JP6498543B2 - Clamp sensor and measuring device - Google Patents

Description

  The present invention relates to a clamp sensor including a pair of clamp portions and a measuring apparatus including the clamp sensor.

  As a clamp sensor of this type, a clamp sensor disclosed by the applicant in Patent Document 1 below is known. The clamp sensor includes a pair of sensor units that can be opened and closed. In this case, a contact portion is provided at each butt end portion of each sensor portion. In addition, the contact portion of one sensor portion is formed in a concave shape by contact surfaces having slope portions on both sides, and the contact portion of the local sensor portion is convex by contact surfaces having slope portions on both sides. It is formed in a shape. In this clamp sensor, when the clamp sensor is closed and the contact portions of the sensor portions are brought into contact with each other, the contact surface constituting the contact portion of one sensor portion formed in a concave shape and a convex shape are formed. Thus, the contact surface constituting the contact portion of the local sensor unit is in close contact with each other, thereby making it possible to improve measurement accuracy.

JP 2000-180475 A (page 2-3, FIG. 2)

  However, the conventional clamp sensor described above has the following problems to be improved. That is, in this clamp sensor, when the clamp sensor is closed, the contact surfaces formed at the contact portions of the sensor portions are in close contact with each other. On the other hand, for example, when the current flowing through the electric wire is detected by clamping the electric wire, the electric wire and the sensor unit come into contact with each other, and a straight line connecting the top and the bottom of the annular body constituted by each sensor unit is used as an axis. An external force in the rotational direction may act on each sensor unit. As described above, in the conventional clamp sensor, the contact surfaces are in close contact with each other. Therefore, when an external force in the rotational direction acts on each sensor unit, as shown in FIG. The abutment surface is such that one end in the thickness direction of the sensor portion on the abutment surface (the vertical direction in the figure) (the lower end in the example in the figure) serves as a fulcrum and the other end is separated from each other. Rotates (turns), thereby changing the distance between the contact surfaces. In this case, when the distance between the contact surfaces changes, the detection characteristics of the clamp sensor may change. Therefore, in the conventional clamp sensor, when such an external force in the rotation direction acts on each sensor unit, the detection characteristics of the clamp sensor may change and the detection accuracy may be lowered. It is rare.

  The present invention has been made in view of such a problem to be improved, and a main object of the present invention is to provide a clamp sensor and a measurement apparatus that can suppress a decrease in detection accuracy.

  In order to achieve the above object, the clamp sensor according to claim 1 is formed in an arc shape in plan view, and at least one of the clamp sensors is configured to be rotatable around the base end side, and each distal end side is closed. A clamp sensor comprising a pair of clamp parts constituting an annular body surrounding the clamp object, wherein each clamp part is formed with opposing surfaces facing each other in the closed state, respectively, at each tip part, Protruding from the opposing surfaces and engaging with each other in the closed state to restrict movement of the tip portions in the thickness direction of the clamp portions and to separate the opposing surfaces from each other Each of the opposing surfaces has a straight line along a direction connecting the distal end portion and the proximal end portion of the clamp portion of the annular body as an axis. The external force in the rotational direction is formed so as to be parallel to each other when not acting on each clamp portion in the closed state, and the engagement portion is a position excluding both end portions in the thickness direction on the opposing surfaces. And a fulcrum when each of the opposing surfaces is rotated by the external force in the rotation direction acting on the clamp portions in the closed state.

  The clamp sensor according to claim 2 is the clamp sensor according to claim 1, wherein the engaging portions are a plurality of first protrusions disposed on any one of the opposing surfaces so as to be spaced apart from each other. And a second protrusion disposed on the other facing surface and positioned between the first protrusions in the closed state.

  The clamp sensor according to claim 3 is the clamp sensor according to claim 2, wherein each of the first protrusions is disposed at a position excluding a central portion in the thickness direction on the one of the opposing surfaces. The second projecting portion is disposed at a position excluding the central portion in the thickness direction on the other facing surface.

  Further, the clamp sensor according to claim 4 is the clamp sensor according to claim 2, wherein each of the first protrusions is disposed at a position excluding a central portion in the thickness direction on the one of the opposing surfaces. The second protrusion is disposed at a central portion in the thickness direction on the other facing surface.

  According to a fifth aspect of the present invention, in the clamp sensor according to the fourth aspect, the second projecting portion is configured such that the tip portion is separated from one of the opposing surfaces in the closed state. .

  According to a sixth aspect of the present invention, there is provided a measuring apparatus that measures a measured amount of the clamp target based on the clamp sensor according to any of the first to fifth aspects and a detected amount detected by the clamp sensor. And a measurement unit.

  According to the clamp sensor according to claim 1 and the measuring device according to claim 6, the engaging portion that constitutes a fulcrum when the external force in the rotating direction acts on each clamp portion and each opposing surface rotates. The distance from the fulcrum when each facing surface rotates to the position where each facing surface is the most separated by disposing at the positions excluding both end portions in the thickness direction of each facing surface. It can be made shorter than the conventional structure which mutually contacts. For this reason, according to the clamp sensor and the current measuring device, the maximum amount of change in the separation distance between the opposing surfaces before and after the rotation can be reduced. Therefore, according to the clamp sensor and the current measuring device, it is possible to suppress a change in detection characteristics due to a variation in the separation distance between the facing surfaces when an external force is applied to each clamp portion in the rotation direction. A decrease in the detection accuracy of the detection amount and the measurement accuracy of the measurement amount based on the detection amount can be reliably suppressed.

  According to the clamp sensor according to claim 2 and the measuring device according to claim 6, the plurality of first protrusions disposed on one of the opposing surfaces so as to be spaced apart from each other, and the other A clamp portion in the thickness direction is provided with a simple configuration and a second projecting portion disposed between the first projecting portions in the closed state. The function of regulating the mutual movement of the tip parts, the function of separating the opposing surfaces from each other, and the function as a fulcrum when the opposing surfaces rotate can be surely exhibited by the engaging portion. For this reason, it is possible to reduce malfunctions caused by the complicated configuration of the engaging portion, and to sufficiently reduce the manufacturing cost of the clamp sensor and the current measuring device by the simple configuration of the engaging portion. Can do.

