JP5192889B2 - Shield member abnormality detection method and shield member abnormality detection device - Google Patents

Description

  The present invention relates to a shield member abnormality detection method and a shield member abnormality detection device, and in particular, a conductive core wire, an internal insulator covering the core wire, a shield member wound around an outer periphery of the internal insulator, The present invention also relates to a shield member abnormality detection method and a shield member abnormality detection device for detecting an abnormality of the shield member in an electric wire having an external insulator covering the shield member.

  A CV cable 10 for supplying high-voltage power as shown in FIGS. 7 and 3 is known as the above-described electric wire. As shown in the figure, the CV cable 10 includes a core wire 11, an insulator 12 as an internal insulator, a copper tape 13 as a shield member, and a sheath 14 as an external insulator.

  The core wire 11 is made of a conductive conductor. The insulator 12 is made of crosslinked polyethylene or the like and covers the core wire 11. The copper tape 13 is provided to prevent noise from entering from the outside. The copper tape 13 is provided in a tape shape and is wound around the outer periphery of the insulator 12. The sheath 14 is made of polyethylene or the like and covers the copper tape 13.

  In the CV cable 10 described above, the copper tape 13 may be displaced due to laying conditions or secular changes. This misalignment may cause a portion of the core wire 11 that is not covered by the copper tape 13 depending on the location. Thereby, there existed a problem that the performance quality of the CV cable 10 deteriorated.

  Conventionally, methods using X-ray imaging have been proposed to detect the displacement of the copper tape 13 (for example, Patent Documents 1 to 4). However, an apparatus capable of X-ray imaging has a problem that the apparatus itself is large and expensive, and qualification is required for imaging, so that versatility is low.

  Therefore, the present applicant has proposed an abnormality detection device for a shield member as shown in FIGS. 7 and 3 (Patent Documents 5 and 6). First, the abnormality detection apparatus shown in FIG. 7 will be described. As shown in the figure, the abnormality detection device has a structure in which the CV cable 10 is sandwiched between the transmission antenna AT11 and the reception antenna AT12, and the copper tape 13 Detection of misalignment. As shown in FIG. 7A, when the copper tape 13 is present, most of the radio waves transmitted from the transmission antenna AT11 are reflected by the copper tape 13, so that the reception level at the reception antenna AT12 becomes low. On the other hand, as shown in FIG. 7B, when there is no copper tape 13, the radio wave transmitted from the transmitting antenna AT11 is reflected only by the core wire 11, so that the receiving antenna AT12 is compared with the case where the copper tape 13 is present. The reception level increases. The deviation of the copper tape 13 inside the CV cable 10 is detected based on this reception level difference.

  Next, the abnormality detection apparatus shown in FIG. 3 will be described. As shown in the figure, the abnormality detection apparatus includes a reflection unit 31 in addition to the structure in which the CV cable 10 is sandwiched between the transmission antenna AT11 and the reception antenna AT12. By providing the reflection unit 31, the reception antenna AT12 receives a direct wave W1 that is a radio wave directly reaching the reception antenna AT12 from the transmission antenna AT11, and a reflected wave reaching the reception antenna AT12 after being reflected by the reflection unit 31 from the transmission antenna AT11. W2 is received. As shown in FIGS. 3A and 3B, the reflected wave W2 has a different path length with and without the copper tape 13, and as a result, the intensity of the interference wave between the direct wave W1 and the reflected wave W2 is different. Different.

  Therefore, by adjusting the position of the reflecting portion 31, the reception level of the interference wave between the reflected wave W2 and the direct wave W1 when the copper tape 13 is present is weakened, and directly with the reflected wave W2 when the copper tape 13 is not present. The path length of the reflected wave W2 is adjusted so that the reception level of the interference wave with the wave W1 is increased. Thereby, the difference in the reception level of the radio wave at the reception antenna AT12 depending on the presence or absence of the copper tape 13 can be further increased.

  As a method for determining the presence / absence of the copper tape 13 from the reception level that varies depending on the presence / absence of the copper tape 13 described above, the following method can be considered. That is, when the reception level of the reception antenna AT12 exceeds the threshold value, it is determined that there is no copper tape 13 and the copper tape 13 is displaced, and the copper tape 13 is present while the copper tape 13 is below the threshold value. It is determined that no deviation has occurred. However, the reception level difference described above becomes smaller as the shift width of the copper tape 13 becomes smaller.

