JP4760521B2 - Electrical cable disconnection detection device and disconnection detection method - Google Patents

Description

  The present invention relates to a disconnection detection device and a disconnection detection method for an electrical cable, and more particularly to an electrical cable disconnection detection device and a disconnection detection method that can reliably predict in advance a disconnection of an electrical shield layer of an electrical cable.

  With the electrification of automobiles, electric cables equipped with power supply lines and signal lines are being routed where they are subject to much vibration and bending of automobiles.

  A conventional electric cable includes a plurality of bundled electric wires such as a power supply line and a signal line, an electric shield layer that shields electromagnetic waves from the outside of the outer periphery, and a sheath that covers the outer periphery. The electric shield layer is formed of a metal wire braid formed by crossing a copper wire or a copper alloy wire with a tin-plated metal wire, or a metal tape such as aluminum.

  When a large amount of bending was applied to the electric cable, the metal element wire of the metal element braid was broken or the metal tape was broken in the electric shield layer. There is a risk that a broken metal element wire or a broken metal tape piece may penetrate and penetrate through an insulating layer such as a power supply line or a signal line. Therefore, in order to detect in advance the disconnection or breakage of the electrical shield layer, it has been studied to insert a disconnection detection line in the electrical shield layer.

In Patent Document 1, an enameled wire in which a thin insulating film is formed on a copper wire or a copper alloy wire is used as a disconnection detection line. Using an enameled wire that is more likely to break than a metal element wire or metal tape in the electrical shield layer, an electric current is passed through the enameled wire, and changes in current and resistance when the enameled wire is broken due to bending are detected to provide an electrical shield. Predicts disconnection of layers.
JP 2005-166450 A

  In the prior art of Patent Document 1, an enameled wire having an insulating film is used as a disconnection detecting wire. However, there is a fear that the enameled wire insulating film may be worn due to friction between the enameled wire and the surrounding metal wire due to bending motion. is there. In this case, there is a problem that disconnection cannot be reliably predicted when electrical continuity occurs between the surrounding metal wires.

  Accordingly, an object of the present invention is to provide an electrical cable disconnection detection device and a disconnection detection method capable of reliably detecting the disconnection of the electrical shield layer of the electrical cable.

  In order to achieve the above object, an electric cable disconnection detecting device according to the present invention is provided in an electric shield layer, an electric cable including a plurality of electric wires, an electric shield layer covering the plurality of electric wires, and a sheath covering the electric shield layer, and the electric shield layer. A disconnection detection line composed of a conductor line and an outer peripheral insulating layer, a voltage source electrically connected to the conductor line, a first detector electrically connected to the conductor line, and an electric shield layer electrically And a second detector connected to.

  In order to achieve the above object, an electric cable disconnection detecting device according to the present invention includes a plurality of electric wires, an electric shield layer covering the plurality of electric wires, an electric cable including a sheath covering the electric shield layer, and an electric shield layer. A disconnection detection line comprising a conductor line and an outer peripheral insulating layer, a voltage source electrically connected to the conductor line, and a detector electrically connected to the electric shield layer. It is what.

  In order to achieve the above object, the method for detecting disconnection of an electric cable according to the present invention includes a plurality of electric wires, an electric shield layer covering the plurality of electric wires, and an electric shield layer of the electric cable including a sheath covering the electric shield layer. A disconnection detection line composed of a wire and an outer peripheral insulating layer is provided, a voltage source is electrically connected to the conductor line, a voltage is applied, and a first detector is electrically connected to the conductor line to electrically The detection signal is detected, the second detector is electrically connected to the electric shield layer to detect the electric detection signal, and the electric signal is detected from the detection signal of the first detector and the detection signal of the second detector. The disconnection of the shield layer is determined.

