CN111742230B - Clamp type sensor and measuring device - Google Patents

Abstract

The clamping object is reliably clamped. The clamp comprises a pair of clamp arms (11 a), wherein the clamp arms are respectively formed into an approximate arc shape in a top view, at least one of the clamp arms is configured to be capable of rotating to enable the front end parts to be mutually opened and closed, an annular body is formed under the state that the front end parts are mutually closed, each part (51 a) on the front end part side of each clamp arm is provided with a pair of opposite surfaces (101) forming the outer peripheral surface and the inner peripheral surface of the annular body, a pair of opposite surfaces (102) forming two side surfaces of the annular body, a pair of opposite surfaces (103) inclined relative to the opposite surfaces (101, 102) and a pair of opposite surfaces (104) inclined relative to the opposite surfaces (101, 102), and each part on the front end part side of each clamp arm is formed as follows: of the sides constituting the outer shape of the cross section (Sc 1) orthogonal to the longitudinal direction of each clamp arm, the length (L2) of the sides (E3, E4) corresponding to the opposing surfaces (103, 104) is longer than the length (L1) of the sides (E1, E2) corresponding to the opposing surfaces (101, 102).

Description

Clamp type sensor and measuring device

Technical Field

The present invention relates to a clamp sensor for detecting a detected amount of a clamp object in a state in which the clamp object is clamped by a pair of clamp arms having an approximately arc shape in a plan view, and a measuring device including the clamp sensor for measuring the detected amount of the clamp object.

Background

As such a clamp sensor, a clamp sensor disclosed in patent document 1 described below by the applicant is known. The clamp sensor includes a movable sensor and a fixed sensor each formed in a substantially circular arc shape in plan view. In this case, the movable sensor is coupled to be rotatable about the base end portion by the base end portion being inserted through the coupling pin. When detecting a current flowing through an electric wire, for example, using the clamp sensor, a control lever provided at a base end portion of the movable side sensor is held. At this time, the movable-side sensor rotates, and the tip ends of the sensors face away from each other. Then, the electric wire is passed through the divided portion, and then the grip state of the control lever is released. At this time, the tip ends of the sensors are brought into contact with each other by the urging force of the springs, and the electric wire is surrounded by the annular body formed by the sensors and clamped. Then, the current flowing through the electric wire is detected by each sensor.

Prior art literature

Non-patent literature

Patent document 1: japanese patent laid-open No. 2007-17188 (pages 4-5, FIG. 1)

Disclosure of Invention

Technical problem to be solved by the invention

However, the above-described clamp sensor has the following problems that need to be improved. That is, in such a clamp sensor including the clamp sensor described above, in order to secure sufficient sensitivity, each sensor is formed thicker, and a cross section of each sensor is formed in a substantially square shape. Therefore, the clamp sensor has the following technical problems: when another wire is disposed near the wire of the detection object or an obstacle is present near the wire of the detection object, it is difficult to insert the tip end portion of each sensor into a gap between the wire of the detection object and the other wire or the obstacle, and therefore the wire of the detection object cannot be clamped by each sensor, which is desired to be improved.

The present invention has been made in view of the above-described problems to be improved, and a main object thereof is to provide a clamp sensor and a measuring device capable of reliably clamping a clamping object.

Technical proposal adopted for solving the technical problems

In order to achieve the above object, a clamp sensor according to a first aspect includes a pair of clamp arms each formed in an approximately arc shape in a plan view, at least one of the pair of clamp arms being configured to be rotatable to open and close each of front end portions of the pair of clamp arms to each other, such that the pair of clamp arms form a ring-shaped body in a state where the front end portions are closed to each other, the clamp sensor being configured to be capable of detecting a detected amount of a clamp object in a state where the clamp object is clamped by each of the clamp arms,

Each portion of the tip portion side of each of the clamp arms has a pair of first opposing faces that constitute an outer peripheral face and an inner peripheral face of the annular body, a pair of second opposing faces that constitute both side faces of the annular body, and a plurality of third opposing faces that are inclined with respect to each of the first opposing faces and each of the second opposing faces, each portion of the tip portion side of each of the clamp arms being formed as: the length of a line segment connecting both ends of at least one of the sides corresponding to the third opposing faces is longer than the shortest length of the sides corresponding to the first opposing faces and the second opposing faces among the sides constituting the outer shape of the cross section orthogonal to the longitudinal direction of the clamping arms.

In the clamp sensor according to the second aspect, the clamp sensor according to the first aspect is characterized in that each position on the distal end portion side of each clamp arm is formed as: all the line segments connecting the respective ends of the respective sides corresponding to the respective third opposing faces are longer than the shortest length among the lengths of the respective sides corresponding to the respective first opposing faces and the respective second opposing faces.

Further, according to a third aspect, there is provided a clamp sensor including a pair of clamp arms each formed in an approximately arc shape in a plan view, at least one of the pair of clamp arms being configured to be rotatable to open and close each of front end portions of the pair of clamp arms to each other, the clamp arms forming a ring-shaped body in a state where the front end portions are closed to each other, the clamp sensor being configured to be capable of detecting a detected amount of a clamping object in a state where the clamping object is clamped by each of the clamp arms,

each portion of the tip portion side of each of the clamp arms has a pair of first opposing faces that constitute an outer peripheral face and an inner peripheral face of the annular body, a pair of second opposing faces that constitute both side faces of the annular body, and a plurality of third opposing faces that are inclined with respect to each of the first opposing faces and each of the second opposing faces, each portion of the tip portion side of each of the clamp arms being formed as: among the sides constituting the outer shape of the cross section orthogonal to the longitudinal direction of each of the clamp arms, the relative distance between a line segment connecting both end portions of one of the sides corresponding to each of the third opposite sides and facing each other and a line segment connecting both end portions of the other of the sides is within the following range: and (100/. V.2)% greater than any shorter distance of the respective sides corresponding to the respective first opposite faces and the respective sides corresponding to the respective second opposite faces, and 110% or less of the any shorter distance.

In the clamp sensor according to the fourth aspect, the clamp arm is formed with a pair of clamp arms having a pair of end portions, each of the clamp arms having a pair of end portions, and each of the clamp arms has a pair of end portions: the relative distances of all combinations of the sides that are opposite to each other lie within the following ranges: is greater than (100/. V.2)% of any shorter distance of the relative distances of the sides corresponding to the first opposite faces and the relative distances of the sides corresponding to the second opposite faces, and is 110% or less of the any shorter distance.

Further, a fifth aspect of the present invention provides a clamp sensor including a pair of clamp arms each formed in an approximately arc shape in a plan view, at least one of the pair of clamp arms being configured to be rotatable to open and close each of front end portions of the pair of clamp arms to each other, such that the pair of clamp arms form a ring-shaped body in a state where the front end portions are closed to each other, the clamp sensor being configured to be capable of detecting a detected amount of a clamping object in a state where the clamping object is clamped by each of the clamp arms,

each portion of the tip portion side of each of the clamp arms has a pair of first opposing faces that constitute an outer peripheral face and an inner peripheral face of the annular body, a pair of second opposing faces that constitute both side faces of the annular body, and a plurality of third opposing faces that are inclined with respect to each of the first opposing faces and each of the second opposing faces, each portion of the tip portion side of each of the clamp arms being formed as: the length of a line segment connecting both ends of at least one of the sides corresponding to each of the third facing surfaces among the sides constituting the outer shape of the cross section orthogonal to the longitudinal direction of each of the clamp arms is within the following range: 57% or more of the shortest length among the lengths of the sides respectively corresponding to the first opposing faces and the second opposing faces, and less than 1000% of the shortest length.

In the clamp sensor according to the fifth aspect, in the clamp sensor according to the sixth aspect, each position of the tip end portion side of each of the clamp arms is formed as: the lengths of all the line segments connected with the respective two ends of the sides respectively corresponding to the third opposite sides are within the following ranges: 57% or more of the shortest length among the lengths of the sides respectively corresponding to the first opposing faces and the second opposing faces, and less than 1000% of the shortest length.

Further, according to a seventh aspect, there is provided a clamp sensor including a pair of clamp arms each formed in an approximately arc shape in a plan view, at least one of the pair of clamp arms being configured to be rotatable to open and close each of front end portions of the pair of clamp arms to each other, the clamp arms forming a ring-shaped body in a state where the front end portions are closed to each other, the clamp sensor being configured to be capable of detecting a detected amount of a clamping object in a state where the clamping object is clamped by each of the clamp arms,

each portion of each of the clamp arms on the tip end side has a pair of first opposing faces that constitute an outer peripheral face and an inner peripheral face of the annular body, and a pair of second opposing faces that constitute both side faces of the annular body, each portion of each of the clamp arms on the tip end side being formed as: of the sides constituting the outer shape of the cross section orthogonal to the longitudinal direction of each of the clamp arms, the sides corresponding to each of the first opposing faces are formed as straight lines, and the sides corresponding to each of the second opposing faces are formed as curved lines curving outward.

In the clamp sensor according to the eighth aspect, the clamp sensor according to the seventh aspect is characterized in that each position on the distal end portion side of each of the clamp arms is formed as: the longest relative length of each side corresponding to each second opposing face along a direction perpendicular to the opening face of the annular body is equal to or less than the relative distance of each side corresponding to each first opposing face.

Further, a clamp sensor according to a ninth aspect includes a pair of clamp arms each formed in an approximately arc shape in a plan view, at least one of the pair of clamp arms being configured to be rotatable to open and close each of front end portions of the pair of clamp arms to each other, so that the pair of clamp arms form a ring-shaped body in a state where the front end portions are closed to each other, the clamp sensor being configured to be capable of detecting a detected amount of a clamping object in a state where the clamping object is clamped by each of the clamp arms,

each portion of the tip portion side of each of the clamp arms has a pair of first opposing faces that constitute an outer peripheral face and an inner peripheral face of the annular body, a pair of second opposing faces that constitute two side faces of the annular body, and two pairs of fourth opposing faces that are located between each of the first opposing faces and each of the second opposing faces, each portion of the tip portion side of each of the clamp arms being formed as: of the sides constituting the outer shape of the cross section orthogonal to the longitudinal direction of each of the clamp arms, the sides corresponding to each of the first opposing faces and the sides corresponding to each of the second opposing faces are formed as straight lines, and the sides corresponding to each of the fourth opposing faces are formed as curved lines curving outward.

In the clamp sensor according to a tenth aspect, the clamp sensor according to the ninth aspect is characterized in that each position on the distal end portion side of each of the clamp arms is formed as: the relative distance between the sides corresponding to the second opposite faces is equal to or less than the relative distance between the sides corresponding to the first opposite faces.

Further, in the clamp sensor according to an eleventh aspect, in the clamp sensor according to any one of claims one to ten, each of the clamp arms includes a sensor housing constituting a housing of each of the clamp arms, each of the sensor housings is formed as: the thickness of each portion corresponding to the front end portion side of each of the clamp arms is uniform or substantially uniform in a state of being observed at the cut surface.

Further, on the basis of the clamp sensor according to any one of claims one to eleven, in the clamp sensor according to claim twelve, each of the clamp arms is formed as: the cross-sectional area of each portion on the base end side of each of the clamp arms is larger than the cross-sectional area of each portion on the tip end side.

Further, in the clamp sensor according to a thirteenth aspect, in the clamp sensor according to the twelfth aspect, each of the clamp arms includes a core that generates a magnetic field by a current flowing through the clamp object, and is formed as: on a straight line passing through a centroid of a graph of a ring-shaped magnetic circuit formed by each core in a planar view of a top portion of the ring-shaped body corresponding to each tip portion and in a state where the ring-shaped body is formed, a plane passing through an arbitrary point in a range of a length corresponding to 40% of a straight line distance from the top portion to the centroid with the centroid as a center and orthogonal to the straight line is defined as a boundary surface, and an area of an outline of the cross section at a portion between the boundary surface and the tip portion as each portion on the tip portion side is smaller than an area of an outline of the cross section at a portion between the boundary surface and the base portion as each portion on the base portion side.

In addition, on the basis of the clamp sensor according to claim twelve, in the clamp sensor according to claim fourteen, each of the clamp arms is formed as: on a straight line passing through a center of a graph in a plan view of a top portion of the annular body and an inner periphery of the annular body corresponding to each of the tip portions, a plane orthogonal to the straight line and passing through an arbitrary point in a range of 40% of a length of a straight line distance from the top portion to the center of the graph, which is centered on the center of the graph, is defined as a boundary surface, and an area of an outer shape of the cross section at a portion between the boundary surface and the tip portion, which is each portion on the tip portion side, is smaller than an area of an outer shape of the cross section at a portion between the boundary surface and the base portion, which is each portion on the base portion side.

Further, on the basis of the clamp sensor according to any one of claims one to fourteen, in the clamp sensor according to claim fifteen, each of the clamp arms is formed as: the first opposing surfaces of the outer peripheral surfaces of the tip portions of the clamp arms are formed as a plane orthogonal to a direction connecting the tip portion and the base portion of the annular body in a state in which the annular body is formed, and a relative distance between the first opposing surfaces of the tip portions of the clamp arms is shorter than a relative distance between the first opposing surfaces of the clamp arms at other portions than the tip portions.

Further, on the basis of the clamp sensor according to any one of claims one to fifteen, in the clamp sensor according to claim sixteen, each of the clamp arms is formed as: a length along the straight line between a position separated from the center of the top by 15mm along a direction orthogonal to the straight line and parallel to the opening surface of the annular body and the outer peripheral surface of the annular body is in a range of 9mm to 11 mm.

Further, in the clamp sensor according to any one of claims one to sixteen, in the seventeenth aspect, each of the clamp arms is formed as: the longest distance of the straight line distances between any two points in the outer shape of the cross section at a position between the boundary surface and the front end portion side is in a range of 1/6 to 1/5 of a separation distance between the front end portions of the respective clamp arms in a state where the front end portions are separated from each other most.

The measuring device according to the eighteenth aspect includes: a clamp sensor according to any one of claims one to seventeen; and a measuring unit that measures a measured amount of the clamping object based on the measured amount detected by the clamp sensor.

Effects of the invention

In the clamp sensor according to the first aspect and the measuring device according to the eighth aspect, each position on the distal end portion side of each clamp arm is formed as: the length of a line segment connecting both ends of at least one of the sides corresponding to the third opposing faces is longer than the shortest length of the sides corresponding to the first opposing faces and the second opposing faces. Therefore, in the clamp sensor and the measuring device, the relative distance between the sides corresponding to the third opposing surfaces can be made shorter than the relative distance between the sides corresponding to the first opposing surfaces and the relative distance between the sides corresponding to the second opposing surfaces. As a result, according to the clamp sensor and the measuring device, the tip end portions of the clamp arms can be easily inserted into the narrow gaps in a state where the measuring device is tilted, compared with a conventional structure (a structure in which the corners of the quadrangular prism are not chamfered) in which the outer shape of the cross section of each portion on the tip end portion side of the clamp arms is quadrangular and the diagonal distance of the cross section is longer than the relative distance of each side corresponding to each first opposing surface and the relative distance of each side corresponding to each second opposing surface. Therefore, according to the clamp sensor and the measuring device, for example, even when another conductor or an obstacle exists in the vicinity of the conductor to be clamped, the conductor to be clamped can be reliably clamped.

In the clamp sensor according to the second aspect and the measuring device according to the tenth aspect, since the parts on the distal end side of the clamp arms are formed such that the lengths of all the line segments connected to the respective ends of the sides corresponding to the third opposing faces are longer than the shortest length of the sides corresponding to the first opposing faces and the second opposing faces, the relative distances of the sides corresponding to the third opposing faces can be made shorter than the relative distances of the sides corresponding to the first opposing faces and the relative distances corresponding to the second opposing faces. Therefore, for example, even in a state where the measuring device is tilted so as to rotate in either one of the right-hand rotation and the left-hand rotation about the longitudinal direction of the measuring device, the tip ends of the clamp arms can be easily inserted into the narrow gap.