  The present inventor, for example, uses the abnormality detection device shown in FIG. 3 to each of the CV cables 10 in which the deviation of the copper tape 13 having a deviation width of 50 mm, a deviation width of 10 mm, and a deviation width of 0 mm (normal) occurs in the longitudinal direction. The reception level was measured by scanning. The CV cable 10 has a length of about 1.5 m, and the center copper tape 13 is shifted. The results are shown in FIG. As shown in the figure, it can be seen that peaks and valleys appear alternately in the reception level according to the scanning of the CV cable 10.

Further, as shown in FIG. 5A, when the deviation width is 50 mm, the maximum reception level of the normal part where the deviation of the copper tape 13 does not occur and the maximum reception of the deviation part where the deviation of the copper tape 13 occurs. There is a difference of about 8 dB from the level. Even when the maximum reception level of the shift portion with the shift width of 50 mm is compared with the maximum reception level with the shift width of 0 mm (normal) shown in FIG. On the other hand, as shown in FIG. 5B, there is a difference of only about 2 dB between the maximum reception level of the deviation portion having a deviation width of 10 mm and the maximum reception level of the normal portion. That is, in the conventional determination of the shift portion based on the threshold value, a large shift portion having a shift width of about 50 mm can be detected, but it is difficult to detect a shift portion having a small shift width of 10 mm.
Japanese Patent Publication No. 6-81396 Japanese Patent Publication No. 8-21468 JP-A-6-207826 Japanese Patent Laid-Open No. 5-26648 Japanese Patent Application No. 2006-254559 Japanese Patent Application No. 2007-200583

  Therefore, the present invention focuses on the above-described problems, and an object of the present invention is to provide an abnormality detection device that can accurately detect even a small shift portion.

The invention according to claim 1, which has been made to solve the above-mentioned problems, includes a conductive core wire, an internal insulator covering the core wire, a shield member wound around an outer periphery of the internal insulator, and the shield member In an abnormality detection method for a shield member for detecting an abnormality of the shield member in an electric wire having an external insulator covering the antenna, a step of arranging a transmission antenna and a reception antenna so as to sandwich the electric wire, and a radio wave to the transmission antenna A step of transmitting, a step of causing the reception antenna to receive a radio wave transmitted by the transmission antenna, and a maximum reception level of the reception antenna within a scanning range along a longitudinal direction of the electric wire of the transmission antenna and the reception antenna. storing the value and the minimum value, and calculating their reception level difference, the reception level difference to the calculated's And detecting an abnormality of the shield member when the above determination value resides in the abnormality detecting method of the shield member, characterized in that sequentially performed.

  The invention according to claim 2 includes a conductive core wire, an internal insulator that covers the core wire, a shield member that is wound around an outer periphery of the internal insulator, and an external insulator that covers the shield member. In the shield member abnormality detection method for detecting an abnormality of the shield member in an electric wire, a transmission antenna and a reception antenna constituting each of a pair of transmission / reception units are arranged so as to sandwich the electric wire, and the pair of transmission / reception units are mutually connected. A step of being arranged so as to be separated in the longitudinal direction of the electric wire by a distance between a reception level peak at a gap portion of the shield member obtained in advance and a reception level trough appearing before or after a predetermined number of the peaks; and the transmission Transmitting the radio wave to the antenna, receiving the radio wave transmitted by the transmitting antenna to the receiving antenna, and the pair of It consists in the abnormality detecting method of the shield member, which comprises carrying out the steps of detecting an abnormality of the shield member on the basis of a difference between one of the reception level and the other of the reception level of signal units, sequentially.

The invention according to claim 3 has a conductive core wire, an internal insulator covering the core wire, a shield member wound around the outer periphery of the internal insulator, and an external insulator covering the shield member. In the abnormality detection device for a shield member that detects an abnormality of the shield member in an electric wire, the transmission antenna is a reception antenna disposed so as to sandwich the electric wire between a transmission antenna that transmits radio waves and the transmission antenna. Storing the reception antenna that receives the radio wave transmitted from, and the maximum value and the minimum value of the reception level of the reception antenna within a scanning range along the longitudinal direction of the wire of the transmission antenna and the reception antenna ; calculation means for calculating their reception level difference, the reception level difference to the calculated of the shield member when the above displacement determination value Abnormality detecting means for detecting the atmospheric resides in the abnormality detecting apparatus of the shield member comprising the.

