JP2015121525A - Electroscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroscope configured to reliably detect breaking of a grounding wire.SOLUTION: An electroscope 1 includes: a first detection line 17 having one end which is always electrically short-circuited to a grounding wire 15, regardless of whether a ground terminal body 13 is connected to an object to be grounded such as a rail L2; and a ground determination section 25 which determines whether the ground terminal body 13 has brought into contact with the object to be grounded such as the rail L2. Thus, it becomes possible to determine whether the grounding wire 15 breaks or not regardless of the ground terminal body 13 being in contact with the object to be grounded such as the rail L2, thereby reliably detecting the breaking of the grounding wire 15.

Description

  The present invention relates to a voltage detector that detects a potential difference between a voltage detection target and a grounding target.

  For example, the voltage detector described in Patent Document 1 has a function of detecting whether or not a ground wire electrically connected to the ground terminal body is disconnected. That is, the voltage detector has a detection line having one end electrically connected to the ground terminal body and the other end connected to the power supply side.

  Then, when the grounding terminal body is connected to a grounding object such as a rail for rails, the detection unit uses the fact that the grounding line and the detection line are short-circuited via the grounding object. It is detected whether it is doing.

Japanese Patent No. 4443793

  In the invention described in Patent Document 1, since it is detected whether or not the ground line is disconnected using the fact that the ground line and the detection line are short-circuited via the ground object, the ground object and the ground are detected. Even if a contact failure occurs with the terminal, it is erroneously determined that the ground wire is disconnected.

  That is, the invention described in Patent Document 1 is an invention that uses a circuit (closed loop) that is electrically closed via a grounding object when no disconnection occurs. For this reason, when a contact failure occurs between the object to be grounded and the grounding terminal, since the circuit is electrically open even when the ground wire is not broken, the detection unit If the ground wire is disconnected, it will be misjudged.

  An object of this invention is to provide the voltage detector which can detect the disconnection of a grounding wire reliably in view of the said point.

  In order to achieve the above object, the present invention provides a voltage detection device that detects a potential difference between a voltage detection target (L1) and a grounding target (L2), and that makes electrical contact with the voltage detection target (L1). A voltage detection unit (5) for detecting a potential difference electrically connected to the metal fitting (5), the ground terminal body (13) in electrical contact with the grounding object (L2), and the voltage detection metal fitting (5). 21), a ground wire (15) for electrically connecting the voltage detector (21) and the ground terminal body (13), and whether the ground terminal body (13) is connected to the ground target (L2). The detection line (17) whose one end is always electrically short-circuited with the ground line (15) and the other end of the detection line (17) are connected to the detection line (17) from the ground line (15). ) And the continuity detection unit (23) for detecting the continuity state of the circuit leading to the current value of the current flowing through the detection line (17). A ground determination unit (25) for determining whether the ground terminal body (13) is in contact with the ground target (L2) using the change, and the other end side of the detection line (17) and the voltage detection unit ( 21) is connected via a power source to form a closed circuit.

  The detection line (17) according to the present invention is always short-circuited at one end with the ground line (15) regardless of whether the ground terminal body (13) is connected to the ground object (L2) or not. ing. For this reason, in the present invention, it is possible to detect whether the ground wire (15) is disconnected regardless of whether the ground terminal body (13) is in contact with the ground object (L2). .

  That is, in the present invention, even if the ground terminal body (13) is not in contact with the ground object (L2), if the ground line (15) is not disconnected, the detection is made from the ground line (15). Since the circuit leading to the line (17) is closed, it is possible to detect that the ground line (15) is not broken.

  On the other hand, even when the ground terminal body (13) is in contact with the ground object (L2), if the ground wire (15) is disconnected, the ground wire (15) to the detection line (17) Since the circuit leading to is opened, it is possible to detect the disconnection of the ground line (15).

