JP7557183B2 - Flat conductor cable connection terminal structure - Google Patents

Description

The present invention relates to a connection terminal structure for a flat conductor cable that is connected to an electronic component or electronic device.

Many electric wires, or conductor wires, are used in the wiring of electronic products and the electrical systems of automobiles. When multiple conductor wires are arranged together in a limited space, flexible flat cables (hereinafter also abbreviated as FFCs) are used, which have multiple flat conductor wires and a flexible insulating coating that covers the conductor wires. On the other hand, flexible printed circuit boards (hereinafter also abbreviated as FPCs) are used to electrically connect electronic devices to each other. The connection terminals of flat conductor cables, such as FFCs and FPCs, in which flat conductor wires are embedded in an insulating material, are connected to the connection terminals of electronic devices, etc.

In order to connect the conductor wires of the FFC to the conductor wires of the electronic device, a connector is attached to the connection end of the FFC described in Patent Document 1, and the conductor terminal portion of the FFC described in Patent Document 2 is connected by solder to the conductor terminal portion of the electronic component. As described in Patent Document 2, in order to solder the connection terminal portion of the FFC to the connection terminal portion of the electronic component, a slit is provided in the base film, which is an insulating coating, positioned between the connection terminal portions of the FFC. When the connection terminal portion of the FFC and the connection terminal portion of the electronic component are brought into close contact with each other and the preliminary solder is melted to perform soldering, even if the solder flows out from between the connection terminal portions, the solder is made to flow downward through the slit. This makes it possible to prevent the connection terminal portions of the FFC from shorting out due to the solder.

Patent document 3 describes a display device for electronic devices that has a display unit that is electrically connected to the main printed circuit board, and a connector land serving as a connection terminal for an FPC provided on the liquid crystal is connected to a contact spring connector serving as a connection terminal for the main printed circuit board. A slit is provided at the end of the FPC so that it can follow steps without bending the end. Patent document 4 describes an electrical connector that connects a display glass substrate and an FPC, and an oval hole is provided at the end of the FPC into which a positioning pin provided on the glass substrate is inserted.

JP 2003-112584 A Utility Model Publication No. 60-147175 JP 2001-350422 A JP 2001-351703 A

FFC has flat conductor wires embedded in a strip-shaped insulating coating made of flexible resin, and has the flexibility to bend easily. For this reason, FFC is often used as a cable for transmitting and receiving electrical signals between a movable part such as a printer head and a fixed main body device. In FFC, multiple conductor wires are embedded in the insulating coating in a flat state, and the exposed conductor wires at the end of the cable are also arranged on a flat surface, so the conductor spacing is short based on the voltage and current standards used, and the overall width is kept small by preventing expansion. For this reason, it is often used for low-voltage and low-current transmission, and is rarely used at the voltage and current values of general circular cross-section wires.

If the allowable voltage and current values that can be applied to conductor wires could be expanded, it would be possible to use FFCs in sliding and moving parts of mounting machines, such as moving parts such as the rotating parts of robots. However, if the distance between conductors is not increased in the same way as the conductor cross-sectional area, problems such as short circuits will occur, and as a result, the width dimension of the FFC will increase, making it impossible to fit the FFC into the wire routing space of the installed equipment.

Traditionally, there has not been much demand for smaller and lighter electronic devices in manufacturing facilities that manufacture electronic devices, or in communication facilities. However, as equipment operates faster and functions more, functional parts are being added, and the number of electric wires increases, resulting in a shortage of space for arranging the wires, and there is a need to make the wires themselves lighter and thinner.

The present invention aims to provide a connection terminal structure for a flat conductor cable that can reduce the width dimension of a flat conductor cable in which multiple conductor wires are embedded in an insulating coating.

In order to solve the above problems, the present invention provides a connection terminal structure for a flat conductor cable as described in claim 1. The connection terminal structure for a flat conductor cable includes a plurality of conductor wires and an insulating coating covering the conductor wires, the connection terminal structure comprising: protruding ends at an end of the flat conductor cable, the plurality of conductor wires being parallel to one another and exposed beyond an end face of the insulating coating; slits formed in the end of the insulating coating and positioned between adjacent conductor wires; and a terminal member made of an insulating material and functioning as a connector, the terminal member comprising a first connection portion arranged on one side of the flat conductor cable and a second connection portion connected to the first connection portion via a hinge portion and disposed on the other side of the flat conductor cable, the terminal member comprising an exposed portion that exposes the protruding ends of the conductor wires, and a shielding protrusion portion that is inserted into the slit and into a portion over the entire length between the exposed protruding ends of the conductor wires.

