JP5687384B1 - Force sensor - Google Patents

Abstract

[PROBLEMS] To increase detection sensitivity while ensuring sufficient robustness. A disk-shaped inner member 110 disposed around an origin O, an annular outer member 120 disposed around an origin O, and two arc-shaped arms 130 and 140 connecting the two, Thus, the basic structure 100 is formed. The support substrate 200 is bonded to the lower surface of the outer member 120, and the fixed electrodes E1 to E12 are attached to the upper surface of the bottom plate portion 210. Measurement points H1 to H4 are defined at predetermined positions of the arc-shaped arms 130 and 140, and the fixed electrodes E1 to E8 are arranged in the vicinity thereof. The fixed electrodes E9 to E12 are disposed below the inner member 110. When an external force is applied to the inner member 110, the arc-shaped arms 130 and 140 are bent. Capacitance elements are formed by the fixed electrodes E <b> 1 to E <b> 12 and their opposing surfaces, and based on changes in the capacitance values of these capacitance elements, the forces in the coordinate axes and the moments around the coordinate axes that act on the inner member 110 are detected. [Selection] Figure 13

Description

  The present invention relates to a force sensor, and more particularly to a sensor suitable for detecting a force in each coordinate axis direction and a moment around each coordinate axis in a three-dimensional orthogonal coordinate system.

  Various types of force sensors are used to control the operation of robots and industrial machines. A small force sensor is also incorporated as a man-machine interface of an input device of an electronic device. In order to reduce the size and reduce the cost, the force sensor used for such an application has a simple structure as much as possible, and can detect the force relating to each coordinate axis in a three-dimensional space independently. Is required.

  Currently, the multi-axis force sensor that is generally used is a type that detects a specific direction component of a force acting on a mechanical structure part as a displacement generated in a specific part and a specific part. It is classified as a type to detect as mechanical strain. A typical example of the former displacement detection type is a capacitive element type force sensor, in which a capacitive element is configured by a pair of electrodes, and the displacement generated in one electrode by the applied force is detected by the capacitive element. The detection is based on the capacitance value. For example, Patent Document 1 (corresponding US publication is Patent Document 2) and Patent Document 3 (corresponding United States Publication is Patent Document 4) below disclose this capacitance-type multi-axis force sensor.

  On the other hand, a representative of the latter type of mechanical strain detection is a strain gauge type force sensor that detects mechanical strain caused by the applied force as a change in electrical resistance such as a strain gauge. is there. For example, the following Patent Document 5 (corresponding US publication is Patent Document 6) discloses this strain gauge type multi-axis force sensor.

  Various proposals have also been made on the form of the mechanical structure in order to reduce the size and thickness. For example, Patent Document 7 discloses a ring-shaped load detection unit that is generated by the action of a moment by disposing a flexible ring-shaped load detection unit on the outside of a cylindrical rigid body unit. A sensor for detecting strain is disclosed. Further, in Patent Document 8, two sets of rings, an inner ring and an outer ring, are arranged concentrically and connected between them, and the force acting on one ring is transmitted to the other ring to be deformed. A sensor for detecting a deformation mode is disclosed.

JP 2004-325367 A US Pat. No. 7,219,561 JP 2004-354049 A US Pat. No. 6,915,709 JP-A-8-122178 US Pat. No. 5,490,427 Japanese Patent Application Laid-Open No. 6-094548 Japanese Patent No. 4963138

  As described above, force sensors are used in various applications, and demand for highly sensitive sensors having a simple structure is expected. However, in the case of a force sensor that has been proposed in the past, in order to further increase the detection sensitivity, the flexible structure portion is provided so that sufficient deflection necessary for detection can be obtained even when a minute force is applied. It needs to be thin or thin. For this reason, there is a problem that damage is likely to occur due to the action of excessive force, and the robustness is lowered.

  In addition, in the case of a force sensor that has the function of detecting each axis component of force and each axis component of moment, it is preferable that the detection sensitivity of each component is balanced in practice. It is difficult for a sensor having a mechanical structure portion to be designed with these balances adjusted.

  Accordingly, an object of the present invention is to provide a force sensor having high detection sensitivity while ensuring sufficient robustness. It is another object of the present invention to provide a force sensor that can easily adjust the balance of detection sensitivity of each axis component of force and moment.

(1) A first aspect of the present invention is a force sensor that detects a force or a moment related to at least one axis among a force in each coordinate axis direction and a moment around each coordinate axis in an XYZ three-dimensional orthogonal coordinate system.
An inner member disposed on the Z-axis of the XYZ three-dimensional orthogonal coordinate system;
An outer member disposed around the Z axis and containing the inner member therein;
It plays the role of connecting the inner member and the outer member, has the property of causing elastic deformation at least in part by the action of the force or moment to be detected, and is arranged so as to partially surround the inner member A plurality of n (n ≧ 2) arc-shaped arms;
A basic structure having
A detecting element for electrically detecting elastic deformation of the arcuate arm;
A detection circuit that outputs a detection value of a force in a predetermined coordinate axis direction acting on the other or a moment around a predetermined coordinate axis in a state where one of the inner member and the outer member is fixed based on a detection result of the detection element;
Provided,
Of the plurality of n arcuate arms, the inner end of the i-th (1 ≦ i ≦ n) arcuate arm is connected to the i-th inner connection point on the inner member, and the outer end is the i-th on the outer member. The first to nth inner connection points are at different positions on the inner member, and the first to nth outer connection points are different positions on the outer member. It is a point that is.

(2) According to a second aspect of the present invention, in the force sensor according to the first aspect described above,
The inner member has a top surface and a bottom surface parallel to the XY plane, and is constituted by a disk-shaped member arranged so that the Z axis is the central axis.
The outer member has an upper surface and a lower surface parallel to the XY plane, and is configured by an annular member arranged so that the Z axis is the central axis.
The disk-shaped member is accommodated in the annular member.

(3) A third aspect of the present invention is the force sensor according to the second aspect described above,
n = 2, the inner member and the outer member are connected by the first arcuate arm and the second arcuate arm,
An XY plane or a predetermined plane parallel to the XY plane is defined as an arrangement plane, and on this arrangement plane, a first inner connection point, a second inner connection point, a first outer connection point, and a second outer connection Points are arranged, and a connecting straight line connecting the first inner connecting point and the second inner connecting point and a connecting straight line connecting the first outer connecting point and the second outer connecting point respectively intersect the Z axis. It is what I did.

(4) According to a fourth aspect of the present invention, in the force sensor according to the third aspect described above,
A first arc-shaped portion in which a first arc-shaped arm extends along an arc centered on the Z axis, and a first inner connecting portion that connects one end of the first arc-shaped portion to a first inner connection point; And a first outer connecting portion that connects the other end of the first arc-shaped portion to the first outer connecting point,
A second arcuate arm extending along an arc centered on the Z axis, and a second inner connecting part for connecting one end of the second arcuate part to the second inner connection point And a second outer connecting portion that connects the other end of the second arc-shaped portion to the second outer connecting point.

(5) According to a fifth aspect of the present invention, in the force sensor according to the third or fourth aspect described above,
The basic structure has a 180 [deg.] Rotationally symmetric structure in which the shape when rotated 180 [deg.] About the Z axis is the same as the shape before the rotation.

(6) A sixth aspect of the present invention is the force sensor according to the second aspect described above,
n = 3 so that the inner member and the outer member are connected by the first arcuate arm, the second arcuate arm, the third arcuate arm,
An XY plane or a predetermined plane parallel to the XY plane is defined as an arrangement plane, and on this arrangement plane, a first inner connection point, a second inner connection point, a third inner connection point, and a first outer connection A point, a second outer connection point, a third outer connection point, a connecting straight line connecting the first inner connection point and the first outer connection point, the second inner connection point and the second outer connection The connecting straight line connecting the points and the connecting straight line connecting the third inner connecting point and the third outer connecting point intersect with the Z axis, respectively.

(7) A seventh aspect of the present invention is the force sensor according to the sixth aspect described above,
A first curved portion in which the first arcuate arm partially surrounds the periphery of the Z-axis; a first inner connection portion that connects one end of the first curved portion to the first inner connection point; A first outer connecting portion for connecting the other end of the curved portion to the first outer connecting point,
A second curved portion in which the second arcuate arm partially surrounds the periphery of the Z-axis; a second inner connection portion that connects one end of the second curved portion to the second inner connection point; A second outer connecting portion that connects the other end of the curved portion to a second outer connecting point,
A third curved portion in which the third arcuate arm partially surrounds the periphery of the Z-axis, a third inner connection portion that connects one end of the third curved portion to the third inner connection point, and a third And a third outer connecting portion for connecting the other end of the curved portion to the third outer connecting point.

(8) According to an eighth aspect of the present invention, in the force sensor according to the sixth or seventh aspect described above,
The basic structure has a 120 [deg.] Rotationally symmetric structure in which the shape when rotated by 120 [deg.] About the Z axis is the same as the shape before the rotation.

(9) A ninth aspect of the present invention is the force sensor according to the second aspect described above,
The inner member and the outer member are connected by a total of n arcuate arms that are first to nth arcuate arms,
The basic structure has a (360 / n) ° rotationally symmetric structure in which the shape when rotated (360 / n) ° about the Z axis is the same as the shape before rotation. is there.

(10) According to a tenth aspect of the present invention, in the force sensor according to the first to ninth aspects described above,
The inner member and the outer member are constituted by rigid bodies that do not substantially deform as long as the applied force or moment is within a predetermined allowable range.

(11) The eleventh aspect of the present invention is the force sensor according to the first to tenth aspects described above,
A support substrate disposed below the basic structure with the Z axis as a vertical axis;
This support substrate has a bottom plate portion that faces the basic structure, and an edge peripheral portion that protrudes upward from the periphery of the bottom plate portion,
The lower surface of the outer member of the basic structure is fixed to the upper surface of the peripheral edge portion, and a cavity is formed between the lower surface of the inner member of the basic structure and the upper surface of the bottom plate portion. It is supported by an arcuate arm so as to be displaceable in the surrounding space including the hollow portion.

(12) The twelfth aspect of the present invention is the force sensor according to the first to tenth aspects described above,
Preparing a plurality of m (m ≧ 2) basic structures arranged so as to be vertically adjacent to each other at a predetermined interval;
When the plurality of m basic structures are called first to mth basic structures from the top to the bottom with the Z axis as the vertical axis, the jth (1 ≦ j ≦ m−1) The lower surface of the inner member of the basic structure and the upper surface of the inner member of the (j + 1) th basic structure are connected, and the lower surface of the outer member of the jth (1 ≦ j ≦ m−1) basic structure and the ( j + 1) is connected to the upper surface of the outer member of the basic structure,
The entire m inner members connected to each other function as a laminated inner member, and the entire m outer members connected to each other function as a laminated outer member;
The detection element electrically detects the elastic deformation of the whole arc-shaped arm of the plurality of m basic structures or a part of the arc-shaped arm selected from the arms, and the detection circuit is based on the detection result of the detection element, In a state in which one of the laminated inner member and the laminated outer member is fixed, a detection value of a force acting on the other coordinate axis direction or a moment around the given coordinate axis is output.

(13) According to a thirteenth aspect of the present invention, in the force sensor according to the twelfth aspect described above,
A support substrate disposed below the m-th basic structure is further provided;
The support substrate has a bottom plate portion facing the m-th basic structure, and an edge peripheral portion that protrudes upward from the periphery of the bottom plate portion,
The lower surface of the outer member of the mth basic structure is fixed to the upper surface of the peripheral edge, and a cavity is formed between the lower surface of the inner member of the mth basic structure and the upper surface of the bottom plate portion. The laminated inner member is supported by an arc arm so as to be displaceable in the surrounding space including the cavity.

(14) According to a fourteenth aspect of the present invention, in the force sensor according to the first to thirteenth aspects described above,
The detecting element detects the elastic deformation of the arcuate arm by electrically detecting the displacement of a predetermined measurement point of the arcuate arm.

(15) According to a fifteenth aspect of the present invention, in the force sensor according to the fourteenth aspect described above,
The detection element is configured to electrically detect the distance between the measurement target surface in the vicinity of a predetermined measurement point of the arc-shaped arm and the opposed reference surface fixed to the inner member or the outer member and facing the measurement target surface. It is.

(16) According to a sixteenth aspect of the present invention, in the force sensor according to the fifteenth aspect described above,
Define the side measurement surface near the measurement point on the inner or outer surface of the arc arm,
It has a side-facing reference plane facing this side-side measurement target surface, and further includes a fixed structure fixed to the inner member or the outer member,
The detection element is configured to electrically detect the distance between the side measurement target surface and the side opposite reference surface.

(17) According to a seventeenth aspect of the present invention, in the force sensor according to the sixteenth aspect described above,
An additional measurement point is further provided at a predetermined position of the inner member or the arc arm, and a lower measurement target surface is defined in the vicinity of the additional measurement point on the lower surface of the inner member or the arc arm,
The detection element is configured to electrically detect the distance between the lower measurement target surface and the lower opposing reference surface that is fixed to the outer member and faces the lower measurement target surface.

(18) According to an eighteenth aspect of the present invention, in the force sensor according to the fifteenth to seventeenth aspects described above,
The detection element is constituted by a capacitive element having a displacement electrode provided on the measurement target surface and a fixed electrode provided on the opposing reference surface.

(19) According to a nineteenth aspect of the present invention, in the force sensor according to the eighteenth aspect described above,
The arc-shaped arm and the inner member are made of a conductive material, and the capacitor element is formed by using the surface of the arc-shaped arm or the inner member as a displacement electrode.

(20) According to a twentieth aspect of the present invention, in the force sensor according to the eighteenth aspect described above,
The capacitive element is configured by forming a displacement electrode on the surface of the arc-shaped arm or the inner member via an insulating layer.

(21) According to a twenty-first aspect of the present invention, in the force sensor according to the first to fifth aspects described above,
n = 2, the inner member and the outer member are connected by the first arcuate arm and the second arcuate arm,
An XY plane or a predetermined plane parallel to the XY plane is defined as an arrangement plane, and on this arrangement plane, a first inner connection point, a second inner connection point, a first outer connection point, and a second outer connection Make sure the points are placed,
The first inner connection point is arranged on or near the projection image of the negative area of the Y axis on the arrangement plane, and the second inner connection point is the projection image of the positive area of the Y axis on the arrangement plane. The first outer connection point is arranged on or near the projection image of the positive region of the Y axis on the arrangement plane, and the second outer connection point is arranged on the arrangement plane. Arranged on or near the projected image of the negative region of the Y axis,
When the rotation direction in which the right screw is advanced in the Z-axis positive direction is defined as a counterclockwise direction and the rotation direction in which the right screw is advanced in the Z-axis negative direction is defined as a clockwise direction, the first arc-shaped arm is connected to the first inner connection. The second arcuate arm extends from the second inner connection point to the second outer connection point, extending from the point toward the first outer connection point in one of the left-handed direction and the right-handed direction. The point extends in the same direction as the selection direction toward the point.

(22) According to a twenty-second aspect of the present invention, in the force sensor according to the twenty-first aspect described above,
Make sure that the centerline of each arcuate arm is on the placement plane,
On the XY plane, a W1 axis obtained by rotating the X axis by 45 ° in the counterclockwise direction and a W2 axis obtained by rotating the Y axis by 45 ° in the counterclockwise direction are defined. A first measurement point is defined at the intersection of the projected image of the region and the center line of the arc arm, and a second measurement is performed at the intersection of the projected image of the negative region of the W1 axis on the placement plane and the center line of the arc arm. A point is defined, a third measurement point is defined at the intersection of the projected image of the positive area of the W2 axis on the placement plane and the center line of the arc arm, and the projected image of the negative area of the W2 axis on the placement plane And when the fourth measurement point is defined at the intersection of the arc arm centerline,
The detection element detects the elastic deformation of each arcuate arm by electrically detecting the displacement of the first to fourth measurement points.

(23) According to a twenty-third aspect of the present invention, in the force sensor according to the twenty-second aspect described above,
A first capacitive element and a second capacitive element arranged in the vicinity of the first measurement point; a third capacitive element and a fourth capacitive element arranged in the vicinity of the second measurement point; A fifth capacitive element and a sixth capacitive element disposed in the vicinity of the third measurement point; and a seventh capacitive element and an eighth capacitive element disposed in the vicinity of the fourth measurement point. And
The first capacitive element is disposed in the vicinity of the first measurement point on the outer side of the arc-shaped arm, and is opposed to the first fixed electrode fixed to the inner member or the outer member, and the first fixed electrode on the surface of the arc-shaped arm. A first displacement electrode formed in the region,
The second capacitive element is disposed in the vicinity of the first measurement point inside the arcuate arm and is opposed to the second fixed electrode fixed to the inner member or the outer member, and the second fixed electrode on the surface of the arcuate arm. A second displacement electrode formed in the region,
The third capacitive element is disposed in the vicinity of the second measurement point on the inner side of the arc-shaped arm, and is opposed to the third fixed electrode fixed to the inner member or the outer member, and the third fixed electrode on the surface of the arc-shaped arm. A third displacement electrode formed in the region,
The fourth capacitive element is disposed in the vicinity of the second measurement point on the outer side of the arc-shaped arm, and is opposed to the fourth fixed electrode fixed to the inner member or the outer member, and the fourth fixed electrode on the surface of the arc-shaped arm. A fourth displacement electrode formed in the region,
The fifth capacitive element is disposed in the vicinity of the third measurement point on the outer side of the arc-shaped arm, and is opposed to the fifth fixed electrode fixed to the inner member or the outer member, and the fifth fixed electrode on the surface of the arc-shaped arm. A fifth displacement electrode formed in the region,
The sixth capacitive element is disposed in the vicinity of the third measurement point on the inner side of the arc-shaped arm and faces the sixth fixed electrode fixed to the inner member or the outer member, and the sixth fixed electrode on the surface of the arc-shaped arm. A sixth displacement electrode formed in the region,
The seventh capacitive element is disposed in the vicinity of the fourth measurement point on the inner side of the arc-shaped arm and faces the seventh fixed electrode fixed to the inner member or the outer member, and the seventh fixed electrode on the surface of the arc-shaped arm. A seventh displacement electrode formed in the region,
The eighth capacitive element is disposed in the vicinity of the fourth measurement point on the outer side of the arc-shaped arm and faces the eighth fixed electrode fixed to the inner member or the outer member, and the eighth fixed electrode on the surface of the arc-shaped arm. And an eighth displacement electrode formed in the region,
In a state where one of the inner member and the outer member is fixed by the detection circuit based on the detection result of the detection element, the force Fx in the X axis direction, the force Fy in the Y axis direction, and the moment Mz around the Z axis are applied to the other member. The detected value is output.

(24) According to a twenty-fourth aspect of the present invention, in the force sensor according to the twenty-third aspect described above,
In addition to the first to fourth measurement points, further, fifth to eighth measurement points are additionally defined at predetermined positions of the arc-shaped arm or the inner member, and the fifth measurement point is placed on the arrangement plane. The sixth measurement point is arranged on the projection image of the positive region of the X axis or in the vicinity thereof, and the sixth measurement point is arranged on the projection image of the negative region of the X axis on the arrangement plane or in the vicinity thereof. The point is arranged on the projection image of the positive area of the Y axis on the arrangement plane or a position near it, and the eighth measurement point is on the projection image of the negative area of the Y axis on the arrangement plane or a position near it. To be placed in
The detection element includes a ninth capacitive element disposed in the vicinity of the fifth measurement point, a tenth capacitive element disposed in the vicinity of the sixth measurement point, and an eleventh element disposed in the vicinity of the seventh measurement point. And a twelfth capacitive element disposed in the vicinity of the eighth measurement point,
When the Z axis is the vertical axis,
The ninth capacitive element includes a ninth fixed electrode disposed in the vicinity of the fifth measurement point below the arc-shaped arm or the inner member and fixed to the outer member, and a ninth fixed electrode on the lower surface of the arc-shaped arm or the inner member. And a ninth displacement electrode formed in a region opposite to
The tenth capacitive element is arranged in the vicinity of the sixth measurement point below the arc-shaped arm or the inner member and fixed to the outer member, and the tenth fixed electrode on the lower surface of the arc-shaped arm or the inner member And a tenth displacement electrode formed in a region opposite to
The eleventh capacitive element includes an eleventh fixed electrode disposed in the vicinity of the seventh measurement point below the arc-shaped arm or the inner member and fixed to the outer member, and an eleventh fixed electrode on the lower surface of the arc-shaped arm or the inner member. And an eleventh displacement electrode formed in a region opposite to
The twelfth capacitive element includes a twelfth fixed electrode disposed in the vicinity of the eighth measurement point below the arcuate arm or the inner member and fixed to the outer member, and a twelfth fixed electrode on the lower surface of the arcuate arm or the inner member. And a twelfth displacement electrode formed in a region opposite to
In a state where one of the inner member and the outer member is fixed by the detection circuit based on the detection result of the detection element, the force Fx in the X-axis direction, the force Fy in the Y-axis direction, and the force Fz in the Z-axis direction applied to the other member The detection values of the moment Mx around the X axis, the moment My around the Y axis, and the moment Mz around the Z axis are output.

(25) According to a twenty-fifth aspect of the present invention, in the force sensor according to the twenty-fourth aspect described above,
Further provided a support substrate disposed below the basic structure,
This support substrate has a bottom plate portion that faces the basic structure, and an edge peripheral portion that protrudes upward from the periphery of the bottom plate portion,
The lower surface of the outer member of the basic structure is fixed to the upper surface of the peripheral edge portion, and a cavity is formed between the lower surface of the inner member of the basic structure and the upper surface of the bottom plate portion. Supported by an arcuate arm so as to be displaceable in the surrounding space including the cavity,
The first to twelfth fixed electrodes are fixed to the upper surface of the bottom plate portion.

(26) According to a twenty-sixth aspect of the present invention, in the force sensor according to the twenty-fourth or twenty-fifth aspect described above,
A first arcuate arm extends counterclockwise from the first inner connection point toward the first outer connection point, and a second arcuate arm extends from the second inner connection point to the second outer connection point. It extends in the counterclockwise direction,
The detection circuit sets the capacitance value of the first capacitance element to C1, the capacitance value of the second capacitance element to C2, the capacitance value of the third capacitance element to C3, and the capacitance value of the fourth capacitance element. The capacitance value is C4, the capacitance value of the fifth capacitance element is C5, the capacitance value of the sixth capacitance element is C6, the capacitance value of the seventh capacitance element is C7, and the eighth capacitance element. The capacitance value of C9, the capacitance value of the ninth capacitance element C9, the capacitance value of the tenth capacitance element C10, the capacitance value of the eleventh capacitance element C11, When the capacitance value of the capacitive element is C12,
Fx = + C1-C2 + C3-C4-C5 + C6-C7 + C8
Fy = + C1-C2 + C3-C4 + C5-C6 + C7-C8
Fz =-(C9 + C10 + C11 + C12)
Mx = −C11 + C12
My = + C9-C10
Mz = + C1-C2-C3 + C4 + C5-C6-C7 + C8
Based on the following formula, the detection of the force Fx in the X-axis direction, the force Fy in the Y-axis direction, the force Fz in the Z-axis direction, the moment Mx around the X-axis, the moment My around the Y-axis, and the moment Mz around the Z-axis A value is output.

(27) According to a twenty-seventh aspect of the present invention, in the force sensor according to the twenty-fourth or twenty-fifth aspect described above,
A first arcuate arm extends clockwise from the first inner connection point toward the first outer connection point, and a second arcuate arm extends from the second inner connection point to the second outer connection point. It extends in the clockwise direction,
The detection circuit sets the capacitance value of the first capacitance element to C1, the capacitance value of the second capacitance element to C2, the capacitance value of the third capacitance element to C3, and the capacitance value of the fourth capacitance element. The capacitance value is C4, the capacitance value of the fifth capacitance element is C5, the capacitance value of the sixth capacitance element is C6, the capacitance value of the seventh capacitance element is C7, and the eighth capacitance element. The capacitance value of C9, the capacitance value of the ninth capacitance element C9, the capacitance value of the tenth capacitance element C10, the capacitance value of the eleventh capacitance element C11, When the capacitance value of the capacitive element is C12,
Fx = + C1-C2 + C3-C4-C5 + C6-C7 + C8
Fy = + C1-C2 + C3-C4 + C5-C6 + C7-C8
Fz =-(C9 + C10 + C11 + C12)
Mx = −C11 + C12
My = + C9-C10
Mz = -C1 + C2 + C3-C4-C5 + C6 + C7-C8
Based on the following formula, the detection of the force Fx in the X-axis direction, the force Fy in the Y-axis direction, the force Fz in the Z-axis direction, the moment Mx around the X-axis, the moment My around the Y-axis, and the moment Mz around the Z-axis A value is output.