  In order to achieve the above object, the method for detecting disconnection of an electric cable according to the present invention includes a plurality of electric wires, an electric shield layer covering the plurality of electric wires, and an electric shield layer of the electric cable including a sheath covering the electric shield layer. An electrical detection signal is provided by providing a disconnection detection line consisting of a wire and an insulating layer on its outer periphery, electrically connecting a voltage source to the conductor wire and applying a voltage, and electrically connecting a detector to the electrical shield layer And disconnection of the electric shield layer is determined from the detection signal of the detector.

  It is possible to realize a disconnection detection device and a disconnection detection method capable of reliably detecting the disconnection of the electric shield layer of the electric cable.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view of an electric cable used in the present invention. FIG. 2 is a cross-sectional view of the disconnection detection line used in the present invention. FIG. 3 is a schematic view showing an electric shield layer and a disconnection detection line. FIG. 4 is a configuration diagram of the disconnection detection device according to the first embodiment of the present invention.

  (Electric Cable) As shown in FIG. 1, an electric cable 10 includes seven electric wires 11 serving as power lines and signal lines, and an electric shield layer 12 for shielding electromagnetic waves from the outside provided on the outer periphery thereof. And a sheath 13 covering the outer periphery thereof. The electrical shield layer 12 is provided with a disconnection detection line 14.

  The seven electric wires 11 are bundled by twisting the six electric wires 11 around the electric wire 11 located at the center. Each electric wire 11 includes a conductor wire 15 and an insulating layer 16 on the outer periphery thereof.

  The electric shield layer 12 is a metal wire braid made by crossing a copper wire or a copper alloy wire with a tin-plated metal wire, a metal wire horizontal winding layer in which a metal wire is horizontally wound, or an aluminum tape. It is made of metal tape.

  The sheath 13 is made of a rubber material such as EPDM and a resin such as polyurethane, and has a substantially circular cross section.

  (Disconnection detection line) An enameled wire is preferably used as the disconnection detection line 14. As shown in FIG. 2A, the enameled wire is obtained by forming an insulating film (insulating layer) 18 made of various resins such as polyester around a conductor wire 17 such as a copper wire or a copper alloy wire. The insulating film 18 is formed with a thickness of about several μm to several hundred μm. As the enameled wire, a wire having a shorter bending life than the metal wire or metal tape forming the electric shield layer is used. The bending life can be set by the diameter and material of the conductor wire 17 of the enamel wire. For example, the diameter of the conductor wire 17 may be made larger than that of the metal strand forming the electric shield layer. Moreover, when the metal strand which forms an electrical shield layer consists of a copper wire, what is necessary is just to use the copper tin alloy wire whose intensity | strength is higher than a copper wire.

  As an example of another disconnection detection line, an insulated wire in which seven conductor wires 17 are twisted and an insulating layer 18 is formed around them as shown in FIG. 2B can be used. Each conductor wire 17 is formed by twisting a plurality of fine wires made of copper or copper alloy. The insulating layer 18 is made of polyvinyl chloride or fluororesin and has a circular cross section. The diameter, material, and twist pitch of the conductor wire 17 are set so that the bending life is shorter than that of the metal wire or metal tape forming the electric shield layer.

  Furthermore, an insulated wire in which an insulating layer 18 is formed on the outer periphery of a single conductor wire 17 as shown in FIG.

  As shown in FIG. 3, the disconnection detection line 14 is provided by being wound around the electric shield layer 12 along the longitudinal direction of the cable. In another embodiment, the disconnection detection line may be provided vertically on the electric shield layer. When the electric shield layer is made of a metal strand, the disconnection detection wire and the metal strand may be bundled or twisted together.

  (Disconnection Detection Device) A first embodiment of an electric cable disconnection detection device according to the present invention will be described with reference to FIG. Reference numeral 20 represents a disconnection detection line, 21 is a conductor line of the disconnection detection line, and 22 is an insulating layer of the disconnection detection line. Reference numeral 23 denotes an electric shield layer of the electric cable.