Therefore, in the present invention, it is possible to detect whether the ground wire (15) is disconnected regardless of whether the ground terminal body (13) is in contact with the ground object (L2).
By the way, since the voltage detector detects the potential difference between the voltage detection target (L1) and the ground target (L2), when the ground terminal body (13) is not in contact with the ground target (L2), The potential difference cannot be detected. Therefore, the present invention includes a ground determination unit (25) that can determine whether or not the ground terminal body (13) is in contact with the ground target (L2).

  Incidentally, the reference numerals in parentheses for each of the above means are examples showing the correspondence with the specific means described in the embodiments described later, and the present invention is indicated by the reference numerals in the parentheses of the above respective means. It is not limited to specific means.

It is an external view of the voltage detector 1 which concerns on embodiment of this application. It is an electric system block diagram of the voltage detector 1 which concerns on 1st Embodiment of this application. It is a front view of the operation box 9 of the voltage detector 1 according to the first embodiment of the present application. (A) is sectional drawing of the ground terminal body 13 which concerns on 1st Embodiment of this invention. FIG. 4B is a bottom view of FIG. (A) And (b) is explanatory drawing which shows the determination principle whether the ground terminal body 13 contacted the rail L2. (A) And (b) is a figure which shows the characteristic of the voltage detector 1 which concerns on embodiment of this invention. It is a figure which shows the characteristic of the ground terminal body 13 which concerns on embodiment of this invention. (A) And (b) is explanatory drawing which shows the determination principle whether the ground terminal body 13 contacted the rail L2. It is a figure which shows the characteristic of the ground terminal body 13 which concerns on 3rd Embodiment of this application. It is a figure which shows the characteristic of the ground terminal body 13 which concerns on 4th Embodiment of this application. It is a figure which shows the characteristic of the ground terminal body 13 which concerns on 4th Embodiment of this application. (A)-(d) is a figure which shows the modification of the ground terminal body 13 which concerns on 4th Embodiment of this application.

  The “embodiment of the invention” described below shows an example of the embodiment. In other words, the invention specific items described in the claims are not limited to the specific means and structures shown in the following embodiments.

  In this embodiment, the present invention is applied to a DC voltage detector that detects a potential difference between an overhead line that supplies electric power to a train and the ground side (ground side). The arrows and the like indicating the directions given to the drawings are described for easy understanding of the relationship between the drawings. The present invention is not limited to the directions given in the drawings.

  At least one member or part described with at least a reference numeral is provided, except where “plurality”, “two or more”, and the like are omitted. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
1. Overview of Voltage Detector The voltage detector 1 according to the present embodiment is configured in a bowl shape as shown in FIG. The expansion / contraction part 3 is a site | part comprised by the telescopic shape, Comprising: It can expand-contract in the longitudinal direction. A voltage detection fitting 5 is provided at the distal end of the extension / contraction part 3 in the extending direction.

  The voltage detection fitting 5 is a part that is in electrical contact with the overhead line L1 (see FIG. 2) that is the object of voltage detection. The voltage detection fitting 5 according to the present embodiment is a metal member formed in a hook shape. For this reason, the operator can be locked so that the voltage detection fitting 5 is hooked on the overhead wire L1.

  The main body collar portion 7 is a cylindrical member, and a plurality of cylindrical members constituting the expansion / contraction portion 3 are accommodated therein so as to be able to appear and retract. An operation box 9 is provided in the main body collar 7. As shown in FIG. 2, an electric board on which the voltage detection unit 21 and the like are mounted is accommodated in the operation box 9.

  The voltage detection unit 21 is electrically connected to the voltage detection fitting 5 and detects a potential difference between the overhead line L1 and the ground side (hereinafter referred to as an overhead line voltage). In the present embodiment, the overhead wire voltage is divided using the electrical resistance RH and the electrical resistance RS, the voltage drop at the electrical resistance RS is measured by the voltage detection unit 21, and the resistance ratio between the electrical resistance RH and the electrical resistance RS is measured. The overhead line voltage is indirectly measured by calculating using.

  A ground terminal body 13 is connected to one end side (the lower end side in FIG. 1) of the main body collar portion 7 via a cable 11. As shown in FIG. 2, the ground terminal body 13 is in electrical contact with a rail L2 for railway that is a ground target. The details of the ground terminal body 13 will be described later.