The present invention as set forth in claim 2 is characterized in that in the invention as set forth in claim 1 , a protective film is provided on at least one of both surfaces of the end portion of the insulating coating.

The present invention as set forth in claim 3 is characterized in that, in the invention as set forth in claim 2 , a reinforcing piece is provided on the protective film protruding toward the longitudinal center of the flat conductor cable, so that when the flat conductor cable is bent, stress concentration on the flat conductor cable is dispersed to the reinforcing piece.

According to the present invention, a slit is formed between the conductor wires at the end of the insulating coating of the flat conductor cable, and a terminal member provided at the end of the flat conductor cable is provided with a shielding protrusion that is inserted into the slit and a portion between the protruding ends of the conductor wires over the entire length of the terminal member, thereby making it possible to increase the creepage distance between the exposed conductor wires and reduce the spacing between the conductor wires, thereby making it possible to reduce the width of the flat conductor cable and make it more compact.

1 is a perspective view showing an end of a flat conductor cable in which a slit is formed in an end of an insulating coating. FIG. 1 is a perspective view showing a connection end of a flat conductor cable provided with a terminal member; 11 is a perspective view showing, by hatching, a shielding protrusion portion provided on a terminal member. FIG. 3A is a plan view showing a flat conductor cable as a comparative example, and FIG. 3B is a plan view showing the flat conductor cable shown in FIG. 2 . 11 is a perspective view showing a modified flat conductor cable in which protective films are provided on both ends of the insulating coating. FIG. 5A is a plan view of FIG. 5, FIG. 5B is a side view of FIG. 5, and FIG. 13 is a perspective view showing an end portion of a modified flat conductor cable and a terminal member attached thereto in a separated state. FIG. 8 is a perspective view showing a connection terminal of a flat conductor cable having a terminal member attached to the end shown in FIG. 7 . FIG. 11 is a perspective view showing an end portion of a flat conductor cable according to another modified example, and a terminal member attached thereto, in a separated state. 10 is a perspective view showing a connection terminal of a flat conductor cable having a terminal member attached to the end shown in FIG. 9 . 11 is a perspective view showing, by hatching, one of the shielding protrusions in the terminal member shown in FIGS. 9 and 10 . FIG. FIG. 13 is a perspective view showing a connection end portion of a flat conductor cable according to still another modified example. 13A is a side view showing a flat conductor cable as a comparative example, and FIG. 13B is a side view showing a flat conductor cable in which a reinforcing piece is provided on a protective film as shown in FIG. 12. FIG. FIG. 13 is a perspective view showing a flat conductor cable having a reinforcing piece according to a modified example.

Below, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings for explaining the embodiment, the same components are generally given the same reference numerals, and repeated explanations will be omitted.

Figure 1 shows the connection terminal structure of a flat conductor cable 10 constituting a flexible flat cable (FFC) as an example of a flat conductor cable. The flat conductor cable 10 has a plurality of flat conductor wires 11 and a flexible insulating coating 12 that covers the conductor wires 11. This flat conductor cable 10 has three conductor wires 11, but the number of conductor wires 11 embedded inside the insulating coating 12 is not limited to three depending on the width dimension of the insulating coating 12, and any number of conductor wires 11 can be embedded inside the insulating coating 12.

Each conductor wire 11 has a protruding end 14 formed to protrude outward beyond the end face 13 of the insulating coating 12, and the protruding ends 14 are parallel to each other. At the end of the insulating coating 12, a slit 15 is formed between adjacent conductor wires 11. In the insulating coating 12 incorporating three conductor wires 11, two slits 15 are formed parallel to the conductor wires 11. A notch 16 is formed on both sides in the width direction of the insulating coating 12. Note that this notch 16 has the function of preventing a prevention protrusion provided on the connector (not shown) from fitting into it when the flat conductor cable 10 is mated with a mating connector to prevent it from coming loose.