  According to the clamp sensor according to claim 3 and the measuring apparatus according to claim 6, the first protrusion is disposed at a position excluding the central portion in the thickness direction on any one of the opposing surfaces, and the other opposing surface. By disposing the second protrusion at a position excluding the central portion in the thickness direction on the surface, for example, even if a portion raised by welding exists at the central portion of one of the opposing surfaces, the second protrusion is present at that portion. It can avoid that the front-end | tip part of a projection part contact | abuts. For this reason, according to the clamp sensor and the current measuring device, it is possible to reliably prevent a change in the separation distance between the facing surfaces caused by a portion that has been raised by welding being crushed by contact with the second protrusion. it can.

  Moreover, according to the clamp sensor of Claim 4, and the measuring apparatus of Claim 6, each 1st projection part is arrange | positioned in the position except the center part of the thickness direction in any one opposing surface, and the other Compared to the configuration in which the second protrusion is disposed at a position other than the center in the thickness direction on the other facing surface by disposing the second protrusion at the center in the thickness direction on the facing surface, As a result of being able to bring the disposition position of the second protrusion serving as a fulcrum when each opposing surface rotates to the center in the thickness direction of either one of the opposing surfaces, the fulcrum (the tip of the second protrusion) The length from each of the opposing surfaces to the position where the opposing surfaces are most separated can be further shortened.

  According to the clamp sensor according to claim 5 and the measuring device according to claim 6, by configuring the second protrusion so that the tip portion is separated from one of the opposing surfaces in the closed state, for example, Even if there is a raised portion due to welding in the central portion of one of the opposing surfaces, it is possible to avoid the tip portion of the second protrusion from coming into contact with that portion, so that the raised portion is It is possible to reliably prevent a change in the separation distance between the facing surfaces caused by being crushed by contact with the second protrusion.

1 is a configuration diagram showing a configuration of a current measuring device 1. FIG. 3 is a front view of the clamp sensor 3. FIG. 3 is a perspective view of a clamp sensor 3. FIG. It is a front view of clamp sensor 3 in the state where clamp parts 22 and 52 were opened. It is a front view of clamp sensor 3 in the state where a part of body part 10 was removed. 3 is a perspective view of a fixed arm 20. FIG. 2 is an exploded perspective view of a fixed arm 20. FIG. 3 is a perspective view of a movable arm 50. FIG. 3 is an exploded perspective view of a movable arm 50. FIG. It is explanatory drawing explaining the engagement state of the engaging parts 32 and 62. FIG. It is explanatory drawing explaining the engagement state of the engaging parts 32 and 62 when the clamp parts 22 and 52 rotate. It is explanatory drawing explaining the state before and behind rotation of the conventional clamp sensor. It is explanatory drawing explaining the structure of the clamp sensor 103. FIG. It is explanatory drawing explaining the structure of the clamp sensor 203. FIG. It is explanatory drawing explaining operation | movement of the conventional clamp sensor.

  Hereinafter, embodiments of a clamp sensor and a measuring apparatus will be described with reference to the accompanying drawings.

  First, the configuration of a current measuring device 1 as an example of a measuring device will be described with reference to the drawings. The current measuring apparatus 1 shown in FIG. 1 is configured to be able to measure, for example, a current (an example of a measured amount) that flows in an electric wire 400 (an example of a clamp target: see FIG. 2). Specifically, as shown in FIG. 1, the current measuring device 1 includes a device main body 2 and a clamp sensor 3.

  As shown in FIG. 1, the apparatus main body 2 includes a measurement unit 2a, an operation unit 2b, a display unit 2c, and a control unit 2d.

  The measurement unit 2a performs measurement processing for measuring the current flowing through the electric wire 400 based on the magnetism (an example of the detected amount) detected by the clamp sensor 3 according to the control of the control unit 2d.

  The operation unit 2b includes various switches and outputs an operation signal when each switch is operated. The display unit 2c displays a measured current value and the like under the control of the control unit 2d. The control part 2d controls each part which comprises the apparatus main body 2 according to the operation signal output from the operation part 2b.

  The clamp sensor 3 is configured to be able to detect magnetism as an example of a detection amount in a state in which the electric wire 400 to be clamped is clamped (enclosed state: see FIG. 2). As shown in FIGS. 10, a fixed arm 20 and a movable arm 50 (hereinafter, the fixed arm 20 and the movable arm 50 are also collectively referred to as “arms 20 and 50”).

  2 and 3, the main body 10 includes a pair of cases 11 a and 11 b that can be fitted to each other, and as shown in FIG. 5, the base end 20 b side of the fixed arm 20 and the movable arm 50. The base end 50b side can be accommodated. As shown in FIGS. 2 and 3, the distal end portion 10 a of the main body portion 10 is formed with an opening 10 b that projects the distal end portion 20 a side of the fixed arm 20 and the distal end portion 50 a side of the movable arm 50. . Further, the side portion 10 c of the main body portion 10 is formed with an opening portion 10 d for projecting the lever 54 lever 54 provided at the base end portion 50 b of the movable arm 50.

  As shown in FIGS. 6 and 7, the fixed arm 20 includes a pair of covers 21 that can be fitted to each other, a core 41 (see FIG. 7), and a detection element 71 (for example, a Hall element: see the same figure). Has been. The fixed arm 20 includes a clamp part 22 and a support part 23 as shown in FIG. In this case, the front end 21 a side (see FIG. 7) of each cover 21 constitutes the clamp portion 22, and the base end portion 21 b side (see FIG. 7) of the cover 21 constitutes the support portion 23.

  As shown in FIG. 5, the clamp portion 22 is formed in a plan view arc shape. The clamp portion 22 is an annular shape that surrounds the electric wire 400 as a clamp target in a state where the distal end portion 22a and the distal end portion 52a of the clamp portion 52 described later in the movable arm 50 are closed (hereinafter also referred to as “closed state”). The body 300 is configured.

