Flat flexible cable assembly with integrally-formed sealing members

A flat flexible cable assembly includes a flat flexible cable having one or more substantially rectangular conductors encompassed within an insulating sheath. An overmold encapsulates and is secured to a portion of the flat flexible cable in an area in which the insulating sheath has been stripped. One or more sealing members are integrally-formed with the overmold and encapsulates and is secured to each stripped conductor to form a seal. The overmold and the sealing member(s) may be made of the same material by using a one-step process. Alternatively, the overmold and sealing member(s) may be made of different material by using a two-shot process. A method of manufacturing the flat flexible cable assembly is disclosed.

TECHNICAL FIELD

The present invention generally relates to a flat flexible cable, and more particularly, to a flat flexible cable including an overmold with integrally-formed sealing members.

BACKGROUND OF THE INVENTION

Flexible flat cables are used to an increasing degree in automobile manufacture as a replacement for ordinary cable harnesses consisting of round conductors. Various advantages are gained during use of the flexible flat cable harnesses in contrast to round cable harnesses. By using rectangular conductors, greater amounts of current can be transferred in comparison with round conductors. Therefore, rectangular conductors may be smaller, without comprising performance. The result is a reduction in weight and space allocation for flexible flat cables.

Moreover, individual cable seals consisting of ribbed cables are commonly utilized as an acceptable method for sealing individual cables in wet areas of the automotive electrical distribution system (EDS). Typically, each cable is isolated and sealed to the round wire insulation by a seal crimp at the electrical interface terminal and then collectively received into an electrical connector. Sealing each individual cable is conventionally done through an automated process.

However, despite the advantages of flexible flat cables, they do not lend themselves to being sealed individually using the automated process referenced above. Currently, in order to individually seal flexible flat cables, each cable must be sealed using an adhesive or a sealant during a secondary process. Such methods may be cumbersome and may add material and labor cost to the manufacturing process.

SUMMARY OF THE INVENTION

The inventors of the invention have recognized these and other problems associated with the flexible flat wire cables. To this end, the inventors have invented a flat flexible cable assembly comprising a flat flexible cable including a substantially rectangular conductor; an overmold encapsulating a portion of the substantially rectangular conductor; and a sealing member integrally-formed with and extending from the overmold, wherein the sealing member encapsulates the substantially rectangular conductor to form a seal.

A method of manufacturing a flat flexible cable assembly comprising a flat flexible cable including a substantially rectangular conductor, the method comprising the steps of:placing a flat flexible cable assembly within a mold tool; andintroducing an overmold material into the mold tool and covering a portion of the flat flexible cable to form an overmold that encapsulates a portion of the flat flexible cable and to form a sealing member integrally-formed with the overmold,

wherein the sealing member encapsulates the substantially rectangular conductor to form a seal.

DETAILED DESCRIPTION

In an exemplary embodiment, a flat flexible cable assembly may be used to connect electrical components (not shown) in “wet” areas of an automotive electrical distribution system (not shown). These “wet” areas are known in the industry, and may include, for example, parts of the engine where fluids are present.

Referring now toFIGS. 1 and 2, a flat flexible cable assembly is generally shown at10according to an exemplary embodiment. The cable assembly10comprises a flat flexible cable11including a plurality of conductors12encapsulated by an insulating sheath14. Each conductor12may be substantially rectangular in cross-sectional shape. The insulating sheath14is made of a material known in the art that is capable of electrically insulating the conductors12from one another. According to an exemplary embodiment, the conductors12and the sheath14may be manufactured by using a co-extrusion process.

The conductors12may be made from any conductive material, such as, for example, aluminum, copper, or the like. The insulating sheath14is known in the art, and may be manufactured from any number of materials. For example, the sheath14may be made of polymeric materials, such as polyvinylchloride (PVC), and the like. Factors to take into consideration when deciding upon the material properties of the insulating sheath14include, amongst others, the maximum operating voltage of the rectangular conductors12and the temperature of the environment where the flat cable assembly10may be located.

A terminal18that provides an electrical connection point is formed by stamping and forming in a progressive die. Attachment of the terminal is accomplished by stripping the insulating sheath14at one end of each conductor12and crimping, or welding the appropriate portion of the terminal to conductor12. As illustrated in the embodiment, the flat flexible cable assembly10includes two conductors12and two terminals18. However, it can be appreciated that the invention is not limited to the number of conductors12and terminals18, and that the invention can be practiced with any desired number of conductors12and terminals18.