In the clamp sensor according to the third aspect and the measuring device according to the eighth aspect, the relative distance between the line segment connecting the two ends of one of the sides corresponding to the third opposing surfaces and the line segment connecting the two ends of the other of the sides is within the following range: is greater than (100/. V.2)% of any shorter distance of the relative distances of the sides corresponding to the first opposite faces and the relative distances of the sides corresponding to the second opposite faces, and is 110% or less of the any shorter distance. Therefore, in the clamp sensor and the measuring device, the relative distance corresponding to each third facing surface can be made sufficiently shorter than the diagonal distance of the cross section in the conventional structure (structure in which the corners of the quadrangular prism are not chamfered) formed in such a manner that the outer shape of the cross section at each portion on the tip end side of each clamp arm is quadrangular. As a result, according to the clamp sensor and the measuring device, the tip ends of the clamp arms can be easily inserted into the narrow gap in a state where the measuring device is tilted, as compared with the conventional structure. Therefore, according to the clamp sensor and the measuring device, for example, even when another conductor or an obstacle exists in the vicinity of the conductor to be clamped, the conductor to be clamped can be reliably clamped.

In addition, according to the clamp sensor of the fourth aspect and the measuring device of the eighth aspect, the relative distance of all combinations of the sides where the respective portions on the tip end portion side of the respective clamp arms are formed to face each other is within the following range: the relative distance between the sides corresponding to the first opposing faces and the relative distance between the sides corresponding to the second opposing faces are larger than (100/. V.2)% of any shorter distance and are 110% or less of the any shorter distance, and therefore, all the relative distances corresponding to the third opposing faces can be made sufficiently shorter than the diagonal distance of the cross section in the conventional structure. Therefore, according to the clamp sensor and the measuring device, for example, even in a state in which the measuring device is tilted with the longitudinal direction of the measuring device as an axis and in which the measuring device is rotated in either one of the right-hand rotation and the left-hand rotation, the tip portions of the clamp arms can be easily inserted into the narrow gaps.

In the clamp sensor according to the fifth aspect and the measuring device according to the eighth aspect, the length of a line segment connecting both ends of at least one of the sides corresponding to the third opposite surfaces among the sides constituting the outline of the cross-sectional surface is set within the following range: 57% or more and less than 1000% of the shortest length of each side corresponding to each first opposing face and each second opposing face, respectively. Therefore, according to the clamp sensor and the measuring device, the relative distance between the sides corresponding to the third opposing surfaces can be made sufficiently shorter than the diagonal distance of the cross section in the conventional structure (structure in which the corners of the quadrangular prism are not chamfered) in which the outer shape of the cross section at each portion on the tip end side of each clamp arm is formed in a quadrangular shape. As a result, according to the clamp sensor and the measuring device, the tip ends of the clamp arms can be easily inserted into the narrow gap in a state where the measuring device is tilted, as compared with the conventional structure. Therefore, according to the clamp sensor and the measuring device, for example, even when another conductor or an obstacle exists in the vicinity of the conductor to be clamped, the conductor to be clamped can be reliably clamped.

In addition, according to the clamp sensor of the sixth aspect and the measuring device of the eighteenth aspect, the positions of the distal end portions of the clamp arms are formed such that the lengths of all the line segments connecting the respective ends of the sides corresponding to the respective third opposite faces are within the following ranges: by having 57% or more and less than 1000% of the shortest length of the lengths corresponding to the first and second opposing surfaces, respectively, all the relative distances of the sides corresponding to the third opposing surfaces can be made sufficiently shorter than the diagonal distance of the cross section in the conventional structure. Therefore, according to the clamp sensor and the measuring device, for example, even in a state in which the measuring device is tilted with the longitudinal direction of the measuring device as an axis and in which the measuring device is rotated in either one of the right-hand rotation and the left-hand rotation, the tip portions of the clamp arms can be easily inserted into the narrow gaps.

Further, according to the clamp sensor of the seventh aspect and the measuring device of the eighteenth aspect, since each portion on the distal end portion side of each clamp arm is formed so that each side corresponding to each first opposing surface among the sides constituting the outline of the cross section is formed as a straight line and each side corresponding to each second opposing surface is formed as a curved line curved outward, the longest relative distance of each side corresponding to each second opposing surface can be set to be equal to or smaller than the relative distance of each side corresponding to each first opposing surface, and therefore, the distal end portion of each clamp arm can be easily inserted into a narrow gap in a state where the measuring device is tilted, as compared with a conventional structure (a structure where each corner portion of each quadrangular prism is not chamfered) in which the outline of the cross section of each distal end portion side portion of the clamp arm is quadrangular and the diagonal distance of the cross section is longer than the relative distance of each side corresponding to each first opposing surface and the longest relative distance of each side corresponding to each second opposing surface. Therefore, according to the clamp sensor and the measuring device, even when another conductor or an obstacle is present in the vicinity of the conductor to be clamped, the conductor to be clamped can be reliably clamped.

In the clamp sensor according to the eighth aspect and the measuring device according to the tenth aspect, each position on the distal end portion side of each clamp arm is formed such that the longest relative distance between each side corresponding to each second opposing surface in the direction perpendicular to the opening surface of the annular body is equal to or less than the relative distance between each side corresponding to each first opposing surface. Therefore, according to the clamp sensor and the measuring device, the tip end portion of the clamp arm can be more easily inserted into the narrow gap by tilting the measuring device so that the tilt angle of the opening surface of the annular body with respect to the extending direction of the conductor to be clamped becomes smaller.

In the clamp sensor according to the ninth aspect and the measuring device according to the eighteenth aspect, since the portions on the distal end side of each clamp arm are formed so that the sides corresponding to the first opposing surfaces and the sides corresponding to the second opposing surfaces are formed as straight lines and the sides corresponding to the fourth opposing surfaces are formed as curved lines curved outward, the longest relative distance of the sides corresponding to the fourth opposing surfaces can be equal to or less than the relative distance of the sides corresponding to the first opposing surfaces, and therefore, the distal end of each clamp arm can be easily inserted into a narrow gap in a state where the measuring device is tilted, as compared with a conventional structure (structure in which the corners of the four corners are not chamfered) in which the sides corresponding to the first opposing surfaces and the sides corresponding to the fourth opposing surfaces are formed as a square shape and the diagonal distance of the cross section is longer than the relative distance of the sides corresponding to the first opposing surfaces. Therefore, according to the clamp sensor and the measuring device, even when another conductor or an obstacle is present in the vicinity of the conductor to be clamped, the conductor to be clamped can be reliably clamped.

In the clamp sensor according to a tenth aspect and the measuring device according to a tenth aspect, the positions of the distal end portions of the clamp arms are formed such that the relative distances between the sides corresponding to the second opposing surfaces are equal to or less than the relative distances between the sides corresponding to the first opposing surfaces. Therefore, according to the clamp sensor and the measuring device, the tip end portion of the clamp arm can be more easily inserted into the narrow gap by tilting the measuring device so that the tilt angle of the opening surface of the annular body with respect to the extending direction of the conductor to be clamped becomes smaller.

In the clamp sensor according to the eleventh aspect and the measuring device according to the tenth aspect, each of the clamp arms is formed such that the thickness of each portion of the sensor housing constituting the housing of each of the clamp arms, which portion corresponds to the tip end side of each of the clamp arms, is uniform or substantially uniform in a state of being observed at the cut surface. Therefore, according to the clamp sensor and the measuring device, compared with a structure in which the thickness of each sensor housing is not uniform, stress concentration in a portion where the thickness of each sensor housing is thin can be avoided, so that the strength of each sensor can be improved, and further breakage of each sensor housing when a load acts on each sensor housing can be prevented.

In addition, according to the clamp sensor of the twelfth aspect and the measuring device of the eighteenth aspect, the clamp arms are formed such that the cross-sectional area of each portion on the base end portion side of the clamp arms is larger than the cross-sectional area of each portion on the tip end portion side, whereby the strength of the clamp arms can be sufficiently improved as compared with a structure in which the clamp arms are formed such that the cross-sectional area of each portion on the tip end portion side is the same as the cross-sectional area of each portion on the base end portion side.

In the clamp sensor according to the thirteenth aspect and the measuring device according to the eighteenth aspect, each of the clamp arms is formed such that an area of an outline of a cross section at a portion between the boundary surface and the tip portion is smaller than an area of an outline of a cross section at a portion between the boundary surface and the base portion, wherein the boundary surface passes through a point in a range of a length of 40% of a straight line distance from the top portion to the center of the line passing through a top portion of the annular body and a center of the magnetic path in a plan view. In this case, when a surface passing through a point which is closer to the top than a length corresponding to 40% is defined as a boundary surface, the length of a portion on the side of the tip portion having a small area (i.e., thin) is short, and when one of a plurality of clamping objects arranged side by side at a narrow interval is clamped, it is difficult to insert the tip portion of each clamping arm into the back side of a narrow gap between adjacent clamping objects. On the other hand, when the surface passing through the point closer to the base end portion beyond the range corresponding to 40% of the length is defined as the boundary surface, the length of the portion on the side of the base end portion having a large area (i.e., thick) is short, and the strength of each clamp arm is lowered. In contrast, in this clamp sensor and measuring device, since the surface passing through the point defined within the range corresponding to 40% of the length is defined as the boundary surface, the tip portions of the clamp arms can be easily inserted into the inner side of the narrow gap between the adjacent clamp objects without decreasing the strength of the clamp arms. Therefore, according to the clamp sensor and the measuring device, the clamping object can be reliably clamped.

In the clamp sensor according to a fourteenth aspect and the measuring device according to a seventeenth aspect, each of the clamp arms is formed such that an area of an outline of a cross section at a portion between the boundary surface and the tip portion is smaller than an area of an outline of a cross section at a portion between the boundary surface and the base portion, wherein the boundary surface passes through a point in a range of 40% of a length of a straight line distance from the top portion to the center of the line passing through a top portion of the annular body and an inner periphery of the annular body in a plan view. In this case, when a surface passing through a point which is closer to the top than a length corresponding to 40% is defined as a boundary surface, the length of a portion on the side of the tip portion having a small area (i.e., thin) is short, and when one of a plurality of clamping objects arranged side by side at a narrow interval is clamped, it is difficult to insert the tip portion of each clamping arm into the back side of a narrow gap between adjacent clamping objects. On the other hand, when a surface passing through a point which is beyond a range corresponding to 40% of the length and is close to the base end is defined as a boundary surface, the length of the portion on the base end side having a large area (i.e., thick) is short, and the strength of each clamp arm is lowered. In contrast, in this clamp sensor and measuring device, since the surface passing through the point defined within the range corresponding to 40% of the length is defined as the boundary surface, the tip portions of the clamp arms can be easily inserted into the inner side of the narrow gap between the adjacent clamp objects without decreasing the strength of the clamp arms. Therefore, according to the clamp sensor and the measuring device, the clamping object can be reliably clamped.

In the clamp sensor according to the fifteenth aspect and the measuring device according to the eighteenth aspect, each of the clamp arms is formed as: the first opposing surfaces of the outer peripheral surface of the annular body constituting the distal end portions of the clamp arms are formed as a single plane orthogonal to the direction connecting the distal end portions and the base end portions of the annular body in the shape state of the annular body, and the relative distance of the first opposing surfaces at the distal end portions is shorter than the relative distance of the first opposing surfaces at other portions of the clamp arms than the distal end portions. Therefore, according to the clamp sensor and the measuring device, the tip portions of the clamp arms can be more easily inserted into the narrow gap. Further, since the relative distance of the first opposing faces at the respective front end portions is short, for example, even in the case where an obstacle such as a wall exists behind the clamping object and the gap between the clamping object and the obstacle is narrow, the obstacle can be prevented from contacting the respective clamping arms, thereby reliably clamping the clamping object.

In the clamp sensor according to a sixteenth aspect and the measuring device according to a eighteenth aspect, each of the clamp arms is formed as: the length along the straight line between a position separated by 15mm from the center of the top portion along a direction orthogonal to the straight line passing through the top portion and the center of the drawing center of the annular body and parallel to the opening surface of the annular body and the outer peripheral surface of the annular body is in a range of 9mm to 11 mm. In this case, when the clamp arms are formed so that the length is greater than 11mm, the shape of the tip end portion side of each clamp arm is excessively slender, and for example, when it is desired to clamp a clamp object disposed in the vicinity of the wall surface with each clamp arm, each tip end portion of each clamp arm may come into contact with the wall surface, and clamping may become difficult. Further, when each of the clamp arms is formed so that the length is greater than 11mm, the top side of the annular body is formed in an abnormally elongated shape, and the detection characteristics of the detected amount may be deteriorated. On the other hand, when each of the clamp arms is formed so that the length is smaller than 9mm, the shape of the tip end side of each of the clamp arms is close to an arc, and for example, when one of the plurality of closely arranged clamp objects is to be clamped by each of the clamp arms, it is difficult to insert each of the tip ends into a gap between the one clamp object and the adjacent other clamp object, and there is a possibility that clamping becomes difficult. In contrast, according to the clamp sensor and the measuring device, the clamp arms are formed so that the length is 9mm to 11mm, so that the detection characteristic of the magnetic field can be maintained well and the object to be clamped can be clamped more reliably.

In the clamp sensor according to the seventeenth aspect and the measuring device according to the eighteenth aspect, the maximum distance between any two points in the profile of the cross section at the portion between the boundary surface and the distal end portion side is within a range of 1/6 to 1/5 of the separation distance between the distal end portions of the clamp arms in a state where the distal end portions are separated from each other the maximum. In this case, when the clamp arms are formed so that the ratio is greater than 1/5, it is difficult to insert the tip ends of the clamp arms into the narrow gaps between the adjacent clamp objects when clamping one of the plurality of clamp objects arranged side by side at the narrow intervals. On the other hand, when the clamp arms are formed such that the ratio is less than 1/6, if the lever for opening the clamp arms (separating the distal ends from each other) is pushed in to the greatest extent, the separation distance in the state where the distal ends are separated from each other the greatest is excessively long, and when the plurality of clamp objects are arranged at a narrow interval, the plurality of clamp objects may be clamped, and therefore, it is necessary to adjust the push-in amount of the lever, and the operability may be deteriorated. In contrast, according to the clamp sensor and the measuring device, the clamp arms are formed with the relative distance in the range of 1/6 to 1/5 of the separation distance, and the tip ends can be easily inserted into the narrow gap between the adjacent clamp objects in the state where the lever is pressed in to the maximum extent, so that the operability can be sufficiently improved, and only one of the plurality of clamp objects can be clamped more reliably.

Drawings

Fig. 1 is a perspective view of the clamp meter 1.

Fig. 2 is a structural view showing the structure of the clamp meter 1.

Fig. 3 is a perspective view of the clamp meter 1 in the open state of the clamp sensor 2.

Fig. 4 is a front view of the clamp meter 1.

Fig. 5 is a schematic front view of the clamp-on meter 1 in a state where the sensor housings 10a and 10b, a part of the main body housing 30, and the like are removed.

Fig. 6 is a cross-sectional view comparing the A-A line section and the B-B line section of fig. 4.

Fig. 7 is a sectional view taken along line A-A in fig. 4.

Fig. 8 is an explanatory diagram illustrating the structure of the clamp arms 11a and 11 b.

Fig. 9 is a front view of the clamp meter 1 in a state where the clamp arms 11a, 11b are opened.

Fig. 10 is a first explanatory diagram for explaining a method of using the clamp meter 1.

Fig. 11 is a second explanatory diagram for explaining a method of using the clamp meter 1.

Fig. 12 is a third explanatory diagram for explaining a method of using the clamp meter 1.

Fig. 13 is a front view of the clamp meter 1A.

Fig. 14 is a cross-sectional view showing the structure of the clamp sensor 402.

Fig. 15 is a cross-sectional view showing the structure of the clamp sensor 502.

Fig. 16 is a cross-sectional view showing the structure of the clamp sensor 602.

Detailed Description

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

First, the structure of the clamp-on table 1 shown in fig. 1 will be described. The clamp meter 1 is an example of a measuring device, and is configured to be able to measure a current (an example of a measured amount) flowing through a conductor 400 to be clamped, for example, as shown in fig. 10, in a non-contact (metal non-contact) manner. Specifically, as shown in fig. 1 to 3, the clamp meter 1 includes a clamp sensor 2 and a body 3.

