JP3328865B2 - Carbon brush and impregnation method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for impregnating a carbon brush impregnated with an impregnating component, in particular a carbon brush or a carbon bar made of the carbon brush for a tool subjected to high stress.

[0002]

BACKGROUND OF THE INVENTION U.S. Pat. No. 949,988 discloses an impregnated carbon brush for electrical equipment, the carbon brush comprising a lubricant grease,
Has impregnating components including wax or oil. At room temperature, the impregnating agent is fluid or solid and is brought to a temperature equal to or above the melting point of the lubricant in the impregnation bath in which the carbon brush is impregnated. If vaseline is used as the impregnation component, for example, the impregnation temperature is adjusted to about 100 ° C. After the impregnation step, the carbon brush is then treated at a temperature at least as high as the maximum operating temperature.

[0003] German Patent Publication No. 1200935 and German Patent Publication No. 1171982 show that carbon brushes can be impregnated with esters. It is also possible to use, on the one hand, mixtures of polyoxide alkenediols and their esters, on the other hand, mixtures of aliphatic carboxylic acids having 8 to 25 carbon atoms and salts of these acids as impregnating agents. (U.S. Pat. No. 2,425,046).

[0004] German Patent 2,609,834 discloses impregnated carbon brushes containing unmelted grease, wax or oil as impregnating agent, which grease, wax or oil is made of montmorillonite whose surface is coated with long-chain hydrocarbons. It is intimately mixed with the flake gelling agent and is thus converted into a non-melting, non-flowing, harder and corrosion resistant state. The impregnation is performed by a vacuum pressure method.

[0005] The impregnated carbon brushes disclosed in DE 2609834 are well documented by their use, but have the advantages of good commutation, lower spark disturbance, longer life and convenience at higher voltages. is there. However,
Where brush wear, collector wear, collector temperature during operation or equipment life is desired, it is desirable to have additional advantages, especially when used in equipment with asbestos-free temperature-sensitive commutators. there were.

Accordingly, it is an object of the present invention to improve the conventional method of impregnating a carbon brush of this kind, to further improve the mechanical properties of the carbon brush and to be able to use it without problems especially for asbestos-free commutators. is there. Still another object of the present invention is to suppress spark failure and further improve resistance to temperature. Further, in the impregnation step, no solvent is used, and the impregnating agent should be safe for the environment.

[0007]

According to the present invention, the above objects can be attained by impregnating a carbon brush with a mixture of an ester oil and a synthetic hydrocarbon oil.

[0008] The ester oil is preferably a synthetic ester oil such as a carboxylic acid or dicarboxylic acid ester.

Particularly, the carbon brush is about 14 mm at 100 ° C.
^It has a kinematic viscosity of ² / S and about 63 mm ² / S at 40 ° C.
Impregnated with an ester oil having a kinematic viscosity of The ester oil should also have a density at 20 ° C. of about 0.92 g / cm ³ .

[0010] If a carbon brush impregnated according to the invention is used, the commutator temperature is surprisingly greatly reduced, ensuring a long service life and a clear reduction in commutator corrosion. Therefore, this carbon brush is particularly suitably used for asbestos-free equipment.

Particularly, when the amount of the impregnating agent of the carbon brush is about 0.5 to 15% by weight, preferably about 5% by weight,
A reduction in brush and commutator wear and a reduction in collector temperature have been achieved.

In the method, the above object is achieved by immersing a carbon brush in a mixture of an ester oil and a synthetic hydrocarbon oil.

Surprisingly, the impregnation with the impregnating agent according to the invention does not require a vacuum pressure method. The carbon brush or its carbon bar need only be immersed in the mixture of ester oil and synthetic hydrocarbon oil for a certain period of time. This immersion time is preferably 0.5 to 5 hours, particularly preferably 1.5 to 2.5 hours. Thereafter, the excess mixture is removed from the carbon brush or carbon bar and then dried, preferably by rotating means, at a temperature between 50C and 90C. In particular, drying at about 80 ° C. for about 5 to 20 minutes, preferably about 10 minutes is good. This renders the carbon brush ready for use, and the carbon bar is machined and finished to the desired shape as a carbon brush.

[0014] Further features and advantages of the invention will be apparent from the claims, as well as from the embodiments of the invention illustrated below.

[0015]

EXAMPLE A carbon brush is immersed in undiluted synthetic ester oil at room temperature for about 2 hours and then removed to remove the ester oil. And about 80 carbon brushes
Spin dry for 10 minutes at a temperature of ° C. This makes the carbon brush ready for use. Thereafter, no rinsing was performed.

Tests of the finished carbon brush showed that the weight percent of impregnating agent was about 5%.

Next, the operating time of the carbon brush,
It was installed on a portable electric saw to determine brush wear, collector wear, resulting service life and collector temperature. The test results were compared to carbon brushes impregnated with a known impregnant. Then, the results shown in Table 1 below were obtained.

[Table 1]

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Günther Schard 35398 Giessen-Klein-Linden, Bulgameister-Jung-Bake 6 Examiner Ichiro Kotani (56) References JP-A-3-49546 ( JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01R 39/20 H01R 43/12 H02K 13/00

Claims (3)

(57) [Claims] 1. A method of impregnating a carbon brush or carbon bar, wherein the carbon brush or carbon bar is immersed in a mixture of ester oil and synthetic hydrocarbon oil for a time "t" and the time "t" Is 0.5h (hour) <t <5h
(Time), then the excess ester oil is removed, and finally the carbon brush or bar is dried at a temperature "T", where the temperature "T" is 50 ° C <T <90 ° C
A method characterized by the following relationship. 2. The method according to claim 1, wherein the carbon brush or bar is operated for a time "t"
Method according to claim 1, characterized in that the drying is carried out during the period, said time "t" being 15 minutes <t <20 minutes, preferably t = 10 minutes. 3. The method of claim 1, wherein the carbon brush or bar is rotated during drying.