JP5144955B2 - Flexible flat cable - Google Patents

Description

  The present invention relates to a flexible flat cable.

  A flexible flat cable (hereinafter also referred to as FFC) is a tape-shaped insulator having flexibility, in which a linear conductor having a flat cross section is embedded. FFC is thin and excellent in flexibility, and is used as various wiring materials such as roofs, doors, floors, and instrument panels of automobiles.

  Conventionally, an FFC has been manufactured by a thermal laminating method in which a conductor is sandwiched between two adhesive layers of an insulating film having a thermal adhesive layer on one side, and the insulating films are thermally bonded through a heating roller. As the FFC insulating film, a polyester film such as a polyethylene terephthalate film has been used.

  However, the FFC manufacturing method using the thermal laminating method involves heating and melting the adhesive layer, and it takes time to bond, so that there is a problem that the productivity of FFC is low and the cost is high. Therefore, it is known to reduce the manufacturing cost of FFC by manufacturing FFC by an extrusion method in which an insulating resin is extrusion coated around a linear conductor using an extruder (see, for example, Patent Document 1). .

Japanese Patent No. 3700861

  By the way, FFC by the extrusion method currently mass-produced has used soft resins, such as a polyurethane elastomer and a polyvinyl chloride resin, as a material of an insulator. The FFC by the extrusion method using these insulators has a problem that it is easy to be wound compared with the FFC by the heat laminating method. For example, when an FFC is routed on the body of an automobile, there are the following problems if it is wrapped. The FFC is bundled with a predetermined length, and is packed with rubber and packed as an FFC harness. Then, remove the rubber that tied the FFC harness, spread the harness and route it to the body. FFC by the heat laminating method is difficult to curl and spreads naturally throughout the body as soon as the rubber is removed. However, in the case of extruded FFC, if there is wrapping at the time of packing, it will not spread naturally when the rubber is removed. If the FFC does not spread immediately, it is necessary to extend the harness by hand and the routing workability will be reduced.

  The problem to be solved by the present invention is to solve the above-mentioned problems, and even when the cables are bundled, it is difficult to wind them up, and when the cables are spread out from the bundled state, they can spread immediately. An object of the present invention is to provide an FFC with excellent routing workability.

  In order to solve the above problems, the flexible flat cable of the present invention is a flexible flat cable in which a plurality of rectangular conductors arranged in parallel inside a tape-like insulator made of an insulating resin formed by extrusion molding are embedded. A ratio of the case where a flexible flat cable is wound in triplicate to form an annular shape with a diameter of 50 mm, and a load W [N] is applied from the outside so that the annular shape is crushed and deformation of δ [mm] is caused ( When W / δ) is a repulsive force coefficient K [N / mm], the gist is that the repulsive force coefficient K is 0.04 to 0.75 [N / mm].

  The flexible flat cable can be formed to have a thickness of 0.15 to 0.6 mm and a width of 3 to 50 mm. The rectangular conductor can be formed with a thickness of 0.1 to 0.2 mm and a width of 1 to 3 mm.

  In the flexible flat cable, the flat conductor is preferably tough pitch annealed copper, and the insulating resin is preferably made of a modified polyphenylene ether.

  The measuring method of the repulsive force coefficient K of the flexible flat cable in the present invention is as follows. Fig.1 (a) is explanatory drawing which shows the test piece of the flexible flat cable used for the measurement of a repulsive force coefficient, The same figure (b) is BB sectional drawing of (a). As shown in FIGS. 1A and 1B, the flexible flat cable 1 is wound three times to form a test piece 10 having an annular shape with a diameter of 50 mm. The test piece 10 is fixed by winding the adhesive tape 2 around the overlapping portion of the flexible flat cable 1 so that the overlapping portions of the flexible flat cable 1 are not unraveled, so that the portions at the beginning and end of winding overlap 10 mm. .

