JP2013258104A - Cable with oil resistant and flex resistant sheath, cable harness using the same, and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cable with an oil resistant and flex resistant sheath which improves the oil resistance and the flex resistance of the cable and applies a resin having a rated temperature of 200°C or lower to an insulator.SOLUTION: A cable with a resistant and flex resistant sheath includes: multiple electric wires 2, each of which has a conductor and an insulator coating an outer periphery of the conductor and the conductor; a pressing tape 3 wound around the outer peripheries of the twisted electric wires 2; and a sheath 5 coating an outer periphery of the pressing tape 3. The insulator has a rated temperature of 200°C or lower, and the sheath 5 is a composite of a fluorine resin and fluororubber.

Description

  The present invention relates to a cable with an oil-resistant / bending-resistant sheath, and in particular, an oil / bending-resistant cable suitable for control signal transmission and power supply in a movable part of a movable device such as an industrial robot, an automatic machine tool, and an electric actuator. The present invention relates to a cable with a sheath, a cable harness using the cable, and a manufacturing method of a cable with an oil-resistant / flexible sheath.

  Bending-resistant cables are used for control signal transmission and power supply for movable parts of movable devices such as work robots, automatic machine tools, and electric actuators.

  As a bending-resistant cable used in these devices, a bending-resistant cable with a PVC (polyvinyl chloride) or PU (polyurethane) sheath is generally used.

  As shown in FIG. 4, in these conventional bending-resistant cables 21, seven or more stranded conductors are irradiated with crosslinked PVC, irradiated crosslinked polyethylene, irradiated crosslinked polyethylene or polypropylene, expanded polypropylene, ETFE (tetrafluoroethylene / ethylene). Copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer (4.6 fluoro)), PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) 2 In general, a plurality of press tapes 3 and a collective shield 4 are provided after being twisted at a constant pitch, and a soft PVC sheath 22 is coated thereon. In addition, as shown in FIG. 5, some of the bending-resistant cables 31 for supplying power have a structure without a collective shield.

  By the way, with recent diversification of equipment, various types of oil are used around the moving parts of the equipment, and cables are required to have high oil resistance that can withstand such various oils for a long time. ing.

JP 2009-224048 A

  However, since various components such as a plasticizer and a stabilizer are used in the PVC sheath 22, the oil component easily penetrates, and when immersed for a long time, the PVC sheath 22 is cured by the oil component, As a result of the swelling, the mechanical properties (elongation and tensile strength) of the bending resistant cables 21 and 31 coated with the PVC sheath 22 deteriorate, and the bending resistance is remarkably impaired.

  As a method of increasing the oil resistance of the PVC sheath 22, there is a method of reducing the plasticizer, but if the plasticizer is greatly reduced, the softness of the PVC sheath 22 is impaired and hardened, making extrusion difficult, and bending resistance of the cable. Sex will also decline.

  There is also a method of using relatively soft fluororesins FEP and PFA with excellent oil resistance instead of the PVC sheath 22, but since it is harder and less elastic than PVC, scratches and cracks are likely to occur during handling, and bending resistance It is not suitable for the sheath of the cable 21.

  In addition, there is a method of using fluorine rubber with excellent bending resistance, Fullon Afras (registered trademark) manufactured by Asahi Glass Co., Ltd., but it requires a vulcanization process at a temperature of about 200 ° C. for several minutes. Irradiated cross-linked PVC, irradiated cross-linked polyethylene, irradiated cross-linked polyethylene, polypropylene, expanded polypropylene, ETFE, and other materials coated on the body are melted during the vulcanization process, impairing the insulation performance of the cable. (For example, the rated temperature is 80 to 105 ° C. for irradiated crosslinked PVC, 80 to 105 ° C. for irradiated crosslinked PE, and 150 ° C. for ETFE).

