Electrical terminal for flat flexible cable

Abstract

A cable assembly includes a flat flexible cable having a plurality of conductors embedded within an insulating material. A portion of each conductor is exposed through a selectively formed opening in the insulating material, allowing a crimp portion of a conductive terminal to engage the conductor within the opening. The crimp portion of the terminal includes a base defining a protrusion extending therefrom, and first and second side walls extending from the base. The base and first and second side walls define an opening configured to receive the conductor therein. The first side wall includes a first portion attached to the base and a second portion attached to the first portion at an end opposite the base. In a crimped state of the terminal, the first side wall is rotated into the opening such that the first portion at least partially surrounds the second portion, and the second side wall is rotated in a direction opposite the first portion such that the first portion at least partially surrounds the second portion for crimping the conductor within the opening and against the protrusion.

Description

Technical Field

[0001] This invention relates to electrical terminals, and more specifically, to electrical terminals suitable for crimping onto conductors of flat, flexible cables. Background Technology

[0002] As those skilled in the art will understand, a flat flexible cable (FFC) or flat flexible circuit is an electrical component consisting of at least one conductor (e.g., a metal foil conductor) embedded in a thin, flexible insulating strip. Flat flexible cables are gaining popularity in many industries due to their advantages over traditional “round wire” matings. Specifically, in addition to having a lower profile and lighter weight, FFCs are also significantly easier to implement for large circuit paths compared to round wire-based architectures. Therefore, FFCs are considered for many complex and / or high-capacity applications, including wire harnesses, such as those used in automotive manufacturing.

[0003] Implementing or integrating FFC in existing wiring environments presents significant challenges. In automotive applications, to name just one example, FFC-based wiring harnesses may need to mate with hundreds of existing components, including sub-harnesses and various electronic devices (e.g., lights, sensors, etc.), each with established (and in some cases standardized) connector or interface types. Therefore, a key obstacle hindering the implementation of FFC in these applications includes the need to develop fast, robust, and low-resistance termination technologies that enable FFC to interface with these existing connections.

[0004] A typical FFC (Foil-Fit Crimping) is achieved by applying insulation to either side of a pre-patterned foil conductor and then bonding the sides together with an adhesive to enclose the conductor within. Current FFC terminals include piercing crimp terminals, where the sharp points of the terminal pierce the insulation and adhesive of the FFC in an attempt to establish a strong electrical connection with the embedded conductor. However, these types of terminals have several drawbacks, partly due to the inherent fragility of the foil conductor material, including significantly higher resistance compared to conventional round wire F-type crimps, inconsistent electrical connectivity between the conductor and the terminal, and mechanical unreliability over time in harsh environments.

[0005] Therefore, it is necessary to improve the electrical terminals and associated terminal technology to adapt FFC to these environments. Summary of the Invention

[0006] According to embodiments of this disclosure, a terminal is provided for mating with an exposed conductor of a flat flexible cable. The terminal includes an electrical contact and a crimping portion extending from the electrical contact in a longitudinal direction of the terminal to crimp to the conductor of the flat flexible cable. The crimping portion includes a base defining at least one protrusion extending therefrom; and first and second sidewalls extending from the base. The first sidewall includes a first portion attached to the base and a second portion attached to the first portion at an end opposite to the base. The base and the sidewall define an opening configured to receive the conductor of the flat flexible cable therein. In the crimped state of the terminal, the first sidewall is wound or rotated in a first direction and enters the opening such that the first portion at least partially surrounds the second portion for crimping the conductor within the opening and abutting against the protrusion, and the second sidewall is wound or rotated in a direction opposite to the first portion such that the first portion at least partially surrounds the second portion of the second sidewall.

