Patent Description:
Conventionally, as this type of clamp sensor, for example, a clamp sensor described in Patent Literature <NUM> (<CIT>) is known. Patent Literature <NUM> describes a structure of pivoting a pair of clamp arms (also referred to as clip pieces) having different lengths from a pivoting axis about the pivoting axis in directions approaching each other to clamp an electric wire being a measurement object between the pair of clamp arms. According to this structure, it is possible to more reliably clamp a plurality of types of electrical wires having different diameters and measure a measurement amount of the electrical wire, for example, a voltage applied to the electrical wire and a current flowing through the electrical wire.

Patent Literature <NUM> (<CIT>) describes a clamp type electromagnetic field sensor for measuring the current flowing through a conductor or the voltage applied to it.

It may be required to surround the outer periphery of the electric wire under measurement with an electromagnetic wave shield or an electrode. In this case, in the clamp sensor described in Patent Literature <NUM>, each clamp arm is provided with an electromagnetic wave shield or an electrode. However, in the clamp sensor described in Patent Literature <NUM>, when the diameter of the electric wire is large, the pair of clamp arms is separated from each other. Accordingly, a gap is generated between the electromagnetic wave shields or the electrodes provided in the respective clamp arms. As a result, there is a possibility that the shield performance is deteriorated due to the influence of the noise through the gap or the measurement accuracy of the electric wire through the electrode is deteriorated.

Thus, for example, it is conceivable to provide a third clamp arm for surrounding the outer periphery of the electric wire. The third clamp arm forms a cylindrical shape having an inner diameter larger than the maximum diameter of an electric wire that can be clamped by the clamp sensor by making contact with one of the pair of clamp arms. Accordingly, the outer periphery of the electric wire can be surrounded by a shield or an electrode provided on the third clamp arm and the shield or the electrode provided on one of the pair of clamp arms regardless of the diameter of the electric wire.

However, the third clamp arm is a separate member from the pair of clamp arms. Therefore, a means for preventing a contact failure between the shield or the electrode provided on the third clamp arm and the shield or the electrode provided on one of the pair of clamp arms is required. For example, it is conceivable to connect two shields or electrodes with a cable disposed outside the clamp arm. However, the cable may inhibit the motion of the clamp arm.

Therefore, an object of the present invention is to solve the above problem, and to provide a clamp sensor capable of reducing a possibility of contact failure between two conductors surrounding an outer periphery of a measurement object.

In order to achieve the object, the present invention is configured as follows.

A clamp sensor according to an aspect of the present invention includes: a first clamp arm configured to pivot about a pivoting axis; a second clamp arm configured to pivot about the pivoting axis, the second clamp arm configured to clamp a measurement object in cooperation with the first clamp arm; a measurement unit provided on at least one of the first clamp arm and the second clamp arm, the measurement unit configured to measure a measured amount of the measurement object clamped by the first clamp arm and the second clamp arm; a first conductor provided on the first clamp arm so as to face an outer circumferential surface of the measurement object clamped by the first clamp arm and the second clamp arm, the first conductor including a first contact portion configured to come into contact with and separate from the second clamp arm; and a second conductor provided on the second clamp arm so as to face an outer circumferential surface of the measurement object clamped by the first clamp arm and the second clamp arm, the second conductor including a second contact portion configured to come into contact with and separate from the first contact portion. One of the first contact portion and the second contact portion comprises a leaf spring portion protruding in a width direction parallel to the pivoting axis and inclined with respect to the width direction so as to approach other of the first contact portion and the second contact portion. The first contact portion and the second contact portion come into contact with each other in a state where one of the first contact portion and the second contact portion is pressed by the other and the leaf spring portion is bent by elastic deformation.

According to the present invention, it is possible to reduce the possibility of contact failure between two conductors surrounding the outer circumference of the measurement object.

According to this configuration, the first contact portion of the first conductor and the second contact portion of the second conductor are not only in contact with each other, but one of the first contact portion and the second contact portion presses the other. Accordingly, between the first conductor and the second conductor, an elastic force against the counterpart acts. As a result, the contact strength between the first conductor and the second conductor increases. As a result, the possibility of contact failure between the first conductor and the second conductor can be reduced.

In the clamp sensor, the first contact portion may be positioned at a tip portion of the first clamp arm. The second contact portion may be positioned at a tip portion of the second clamp arm.

The tip portions of the first clamp arm and the second clamp arm are farther away from the pivoting axis than the base end portion. Therefore, the elastic force when the tip portions of the first clamp arm and the second clamp arm are in contact with each other can be made larger than the elastic force when the base end portions of the first clamp arm and the second clamp arm are in contact with each other. That is, according to this configuration, the elastic force acting between the first contact portion and the second contact portion can be increased. Accordingly, the contact strength between the first contact portion and the second contact portion can be increased.

In the clamp sensor, the first conductor may include a plurality of the first contact portions. The second conductor may include a plurality of the second contact portions provided on a one-by-one basis correspondingly to each of the plurality of first contact portions.

According to this configuration, even if a contact failure occurs in a part of the plurality of first contact portions and the second contact portions, the remaining first contact portions and the second contact portions are in contact with each other, so that a contact failure between the first conductor and the second conductor can be avoided.

