Cable

Abstract

The invention provides a cable which can perform smooth bending operation and has improved durability. The cable is formed by coating a conductor part, which is formed by arranging a conductor in a spiral shape in the length direction, with an insulating coating material having an insulating property, and is provided with the following components: the conductor part which is formed by twisting a plurality of bare wires to form a core wire and arranging a plurality of the core wires in a circular ring shape in a close contact manner; and a reinforcing part which is composed of a rope body formed by a plurality of yarns made of a fiber material and is compressed and accommodated in a central space formed by the annular core wires of the conductor part in a substantially linear manner, and the rope body is pressed into the central space.

Description

Technical Field

[0001] The present invention relates to a cable composed of a plurality of conductors, and more particularly to a cable having improved durability. Background Art

[0002] In recent years, the demand for cables with high wiring workability has increased, led by the development of the robot industry. Such cables are often used as large current power lines with larger conductor sizes in applications such as the sliding parts of handling robots and welding power cables. On the other hand, they are often used in repeated bending operations. Therefore, high durability against long-term repeated bending operations is required.

[0003] From this point of view, conventional cables have often been constructed with conductors twisted in concentric circles, insulated with PVC (polyvinyl chloride), and covered with a PVC sheath so that the cable cross section becomes circular in order to improve flexibility and durability.

[0004] For example, as an existing cable, the following cable is known: it has a conductor formed by twisting multiple sub-twisted conductors in a single-layer twisted structure, in the structure of the cut surface of the conductor cut in a direction perpendicular to the length direction, a gap is formed in the center of the multiple sub-twisted conductors, and supplementary components are twisted between the sub-twisted conductors and the sub-twisted conductors respectively (see patent document 1).

[0005] In addition, as a conventional cable, for example, there is known a cable in which an insulating core formed by coating a conductor with rubber or vinyl resin is twisted together with a plurality of interlayer jute inserted in the gap, and a rubber or plastic sheath is applied to the outer periphery (see Patent Document 2).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2020-119857

[0009] Patent Document 2: Japanese Utility Model Publication No. Showa 56-76219 Summary of the invention

[0010] Problems to be solved by the invention

[0011] For example, for a cable having a gap formed in the center of a plurality of sub-twisted conductors as in the above-mentioned patent document 1, when the cable is operated, the overall shape of the cable is easily flattened starting from the gap in the center, which easily induces damage to the sub-twisted conductors, and there is a problem of low durability. In addition, for a cable composed of a plurality of separately covered insulating cores as in the above-mentioned patent document 2, there is a problem that it is difficult to obtain a sufficiently large current when the generated current is represented by the total value of the plurality of independently isolated insulating cores. In addition, for a cable composed of a plurality of such insulating cores, there is a problem that the outer diameter becomes larger and the manufacturing cost increases due to the division of the internal conductor and the insulation and tape winding of the divided conductors.

[0012] In addition, for cables using PVC insulation and PVC sheaths, such as cables with rubber or plastic sheaths as described in Patent Document 2, since rubber has low elasticity, there is a problem that stress generated when the cable is twisted or bent will be locally generated, causing the cable to be easily damaged and having low durability.

[0013] That is, when conventional cables are used as power lines for large currents, thick conductors are required. However, if the cable is bent or twisted, the thick conductors move inside the insulation, causing the conductors to interfere with each other and be damaged, resulting in reduced durability.

[0014] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a cable that can perform a smooth bending operation and has improved durability.

[0015] Methods used to solve problems

[0016] The present inventors have conducted intensive studies and, as a result, have found a cable having improved durability by studying its arrangement structure, thereby completing the present invention.

[0017] Thus, the cable disclosed in the present application is a cable formed by a conductor portion formed by spirally arranging a conductor in a length direction and covered by an insulating coating material having insulating properties, and comprises a conductor portion and a reinforcement portion; the conductor portion is formed by twisting a plurality of bare wires to form a core wire and arranging a plurality of the core wires in close contact in a circular ring shape; the reinforcement portion is composed of a rope body formed by a plurality of yarns of a fiber material, and the rope body is compressed and accommodated in a central space formed by the circular core wire of the above-mentioned conductor portion in a roughly linear shape; the above-mentioned rope body is pressed into the above-mentioned central space.