  The cable 11 has at least a ground line 15, a first detection line 17, and a second detection line 19. That is, the cable 11 is a cable in which the ground wire 15 and the like are covered with the covering tube 11A and bundled into one cable. The covered tube 11A is made of a material having excellent bending resistance and oil resistance, such as a heat-resistant vinyl mixture.

  The ground line 15 electrically connects the voltage detection unit 21 and the ground terminal body 13. Regardless of whether the ground terminal body 13 is connected to the rail L <b> 2 or not, one end side of the first detection line 17 is always electrically short-circuited to the ground line 15.

  The other end side of the first detection line 17 is connected to the conduction detection unit 23. The continuity detection unit 23 detects the continuity state of a circuit (hereinafter referred to as a disconnection detection circuit) from the ground line 15 to the first detection line 17. That is, the continuity detection unit 23 supplies a current (hereinafter referred to as a disconnection detection signal) to the disconnection detection circuit.

  Then, when the disconnection detection signal can be detected, the continuity detection unit 23 determines that the disconnection has not occurred in the ground wire 15. The continuity detection unit 23 determines that a disconnection has occurred in the ground line 15 when the disconnection detection signal cannot be detected.

  The operation control unit 26 controls the operation state of any of the notification units 9 </ b> A to 9 </ b> D (see FIG. 3) provided in the operation box 9 based on a signal output from the continuity detection unit 23 and the like. In addition, alerting | reporting part 9A-9D which concerns on this embodiment is comprised by light-emitting bodies, such as LED.

  The notification unit 9 </ b> A is a light emitting unit that lights or blinks based on an output signal from the continuity detection unit 23. Specifically, the notification unit 9A is turned on when it is determined that the ground wire 15 is not broken, and is periodically blinked when it is determined that the ground wire 15 is broken. .

  One end side of the second detection line 19 is connected to the ground determination unit 25 as shown in FIG. The ground determination unit 25 determines whether the ground terminal body 13 has contacted the rail L <b> 2 based on a ground detection signal input via the second detection line 19.

  A signal indicating the determination result of the ground determination unit 25 is input to the operation control unit 26. When the signal indicating that the ground terminal body 13 is in contact with the rail L2 is input, the operation control unit 26 turns on the notification unit 9B and inputs a signal indicating that the ground terminal body 13 is not in contact with the rail L2. When it is done, the notification unit 9B is blinked.

  The display unit 27 is an information display unit configured by an LCD or the like. The display drive unit 29 causes the display unit 27 to display the overhead line voltage detected by the voltage detection unit 21. When the detected overhead line voltage is equal to or higher than a predetermined voltage (for example, 150 V), the operation control unit 26 operates a voice notification unit (not shown) such as a buzzer to notify the operator of that fact. .

  The power supply circuit 31 supplies power to the voltage detection unit 21, the continuity detection unit 23, the ground determination unit 25, and the like using the battery 31A as a power source. A power switch 9E (see FIG. 3) is provided on the lower side surface of the operation box 9. The power supply circuit 31 supplies power to the voltage detection unit 21, the continuity detection unit 23, the ground determination unit 25, and the like when the power switch 9E is turned on.

  The test high voltage generator 33 generates a voltage (hereinafter referred to as a test voltage) for confirming whether or not the voltage detector 21 or the like operates normally. The test cable 33 </ b> A is a cable for applying a test voltage to the voltage detection fitting 5.

  Note that the notification unit 9C illustrated in FIG. 3 is lit when the output voltage of the battery 31A is equal to or higher than a predetermined voltage. The notification unit 9D is lit when the output voltage of the battery 31A is less than the predetermined voltage. The predetermined voltage is a predetermined voltage and is a minimum voltage necessary for normal operation of the voltage detector 21 and the like.