  Further, as shown in FIG. 6, a facing surface 31 is formed at the distal end portion 22 a of the clamp portion 22 (the distal end portion 21 a of each cover 21 constituting the clamp portion 22). In the closed state, the facing surface 31 faces a facing surface 61 (see FIG. 8), which will be described later, formed on the distal end portion 52a of the clamp portion 52 of the movable arm 50. Further, the facing surface 31 is a straight line (for example, the vertical direction in FIGS. 2 and 3) connecting the distal end portions 22a and 52a of the clamp portions 22 and 52 and the base end portions 22b and 52b in the annular body 300 (for example, When the external force in the rotation direction B (see FIG. 3) about the straight line 302) shown in FIG. 3 is not acting on the clamp portions 22 and 52 in the closed state, the parallel force is applied to the opposing surface 61 of the clamp portion 52. (See FIG. 10).

  Further, as shown in FIG. 6, an engaging portion 32 is disposed on the facing surface 31. The engaging portion 32 includes projecting portions 33a to 33d (corresponding to first projecting portions: hereinafter, also referred to as “projecting portions 33” when not distinguished) arranged so as to be spaced apart from each other. Yes. In this case, as shown in the figure, the protrusions 33a to 33d are formed on the opposing surface 31 at the end 31a in the thickness direction A of the clamp portion 22 parallel to the central axis 301 of the annular body 300 (see also FIG. 3). It is arrange | positioned in the position except.

  Specifically, in the clamp sensor 3, as shown in FIG. 6, the protrusions 33 a and 33 b are located closer to the clamp portion 22 than to the end portion 31 a at the outer peripheral side (upper side in the drawing) of the clamp portion 22. It is disposed on the central portion 31b (joint portion of the covers 21 and 21) side in the thickness direction A and at a position excluding the central portion 31b, more specifically, at two positions separated from the central portion 31b by the same distance. Yes. Further, the protrusions 33c and 33d are located at the central portion 31b side of the edge portion 31a at the inner peripheral side (lower side in the figure) of the clamp portion 22 and excluding the central portion 31b, more specifically, The central portion 31b is disposed at two positions separated by the same distance.

  In the closed state, the engaging portion 32 engages with an engaging portion 62 (described later) disposed on the opposing surface 61 of the clamp portion 52 in the movable arm 50 (see FIG. 10), and the clamp portions 22 and 52 are engaged. Of the clamp portions 22 and 52 in the thickness direction A (along the thickness direction A) is restricted, and the opposing surfaces 31 and 61 of the clamp portions 22 and 52 are separated from each other. Have. Further, the engaging portion 32 is attached to the clamp portions 22 and 52 in the closed state when the clamp portions 22 and 52 are rotated (twisted) by the external force in the rotation direction B (see FIG. 3). Accordingly, a fulcrum is formed when the opposing surfaces 31 and 61 rotate (turn) (function as a fulcrum: see FIG. 11).

  Further, as shown in FIG. 7, the core 41 and the detection element 71 are disposed in the clamp portion 22. In this case, the detection element 71 is disposed at the distal end portion 22a of the clamp portion 22 (between the distal end portion of the core 41 and the facing surface 31).

  The support part 23 is provided in the base end part 22b of the clamp part 22, as shown in FIG. Further, as shown in FIG. 5, the support portion 23 is attached to the main body portion 10 with screws 80, whereby the fixed arm 20 (the clamp portion 22 and the support portion 23) is fixed to the main body portion 10. .

  As shown in FIGS. 8 and 9, the movable arm 50 includes a pair of covers 51 and 51 and a core 42 (see FIG. 9) that can be fitted to each other. Further, as shown in FIG. 8, the movable arm 50 includes a clamp portion 52, a support portion 53, and a lever 54. In this case, the distal end portion 51 a side (see FIG. 9) of the cover 51 constitutes the clamp portion 52, and the proximal end portion 51 b side (see FIG. 9) of the cover 51 constitutes the lever 54. Further, the portion of the cover 51 between the component part of the clamp part 52 and the component part of the lever 54 constitutes the support part 53.

  As shown in FIG. 5, the clamp part 52 is formed in an arc shape in plan view. The clamp portion 52 is configured to be rotatable about a support shaft 53a disposed on a support portion 53 provided on the base end portion 52b side (that is, centering on the base end portion 52b side). Yes. Further, as shown in FIG. 9, the core 42 is disposed in the clamp portion 52.

  Further, as shown in FIG. 8, the front end portion 52 a of the clamp portion 52 (the front end portion 51 a of each cover 51 constituting the clamp portion 52) is opposed to the opposed surface 31 of the clamp portion 22 in the closed state. 61 is formed. Further, the facing surface 61 is parallel to the facing surface 31 of the clamp portion 22 when the external force in the rotation direction B (see FIG. 3) does not act on the clamp portions 22 and 52 in the closed state. It is formed (see FIG. 10).

  Further, as shown in FIG. 8, an engaging portion 62 is disposed on the facing surface 61. The engaging portion 62 includes projecting portions 63a to 63d (corresponding to second projecting portions: hereinafter referred to as “projecting portions 63” when not distinguished) arranged so as to be spaced apart from each other. Yes. In this case, the protrusions 63a to 63d are disposed at positions on the facing surface 61 excluding the end 61a in the thickness direction A of the clamp portion 52 parallel to the central axis 301 of the annular body 300, as shown in FIG. ing.

  Specifically, in the clamp sensor 3, as shown in FIG. 8, the protrusions 63 a and 63 b are arranged in the thickness direction A more than the end 61 a at the outer peripheral side (upper side in the figure) of the clamp 52. The central portion 61b (joint portion of the covers 51 and 51) side is disposed at a position excluding the central portion 61b, more specifically, at two positions separated from the central portion 61b by the same distance. Further, as shown in FIG. 10, the arrangement positions of the protrusions 63a and 63b are located in the gap 34a between the protrusions 33a and 33b in the clamp part 22 when the clamp parts 22 and 52 are closed (see FIG. 10). To be inserted).

