JP2007026714A - Stretchable type power supply cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stretchable type power supply cable which is connected to a moving body and in which durability in carrying out stretching movement repeatedly is improved. <P>SOLUTION: A hollow protective tube 11 is formed in a cylindrical coil shape, and a core wire 12 in which a conductor 12a is covered by a covering material 12b is loosely inserted into the protective tube 11. A material with appropriate rigidity and flexibility is used for the protective tube 11. Especially, in a nitric acid atmosphere, the protective tube 11 and the covering material 12b are formed of a fluororesin. Moreover, when a stretchable type power supply cable 10 is used by hanging, a cable guide 14 to be loosely inserted into the inside of the coil-like cylinder of the protective tube 11 is installed for hanging at a part to fix the protective tube 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power supply cable for supplying power to an actuator such as a motor or a solenoid or providing an operation control signal. For example, in the case of a structure in which the actuator is incorporated in a moving body, the movement is accompanied. The present invention relates to a telescopic power supply cable that is required to expand and contract.

  For example, in an operation on an industrial robot or the like, since the robot hand needs to move between workpieces, a power supply robot cable for supplying power to an actuator for operating the robot hand is free to move as the robot hand moves. Property, particularly stretchability is required.

  By the way, a telescopic power supply cable is used in a reactor experimental apparatus. Control rods are used to control the operation of the nuclear reactor. However, in the experimental apparatus for nuclear reactors, safety plates are used instead of the control rods. FIG. 4 shows an outline of the structure of the safety plate driving device 1 used in the reactor experimental apparatus. The safety plate driving device 1 is disposed on the upper side of the experimental nuclear reactor 2, and the safety plate 3 is provided so as to appear and disappear at a predetermined position of the nuclear reactor 2. In the case of an emergency stop, the safety plate 3 is dropped into the nuclear reactor 2. For this reason, the safety plate 3 is attracted to and held by the electromagnet 4 at the upper end by a magnetic force, and the safety plate 3 is stopped by its own weight by stopping energization of the electromagnet 4 at the time of emergency stop of the nuclear reactor 2. 3 falls into the reactor 2. In order to energize the electromagnet 4, a telescopic power supply cable 5 is used. That is, when the safety plate 3 has fallen to the lowest position, the electromagnet 4 is lowered to adsorb the safety plate 3 and then the electromagnet 4 is raised so that the safety plate 3 can operate the nuclear reactor 2. Raise to position.

  The electromagnet 4 is raised and lowered by winding and unwinding the wire 6 suspending the electromagnet 4 around the wire drum 7. The wire 6 is guided by the guide wheel 8 in the tangential direction of the wire drum 7 from the vertical direction in which the electromagnet 4 is suspended. The feeding cable 5 is formed in a coil shape, and the wire 6 is inserted through the center of the coil shape. Therefore, the electromagnet 4 moves up and down by winding and unwinding the wire 6 with the wire drum 7, and the coiled power supply cable 5 expands and contracts accordingly.

  A cross section of a conventional feeding cable 5 is shown in FIG. Two conductors 5a for energizing the electromagnet 4 are covered with an inner layer 5b made of polyethylene resin, and the inner layer 5b is covered with an outer layer 5d made of urethane resin cored with paper 5c. It is as. In the power supply cable 5 with this structure, the inner and outer layers 5b and 5d have low rigidity, so when formed into a cylindrical coil shape, when contracted, only a part of the upper part is greatly expanded by its own weight, and the whole is lowered. turn into. In addition, since the electromagnet 4 must be lifted to the uppermost position by attracting the lowermost safety plate 3 with a magnetic force, the power supply cable 5 must expand and contract with a length that allows the electromagnet 4 to be raised and lowered. Although the amount of expansion / contraction depends on the scale of the experimental reactor 2, for example, it is about 200 mm when contracting and about 1600 mm when expanding, and a large one is required. For this reason, at the time of extension, it is in a state of being solidified and in close contact with the lower part and at the upper part of being extended. For this reason, the lower part is formed in the shape of a truncated cone having a diameter larger than that of the upper part, and the extension state in the upper part is suppressed as much as possible. In order to reduce the size of the safety plate drive device 1, the arrangement space of the power supply cable 5 cannot be increased, and thus there is a limit to increasing the coiled outer diameter.