(28) According to a twenty-eighth aspect of the present invention, two sets of basic structures constituting the force sensor according to the first to fifth aspects described above are provided.
A detecting element for electrically detecting elastic deformation of the arc-shaped arms of the two sets of basic structures;
Based on the detection result of the detection element, in a state where one of the inner members of the two sets of basic structures and the outer member of the two sets of basic structures is fixed, A detection circuit that outputs a detection value of a moment around a predetermined coordinate axis;
Provided,
The two sets of basic structures are arranged so as to be adjacent in the vertical direction with the Z axis as a vertical axis, and by setting n = 2 in both cases, the inner member and the outer member become the first arc-shaped arm. And a second arcuate arm, and a predetermined plane parallel to the XY plane is defined as an arrangement plane, the first inner connection point and the second inner connection are defined on the arrangement plane. A point, a first outer connection point, a second outer connection point are arranged,
The lower surface of the inner member of the upper basic structure when one of the two sets of basic structures is called the upper basic structure and the other lower one is called the lower basic structure. An inner intermediate member is provided between the upper member and the upper surface of the inner member of the lower basic structure, and between the lower surface of the outer member of the upper basic structure and the upper surface of the outer member of the lower basic structure. An outer intermediate member that connects the two is provided,
The inner member of the upper basic structure, the inner intermediate member, and the inner member of the lower basic structure are connected to each other, and the whole functions as a laminated inner member. The outer member of the upper basic structure, the outer intermediate member, The outer members of the lower basic structure are connected to each other, and the whole functions as a laminated outer member.
The detection element electrically detects elastic deformation of the arc-shaped arms of the upper basic structure and the lower basic structure, and the detection circuit fixes one of the laminated inner member and the laminated outer member based on the detection result of the detection element. In this state, the detection value of the force in the direction of the predetermined coordinate axis acting on the other or the moment around the predetermined coordinate axis is output.

(29) According to a twenty-ninth aspect of the present invention, in the force sensor according to the twenty-eighth aspect described above,
The upper basic structure and the lower basic structure are geometrically congruent structures, both of which are arranged with the Z axis as a common central axis, and the lower basic structure is the upper basic structure Z The shaft is arranged in a direction rotated by 90 ° about the rotation axis.

(30) According to a thirtieth aspect of the present invention, in the force sensor according to the twenty-ninth aspect described above,
As the upper basic structure,
The first inner connection point is arranged on or near the projection image of the negative area of the Y axis on the arrangement plane, and the second inner connection point is the projection image of the positive area of the Y axis on the arrangement plane. The first outer connection point is arranged on or near the projection image of the positive region of the Y axis on the arrangement plane, and the second outer connection point is arranged on the arrangement plane. Arranged on or near the projected image of the negative region of the Y axis,
When the rotation direction in which the right screw is advanced in the Z-axis positive direction is defined as a counterclockwise direction and the rotation direction in which the right screw is advanced in the Z-axis negative direction is defined as a clockwise direction, the first arc-shaped arm is connected to the first inner connection. The second arcuate arm extends from the second inner connection point to the second outer connection point, extending from the point toward the first outer connection point in one of the left-handed direction and the right-handed direction. Using a structure extending in the same direction as the selection direction toward the point,
As the lower basic structure,
A structure in which a structure geometrically congruent with the upper basic structure is arranged in a direction rotated by 90 ° about the Z axis as a rotation axis is used.

(31) According to a thirty-first aspect of the present invention, in the force sensor according to the twenty-eighth aspect described above,
The upper basic structure and the lower basic structure are geometrically congruent structures, both of which are arranged with the Z axis as a common central axis, and the lower basic structure is the upper basic structure X It is arranged so that it is rotated by 180 ° with the axis or Y axis as the rotation axis and further rotated by 90 ° with the Z axis as the rotation axis.

(32) According to a thirty-second aspect of the present invention, in the force sensor according to the thirty-first aspect described above,
As the upper basic structure,
The first inner connection point is arranged on or near the projection image of the negative area of the Y axis on the arrangement plane, and the second inner connection point is the projection image of the positive area of the Y axis on the arrangement plane. The first outer connection point is arranged on or near the projection image of the positive region of the Y axis on the arrangement plane, and the second outer connection point is arranged on the arrangement plane. Arranged on or near the projected image of the negative region of the Y axis,
When the rotation direction in which the right screw is advanced in the Z-axis positive direction is defined as a counterclockwise direction and the rotation direction in which the right screw is advanced in the Z-axis negative direction is defined as a clockwise direction, the first arc-shaped arm is connected to the first inner connection. The second arcuate arm extends from the second inner connection point to the second outer connection point, extending from the point toward the first outer connection point in one of the left-handed direction and the right-handed direction. Using a structure extending in the same direction as the selection direction toward the point,
As the lower basic structure,
A structure in which a structure that is geometrically congruent with the upper basic structure is rotated 180 ° with the X-axis or Y-axis as a rotation axis, and is further rotated 90 ° with the Z-axis as a rotation axis. It is intended to be used.

(33) According to a thirty-third aspect of the present invention, in the force sensor according to the thirtieth or thirty-second aspect described above,
For each of the upper basic structure and the lower basic structure, the center line of each arc-shaped arm is positioned on the arrangement plane,
For the upper basic structure, a first measurement point is defined at the intersection of the projected image of the positive region of the X axis on the placement plane and the center line of the arc arm, and the negative region of the X axis is projected on the placement plane. Define a second measurement point at the intersection of the image and the center line of the arcuate arm,
For the lower basic structure, a third measurement point is defined at the intersection of the projected image of the positive area of the Y axis on the placement plane and the center line of the arcuate arm, and the negative area of the Y axis is projected on the placement plane. Define a fourth measurement point at the intersection of the image and the centerline of the arcuate arm,
The detection element detects the elastic deformation of each arcuate arm by electrically detecting the displacement of the first to fourth measurement points.

(34) According to a thirty-fourth aspect of the present invention, in the force sensor according to the thirty-third aspect described above,
The detection element includes a first capacitive element disposed near the first measurement point, a second capacitive element disposed near the second measurement point, and a third capacitive element disposed near the third measurement point. And a fourth capacitive element disposed in the vicinity of the fourth measurement point,
The first capacitive element is disposed near the first measurement point on the outer side or inner side of the arc-shaped arm and fixed to the laminated inner member or the laminated outer member, and the first fixed on the surface of the arc-shaped arm. A first displacement electrode formed in a region facing the electrode,
The second capacitive element is disposed in the vicinity of the second measurement point outside or inside the arcuate arm and fixed to the laminated inner member or the laminated outer member, and the second fixed electrode on the surface of the arcuate arm. A second displacement electrode formed in a region facing the electrode,
The third capacitor element is disposed near the third measurement point on the outer side or the inner side of the arc-shaped arm and fixed to the laminated inner member or the laminated outer member, and the third fixed electrode on the surface of the arc-shaped arm. A third displacement electrode formed in a region facing the electrode,
The fourth capacitor element is arranged near the fourth measurement point on the outer side or the inner side of the arc-shaped arm, and is fixed to the laminated inner member or the laminated outer member. The fourth fixed element is on the surface of the arc-shaped arm. A fourth displacement electrode formed in a region facing the electrode,
Based on the detection result of the detection element, when the detection circuit fixes one of the laminated inner member and the laminated outer member, the force Fx in the X-axis direction, the force Fy in the Y-axis direction, The detection value of the moment Mz is output.

(35) According to a thirty-fifth aspect of the present invention, in the force sensor according to the thirty-fourth aspect described above,
In addition to the first to fourth measurement points, the fifth to eighth measurement points are defined at predetermined positions of the arc-shaped arm or the inner member of the lower basic structure, and the fifth measurement point is the lower basic structure. The sixth measurement point is located on the projected image of the negative region of the X-axis on the plane of placement of the lower basic structure. Alternatively, the seventh measurement point is arranged on the projection image of the positive region of the Y axis on the arrangement plane of the lower basic structure or in the vicinity thereof, and the eighth measurement point is arranged on the lower stage. It is arranged on the projection image of the negative area of the Y axis on the arrangement plane of the basic structure or in the vicinity thereof,
The detection element includes a fifth capacitive element disposed in the vicinity of the fifth measurement point, a sixth capacitive element disposed in the vicinity of the sixth measurement point, and a seventh capacitive element disposed in the vicinity of the seventh measurement point. And an eighth capacitive element disposed in the vicinity of the eighth measurement point,
The fifth capacitive element includes a fifth fixed electrode disposed in the vicinity of the fifth measurement point below the arc-shaped arm or the inner member of the lower basic structure, and fixed to the outer member of the lower basic structure, and the lower basic structure A fifth displacement electrode formed in a region facing the fifth fixed electrode on the lower surface of the arcuate arm or the inner member of the body,
The sixth capacitive element includes a sixth fixed electrode disposed in the vicinity of the sixth measurement point below the arc-shaped arm or the inner member of the lower basic structure, and fixed to the outer member of the lower basic structure, and the lower basic structure A sixth displacement electrode formed in a region facing the sixth fixed electrode on the arcuate arm of the body or the lower surface of the inner member, and
The seventh capacitive element includes a seventh fixed electrode disposed in the vicinity of the seventh measurement point below the arc-shaped arm or the inner member of the lower basic structure, and fixed to the outer member of the lower basic structure, and the lower basic structure An arcuate arm of the body or a seventh displacement electrode formed in a region facing the seventh fixed electrode on the lower surface of the inner member,
The eighth capacitive element includes an eighth fixed electrode disposed in the vicinity of the eighth measurement point below the arc-shaped arm or inner member of the lower basic structure, and fixed to the outer member of the lower basic structure, and the lower basic structure An arcuate arm of the body or an eighth displacement electrode formed in a region facing the eighth fixed electrode on the lower surface of the inner member,
In a state where one of the laminated inner member and the laminated outer member is fixed based on the detection result of the detection element, the detection circuit acts on the other in the X-axis direction force Fx, the Y-axis direction force Fy, and the Z-axis direction. The detection values of the force Fz, the moment Mx around the X axis, the moment My around the Y axis, and the moment Mz around the Z axis are output.

(36) The thirty-sixth aspect of the present invention is the force sensor according to the thirty-fifth aspect described above,
Further provided a support substrate disposed below the lower basic structure,
The support substrate has a bottom plate portion that faces the lower basic structure, and an edge peripheral portion that protrudes upward from the periphery of the bottom plate portion,
The lower surface of the outer member of the lower basic structure is fixed to the upper surface of the peripheral edge, and a cavity is formed between the lower surface of the inner member of the lower basic structure and the upper surface of the bottom plate, The member is supported by an arcuate arm so as to be displaceable within the surrounding space including the cavity,
The first to eighth fixed electrodes are fixed to the upper surface of the bottom plate portion.

  In the force sensor according to the present invention, the inner member and the outer member are connected by a plurality of n arc-shaped arms having a property of causing elastic deformation at least in part. For this reason, for example, when an external force is applied to the inner member in a state where the outer member is fixed, the arc-shaped arm is elastically deformed and the inner member is displaced. And the external force which acted is detected by detecting the elastic deformation of this arc-shaped arm electrically with a detection element.

  The arc-shaped arm is a member that connects the connection point on the inner member and the connection point on the outer member in an arc shape, and has the property of easily generating elastic deformation by changing the bending state of the arc. Even if it is not made thinner or thinner, sufficient deformation occurs even with a minute external force. For this reason, it becomes possible to provide a force sensor having high detection sensitivity while ensuring sufficient robustness.

  Further, the basic structure constituting the force sensor according to the present invention has a structure in which an outer member is arranged around the inner member and an arc-shaped arm is arranged between the two members. A plurality of m can be stacked vertically. As described above, by adopting a structure in which a plurality of basic structures are stacked one above the other, it becomes possible to easily adjust the balance of detection sensitivity of each axis component of force and moment.

FIG. 2 is a top view (a diagram (a)) of a basic structure 100 of a force sensor according to a basic embodiment of the present invention and a side view (a diagram (b)) of an overall structure in which a support substrate 200 is added thereto. . 2 is a cross-sectional view (FIG. (A)) cut along the XY plane of the entire structure shown in FIG. 1 and a vertical cross-sectional view (FIG. (B)) cut along the XZ plane. It is the longitudinal cross-sectional view which cut | disconnected the whole structure shown in FIG. 1 by the YZ plane. It is a top view of the support substrate 200 shown in FIG. FIG. 3 is a diagram showing a deformation mode when a force + Fx in the X-axis positive direction is applied to the inner member 110 of the basic structure 100 shown in FIG. 2, and FIG. (A) is a cross-sectional view cut along the XY plane, FIG. ) Is a longitudinal sectional view taken along the XZ plane. FIG. 4 is a view showing a deformation mode when a force + Fy in the Y-axis positive direction is applied to the inner member 110 of the basic structure 100 shown in FIG. 2, and FIG. (A) is a cross-sectional view cut along the XY plane, FIG. ) Is a longitudinal sectional view taken along the XZ plane. FIG. 3 is a view showing a deformation mode when a positive force + Fz in the Z-axis is applied to the inner member 110 of the basic structure 100 shown in FIG. 2, and FIG. (A) is a cross-sectional view cut along the XY plane, FIG. ) Is a longitudinal sectional view cut along the XZ plane (the symbol “upper circle” written in the inner member 110 indicates a displacement in the direction perpendicular to the paper surface). FIG. 3 is a diagram showing a deformation mode when a moment + Mx about the positive X axis acts on the inner member 110 of the basic structure 100 shown in FIG. 2, and FIG. (A) is a cross-sectional view cut along the XY plane, FIG. ) Is a vertical cross-sectional view cut along the YZ plane (the symbol “upper circle” and the symbol “lower circle” written in the inner member 110 indicate the displacement in the vertical front direction and the vertical rear direction in the drawing. Is shown). FIG. 3 is a diagram showing a deformation mode when a moment + My around the Y axis acts on the inner member 110 of the basic structure 100 shown in FIG. 2, and FIG. (A) is a cross-sectional view cut along the XY plane, FIG. ) Is a longitudinal cross-sectional view cut along the XZ plane (the “circle-up” and “circle-down” symbols in the inner member 110 indicate the displacement in the vertical front direction and the vertical depth direction of the drawing. Is shown). FIG. 3 is a diagram showing a deformation mode when a moment + Mz around the Z-axis is applied to the inner member 110 of the basic structure 100 shown in FIG. 2, and FIG. (A) is a cross-sectional view cut along the XY plane, FIG. ) Is a longitudinal sectional view taken along the XZ plane. It is a top view which shows the state which has arrange | positioned 12 fixed electrodes E1-E12 on the upper surface of the support substrate 200 shown in FIG. It is a longitudinal cross-sectional view which shows the state which has arrange | positioned 12 fixed electrodes E1-E12 in the whole structure shown in FIG. 2 (the cross section cut | disconnected by the W1-Z plane is shown). 2 is a cross-sectional view showing a force sensor according to a basic embodiment of the present invention configured by arranging twelve fixed electrodes E1 to E12 in the entire structure shown in FIG. 2 (FIG. (A): XY plane) 2 is a cross-sectional view taken along the line X), and a vertical cross-sectional view (FIG. 2B: shows a cross-section cut along the XZ plane). It is a perspective view which shows the size relationship of the counter electrode of each capacitive element used with the force sensor which concerns on basic embodiment shown in FIG. 14 is a table showing changes in capacitance values of the capacitive elements C1 to C12 when a force in each coordinate axis direction and a moment around each coordinate axis are applied to the force sensor according to the basic embodiment shown in FIG. . It is a figure which shows the computing equation which calculates | requires the force of each coordinate axis direction and the moment around each coordinate axis which act with respect to the force sensor which concerns on basic embodiment shown in FIG. It is a figure which shows the detection circuit and detection element which are used for the force sensor which concerns on basic embodiment shown in FIG. FIG. 18 is a circuit diagram showing a detailed configuration of the detection circuit 300 shown in FIG. 17. 13 is a cross-sectional view (FIG. (A): shows a cross section cut along the XY plane) and a vertical cross-sectional view (FIG. (B): cut along the XZ plane) of a force sensor according to a modification of the basic embodiment shown in FIG. Is shown). It is a cross-sectional view (the cross section cut | disconnected by XY plane) of the basic structure 400 which has three arc-shaped arms is shown. The cross-sectional view (FIG. (A): shows a cross section cut along the XY plane) and the side cross-sectional view (FIG. (B)) of the basic structure 100L used for the force sensor according to the two-layered embodiment of the present invention: It shows a cross section cut along the XZ plane). It is a cross-sectional view (the cross section cut | disconnected by the XY plane is shown) of the basic structures 100L and 100R used for the force sensor which concerns on the two-stage laminated type embodiment of this invention. It is a cross-sectional view (the cross section cut | disconnected by XY plane) of basic structure 100LL, 100RR used for the force sensor which concerns on the two-step laminated | stacked embodiment of this invention. 24 is a table showing changes in capacitance values of the capacitive elements C1 to C4 when forces + Fx, + Fy and moment + Mz are applied to the basic structures 100L, 100R, 100LL, and 100RR shown in FIGS. . Each of when force + Fx, + Fy and moment + Mz are applied to a laminated structure in which two sets are selected from the basic structures 100L, 100R, 100LL, and 100RR shown in FIGS. It is a table which shows the change of the electrostatic capacitance value of capacitive element C1-C4. It is a figure which shows the computing equation which calculates | requires the force Fx and Fy which acted with respect to the force sensor using the laminated structure which concerns on the combination of the number 1 shown in FIG. 25, and the number 3 and the moment Mz. In the table of FIG. 25, some “−” columns and some “+” columns are approximately replaced with “0”. It is a figure which shows the computing equation which calculates | requires the force Fx and Fy and the moment Mz which acted with respect to the force sensor using the laminated structure which concerns on each combination of No. 1-No. 4 on the assumption of the table shown in FIG. It is the side view which isolate | separated and showed four components which comprise the laminated structure of the force sensor which concerns on embodiment of the two-stage lamination type of this invention. It is a side view which shows the state which laminated | stacked four structural elements shown in FIG. 29, and comprised the laminated structure. FIG. 31 is a cross-sectional view illustrating a state where the intermediate substrate 500 illustrated in FIG. 30 is cut along an XY plane. FIG. 31 is a longitudinal sectional view showing a state in which the laminated structure shown in FIG. 30 is cut along an XZ plane. It is a top view which shows the state which has arrange | positioned the eight fixed electrodes E1-E8 on the upper surface of the support substrate 200 of the force sensor which concerns on the two-stage laminated type embodiment of this invention. FIG. 33 is a longitudinal sectional view showing a state in which eight fixed electrodes E1 to E8 are arranged in the laminated structure shown in FIG. 32 (shows a section cut along an XZ plane). The cross-sectional view (figure (a)) which shows the state which cut | disconnected the force sensor which concerns on 2 steps | paragraph laminated type embodiment of this invention by the XaYa plane, and the cross-sectional view which shows the state cut | disconnected by the XbYb plane (figure (b) : E5 to E8 indicated by broken circles indicate the positions of the fixed electrodes arranged on the support substrate 200). 36 is a table showing changes in capacitance values of the capacitive elements C1 to C8 when a force in the direction of each coordinate axis and a moment about each coordinate axis are applied to the force sensor having the structure shown in FIG. It is a figure which shows the computing equation which calculates | requires the force of each coordinate axis direction and the moment around each coordinate axis which acted with respect to the force sensor based on the table shown in FIG. 5 is a table showing the detection sensitivity distribution of each axis component for the force sensor according to the basic embodiment of the present invention (one-stage stack) and the force sensor according to the two-layer stack type embodiment (two-stage stack). is there. It is a cross-sectional view (the cross section cut | disconnected by XY plane) of the basic structure which shows the modification of the electrode structure in the force sensor which concerns on this invention is shown.

  Hereinafter, the present invention will be described based on the illustrated embodiments.

<<< §1. Basic structure of force sensor according to the present invention >>
First, the shape of the basic structure that forms the physical structure of the force sensor according to the present invention and the modification thereof will be described with reference to FIGS. As described in detail in Section 2, the force sensor according to the present invention is configured by further adding a detection element and a detection circuit to the basic structure.

  FIG. 1A is a top view of a basic structure 100 of a force sensor according to a basic embodiment of the present invention, and FIG. It is a side view of the whole structure constituted by adding. Here, for convenience of explanation, as shown in the drawing, a point O is taken at the center position of the basic structure 100, and an XYZ three-dimensional orthogonal coordinate system having this point O as the origin is defined.

  Specifically, in FIG. 1 (a), the X-axis is the right side of the figure, the Y-axis is the upper side of the figure, the Z-axis is the coordinate axis toward the front side of the drawing, and in FIG. In the right side of the figure, the Y axis is a vertical direction in the drawing, and the Z axis is a coordinate axis directed upward in the figure. The force sensor according to the present invention has a function of detecting a force or a moment related to at least one axis among forces in the direction of each coordinate axis and moments around each coordinate axis in such an XYZ three-dimensional orthogonal coordinate system.

  As shown in FIG. 1 (a), this basic structure 100 is arranged so as to surround a disk-shaped inner member 110 arranged on the Z-axis of the XYZ three-dimensional orthogonal coordinate system and the Z-axis. An annular (ring-shaped) outer member 120 that houses the member 110 and two arc-shaped arms 130 and 140 that serve to connect the inner member 110 and the outer member 120 are provided.

  As shown in the side view of FIG. 1 (b), the inner member 110 is composed of a disk-shaped member having an upper surface and a lower surface parallel to the XY plane and arranged so that the Z axis is the central axis. Reference numeral 120 denotes an annular member (washer-like member) having an upper surface and a lower surface parallel to the XY plane and arranged so that the Z-axis is a central axis, and the disk-shaped member 110 is an annular member. 120 is housed inside 120.

  Each of the two arc-shaped arms 130 and 140 has a property of causing elastic deformation at least in part by the action of a force or moment to be detected, and is disposed so as to partially surround the inner member 110. ing. Specifically, as shown in FIG. 1 (a), the first arc-shaped arm 130 is disposed so as to surround the right half of the inner member 110, and the second arc-shaped arm 140 includes the inner member 110. It is arrange | positioned so that the semicircle part of the left side of may be enclosed. Note that the term “arc-shaped” in the present application does not necessarily mean an accurate “arc”, but is used to widely include “general curved lines”.

  The inner end of the first arcuate arm 130 is connected to a first inner connection point P1 on the inner member 110, and the outer end is connected to a first outer connection point Q1 on the outer member 120. The inner end of the second arcuate arm 140 is connected to a second inner connection point P2 on the inner member 110, and the outer end is connected to a second outer connection point Q2 on the outer member 120. . Here, the first inner connection point P1 and the second inner connection point P2 are points at different positions on the outer peripheral portion of the disc-shaped inner member 110, and the first outer connection point Q1 and the second inner connection point P2 The connection point Q <b> 2 is a point at a different position on the inner peripheral portion of the annular outer member 120.

  As shown in FIG. 1A, the first arc-shaped arm 130 includes a first arc-shaped portion 131 extending along an arc centered on the Z axis, and one end of the first arc-shaped portion 131 as a first arc. A first inner connecting portion 132 connected to the inner connecting point P1, and a first outer connecting portion 133 connecting the other end of the first arc-shaped portion 131 to the first outer connecting point Q1. Yes. On the other hand, the second arcuate arm 140 connects the second arcuate part 141 extending along an arc centered on the Z axis and one end of the second arcuate part 141 to the second inner connection point P2. It has the 2nd inner side connection part 142, and the 2nd outer side connection part 143 which connects the other end of the 2nd circular arc-shaped part 141 to the 2nd outer side connection point Q2.

  As shown in FIG. 1B, when the Z axis is a vertical axis, a support substrate 200 is disposed below the basic structure 100. In the present application, the term “upper and lower” with respect to the basic structure 100 is used by referring to the Z axis as a vertical axis, the Z axis positive direction as “up”, and the Z axis negative direction as “down”. The support substrate 200 is a disk-shaped substrate having the same outer diameter as that of the basic structure 100, and is arranged with the Z axis as a central axis. The support substrate 200 includes a bottom plate portion 210 that faces the basic structure 100 and an edge peripheral portion 220 that protrudes upward from the periphery of the bottom plate portion 210.

  The structures of the basic structure 100 and the support substrate 200 can be understood more easily by referring to the cross-sectional views of FIGS. 2 and 3 and the top view of FIG. FIG. 2A is a cross-sectional view of the basic structure 100 shown in FIG. 1A cut along the XY plane, and the disk-shaped inner member 110 is placed inside the annular outer member 120. The state of being supported by the second arcuate arm 130 and the second arcuate arm 140 is clearly shown.