  Further, the protrusions 63c and 63d are located at the central portion 61b side of the end portion 61a at the edge on the inner peripheral side (lower side in the figure) of the clamp portion 52, and more specifically at positions excluding the central portion 61b. The central portion 61b is disposed at two positions separated by the same distance. Further, as shown in FIG. 10, the arrangement positions of the protrusions 63c and 63d are located in the gap 34b between the protrusions 33c and 33d in the clamp part 22 when the clamp parts 22 and 52 are closed (see FIG. 10). To be inserted).

  In the closed state, the engaging portion 62 engages with the engaging portion 32 disposed on the opposing surface 31 of the clamp portion 22 (see FIG. 10), and the clamp portions 22 and 52 in the thickness direction A are engaged with each other. In addition to restricting the movement of the tip portions 22a and 52a, the opposed surfaces 31 and 61 of the clamp portions 22 and 52 are separated from each other. Further, the engaging portion 62 constitutes a fulcrum when the opposing surfaces 31 and 61 are rotated by the external force in the rotation direction B (see FIG. 3) acting on the clamp portions 22 and 52 in the closed state (as fulcrums). Works: see FIG. 11).

  The support part 53 is provided in the base end part 52b of the clamp part 52, as shown in FIG. The support portion 53 is pivotally supported on the main body portion 10 by a support shaft 53a (see FIGS. 5 and 9), whereby the movable arm 50 (the clamp portion 52, the support portion 53, and the lever 54) supports the support shaft 53a. It is pivotable as a center. Further, an urging member (for example, a torsion coil spring) (not shown) is disposed between the support portion 53 and the main body portion 10, and the tip portions 22 a and 52 a of the clamp portions 22 and 52 are arranged by this urging member. The movable arm 50 (clamp part 52) is urged in the direction in which is closed.

  As shown in FIG. 8, the lever 54 is provided at the end of the support portion 53. The lever 54 is used when the movable arm 50 is rotated to open and close the distal end portions 22a and 52a of the clamp portions 22 and 52. In this case, as shown in FIG. 4, when the lever 54 is pushed into the main body 10 side, the tip portions 22a and 52a of the clamp portions 22 and 52 are opened (hereinafter also referred to as "open state"). When the pushing of the lever 54 is released, the tip portions 22a and 52a are closed by the urging force of the urging member.

  Next, a method for using the current measuring device 1 will be described with reference to the drawings.

  In the clamp sensor 3 of the current measuring device 1, when not in use (initial state), the tip portions 22a and 52a of the clamp portions 22 and 52 are closed as shown in FIGS. In this closed state, as shown in FIG. 10, the opposing surfaces 31, 61 of the clamp portions 22, 52 of the arms 20, 50 face each other, and the engaging portions 32, 62 of the clamp portions 22, 52 engage with each other. ing. Specifically, the protrusions 63 a and 63 b that constitute the engagement part 62 are positioned in the gap 34 a between the protrusions 33 a and 33 b that constitute the engagement part 32, and the protrusions 33 c and 33 c that constitute the engagement part 32. Protrusions 63c and 63d constituting the engaging portion 62 are located in the gap 34b between 33d.

  Further, the engagement of the engaging portions 32 and 62 restricts the movement of the distal end portions 22a and 52a of the clamp portions 22 and 52 in the thickness direction A (see FIG. 10), and the clamp portions 22 and 52 face each other. The surfaces 31 and 61 are separated from each other. Further, when not in use, since the external force in the rotation direction B (see FIG. 3) does not act on the clamp parts 22 and 52 in the closed state, the opposing surfaces 31 and 61 are parallel to each other as shown in FIG. Maintained in a state. In this state, the tip portions of the protrusions 63 a to 63 d of the clamp portion 52 are in contact with the facing surface 31 of the clamp portion 22.

  For example, when measuring the current as the amount to be measured flowing in the electric wire 400 (see FIG. 2) as the clamp target, first, the electric wire 400 as the clamp target is clamped by the clamp portions 22 and 52 of the clamp sensor 3. . Specifically, as shown in FIG. 4, the lever 54 of the movable arm 50 is pushed into the main body 10 side. At this time, the clamp part 52 rotates about the base end part 52b side (support shaft 53a), the tip part 52a of the clamp part 52 is separated from the tip part 22a of the clamp part 22, and the tip parts 22a and 52a are separated. Opened open state.

  Next, the clamp portions 22 and 52 in the open state are brought close to the electric wire 400, and the electric wire 400 is passed through the gap between the tip portions 22a and 52a of the clamp portions 22 and 52, and as shown in FIG. The electric wire 400 is positioned in the sandwiched area.

  Subsequently, the pushing of the lever 54 is released. At this time, the urging force of the urging member rotates the clamp portion 52 in a direction in which the distal end portion 52a of the clamp portion 52 approaches the distal end portion 22a of the clamp portion 22, and the distal end portions 22a and 52a are closed. . As a result, as shown in FIG. 2, the electric wire 400 is clamped by the clamp portions 22 and 52, and the annular body 300 surrounding the electric wire 400 is configured by the clamp portions 22 and 52. Further, when the electric wire 400 is clamped by the clamp portions 22 and 52, the detection element 71 disposed in the clamp portion 22 detects magnetism generated by the current flowing through the electric wire 400 and outputs a detection signal.

  Here, for example, when the electric wire 400 is clamped, the electric wire 400 and the clamp portions 22 and 52 come into contact with each other, and as shown in FIG. When an external force is applied, the opposing surfaces 31 and 61 rotate (turn) in the rotation direction B as the clamp portions 22 and 52 rotate (twist). In the clamp sensor 3, the opposing surfaces 31 and 61 are separated from each other without abutting, and the engaging portion 32 and the protruding portion 63 are configured by a protruding portion 33 formed so as to protrude from the opposing surfaces 31 and 61. The engaging part 62 comprised by is engaged. For this reason, as shown in the figure, the opposed surfaces 31 and 61 rotate with the engaging portion (in this example, the tips of the protrusions 63a and 63c) as a fulcrum.

