JP2002017073A - Noble metal clad brush wire and slip ring assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize cracking on a noble metal surface as compared with plated material while avoiding the high cost of a gold alloy monofilament wire, and use other noble metals in place of gold. SOLUTION: This slip ring and brush assembly utilizes gold cladding brush wires in sliding or rotating contact with a gold covered slip ring. The gold cladding has the metallurgical bonding to the underlying wire.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates generally to slip rings and wire brush assemblies, and more particularly, to the use of a noble metal material to form the surface layer of a wire brush.

[0002]

BACKGROUND OF THE INVENTION Slip ring assemblies are well known in the art and generally include a rotating conductor ring that contacts a non-rotating brush mounted in a suitable brush holder. The brush is often a one-piece wire member, the wire member comprising a gold alloy brush wire or a gold plated wire extending opposite the gold plated ring. Gold or other noble metals are particularly preferred. This is because, as is known for a considerable period of time, in order to achieve the performance of changing the contact resistance over a long period of time (years) to a low milliohm level, noble metals or noble metal alloys rather than base metals. Must be used in the electrical contact area.

[0003] Gold alloy brush wires can be expected to operate over a long period of time with minimal changes in contact resistance. However, gold alloy wires are relatively expensive. This is because the gold content is high.

[0004] Gold-plated wires are also known and tend to be less expensive than gold alloy wires. This is because less expensive base metals are covered by gold plating. However, the gold plating is liable to break, especially when the gold-plated brush wire is bent to a specific radius of curvature for a particular type of application. In addition, from a manufacturing perspective, the production of plated wires requires greater capital investment in terms of the need for plating baths and equipment, as well as environmental waste issues and additional associated costs. Occurs.

[0005]

DISCLOSURE OF THE INVENTION Accordingly, it is an object of the present invention to improve the structural integrity of a brush wire with a noble metal coating.

[0006] Another object is to improve the wear characteristics of precious metal coated brush wires.

Yet another object is to improve the structural integrity and wear characteristics of precious metal coated brush wires compared to plated wires, while reducing costs compared to precious metal alloy wires. is there.

[0008] The present invention is directed to a slip ring and brush assembly, including a slip ring in sliding contact with a brush wire. In a broad sense, the invention relates to a brush wire, wherein the brush wire forms a first material forming at least a portion of a wire core and a second material forming an outer layer metallurgically bonded to the first material. And the improvement of the point including the material.

In a preferred embodiment, the present invention relates to a slip ring and brush assembly for transferring electrical energy between a conductor and a shaft. One of the conductor and the shaft is stationary, while the other is rotating. The assembly includes a noble metal coated slip ring surface formed on a shaft and at least one brush wire in contact with the noble metal coated slip ring surface and connected to the conductor. According to the present invention, a brush wire comprises a conductive core, a metal barrier layer optionally covering the core, and a noble metal surface layer metallurgically bonded to one of the barrier layer and the core. .

At the atomic level, the noble metal surface layer is metallurgically bonded to the underlying core, either directly or through an intermediate metallurgically bonded barrier layer. Providing a tighter bond advantageously results in better brush formation, thereby minimizing cracking and delamination of the noble metal surface compared to prior art plating techniques. Also, brush wires formed with metallurgically bonded precious metal surfaces tend to be less expensive than gold or precious metal alloy wires by reducing their gold or precious metal content. A similar noble metal contact is maintained at the ring / brush interface, resulting in low noise and wear.

The brush wire according to the present invention may have a metal barrier layer for preventing the diffusion between the conductive core and the noble metal surface layer depending on the selection of a material in which diffusion between a plurality of materials is problematic. Use as needed. If a noble metal barrier layer is utilized, the barrier layer is preferably metallurgically bonded to the conductive core, and the noble metal surface layer is now metallurgically bonded to the barrier layer. Have been.

In one preferred embodiment according to the invention, the brush wire comprises a copper center core, preferably beryllium copper, and comprises a nickel clad cladding barrier, the gold cladding on the outer surface of the nickel barrier. Is accompanied.

Still other objects and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description, and in the following detailed description, only preferred embodiments of the present invention are described. Is illustrated and described merely by describing the best mode contemplated for practicing the invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modification in various obvious respects, all without departing from the invention. can do. Accordingly, the drawings and description are to be regarded in the nature as illustrative and not restrictive.

FIG. 1 is an illustrative drawing of a slip ring and brush assembly, generally designated by the reference numeral 10, wherein a series of brush wires 12 are mounted on a rotating slip ring. Sliding contact is made with the slip ring surface 14 formed on the assembly 15.
The surfaces of brush wire 12 and slip ring surface 14 are preferably coated with gold, as is well known, to achieve good wear properties, low electrical resistance and increased current density. However, in accordance with the specific features described above, each brush wire 12 is provided with a surface layer 16, which in a preferred embodiment is either directly to the lower conductive core 16b or to the diffusion layer 16c ( FIG.
) Is in the form of a gold cladding layer 16a which is metallurgically bonded via a diffusion layer 16c, which is now metallurgically bonded to the core. In this way, while the advantage of low contact resistance of gold on gold is obtained, the problem of high degree of fatigue and failure associated with gold plating or the high cost of gold alloy due to the high gold content of gold alloy is reduced. Can be avoided.