  Therefore, FEP (rated temperature: 200 ° C.) and PFA (rated temperature: 250 ° C.) with a rated temperature of 200 ° C. or higher that can sufficiently withstand the vulcanization temperature of 200 ° C. are applied to the insulator, and the sheath has excellent bending resistance. There is also a method to coat fluororubber full-on-aflas, but the material of the insulator is limited to two kinds of materials such as FEP and PFA, or moisture attached to the cable interposition 6 or insulating material in the vulcanization process volatilizes, Air bulging in the fluororubber sheath is likely to occur, and a thickness of 0.8 mm or more is required as a countermeasure. The cable satisfies various electrical characteristics requirements, light weight and diameter reduction requirements, and bending characteristics requirements. Design becomes difficult and the degree of freedom in design is impaired.

  On the other hand, in equipment with moving parts, such as industrial robots, automatic machine tools, and electric actuators, as the number of functions and miniaturization progresses, signal transmission for control of moving parts and control cables for power supply are highly oil resistant.・ Although high bending resistance is required, diameter reduction is also required.

  In order to meet these requirements, a cable with a sheath that can be coated on insulated wires of various insulating materials, has excellent oil resistance and bending resistance, and can be extruded with a thin wall thickness of 0.8 mm or less is required. is there.

  Accordingly, an object of the present invention is to provide an oil-resistant / flexible sheath that solves the above problems, improves the oil resistance and flex resistance of the cable, and can apply a resin having a rated temperature of 200 ° C. or less to the insulator. An object of the present invention is to provide a cable, a cable harness using the cable, and a method for manufacturing a cable with an oil-resistant / flexible sheath.

  In order to solve the above problems, the present invention provides a conductor and a plurality of electric wires having an insulator coated on the outer periphery of the conductor, a pressing tape wound around the outer periphery of the plurality of electric wires twisted together, A sheath covering an outer periphery, wherein the insulator has a rated temperature of 200 ° C. or less, and the sheath is a composite of fluororesin and fluororubber.

  The thickness of the sheath is preferably 0.1 to 0.2 times the cable outer diameter.

  The terminal-attached cable harness includes the cable with the oil-resistant / bending-resistant sheath and the connector connected to the terminal portion of the cable with the oil-resistant / bending-resistant sheath.

  Furthermore, the manufacturing method of the cable with the oil-resistant / bending-resistant sheath was twisted together with the first step of twisting a plurality of electric wires composed of a conductor and an insulator with a rated temperature of 200 ° C. or less coated on the outer periphery of the conductor. A second step of winding a pressing tape around the outer circumferences of the plurality of electric wires; and a third step of covering the outer periphery of the pressing tape with a dynamically cross-linked sheath made of a composite of fluororesin and fluororubber. Is.

  According to the present invention, the oil resistance and bending resistance of the cable can be improved, and a resin having a rated temperature of 200 ° C. or less can be applied to the insulator.

It is sectional drawing of the cable with an oil-resistant and bending-resistant sheath which concerns on one embodiment of this invention. It is sectional drawing of the cable with an oil-proof and bending-proof sheath which shows other embodiment. It is a front view of the cable harness using the cable with an oil-proof and bending-proof sheath. It is sectional drawing of the conventional cable with an oil-resistant and bending-resistant sheath. It is sectional drawing of the conventional cable with an oil-resistant and bending-resistant sheath.

  An oil-resistant / flexible-resistant sheathed cable according to the present invention will be described with reference to the accompanying drawings. The oil-resistant / flexible sheathed cable shown in FIG. 1 is for control signal transmission.

  As shown in FIG. 1, a cable 1 with an oil-resistant / flexible sheath includes a plurality of electric wires 2 twisted and assembled at a constant pitch, and a pressing tape 3 wound around the outer periphery of the plurality of electric wires 2 twisted together, A sheath 5 is provided on the outer periphery of the pressing tape 3 and is covered with a collective shield 4.

  The electric wire 2 is a signal twisted wire core, a shielded wire core, or a coaxial wire core. The electric wire 2 has a conductor (not shown) and an insulator (not shown) coated on the outer periphery of the conductor. A conductor consists of 7 or more strand wire conductors excellent in flexibility. For the insulator, a resin having a rated temperature of 200 ° C. or less can be used, and it is made of, for example, irradiation-crosslinked PVC, irradiation-crosslinked polyethylene, irradiation-crosslinked foamed polyethylene or polypropylene, foamed polypropylene, ETFE, FEP, PFA or the like. An interstitial 6 is provided between the electric wires 2.