As shown in fig. 1 and 3, the clamp sensor 2 includes a pair of clamp arms 11a and 11b (hereinafter, also referred to as "clamp arms 11" when they are not distinguished), and detects a magnetic field, which is a detection amount generated when a current flows through the conductor 400, in a noncontact manner in a state in which the conductor 400 is clamped (surrounded) by the clamp arms 11a and 11b, as shown in fig. 4.

In the clamp sensor 2, as shown in fig. 1 and 3, the clamp arm 11b (one of the clamp arms 11a and 11 b) is rotatable about the rotation shaft 23 (see fig. 4) so that the tip ends 21a and 21b of the clamp arms 11a and 11b are opened and closed (contact and separation) with each other, and the clamp arm 11a is fixed to the main body case 30 of the main body 3 in a non-rotatable state. In the clamp sensor 2, the clamp arm 11b is configured to be rotated in response to an operation (press-in or press-out release) performed on the control lever 30a disposed in the main body case 30. In the following description, a state in which the distal ends 21a, 21b of the clamp arms 11a, 11b are closed (a state shown in fig. 1) is also referred to as a "closed state", and a state in which the distal ends 21a, 21b are open (a state shown in fig. 3, 9) is also referred to as an "open state".

As shown in fig. 4, the clamp arm 11a includes a sensor housing 10a, a core 41 (see fig. 5 and 7) housed in the sensor housing 10a, and a magnetic detection element (hall element, as an example) outside the drawing. As shown in fig. 4, the clamp arm 11b includes a sensor housing 10b and a core 41 (see fig. 5 and 7) accommodated in the sensor housing 10 b.

As shown in fig. 4, the clamp arms 11a and 11b are each formed in an approximately arc shape in a plan view in the thickness direction (the axial direction of the rotation shaft 23), so that the annular body 100 is formed in a closed state in which the tip portions 21a and 21b are closed to each other. In this case, as shown in the same drawing, the annular body 100 is configured such that each portion on the base end portion 22a, 22b side of the clamp arms 11a, 11b (hereinafter also referred to as "base end portion side portions 52a, 52 b") is formed in a semicircular shape in a plan view, each portion on the tip end portion 21a, 21b side of the clamp arms 11a, 11b (hereinafter also referred to as "tip end portion side portions 51a, 51 b"), the tip portion 100a (portion corresponding to the tip end portions 21a, 21 b) is formed in an elongated annular shape in an arc shape in a plan view, and the curvature of the inner peripheral surface on the tip portion 100a side is smaller than the curvature of the inner peripheral surface on the base end portion 100b side (the curvature radius of the inner peripheral surface on the tip portion 100a side is larger than the curvature of the inner peripheral surface on the base end portion 100b side).

As shown in fig. 5, the clamp arms 11a and 11b are formed in a ring-like body 100, and form a ring-like (approximately elliptical) magnetic circuit Mc through each core 41. In this case, when a current flows in the conductor 400 surrounded (clamped) by the clamp arms 11a, 11b, a magnetic field is generated in the magnetic circuit Mc due to the current, and the magnetic detection element of the clamp arm 11a detects the magnetic field.

As shown in fig. 6, the clamp arms 11a and 11B are formed, for example, in an approximately octagonal shape in the outer shape of a cross section Sc1 (for example, A-A line cross section in fig. 4) orthogonal to the longitudinal direction of the tip end portion side portions 51a and 51B, and the clamp arms 11a and 11B are formed in an approximately rectangular shape in the outer shape of a cross section Sc2 (for example, B-B line cross section in fig. 4) orthogonal to the longitudinal direction of the base end portion side portions 52a and 52B. As shown in fig. 6, in the clamp arms 11a and 11b, the area Sa1 of the outline of the cut surface Sc1 at the tip end side portions 51a and 51b is smaller than the area Sa2 of the outline of the cut surface Sc2 at the base end side portions 52a and 52b (hereinafter, when the areas Sa1 and Sa2 are not distinguished, this is also referred to as "area Sa") and the area Sa2 is larger than the area Sa 1. That is, the clamp arms 11a, 11b are formed such that the tip end portions 51a, 51b are thinner than the base end portions 52a, 52 b.

In the clamp sensor 2, the distal end portions 51a and 51b and the proximal end portions 52a and 52b are defined as follows. First, as shown in fig. 5, a straight line passing through the top 100a of the annular body 100 and the center of the graph C1 of the magnetic circuit Mc (indicated by a broken line in the same drawing) formed by the cores 41 in plan view is defined as a straight line H1. Next, a length corresponding to 40% of a distance D101 (linear distance) from the top 100a (specifically, the outer facing surface 101 of the top 100 a) to the centroid C1 is defined as a length L101, and an arbitrary point within a range of the length L101 centered on the centroid C1 on the straight line H1 is defined (hereinafter, also referred to as a "defined point P101"). In this case, in this example, a point separated from the centroid C1 toward the top 100a by a length corresponding to 17% of the distance D101 is defined as a predetermined point P101. Next, a plane orthogonal to the straight line H1 through the predetermined point P101 is defined as a boundary surface Sb1, the portions between the boundary surface Sb1 and the distal ends 21a, 21b at the clamp arms 11a, 11b are defined as distal end portion side portions 51a, 51b, and the portions between the boundary surface Sb1 and the proximal ends 22a, 22b are defined as proximal end portion side portions 52a, 52b.

As shown in fig. 1, 3, and 4, the tip end portions 51a and 51b of the clamp arms 11a and 11b each have a pair of opposing surfaces 101 (corresponding to first opposing surfaces) constituting the outer peripheral surface and the inner peripheral surface of the annular body 100, a pair of opposing surfaces 102 (corresponding to second opposing surfaces) constituting both side surfaces of the annular body 100, a pair of opposing surfaces 103 inclined with respect to the opposing surfaces 101 and 102, and a pair of opposing surfaces 104 (each corresponding to a third opposing surface, as an example of a plurality of pairs, two pairs of third opposing surfaces in total), and as shown in fig. 7, the tip end portions 51a and 51b of the clamp arms 11a and 11b are formed in an octagonal (approximately octagonal) shape in the outer shape of a cross section Sc1 (A-A line section in fig. 4) orthogonal to the longitudinal direction of the clamp arms 11a and 11 b. In other words, the distal end portions 51a and 51b of the clamp arms 11a and 11b are formed in an octagon shape in which corners of a quadrangular prism shown by a broken line in fig. 7 are chamfered (the facing surfaces 103 and 104 correspond to surfaces (chamfered surfaces) formed by chamfering). Since the cross-sectional shapes of the tip-end- side portions 51a and 51b are the same, only the cross-sectional shape of the tip-end-side portion 51a is shown in the same drawing, and the cross-sectional shape of the tip-end-side portion 51b is not shown.

As shown in fig. 7, in the clamp sensor 2, the portions of the clamp arms 11a and 11b on the distal end portions 51a and 51b excluding the distal ends 21a and 21b are formed as follows: of the sides of the octagon, which is the outline of the cut plane Sc1, each side E1 corresponding to each opposing surface 101 and each side E2 corresponding to each opposing surface 102 have the same length L1, and each side E3 corresponding to each opposing surface 103 (the length of the line segment connecting the respective both ends of each side E3) and each side E4 corresponding to each opposing surface 104 (the length of the line segment connecting the respective both ends of each side E4) have the same length L2. In addition, in the clamp sensor 2, as shown in the same drawing, the tip end side portions 51a and 51b are formed to have a length L2 longer than a length L1 (the shortest length among the lengths of the sides E1 and E2).

In the example shown in fig. 7, since the sides E3 and E4 are straight lines, the length of the line connecting the both ends of the sides E3 and E4 is the same as the length of the sides E3 and E4, but a configuration in which the sides E3 and E4 are curved (arc-shaped) (a configuration in which the outline of the cut plane Sc1 is approximately octagonal) may be adopted, in which the length of the line connecting the both ends of the sides E3 and E4 is set to be the length L2 so that the length L2 is longer than the length L1 (the shortest length among the lengths of the sides E1 and E2), the front end side portions 51a and 51b are formed.

In the clamp sensor 2, the lengths L1 of the sides E1 and E2 and the lengths L2 of the sides E3 and E4 are defined in the above manner, so that the respective tip end portions 51a and 51b are formed such that the relative distances D3 and D4 of the sides E3 and E4 are shorter than the relative distances D1 and D2 of the sides E1 and E2, as shown in fig. 7.

In the clamp sensor 2, as shown in fig. 7, the thickness T of each portion of the sensor housings 10a, 10b constituting the housing of the clamp arms 11a, 11b corresponding to each tip end portion side portion 51a, 51b (hereinafter, also referred to as "tip end portion side portion of the sensor housings 10a, 10 b") is formed to be uniform (or substantially uniform) in a state of being observed at the cut plane Sc 1.

In the caliper sensor 2, as shown in fig. 8, the outer peripheral side facing surfaces 101 (the facing surfaces 101 constituting the outer peripheral surface of the annular body 100) of the distal end portions 21a and 21b of the clamp arms 11a and 11b are formed to be a single plane orthogonal to the direction (vertical direction in the same drawing) connecting the top portion 100a and the base end portion 100b of the annular body 100 in the formed state of the annular body 100. That is, the annular body 100 is formed in a shape in which a portion (a portion shown by a broken line in the same drawing) on the outer peripheral side at the top portion 100a is cut out by a flat surface. In the clamp sensor 2, as shown in the same drawing, the relative distance D1 between the facing surfaces 101 at the distal ends 21a and 21b (hereinafter, the relative distance D1 will be referred to as "relative distance D1 a") is shorter than the relative distance D1 between the facing surfaces 101 at the other portions of the clamp arms 11a and 11b except the distal ends 21a and 21b (hereinafter, the relative distance D1 will be referred to as "relative distance D1 b"). Accordingly, in the caliper sensor 2, the length of the annular body 100 along the direction connecting the top 100a and the base end 100b is shortened in response to the shortening of the relative distance D1a between the facing surfaces 101 at the tip ends 21a and 21 b.

In the clamp sensor 2, as shown in fig. 8, the clamp arms 11a and 11b are formed so that a length L103 along a straight line H1 between a position P, which is a position separated by 15mm (hereinafter, this length is also referred to as a "length L102") from the center of the top 100a in a direction orthogonal to the straight line H1 and parallel to the opening surface F of the annular body 100, and the opposing surface 101 on the outer side of the annular body 100 is in a range of 9mm to 11 mm. That is, the clamp arms 11a, 11b are formed such that the ratio of the length L103 to the length L102 is in the range of 9/15 to 11/15.

Here, for example, when the clamp arms 11a, 11b are formed so that the length L103 is greater than 11mm, the shape of the distal ends 21a, 21b of the clamp arms 11a, 11b is too slender, and for example, when the clamp arms 11a, 11b are intended to clamp the conductor 400 disposed in the vicinity of the wall surface (the wall surface exists behind) the distal ends 21a, 21b of the clamp arms 11a, 11b are in contact with the wall surface, which may make clamping difficult. Further, when the clamp arms 11a, 11b are formed so that the length L103 is greater than 11mm, the top 100a side of the annular body 100 is formed in an abnormally elongated shape, and the detection characteristics of the magnetic field (detected amount) may be deteriorated. On the other hand, when the clamp arms 11a, 11b are formed so that the length L103 is less than 9mm, the shape of the front end portions 21a, 21b sides of the clamp arms 11a, 11b is close to an arc shape, and for example, when one conductor 400 among the plurality of conductors 400 closely arranged is intended to be clamped by the clamp arms 11a, 11b, the front end portions 21a, 21b may be difficult to be inserted into a gap between the one conductor 400 and the adjacent other conductor 400, thereby making clamping difficult. In contrast, in the clamp sensor 2, the clamp arms 11a and 11b are formed so that the length L103 along the straight line H1 between the position P, which is a position separated by 15mm from the center of the top 100a in a direction orthogonal to the straight line H1 and parallel to the opening surface F of the annular body 100, and the facing surface 101 on the outer side of the annular body 100 is in a range of 9mm to 11 mm.

In addition, in the clamp sensor 2, as shown in fig. 9, the clamp arms 11a, 11b are formed as: the longest distance among the straight-line distances between any two points in the outer shape of the cut surface Sc1 at the tip end side portions 51a, 51b is set as the relative distance D1 (see also fig. 7), and the separation distance between the tip end portions 21a, 21b in the state where the tip end portions 21a, 21b of the respective clamp arms 11a, 11b are separated from each other the greatest is set as the separation distance D102, and at this time, the ratio R of the relative distance D1 to the separation distance D102 is in the range of 1/6 to 1/5. In the clamp sensor 2, the separation distance D102 is defined to be within a range of 56.8mm±25% and the relative distance D1 is defined to be within a range of 11mm±25%, as an example.

Here, according to the experimental results of the inventors, when the clamp arms 11a, 11b are formed so that the ratio R is greater than 1/5, for example, as shown in fig. 10, when one of the plurality of conductors 400 arranged side by side at a narrow interval is clamped, it is difficult to insert the tip portions 21a, 21b of the clamp arms 11a, 11b into the narrow gaps G1, G2 between the adjacent conductors 400. On the other hand, when the clamp arms 11a, 11b are formed such that the ratio R is smaller than 1/6, the separation distance D102 in a state where the tip portions 21a, 21b are separated from each other the most, that is, in a state where the lever 30a is pressed in the greatest extent, is excessively long, and when the plurality of conductors 400 are arranged at narrow intervals, even if only one of the conductors 400 is intended to be clamped, the plurality of conductors 400 may be clamped, and therefore, it is necessary to adjust the press-in amount of the lever 30a, and the operability may be deteriorated. In contrast, in the clamp sensor 2, the clamp arms 11a and 11b are formed so that the ratio R is in the range of 1/6 to 1/5, and the tip portions 21a and 21b can be easily inserted into the narrow gaps G1 and G2 between the adjacent conductors 400 in a state where the lever 30a is pressed in to the maximum extent. Therefore, in the clamp sensor 2, it is not necessary to adjust the amount of press-in of the control lever 30a, and therefore, the operability can be sufficiently improved.

In the clamp sensor 2, as described above, the base end portions 52a and 52b of the clamp arms 11a and 11b are formed in a substantially rectangular shape in cross section, and the tip end portions 51a and 51b are thinner than the base end portions 52a and 52b as shown in fig. 4, that is, the clamp arms 11a and 11b are formed such that the area Sa1 of the outer shape of the cross section Sc1 at the tip end portions 51a and 51b is smaller than the area Sa2 of the outer shape of the cross section Sc2 at the base end portions 52a and 52b as shown in fig. 6. In other words, each of the clamp arms 11a, 11b is formed as: the base end portions 52a, 52b are thicker than the tip end portions 51a, 51b, that is, the cross section Sc2 of the base end portions 52a, 52b has a larger area than the cross section Sc1 of the tip end portions 51a, 51 b. Therefore, compared to a structure in which the clamp arms 11a, 11b are formed so that the area of the cut surface Sc1 of the distal end portions 51a, 51b is the same as the area of the cut surface Sc2 of the proximal end portions 52a, 52b, the clamp arms 11a, 11b have sufficiently improved strength in the clamp sensor 2.