  Also, as a robot cable, Patent Document 1 discloses a robot dither cable system in which the sheath of the cable is a quadrilateral cross section and the contact surface with the take-up machine is two faces of a square pole, and the friction between the cable and the take-up machine is increased. Is disclosed. Patent Document 2 discloses that in an optical composite power cable that sends power and optical signals to a moving body, a high-strength fiber bundle of polymer high-strength fiber is covered with resin and twisted at the center. An optical composite power cable is disclosed which is connected to a mobile body having a structure in which a rubber or plastic sheath is hung.

JP-A-9-267288 Japanese Patent Application Laid-Open No. 11-213779

  By the way, in the experimental nuclear reactor 2, liquid uranium is used as a fuel, which is a solution obtained by dissolving uranium in nitric acid. For this reason, the reactor 2 is in an atmosphere of nitric acid, and the nitric acid vaporized from the opening for entering and exiting the safety plate 3 into and from the reactor 2 may leak and may invade the safety plate driving device 1. The nitric acid leaking from the opening is prevented from flowing to the side where the electromagnet 4 is provided by scavenging with the purge air blown from the purge air supply pipe 9 disposed at the position facing the lower part of the pipe. However, the flow of nitric acid cannot be sufficiently blocked, and the power supply cable 5 may be exposed to a nitric acid atmosphere, and the outer layer 5d of the power supply cable 5 may be corroded in a short period of time.

  If the outer layer 5d of the power supply cable 5 is corroded, its elasticity will be lost, and the electromagnet 4 will not be able to move up and down reliably, so the safety plate 3 cannot be driven, and the experimental atoms This impedes the operation of the furnace 2 and impairs the continuity of the experiment. In addition, since the coiled outer diameter of the power supply cable 5 cannot be increased due to the restriction due to the arrangement space, when the rigidity of the outer layer 5d is reduced due to corrosion, the power supply cable 5 is deformed to come into contact with the wire 6 and during the expansion / contraction operation. The outer layer 5d rubs the wire 6, the outer layer 5d is peeled off, and the conductor 5a may be cut by the peeling of the outer layer 5d.

  On the other hand, the power supply cable disclosed in Patent Document 1 or Patent Document 2 is not formed in a coil shape, and is not used in a strongly acidic corrosive atmosphere such as a nitric acid atmosphere. There is a relatively large degree of freedom in the selection of materials such as covering materials.

  Therefore, the present invention has an appropriate size of rigidity, can reliably perform an expansion / contraction operation even with a large expansion / contraction amount, and does not increase the outer diameter even in a place where the arrangement space is limited. The object is to provide a telescopic power supply cable.

  As a technical means for achieving the above object, the telescopic power supply cable according to the invention of claim 1 can be expanded and contracted by being formed in a coil shape, and the core wire is held. In a telescopic power supply cable that electrically connects the conductors, a conductor is coated on a protective tube that is formed in a coil shape along the outer surface of the cylindrical shape and is extendable in the axial direction of the coil shape. The core wire covered with is inserted, and the core wire is slidable with respect to the protective tube.

  Since the protective tube formed in a coil shape expands and contracts in accordance with the movement of the moving body, the protective tube follows the moving body, and the core wire inserted through the protective tube also moves along with the expansion and contraction of the protective tube. Thus, an electrical connection state between the power source and the moving body can be maintained. Moreover, since the core wire slides with respect to the protective tube, the core wire is not twisted with respect to the protective tube, and a load is not applied to the core wire.