  One end of the conductor line 21 of the disconnection detection line 20 is electrically connected to the voltage source 24, and the other end is electrically connected to the ground via an ammeter as a first detector 25. On the other hand, the electric shield layer 23 of the electric cable is electrically connected to the ground via an ammeter as the second detector 26.

  The first detector 25 and the second detector 26 are electrically connected to a signal processing unit (not shown), and the detection signals of the first detector 25 and the second detector 26 are sent to the signal processing unit. It is done. The signal processing unit includes a program for processing the detection signal and determining the disconnection of the electric cable.

  As the first detector and the second detector, in addition to the ammeter for measuring the current flowing in the disconnection detection line and the electric shield layer, a resistor is connected in series with the disconnection detection line and the electric shield layer. You may use the voltmeter which measures the voltage of resistance. Moreover, you may use the resistance meter which measures the resistance value of a disconnection detection line or an electrical shield layer as a 1st detector and a 2nd detector.

  (Operation) A voltage is applied to the conductor line 21 of the disconnection detection line 20 by the voltage source 24, and a current flows through the conductor line 21. On the other hand, since the electric shield layer 23 is insulated by the conductor wire 21 and the insulating layer 22, no current flows. When no breakage occurs in the conductor wire 21 of the breakage detection line 20, the first detector 25 sends the current value A flowing through the conductor wire 21 to the signal processing unit as a detection signal, and the second detector 26 passes the current value. 0 is sent as a detection signal to the signal processing unit. The signal processing unit determines from the detection signal A of the first detector 25 and the detection signal 0 of the second detector 26 that the conductor wire 21 is in a normal state where no breakage has occurred.

  When many bending motions are applied to the electric cable, a breakage occurs in the conductor line 21 of the breakage detection line 20. Since the bending life of the disconnection detection line is set to be shorter than the bending life of the electrical shield layer, the disconnection detection line is disconnected before the electrical shield layer is disconnected. Reference numeral 27 denotes a disconnected portion.

  When a break occurs in the broken line 27 in the conductor line 21 of the break detection line 20, no current flows through the conductor line 21. Therefore, the first detector 25 sends a current value 0 as a detection signal to the signal processing unit, Since no current flows through the electrical shield layer 23, the second detector 26 sends the current value 0 as a detection signal to the signal processing unit. The signal processing unit determines from the detection signal 0 of the first detector 25 and the detection signal 0 of the second detector 26 that the conductor wire 21 is disconnected.

  When many bending motions are applied to the electric cable, the insulation layer 22 of the disconnection detection line is worn by friction between the disconnection detection line and the electric shield layer, and the conductor line 21 and the electric shield layer 23 of the disconnection detection line are electrically connected. It may become conductive. Reference numeral 28 denotes a worn portion.

  When electrical conduction occurs between the conductor wire 21 and the electrical shield layer 23 in the wear portion 28 in the insulating layer 22 of the disconnection detection wire 20, the current flowing through the conductor wire 21 changes from A to A ', and the first detection The device 25 sends the current value A ′ as a detection signal to the signal processing unit, and the second detector 26 causes the current of the current value B to flow due to the conduction of the electric shield layer. Send to. The signal processing unit determines from the detection signal A ′ of the first detector 25 and the detection signal B of the second detector 26 that the disconnection state has occurred due to wear.

  When it is determined that the signal processing unit is in a disconnected state, the signal processing unit issues a warning signal for predicting the disconnection. Based on the warning signal, the predetermined display device displays a disconnection warning to the person.

  (Operation) In the prior art, when electrical conduction occurs between the conductor line of the disconnection detection line and the electrical shield layer due to wear of the insulating layer of the disconnection detection line, the current flowing through the conductor line changes from A to A ′. When the current change is small, the signal processing unit cannot determine the disconnection state based on the detection signal A ′ of the first detector. Further, in this state, when a breakage occurs in the conductor line of the breakage detection line, a current A ″ flows through the conductor line through conduction by the wear portion 28 with the electrical shield layer, but the current change is minute. In some cases, the signal processing unit cannot determine the disconnection state based on the detection signal A ″ of the first detector.

