1. Field of the Invention
The present disclosure relates to an insulated assembly of insulated electric conductors wherein each conductor is individually insulated in an anodized aluminum dielectric layer, bundled together in various configurations, and then the bundled configurations are insulated in an anodized aluminum dielectric layer.
2. Background Art
In co-pending patent application Ser. No. 11/627,486 filed on Jan. 26, 2007, a single stranded copper conductor with an anodized aluminum dielectric layer was disclosed. That application described an insulated electric conductor for carrying signals or current having a copper core of various geometries with a single thermally conductive dielectric layer of anodized aluminum (aluminum oxide). That application is incorporated herein by reference.
Conventional wire assemblies having polymeric insulation around copper wires can typically tolerate ohmic (or other) heating of up to approximately 250° C. Once a copper wire heats to temperatures beyond 250° C., the polymeric insulation can break down or melt, thus resulting in short circuits and related failures. Additionally, polymeric insulation is limited in its capacity to tolerate environmental hazards such as exposure to salt spray and other environmental conditions as are typically encountered by insulation employed in automotive applications.
While the single copper conductor described in U.S. patent application Ser. No. 11/627,486 would be capable of tolerating heating (ohmic and otherwise) in excess of 250° C. and while the aluminum oxide coating could withstand environmental conditions encountered in typical automotive applications such as salt spray, employing single strands of the copper conductor described in U.S. patent application Ser. No. 11/627,486 may require the attachment and positioning of hundreds or thousands of individual conductors on and throughout a typical automobile. It is desirable to have bundles of insulated copper wires having high heat tolerances that are resilient to environmental conditions and that have a high packing density permitted by thin insulation thicknesses. The embodiments of the invention described below address these and other problems.
In a first aspect of the invention, an insulated assembly of insulated electric conductors is disclosed. In a first embodiment, the assembly comprises a first plurality of insulated electric conductors. Each individual electric conductor has a copper core, a uniform thickness thin sheet of aluminum that is mechanically formed to envelope the copper core. Each individual electric conductor also has a single dielectric layer of aluminum oxide that is formed by anodizing the outer surface of a thin sheet of aluminum. The assembly further comprises a first aluminum layer that is mechanically formed to envelope the first plurality of insulated electric conductors. The assembly further comprises a first single dielectric layer of aluminum oxide that surrounds the first aluminum layer.
In an implementation of the first embodiment, the insulated assembly further comprises an additional one of the insulated electric conductors that is disposed proximate the first single dielectric layer of aluminum oxide. The insulated assembly further comprises a second aluminum layer that is mechanically formed to envelope the additional one of the insulated electric conductors and the first single dielectric layer of aluminum oxide. The insulated assembly further comprises a second single dielectric layer of aluminum oxide surrounding the second aluminum layer.
In another implementation, the insulated assembly further comprises a second plurality of the insulated electric conductors disposed proximate the first single dielectric layer of aluminum oxide. The insulated assembly also comprises a second aluminum layer that is mechanically formed to envelope the second plurality of the insulated electric conductors and the first single dielectric layer of aluminum oxide. The insulated assembly also comprises a second single dielectric layer of aluminum oxide surrounding the second aluminum layer. In a variation of this implementation, each of the insulated electric conductors of the second plurality may be disposed co-axially about the first single dielectric layer of aluminum oxide. Further, the second aluminum layer and the second single dielectric layer of aluminum oxide may be coaxial with the first single dielectric layer of aluminum oxide.
In another implementation, one of the copper cores comprises a generally circular cross section along substantially an entire longitudinal length of the copper core.
In another implementation, each of the copper cores comprises a generally circular cross section along substantially an entire longitudinal length of the copper core.
In another implementation of the first embodiment, one of the copper cores comprises a generally rectilinear cross section along substantially an entire longitudinal length of the copper core.
In another implementation of the first embodiment, each of the copper cores comprises a generally rectilinear cross section along substantially an entire longitudinal length of the copper core.
In another implementation, the insulated assembly further comprises a second plurality of the insulated electric conductors. The insulated assembly also comprises a second aluminum layer that is mechanically formed to envelope the second plurality of insulated electric conductors. The insulated assembly also comprises a second single dielectric layer of aluminum oxide surrounding the second aluminum layer. The insulated assembly further comprises a third aluminum layer that is mechanically formed to envelope the first single dielectric layer of aluminum oxide and the second dielectric layer of aluminum oxide. The insulated assembly also comprises a third single dielectric layer of aluminum oxide surrounding the third aluminum layer. In a variation of this implementation, each of the copper cores may comprise a generally circular cross section along substantially an entire longitudinal length of the copper core. In an alternate variation, each of the copper cores may comprise a generally rectilinear cross section along substantially a longitudinal length of the copper core. In a further variation, each insulated conductor of the first plurality of insulated conductors may be stacked one on top of the other and each insulated conductor of the second plurality of insulated conductors may be stacked one on top of the other. In some variations, the first plurality of insulated conductors and the second plurality of insulated conductors may be positioned side by side.