  The protective tube may be a material that can be formed into a coil shape and can be expanded and contracted, and may be a metal, a synthetic resin, or the like that has appropriate rigidity and flexibility.

  In addition, depending on the material of the protective tube, if the expanded state is maintained for a long time, the original shape at the time of contraction may not be restored even when contracted. When the protective tube having such a property is forcibly returned from the extended state to the contracted state, it is guided by the guide means and formed into a coil shape. Therefore, it is prevented that the state is inadvertently deformed in the contracted state. In particular, when the protective tube is suspended and expanded and contracted in the vertical direction, deformation is likely to occur because its own weight is applied during extension. Therefore, a guide means for guiding the protective tube may be provided in the suspension portion of the protective tube, and the guide means may be guided when the protective tube is contracted.

  The telescopic power supply cable according to the invention of claim 2 is characterized in that a material having temperature resistance and / or corrosion resistance is used for both the hollow tube and the covering material. .

  For example, the environmental atmosphere in the vicinity of a blast furnace or an incinerator is at a high temperature. On the other hand, in cold storage and low-temperature laboratories, the environment is at a low temperature. Therefore, a material having temperature resistance is used for both the hollow tube and the covering material. Further, in an environmental atmosphere of a corrosive gas such as a strong acid, a strong alkaline gas, or a halogen gas, a corrosion resistant material for the gas is used.

  The telescopic power supply cable according to the invention of claim 3 is suitable for use in an experimental nuclear reactor, and the hollow tube and the covering material have corrosion resistance to nitric acid. The material is used for a safety plate driving device of a nuclear reactor for experiments. Further, the telescopic power supply cable according to the invention of claim 4 is particularly suitable for the hollow tube and the covering material. It is characterized by using a fluororesin.

  Since liquid uranium is used in the experimental reactor, vaporized nitric acid exists in the environmental atmosphere. For this reason, a material having corrosion resistance to nitric acid is used. For example, there is a fluororesin such as tetrafluoroethylene resin (PTFE), and the fluororesin is used for the protective tube and the covering material. In addition, resistance in a nitric acid atmosphere can be provided.

  According to the telescopic power supply cable according to the present invention, even if the expansion and contraction is repeated, there is almost no fatigue, and the core wire is not inadvertently deformed, so the life can be extended.

  In addition, according to the telescopic power supply cable according to the third or fourth aspect of the present invention, the telescopic power supply cable can be used in a nitric acid atmosphere. Even if there is, it does not corrode.

  FIG. 1 shows a front view of a telescopic power supply cable according to the present invention. FIG. 2 is a cross-sectional view. The telescopic power supply cable 10 is configured such that a core wire 12 is accommodated in a hollow protective tube 11.

  The protective tube 11 is formed of a hollow tube, and the hollow tube is formed in a cylindrical coil shape. The core wire 12 is inserted into the protective tube 11. As shown in FIG. 2, the core wire 12 is formed by covering a conductor 12a with a covering material 12b. That is, the core wire 12 is slidably inserted into the protective tube 11 formed in a coil shape. Note that two core wires 12 are inserted to supply power to the electromagnet 4.

  FIG. 3 is a front view showing a state where the telescopic power supply cable 10 is suspended and used in an extended state. When the telescopic power supply cable 10 is suspended, the upper end portion is fixed to a non-moving portion of a desired device or the like. Then, as shown in the figure, a cable guide 14 as guide means is attached to the fixed portion. The cable guide 14 has an outer diameter that is loosely inserted into the inside of a cylinder formed in a coil shape of the protective tube 11, and is loosely inserted to an appropriate length above the protective tube 11 when contracted. . Further, the wire 6 for suspending the movable body that is fed by the telescopic power feeding cable 10 is provided through the cable guide 14. In addition, it is desirable that the wire 6 is disposed at a position that coincides with the axis of the coiled cylinder.