  The pressing tape 3 is made of a slippery paper tape, PET tape, nylon tape, or ETFE tape.

  The collective shield 4 is made of a horizontal winding or a braided shield made of copper wire or copper foil yarn.

  The sheath 5 is made of a fluororubber resin that is excellent in bending resistance and can be extruded by a thin wall, that is, a composite of fluororesin and fluororubber. Such a composite can be dynamically vulcanized by heat during extrusion. Specifically, the sheath 5 is made of Daiel Fluoro TPV (Thermoplastic Vulcanizates) (registered trademark) manufactured by Daikin Industries.

  The fluororesin constituting the composite is an ETFE resin which is a non-perfluoro resin. The fluororubber is made of a vinylidene fluoride / hexafluoropropylene copolymer or a vinylidene fluoride / hexafluoropropylene / tetrafluoroethylene copolymer. The mass ratio of the fluororesin and fluororubber is 75/25 to 25/75. The fluororubber is formed into particles and is uniformly finely dispersed in the fluororesin matrix.

  The sheath 5 has a specific gravity of 1.87, a melt flow rate (MFR) of 3 to 20 (g / 10 min), a melting point of about 220 ° C., and an elongation of about 300 to 400%. In addition, the sheath 5 has characteristics similar to ETFE resin that can be extruded at a thin rate of about 0.2 mm at a take-up speed of 5 to 50 m / min, and has a hardness (Shore-A) of about 90 like rubber. is there.

  In the case of manufacturing such an oil-resistant / flexible-resistant sheathed cable 1, after the first step of twisting a plurality of electric wires 2 made of a conductor and an insulator having a rated temperature of 200 ° C. or less coated on the outer periphery of the conductor, The second step of winding the pressing tape 3 around the outer circumferences of the plurality of electric wires 2 twisted in the step is performed, and the outer periphery of the pressing tape 3 is dynamically cross-linked (dynamically added with a composite of fluororesin and fluororubber). A third step of covering the sheath 5 that has been sulfurized is performed. The sheath 5 is coated using an extruder (not shown), and dynamic crosslinking is performed with heat during extrusion. Since a vulcanization process is not required, it is possible to prevent moisture attached to the interposition 6 and the like from volatilizing and air bulging from occurring in the sheath 5, and the sheath 5 can be made thin.

  Thus, since the insulator of the electric wire 2 has a rated temperature of 200 ° C. or less and the sheath 5 is a composite of fluororesin and fluororubber, the cable has high oil resistance, high bending resistance, light weight and a small diameter. realizable. And since the composite of fluororesin and fluororubber has a rated temperature of 150 ° C. like ETFE, higher heat resistance can be obtained than a conventional PVC sheath having a maximum heat resistance of 105 ° C.

  Further, since the thickness of the sheath 5 is set to be 0.1 times or more and 0.2 times or less of the cable outer diameter, the cable 1 with the oil / bending resistant sheath can be stably manufactured. If the sheath thickness is less than 0.1 times the outer diameter of the cable, it will be too thin, and it will be easy for twisted lines to occur on the sheath surface during extrusion molding. There is a possibility that a sheath crack may occur at the location. On the other hand, if the sheath thickness is 0.2 times or more of the cable outer diameter, the heat of the fluororubber resin melted at the time of forming the sheath is less likely to be dissipated and easily transmitted to the insulator of each electric wire 2. There is a possibility that the two insulators are fused with each other and the bending resistance of the cable is deteriorated.

  In addition, although the oil-resistant / flexible sheathed cable 1 for signal transmission for control has been described, the present invention is not limited to this. As shown in FIG. 2, the oil-resistant / flexible-resistant sheathed cable 11 may be a power supply cable having a structure without a collective shield. In this case, the electric wire 12 may be made of a power insulating wire. The presser tape 3, the collective shield 4, the sheath 5 and the interposition 6 in FIG.