  2 (a) and 2 (b) are explanatory views showing a method for measuring the repulsive force coefficient K, (a) showing a state before the annular body of the test piece is deformed, and (b) showing a deformation of the test piece. Indicates the state of being made. In the test, the tensile tester 20 is set in the indentation load measurement mode, the test piece 10 is arranged between the load cell 21 and the jig 22 as shown in FIG. 2A, and fixed to the lower jig with the double-sided tape 23. To do. Next, as shown in FIG. 2B, the upper load cell 21 is displaced downward to 40 mm so as to crush the ring of the test piece 10. The pushing speed at this time is 50 mm / min. When the test piece 10 is pushed by the load cell 21, it becomes a flat shape having a height of 10 mm. At this time, in the load cell 21, the repulsive force that the ring of the test piece 10 to be crushed returns to its original state by spring elasticity is measured as a load. When the displacement [mm] and the load [N] applied to the load cell 21 are measured, a graph showing the relationship between the displacement and the load is obtained.

  FIG. 3 is a graph showing the relationship between indentation displacement and load obtained by the measurement method. As shown in FIG. 3, a graph composed of the indentation displacement-load curve S is obtained by the above measuring method. The slope of this curve S is defined as a repulsive force coefficient K (N / mm). That is, the slope of this graph represents the ratio W / δ when the load measured by the load cell is W (N) and the indentation displacement that crushes the 50φ ring to a height of 10 mm is the deformation amount δ (mm). Is.

  It can be said that the repulsive force coefficient K according to the present invention indicates the spring elasticity of the flexible flat cable. The repulsive force coefficient K is an index of difficulty in winding and routing. That is, the flexible flat cable of the present invention is formed in an annular shape having a diameter of 50 mm by wrapping in a triple manner so that the deformation amount becomes δ [mm] by applying a load W [N] from the outside so that the annular shape is crushed. The cable is bundled in comparison with a flexible flat cable by a conventional extrusion method because the repulsive force coefficient K is 0.04 to 0.75 [N / mm]. It is difficult to wrap around, and when it is unfolded from a bundled state, it can spread immediately, and the wiring workability is excellent.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 4 is a longitudinal sectional view in the width direction showing an example of the flexible flat cable of the present invention. As shown in FIG. 4, the flexible flat cable 1 (hereinafter also referred to as FFC) includes a plurality of rectangular conductors arranged in parallel inside a tape-like insulator 12 made of an insulating resin formed by extrusion molding. A conductor 11 composed of 11a, 11b, and 11c is embedded. The periphery of the conductor 11 is in contact with the insulator 12. The FFC 1 shown in FIG. 4 has three conductors 11a, 11b, and 11c arranged in parallel at a predetermined interval. The contact surface of the conductor 11 and the insulator 12 is in a close contact state, but may be in a state in which the conductor 11 and the insulator 12 are in contact with each other. Also good.

  The FFC 1 shown in FIG. 4 has a rectangular cross section, and is formed as a flat surface with no irregularities on the front and back surfaces. The corners of the FFC 1 are not particularly chamfered. In the FFC 1, there is no distinction between the front side and the back side, but for the sake of convenience, the upper side in FIG. 4 is the front side and the lower side is the back side.

  FIG. 5 is a longitudinal sectional view in the width direction showing another example of the FFC of the present invention. As shown in FIG. 5, the FFC 1 may have a shape in which a corner portion R is chamfered. Further, as shown in the figure, the FFC 1 may be provided with a groove G having a V-shaped cross section extending in the longitudinal direction in a portion between the conductors 11 on the front surface and the back surface.

  As described above, the FFC 1 of the present invention is formed by winding the FFC in triplicate to form an annular shape with a diameter of 50 mm, and applying a load W [N] from the outside so that the annular shape is crushed, the deformation amount is δ [mm]. In this case, the repulsive force coefficient K is 0.04 to 0.75 [N / mm]. When the repulsive force coefficient K of FFC1 is out of the above range and is less than 0.04 [N / mm], the repulsive force is too small to obtain sufficient routing. On the other hand, if the repulsive force coefficient K exceeds 0.75 [N / mm], it will be difficult to wind, but the repulsive force will be too large, and the routing will be reduced. The repulsive force coefficient K is more preferably 0.05 to 0.15 [N / mm] because it can surely prevent winding and a good routing property can be obtained with certainty.