In the clamp sensor 2, as described above, the portions between the boundary surface Sb1 passing through the predetermined point P101 and orthogonal to the straight line H1 and the distal ends 21a and 21b are defined as distal end portion side portions 51a and 51b, and the portions between the boundary surface Sb1 and the base ends 22a and 22b are defined as base end portion side portions 52a and 52b, wherein the predetermined point P101 is a point defined within a range of a length L101, and the length L101 is a length centered on a centroid C1 of the graph of the magnetic circuit Mc in a plan view and corresponding to 40% of a distance D101 from the top 100a to the centroid C1. In this case, when the boundary surface Sb1 is defined as a surface passing through a point beyond the range of the length L101 and approaching the top 100a, the length of the tip end side portions 51a, 51b having a small (thin) area Sa is short, and when one of the plurality of conductors 400 arranged side by side at a narrow interval is clamped, it becomes difficult to insert the tip ends 21a, 21b of the clamping arms 11a, 11b into the back side of the narrow gaps G1, G2 between the adjacent conductors 400. On the other hand, when the surface passing through the point beyond the range of the length L101 and approaching the base end portion 100b is defined as the boundary surface Sb1, the base end portion side portions 52a, 52b having a large area Sa (thick) have a short length, and the strength of the clamp arms 11a, 11b is reduced. In contrast, in the clamp sensor 2, since the surface passing through the predetermined point P101 defined within the range of the length L101 is defined as the boundary surface Sb1, the distal ends 21a, 21b of the clamp arms 11a, 11b can be easily inserted into the inner sides of the narrow gaps G1, G2 between the adjacent conductors 400 without decreasing the strength of the clamp arms 11a, 11b.

As shown in fig. 2, the main body 3 includes a main body casing 30 (see fig. 1, 3, and 4) in which the display unit 31, the operation unit 32, the processing unit 33, and the like are housed or disposed.

The display unit 31 is constituted by, for example, a liquid crystal panel, and is disposed on the front surface of the main body casing 30 as shown in fig. 1, 3, and 4. The display unit 31 displays the measured value of the current or the like under the control of the processing unit 33. The operation unit 32 includes various switches 32a and dials 32b disposed on the front surface of the main body case 30, and outputs operation signals according to the operations of these components.

The processing unit 33 controls each portion constituting the main body 3 based on the operation signal output from the operation unit 32. The processing unit 33 functions as a measuring unit that measures a current value of the current flowing through the conductor 400 based on the detection signal output from the clamp sensor 2 (magnetic detection element), and displays the current value on the display unit 31.

Next, a method of using the clamp meter 1 and an operation of the clamp meter 1 when used will be described with reference to the drawings. As an example, a description will be given of a method of using the same in a case where the current value of the current flowing through one conductor (for example, the conductor 400a shown in the same drawing) among the plurality of conductors 400 arranged side by side at a narrow interval as shown in fig. 10 is measured. In this case, in this example, a plurality of conductors 400 having a diameter of 21mm are arranged side by side at intervals of 12mm (a gap between adjacent conductors 400 is 12 mm).

First, the lever 30a (see fig. 1 and 4) of the body 3 of the clamp meter 1 is pushed in. At this time, the clamp arm 11b rotates in a direction in which the distal ends 21a, 21b of the clamp arms 11a, 11b in the clamp sensor 2 are opened against the urging force of the spring outside the drawing, and the clamp arms 11a, 11b are opened as shown in fig. 3.

Next, as shown in fig. 10, the distal ends 21a, 21b of the clamp arms 11a, 11b are brought close to the conductor 400a to be measured (to be clamped). Then, as shown in fig. 11, the clamp meter 1 is tilted by rotating the clamp meter 1 about its longitudinal direction (the direction connecting the top 110a and the base end 100b of the ring body 100 shown in fig. 4), the tip 21a of the clamp arm 11a is inserted into the gap G1 between the conductor 400b and the conductor 400a adjacent to the right side of the conductor 400a, and the tip 21b of the clamp arm 11b is inserted into the gap G2 between the conductor 400c and the conductor 400a adjacent to the left side of the conductor 400a.

Here, as shown by the broken line in fig. 7, in the conventional structure in which the outline of the cut surface Sc1 at each tip end portion side portion 51a, 51b of the clamp arms 11a, 11b is formed in a quadrangle (a structure in which each corner portion of the quadrangular prism is not chamfered), the outline of the cut surface Sc1, that is, the distance between the opposite corners in the quadrangle (the diagonal distance D5 shown in the same drawing) is longer than the relative distance D1 of each side E1 and the relative distance D2 of each side E2. Therefore, in the conventional structure, as shown in fig. 11, when the gap G1 between the conductors 400a and 400b and the gap G2 between the conductors 400a and 400c are narrow, it is difficult to insert the distal ends 21a, 21b of the clamp arms 11a, 11b into the respective gaps G1, G2 when the clamp meter 1 is tilted.

In contrast, in the clamp sensor 2, as described above, the distal end portions 51a and 51b of the clamp arms 11a and 11b are formed in an octagon-shaped prism shape in which the outer shape of the cross section Sc1 is octagon-shaped by chamfering the corners of the quadrangular prism, and the lengths L2 of the octagonal sides E3 and E4, which are the outer shape of the cross section Sc1, are longer than the lengths L1 of the sides E1 and E2. Therefore, in the clamp sensor 2, the relative distance D3 of each side E3 and the relative distance D4 of each side E4 are shorter than the relative distance D1 of each side E1 and the relative distance D2 of each side E2. Therefore, in the clamp sensor 2, the distal ends 21a and 21b of the clamp arms 11a and 11b can be easily inserted into the narrow gaps G1 and G2 in a state where the clamp meter 1 is inclined, as compared with the conventional structure.

In the clamp sensor 2, since the clamp arms 11a and 11b are formed such that the ratio R of the relative distance D1 between any two points in the outer shape of the cut plane Sc1 at the tip end side portions 51a and 51b is 1/6 or more and 1/5 or less as described above, the tip ends 21a and 21b can be easily inserted into the narrow gaps G1 and G2 between the adjacent conductors 400 in a state where the lever 30a is pressed in to the maximum extent, and the separation distance D102 is the separation distance between the tip ends 21a and 21b in a state where the tip ends 21a and 21b of the clamp arms 11a and 11b are separated from each other the maximum. Therefore, in the clamp sensor 2, it is not necessary to adjust the amount of press-in of the control lever 30a, and therefore, the operability can be sufficiently improved.

Next, the pressing of the control lever 30a is released in a state where the distal ends 21a, 21b of the clamp arms 11a, 11b are inserted into the gaps G1, G2, respectively. At this time, the clamp arm 11b is rotated in a direction in which the tip ends 21a, 21b of the clamp arms 11a, 11b contact each other by the urging force of the springs outside the drawing, so that the clamp arms 11a, 11b are brought into a closed state as shown in fig. 12. Thereby, as shown in the same drawing, the conductor 400a is clamped by the clamping arms 11a, 11 b.

In this case, in the caliper sensor 2, as described above, the respective clamp arms 11a, 11b are formed as follows: the portion between the boundary surface Sb1 passing through the predetermined point P101 defined within the length L101 and the base ends 22a, 22b of the clamp arms 11a, 11b is defined as the tip end side portions 51a, 51b, the portion between the boundary surface Sb1 and the base ends 22a, 22b of the clamp arms 11a, 11b is defined as the base end side portions 52a, 52b, and the area Sa1 of the outer shape of the cut surface Sc1 at the tip end side portions 51a, 51b is smaller than the area Sa2 of the outer shape of the cut surface Sc2 of the base end side portions 52a, 52b, wherein the length L101 is a length corresponding to 40% of the distance D101 from the top 100a to the center of the figure of the magnetic circuit Mc in a plan view. Therefore, in the clamp sensor 2, the distal ends 21a and 21b of the clamp arms 11a and 11b can be easily inserted into the inner sides of the narrow gaps G1 and G2 between the adjacent conductors 400 without reducing the strength of the clamp arms 11a and 11 b. Therefore, in the clamp sensor 2, the conductor 400a can be reliably clamped.

Next, the magnetic detection element disposed in the clamp arm 11a detects a magnetic field generated in each core of the clamp arms 11a and 11b by a current flowing through the conductor 400a, and outputs a detection signal. In this case, in the clamp sensor 2, as described above, the clamp arms 11a and 11b are formed so that the length L103 along the straight line H1 between the position P, which is a position separated by 15mm from the center of the top 100a in the direction orthogonal to the straight line H1 and parallel to the opening surface F of the annular body 100, and the facing surface 101 on the outer side of the annular body 100 is in the range of 9mm to 11 mm. Therefore, in the clamp sensor 2, the detection characteristic of the magnetic field can be maintained well. Therefore, the clamp sensor 2 can output a detection signal capable of accurately measuring the current flowing through the conductor 400 a. Next, the processing unit 33 of the main body 3 measures the current value of the current flowing through the conductor 400a based on the detection signal. Next, the processing unit 33 causes the display unit 31 to display the measured value.

Then, when the measurement is completed, the control lever 30a is pushed in to open the clamp arms 11a and 11b, and then the clamp sensor 2 is separated from the conductor 400 a. Then, the pressing of the control lever 30a is released, and the clamp arms 11a and 11b are brought into the closed state.

As described above, in the clamp sensor 2 and the clamp meter 1, the distal end portions 51a and 51b of the clamp arms 11a and 11b are formed such that the length L2 of each of the sides E3 and E4 (or the length L2 of the line connecting both ends of each of the sides E3 and E4) of the outline (in this example, octagon or nearly octagon) constituting the cut plane Sc1 is longer than the length L1 of each of the sides E1 and E2. Therefore, in the clamp sensor 2 and the clamp meter 1, the relative distance D3 of the sides E3 and the relative distance D4 of the sides E4 can be made shorter than the relative distance D1 of the sides E1 and the relative distance D2 of the sides E2. As a result, according to the clamp sensor 2 and the clamp meter 1, the distal ends 21a and 21b of the clamp arms 11a and 11b can be easily inserted into the narrow gaps G1 and G2 in a state where the clamp meter 1 is inclined, as compared with the conventional result (a structure in which the corners of the quadrangular prism are not chamfered) in which the outer shape of the cut surface Sc1 of the distal end portions 51a and 51b of the clamp arms 11a and 11b is quadrangular and the diagonal distance D5 of the cut surface Sc1 is longer than the relative distance D1 of the sides E1 and the relative distance D2 of the sides E2. Therefore, according to the clamp sensor 2 and the clamp meter 1, even when another conductor 400 or an obstacle exists in the vicinity of the conductor 400 to be clamped, the conductor 400 to be clamped can be reliably clamped.

Further, according to the clamp sensor 2 and the clamp meter 1, the distal end portion side portions 51a and 51b of the clamp arms 11a and 11b are formed such that the length L2 of the entire sides E3 and E4 (or the length L2 of all line segments connecting both ends of the sides E3 and E4) is longer than the length L1 of the sides E1 and E2, so that both the relative distance D3 of the sides E3 and the relative distance D4 of the sides E4 can be made shorter than the relative distance D1 of the sides E1 and the relative distance D2 of the sides E2. Therefore, for example, even in a state in which the clamp meter 1 is rotated in any one of the right and left rotational directions about the longitudinal direction of the clamp meter 1 to be inclined, the distal ends 21a, 21b of the clamp arms 11a, 11b can be easily inserted into the narrow gaps G1, G2.

In the clamp sensor 2 and the clamp meter 1, the clamp arms 11a and 11b are formed such that the thickness T of the portion on the distal end side of the sensor cases 10a and 10b constituting the outer shells of the clamp arms 11a and 11b is uniform (or substantially uniform) when viewed in the cut plane Sc 1. Therefore, according to the clamp sensor 2 and the clamp meter 1, compared with the structure in which the thickness T of the portion on the tip end side of the sensor cases 10a, 10b is not uniform, stress concentration at the portion where the thickness T is thin in the sensor cases 10a, 10b can be avoided, and strength of the sensor cases 10a, 10b can be improved, and therefore breakage of the sensor cases 10a, 10b when the load acts on the sensor cases 10a, 10b can be reliably prevented.

Further, according to the clamp sensor 2 and the clamp meter 1, the clamp arms 11a and 11b are formed so that the cross section Sc2 of the base end portions 52a and 52b is larger than the cross section Sc1 of the tip end portions 51a and 51b, and the strength of the clamp arms 11a and 11b can be sufficiently improved as compared with a structure in which the clamp arms 11a and 11b are formed so that the cross section Sc1 of the tip end portions 51a and 51b is the same as the cross section Sc2 of the base end portions 52a and 52 b.

In the clamp sensor 2 and the clamp meter 1, the clamp arms 11a and 11b are formed such that the area Sa1 of the outer shape of the cross section Sc1 at the tip end side portions 51a and 51b between the boundary surface Sb1 and the tip ends 21a and 21b is smaller than the area Sa2 of the outer shape of the cross section Sc2 at the base end side portions 52a and 52b between the boundary surface Sb1 and the base ends 22a and 22b, the boundary surface Sb1 passing through a point within the range of the length L101 and being orthogonal to the straight line H1, and the length L101 being a length on the straight line H1 passing through the top 110a of the annular body 100 and the centroid C1 of the graph in plan view of the magnetic circuit Mc, centered on the centroid C1 and corresponding to 40% of the distance D101 from the top 100a to the centroid C1. In this case, when the boundary surface Sb1 is defined as a surface passing through a point beyond the range of the length L101 and approaching the top 100a, the length of the tip end side portions 51a, 51b having a small area Sa1 (i.e., thin) is short, and when one of the plurality of conductors 400 arranged side by side at a narrow interval is clamped, it is difficult to insert the tip ends 21a, 21b of the clamping arms 11a, 11b into the back side of the narrow gaps G1, G2 between the adjacent conductors 400. On the other hand, when the surface passing through the point beyond the range of the length L101 and approaching the base end portion 100b is defined as the boundary surface Sb1, the base end portion side portions 52a, 52b having a large area Sa2 (i.e., thick) have a short length, and the strength of the clamp arms 11a, 11b is reduced. In contrast, in the clamp sensor 2, since the surface passing through the predetermined point P101 defined within the range of the length L101 is defined as the boundary surface Sb1, the distal ends 21a, 21b of the clamp arms 11a, 11b can be easily inserted into the inner sides of the narrow gaps G1, G2 between the adjacent conductors 400 without decreasing the strength of the clamp arms 11a, 11 b. Therefore, according to the clamp sensor 2, the conductor 400a can be reliably clamped.

In the clamp sensor 2 and the clamp meter 1, the clamp arms 11a and 11b are formed as follows: the facing surfaces 101 on the outer peripheral side of the distal ends 21a, 21b of the clamp arms 11a, 11b are formed so as to be one plane orthogonal to the direction connecting the distal end 100a and the proximal end 100b of the annular body 100 in the formed state of the annular body 100, and the facing distance D1a of the facing surfaces 101 of the distal ends 21a, 21b is shorter than the facing distance D1b of the facing surfaces 101 of the clamp arms 11a, 11b at other positions than the distal ends 21a, 21 b. Therefore, according to the clamp sensor 2 and the clamp meter 1, the distal ends 21a and 21b of the clamp arms 11a and 11b can be more easily inserted into the narrow gaps G1 and G2. Further, since the relative distance D1a between the facing surfaces 101 at the respective distal end portions 21a, 21b is short, for example, even when an obstacle such as a wall is present behind the conductor 400 to be clamped and the gap between the conductor 400 and the obstacle is narrow, it is possible to avoid the obstacle from coming into contact with the respective clamping arms 11a, 11b and to reliably clamp the conductor 400 to be clamped.

In the clamp sensor 2 and the clamp meter 1, the clamp arms 11a and 11b are formed so that a length L103 along the straight line H1 between a position P, which is a position separated by 15mm from the center of the top 100a in a direction orthogonal to the straight line H1 and parallel to the opening surface F of the annular body 100, and the opposing surface 101 on the outer side of the annular body 100 is in a range of 9mm to 11 mm. In this case, when the clamp arms 11a, 11b are formed so that the length L103 is greater than 11mm, the shape of the clamp arms 11a, 11b on the sides of the tip ends 21a, 21b is too slender, and for example, when the clamp arms 11a, 11b are intended to clamp the conductor 400 arranged near the wall surface, the tip ends 21a, 21b of the clamp arms 11a, 11b may come into contact with the wall surface, and clamping may become difficult. Further, when the clamp arms 11a, 11b are formed so that the length L103 is greater than 11mm, the top 100a side of the annular body 100 is formed in an abnormally elongated shape, and the detection characteristics of the magnetic field (detected amount) may be deteriorated. On the other hand, when the clamp arms 11a, 11b are formed so that the length L103 is less than 9mm, the shape of the front end portions 21a, 21b sides of the clamp arms 11a, 11b is close to an arc shape, and for example, when one conductor 400 among the plurality of conductors 400 closely arranged is intended to be clamped by the clamp arms 11a, 11b, the front end portions 21a, 21b may be difficult to be inserted into a gap between the one conductor 400 and the adjacent other conductor 400, thereby making clamping difficult. In contrast, according to the clamp sensor 2, the clamp arms 11a and 11b are formed so that the length L103 is in the range of 9mm to 11mm, so that the detection characteristic of the magnetic field can be maintained well and the conductor 400 can be clamped more reliably.