[0018] Thus, in the cable disclosed in the present application, the conductor portion formed by spirally arranging the conductor in the length direction is formed by covering with an insulating coating material having insulating properties; the cable comprises a conductor portion and a reinforcement portion; the conductor portion is formed by twisting a plurality of bare wires to form a core wire and arranging the plurality of the core wires in close contact in a circular ring shape; the reinforcement portion is composed of a rope body formed by a plurality of yarns of a fiber material, and the rope body is compressed and accommodated in a central space formed by the circular core wire of the above-mentioned conductor portion in a substantially straight shape; the above-mentioned rope body is pressed into the above-mentioned central space; therefore, the rope body is pressed into the central portion of the cable, and the amount of the rope body inserted into the above-mentioned central portion is greater than the theoretically calculated cross-sectional area, the contact pressure between the bare wires is reduced, and the rope body having a buffering property in the central portion supports the cable with a force from the central portion of the cable toward the outer periphery of the cable in a radial direction, so that the durability of the cable is greatly improved, for example, the durability of the cable in a torsional action performed by a welding robot is greatly improved, thereby suppressing the occurrence of cable breakage. In addition, since the sub-strands are composed of bare wires that are not isolated from each other by insulating parts or tapes, high processability can be achieved, which allows for easy connection of the end portions. Compared with the prior art where it is necessary to strip the coated wires of multiple sub-strands and connect them at the end portions, the operation becomes easier and the manufacturing cost can be suppressed.

[0019] According to the need, in the cable disclosed in the present application, the cross-sectional area of ​​the rope body when naturally loaded is formed to be larger than the cross-sectional area of ​​the central space. In this way, since the cross-sectional area of ​​the rope body when naturally loaded is formed to be larger than the cross-sectional area of ​​the central space, the rope body as an intervening object is pressed into the central portion in a highly compressed state, thereby forming the cable in a state where the rope body maintains high flexibility, the cushioning property of the rope body is improved, and the durability of the cable can be further improved.

[0020] According to the need, in the cable disclosed in the present application, the rope body is made of synthetic fibers. In this way, since the rope body is made of synthetic fibers, the rope body made of highly flexible synthetic fibers is pressed into the central portion of the cable, and the amount of the rope body inserted into the central portion is easily larger than the theoretically calculated cross-sectional area, thereby reducing the contact pressure between the bare wires, and the rope body made of synthetic fibers having a buffering property in the central portion supports the cable with a force from the central portion of the cable to the outer periphery of the cable in a radial direction, thereby making it possible to reliably maintain the rope body in a flexible state to form the cable, and further improve the durability of the cable.

[0021] According to the need, in the cable disclosed in the present application, the reinforcing portion accommodates the rope body in the central space at a period less than the spiral period of the conductor portion. In this way, since the reinforcing portion accommodates the rope body in the central space at a period less than the spiral period of the conductor portion, the rope body as an intervening object made of synthetic fibers is pressed into the central portion in a state close to a straight insertion state maintaining a high straight state, thereby forming the cable while maintaining a soft state, thereby further improving the cushioning property of the rope body and further improving the durability of the cable.

[0022] According to the requirements, in the cable disclosed in the present application, the core wires are in close contact with each other at multiple points in a linear manner. In this way, since the core wires are in close contact with each other at multiple points in a linear manner, the contact area of ​​the bare wires is in contact with each other with a larger surface area, which can alleviate the generation of heat and voltage drop in the event of cable damage, and further improve safety.

[0023] According to the requirements, in the cable disclosed in the present application, the diameter of the conductor part is 3 to 6 times the diameter of the core wire. In this way, since the diameter of the conductor part is 3 to 6 times the diameter of the core wire, the ratio of the core wire diameter to the diameter of the conductor part is optimized, the stress caused by the torsional action and the interference between the bare wires can be reduced, and the durability can be optimally improved according to the optimal filling degree of the core wire.