In the clamp sensor, the first conductor may be formed by coating the first clamp arm with a conductive material. The second conductor may be formed by coating the second clamp arm with a conductive material.

According to this configuration, since it is not necessary to arrange a conductive member on the first clamp arm and the second clamp arm, the number of components included in the first clamp arm and the second clamp arm can be reduced.

In the clamp sensor, at least one of the first clamp arm and the second clamp arm may include a projection. The projection may be provided at the same position as the first contact portion and the second contact portion in an insertion direction of the measurement object into the clamp sensor when the measurement object is clamped by the first clamp arm and the second clamp arm, or at a position upstream of the first contact portion and the second contact portion in the insertion direction. The projection included in the first clamp arm may protrude more toward the second contact portion than toward the first contact portion as viewed from a width direction parallel to the pivoting axis. The projection included in the second clamp arm may protrude more toward the first contact portion than toward the second contact portion as viewed from the width direction.

According to this configuration, the projection is positioned at the same position in the insertion direction as the first contact portion and the second contact portion or upstream of the first contact portion and the second contact portion in the insertion direction. In addition, the projection protrudes larger than the first contact portion and the second contact portion. Therefore, when the measurement object is inserted along the insertion direction between the first clamp arm and the second clamp arm, the projection can inhibit the measurement object from coming into contact with the first contact portion and the second contact portion. Accordingly, it is possible to reduce the possibility that the first contact portion and the second contact portion are worn or damaged by coming into contact with the measurement object.

In the clamp sensor, the first conductor and the second conductor may have an electromagnetic wave shielding function for the measurement object clamped by the first clamp arm and the second clamp arm.

According to this configuration, the outer circumferential surface of the measurement object can be largely surrounded in the circumferential direction by the electromagnetic wave shield including the first conductor and the second conductor connected to each other. Therefore, it is possible to enhance the shielding effect against the electromagnetic wave that may affect the measurement object.

In the clamp sensor, the first conductor and the second conductor may be electrodes functioning as the measurement units.

According to this configuration, the electrodes including the first conductor and the second conductor connected to each other can largely surround the outer circumferential surface of the measurement object in the circumferential direction. Therefore, the measurement accuracy by the measurement unit can be improved.

In the clamp sensor, the first conductor may include: a first shield conductor having an electromagnetic wave shielding function for the measurement object clamped by the first clamp arm and the second clamp arm; and a first electrode functioning as the measurement unit. The second conductor may include: a second shield conductor having an electromagnetic wave shielding function for the measurement object clamped by the first clamp arm and the second clamp arm; and a second electrode functioning as the measurement unit. Each of the first shield conductor and the first electrode may include the first contact portion. Each of the second shield conductor and the second electrode may include the second contact portion. The first contact portion of the first shield conductor and the second contact portion of the second shield conductor may come into contact with each other and separate from each other. The first contact portion of the first electrode and the second contact portion of the second electrode may come into contact with each other and separate from each other.

According to this configuration, the outer circumference of the measurement object can be largely surrounded by the electromagnetic wave shield including the first contact portion and the second contact portion connected to each other. Therefore, it is possible to enhance the shielding effect against the electromagnetic wave that may affect the measurement object.

According to this configuration, the outer circumference of the measurement object can be largely surrounded by the electrodes including the first contact portion and the second contact portion connected to each other. Therefore, the measurement accuracy by the measurement unit can be improved.

In the clamp sensor, as viewed from a width direction parallel to the pivoting axis, the first contact portion of the first shield conductor and the second contact portion of the second shield conductor may be positioned on one of an opposite side from the pivoting axis with respect to a clamping position at which the measurement object is clamped by the first clamp arm and the second clamp arm and the pivoting axis side with respect to the clamping position. As viewed from the width direction, the first contact portion of the first electrode and the second contact portion of the second electrode may be positioned on the other of an opposite side from the pivoting axis with respect to the clamping position and the pivoting axis side with respect to the clamping position.

According to this configuration, the first contact portion of the first shield conductor and the second contact portion of the second shield conductor, and the first contact portion of the first electrode and the second contact portion of the second electrode are positioned on sides opposite to each other across a clamping position. Therefore, the arrangement space of the contact portion of the shield conductor and the arrangement space of the contact portion of the electrode are not reduced by the arrangement space of the counterpart.

When the distance between the shield conductor and the electrode is too small, the shielding performance and the measurement accuracy may be deteriorated. However, according to this configuration, it is easy to increase the distance between the shield conductor and the electrode. When the distance is large, it is possible to avoid deterioration of the shielding performance and the measurement accuracy.

<FIG> is a perspective view of a clamp sensor according to an embodiment of the present invention. <FIG> is an exploded perspective view of the clamp sensor according to the embodiment of the present invention. <FIG> is a perspective view of the clamp sensor in which the cover member is removed from <FIG>.

As shown in <FIG>, the clamp sensor <NUM> according to the present embodiment includes clamp arms <NUM>, <NUM>, and <NUM> and a shaft <NUM>. The clamp arm <NUM> is an example of a first clamp arm. The clamp arm <NUM> is an example of a second clamp arm.