In the clamp sensor 2 and the clamp meter 1, the clamp arms 11a and 11b are formed so that the relative distance D1 is the longest distance between any two points in the outer shape of the cut plane Sc1 at the tip end side portions 51a and 51b, and the relative distance D1 is the distance between the tip end portions 21a and 21b of the clamp arms 11a and 11b in a state where the tip end portions 21a and 21b are separated from each other the largest, and the relative distance D1 is in a range of 1/6 to 1/5 of the separation distance D102. In this case, when the clamp arms 11a, 11b are formed so that the ratio R is greater than 1/5, it is difficult to insert the tip ends 21a, 21b of the clamp arms 11a, 11b into the narrow gaps G1, G2 between the adjacent conductors 400 when clamping one of the conductors 400 arranged side by side at a narrow interval. On the other hand, when the clamp arms 11a, 11b are formed such that the ratio R is smaller than 1/6, the separation distance D102 in a state where the control lever 30a is pressed in to the greatest extent and the distal end portions 21a, 21b are separated from each other the greatest is excessively long, and when the plurality of conductors 400 are arranged side by side at a narrow interval, the plurality of conductors 400 may be clamped, and therefore, it is necessary to adjust the press-in amount of the control lever 30a, and the operability may be deteriorated. In contrast, according to the clamp sensor 2, the clamp arms 11a and 11b are formed so that the relative distance D1 is within a range of 1/6 to 1/5 of the separation distance D102, and the distal ends 21a and 21b can be easily inserted into the narrow gaps G1 and G2 between the adjacent conductors 400 in a state where the lever 30a is pressed in to the maximum extent, so that the operability can be sufficiently improved, and only one conductor among the plurality of conductors 400 can be clamped more reliably.

The configurations of the clamp sensor and the measuring device are not limited to the above-described configuration. As described above, for example, only the distal end portions 51a and 51b of the clamp arms 11a and 11b are formed such that the outline of the cut surface Sc1 is octagonal and the length L2 of each side E3 and E4 of the octagon is longer than the length L1 of each side E1 and E2, and the proximal end portions 52a and 52b of the clamp arms 11a and 11b are formed in a shape having a substantially rectangular cross section, but a configuration may be adopted in which both the distal end portions 51a and 51b and the proximal end portions 52a and 52b of the clamp arms 11a and 11b are formed in the above-described shape. With the above configuration, both the distal end portions 51a and 51b and the proximal end portions 52a and 52b of the clamp arms 11a and 11b can be easily inserted into the narrow gap.

Further, both the distal end portions 51a and 51b and the proximal end portions 52a and 52b of the clamp arms 11a and 11b may be formed such that the sides E3 and E4 are curved (arc-shaped).

In the above, the example was described in which the respective distal end side portions 51a and 51b of the clamp arms 11a and 11b were formed so that the respective sides E1 and E2 of the octagon, which is the outer shape of the cut plane Sc1, had the same length L1 and the respective sides E3 and E4 had the same length L2, but the respective distal end side portions 51a and 51b (or both of the respective distal end side portions 51a and 51b and the respective proximal end side portions 52a and 52 b) of the clamp arms 11a and 11b may be formed so that the respective sides E1 and E2 have different lengths and the respective sides E3 and E4 have different lengths.

In the above, the example in which the distal end portion side portions 51a and 551b of the clamp arms 11a and 11b are formed so that the length L2 of the entire sides E3 and E4 is longer than the length L1 of the sides E1 and E2 has been described, but the lengths of the sides E1, E2, E3 and E4 may be arbitrarily defined as long as the condition that at least one of the sides E3 and E4 is longer than the shortest length of the lengths of the sides E1 and E2 is satisfied.

In the above description, the example was described in which the respective clamp arms 11a and 11b were formed such that the relative distance D1a between the respective facing surfaces 101 at the tip portions 21a and 21b was shorter than the relative distance D1b between the respective facing surfaces 101 at the other portions of the clamp arms 11a and 11b than the tip portions 21a and 21b by cutting out a part of the outer peripheral side of the tip portion 100a of the annular body 100 (the part shown by the broken line in fig. 8), but a configuration may be adopted in which a part of the outer peripheral side of the tip portion 100a (the part shown by the broken line in fig. 8) is not cut out.

In the above, the example was described in which the clamp sensor 2 detects the magnetic field, which is the detected amount, and the processing unit 33 measures the current, which is the detected amount, but the detected amount and the detected amount are not limited to the magnetic field and the current, and include various physical amounts such as voltage, electric power, and resistance.

Further, a clamp meter 1A including the clamp sensor 2A and the body portion 3 shown in fig. 13 may be employed. In the following description, the same components as those of the clamp sensor 2 and the clamp meter 1 are denoted by the same reference numerals, and overlapping description thereof is omitted.

In the clamp sensor 2A, the tip end portions 51a and 51b and the base end portions 52A and 52b are defined as follows. First, as shown in fig. 13, a straight line H2 passing through a center of a drawing C2 of a top 100a of the annular body 100 and an inner periphery of the annular body 100 in a plan view (a drawing with oblique lines in the same drawing) is defined. Next, a length corresponding to 40% of a distance D101A (linear distance) from the top 100a (specifically, the outer facing surface 101 of the top 100a shown in fig. 8) to the centroid C2 is determined as a length L101A, and an arbitrary point within a range of the length L101A centered on the centroid C2 on the straight line H2 is defined (hereinafter, also referred to as a "defined point P101A"). In this case, in this example, a point separated from the centroid C2 toward the top 100a by a length corresponding to 14% of the distance D101 is defined as a predetermined point P101A. Next, a plane passing through the predetermined point P101A and orthogonal to the straight line H2 is defined as a boundary surface Sb2, the portions between the boundary surface Sb2 and the distal ends 21A, 21b at the clamp arms 11A, 11b are defined as distal end portion side portions 51A, 51b, and the portions between the boundary surface Sb1 and the proximal ends 22a, 222b are defined as proximal end portion side portions 52a, 52b.

In the clamp sensor 2A, as shown in fig. 7, the tip end portions 51a and 51b of the clamp arms 11a and 11b are formed in the same shape as those of the clamp sensor 2. In addition, in the clamp sensor 2A, as shown in fig. 6, the clamp arms 11a and 11b are formed such that the area Sa1 of the outer shape of the cut surface Sc1 at the tip end portion side portions 51a and 51b is smaller than the area Sa2 of the outer shape of the cut surface Sc2 at the base end portion side portions 52A and 52 b. Therefore, according to the clamp sensor 2A, the distal ends 21a, 21b of the clamp arms 11a, 1b can be easily inserted into the inner sides of the narrow gaps G1, G2 between the adjacent conductors 400 without reducing the strength of the clamp arms 11a, 11b, as in the clamp sensor 2. Therefore, according to the clamp sensor 2, the conductor 400 can be reliably clamped.

In addition, in the clamp sensor 2A, as shown in fig. 8, the clamp arms 11a and 11b are formed so that a length L103 along a straight line H1 between a position P, which is a position separated by 15mm from the center of the top 100a in a direction orthogonal to the straight line H1 and parallel to the opening surface F of the annular body 100, and the opposing surface 101 on the outer side of the annular body 100 is in a range of 9mm to 11 mm. Therefore, according to the clamp sensor 2A, the conductor 400 can be clamped more reliably while maintaining the detection characteristics of the magnetic field well, as in the clamp sensor 2.

In addition, in the clamp sensor 2A, as shown in fig. 9, the clamp arms 11a and 11b are also formed: the longest distance among the straight-line distances between any two points in the outer shape of the cut plane Sc1 at the tip end side portions 51a, 51b is set as the relative distance D1 (see also fig. 7), and the separation distance between the tip end portions 21a, 21b in the state where the tip end portions 21a, 21b of the respective clamp arms 11a, 11b are separated from each other the greatest is set as the separation distance D102, and at this time, the ratio R of the relative distance D1 to the separation distance D102 is in the range of 1/6 to 1/5. Therefore, according to the clamp sensor 2A, as in the clamp sensor 2, the tip portions 21a and 21b can be easily inserted into the narrow gaps G1 and G2 between the adjacent conductors 400 in a state where the lever 30a is pressed in to the maximum extent, and therefore, the operability can be sufficiently improved, and only one of the plurality of conductors 400 can be more reliably clamped.

In addition, the clamp sensor 202 shown in fig. 7 may also be employed. In the clamp sensor 202, as in the clamp sensor 2 described above, the tip end portions 51a and 51b of the clamp arms 11a and 11b have a pair of opposing surfaces 101, a pair of opposing surfaces 102, a pair of opposing surfaces 103, and a pair of opposing surfaces 104, and as shown in the same drawing, the tip end portions 51a and 51b of the clamp arms 11a and 11b are formed in an octagon shape (an example of an approximate octagon) as an outline of a cross section Sc1 orthogonal to the longitudinal direction of the clamp arms 11a and 11b (octagon shape formed by chamfering corners of a quadrangular prism shown by a broken line in the same drawing).

As shown in fig. 5, in the clamp sensor 202, as in the clamp sensor 2 described above, the portions between the boundary surface Sb1 and the distal ends 21a and 21b are defined as distal end portion side portions 51a and 51b, and the portions between the boundary surface Sb1 and the base ends 22a and 22b are defined as base end portion side portions 52a and 52b, and the boundary surface Sb1 passes through a predetermined point P101 defined on the straight line H1 within a range of the length L101 centered on the centroid C1 and is orthogonal to the straight line H1. As shown in fig. 13, the following structure may be adopted in the same manner as the clamp sensor 2A: the portions between the boundary surface Sb2 and the distal ends 21A, 21b are defined as distal end portion side portions 51A, 51b, and the portions between the boundary surface Sb2 and the base ends 22a, 22b are defined as base end portion side portions 52a, 52b, wherein the boundary surface Sb2 passes through a predetermined point P101A defined on the straight line H2 within a range of a length L101A centered on the centroid C2 and is orthogonal to the straight line H2.

In addition, in the clamp sensor 202, as shown in fig. 7, the distal end portion side portions 51a, 51b of the clamp arms 11a, 11b are formed as: of the sides of the octagon, which is the outline of the cut plane Sc1, the sides E1 corresponding to the opposing faces 101 and the sides E2 corresponding to the opposing faces 102 have the same length L1, and the sides E3 corresponding to the opposing faces 103 and the sides E4 corresponding to the opposing faces 104 have the same length L2. In addition, in the clamp sensor 202, the tip end side portions 51a and 51b are formed as follows: the relative distance D1 of each side E1 is the same as the relative distance D2 of each side E2, and the relative distance D3 of each side E3 (the relative distance between the line segment connecting the both ends of one side of each side E3 and the line segment connecting the both ends of the other side of each side E3) and the relative distance D4 of each side E4 (the relative distance between the line segment connecting the both ends of one side of each side E4 and the line segment connecting the both ends of the other side of each side E4) are the same. In the clamp sensor 202, the tip end portions 51a and 51b are formed such that the relative distances D3 and D4 are larger than (100/∈2)% of the relative distances D1 and D2 (any shorter distance of the relative distances D1 and D2) and are equal to or smaller than 110% of the relative distances D1 and D2 (any shorter distance of the relative distances D1 and D2) (99% is an example).

In this case, in the configuration in which the relative distances D3 and D4 are equal to or smaller than (100/∈2)% of the relative distances D1 and D2, the shape of the cut surface Sc1 is a thin shape (a long longitudinal or long transverse shape), and the core 41 is also thin, so that the magnetic characteristics may be degraded, and the detection accuracy of the detected amount may be lowered. On the other hand, in a configuration in which the relative distances D3 and D4 are made longer than 110% of the relative distances D1 and D2, it is difficult to sufficiently exhibit the effects described later that are caused by shortening the relative distances D3 and D4. Therefore, in order to maintain the detection accuracy of the detected amount at a high level and to sufficiently exhibit the effect of shortening the relative distances D3 and D4, the clamp sensor 202 has a structure in which the relative distances D3 and D4 are set to be within a range of greater than (100/∈2)% of the relative distances D1 and D3 and not more than 110% of the relative distances D1 and D3.

In the example shown in fig. 7, since each side E3 is a straight line, the relative distance between the line segment connecting the two ends of one side of each side E3 and the line segment connecting the two ends of the other side of each side E3 is the same as the relative distance D3 of each side E3, but a configuration in which each side E3 is a curve (arc shape) (the outline of the cut plane Sc1 is a configuration of approximately octagon) may be adopted in which the relative distance between the line segment connecting the two ends of one side of each side E3 and the line segment connecting the two ends of the other side of each side E3 is set to be the relative distance D3, and the relative distance D3 is within a range of more than (100/∈2)% of the relative distances D1, D2 and 110% or less of the relative distances D1, D2. Similarly, in the example shown in the same drawing, since each side E4 is a straight line, the relative distance between the line segment connecting the two ends of one side of each side E4 and the line segment connecting the two ends of the other side of each side E4 is the same as the relative distance D4 of each side E4, but a configuration may be adopted in which each side E4 is curved (arc-shaped) (the outline of the cut plane Sc1 is a configuration that approximates an octagon) in which the relative distance between the line segment connecting the two ends of one side of each side E4 and the line segment connecting the two ends of the other side of each side E4 is set to be the relative distance D4, and the relative distance D4 is within a range of more than (100/∈2)% of the relative distances D1, D2 and 110% or less of the relative distances D1, D2.

In addition, in the clamp sensor 202, as shown in fig. 7, the sensor housings 10a, 10b constituting the outer shells of the clamp arms 11a, 11b are formed as follows: the thickness T of each portion corresponding to each of the front end portion side portions 51a, 51b (hereinafter, also referred to as "front end portion side portions of the sensor housings 10a, 10 b") is uniform (or substantially uniform) in a state of being observed at the cut plane Sc 1.

In addition, in the clamp sensor 202, as shown in fig. 6, the clamp arms 11a and 11b are formed as follows: the base end portion side portions 52a, 52b of the clamp arms 11a, 11b are formed in a substantially rectangular shape in cross section, and the area Sa2 of the outline of the cut surface Sc2 of the base end portion side portions 52a, 52b is larger than the outline area Sa1 of the cut surface Sc1 of the tip end portion side portions 51a, 51b (the area Sa1 is smaller than the area Sa 2).

In addition, in the clamp sensor 202, as shown in fig. 8, the facing surface 101 constituting the outer peripheral surface of the annular body 100 at the distal ends 21a, 21b of the clamp arms 11a, 11b is formed to be a single plane orthogonal to the direction connecting the top 100a and the base end 100b of the annular body 100 in the formed state of the annular body 100. In the clamp sensor 202, each of the clamp arms 11a and 11b is formed as follows: the relative distance D1a between the facing surfaces 101 at the distal end portions 21a, 21b is shorter than the relative distance D1b between the facing surfaces 101 at the other portions of the clamp arms 11a, 11b than the distal end portions 21a, 21 b. Accordingly, in the clamp sensor 202, the length of the annular body 100 along the direction connecting the top 100a and the base end 100b is shortened in response to the shortening of the relative distance D1a between the facing surfaces 101 at the tip ends 21a, 21 b.