  On the other hand, as shown in FIG. 12, in the conventional configuration in which the opposing surfaces 31 and 61 are in contact with each other in the closed state (a state indicated by a solid line in the figure), the external force in the rotation direction B is closed. , 52, as shown by the broken line in the figure, one end of the opposed surfaces 31, 61 (the lower end in the example of the figure) is turned as a fulcrum, and the opposite surfaces 31, 61 At the other end (the upper end in the example in the figure), the facing surfaces 31 and 61 are farthest apart. In this case, assuming that the angle at which the opposing surfaces 31 and 61 rotate (the twist angle of the clamp portions 22 and 52) is θ and the length in the thickness direction A of the opposing surfaces 31 and 61 is T2, the opposing surfaces 31 and 61 are The separation distance L3 (see the figure) at the end portion that is the most separated is L3≈θ × T2. That is, in this configuration, the distance between the opposing surfaces 31 and 61 changes by a maximum of L3≈θ × T2 before and after the opposing surfaces 31 and 61 rotate.

  On the other hand, in the clamp sensor 3, the separation distance when the external force in the rotation direction B is not acting is L0 (see FIG. 10), and the separation distance when the external force is acting is L2 (see FIG. 11). Then, the maximum change amount L1 (L2−L0) of the separation distance between the opposing surfaces 31 and 61 before and after the rotation of the opposing surfaces 31 and 61 is θ, where the angle at which the opposing surfaces 31 and 61 rotate is θ. Assuming that the length from the position of the tip of the protrusions 63a, 63c to the end of the opposing surfaces 31, 61 (the upper end in FIG. 11) is T1, the distance changes by a maximum of L1≈θ × T1. In this case, in the clamp sensor 3, the protrusion 33 is disposed at a position excluding the end 31 a on the facing surface 31, that is, closer to the central portion 31 b in the thickness direction A than the end 31 a, and the protrusion 63 is opposed to The surface 61 is disposed at a position excluding the end portion 61a, that is, closer to the central portion 61b in the thickness direction A than the end portion 61a. For this reason, in this clamp sensor 3, the length (above-mentioned T1) from the position which becomes a fulcrum when the opposing surfaces 31 and 61 rotate to the end portion in the thickness direction A where the opposing surfaces 31 and 61 are most separated from each other. The opposing surfaces 31 and 61 are shorter than the length T2 in the thickness direction A. Therefore, in this clamp sensor 3, when the rotation angles of the opposing surfaces 31 and 61 are the same, that is, when the external force in the rotation direction B acting on the clamp portions 22 and 52 is the same, it is opposed to the conventional configuration. It is clear that the maximum amount of change in the separation distance between the opposing surfaces 31 and 61 before and after the rotation of the surfaces 31 and 61 can be suppressed.

  Further, in the clamp sensor 3, the protruding portion 33 is disposed at a position excluding the central portion 31 b in the thickness direction A on the opposing surface 31, and the protruding portion 63 is provided at a position excluding the central portion 61 b in the thickness direction A on the opposing surface 61. It is arranged. Here, in this clamp sensor 3, the clamp part 22 is comprised by joining the two covers 21, and the junction part of each cover 21 is located in the center part 31b of the opposing surface 31. FIG. Moreover, since each cover 21 is joined by welding, in general, the joining portion is raised (projects from other portions). For this reason, for example, in the configuration in which the protruding portion 63 is disposed at the central portion 61b of the facing surface 61, the tip end portion of the protruding portion 63 is in the central portion 31b of the facing surface 31, that is, the portion that is raised by welding in the closed state. It will abut.

  In this case, the raised portion due to the welding is gradually crushed by repeated contact with the tip of the protrusion 63. For this reason, in the configuration in which the protrusion 63 is disposed in the central portion 61b of the facing surface 61, the distance between the facing surfaces 31, 61 changes (closes) as the number of uses increases. In contrast, in the clamp sensor 3, as described above, since the protrusion 63 is disposed at a position excluding the central portion 61 b of the facing surface 61, the tip of the protruding portion 63 is located at the center of the facing surface 31. There is no contact with the portion 31b (the portion raised by welding). For this reason, in the clamp sensor 3, it is possible to reliably prevent a change in the separation distance between the facing surfaces 31 and 61 due to a portion that has been swelled by welding being crushed by contact with the protrusion 63. Yes.

  Next, the operation unit 2b of the apparatus main body 2 is operated to instruct the start of measurement. At this time, the control unit 2d of the apparatus body 2 controls the measurement unit 2a to execute measurement processing. In this measurement process, the measurement unit 2a uses the detection signal (magnetism as a detection amount detected by the clamp sensor 3) output from the detection element 71 of the clamp sensor 3 to cause a current flowing through the electric wire 400 (for the clamp target). Measured amount). Subsequently, the control unit 2d controls the display unit 2c to display the current value measured by the measurement unit 2a.

  In this case, in the clamp sensor 3, even if an external force in the rotation direction B acts on the clamp parts 22 and 52 in the closed state, as described above, the opposing surfaces 31 and 61 accompanying the rotation of the clamp parts 22 and 52. The maximum amount of change in the separation distance between them is kept small. For this reason, in the clamp sensor 3 and the current measuring device 1, it is possible to suppress a change in detection characteristics due to a change in the separation distance between the opposing surfaces 31, 61. As a result, the detection accuracy of the detection amount and the detection amount are increased. It is possible to reliably suppress a decrease in the measurement accuracy of the measurement amount based on the measurement target.

  Next, when the measurement is completed, the clamp portions 22 and 52 are opened by pushing the lever 54, and then the electric wire 400 is passed through the gap between the tip portions 22a and 52a of the clamp portions 22 and 52. Thus, the clamp sensor 3 is separated from the electric wire 400. Next, the pushing of the lever 54 is released, and the clamp portions 22 and 52 are closed. Then, when measuring the electric current which flows into the other electric wire 400, above-mentioned operation is performed.