  The invention according to claim 4 includes a conductive core wire, an internal insulator covering the core wire, a shield member wound around an outer periphery of the internal insulator, and an external insulator covering the shield member. In the abnormality detection device for a shield member that detects an abnormality of the shield member in an electric wire, a transmission antenna that transmits radio waves, and a reception antenna that is disposed so as to sandwich the electric wire between the transmission antenna and the transmission A pair of transmission / reception units each configured of a reception antenna that receives radio waves transmitted from the antenna; a reception level received by one of the reception antennas of the pair of transmission / reception units; and a reception level received by the other reception antenna An abnormality detecting means for detecting an abnormality of the shield member based on a difference between the pair of transmission / reception units. Is provided so as to be separated in the longitudinal direction of the electric wire by the distance between the peak of the reception level at the deviation portion of the shield member obtained in advance and the valley of the reception level appearing before or after the predetermined number of the peak. It exists in the abnormality detection apparatus of the shield member characterized by the above-mentioned.

  As described above, according to the first and third aspects of the invention, by detecting an abnormality of the shield member based on the reception level difference between the maximum value and the minimum value of the reception level within the scanning range, a small deviation portion can be obtained. It can be detected accurately.

  According to the second and fourth aspects of the present invention, when one of the pair of transmission / reception units is located in the shift portion, the reception level received by one reception antenna and the reception level received by the other antenna of the pair of transmission / reception units. Since the difference can be increased, even a small misalignment can be detected accurately.

First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a first embodiment of an abnormality detection device 20 for a shield member according to the present invention. The abnormality detection device 20 detects an abnormality of the copper tape 13 of the CV cable 10, for example. Here, the abnormality of the copper tape 13 means that the copper tape 13 is misaligned and a misalignment portion that is not covered by the copper tape 13 is generated in a part of the core wire 11.

  As described in the background art, the CV cable 10 includes a core wire 11, an insulator 12 as an internal insulator, a copper tape 13 as a shield member, and a sheath 14 as an external insulator. . The core wire 11 is made of a conductive conductor. The insulator 12 is made of crosslinked polyethylene or the like and covers the core wire 11. The copper tape 13 is provided in a tape shape and is wound around the outer periphery of the insulator 12. The sheath 14 is made of polyethylene or the like and covers the copper tape 13.

  The abnormality detection device 20 includes a shield case 30, a transmission unit 40, a reception unit 50, a microcomputer (hereinafter referred to as μCOM) 60, and an alarm unit 70. The box-shaped shield case 30 is formed of a conductor that reflects radio waves. The shield case 30 is provided with a pair of through holes (not shown) through which the CV cable 10 passes. The transmission antenna AT11 and the reception antenna AT12 are accommodated in the shield case 30 so that the CV cable 10 is sandwiched between the transmission antenna AT11 and the reception antenna AT12 when the CV cable 10 is passed through the through hole of the shield case 30. In the shield case 30, a portion where the transmitting antenna AT 11 and the receiving antenna AT 12 are arranged on the side Y 1 in the direction Y 1 sandwiching the CV cable 10 and the direction Y 2 orthogonal to the longitudinal direction of the CV cable 10 is referred to as a reflecting portion 31. The reflector 31 is provided so as to be orthogonal to the direction Y2.

  The transmitting unit 40 includes an oscillation circuit 41 that outputs an oscillation signal having a predetermined frequency, an amplifier 42 that amplifies the oscillation signal, a transmission antenna AT11 that receives the amplified oscillation signal and transmits radio waves having a predetermined frequency, It has. The transmission antenna AT11 transmits a horizontal radio wave to the CV cable 10. Specifically, as shown in FIG. 2, the transmission antenna AT11 is provided so as to generate radio waves such that the direction in which the electric field component of the radio waves is generated and the CV cable 10 are horizontal. On the contrary, the generation direction of the magnetic field component of the radio wave is perpendicular to the CV cable 10.

  The receiving unit 50 includes a receiving antenna AT12 that receives radio waves of a predetermined frequency, and a receiving circuit 51 that demodulates radio waves received by the receiving antenna AT12 and outputs a reception level signal corresponding to the reception level to the μCOM 60. I have. The μCOM 60 includes a central processing unit (hereinafter referred to as “CPU”) 61 that performs various processes according to a processing program, a ROM 62 that is a read-only memory storing a program for processing performed by the CPU 61, and various processing steps in the CPU 61. It has a RAM 63 that is a readable / writable memory having a work area to be used, a data storage area for storing various data, and the like, and these are connected by a bus line. The alarm unit 70 is composed of a speaker, a display, and the like controlled by the μCOM 60, and generates an alarm indicating that a deviation portion of the CV cable 10 has been detected.