Here, as shown by the broken line in fig. 7, in the conventional structure (structure in which the corners of the quadrangular prism are not chamfered) in which the outline of the cut surface Sc1 is formed in a quadrangular shape at the tip end portion side portions 51a, 51b of the clamp arms 11a, 11b, the outline of the cut surface Sc1, that is, the distance between the opposite corners in the quadrangular shape (the diagonal distance D5 shown in the same drawing) is about 141% of the relative distance D1 of the sides E1 and the relative distance D2 of the sides E2 (in the case where the cut surface Sc1 is square). Therefore, in the conventional structure, as shown in fig. 11, when the gap G1 between the conductors 400a and 400b and the gap G2 between the conductors 400a and 400c are narrow, it is difficult to insert the distal ends 21a, 21b of the clamp arms 11a, 11b into the respective gaps G1, G2 when the clamp meter 1 is tilted.

In contrast, in the clamp sensor 202 and the clamp meter 1 including the clamp sensor 202, as described above, the distal end portions 51a and 51b of the clamp arms 11a and 11b are formed as follows: the relative distance D3 of each side E3 (or the relative distance D3 of the line segment connecting the both ends of one side of each side E3 and the line segment connecting the both ends of the other side of each side E3) and the relative distance D4 of each side E4 (or the relative distance D4 of the line segment connecting the both ends of one side of each side E4 and the line segment connecting the both ends of the other side of each side E4) among the sides constituting the outline of the cut plane Sc1 (in this example, octagon or nearly octagon) is in a range of more than (100/≡2)% of the relative distance D1 of each side E1 and the relative distance D2 of each side E2 and 110% or less of the relative distance D1 of each side E1 and the relative distance D2 of each side E2. Therefore, according to the clamp sensor 202 and the clamp meter 1, the relative distances D3 and D4 can be sufficiently shorter than the diagonal distance D5 of the cut surface Sc1 in the conventional structure, and therefore, the distal ends 21a and 21b of the clamp arms 11a and 11b can be easily inserted into the narrow gaps G1 and G2 in a state where the clamp meter 1 is inclined as compared with the conventional structure (see fig. 10 to 12). Therefore, according to the clamp sensor 202 and the clamp meter 1, even when another conductor 400 or an obstacle exists in the vicinity of the conductor 400 to be clamped, the conductor 400 to be clamped can be reliably clamped.

Further, according to the clamp sensor 202 and the clamp meter 1, since both the relative distances D3 and D4 (or both the relative distance D3 between the line segment connecting the two ends of one side of each side E3 and the line segment connecting the two ends of the other side of each side E3 and the relative distance D4 between the line segment connecting the two ends of one side of each side E4 and the line segment connecting the two ends of the other side of each side E4) are set to be within a range of greater than (100/≡2)% of the relative distances D2 and D3 and equal to or less than 110% of the relative distances D2 and D3, the respective distal end portion side portions 51a and 51b of each clamp arm 11a and 11b can be made sufficiently shorter than the diagonal distance D5 of the cut surface Sc1 in the conventional structure. Therefore, according to the clamp sensor 202 and the clamp meter 1, for example, even in a state where the clamp meter 1 is rotated in one of the right-hand rotation and the left-hand rotation around the longitudinal direction of the clamp meter 1 as an axis and tilted, the distal ends 21a, 21b of the clamp arms 11a, 11b can be easily inserted into the narrow gaps G1, G2.

In addition, in the clamp sensor 202 and the clamp meter 1, since the clamp arms 11a and 11b are formed so that the thicknesses T of the portions on the front end portions side of the sensor housings 10a and 10b constituting the housings of the clamp arms 11a and 11b are uniform (or substantially uniform) when viewed in the cross section Sc1, the stress concentration at the portions where the thicknesses T of the sensor housings 10a and 10b are thin can be avoided as compared with the structure where the thicknesses T of the portions on the front end portions side of the sensor housings 10a and 10b are non-uniform, and the strength of the sensor housings 10a and 10b can be improved, and therefore, breakage of the sensor housings 10a and 10b when the loads are applied to the sensor housings 10a and 10b can be reliably prevented.

In addition, in the clamp sensor 202 and the clamp meter 1, the clamp arms 11a and 11b are formed so that the area of the cut surface Sc2 of the base end portion side portions 52a and 52b is larger than the area of the cut surface Sc1 of the tip end portion side portions 51a and 51b, and therefore, the strength of the clamp arms 11a and 11b can be sufficiently improved as compared with a structure in which the clamp arms 11a and 11b are formed so that the area of the cut surface Sc1 of the tip end portion side portions 51a and 51b is the same as the area of the cut surface Sc2 of the base end portion side portions 52a and 52 b.

In the clamp sensor 202, as described above, the clamp arms 11a and 11b are formed such that the area Sa1 of the outer shape of the cut surface Sc1 of the distal end portion side portions 51a and 51b is smaller than the area Sa2 of the outer shape of the cut surface Sc2 of the proximal end portion side portions 52a and 52b (see fig. 6). Therefore, according to the clamp sensor 202, the distal ends 21a and 21b of the clamp arms 11a and 11b can be easily inserted into the inner sides of the narrow gaps G1 and G2 between the adjacent conductors 400 without reducing the strength of the clamp arms 11a and 11b, as in the clamp sensor 2. Therefore, according to the clamp sensor 202, the conductor 400 can be reliably clamped.

In addition, in the clamp sensor 202, as shown in fig. 8, the clamp arms 11a and 11b are formed so that a length L103 along a straight line H1 between a position P and the facing surface 101 on the outer side of the annular body 100 is in a range of 9mm to 11mm, the position P being separated from the center of the top 100a by 15mm in a direction orthogonal to the straight line H1 and parallel to the opening surface F of the annular body 100. Therefore, according to the clamp sensor 202, the conductor 400 can be clamped more reliably while maintaining the detection characteristics of the magnetic field well, as in the clamp sensor 2.

In addition, in the clamp sensor 202, as shown in fig. 9, the clamp arms 11a and 11b are also formed: the longest distance among the straight-line distances between any two points in the outer shape of the cut plane Sc1 at the tip end side portions 51a, 51b is set as the relative distance D1 (see also fig. 7), and the separation distance between the tip ends 21a, 21b in the state where the tip ends 21a, 21b of the respective clamp arms 11a, 11b are separated from each other the greatest is set as the separation distance D102, and at this time, the ratio R of the relative distance D1 to the separation distance D102 is in the range of 1/6 to 1/5. Therefore, according to the clamp sensor 202, as in the clamp sensor 2, the tip portions 21a and 21b can be easily inserted into the narrow gaps G1 and G2 between the adjacent conductors 400 in a state where the lever 30a is pushed in to the maximum extent, and therefore, the operability can be sufficiently improved, and only one of the plurality of conductors 400 can be more reliably clamped.

In addition, in the clamp sensor 202 and the clamp meter 1, the clamp arms 11a and 11b are formed as follows: the facing surfaces 101 on the outer peripheral side of the distal ends 21a, 21b of the clamp arms 11a, 11b are formed so as to be one plane orthogonal to the direction connecting the distal ends 100a and the base ends 100b of the annular body 100 in the formed state of the annular body 100, and the facing distance D1a of the facing surfaces 101 of the distal ends 21a, 21b is shorter than the facing distance D1b of the facing surfaces 101 of the clamp arms 11a, 11b at other positions than the distal ends 21a, 21b, whereby the distal ends 21a, 21b of the clamp arms 11a, 11b can be inserted into the narrow gaps G1, G2 more easily. Further, since the relative distance D1a between the facing surfaces 101 at the respective distal end portions 21a, 21b is short, for example, even when an obstacle such as a wall is present behind the conductor 400 to be clamped and the gap between the conductor 400 and the obstacle is narrow, it is possible to avoid the obstacle from coming into contact with the respective clamping arms 11a, 11b and to reliably clamp the conductor 400 to be clamped.

In addition, in the clamp sensor 202, the base end portions 52a and 52b of the clamp arms 11a and 11b may be formed in the same shape as the tip end portions 51a and 51 b. In addition, in the clamp sensor 202, the respective sides E1, E2 of the octagon, which is the outer shape of the cut surface Sc1, may be formed to have different lengths, and the respective sides E3, E4 may be formed to have different lengths. In addition, the clamp sensor 202 may have a configuration in which the relative distances D1 and D2 are different from each other and the relative distances D3 and D4 are different from each other. In addition, in the clamp sensor 202, the tip end side portions 51a and 51b may be formed so that only one of the relative distances D3 and D4 is within a range of more than (100/∈2)% of the relative distances D1 and D2 (any of the relative distances D1 and D2) and not more than 110% of the relative distances D1 and D2 (any of the relative distances D1 and D2). In addition, in the clamp sensor 202, both the distal end portions 51a and 51b and the proximal end portions 52a and 52b of the clamp arms 11a and 11b may be formed such that the sides E3 and E4 are curved (arc-shaped). In addition, in the clamp sensor 202, a part (a part shown by a broken line in fig. 8) of the outer peripheral side of the top 100a of the annular body 100 may be not cut off.

In addition, the clamp sensor 302 shown in fig. 7 may also be employed. In the clamp sensor 302, as in the clamp sensor 2 described above, the tip end portions 51a and 51b of the clamp arms 11a and 11b have a pair of opposing surfaces 101, a pair of opposing surfaces 102, a pair of opposing surfaces 103, and a pair of opposing surfaces 104, and as shown in the same drawing, the tip end portions 51a and 51b of the clamp arms 11a and 11b are formed in an octagonal (approximately octagonal) shape (for example, an octagon shape is formed by chamfering the corners of a quadrangular prism shown by a broken line in the same drawing) in a cross section Sc1 orthogonal to the longitudinal direction of the clamp arms 11a and 11 b.

As shown in fig. 5, in the clamp sensor 302, as in the clamp sensor 2 described above, the portions between the boundary surface Sb1 and the distal ends 21a and 21b are defined as distal end portion side portions 51a and 51b, and the portions between the boundary surface Sb1 and the base ends 22a and 22b are defined as base end portion side portions 52a and 52b, and the boundary surface Sb1 passes through a predetermined point P101 defined on the straight line H1 within a range of the length L101 centered on the centroid C1 and is orthogonal to the straight line H1. As shown in fig. 13, the following structure may be adopted in the same manner as the clamp sensor 2A: the portions between the boundary surface Sb2 and the distal ends 21A, 21b are defined as distal end portion side portions 51A, 51b, and the portions between the boundary surface Sb2 and the base ends 22a, 22b are defined as base end portion side portions 52a, 52b, wherein the boundary surface Sb2 passes through a predetermined point P101A defined on the straight line H2 within a range of a length L101A centered on the centroid C2 and is orthogonal to the straight line H2.

In addition, in the clamp sensor 302, as shown in fig. 7, the distal end portion side portions 51a, 51b of the clamp arms 11a, 11b are formed as: of the sides of the octagon, which is the outline of the cut plane Sc1, the sides E1 corresponding to the opposing faces 101 and the sides E2 corresponding to the opposing faces 102 have the same length L1, and the sides E3 corresponding to the opposing faces 103 and the sides E4 corresponding to the opposing faces 104 have the same length L2. In addition, in the clamp sensor 302, the tip end side portions 51a and 51b are formed as follows: the length L2 of each side E3, E4 is in the range of 57% or more and less than 1000% of the length L1 of each side E1, E2 (the shortest length among the lengths of each side E1, E2) (106% as an example).

In this case, in the configuration in which the length L2 is 1000% or more of the length L1, the shape of the cut surface Sc1 is formed in a thin shape (a long longitudinal or long transverse shape), and the core 41 is also thin in association with this, and therefore, the magnetic characteristics may be degraded, and the detection accuracy of the detected amount may be lowered. On the other hand, in a configuration in which the length L2 is smaller than 57% of the length L1, it is difficult to sufficiently exhibit the effect described below that the length L2 is lengthened to some extent by chamfering the corners of the quadrangular prism. Therefore, in order to maintain the detection accuracy of the detected amount to be high and to sufficiently exert the effect by making the length L2 long to a certain extent, the clamp sensor 2 has a structure in which the length L2 is set in a range of 57% to less than 1000% of the length L1.

In the example shown in fig. 7, since the sides E3 and E4 are straight lines, the length of the line segment connecting the both ends of the sides E3 and E4 is the same as the length of the sides E3 and E4, but a configuration in which the sides E3 and E4 are curved (arc-shaped) (a configuration in which the outline of the cut plane Sc1 is approximately octagonal) may be adopted, in which the length of the line segment connecting the both ends of the sides E3 and E4 is set to a length L2 and the length L2 is within a range of 57% or more and less than 1000% of the length L1 (the shortest length of the sides E1 and E2).

In addition, in the clamp sensor 302, as shown in fig. 7, the sensor housings 10a, 10b constituting the outer shells of the clamp arms 11a, 11b are formed as follows: the thickness T of each portion corresponding to each of the front end portion side portions 51a, 51b (hereinafter, also referred to as "front end portion side portions of the sensor housings 10a, 10 b") is uniform (or substantially uniform) in a state of being observed at the cut plane Sc 1.

In the clamp sensor 302, the clamp arms 11a and 11b may be formed such that the base end portions 52a and 52b of the clamp arms 11a and 11b are formed to have substantially rectangular cross sections and the cross section Sc2 of the base end portions 52a and 52b is larger than the cross section Sc1 of the tip end portions 51a and 51b (the area Sa1 is smaller than the area Sa 2).

In addition, in the clamp sensor 302, as shown in fig. 8, the facing surfaces 101 of the distal ends 21a, 21b of the clamp arms 11a, 11b that constitute the outer peripheral surface of the annular body 100 are formed to be a single plane orthogonal to the direction connecting the top 100a and the base end 100b of the annular body 100 in the formed state of the annular body 100. In the clamp sensor 302, each of the clamp arms 11a and 11b is formed as follows: the relative distance D1a between the facing surfaces 101 at the distal end portions 21a, 21b is shorter than the relative distance D1b between the facing surfaces 101 at the other portions of the clamp arms 11a, 11b than the distal end portions 21a, 21 b. Accordingly, in the clamp sensor 302, the length of the annular body 100 along the direction connecting the top 100a and the base end 100b is shortened in response to the shortening of the relative distance D1a between the facing surfaces 101 at the tip ends 21a, 21 b.

Here, as shown by the broken line in fig. 7, in the conventional structure in which the outline of the cut surface Sc1 at each tip end portion side portion 51a, 51b of the clamp arms 11a, 11b is formed in a quadrangle (a structure in which each corner portion of the quadrangular prism is not chamfered), the outline of the cut surface Sc1, that is, the distance between the opposite corners in the quadrangle (the diagonal distance D5 shown in the same drawing) is longer than the relative distance D1 of each side E1 and the relative distance D2 of each side E2. Therefore, in the conventional structure, as shown in fig. 11, when the gap G1 between the conductors 400a and 400b and the gap G2 between the conductors 400a and 400c are narrow, it is difficult to insert the distal ends 21a, 21b of the clamp arms 11a, 11b into the respective gaps G1, G2 when the clamp meter 1 is tilted.

In contrast, in the clamp sensor 302 and the clamp meter 1 including the clamp sensor 302, as described above, the distal end portions 51a and 51b of the clamp arms 11a and 11b are formed as follows: the length L2 of each of the sides E3, E4 (or the length L2 of a line connecting both ends of each of the sides E3, E4) constituting the outline (in this example, octagon or nearly octagon) of the cut surface Sc1 formed by chamfering each corner of the quadrangular prism is in the range of 57% to less than 1000% of the length L1 of each of the sides E1, E2. Therefore, according to the clamp sensor 302 and the clamp meter 1, the relative distances D3 and D4 can be made sufficiently shorter than the relative distance D5 of the cut surface Sc1 in the conventional structure by making the length L2 long to some extent, and therefore, the distal ends 21a and 21b of the clamp arms 11a and 11b can be easily inserted into the narrower gaps G1 and G2 in a state where the clamp meter 1 is inclined as compared with the conventional structure (see fig. 10 to 12). Therefore, according to the clamp sensor 302 and the clamp meter 1, even when another conductor 400 or an obstacle exists in the vicinity of the conductor 400 to be clamped, the conductor 400 to be clamped can be reliably clamped.

