Electrical terminal for flat flexible cable

Abstract

An electrical terminal (30) for mating with an exposed conductor (12) of a flat flexible cable (10) includes an electrical contact (32) and a crimping portion (40, 90) extending from the electrical contact in the longitudinal direction of the terminal to crimp to the conductor of the flat flexible cable. The crimping portion includes: a base (44, 94) defining an aperture (68, 69, 96) extending therethrough; and first and second sidewalls (46, 48, 91, 93) extending from the base and defining an opening (70) configured to receive a conductor. At least one of the first and second sidewalls has a sidewall protrusion (74, 76, 92) extending therefrom. The first and second sidewalls are foldable into the opening to crimp the conductor within the opening. In the crimped state of the crimping portion, the conductor is pressed into the aperture through the sidewall protrusion.

Description

Technical Field

[0001] This disclosure relates to electrical terminals, and more particularly to electrical terminals suitable for crimping conductors to 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., metal foil) 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 more capable of facilitating 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 can be achieved by applying an insulating material to either side of a pre-patterned thin foil conductor and then bonding the sides together via an adhesive to enclose the conductor within it. Current FFC terminals include piercing crimp terminals, where the sharp points of the terminal pierce through the insulation and adhesive material of the FFC in an attempt to establish a strong electrical connection with the embedded conductor.

[0005] However, these types of terminals have several drawbacks, partly due to the fragility of the thin foil conductor material itself, including much higher resistance compared to conventional round wire F-type crimping, inconsistent electrical connections between the conductor and the terminal, and mechanical unreliability over time in harsh environments.

[0006] Therefore, an improved electrical terminal and accompanying termination technology are needed to adapt FFC to these environments. Summary of the Invention

[0007] 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 the 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 aperture extending therethrough; and first and second sidewalls extending from the base. The base and sidewalls define an opening configured to receive the conductor of the flat flexible cable therein. At least one of the first or second sidewalls includes a sidewall protrusion extending therefrom, wherein the sidewall is foldable into the opening to crimp the conductor within the opening. In the crimped state of the crimping portion, the conductor is pressed into the aperture formed through the base via the sidewall protrusion.

[0008] The cable assembly according to embodiments 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 via a window or opening selectively formed in the insulating material, allowing a crimped portion of a conductive terminal to engage the conductor within the opening. The crimped portion includes a base defining at least one hole extending therethrough; and first and second sidewalls extending from the base. The base and sidewalls define openings configured to receive the exposed conductors therein, wherein at least one of the first or second sidewalls includes a sidewall protrusion extending therefrom. The sidewalls are foldable into the openings to crimp the conductors into the openings, wherein in the crimped state of the crimped portion, the conductors are pressed into the hole via the sidewall protrusions. Attached Figure Description

[0009] The invention will now be described by way of example with reference to the accompanying drawings, in which:

[0010] Figure 1 This is a top view of an exemplary FFC configured for use with terminals according to embodiments of this disclosure;

[0011] 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;

[0012] Figure 3 Is with Figure 2 The terminals and connector body mate Figure 1 A perspective view of the FFC;

[0013] Figure 4A This is a perspective view of the crimped portion of a terminal according to the first embodiment of the present disclosure in an uncrimped state;

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

[0015] Figure 4C It is in a crimping state. Figure 4A and 4B A perspective view of the crimped portion;

[0016] Figure 4D yes Figure 4C A front cross-sectional view of the crimped portion;

[0017] Figure 5A This is a top perspective view of the crimped portion of a terminal according to the second embodiment of the present disclosure in an uncrimped state;

[0018] Figure 5B yes Figure 5A Side view of the crimped portion;

[0019] Figure 5C It is in an uncrimped state. Figure 5A and Figure 5B A front cross-sectional view of the crimped portion; and

[0020] Figure 5D It is in a crimping state. Figure 5A and 5B A front cross-sectional view of the crimped portion. Detailed Implementation

[0021] 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 resulting in a complete lack of electrical contact between the terminal and 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.