In a second embodiment of the first aspect of the invention, the assembly comprises a first plurality of insulated electric conductors. Each electric conductor has a copper core, a uniform thickness thin sheet of aluminum that is mechanically formed to envelope the copper core and a single dielectric layer of aluminum oxide that is formed by anodizing an outer surface of the thin sheet of aluminum. The insulated assembly may further comprise a first single dielectric layer of aluminum oxide that envelopes the plurality of insulated electric conductors. The first single dielectric layer is formed by completing anodizing a first uniform thickness thin sheet of aluminum that has been mechanically formed to envelope the plurality of insulated electric conductors.
In an implementation of the second embodiment, the insulated assembly further comprises an additional one of the insulated electric conductors disposed proximate the first single dielectric layer of aluminum oxide. The insulated assembly further comprises a second single dielectric layer of aluminum oxide that envelopes the additional one insulated electric conductor and the first single dielectric layer. The second dielectric layer may be formed by completely anodizing a second uniform thickness thin sheet of aluminum that has been mechanically formed to envelope the additional one insulated electric conductor and the first single dielectric layer.
In another implementation, the insulated assembly may further comprise a second plurality of the insulated electric conductors disposed proximate the first single dielectric layer of aluminum oxide. A second single dielectric layer of aluminum oxide may envelope the second plurality of the insulated electric conductors and the first single dielectric layer of aluminum oxide. The second single dielectric layer may be formed by completely anodizing a second uniform thickness thin sheet of aluminum that has been mechanically formed to envelope the second plurality of the insulated electric conductors and the first single dielectric layer. In a variation of this implementation, each of the insulated electric conductors of the second plurality may be disposed co-axially about the first single dielectric layer of aluminum oxide. Further, the second single dielectric layer of aluminum oxide is co-axial with the first single dielectric layer of aluminum oxide.
In another implementation of the second embodiment, the insulated assembly may further comprise a second plurality of the insulated electric conductors. The insulated assembly also includes a second single dielectric layer of aluminum oxide enveloping the second plurality of the insulated electric conductors. The second single dielectric layer may be formed by completely anodizing a second uniform thickness thin sheet of aluminum that has been mechanically formed to envelope the second plurality of the insulated electric conductors. The insulated assembly may further comprise a third single dielectric layer of aluminum oxide surrounding the first single dielectric layer of aluminum oxide and the second single dielectric layer of aluminum oxide. The third single dielectric layer may be formed by completing anodizing a third uniform thickness thin sheet of aluminum that has been mechanically formed to envelope the first single dielectric layer of aluminum oxide and the second single dielectric layer of aluminum oxide.
In another implementation of the second embodiment, each of the copper cores may comprise a generally rectilinear cross section along substantially an entire longitudinal length of the copper core.
In another aspect of the invention, a method of making an insulated assembly of insulated electric conductors is disclosed. In the first embodiment of the second aspect, the method includes providing a plurality of copper cores and enveloping each copper core with a uniform thickness thin sheet of aluminum. The method further comprises anodizing an outer surface of each thin sheet of aluminum to form a single dielectric layer of aluminum oxide to electrically insulate each copper core, thus forming a plurality of insulated electric conductors. The plurality of insulated electric conductors is enveloped in an aluminum layer comprising a uniform thickness thin sheet of aluminum and an outer surface of the aluminum layer is anodized to form a single dielectric layer of aluminum oxide to electrically insulate the plurality of insulated electric conductors.
The description herein makes reference to the accompanying drawing wherein like reference numerals refer to like parts through the several views, and in which:
Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily drawn to scale, some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for the claims and/or as a representative basis for teaching one skilled in the art to variously employ the present invention.
The present disclosure includes embodiments having various advantages. For example, embodiments of the present disclosure provide an insulated assembly of insulated electric conductors that is mechanically tough, chemically resistant, and suitable for operation at extreme operating and/or environmental temperatures hundreds of degrees higher than wire assemblies conventionally insulated with polymeric insulation. The single dielectric/insulating layer is robust against strain-related defects during mechanical forming and is economically viable to produce in large quantities and long continuous lengths. The mechanical toughness facilitates forming conductors of various cross-sectional geometries and gage-diameters.
The insulated assemblies of insulated electric conductors disclosed herein have desirable thermal conductivity to dissipate heat and to tolerate higher ohmic heating per square while resisting electrical and environmental degradation. Additionally, the single dielectric layer of aluminum oxide is resistant to external heating by many hundreds of degrees Celsius beyond conventional wire assemblies insulated with polymeric insulation.
Insulated assemblies disclosed herein are suitable for use, without limitation, in automotive applications and may be routed near or mounted on portions of automobiles such as exhaust systems and engine components having high heat output without substantial degradation in the insulated assemblies' conductivity. The single dielectric layer of aluminum oxide also advantageously provides a layer that is substantially impervious to salt spray and other environmental conditions that the undercarriage of a vehicle is exposed to during operating conditions.