The clamp arms <NUM> and <NUM> are configured to be able to clamp the measurement object <NUM> in cooperation with each other. The clamp arms <NUM> and <NUM> are configured to be able to clamp the measurement object <NUM> while covering the outer circumferential surface 60A of the measurement object <NUM> in cooperation with each other. In the present embodiment, the measurement object <NUM> is an electric wire. It should be noted that the clamp sensor <NUM> according to the present embodiment can clamp a plurality of types of electric wires having different diameters.

The clamp arm <NUM> is configured to pivot about a pivoting axis <NUM>. In the present embodiment, the shaft <NUM> passes through the through hole 21A provided in the clamp arm <NUM>. The pivoting axis <NUM> is an imaginary line passing through the center of the shaft <NUM>. In the present embodiment, the clamp arm <NUM> is biased by a biasing member (not shown) such as a torsion coil spring so as to pivot in a direction approaching the clamp arm <NUM> about the pivoting axis <NUM>.

The clamp arm <NUM> includes a main body portion <NUM> and a pair of arm portions <NUM> protruding from the main body portion <NUM>. The respective arm portions <NUM> protrude from both end portions of the main body portion <NUM> in the width direction <NUM> parallel to the pivoting axis <NUM>. Each arm portion <NUM> has the above-described through hole 21A and a pressing surface 21B. The pressing surface 21B is curved in an arc shape as viewed from the width direction <NUM>. The curvature of the pressing surface 21B is set in accordance with the diameter of the measurement object <NUM> (for example, equal to or slightly larger than the diameter of the measurement object <NUM>).

The clamp arm <NUM> is configured to pivot about the pivoting axis <NUM>. In the present embodiment, the clamp arm <NUM> is provided between the pair of arm portions <NUM> of the clamp arm <NUM>. The shaft <NUM> passes through the through hole 31A provided in the clamp arm <NUM>. In the present embodiment, the clamp arm <NUM> is biased by a biasing member (not shown) such as a torsion coil spring so as to pivot in a direction approaching the clamp arm <NUM> about the pivoting axis <NUM>.

The clamp arm <NUM> has a pair of protrusions <NUM>. Each protrusion <NUM> has the above-described through hole 31A. One of the pair of protrusions <NUM> has a protruding portion 31B. The protruding portion 31B is opposed to the main body portion <NUM> of the clamp arm <NUM> in a pivoting direction (a circumferential direction around the pivoting axis <NUM>) of the clamp arms <NUM>, <NUM>, and <NUM>. When the main body portion <NUM> of the pivoting clamp arm <NUM> presses the protrusion <NUM>, the clamp arm <NUM> pivots.

The clamp arm <NUM> includes a cover member <NUM>, a pair of projections <NUM>, and a projection <NUM>.

The cover member <NUM> covers the projection <NUM>. The cover member <NUM> is attachable to and detachable from the clamp arm <NUM>. In <FIG> and <FIG>, the cover member <NUM> is attached to the clamp arm <NUM>. In <FIG>, the cover member <NUM> is detached from the clamp arm <NUM>.

The projections <NUM> and <NUM> are provided at the tip portion <NUM> of the clamp arm <NUM>. The tip portion <NUM> of the clamp arm <NUM> is a portion farthest from the pivoting axis <NUM> in the radial direction orthogonal to the pivoting axis <NUM>, in the clamp arm <NUM>. The projections <NUM> and <NUM> protrude to approach the clamp arm <NUM> about the pivoting axis <NUM>. The pair of projections <NUM> is provided at an interval in the width direction <NUM>. The projection <NUM> is provided between the pair of projections <NUM> in the width direction <NUM>. It should be noted that the positional relationship between the projections <NUM> and <NUM> is not limited to the above, and for example, the projection <NUM> may be provided outside the pair of projections <NUM> in the width direction <NUM>.

<FIG> is a perspective cross-sectional view of the clamp sensor according to the embodiment of the present invention. <FIG> is a right side view of <FIG>.

As shown in <FIG> and <FIG>, the clamp arm <NUM> is provided with a first shield conductor 30A and a first electrode <NUM>. Each of the first shield conductor 30A and the first electrode <NUM> is an example of a first conductor.

In the present embodiment, the first shield conductor 30A is a conductive coating material (coating material containing a conductive material) applied over the inner surface of the clamp arm <NUM> and the tip surfaces 34A of the pair of projections <NUM>. The first shield conductor 30A is formed so as to cover a part of the outer circumferential surface 60A of the measurement object <NUM> clamped by the clamp arms <NUM> and <NUM>. That is, the first shield conductor 30A is provided on the clamp arm <NUM> so as to face the outer circumferential surface 60A of the measurement object <NUM> clamped between the clamp arms <NUM> and <NUM>.

The conductive coating material applied to the tip surfaces 34A of the pair of projections <NUM> is electrically connected to the conductive coating material applied to the other portion (the conductive coating material applied to the inner surface of the clamp arm <NUM>). The first shield conductor 30A has a first contact portion 30Aa. The first contact portion 30Aa includes the pair of projections <NUM> and a conductive coating material (first shield conductor 30A) applied to the tip surface 34A of each of the pair of projections <NUM>. That is, in the present embodiment, the first shield conductor 30A includes a plurality of first contact portions 30Aa.

In the present embodiment, the first electrode <NUM> is a conductive plate disposed inside the clamp arm <NUM>. The first electrode <NUM> includes an arc-shaped portion 71A and a protruding portion 71B.