Further, according to the clamp sensor 302 and the clamp meter 1, the distal end portions 51a and 51b of the clamp arms 11a and 11b are formed such that the length L2 of the entire sides E3 and E4 (or the length L2 of all line segments connecting both ends of the sides E3 and E4) is in the range of 57% or more and less than 1000% of the length L1 of the sides E1 and E2, and therefore, both the relative distances D3 and D4 can be made sufficiently shorter than the relative distance D5 of the cut surface Sc1 of the conventional structure. Therefore, according to the clamp sensor 302 and the clamp meter 1, for example, even in a state where the clamp meter 1 is rotated in either one of the right-hand rotation and the left-hand rotation about the longitudinal direction of the clamp meter 1 and tilted, the distal ends 21a, 21b of the clamp arms 11a, 11b can be easily inserted into the narrow gaps G1, G2.

In addition, in the clamp sensor 302 and the clamp meter 1, since the clamp arms 11a and 11b are formed so that the thickness T of the portion on the front end side of the sensor housings 10a and 10b constituting the housing of the clamp arms 11a and 11b is uniform (or substantially uniform) when viewed in the section Sc1, the stress concentration in the portion where the thickness T of the sensor housings 10a and 10b is thin can be avoided as compared with the structure where the thickness T of the portion on the front end side of the sensor housings 10a and 10b is non-uniform, and the strength of the sensor housings 10a and 10b can be improved, and therefore, breakage of the sensor housings 10a and 10b when the load acts on the sensor housings 10a and 10b can be reliably prevented.

In addition, in the clamp sensor 302 and the clamp meter 1, the clamp arms 11a and 11b are formed so that the area of the cut surface Sc2 of the base end portion side portions 52a and 52b is larger than the area of the cut surface Sc1 of the tip end portion side portions 51a and 51b, and therefore, the strength of the clamp arms 11a and 11b can be sufficiently improved as compared with a structure in which the clamp arms 11a and 11b are formed so that the area of the cut surface Sc1 of the tip end portion side portions 51a and 51b is the same as the area of the cut surface Sc2 of the base end portion side portions 52a and 52 b.

In the clamp sensor 302, as described above, the clamp arms 11a and 11b are formed such that the area Sa1 of the outer shape of the cut surface Sc1 at the distal end portion side portions 51a and 51b is smaller than the area Sa2 of the outer shape of the cut surface Sc2 at the proximal end portion side portions 52a and 52b (see fig. 6). Therefore, according to the clamp sensor 302, the distal ends 21a and 21b of the clamp arms 11a and 11b can be easily inserted into the inner sides of the narrow gaps G1 and G2 between the adjacent conductors 400 without reducing the strength of the clamp arms 11a and 11b, as in the clamp sensor 2. Therefore, according to the clamp sensor 302, the conductor 400 can be reliably clamped.

In addition, in the clamp sensor 302, as shown in fig. 8, the clamp arms 11a and 11b are formed so that a length L103 along a straight line H1 between a position P and the facing surface 101 on the outer side of the annular body 100 is in a range of 9mm to 11mm, the position P being separated from the center of the top 100a by 15mm in a direction orthogonal to the straight line H1 and parallel to the opening surface F of the annular body 100. Therefore, according to the clamp sensor 302, the conductor 400 can be clamped more reliably while maintaining the detection characteristics of the magnetic field well, as in the clamp sensor 2.

In addition, in the clamp sensor 302, as shown in fig. 9, the clamp arms 11a and 11b are also formed: the longest distance among the straight-line distances between any two points in the outer shape of the cut plane Sc1 at the tip end side portions 51a, 51b is set as the relative distance D1 (see also fig. 7), and the separation distance between the tip ends 21a, 21b in the state where the tip ends 21a, 21b of the respective clamp arms 11a, 11b are separated from each other the greatest is set as the separation distance D102, and at this time, the ratio R of the relative distance D1 to the separation distance D102 is in the range of 1/6 to 1/5. Therefore, according to the clamp sensor 302, as in the clamp sensor 2, the tip portions 21a and 21b can be easily inserted into the narrow gaps G1 and G2 between the adjacent conductors 400 in a state where the lever 30a is pushed in to the maximum extent, and therefore, the operability can be sufficiently improved, and only one of the plurality of conductors 400 can be more reliably clamped.

In addition, in the clamp sensor 302 and the clamp meter 1, the clamp arms 11a and 11b are formed as follows: the facing surfaces 101 on the outer peripheral side of the distal ends 21a, 21b of the clamp arms 11a, 11b are formed so as to be one plane orthogonal to the direction connecting the distal ends 100a and the base ends 100b of the annular body 100 in the formed state of the annular body 100, and the facing distance D1a of the facing surfaces 101 of the distal ends 21a, 21b is shorter than the facing distance D1b of the facing surfaces 101 of the clamp arms 11a, 11b at other positions than the distal ends 21a, 21b, whereby the distal ends 21a, 21b of the clamp arms 11a, 11b can be inserted into the narrow gaps G1, G2 more easily. Further, since the relative distance D1a between the facing surfaces 101 at the respective distal end portions 21a, 21b is short, for example, even when an obstacle such as a wall is present behind the conductor 400 to be clamped and the gap between the conductor 400 and the obstacle is narrow, it is possible to avoid the obstacle from coming into contact with the respective clamping arms 11a, 11b and to reliably clamp the conductor 400 to be clamped.

In addition, in the clamp sensor 302, the base end portions 52a and 52b of the clamp arms 11a and 11b may be formed in the same shape as the tip end portions 51a and 51 b. In addition, in the clamp sensor 302, the respective sides E1, E2 of the octagon, which is the outer shape of the cut surface Sc1, may be formed to have different lengths, and the respective sides E3, E4 may be formed to have different lengths. In addition, in the clamp sensor 302, the length of each side E1, E2, E3, E4 can be arbitrarily defined as long as the condition that the length of at least one of the sides E3, E4 is within a range of 57% or more and less than 100% of the shortest length of the sides E1, E2 is satisfied. In addition, in the clamp sensor 302, both the distal end portion side portions 51a and 51b and the proximal end portion side portions 52a and 52b of the clamp arms 11a and 11b may be formed such that the sides E3 and E4 are formed in a curved shape (arc shape). In addition, in the clamp sensor 302, a part (a part shown by a broken line in fig. 8) of the outer peripheral side of the top 100a of the annular body 100 may be not cut off.

Further, although the example in which the distal end portion side portions 51a, 51b are formed so that the outer shape of the cut surface Sc1 of the distal end portion side portions 51a, 51b of the clamp arms 11a, 11b is approximately octagonal has been described above, the distal end portion side portions 51a, 51b may be formed so that the outer shape of the cut surface Sc1 is formed in a polygonal shape other than approximately octagonal (for example, approximately dodecagonal or approximately dodecagonal). As an example, the clamp sensor 402 shown in fig. 14 can be employed.

In the clamp sensor 402, the tip end portions 51a and 51b of the clamp arms 11a and 11b have a pair of opposing surfaces 101 corresponding to the first opposing surfaces, a pair of opposing surfaces 102 corresponding to the second opposing surfaces, a pair of opposing surfaces 103a inclined with respect to the opposing surfaces 101 and 102, a pair of opposing surfaces 103b, a pair of opposing surfaces 104a, and a pair of opposing surfaces 104b (each corresponding to a third opposing surface, and four pairs of third opposing surfaces are taken as an example of a plurality of pairs), and the tip end portions 51a and 51b of the clamp arms 11a and 11b are formed in a shape of approximately twelve sides in the outer shape of a cross section Sc1 orthogonal to the longitudinal direction of the clamp arms 11a and 11 b. Since the cross-sectional shapes of the tip-end- side portions 51a and 51b are the same, only the cross-sectional shape of the tip-end-side portion 51a is shown in the same drawing, and the cross-sectional shape of the tip-end-side portion 51b is not shown.

In addition, in the clamp sensor 402, as shown in fig. 14, the distal end portion side portions 51a, 51b of the clamp arms 11a, 11b are formed as: of the sides of the dodecagon, which is the outline of the cut plane Sc1, each side E1 corresponding to each opposing surface 101 and each side E2 corresponding to each opposing surface 102 have the same length L1, and the lengths of each side E3a, E3b corresponding to each opposing surface 103a, 103b (the lengths of the line segments connecting the respective both ends of each side E3a, E3 b) and the lengths of each side E4a, E4b corresponding to each opposing surface 104a, 104b (the lengths of the line segments connecting the respective both ends of each side E4a, E4 b) are the same length L2. In addition, in the clamp sensor 402, the tip end side portions 51a and 51b are formed so that the length L2 is longer than the length L1 (the shortest length among the lengths of the sides E1 and E2).

In addition, in the clamp sensor 402, as shown in fig. 14, the sensor housings 10a, 10b constituting the housings of the clamp arms 11a, 11b are formed as follows: the thickness T of each portion corresponding to each of the front end portion side portions 51a, 51b (hereinafter, also referred to as "front end portion side portions of the sensor housings 10a, 10 b") is uniform (or substantially uniform) in a state of being observed at the cut plane Sc 1. Therefore, in the clamp sensor 402, stress concentration in the portion where the thickness T of the sensor housing 10a or 10b is small can be avoided and the strength of the sensor housing 10a or 10b can be improved, as compared with a structure where the thickness T of the portion on the tip end side of the sensor housing 10a or 10b is not uniform, and therefore breakage of the sensor housing 10a or 10b when a load is applied to the sensor housing 10a or 10b can be reliably prevented.

In addition, in the clamp sensor 402, as shown in fig. 14, the tip end side portions 51a and 51b may be formed: the contour of the cut plane Sc1, that is, the relative distance D1 of each side E1 and the relative distance D2 of each side E2 of the dodecagon are the same distance, the relative distances D3a, D3b of each side E3a, E3b (the relative distance between the line segment connecting the both ends of one side of each side E3a, E3b and the line segment connecting the both ends of the other side of each side E3a, E3 b) and the relative distances D4a, D4b of each side E4a, E4b (the relative distance between the line segment connecting the both ends of one side of each side E4a, E4b and the line segment connecting the both ends of the other side of each side E4a, E4 b) are the same distance, and the relative distances D3a, D3b, D4a, D4b are larger than (100/by2)% of the relative distances D1, D2 (the arbitrary short distance of the relative distances D1, D2) and the relative distances D1, D2 (the arbitrary short distance of the relative distances D1, D2) are also possible to achieve the above-mentioned effects as one example (99%).

In addition, in the clamp sensor 402, as shown in fig. 14, the tip end side portions 51a and 51b may be formed so that the length L2 of each side E3a, E3b, E4a, E4b of the dodecagon, which is the outer shape of the cut surface Sc1, is within a range of 57% or more and less than 1000% of the length L1 of each side E1, E2 (the shortest length among the lengths of each side E1, E2) (106% as an example), and in this case, the above-described effects can be achieved.

Further, when three or more pairs of third opposing faces inclined with respect to the first opposing face and the second opposing face are provided and the pair of pairs (the number of sets) of the third opposing faces is set to n, various polygonal structures in which the outer shape of the cut plane Sc1 is formed in an approximate (4+2n) polygon (n is a natural number of 2 or more) can be applied, and in this case, the above-described effects can be achieved.

The tip end side portions 51a and 51b may be formed in a shape in which a part of the outer shape of the cut surface Sc1 is formed by a curve. As an example, the clamp sensor 502 shown in fig. 15 can be used. Since the cross-sectional shapes of the tip-end- side portions 51a and 51b are the same, only the cross-sectional shape of the tip-end-side portion 51a is shown in the same drawing, and the cross-sectional shape of the tip-end-side portion 51b is not shown.

In this clamp sensor 502, as shown in fig. 15, the distal end portions 51a and 51b of the clamp arms 11a and 11b have a pair of opposing surfaces 101 (corresponding to first opposing surfaces) constituting the outer peripheral surface and the inner peripheral surface of the annular body 100, and a pair of opposing surfaces 102 (corresponding to second opposing surfaces) constituting both side surfaces of the annular body 100, and the distal end portions 51a and 51b of the clamp arms 11a and 11b are formed in such a shape that the outer shape of a cross section Sc1 orthogonal to the longitudinal direction of the clamp arms 11a and 11b is cut away from both ends in the longitudinal direction of an ellipse in a direction perpendicular to the opening surface F of the annular body 100 (left-right direction in the same drawing). In the clamp sensor 502, each side E1 corresponding to each facing surface 101 among the sides constituting the outer shape of the cut surface Sc1 is formed as a straight line, and each side E2 corresponding to each facing surface 102 is formed as a curved line (a shape in which each corner of a quadrangular prism shown by a broken line in the same drawing is chamfered) curved toward the outside. In addition, in the clamp sensor 502, the distal end portions 51a and 51b of the clamp arms 11a and 11b are formed such that the longest relative distance D6 of the sides E2 along the direction perpendicular to the opening surface F of the annular body 100 is equal to or less than the relative distance D1 of the sides E1. In the clamp sensor 502, the distal end portions 51a and 51b of the clamp arms 11a and 11b are formed in the above-described manner, so that the longest relative distances D7 and D8 of the sides E2 are equal to or less than the relative distance D1 of the sides E1, as shown in the same drawing. In the same drawing, an example is illustrated in which the relative distance D1 is equal to the relative distances D7 and D8.

In addition, in the clamp sensor 502, as shown in fig. 15, the sensor housings 10a, 10b constituting the outer shells of the clamp arms 11a, 11b are formed as follows: the thickness T of each portion corresponding to each of the front end portion side portions 51a, 51b (hereinafter, also referred to as "front end portion side portions of the sensor housings 10a, 10 b") is uniform (or substantially uniform) in a state of being observed at the cut plane Sc 1.

According to the clamp sensor 502 and the clamp meter 1 including the clamp sensor 502, the front end portions 51a and 51b of the clamp arms 11a and 11b are formed so that each side E1 of each side constituting the outer shape of the cut surface Sc1 is a straight line and each side E2 is a curved line curved outward, and the longest relative distances D7 and D8 of each side E2 can be set equal to or smaller than the relative distance D1 of each side E1, so that the front end portions 21a and 21b of the clamp arms 11a and 11b can be easily inserted into the gaps G1 and G2 in a state where the clamp meter 1 is inclined, as compared with a conventional structure (a structure where the corners of a quadrangular prism are not chamfered) in which the outer shape of the cut surface Sc1 of each front end portion 51a and 51b of the clamp arms 11a and 11b is a square and the diagonal distance D5 of the cut surface Sc1 is longer than the relative distances D1 of each side E1 and the longest relative distances D7 and D8 of each side E2. Therefore, according to the clamp sensor 502 and the clamp meter 1, even when another conductor 400 or an obstacle exists in the vicinity of the conductor 400 to be clamped, the conductor 400 to be clamped can be reliably clamped.

In addition, in the clamp sensor 502 and the clamp meter 1 including the clamp sensor 502, the distal end portion side portions 51a and 51b of the clamp arms 11a and 11b are formed so that the longest relative distance D6 of the sides E2 along the direction perpendicular to the opening surface F of the ring body 100 is equal to or less than the relative distance D1 of the sides E1. Therefore, according to the clamp sensor 502 and the clamp meter 1, the clamp meter 1 is inclined so that the inclination angle of the opening surface F of the annular body 100 with respect to the extending direction of the conductor 400 becomes smaller, and the distal ends 21a, 21b of the clamp arms 11a, 11b can be more easily inserted into the narrow gaps G1, G2.

Further, according to the clamp sensor 502 and the clamp meter 1 including the clamp sensor 502, since the clamp arms 11a and 11b are formed such that the thickness T of the portion on the front end side of the sensor housings 10a and 10b constituting the housing of the clamp arms 11a and 11b is uniform (or substantially uniform) when viewed in the cross section Sc1, the stress concentration of the portion where the thickness T of the sensor housings 10a and 10b is thin can be avoided as compared with the structure where the thickness T of the portion on the front end side of the sensor housings 10a and 10b is not uniform, and the strength of the sensor housings 10a and 10b can be improved, and therefore breakage of the sensor housings 10a and 10b when a load is applied to the sensor housings 10a and 10b can be reliably prevented.

