JP7294258B2 - composite cable - Google Patents

Description

The present invention relates to composite cables.

2. Description of the Related Art Conventionally, composite cables are known in which a signal line for signal transmission and a power line for power supply are combined. For example, Patent Literature 1 discloses a composite cable in which a cable core is formed by twisting a twisted pair wire obtained by twisting a pair of signal wires and a plurality of power wires. The composite cable of Patent Document 1 is used, for example, as wiring for vehicles such as automobiles.

JP 2020-47599 A

By the way, industrial robots such as robot arms used in factories and the like are becoming smaller, and parts such as servo motors used in industrial robots are also becoming smaller. It is difficult to connect multiple cables to a small servomotor, etc., and the wiring space for cables in industrial robots tends to be narrow. There is a demand to use a composite cable in which a signal line and a power line are integrated into one, instead of using separate cables for signal transmission.

Furthermore, since industrial robots generally have many moving parts, composite cables connected to servo motors, etc. are required to have bending resistance and twisting resistance that can withstand repeated bending and twisting. .

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a composite cable having excellent resistance to bending and twisting.

In order to solve the above-mentioned problems, the present invention provides a first power line in which a twisted wire obtained by twisting a plurality of signal lines and a plurality of first power lines are arranged adjacent to each other in the circumferential direction of the cable. A power wire unit, a second power wire unit having an even number of second power wires, and an assembly in which the twisted wire, the plurality of first power wires, and the plurality of second power wires are twisted together a sheath that collectively covers the periphery, wherein the stranded wire and the first power wire unit are arranged to face each other in the cable diameter direction, and the second power wire unit is arranged in the cable circumferential direction An even number of the second power wires are arranged to face each other between the twisted wires and the first power wire unit, and the rigidity of the first power wire unit is the same as the above. Provided is a composite cable whose rigidity is 1 to 1.5 times that of a stranded wire.

ADVANTAGE OF THE INVENTION According to this invention, the composite cable excellent in bending resistance and twisting resistance can be provided.

1 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of a composite cable according to one embodiment of the present invention; FIG.

[Embodiment]
BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of the composite cable according to this embodiment. The composite cable 1 is a cable that combines a signal line for signal transmission and a power line for power supply, and is connected to, for example, a servomotor of an industrial robot or the like, for signal transmission to the servomotor or the like. and power supply. Signal lines are used, for example, to transmit signals in a frequency band of 1 MHz or higher. Also, the power line is used, for example, to supply a current of about several amperes. Such signals and currents are transmitted and supplied in the section between the servo motor and the movable part of the industrial robot, so that the movable part of the industrial robot moves and stops repeatedly at high speed. . In addition, the application of the composite cable 1 is not limited to this.

Further, since industrial robots are used in factories and the like, it is assumed that long-distance transmission of, for example, about 100 m at maximum will be performed with composite cables connected to servo motors of industrial robots. Therefore, composite cables used for such applications are also required to have good electrical properties that enable long-distance transmission. For example, it is conceivable to increase the outer diameter of the composite cable in order to cope with long-distance transmission, but in this case, bending resistance and twisting resistance are lowered. Therefore, in the composite cable, long-distance transmission is possible without increasing the outer diameter of the composite cable (for example, when the outer diameter of the composite cable is 9.0 mm or less), and bending resistance and twisting resistance are improved. It is also required to be excellent.

As shown in FIG. 1, the composite cable 1 includes a twisted pair wire 2 obtained by twisting a pair of signal wires 21 as a twisted wire in which a plurality of signal wires 21 are twisted together, and a plurality of first power wires 31 adjacent to each other in the cable circumferential direction, a second power line unit 4 having an even number of second power lines 41, a twisted pair wire 2 and a plurality of first A sheath 9 that collectively covers the periphery of an assembly (cable core) 5 in which the power line 31 and the plurality of second power lines 41 are twisted together is provided. In the composite cable 1 shown in FIG. 1, the twisted pair wire 2 obtained by twisting a pair of signal wires 21 is used as the twisted wire, but the twisted wire is not limited to this. As the twisted wire, for example, two or more signal wires 21 may be twisted together, or a plurality of twisted pair wires 2 obtained by twisting a pair of signal wires 21 may be used.

