Patent Application
20070023129
1. Field of the Invention
This invention relates to methods for coupling two or more components and, in particular, to a method for coupling polymeric tubing to polymeric coated metal tubing while providing 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 to create robust seals and fluid tight, pressurized joints for fluid handling.
A variety of methods are known for joining tubular bodies of a fluid handling system. For example, ITT Industries, Inc. has previously developed a process under the trademark “POSIBOND” that utilizes spin welding to join two tubular bodies. Spin welding does not, however, allow for the simultaneous creation of multiple joints and therefore requires an undesirable amount of time to create multiple joints. Ashland, Inc. has previously developed a process under the registered trademark “EMABOND” using induction welding to joint two thermoplastic bodies. This process, however, requires the use of a bonding agent or resin disposed between the thermoplastic bodies and having metallic particles.
The inventors herein have recognized a need for a method for coupling components in a fluid handling system that will minimize and/or eliminate one or more of the above-identified deficiencies.
The present invention relates to a method for coupling first and second tubular bodies.
A method in accordance with the present invention includes the step of providing a first tubular body. The first tubular body is made from a polymer. The method also includes the step of providing a second tubular body. The second tubular body is formed as a laminate having a metallic layer and a polymeric layer. The method further includes the step of positioning one of the first and second tubular bodies relative to the other of the first and second tubular bodies. The method further includes the step of energizing a conductor proximate the first and second tubular bodies to generate heat transfer from the metallic layer of the second tubular body to the polymeric layer of the second tubular body to deform the first polymeric layer of the second tubular body and bond the second tubular body to the first tubular body.
A method in accordance with the present invention has significant advantages relative to conventional manufacturing methods for coupling tubular bodies. The method allows two tubular bodies to be joined together without the use of a bonding agent or other intermediary. The method also allows multiple, fluid tight joints to be formed simultaneously thereby reducing assembly time.
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, FIGS. 1 illustrates one embodiment of a fluid coupling 10A formed in accordance with the present invention. Fluid coupling 10A may be provided to transport fluid in a fluid handling system of a motor vehicle. Fluid handling systems constructed in accordance with the present invention may be particularly adapted for use in an automobile or light truck, but it should be understood that the inventive method described herein could be used for a variety of fluid handling systems for vehicular and non-vehicular applications. Coupling 10A includes at least a pair of tubular bodies 12A, 14A.
Tubular body 12A provides flexible tubing for use in fluid handling. Body 12A is made from a polymer such as a thermoplastic and may be made of nylon. Body 12A may be cylindrical in shape defining a circular fluid passageway 16. Body 12A defines at least one opening 18 configured for insertion of tubular body 14A. Tubular body 12A may define multiple openings 18 (e.g, at opposite longitudinal ends of body 12A or at an intermediary point along body 12A) to allow interconnection of multiple bodies similar to body 14A. Tubular body 12A may comprise monowall tubing as illustrated in
Referring again to
Layer 34 is metallic and may comprise steel. In a preferred embodiment layer 34 comprises aluminum. Layer 36 is polymeric and may comprise a plastic and, in particular, a thermoplastic. Layer 36 may or may not include a metallic or carbon or other non-metallic filler. In a preferred embodiment, layer 36 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 36 may be pre-bonded to the layer 34 and may be extruded over layer 34. In one constructed embodiment, body 14A, 14B, or 14C 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(s) of the tubing has a thickness of between about 80 and about 500 microns and may measure about 150 microns.
Bodies 14A, 14B, 14C may be straight throughout their longitudinal length. Referring to
Referring now to
The inventive method may continue with the step 50 of positioning at least one of tubular bodies 12A, 14A, relative to the other of tubular bodies 12A, 14A. In accordance with one embodiment of the invention, step 50 may include the substep 52 of inserting tubular body 14A into opening 18 of tubular body 12A (see
Prior to forming the sealed joint between bodies 12A (or 12B or 12C or 12D), 14A (or 14B or 14C), it may be desirable to apply a clamping load in the area of the joint to be formed. Accordingly, the inventive method may include the step 64 of applying a clamping load to the interface between bodies 12A (or 12B or 12C or 12D), 14A (or 14B or 14C). The load may be applied using any of a variety of conventional tools and/or methods known in the art. The load may also be applied at multiple locations along bodies 12A (or 12B or 12C or 12D), 14A (or 14B or 14C).
The inventive method continues with the step 66 of energizing a conductor proximate the tubular bodies 12A (or 12B or 12C or 12D), 14A (or 14B or 14C). 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 34 of tubular body 14A will result in heat transfer to polymeric layer(s) 36 and, at sufficient levels, will result in deformation of the polymeric layer(s) 36 through melting. This results in one or more bonds or joints or weld rings 68 between tubular body 14A an inner annular surface 54 of tubular body 12A (or between tubular body 14B and outer annular surface 60 of tubular body 12A or between tubular body 14C and the walls of recess 28 of tubular body 12D). Accordingly, step 66 may include the substep of forming one or more weld rings 68 between tubular bodies 12A (or 12B or 12C or 12D), 14A (or 14B or 14C). Referring to
The inventive method may be used to form a coupling between two tubular bodies 12A (or 12B or 12C or 12D), 14A (or 14B or 14C). In accordance with one aspect of the invention, however, the inventive method may be used to couple additional tubular bodies. Accordingly, the method may continue with the step 70 of positioning another tubular body relative to two other tubular bodies. For example, another tubular body 14A or 14C may be inserted into an opposite end of any of tubular bodies 12A, 12B, 12C, 12D. Alternatively, another tubular body 12A may be inserted into an opposite end of tubular body 14B. The method may further continue with the step 72 of energizing one of (i) the conductor used in coupling the first two tubular bodies and (ii) a second conductor, proximate the third tubular body and the tubular body to which it is being joined.
A method in accordance with the present invention has significant advantages relative to conventional manufacturing methods for coupling tubular bodies. The method allows two tubular bodies to be joined together without the use of a bonding agent or other intermediary. The method also allows multiple, fluid tight joints to be formed simultaneously thereby reducing assembly time. Further, the inventive method forms a strong, fluid tight joint that is capable of withstanding pressurized applications without the need for complex mechanical seals, while simultaneously reducing the cost and time of conventional manufacturing processes.
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.