The arc-shaped portion 71A is curved in an arc shape as viewed from the width direction <NUM>. The curvature of the arc-shaped portion 71A is set in accordance with the diameter of the measurement object <NUM> (for example, equal to or slightly larger than the diameter of the measurement object <NUM>). The arc-shaped portion 71A covers a part of the outer circumferential surface 60A of the measurement object <NUM>. As shown in <FIG>, in the end portion in the circumferential direction of the arc-shaped portion 71A, the one end portion 71Aa in the circumferential direction of the arc-shaped portion 71A is positioned on the opposite side of the shaft <NUM> (in other words, the pivoting axis <NUM>) with respect to the clamping position of the measurement object <NUM>. The clamping position of the measurement object <NUM> is a position where the measurement object <NUM> is clamped between the clamp arms <NUM> and <NUM> and the clamp arm <NUM>. In the end portion in the circumferential direction of the arc-shaped portion 71A, the other end portion 71Ab in the circumferential direction of the arc-shaped portion 71A is positioned on the shaft <NUM> side with respect to the clamping position of the measurement object <NUM>. That is, the other end portion 71Ab in the circumferential direction of the arc-shaped portion 71A is positioned between the clamping position of the measurement object <NUM> and the shaft <NUM>. The protruding portion 71B protrudes toward the shaft <NUM> from the other end portion 71Ab in the circumferential direction of the arc-shaped portion 71A.

It should be noted that the first shield conductor 30A is not limited to the conductive coating material, and the first electrode <NUM> is not limited to the conductive plate. For example, the first shield conductor 30A may be a conductive plate disposed inside the clamp arm <NUM>.

As shown in <FIG>, the clamp arm <NUM> is configured to pivot about the pivoting axis <NUM>. In the present embodiment, the clamp arm <NUM> is provided to face the clamp arms <NUM> and <NUM> in the pivoting direction of the clamp arms <NUM>, <NUM>, and <NUM>. The shaft <NUM> passes through the through hole 41A provided in the clamp arm <NUM>.

The clamp arm <NUM> has a pair of protrusions <NUM>. Each protrusion <NUM> has the above-described through hole 41A. The clamp arm <NUM> has receiving surfaces 40B at both end portions in the width direction <NUM>. The receiving surface 40B is curved in an arc shape as viewed from the width direction <NUM>. The curvature of the receiving surface 40B is set in accordance with the diameter of the measurement object <NUM> (for example, equal to or slightly larger than the diameter of the measurement object <NUM>). The receiving surface 40B faces the pressing surface 21B of the clamp arm <NUM> in the pivoting direction, and can clamp the measurement object <NUM> between the receiving surface 40B and the pressing surface 21B.

The clamp arm <NUM> includes a cover member <NUM>, a pair of leaf spring portions <NUM>, and a recess <NUM>.

The cover member <NUM> covers the leaf spring portion <NUM>. The cover member <NUM> is attachable to and detachable from the clamp arm <NUM>. In <FIG> and <FIG>, the cover member <NUM> is attached to the clamp arm <NUM>. In <FIG>, the cover member <NUM> is detached from the clamp arm <NUM>.

The leaf spring portion <NUM> and the recess <NUM> are provided at the tip portion <NUM> of the clamp arm <NUM>. The tip portion <NUM> of the clamp arm <NUM> is a portion farthest from the pivoting axis <NUM> in the radial direction orthogonal to the pivoting axis <NUM>, in the clamp arm <NUM>. Each of the pair of leaf spring portions <NUM> faces a corresponding one of the pair of projections <NUM> in the pivoting direction. Each of the pair of leaf spring portions <NUM> protrudes outward in the width direction <NUM> from the tip portion <NUM>. Each of the pair of leaf spring portions <NUM> is inclined with respect to the width direction <NUM> so as to approach the projection <NUM> as it goes outward in the width direction <NUM>. The leaf spring portion <NUM> can be bent in the pivoting direction by elastic deformation.

The recess <NUM> is provided between the pair of leaf spring portions <NUM> in the width direction <NUM>. The recess <NUM> faces the projection <NUM> in the pivoting direction. The projection <NUM> can be fitted into the recess <NUM> (see <FIG> and <FIG>).

As shown in <FIG> and <FIG>, the clamp arm <NUM> is provided with a second shield conductor 40A and a second electrode <NUM>. Each of the second shield conductor 40A and the second electrode <NUM> is an example of a second conductor.

In the present embodiment, the second shield conductor 40A is a conductive coating material applied over the inner surface of the clamp arm <NUM> and the opposing surfaces 44A of the pair of leaf spring portions <NUM>. Among the surfaces of the pair of leaf spring portions <NUM>, the opposing surfaces 44A of the pair of leaf spring portions <NUM> are surfaces facing the tip surface 34A of the projection <NUM> in the pivoting direction. The second shield conductor 40A is formed so as to cover a part of the outer circumferential surface 60A of the measurement object <NUM> clamped by the clamp arms <NUM> and <NUM>. That is, the second shield conductor 40A is provided on the clamp arm <NUM> so as to face the outer circumferential surface 60A of the measurement object <NUM> clamped between the clamp arms <NUM> and <NUM>.