The signal line 21 used for the twisted pair wire 2 has a signal line conductor 21a and a signal line insulator 21b covering the signal line conductor 21a. The signal line conductor 21a is composed of a twisted wire conductor in which a plurality of metal wires are twisted together. The signal wire 21 used as the twisted pair wire 2 is more likely to receive greater stress during bending and twisting than the first power wire 31 and the second power wire 41 that are used without being twisted, and thus has higher bending resistance. and torsion resistance are required. Therefore, in the present embodiment, a composite twisted wire obtained by further twisting a plurality of sub-twisted wires obtained by twisting a plurality of metal wires together is used as the signal line conductor 21a. A tin-plated annealed copper wire having an outer diameter of 0.8 mm or less can be used as the metal wire used for the signal line conductor 21a. The number of metal wires used for the signal line conductor 21a is preferably 100 or more, which is smaller than the number of metal wires used for the first conductor 31a and the second conductor 41a. Such a signal line conductor 21a is effective in improving the rigidity balance of the composite cable 1 and improving the resistance to bending and twisting.

As the signal line insulator 21b, it is desirable to use an insulator with a dielectric constant as low as possible in order to realize good electrical characteristics that enable long-distance transmission. In this embodiment, the signal line insulator 21b made of expanded propylene is used. In order to achieve high bending resistance and twisting resistance, the signal line insulator 21b preferably has a tensile strength of 25 MPa or more and an elongation of 500% or more. Furthermore, in order to achieve high bending resistance and twisting resistance, the signal line insulator 21b is thicker than the first insulator 31b and the second insulator 41b (for example, twice as thick) as will be described later. preferably formed. The thickness of the signal line insulator 21b is, for example, 0.4 mm or more and 0.6 mm or less. The outer diameter of the signal line 21 is larger than the outer diameters of the first power line 31 and the second power line 41 (for example, 1.3 times the first power line 31). The outer diameter of the signal line 21 is, for example, 2.0 mm or more and 2.4 mm or less.

A differential signal is transmitted to a pair of signal lines 21 forming the twisted pair wire 2 . This reduces the influence of external noise and enables stable signal transmission over a long distance of, for example, 100 m. The characteristic impedance of the twisted pair wire 2 is, for example, 80Ω to 100Ω in the TDR method.

The first power line 31 that constitutes the first power line unit 3 has a first conductor 31a and a first insulator 31b that surrounds the first conductor 31a. The first conductor 31a is composed of a stranded conductor obtained by collectively twisting a plurality of metal wires. A tin-plated annealed copper wire having an outer diameter of 0.8 mm or less can be used as the metal wire used for the first conductor 31a. The number of metal wires used for the first conductor 31a is preferably 100 or more. As the first insulator 31b, ETFE (tetrafluoroethylene-ethylene copolymer) that can withstand high voltage was used. Since the first insulator 31b is made of ETFE, it can be made thinner than the signal line insulator 21b of the signal line 21 . Since the thickness of the first insulator 31 b is thin, the outer diameter of the first power supply line 31 can be made smaller than the outer diameter of the signal line 21 . By making the outer diameter of the first power wire 31 smaller than the outer diameter of the signal wire 21, the number of the first power wire 31 is made larger than the number of the twisted pair wires 2, and so on. It becomes easy to adjust the rigidity of the unit 3 to 1 to 1.5 times the rigidity of the twisted pair wire 2 . That is, it becomes easy to adjust the rigidity balance of the composite cable 1 in the cable circumferential direction. Note that the thickness of the first insulator 31b is, for example, 0.2 mm or more. Also, the outer diameter of the first power supply line 31 is, for example, 1.5 mm or more.

In the present embodiment, the first power wire unit 3 is arranged to face the twisted wire pair 2 in the cable diameter direction. The number of first power wires 31 forming the first power wire unit 3 is preferably larger than the number of signal wires 21 forming the twisted pair wire 2 . More specifically, the number of the first power supply lines 31 is more than 1 and 4 times or less than the number of the signal lines 21 (that is, in the case of the twisted pair 2 obtained by twisting a pair of the signal lines 21, the number of the first power lines 31 is 3 or more. 8 or less). In the present embodiment, the first power line unit 3 is configured by arranging three first power lines 31 along the cable circumferential direction. Circumferentially adjacent first power lines 31 are in contact with each other. In addition, the three first power lines 31 have the same outer diameter, material, and the like.