  The protective tube 11 is made of a material having appropriate rigidity and flexibility so that it can be expanded and contracted in a coiled state. Any material having such properties may be a metal or a synthetic resin. The inventor of the present application has developed it for use in the safety plate drive device 1 in an experimental reactor. As described above, the telescopic power supply cable of the safety plate drive device 1 is exposed to a nitric acid atmosphere. Therefore, a fluororesin is used for the protective tube 11 and the covering material 12b.

  When the telescopic power supply cable 10 is used in the safety plate driving device 1 of the experimental reactor 2, the power source and the electromagnet 4 as a moving body are connected via the telescopic power supply cable 10. That is, this telescopic power supply cable 10 is used in place of the conventional power supply cable 5. Further, the cable guide 14 is disposed at a portion where the protective tube 11 of the telescopic power supply cable 10 is fixed so as to be positioned inside the coiled cylinder of the telescopic power supply cable 10, and the cable guide 14 Is inserted, the wire 6 is arranged, and the electromagnet 4 is attached to the tip thereof. When the core wire 12 of the telescopic power supply cable 10 is connected to the electromagnet 4 and energized, the safety plate 3 can be adsorbed by a magnetic force. For this reason, the safety plate 3 is moved up and down by moving the electromagnet 4 up and down while the safety plate 3 is attracted to the electromagnet 4. Further, when the nuclear reactor 2 is stopped urgently, the energization to the electromagnet 4 is cut off to release the restraint by the magnetic force on the safety plate 3 and the safety plate 3 falls into the reactor 2 by its own weight. To do. In order to raise the safety plate 3 that has fallen to the lowest position, the electromagnet 4 is lowered to a position where the safety plate 3 is attracted by a magnetic force, the electromagnet 4 is energized to attract the safety plate 3 and the electromagnet 4 is raised. . At this time, the telescopic power supply cable 10 expands and contracts to maintain power supply to the electromagnet 4.

  That is, the telescopic power supply cable 10 expands when the electromagnet 4 is lowered, and contracts when the electromagnet 4 is raised. When contracting, the portion of the protective tube 11 positioned at the upper part of the coiled cylinder is guided by the cable guide 14, so that the telescopic power supply cable 10 contracts while maintaining its cylindrical shape. For this reason, even if the protective tube 11 is formed of a material that deforms when the load is continuously applied and maintained in the extended state, when the load is removed and contracted, the cable guide 14 Therefore, the original shape is corrected. Therefore, even if the installation space for the telescopic power supply cable 10 is limited, it can be securely stored in the installation space. Further, when returning to the original shape, the protective tube 11 is guided and contracted in a predetermined direction by the cable guide 14, so that the protective wire 11 is inserted into the wire 6 inserted along the coiled axis of the protective tube 11. The coiled inner surface of the tube 11 does not come into contact, and the protective tube 11 is not accidentally worn or damaged.

  Durability tests were conducted for the case where the telescopic power supply cable 10 was used in the safety plate driving device 1 of the experimental reactor 2. The test was carried out by separating the reactor 2 equipment and repeatedly applying a load in the range of shrinkage of 200 mm to 1600 mm. The protective tube 11 used in this test was made of a PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) tube having an inner diameter of 4 mm and an outer diameter of 6 mm so that the inner diameter was 50 mm in a cylindrical coil shape. It was assumed that it was wound at 29.5 ± 1. The protective tube 11 was coated with a coating material 12b made of ETFE (tetrafluoroethylene / ethylene copolymer) on a conductor 12a made of tin-plated oxygen-free annealed copper wire so that the outer diameter was 1.65 mm. The core wire 12 was inserted into the telescopic power supply cable 10. Two core wires 12 are inserted through the protective tube 11. The weight of the electromagnet 4 is 6 kg, and the weight corresponding to the safety plate 3 is 25 kg.