The conductive coating material applied to the opposing surfaces 44A of the pair of leaf spring portions <NUM> is electrically connected to the conductive coating material applied to the other portion (the conductive coating material applied to the inner surface of the clamp arm <NUM>). The second shield conductor 40A has a second contact portion 40Aa. The second contact portion 40Aa includes the pair of leaf spring portions <NUM> and a conductive coating material (second shield conductor 40A) applied to the opposing surface 44A of each of the pair of leaf spring portions <NUM>. That is, in the present embodiment, the second shield conductor 40A includes the plurality of second contact portions 40Aa provided on a one-by-one basis correspondingly to each of the plurality of first contact portions 30Aa.

In the present embodiment, the second electrode <NUM> is a conductive plate disposed inside the clamp arm <NUM>. The second electrode <NUM> includes an arc-shaped portion 72A and protruding portions 72B and 72C.

The arc-shaped portion 72A is curved in an arc shape as viewed from the width direction <NUM>. The curvature of the arc-shaped portion 72A is set in accordance with the diameter of the measurement object <NUM> (for example, equal to or slightly larger than the diameter of the measurement object <NUM>). The arc-shaped portion 72A covers a part of the outer circumferential surface 60A of the measurement object <NUM> from the opposite side from the arc-shaped portion 71A of the first electrode <NUM>. That is, the second electrode <NUM> clamps the measurement object <NUM> between the second electrode <NUM> and the first electrode <NUM>. As shown in <FIG>, in the end portion in the circumferential direction of the arc-shaped portion 72A, the one end portion 72Aa in the circumferential direction of the arc-shaped portion 72A is positioned on the opposite side of the shaft <NUM> (in other words, the pivoting axis <NUM>) with respect to the clamping position of the measurement object <NUM>. In the end portion in the circumferential direction of the arc-shaped portion 72A, the other end portion in the circumferential direction of the arc-shaped portion 72A is positioned on the shaft <NUM> side with respect to the clamping position of the measurement object <NUM>. That is, the other end portion in the circumferential direction of the arc-shaped portion 72A is positioned between the clamping position of the measurement object <NUM> and the shaft <NUM>. The protruding portion 72B protrudes toward the shaft <NUM> from the other end portion in the circumferential direction of the arc-shaped portion 72A.

The protruding portion 72C is provided adjacent to the protruding portion 72B in the width direction <NUM>. The protruding portion 72C protrudes from the other end portion in the circumferential direction of the arc-shaped portion 72A. The protruding portion 72C protrudes in a direction away from the clamp arm <NUM> as viewed from the width direction <NUM>. The protruding portion 72C is electrically connected to the printed circuit board <NUM> disposed inside the clamp arm <NUM>. The printed circuit board <NUM> is mounted with various electronic components constituting a circuit for measuring the measured amount of the measurement object <NUM>. In the present embodiment, the measured amount is a voltage applied to the measurement object <NUM> (electric wire) or a current flowing through the measurement object <NUM> (electric wire).

It should be noted that the second shield conductor 40A is not limited to the conductive coating material, and the second electrode <NUM> is not limited to the conductive plate. For example, the second shield conductor 40A may be a conductive plate disposed inside the clamp arm <NUM>.

The first contact portion 30Aa and the second contact portion 40Aa can be in contact with each other (see <FIG>) and separated from each other (see <FIG>).

In a state where the clamp arms <NUM> and <NUM> are opened with respect to the clamp arm <NUM> (see <FIG>), the first contact portion 30Aa and the second contact portion 40Aa are separated from each other.

On the other hand, as shown in <FIG>, in a state where the clamp arms <NUM> and <NUM> clamp the measurement object <NUM>, the first contact portion 30Aa and the second contact portion 40Aa come into contact with each other. At this time, the tip surface 34A of the projection <NUM> being a part of the first contact portion 30Aa presses the opposing surface 44A of the leaf spring portion <NUM> being a part of the second contact portion 40Aa in the pivoting direction. Accordingly, the leaf spring portion <NUM> is bent in the pivoting direction by elastic deformation. As a result, the first contact portion 30Aa (specifically, the first shield conductor 30A coated on the tip surface 34A of the projection <NUM>) and the second contact portion 40Aa (specifically, the second shield conductor 40A coated on the opposing surface 44A of the leaf spring portion <NUM>) come into contact with each other in a state where the second contact portion 40Aa is pressed by the first contact portion 30Aa and bent by elastic deformation. With the above, the first shield conductor 30A and the second shield conductor 40A are electrically connected to each other.

In the present embodiment, the second shield conductor 40A is grounded. In other words, the second shield conductor 40A is electrically connected to the ground. Therefore, the first shield conductor 30A electrically connected to the second shield conductor 40A is also grounded. Here, the first shield conductor 30A and the second shield conductor 40A face the outer circumferential surface 60A of the measurement object <NUM> clamped by the clamp arms <NUM> and <NUM> and surround the outer circumferential surface 60A. With the above configuration, the first shield conductor 30A and the second shield conductor 40A have an electromagnetic wave shielding function with respect to the measurement object <NUM> clamped by the clamp arms <NUM> and <NUM>. It should be noted that the first shield conductor 30A may be grounded instead of the second shield conductor 40A, or both the first shield conductor 30A and the second shield conductor 40A may be grounded.