Referring toFIG. 2, the insulating sheath14includes a means for providing a discontinuity in the insulating sheath14. For example, the discontinuity may be in the form of one or more barrier slots24formed in the insulating sheath14proximate to the overmold26. In another example, the discontinuity may be in the form of slits, and the like. The discontinuity of the insulating sheath14provides an interruption or “hazardous path” to prevent moisture from wicking from one terminal to another without causing a complete disruption in the function of the cable assembly10. As illustrated, the barrier slots24are generally rectangular in shape. However, it can be appreciated that barrier slots24are not limited to a rectangular shape and may be any desired shape. In addition, it can be appreciated that while only two conductors are shown, there can be a barrier slot between each of additional adjacent multiple conductors and proximate to the overmold26.

According to an aspect of the invention, the cable assembly10includes an overmold26that encapsulates a portion of the cable assembly10and includes one or more sealing members28integrally-formed with the overmold26that encapsulates each conductor12at the point it attaches to terminal18to form a seal for each individual conductor12. Specifically, the overmold26and the one or more integrally-formed sealing members28are formed by using an overmold process. During the overmold process, the cable assembly10is placed within a mold tool (not shown) and the overmold material is introduced into the mold tool such that the overmold material covers a portion of the conductors12at the point it attaches to terminal18and also to cover a portion of the insulating sheath14proximate the stripped, bare conductors12. Once the overmold material has been cured, the overmold26is positively secured to the insulating sheath14while having integrally-formed individual sealing members28encapsulating each conductor12that has been stripped of the insulating sheath14. The sealing member28may be formed in a well-known manner by including a configuration (not shown) in the mold tool, which may be impressed into the tool, that allows each terminal18of the plurality of conductors12to be individually sealed by the sealing member28during the overmold process.

It can be appreciated that the overmold material used in forming the overmold26may be any flexible plastic molding material, such as a thermoplastic elastomer (TPE) material, and the like. Further, it can be appreciated that overmold26may also contain insulation properties, similar to electronically insulating sheath14. As shown inFIG. 2, the overmold26does not completely cover the barrier slot(s)24, thereby allowing the barrier slots24to provide a hazardous path preventing migration of moisture between adjacent conductors. The sealing member28may be manufactured from the same material as the overmold26. Alternatively, the sealing member28may be manufactured from a different, second material by using a two-shot process.

As described above, the overmold process serves a dual purpose: 1) to form the overmold26that is positively secured to the insulating sheath14of the flat flexible cable assembly10, and 2) to form the individual sealing member(s)28that extend from the overmold26and encapsulate each conductor12to form an individual seal around each conductor12.

As illustrated, the one or more sealing members28may comprise one or more ribs30that extend circumferentially from a central, tubular member32. The tubular member32encompasses the conductors12and extends over a portion of terminals18. In the illustrated embodiment, the ends of terminals18remain exposed. While three ribs30are shown, it can be appreciated that the invention can be practiced with any desired number of ribs30that are capable of providing an adequate seal for each conductor12.

Referring now toFIG. 3, the terminals18may be inserted into a sealed connector34for an automotive electrical component such as, a power outlet, or the like. The terminals18of the cable assembly10may be inserted into a corresponding number of individual cavities36of the sealed connector34to engage connection points (not shown) of the sealed connector34. Once the terminals18of the cable assembly10have been properly inserted into the sealed connector34, the ribs30of each individual sealing member28engage an inner surface38of a respective cavity36. Therefore, the diameter40of the ribs30for each sealing member28is approximately equal to, or may be slightly larger than the diameter42of each individual cavity36of the sealed connector34. As a result, the sealing member28of cable assembly10is positively retained by the sealed connector34, while sealing each individual cavity36from containments, including fluid containments. Thus, the sealing member28that is integrally-formed with the overmold26seals against access, leakage, or passage of fluids into the sealed connector34, particularly when the cable assembly10is utilized in the “wet” areas of the automobile.

It can be appreciated that the invention can be practiced with the sealing member28having any desired shape or size, so long as sealing member28engages and seals the individual cavities36of the sealed connector34and provides an adequate seal. For example, the ribs30may be omitted and the sealing member28may have a diameter40approximately equal to, or may be slightly larger than the diameter42of each individual cavity36of the sealed connector34.

The embodiments disclosed herein have been discussed for the purpose of familiarizing the reader with novel aspects of the invention. Although preferred embodiments of the invention have been shown and described, many changes, modifications and substitutions may be made by one having ordinary skill in the art without necessarily departing from the spirit and scope of the invention as described in the following claims.