[0022] The terminals according to embodiments of this disclosure can be configured for use with FFC, for example... Figure 1 An 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.

[0023] Conductor 12 may include a metal foil, such as copper foil on the order of 0.07 mm in thickness, this is merely an example, and can be patterned in any desired configuration. Insulating material 14, such as a polymeric insulating material, may be applied to either side of conductor 12 via an adhesive to form an embedded conductor arrangement. 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 conductor 12, thereby enabling its connectorization using terminals according to embodiments of this disclosure. Windows or openings may be formed in any desired location on insulating material 14 to expose portions of conductor 12 for easy termination. Additional openings 16 may be provided, configured to receive complementary features of associated connectors, as will be described in more detail herein.

[0024] 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 shown here for illustrative purposes only. As illustrated, 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.

[0025] 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. Distributed 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.

[0026] 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 FFC 10 (see...). Figure 1 The crimp portion 36 is configured to be crimped onto the conductor 12, for example, in a batch termination or crimping step, wherein the crimp portion 36 of each terminal 30 is crimped simultaneously, securing the terminal 30 and thereby the inner housings 26, 28 to the FFC 10.

[0027] The inner housings 26 and 28 may also define strain-relieving portions 37 and 38, configured to extend through the opening 16 in the FFC 10, for further securing the inner housings 26 and 28 to the FFC 10. Similarly, as shown, the piercing element 35 penetrates the insulating material 14 of the FFC 10 and may subsequently flatten or otherwise deform to further secure the terminal 30 to the FFC 10. In this way, the piercing element 35 and the strain-relieving portions 37 and 38 provide strain relief for the resulting connection, mechanically fixing the position of the FFC 10 relative to the terminal 30.

[0028] Figures 4A-4D 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...) Figure 4A and 4B 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 parts. Specifically, sidewall 46 includes a first part 56 and a second part 57 arranged adjacent to the first part. The first part 56 and the second part 57 may be continuous with each other, or they may be completely or partially separated from each other.

[0029] For example, a recess or protrusion 72 may be defined through the middle portion of the sidewall 46, wherein portions 56, 57 are located on the respective sides of the recess 72. The recess 72 is partially configured to facilitate a degree of independent movement between the first portion 56 and the second portion 57 during the crimping process. The first portion 56 and the second portion 57 have different overall heights, with the first portion 56 being higher than the second portion 57. Similarly, the second sidewall 48 includes a first portion 58 and a second portion 59, which are defined by a recess 73 that is at least partially defined therebetween. The first portion 58 and the second portion 59 may also have different heights, with the first portion 58 being shorter than the second portion 59. In this way, for each pair of opposing sidewall portions 56, 58 and 57, 59, the height of one sidewall is greater than that of the other opposing sidewall. This arrangement facilitates the crimping of the sidewalls in an overlapping manner, as described in detail herein.

[0030] refer to Figure 4C and 4DThe crimped portion 40 is shown in a crimped state, wherein the opposing sidewalls 46, 48 have been crimped from... Figure 4A and 4B The orientation crimping or deformation shown is in a generally parallel or crimped position relative to the base 44.

[0031] Side walls 46 and 48 can be folded or crimped sequentially. One complete side wall 46 or 48 is first deformed into the crimped position, and then another complete side wall 46 or 48 is folded over it (not shown). However... Figure 4C In one embodiment, during the crimping operation, the sidewalls 46 and 48 are staggered to distribute the force evenly when crimping the conductor within the terminal (not shown) and to promote its central positioning within the receiving space 70. More specifically, in one embodiment, a first portion 56 of the first position 46 is folded into the crimping position and contacts the conductor disposed within the receiving space 70. A second portion 59 of the second sidewall 48 is also folded into the crimping position and contacts the conductor. Subsequently, a first portion 58 of the second sidewall 48 and a second portion 57 of the first sidewall 46 are folded or crimped over the corresponding first portion 56 and second portion 58, so that they remain in contact with the conductor disposed within the terminal. Figure 4D An exemplary cross-sectional view of the crimped portion 40 in a crimped state is provided, including the conductor 100 crimped within the receiving space 70.