The second power line 41 that constitutes the second power line unit 4 has a second conductor 41a and a second insulator 41b that surrounds the second conductor 41a. The second conductor 41a is composed of a stranded conductor obtained by collectively twisting a plurality of metal wires. As the metal wire used for the second conductor 41a, a tin-plated annealed copper wire having an outer diameter of 0.8 mm or less can be used. The number of metal wires used for the second conductor 41a is preferably 100 or more. As the second insulator 41b, ETFE (tetrafluoroethylene-ethylene copolymer) that can withstand high voltage was used. The tensile strength of the second insulator 41b is greater than the tensile strength of the signal line insulator 21b (here, the tensile strength of polyethylene foam). In addition, the thickness of the second insulator 41b is, for example, 0.2 mm or more. Moreover, the outer diameter of the second power supply line 41 is, for example, 1.5 mm or more.

In the present embodiment, the second power wire unit 4 has an even number of second power wires 41 at each position between the twisted pair wire 2 and the first power wire unit 3 in the cable circumferential direction. They are arranged to face each other. In other words, the second power wire unit 4 is symmetrical with respect to a plane of symmetry S along the direction in which the twisted pair 2 and the first power wire unit 3 face each other through the center of the cable. 41 are arranged (however, some deviation due to manufacturing tolerance etc. is allowed). The number of the second power supply lines 41 is an even number so as to be symmetrical with respect to the plane of symmetry S. As shown in FIG.

In the present embodiment, one second power wire 41 is arranged between the twisted pair wire 2 and the first power wire unit 3 in the circumferential direction, and two second power wires 41 are arranged in total. I am using The second power wire 41 is arranged so as to be in contact with the twisted pair wire 2 and the first power wire 31 respectively. In addition, the number of the second power wires 41 constituting the second power wire unit 4 is not limited to this. Four second power supply lines 41 may be arranged. Here, the first power line 31 and the second power line 41 have the same outer diameter, but the first power line 31 and the second power line 41 may have different outer diameters. Further, although all the second power lines 41 forming the second power line unit 4 have the same configuration here, the second power lines 41 having different configurations may be included. However, the second power supply line 41 needs to be arranged symmetrically with respect to the plane of symmetry S. As shown in FIG.

Thus, in the present embodiment, the conductor configuration (composite twisted wire) of the signal line 21 forming the twisted pair wire 2 is the same as the conductor configuration (aggregate twisted wire) of the first and second power supply line units 3 and 4. different. Further, the outer diameter D1 of the twisted pair wire 2 is larger than the outer diameter of the first power wire 31 and the outer diameter of the second power wire 41 . Furthermore, the outer diameter D1 of the twisted pair wire 2 is less than or equal to the length D2 of the entire first power supply wire unit 3 in the direction perpendicular to the plane of symmetry S (the facing direction of the second power supply wire 41, the horizontal direction in FIG. 1). is. In addition, it is desirable that the first power supply wire unit 3 facing the twisted pair wire 2 is also arranged plane-symmetrically with respect to the plane of symmetry S. As shown in FIG. By setting the outer diameter D1 of the twisted pair wire 2 to be equal to or less than the length D2 of the entire first power wire unit 3, the rigidity of the first power wire unit 3 is 1 to 1.5 times the rigidity of the twisted pair wire 2. Within the range, the balance of stiffness of the composite cable 1 in the cable circumferential direction can be easily adjusted.

In the present embodiment, the twisted pair 2, the first power line unit 3 made up of three first power lines 31, the second power line unit 4 made up of two second power lines 41, and the intermediate 6 The assembly 5 is configured by twisting the . The intervention 6 plays a role of making the outer shape of the cable closer to a circular shape, and is made of, for example, a thread-like body such as staple fiber thread (staple fiber thread). Since the aggregate 5 is formed by twisting the twisted pair 2 and the power wires 31 and 41, the plane of symmetry S is a plane that rotates according to the twist of the aggregate 5 as it moves in the longitudinal direction. becomes. Interposition 6 is provided between twisted wire pair 2 and first power wire unit 3 so that twisted wire pair 2 and first power wire unit 3, which are arranged facing each other in the cable diameter direction, are separated from each other. should be placed. By separating the twisted pair wire 2 and the first power wire unit 3 in this way, the rigidity balance of the composite cable 1 is improved, and the twisted pair wire 2 and the first power wire unit are separated by bending and twisting. 3 is less likely to collapse, and local stress concentration is less likely to occur.