  In the abnormality detection device 20 having the above-described configuration, a difference occurs in the reception level of the reception antenna AT12 when the copper tape 13 is present (when normal) and when there is no copper tape (when abnormal). What is considered as one of the principles will be described below with reference to FIG. FIG. 3A is an image diagram showing radio waves reaching the receiving antenna AT12 from the transmitting antenna AT11 when the copper tape 13 is present. FIG. 3B is an image diagram showing radio waves reaching the receiving antenna AT12 from the transmitting antenna AT11 when the copper tape 13 is not present. In FIG. 3, arrows indicate the progress of radio waves. A solid line indicates a direct wave W1 that is a radio wave that directly reaches the reception antenna AT12 from the transmission antenna AT11, and a dotted line indicates a reflected wave W2 that reaches the reception antenna AT12 after being reflected from the transmission antenna AT11 by the reflection unit 31.

  As shown in FIG. 3A, when the CV cable 10 has the copper tape 13, most of the radio waves from the transmission antenna AT11 are blocked by the copper tape 13 having a large diameter. On the other hand, as shown in FIG. 3B, when there is no copper tape 13 in the CV cable 10, only the core wire 11 having a small diameter blocks the radio wave from the transmission antenna AT11, and almost no radio wave from the transmission antenna AT11. It reaches the receiving antenna AT12 without being blocked.

  Since the insulator 12 between the copper tape 13 and the core wire 11 is about 4 to 5 mm regardless of the thickness of the CV cable 10, the shielding effect when the copper tape 13 is present is enhanced. Therefore, when the copper tape 13 is not present, the reception level of the direct wave W1 at the reception antenna AT12 is higher than when the copper tape 13 is present.

  Further, as shown in FIGS. 3A and 3B, the transmission antenna AT11 and the reception antenna AT12 are provided in the shield case 30, so that the reception antenna AT12 reflects the direct wave W1 and the reflection antenna from the transmission antenna AT11. The interference wave with the reflected wave W2 reaching the receiving antenna AT12 after being reflected at 31 is received. As shown in FIG. 3A, when the copper tape 13 is present, the reflected wave W2 is reflected in the order of the copper tape 13 → the reflective portion 31 → the copper tape 13, or the copper tape 13 → the reflective portion 31. Are received by the receiving antenna AT12 through the path of reflection in this order. On the other hand, as shown in FIG. 3B, when there is no copper tape 13, the reflected wave W2 is reflected in the order of the core wire 11 → reflecting portion 31 → the core wire 11, or the core wire 11 → the reflecting portion 31. The signal is received by the receiving antenna AT12 through a path that is reflected in order. Since the thickness of the insulator 12 is about 4 to 5 mm, as is clear from the above, the path length of the reflected wave W2 is different between when the copper tape 13 is present and when the copper tape 13 is not present, and as a result, the intensity of the interference wave is different.

  Therefore, the shape of the shield case 30 is adjusted to adjust the path length of the reflected wave W2. That is, the reception level of the interference wave between the reflected wave W2 and the direct wave W1 when the copper tape 13 is present is weakened, and the reception level of the interference wave between the reflected wave W2 and the direct wave W1 when there is no copper tape 13 is The path length of the reflected wave W2 is adjusted so as to increase. Thereby, the difference in the reception level of the radio wave at the reception antenna AT12 depending on the presence or absence of the copper tape 13 can be further increased.

  The inventor, for example, uses the abnormality detection apparatus shown in FIG. 1 to each of the CV cables 10 in which the deviation of the copper tape 13 having a deviation width of 50 mm, a deviation width of 10 mm, and a deviation width of 0 mm (normal) occurs in the longitudinal direction. The reception level was measured by scanning. The CV cable 10 has a length of about 1.5 m, and the center copper tape 13 is shifted. The results are shown in FIG. As shown in the figure, it can be seen that the reception level repeatedly fluctuates up and down according to the scanning of the CV cable 10. The reason why this fluctuation occurs is that the radio wave emitted toward the CV cable 10 reflects a path reflected on the shift end surface of the copper tape 13, the conductor 11 of the CV cable 10, and the end surface of the copper tape 13 in the longitudinal direction. It is considered that there is something that passes through and reaches the receiving antenna AT12. Since the length of this path varies according to scanning, it is considered that the reception level of the reception antenna AT12 varies regardless of the presence or absence of the copper tape 13.