  As described above, according to the clamp sensor 3 and the current measuring device 1, the external force in the rotation direction B acts on the clamp portions 22 and 52 to form a fulcrum when the opposing surfaces 31 and 61 rotate. By disposing the portions 32 and 62 at positions other than the end portions 31a and 61a in the thickness direction A of the opposing surfaces 31 and 61, the opposing surfaces 31 and 61 are the most from the fulcrum when the opposing surfaces 31 and 61 rotate. The length to the position where it leaves | separates can be shortened rather than the conventional structure which the opposing surfaces 31 and 61 contact | abut in a closed state. For this reason, according to the clamp sensor 3 and the current measuring device 1, the maximum amount of change in the separation distance between the opposing surfaces 31 and 61 before and after the rotation can be reduced. Therefore, according to the clamp sensor 3 and the current measuring device 1, a change in detection characteristics due to a variation in the separation distance between the opposing surfaces 31 and 61 when an external force acts on the clamp portions 22 and 52 in the rotation direction B is reduced. As a result of the suppression, it is possible to reliably suppress a decrease in the detection accuracy of the detection amount and the measurement accuracy of the measurement amount based on the detection amount.

  In addition, according to the clamp sensor 3 and the current measuring device 1, the plurality of protrusions 33 disposed on the facing surface 31 so as to be spaced apart from each other and the protrusions disposed on the facing surface 61 in the closed state. A function of regulating the mutual movement of the tip end portions 22a and 52a in the thickness direction A while having a simple configuration by providing the engaging portions 32 and 62 with the protruding portion 63 positioned between the portions 33. The engaging portions 32 and 62 can reliably exhibit the function of separating the opposing surfaces 31 and 61 from each other and the function as a fulcrum when the opposing surfaces 31 and 61 rotate. For this reason, while being able to reduce the malfunctioning resulting from the complicated structure of the engaging parts 32 and 62, the structure of the engaging parts 32 and 62 is simple, and the clamp sensor 3 and the current measuring device 1 can be reduced. Manufacturing cost can be reduced sufficiently.

  Further, according to the clamp sensor 3 and the current measuring device 1, the protrusion 33 is disposed at a position excluding the central portion 31 b in the thickness direction A on the opposing surface 31, and the central portion 61 b in the thickness direction A on the opposing surface 61 is provided. By disposing the protruding portion 63 at the excluded position, for example, even if there is a raised portion at the central portion 31b of the opposing surface 31, the tip end portion of the protruding portion 63 abuts on that portion. It can be avoided. For this reason, according to the clamp sensor 3 and the current measuring device 1, it is possible to reliably prevent a change in the separation distance between the facing surfaces 31 and 61 caused by a portion that is raised by welding being crushed by contact with the protrusion 63. can do.

  Next, a clamp sensor 103 shown in FIG. 13 as another example of the clamp sensor will be described. In addition, in the following description, the illustration about the same component as the above-mentioned clamp sensor 3 and the overlapping description are abbreviate | omitted. The clamp sensor 103 includes a fixed arm 120 and a movable arm 150 as shown in FIG. The fixed arm 120 includes a clamp part 122, and the movable arm 150 includes a clamp part 152. In addition, an opposing surface 131 is formed at the distal end portion 122 a of the clamp portion 122, and an opposing surface 161 is formed at the distal end portion 152 a of the clamp portion 152. The facing surfaces 131 and 161 face each other in the closed state, and are formed to be parallel to each other when the external force in the rotation direction B is not acting on the clamp portions 122 and 152 in the closed state.

  Further, as shown in FIG. 13, an engaging portion 132 is disposed on the facing surface 131. The engaging portion 132 includes projecting portions 133a to 133d (corresponding to the first projecting portion: hereinafter, also referred to as “projecting portion 133” when not distinguished) arranged so as to be spaced apart from each other. Yes. In this case, as shown in the figure, each protrusion 133 is disposed at a position excluding the end 131a in the thickness direction A on the facing surface 131.

  Specifically, the protrusions 133a and 133b are located on the side of the central portion 131b in the thickness direction A from the end portion 131a on the outer peripheral side (the front side in FIG. 13) of the clamp portion 122 and exclude the central portion 131b. The positions are arranged at two positions separated from each other by the same distance from the central portion 131b. Further, the protrusions 133c and 133d are more specifically positioned at the center 131b side than the end 131a at the edge on the inner peripheral side of the clamp portion 122 (the back side in the drawing), and excluding the center 131b. Are respectively disposed at two positions separated from the central portion 131b by the same distance. In addition, each protrusion 133 is configured such that the tip end abuts against the opposing surface 161 of the clamp portion 152 in the closed state.

  Further, as shown in FIG. 13, an engaging portion 162 is disposed on the facing surface 161. The engaging portion 162 includes projecting portions 163a and 163b (corresponding to the second projecting portion: hereinafter, also referred to as “projecting portion 163” when not distinguished). In this case, each protruding portion 163 is disposed at a position excluding the end portion 161 a in the thickness direction A on the facing surface 161. Specifically, the protruding portion 163a is an edge portion of the opposing surface 161 on the outer peripheral side of the clamp portion 122 (the front side in the drawing in the figure), and is disposed in the central portion 161b of the opposing surface 161 in the thickness direction A. In the closed state, it is positioned in the gap 134a between the protrusions 133a and 133b. Further, the protruding portion 163b is an edge of the opposing surface 161 on the inner peripheral side (the back side of the paper surface in the figure) of the clamp portion 122, and is disposed in the central portion 161b of the opposing surface 161 in the thickness direction A. In the closed state, it is located in the gap 134b between the protrusions 133c and 133d. In addition, each protrusion 163 is configured such that, in the closed state, the tip portion is separated from the facing surface 131 (in this example, the central portion 131b) of the clamp portion 122.

  In this clamp sensor 103, when the external force in the rotation direction B acts on the clamp portions 122 and 152, the opposing surfaces 131 and 161 rotate with the tip end portion (contact portion with the opposing surface 161) of the projection 133 as a fulcrum. To do.