[0007] The cable assembly according to an embodiment of the present disclosure includes a flat flexible cable having a plurality of conductors embedded within an insulating material. A portion of each conductor is exposed through an opening selectively formed in the insulating material, allowing a crimped portion of a conductive terminal to engage with the conductor within the opening. The crimped portion of the terminal includes a base defining at least one protrusion extending therefrom; and first and second sidewalls extending from the base. The base and the first and second sidewalls define an opening configured to receive a conductor therein. The first sidewall includes a first portion attached to the base and a second portion attached to the first portion at an end opposite to the base. In the crimped state of the terminal, the first sidewall is wound around itself and substantially wound into the opening, such that the first portion at least partially surrounds the second portion for crimping the conductor within the opening and abutting against the protrusion, and the second sidewall rotates or winds in a direction opposite to the first portion, such that the first portion at least partially surrounds the second portion. Attached Figure Description

[0008] The invention will now be described by way of example with reference to the accompanying drawings, in which:

[0009] Figure 1 This is a top view of an exemplary FFC configured for use with terminals according to embodiments of this disclosure;

[0010] Figure 2 This is a perspective view of a plurality of terminals installed in an exemplary connector body according to an embodiment of the present disclosure;

[0011] Figure 3 Is with Figure 2 The terminals and connector body mate Figure 1 A perspective view of the FFC;

[0012] Figure 4AThis is a perspective view of the crimped portion of a terminal according to the first embodiment of the present disclosure in an uncrimped state;

[0013] Figure 4B yes Figure 4A Front cross-sectional view of the crimped portion;

[0014] Figure 4C yes Figure 4A and 4B Front cross-sectional view of the crimped portion; and

[0015] Figure 5 This is a perspective view of the crimped portion of a terminal according to a second embodiment of the present disclosure. Detailed Implementation

[0016] Exemplary embodiments of the invention will now be described in detail with reference to the accompanying drawings, wherein like reference numerals denote like elements. However, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make this disclosure thorough and complete, and to fully convey the concepts of this disclosure to those skilled in the art.

[0017] Reliably crimping terminals onto the thin conductor of an FFC requires a method to address the risk of failing to form a proper (or any) electrical contact with the conductor, or damaging the conductor by applying excessive pressure. This has proven difficult, partly due to the thin nature of the FFC conductor compared to the tolerances of typical crimp terminals. For example, with a thickness less than one-tenth of a millimeter (mm) (e.g., 0.07 mm), the crimp height tolerance can easily exceed the conductor thickness, potentially leading to a complete lack of electrical contact between the terminal and the conductor, or crushing or damaging the conductor, even under proper crimping operations. As will be explained in more detail herein, embodiments of this disclosure aim to overcome these difficulties by providing crimpable terminals capable of achieving reliable, low-resistance connections in a large number of termination or crimping operations.

[0018] The terminals according to embodiments of this disclosure can be configured for use with FFC, for example... Figure 1An exemplary portion of the FFC 10 is shown. As illustrated, the FFC 10 typically includes a plurality of conductors 12 embedded within an insulating material 14. The conductors 12 may include metal foil, such as copper foil on the order of 0.07 mm in thickness, which is merely an example and can be patterned in any desired configuration. The insulating material 14, such as a polymer insulating material, may be applied to either side of the conductors 12 via an adhesive material to form an embedded conductor arrangement. The exemplary FFC 10 includes a plurality of segments 20, 22, 24, each segment containing a plurality of conductors 12. Corresponding windows or openings 21, 23, 25 are selectively formed or defined near the respective ends of segments 20, 22, 24 to expose the conductors 12, thereby enabling their connectorization using terminals according to embodiments of the present disclosure. The windows or openings may be formed at any desired location in the insulating material 14 to expose portions of the conductors 12 for easy termination. Additional openings 16 may be provided and configured to receive complementary features of the associated connector, as will be described in more detail herein.

[0019] refer to Figure 2 An exemplary inner housing 26, forming part of the connector, is provided for securing to... Figure 1 The FFC 10 is provided as an example only. As shown, the inner housing 26 is pre-mated with a plurality of conductive terminals 30 according to embodiments of the present disclosure. Each terminal 30 typically includes an electrical contact or mating end 32, in this case a female mating end, configured to receive a corresponding male terminal to establish an electrical connection. The mating end 32 may include one or more locking features 33 configured to engage with the inner housing 26 to secure the terminal 30 thereto. The rear end 34 of the terminal 30 opposite the mating end 32 may include piercing elements 35, embodied herein as a pair of sharp teeth. Arranged between the mating end 32 and the rear end 34 is a crimping portion 36 configured to elastically deform to crimp onto a conductor disposed therein.