The assembly 10 represents a broad class of brush wire and slip ring assemblies in which a rotating conductive slip ring assembly 15 is non-rotating mounted in a suitable brush holder. The contact with the brush 12 provides a flow path for electric power and signals. 1, the assembly 10 includes a cylindrical housing 20 in which a pair of bearings 2 are mounted.
Two and 24 are located at opposite ends of the slip ring assembly 15 and rotatably hold one end of a rotating shaft 28. A series of brush wires 12 are axially separated from each other and are in contact with annular grooves 30 formed along the length of the slip ring assembly 15.

More specifically, upper and lower sets of the axial sets 12a and 12b of the same brush wires 12 which are separated from each other in the axial direction are placed on the upper and lower brush blocks 32 and 34, respectively. Block 32
And 34 provide proper positioning of the wire in sliding or rotational contact with groove 30 of the slip ring assembly. As best shown in FIG. 1, each brush block assembly 32 and 34 extends the entire length of the slip ring assembly 15 and has opposing ends, where the opposing ends are Bearings 22 and 24
, Respectively, to properly position these bearings within the assembly 10. These brush blocks 32 and 34 are also used to position and position the lead wire 36 and provide a lead outlet as known in the art. The lead wires 36 are made of the brush block assembly 3 by using a potting material 38 disposed between the outer surface of each brush block and the inner inner wall of the housing 20.
2, 34 are held in a position associated therewith. Housing 20
The retainer ring 40, located at the concave base end of the shaft, axially secures the brush block assemblies 32, 34 to the rotating shaft 28, while the end cap 42 is attached to the distal end of the assembly 10. And a lead wire 36 extends through the end cap.

The configuration of the assembly 10 described above is normal except for the configuration of the brush wire 12. As best shown in FIG. 2, each brush wire 12 has a surface layer 16 in a preferred embodiment, and
6 is a cladding layer 16 that is metallurgically bonded to a lower conductive core 16b, preferably via a diffusion layer 16c.
a. This cladding layer 16a is preferably
It is made of precious metals such as gold. This outer layer 16a
Are metallurgically bonded to the lower core 16b or diffusion layer 16c, thereby achieving much better adhesion than previously achieved with gold or noble metal plating, which is due to the plating technique. This is because the poor adhesion between the plated layer and the substrate, as is inherent in the prior art, tends to wear the plated material earlier. The disadvantages inherent in such plating methods are particularly pronounced and disadvantageous in products that rely on one or more brush wires in sliding or rolling contact with an engaging slip ring assembly.

The brush wire 12 constructed in accordance with the unique features of the present invention has similar performance (ie, reduced wear rate and longevity) to that obtained with a brush wire of high gold content and therefore of a more expensive gold alloy. ), And without the attendant costs. Also,
The precious metal clad brush wire 12 of the present invention provides better conductivity than similarly sized gold alloy wire by bonding to a center core material 16b that is selected to have better conductivity than pure gold alloy. Can bring sex. Since the clad layer 16a can be bonded to the center core 16b made of a different material, the obtained brush wire 12 can be used in accordance with the selection of the center core material.
It can have better mechanical properties than gold alloy wire.

Also, the feature of using a noble metal clad wire results in better bond adhesion in metallurgical bonding than plating, resulting in better formability than plated wire. It is.
Such an improvement in formability has been proven by a lower incidence of cracking and peeling of the surface layer 16a, which is particularly useful when the brush wire is bent over a tight radius. The noble metal clad wire of the present invention is particularly useful when used in a horseshoe-shaped brush wire, for example of the type illustrated in FIG. 3, as used in the preferred embodiment assembly 10.

The present invention is not limited to the use of gold, but is intended to include other precious metals. Also, for brush wires for sliding or rolling contact, where the surface material forming the outer layer is metallurgically bonded to the core material, with or without an intermediate cladding layer. Thus, the present invention is applicable, thereby realizing the advantages of metallurgical bonding described above that would not be realized by applying this surface material using plating techniques.

The present invention is applicable to the use of both monofilament and multifilament materials forming individual brush wires and brush wire assemblies.

In a preferred embodiment, each wire 1
2 is formed with a gold outer layer 16a metallurgically bonded to a diffusion layer 16c (e.g., nickel), which in turn is metallurgically bonded to a core 16b (e.g., beryllium copper). Are logically linked. Under certain circumstances, depending on the choice of material forming the outer cladding layer 16a and core 16b, the diffusion layer 16c may not be needed, in which case the outer layer is metallurgically bonded to the core.