[0032] As described above, reliably crimping a thin conductor to an FFC requires a method to address the risk of failing to form a 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 in the underside of the base 44 and / or sidewalls 46, 48 of the crimp portion 40 to prevent any of the aforementioned failures.

[0033] Refer again Figure 4A The lower side of the second portion 59 of the second sidewall 48 includes a portion 81 that defines serrations or patterned recesses or protrusions formed thereon. The serrations are provided to further improve engagement with the conductor by potentially increasing the contact area and by enabling the second portion 59 to engage with the conductor even if any foreign matter, such as residues of insulating material or adhesive, may remain on the exposed conductor after the window or opening around it is formed. Another serrated portion 81 may be formed on the underside of the first sidewall portion 56, such as... Figure 4B As shown. It should be understood that these serrations can be formed on any and all surfaces of the crimp portion 40 without departing from the embodiments of the invention.

[0034] The crimping portion 40 also includes a protrusion formed on the bottom or side of the receiving opening 70 facing at least one portion of at least one sidewall thereon. Figures 4A-4DIn the illustrated embodiment, the first portion 56 of the first sidewall 46 and the second portion 59 of the second sidewall 48 each include corresponding protrusions 74, 76 formed thereon. In a particularly advantageous embodiment, the protrusions 74, 76 are formed on and extend from the serrated portion 81 of each sidewall. The protrusions 74, 76 may include hemispherical, dome-shaped, or other circular profiles, which may be elongated and extend in the axial direction of the terminal.

[0035] Still referencing Figures 4A-4D The crimping portion 40 includes an axially extending protrusion 60 that rises from the base 44 (having holes 68, 69 formed therethrough) into the receiving opening 70. More specifically, in the illustrated embodiment, the protrusion 60 includes a plurality of segments including a pair of external compression restraints 64 defined by a raised protrusion that extends vertically from the base 44 into the receiving opening 70.

[0036] Similarly, the central compression limiter 66 is defined by a protrusion extending generally between the outer compression limiters 64. In the illustrated embodiment, each compression limiter includes an externally curved or circular profile whose axis of curvature is generally parallel to the axial direction of the terminals and / or conductors disposed therein.

[0037] The external compression limiter 64 also includes a rounded end 65 extending in the corresponding vertical direction. For example... Figure 4A and 4C As shown, at least a portion of each external compression limiter 64 extends axially through the ends of the first and second sidewalls 46, 48, ensuring maximum contact area with the conductor crimped within the terminal. Partly due to their bending nature, the compression limiters are configured (i.e., sized and shaped) to compress the conductor under the force of the first and second sidewalls in a manner that prevents damage to the conductor. Furthermore, the increased height of the compression limiters ensures reliable electrical contact with the conductor at all times, resolving the aforementioned tolerance-related issues present in prior art crimping solutions. Additionally, the height of the compression limiters can be selected to allow adjustment of the crimping height and compression force for a given application (e.g., for conductors of different thicknesses).

[0038] Still referencing Figures 4A-4DThe base 44 of the crimping portion 40 includes holes 68, 69 formed between the outer compression limiter 64 and the central compression limiter 66. Each hole 68, 69 may include a generally square or rectangular profile with lateral edges extending across the base 44 to the corresponding sidewalls 46, 48. Each hole 68, 69 is defined by at least two raised edges on the top surface of the protrusion 60, extending in a direction transverse to or laterally to the axial direction of the terminal. In this way, the opening defining each hole 68, 69 on its top side facing the receiving space 70 includes a variable height, with its longitudinal edges arranged below the lateral or measuring edges, which rise up near the axial center of the crimping portion.