[0020] Figure 3 The diagram illustrates an intermediate step in the connectorization process of FFC 10. As shown, FFC 10 is placed on top of multiple connectors, including... Figure 2 The connector has an inner housing 26 and two second inner housings 28. Each connector's terminal 30 receives an exposed conductor 12 within its respective crimp portion 36, which extends through windows 21, 23, 25 formed in the insulating material 14 of the FFC10 (see...). Figure 1The crimping portion 36 is configured to crimp onto the conductor 12, for example, in a batch termination or crimping step, wherein the crimping portion 36 of each terminal 30 is crimped simultaneously, securing the terminal 30 and thus the inner housings 26, 28 to the FFC 10. The inner housings 26, 28 may also define strain-relieving portions 37, 38, configured to extend through the opening 16 in the FFC 10, for further securing the inner housings 26, 28 to the FFC 10. Similarly, as shown, the piercing element 35 penetrates the insulating material 14 of the FFC 10 and may subsequently be flattened or otherwise deformed to further secure the terminal 30 to the FFC 10. In this way, the piercing element 35 and the strain-relieving portions 37, 38 provide a strain-relieving form for the resulting connection, mechanically securing the position of the FFC 10 relative to the terminal 30.

[0021] Figures 4A-4C Terminals configured for use with FFC according to this disclosure are shown (e.g. Figure 2 and Figure 3 An embodiment of the crimping portion 40 of terminal 30 is shown; the remaining terminals are not shown. (See reference...) Figures 4A-4C In its uncrimped state, the crimped portion 40 includes a generally U-shaped body 42 comprising a base 44 and two generally opposing sidewalls or wings 46, 48 extending from either side in a direction generally perpendicular to the base 44. A contact or conductor receiving opening or space 70 is defined between the sidewalls 46, 48 and configured to receive an exposed conductor of the FFC therein along the axial direction of the terminal (e.g., Figure 1 and Figure 3 (Conductor 12 shown). Each sidewall or wing 46, 48 may be defined by two portions. Specifically, the first sidewall 46 includes a first portion 56 extending from and adjacent to the base 44, and a second portion 57 extending from the first portion. Figure 4B As shown, in the unpressed state, the first and second portions 56, 57 can extend in different directions relative to the base 44. More specifically, the first portion 56 can extend substantially perpendicularly from the base 44, or, in the illustrated embodiment, inclined in a direction substantially away from the center of the press-fit portion 40. The second portion 57 includes a curved end extending along the length of the sidewall 46 and having a curvature axis oriented in the longitudinal direction of the terminal. Thus, the curved end of the second portion 57 defines a convex surface and a concave surface. The curved end of the second portion 57 can also gradually taper in thickness from the end of the first portion 56 to its free end, which extends in the direction of the receiving opening. Similarly, the second sidewall 48 includes first and second portions 58, 59, each having features similar to those of the first sidewall 46 described above, the details of which will not be repeated.

[0022] The tilting and / or bending characteristics of Parts 56 and 58 and Parts 57 and 59 facilitate crimping operations, which include wrapping, rolling, or curling of each sidewall. More specifically, refer to... Figure 4C The crimped portion 40 is shown in a crimped state, wherein each of the opposing sidewalls 46, 48 has been crimped from... Figure 4A and 4B The orientation shown is a crimped configuration. As shown, the first and second portions 56, 57 of the first sidewall 46 have been deformed radially or helically, with the second portion rolled up or curled into the receiving opening 70 in a generally clockwise manner. As shown, the free end of the second portion 57 can be rotated at least about 270 degrees, preferably about 360 degrees, about an axis extending longitudinally along the terminal length, such that its angular orientation relative to the crimped portion 44 is approximately equal to its angular orientation before the crimping operation. Thus, the first portion 56 generally surrounds the second portion 57 disposed therein. The second sidewall 48 is deformed in a manner similar to the first sidewall 46, with its second portion 59 wrapped around the first portion 58, for example, the first portion generally surrounding the second portion.