FIG. 4 is a side elevational view showing details of a multifilament brush assembly 100 that may include a plurality of filaments 102, wherein filaments 102 comprise 1-2 filaments.
5 mil (2.54 × 10 ⁻³ cm to 6
3.5 × 10 ⁻³ cm) and are held in one piece by the collar 104. The collar 104 may include a wire insulation end,
Alternatively, the fibers 102 may be placed in a selectively shaped bundle.
May be a separate tubular member specifically designed to hold As shown, the fiber 102 extends a sufficient distance from the collar 104 so that it is well known (eg, US Pat. No. 4,398,11).
No. 3), making it possible to bring the collar into tangential contact with the slip ring surface.

In accordance with the present invention, each fiber 102 is constructed in a manner similar to that described above that is in contact with the brush wire 12. That is, each fiber 102 is preferably in the form of a cladding layer that is metallurgically bonded to the underlying conductive core, preferably via a diffusion layer.
This cladding layer is preferably made of a noble metal such as gold. The feature of metallurgical bonding of the outer layer to either the lower core or the diffusion layer (which is now metallurgically bonded to the core), as in the case of brush wire 12, is described above. Thus, much better adhesion is obtained than previously achieved by gold or precious metal plating.

It will be readily apparent to one skilled in the art that the present invention fulfills all of the objects set forth above. After reading the foregoing specification, one skilled in the art will be able to make various modifications, equivalent replacements and various other embodiments of the invention as broadly disclosed herein. Accordingly, the protection provided for the present invention is:
It is intended to be limited only by the limitations contained in the appended claims and equivalents thereof.

[Brief description of the drawings]

FIG. 1 is a longitudinal cross-sectional view showing details of an exemplary brush assembly utilizing a novel brush wire constructed in accordance with the present invention.

FIG. 2 is an exploded perspective view of one brush wire, taken along line 2-2 of FIG. 1;

FIG. 3 is a side view showing one brush wire.

FIG. 4 is a side view showing details of the multifilament assembly.

 ──────────────────────────────────────────────────の Continued on the front page (71) Applicant 501021232 21240 Burbank Boulevard Woodland Hills, California 91367-6675 United States of America (72) Inventor Barry K. Witherspoon United States 24060 Blacksburg, Virginia, College View Drive 514 F-term (reference) 5H613 AA01 AA03 BB05 BB17 BB19 BB24 BB26 BB33 GA04 GA09 GA10 GA12 GB01 GB05 GB08 GB09 GB13 GB14 QQ04 QQ05 SS05

Claims (14)

[Claims] 1. A slip ring and brush assembly for transferring electrical energy between a conductor and a shaft, wherein one of the conductor and the shaft is stationary, and wherein the conductor and the shaft are The other is a rotating structure, wherein the assembly comprises a noble metal-coated slip ring surface formed on the shaft, and at least one of the noble metal-coated slip ring surface, the at least one being in contact with the noble metal-coated slip ring surface and connected to the stationary conductor. A brush wire, wherein the at least one brush wire is metallurgically bonded to one of the conductive layer, an optional metal barrier layer covering the core, and the barrier layer and the core. A slip ring and brush assembly having a noble metal surface layer. 2. The slip ring and brush assembly according to claim 1, wherein said metal barrier layer is further formed of a material that prevents diffusion between said conductive core and said noble metal surface layer. 3. The slip ring and brush assembly according to claim 2, wherein said metal barrier layer is metallurgically bonded to said conductive core. 4. The slip ring and brush assembly according to claim 2, wherein said conductive core is copper, said barrier layer is nickel, and said noble metal surface layer is gold. 5. The slip ring and brush assembly according to claim 1, wherein said brush wire is smoothly curved along at least a portion of its entire length. 6. The slip ring and brush assembly according to claim 1, wherein said brush wire is drawn to a desired size. 7. The slip ring and brush assembly of claim 6, wherein said brush wire is formed without any heat treatment after drawing. 8. The slip ring and brush assembly according to claim 1, wherein said brush wire is a single monofilament wire. 9. The brush wire includes a bundle of a plurality of filaments, each filament being the conductive core, the optional metal barrier layer covering the core, and the barrier layer and the core. The slip ring and brush assembly according to claim 1, comprising the noble metal surface layer metallurgically bonded to one of the two. 10. The slip ring and brush assembly according to claim 1, wherein said slip ring surface is plated. 11. The slip ring surface is metallurgically bonded to the lower surface or plated.
The slip ring and brush assembly according to claim 1. 12. The conductive core is a beryllium copper center core, the barrier layer is a nickel clad barrier layer, and the noble metal surface layer is a gold clad layer.
The slip ring and brush assembly according to claim 1. Wherein said diameter of beryllium copper center core is about 0.018 cm (0.007 inches), about 0.191 × ^{10 -} 3 cm~0.381 × ^10
A 75 cm to 150 micro inch nickel clad barrier and about 0.254 × 10 ³ cm to 1.27 × 10 on the outer surface of the nickel barrier;
^{- 3} cm and a gold cladding (100 to 500 microinches), slip ring and brush assembly of claim 12, wherein. 14. A slip ring and brush assembly including a slip ring in sliding contact with a brush wire, wherein the brush wire includes a first material forming at least a portion of a core, and a first material forming at least a portion of the core. And a second material forming a metallurgically bonded outer layer.