[0024] According to the requirements, in the cable disclosed in the present application, the diameter of the core wire is 8 to 60 times the diameter of the bare wire. In this way, since the diameter of the core wire is 8 to 60 times the diameter of the bare wire, the ratio of the core wire diameter to the conductor diameter of the bare wire can be optimized, the generation of stress caused by torsion can be reduced, and the durability can be optimally improved according to the optimal filling degree of the bare wire.

[0025] According to the need, in the cable disclosed in the present application, a gap is formed in the area formed between the adjacent conductor parts and the insulating coating material. Thus, since the gap is formed in the area formed between the adjacent conductor parts and the insulating coating material, when the cable is used with repeated actions such as twisting actions in welding robots, the gap plays a buffering role, thereby greatly improving the durability of the cable, suppressing the occurrence of wire breakage, and since the cutting process of the components in the area is not required, the processability is improved, and the manufacturing cost can be suppressed.

[0026] According to the need, in the cable disclosed in the present application, the conductor part is composed of 6 to 15 core wires. In this way, since the conductor part is composed of 6 to 15 core wires, the ratio of the core wires to the conductor part is optimized, the stress caused by the torsional action and the interference between the bare wires can be reduced, and the durability can be optimally improved according to the optimal filling degree of the core wires. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A diagram showing the configuration of a cable according to a first embodiment of the present invention.

[0028] Figure 2 An explanatory diagram for explaining the relationship between adjacent core wires of the cable according to the first embodiment of the present invention is shown.

[0029] Figure 3 An explanatory diagram for explaining the diameter of a conductor portion and the diameter of a core wire of a cable according to a first embodiment of the present invention is shown.

[0030] Figure 4 Explanatory diagrams for explaining the diameter of a core wire and the diameter of a bare wire of a cable according to the first embodiment of the present invention are shown.

[0031] Figure 5 An explanatory diagram for explaining the structure of a cable according to a first embodiment of the present invention is shown.

[0032] Figure 6 An explanatory diagram for explaining the press-fitting of the cable body according to the first embodiment of the present invention is shown.

[0033] Figure 7 A diagram showing the configuration of a cable according to a second embodiment of the present invention.

[0034] Figure 8 Calculation results of the cable outer diameter corresponding to the number of core wires of the cable according to Example 1 of the present invention are shown.

[0035] Fig. 9 The measurement results of the torsion test of the cable according to Example 2 of the present invention are shown.

[0036] Fig.10 The results of the torsion test of the cable according to Example 2 of the present invention are shown for each cable appearance (conductor appearance). DETAILED DESCRIPTION

[0037] (First Embodiment)

[0038] like Figure 1As shown, the cable of the first embodiment is a cable formed by a conductor portion 1 in which a conductor is spirally arranged in the length direction and is covered by an insulating coating material 3 having insulating properties, and the cable comprises a conductor portion 1 and a reinforcement portion 2; the conductor portion 1 is formed by twisting a plurality of bare wires 11 to form a core wire 12 and arranging a plurality of the core wires 12 in close contact in a circular shape; the reinforcement portion 2 is composed of a rope body 21 formed by a plurality of yarns 21a of a fiber material, and the rope body 21 is compressed and accommodated in a central space formed by the circular core wire 12 of the conductor portion 1 in a substantially linear shape; and the rope body 21 is pressed into the central space.

[0039] The conductor part 1 is formed by arranging the core wire 12 in a spiral shape. That is, the conductor part 1 is formed by twisting the core wire 12 in the longitudinal direction.

[0040] The core wire 12 is formed by twisting a plurality of the bare wires 11. That is, it can be formed into a multi-twisted conductor. The twisting method is not particularly limited, and it can be rope twisting (rope twisting) or bundle twisting (collective twisting). In addition, the correlation between the conductor twisting direction (conductor mother twisting direction) and the bundle twisting direction is not particularly limited, and is preferably in the same direction, which can exert high durability compared to the case where the twisting directions are different directions.