[0023] The sidewalls 46, 48 can be deformed or crimped simultaneously, allowing for faster termination compared to multi-step crimping processes for other terminal types. In a particularly advantageous embodiment, the deformation of the first and second sidewalls 46, 48 in a rolling or spiral manner can be performed during the initial steps of the crimping process and before the sidewalls 46, 48 are engaged with the conductor disposed within the receiving opening 70. This ensures that the orientation or arrangement of the conductor within the opening 70 is unaffected by the initial sidewall deformation process and avoids potential damage (e.g., tearing) to the fragile conductor. Once the rolled-up sidewalls are formed, one or more subsequent crimping operations or movements involve pushing or pressing the rolled-up sidewalls 46, 48 toward or against the base 44 and engaging the conductor. More specifically, still referring to... Figure 4C In the crimped state, the conductor 100 is crimped within the resulting space 101 defined between the receiving opening between the respective side of each of the first and second sidewalls 46, 48 (i.e., the outside of the crimped portion in the non-crimped state) and the base 44.

[0024] Refer again Figure 4A The outer sides of the first and second sidewalls 46, 48 may include serrations or serrated portions 80 formed or defined thereon. The serrations 80 may be positioned on the sidewalls 46, 48 to, in the crimped state of the terminals, such as Figure 4CAs shown, it is typically adjacent to or joined to a conductor disposed within the opening 70. In addition to improving electrical connection or contact with the conductor, the serrations 80 prevent the conductor from shifting relative to its ideal position within the opening 70 during crimping. A serrated or sawtooth-like portion 81 defining a pattern of protrusions or teeth may be formed on the base 44, including its protruding features as detailed below.

[0025] As described above, reliably crimping a thin conductor to an FFC requires a method to address the risk of failing to make proper electrical contact with the conductor or damaging the conductor by applying excessive pressure. Embodiments of this disclosure address this problem by introducing several additional features on or within the base 44 of the crimp portion 40 to prevent either of these failures.

[0026] Still referencing Figures 4A-4C The crimping portion 40 includes an axially extending protrusion 64 rising from the base 44 into the receiving opening 70, wherein only one of them is in Figure 4A As shown in the diagram, a second corresponding protrusion having features similar to the shown protrusion 64 is disposed on the opposite end of the crimp portion 40 and aligned with the shown protrusion 64 along the axial direction of the terminal. The protrusion 64 includes an externally curved or rounded profile having an axis of curvature substantially parallel to the axial alignment of the terminal and / or the conductor to be disposed therein. The protrusion 64 also defines two rounded ends 65 extending axially in their respective directions. Partly due to this curved nature, the protrusion 64 is configured (i.e., sized and shaped) to compress the conductor in a manner that prevents damage under the forces from the first and second sidewalls 46, 48 of the crimp. Furthermore, the increased height of the protrusion ensures reliable electrical contact with the conductor at all times, resolving the aforementioned tolerance-related problems of prior art crimping solutions. Additionally, the height of the protrusion can be selected to allow for adjustment of the crimping height and compression force for a given application (e.g., for conductors of different thicknesses).

[0027] The base 44 may include a serrated portion 82 formed therein, such as serrations formed on the surface of the protrusion 64. In addition to improving electrical contact with the conductor arranged in the opening 70 in the crimped state of the terminal, the serrated portion 82 of the base 44 serves to hold the conductor in the proper position within the opening 70 and prevent undesirable displacement, for example, during crimping operations performed on the sidewalls 46, 48 of the terminal.

[0028] like Figure 5As shown, another embodiment of the crimping portion 90 includes an axially extending protrusion 92 rising from the base 91 into the receiving opening 72. In the illustrated embodiment, the protrusion 92 includes a plurality of segments including a pair of external compression restraints 94 defined by a raised protrusion extending vertically from the base 91 into the receiving opening 72. Similarly, a central compression restraint 96 is defined by a protrusion extending generally between the external compression restraints 94. Each of the compression restraints 94, 96 includes an externally curved or rounded profile having a curvature axis generally parallel to the axial alignment of the terminal and / or the conductor to be disposed therein. The external compression restraints 94 also include rounded ends 95 extending axially in their respective directions. As shown, at least a portion of each external compression restraint 94 extends axially beyond the ends of the first and second sidewalls to ensure maximum contact area with the conductor crimped within the terminal. The sidewalls of the illustrated embodiment include features similar to those described above. Figures 4A-4C The features described herein will not be described in detail here.

