JPH0433085B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to the flexibility of cables in which a braided conductor layer is provided around the outer periphery of the cable core, such as coaxial cables and shielded multi-core cables.
This relates to improvements in bending life, etc.

[Conventional technology]

2. Description of the Related Art In recent years, various electronic devices having moving parts, including automated devices such as industrial robots, have been developed, and various cables have been used as inter-device or intra-device cables. Cables used for such purposes may send erroneous signals to the equipment if they are affected by external noise, which may cause the equipment to malfunction and cause serious accidents. Since there is a risk that electromagnetic waves may be emitted from the cable itself to the outside and cause similar results, it is recommended to braid or spirally wind a metal wire such as annealed copper wire around the outer circumference of the cable core, or spirally wind or wind a metal foil tape around the outer periphery of the cable core. It is essential to provide a shield layer formed by vertically attaching or the like.

By the way, the cables used to connect the movable parts and the fixed parts in these devices are subject to repeated deformations such as rotation, expansion and contraction, and bending as the movable parts move. In addition, it is necessary to be able to respond to such deformation such as bending in a soft and flexible manner. Therefore, for cables for this type of use, among the various shield structures mentioned above, multiple metal wires are used in order to improve the flexibility of the finished cable and the stability of its electrical characteristics. A braided shield, which is formed by intersecting and braiding the cable core, is most commonly used.

Particularly in recent years, the performance of robots has improved and their operating speeds have become faster and faster, and the movements of moving parts have also become more complex.In addition, various electronic devices have become smaller and lighter and faster. As technology progresses and rapid bending is required repeatedly within a limited space, the cables used for these moving parts must have greater flexibility, shield structure stability, and durability than ever before. Flexibility is strongly required.

In order to solve these problems, Japanese Utility Model Application Publication No. 58-64012 discloses that an unfired fluororesin tape is wrapped around the outer periphery of a cable core made of twisted insulated wire cores as a pressing tape. A shielded braided multi-core cable is disclosed which has a braided cable layer and a jacket sequentially applied to the outer periphery of the cable. Such multi-core cables prevent slippage between the cable core and the braided shield layer during bending due to the low-friction fluororesin tape winding layer provided between the braided shield layer and the cable core. , aiming to improve flexibility.

[Problem that the invention seeks to solve]

However, in the above invention, although flexibility is improved to some extent by making it easier to slide between the cable core and the braided shield layer,
Since the jacket on top of the braided shield layer is extruded and coated as it is, close contact between the two is unavoidable.Therefore, when the cable is bent, there is no slippage between the two and they are displaced as one with respect to the cable core. This resulted in suppressing the flexibility of the shield layer. Furthermore, since the braided shield layer is difficult to deform, stress is locally concentrated in the braided shield layer, which may cause disconnection of the braided strands.

The object of the present invention is to solve the problems of the prior art and to provide a cable with a braided conductor that has excellent flexibility and bending resistance, and is also highly stable in terms of electrical characteristics.

[Means for solving problems]

The present invention has been made in view of the problems of the prior art described above, and therefore, according to the present invention, at least one insulated wire core and a braided conductor layer formed by braiding metal wires provided on the outer periphery of the wire core are provided. In the cable with a braided conductor layer, a composite plating layer containing a fixed lubricant is provided on the outer periphery of the metal wire.

In this configuration, a composite plating layer containing one or more solid lubricants such as fluororesin, silicone resin, graphite, graphite fluoride, molybdenum disulfide, tungsten disulfide, alumina, etc. is provided around the outer periphery of the metal wire. If, for example, they are braided around the outer periphery of a cable core consisting of a plurality of insulated wire cores to form a braided conductor layer, a shielded multi-core cable with excellent flexibility and bending resistance can be obtained.

In addition, when a single insulated wire core is used as the cable core, and a metal wire with the above-mentioned composite plating layer is braided on the outer periphery and a braided conductor layer is provided coaxially, the cable may be exposed to mechanical vibrations. A low-noise coaxial cable that generates extremely little static electricity noise when bent can be obtained.

[Effect]

According to the present invention, as described above, a metal wire is provided with a composite plating layer on the outer periphery of which a solid lubricant having self-lubricating properties such as fluororesin is uniformly dispersed in the plating film. Since the wires are used as braided wires and are braided around the outer circumference of the cable core to form a braided conductor layer, the braided conductor layer itself causes slippage between the braided wires with extremely small force when the cable is bent. This makes it softer and easier to deform than conventional braided conductor layers, and the inner and outer surfaces of the braided conductor layer are maintained at low friction by the action of the solid lubricant contained in the composite plating layer. Therefore, the braided conductor layer also slips between the cable core and the jacket, and these effects combine to create a cable with extremely excellent flexibility. Furthermore, since the braided conductor layer can slide against the jacket and cable core, it is less susceptible to deformation of the jacket and cable core due to bending of the cable, and moreover, the braided conductor layer itself can slide against the jacket and cable core. Since the braided conductor layer can easily follow the deformation while causing slippage between the braided wires, there is no local concentration of stress on each wire of the braided conductor layer, and the bending life is greatly improved.

〔Example〕

The figure is a perspective view showing an embodiment of the cable with a braided conductor layer according to the present invention, in which two insulated wire cores 3 each having an insulator 2 coated on the outer periphery of a conductor 1 are twisted together. A composite plating layer 4 containing a solid lubricant is provided on the outer periphery of a metal wire 5, such as an annealed copper wire, which is braided to form a braided conductor layer 6, which is further covered with a jacket 7.