  Also in the clamp sensor 103, since the engaging portions 132 and 162 are disposed at positions other than the end portions 131a and 161a in the thickness direction A on the opposing surfaces 131 and 161, the opposing surfaces 131 and 161 are rotated. The length from the fulcrum to the position where the opposed surfaces 131 and 161 are the most separated can be made shorter than the conventional configuration. Therefore, in this clamp sensor 103 as well, the maximum amount of change in the separation distance between the opposing surfaces 131 and 161 before and after the rotation can be suppressed, so that the detection characteristic due to the variation in the separation distance between the opposing surfaces 131 and 161 can be reduced. As a result of suppressing the change to be small, it is possible to reliably suppress a decrease in the detected amount.

  Further, in the clamp sensor 103, each protrusion 133 is disposed at a position excluding the central portion 131b in the thickness direction A on the facing surface 131, and the protrusion 163 is disposed at the central portion 161b in the thickness direction A on the facing surface 161. Has been. For this reason, according to the clamp sensor 103, each protrusion serving as a fulcrum when the opposing surfaces 131 and 161 rotate is compared with the configuration in which the protrusion 163 is disposed at a position excluding the central portion 161b. As a result of being able to bring the arrangement position of 133 close to the central portion 131b of the opposing surface 131, the length from the fulcrum (the tip portion of the projection 133) to the position where the opposing surfaces 131 and 161 are farthest away can be further shortened. it can.

  In addition, the clamp sensor 103 is configured such that, in the closed state, the distal end portion of each protrusion 163 is separated from the opposing surface 131 (in this example, the central portion 131b) of the clamp portion 122. For this reason, according to the clamp sensor 103, for example, even if a portion raised by welding exists in the central portion 131b of the facing surface 131, it is avoided that the tip portion of the protruding portion 163 contacts the portion. Therefore, it is possible to reliably prevent a change in the separation distance between the facing surfaces 131 and 161 due to the swelled portion being crushed by contact with the protrusion 163.

  Next, a clamp sensor 203 shown in FIG. 14 as another example of the clamp sensor will be described. In addition, in the following description, the illustration about the same component as the above-mentioned clamp sensor 3 and 103 and the overlapping description are abbreviate | omitted. The clamp sensor 203 includes a fixed arm 220 and a movable arm 250 as shown in FIG. The fixed arm 220 includes a clamp part 222, and the movable arm 250 includes a clamp part 252. In addition, an opposing surface 231 is formed at the distal end portion 222 a of the clamp portion 222, and an opposing surface 261 is formed at the distal end portion 252 a of the clamp portion 252. The facing surfaces 231 and 261 face each other in the closed state, and are formed to be parallel to each other when the external force in the rotation direction B is not acting on the clamp portions 222 and 252 in the closed state.

  Further, as shown in FIG. 14, an engaging portion 232 is disposed on the facing surface 231. The engaging portion 232 includes projecting portions 233a to 233d (corresponding to first projecting portions: hereinafter, also referred to as “projecting portions 233” when not distinguished) arranged so as to be spaced apart from each other. Yes. In this case, each protrusion 233 is disposed at a position excluding the end portion 231a in the thickness direction A on the facing surface 231 as shown in FIG.

  Specifically, the protrusions 233a and 233b are located on the central portion 231b side in the thickness direction A with respect to the edge portion 231a on the outer peripheral side (the front side in FIG. 14) of the clamp portion 222 and exclude the central portion 231b. The positions are arranged at two positions that are spaced apart from the central portion 231b by the same distance. Further, the protrusions 233c and 233d are more specifically positioned at the center portion 231b side than the end portion 231a and excluding the center portion 231b at the edge on the inner peripheral side (the back side in the drawing in the figure) of the clamp portion 222. Are respectively disposed at two positions separated from the central portion 231b by the same distance. In addition, each protrusion 233 is configured such that, in the closed state, the tip portion is separated from the facing surface 261 of the clamp portion 252.

  Further, as shown in FIG. 14, an engaging portion 262 is disposed on the facing surface 261. The engaging portion 262 includes projecting portions 263a and 263b (corresponding to the second projecting portion: hereinafter, also referred to as “projecting portion 263” when not distinguished). In this case, each protrusion 263 is disposed at a position excluding the end 261 a in the thickness direction A on the facing surface 261. Specifically, the protruding portion 263a is an edge of the opposing surface 261 on the outer peripheral side of the clamp portion 222 (the front side in the drawing in the figure) and is disposed in the central portion 261b of the opposing surface 261 in the thickness direction A. In the closed state, it is positioned in the gap 234a between the protrusions 233a and 233b. Further, the protruding portion 263b is an edge portion of the opposing surface 261 on the inner peripheral side (the back side of the paper surface in the figure) of the clamp portion 222, and is disposed in the central portion 261b of the opposing surface 261 in the thickness direction A. In the closed state, it is located in the gap 234b between the protrusions 233c and 233d. In addition, each projecting portion 263 is configured such that, in the closed state, the tip portion abuts against the opposing surface 231 (in this example, the central portion 231b) of the clamp portion 222.

  In this clamp sensor 203, when the external force in the rotation direction B acts on the clamp portions 222 and 252, the opposing surfaces 231 and 261 rotate with the tip portion (contact portion with the opposing surface 231) of the protrusion 263 as a fulcrum. To do.

  Also in this clamp sensor 203, since the engaging portions 232 and 262 are arranged at positions on the opposing surfaces 231 and 261 excluding the end portions 231a and 261a in the thickness direction A, when the opposing surfaces 231 and 261 rotate. The length from the fulcrum to the position where the opposing surfaces 231 and 261 are most separated can be made shorter than the conventional configuration. Therefore, in this clamp sensor 203 as well, since the maximum amount of change in the separation distance between the opposing surfaces 231 and 261 before and after rotation can be suppressed, the detection characteristic due to the variation in the separation distance between the opposing surfaces 231 and 261 can be reduced. As a result of suppressing the change to be small, it is possible to reliably suppress a decrease in detection accuracy of the detected amount.