Use of a uniform thickness thin sheet of aluminum with proper control of the anodizing process results in the formation of a single dielectric layer with a substantially smooth outer surface without holes or voids that can be mechanically formed to a plurality of similarly insulated electric conductors. Use of a thin, uniform thickness sheet of aluminum allows for close or dense packing of insulated electric conductors within an insulated assembly and also permits closer dense packing of multiple insulated assemblies thus affording a manufacturer compact packing options when routing insulated assemblies along an undercarriage of a vehicle or throughout various compartments within the vehicle.
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Uniform thickness thin sheet of aluminum 20 may have uniform thicknesses of between about 0.003 inches (76.2 microns) to 0.015 inches (381 microns) with a uniformity of plus or minus 0.005 inches (12.7 microns). Other dimensions may be suitable for particular applications consistent with the teachings of the present disclosure. However, the thickness must be selected consistent with the process for forming the aluminum to the core, anodizing the aluminum to form a dielectric layer, and subsequent forming of the insulated electric conductor to avoid failures that may include subsequent separation, flaking, pitting, etc. of the dielectric layer.
A mechanical cold-forming technique may be used to form aluminum sheet 20 about copper/copper alloy core 22. Other techniques or processes used to form aluminum sheet 20 to copper/copper alloy core 22 may include vacuum welding, radio frequency bonding, high pressure pressing and galling. A particular forming technique may vary depending upon a number of factors that may include the thickness of aluminum sheet 20, the geometry of copper/copper alloy core 22 and/or the particular ultimate application of the insulated electric conductor and the selected implementation of the anodizing process. In some embodiments, aluminum sheet 20 may be anodized prior to enveloping copper/copper alloy core 22. In other embodiments, aluminum sheet 20 is formed to copper/copper alloy core 22 prior to the anodization process.
Insulated electric conductors, represented generally by reference numeral 32 are made by forming sheet of aluminum 20 to envelope a selected copper or copper alloy core 22 with uniform thickness thin sheet of aluminum 20 and partially anodizing an outer surface of uniform thickness thin sheet of aluminum 20 to form a dielectric layer 34 of aluminum oxide that electrically insulates copper/copper alloy core 22, but is thermally conductive to dissipate heat. A thin layer 36 of electrically conductive aluminum surrounds copper/copper alloy core 22 and facilitates adhesion or bonding of dielectric layer 34 to core 22. Insulated electric conductor 38 is formed by enveloping stranded copper/copper alloy core 22 with uniform thickness thin sheet of aluminum 20 and partially anodizing an outer surface of aluminum sheet 20 to form a dielectric layer 34 of aluminum oxide. A similar process may be used to form electrically insulated conductor 40 using uniform thickness thin sheet of aluminum 20 envelope solid copper/copper alloy core 26. Similar processes may be used to form insulated electric conductors 42 and 44.
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Additional guide pulleys 64 and 66 may be used to direct wire 48 through an optional rinse 68 having a suitable solution or rinse agent 70 such dionized water, for example, before being collected by take-up spool 72, which may be driven by an appropriate motor (not shown). Rinse 68 may be used to remove any residual electrolytic agent 60 from wire 48 to facilitate the handling and to further retard or halt the oxidation process. The simplified process illustrated in
As discussed below, the embodiments of the invention described below entail gathering pluralities of the insulated electrical conductors 32 made using the above method, and bundling or assembling them in the various configurations described below, enveloping the various configurations in an additional layer or layers of uniform thickness thin sheets of aluminum 20 and repeating the simplified process illustrated in
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The first plurality of insulated conductors 74 is surrounded by a first aluminum layer 76 which has been mechanically formed to the first plurality of insulated conductor 74 in any one of the manners described above. A first single dielectric layer of aluminum oxide 78 surrounds first aluminum layer 76 to form an electrically insulating layer that is substantially impervious to environmental conditions such as salt spray, resilient to mechanical abrasions and thermally conductive to permit the dissipation of heat.
First aluminum layer 76 and first single dielectric layer of aluminum oxide 78 are formed by mechanically forming uniform thickness thin sheet of aluminum 20 about first plurality of insulated conductor 74 and then subjecting the assembly of the first plurality of insulated conductors 74 and the uniform thickness thin sheet of aluminum 20 to the process described above which is graphically depicted in
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At block 90, a plurality of copper/copper alloy cores 22 are provided. At block 92, each individual core is enveloped within a uniform thickness thin sheet of aluminum 20. At block 94, an outer surface of each thin sheet of aluminum 20 is anodized to form a dielectric layer of aluminum oxide surrounding each individual core. At block 96, the plurality of insulated electric conductors produced during the step corresponding to block 94 are enveloped in a uniform thickness thin sheet of aluminum. At block 98, an outer surface of the uniform thickness thin sheet of aluminum 20 is anodized to form a single dielectric layer of aluminum oxide surrounding the plurality of insulated electric conductors 20. Additional insulated electric conductors can be produced using the above process and assembled together in various configurations and enveloped in uniform thickness thin sheets of aluminum which are then anodized to form various configurations of insulated assemblies 73 disclosed in
While the best mode for carrying out the invention has been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.