  In order to set the repulsive force coefficient K in the FFC 1 within the above range, a desired combination of the dimensions (width, thickness), material, material of the insulator 12, the structure of the insulator 12, and the like of the conductor 11 in the FFC 1 can be obtained. An FFC 1 having a repulsive force coefficient K can be configured. The structure of the insulator 12 includes, for example, the presence or absence of uneven shapes on the surface of the insulator 12, the arrangement of the conductor 11, and the like. For example, as shown in FIGS. 4 and 5, in the FFC 1, the repulsive force coefficient K of the FFC 1 can be changed depending on the presence / absence of chamfering of the corner portion R, the presence / absence of the groove G on the front and back surfaces, and the like.

  The preferred dimensions of the FFC 1 are 3 to 50 mm in width and 0.15 to 0.6 mm in thickness. If the dimension of FFC1 is the said range, FFC1 which has the repulsive force coefficient K of the said specific range will be obtained easily. The FFC 1 having the above size range can be optimally used for wiring a general automobile body.

  4 and 5, the flat conductor 11 of the FFC 1 is formed in a rectangular shape whose thickness is smaller than the width in the cross-sectional shape of the FFC 1 in the width direction. The flat conductor 11 has a flat cross-sectional shape. Those having the following are preferred. The FFC 1 is embedded in the insulator 12 at the same depth in the thickness direction inside the insulator 12. The flat conductor 11 is made of conductive wire such as copper, copper alloy, aluminum, aluminum alloy, or copper plated with tin. Tough pitch annealed copper is one of the preferred materials for flat conductors because of its good electrical conductivity, cost, and flexibility. The rectangular conductor 11 preferably has a flat cross-sectional shape. The preferred dimensions of the flat conductor 11 are, for example, a thickness of 0.1 to 0.2 mm and a width of 1 to 3 mm.

  The insulator 12 of the FFC 1 is formed by an extrusion method. In the extrusion method, the resin of the insulator 12 is obtained by extrusion coating with respect to the plurality of linear conductors 11a to 11c using an extruder. The extrusion method has higher FFC productivity than the FFC manufacturing method using the thermal laminating method, and can manufacture the FFC at a low cost. As the extrusion method, a known FFC production method can be used.

  As the material of the insulator 12, the insulator 12 can be formed by extrusion molding, and an insulating resin that can be formed so as to be in the range of the repulsive force coefficient K in the case of FFC1 is used. Preferred materials for the insulating resin include modified polyphenylene ether, hydrogenated styrene thermoplastic elastomer, modified hydrogenated styrene thermoplastic elastomer, polypropylene, polyetherimide, and the like. These may be a single type or a mixture of two or more types. The resin is preferable because it is easy to balance flame retardancy and insulation. In particular, the insulator 12 is more preferably used because the modified polyphenylene ether is easy to balance the flame retardancy and the insulating property, and the cost is low and the repulsive force coefficient is easily within a desired range.

  To the insulator 12, additives such as a flame retardant, a molding aid, an inorganic filler, an ultraviolet absorber, and a stabilizer may be added to the resin.

Examples of the present invention and comparative examples are shown below.
Example 1
80 parts (hereinafter, all parts by mass) of modified polyphenylene ether (modified PPE) as an insulating resin in a state in which three cores are arranged in parallel at a pitch of 2.5 mm and a tough pitch annealed copper having a thickness of 0.1 mm and a width of 1.5 mm; An FFC was produced by using a blended composition (see Table 1) comprising 20 parts of a hydrogenated styrene-based thermoplastic elastomer and extruding it to a thickness of 200 μm. The obtained FFC was subjected to tests for repulsive force coefficient K, tackiness, and routing followability, and was subjected to comprehensive evaluation. The results are shown in Table 2.

Insulator composition

  The test methods for the tackiness and the routing followability are as follows.