  In this embodiment, when electrical conduction occurs between the conductor line of the disconnection detection line and the electrical shield layer due to wear of the insulating layer of the disconnection detection line, the current flowing through the conductor line changes from A to A ′ and The current flowing through the shield layer changes from 0 to B, and the signal processing unit determines the disconnection state based on the detection signal A ′ of the first detector and the detection signal B of the second detector. Therefore, even when the change in the current flowing through the conductor wire is very small, the disconnection state can be determined from the change in the current flowing through the electric shield layer.

  As described above, the disconnection detection device of the present embodiment is configured such that the conductor wire of the disconnection detection line is disconnected due to the bending movement of the electric cable and the conductor wire of the disconnection detection line is electrically shielded due to wear of the insulation layer of the disconnection detection line. Since the disconnection state can be determined in any case when the layer is electrically connected to the layer, the disconnection of the electric shield layer of the electric cable can be reliably detected.

(Embodiment 2)
FIG. 5 is a configuration diagram of a disconnection detection device according to the second embodiment of the present invention.

  (Electrical cable) Since the configuration of the electrical cable is not different from that of the first embodiment, the description thereof is omitted.

  (Disconnection detection line) The difference of the disconnection detection line used in this embodiment from the first embodiment is that the bending life of the disconnection detection line is set longer than the bending life of the electric shield layer. The bending life of the disconnection detection line is set according to the diameter and material of the conductor wire, the diameter of the strand forming the conductor wire, the twist pitch, and the like. For example, the diameter of the conductor wire 17 may be made smaller than that of the metal strand forming the electric shield layer.

  Further, the insulating layer of the disconnection detection line is set to be worn in a time shorter than the bending life of the electric shield layer. Thereby, before the electrical shield layer is disconnected due to the bending movement of the electrical cable, electrical conduction occurs between the conductor line of the disconnection detection line and the electrical shield layer. The wear time of the insulating layer is set according to the material and thickness of the insulating layer.

  Other configurations are not different from those of the first embodiment, and thus description thereof is omitted.

  (Disconnection Detection Device) A second embodiment of the electric cable disconnection detection device of the present invention will be described with reference to FIG. Reference numeral 30 denotes a disconnection detection line, 31 is a conductor line of the disconnection detection line, and 32 is an insulating layer of the disconnection detection line. Reference numeral 33 denotes an electric shield layer of the electric cable.

  One end of the conductor line 31 of the disconnection detection line 30 is electrically connected to the voltage source 34, and the other end is open. On the other hand, the electric shield layer 33 of the electric cable is electrically connected to the ground via an ammeter as the detector 36. The other end of the conductor line 31 of the disconnection detection line 30 may be electrically connected to the ground via a resistor.

  The detector 36 is electrically connected to a signal processing unit (not shown), and the detection signal of the detector 36 is sent to the signal processing unit. The signal processing unit includes a program for processing the detection signal and determining the disconnection of the electric cable.

  In addition to the ammeter that measures the current flowing through the electric shield layer, a voltmeter that connects a resistor in series with the electric shield layer and measures the voltage of the resistor may be used as the detector 36. Further, as the detector 36, an ohmmeter that measures the resistance value of the electric shield layer may be used.

  (Operation) A voltage is applied to the conductor line 31 of the disconnection detection line 30 by the voltage source 34. On the other hand, since the electric shield layer 33 is insulated by the conductor wire 31 and the insulating layer 32, no current flows. When electrical continuity is not generated between the conductor line 31 of the disconnection detection line 30 and the electrical shield layer, the detector 36 sends a current value 0 as a detection signal to the signal processing unit. The signal processing unit determines from the detection signal 0 of the detector 36 that the normal state where no disconnection has occurred.