A pressing winding tape 7 is spirally wound around the assembly 5. - 特許庁As the pressing tape 7, a tape-like member made of resin such as PTFE (polytetrafluoroethylene), non-woven fabric, paper, or the like can be used.

A shield layer 8 is provided around the restraint winding tape 7. - 特許庁As the shield layer 8, a braided shield made of braided metal wires can be used. As the metal wire, it is more preferable to use a copper alloy wire having high resistance to bending and twisting. Although an annealed copper wire can be used as the metal wire, in this case, it is desirable to use a thin wire having a diameter of 0.08 mm or more and 0.12 mm or less. Also, a part of the metal wire may be replaced with a copper foil paper in which copper foil is helically wound around a filamentous body.

A drain wire 10 is provided between the restraining tape 7 and the shield layer 8. - 特許庁The drain wire 10 plays a role of making cuts in the shield layer 8 and the sheath 9 at the time of terminal processing to improve terminal processing properties. An annealed copper wire, for example, can be used as the drain wire 10 . The annealed copper wire may have tin plating on its surface.

The sheath 9 is for protecting the assembly 5 and the shield layer 8. For example, a PVC (polyvinyl chloride) resin composition having excellent oil resistance or a urethane resin composition can be used. . The thickness of the sheath 9 is, for example, 0.6 mm or more and 0.8 mm or less. Also, the outer diameter of the sheath 9 (that is, the outer diameter of the composite cable 1) is, for example, 9.0 mm or less. From the viewpoint of ease of routing, the outer diameter of the sheath 9 is preferably 8.6 mm or less.

Here, the bending resistance and twisting resistance of the composite cable 1 are examined. In the composite cable 1, the signal lines 21 are twisted to form the twisted pair 2 so as to be applicable to long-distance transmission. Therefore, in the composite cable 1, the twisted wire pair 2 is included in the assembly 5, and the first power wire unit 3 facing the twisted wire pair 2 is not twisted. That is, in the composite cable 1, sufficient symmetry is not obtained in the direction in which the twisted pair 2 and the first power wire unit 3 face each other. Therefore, stress may concentrate on the twisted pair wire 2 or the first power supply wire 31 when bending or twisting, and sufficient bending resistance and twisting resistance may not be obtained. For example, if the rigidity of the twisted pair wires 2 is much higher than the rigidity of the first power supply wire unit 3, stress is concentrated on the first power supply wires 3 when bending or twisting, and the first power supply wires 3 may disconnect prematurely.

For example, by twisting the first power supply wire unit 3 arranged facing the twisted pair 2, the symmetry of the composite cable 1 is improved, and the stress at the time of bending or the like is reduced between the twisted pair 2 and the first power supply. It is also conceivable to load the line unit 3 substantially evenly. However, in this case, the outer diameter of the composite cable 1 becomes large, and there is a possibility that the bending resistance and the twisting resistance may deteriorate due to the influence of this large diameter.

Therefore, in the present embodiment, the rigidity of the first power supply wire unit 3 is set to 1 to 1.5 times the rigidity of the twisted pair wire 2 . This balances the rigidity of the twisted wire pair 2 and the first power wire unit 3 in the direction facing each other, and applies stress such as bending stress to the twisted wire pair 2 and the first power wire unit 3 substantially evenly. It becomes possible to improve bending resistance and twisting resistance without increasing the outer diameter of the composite cable 1 . The rigidity balance in the direction perpendicular to the plane of symmetry S is ensured by arranging the second power supply lines 41 plane-symmetrically with respect to the plane of symmetry S. As shown in FIG.