It should be noted that in the present embodiment, the first shield conductor 30A and the second shield conductor 40A are in contact with each other at the tip portions <NUM> and <NUM>, but are not in contact with each other on the opposite side from the tip portions <NUM> and <NUM> with respect to the clamping position of the measurement object <NUM>. However, the first shield conductor 30A and the second shield conductor 40A may be in contact with each other on the opposite side.

The first electrode <NUM> and the second electrode <NUM> shown in <FIG> and <FIG> can be in contact with each other and can be separated from each other.

In a state where the clamp arms <NUM> and <NUM> are opened with respect to the clamp arm <NUM> (see <FIG>), the first electrode <NUM> and the second electrode <NUM> are separated from each other.

On the other hand, as shown in <FIG> and <FIG>, in a state where the clamp arms <NUM> and <NUM> clamp the measurement object <NUM>, the first electrode <NUM> and the second electrode <NUM> come into contact with each other. Specifically, one end portion 71Aa in the circumferential direction of the arc-shaped portion 71A of the first electrode <NUM> is in contact with and electrically connected to one end portion 72Aa in the circumferential direction of the arc-shaped portion 72A of the second electrode <NUM>. In addition, the protruding portion 71B of the first electrode <NUM> is in contact with and electrically connected to the protruding portion 72B of the second electrode <NUM>. Accordingly, the first electrode <NUM> and the second electrode <NUM> completely surround the measurement object <NUM> as viewed from the width direction <NUM>.

In the present embodiment, the measurement object <NUM> is an electric wire, and the electric wire includes a conductor and a covering portion covering the conductor. The first electrode <NUM> and the second electrode <NUM> face the conductor of the electric wire across the covering portion of the electric wire. That is, the first electrode <NUM> and the second electrode <NUM> are capacitively coupled to the measurement object <NUM> (specifically, the conductor of the electric wire), and function as a voltage detection element configured to measure the voltage (measured amount) applied to the conductor of the electric wire clamped by the clamp arms <NUM> and <NUM> in a non-contact manner. That is, the first electrode <NUM> and the second electrode <NUM> are an example of a measurement unit and an example of an electrode functioning as a measurement unit.

<FIG> is a perspective view of a first clamp arm. As shown in <FIG>, the first electrode <NUM> includes a leaf spring portion 71C. The leaf spring portions 71C are provided at both end portions in the width direction <NUM> of the protruding portion 71B. The leaf spring portion 71C extends outward in the width direction <NUM> from the protruding portion 71B. The leaf spring portion 71C is inclined with respect to the width direction <NUM> so as to approach the protruding portion 72B of the second electrode <NUM> as it goes outward in the width direction <NUM>. The leaf spring portion 71C can be bent in the pivoting direction by elastic deformation.

<FIG> is a perspective cross-sectional view of the clamp sensor according to the embodiment of the present invention. As shown in <FIG>, each of the pair of leaf spring portions 71C of the first electrode <NUM> and the protruding portion 72B of the second electrode <NUM> can come into contact with each other. For example, in a state where the clamp arms <NUM> and <NUM> clamp the measurement object <NUM>, each of the pair of leaf spring portions 71C and the protruding portion 72B come into contact with each other. At this time, the protruding portion 72B presses the pair of leaf spring portions 71C in the pivoting direction. Accordingly, the pair of leaf spring portions 71C is bent in the pivoting direction by elastic deformation. As a result, the protruding portion 72B and the pair of leaf spring portions 71C come into contact with each other in a state where the pair of leaf spring portions 71C is pressed by the protruding portion 72B and is bent by elastic deformation. With the above, the first electrode <NUM> and the second electrode <NUM> are electrically connected to each other. The pair of leaf spring portions 71C is an example of the first contact portion, and the protruding portion 72B is an example of the second contact portion.

The first electrode <NUM> and the second electrode <NUM> are in contact with each other on both sides of the clamping position of the measurement object <NUM>. Accordingly, as described above, the first electrode <NUM> and the second electrode <NUM> completely surround the measurement object <NUM> as viewed from the width direction <NUM>. Here, by increasing the contact pressure (in other words, the contact pressure of the one end portion 71Aa and the one end portion 72Aa) on the opposite side of the shaft <NUM> (pivoting axis <NUM>) with respect to the clamping position of the measurement object <NUM>, the reliability of the contact of the one end portions 71Aa and 72Aa is improved. However, in this case, with respect to the clamping position of the measurement object <NUM>, the contact pressure on the shaft <NUM> side (in other words, the contact pressure of the protruding portion 71B and the protruding portion 72B) becomes low, and the reliability of the contact of the protruding portions 71B and 72B may decrease. However, in the present embodiment, even if the reliability of contact of the protruding portions 71B and 72B decreases, the reliability of contact between the leaf spring portion 71C and the protruding portion 72B can be favorably maintained.