  When a lot of bending motion is applied to the electric cable, the insulation layer 32 of the disconnection detection line is worn, whereby the conductor line 31 of the disconnection detection line and the electrical shield layer 33 are electrically connected. The break life of the disconnection detection line is set to be longer than the flex life of the electric shield layer, and the insulation layer of the disconnection detection line is set to wear out in a time shorter than the flex life of the electric shield layer. A short circuit between the conductor wire and the electric shield layer occurs before this occurs. Reference numeral 38 denotes a worn portion.

  When electrical conduction occurs between the conductor wire 31 and the electric shield layer 33 in the worn portion 38 of the insulating layer 32 of the disconnection detection line 30, a current C having a current value flows through the electric shield layer. A detection signal of value C is sent to the signal processing unit. The signal processing unit determines from the detection signal C of the detector 36 that the wire is disconnected due to wear.

  When it is determined that the signal processing unit is in a disconnected state, the signal processing unit issues a warning signal for predicting the disconnection. Based on the warning signal, the predetermined display device displays a disconnection warning to the person.

  (Effect) In this embodiment, when many bending motions are applied to the electric cable, before the disconnection occurs in the electric shield layer, the conductor of the disconnection detection line and the electric shield layer are worn due to wear of the insulating layer of the disconnection detection line. Will cause a short circuit. When a short circuit occurs between the conductor wire and the electrical shield layer, the current flowing through the electrical shield layer changes from 0 to C, and the signal processing unit determines the disconnection state based on the detection signal C of the detector. Therefore, it is possible to reliably detect disconnection of the electric shield layer of the electric cable.

  In addition, in the prior art, the disconnection cannot be detected unless the conductor of the disconnection detection line is completely disconnected, and there is some difference in the time until the conductor wire is completely disconnected. Even in this structure, there was some difference in the time for detecting disconnection. In this embodiment, since the disconnection is detected by the electrical conduction between the conductor wire and the electrical shield layer due to the abrasion of the insulating layer of the disconnection detection wire, it is not affected by the difference in time until the conductor wire is disconnected. Has an effect.

(Other variations)
The present invention is not limited to the electric cable of the above-described embodiment, but can be applied to the shape, size and number of electric wires such as power supply lines and signal lines, the arrangement of electric wires in the sheath, and the like designed according to the application purpose. .

  Further, the number of disconnection detection lines may be one, and preferably a plurality of disconnection detection lines may be provided.

(Application examples)
The disconnection detecting device and the disconnection detecting method of the present invention can be applied to an electric cable connected to a movable device of a robot or an automobile. In an automobile, for example, it can be applied to an electric cable to which vibration and bending are frequently applied, such as an electric brake harness and an in-wheel motor harness.

It is sectional drawing of the electric cable used for this invention. It is sectional drawing of the disconnection detection wire | line used for this invention, (a) is an enameled wire, (b) The insulated wire which twisted together the several conductor wire, (c) It is a figure of the insulated wire of the single conductor wire. It is a general-view figure which shows the electrical shield layer and disconnection detection line of this invention. It is a lineblock diagram of a disconnection detection device of an electric cable of a 1st embodiment of the present invention. It is a block diagram of the disconnection detection apparatus of the electric cable of the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electric cable 11 Electric wire 12, 23, 33 Electric shield layer 13 Sheath 14, 20, 30 Disconnection detection line 15 Electric wire conductor 16 Electric wire insulation layer 17, 21, 31 Conductor wire 18, 22, 32 Disconnection detection wire Insulating layer 24, 34 Voltage source 25 First detector 26 Second detector 27 Disconnection part 28, 38 Wear part 36 Detector

Claims (19)