[0041] The outer diameter of the conductor part 1 is preferably 0.85 times or more of the theoretical calculated value (i.e., not less than "theoretical outer diameter value - 15%"). For example, it can be 0.85 to 0.98 times of the theoretical calculated value. When the bare wires 11 of the conductor part 1 are partially in contact with each other and flattened, the outer diameter of the conductor part 1 will decrease. If the outer diameter of the conductor part 1 is less than 0.85 times of the theoretical calculated value, the contact pressure will increase and the durability will decrease.

[0042] The conductor part 1 is not particularly limited as long as the core wires 12 are arranged in a concentric circle shape, but preferably has a structure in which the core wires 12 are twisted and arranged in one layer.

[0043] The material of the bare wire 11 is not particularly limited, and for example, a copper wire can be used. In addition, from the perspective of excellent durability, a metal-plated copper wire can be used. In addition, a soft copper wire having a smooth surface and being a soft electrical copper wire can be used, in which case, higher flexibility and conductivity can be obtained compared to a hard copper wire. From such a viewpoint, as a conductor constituting the bare wire 11, for example, a tinned (Sn) soft copper wire can be used, which can improve the corrosion resistance of the conductor surface.

[0044] In addition, the conductor part 1 is formed by arranging a plurality of core wires 12 in close contact in a circular ring shape. Since the plurality of core wires 12 are in close contact, the adjacent core wires 12 have electrical contacts with each other, and the core wires 12 arranged in the circular ring function as a conductor bundle, making it easy to obtain a large current and also improving electrical safety. In addition, since the adjacent core wires 12 have electrical contacts with each other, it is easy to meet the safety standards of the equipment.

[0045] More preferably, if Figure 2 As shown, the adjacent core lines 12 are in close contact with each other at a point a and a point b as a plurality of points, and are in a linearly close contact state along a straight line L formed by the plurality of points a and b. Figure 2 As shown, the adjacent core wires 12 are in contact at points c and d, which are multiple points, and are in a state of linear close contact along a straight line M formed by the multiple points of the points c and d. That is, as an appearance, from a macroscopic point of view, the adjacent core wires 12 are in a state of so-called surface contact with each other.

[0046] In this way, since the core wires 12 are closely contacted with each other at multiple points in a linear manner, the contact area of ​​the core wires 12 is in contact with each other with a larger surface area, which can alleviate the generation of heat and voltage drop in the event of cable damage, and further improve safety. In addition, since the core wires 12 are not isolated by other insulating components, winding tapes, etc., the durability is improved, the processability is also good, and the electrical safety can also be improved.

[0047] like Figure 3 As shown, the correlation between the diameter D of the conductor part 1 and the diameter d of the core wire 12 is not particularly limited, but the diameter D of the conductor part 1 is preferably 3 to 6 times the diameter d of the core wire 12 (including two end values ​​3 and 6, the same below).

[0048] That is, the diameter ratio D / d is preferably 3-6, and more preferably 3.5-5.

[0049] When the diameter ratio D / d is less than 3, the interference between the core wires 12 may increase. On the other hand, when the diameter ratio D / d is greater than 6, the stranded outer diameter of the core wire 12 increases, which may easily lead to increased manufacturing costs and increased outer diameter.

[0050] Furthermore, if the core wire 12 is twisted in two layers, the core wires 12 of the first layer and the second layer interfere with each other, and durability is reduced. Therefore, the core wire 12 is preferably a single-layer structure with a diameter ratio D / d of 3 to 6.

[0051] In this way, since the diameter of the conductor part 1 is 3 to 6 times the diameter of the core wire 12, the ratio of the diameter of the core wire 12 to the diameter of the conductor part 1 is optimized, which can reduce the stress caused by the torsional action and the interference between the bare wires 11, and can optimize the durability according to the optimal filling degree of the core wire 12.