2 is a perspective view showing a connection terminal structure of the flat conductor cable 10 shown in FIG. 1, in which a terminal member 21 made of an insulating material is provided at the end of the flat conductor cable 10, and the terminal member 21 is integrally molded at the end of the flat conductor cable 10. The terminal member 21 is made of an insulating material and is integrally molded with the flat conductor cable 10 using a molding die. The terminal member 21 has an exposed portion 22 for connection that exposes the protruding end 14 to the outside, and the exposed protruding end 14 at the exposed portion 22 is connected to a connection terminal of a cable or electronic device (not shown). In this way, the terminal member 21 functions as a connector. Furthermore, a notch portion 23 is formed in the terminal member 21 in correspondence with the notch portion 16 formed in the insulating coating 12. Note that, like the notch portion 16 described above, this notch portion 23 also has a function of preventing the flat conductor cable 10 from coming loose when the flat conductor cable 10 is mated with a mating connector (not shown) by fitting a prevention protrusion provided on the connector into the notch portion 22.

When the terminal member 21 is integrally molded on the end of the flat conductor cable 10 shown in FIG. 1, as shown in FIG. 3, the shielding protrusions 24 are inserted into the slits 15 and also between the protruding ends 14. In FIG. 3, the shielding protrusions 24 provided on the terminal member 21 are shown by hatching.

In this way, the slit 15 is provided by trimming the base portion closer to the longitudinal center of the flat conductor cable 10 than the exposed conductor portion, rather than the portion that exposes the protruding ends 14 of the conductor wires 11 of the flat conductor cable 10, and the terminal member 21 is provided with a portion over the entire length between the protruding ends 14 of the conductor wires 11 and a shielding protrusion 24 that is inserted into the slit 15, thereby making it possible to increase the creepage distance between the exposed conductor wires . The creepage distance is the shortest distance along the shielding protrusion 24 between one conductor wire 11 and the nearest other adjacent conductor wire 11, and increasing the creepage distance also makes it possible to increase the antenna distance, thereby reducing the width dimension without compromising electrical function, thereby enabling the miniaturization of an FFC equipped with the flat conductor cable 10.

Figure 4(A) is a plan view showing a flat conductor cable 10a shown as a comparative example, and Figure 4(B) is a plan view showing the flat conductor cable 10 of the present invention shown in Figure 1. In the conventional flat conductor cable 10a shown in Figure 4(A) as a comparative example, if the conductor spacing W needs to be set to 3 mm due to electrical specifications, the overall width is D. In contrast, if the shielding protrusion 24 is inserted between the slit 15 and the protruding end 14, the creepage distance between the conductors can be increased, so that the conductor spacing w can be reduced to 1 mm as shown in Figure 4(B), and in a flat conductor cable 10 having three conductor wires 11, the overall width d can be set to (D-4) mm. In the flat conductor cable 10 shown in Figure 4(B), the length e of the slit 15 is 1 mm.

In this way, when a terminal member 21 having the shape shown in FIG. 3 is provided by insert molding at the connection end of the flat conductor cable 10, a wall is formed between the conductor wires 11 by the shielding protrusion 24 inserted into the slit 15, making it possible to miniaturize the flat conductor cable 10 without changing the electrical specifications.

Figure 5 shows a modified flat conductor cable, in which protective films 17 are provided on both surfaces of the end of the insulating coating 12, as shown in Figures 5 and 6 (B). The protective film 17 does not have to be provided on both surfaces of the end of the insulating coating 12, but may be provided on one surface of the end, as shown in Figure 3 (C), and is provided on at least one surface of the insulating coating 12.

In this way, by providing a protective film 17 on the end of the insulating coating 12, it is possible to prevent the insulating coating 12 from being affected by heat when the terminal member 21 is molded by insert molding, thereby improving the quality of the connection terminal of the cable.

Figure 7 is a perspective view showing the end of a modified flat conductor cable 10 and the terminal member 21 attached thereto in a separated state, and Figure 8 is a perspective view showing the connection terminal of the flat conductor cable 10 with the terminal member 21 assembled to the end shown in Figure 7.

This terminal member 21 is a molded product having a first connection part 25 arranged against one side of the flat conductor cable 10 and a second connection part 26 arranged against the other side, and both connection parts 25, 26 are connected so as to be freely opened and closed via a hinge part 27. Engagement claws 28 are provided on both sides in the width direction at the opening and closing end of the first connection part 25, and engagement grooves 29 into which the respective engagement claws 28 engage are provided in the second connection part 26.

The first connection part 25 is formed with an exposed part 22 for exposing the protruding end 14 of the conductor wire 11, and a communication hole 30 communicating with the exposed part 22 is formed in the first connection part 25. When attaching the terminal member 21 to the end of the flat conductor cable 10, the protruding end 14 is inserted into the communication hole 30 and the first connection part 25 and the second connection part 26 are combined, so that the connection terminal of the flat conductor cable 10 is in a state in which the protruding end 14 is exposed in the exposed part 22, as shown in FIG. 8. The protruding end 14 is connected to a connection terminal of a cable or electronic device (not shown). The exposed part 22 may be provided in the second connection part 26.