Here, the rigidity of the twisted pair wire 2 is obtained by adding together the rigidity of each signal wire 21 represented by the following formula (1) for the pair of signal wires 21 constituting the twisted pair wire 2. be.
(Rigidity of signal line 21) = (conductor cross-sectional area of signal line conductor 21a) x (tensile strength of signal line conductor 21a) + (cross-sectional area of signal line insulator 21b) x (tensile strength of signal line insulator 21b) ... (1)
For example, when an annealed copper wire is used as the metal wire of the signal line conductor 21a, the tensile strength of the signal line conductor 21a is, for example, about 220 MPa. Moreover, when a copper alloy wire is used as the metal element wire of the signal line conductor 21a, the tensile strength of the signal line conductor 21a is, for example, about 850 MPa.

Further, the rigidity of the first power supply line unit 3 is obtained by adding the rigidity of each first power supply line 31 represented by the following formula (2) for the plurality of first power supply lines 31 constituting the first power supply line 31. It is required by
(Rigidity of first power supply line 31) = (conductor cross-sectional area of first conductor 31a) x (tensile strength of first conductor 31a) + (cross-sectional area of first insulator 31b) x (tensile strength of first insulator 31b) strength) (2)

Thus, in the present embodiment, the rigidity of the first power supply wire unit 3 is made equal to or greater than the rigidity of the twisted pair wire 2 . This is because the first power line unit 3 is not twisted and the first power lines 31 can move freely relative to each other. This is because there is a possibility that the effect of rigidity during bending or the like may appear lower than the value obtained. Since the twisted pair wires 2 are twisted together, the signal wires 21 cannot move freely with each other, and it is considered that the effect of rigidity during bending is less likely to decrease. Therefore, it is desirable that the rigidity of the first power supply wire unit 3 is equal to or higher than the rigidity of the twisted pair 2 (1 to 1.5 times the rigidity of the twisted pair 2).

(Actions and effects of the embodiment)
As described above, in the composite cable 1 according to the present embodiment, the twisted pair 2 and the first power wire unit 3 are arranged facing each other in the cable diameter direction, and the second power wire unit 4 , an even number of second power wires 41 are arranged facing each other between the twisted pair 2 and the first power wire unit 3 in the cable circumferential direction, and the first power wires The rigidity of the unit 3 is 1 to 1.5 times the rigidity of the twisted pair wire 2 .

By configuring in this way, the rigidity of the composite cable 1 is well balanced, and when repeatedly bent or twisted, the arrangement of the twisted pair 2 and the power supply wire units 3 and 4 is less likely to collapse, and at the same time, the cable is bent or twisted. The rotation makes it difficult for local stress concentration to occur. As a result, for example, even if the first power wire unit 3 is not twisted, the electric wires constituting the twisted pair 2 and the power wire units 3 and 4 are less likely to break when repeatedly bent or twisted. Flex resistance and twist resistance can be improved while suppressing an increase in diameter of the cable 1 . In addition, in the composite cable 1, since the signal line 21 is twisted and used as the twisted pair line 2, it is possible to stably perform signal transmission over a long distance of, for example, 100 m. A composite cable 1 suitable for signal transmission and power supply to a servomotor or the like of an industrial robot can be realized.

(Summary of embodiment)
Next, technical ideas understood from the embodiments described above will be described with reference to the reference numerals and the like in the embodiments. However, each reference numeral and the like in the following description do not limit the constituent elements in the claims to the members and the like specifically shown in the embodiment.

[1] A first power line unit (3) in which a twisted wire obtained by twisting a plurality of signal lines (21) and a plurality of first power lines (31) are arranged adjacent to each other in the cable circumferential direction ), a second power line unit (4) having an even number of second power lines (41), the twisted wire, the plurality of first power lines (31), and the plurality of second power lines ( 41), and a sheath (9) that collectively covers the periphery of the assembly (5) in which the twisted wires and the first power wire unit (3) are opposed to each other in the cable diameter direction. and the second power wire unit (4) has an even number of second power wires ( The composite cable ( 1).

