JPS62126577A - Signal transmission brush - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the provision of a brush suitable for signal transmission.

It goes without saying that contact wires such as insulated trolleys are widely used for power supply to mobile devices, but recently there has been an increase in the number of cases in which this type of wire is employed for signal transmission.

As is well known, this type of contact wire supplies power to a mobile device by sliding the wire while pressing a conductor on an exposed conductor surface that is continuous in the length direction.

For such brushes, a metal graphite material called a carbon brush is used, and in order to minimize wear, solid lubricants (molybdenum disulfide, tungsten disulfide) are added to improve lubricity. things were being used.

However, the addition of this solid lubricant increases the contact resistance of the brush to the sliding conductor, which is not a big problem if the brush is used for power applications with large voltages and currents, but it becomes a problem when used for signals with small voltages and currents. Solid lubricants were harmful to proper signal transmission.

In view of this problem, as a brush for signal transmission,
Metal-graphite materials that do not contain solid lubricants have been used.

[Problem that the invention seeks to solve]

The signal transmission that has been targeted in the past is a random method that handles TL magnetic signals, and the equipment operates infrequently and only operates and sends signals when necessary, so it is prone to wear and tear. Since it requires less lubricant, we were able to use the metal graphite material without the solid lubricant mentioned above.

However, for recent mobile devices, many remote monitoring and control devices using semiconductors are being adopted, and most of them use a cyclic transmission method, which constantly scans monitoring items and sends the information. It has become

In the case of the cyclic signal transmission method, the signal transmitting/receiving section is made of a semiconductor and has no contact points, and the signal is transmitted sequentially and repeatedly at high speed.

When used more frequently, metal graphite materials without lubricants generate a large amount of abrasion powder due to the increased amount of sliding of the brush against the sliding conductor, and most of the abrasion powder is metal. It is an oxide, and when it adheres and accumulates on the sliding surface and gets caught in the sliding part of the brush, it increases the contact resistance, causing a voltage drop or causing an instantaneous M line.

The voltage drop caused by such contact resistance is small and does not pose much of a problem when both voltage and current are used for large power applications, but when used for signals that handle weak currents at low voltages of the order of 12V and several mA, it is important to avoid noise. This may cause malfunction of the equipment, and this is further amplified by the momentary disconnection.

When supplying electric power, the arc generated by high voltage and current can destroy such metal oxides, but low voltage and current can destroy such metal oxides.
In the case of current signal transmission, such destruction of the metal oxide does not occur, and if left as is, abrasion particles harmful to transmission will still remain, making it impossible to perform correct signal transmission.

In conventional current collection brushes, the brush itself is coated with chromium, iron, and
There are other brushes that have self-polishing properties by adding hard metal substances, but these hard metal substances damage the sliding surface, which actually increases the contact resistance of the brush to the sliding conductor. It was difficult to adopt it for signal transmission.

In view of the current situation, the present invention is designed to reduce the contact resistance by suppressing the use of harmful lubricants at low voltages and currents, and to easily remove wear particles that inevitably occur during the sliding process, thereby making it possible to signal The aim is to provide a brush that is optimal for transmission.

[Means for solving problems]

As a result of intensive research by the inventors on a signal transmission brush that solves this problem and achieves the purpose, the inventors have developed a brush that is based on a metal-graphite material that does not contain a solid lubricant and has silicon carbide powder added to it in an amount of 1% by weight or less. was found to be effective.

Metallic graphite materials contain copper, tin, lead, and carbon.
Copper ensures conductivity, tin adjusts hardening, and lead and carbon provide the minimum necessary lubricity.

A preferred composition is as shown below.

Coppernia: 9-89% by weight Tin: 7-13% by weight Lead: 2-5% by weight Carbon: 1-7% by weight The added silicon carbide powder acts as an abrasive, and the preferred amount added is 0.1%. ~11i amount%.

In other words, if it is less than 0.1% by weight, the polishing effect will not be noticeable, and if it exceeds 1% by weight, the brush itself will become very hard, making it difficult to process (even a slight impact may damage it, and the brush This is because there is a possibility that the tap hole may collapse if a 7-beam process is added to the lead wire for attaching the lead wire.

[Effect]

After molding, the silicon carbide powder becomes dry and mixes appropriately with the abrasion powder during the abrasion process that occurs during sliding on the sliding conductor. This improves the peelability of the abrasion powder from the sliding conductor and prevents the brush from running. This makes it easier to scatter from the sliding surface.

In addition, silicon carbide powder has a low-grain function as a grinding wheel, so
Polishing not only helps the oxide adhering to the sliding surface to peel off and fall off, but also maintains a fresh conductive surface.

Furthermore, since silicon carbide is a powder, there is almost no roughening of the sliding surface.

〔Example〕

A preferred embodiment is shown below.

Copper, tin, lead, carbon, and silicon carbide were mixed according to the formulation shown below, and the resulting mixed powder was pressed to produce a brush in a predetermined shape.

1: 84 weight 11% Tin = 1O weight% Lead: 3 weight% Carbon: 2.5 weight% Silicon carbide 20.5 weight% In order to confirm the performance of the brush with the above composition, it was tested under the following conditions. A sliding test was conducted, but no noise was observed in the transmitted signal.

Sliding conductor: Trolley wire with sliding surface made of electrolytic copper Signal voltage:
12v Signal current: 10mA Sliding speed: 60m/min sliding path! : 15,000 reciprocations over a period of 50 m Under the above test conditions, solid lubricants (molybdenum disulfide, molybdenum disulfide,
Tests were also conducted on brushes made of metal-graphite material containing tungsten disulfide (Tungsten disulfide) and metal-graphite brushes without the solid lubricant, but the other brush also generated a lot of noise in the transmitted signal. It was done.

〔Effect of the invention〕

As is clear from the above explanation, the signal transmission brush of the present invention has low contact resistance and efficiently removes abrasion powder that inevitably occurs due to sliding.
Even though it is a current, it can completely eliminate noise generation, and since only a small amount of silicon carbide is added, it can be manufactured in the same way as conventional brushes.
The practical benefits are truly great, such as contributing to mass production and being economical.

Claims (1)

[Claims] 1. A signal transmission brush characterized by being made of metal graphite containing no solid lubricant and containing 1% by weight or less of silicon carbide powder.