[Hiddenness]
6 (a) and 6 (b) are explanatory diagrams of a method for measuring the tackiness. As shown in FIG. 6A, the FFC 1 is wound once to form a ring, and the end is fixed with a clip 24. In this state, it is allowed to stand at 23 ° C. for 168 hours. Next, as shown in FIG. 2B, the distance X between the end portions of the FFC 1 is measured in a state where the clip 24 at the end portion is removed and opened. The one where the distance X between the end portions is larger means that the FFC is less likely to become habit, and it can be said that the habitability is good. In the evaluation of the biting property, the case where the distance X between the end portions is 40 mm or more was evaluated as ◯, and the case where the distance X was less than 40 mm was evaluated as ×.

[Routing tracking]
7A to 7C are explanatory diagrams of a method for measuring the routing followability. As shown in FIG. 7A, the FFC 1 is bent 180 degrees. Then, as shown in FIG. 5B, the bent portion is pressed with a weight 24 having a load of 5 kgf. FIG. 3C is an enlarged view of a bent portion. As shown in FIG. 5C, the distance Y between the FFCs of the bent portion of the FFC 1 is measured while being pressed by the weight 24. It can be said that when the distance Y between the folded FFCs 1 is smaller, the FFC 10 has better bendability and followability to the automobile body when routing, and the routing ability is excellent. In the evaluation of the routing property, the case where the distance Y between the folded FFCs 1 was 3.0 mm or less was evaluated as ◯, and the case where the distance Y exceeded 3.0 mm was evaluated as x.

Examples 2-4, Comparative Examples 1-3
An FFC was produced in the same manner as in Example 1 except that the insulating resin having the composition shown in Table 1 was used and the conductor size, pitch, insulator thickness, and number of cores were as shown in Table 2. did. The obtained FFC was subjected to tests for repulsive force coefficient K, tackiness, and routing followability, and was subjected to comprehensive evaluation. The results are shown in Table 2.

Reference example 1
For reference, an FFC was manufactured by sandwiching a conductor shown in Table 2 between a film in which a hot melt adhesive having a thickness of 40 μm was applied to a polyethylene terephthalate having a thickness of 50 μm, and a conductor shown in Table 2. The obtained FFC was tested for the repulsive force coefficient K, the tackiness, and the routing followability. The results are shown in Table 2.

(A) is explanatory drawing which shows the test piece of the flexible flat cable used for the measurement of a repulsive force coefficient, (b) is BB sectional drawing of (a). It is explanatory drawing which shows the measuring method of the repulsive force coefficient K, (a) shows the state before the deformation | transformation of the annular body of a test piece, (b) shows the state which has deform | transformed the test piece. It is a graph which shows the relationship between the indentation displacement and load which are obtained by the measuring method of FIG. It is a longitudinal cross-sectional view of the width direction which shows an example of this invention flexible flat cable. It is a longitudinal cross-sectional view of the width direction which shows the other example of this invention flexible flat cable. (A), (b) is explanatory drawing of the measuring method of a biting property. (A)-(c) is explanatory drawing of the measuring method of routing followability.

Explanation of symbols

1 Flexible flat cable (FFC)
10 FFC specimen 11 Flat conductor 12 Insulator 20 Tensile tester 21 Load cell 22 Jig

Claims (5)

  In a flexible flat cable in which a plurality of flat conductors arranged in parallel are embedded in a tape-like insulator made of an insulating resin formed by extrusion molding, the flexible flat cable is wound in triplicate to form an annular shape having a diameter of 50 mm The ratio (W / δ) in the case of forming and deforming δ [mm] by applying a load W [N] from the outside so that the ring is crushed is expressed as a repulsive force coefficient K [N / mm]. In this case, the flexible flat cable has a repulsive force coefficient K of 0.04 to 0.75 [N / mm].   The flexible flat cable according to claim 1, wherein the flexible flat cable has a thickness of 0.15 to 0.6 mm and a width of 3 to 50 mm.   The flexible flat cable according to claim 1 or 2, wherein the flat conductor has a thickness of 0.1 to 0.2 mm and a width of 1 to 3 mm.   The flexible flat cable according to claim 1, wherein the flat conductor is tough pitch annealed copper.   The flexible flat cable according to any one of claims 1 to 4, wherein the insulating resin is a modified polyphenylene ether.

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