An electric cable comprising a plurality of electric wires, an electric shield layer covering the plurality of electric wires, and a sheath covering the electric shield layer;
A disconnection detection line formed of a conductor wire and an insulating layer on the outer periphery thereof, provided in the electric shield layer;
A voltage source electrically connected to the conductor wire;
A first detector electrically connected to the conductor wire;
A second detector electrically connected to the electrical shield layer;
An apparatus for detecting disconnection of an electric cable, comprising:   2. The electric cable disconnection detection device according to claim 1, wherein a bending life of the disconnection detection line is set to be shorter than a bending life of the electric wire.   3. The electric cable disconnection detection device according to claim 2, wherein a bending life of the disconnection detection line is set according to a diameter or a material of the conductor wire. An electric cable comprising a plurality of electric wires, an electric shield layer covering the plurality of electric wires, and a sheath covering the electric shield layer;
A disconnection detection line formed of a conductor wire and an insulating layer on the outer periphery thereof, provided in the electric shield layer;
A voltage source electrically connected to the conductor wire;
A detector electrically connected to the electrical shield layer;
An apparatus for detecting disconnection of an electric cable, comprising:   The bending life of the disconnection detection line is set to be longer than the bending life of the wire, and the time until the insulating layer of the disconnection detection line is worn is set to be shorter than the bending life of the wire. The disconnection detecting device for an electric cable according to claim 4.   6. The electric cable disconnection detection device according to claim 5, wherein a bending life of the disconnection detection line is set according to a diameter or a material of the conductor wire.   7. The electric cable disconnection detection device according to claim 5, wherein a time until the insulating layer of the disconnection detection line is worn is set according to a material and a thickness of the insulating layer.   The disconnection detecting device for an electric cable according to any one of claims 1 to 7, wherein the disconnection detecting wire is an enameled wire in which an insulating film is formed on a conductor wire.   The electrical shield layer according to any one of claims 1 to 8, wherein the electrical shield layer is a metal strand braid knitted by intersecting metal strands or a metal strand horizontal winding layer obtained by horizontally winding a metal strand. Cable breakage detection device.   9. The electric cable break detection device according to claim 1, wherein the electric shield layer is a metal tape.   The said electric cable is an electric brake harness or an in-wheel motor harness, The disconnection detection apparatus of the electric cable in any one of Claims 1-10 characterized by the above-mentioned. A disconnection detection line comprising a conductor wire and an outer peripheral insulating layer is provided on the electric shield layer of the electric cable comprising a plurality of electric wires and an electric shield layer covering the plurality of electric wires and a sheath covering the electric shield layer;
Apply voltage by electrically connecting a voltage source to the conductor wire,
Electrically connecting a first detector to the conductor wire to detect an electrical detection signal;
Electrically connecting a second detector to the electrical shield layer to detect an electrical detection signal;
A method for detecting disconnection of an electrical cable, wherein the disconnection of the electrical shield layer is determined from the detection signal of the first detector and the detection signal of the second detector.   The method of claim 12, wherein the first detector detects a current value flowing through the conductor wire as the electrical detection signal.   The method of claim 12, wherein the first detector detects a resistance value of the conductor wire as the electrical detection signal.   15. The method for detecting disconnection of an electric cable according to claim 12, wherein the second detector detects a current value flowing through the electric shield layer as the electric detection signal.   15. The method for detecting disconnection of an electric cable according to claim 12, wherein the second detector detects a resistance value of the electric shield layer as the electric detection signal. A disconnection detection line comprising a conductor wire and an outer peripheral insulating layer is provided on the electric shield layer of the electric cable comprising a plurality of electric wires and an electric shield layer covering the plurality of electric wires and a sheath covering the electric shield layer;
Apply voltage by electrically connecting a voltage source to the conductor wire,
An electrical detection signal is detected by electrically connecting a detector to the electrical shield layer;
A method for detecting disconnection of an electric cable, wherein the disconnection of the electric shield layer is determined from a detection signal of the detector.   The method of claim 17, wherein the detector detects a value of a current flowing through the electrical shield layer as the electrical detection signal.   The method of claim 17, wherein the detector detects a resistance value of the electrical shield layer as the electrical detection signal.

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