic compound, 8... a bis An electric brush impregnated with a mixture of 45 parts by weight each of a phenolic epoxy compound and a cycloaliphatic epoxy compound and 10 parts by weight of an organometallic compound.

Claims (1)

[Claims] 1. An electric brush for electrical machinery, which is obtained by impregnating the pores with a solution containing a bisphenol-based epoxy compound, a cycloaliphatic epoxy compound, and an organometallic compound and then curing the resultant mixture under heat.