Here, composite plating is also called dispersion plating or co-optation plating, in which a metal and a nonmetallic substance are combined, and the metal that forms the matrix maintains the properties of the base metal, while the nonmetal has the properties. It is a surface treatment technology created by combining unique properties. Specifically, this is a plating method in which fine particles of non-metallic polymers, ceramics, etc. are suspended in a plating bath, electrolysis is performed, and the fine particles are dispersed and co-deposited with the metal matrix on the surface to be plated.

In this case, as the solid lubricant, fluororesin, silicone resin, graphite, graphite fluoride, molybdenum disulfide, tungsten disulfide, alumina, etc. can be used. The content of the solid lubricant, which becomes the dispersed phase, is effective in reducing the friction between the wires when mixed in at around 10% by volume (solid content equivalent), and it is also possible to further increase the content. When fine powder of polytetrafluoroethylene resin (PTFE) is used as the material, when it is mixed in at about 35% by volume, the surface properties of the composite plating layer become close to those of fluororesin coating, and it has an extremely low coefficient of friction. Become.

Example PTFE fine powder (particle size 0.3 μm) was added to a bath mainly composed of sulfamic acid (600 g of nickel sulfamate, 40 g of nickel chloride, and 35 g of boric acid).
8 g/g was made hydrophilic on the surface with a dispersing agent and at the same time given a positive charge, and suspended at a temperature of 50°C.
Composite plating was performed on the outer periphery of the annealed copper wire under the conditions of ℃ and current density of 2 A/dm ² . The thickness of the resulting composite nickel plating layer was 1 μm, and the PTFE content was 35% by volume.

Regarding the cable of the example in which the braided conductor layer was formed using the braided wire obtained in this way, and the conventional cable using the braided wire made of annealed copper wire without the composite plating layer, the flexible When the cables were compared in terms of strength and bending resistance, the cables of the examples showed significantly superior results in both cases.

In addition to the above-mentioned PTFE as a solid lubricant, fluororesins such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA) or tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP) are also used. The same effect can be obtained when the material is folded, and the same effect can be obtained when using other materials that have self-lubricating properties, such as graphite fluoride, graphite, molybdenum disulfide, tungsten disulfide, alumina, etc. The effect was recognized.

Further, in the above embodiment, a case has been described in which two insulated wire cores are used as the cable core, but of course the number of insulated wire cores may be greater or less than that shown in the drawings. Although not shown, when there is only one insulated wire core, it is also possible to create a so-called low-noise coaxial cable by arranging the above-mentioned braided conductor layer coaxially with respect to the insulated wire core and using it as an outer conductor. be. In other words, conventionally, when mechanical vibration, bending, etc. are applied to a coaxial cable,
A contact potential difference occurs between the cable's outer conductor and the insulated wire core, which causes static electricity noise. Therefore, a semiconductive layer such as conductive plastic is applied between the insulator and the outer conductor to prevent static electricity from occurring in this area. According to the present invention, since the braided conductor layer is soft and has a low friction surface as described above, it has excellent flexibility and bending resistance. In addition, each braided strand is coated with a plating layer containing a solid lubricant such as fluororesin on the outer periphery, which reduces the copper conductivity of the surface area, and there is essentially half a layer inside the braided conductor layer. Since the same effect as that obtained by providing a conductive layer can be obtained, this together with the effect of the low friction of the braided conductor layer results in an extremely excellent low-noise coaxial cable.

〔Effect of the invention〕

As explained above, according to the present invention, a metal wire having a composite plating layer containing a self-lubricating solid lubricant such as fluororesin on the outer periphery is used as a braided wire, and a cable Since the wires are braided around the outer circumference of the core to form a braided conductor layer, slippage easily occurs between the braided strands when the cable is bent, and the inner and outer surfaces of the braided conductor layer are coated with solid lubricant. Since the braided conductor layer has low friction, it also causes slippage between the cable core and the jacket, and the combined effect of both results in a cable with an extremely flexible braided conductor layer. Furthermore, since the braided conductor layer is less constrained by the cable core and jacket during deformation, local stress concentration on each strand of the braided conductor layer is prevented, resulting in a significant improvement in flex life. Ru.

Furthermore, by using a single insulated wire core as the cable core and using the braided conductor layer as the outer conductor, it is possible to reduce static electricity noise when the cable is bent, even without providing a semiconductive layer such as conductive plastic. Therefore, it can also be used as a low-noise coaxial cable.

It should be noted that the present invention is not limited to the above-mentioned embodiments; for example, the matrix metal constituting the composite plating layer may be replaced with a metal other than nickel, such as tin or silver, or the structure of the cable core may be changed. Of course, various modifications can be made within the technical concept of this invention.

[Brief explanation of drawings]

The figure is a perspective view with the end portion of the cable with a braided conductor layer cut away according to the present invention. 3: Insulated wire core, 4: Composite plating layer, 5: Metal wire, 6: Braided conductor layer, 7: Jacket.

Claims (1)

[Claims] 1. A composite conductor layer comprising at least one insulated wire core and a braided conductor layer formed by braiding metal wires provided on the outer periphery of the wire core, the composite material containing a solid lubricant on the outer periphery of the metal wire. A cable with a braided conductor characterized by having a plating layer. 2. In the cable with a braided conductor layer according to claim 1, the solid lubricant is one selected from fluororesin, silicone resin, graphite, graphite fluoride, molybdenum disulfide, tungsten disulfide, alumina, or A cable with a braided conductor layer comprising two or more types. 3. In the cable with a braided conductor layer according to claim 1 or 2, the braided conductor layer includes one insulated wire core inside thereof, and is formed as a whole on a coaxial cable. A cable with a braided conductor layer.