  Further, in the clamp sensor 203, a protrusion 263 is disposed at the central portion 261b of the facing surface 261, and the tip of each protrusion 263 is configured to contact the facing surface 231 of the clamp portion 222 in the closed state. Yes. For this reason, according to this clamp sensor 203, the length from the fulcrum (tip portion of the projection 233) when the opposing surfaces 231 and 261 rotate to the position where the opposing surfaces 231 and 261 are most separated is further shortened. be able to.

  Note that the configurations of the clamp sensor and the measuring apparatus are not limited to the above configurations. For example, the example in which the engaging part is configured with four first protrusions and four or two second protrusions has been described above. However, the number of protrusions forming the engaging part is equal to the number of the above examples. It is not limited and can be defined arbitrarily.

  Further, as described above, the protrusion 33 (first protrusion) is disposed on the facing surface 31 of the clamp portion 22 and the protrusion 63 (second protrusion) is disposed on the facing surface 61 of the clamp portion 52. Alternatively, a configuration in which the protrusion 63 is disposed on the facing surface 31 and the protrusion 33 is disposed on the facing surface 61 may be employed. Further, the example in which the protrusion 133 (first protrusion) is disposed on the facing surface 131 of the clamp portion 122 and the protrusion 163 (second protrusion) is disposed on the facing surface 161 of the clamp portion 152 has been described above. Alternatively, a configuration in which the protruding portion 163 is disposed on the facing surface 131 and the protruding portion 133 is disposed on the facing surface 161 may be employed. Further, the example in which the protrusion 233 (first protrusion) is disposed on the facing surface 231 of the clamp part 222 and the protrusion 263 (second protrusion) is disposed on the facing surface 261 of the clamp part 252 has been described above. Alternatively, a configuration in which the protruding portion 263 is disposed on the facing surface 231 and the protruding portion 233 is disposed on the facing surface 261 may be employed.

  In the closed state, the configuration example in which the second protrusion is positioned between the two first protrusions has been described above. However, in the closed state, the second protrusion is outside the first protrusions (in the thickness direction A). A configuration located on the end side) can also be employed. In the closed state, a part of the plurality of second protrusions is positioned between the two first protrusions, and the other second protrusions are positioned outside the first protrusions. It can also be adopted.

  In addition, the configuration example in which one of the two clamp portions 22 and 52 is fixed (not rotated) and only the other one is rotatable is described above, but both the two clamp portions 22 and 52 can be rotated. It is also possible to adopt the configuration as follows.

  Although the example in which the detection element 71 is disposed in the clamp unit 22 has been described above, a configuration in which the detection element 71 is disposed in the clamp unit 52 or a configuration in which the detection element 71 is disposed in both the clamp unit 22 and the clamp unit 52 is described. It can also be adopted.

  In addition, although the configuration example using the Hall element as the detection element 71 has been described above, a configuration using a magnetic detection element such as a magnetoresistive effect element, a magnetic impedance element, or a fluxgate sensor as the detection element 71 may be employed.

  Further, as an example of the measuring device, the current measuring device 1 that measures the current as the measured amount based on the detected amount detected by the clamp sensor 3 has been described as an example, but the current is detected by the clamp sensor 3. The present invention can also be applied to a measuring device that measures other physical quantities (for example, resistance or power) based on the detected amount.

DESCRIPTION OF SYMBOLS 1 Current measuring device 2a Measuring part 3,103,203 Clamp sensor 22,52,122,152,222,252 Clamping part 22a, 52a, 122a, 152a, 222a, 252a Tip part 22b, 52b Base end part 31,61, 131, 161, 231, 261 Opposing surfaces 31a, 61a, 131a, 161a, 231a, 261a End portions 31b, 61b, 131b, 161b, 231b, 261b Central portions 32, 132, 232, 62, 162, 262 Engaging portions 33a ~ 33d, 133a ~ 133d, 233a ~ 233d Protrusion 63a ~ 63d, 163a, 163b, 263a, 263b Protrusion 300 Annular body 301 Central axis 302 Straight line 400 Electric wire A Thickness direction B Rotation direction

Claims (6)

A pair of clamp portions that are each formed in an arc shape in plan view and at least one of which is configured to be rotatable around the base end portion side, and that constitutes an annular body that surrounds the clamp target in a closed state in which each distal end portion is closed, A clamp sensor comprising:
In the closed state, the clamp portions are provided with opposing surfaces that are opposed to each other in the closed state, and are disposed so as to protrude from the opposing surfaces, and are engaged with each other in the closed state. It is configured to include an engaging portion that restricts movement of the tip portions in the thickness direction of each clamp portion and separates the opposing surfaces from each other.
Each of the opposing surfaces has an external force in a rotational direction about a straight line along a direction connecting the distal end portion and the proximal end portion of each clamp portion in the annular body on each clamp portion in the closed state. Formed to be parallel to each other when not acting,
The engaging portion is disposed at a position excluding both end portions in the thickness direction on the opposing surfaces, and an external force in the rotating direction acts on the clamp portions in the closed state so that the opposing surfaces are Clamp sensor that constitutes a fulcrum when rotating.   The engaging portions are arranged on either one of the opposing surfaces so as to be spaced apart from each other, and the engaging portions are provided on the other opposing surface and each of the first protrusions in the closed state. The clamp sensor according to claim 1, further comprising a second projecting portion positioned between the one projecting portions. Each said 1st projection part is arrange | positioned in the position except the center part of the said thickness direction in any one said opposing surface,
The clamp sensor according to claim 2, wherein the second protrusion is disposed at a position excluding a central portion in the thickness direction on the other facing surface. Each said 1st projection part is arrange | positioned in the position except the center part of the said thickness direction in any one said opposing surface,
The clamp sensor according to claim 2, wherein the second projecting portion is disposed at a central portion in the thickness direction on the other facing surface.   The clamp sensor according to claim 4, wherein the second projecting portion is configured such that a tip portion thereof is separated from any one of the opposing surfaces in the closed state.   6. A measuring apparatus comprising: the clamp sensor according to claim 1; and a measuring unit that measures a measured amount of the clamp target based on a detected amount detected by the clamp sensor.

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