[0052] like Figure 4 As shown, the correlation between the diameter d of the core wire 12 and the diameter d1 of the bare wire 11 constituting the core wire 12 is not particularly limited, but the diameter d of the core wire 12 is preferably 8 to 60 times the diameter d1 of the bare wire 11. That is, the diameter ratio d / d1 is preferably 8 to 60 (including two end values ​​8 and 60, the same below).

[0053] For example, based on the results calculated under the conditions that the total cross-sectional area of ​​the cable is 8 to 55 sq, the number of core wires is 12 to 15, and the diameter of the wire (bare wire 11) is 0.08 to 0.12 mm, the diameter ratio d / d1 is within the range of 8 to 60 regardless of whether it is calculated in a bundle twisted manner or in a 7-wire twisted manner.

[0054] For example, when the wires (bare wires 11) are twisted into 7 strands, the total cross-sectional area of ​​the cable is 8sq, the number of core wires 12 is 15, and the wire (bare wire 11) diameter is 0.12mm, the diameter ratio d / d1 is calculated to be 9. Also, when twisting 7 strands, for example, the total cross-sectional area of ​​the cable is 55sq, the number of core wires 12 is 6, and the bare wire (bare wire 11) diameter is 0.08mm, the diameter ratio d / d1 is calculated to be 56.

[0055] For example, when the wires (bare wires 11) are bundle-twisted, the total cross-sectional area of ​​the cable is 8sq, the number of core wires 12 is 15, and the wire (bare wire 11) diameter is 0.12mm. The diameter ratio d / d1 is calculated to be 8. Also, in the case of bundle twisting, for example, the total cross-sectional area of ​​the cable is 55sq, the number of core wires 12 is 6, and the wire (bare wire 11) diameter is 0.08mm. The diameter ratio d / d1 is calculated to be 49.

[0056] In this way, since the diameter of the core wire 12 is 8 to 60 times the diameter of the bare wire 11, the ratio of the diameter of the core wire 12 to the conductor diameter of the bare wire 11 is optimized, which can reduce the generation of stress caused by torsional action and can optimally improve durability according to the optimal filling degree of the bare wire 11.

[0057] The number of the core wires 12 is not particularly limited, but is preferably 6 to 15 (both inclusive), more preferably 8 to 12, and for example 10, which can improve torsional durability.

[0058] The reason for this is that when the number of the core wires 12 is less than 6, the durability is reduced, and when it is more than 15, the outer diameter is enlarged and the manufacturing cost is increased. In order to avoid the enlargement of the outer diameter, when the core wires 12 are made into two layers of twist, the core wires 12 constituting the first layer and the second layer of the two-layer twist interfere with each other, resulting in reduced durability.

[0059] In this way, the conductor part 1 is composed of 6 to 15 core wires 12, so that the ratio of the core wire 12 to the conductor part 1 is optimized, which can reduce the stress caused by the torsional action and the conductor interference between the bare wires 11, and can optimize the durability according to the optimal filling degree of the core wire 12.

[0060] like Figure 5 As shown, in the reinforcing part 2, the rope body 21 is compressed and accommodated in a substantially linear shape along the linear direction A in the central space formed by the annular core wire 12 of the conductor part 1. That is, the rope body 21 is pressed into the central space. Pressing means a state of being squeezed in by applying pressure.

[0061] The fact that the rope body 21 is substantially straight means that Figure 5 As shown, the rope body 21 is accommodated in the central space in a shape along the linear direction A which is the running direction (length direction) of the cable, and maintains a substantially linear shape.

[0062] For example, even if the rope body 21 is partially or locally slightly bent, Figure 5 As shown in FIG. 1 , if the shape along the straight direction A is viewed as a whole, it can be said that the rope body 21 is in a straight state, which is also included in the state in which the rope body 21 is in a substantially straight state.

[0063] More preferably, the rope 21 is accommodated in the central space at a period smaller than the spiral period of the conductor 1. That is, the rope 21 as an intervening object is formed in a state close to a straight line without twisting with respect to the bare wires 11 twisted in a spiral.