2. 2. Ground Terminal Body 2.1 Structure of Ground Terminal Body As shown in FIG. 4A, the ground terminal body 13 has a terminal metal fitting 13A, a magnet portion 13B, a cover 13C covering these 13A and 12B, and the like. . The magnet part 13B generates an attractive force between the terminal fitting 13A and the grounded object such as the rail L2. Note that the magnet portion 13B according to the present embodiment has a columnar shape or a cylindrical shape.

  The terminal fitting 13A has a cylindrical portion 13D that covers the outer peripheral surface of the magnet portion 13B, and a disc portion 13E that covers one end in the axial direction (on the cable 11 side), and is formed in a cup shape. In other words, portions of the magnet portion 13B other than the portion facing the rail L2 are covered with the terminal fitting 13A.

  The ground line 15 and the first detection line 17 are electrically connected to the terminal fitting 13A. That is, the first detection line 17 is always electrically short-circuited with the ground line 15 via the metal terminal fitting 13A. In the present embodiment, the ground line 15 and the first detection line 17 are connected to the disk portion 13E of the terminal fitting 13A.

  The magnetic sensor 25A detects a change in the magnetic field induced by the magnet unit 13B. The magnetic sensor 25A is composed of a Hall IC. An output signal from the magnetic sensor 25 </ b> A is input to the ground determination unit 25 via the second detection line 19.

  In the present embodiment, a plurality of magnetic sensors 25A are provided. And as shown in FIG.4 (b), these several magnetic sensors 25A are arrange | positioned at equal intervals around the magnet part 13B. Specifically, three magnetic sensors 25A mounted on the annular substrate 25B are arranged at intervals of 120 degrees on the outer peripheral side of the terminal fitting 13A.

  4A is a power supply line that supplies power to the magnetic sensor 25A. The wiring 19B is a ground line for connecting the ground side of the magnetic sensor 25A. The wiring 19 </ b> A is inserted into the covered tube 11 </ b> A together with the ground wire 15, the first detection wire 17 and the second detection wire 19.

  The end 11B on the ground terminal body 13 side of the covered tube 11A reaches the inside of the cover 13C. The end portion 11B is provided with a locking portion 11C that is hooked and locked to the inner wall of the cover 13C.

  For this reason, even if the tension indicated by the arrow in FIG. 4A acts on the cable 11, the tension can be received by the locking portion 11C. Therefore, it can suppress that the said tension acts on the grounding wire 15 grade | etc., Directly. In addition, 11 C of latching parts which concern on this embodiment are comprised with fasteners, such as a tie wrap.

  The cover 13C is made of an electrically insulating material such as resin, and is molded (insert molded) in a state where the terminal fitting 13A and the substrate 25B are arranged. For this reason, the terminal fitting 13A and the substrate 25B are held by the cover 13C. The cover 13C according to the present embodiment is ABS resin or delrin.

2.2 Grounding determination of the ground terminal body The ground determination unit 25 determines whether or not the ground terminal body 13 is in contact with a metal grounding object such as the rail L2 using a change in the magnetic field detected by the magnetic sensor 25A. To do.

  That is, as shown in FIG. 5A, in a state where the ground terminal body 13 is not in contact with a metal grounding object such as the rail L2, the magnetic flux density at the portion where the magnetic sensor 25A is disposed is small. A metal grounding object such as the rail L2 is generally a ferromagnetic material. For this reason, when the ground terminal body 13 comes into contact with the rail L2, as shown in FIG. 5B, the rail L2 is magnetized and the magnetic flux density at the portion where the magnetic sensor 25A is disposed increases.

  As described above, the ground determination unit 25 according to the present embodiment determines whether or not the ground terminal body 13 is in contact with a metal ground target such as the rail L2 using the change in the magnetic field detected by the magnetic sensor 25A. To do.

3. Characteristics of the Voltage Detector According to the Present Embodiment The first detection line 17 according to the present embodiment is always connected to the ground wire 15 at one end regardless of whether the ground terminal body 13 is connected to the ground object such as the rail L2. Is short-circuited. For this reason, in this embodiment, it is possible to detect whether or not the ground wire 15 is disconnected regardless of whether or not the ground terminal body 13 is in contact with the ground object such as the rail L2.