  FIG. 2 (b) is a longitudinal sectional view of the entire structure shown in FIG. 1 (b) (with the support substrate 200 added to the basic structure 100) cut along the XZ plane. FIG. It is the longitudinal cross-sectional view cut | disconnected by the plane. As shown in the figure, the lower surface of the outer member 120 of the basic structure 100 is fixed to the upper surface of the edge peripheral portion 220 of the support substrate 200, and the lower surface of the inner member 110 of the basic structure 100 and the upper surface of the bottom plate portion 210 are fixed. A cavity 250 is formed therebetween. The inner member 110 is supported by the two arc-shaped arms 130 and 140 so that the inner member 110 can be displaced in the surrounding space including the cavity 250.

  FIG. 4 is a top view of the support substrate 200. In the case of the embodiment shown here, a cylindrical hollow portion 250 is formed by cutting the center portion of the upper surface of the disk-shaped insulating substrate into a circle, and a process is performed to leave an annular peripheral portion 220 around the hollow portion. ing. A disc-shaped bottom plate portion 210 is formed below the cavity portion 250. The inner member 110 is supported by the two arc-shaped arms 130 and 140 so as to float above the bottom plate portion 210.

  As described above, the two arc-shaped arms 130 and 140 have the property of causing elastic deformation at least partially due to the action of the force or moment to be detected. For this reason, when an external force is applied to the inner member 110 in a state where the support substrate 200 and the outer member 120 connected to the support substrate 200 are fixed, the two arc-shaped arms 130 and 140 are elastically deformed (flexed), The inner member 110 will be displaced. Of course, the same applies when an external force acts on the support substrate 200 and the outer member 120 connected to the support substrate 200 in a state where the inner member 110 is fixed according to the law of action and reaction.

  As described in detail in Section 2, the force sensor according to the present invention is provided with a detection element that electrically detects elastic deformation generated in the arc-shaped arms 130 and 140. Then, a predetermined calculation is performed on the detection result by the detection element by the detection circuit, so that in a state where one of the inner member 110 and the outer member 120 is fixed, a predetermined coordinate axis direction force applied to the other or a predetermined force The detected moment value around the coordinate axis can be output.

  The inner member 110 and the outer member 120 are preferably made of a rigid body that does not substantially deform as long as the applied force or moment is within a predetermined allowable range. If it does so, elastic deformation can be efficiently produced in the arc-shaped arms 130 and 140 by the applied external force, and detection sensitivity can be improved.

  Practically, the entire basic structure 100 is configured as an integral structure made of the same material such as metal or resin, and the arc-shaped arms 130 and 140 are thinned, so that it is sufficient as compared with the inner member 110 and the outer member 120. What is necessary is just to make it have elasticity. For example, if the basic structure 100 is formed by cutting a single metal disk, the machining process can be simplified and the manufacturing cost can be reduced.

  In this case, the inner member 110, the outer member 120, and the arc-shaped arms 130 and 140 are all made of the same metal material, but if the arc-shaped arms 130 and 140 are sufficiently thinned (for detection sensitivity). The thickness of the inner member 110 and the outer member 120 can be made to function as rigid bodies, and the portions of the arc-shaped arms 130 and 140 can be made to function as elastic bodies. .

  The first inner connection point P1, the second inner connection point P2, the first outer connection point Q1, and the second outer connection point Q2 shown in FIG. 1A are all points on the XY plane. In the present application, a plane on which these connection points are arranged is referred to as an arrangement plane. In the case of the basic structure 100 according to the basic embodiment described in §1 and §2, the arrangement plane coincides with the XY plane, but in the case of the two-layered embodiment described in §4, the arrangement plane is an XY plane. Becomes a predetermined plane parallel to.

  In the embodiment shown in FIG. 1 (a), the connecting straight line connecting the first inner connecting point P1 and the second inner connecting point P2 intersects the Z axis (that is, passes through the origin O). The connecting straight line connecting the first outer connection point Q1 and the second outer connection point Q2 also intersects the Z axis (that is, passes through the origin O). In other words, the first inner connection point P1 and the second inner connection point P2 are at opposite positions with respect to the origin O, and the first outer connection point Q1 and the second inner connection point Q2 are It is in the opposite position with respect to the origin O. By adopting such a configuration, the illustrated basic structure 100 has a structure in which the shape when rotated 180 ° about the Z axis as the rotation axis is the same as the shape before rotation (here, “180 ° It is called a “rotationally symmetric structure”.

  Thus, if the basic structure 100 is designed to have a 180 ° rotationally symmetric structure, the elastic deformation that occurs in the arc-shaped arms 130 and 140 when an external force is applied also has a predetermined symmetry with respect to the coordinate axis. Therefore, there can be obtained a merit that simplifies the arithmetic processing necessary for detecting the force in the direction of each coordinate axis and the moment around each coordinate axis. Therefore, in practice, it is preferable to design such a 180 ° rotationally symmetric structure.

  Subsequently, with respect to the basic structure 100 shown in FIG. 2, the elastic deformation of the arc-shaped arms 130 and 140 when a force in the direction of each coordinate axis and a moment about each coordinate axis act on the inner member 110 with the outer member 120 fixed. The aspect of this and the aspect of the inclination of the inner member 110 are demonstrated with reference to FIGS. 5-10 is a figure for demonstrating the characteristic of a deformation | transformation state typically, and does not show an actual deformation | transformation aspect correctly.

  FIG. 5 is a diagram showing a deformation mode when a force + Fx in the X-axis positive direction is applied to the inner member 110 of the basic structure 100 shown in FIG. 2, and the upper diagram (a) is a cross section cut along the XY plane. The front view and the lower part (b) are longitudinal sectional views cut along the XZ plane. When a force + Fx in the positive direction of the X-axis acts on the inner member 110, the inner member 110 moves to the right in the drawing, and the arc-shaped arms 130 and 140 bend accordingly. Specifically, as shown in the figure, the arc-shaped arms 130 and 140 are displaced to the right in the drawing as a whole.

  FIG. 6 is a view showing a deformation mode when a force + Fy in the Y-axis positive direction is applied to the inner member 110 of the basic structure 100 shown in FIG. 2, and the upper drawing (a) is a cross section cut along the XY plane. The front view and the lower part (b) are longitudinal sectional views cut along the XZ plane. When a force + Fy in the Y-axis positive direction acts on the inner member 110, the inner member 110 moves upward in the figure, and the arc-shaped arms 130 and 140 are flexed accordingly. Specifically, as shown in the figure, the arc-shaped arms 130 and 140 are displaced upward in the figure as a whole.

  At this time, the first arcuate arm 130 is subjected to a stress that shortens the entire length, so that the degree of bending increases, resulting in an overall upward displacement in the figure, and the vicinity of the X axis is the right side of the figure. It should be noted that a deformation (see arrow R1) that swells in the direction occurs. On the other hand, the second arcuate arm 140 is subjected to a stress that increases its entire length, so that the degree of bending is reduced, causing an overall upward displacement in the figure, and the portion near the X axis is on the right side of the figure. It should also be noted that deformations (see arrow R2) that deviate to occur occur.

  FIG. 7 is a diagram showing a deformation mode when a force + Fz in the positive direction of the Z-axis is applied to the inner member 110 of the basic structure 100 shown in FIG. 2, and the upper diagram (a) is a cross section cut along the XY plane. The front view and the lower part (b) are longitudinal sectional views cut along the XZ plane. When a force + Fz in the positive direction of the Z-axis acts on the inner member 110, the inner member 110 moves in the direction perpendicular to the plane of the drawing (the symbol “upper circle” written in the inner member 110 is perpendicular to the plane of the drawing). The arc-shaped arms 130 and 140 will bend accordingly. Specifically, as shown in FIG. 7 (b), the inner portions of the arc-shaped arms 130 and 140 are attracted by the upward displacement of the inner member 110 in the drawing, and are displaced upward in the drawing.

  FIG. 8 is a view showing a deformation mode when a moment + Mx about the positive X axis acts on the inner member 110 of the basic structure 100 shown in FIG. 2, and the upper figure (a) is a cross section cut along the XY plane. The front view and the lower part (b) are longitudinal sectional views cut along the YZ plane. 8B is not a cross-sectional view cut along the XZ plane, but a cross-sectional view cut along the YZ plane. In FIG. 8A, the right direction is the X-axis positive direction. In 8 (b), the right direction is the positive Y-axis direction. In the present application, the moment in the rotational direction that advances the right screw in the positive direction of a specific coordinate axis is defined as the positive moment about the specific coordinate axis. Therefore, in the example shown in the figure, the moment + Mx about the positive X axis is a counterclockwise moment in FIG. 8B (the positive direction of the X axis is the direction perpendicular to the paper surface).

  In FIG. 8 (a), the symbols “upper circle” and “lower circle” written in the inner member 110 indicate displacement in the vertical front direction and the vertical rear direction. When a moment + Mx about the positive X-axis acts on the inner member 110, a force is applied to the upper half of the inner member 110 shown in FIG. A force in the direction perpendicular to the paper surface will be applied, and the arc-shaped arms 130 and 140 will bend accordingly.

  FIG. 9 is a diagram showing a deformation mode when a moment + My around the Y axis acts on the inner member 110 of the basic structure 100 shown in FIG. 2, and the upper diagram (a) is a cross section cut along the XY plane. The front view and the lower part (b) are longitudinal sectional views cut along the XZ plane. As shown in FIG. 9 (b), the moment + My about the positive Y-axis is a clockwise moment in the figure.

  In FIG. 9 (a), the symbol “upper circle” and the symbol “lower circle” written in the inner member 110 indicate displacement in the vertical front direction and the vertical rear direction. When a moment + My about the positive Y-axis acts on the inner member 110, a force in the direction perpendicular to the plane of the paper is applied to the left half of the inner member 110 shown in FIG. A force in the direction perpendicular to the paper surface will be applied, and the arc-shaped arms 130 and 140 will bend accordingly.

  FIG. 10 is a diagram showing a deformation mode when a moment + Mz about the positive Z axis acts on the inner member 110 of the basic structure 100 shown in FIG. 2, and the upper diagram (a) is a cross section cut along the XY plane. The front view and the lower part (b) are longitudinal sectional views cut along the XZ plane. As shown in FIG. 10 (a), the positive moment + Mz in the Z-axis direction is a counterclockwise moment in the figure (the positive Z-axis direction is the front direction perpendicular to the paper surface).

  When a moment + Mz about the positive Z-axis acts on the inner member 110, the inner member 110 rotates counterclockwise in FIG. 10A, and the arc-shaped arms 130 and 140 bend accordingly. It will be. Specifically, since stress that reduces the overall length is applied to the first arc-shaped arm 130, the degree of bending increases and deformation that bulges outward occurs. Similarly, since stress that reduces the overall length is applied to the second arc-shaped arm 140, the degree of bending increases and deformation that bulges outward occurs.

  As described above, in the basic structure 100 shown in FIG. 2, when the outer member 120 is fixed, the forces + Fx, + Fy, + Fz and the moments + Mx, + My, + Mz around the respective coordinate axes act on the inner member 110. The mode of elastic deformation of the arc-shaped arms 130 and 140 and the mode of inclination of the inner member 110 have been described. The force sensor according to the basic embodiment of the present invention detects the applied force + Fx, + Fy, + Fz by detecting the elastic deformation of the arc-shaped arms 130 and 140 and the inclination of the inner member 110 by the detection element. And a function of outputting detected values of moments + Mx, + My, + Mz. This function will be described in detail in the next section 2.

<<< §2. Force sensor according to basic embodiment >>
The force sensor according to the basic embodiment of the present invention includes a detection element that electrically detects elastic deformation of the arc-shaped arms 130 and 140 in the basic structure 100 described in §1, and a detection result of the detection element. And a detection circuit for outputting a detection value of a force in a predetermined coordinate axis direction acting on the other member or a moment around a predetermined coordinate axis in a state where one of the inner member 110 and the outer member 120 is fixed. is there.

  As described with reference to FIGS. 5 to 10, the manner of elastic deformation of the arc-shaped arms 130 and 140 when an external force is applied varies depending on the direction of the external force applied, and the degree of elastic deformation depends on the external force applied. Depending on the size of the. Therefore, if the elastic deformation generated in the arc-shaped arms 130 and 140 is electrically detected by the detection element and the detection result is appropriately processed by the detection circuit, the applied force + Fx, + Fy, + Fz and moment + Mx , + My, + Mz detection values can be obtained.

  As one method for electrically detecting the elastic deformation generated in the arcuate arm, a method for detecting the stress generated on the surface of the arcuate arm can be adopted. For example, if a strain gauge is affixed to a predetermined location on the surface of the arc-shaped arm and the gauge resistance of the strain gauge is measured, the stress generated in each part can be detected electrically, and the stress generated in the arc-shaped arm can be detected. It is possible to grasp the mode and size of the elastic deformation.

  However, in the basic embodiment described here, a method of detecting the displacement of a predetermined portion of the arc-shaped arm is adopted. That is, a method for detecting elastic deformation of the arcuate arms 130 and 140 by setting predetermined measurement points on the arcuate arms 130 and 140 and electrically detecting the displacement of the measurement points by a detection element. Yes. Specifically, the distance between the measurement target surface in the vicinity of the measurement point of the arc-shaped arms 130 and 140 and the opposing reference surface that is fixed to the inner member 110 or the outer member 120 and faces the measurement target surface is measured by the detection element. Will be detected automatically.

  As described above, an optical measurement method, a magnetic measurement method, or the like is known as a method for electrically measuring the distance between the measurement target surface that causes the displacement and the fixed counter reference surface. However, the simplest method is a measurement method using the capacitance value of the capacitive element. In other words, if a detection element is configured by a capacitive element having a displacement electrode provided on the measurement target surface and a fixed electrode provided on the opposing reference plane, both are determined based on the capacitance value of the capacitive element. The distance between the electrodes (that is, the distance between the measurement target surface and the opposing reference surface) can be detected. This is because the capacitance value of the capacitive element has a physical property that it is inversely proportional to the distance between both electrodes.

  FIG. 11 is a top view showing a state in which twelve fixed electrodes E1 to E12 are arranged on the upper surface of the support substrate 200 shown in FIG. As described above, the support substrate 200 has a structure in which the annular peripheral portion 220 is provided around the disc-shaped bottom plate portion 210, and the cavity portion 250 is formed therein. The twelve fixed electrodes E1 to E12 are fixed at predetermined positions on the upper surface of the bottom plate portion 210 as shown in the figure. In the case of the embodiment shown here, the support substrate 200 is made of an insulating material, and thus the twelve fixed electrodes E1 to E12 are directly fixed to the upper surface of the bottom plate portion 210. Is made of a conductive material such as a metal, it is necessary to fix the twelve fixed electrodes E1 to E12 to the upper surface of the bottom plate portion 210 through some insulating layer.

  Here, for convenience of describing the arrangement of the fixed electrodes E1 to E8, the W1 axis and the W2 axis are defined as illustrated. These axes are all axes on the XY plane, the W1 axis is an axis obtained by rotating the X axis 45 degrees counterclockwise (counterclockwise in the figure) on the XY plane, and the W2 axis is On the XY plane, this is an axis obtained by rotating the Y axis 45 degrees counterclockwise (counterclockwise in the figure). As shown, the fixed electrodes E1 and E2 are arranged in the positive region of the W1 axis, the fixed electrodes E3 and E4 are arranged in the negative region of the W1 axis, and the fixed electrodes E5 and E6 are arranged in the positive region of the W2 axis. The electrodes E7 and E8 are disposed in the positive region of the W2 axis.

  The fixed electrodes E1 to E8 are electrodes of the same size having a shape obtained by slightly curving a rectangular plate, and the fixed electrodes E1, E4, E5, and E8 are the outer surfaces of the arc-shaped arms 130 and 140 (far from the Z axis). The fixed electrodes E2, E3, E6, E7 are arranged at positions facing the inner side surfaces (surfaces close to the Z axis) of the arc-shaped arms 130, 140. In the case of the embodiment shown here, the fixed electrodes E1, E4, E5, E8 are arranged at positions along a cylindrical surface having a first diameter with the Z axis as the central axis, and the fixed electrodes E2, E3, E6 and E7 are arranged at positions along a cylindrical surface having a second diameter with the Z axis as the central axis. In addition, as the fixed electrodes E1 to E8, a rectangular plate without a curve may be used as it is (the same applies to other embodiments).

  On the other hand, the fixed electrodes E9 to E12 are disk-shaped electrodes of the same size fixed to the upper surface of the bottom plate portion 210. When the X axis and the Y axis are projected on the upper surface of the bottom plate portion 210, the fixed electrode E9 is the X axis. The fixed electrode E10 is arranged on the projected image of the X axis negative region, the fixed electrode E11 is arranged on the projected image of the Y axis positive region, and the fixed electrode E12 is arranged on the Y axis negative region. Are arranged on the projected image. In FIG. 11, a broken-line circle indicates the position of the inner member 110. The fixed electrodes E9 to E12 are all arranged inside the broken circle. This indicates that the fixed electrodes E9 to E12 are arranged at positions facing the lower surface of the inner member 110. In this embodiment, the distance between the center point of each fixed electrode E9 to E12 and the Z axis is set to be the same, and each fixed electrode E9 to E12 is arranged at a position equidistant from the Z axis.

  FIG. 12 is a longitudinal sectional view showing a state in which twelve fixed electrodes E1 to E12 are arranged in the entire structure shown in FIG. This vertical cross-sectional view is a cross-sectional view of the entire structure cut along the W1-Z plane along the W1 axis shown in FIG. 11, so the cross sections of the four fixed electrodes E1 to E4 are shown. (For convenience of illustration, only the cross-sectional portions of the fixed electrodes E1 to E4 are shown).

  12 is a front view of the fixed electrode E6 (the fixed electrode E5 is hidden behind the fixed electrode E6). As described above, each of the eight fixed electrodes E1 to E8 is a rectangular plate-like electrode (for example, a metal plate) like the fixed electrode E6 shown in the figure, and the inner surfaces of the arc-shaped arms 130 and 140 Alternatively, it is arranged at a position facing the outer surface.

  Specifically, the fixed electrode E1 is disposed at a position facing the outer surface of the first arcuate arm 130, and the fixed electrode E2 is disposed at a position facing the inner surface of the first arcuate arm 130 and fixed. The electrode E3 is disposed at a position facing the inner surface of the second arcuate arm 140, and the fixed electrode E4 is disposed at a position facing the outer surface of the second arcuate arm 140.

  In the embodiment shown here, the support substrate 200 is made of an insulating material, but the basic structure 100 is made of a conductive material such as metal. Accordingly, the surface of the first arc-shaped arm 130, the surface of the second arc-shaped arm 140, and the surface of the inner member 110 all function as the displacement electrode E0. For example, the facing portions of the fixed electrodes E1 to E4 on the surfaces of the first arc-shaped arm 130 and the second arc-shaped arm 140 each function as the displacement electrode E0. In the drawing of the present application, for convenience of explanation, these displacement electrodes E0 are indicated by bold lines as necessary.

  In FIG. 12, the thick line drawn on the right side of the first arcuate arm 130 indicates the displacement electrode E0 facing the fixed electrode E1, and the thick line drawn on the left side of the first arcuate arm 130 is the fixed electrode. A displacement electrode E0 is shown opposite to E2. Similarly, the thick line drawn on the right side of the second arcuate arm 140 shows the displacement electrode E0 facing the fixed electrode E3, and the thick line drawn on the left side of the second arcuate arm 140 shows the fixed electrode E4. The displacement electrode E0 which opposes is shown. These displacement electrodes E0 are partial regions on the surfaces of the first arc-shaped arm 130 and the second arc-shaped arm 140 made of a conductive material, and are electrically connected to each other. Therefore, each displacement electrode E0 functions electrically as a single common electrode.

  FIG. 12 is a cross-sectional view of the entire structure cut along the W1-Z plane, but a cross-sectional view cut along the W2-Z plane has the same structure. That is, the partial regions on the surfaces of the first arc-shaped arm 130 and the second arc-shaped arm 140 facing the fixed electrodes E5 to E8 each function as the displacement electrode E0. In FIG. 12, since the fixed electrodes E10 and E11 are electrodes located behind the cut surface, the inner member 110 is drawn with a thick line indicating the displacement electrode E0 facing the fixed electrodes E10 and E11. In actuality, however, the displacement electrode E0 that faces the fixed electrodes E10 and E11 exists in the back portion of the lower surface of the inner member 110 in the drawing.

  FIG. 13A is a cross-sectional view (cross-sectional view cut along the XY plane) showing a state in which twelve fixed electrodes E1 to E12 are arranged in the entire structure shown in FIG. These are the longitudinal cross-sectional views which cut | disconnected this by XZ plane. Also in this figure, the displacement electrode E0 comprised by the opposing part of each fixed electrode E1-E12 of the surface of each arc-shaped arm 130,140 or the inner member 110 is shown by the thick line. In FIG. 13A, the positions of the four fixed electrodes E9 to E12 formed on the support substrate 200 are indicated by broken lines.

  Each drawing of the present application is not a design drawing of the sensor, but a drawing for explaining the principle of the invention. Therefore, the dimensional ratio of each part does not show the dimensional ratio as the actual size. In particular, the thicknesses and positions of the individual electrodes are deformed on the drawing, and are not exactly the same.

  FIG. 13 (a) shows a state in which eight measurement points H1 to H8 are defined at predetermined positions on the XY plane (arrangement plane). Specifically, the first measurement point H1 is defined at the intersection point between the center line of the first arcuate arm 130 (center line extending along the longitudinal direction of the arm) and the positive region of the W1 axis. The measurement point H2 is defined as the intersection position of the center line of the second arcuate arm 140 and the negative region of the W1 axis, and the third measurement point H3 is defined between the centerline of the second arcuate arm 140 and the W2 axis. The fourth measurement point H4 is defined as the intersection position between the center line of the first arcuate arm 130 and the negative area of the W2 axis. Note that the center line of each arc-shaped arm is located on the arrangement plane (XY plane in the embodiment shown here).

  On the other hand, the fifth measurement point H5 is defined on the positive region of the X axis in the inner member 110, and the sixth measurement point H6 is defined on the negative region of the X axis in the inner member 110. The measurement point H7 is defined on the positive region of the Y axis in the inner member 110, and the eighth measurement point H8 is defined on the negative region of the X axis in the inner member 110.

  In the case of the embodiment shown here, the four measurement points H1 to H4 are defined as points on the circumference of the same circle around the origin O on the XY plane, and the four measurement points H5 to H8 are also defined. , Defined as a point on the circumference of the same circle around the origin O on the XY plane. If each measurement point is defined in such a symmetrical position, an arithmetic expression for obtaining a force in each coordinate axis direction and a moment around each coordinate axis is simplified.

  As described above, when the eight measurement points H1 to H8 are used as a reference, first, with respect to the position along the W1 axis, the first measurement point H1 is defined by the fixed electrode E1 and the displacement electrode (thick line portion) facing the fixed electrode E1. The first capacitor C1 is formed near the outside of the first capacitor C1, and the second capacitor is disposed near the inside of the first measurement point H1 by the fixed electrode E2 and the displacement electrode (thick line portion) facing the fixed electrode E2. An element C2 is formed, and a third capacitive element C3 disposed near the inner side of the second measurement point H2 is formed by the fixed electrode E3 and a displacement electrode (bold line portion) facing the fixed electrode E3. The fourth capacitive element C4 disposed near the outside of the second measurement point H2 is formed by the displacement electrode (thick line portion) that faces the center.

  In addition, with respect to the position along the W2 axis, a fifth capacitive element C5 disposed near the outside of the third measurement point H3 is formed by the fixed electrode E5 and the displacement electrode (thick line portion) facing the fixed electrode E5. The fixed electrode E6 and the displacement electrode (thick line portion) opposed thereto form a sixth capacitive element C6 disposed near the inside of the third measurement point H3, and the fixed electrode E7 and the displacement electrode ( The seventh capacitive element C7 disposed near the inner side of the fourth measurement point H4 is formed by the thick line portion), and the fourth measurement point H4 is formed by the fixed electrode E8 and the displacement electrode (thick line portion) opposed thereto. Thus, the eighth capacitive element C8 is formed in the vicinity of the outer side.

  As for the position along the X axis, the ninth capacitive element C9 disposed below the fifth measurement point H5 is formed by the fixed electrode E9 and the displacement electrode (thick line portion) opposed to the fixed electrode E9. The tenth capacitive element C10 disposed below the sixth measurement point H6 is formed by the electrode E10 and the displacement electrode (thick line portion) opposed to the electrode E10. As for the position along the Y-axis, the eleventh capacitive element C11 disposed below the seventh measurement point H7 is formed by the fixed electrode E11 and the displacement electrode facing the fixed electrode E11. Accordingly, a twelfth capacitive element C12 disposed below the eighth measurement point H8 is formed by the displacement electrode opposed to the first electrode.