As described above, as viewed from the width direction <NUM>, the first contact portion 30Aa of the first shield conductor 30A and the second contact portion 40Aa of the second shield conductor 40A are positioned on the opposite side from the shaft <NUM> (the pivoting axis <NUM>) with respect to the clamping position of the measurement object <NUM> as shown in <FIG>. On the other hand, as viewed from the width direction <NUM>, the pair of leaf spring portions 71C corresponding to the first contact portion of the first electrode <NUM> and the protruding portion 72B corresponding to the second contact portion of the second electrode <NUM> are positioned on the shaft <NUM> side with respect to the clamping position of the measurement object <NUM> as shown in <FIG> and <FIG>. That is, the first contact portion 30Aa of the first shield conductor 30A and the second contact portion 40Aa of the second shield conductor 40A, and the first contact portion of the first electrode <NUM> and the second contact portion of the second electrode <NUM> are positioned on the sides opposite to each other across the clamping position of the measurement object <NUM>.

It should be noted that in contrast to the above, as. viewed from the width direction <NUM>, the first contact portion 30Aa of the first shield conductor 30A and the second contact portion 40Aa of the second shield conductor 40A may be positioned on the shaft <NUM> side with respect to the clamping position of the measurement object <NUM>. In addition, as viewed from the width direction <NUM>, the pair of leaf spring portions 71C of the first electrode <NUM> and the protruding portion 72B of the second electrode <NUM> may be positioned on the opposite side from the shaft <NUM> with respect to the clamping position of the measurement object <NUM>.

In addition, both the first contact portion 30Aa of the first shield conductor 30A and the second contact portion 40Aa of the second shield conductor 40A, and the first contact portion of the first electrode <NUM> and the second contact portion of the second electrode <NUM> may be positioned on the same side with respect to the clamping position of the measurement object <NUM> (for example, both are on the opposite side from the shaft <NUM> with respect to the clamping position of the measurement object <NUM>).

<FIG> is a perspective view of the clamp sensor according to the embodiment of the present invention. <FIG> is a right side view of the clamp sensor according to the embodiment of the present invention.

As shown in <FIG>, the projection <NUM> is provided at a position upstream of the first contact portion 30Aa and the second contact portion 40Aa in the insertion direction <NUM>, in the insertion direction <NUM> of the measurement object <NUM> into the clamp sensor <NUM> when the measurement object <NUM> is clamped by the clamp arms <NUM> and <NUM>.

As shown in <FIG> and <FIG>, the projection <NUM> included in the clamp arm <NUM> protrudes more to the second contact portion 40Aa side than to the first contact portion 30Aa as viewed from the width direction <NUM>.

It should be noted that the projection <NUM> may be provided at the same position as the first contact portion 30Aa and the second contact portion 40Aa in the insertion direction <NUM>. In addition, the projection <NUM> may be provided on the clamp arm <NUM>. In this case, the projection <NUM> protrudes more to the first contact portion 30Aa side than to the second contact portion 40Aa as viewed from the width direction <NUM>.

According to the present embodiment, the first contact portion 30Aa and the second contact portion 40Aa are not only in contact with each other, but one of the first contact portion and the second contact portion presses the other. Accordingly, between the first shield conductor 30A and the second shield conductor 40A, an elastic force against the counterpart acts. As a result, the contact strength between the first shield conductor 30A and the second shield conductor 40A increases. As a result, the possibility of contact failure between the first shield conductor 30A and the second shield conductor 40A can be reduced.

According to the present embodiment, the pair of leaf spring portions 71C and the protruding portion 72B are not only in contact with each other, but one of the first contact portion and the second contact portion presses the other. Accordingly, between the first electrode <NUM> and the second electrode <NUM>, an elastic force against the counterpart acts. As a result, the contact strength between the first electrode <NUM> and the second electrode <NUM> increases. As a result, the possibility of contact failure between the first electrode <NUM> and the second electrode <NUM> can be reduced.

The tip portion <NUM> of the clamp arm <NUM> and the tip portion <NUM> of the clamp arm <NUM> are farther away from the pivoting axis <NUM> than the base end portion (the end portion of the pivoting axis side <NUM>). Therefore, the elastic force when the tip portions <NUM> and <NUM> of the clamp arms <NUM> and <NUM> are in contact with each other can be made larger than the elastic force when the base end portions of the clamp arms <NUM> and <NUM> are in contact with each other. That is, according to the present embodiment, the elastic force acting between the first contact portion 30Aa and the second contact portion 40Aa can be increased. Accordingly, the contact strength between the first contact portion 30Aa and the second contact portion 40Aa can be increased.

According to the present embodiment, the clamp sensor <NUM> has two sets of the projections <NUM> and the leaf spring portions <NUM>. Even if a contact failure occurs between the conductive paints painted on each of the projections <NUM> and the leaf spring portions <NUM> of one of the two sets, the other projections <NUM> and the leaf spring portions <NUM> of the two sets are in contact with each other, so that a contact failure between the first shield conductor 30A and the second shield conductor 40A can be avoided.

According to the present embodiment, the first shield conductor 30A and the second shield conductor 40A are conductive coating material. Therefore, since it is not necessary to arrange a conductive member on the clamp arms <NUM> and <NUM>, the number of components included in the clamp arms <NUM> and <NUM> can be reduced.

According to the present embodiment, the projection <NUM> is positioned upstream of the pair of projections <NUM> in the insertion direction <NUM>. In addition, the projection <NUM> protrudes larger than the pair of projections <NUM>. Therefore, when the measurement object <NUM> is inserted along the insertion direction <NUM> between the clamp arms <NUM> and <NUM>, the projection <NUM> can inhibit the measurement object <NUM> from coming into contact with the pair of projections <NUM>. For example, as shown in <FIG>, the measurement object <NUM> to be inserted contacts with the projection <NUM> but not the projection <NUM>. Accordingly, it is possible to reduce the possibility that the pair of projections <NUM> are worn or damaged by coming into contact with the measurement object <NUM>.