  That is, in the present embodiment, even when the ground terminal body 13 is not in contact with the rail L2, if the ground wire 15 is not disconnected, the disconnection detection circuit is closed, so the ground wire 15 It is possible to detect that is not disconnected.

  On the other hand, even when the ground terminal body 13 is in contact with the rail L2, if the ground wire 15 is disconnected, the disconnection detection circuit is opened, so that the disconnection of the ground wire 15 is detected. It becomes possible.

Therefore, in the present embodiment, it is possible to detect whether or not the ground wire 15 is disconnected regardless of whether or not the ground terminal body 13 is in contact with the ground object such as the rail L2.
By the way, since the voltage detector 1 detects a potential difference between a voltage detection target such as the overhead line L1 and a grounding target such as the rail L2, when the ground terminal body 13 is not in contact with the rail L2, the above potential difference is detected. (Overhead voltage) cannot be detected.

  Therefore, in the present embodiment, a ground determination unit 25 that can determine whether or not the ground terminal body 13 is in contact with a ground target such as the rail L2 is provided. Thereby, in this embodiment, the voltage detector 1 which can detect the disconnection of the grounding wire 15 reliably can be obtained.

  In the present embodiment, the first detection line 17 is always electrically short-circuited to the ground line 15 via the terminal fitting 13A of the ground terminal body 13. As a result, it is possible to detect a connection failure between the ground wire 15 and the ground terminal body 13.

  That is, if the ground wire 15 and the first detection line 17 are directly connected, even if a connection failure occurs at the connection portion between the ground wire 15 and the ground terminal body 13. Since the ground line 15 and the first detection line 17 are short-circuited, the connection failure cannot be detected.

  On the other hand, in the present embodiment, the first detection line 17 is always electrically short-circuited with the ground line 15 via the ground terminal body 13 (terminal fitting 13A). It is possible to detect a connection failure with 13 as a disconnection of the ground wire 15.

In the present embodiment, a plurality of magnetic sensors 25A are provided, and the plurality of magnetic sensors 25A are arranged around the magnet portion 13B at equal intervals.
Thereby, in this embodiment, as shown in FIG. 6A and FIG. 6B, even when the ground terminal body 13 is in contact with a position shifted from the center of the ground target such as the rail L2, Since any one of the magnetic sensors 25A can detect a change in the magnetic field, it can be detected that the ground terminal body 13 is in contact with the grounding object such as the rail L2.

(Second Embodiment)
The ground determination unit 25 according to the present embodiment determines whether or not the ground terminal body 13 has contacted the ground target L2 by using a change in the current value of the current flowing through the first detection line 17 (disconnection detection signal). .

1. Configuration of Ground Terminal Body That is, as shown in FIG. 7, a detection terminal 17B made of a conductor such as metal is provided at a position separated from the terminal fitting 13A via an electrical insulating portion. The detection terminal 17B is electrically connected to the first detection line 17 via the third detection line 17C. In FIG. 7, the cover 13C is omitted.

  An electrical resistance R1 is provided on the terminal fitting 13A side from the connection portion P1 between the third detection line 17C and the first detection line 17 in the first detection line 17. In the third detection line 17C, an electrical resistance R2 is provided on the detection terminal 17B side from the connection portion P1. In the present embodiment, the resistance value of the electrical resistance R1 is set to a resistance value larger than the resistance value of the electrical resistance R2.

2. Determination of whether or not the ground terminal body is in contact with the rail When the ground terminal body 13 is not in contact with a metal grounding object such as the rail L2, as shown in FIG. The disconnection detection signal flows only in the circuit reaching the first detection line 17, that is, the disconnection detection circuit, and the disconnection detection signal does not flow in the third detection line 17C.

  When the ground terminal body 13 is in contact with a metal ground object such as the rail L2, as shown in FIG. 8B, the terminal fitting 13A and the detection terminal 17B are made of metal ground such as the rail L2. It becomes a state in which conduction is possible through the object.