One of the first connection portion 25 and the second connection portion 26 is provided with a shielding protrusion 24, as in the terminal member 21 of the integrally molded type shown in FIG. 3, and the other is provided with a recess into which the shielding protrusion 24 fits. However, in FIGS. 7 and 8, the shielding protrusion 24 is omitted. Even in this embodiment in which the open-close terminal member 21 processed in a separate process is attached to the end of the flat conductor cable 10, the shielding protrusion 24 is inserted between the slit 15 and the protruding end 14, so that the creepage distance between the conductor wires 11 can be increased and the antenna distance can also be increased. This makes it possible to reduce the width of the flat conductor cable 10 without compromising electrical function, thereby making it possible to miniaturize an FFC equipped with a flat conductor cable.

Furthermore, as shown in FIG. 7, by providing protective films 17 on both sides of the end of the insulating coating 12, damage to the insulating coating 12 and the conductor wire 11 can be suppressed even if a large load is applied to the insulating coating 12 during the installation of the molded terminal member 21 to the end of the flat conductor cable 10.

Figure 9 is a perspective view showing the end of a modified flat conductor cable 10 and the terminal member 21 attached to it in a separated state, and Figure 10 is a perspective view showing the connection terminal of the flat conductor cable 10 with the terminal member 21 attached to the end.

The terminal member 21 includes a terminal body 31 made of an insulating material and a connector terminal 32 made of a conductive material and attached to the terminal body 31. Three connector terminals 32 are provided corresponding to the three conductor wires 11, and the terminal member 21 is a terminal member that serves as a dedicated terminal block. Each connector terminal 32 is connected to the protruding end 14 of the flat conductor cable 10 and, via the connector terminal 32, to a connection terminal 33 of an electronic device (not shown).

A first screw member 34 for fastening the protruding end 14 to the connector terminal 32 is provided on the terminal body 31 of the terminal member 21, and a second screw member 35 for fastening the connection terminal 33 to the connector terminal 32 is provided on the terminal body 31. The fastening method between the protruding end 14 and the connector terminal 32 may be such that the protruding end 14 is sandwiched between the connector terminal 32, or a mounting hole through which the screw member 34 passes may be provided in the protruding end 14. Similarly, a mounting hole through which the screw member 35 passes may be provided in the connection terminal 33.

As shown in Figures 9 and 10, the terminal body 31 is provided with shielding protrusions 24, similar to the terminal member 21 described above, and the terminal body 31 is provided with shielding walls 36 that are connected in a straight line to each of the shielding protrusions 24 and provide shielding between the connection terminals 33, and a reinforcing wall 37 is provided between the shielding protrusions 24 and the shielding walls 36 that are arranged in a straight line.

Figure 11 is a drawing showing the cross-sectional shape of one of the two shielding protrusions 24 shown in Figures 9 and 10, and the cross-sectional shape is shown with hatching. In this way, even in the terminal member 21, which is a dedicated product, the shielding protrusions 24 are inserted between the slits 15 and the protruding ends 14, so the creepage distance between the conductor wires 11 can be increased and the antenna distance can also be increased. Furthermore, if protective films 17 are provided on both sides of the end of the insulating coating 12, damage to the insulating coating 12 and the conductor wire 11 can be suppressed even if a large load is applied to the insulating coating 12 during the installation work of the terminal member 21 to the end of the FFC 10.

Figure 12 is a perspective view showing the connection end of a flexible flat cable that is yet another modified example, in which the protective film 17 provided on both sides of the insulating coating 12 is provided with a reinforcing piece 18 that protrudes toward the center of the flat conductor cable 10 in the longitudinal direction. The terminal member 21 provided at the end of the flat conductor cable 10 is integrally molded as in Figure 2, but may also be a molded product as shown in Figures 7 and 8, or a dedicated product as shown in Figures 9 and 10.

As shown in FIG. 12, providing a reinforcing piece 18 at the end of the flat conductor cable 10 can increase the cable strength when a bending load is applied to the terminal member 21.

Figure 13 (A) is a side view showing a flat conductor cable 10 without a reinforcing piece 18 as a comparative example, and Figure 13 (B) is a side view showing a flat conductor cable 10 with a reinforcing piece 18 provided on the protective film 17 as shown in Figure 12.