[0064] Thus, the rope body 21 as an interposed object is pressed into the central portion in a state of linear insertion close to a straight state maintaining high linearity, and the rope body 21 maintains a soft state rather than a hard state of a twisted state to form a cable, thereby further improving the cushioning properties of the rope body 21 and further improving the durability of the cable.

[0065] The rope body 21 is composed of a plurality of yarns 21a of a fiber material. Figure 6 As shown in (a) of FIG. 8 , the rope body 21 can be composed of a plurality of twisted yarns 21a.

[0066] The rope body 21 is preferably configured as Figure 6 The diameter e of the cross section when naturally loaded as shown in (b) is greater than Figure 6 (c) shows a diameter E of a cross section of a central space formed in a portion closer to the center of the cable than the conductor portion 1 .

[0067] Therefore, if Figure 6 As shown in (d), the cross-sectional area of ​​the rope body 21 constituting the reinforcement part 2 when naturally loaded is larger than the cross-sectional area of ​​the central space of the cable, and is configured to be larger than the cross-sectional area of ​​the central space. In this way, the rope body 21 as an intervening object is pressed into the central part in a highly compressed state, thereby forming a cable while maintaining a high softness, and the cushioning property of the rope body 21 is improved, which can further improve the durability of the cable.

[0068] The rope body 21 is not particularly limited as long as it is made of a fiber material, and may be made of a natural material. However, from the viewpoint of homogeneous quality and cost, it is preferably made of synthetic fibers.

[0069] There is no particular limitation on the synthetic fiber, and examples thereof include polyester resins, acrylic resins, rubber resins, vinyl alkyl ether resins, silicone resins, polyamide resins, urethane resins, fluorine resins, and epoxy resins. In view of ease of operation, polyester is preferably used, polyester is more preferably used, and cotton-like polyester is further preferably used. For example, a polyester non-woven fabric can be made into three-count yarns 21a and three strands can be twisted together, and a plurality of such yarns can be used as the rope body 21 for the sandwich object.

[0070] In this way, since the rope body 21 is made of synthetic fibers, the rope body 21 made of highly soft synthetic fibers is pressed into the central part of the cable, so that it is easy to make the amount of rope body 21 inserted into the central part larger than the theoretically calculated cross-sectional area, thereby reducing the contact pressure between the bare wires 11, and the rope body 21 made of synthetic fibers having a buffering property in the central part supports the cable with a force radially from the central part of the cable toward the outer periphery of the cable, thereby enabling the rope body 21 to reliably maintain a soft state to form a cable, which can further improve the durability of the cable.

[0071] The insulating covering material 3 covering the conductor part 1 is not particularly limited as long as it is an insulating component. For example, it can be composed of the following multiple components, namely: a pressing band 31 covering the outer periphery of the conductor part 1 and pressing and fixing the conductor part 1 in a band shape, an insulating material 32 covering the outer periphery of the pressing band 31, and a sheath 33 covering the outer periphery of the insulating material 32 and preventing damage to the cable.

[0072] The material of the pressing belt 31 is not particularly limited, and for example, a fluororesin belt may be used. Examples of such fluororesins include PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), ETFE (tetrafluoroethylene-ethylene copolymer), PVDF (polyvinylidene fluoride), PCTFE (polychlorotrifluoroethylene), ECTFE (chlorotrifluoroethylene-ethylene copolymer), PTFE (polytetrafluoroethylene) and the like. By using such a belt, the durability can be further improved due to its high sliding and high elasticity and flexibility, thereby not constraining the conductor part 1 inside the cable.

[0073] The insulating material 32 is preferably made of a material having higher flexural elasticity than the material of the sheath 33 .