  That is, when the ground terminal body 13 is in contact with the rail L2, the circuit (disconnection detection circuit) from the ground line 15 to the first detection line 17 and the terminal fitting 13A to the detection terminal 17B via the rail L2. To the circuit (hereinafter referred to as a ground detection circuit) is a parallel circuit.

  Therefore, since a disconnection detection signal flows in the ground detection circuit in addition to the disconnection detection circuit, a disconnection detection signal having a current value different from the current value of the disconnection detection signal that flows when the ground terminal body 13 is not in contact with the rail L2. Flowing.

  In this embodiment, it is determined whether or not the ground terminal body 13 is in contact with the rail L2 by using a change in the current value of the disconnection detection signal. Specifically, since the voltage drop at the electric resistance R3 changes in conjunction with the change in the current value of the disconnection detection signal, the ground determination unit 25 detects the change in the voltage drop, thereby detecting the ground terminal body 13. It is determined whether or not is in contact with the rail L2.

  Since the detection terminal 17B according to the present embodiment is formed in a cylindrical shape so as to surround the periphery of the terminal fitting 13A, even when the ground terminal body 13 is in contact with a position shifted from the center of the rail L2, It can be detected that the ground terminal body 13 is in contact with a ground object such as the rail L2.

  In the present embodiment, when the ground terminal body 13 is held on the rail L2 via an electrical insulator such as a plastic bag, the ground detection circuit is opened, so the current value of the disconnection detection signal does not change. . For this reason, in this embodiment, when the ground terminal body 13 is held on the rail L2 in the above-described state, it is determined that the ground terminal body 13 is not in contact with the rail L2.

  In the present embodiment, as shown in FIG. 7, the third detection line 17 </ b> C is connected in the middle of the first detection line 17, but the present embodiment is not limited to this, and the circuit is always closed. It is sufficient that the disconnection detection circuit to be connected and the ground detection circuit to be a closed circuit when in contact with the ground target are arranged in parallel.

Although the electrical resistance R2 is provided in this embodiment, the present embodiment can be implemented even if the electrical resistance R2 is eliminated.
(Third embodiment)
In the present embodiment, as shown in FIG. 9, a grip 13 </ b> F is provided on the cover 13 </ b> C of the ground terminal body 13. Thereby, when the operator removes the ground terminal body 13 from the rail L2 or the like, the ground terminal body 13 can be detached from the rail L2 or the like by gripping the grip portion 13F without pulling the cable 11.

(Fourth embodiment)
In the ground terminal body 13 according to the above-described embodiment, the contact surface that is in contact with the rail L2 constituted by the terminal fitting 13A and the magnet portion 13B has a flat shape as shown in FIG. 5B. . However, in the present embodiment, as shown in FIG. 10, when the ground terminal body 13 contacts the rail L <b> 2, a gap 40 is generated between the rail L <b> 2 and the outer periphery of the ground terminal body 13. . Specifically, it is as follows.

  The magnet part 13B includes a permanent magnet 13G, a magnetic pole part 13H, and a spacer 13J. The permanent magnet 13G is a permanent magnet such as an alnico magnet. The magnetic pole is made of a ferromagnetic metal such as SS400. The spacer 13J is a non-magnetic metal member such as C2700, and is disposed between the cylindrical portion 13D of the terminal fitting 13A, the permanent magnet 13G, and the magnetic pole portion 13H.

  For this reason, the magnetic field induced by the permanent magnet 13G is in a state of being confined in the spacer 13J. That is, all the magnetic field lines draw a closed curve, and all the magnetic field lines pass through the spacer 13J.

  In a state where the ground terminal body 13 is not in contact with the rail L2 (hereinafter referred to as a non-grounded state), as shown in FIG. 5A, the magnetic field lines coming out of the spacer 13J have a large curvature radius. A curved curve is drawn and returned to the spacer 13J again.

  For this reason, the magnetic flux density induced on the outer peripheral surface side of the spacer 13J is extremely smaller than the magnetic flux density induced in the spacer 13J. Therefore, in the non-grounded state, the magnetic sensor 25A cannot detect a magnetic field.