  Thus, in the case of the embodiment shown here, the inner member 110, the outer member 120, and the arc-shaped arms 130 and 140 are made of a conductive material, so that a part of the surface of the arc-shaped arms 130 and 140 or the inner member 110 is removed. The displacement electrode E0 can be used as opposed to the 12 fixed electrodes E1 to E12, and 12 sets of capacitive elements C1 to C12 can be configured.

  After all, if the side measurement target surface (the bold line portion in FIG. 13 (a)) is defined in the vicinity of the measurement points H1 to H4 on the inner or outer surface of the arc-shaped arms 130 and 140, the eight fixed electrodes E1 to E8 are defined. Has a side-facing reference surface facing this side-side measurement target surface, and functions as a fixed structure fixed to the outer member 120 (actually, each of the fixed electrodes E1 to E8 is supported) The eight capacitive elements C1 to C8 are indirectly fixed to the outer member 120 via the substrate 200), and the detection elements that electrically detect the distance between the side measurement target surface and the side opposite reference surface Will play a role.

  Further, additional measurement points H <b> 5 to H <b> 8 are defined at predetermined locations on the inner member 110. Then, if the lower measurement target surface (thick line portion in FIG. 13 (b)) is defined in the vicinity of the additional measurement points H5 to H8 on the lower surface of the inner member 110, the four fixed electrodes E9 to E12 It has a lower opposed reference surface facing the side measurement target surface, and functions as a fixed structure fixed to the outer member 120 (in practice, each fixed electrode E9 to E12 is interposed via the support substrate 200). The four sets of capacitive elements C9 to C12 serve as detection elements that electrically detect the distance between the lower measurement target surface and the lower opposing reference surface. Will be fulfilled.

  As described above, the capacitive elements C1 to C8 configured by the eight fixed electrodes E1 to E8 and the displacement electrodes facing the fixed electrodes E1 to E8 are in the radial direction of the measurement points H1 to H4 (direction along the W1 axis or W2 axis). However, the detection result is not affected by the displacement of the measurement points H1 to H4 in the vertical direction (Z-axis direction). Similarly, the capacitive elements C9 to C12 constituted by the four fixed electrodes E9 to E12 and the displacement electrodes opposed thereto have a function of detecting displacement in the vertical direction (Z-axis direction) of the measurement points H5 to H8. However, the detection result is not affected by the displacement of the measurement points H5 to H8 in the horizontal direction (direction parallel to the XY plane). The reason is as follows.

  Now, let us consider the capacitance value of a capacitive element composed of a pair of counter electrodes Ea and Eb as shown in FIG. In this example, both the electrodes Ea and Eb are rectangular plate electrodes, but the vertical and horizontal sizes of the electrode Ea are larger than the vertical and horizontal sizes of the electrode Eb. In addition, since both the electrodes Ea and Eb are arranged at positions where their respective center points face each other, a projection image A (orthographic projection image) obtained by projecting the electrode Eb onto the formation surface of the electrode Ea is formed inside the electrode Ea. Is included. In short, the electrode Ea is slightly larger than the electrode Eb.

  In the example shown in FIG. 14, the area inside the projection image A indicated by the broken line is the effective opposing area of this capacitive element. However, both electrodes Ea and Eb are displaced in a direction parallel to the electrode surface. However, as long as the projection image A is included in the electrode Ea, the effective opposing area is constant, so that the capacitance value does not change. Therefore, for example, when the electrode Eb is displaced in the direction perpendicular to the electrode surface, the distance between the electrodes changes and the capacitance value changes, but the electrode Eb is displaced in the direction parallel to the electrode surface. In this case, the distance between the electrodes does not change, and as long as the projection image A is included in the electrode Ea, the effective facing area does not change, so the capacitance value does not change.

  Therefore, the capacitive element shown in FIG. 14 has a function of performing displacement detection in the direction perpendicular to the electrode surface of both electrodes Ea and Eb, but the detection result is the electrode surface of both electrodes Ea and Eb. Is not affected by the displacement in the direction parallel to.

  The capacitive elements C9 to C12 in the force sensor shown in FIG. 13 have the same characteristics. That is, since the size of the displacement electrode E0 (the lower surface of the inner member 110) is larger than the size of the fixed electrodes E9 to E12, the measurement points H5 to H8 are displaced in the horizontal direction (direction parallel to the XY plane). Even if it occurs, the capacitance value does not change as long as the displacement is within a predetermined allowable range (a range in which the effective facing area is kept constant).

  As described above, the projection image obtained by projecting the fixed electrodes E9 to E12 constituting the capacitive elements C9 to C12 onto the formation surface of the opposing displacement electrode E0 (the lower surface of the inner member 110) is included in the displacement electrode E0. It has become a relationship. For this reason, the capacitive elements C9 to C12 have a function of detecting displacement in the vertical direction (Z-axis direction) of the measurement points H5 to H8, but the measurement points H5 to H8 are displaced in the horizontal direction. However, as long as the displacement is within a predetermined allowable range, the displacement in the horizontal direction is not detected by the capacitive elements C9 to C12. In other words, changes in the capacitance values of the capacitive elements C9 to C12 can be handled exclusively as information indicating the vertical displacement (Z-axis direction) of the measurement points H5 to H8.

  Next, consider the capacitive elements C1 to C8. As shown in the cross-sectional view of FIG. 13 (a), the capacitive elements C1 to C8 include the displacement electrodes E0 including the fixed electrodes E1 to E8 and the opposing portions (thick line portions) on the surfaces of the arc-shaped arms 130 and 140. And an element constituted by Here, the fixed electrodes E <b> 1 to E <b> 8 are electrodes extending upward from the upper surface of the bottom plate portion 210 of the support substrate 200 as shown in the longitudinal sectional view of FIG. 12. Actually, the height of the fixed electrodes E <b> 1 to E <b> 8 is set so that the upper end protrudes further above the upper surface of the basic structure 100. Therefore, when the basic structure 100 is bonded to the upper surface of the support substrate 200, the upper ends of the fixed electrodes E1 to E8 protrude from the upper surface of the basic structure 100 by a predetermined amount δ.

  With such a configuration, even if the measurement points H1 to H4 of the arc-shaped arms 130 and 140 are displaced in the vertical direction (Z-axis direction), as long as the displacement amount is within the predetermined amount δ, the fixed electrode There is no change in the effective facing area between E1 to E8 and the counter electrode E0 (thick line portion).

  For example, if the four portions indicated by bold lines in FIG. 12 are grasped as displacement electrodes facing the fixed electrodes E1 to E4, respectively, the projected images of these displacement electrodes projected onto the facing fixed electrodes E1 to E4 are: The relation is included in the fixed electrodes E1 to E4, respectively (the fixed electrodes E1 to E4 are spread vertically). The same applies to the fixed electrodes E5 to E8. For this reason, the capacitive elements C1 to C8 have a function of detecting the displacement in the radial direction of the measurement points H1 to H4, but the measurement points H1 to H4 are displaced in the vertical direction (Z-axis direction). However, as long as the displacement is within a predetermined allowable range, the displacement in the vertical direction is not detected by the capacitive elements C1 to C8. For the same reason, circumferential displacement is not detected. In other words, changes in the capacitance values of the capacitive elements C1 to C8 can be handled exclusively as information indicating the radial displacement of the measurement points H1 to H4.

  15 (a) and 15 (b) show the force in the direction of each coordinate axis with respect to the inner member 110 with the support substrate 200 (outer member 120) of the force sensor shown in FIG. 4 is a table showing changes in capacitance values of the capacitive elements C1 to C12 when a moment around each coordinate axis is applied. In this table, “+” indicates that the capacitance value increases (the distance between both electrodes decreases), and “−” indicates that the capacitance value decreases (the distance between both electrodes increases). “0” indicates that the capacitance value does not vary.

  In addition, the parenthesis written in the “C1 to C12” column of the table indicates a pair of counter electrodes constituting each capacitor element. For example, (E1 & E0) in the C1 column indicates that the capacitive element C1 includes a pair of counter electrodes E1 and E0. Here, the electrode E1 is a fixed electrode, and the electrode E0 (an arc-shaped arm or a partial region of the surface of the inner member) is a displacement electrode.

  As described above, the change in capacitance value of the capacitive elements C1 to C8 exclusively indicates the radial displacement of the measurement points H1 to H4, and the change in capacitance value of the capacitive elements C9 to C12 is exclusively This indicates the displacement in the vertical direction (Z-axis direction) of the measurement points H5 to H8. And the mode of elastic deformation of each arcuate arm 130,140 when the six-axis component of force + Fx, + Fy, + Fz, moment + Mx, + My, + Mz is applied to the inner member 110 is shown in FIGS. As shown. Based on these facts, it can be easily understood that the results shown in the table of FIG. 15 are obtained.

  For example, when a force + Fx is applied, the arc-shaped arms 130 and 140 are elastically deformed as shown in FIG. 5, and are displaced to the right as a whole. For this reason, the measurement points H1 to H4 shown in FIG. 13 (a) are also displaced to the right in the figure and approach the fixed electrodes E1, E8, E6, E3, but move away from the fixed electrodes E2, E7, E5, E4. . For this reason, the capacitance values of the capacitive elements C1, C8, C6, and C3 increase, and the capacitance values of the capacitive elements C2, C7, C5, and C4 decrease. At this time, since the measurement points H1 to H4 are not displaced in the Z-axis direction, the capacitance values of the capacitive elements C9 to C12 do not change. The results in the column “+ Fx” in the tables of FIGS. 15A and 15B are the results obtained based on such a phenomenon.

  On the other hand, when the force + Fy is applied, the arc-shaped arms 130 and 140 are elastically deformed as shown in FIG. 6, and are displaced upward in the figure as a whole. For this reason, the measurement points H1 to H4 shown in FIG. 13 (a) are also displaced upward in the drawing and approach the fixed electrodes E1, E5, E7, and E3, but move away from the fixed electrodes E2, E6, E8, and E4. For this reason, the capacitance values of the capacitive elements C1, C5, C7, and C3 increase, and the capacitance values of the capacitive elements C2, C6, C8, and C4 decrease. At this time, since the measurement points H1 to H4 are not displaced in the Z-axis direction, the capacitance values of the capacitive elements C9 to C12 do not change. The results in the column “+ Fy” in the tables of FIGS. 15A and 15B are the results obtained based on such a phenomenon.

  And when force + Fz acts, each arc-shaped arm 130,140 will produce elastic deformation as shown in FIG. That is, the inner member 110 is displaced in the positive direction of the Z-axis, but the arc-shaped arms 130 and 140 are slightly inclined, but the radial displacement of the measurement points H1 to H4 does not occur. For this reason, the capacitance values of the capacitive elements C1 to C8 do not change. However, since the inner member 110 is displaced in the positive direction of the Z-axis, the electrode interval between the capacitive elements C9 to C12 becomes wide and the capacitance value decreases. The results in the column “+ Fz” in the tables of FIGS. 15A and 15B are the results obtained based on such a phenomenon.

  On the other hand, when the moment + Mx is applied, the arc-shaped arms 130 and 140 are elastically deformed as shown in FIG. That is, the inner member 110 is inclined around the X axis, but the radial displacement of the measurement points H1 to H4 does not occur (strictly speaking, a minute displacement occurs, but this is a substantially negligible amount). . For this reason, the capacitance values of the capacitive elements C1 to C8 do not change. However, since the inner member 110 is inclined around the X axis, the electrode interval of the capacitive element C11 is widened, the capacitance value thereof is decreased, the electrode interval of the capacitive element C12 is reduced, and the capacitance value is increased. To do. At this time, with respect to the capacitive elements C9 and C10, some of the electrode intervals are widened and some of the electrode intervals are narrowed, so that the capacitance value does not change as a whole. The results in the column “+ Mx” in the tables of FIGS. 15A and 15B are obtained based on such a phenomenon.

  Further, when the moment + My is applied, the arc-shaped arms 130 and 140 are elastically deformed as shown in FIG. That is, the inner member 110 is tilted about the Y axis, but no radial displacement occurs at the measurement points H1 to H4 (strictly speaking, a minute displacement occurs, but this is a substantially negligible amount). . For this reason, the capacitance values of the capacitive elements C1 to C8 do not change. However, since the inner member 110 is inclined about the Y axis, the electrode interval of the capacitive element C9 is narrowed, the capacitance value thereof is increased, the electrode interval of the capacitive element C10 is increased, and the capacitance value is decreased. To do. At this time, with respect to the capacitive elements C11 and C12, some of the electrode intervals are widened and some of the electrode intervals are narrowed, so that the capacitance value does not change as a whole. The results in the column “+ My” in the tables of FIGS. 15A and 15B are the results obtained based on such a phenomenon.

  Finally, when the moment + Mz is applied, the arc-shaped arms 130 and 140 undergo elastic deformation as shown in FIG. That is, since each of the arc-shaped arms 130 and 140 swells outward, the measurement points H1 to H4 are displaced outward. Therefore, it approaches the fixed electrodes E1, E4, E5, and E8 arranged on the outer side, but moves away from the fixed electrodes E2, E3, E6, and E7 arranged on the inner side. For this reason, the capacitance values of the capacitive elements C1, C4, C5, and C8 increase, and the capacitance values of the capacitive elements C2, C3, C6, and C7 decrease. At this time, since the measurement points H1 to H4 are not displaced in the Z-axis direction, the capacitance values of the capacitive elements C9 to C12 do not change. The results in the column “+ Mz” in the tables of FIGS. 15A and 15B are obtained based on such a phenomenon.

  As shown in the table of FIG. 15, the six-axis component acts on the change pattern of the capacitance values of the 12 sets of capacitive elements C1 to C12 (here, for convenience, the capacitance values are also indicated by the same reference numerals C1 to C12). The amount of variation in the capacitance value increases as the applied force or moment increases. Therefore, if the detection circuit performs a predetermined calculation based on the measured values of the capacitance values C1 to C12, the detection values of the six-axis components can be output independently.

  FIG. 16 is a diagram showing specific arithmetic expressions for obtaining forces Fx, Fy, Fz in the respective coordinate axes and moments Mx, My, Mz around the respective coordinate axes acting on the force sensor shown in FIG. The reason why each detection value can be obtained by such an arithmetic expression can be understood by referring to the table shown in FIG. For example, referring to the + Fx row in the table of FIG. 15, the sum of C1, C3, C6, and C8 marked with “+” and the sum of C2, C4, C5, and C7 marked with “−” It can be seen that a detected value of + Fx is obtained by the difference between. The same applies to other detection values.

  Further, when negative forces -Fx, -Fy, -Fz and negative moments -Mx, -My, -Mz are applied, "+" and "-" in the table of FIG. 15 are reversed. If the arithmetic expression shown in FIG. 16 is used as it is, each detected value can be obtained as a negative value. The arithmetic expression for the six-axis component shown in FIG. 16 does not receive interference from other axis components, so that each detection value for the six-axis component can be obtained independently. For example, when + Fy acts, C1, C3, C5, and C7 increase and C2, C4, C6, and C8 decrease. However, in the arithmetic expressions for Fx and Mz, these increase and decrease components are canceled each other. Therefore, the Fy component is not included in the detection values for Fx and Mz. Similarly, interference does not occur for the other axial components.

  As shown in FIG. 16, the arithmetic expressions other than the force Fz have a format for obtaining a difference between two sets of capacitance values. In such a difference detection, even if an error occurs in which the basic structure expands or contracts due to a change in the temperature environment and the distance between the counter electrodes fluctuates, the generated error can be canceled mutually. It is preferable for obtaining an accurate detection result that does not contain any. If difference detection is desired for Fz as well, a canopy substrate is provided above the basic structure 100, and a fixed electrode is added to the lower surface of the canopy substrate (for example, in FIG. 11, the XY plane is fixed as a symmetry plane). It is only necessary to form an electrode that is symmetric with the electrodes E9 to E12), and it is sufficient to form a capacitive element that uses the opposing portion of the upper surface of the inner member 110 as a displacement electrode. Since the capacitive element plays a role of measuring the distance between the measurement points H5 to H8 and the lower surface of the canopy substrate, a difference is taken between the capacitance values of these capacitive elements and the capacitance values of the capacitive elements C9 to C12. You can do it.

  FIG. 17 is a diagram showing a detection circuit 300 and detection elements (capacitance elements C1 to C12) used in the force sensor according to the basic embodiment shown in FIG. The detection circuit 300 performs a predetermined calculation process (calculation process based on the calculation formula of FIG. 16) based on the capacitance values of the 12 sets of capacitive elements C1 to C12, thereby obtaining Fx, Fy, Fz, Mx, My, It fulfills the function of outputting a detection value of Mz. In the case of the embodiment described here, the basic structure 100 is made of a conductive material such as a metal. Therefore, one electrode (displacement electrode E0) of each of the capacitive elements C1 to C12 is the same as the basic structure 100. Consists of part of the surface. Therefore, the wiring for the detection circuit 300 need only be one wiring for a predetermined wiring location of the basic structure 100.

  FIG. 18 is a circuit diagram showing a detailed configuration of the detection circuit 300 used in the force sensor shown in FIG. This detection circuit is a circuit that outputs detection values of forces Fx, Fy, Fz and moments Mx, My, Mz as voltage values based on the arithmetic expression shown in FIG. First, the capacitance values C1 to C12 of the 12 sets of capacitive elements C1 to C12 are converted into voltage values V1 to V12 by the C / V converters 301 to 312, respectively. Subsequently, addition / subtraction is performed by the addition / subtraction circuits 321 to 326 based on the arithmetic expressions shown in FIG. 16, and the calculation results are output as detection values of Fx, Fy, Mz, Mx, My, and Fz, respectively.

  Of course, the detection circuit shown in FIG. 18 shows an example, and any circuit may be used as long as the detection result based on the arithmetic expression of FIG. 16 can be output in principle. For example, if a pair of capacitive elements are connected in parallel, the capacitance value of the capacitive element pair after connection is the sum of the capacitance values of the individual capacitive elements. Therefore, in the circuit diagram shown in FIG. If the capacitive elements C1 and C3 are connected in parallel, the capacitance value of the capacitive element pair after the connection is “C1 + C3”, so that the calculation of “V1 + V3” in the addition / subtraction circuit 321 can be omitted.

  FIG. 18 shows a detection circuit using an analog computing unit, but the computation shown in FIG. 16 can of course be performed by digital computation. For example, if an A / D converter is connected to the subsequent stage of the C / V converters 301 to 312, the capacitance values C1 to C12 can be taken in as digital values, respectively. The calculation shown in 16 can be performed, and each detection value can be output as a digital value.

<<< §3. Modification of basic embodiment and basic technical concept >>>
Here, some modifications of the force sensor according to the basic embodiment of the present invention described in Section 2 will be described, and the basic technical concept of the embodiment will be summarized.

<3-1. Modification of Basic Embodiment>
FIG. 19 (a) is a cross-sectional view (cross-sectional view cut along the XY plane) of a force sensor according to a modification of the basic embodiment shown in FIG. 13, and FIG. 19 (b) is an XZ plane. It is a longitudinal cross-sectional view which shows the cross section cut | disconnected by. The only difference from the basic embodiment shown in FIG. 13 is that fixed electrodes E9 ′ to E12 ′ are provided instead of the fixed electrodes E9 to E12. In the case of the basic embodiment shown in FIG. 13, the configuration in which the fixed electrodes E <b> 9 to E <b> 12 are disposed below the inner member 110 on the upper surface of the bottom plate portion 210 of the support substrate 200 has been adopted. In other words, in the case of the basic embodiment shown in FIG. 13, the measurement points H5 to H8 (here, the measurement points H5 to H8 are referred to as additional measurement points in order to be distinguished from the measurement points H1 to H4). Was set at a predetermined location in the inner member 110.

  On the other hand, in the modification shown in FIG. 19, instead of the additional measurement points H5 to H8 in the inner member 110, additional measurement points H5 'to H8' are set in the arc-shaped arms 130 and 140. The fixed electrodes E9 'to E12' are provided below the additional measurement points H5 'to H8'. That is, as shown in FIG. 19 (a), the first measurement point H1 to the fourth measurement point H4 are defined at the same positions as in the basic embodiment shown in FIG. The point H5 ′ is defined as the intersection point between the center line of the arcuate portion 131 of the first arcuate arm 130 and the positive region of the X axis, and the sixth measurement point H6 ′ is a circle of the second arcuate arm 140. It is defined at the intersection position between the center line of the arc-shaped portion 141 and the negative region of the X axis. On the other hand, the seventh measurement point H7 ′ is defined at the position of the outer end of the inner connection 142 of the second arcuate arm 140, and the eighth measurement point H8 ′ is the inner connection of the first arcuate arm 130. 132 is defined at the outer end position.

  The fixed electrodes E9 ′ to E12 ′ are arranged at positions below the additional measurement points H5 ′ to H8 ′ on the upper surface of the bottom plate portion 210 of the support substrate 200. In FIG. 19 (a), the positions of the four fixed electrodes E9 'to E12' are drawn by broken-line circles. Each of these circles is a circle centered on each of the additional measurement points H5 'to H8' on the drawing.

  In FIG. 19B, a disk-shaped fixed electrode E9 'is disposed below the additional measurement point H5', and a disk-shaped fixed electrode E10 'is disposed below the additional measurement point H6'. It is shown. The facing portion (thick line portion) of the fixed electrode E9 ′ on the lower surface of the first arc-shaped arm 130 functions as a displacement electrode, and a ninth capacitive element C9 ′ is formed by a pair of electrodes facing each other. In addition, the facing portion (thick line portion) of the fixed electrode E10 ′ on the lower surface of the second arcuate arm 140 functions as a displacement electrode, and a tenth capacitive element C10 ′ is formed by a pair of electrodes facing each other. Similarly, the eleventh capacitive element C11 ′ is formed by the fixed electrode E11 ′ and the displacement electrode opposed thereto, and the twelfth capacitive element C12 ′ is formed by the fixed electrode E12 ′ and the displacement electrode opposed thereto.

  The functions of the capacitive elements C9 ′ to C12 ′ in the modification shown in FIG. 19 are exactly the same as the functions of the capacitive elements C9 to C12 in the basic embodiment shown in FIG. This is the same as the capacitive elements C9 to C12 shown in FIG. Therefore, the six-axis components Fx, Fy, Fz, Mx, My, and Mz can be independently detected even in the modification using the capacitive elements C9 ′ to C12 ′ instead of the capacitive elements C9 to C12.

  In the case of the modification shown in FIG. 19 (a), the additional measurement points H5 'and H6' are exactly points on the X axis, but the additional measurement points H7 'and H8' are from the Y axis. The point is slightly off. For this reason, for example, the fixed electrode E11 ′ shown in FIG. 19B is arranged at a position slightly shifted to the left from the center. Of course, from the viewpoint of increasing the detection sensitivity as much as possible, the additional measurement points H5 'and H6' are defined as points on the X axis, and the additional measurement points H7 'and H8' are defined as points on the Y axis. Practically, as shown in the example in the figure, if it is a position near each axis, it can be corrected by performing a correction operation even if it is defined at a position slightly off from each axis. Absent.

  The role of the capacitive elements C9 to C12 in the basic embodiment shown in FIG. 13 is to detect the force Fz and the moments Mx and My as shown in the table of FIG. In order to fulfill such a role, the capacitive elements C9 to C12 are not necessarily provided below the inner member 110, but may be provided below the arc-shaped arms 130 and 140. From such a point of view, the modification shown in FIG. 19 uses capacitive elements C9 ′ to C provided below the arc-shaped arms 130 and 140 instead of the capacitive elements C9 to C12 provided below the inner member 110. In this example, C12 ′ is used.

  In the above embodiments, the fixed electrodes E <b> 1 to E <b> 8 are fixed on the bottom plate part 210 of the support substrate 200. Since the support substrate 200 is fixed to the outer member 120, the embodiments so far can be said to be examples in which the fixed electrodes E1 to E8 are fixed to the outer member 120.

  On the other hand, a modification in which the fixed electrodes E1 to E8 are fixed to the inner member 110 is also possible. The arc-shaped arms 130 and 140 are members that connect the inner member 110 and the outer member 120, and when the arc-shaped arms 130 and 140 are elastically deformed, the arc-shaped arms 130 and 140 are also displaced with respect to the inner member 110. It will also be displaced. Therefore, even when the fixed electrodes E1 to E8 are fixed to the inner member 110, the elastic deformation of the arc-shaped arms 130 and 140 can be detected as a change in the capacitance value of the capacitive elements E1 to E8.

  As described above, as shown in FIG. 1, the embodiment in which the basic structure 100 having a specific structure is arranged in a specific direction with respect to the XYZ three-dimensional orthogonal coordinate system has been described. The arrangement is not necessarily limited to the orientation shown in FIG. For example, it is possible to adopt an arrangement in which the basic structure 100 shown in FIG. 1 is rotated 90 ° clockwise or counterclockwise with the Z axis as a rotation axis. In this case, since the X axis and the Y axis are interchanged, and the positive and negative directions of the coordinate axes are interchanged, the change of the capacitance value is slightly different from that shown in the table of FIG.