[2] The twisted wire is composed of a twisted pair wire (2) obtained by twisting a pair of the signal wires (21), and the signal wire (21) includes a signal wire conductor (21a) and the signal wire conductor (21a). and a signal line insulator (21b) covering the circumference of (21a), and the first power supply line (31) includes a first conductor (31a) and a first conductor (31a) covering the circumference of the first conductor (31a). 1 insulator (31b), and the rigidity of the twisted pair (2) is expressed by the following formula for the pair of signal lines (21) constituting the twisted pair (2): It is obtained by adding the stiffness of each signal line (21),
(Rigidity of signal line (21)) = (conductor cross-sectional area of signal line conductor (21a)) x (tensile strength of signal line conductor (21a)) + (cross-sectional area of signal line insulator (21b)) x (signal Tensile strength of wire insulator (21b))
The rigidity of the first power line unit (3) is expressed by the following formula for each of the plurality of first power lines (31) constituting the first power line unit (3): (31) is obtained by adding the stiffnesses of
(Rigidity of the first power supply line (31)) = (conductor cross-sectional area of the first conductor (31a)) x (tensile strength of the first conductor (31a)) + (cross-sectional area of the first insulator (31b)) x (Tensile strength of the first insulator (31b))
A composite cable (1) according to [1].

[3] The first power line unit (3) is configured by arranging 3 or more and 8 or less of the first power lines (31) along the cable circumferential direction, [1] or [ 2].

[4] The outer diameter (D1) of the twisted pair wire (2) is equal to or less than the length (D2) of the entire first power wire unit (3) in the facing direction of the second power wire, [1] A composite cable (1) according to any one of [3].

[5] The outer diameter of the twisted pair wire (2) is larger than the outer diameter of the first power wire (31) and the outer diameter of the second power wire (41) [1] to [4] A composite cable (1) according to any one of the preceding claims.

Although the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the scope of claims. Also, it should be noted that not all combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

1... Composite cable 2... Twisted pair wire (twisted wire)
21 Signal line 21a Signal line conductor 21b Signal line insulator 3 First power line unit 31 First power line 31a First conductor 31b First insulator 4 Second power line unit 41 Second Power supply line 41a Second conductor 41b Second insulator 5 Aggregate 6 Interposition 7 Pressing tape 8 Shield layer 9 Sheath 10 Drain wire

Claims (5)

A twisted wire in which multiple signal wires are twisted together;
a first power line unit in which a plurality of first power lines are arranged adjacent to each other in the cable circumferential direction;
a second power line unit having an even number of second power lines;
a sheath that collectively covers an assembly obtained by twisting the stranded wire, the plurality of first power wires, and the plurality of second power wires,
The twisted wire and the first power wire unit are arranged facing each other in the cable diameter direction,
The second power wire unit is configured such that an even number of the second power wires are arranged facing each other between the twisted wire and the first power wire unit in the cable circumferential direction. cage,
The rigidity of the first power wire unit is 1 to 1.5 times the rigidity of the stranded wire.
composite cable. the twisted wire is a twisted pair wire obtained by twisting a pair of the signal wires;
The signal line has a signal line conductor and a signal line insulator covering the signal line conductor,
the first power line has a first conductor and a first insulator surrounding the first conductor;
The rigidity of the twisted pair wire is obtained by adding together the rigidity of each of the signal wires represented by the following formula for the pair of signal wires constituting the twisted pair wire,
(Rigidity of signal line) = (conductor cross-sectional area of signal line conductor) x (tensile strength of signal line conductor) + (cross-sectional area of signal line insulator) x (tensile strength of signal line insulator)
The rigidity of the first power line unit is obtained by adding the rigidity of each of the first power lines represented by the following formula for the plurality of first power lines forming the first power line unit. is a
(Rigidity of first power supply wire) = (conductor cross-sectional area of first conductor) x (tensile strength of first conductor) + (cross-sectional area of first insulator) x (tensile strength of first insulator)
The composite cable of Claim 1. The first power line unit is configured by arranging three or more and eight or less first power lines along the cable circumferential direction.
A composite cable according to claim 1 or 2. The outer diameter D1 of the twisted pair wire is equal to or less than the length D2 of the entire first power wire unit in the facing direction of the second power wire.
The composite cable of Claim 2 .
The outer diameter D1 of the twisted pair wire is larger than the outer diameter of the first power wire and the outer diameter of the second power wire.
The composite cable of Claim 2 .

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