According to the present embodiment, the outer circumferential surface 60A of the measurement object <NUM> can be largely surrounded in the circumferential direction by the electromagnetic wave shield including the first shield conductor 30A and the second shield conductor 40A connected to each other. Therefore, it is possible to enhance the shielding effect against the electromagnetic wave that may affect the measurement object <NUM>.

According to the present embodiment, the first electrode <NUM> and the second electrode <NUM> connected to each other can largely surround the outer circumferential surface 60A of the measurement object <NUM> in the circumferential direction. Therefore, the measurement accuracy by the first electrode <NUM> and the second electrode <NUM> can be improved.

In the present embodiment, the measurement units (the first electrode <NUM> and the second electrode <NUM>) are provided in both the clamp arms <NUM> and <NUM>. However, the measurement units may be provided only on one of the clamp arms <NUM> and <NUM>. For example, the clamp sensor <NUM> may include only one of the first electrode <NUM> and the second electrode <NUM>.

In the present embodiment, the first shield conductor 30A and the second shield conductor 40A include a first contact portion 30Aa and a second contact portion 40Aa, and the first electrode <NUM> and the second electrode <NUM> include a first contact portion (a pair of leaf spring portions 71C) and a second contact portion (a protruding portion 72B). However, the first contact portion and the second contact portion may be provided on only one of the first shield conductor 30A and second shield conductor 40A and the first electrode <NUM> and second electrode <NUM>. For example, the first electrode <NUM> and the second electrode <NUM> do not need to include the pair of leaf spring portions 71C corresponding to the first contact portion.

In contrast to the present embodiment, the projection <NUM> may be provided on the clamp arm <NUM>, and the pair of leaf spring portions <NUM> may be provided on the clamp arm <NUM>.

In the present embodiment, the first electrode <NUM> includes the pair of leaf spring portions 71C, but the second electrode <NUM> may include the pair of leaf spring portions 71C. In this case, the protruding portion 71B presses the pair of leaf spring portions 71C in the pivoting direction.

The configurations of the first contact portion and the second contact portion are not limited to the configuration described in the present embodiment. That is, as long as one of the first contact portion and the second contact portion is pressed by the other, and the first contact portion and the second contact portion are in contact with each other in a state where at least one of the one and the other is bent by elastic deformation, various configurations are applicable as the first contact portion and the second contact portion.

For example, in the present embodiment, the first contact portion 30Aa and the second contact portion 40Aa come into contact with each other in a state where the second contact portion 40Aa is pressed by the first contact portion 30Aa and the second contact portion 40Aa is bent by elastic deformation. However, in contrast to the above, the first contact portion and the second contact portion may come into contact with each other in a state where the first contact portion is pressed by the second contact portion and the first contact portion is bent by elastic deformation. In addition, the first contact portion and the second contact portion may be in contact with each other in a state where both the first contact portion and the second contact portion are pressed against each other and are bent by elastic deformation.

The present invention has been sufficiently described in connection with the preferable embodiment with reference to the drawings as appropriate, but various modifications and corrections are apparent for those skilled in the art. It should be understood that as long as such modifications and corrections do not depart from the scope of the present invention by the attached claims, they are included therein.

Claim 1:
A clamp sensor (<NUM>) comprising:
a first clamp arm (<NUM>) configured to pivot about a pivoting axis (<NUM>);
a second clamp arm (<NUM>) configured to pivot about the pivoting axis (<NUM>), the second clamp arm (<NUM>) configured to clamp a measurement object (<NUM>) in cooperation with the first clamp arm (<NUM>);
a measurement unit provided on at least one of the first clamp arm (<NUM>) and the second clamp arm(<NUM>), the measurement unit configured to measure a measured amount of the measurement object (<NUM>) clamped by the first clamp arm (<NUM>) and the second clamp arm (<NUM>);
a first conductor (<NUM>) provided on the first clamp arm (<NUM>) so as to face an outer circumferential surface of the measurement object (<NUM>) clamped by the first clamp arm (<NUM>) and the second clamp arm (<NUM>), the first conductor (<NUM>) including a first contact portion (71C) configured to come into contact with and separate from the second clamp arm (<NUM>); and
a second conductor (<NUM>) provided on the second clamp arm (<NUM>) so as to face an outer circumferential surface of the measurement object (<NUM>) clamped by the first clamp arm (<NUM>) and the second clamp arm (<NUM>), the second conductor (<NUM>) including a second contact portion (72B) configured to come into contact with and separate from the first contact portion (71C), wherein
one of the first contact portion (71C) and the second contact portion (72B) comprises a leaf spring portion protruding in a width direction (<NUM>) parallel to the pivoting axis (<NUM>) and inclined with respect to the width direction (<NUM>) so as to approach other of the first contact portion (71C) and the second contact portion (72B), and wherein
the first contact portion (71C) and the second contact portion (72B) come into contact with each other in a state where one of the first contact portion (71C) and the second contact portion (72B) is pressed by the other and the leaf spring portion is bent by elastic deformation.