  As shown in FIG. 4, the reception level difference between the point Pmax at which the reception level is maximum and the point Pmin at which the reception level is minimum is 16 dB when the deviation width is 50 mm, 10 dB when the deviation width is 10 mm, and the deviation width is 0 mm ( In the case of normal), it was found to be 4 dB. Therefore, for example, if the difference between the reception level at the point Pmax (maximum reception level) and the reception level at the point Pmin (minimum reception level) is 7 dB or more, it is determined that there is a deviation. Thus, it is possible to detect a deviation with a deviation width of 10 mm with a margin of 3 dB.

  The detailed operation of the abnormality detection apparatus shown in FIG. 1 described above will be described below with reference to FIG. First, the operator passes the CV cable 10 through a through hole (not shown) of the shield case 30 described above. Thereby, as shown in FIG. 1, the transmission antenna AT11 and the reception antenna AT12 are arranged so as to sandwich the CV cable 10. Thereafter, the operator turns on the power of the abnormality detection device 20 and scans the abnormality detection device 20 along the longitudinal direction of the CV cable 10. In response to the power-on, the CPU 61 in the abnormality detection device 20 oscillates the transmission circuit 41 of the transmission unit 40 (step S1). Thereby, a radio wave is transmitted from the transmission antenna AT11. When a radio wave is transmitted from the transmission antenna AT11, the reception antenna AT12 receives the radio wave. The reception circuit 51 outputs a reception level X obtained by demodulating the radio wave received by the reception antenna AT12 to the CPU 61.

  After the reception level X is input (step S2), the CPU 61 determines that the reception level X input in step S2 is the maximum reception level Xmax, if it is the first reception level X input after power-on (Y in step S3). After the minimum reception level Xmin is stored in the RAM 63 (step S4), the process proceeds to step S9. On the other hand, if the reception level X is input for the second time and thereafter (N in step S3), the CPU 61 inputs it if the reception level X input in step S2 is larger than the maximum reception level Xmax (Y in step S5). After the reception level X is stored in the RAM 63 as the maximum reception level Xmax (step S6), the process proceeds to step S9. In addition, if the reception level X input after the second time is smaller than the minimum reception level Xmin (N in step S5 and Y in step S7), the CPU 61 sets the input reception level X as the minimum reception level Xmin in the RAM 63. (Step S8), the process proceeds to step S9.

  At the time of proceeding to step S9, the maximum value of the reception level within the scanned range is stored in the RAM 63 as the maximum reception level Xmax and the minimum value of the reception level is stored as the minimum reception level Xmin. Next, the CPU 61 calculates a difference Y between the minimum reception level Xmin and the maximum reception level Xmax (step S9). Then, the CPU 61 functions as an abnormality detection means, and if the calculated difference Y is equal to or larger than the deviation determination value Z (for example, 7 dB) (Y in step S10), an alarm that detects the deviation of the copper tape 13 and notifies that fact. Is output from the alarm unit 70 (step S11), and the process is terminated. On the other hand, if the calculated difference Y is less than the deviation determination value Z (N in step S11), the CPU 61 determines that it is normal and proceeds to step S12. When the operator inputs that the scanning of the CV cable 10 is finished using an operation button (not shown), the CPU 61 determines that the operation of the CV cable 10 is finished (Y in step S12), and the above steps S1 to S10 are performed. The repetition of the operation is terminated.

  As shown in FIG. 4, when the deviation width of the copper tape 13 is 10 mm, the difference between the maximum reception level of the normal part and the maximum reception level of the deviation part is only about 2 dB. It has been difficult to detect a small shift portion of 10 mm by the shift detection by comparison. On the other hand, according to the first embodiment described above, the displacement detection of the copper tape 13 is performed by comparing the reception level difference between the maximum reception level Xmax and the minimum reception level Xmin and the displacement determination value. Since the reception level difference between the maximum reception level Xmax and the minimum reception level Xmin is 4 dB even when the deviation width is 10 mm, a small deviation portion of about 10 mm, which has not been possible in the past, can be accurately detected.