  Further, the expansion and contraction operation was repeated, and the protection tube 11, the core wire 12, and the energized state were confirmed every 100 times of the contraction operation. As a result, it was confirmed that there was no abnormality in the protective tube 11, the core wire 12, and the energized state even when the contraction operation was performed up to 500 times. Further, when the telescopic power supply cable 10 was maintained in an extended state for one week, the upper part of the protective tube 11 was partially bent downward and deformed. In this state, it was confirmed that when the telescopic power supply cable 10 was contracted, the protective tube 11 was guided by the cable guide 14 and contracted to restore the shape to a cylindrical shape. Then, when this contracted state was maintained for one week, it was confirmed that the original shape was restored. Further, after that, when the expansion / contraction operation was repeated 100 times, no abnormality occurred in any of the protective tube 11, the core wire 12, and the energized state.

  In this embodiment, since the extension power supply cable used in the safety plate driving device for the experimental reactor has been described, the material of the protective tube is a fluororesin resistant to a nitric acid atmosphere. Or a material having resistance to the environmental atmosphere (high temperature atmosphere, low temperature atmosphere, anticorrosive gas atmosphere, etc.) to which the coating material is exposed. For example, the protective tube may be a synthetic resin such as metal or vinyl chloride. Absent. In the embodiment, the case where the protective tube is required to expand and contract to a range of about 8 times the natural length in the range of 200 mm to 1600 mm has been described, but a material that expands and contracts according to the required range is used. be able to.

  Since the core wire slides with respect to the protective tube when the protective tube is extended and contracted because the core wire is loosely inserted into the extendable protective tube, the core wire operates regardless of the displacement of the protective tube. . For this reason, the core wire is not deformed and the protective tube is not rubbed, and there is no fatigue of the core wire. Therefore, it is suitable for electrical connection with a moving body such as an industrial robot having a large number of repetitions of expansion and contraction operations. In addition, by using a material resistant to a nitric acid atmosphere as a covering material for the protective tube and the core wire, it can be used for experimental nuclear reactor equipment and contribute to nuclear research.

It is a front view which shows schematic structure of the expansion-contraction type electric power cable which concerns on this invention. It is sectional drawing of the expansion-contraction type electric power feeding cable shown in FIG. The state which extended | stretched in the condition which suspends and uses the telescopic electric power feeding cable shown in FIG. 1 is shown. 1 is a front view showing a schematic structure of a safety plate driving device for an experimental nuclear reactor, which is a device suitable for mounting a telescopic power supply cable according to the present invention, in which a conventional telescopic power supply cable is mounted Is shown. It is sectional drawing of the conventional expansion-contraction type electric power feeding cable, and is a figure equivalent to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Safety plate drive device 2 Reactor 3 Safety plate 4 Electromagnet 5 Conventional power supply cable 6 Wire 7 Wire drum 8 Guide wheel 9 Purge air supply pipe
10 Telescopic power supply cable
11 Protection tube
12 core wire
12a conductor
12b Coating material
14 Cable guide (guide means)

Claims (4)

In a telescopic power supply cable that can be expanded and contracted by being formed in a coil shape, a core wire is held, and an electrical connection between the power source and the moving body is electrically connected by the core wire,
A hollow tube is formed in a coil shape along the outer surface of the cylindrical shape, and a core wire in which a conductor is covered with a covering material is inserted through a protective tube that is extendable in the axial direction of the coil shape,
A telescopic power supply cable, wherein the core wire is slidable with respect to the protective tube.   The telescopic power supply cable according to claim 1, wherein a material having temperature resistance and / or corrosion resistance is used for both the hollow tube and the covering material.   3. The expansion and contraction according to claim 2, wherein the hollow tube and the covering material are made of a material having corrosion resistance to nitric acid, and used for a safety plate driving device of an experimental nuclear reactor. Type power supply cable.   The telescopic power supply cable according to claim 3, wherein a fluororesin is used for the hollow tube and the covering material.

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