1. Field of the Invention
This invention relates to methods for coupling two or more components and, in particular, to a method for coupling plastic coated metal tubing using connectors and a thermoplastic bonding material to form a fluid tight, pressurized joint.
2. Discussion of Related Art
Motor vehicles may include various fluid handling systems, such as, but not limited to, fuel systems, power steering systems, heating and cooling systems, and hydraulic braking systems. These fluid handling systems may require the attachment of various tubular bodies, connectors and other components to create robust seals and fluid tight, pressurized joints for fluid handling.
A variety of methods are known for joining components of a fluid handling system. Ashland, Inc. has previously developed a process under the registered trademark “EMABOND” using induction welding to join two thermoplastic bodies. This process uses a bonding agent or resin disposed between the thermoplastic bodies and having metallic particles. A. Raymond Corp. has developed a process reflected in Published PCT patent application WO 01/21996 in which a tubular body is joined to a plastic connector using a meltable adhesive. Each of these methods, while satisfactory for its intended purpose, is used to join single material components (e.g., a thermoplastic body to another thermoplastic body or to a metallic body).
The inventors herein have recognized the benefits of using multi-layer tubing, and specifically plastic coated metal tubing, in fluid handling systems. See commonly assigned U.S. patent application Ser. No. 11/042,014 filed Jan. 25, 2005, the entire disclosure of which is incorporated herein by reference. The inventors have further recognized a need for a method for coupling components in a fluid handling system in which multi layer tubing and connectors are used.
The present invention relates to a method for coupling components of a fluid handling system.
A method in accordance with the present invention includes the step of providing a first component, the first component comprising a tubular body having a metallic layer and a polymeric layer. The method also includes the step of providing a second component, the second component comprising a connector. The connector defines a first port. The method also includes the steps of providing a thermoplastic material proximate the first port of the connector and positioning one of the first and second components relative to another of the first and second components such that the tubular body of the first component is proximate the first port of the connector. Finally, the method includes the step of energizing a first conductor to deform the first thermoplastic material and form a bond between the first and second components.
A method in accordance with the present invention has significant advantages relative to conventional manufacturing methods for coupling fluid system components. The method provides an efficient process for coupling plastic coated metal tubing and connectors while creating a fluid tight, pressurized joint.
These and other advantages of this invention will become apparent to one skilled in the art from the following detailed description and the accompanying drawings illustrating features of this invention by way of example.
Referring now to the drawings wherein like reference numerals are used to identify identical components in the various views,
Component 12 may comprise relatively rigid tubing for use in fluid handling. Component 12 defines a fluid passageway 18 in which fuel or another fluid may be stored and/or through which fuel or another fluid may be transported. Component 12 includes a metallic layer 20 and a polymeric layer 22. In the illustrated embodiment, metallic layer 20 is disposed inwardly of polymeric layer 22. It should be understood that additional laminate layers may be formed between layers 20, 22 and that either of layers 20, 22 may include a plurality of sublayers without departing from the spirit of the present invention.
Layer 20 may comprise steel. In a preferred embodiment layer 20 comprises aluminum. Layer 22 is polymeric and may comprise a plastic and, in particular, a thermoplastic. Layer 22 may or may not include a metallic or carbon or other non-metallic filler. In a preferred embodiment, layer 22 comprises nylon. Nylon refers to a family of polyamides generally characterized by the presence of the amide group, —CONH. In a preferred embodiment, the nylon is of a type known as nylon 12. It should be understood, however, that the type of nylon may vary and may be conductive (e.g., through the addition of carbon black) or non-conductive. Layer 22 may be pre-bonded to the layer 20 and may be extruded over the layer 20. In one constructed embodiment, the component is formed from nylon coated aluminum tubing sold under the registered trademark “HYCOT” by Hydro Aluminum Hycot USA, Inc. The aluminum layer of the tubing has a thickness of about 0.1 to about 1.2 mm. The nylon layer of the tubing has a thickness of between about 80 and about 500 microns and may measure about 150 microns.