  In the first embodiment described above, the transmission antenna AT11 and the reception antenna AT12 are covered with the shield case 30, but the present invention is not limited to this. For example, the reflector may be provided only on the Y2 side of the electric wire, or the shield case 30 may not be provided as shown in FIG.

  Further, in the first embodiment described above, every time the oscillation circuit 41 is driven to oscillate, based on the reception level difference between the maximum value of the reception level and the minimum value of the reception level in the scanning range of the CV cable 10 until then. Although the abnormality of the shield member has been detected, the present invention is not limited to this. For example, the abnormality of the shield member may be detected based on the reception level difference between the maximum value of the reception level and the minimum value of the reception level in the entire scanning range of the CV cable 10. Further, every time the CV cable 10 is scanned for a certain distance, a reception level difference between the maximum value of the reception level and the minimum value of the reception level within the certain distance range is calculated, and the shield member is calculated based on the calculated reception level difference. The abnormality may be detected.

Second Embodiment In the first embodiment described above, the maximum reception level Xmax and the minimum reception level Xmin are detected based on the change in the reception level from the reception antenna AT12, and the reception level difference Y is obtained. However, the present invention is not limited to this. For example, as shown in FIG. 7, it is conceivable to detect the reception level difference Y by using two transmission antennas AT11 and AT12.

  Next, 2nd Embodiment of this invention is described based on drawing. FIG. 6 is a block diagram showing a second embodiment of the shield member abnormality detection device 20 of the present invention. In the figure, the same parts as those of the abnormality detection apparatus 20 shown in FIG. 1 already described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. As shown in FIG. 7, the abnormality detection device 20 includes a pair of transmission / reception units 81 and 82 arranged side by side along the longitudinal direction of the CV cable 10. Each of the transmission / reception units 81 includes an oscillation circuit 41, an amplifier 42, a transmission antenna AT11, a reception antenna AT12, and a reception circuit 51. The shield case is provided with a partition wall so that the radio waves of the transmission / reception unit do not affect each other.

Hereinafter, before explaining the configuration of the second embodiment, the principle of detection of the shift portion of the second embodiment will be described below with reference to FIG. As shown in the figure, the reception level shows that peaks and valleys appear alternately depending on the position of the CV cable 10. In FIG. 4 (B), Pmax is a peak of the reception level (= maximum reception level) at a deviation part having a deviation width of 10 mm, Pmin is a valley of reception level appearing immediately before Pmax (= minimum reception level), P ₁ is a trough of a reception level appearing two times before Pmax, P ₂ is a trough of a reception level appearing immediately after Pmax, and P ₃ is a trough of a reception level appearing two times after Pmax. In the case of this experiment, the interval between the peak and the valley (between Pmax and Pmin in FIG. 4B) is about 30 mm (however, this interval is different in the vicinity of the shift portion. Pmax in FIG. 4B). between the P ₁ and 40 mm). Therefore, the transmission / reception units 81 and 82 are arranged 30 mm apart from each other so that the transmission / reception unit 81 can detect the reception level of Pmax and the transmission / reception unit 82 can detect the reception level of Pmin. If the difference in the reception level of 82 is obtained, the difference in reception level becomes large when the transmission / reception unit 82 reaches Pmax, and a shift portion can be detected.

However, since the transmission antenna AT11 and the reception antenna AT12 used in this experiment are 2.45 GHz band and the size thereof is 60 mm ² , it is impossible to arrange the transmission / reception units 81 and 82 at intervals of 30 mm. is there. Therefore, when using transmit antennas AT11 and AT12, as described above, detects the reception level Pmax by the transmission and reception unit 81, so as to detect a reception level of P ₁ by the transmission and reception unit 82, a transceiver unit 81, 82 to each other 90 mm (Pmax and the distance between P ₁₎ may be disposed spaced apart to. In this case, the minimum of the troughs of the reception level cannot be obtained, but a sufficiently large reception level difference can be obtained as compared with the normal case.