  It is also possible to employ an arrangement in which the basic structure 100 shown in FIG. 1 is rotated by 180 ° about the X axis or Y axis as a rotation axis. In other words, this is a modified example in which the basic structure 100 is placed upside down. In such a modified example, since the positive and negative directions of the Z axis are reversed, the sign in the “+ Mz” column of the table of FIG. 15A is reversed, and each right side of the Mz expression of FIG. The sign of the term will also be reversed.

  Furthermore, a modification in which the number of arc-shaped arms is three or more is also possible. FIG. 20 is a cross-sectional view (showing a cross section cut along the XY plane) of the basic structure 400 having three arc-shaped arms. The basic structure 400 according to this modification takes a form in which the inner member 410 and the outer member 420 are connected by three arc-shaped arms 430, 440, and 450.

  The inner member 410 is a disk-like member arranged with the Z-axis as the central axis in the same manner as the inner member 110 in the embodiments described so far, and the outer peripheral portion has a first inner connection point as shown in the figure. P1, a second inner connection point P2, and a third inner connection point P3 are defined. On the other hand, the outer member 420 is an annular member arranged with the Z-axis as the central axis in the same manner as the outer member 120 in the embodiments described so far. An outer connection point Q1, a second outer connection point Q2, and a third outer connection point Q3 are defined.

  These connection points P1, P2, P3, Q1, Q2, and Q3 are all points on the XY plane, and the first arc-shaped arm 430 includes the first inner connection point P1 and the first outer connection point Q1. The second arcuate arm 440 connects the second inner connection point P2 and the second outer connection point Q2, and the third arcuate arm 450 connects the third inner connection point P3 and the second inner connection point P3. 3 outer connection points Q3. Of course, these three arc-shaped arms 430, 440, and 450 have a property of causing elastic deformation at least in part by the action of a force or moment to be detected. It is arranged so as to partially surround it.

  The arc-shaped portions 131 and 141 of the first arc-shaped arm 130 and the second arc-shaped arm 140 that constitute the basic structure 100 shown in FIG. 1 are structures that extend along an accurate arc centered on the Z axis. On the other hand, the three arc-shaped arms 430, 440, and 450 constituting the basic structure 400 shown in FIG. 20 are not arcs centered on the Z axis but spiral shapes extending along the vicinity of the arcs. It is comprised by the curved part. As described above, the “arc-shaped arm” used in the present invention does not necessarily need to be an arm along a precise arc, and may be an arm curved so as to partially surround the inner member.

  After all, in the case of the basic structure 400 shown in FIG. 20, the first arcuate arm 430 partially surrounds the periphery of the Z axis, and one end of the first curved portion is connected to the first inner side. A first inner connection portion connected to the connection point P1, and a first outer connection portion connecting the other end of the first bending portion to the first outer connection point Q1, and a second A second curved portion in which the arc-shaped arm 440 partially surrounds the periphery of the Z axis, a second inner connection portion that connects one end of the second curved portion to the second inner connection point P2, and a second A second outer connecting portion that connects the other end of the curved portion to the second outer connecting point Q2, and a third arcuate arm 450 partially surrounds the Z axis. , The third inner connecting portion for connecting one end of the third bending portion to the third inner connection point P3, and the other end of the third bending portion for the third It has a third outer connecting portion connected to an outer connection point Q3, the.

  Of course, the number of arc-shaped arms may be four or more. In general terms, a plurality of n (n ≧ 2) arc-shaped arms that serve to connect the inner member and the outer member are provided, and each arc-shaped arm is at least caused by the action of a force or moment to be detected. It is only necessary to have a property of causing elastic deformation in part and to be disposed so as to partially surround the inner member.

  In addition, in order to stably support the inner member inside the outer member by the plurality of n arcuate arms, the individual inner connection points are different from each other, and the individual outer connection points are also different from each other. To be. That is, among the plurality of n arc-shaped arms, the inner end of the i-th (1 ≦ i ≦ n) arc-shaped arm is connected to the i-th inner connection point on the inner member, and the outer end is on the outer member. It is connected to the i-th outer connection point, and the first to n-th inner connection points are at different positions on the inner member, and the first to n-th outer connection points are different on the outer member. Try to be a point in position.

  In the basic structure 100 shown in FIG. 1A, the inner member 110 and the outer member 120 are connected by the first arc-shaped arm 130 and the second arc-shaped arm 140 by setting n = 2. This is an example. In this example, if the XY plane is defined as an arrangement plane, the first inner connection point P1, the second inner connection point P2, the first outer connection point Q1, and the second outer connection are formed on the arrangement plane. A point Q2 is arranged, and a connecting straight line connecting the first inner connecting point P1 and the second inner connecting point P2 and a connecting straight line connecting the first outer connecting point Q1 and the second outer connecting point Q2 are provided. , Each crossing the Z axis.

  By adopting such a configuration, the basic structure 100 becomes a 180 ° rotationally symmetric structure in which the shape when rotated by 180 ° about the Z axis as the rotation axis is the same as the shape before rotation, and each coordinate axis direction As described above, it is possible to obtain the advantage of simplifying the calculation formula for calculating the force and the moment about each coordinate axis. Further, when a 180 [deg.] Rotationally symmetric structure is employed, the inner member 110 can be supported by the two inner connection points P1 and P2 positioned in the opposite directions, so that a robust structure can be realized. In the case of the two-layered embodiment described in §4, a predetermined plane parallel to the XY plane becomes an arrangement plane instead of the XY plane (this will be described in detail in §4).

  On the other hand, in the basic structure 400 shown in FIG. 20, by setting n = 3, the inner member 410 and the outer member 420 have the first arc-shaped arm 430, the second arc-shaped arm 440, and the third This is an example in which the arc-shaped arms 450 are connected. Also in this example, if the XY plane is defined as an arrangement plane, the first inner connection point P1, the second inner connection point P2, the third inner connection point P3, and the first outer side are arranged on the arrangement plane. A connection point Q1, a second outer connection point Q2, and a third outer connection point Q3 are arranged (in the case of the two-layer stacked embodiment described in §4, parallel to the XY plane instead of the XY plane) The predetermined plane becomes the arrangement plane). A connecting straight line connecting the first inner connecting point P1 and the first outer connecting point Q1, a connecting straight line connecting the second inner connecting point P2 and the second outer connecting point Q2, and a third inner connecting point. The connecting straight line connecting P3 and the third outer connection point Q3 intersects with the Z axis.

  By adopting such a configuration, the basic structure 400 becomes a 120 ° rotationally symmetric structure in which the shape when rotated by 120 ° about the Z-axis as the rotational axis is the same as the shape before the rotation. An arithmetic expression for calculating a force in the coordinate axis direction and a moment around each coordinate axis can be simplified, and a robust support structure for the inner member 110 can be realized.

  Generally speaking, when a configuration in which the inner member and the outer member are connected by a total of n (n ≧ 2) arc-shaped arms, which are first to n-th arc-shaped arms, the basic structure is the Z axis It is only necessary to have a (360 / n) ° rotationally symmetric structure in which the shape when rotated by (360 / n) ° is the same as the shape before rotation.

  Thus, in the basic structure constituting the force sensor according to the present invention, the number n of arc-shaped arms connecting the inner member and the outer member may be an arbitrary number of 2 or more. As described in §1 and §2, n = 2 is set and the inner member 110 and the outer member 120 are connected by the first arc-shaped arm 130 and the second arc-shaped arm 140. Is preferred. This is because, if the inner member 110 is supported at the two inner connection points P1 and P2, a practically robust support structure can be realized and the structure can be simplified. Moreover, as described in §2, if the detection element (capacitance element) is arranged at a specific location, the six-axis components of force and moment can be detected independently.

<3-2. Basic technical concept of basic embodiment>
Here, the basic technical concept of the force sensor according to the basic embodiment described in §2 is summarized. In the present application, for convenience of explanation, a rotation direction in which the right screw is advanced in the Z-axis positive direction is defined as a counterclockwise direction, and a rotation direction in which the right screw is advanced in the Z-axis negative direction is defined as a clockwise direction. For example, in the top view of FIG. 1 (a), the counterclockwise direction is the counterclockwise direction and the clockwise direction is the clockwise direction.

  When such a definition is made, the first arc-shaped arm 130 of the basic structure 100 shown in FIG. 1 (a) is counterclockwise from the first inner connection point P1 toward the first outer connection point Q1. The second arcuate arm 140 extends in the counterclockwise direction from the second inner connection point P2 toward the second outer connection point Q2. In other words, both the first arcuate arm 130 and the second arcuate arm 140 extend in the same counterclockwise direction.

  On the other hand, when the basic structure 100 shown in FIG. 1A is turned upside down by rotating 180 degrees about the X axis or Y axis as the rotation axis, The direction in which the arc-shaped arm extends when viewed from above is the opposite direction. That is, both the first arc-shaped arm 130 and the second arc-shaped arm 140 extend in the clockwise direction.

  As described above, whether the first arc-shaped arm 130 and the second arc-shaped arm 140 are clockwise or counterclockwise is determined by arranging the basic structure 100 face up in the XYZ three-dimensional orthogonal coordinate system, The first arcuate arm 130 and the second arcuate arm 140 extend in the same direction of rotation regardless of the orientation, although this differs depending on whether it is arranged face down. There is no. Of course, it is possible to use a basic structure in which one arc-shaped arm extends clockwise and the other arc-shaped arm extends counterclockwise. However, in practice, both arc-shaped arms have the same rotational direction. It is preferable to employ a structure that extends, since both arc-shaped arms can be efficiently arranged using a narrow space effectively.

  In short, as a general rule, the first arcuate arm 130 is selected from either the left-handed direction or the right-handed direction from the first inner connection point P1 toward the first outer connection point Q2. The second arcuate arm 140 may adopt a structure extending in the same direction as the selection direction from the second inner connection point P2 toward the second outer connection point Q2.

  As shown in FIG. 1 (a), the first inner connection point P1 has an arrangement plane (a plane on which the connection points P1, P2, Q1, and Q2 are arranged, and in the case of the previous embodiments, an XY plane. Although it is itself, in the case of the two-stage stacked embodiment described in §4, it is arranged on the projection image of the negative region of the Y axis on or in the vicinity thereof on a predetermined plane parallel to the XY plane) The second inner connection point P2 is arranged on or near the projection image of the positive region of the Y axis on the arrangement plane, and the first outer connection point Q1 is positive of the Y axis on the arrangement plane. The second outer connection point Q2 is disposed on or near the projected image of the negative region of the Y axis on the placement plane.

  In order to detect the three-axis components such as the force Fx in the X-axis direction, the force Fy in the Y-axis direction, and the moment Mz around the Z-axis using such a basic structure 100, 4 shown in FIG. What is necessary is just to define the measurement points H1-H4 and to detect the displacement electrically.

  Specifically, as shown in FIG. 13A, on the XY plane, the W1 axis obtained by rotating the X axis by 45 ° counterclockwise and the W2 axis obtained by rotating the Y axis by 45 ° counterclockwise. The first measurement point H1 is defined at the intersection of the projected image of the positive area of the W1 axis on the arrangement plane and the center line of the arc-shaped arm 130, and the negative area of the W1 axis on the arrangement plane A second measurement point H2 is defined at the intersection of the projected image of the arc-shaped arm 140 and the center line of the arcuate arm 140, and a third measurement point H3 is defined at the intersection of the projected image of the positive region of the W2 axis on the placement plane Measurement point H3 is defined, a fourth measurement point H4 is defined at the intersection of the projected image of the negative region of the W2 axis on the arrangement plane and the center line of the arc-shaped arm 130, and each measurement point H1 is defined by a detection element. By detecting the displacement of H4 electrically, the elastic deformation of each of the arc-shaped arms 130 and 140 can be detected. Good.

  In the case of the embodiment shown in FIG. 13, eight sets of capacitive elements C1 to C8 are used as detection elements for detecting Fx, Fy, and Mz. That is, the first capacitor element C1 and the second capacitor element C2 arranged in the vicinity of the first measurement point H1, and the third capacitor element C3 and the fourth capacitor arranged in the vicinity of the second measurement point H2. The element C4, the fifth capacitor element C5 and the sixth capacitor element C6 arranged in the vicinity of the third measurement point H3, and the seventh capacitor element C7 and the eighth capacitor element arranged in the vicinity of the fourth measurement point H4. Capacitance element C8.

  Here, the first capacitive element C1 is disposed in the vicinity of the first measurement point H1 outside the arc-shaped arm 130, and is fixed to the outer member 120 (or the inner member 110). A first displacement electrode E0 formed in a region facing the first fixed electrode E1 on the surface of the arc-shaped arm 130, and the second capacitive element C2 is a first measurement inside the arc-shaped arm 130. A second fixed electrode E2 disposed in the vicinity of the point H1 and fixed to the outer member 120 (or the inner member 110), and a second formed on a surface of the arc-shaped arm 130 facing the second fixed electrode E2. And two displacement electrodes E0.

  The third capacitive element C3 includes a third fixed electrode E3 disposed in the vicinity of the second measurement point H2 inside the arc-shaped arm 140 and fixed to the outer member 120 (or the inner member 110), and an arc-shaped element. A third displacement electrode E0 formed in a region facing the third fixed electrode E3 on the surface of the arm 140, and the fourth capacitive element C4 is a second measurement point outside the arc-shaped arm 140. A fourth fixed electrode E4 disposed in the vicinity of H2 and fixed to the outer member 120 (or the inner member 110), and a fourth formed in a region facing the fourth fixed electrode E4 on the surface of the arc-shaped arm 140. Displacement electrode E0.

  The fifth capacitive element C5 includes a fifth fixed electrode E5 disposed in the vicinity of the third measurement point H3 outside the arc-shaped arm 140 and fixed to the outer member 120 (or the inner member 110), and an arc-shaped element. A fifth displacement electrode E0 formed in a region facing the fifth fixed electrode E5 on the surface of the arm 140, and the sixth capacitance element C6 is a third measurement point inside the arc-shaped arm 140. A sixth fixed electrode E6 disposed in the vicinity of H3 and fixed to the outer member 120 (or the inner member 110), and a sixth fixed electrode formed on the surface of the arc-shaped arm 140 facing the sixth fixed electrode E6. Displacement electrode E0.

  Finally, the seventh capacitive element C7 is disposed in the vicinity of the fourth measurement point H4 inside the arc-shaped arm 130 and fixed to the outer member 120 (or the inner member 110), A seventh displacement electrode E0 formed in a region facing the seventh fixed electrode E7 on the surface of the arc-shaped arm 130, and the eighth capacitive element C8 is a fourth measurement outside the arc-shaped arm 130. An eighth fixed electrode E8 disposed in the vicinity of the point H4 and fixed to the outer member 120 (or the inner member 110), and the eighth fixed electrode formed in a region facing the eighth fixed electrode E8 on the surface of the arc-shaped arm 130. 8 displacement electrodes E0.

  Based on the detection results of these detection elements (capacitance elements C1 to C8), the detection circuit 300, in a state in which one of the inner member 110 and the outer member 120 is fixed, the X-axis direction forces Fx and Y-axis acting on the other. The detected values for the three axes of the direction force Fy and the moment Mz around the Z-axis can be output (see equations Fx, Fy, and Mz in FIG. 16).

  On the other hand, in addition to the above three-axis components, a total of six-axis detection values including detection values for the three axes of the force Fz in the Z-axis direction, the moment Mx about the X-axis, and the moment My about the Y-axis are output. Further defines four additional measurement points H5 to H8 (or four additional measurement points H5 ′ to H8 ′ shown in FIG. 19) shown in FIG. What is necessary is just to detect electrically.

  In the embodiment shown in FIG. 13, in addition to the measurement points H <b> 1 to H <b> 4, fifth to eighth measurement points H <b> 5 to H <b> 8 are additionally defined at predetermined locations on the inner member 110. In the embodiment shown in FIG. 19, in addition to the measurement points H1 to H4, fifth to eighth measurement points H5 ′ to H8 ′ are additionally defined at predetermined locations of the arc-shaped arms 130 and 140. ing.

  Here, the fifth measurement points H5 and H5 ′ are arranged on the projection image of the positive region of the X axis on the arrangement plane or in the vicinity thereof, and the sixth measurement points H6 and H6 ′ are on the arrangement plane. The seventh measurement points H7 and H7 'are arranged on the projection image of the positive region of the Y axis on the arrangement plane or in the vicinity thereof. Then, the eighth measurement points H8 and H8 ′ are arranged on the projection image of the negative region of the Y axis on the arrangement plane or in the vicinity thereof.

  As detection elements, ninth capacitive elements C9 and C9 ′ arranged in the vicinity of the fifth measurement points H5 and H5 ′ and tenth capacitive elements arranged in the vicinity of the sixth measurement points H6 and H6 ′. C10, C10 ', the eleventh capacitive elements C11, C11' arranged in the vicinity of the seventh measurement points H7, H7 ', and the twelfth capacitive element arranged in the vicinity of the eighth measurement points H8, H8'. C12 and C12 ′ may be further provided.

  Here, the ninth capacitive elements C9 and C9 ′ are arranged in the vicinity of the fifth measurement points H5 and H5 ′ below the inner member 110 or the arc-shaped arm 130, and are fixed to the outer member 120. , E9 ′ and a ninth displacement electrode E0 formed in a region facing the ninth fixed electrodes E9, E9 ′ on the lower surface of the inner member 110 or the arc-shaped arm 130, and a tenth capacitive element C10 , C10 ′ are arranged in the vicinity of the sixth measurement points H6, H6 ′ below the inner member 110 or the arc-shaped arm 140 and fixed to the outer member 120, and the tenth fixed electrodes E10, E10 ′ and the inner member 110 or And a tenth displacement electrode E0 formed in a region facing the tenth fixed electrodes E10 and E10 ′ on the lower surface of the arc-shaped arm 140.

  Similarly, the eleventh capacitive elements C11 and C11 ′ are arranged in the vicinity of the seventh measurement points H7 and H7 ′ below the inner member 110 or the arc-shaped arm 140, and are eleventh fixed electrodes E11 fixed to the outer member 120. , E11 ′ and an eleventh displacement electrode E0 formed in a region facing the eleventh fixed electrodes E11, E11 ′ on the lower surface of the inner member 110 or the arc-shaped arm 140, and a twelfth capacitive element C12 , C12 ′ are arranged in the vicinity of the eighth measurement points H8, H8 ′ below the inner member 110 or the arc-shaped arm 130 and fixed to the outer member 120, and the inner member 110 or A twelfth displacement electrode E0 formed in a region facing the twelfth fixed electrodes E12 and E12 ′ on the lower surface of the arc-shaped arm 130; It is made.

  Based on the detection results of these detection elements (capacitance elements C1 to C12), the detection circuit 300, in a state in which one of the inner member 110 and the outer member 120 is fixed, the X-axis direction forces Fx and Y-axis acting on the other. The detected values of the direction force Fy, the Z-axis direction force Fz, the X-axis moment Mx, the Y-axis moment My, and the Z-axis moment Mz can be output.

As shown in FIG. 1 (a), the first arcuate arm 130 extends counterclockwise from the first inner connection point P1 toward the first outer connection point Q2, and the second arcuate arm 140 is In the case of using the basic structure 100 that extends in the counterclockwise direction from the second inner connection point P2 toward the second outer connection point Q2, the detection circuit 300, as shown in FIG.
Fx = + C1-C2 + C3-C4-C5 + C6-C7 + C8
Fy = + C1-C2 + C3-C4 + C5-C6 + C7-C8
Fz =-(C9 + C10 + C11 + C12)
Mx = −C11 + C12
My = + C9-C10
Mz = + C1-C2-C3 + C4 + C5-C6-C7 + C8
Based on the following formula, the detection of the force Fx in the X-axis direction, the force Fy in the Y-axis direction, the force Fz in the Z-axis direction, the moment Mx around the X-axis, the moment My around the Y-axis, and the moment Mz around the Z-axis A value can be output.

On the other hand, the first arc-shaped arm 130 extends clockwise from the first inner connection point P1 toward the first outer connection point Q2, and the second arc-shaped arm 140 is the second inner connection point. When a basic structure (a structure in which the basic structure 100 shown in FIG. 1A is turned upside down) extending clockwise from the point P2 toward the second outer connection point Q2 is used, Since the sign of the direction is reversed, the equation of Mz in the above equation is
Mz = -C1 + C2 + C3-C4-C5 + C6 + C7-C8
And reverse.

<<< §4. Two-tiered stack embodiment >>>
Here, a two-layered embodiment using two sets of basic structures will be described.

<4-1. Four variations of basic structure>
FIG. 21 (a) is a cross-sectional view (showing a cross section cut along the XY plane) of the basic structure 100L used in the force sensor according to the two-layer stacked embodiment, and FIG. It is the sectional side view which cut | disconnected this by the XZ plane.

  The basic structure 100L is basically a component that performs the same function as the basic structure 100 shown in FIG. 1, and the difference between the two is that the connection positions of the two arc-shaped arms are slightly different. It is only a point. Therefore, in order to clarify the correspondence between the two, each component of the basic structure 100L shown in FIG. 21 has L at the end of the reference numeral of the corresponding component of the basic structure 100 shown in FIG. The code | symbol which attached | subjected is used.

  Specifically, the basic structure 100L includes an inner member 110L configured by a disk-shaped member disposed with the Z axis as the central axis, and an outer member configured by an annular member disposed with the Z axis as the central axis. 120L, and a first arc-shaped arm portion 130L and a second arc-shaped arm portion 140L that connect both of them.

  If the XY plane is defined as an arrangement plane, the first inner connection point P1, the second inner connection point P2, the first outer connection point Q1, and the second outer connection point Q2 are on the arrangement plane. A connecting straight line connecting the first inner connection point P1 and the second inner connection point P2 (which coincides with the Y-axis in this example) and the first outer connection point Q1 and the second outer connection. The connecting straight lines connecting the points Q2 each intersect the Z axis. Compared with the basic structure 100 shown in FIG. 1, in the basic structure 100L shown in FIG. 21, the first inner connection point P1 and the second inner connection point P2 are arranged on the Y-axis, and the first outer connection The point Q1 and the second outer connection point Q2 are arranged at positions slightly apart from the Y axis.

  The first arcuate arm 130L serves to connect the first inner connection point P1 and the first outer connection point Q1, and the first arcuate part 131L extending along an arc centered on the Z axis. The first arcuate portion 131L has one end connected to the first inner connection point P1 and the other end of the first arcuate portion 131L connected to the first outer connection point Q1. And a first outer connecting portion 133L. Similarly, the second arc-shaped arm 140L serves to connect the second inner connection point P2 and the second outer connection point Q2, and extends along an arc centered on the Z axis. 141L, a second inner connecting portion 142L that connects one end of the second arc-shaped portion 141L to the second inner connecting point P2, and a second outer connecting point that connects the other end of the second arc-shaped portion 141L. And a second outer connecting portion 143L connected to Q2.

  Point G1 is a point on the X-axis positive region, point G2 is a point on the X-axis negative region, point G3 is a point on the Y-axis positive region, and point G4 is a point on the Y-axis negative region. These four points G1 to G4 are called on-axis points. As shown in the drawing, the vicinity of the axial points G1 to G4 is a gap, and a space for arranging the fixed electrode is secured as will be described later. Similarly to the basic embodiment described in §2, the embodiment described in §4 also uses a capacitive element as a detection element that electrically detects the elastic deformation of each arc-shaped arm. The fixed electrodes E1 to E4 arranged in G4 form one electrode of the capacitive element.

  Next, some variations in which the basic structure 100L shown in FIG. 21 is arranged in the XYZ three-dimensional orthogonal coordinate system will be described with reference to FIGS. 22 (a) shows a cross-sectional view of the basic structure 100L, FIG. 22 (b) shows a cross-sectional view of the basic structure 100R, and FIG. 23 (a) shows a basic structure. A cross-sectional view of the body 100LL is shown, and FIG. 23 (b) shows a cross-sectional view of the basic structure 100RR. Each of the drawings shows a cross section of the basic structure cut along the XY plane. In each figure, the orientation of each coordinate axis of the XYZ three-dimensional orthogonal coordinate system is the same, the right side of the figure is the X axis positive direction, the upper side of the figure is the Y axis positive direction, and the front direction perpendicular to the page is the Z axis Become positive.

  The basic structures 100L, 100R, 100LL, and 100RR according to the four variations shown here are physically identical structures. However, since the arrangement manner in the XYZ three-dimensional orthogonal coordinate system is different, different reference numerals are given for convenience. A basic structure 100L shown in FIG. 22 (a) is obtained by arranging the structure shown in FIG. 21 (a) in the same manner as that shown in FIG. 21 (a). On the other hand, the basic structure 100R shown in FIG. 22 (b) is a state in which the structure shown in FIG. 21 (a) is turned upside down (a state rotated by 180 ° about the X axis or Y axis as a rotation axis). It is arranged with.