As another example of the structure in which the tip end portion side portions 51a, 51b are formed in a shape in which a part of the outer shape of the cut surface Sc1 is formed by a curve, a clamp sensor 602 shown in fig. 16 can be employed. Since the cross-sectional shapes of the tip-end- side portions 51a and 51b are the same, only the cross-sectional shape of the tip-end-side portion 51a is shown in the same drawing, and the cross-sectional shape of the tip-end-side portion 51b is not shown.

In this clamp sensor 602, as shown in fig. 16, the distal end side portions 51a and 51b of the clamp arms 11a and 11b have a pair of opposing surfaces 101 (corresponding to first opposing surfaces) constituting the outer peripheral surface and the inner peripheral surface of the annular body 100, a pair of opposing surfaces 102 (corresponding to second opposing surfaces) constituting both side surfaces of the annular body 100, and two pairs of opposing surfaces 105 (corresponding to fourth opposing surfaces) located between the opposing surfaces 101 and 102, and the outer shape of a cross section Sc1 orthogonal to the longitudinal direction of the clamp arms 11a and 11b is formed in such a shape that the corners of a quadrangle are rounded (rounded). In addition, in the clamp sensor 602, each side E1 corresponding to each opposing surface 101 and each side E2 corresponding to each opposing surface 102 among the sides constituting the outer shape of the cut surface Sc1 are formed as straight lines, and each side E5 corresponding to each opposing surface 105 is formed as a curved line curved outward (formed as a shape in which each corner of a quadrangular prism shown by a broken line in the same drawing is chamfered into a curved shape). In addition, in the clamp sensor 602, the distal end portions 51a and 51b of the clamp arms 11a and 11b are formed so that the relative distance D9 of the sides E2 is equal to or smaller than the relative distance D1 of the sides E1. In the clamp sensor 602, the distal end portions 51a and 51b of the clamp arms 11a and 11b are formed in the above-described manner, so that the longest relative distances D10 and D11 of the opposing sides E5 are equal to or less than the relative distance D1 of the sides E1, as shown in the same drawing. In the same drawing, an example is illustrated in which the relative distance D1 is equal to the relative distances D10 and D11.

In addition, in the clamp sensor 602, as shown in fig. 16, the sensor housings 10a, 10b constituting the outer shells of the clamp arms 11a, 11b are formed as follows: the thickness T of each portion corresponding to each of the front end portion side portions 51a, 51b (hereinafter, also referred to as "front end portion side portions of the sensor housings 10a, 10 b") is uniform (or substantially uniform) in a state of being observed at the cut plane Sc 1.

According to the clamp sensor 602 and the clamp meter 1 including the clamp sensor 602, the distal end portions 51a and 51b of the clamp arms 11a and 11b are formed so that the respective sides E1 and E2 of the outer shape of the clamp arm 11b are formed as straight lines and the respective sides E5 are formed as curved lines curved outward, so that the longest relative distances D10 and D11 of the respective sides E5 can be set to be equal to or smaller than the relative distance D1 of the respective sides E1, and therefore, the distal ends 21a and 21b of the clamp arms 11a and 11b can be easily inserted into the gaps G1 and G2 in a state where the clamp meter 1 is tilted, as compared with a conventional structure (a structure where the corners of a quadrangular prism are not chamfered) in which the outer shape of the cross section Sc1 of the respective distal end portions 51a and 51b of the clamp arms 11a and 11b is formed as a quadrangle and the diagonal distance D5 of the cross section Sc1 is longer than the relative distances D1 of the respective sides E1 and the relative distances D9 of the respective sides E2. Therefore, according to the clamp sensor 602 and the clamp meter 1, even when another conductor 400 or an obstacle exists in the vicinity of the conductor 400 to be clamped, the conductor 400 to be clamped can be reliably clamped.

In addition, in the clamp sensor 602 and the clamp meter 1 including the clamp sensor 602, the distal end portions 51a and 51b of the clamp arms 11a and 11b are formed so that the relative distance D9 of the sides E2 is equal to or smaller than the relative distance D1 of the sides E1. Therefore, according to the clamp sensor 602 and the clamp meter 1, the clamp meter 1 is inclined so that the inclination angle of the opening surface F of the annular body 100 with respect to the extending direction of the conductor 400 becomes smaller, and the distal ends 21a, 21b of the clamp arms 11a, 11b can be more easily inserted into the narrow gaps G1, G2.

Further, according to the clamp sensor 602 and the clamp meter 1 including the clamp sensor 602, since the clamp arms 11a and 11b are formed such that the thickness T of the portion on the front end side of the sensor housings 10a and 10b constituting the housing of the clamp arms 11a and 11b is uniform (or substantially uniform) when viewed in the cross section Sc1, the stress concentration of the portion where the thickness T of the sensor housings 10a and 10b is thin can be avoided as compared with the structure where the thickness T of the portion on the front end side of the sensor housings 10a and 10b is not uniform, and the strength of the sensor housings 10a and 10b can be improved, and therefore breakage of the sensor housings 10a and 10b when a load is applied to the sensor housings 10a and 10b can be reliably prevented.

Further, although the example in which the clamp arm 11b (one of the clamp arms 11a and 11 b) is configured to be rotatable has been described above, the clamp arm 11a may be configured to be rotatable, or both the clamp arms 11a and 11b may be configured to be rotatable.

Industrial applicability

According to the present invention, since the tip ends of the clamp arms can be easily inserted into the narrow gap in a state where the measuring device is tilted, for example, even when another conductor or an obstacle is present in the vicinity of the conductor to be clamped, the conductor to be clamped can be reliably clamped. Therefore, the present invention can be widely applied to a clamp sensor for detecting a detected amount of a clamp object and a measuring device for measuring the detected amount of the clamp object.

Symbol description

1. A clamp meter;

2. 2A, 202, 302, 402, 502, 602 jaw sensors;

11a, 11b clamping arms;

front end portions 21a, 21 b;

22a, 22b base end portions;

23. a rotating shaft;

33. a processing section;

41. a core;

front end portions 51a, 51 b;

52a, 52b base end portions;

100. an annular body;

100a top;

400. 400a conductors;

101-105, 103a, 103b, 104a, 104b opposite faces;

C1, C2 chart cores;

D1-D11 relative distance;

d102 A separation distance;

edges E1 to E5, E3a, E3b, E4a and E4 b;

h1, H2 straight lines;

l1, L2 length;

l101, L101A, L, L103 length;

a Mc magnetic circuit;

a P position;

p101 and P101A set points;

area of Sa1, sa 2;

sb1, sb2 boundary surfaces;

sc1 and Sc 2;

t thickness.

Claims (21)

1. A clamp sensor including a pair of clamp arms each formed to be approximately arc-shaped in a plan view, at least one of the pair of clamp arms being configured to be rotatable to open and close each of front end portions of the pair of clamp arms to each other, so that the pair of clamp arms form a ring-shaped body in a state where the front end portions are closed to each other, the clamp sensor being configured to be capable of detecting a detected amount of a clamping object in a state where the clamping object is clamped by each of the clamp arms,

it is characterized in that the method comprises the steps of,

each portion of the tip portion side of each of the clamp arms has a pair of first opposing faces that constitute an outer peripheral face and an inner peripheral face of the annular body, a pair of second opposing faces that constitute both side faces of the annular body, and a plurality of third opposing faces that are inclined with respect to each of the first opposing faces and each of the second opposing faces, each portion of the tip portion side of each of the clamp arms being formed as: the length of a line segment connecting both ends of at least one of the sides corresponding to the third opposing faces is longer than the shortest length of the sides corresponding to the first opposing faces and the second opposing faces among the sides constituting the outer shape of the cross section orthogonal to the longitudinal direction of the clamping arms.

2. The clamp sensor according to claim 1, wherein,

each position on the front end portion side of each of the clamp arms is formed as: all the line segments connecting the respective ends of the respective sides corresponding to the respective third opposing faces are longer than the shortest length among the lengths of the respective sides corresponding to the respective first opposing faces and the respective second opposing faces.

3. A clamp sensor including a pair of clamp arms each formed to be approximately arc-shaped in a plan view, at least one of the pair of clamp arms being configured to be rotatable to open and close each of front end portions of the pair of clamp arms to each other, so that the pair of clamp arms form a ring-shaped body in a state where the front end portions are closed to each other, the clamp sensor being configured to be capable of detecting a detected amount of a clamping object in a state where the clamping object is clamped by each of the clamp arms,

it is characterized in that the method comprises the steps of,

each portion of the tip portion side of each of the clamp arms has a pair of first opposing faces that constitute an outer peripheral face and an inner peripheral face of the annular body, a pair of second opposing faces that constitute both side faces of the annular body, and a plurality of third opposing faces that are inclined with respect to each of the first opposing faces and each of the second opposing faces, each portion of the tip portion side of each of the clamp arms being formed as: among the sides constituting the outer shape of the cross section orthogonal to the longitudinal direction of each of the clamp arms, the relative distance between a line segment connecting both end portions of one of the sides corresponding to each of the third opposite sides and facing each other and a line segment connecting both end portions of the other of the sides is within the following range: and (100/. V.2)% greater than any shorter distance of the respective sides corresponding to the respective first opposite faces and the respective sides corresponding to the respective second opposite faces, and 110% or less of the any shorter distance.

4. The clamp sensor of claim 3,

each position on the front end portion side of each of the clamp arms is formed as: the relative distances of all combinations of the sides that are opposite to each other lie within the following ranges: is greater than (100/. V.2)% of any shorter distance of the relative distances of the sides corresponding to the first opposite faces and the relative distances of the sides corresponding to the second opposite faces, and is 110% or less of the any shorter distance.

5. A clamp sensor including a pair of clamp arms each formed to be approximately arc-shaped in a plan view, at least one of the pair of clamp arms being configured to be rotatable to open and close each of front end portions of the pair of clamp arms to each other, so that the pair of clamp arms form a ring-shaped body in a state where the front end portions are closed to each other, the clamp sensor being configured to be capable of detecting a detected amount of a clamping object in a state where the clamping object is clamped by each of the clamp arms,

it is characterized in that the method comprises the steps of,

each portion of the tip portion side of each of the clamp arms has a pair of first opposing faces that constitute an outer peripheral face and an inner peripheral face of the annular body, a pair of second opposing faces that constitute both side faces of the annular body, and a plurality of third opposing faces that are inclined with respect to each of the first opposing faces and each of the second opposing faces, each portion of the tip portion side of each of the clamp arms being formed as: the length of a line segment connecting both ends of at least one of the sides corresponding to each of the third facing surfaces among the sides constituting the outer shape of the cross section orthogonal to the longitudinal direction of each of the clamp arms is within the following range: 57% or more of the shortest length among the lengths of the sides respectively corresponding to the first opposing faces and the second opposing faces, and less than 1000% of the shortest length.

6. The clamp sensor of claim 5,

each position on the front end portion side of each of the clamp arms is formed as: the lengths of all the line segments connected with the respective two ends of the sides respectively corresponding to the third opposite sides are within the following ranges: 57% or more of the shortest length among the lengths of the sides respectively corresponding to the first opposing faces and the second opposing faces, and less than 1000% of the shortest length.

7. A clamp sensor including a pair of clamp arms each formed to be approximately arc-shaped in a plan view, at least one of the pair of clamp arms being configured to be rotatable to open and close each of front end portions of the pair of clamp arms to each other, so that the pair of clamp arms form a ring-shaped body in a state where the front end portions are closed to each other, the clamp sensor being configured to be capable of detecting a detected amount of a clamping object in a state where the clamping object is clamped by each of the clamp arms,

it is characterized in that the method comprises the steps of,

each portion of each of the clamp arms on the tip end side has a pair of first opposing faces that constitute an outer peripheral face and an inner peripheral face of the annular body, and a pair of second opposing faces that constitute both side faces of the annular body, each portion of each of the clamp arms on the tip end side being formed as: of the sides constituting the outer shape of the cross section orthogonal to the longitudinal direction of each of the clamp arms, the sides corresponding to each of the first opposing faces are formed as straight lines, and the sides corresponding to each of the second opposing faces are formed as curved lines curving outward.

8. The clamp sensor of claim 7,

each position on the front end portion side of each of the clamp arms is formed as: the longest relative length of each side corresponding to each second opposing face along a direction perpendicular to the opening face of the annular body is equal to or less than the relative distance of each side corresponding to each first opposing face.

9. The clamp sensor according to claim 1, wherein,

each of the clamping arms includes a sensor housing forming a housing for each of the clamping arms,

each of the sensor housings is formed as: the thickness of each portion corresponding to the front end portion side of each of the clamp arms is uniform or substantially uniform in a state of being observed at the cut surface.

10. The clamp sensor of claim 3,

each of the clamping arms includes a sensor housing forming a housing for each of the clamping arms,

each of the sensor housings is formed as: the thickness of each portion corresponding to the front end portion side of each of the clamp arms is uniform or substantially uniform in a state of being observed at the cut surface.

11. The clamp sensor of claim 5,

Each of the clamping arms includes a sensor housing forming a housing for each of the clamping arms,

each of the sensor housings is formed as: the thickness of each portion corresponding to the front end portion side of each of the clamp arms is uniform or substantially uniform in a state of being observed at the cut surface.

12. The clamp sensor of claim 7,

each of the clamping arms includes a sensor housing forming a housing for each of the clamping arms,

each of the sensor housings is formed as: the thickness of each portion corresponding to the front end portion side of each of the clamp arms is uniform or substantially uniform in a state of being observed at the cut surface.

13. The clamp sensor according to claim 1, wherein,

each of the clamping arms is formed as: the cross-sectional area of each portion on the base end side of each of the clamp arms is larger than the cross-sectional area of each portion on the tip end side.

14. The clamp sensor of claim 3,

each of the clamping arms is formed as: the cross-sectional area of each portion on the base end side of each of the clamp arms is larger than the cross-sectional area of each portion on the tip end side.

15. The clamp sensor of claim 5,

each of the clamping arms is formed as: the cross-sectional area of each portion on the base end side of each of the clamp arms is larger than the cross-sectional area of each portion on the tip end side.

16. The clamp sensor of claim 7,

each of the clamping arms is formed as: the cross-sectional area of each portion on the base end side of each of the clamp arms is larger than the cross-sectional area of each portion on the tip end side.

17. The clamp sensor according to claim 1, wherein,

each of the clamping arms is formed as: the first opposing surfaces of the outer peripheral surfaces of the tip portions of the clamp arms are formed as a plane orthogonal to a direction connecting the tip portion and the base portion of the annular body in a state in which the annular body is formed, and a relative distance between the first opposing surfaces of the tip portions of the clamp arms is shorter than a relative distance between the first opposing surfaces of the clamp arms at other portions than the tip portions.

18. The clamp sensor of claim 3,

Each of the clamping arms is formed as: the first opposing surfaces of the outer peripheral surfaces of the tip portions of the clamp arms are formed as a plane orthogonal to a direction connecting the tip portion and the base portion of the annular body in a state in which the annular body is formed, and a relative distance between the first opposing surfaces of the tip portions of the clamp arms is shorter than a relative distance between the first opposing surfaces of the clamp arms at other portions than the tip portions.

19. The clamp sensor of claim 5,

each of the clamping arms is formed as: the first opposing surfaces of the outer peripheral surfaces of the tip portions of the clamp arms are formed as a plane orthogonal to a direction connecting the tip portion and the base portion of the annular body in a state in which the annular body is formed, and a relative distance between the first opposing surfaces of the tip portions of the clamp arms is shorter than a relative distance between the first opposing surfaces of the clamp arms at other portions than the tip portions.

20. The clamp sensor of claim 7,

each of the clamping arms is formed as: the first opposing surfaces of the outer peripheral surfaces of the tip portions of the clamp arms are formed as a plane orthogonal to a direction connecting the tip portion and the base portion of the annular body in a state in which the annular body is formed, and a relative distance between the first opposing surfaces of the tip portions of the clamp arms is shorter than a relative distance between the first opposing surfaces of the clamp arms at other portions than the tip portions.

21. An assay device, comprising:

the clamp sensor of any one of claims 1 to 20; and

and a measuring unit that measures the measured amount of the clamping object based on the detected amount detected by the clamp sensor.

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