[0029] Still referencing Figure 5 The protrusion 92 also includes a protruding portion or pusher 98 formed between the outer compression restraint 94 and the central compression restraint 96. Each protrusion 98 may also include a curved or circular profile extending into the receiving opening 72 and having an axis of curvature oriented parallel to the terminal axial direction. In one embodiment, the protrusion 98 is higher than the compression restraints 94, 96, and thus extends further vertically into the receiving opening or space 72. Each protrusion 98 defines at least two edges on the top surface of the protrusion 92 that extend in a direction transverse to the terminal axial direction and facilitate securing and electrically contacting the conductor disposed within the receiving opening in a crimped state of the terminal. Despite the difference in height, the protrusions 98 and the compression restraints 94, 96 form a generally continuous circular protrusion 92 extending axially within the receiving opening 72.

[0030] The foregoing has illustrated some possibilities for implementing the invention. Many other embodiments are possible within the scope and spirit of the invention. Therefore, the foregoing description should be considered illustrative rather than restrictive, and the scope of the invention is given by the appended claims and their full scope. For example, it should also be understood that embodiments of this disclosure may include any combination of the features described above, such as various combinations of compression restraints and spring devices, and are not limited to the exemplary devices illustrated in the drawings.

[0031] Furthermore, the indefinite articles “a” and “an” preceding the elements or components of the present invention are intended to not limit the number of instances, i.e., the number of times the elements or components appear. Therefore, “a” or “an” should be understood to include one or at least one, and the singular form of an element or component also includes the plural, unless the number is obviously singular.

[0032] The term “invention” or “the present invention” as used herein is a non-limiting term and does not refer to any single embodiment of a particular invention, but includes all possible embodiments described in this application.

Claims

1. An electrical terminal for mating with the exposed conductor of a flat, flexible cable, comprising: Electrical contacts; and A crimping portion, extending from the electrical contact in the longitudinal direction of the terminal, is used for crimping onto the conductor of a flat, flexible cable, the crimping portion comprising: The base defines at least one protrusion extending therefrom; A first sidewall extending from a base, the first sidewall comprising a first portion and a second portion, the first portion being attached to the base, and the second portion being attached to the first portion at an end of the first portion opposite to the base; and The second sidewall extending from the base The base and the first and second sidewalls define an opening configured to receive the conductor. In the unpressed state of the terminal, the first sidewall defines serrations on its side opposite to the opening. In the pressed state of the terminal, a first portion and a second portion of the first sidewall are rotated into the opening, the first portion at least partially surrounding the second portion for pressing the conductor into the opening and between the serrations and the protrusion. The protrusion extends along the base in the longitudinal direction of the terminal, and includes a curved profile having a curvature axis extending in the longitudinal direction of the terminal. The protrusion includes: First and second end protrusions; A central protrusion disposed between the first and second end protrusions; A first intermediate protrusion disposed between a first end protrusion and a central protrusion; and A second intermediate protrusion disposed between the second end protrusion and the central protrusion. The first and second intermediate protrusions extend into the opening further than the first and second end protrusions and the central protrusion; The base includes serrations formed on the surface of the protrusion.

2. The electrical terminal according to claim 1, wherein, The second sidewall includes a first portion and a second portion that are respectively opposite to the first portion and the second portion of the first sidewall, wherein in the crimped state, the first sidewall rotates into the opening in a first direction relative to the base, and the second sidewall rotates into the opening in a direction opposite to the first direction, such that the first portion of the second sidewall at least partially surrounds the second portion of the second sidewall.

3. The electrical terminal according to claim 2, wherein, In the crimped state, the second portions of the first and second sidewalls are rotated at least 270 degrees relative to the angular orientation of the base from the uncrimped state of the terminal, with each second portion wrapped around a corresponding one of the first portions.