  As already described, in the present application, for convenience of explanation, the rotation direction in which the right screw is advanced in the Z-axis positive direction is defined as the counterclockwise direction, and the rotation direction in which the right screw is advanced in the Z-axis negative direction is defined as the clockwise direction. Accordingly, the two arc-shaped arms 130L and 140L of the basic structure 100L shown in FIG. 22 (a) both extend counterclockwise from the inside toward the outside. L at the end of the code of the basic structure 100L is an acronym for “Left”. On the other hand, the two arc-shaped arms 130R and 140R of the basic structure 100R shown in FIG. 22B both extend clockwise from the inside toward the outside. R at the end of the code of the basic structure 100R is an acronym “Right”.

  Here, as shown in FIG. 22 (a), a first measurement point H11 is defined at the intersection of the center line of the first arc-shaped arm 130L of the basic structure 100L and the positive region of the X axis, and the basic structure A second measurement point H12 is defined at the intersection of the center line of the 100L second arcuate arm 140L and the negative region of the X axis. Then, the first fixed electrode E1 is arranged near the outside of the first measurement point H11, the second fixed electrode E2 is arranged near the outside of the second measurement point H12, and each of these fixed electrodes E1, E2 and The first capacitive element C1 and the second capacitive element C2 are formed by the displacement electrodes (thick line portions) formed in the opposing regions of the outer surfaces of the arc-shaped arms 130L and 140L.

  Similarly, as shown in FIG. 22 (b), a first measurement point H11 is defined at the intersection of the center line of the first arc-shaped arm 130R of the basic structure 100R and the positive region of the X axis, and the basic structure A second measurement point H12 is defined at the intersection of the center line of the second arcuate arm 140R of 100R and the negative region of the X axis. Then, the first fixed electrode E1 is arranged near the outside of the first measurement point H11, the second fixed electrode E2 is arranged near the outside of the second measurement point H12, and each of these fixed electrodes E1, E2 and The first capacitive element C1 and the second capacitive element C2 are formed by the displacement electrodes (thick line portions) formed in the opposing regions of the outer surfaces of the arc-shaped arms 130R and 140R.

  On the other hand, the basic structure 100LL shown in FIG. 23 (a) is obtained by rotating the basic structure 100L shown in FIG. 22 (a) 90 ° counterclockwise (substantially the same in the clockwise direction). The basic structure 100RR shown in FIG. 23 (b) is obtained by rotating the basic structure 100R shown in FIG. 22 (b) 90 ° counterclockwise (substantially the same in the clockwise direction).

  Here, as shown in FIG. 23 (a), a third measurement point H13 is defined at the intersection of the center line of the first arc-shaped arm 130L of the basic structure 100LL and the positive region of the Y axis, and the basic structure A fourth measurement point H14 is defined at the intersection of the center line of the 100 LL second arcuate arm 140L and the negative region of the Y axis. Then, the third fixed electrode E3 is disposed near the outside of the third measurement point H13, the fourth fixed electrode E4 is disposed near the outside of the fourth measurement point H14, and each of these fixed electrodes E3, E4 and The third capacitive element C3 and the fourth capacitive element C4 are formed by the displacement electrodes (thick line portions) formed in the opposing regions of the outer surfaces of the arc-shaped arms 130L and 140L.

  Similarly, as shown in FIG. 23B, a third measurement point H13 is defined at the intersection of the center line of the first arc-shaped arm 130R of the basic structure 100RR and the positive region of the Y-axis, and the basic structure A fourth measurement point H14 is defined at the intersection of the center line of the second arc-shaped arm 140R of 100RR and the negative region of the Y axis. Then, the third fixed electrode E3 is disposed near the outside of the third measurement point H13, the fourth fixed electrode E4 is disposed near the outside of the fourth measurement point H14, and each of these fixed electrodes E3, E4 and The third capacitive element C3 and the fourth capacitive element C4 are formed by the displacement electrodes (thick line portions) formed in the opposing regions of the outer surfaces of the arc-shaped arms 130R and 140R.

  In the above example, the fixed electrodes E1 to E4 are provided in the vicinity of the outer sides of the measurement points H11 to H14. However, the fixed electrodes E1 to E4 are provided in the vicinity of the inner sides of the measurement points H11 to H14 (each arc shape). It can also be provided inside the arm). However, when the fixed electrodes E1 to E4 are provided on the inner side, it is necessary to consider the positions of the inner connecting portions 132L and 142L so as not to interfere with each other.

  FIG. 24 shows changes in capacitance values of the capacitive elements C1 to C4 when forces + Fx, + Fy and moment + Mz are applied to the basic structures 100L, 100R, 100LL, and 100RR shown in FIGS. It is a table to show. In either case, the outer members 120L and 120R are fixed, and an external force is applied to the inner members 110L and 110R.

  In this table, “+” or “++” indicates that the capacitance value increases (the distance between both electrodes decreases), and “−” or “−−” indicates that the capacitance value decreases ( “0” indicates that the capacitance value does not fluctuate. In addition, “++” indicates that the increase amount is larger than “+”, and “−−” indicates that the decrease amount is larger than “−”.

  As shown in FIG. 13A, the table of FIG. 15A shows eight sets of capacitive elements C1 to C8 configured by eight fixed electrodes E1 to E8 arranged on the W1 axis and the W2 axis. 24 shows the change of the capacitance value, whereas the table of FIG. 24 has four sets of four fixed electrodes E1 to E4 arranged at the axial points G1 to G4 shown in FIG. The change of the electrostatic capacitance value about capacitive element C1-C4 is shown. Therefore, although the contents of the two tables are greatly different, it can be easily understood that the results shown in the table of FIG. 24 are obtained by referring to the modification modes shown in FIGS.

  For example, when a force + Fx is applied to the inner member 110L in the basic structure 100L shown in FIG. 22 (a), the arc-shaped arms 130L and 140L will be elastically deformed as shown in FIG. Displace to the right in the figure. Therefore, the measurement points H11 and H12 shown in FIG. 22 (a) are also displaced to the right in the figure, the measurement point H11 approaches the fixed electrode E1, and the measurement point H12 moves away from the fixed electrode E2. For this reason, the capacitance value of the capacitive element C1 greatly increases to “++”, and the capacitance value of the capacitive element C2 greatly decreases to “−−”.

  On the other hand, when a force + Fy is applied to the inner member 110L in the basic structure 100L shown in FIG. 22 (a), the arc-shaped arms 130L and 140L undergo elastic deformation as shown in FIG. That is, since stress that reduces the overall length is applied to the first arc-shaped arm 130L, the degree of bending increases, and overall, although the displacement in the upward direction in the figure occurs, the portion near the X axis is in the figure. Deformation that slightly swells to the right (see arrow R1) occurs. On the other hand, the second arcuate arm 140L is subjected to a stress that increases its entire length, so that the degree of bending is reduced, and overall, although an upward displacement of the figure occurs, the portion near the X axis is shown in the figure. Deformation (see arrow R2) that slightly deviates to the right occurs. Therefore, the measurement point H11 shown in FIG. 22A is slightly closer to the fixed electrode E1, and the measurement point H12 is slightly away from the fixed electrode E2. For this reason, the capacitance value of the capacitive element C1 slightly increases to “+”, and the capacitance value of the capacitive element C2 slightly decreases to “−”.

  Further, in the basic structure 100L shown in FIG. 22 (a), when a moment + Mz is applied to the inner member 110L, the arc-shaped arms 130L and 140L are elastically deformed as shown in FIG. That is, each arcuate arm 130L, 140L is deformed to swell slightly outward. Therefore, the measurement point H11 shown in FIG. 22 (a) is slightly closer to the fixed electrode E1, and the measurement point H12 is slightly closer to the fixed electrode E2. Therefore, the capacitance value of the capacitive element C1 slightly increases to “+”, and the capacitance value of the capacitive element C2 also increases slightly to “+”.

  The reason why the result of the column “100L” in the table of FIG. 24 has been described above is the same as the reason why the result of the column “100R” is obtained. In the basic structure 100R, the rotation direction in which each arc-shaped arm extends is opposite to that of the basic structure 100L. Therefore, the results when the force + Fy is applied and when the moment + Mz is applied are reversed. In addition, the basic structure 100LL is obtained by rotating the basic structure 100L by 90 °, and the basic structure 100RR is obtained by rotating the basic structure 100R by 90 °. The reason why the result of the “100LL” column can be obtained and the reason why the result of the “100RR” column can be easily understood.

  When force + Fz and moments + Mx and + My are applied, elastic deformation as shown in FIGS. 7 to 9 occurs, but no significant displacement occurs at each measurement point H11 to H14. Therefore, as shown in the column “common” in FIG. 24, the capacitance values C1 to C4 do not change with respect to the effects of + Fz, + Mx, and + My. The table of FIG. 24 shows the increase and decrease of each capacitance value when + Fx, + Fy, and + Mz act. Of course, each electrostatic capacitance when -Fx, -Fy, and -Mz act. The result of increase / decrease in the capacitance value is obtained by reversing the sign shown in this table.

<Combination of 4-2.2 sets of basic structures>
Based on the results shown in the table of FIG. 24, there are four variations of basic structures 100L, 100R, 100LL, and 100RR (as described above, these are physically the same structure, but XYZ three-dimensional orthogonal) By selecting and combining two specific sets from among the arrangement modes in the coordinate system, the three-axis components of forces Fx, Fy and moment Mz can be detected independently. The reason will be described below.

  Generally, there are a total of six combinations for selecting any two items from four types of items. Therefore, there are six combinations for selecting any two sets from the four variations of 100L, 100R, 100LL, and 100RR. However, if there are only four combinations of capacitative elements C1 to C4 that can be used, there are only four types.

  FIG. 25 is a table showing changes in capacitance values of the capacitive elements C1 to C4 when force + Fx, + Fy and moment + Mz are applied to such four combinations. That is, number 1 indicates a combination of basic structures 100L and 100LL, number 2 indicates a combination of basic structures 100L and 100RR, number 3 indicates a combination of basic structures 100R and 100RR, Reference numeral 4 indicates a combination of the basic structures 100R and 100LL. Each of the numbers 1 to 4 is a combination that can use four sets of capacitive elements C1 to C4. In this table, each code column indicating the change in the capacitance value of each of the capacitive elements C1 to C4 is the one in which the content of the corresponding code column in the table of FIG. 24 is fitted.

  Considering the contents of the table shown in FIG. 25, for the combinations of number 1 and number 3, the values of the forces Fx, Fy and moment Mz are obtained independently by performing the calculation using the calculation formula shown in FIG. You can see that

For example, number 1 is a combination of basic structures 100L and 100LL, but as shown in the upper part of FIG.
Fx = (C1 + C4) − (C2 + C3)
Fy = (C1 + C3) − (C2 + C4)
Mz = C1 + C2 + C3 + C4
The detected values of Fx, Fy, and Mz can be obtained by the following arithmetic expression. Here, C1 to C4 are capacitance values of the capacitive elements C1 to C4.

  For example, when only the force + Fx acts, looking at the + Fx code column in the number 1 column of the table of FIG. 25, C1 is “++”, C2 is “−−”, C3 is “−”, and C4 is “−”. Since “+”, it can be seen that the applied force + Fx can be detected by the calculation formula of Fx described above. On the other hand, when only the force + Fy is applied, when the sign column of + Fy is viewed, C1 is “+”, C2 is “−”, C3 is “++”, and C4 is “−−”. The calculation result of the calculation formula is 0. When only the moment + Mz is applied, the + Mz sign field is “+”, so the calculation result of the above-described Fx calculation expression is zero.

  Eventually, the calculation result of the above-described Fx equation becomes a detection value including only the component of the force Fx, and no other axis component is mixed in the detection result. For the same reason, the calculation result of the above Fy arithmetic expression is a detection value including only the component of the force Fy, and the calculation result of the above Mz arithmetic expression is the detection value including only the component of the moment Mz. become. Thus, if the combination is number 1, the values of the forces Fx and Fy and the moment Mz can be detected independently by performing the calculation using the arithmetic expression in the upper part of FIG.

  In the case of the embodiment described here, as described above, since the basic structure has a 180 ° rotationally symmetric structure, the other axis components are canceled out by the calculation using the above-described respective arithmetic expressions. However, if the basic structure does not have symmetry, correction may be made by multiplying each capacitance value by a correction coefficient as appropriate.

On the other hand, number 3 is a combination of the basic structures 100R and 100RR, but as shown in the lower part of FIG.
Fx = (C1 + C3) − (C2 + C4)
Fy = (C2 + C3) − (C1 + C4)
Mz =-(C1 + C2 + C3 + C4)
By performing the calculation using the following equation, the values of the forces Fx and Fy and the moment Mz can be detected independently. The reason can be easily understood by referring to the column of number 3 in the table of FIG.

On the other hand, for the combination of No. 2 and No. 4, independent detection that excludes other axis components cannot be performed. For example, for the combination of number 2,
Fx = (C1 + C3) − (C2 + C4)
When the force Fx is detected by applying the following equation, if only the force + Fx is acting, the code column of + Fx in the column of number 2 in the table of FIG. ", C2 is"-", C3 is" + ", and C4 is"-". Therefore, the value of the force Fx can be obtained by the above-described arithmetic expression. However, when the force + Fy is acting, when the + Fy code column in the number 2 column of the table of FIG. 25 is viewed, C1 is “+”, C2 is “−”, C3 is “++”, and C4 is “ Therefore, it is erroneously detected as the value of the force Fx by the above-described arithmetic expression.

  From the above, two sets of basic structures used in the two-stage stacked embodiment described in §4 are the combination of number 1 (basic structures 100L and 100LL) or the combination of number 3 (basic structure 100R). 100RR) is suitable.

  However, in the case of a force sensor used for an application in which strict detection accuracy is not required, any combination of numbers 1 to 4 may be used. This is because in the table of FIG. 25, it is possible to handle a specific code field in which “+” or “−” is approximated to “0”. Of course, “+” in the table of FIG. 25 indicates that the capacitance value slightly increases, and “−” indicates that the capacitance value decreases slightly. However, the absolute value of the increase amount in the column showing “+” and the absolute value of the decrease amount in the column showing “−” is the absolute value of the increase amount in the column showing “++”. It is smaller than the absolute value of the amount of decrease in the column where “-” is indicated. Therefore, when strict detection accuracy is not required, there is no problem even if “+” or “−” is treated as approximately “0”.

  The table shown in FIG. 27 is based on such a concept, in which some “+” columns and some “−” columns in the table of FIG. 25 are approximately replaced with “0”. Assuming the table shown in FIG. 27, the values of forces Fx, Fy and moment Mz can be detected independently for any combination of numbers 1 to 4. FIG. 28 is a diagram illustrating an arithmetic expression used when performing such detection.

For example, for the combination of number 1 (basic structures 100L and 100LL), assuming the table shown in FIG.
Fx = C1-C2
Fy = C3-C4
Mz = C1 + C2 + C3 + C4
By performing the calculation using the following equation, the values of the forces Fx and Fy and the moment Mz can be detected independently.

For the combination of number 2 (basic structures 100L and 100RR), assuming the table shown in FIG.
Fx = C1-C2
Fy = C3-C4
Mz = C1 + C2-C3-C4
By performing the calculation using the following equation, the values of the forces Fx and Fy and the moment Mz can be detected independently.

On the other hand, for the combination of number 3 (basic structures 100R and 100RR), assuming the table shown in FIG.
Fx = C1-C2
Fy = C3-C4
Mz =-(C1 + C2 + C3 + C4)
By performing the calculation using the following equation, the values of the forces Fx and Fy and the moment Mz can be detected independently.

For the combination of number 4 (basic structures 100R and 100LL), assuming the table shown in FIG.
Fx = C1-C2
Fy = C3-C4
Mz = -C1-C2 + C3 + C4
By performing the calculation using the following equation, the values of the forces Fx and Fy and the moment Mz can be detected independently.

  If the table of FIG. 27 is assumed, the values of the forces Fx, Fy and moment Mz obtained by the respective arithmetic expressions shown in FIG. 28 are correct values without mixing of other axis components. However, as described above, the table in FIG. 27 is originally a column in which “+” or “−” is approximately replaced with “0”, and therefore, actually shown in FIG. The detection value obtained by each arithmetic expression includes an error because the other axis component is mixed.

  As described above, the method for obtaining each detection value by employing the arithmetic expression shown in FIG. 28 is a method for obtaining each detection value by employing the arithmetic expression shown in FIG. 26 (limited to the combination of numbers 1 and 3). Compared to the above, there is a demerit that an error occurs due to mixing of other axis components. However, among the methods for obtaining the respective detection values by employing the arithmetic expression shown in FIG. 28, the combination of numbers 2 and 4 has an advantage that the moment Mz can be differentially detected.

  That is, in the arithmetic expression shown in FIG. 26, the absolute value of the moment Mz is determined by the sum of “C1 + C2 + C3 + C4”, so there is a possibility that noise components such as the temperature and the effect of stress applied during mounting may be mixed. On the other hand, for the combinations of numbers 2 and 4 in FIG. 28, all the arithmetic expressions of Fx, Fy, and Mz include a difference operation, that is, an operation for obtaining a difference between a plurality of capacitance values. The effects of temperature and stress applied at the time of mounting are canceled out, and there is an advantage that noise components can be excluded.

  Therefore, in practical use, it is difficult to accept the former demerit by comparing the demerit of mixing other axis components with the demerit of mixing noise components due to temperature and stress applied during mounting (demerit related to moment Mz detection). In the case of the above, the combination of numbers 1 and 3 is adopted to perform the calculation based on the arithmetic expression of FIG. 26. In the case where the latter disadvantage is difficult to accept, the combination of numbers 2 and 4 is adopted. It suffices to perform an operation based on the equation of FIG.

  Further, the demerit of mixing other axis components can be eliminated by performing a predetermined correction calculation as necessary. Therefore, if the degree of mixing of other axis components is within a range that can be corrected by the correction calculation, the combination of numbers 2 and 4 can be used to perform the calculation and correction calculation based on the calculation formula of FIG. It is also possible to realize a force sensor that eliminates both the disadvantage of mixing other axis components and the disadvantage of mixing noise components due to temperature and stress applied during mounting.

  In addition, the description so far has been based on the premise that mixing the other axis component in the detection value is a demerit that lowers the detection accuracy. However, depending on the application, mixing of the other axis component is a problem. There are cases where this is not possible. For example, in an application for detecting vibration energy of an earthquake, it may be sufficient if only the resultant force in the horizontal direction can be detected. In such a case, there is no need to detect the force Fx and the force Fy separately, so that no trouble occurs even if the detection component of the force Fy is mixed with the detection component of the force Fx. When such a purpose is taken into consideration, usable arithmetic expressions are not limited to the arithmetic expressions shown in FIG. 26 and FIG.

<4-3. Specific Structure of Embodiment with Two-Stage Stacking Type>
Next, a specific structure of the force sensor according to the two-layer stacked embodiment will be described. FIG. 29 is a side view showing four components constituting the laminated structure of the force sensor in isolation. As shown in the figure, this stacked structure is configured by vertically stacking four constituent elements of an upper basic structure 100a, an intermediate substrate 500, a lower basic structure 100b, and a support substrate 200.

  Here, the upper basic structure 100a and the lower basic structure 100b are two sets of basic structures selected from the four basic structures 100L, 100R, 100LL, and 100RR according to FIG. 22 and FIG. is there. Combinations for selecting two sets from the four variations are as shown as numbers 1 to 4 in the tables of FIGS. 25, 27, and 28.

  For example, if the combination of number 1 is adopted, the basic structures 100L and 100LL are selected. Therefore, the basic structure 100L is used as the upper basic structure 100a, and the basic structure 100b is used as the basic structure 100b. A structure 100LL may be used. Alternatively, the basic structure 100LL may be used as the upper basic structure 100a, and the basic structure 100L may be used as the lower basic structure 100b. Here, for convenience, the following description will be given as a representative example in which the basic structure 100L is used as the upper basic structure 100a and the basic structure 100LL is used as the lower basic structure 100b.

  As described in §4-1, the basic structures 100L, 100R, 100LL, and 100RR are physically the same structures, and are different only in the arrangement manner in the XYZ three-dimensional orthogonal coordinate system. . Therefore, the upper basic structure 100a and the lower basic structure 100b shown in FIG. 29 are actually identical structures. In other words, it is enough to prepare two identical parts and change their orientation. For example, when the combination of number 1 is adopted, two basic structures 100L shown in FIG. 22 (a) are prepared as parts, and the first basic structure 100a remains in the orientation shown in FIG. 22 (a). And the second one may be rotated by 90 ° around the Z axis and corrected to the orientation shown in FIG. 23 (a), and arranged as the lower basic structure 100b.

  In the figure showing the embodiment of the two-stage stacked type, for convenience, a lower basic structure is used by using a XaYaZ three-dimensional orthogonal coordinate system having an origin Oa as a coordinate system for explaining the structure of the upper basic structure 100a. An XbYbZ three-dimensional orthogonal coordinate system having an origin Ob is used as a coordinate system for explaining the structure of 100b, and an XYZ three-dimensional orthogonal coordinate system having an origin O is used as a coordinate system for explaining the overall structure of the laminated structure. Will be used. Since the Z axis is the central axis of the stacked structure, the position of the origin is different, but for convenience, it is treated as a common axis in any coordinate system.

  In the case of the representative example described here, since the basic structure 100L is used as the upper basic structure 100a and the basic structure 100LL is used as the lower basic structure 100b, the basic structure 100L is shown in FIG. The origin O, X axis, and Y axis shown are replaced with the origin Oa, Xa axis, and Ya axis, respectively. For the basic structure 100LL, the origin O, X axis, and Y axis shown in FIG. , Xb axis, and Yb axis.

  As shown in FIG. 29, the XaYaZ three-dimensional orthogonal coordinate system for the upper basic structure 100a, the XYZ three-dimensional orthogonal coordinate system for the entire stacked structure, and the XbYbZ three-dimensional orthogonal coordinate system for the lower basic structure 100b are all Since the Z axis is a common axis, the origins Oa, O, and Ob are all located on the common Z axis, and the XaYa plane, the XY plane, and the XbYb plane are parallel to each other.

  FIG. 30 is a side view showing a state where the four structural elements 100a, 500, 100b, and 200 shown in FIG. 29 are laminated to form a laminated structure. Even in this state, the Z axis is a common axis, and the XaYa plane, the XY plane, and the XbYb plane remain unchanged from each other. The origin O of the XYZ three-dimensional orthogonal coordinate system for the entire laminated structure is defined as the center point of the intermediate substrate 500.

  FIG. 31 is a cross-sectional view showing a state in which the intermediate substrate 500 shown in FIG. 30 is cut along the XY plane. As illustrated, the intermediate substrate 500 includes an inner intermediate member 510 and an outer intermediate member 520. The inner intermediate member 510 is a member for connecting the inner members arranged above and below the disk, and is a disk-shaped member having the same size as the inner member. On the other hand, the outer intermediate member 520 is a member for connecting the outer members arranged on the upper and lower sides to each other, and is an annular member having the same size as the outer member. The support substrate 200 is the same structure as the support substrate 200 described in §1, and the top view thereof is as shown in FIG.

  FIG. 32 is a longitudinal sectional view showing a state in which the laminated structure shown in FIG. 30 is cut along the XZ plane. As illustrated, the upper surface of the inner intermediate member 510 is joined to the lower surface of the inner member 110a of the upper basic structure 100a, and the inner member 110b of the lower basic structure 100b (the left and right are connected to the arc-shaped arms 130b and 140b). The lower surface of the inner intermediate member 510 is joined to the upper surface. Further, the upper surface of the outer intermediate member 520 is bonded to the lower surface of the outer member 120a of the upper basic structure 100a, and the lower surface of the outer intermediate member 520 is bonded to the upper surface of the outer member 120b of the lower basic structure 100b. The lower surface of the outer member 120 b of the lower basic structure 100 b is bonded to the upper surface of the edge peripheral portion 220 of the support substrate 200. Therefore, a cavity 250 is formed between the lower surface of the inner member 110b of the lower basic structure 100b and the upper surface of the bottom plate 210.

  After all, in the laminated structure shown in FIG. 32, the inner member 110a, the inner intermediate member 510 of the upper basic structure 100a, and the inner member 110b of the lower basic structure 100b are joined together in a state where three layers are laminated in the vertical direction. The whole functions as a laminated inner member. Similarly, the outer member 120a, the outer intermediate member 520 of the upper basic structure 100a, and the outer member 120b of the lower basic structure 100b are joined together in a state where three layers are laminated in the vertical direction, and the whole functions as a laminated outer member. It will be. This laminated outer member is bonded to the support substrate 200.