  By the way, the magnetic flux density induced outside the spacer 13J increases as the magnetic permeability increases. That is, the magnetic lines of force that have come out of the spacer 13J pass so as to concentrate on the portion where the magnetic resistance is small.

  For this reason, when the rail L2, which is a ferromagnetic material, is in contact with the ground terminal body 13 (hereinafter referred to as a grounded state), the magnetic flux density induced in the rail L2 increases, and therefore the magnetic sensor 25A is disposed. There is a possibility that the magnetic flux density induced in the part (hereinafter referred to as the sensor part) is smaller than that in the non-grounded state.

  That is, the total number of lines of magnetic force is the same regardless of the grounded state or the non-grounded state. For this reason, when the magnetic flux density induced in the rail L2 increases due to the grounding state, the number of magnetic lines of force passing through the sensor part is inevitably reduced and the magnetic flux density induced in the sensor part becomes small. Therefore, there is a possibility that the magnetic sensor 25A cannot detect the magnetic field even when the grounding state is established.

  On the other hand, in the present embodiment, as shown in FIG. 10, a gap 40 is generated between the rail L2 and the outer periphery of the ground terminal body 13 in the grounded state. Leakage magnetic flux to the magnetic sensor 25A side can be generated. Accordingly, the magnetic field can be reliably detected by the magnetic sensor 25A in the grounded state.

  The present embodiment is characterized in that a leakage magnetic flux toward the magnetic sensor 25A is generated by generating a gap 40 between the rail L2 and the outer periphery of the ground terminal body 13 in the grounded state. Is. Therefore, the specific configuration for forming the gap 40 is not questioned.

  That is, a portion of the outer peripheral end P2 of the ground terminal body 13 that contacts the rail L2 to be grounded on the virtual plane L3 parallel to the axial direction of the magnet section 13B (in this embodiment, the magnetic pole section 13H). If the projected outer peripheral edge P2 is closer to the projected magnetic sensor 25A than the projected contact surface of the magnetic pole portion 13H when the magnetic sensor 25A is projected. Can be configured.

  In the present embodiment, the gap 40 is configured by providing the inclined surface 13K inclined with respect to the contact surface of the magnetic pole portion 13H at the outer peripheral end P2 of the cylindrical portion 13D. However, since the present embodiment is characterized by generating a leakage magnetic flux from the gap 40 toward the magnetic sensor 25A, it may be configured as follows.

  That is, in the present embodiment, the inclined surface 13K is provided on the entire circumference of the outer peripheral end P2, but the inclined surface 13K may be provided discretely as shown in FIG. At this time, the inclined surface 13K may be provided at a position corresponding to the position of the magnetic sensor 25A.

  In the present embodiment, the gap 40 is formed by providing the inclined surface 13K. However, as shown in FIG. 12B, the gap 40 may be formed by setting the outer peripheral end P2 of the cylindrical portion 13D to a stepped shape. .

  In the present embodiment, the gap 40 is provided in the cylindrical portion 13D. However, the present invention is not limited to this, and reaches the magnetic pole portion 13H as shown in FIGS. 12 (c) and 12 (d). The gap 40 may be used. In addition, you may provide the clearance gap 40 shown in FIG.12 (b)-FIG.12 (d) discretely, as shown to Fig.12 (a).

  The dimension of the gap 40, that is, the contact surface of the magnetic pole portion 13H and the outer peripheral end P2, the dimensional difference H or the inclination angle θ is a value determined experimentally or by trial and error by FEM analysis using a computer or the like. . That is, the value varies depending on the position and sensitivity of the magnetic sensor 25A, the strength of the magnetic field induced by the magnet unit 13B, and the like.

(Fifth embodiment)
Although the wiring 19B according to the above-described embodiment, that is, the ground line for connecting the ground side of the magnetic sensor 25A is connected to the ground side via the ground line 15, the wiring 19B according to the present embodiment is connected to the ground side. It is independently connected to the ground side without going through the line 15.