  Further, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

It is a block diagram which shows 1st Embodiment of the abnormality detection apparatus which implemented the abnormality detection method of the shield member of this invention. It is a figure which shows the relationship between an electromagnetic wave and a CV cable. (A) is an image figure which shows the electromagnetic wave which reaches | attains a receiving antenna from a transmitting antenna when there is a copper tape, (B) is an image figure which shows the electromagnetic wave which reaches | attains a receiving antenna from a transmitting antenna when there is no copper tape. (A) to (C) are each a CV cable having a displacement width of 50 mm, a displacement width of 10 mm, and a displacement width of 0 mm (normal) using the abnormality detection apparatus shown in FIG. The result of scanning and measuring the reception level is shown. It is a flowchart which shows the process sequence of CPU which comprises the abnormality detection apparatus shown in FIG. It is a block diagram which shows 2nd Embodiment of the abnormality detection apparatus which implemented the abnormality detection method of the shield member of this invention. It is an example of the abnormality detection apparatus of the shield member which the present applicant previously proposed.

Explanation of symbols

10 CV cable (electric wire)
11 Core wire 12 Insulator (Internal insulator)
13 Copper tape (shield member)
14 Sheath (external insulator)
20 Abnormality detection device 61 CPU (abnormality detection means)
81, 82 Transmission / reception unit AT11 Transmission antenna AT12 Reception antenna

Claims (4)

An abnormality of the shield member in an electric wire having a conductive core wire, an internal insulator covering the core wire, a shield member wound around an outer periphery of the internal insulator, and an external insulator covering the shield member In the method of detecting an abnormality of the shield member to be detected,
Arranging a transmitting antenna and a receiving antenna so as to sandwich the electric wire;
Transmitting radio waves to the transmitting antenna;
Receiving the radio wave transmitted by the transmitting antenna at the receiving antenna;
Storing a maximum value and a minimum value of the reception level of the reception antenna within a scanning range along a longitudinal direction of the electric wire of the transmission antenna and the reception antenna, and calculating a difference between the reception levels;
Detecting the abnormality of the shield member when the calculated reception level difference is greater than or equal to a deviation determination value ;
A method for detecting an abnormality of a shield member, characterized in that the steps are sequentially performed. An abnormality of the shield member in an electric wire having a conductive core wire, an internal insulator covering the core wire, a shield member wound around an outer periphery of the internal insulator, and an external insulator covering the shield member In the method of detecting an abnormality of the shield member to be detected,
A transmission antenna and a reception antenna constituting each of the pair of transmission / reception units are arranged so as to sandwich the electric wire, and the pair of transmission / reception units obtain a reception level peak at a gap portion of the shield member obtained in advance from each other and A step of being arranged so as to be separated in the longitudinal direction of the electric wire by a distance from a trough of a reception level appearing before or after a predetermined number;
Transmitting radio waves to the transmitting antenna;
Receiving the radio wave transmitted by the transmitting antenna at the receiving antenna;
Detecting an abnormality of the shield member based on a difference between one reception level of the pair of transmission units and the other reception level;
A method for detecting an abnormality of a shield member, characterized in that the steps are sequentially performed. An abnormality of the shield member in an electric wire having a conductive core wire, an internal insulator covering the core wire, a shield member wound around an outer periphery of the internal insulator, and an external insulator covering the shield member In the abnormality detection device for the shield member to be detected,
A transmitting antenna that transmits radio waves,
A receiving antenna disposed so as to sandwich the electric wire between the transmitting antenna and a receiving antenna for receiving the radio wave transmitted from the transmitting antenna;
Storing a maximum value and a minimum value of a reception level of the reception antenna within a scanning range along a longitudinal direction of the electric wire of the transmission antenna and the reception antenna, and calculating means for calculating a difference between the reception levels;
An abnormality detection means for detecting an abnormality of the shield member when the calculated reception level difference is equal to or greater than a deviation determination value ;
An apparatus for detecting an abnormality of a shield member, comprising: An abnormality of the shield member in an electric wire having a conductive core wire, an internal insulator covering the core wire, a shield member wound around an outer periphery of the internal insulator, and an external insulator covering the shield member In the abnormality detection device for the shield member to be detected,
A pair of transmission antennas that transmit radio waves, and a reception antenna that is disposed so as to sandwich the electric wire between the transmission antennas and that receives radio waves transmitted from the transmission antenna, respectively. A transmission / reception unit of
An abnormality detection means for detecting an abnormality of the shield member based on a difference between a reception level received by one of the reception antennas of the pair of transmission / reception units and a reception level received by the other reception antenna;
The pair of transmission / reception units are separated in the longitudinal direction of the electric wire by a distance between a peak of a reception level obtained in advance at a deviation portion of the shield member and a trough of a reception level appearing before or after a predetermined number of the peaks. An apparatus for detecting an abnormality of a shield member, characterized by being provided.

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