  On the other hand, the arc-shaped arms 130a and 140a of the upper basic structure 100a and the arc-shaped arms 130b and 140b of the lower basic structure 100b function as separate and independent arms. Therefore, the laminated inner member and the laminated outer member are connected by the four arc-shaped arms 130a, 140a, 130b, and 140b having the property of causing elastic deformation at least in part. As shown in FIG. 32, a surrounding space including the cavity portion 250 is formed between the laminated inner member and the laminated outer member. When the laminated inner member is subjected to the action of an external force, the surrounding space is formed. Can be displaced within.

  When the laminated inner member subjected to the action of the external force is displaced, the four arc-shaped arms 130a, 140a, 130b, 140b are elastically deformed. Therefore, the basic embodiment described so far is that a detection element for electrically detecting this elastic deformation is provided, and the force or moment acting as an external force is obtained based on the detection result of this detection element. It is the same. Hereinafter, an embodiment using a capacitive element as the detection element will be described.

  FIG. 33 is a top view showing a state in which eight fixed electrodes E1 to E8 are arranged on the upper surface of the support substrate 200 of the force sensor according to the two-stage stacked embodiment. In the case of the embodiment described in §2, as shown in FIG. 11, a total of 12 fixed electrodes E1 to E12 are provided on the support substrate 200. In the case of the two-stage stacked embodiment described here, As shown in FIG. 33, it is sufficient to provide a total of eight fixed electrodes E1 to E8 on the support substrate 200.

  First, the fixed electrodes E5 to E8 shown in FIG. 33 are disk-shaped electrodes corresponding to the fixed electrodes E9 to E12 shown in FIG. 11, and the shape and arrangement are exactly the same as those of the fixed electrodes E9 to E12 shown in FIG. . That is, when the X axis and the Y axis are projected onto the upper surface of the bottom plate portion 210, the fixed electrode E5 is disposed on the projected image of the X axis positive region, and the fixed electrode E6 is disposed on the projected image of the X axis negative region, The fixed electrode E7 is disposed on the projected image of the Y-axis positive area, and the fixed electrode E8 is disposed on the projected image of the Y-axis negative area.

  A circle indicated by a broken line in the drawing indicates a position of the inner member 110b of the lower basic structure 100b, and the fixed electrodes E5 to E8 are all disposed within the broken circle. This indicates that the fixed electrodes E5 to E8 are disposed at positions facing the lower surface of the inner member 110b. In this embodiment, the distance between the center point of each of the fixed electrodes E5 to E8 and the Z axis is set to be the same, and each of the fixed electrodes E5 to E8 is arranged at an equal distance from the Z axis.

  On the other hand, the fixed electrodes E1 to E4 shown in FIG. 33 are electrodes arranged on the outer side of each arc-like arm similarly to the fixed electrodes E1, E4, E5, and E8 shown in FIG. It is the electrode of the same size which made the shape made. However, the fixed electrodes E1, E4, E5, and E8 shown in FIG. 11 are arranged on the W1 axis or the W2 axis, whereas the fixed electrodes E1 to E4 shown in FIG. 33 are on the X axis or the Y axis. (To be precise, the projection image on the XY plane is arranged at a position on the X axis or the Y axis). Also, the fixed electrodes E1 to E4 shown in FIG. 33 are supported by support members S1 to S4 of the same size having a shape obtained by slightly curving a rectangular plate.

  Here, the support members S1 to S4 are insulating structures fixed to the upper surface of the bottom plate portion 210 so as to extend upward, and the upper ends thereof are further upward from the upper surface of the upper basic structure 100a. It sticks out. As shown in FIG. 33, the specific arrangement of the support members S1 to S4 is as follows. The support member S1 is the X-axis positive region, the support member S2 is the X-axis negative region, the support member S3 is the Y-axis positive region, and the support member. S4 is the Y-axis negative region. In the case of the embodiment shown here, the support members S1 to S4 are arranged at positions along a cylindrical surface (the surface of the cylinder containing each arc-shaped arm) with the Z axis as the central axis.

  On the other hand, the fixed electrodes E1 to E4 are electrodes supported by the support members S1 to S4, respectively, but the vertical dimension thereof is set shorter than the vertical dimension of the support members S1 to S4. In other words, the fixed electrodes E1 and E2 are formed at necessary and sufficient positions as electrodes facing the side surfaces of the arc-shaped arms 130a and 140a of the upper basic structure 100a, and the fixed electrodes E3 and E4 are formed as the lower basic structure 100b. Are formed at necessary and sufficient positions as electrodes facing the side surfaces of the arc-shaped arms 130b and 140b. This is clearly shown in FIG.

  FIG. 34 is a longitudinal sectional view showing a state in which eight fixed electrodes E1 to E8 are arranged in the laminated structure shown in FIG. 32, and shows a section cut along the XZ plane. As described above, the stacked structure is a structure in which four constituent elements 100a, 500, 100b, and 200 are stacked one above the other.

  A state in which the fixed electrode E1 is arranged near the upper part of the support member S1 is shown near the right end of the figure, and a state in which the fixed electrode E2 is arranged near the upper part of the support member S2 near the left end of the figure. It is shown. The fixed electrode E1 is disposed at a position facing the outer surface of the arc-shaped arm 130a of the upper basic structure 100a, and the facing surface (thick line portion) of the surface of the arc-shaped arm 130a is a displacement electrode E0 facing the fixed electrode E1. Function as. Similarly, the fixed electrode E2 is disposed at a position facing the outer surface of the arc-shaped arm 140a of the upper basic structure 100a, and the facing surface (thick line portion) of the surface of the arc-shaped arm 140a faces the fixed electrode E2. It functions as the displacement electrode E0.

  Here, the relationship between the fixed electrode E1 and the displacement electrode E0 (thick line portion) opposed thereto and the relationship between the fixed electrode E2 and the displacement electrode E0 (thick line portion) opposed thereto are the relationships described in FIG. ing.

  A support member S3 is drawn at the back of the center of FIG. The support member S3 is a member that supports the fixed electrode E3. The fixed electrode E3 is disposed at a position facing the outer surface of the arc-shaped arm 130b (an arm located at the back of the inner member 110b) of the lower basic structure 100b, and a part of the fixed electrode E3 is located below the inner member 110b in the drawing. Is shown in a peeping state. Although not shown in FIG. 34, a support member S4 for supporting the fixed electrode E4 is disposed on the front side of the inner member 110b. Here, the fixed electrode E4 is disposed at a position facing the outer surface of the arc-shaped arm 140b (an arm positioned in front of the inner member 110b) of the lower basic structure 100b.

  The portion facing the fixed electrode E3 on the surface of the arc-shaped arm 130b functions as the displacement electrode E0, and the portion facing the fixed electrode E4 on the surface of the arc-shaped arm 140b also functions as the displacement electrode E0. Here, the relationship between the fixed electrode E3 and the displacement electrode E0 facing the fixed electrode E3 and the relationship between the fixed electrode E4 and the displacement electrode E0 facing the same are the relationships described in FIG.

  34 also shows fixed electrodes E5, E6, and E7 fixed to the upper surface of the bottom plate portion 210 (the fixed electrode E8 is not shown in FIG. 34, but is located on the front side of the paper surface). Further, in FIG. 34, a portion facing the fixed electrode E5 and a portion facing the fixed electrode E6 on the lower surface of the inner member 110b are indicated by bold lines. The thick line portions function as a displacement electrode E0 facing the fixed electrode E5 and a displacement electrode E0 facing the fixed electrode E6, respectively.

  In the case of the embodiment shown here, the upper basic structure 100a, the intermediate substrate 500, and the lower basic structure 100b are all made of a conductive material such as metal, and therefore the displacement electrodes E0 indicated by bold lines in the figure are mutually connected. It is electrically conductive and functions as a common electrode. On the other hand, since the support substrate 200 is made of an insulating material such as resin, the fixed electrodes E5 to E8 each function as an electrically independent individual electrode. Of course, the support substrate 200 can be made of a conductive material such as metal. In that case, the fixed electrodes E5 to E8 need to be fixed to the upper surface of the bottom plate portion 210 via an insulating layer.

  FIG. 35 (a) is a cross-sectional view showing a state in which the force sensor according to the two-layer stacked embodiment shown in FIG. 34 is cut along the XaYa plane, and FIG. 35 (b) is a cross-sectional view along the XbYb plane. It is a cross-sectional view which shows the state cut | disconnected (E5-E8 shown with the circle of a broken line has shown the position of each fixed electrode arrange | positioned on the support substrate 200). Of course, as in the embodiments described so far, the capacitive elements C1 to C8 are formed by the fixed electrodes E1 to E8 and the individual displacement electrodes E0 facing the fixed electrodes E1 to E8.

  As described above, the embodiment shown here is an example (combination of number 1) using the basic structure 100L as the upper basic structure 100a and the basic structure 100LL as the lower basic structure 100b. The upper basic structure 100a shown in (a) is the same as the basic structure 100L shown in FIG. 22 (a), and the lower basic structure 100b shown in FIG. 35 (b) is shown in FIG. 23 (a). It is the same as the basic structure 100LL.

  As shown in FIG. 35 (a), support members S1 to S4 are arranged on the Xa axis and the Ya axis at the outer positions of the arc-shaped arm portions. Further, as shown in FIG. 35 (b), support members S1 to S4 are also arranged on the Xb axis and the Yb axis at the outer positions of the respective arc-shaped arm portions. As described above, the support members S1 to S4 are insulating plate-like members extending upward from the upper surface of the bottom plate portion 210, and penetrate through both the gap portions of the lower basic structure 100b and the upper basic structure 100a. Are arranged to be.

  On the other hand, the fixed electrodes E1 and E2 are electrodes arranged near the position of the upper basic structure 100a of the support members S1 and S2, and the fixed electrodes E3 and E4 are lower basic structures of the support members S3 and S4. It is an electrode arranged near the position of the body 100b. For this reason, FIG. 35 (a) shows the cross-sections of the fixed electrodes E1 and E2 arranged in the vicinity of the measurement points H11 and H12, and the displacement electrodes (thick line portions) on the surface side of the arcuate arm facing this. (Fixed electrodes E3 and E4 appearing in FIG. 35 (a) are electrodes arranged not on the XaYa plane but on the XbYb plane located below the XaYa plane).

  Similarly, FIG. 35 (b) shows a cross section of the fixed electrodes E3 and E4 arranged in the vicinity of the measurement points H13 and H14, and a displacement electrode (thick line portion) on the arc-shaped arm surface side facing this. (In the position of the XbYb plane, no fixed electrode is formed on the support members S1 and S2.) Further, in FIG. 35 (b), the positions of the four disk-shaped fixed electrodes E5 to E8 formed on the upper surface of the bottom plate portion 210 are indicated by broken-line circles. These fixed electrodes E5 to E8 are electrodes arranged in the vicinity of the illustrated measurement points H15 to H18. Here, the measurement point H15 is a point on the Xb-axis positive region, the measurement point H16 is a point on the Xb-axis negative region, the measurement point H17 is a point on the Yb-axis positive region, and the measurement point H18 is a point on the Yb-axis negative region. And both are defined as points equidistant from the origin Ob.

  After all, the upper basic structure 100a and the fixed electrodes E1 and E2 shown in FIG. 35 (a) are equivalent to the basic structure 100L and the electrodes E1 and E2 shown in FIG. 22 (a) and are shown in FIG. 35 (b). The lower basic structure 100b and the fixed electrodes E3 and E4 are equivalent to the basic structure 100LL and the electrodes E3 and E4 shown in FIG. Therefore, the combination of number 1 in the table of FIG. 25 can be applied (of course, the combination of number 1 in the table of FIG. 27 may be applied). On the other hand, the lower basic structure 100b and the fixed electrodes E5 to E8 shown in FIG. 35 (b) are equivalent to the basic structure 100 and the fixed electrodes E9 to E12 shown in FIG. 13 (a). The column C9 to C12 in the table in FIG.

  Therefore, as a table showing changes in capacitance values of the capacitive elements C1 to C8 when a force in the direction of each coordinate axis and a moment around each coordinate axis are applied to the force sensor having the structure shown in FIG. The table shown in FIG. 36 is obtained (both indicate positive signs of external force, but when negative signs of external force are applied, the result of reversing the sign of each column is obtained). Here, the + Fx, + Fy, + Mz columns of C1 to C4 in the table shown in FIG. 36 are the corresponding columns of number 1 in the table of FIG. 25, and the + Fz, + Mx, + My columns are shown in FIG. The “common” column of the table in FIG. 15 is transcribed, and the columns C5 to C8 are transcribed by replacing the C9 to C12 columns in FIG. 15B with the C5 to C8 columns.

Based on the results shown in the table of FIG. 36, in the case of the force sensor having the structure shown in FIG. 35, the detection circuit 300 performs an operation based on the arithmetic expression of FIG.
Fx = (C1 + C4) − (C2 + C3)
Fy = (C1 + C3) − (C2 + C4)
Fz = − (C5 + C6 + C7 + C8)
Mx = −C7 + C8
My = + C5-C6
Mz = C1 + C2 + C3 + C4
When the following calculation is performed, the detected values of the force Fx in the X axis direction, the force Fy in the Y axis direction, the force Fz in the Z axis direction, the moment Mx around the X axis, the moment My around the Y axis, and the moment Mz around the Z axis Can be obtained respectively. In addition, as can be seen from the results shown in the table of FIG. 36, the detection values calculated based on the above-described arithmetic expressions do not include other axis components. Can be obtained.

  Of course, the above arithmetic expression is for an example (combination of number 1) in which the basic structure 100L is used as the upper basic structure 100a and the basic structure 100LL is used as the lower basic structure 100b. When a combination is employed, an arithmetic expression corresponding to the combination needs to be used.

<4-4. Advantages of the two-stage stacked embodiment>
In §2, a force sensor according to a basic embodiment as illustrated in FIG. 13 is described, and in §4, a force sensor according to a two-layer stacked embodiment as illustrated in FIG. 35 is described. did. Both of them have a function of independently obtaining detection values of six-axis components of forces Fx, Fy, Fz and moments Mx, My, Mz. Here, in the former, it is only necessary to use a single basic structure 100, whereas in the latter, it is necessary to use two sets of basic structures 100a and 100b, so in terms of the number of basic structures. The former is simpler in structure.

  However, the former requires a total of 12 fixed electrodes E1 to E12 as shown in FIG. 13, whereas the latter requires only a total of 8 fixed electrodes E1 to E8 as shown in FIG. Therefore, the latter is simpler in terms of electrode configuration.

  The remarkable merit of the latter over the former is that it becomes easy to adjust the balance of detection sensitivity of each axis component of force and moment. This advantage can be clearly seen by looking at the table in FIG. This table shows the force sensor according to the basic embodiment shown in FIG. 13 (the basic structure is stacked in one stage) and the force sensor according to the two-layer stacked embodiment shown in FIG. Capacitance elements used for obtaining respective detection values when 6-axis components of forces Fx, Fy, Fz and moments Mx, My, Mz are applied to The average displacement amount (DELTA) (unit: micrometer) of (capacitance element in which an electrostatic capacitance value is used for the calculation formula of each detection value) is shown as a result of an experiment.

  In this experiment, six-axis components of forces Fx, Fy, Fz and moments Mx, My, Mz are applied to the inner member (laminated inner member) in a state where the outer member (laminate outer member) is fixed. Specifically, as the forces Fx, Fy, and Fz, a force of 25N is applied, and as the moments Mx, My, and Mz, a moment of 25N · cm is applied.

  In this table, the average displacement amount Δ is a parameter indicating the detection sensitivity for the applied external force component, and the external force component for which the average displacement amount Δ is large indicates higher detection sensitivity. In general applications, it is preferable that the detection sensitivities of the six-axis components be as similar as possible.

  From this point of view, in the case of a one-stage force sensor, there is a large difference between the detection sensitivity “80” of the force Fx and the detection sensitivity “15” of the force Fy. You can see that it has occurred. As can be seen from FIG. 13 (a), the two arc-shaped arms 130 and 140 are both arms having end points in the vicinity of the Y axis, and are easily displaced in the X axis direction. This is because the structure is difficult to displace in the Y-axis direction.

  On the other hand, in the case of a two-stage force sensor, the detection sensitivity of the force Fx and the detection sensitivity of the force Fy are both “19”, and there is no difference between the two sensitivities. As shown in FIG. 35, the upper basic structure 100a and the lower basic structure 100b are in a positional relationship rotated by 90 °. This is because there is no difference between the ease of displacement and the ease of displacement in the Y-axis direction.

  Of course, the same can be said about the detection sensitivity of the moment. In other words, in the case of the one-step stacked force sensor, there is a large difference between the detection sensitivity “140” of the moment Mx and the detection sensitivity “70” of the moment My. In this case, the detection sensitivity of the moment Mx and the detection sensitivity of the moment My are both “35”, and there is no difference between the two sensitivities.

  The two-stage force sensor can also correct the difference between the force detection sensitivity and the moment detection sensitivity. For example, in the case of a one-stage force sensor, the detection sensitivity “140” of the moment Mx is 1.40 times the detection sensitivity “100” of the force Fz, whereas In the case of the force sensor, the detection sensitivity “35” of the moment Mx is 0.78 times the detection sensitivity “45” of the force Fz, and the sensitivity difference is corrected.

  As described above, the two-stage stacked embodiment is characterized in that the balance of detection sensitivity of each axis component of force and moment is adjusted.

<4-5. Basic Technical Concept of Two-tiered Stacking Embodiment>
Finally, the basic technical concept of the force sensor according to the embodiment of the two-stage stacking type described in §4 is summarized. In the force sensor according to the two-layered embodiment, two sets of the basic structures 100 described in §1 and the elastic deformation of the arc-shaped arms 130 and 140 of the two sets of the basic structures 100 are eventually electrically generated. In the state where one of the inner member 110 of the two sets of basic structures 100 and the outer member 120 of the two sets of basic structures 100 is fixed based on the detection element to be detected automatically and the detection result of the detection elements, the other A detection circuit that outputs a detection value of a force in a predetermined coordinate axis direction or a moment around the predetermined coordinate axis acting on the sensor.

  In the case of the above-described embodiment, the two sets of the basic structures 100 are arranged so as to be adjacent in the vertical direction with the Z axis as the vertical axis. The member 120 is connected by the first arc-shaped arm 130 and the second arc-shaped arm 140, and is a predetermined plane parallel to the XY plane (specifically, the XaYa plane shown in FIG. When the XbYb plane shown in FIG. 35 (b) is defined as an arrangement plane, the first inner connection point P1, the second inner connection point P2, the first outer connection point Q1, the first Two outer connection points Q2 are arranged.

  In the description of the above-described embodiments, one of the two sets of basic structures 100 arranged above is called the upper basic structure 100a, and the other arranged below is called the lower basic structure 100b. .

  As shown in FIG. 32, an inner intermediate member 510 is provided between the lower surface of the inner member 110a of the upper basic structure 100a and the upper surface of the inner member 110b of the lower basic structure 100b. An outer intermediate member 520 is provided between the lower surface of the outer member 120a of the upper basic structure 100a and the upper surface of the outer member 120b of the lower basic structure 100b.

  As a result, the inner member 110a, the inner intermediate member 510 of the upper basic structure 100a, and the inner member 110b of the lower basic structure 100b are connected to each other, and the whole functions as a laminated inner member. Similarly, the outer member 120a of the upper basic structure 100a, the outer intermediate member 520, and the outer member 120b of the lower basic structure 100b are connected to each other, and the whole functions as a laminated outer member.

  For both the upper basic structure 100a and the lower basic structure 100b, detection elements that electrically detect the elastic deformation of the arc-shaped arms 130a, 140a, 130b, 140b (capacitance elements C1 to C8 in the above-described embodiment). ) And the detection circuit 300, based on the detection results of these detection elements, in a state where one of the laminated inner member and the laminated outer member is fixed, the force in the predetermined coordinate axis direction or the predetermined coordinate axis applied to the other The detected value of moment is output.

  Actually, the upper basic structure 100a and the lower basic structure 100b are geometrically congruent structures, and both are arranged with the Z axis as a common central axis. When the combination described as number 1 or number 3 in the table of FIG. 25 is adopted, the lower basic structure 100b is arranged in a direction in which the upper basic structure 100a is rotated by 90 ° about the Z axis. It becomes the structure.

  More specifically, when the combination described as No. 1 or No. 3 is adopted, as the upper basic structure 100a, the first inner connection point P1 projects the negative region of the Y axis onto the arrangement plane. The second inner connection point P2 is arranged on or near the image, the second inner connection point P2 is arranged on or near the projected image of the positive region of the Y axis on the arrangement plane, and the first outer connection point Q1 is arranged on the arrangement plane. Basically arranged on or near the projected image of the positive area of the Y axis on the upper side, and the second outer connection point Q2 is arranged on or near the projected image of the negative area of the Y axis on the arrangement plane A structure may be used.

  In this case, when the rotation direction in which the right screw is advanced in the Z-axis positive direction is defined as a counterclockwise direction, and the rotation direction in which the right screw is advanced in the Z-axis negative direction is defined as a clockwise direction, the first arcuate arm is Direction from the inner connection point P1 to the first outer connection point Q2 in either the left-handed direction (in the case of the basic structure 100L) or the right-handed direction (in the case of the basic structure 100R). The second arcuate arm extends in the same direction as the selection direction from the second inner connection point P2 toward the second outer connection point Q2.

  Further, as the lower basic structure 100b, a structure in which a structure that is geometrically congruent with the upper basic structure 100a described above is arranged in a direction rotated by 90 ° about the Z axis as a rotation axis is used. do it.

  On the other hand, when the combination described as number 2 or number 4 in the table of FIG. 25 is adopted, the upper basic structure 100a and the lower basic structure 100b may be geometrically congruent structures. Both may be arranged with the Z axis as a common central axis. However, in this case, the lower basic structure 100b is arranged in a direction in which the upper basic structure 100a is rotated by 180 ° about the X axis or Y axis as a rotation axis and further rotated by 90 ° about the Z axis as a rotation axis. Become a body.

  More specifically, when the combination described as No. 2 or No. 4 is adopted, as the upper basic structure 100a, the first inner connection point P1 is arranged on the Y-axis on the arrangement plane (XaYa plane). The projection image of the positive region of the Y axis on the placement plane (XaYa plane) is arranged on or near the projection image of the negative region (negative region of the Ya axis), and the second inner connection point P2 The first outer connection point Q1 is arranged on or near the projected image of the Y-axis positive area (Ya-axis positive area) on the arrangement plane (XaYa plane). The basic structure in which the second outer connection point Q2 is arranged on or near the projected image of the negative area of the Y axis (Ya axis negative area) on the arrangement plane (XaYa plane) may be used. .

  In this case, when the rotation direction in which the right screw is advanced in the Z-axis positive direction is defined as a counterclockwise direction, and the rotation direction in which the right screw is advanced in the Z-axis negative direction is defined as a clockwise direction, the first arcuate arm is From the inner connection point P1 to the first outer connection point Q1, in the selection direction of either the left-handed direction (in the case of the basic structure 100L) or the right-handed direction (in the case of the basic structure 100R) The second arcuate arm extends in the same direction as the selection direction from the second inner connection point P2 toward the second outer connection point Q2.

  Further, as the lower basic structure 100b, a structure that is geometrically congruent with the upper basic structure 100a described above is rotated by 180 ° about the X axis or the Y axis as the rotation axis, and the Z axis is the rotation axis. It is sufficient to use a structure disposed in a direction rotated by 90 °.

  The arrangement of the detection elements may be as follows. First, for the upper basic structure 100a, the first measurement point H11 is the intersection of the projected image of the X-axis positive region (Xa-axis positive region) on the arrangement plane (XaYa plane) and the center line of the arcuate arm. And a second measurement point H12 is defined at the intersection of the projected image of the negative region of the X axis (Xa axis negative region) on the arrangement plane (XaYa plane) and the center line of the arc-shaped arm (FIG. 22). reference). Next, for the lower basic structure 100b, the third measurement point is at the intersection of the projected image of the positive area of the Y axis (the positive area of the Yb axis) on the arrangement plane (XbYb plane) and the center line of the arc arm. H13 is defined, and a fourth measurement point H14 is defined at the intersection of the projected image of the negative region of the Y axis (the negative region of the Yb axis) on the arrangement plane (XbYb plane) and the center line of the arcuate arm (see FIG. 23). And what is necessary is just to make it a detection element detect the elastic deformation of each arc-shaped arm by electrically detecting the displacement of the 1st-4th measurement points H11-H14.

  When a capacitive element is used as the detection element, a first capacitive element C1 disposed in the vicinity of the first measurement point H11, a second capacitive element C2 disposed in the vicinity of the second measurement point H12, What is necessary is just to provide the 3rd capacitive element C3 arrange | positioned in the vicinity of the 3rd measurement point H13, and the 4th capacitive element C4 arrange | positioned in the vicinity of the 4th measurement point H14.