Specifically, the wiring 19B is covered with the covering tube 11A and extends to the operation box 9 together with the grounding wire 15 and the like, and is connected to the negative electrode side of the battery 31A.
Thereby, even if it is a case where disconnection generate | occur | produces in the ground wire 15, magnetic sensor 25A can be operated. That is, it is possible to determine whether or not the ground terminal body 13 is in contact with a metal grounding object such as the rail L2 regardless of whether or not the ground wire 15 is disconnected.

(Other embodiments)
In the above-described embodiment, it is possible to determine whether the ground terminal body 13 is in contact with the grounding object such as the rail L2 using the change in the magnetic field or the change in the current value. However, the present invention is limited to this. is not.

  That is, for example, (a) a technique that makes it possible to determine whether or not the ground terminal body 13 has contacted the grounding object using a reflective optical sensor having a light emitting element and a light receiving element, and (b) detection provided on the ground terminal body 13 A method of generating an AC magnetic field by supplying an AC current to the coil, and detecting a magnetic loss due to an eddy current generated in the grounding object as a change in impedance of the detection coil when the ground terminal body 13 contacts the grounding object (c) There is a technique for detecting a change in capacitance generated in a gap between a metal plate disposed in a portion of the ground terminal body 13 parallel to the head of the rail L2 and the head of the rail L2.

  Further, the present invention is not limited to the above-described embodiment as long as it matches the gist of the invention described in the claims. Therefore, the electrical control units such as the continuity detection unit 23, the ground determination unit 25, and the operation control unit 26 may be configured by any of an analog circuit, a digital circuit, and a microcomputer control circuit using a microcomputer.

DESCRIPTION OF SYMBOLS 1 ... Voltage detector 3 ... Expansion / contraction part 5 ... Electric detection metal fitting 7 ... Main body collar part 9 ... Operation box 11 ... Cable 13 ... Grounding terminal body 13A ... Terminal metal fitting 13B ... Magnet part 13C ... Cover 13D ... Cylindrical part 13E ... Disk part 13F ... Grasping part 15 ... Ground line 17 ... First detection line 17B ... Detection terminal 17C ... Third detection line 19 ... Second detection line 19A ... Wiring 19B ... Wiring 21 ... Voltage detection part 23 ... Continuity detection part 25 ... Grounding determination Unit 25A ... Magnetic sensor 25B ... Substrate 26 ... Operation control unit 27 ... Display unit 29 ... Display drive unit 31 ... Power supply circuit 31A ... Battery

Claims (3)

In the voltage detector that detects the potential difference between the voltage detection object and the grounding object,
A voltage detection fitting that is in electrical contact with the voltage detection target;
A grounding terminal body in electrical contact with the grounding object;
A voltage detection unit that is electrically connected to the voltage detection fitting and detects the potential difference;
A grounding wire for electrically connecting the voltage detection unit and the grounding terminal body;
Regardless of whether or not the ground terminal body is connected to the ground object, one end side is always short-circuited with the ground line, and a detection line,
A continuity detection unit that is connected to the other end side of the detection line and detects a continuity state of a circuit from the ground line to the detection line;
A ground determination unit that determines whether or not the ground terminal body is in contact with the grounding object using a change in the current value of the current flowing through the detection line;
The voltage detector, wherein the other end side of the detection line and the voltage detection unit are connected via a power source to form a closed circuit. The ground terminal body is:
A metal terminal fitting to which the grounding wire and the detection line are electrically connected, and a detection terminal made of a conductor provided at a position separated from the terminal fitting via an electrical insulating portion; A detection terminal electrically connected to the detection line;
When the ground terminal body is in contact with the grounding object, a circuit extending from the grounding line to the detection line and a circuit extending from the terminal fitting to the detection terminal via the grounding object are parallel circuits. The voltage detector according to claim 1, wherein   The said detection terminal is formed in the cylindrical shape so that the circumference | surroundings of the said terminal metal fitting may be enclosed, The voltage detector of Claim 2 characterized by the above-mentioned.

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