[0039] The protrusions 74 and 76 extending from the first sidewall 46 and the second sidewall 48 are positioned to correspond in position to the holes 68 and 69 when the crimping portion 40 is in the crimping state, such as... Figure 4D As shown. Protrusions 74, 76 facilitate strong electrical contact with the conductor crimped within the terminal. More specifically, as the conductor is crimped, the force applied by the protrusions 74, 76 to the top side of the conductor acts to push the conductor (e.g., conductive foil) into the corresponding holes 68, 69, engaging its peripheral edges to clamp the conductor between the edge of the hole and the surface and / or the bottom side of the protrusions 46, 48. This conductor-to-edge interaction breaks down oxides and other contaminants on the conductor to improve electrical contact, and, at least in part, due to the plastic deformation of the conductor, maintains the engagement even after the initial crimping pressure is released.

[0040] Figures 5A-5D A crimping portion 90 of a terminal according to another embodiment of the present disclosure is shown. In its uncrimped state, the crimping portion 90 includes a generally U-shaped body comprising a base 94 and two generally opposing sidewalls or wings 91, 93 extending from either side. A contact or conductor receiving opening or space is defined between the sidewalls 91, 93 and configured to receive an exposed conductor of the FFC (e.g., along the axial direction of the terminal) therein. Figure 1 and Figure 3 The conductor 12 shown. The base 94 defines a generally curved cross-section, as shown. Figure 5A and 5C As shown, its curvature axis extends approximately in the axial direction of the terminal.

[0041] The base 94 also defines a plurality of holes 96 formed therethrough. The holes 96 may be aligned in the axial direction of the terminal and evenly spaced along the length of the crimp portion 90. The holes may define tapered openings, wherein the opening of a hole adjacent to a receiving opening is smaller than the opening of a hole on the outer or convex side of the base 94, such as... Figure 5C As shown.

[0042] Each sidewall 91, 93 of the crimp portion 90 defines a protrusion 92 extending from its free end. In an exemplary embodiment, each protrusion 92 defines four side elements, wherein at least three of them taper as the sidewalls extend from the sidewalls 91, 93. The protrusions 92 are positioned aligned with the holes 96 in the axial direction of the terminal such that, in the crimped state of the crimp portion 90, the protrusions 92 are configured to penetrate into the openings 96, thus pushing the conductor 100 crimped within the terminal into these openings. More specifically, the opposing protrusions 92 formed on the respective sidewalls 91, 93 are each sized, shaped (e.g., tapered), and positioned to be deformable into the associated holes 96. In this way, each hole 96 is configured to receive at least a portion of two opposing protrusions 92 in the crimped state, such as Figure 5D As shown. This protrusion and hole engagement provides the same functionality as described above. Figures 4A-4D The similar benefits described.

Claims

1. An electrical terminal (30) for mating with the exposed conductor (12) of a flat flexible cable (10), comprising: Electrical contact (32); as well as A conductive crimp portion (40, 90) extending from the electrical contact (32) in the longitudinal direction of the terminal (30) to terminate the conductor (12) of the flat flexible cable (10), the crimp portion (40, 90) comprising: A conductive base (44, 94) defines a hole (68, 69, 96) extending through it in a direction transverse to the longitudinal direction; as well as Conductive first and second sidewalls (46, 48, 91, 93) extend from the base (44, 94) and define an opening (70) extending longitudinally for receiving a conductor (12). At least one of the first or second sidewalls (46, 48, 91, 93) has a sidewall protrusion (74, 76, 92) extending therefrom. The first and second sidewalls (46, 48, 91, 93) are independently foldable relative to the base and can be folded into the opening (70) to press the conductor (12) into the opening (70), wherein, in the pressed state of the pressed portion (40, 90), the conductor (12) is pressed into the hole (68, 69, 96) through the sidewall protrusion (74, 76, 92).

2. The electrical terminal (30) of claim 1, wherein each of the first and second sidewalls is foldable relative to the base along an axis extending in the longitudinal direction.

3. The electrical terminal (30) of claim 2, wherein the base further defines a base protrusion (60) that extends into the opening and extends along the base (44) in the longitudinal direction of the terminal (30), and includes a curved profile whose axis of curvature extends in the longitudinal direction of the terminal (30).