4. The electrical terminal according to claim 2, wherein, A first portion of the first sidewall extends from the base in a direction away from the opening, and a second portion of the first sidewall includes a curved profile extending from the end of the first portion in a direction toward the opening.

5. The electrical terminal according to claim 4, wherein, The curvature axis of the second portion of the first sidewall extends in the longitudinal direction of the terminal.

6. The electrical terminal according to claim 5, wherein, The thickness of the second portion of the first sidewall gradually decreases from the first portion to its free end.

7. A cable assembly, comprising: A flat, flexible cable includes multiple conductors embedded in an insulating material, wherein a portion of each conductor is exposed through selectively formed openings in the insulating material; and A plurality of conductive terminals, each terminal having a crimp portion, the crimp portion at least partially engaging with an opening in an insulating material and receiving an exposed portion of a corresponding conductor, the crimp portion comprising: The base defines at least one protrusion extending therefrom; A first sidewall extending from a base, the first sidewall comprising a first portion and a second portion, the first portion being attached to the base, and the second portion being attached to the first portion at an end opposite to the base; and A second sidewall extending from the base, the base, and the first and second sidewalls define an opening configured to receive a conductor. In the crimped state of the terminal, the first part and the second part of the first sidewall rotate into the opening to crimp the conductor into the opening and abut against the protrusion, with the first part at least partially surrounding the second part. The protrusion extends along the base in the longitudinal direction of the terminal, and includes a curved profile having a curvature axis extending in the longitudinal direction of the terminal. The protrusion includes: First and second end protrusions; A central protrusion disposed between the first and second end protrusions; A first intermediate protrusion disposed between a first end protrusion and a central protrusion; and A second intermediate protrusion disposed between the second end protrusion and the central protrusion. The first and second intermediate protrusions extend into the opening further than the first and second end protrusions and the central protrusion; The base includes serrations formed on the surface of the protrusion.

8. The cable assembly according to claim 7, wherein, In the uncrimped state of the terminal, at least one of the first or second sidewalls defines a serration on its side opposite to the opening, wherein, in the crimped state of the terminal, the conductor is crimped between the serration and the protrusion.

9. The cable assembly according to claim 8, wherein, The second sidewall includes a first portion and a second portion respectively opposite to a first portion and a second portion of the first sidewall, wherein in the crimped state, the first sidewall rotates into the opening in a first direction relative to the base, and the second sidewall rotates into the opening in a direction opposite to the first direction, such that the first portion of the second sidewall at least partially surrounds the second portion of the second sidewall.

10. The cable assembly according to claim 9, wherein, In the crimped state, the second portions of the first and second sidewalls are rotated at least 270 degrees relative to the angular orientation of the base from the uncrimped state of the terminal, with each second portion wrapped around a corresponding one of the first portions.

11. The cable assembly according to claim 7, wherein, A first portion of the first sidewall extends from the base in a direction away from the opening, and a second portion of the first sidewall includes a curved profile extending in a direction toward the opening.

12. The cable assembly according to claim 11, wherein, The curvature axis of the second portion of the first sidewall extends in the longitudinal direction of the terminal.

13. The cable assembly according to claim 12, wherein, The thickness of the second portion of the first sidewall gradually decreases from the first portion to its free end.

14. A method of manufacturing a cable assembly according to any one of claims 7 to 13, comprising the following steps: The conductor of the flat flexible cable is arranged in an opening between the first sidewall, the second sidewall, and the base of the crimped portion of the conductive terminal; The respective free ends of the first sidewall and the second sidewall are rotated into the opening of the conductive terminal such that the free end of each of the first sidewall and the second sidewall is at least partially surrounded by the remaining portion of the respective one of the first sidewall and the second sidewall. and After rotating the free ends of the first and second sidewalls, the first and second sidewalls are pressed together in the direction toward the base to capture the conductor within the opening and between the sidewalls and the protrusion defined on the base and extending into the opening.

15. The method of claim 14, further comprising the step of forming serrations on at least one of the first sidewall or the second sidewall opposite to the opening in the uncrimped state of the terminal, wherein the step of crimping the first sidewall and the second sidewall further comprises crimping a conductor between the serrations and the protrusion.

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