Component 14 comprises a connector for connecting other components (e.g., for connecting component 12 to another component 12 or a different component). Component 14 may be made from a polymer such as a plastic. Component 14 defines at least one opening or port 24, but typically defines multiple ports used to connect multiple fluid conduits. In one embodiment of the invention, component 14 comprises a tee connectors having three separate ports 24. Component 14 may define one or more fluid passageways 26 extending between ports 24.
Thermoplastic bonding material 16 is provided to join components 12, 14. Material 16 may comprise a polyamide such as nylon or a partially aromatic polyamide. It should be understood, however, that other conventional bonding materials may be used. Material 16 is provided proximate a port 24 of component 14 where component 12 is to be joined to component 14. In the illustrated embodiment, one end of component 12 is disposed within one end of component 14 defining port 24 and material 16 is disposed on an inner surface of component 14 between component 14 and layer 22 of component 12. Material 16 may be relatively rigid and formed in a predefined shape and positioned within or around one end of connector 14 defining port 24. Alternatively, material 16 may be injected molded with connector 14 as connector 14 is formed.
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The method may continue with the step 404 of providing a thermoplastic material 16 proximate the port of the connector. Step 404 may include several substeps. In one embodiment of the invention step 404 may include the substeps 406, 408 of forming material 16 into a predefined shape and positioning material 16 relative to the port of the connector. The predefined shape may be complementary to the shape of the port (e.g., the inner and/or outer surface of the connector) and/or may be designed to enable secure fastening of material 16 to the connector. In an alternative embodiment, step 404 may include the substep 410 of injecting material 16 into a predefined position relative to the port of the connector.
The method may continue with the step 412 of positioning one of the components relative to another of the components such that the tubular body of plastic coated metal component is proximate the port of the connector. Referring to
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The inventive method may finally include the step 422 of energizing a conductor to deform material 16 and form a bond between the components. The conductor may, for example, comprise a coil through which current is fed from a power source. The inventive method thus employs a form of induction welding. The inventors herein have recognized that the resulting electromagnetic field providing inductive energy to the metallic layer of the plastic coated metal component will result in heat transfer from the metallic layer to the polymeric layer and the thermoplastic material 16 and, at sufficient levels, will result in deformation of the polymeric layer and/or material 16 through melting to form a bond between the components. The resulting bond has significant strength. Further, the bond forms a hermetic seal such that fluid handling components may have fluid inlets and outlets sealingly coupled as shown in
The inventive method may be used to form a coupling between two components. In accordance with one aspect of the invention, however, the inventive method may be used to couple additional components. For example, the method may be used co couple multiple plastic coated metal tubes using a connector. The method may therefore continue with the step 424 of providing another component comprising a tubular body and having a metallic layer and a polymeric layer. The method may further continue with the step 426 of providing additional thermoplastic material proximate another port of the connector. The material may be the same material or a different material relative to the material used to join the connector to the first plastic coated metal tube. The method may further continue with the step 428 of positioning one of the additional plastic coated metal tube component and the connector relative to the other as discussed hereinabove such that the additional plastic coated metal tube is proximate another port of the connector. Finally, the method may include the step 430 of energizing either the conductor used to connect the first plastic coated metal tube and the connector or another conductor.
The method may be used to couple multiple connectors to opposite ends of a plastic coated metal tube. The method may therefore continue with the steps 432, 434 of providing another component comprising a connector defining a port and a thermoplastic material the port. The material may again be the same material or a different material relative to the material used to join the first connector to the plastic coated metal tube. The method may further continue with the step 436 of positioning one of the additional connector component and the plastic coated metal tube component relative to the other as discussed hereinabove such that the plastic coated metal tube is proximate the port of the newly added connector. Finally, the method may include the step 438 of energizing either the conductor used to connect the plastic coated metal tube and the first connector or another conductor. Again,
A method in accordance with the present invention has significant advantages relative to conventional manufacturing methods for coupling tubular bodies. The method provides an efficient process for coupling plastic coated metal tubing and connectors while creating fluid tight, pressurized joints. For example, multiple joints can be formed simultaneously using the inventive method and the inventive method avoids the need for brazing and other costly manufacturing processes. The inventive method also allows the formation of a strong, fluid tight joint that is capable of withstanding pressurized applications without the need for complex mechanical seals
While the invention has been shown and described with reference to one or more particular embodiments thereof, it will be understood by those of skill in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.