  As shown in FIG. 3, the cable harness 13 with terminal includes a cable 1 (11) with an oil-resistant / bend-resistant sheath and a connector 14 connected to the terminal portion of the cable 1 (11) with an oil-resistant / bend-resistant sheath. It is good to have it. The connector 14 may be connected to the terminal portions at both ends of the cable 1 (11) with an oil-resistant / flexible sheath.

  Next, Table 1 shows the results of the oil resistance test and the bending resistance test performed on Examples 1 and 2 and Comparative Examples 1 and 2.

  The sheath material of the cables of Examples 1 and 2 is Daiel Fluoro TPV, and the sheath material of the cables of Comparative Examples 1 and 2 is soft PVC.

  In Examples 1 and 2 and Comparative Examples 1 and 2, the conductor size of the plurality of electric wires of the cable is 26 AWG (American Wire Gauge), and the number of stranded wire conductors constituting the electric wire is 30. The diameter is 0.08 mm. Moreover, the thickness of the pressing tape is 0.05 mm, and the thickness of the sheath is 0.7 mm.

  Moreover, in Example 1 and Comparative Example 1, the insulator of the multiple electric wires of the cable is irradiated PVC, the twisted outer diameter of the multiple electric wires is 3.1 mm, the outer diameter of the cable is 4.6 mm, and the sheath Is approximately 0.15 times the cable outer diameter. In Example 2 and Comparative Example 2, the insulator of the multiple electric wires of the cable is ETFE, the twisted outer diameter of the multiple electric wires is 2.8 mm, the outer diameter of the cable is 4.3 mm, and the thickness of the sheath Is about 0.16 times the cable outer diameter.

  In the oil resistance test, the sheath portion of the cable was immersed in a water-soluble / water-insoluble cutting oil at 40 ° C. for 5000 hours, taken out every 500 hours, measured for discoloration of the sheath, elongation / tensile strength, and compared with the initial value. . When the elongation and tensile strength were reduced by 20% compared to the initial value, it was determined as defective.

  In the bending resistance test, a load of 500 g was applied with a bending R (in this example, 20 mm) of about 4 times the outer diameter of the cable, and repeated bending of ± 90 degrees was performed. When the conductor resistance value of the plurality of electric wires increased by 20%, it was determined that the wire was disconnected.

  In Examples 1 and 2, discoloration of the sheath and reduction in elongation / tensile strength were not observed compared to the initial stage even after 5000 hours had elapsed, and the oil resistance was good. And each bending resistance was also favorable compared with the comparative examples 1 and 2 which are the same structures except the material of a sheath.

  In Comparative Examples 1 and 2, the bending resistance is good, but since the sheath dipped in the water-insoluble cutting oil was cured after 500 hours, the elongation decreased by 20% or more from the initial stage, and the oil resistance was It was bad.

1 Oil-resistant / flexible sheathed cable 2 Electric wire 3 Holding tape 4 Batch shield 5 Sheath

Claims (4)

A plurality of electric wires having a conductor and an insulator coated on the outer periphery of the conductor, a pressing tape wound around the outer periphery of the plurality of electric wires twisted together, and a sheath covered on the outer periphery of the pressing tape,
The insulator has a rated temperature of 200 ° C. or less,
A cable with an oil-resistant / bending-resistant sheath, wherein the sheath is a composite of fluororesin and fluororubber.   The cable with an oil-resistant / flexible sheath according to claim 1, wherein the thickness of the sheath is 0.1 to 0.2 times the outer diameter of the cable.   A cable harness with a terminal, comprising: the cable with an oil-resistant / bending-resistant sheath according to claim 1; and a connector connected to a terminal portion of the cable with the oil-resistant / bending-resistant sheath.   A first step of twisting a plurality of electric wires made of a conductor and an insulator having a rated temperature of 200 ° C. or less coated on the outer periphery of the conductor, and a second step of winding a pressing tape around the outer periphery of the plurality of twisted electric wires And a third step of covering the outer periphery of the pressing tape with a dynamically cross-linked sheath made of a composite of fluororesin and fluororubber. .