As shown in FIG. 13(B), when a reinforcing piece 18 is provided, even if a bending force is applied from the terminal member 21 to the flat conductor cable 10, the radius of curvature of the flat conductor cable becomes larger than in the case shown in FIG. 13(A), dispersing the stress concentration applied to the flat conductor cable and suppressing deterioration of the flat conductor cable.

Figure 14 is a perspective view showing a flat conductor cable 10 with a modified reinforcing piece. The reinforcing piece 18 shown in Figure 14 has a mountain shape so that the widthwise center portion narrows toward the protruding end, and the strength of the widthwise center portion of the flat conductor cable 10 is increased.

As described above, the flat conductor cable 10 uses a thin film for insulation, and has the advantage of being able to reduce the cross-sectional area compared to a circular cross-sectional electric wire. In electronic devices that are routed using electric wires with a circular cross-sectional area, such as industrial equipment and facilities, the use of a flat conductor cable makes it possible to increase the number of electrical connections by adding functions to the equipment, without expanding the space, even if the space in the electric wire routed section is already occupied by electric wires. In such a case, if the overall width of the flat conductor cable is significantly expanded, it becomes impossible to arrange the cable within a specified space. In contrast, the use of the above-mentioned flat conductor cable 10 makes it possible to reduce the overall width. This provides the advantage of being able to increase the functionality of the equipment without expanding the routed space or changing the external or internal structure of the electronic device.

For example, in communication devices, the individual units of electronic equipment continue to grow in size due to increased communication speeds, and the space between units is becoming narrower due to increased functionality. Under these circumstances, application of the small flat conductor cable 10 of the present invention can contribute to adding functionality by increasing the number of connections between units. Furthermore, it can also be used to connect in-vehicle devices, which are becoming increasingly electronic, and can contribute to structural design that is considerate of the global environment as well as improving fuel efficiency through weight reduction.

The invention made by the inventor has been specifically described above based on the embodiments, but the embodiments disclosed in this specification are illustrative in all respects and are not limited to the disclosed technology. In other words, the technical scope of the present invention should not be interpreted restrictively based on the explanation in the above embodiments, but should be interpreted strictly according to the description of the claims, and includes technologies equivalent to the technologies described in the claims and all modifications that do not deviate from the gist of the claims.

For example, the flat conductor cable 10 shown in the figure is applied as an FFC, but is not limited to this, and the flat conductor cable of the present invention can also be applied as an FPC, i.e., a flexible printed circuit board.

The present invention can be used as wiring material for electrical wiring in electronic devices, automobiles, etc.

REFERENCE SIGNS LIST 10 flat conductor cable 11 conductor wire 12 insulating coating 13 end face 14 protruding end 15 slit 17 protective film 18 reinforcing piece 21 terminal member 24 shielding protrusion 25 first connection portion 26 second connection portion 27 hinge portion 28 engagement claw 29 engagement groove 31 terminal body 32 connector terminal 33 connection terminal 34 first screw member 35 second screw member 36 shielding wall

Claims (3)

A connection terminal structure for a flat conductor cable including a plurality of conductor wires and an insulating coating covering the conductor wires,
a protruding end portion at an end of the flat conductor cable, the protruding end portion being formed by protruding from an end face of the insulating coating such that a plurality of conductor wires are parallel to each other;
a slit formed in an end portion of the insulating coating between adjacent ones of the conductor wires;
a terminal member made of an insulating material and provided at an end of the flat conductor cable, the terminal member having a function as a connector;
the terminal member includes a first connection portion disposed on one side of the flat conductor cable, and a second connection portion connected to the first connection portion via a hinge portion so as to be freely opened and closed and disposed on the other side of the flat conductor cable, and an exposure portion is provided on one of the first connection portion and the second connection portion to expose a protruding end portion of the conductor wire;
A connection terminal structure for a flat conductor cable, characterized in that the terminal member is provided with a shielding protrusion that is inserted into the slit and a location over the entire length between the exposed protruding ends of the conductor wire. 2. The flat conductor cable connection terminal structure according to claim 1, wherein a protective film is provided on at least one of both surfaces of the end portion of said insulating coating . 3. A connection terminal structure for a flat conductor cable as described in claim 2, characterized in that a reinforcing piece protruding toward the longitudinal center of the flat conductor cable is provided on the protective film, so that when the flat conductor cable is bent, stress concentration on the flat conductor cable is dispersed to the reinforcing piece .

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