4. The electrical terminal (30) as claimed in claim 2, wherein the base protrusion (60) comprises: The first and second end base protrusions (64); as well as A central base protrusion (66) is arranged between the first and second end base protrusions (64). The holes (68, 69, 96) formed through the base (44) include a first hole (68) and a second hole (69), wherein the first hole (68) is arranged between the first end base protrusion (64) and the central base protrusion (66), and the second hole (69) is arranged between the second end base protrusion (64) and the central base protrusion (66).

5. The electrical terminal (30) as claimed in claim 4, wherein the sidewall protrusions (74, 76) include a first sidewall protrusion (74) aligned with the first hole (68) in the longitudinal direction of the terminal (30) and a second sidewall protrusion (76) aligned with the second hole (69) in the longitudinal direction of the terminal (30).

6. The electrical terminal (30) of claim 1, wherein the first sidewall (46) comprises a first portion (56) and a second portion (57), and the second sidewall (48) comprises a first portion (58) and a second portion (59) opposite to the first and second portions (56, 57) of the first sidewall (46), wherein recesses (72, 73) are formed to pass through each of the first and second sidewalls (46, 48) between the first portion (56, 58) and the second portion (57, 59).

7. The electrical terminal (30) as claimed in claim 6, wherein in the crimped state, the first portion (58) of the second sidewall (48) is folded over and overlaps the first portion (56) of the first sidewall (46), and the second portion (57) of the first sidewall (46) is folded over and overlaps the second portion (59) of the second sidewall (48).

8. The electrical terminal (30) of claim 7, wherein the first and second portions (56, 57, 58, 59) of each sidewall (46, 48) include different heights.

9. The electrical terminal (30) of claim 8, wherein the opposing first portions (56, 58) of the first and second sidewalls (46, 48) have different heights.

10. The electrical terminal (30) of claim 7, wherein at least one of the first and second portions (56) of the first sidewall (46) or the second portion (59) of the second sidewall (48) includes serrations on its side facing the opening (70).

11. The electrical terminal (30) of claim 10, wherein the sidewall protrusions (74, 76) are formed in the region of the serrations on at least one of a first portion (56) of the first sidewall (46) or a second portion (59) of the second sidewall (48).

12. The electrical terminal (30) as claimed in claim 11, wherein, When the crimped portion (40) is in the crimped state, the sidewall protrusions (74, 76) are configured to engage with the holes (68, 69).

13. The electrical terminal (30) of claim 1, wherein the sidewall protrusion (92) comprises a plurality of sidewall protrusions (92) extending from the free end of each of the first sidewall (91) and the second sidewall (93).

14. The electrical terminal (30) of claim 13, wherein the hole (96) comprises a plurality of holes (96) aligned in the longitudinal direction of the terminal (30), and wherein, in the crimped state of the crimped portion (90), each of the holes (96) is configured to receive a portion of at least two of the plurality of sidewall protrusions (92).

15. A cable assembly comprising: A flat flexible cable (10) includes a plurality of conductors (12) embedded within an insulating material (14), wherein a portion of each of the conductors (12) is exposed via selectively formed openings (21, 23, 25) in the insulating material (14); and A plurality of conductive terminals (30), each of the terminals (30) having a conductive crimp portion (40, 90) that at least partially engages with the openings (21, 23, 25) in the insulating material (14) and receives an exposed portion of a corresponding conductor (12), the crimp portion (40, 90) comprising: A conductive base (44, 94) defining at least one aperture (68, 69, 96) extending therethrough; and Extending from the base (44, 94) and through conductive first and second sidewalls (46, 48, 91, 93) formed in one of the openings in the insulating material, the base (44, 94) and the first and second sidewalls (46, 48, 91, 93) define a conductor opening (70) configured to receive a conductor (12) therein, at least one of the first or second sidewalls (46, 48, 91, 93) having a sidewall protrusion (74, 76, 92) extending therefrom, the first and second sidewalls (46, 48, 91, 93) being foldable into the conductor opening (70) to press the conductor (12) into the conductor opening (70), wherein, in the pressed state of the pressed portion (40, 90), the conductor (12) is pressed into the hole (68, 69, 96) through the sidewall protrusion (74, 76, 92).

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