[0074] The material of the insulating material 32 is not particularly limited as long as it is an insulating component. For example, various resins such as ester thermoplastic elastomer (TPEE), olefin thermoplastic elastomer (TPO), polyurethane thermoplastic elastomer (TPU) and amide thermoplastic elastomer (TPAE) can be used. More specifically, for example, PEs (polyester), PBT (polybutylene terephthalate), PE (polyethylene), PP (polypropylene), PA6 (polyamide 6), PA11 (polyamide 11), PA12 (polyamide 12), PET (polyethylene terephthalate), PBN (polybutylene naphthalate), PVDF (polyvinylidene fluoride), ETFE (ethylene-tetrafluoroethylene copolymer), PTFE (polytetrafluoroethylene), PPS (polyphenylene sulfide), PEEK (polyetheretherketone), EVOH (ethylene vinyl alcohol copolymer), ABS (acrylonitrile-butadiene-styrene), EVA (ethylene vinyl alcohol) or PI (polyimide) can be used.

[0075] For example, a polyester elastomer can be used as the insulating material 32. In this case, it has a higher bending elasticity than PVC and has a hardness property, which can prevent the torsional stress from being concentrated on the end portion. In addition, since it can be formed by tube extrusion, it can maintain durability without constraining the conductor, and can reduce the stress on the core wire 12 during cable manufacturing, so that a high-quality cable can be manufactured.

[0076] In addition, the rigidity of the insulating material 32 is not particularly limited, but preferably has a rigidity of 50 MPa to 400 MPa, and more preferably has a rigidity of 70 MPa to 300 MPa, from the viewpoint of improving durability. From this point of view, it is preferred to select an insulating material 32 of a grade that can withstand 10 million times even when bent at a bending radius of 6D (mm).

[0077] The material of the sheath 33 is not particularly limited, and examples thereof include PVC (polyvinyl chloride), PE (polyethylene), FEP (Teflon (registered trademark)), Teflon), etc. From the perspective of ease of operation, PVC (polyvinyl chloride) which is flexible and flame-retardant and oil-resistant and has a proven track record in welding robot cables can be used.

[0078] In this way, the rope body 21 is pressed into the central part of the cable, and the capacity of the rope body 21 inserted into the central part is larger than the theoretically calculated cross-sectional area, so the contact pressure between the bare wires 11 becomes lower, and the rope body 21 with a buffering property in the central part supports the cable with a force radially from the central part of the cable toward the outer periphery of the cable, thereby greatly improving the durability of the cable. For example, the durability of the cable in a torsional action performed by a welding robot is greatly improved, thereby preventing the occurrence of cable breakage.

[0079] In addition, since the bare wires 11 (sub-stranded wires) are isolated from each other without utilizing insulating components, the terminal end can be easily joined to obtain high processability. Compared with the prior art in which it is necessary to strip the coated wires of the multiple sub-stranded wires constituting the cable and join them at the terminal end, the handling becomes easier and the manufacturing cost can be suppressed.

[0080] (Second Embodiment)

[0081] The cable 10 of the second embodiment is similar to the first embodiment, and includes the conductor portion 1, the conductor portion 1 and the reinforcing portion 2, and further includes: Figure 7 As shown, a gap 13 is formed in a region formed between the adjacent conductor portion 1 and the insulating coating material 3 .

[0082] The gap 13 preferably occupies at least a portion of a region formed between the adjacent conductor portion 1 and the insulating coating material 3 , and more preferably occupies the entire region.

[0083] Thus, since the gap 13 is formed in the region formed between the adjacent conductor portion 1 and the insulating coating material 3, when the cable is used with repeated movements such as twisting movements in welding robots, the gap 13 acts as a buffer, thereby greatly improving the durability of the cable and suppressing the occurrence of disconnection. In addition, since the cutting process of the components in this region is not required when manufacturing the cable, the processability is improved and the manufacturing cost can be suppressed.

[0084] In order to further clarify the features of the present invention, examples are described below, but the present invention is not limited to these examples.

[0085] (Example 1)

[0086] (1) Cable production

[0087] According to the above-mentioned first embodiment, the cable of Example 1 was produced using the following components.

[0088] <Components>

[0089] Core wire 12: tinned soft copper wire (twisted conductor) (each cable has a cross-sectional area of ​​2sq × 10 wires)

[0090] Rope 21: Polyester (interlayer with high cushioning properties)

[0091] Pressing belt 31: Fluorine belt

[0092] Insulation material 32: polyester elastomer

[0093] Sheath 33: PVC

[0094] ·Outer diameter of conductor 1: 9.2 (theoretical ratio)

[0095] (2) Verification of the number of core wires

[0096] The outer diameter of the cable varies depending on the number of core wires 12 constituting the cable (the number of core wires). Figure 8 Calculation results of the outer diameter when a 22 sq conductor is divided into 1 to 12 parts (when the number of core wires is 1 to 12) are shown in FIG.

[0097] As mentioned above, the number of core wires is preferably 6 to 15. Figure 8 The measurement results showed that from the viewpoint of miniaturizing the outer diameter of the cable, 8 to 12 cables are more preferable. This confirmed that the outer diameter of the cable can be miniaturized, and a compact and highly durable cable can be realized.

[0098] (Example 2)

[0099] The torsion durability comparison test of the cable produced in Example 1 and the existing cable HMV (c10681) AWG4 (22) / 1C (produced by Daiden Co., Ltd.) was conducted. The test conditions are as follows: Fig. 9 As shown in (a), the distance L between the fixed end and the running end of the target cable is 200 mm, the torsion angle θ is ±180°, and the torsion repetition number is 5 million times.

[0100] The obtained results are shown in Fig. 9 (b). According to the results, in the cables of the existing products, 36.7% of the conductor wires (bare wires 11) were found to be broken. In contrast, in the cables of this embodiment, 0.21% of the conductor wires (bare wires 11) were found to be broken, and almost no breakage occurred. Therefore, the difference in durability from the existing products is significant, and extremely high durability is confirmed.

[0101] In addition, the results of the torsion test of each cable appearance (conductor appearance) are as follows Fig.10 As shown. According to the obtained results, in the cable of the existing product, deformation of the conductor was confirmed after 5 million repetitions of twisting, on the other hand, in the cable of this embodiment, such deformation of the conductor did not occur, and the difference in durability from the existing product was also significant in appearance, and extremely high durability was confirmed.

[0102] Description of Reference Numerals

[0103] 1…conductor part, 11…bare wire, 12…core wire, 13…gap, 2…reinforcement part, 21…rope body, 21a…yarn, 3…insulating coating material, 31…pressing tape, 32…insulating material, 33…sheath.

Claims

1. A cable, wherein a conductor portion formed by spirally arranging a conductor in a longitudinal direction is covered with an insulating coating material having insulating properties, characterized in that: The cable comprises a conductor portion and a reinforcement portion. The conductor part is formed by twisting a plurality of bare wires to form a core wire and arranging the plurality of core wires in close contact in a circular ring shape. The reinforcing part is composed of a rope body formed by a plurality of yarns of a fiber material, and the rope body is compressed and accommodated in a substantially linear shape in a central space formed by the annular core wire of the conductor part; The rope body is pressed into the central space.

2. The cable according to claim 1, characterized in that The cross-sectional area of ​​the rope body when naturally placed is formed to be larger than the cross-sectional area of ​​the central space.

3. The cable according to claim 1, characterized in that The rope body is made of synthetic fibers.

4. The cable according to claim 1, characterized in that The reinforcing portion accommodates the rope body in the central space at a period smaller than a spiral period of the conductor portion.

5. The cable according to claim 1, characterized in that The core wires are in close linear contact with each other at a plurality of points.

6. The cable according to claim 1, characterized in that The diameter of the conductor part is 3 to 6 times the diameter of the core wire.

7. The cable according to claim 1, characterized in that The diameter of the core wire is 8 to 60 times the diameter of the bare wire.

8. The cable according to claim 1, characterized in that A gap is formed in a region formed between the adjacent conductor portions and the insulating coating material.

9. The cable according to any one of claims 1 to 8, characterized in that: The conductor portion is composed of 6 to 15 core wires.

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