  Here, the first capacitive element C1 includes a first fixed electrode E1 disposed in the vicinity of the first measurement point H11 outside or inside the arc-shaped arm and fixed to the laminated inner member or the laminated outer member, and the arc-shaped arm. And a first displacement electrode E0 formed in a region facing the first fixed electrode E1 on the surface of the capacitor.

  The second capacitive element C2 includes a second fixed electrode E2 disposed near the second measurement point H12 outside or inside the arc-shaped arm and fixed to the laminated inner member or the laminated outer member, and the arc-shaped arm. It is a capacitive element constituted by a second displacement electrode E0 formed in a region facing the second fixed electrode E2 on the surface.

  The third capacitive element C3 includes a third fixed electrode E3 disposed in the vicinity of the third measurement point H13 outside or inside the arc-shaped arm and fixed to the laminated inner member or the laminated outer member, and the arc-shaped arm. It is a capacitive element constituted by a third displacement electrode E0 formed in a region facing the third fixed electrode E3 on the surface.

  The last fourth capacitive element C4 is disposed in the vicinity of the fourth measurement point H14 outside or inside the arcuate arm and fixed to the laminated inner member or laminated outer member, and the arcuate arm It is a capacitive element constituted by a fourth displacement electrode E0 formed in a region facing the fourth fixed electrode E4 on the surface.

  The detection circuit, based on the detection results of the detection elements constituted by these capacitive elements C1 to C4, in a state in which one of the laminated inner member and the laminated outer member is fixed, the X-axis direction forces Fx and Y acting on the other Detection values of the axial force Fy and the moment Mz around the Z-axis can be output.

  In order to obtain the detection values for all six axes, in addition to the first to fourth measurement points H11 to H14 described above, the detection is further performed at a predetermined position on the arc-shaped arm or the inner member of the lower basic structure 100b. The fifth to eighth measurement points H15 to H18 may be defined (see FIG. 35 (b)). Here, the fifth measurement point H15 is arranged on or near the projection image (Xb-axis positive area) of the X-axis positive area onto the arrangement plane (XbYb plane) of the lower basic structure. The sixth measurement point H16 is arranged on or near the projection image (Xb-axis negative region) of the negative region of the X axis onto the arrangement plane (XbYb plane) of the lower basic structure, and the seventh measurement point. H17 is arranged on or near the projected image of the Y-axis positive area (Yb-axis positive area) onto the arrangement plane (XbYb plane) of the lower basic structure, and the eighth measurement point H18 is What is necessary is just to make it arrange | position on the projection image (negative area | region of a Yb axis | shaft) of the negative area | region of a Y-axis on the arrangement | positioning plane (XbYb plane) of a basic structure, or its vicinity position.

  As detection elements, a fifth capacitive element C5 arranged in the vicinity of the fifth measurement point H15, a sixth capacitive element C6 arranged in the vicinity of the sixth measurement point H16, and a seventh element The seventh capacitive element C7 disposed in the vicinity of the second measurement point H17 and the eighth capacitive element C8 disposed in the vicinity of the eighth measurement point H18 are provided.

  Here, the fifth capacitive element C5 is arranged in the vicinity of the fifth measurement point H15 below the arc-shaped arm of the lower basic structure 100b or the inner member, and is fixed to the outer member of the lower basic structure 100b. And a fifth displacement electrode E0 formed in a region facing the fifth fixed electrode E5 on the lower surface of the arc-shaped arm or inner member of the lower basic structure 100b. .

  The sixth capacitive element C6 is arranged in the vicinity of the arc-shaped arm of the lower basic structure 100b or the sixth measurement point H16 below the inner member, and is fixed to the outer member of the lower basic structure 100b. The capacitive element is configured by the fixed electrode E6 and the sixth displacement electrode E0 formed in a region facing the sixth fixed electrode E6 on the lower surface of the arc-shaped arm or the inner member of the lower basic structure 100b.

  The seventh capacitive element C7 is disposed in the vicinity of the arcuate arm of the lower basic structure 100b or the seventh measurement point H17 below the inner member, and is fixed to the outer member of the lower basic structure 100b. This is a capacitive element constituted by the fixed electrode E7 and the seventh displacement electrode E0 formed in a region facing the seventh fixed electrode E7 on the lower surface of the arc-shaped arm or inner member of the lower basic structure 100b.

  The last eighth capacitive element C8 is arranged in the vicinity of the arc-shaped arm of the lower basic structure 100b or the eighth measurement point H18 below the inner member, and is fixed to the outer member of the lower basic structure 100b. The capacitive element includes the fixed electrode E8 and an eighth displacement electrode E0 formed in a region facing the eighth fixed electrode E8 on the lower surface of the arc-shaped arm or inner member of the lower basic structure 100b.

  The detection circuit, based on the detection results of the detection elements constituted by these capacitive elements C1 to C8, in the state where one of the laminated inner member and the laminated outer member is fixed, the X-axis direction forces Fx and Y acting on the other Detection values of the axial force Fy, the Z-axis force Fz, the X-axis moment Mx, the Y-axis moment My, and the Z-axis moment Mz can be output.

  In the case of the example shown in FIG. 34, the support substrate 200 is disposed below the lower basic structure 100b. The support substrate 200 includes a bottom plate portion 210 that faces the lower basic structure 100b, and an edge peripheral portion 220 that protrudes upward from the periphery of the bottom plate portion 210, and the outer member 120b of the lower basic structure 100b. The lower surface is fixed to the upper surface of the peripheral edge portion 220, and a cavity portion 250 is formed between the lower surface of the inner member 110b of the lower basic structure 100b and the upper surface of the bottom plate portion 210. 110a, 510, 110b) are supported by arcuate arms so as to be displaceable in the surrounding space including the cavity 250. The first to eighth fixed electrodes E1 to E8 are fixed to the upper surface of the bottom plate portion 210.

<<< §5. Other variations >>
Finally, some further variations on the various embodiments described so far are listed.

  FIG. 39 is a cross-sectional view (showing a cross section taken along the XY plane) of a basic structure 100L showing a modification of the electrode configuration in the force sensor according to the present invention. In the vicinity of the measurement point H11 on the right side of the figure, a fixed electrode EA supported by the support member SA and a fixed electrode EB supported by the support member SB are shown. FIG. 13 shows an example in which the fixed electrodes E1 to E12 are directly fixed to the upper surface of the bottom plate portion 210 of the support substrate 200. However, when the bottom plate portion 210 is made of a conductive material such as metal, As in the example shown in FIG. 39, it is necessary to fix the fixed electrodes EA and EB to the upper surface of the bottom plate portion 210 via the support members SA and SB made of an insulating material.

  On the other hand, in the vicinity of the measurement point H12 on the left side of FIG. 39, a displacement electrode EC is formed via a support member SC made of an insulating material, and a fixed electrode ED is placed at a position opposite to this via a support member SD. The state which fixed to the upper surface of the baseplate part 210 is shown. The reason why the displacement electrode EC is wider than the fixed electrode ED is to maintain the relationship described in FIG. 14 between the two electrodes.

  According to the basic principle of measuring the distance between the surface to be measured in the vicinity of the measurement point H12 (the outer surface of the arc-shaped arm 140L) and the opposite reference surface (the surface of the support member SD), as shown in the figure. It can be said that the capacitive element is configured by separately providing the displacement electrode EC and the fixed electrode ED.

  However, in the embodiments described so far, since the basic structure 100L is made of a conductive material such as metal, individual partial regions on the surface of the basic structure 100L are used as displacement electrodes. For example, as the displacement electrode of the capacitive element for detecting the displacement of the measurement point H11 on the right side of FIG. 39, a part of the surface of the arc-shaped arm 130L is substituted as shown by a thick line in the drawing. In this way, if the basic structure 100L is made of a conductive material such as metal, the partial region on the surface can be used as an individual displacement electrode, so that the electrode configuration is simplified and the wiring is also simple. It becomes.

  However, since the basic structure 100L is a large structure that occupies the main structure of the force sensor, it cannot be denied that it is affected by electrical noise. In addition, there is a concern that an unnecessary capacitive element may be formed at a location that is not originally intended.

  For example, in the example shown in FIG. 39, the fixed electrode EA faces the displacement electrode (thick line portion) formed on the outer surface in the vicinity of the measurement point H11 of the arc-shaped arm 130L, and the capacitive element CA is formed by both electrodes. Will be. The capacitive element CA thus formed is a detection element as intended. However, since the fixed electrode EA also faces the inner side surface of the outer member 120L made of a conductive material, an unexpected capacitive element is formed between the fixed electrode EA and the inner side facing surface of the outer member 120L. Will be.

  Of course, in actuality, the fixed electrode EA is disposed in the vicinity of the arc-shaped arm 130L and is disposed at a position away from the outer member 120L (as described above, each figure of the present application is deformed for convenience of explanation). However, the influence of the above-described unexpected capacitance element is very small, but it cannot be denied that it causes electrical noise components. In addition, when the outer member 120L is used while being fixed to the device housing of the sensor, an electrical noise component is mixed through the device housing.

  As in the example shown in the vicinity of the measurement point H12 on the left side of FIG. 39, if a displacement electrode is formed on the surface of the arc-shaped arm (or inner member) via an insulating layer, the capacitive element is configured. Electrode formation and wiring work are complicated, but such an electrical noise component can be eliminated.

  By the way, in §4, an embodiment of a two-stage stacking type in which two sets of basic structures are stacked in the vertical direction has been described. Of course, three or more sets of basic structures may be stacked. As described in general terms, the force sensor according to the embodiment in which a plurality of basic structures are stacked in the vertical direction will be described as a general theory. A plurality of m sensors (m That is, a force sensor having a basic structure of ≧ 2).

  Here, when the plurality of m basic structures are referred to as the first to mth basic structures from the top to the bottom with the Z axis as the vertical axis, the jth (1 ≦ j ≦ m−1) The lower surface of the inner member of the basic structure is connected to the upper surface of the inner member of the (j + 1) th basic structure, and the lower surface of the outer member of the jth (1 ≦ j ≦ m−1) basic structure and the The upper surface of the outer member of the basic structure (j + 1) is connected. Then, the m inner members connected to each other function as a laminated inner member, and the m outer members connected to each other function as a laminated outer member.

  The detection element is configured to electrically detect the elastic deformation of all the arc-shaped arms of the plurality of m basic structures or a part of the arc-shaped arms selected from them, and the detection circuit is configured to detect the detection result of the detection element. On the basis of this, in a state where one of the laminated inner member and the laminated outer member is fixed, a detection value of a force acting on the other coordinate axis direction or a moment around the given coordinate axis may be output.

  When a support substrate is provided in the lowermost layer, the support substrate may be disposed below the mth basic structure. The support substrate is a structure having a bottom plate portion facing the m-th basic structure and an edge peripheral portion protruding upward from the periphery of the bottom plate portion. Then, the lower surface of the outer member of the mth basic structure is fixed to the upper surface of the peripheral edge portion, and a cavity is formed between the lower surface of the inner member of the mth basic structure and the upper surface of the bottom plate portion, The laminated inner member may be supported by the arc-shaped arm so as to be displaceable in the surrounding space including the cavity.

100, 100L, 100LL, 100R, 100RR: Basic structure 100a: Upper basic structure 100b: Lower basic structure 110, 110a, 110b, 110L, 110R: Inner member 120, 120a, 120b, 120L, 120R: Outer member 130 , 130a, 130L, 130R: first arc-shaped arms 131, 131L: arc-shaped portions 132, 132L of the first arc-shaped arm: inner connection portions 133, 133L of the first arc-shaped arm: outer connections of the first arc-shaped arm Portions 140, 140a, 140L, 140R: second arc-shaped arms 141, 141L: arc-shaped portions 142, 142L of the second arc-shaped arm: inner connecting portions 143, 143L of the second arc-shaped arm: of the second arc-shaped arm Outer connection part 200: support substrate 210: bottom plate part 220: peripheral edge part 250: cavity part 300 Detection circuits 301 to 312: C / V conversion circuits 321 to 326: addition / subtraction circuit 400: basic structure 410: inner member 420: outer member 430: first arcuate arm 440: second arcuate arm 450: third arcuate Arm 500: Intermediate substrate 510: Inner intermediate member 520: Outer intermediate member A: Counter area (projected image of electrode Eb)
C1 to C12: Capacitance element / Capacitance element capacitance value E0: Common displacement electrode (surface of basic structure made of conductive material)
E1-E12, E9'-E12 ': Fixed electrodes EA, Ea, EB, Eb, EC, ED: Electrodes Fx: Force in the X-axis direction Fy: Force in the Y-axis direction Fz: Forces in the Z-axis direction G1-G4: On-axis points H1 to H18, H5 'to H8': Measurement point Mx: Moment about X axis My: Moment about Y axis Mz: Moment about Z axis O: Origin of XYZ three-dimensional orthogonal coordinate system Oa: XaYaZ cubic Origin Ob of the original Cartesian coordinate system Ob: Origin P1: XbYbZ Three-dimensional Cartesian coordinate system P1: First inner connection point P2: Second inner connection point P3: Third inner connection point Q1: First outer connection point Q2: Second outer connection point Q3: Third outer connection points R1, R2: Arrows indicating displacement directions S1 to S4: Support members SA, SB, SC, SD: Support member U1: Counterclockwise with respect to the Y axis Coordinate axis U2 forming 120 °: Hour relative to Y axis Coordinate axes V1 to V12 forming 120 ° around: Voltage signal W1: Coordinate axis forming 45 ° counterclockwise with respect to the X axis W2: Coordinate axis forming 45 ° counterclockwise with respect to the Y axis X: XYZ three-dimensional Cartesian coordinate system Xa: XaYaZ three-dimensional Cartesian coordinate system Xb: XbYbZ three-dimensional Cartesian coordinate system Y: XYZ three-dimensional Cartesian coordinate system Ya: XaYaZ three-dimensional Cartesian coordinate system Yb: XbYbZ three-dimensional Coordinate axis Z of Cartesian coordinate system: Coordinate axis of XYZ three-dimensional Cartesian coordinate system

Claims (34)

A force sensor for detecting a force or a moment related to at least one of a force in each coordinate axis direction and a moment around each coordinate axis in an XYZ three-dimensional orthogonal coordinate system,
An inner member disposed on the Z-axis of the XYZ three-dimensional orthogonal coordinate system;
An outer member disposed so as to surround the Z axis, and containing the inner member therein;
It plays the role of connecting the inner member and the outer member, has the property of causing elastic deformation at least in part by the action of the force or moment to be detected, and so as to partially surround the inner member A plurality of arranged n (n ≧ 2) arcuate arms;
A plurality of m (m ≧ 2) basic structures having
A detection element for electrically detecting elastic deformation of the arcuate arm;
A detection circuit that outputs a detection value of a force in a predetermined coordinate axis direction acting on the other or a moment around a predetermined coordinate axis in a state where one of the inner member and the outer member is fixed based on a detection result of the detection element When,
With
Of the plurality of n arcuate arms, the inner end of the i-th (1 ≦ i ≦ n) arcuate arm is connected to the i-th inner connection point on the inner member, and the outer end is on the outer member. Are connected to the i-th outer connection point, the first to n-th inner connection points are at different positions on the inner member, and the first to n-th outer connection points are the outer sides. Is in a different position on the member ,
The plurality of m (m ≧ 2) basic structures are arranged vertically adjacent to each other at a predetermined interval,
When the plurality of m basic structures are referred to as first to mth basic structures from the top to the bottom with the Z axis as the vertical axis, the jth (1 ≦ j ≦ m−1) The lower surface of the inner member of the basic structure and the upper surface of the inner member of the (j + 1) th basic structure are connected, and the lower surface of the outer member of the jth (1 ≦ j ≦ m−1) basic structure and the ( j + 1) is connected to the upper surface of the outer member of the basic structure,
The m inner members connected to each other function as a laminated inner member, and the m outer members connected to each other function as a laminated outer member.
The detection element electrically detects an elastic deformation of the whole arc-shaped arm of the plurality of m basic structures or a part of the arc-shaped arm selected therefrom, and the detection circuit detects a detection result of the detection element. Based on the above, in a state in which one of the laminated inner member and the laminated outer member is fixed, a force in the predetermined coordinate axis direction acting on the other or a detected value of a moment around the predetermined coordinate axis is output. Sense sensor. The force sensor according to claim 1,
The inner member has a top surface and a bottom surface parallel to the XY plane, and is constituted by a disk-shaped member arranged so that the Z axis is the central axis.
The outer member has an upper surface and a lower surface parallel to the XY plane, and is configured by an annular member arranged so that the Z axis is the central axis.
The force sensor, wherein the disk-shaped member is accommodated in the annular member. The force sensor according to claim 2,
n = 2, the inner member and the outer member are connected by the first arcuate arm and the second arcuate arm,
An XY plane or a predetermined plane parallel to the XY plane is defined as an arrangement plane, and on this arrangement plane, a first inner connection point, a second inner connection point, a first outer connection point, and a second outer connection Points are arranged, and a connecting straight line connecting the first inner connecting point and the second inner connecting point and a connecting straight line connecting the first outer connecting point and the second outer connecting point respectively intersect the Z axis. A force sensor characterized by the above. The force sensor according to claim 3, wherein
A first arcuate arm extending along an arc centered on the Z axis, and a first inner connection connecting one end of the first arcuate part to a first inner connection point; And a first outer connecting portion that connects the other end of the first arc-shaped portion to a first outer connecting point,
A second arcuate arm extending along an arc centered on the Z-axis, and a second inner connection connecting one end of the second arcuate part to a second inner connection point And a second outer connecting portion that connects the other end of the second arc-shaped portion to a second outer connecting point. The force sensor according to claim 3 or 4,
A force sensor characterized by having a 180 [deg.] Rotationally symmetric structure in which the basic structure has the same shape when rotated 180 [deg.] About the Z axis as the rotation axis. The force sensor according to claim 2,
n = 3 so that the inner member and the outer member are connected by the first arcuate arm, the second arcuate arm, the third arcuate arm,
An XY plane or a predetermined plane parallel to the XY plane is defined as an arrangement plane, and on this arrangement plane, a first inner connection point, a second inner connection point, a third inner connection point, and a first outer connection A point, a second outer connection point, a third outer connection point, a connecting straight line connecting the first inner connection point and the first outer connection point, the second inner connection point and the second outer connection A force sensor characterized in that a connecting straight line connecting points and a connecting straight line connecting a third inner connecting point and a third outer connecting point each intersect with the Z axis. The force sensor according to claim 6, wherein
A first curved portion in which the first arcuate arm partially surrounds the periphery of the Z axis; a first inner connection portion that connects one end of the first curved portion to a first inner connection point; A first outer connecting portion for connecting the other end of the first bending portion to the first outer connecting point;
A second curved portion in which the second arcuate arm partially surrounds the periphery of the Z-axis; a second inner connection portion that connects one end of the second curved portion to a second inner connection point; A second outer connecting portion that connects the other end of the second bending portion to a second outer connecting point;
A third curved portion in which a third arcuate arm partially surrounds the periphery of the Z-axis; a third inner connection portion that connects one end of the third curved portion to a third inner connection point; A force sensor comprising: a third outer connecting portion that connects the other end of the third bending portion to a third outer connecting point. The force sensor according to claim 6 or 7,
A force sensor characterized in that the basic structure has a 120 [deg.] Rotationally symmetric structure in which the shape when rotated by 120 [deg.] About the Z axis is the same as the shape before rotation. The force sensor according to claim 2,
The inner member and the outer member are connected by a total of n arcuate arms that are first to nth arcuate arms,
The basic structure has a (360 / n) ° rotationally symmetric structure in which the shape when rotated by (360 / n) ° about the Z axis is the same as the shape before rotation. Force sensor. The force sensor according to any one of claims 1 to 9,
A force sensor, wherein the inner member and the outer member are constituted by a rigid body that does not substantially deform as long as an applied force or moment is within a predetermined allowable range. The force sensor according to any one of claims 1 to 10 ,
A support substrate disposed below the m-th basic structure;
The support substrate has a bottom plate portion facing the m-th basic structure, and an edge peripheral portion protruding upward from the periphery of the bottom plate portion,
The lower surface of the outer member of the m-th basic structure is fixed to the upper surface of the peripheral edge portion, and a cavity is formed between the lower surface of the inner member of the m-th basic structure and the upper surface of the bottom plate portion. The force sensor is characterized in that the laminated inner member is supported by an arc-shaped arm so as to be displaceable in the surrounding space including the cavity. The force sensor according to any one of claims 1 to 11 ,
A force sensor, wherein the detection element detects elastic deformation of the arcuate arm by electrically detecting a displacement of a predetermined measurement point of the arcuate arm. The force sensor according to claim 12 , wherein
The detection element is configured to electrically detect a distance between a measurement target surface in the vicinity of a predetermined measurement point of the arc-shaped arm and an opposing reference surface fixed to the inner member or the outer member and facing the measurement target surface. Force sensor. The force sensor according to claim 13 ,
Define the side measurement surface near the measurement point on the inner or outer surface of the arc arm,
It has a side-facing reference plane facing this side-side measurement target surface, and further includes a fixed structure fixed to the inner member or the outer member,
A force sensor, wherein the detection element electrically detects a distance between the side measurement target surface and the side opposite reference surface. The force sensor according to claim 14 , wherein
An additional measurement point is further provided at a predetermined position of the inner member or the arc-shaped arm, and a lower measurement target surface is defined in the vicinity of the additional measurement point on the lower surface of the inner member or the arc-shaped arm,
A force sensor, wherein the detection element electrically detects a distance between the lower measurement target surface and a lower facing reference surface fixed to an outer member and facing the lower measurement target surface. The force sensor according to any one of claims 13 to 15 ,
A force sensor, wherein the detection element is constituted by a capacitive element having a displacement electrode provided on a measurement target surface and a fixed electrode provided on a counter reference surface. The force sensor according to claim 16 , wherein
A force sensor characterized in that an arc-shaped arm and an inner member are made of a conductive material, and a capacitive element is formed by using the surface of the arc-shaped arm or the inner member as a displacement electrode. The force sensor according to claim 16 , wherein
A force sensor characterized in that a capacitive element is formed by forming a displacement electrode on the surface of an arc-shaped arm or an inner member via an insulating layer. The force sensor according to any one of claims 1 to 5,
n = 2, the inner member and the outer member are connected by the first arcuate arm and the second arcuate arm,
An XY plane or a predetermined plane parallel to the XY plane is defined as an arrangement plane, and on this arrangement plane, a first inner connection point, a second inner connection point, a first outer connection point, and a second outer connection Dots are placed,
The first inner connection point is arranged on or near the projection image of the negative area of the Y axis on the arrangement plane, and the second inner connection point is the projection image of the positive area of the Y axis on the arrangement plane. The first outer connection point is arranged on or near the projection image of the positive region of the Y axis on the arrangement plane, and the second outer connection point is arranged on the arrangement plane. Arranged on or near the projected image of the negative region of the Y axis,
When the rotation direction in which the right screw is advanced in the Z-axis positive direction is defined as a counterclockwise direction and the rotation direction in which the right screw is advanced in the Z-axis negative direction is defined as a clockwise direction, the first arcuate arm is the first inner side. A second arcuate arm extends from the second inner connection point to the first outer connection point in a selection direction of either a left-handed direction or a right-handed direction. A force sensor that extends in the selection direction toward the outer connection point of the two. The force sensor according to claim 19 ,
Make sure that the centerline of each arcuate arm is on the placement plane,
On the XY plane, a W1 axis obtained by rotating the X axis by 45 ° counterclockwise and a W2 axis obtained by rotating the Y axis by 45 ° counterclockwise are defined, and the W1 axis on the placement plane is defined. A first measurement point is defined at the intersection of the projected image of the positive region and the center line of the arcuate arm, and a second measurement point is defined at the intersection of the projected image of the negative region of the W1 axis on the placement plane and the centerline of the arcuate arm. The third measurement point is defined at the intersection of the projected image of the positive region of the W2 axis on the placement plane and the center line of the arcuate arm, and the negative of the W2 axis on the placement plane is defined. When a fourth measurement point is defined at the intersection of the projected image of the region and the center line of the arcuate arm,
A force sensor, wherein the detection element detects elastic deformation of each arcuate arm by electrically detecting displacement of the first to fourth measurement points. The force sensor according to claim 20 ,
A first capacitive element and a second capacitive element arranged in the vicinity of the first measurement point; a third capacitive element and a fourth capacitive element arranged in the vicinity of the second measurement point; A fifth capacitive element and a sixth capacitive element disposed in the vicinity of the third measurement point; and a seventh capacitive element and an eighth capacitive element disposed in the vicinity of the fourth measurement point. And
The first capacitive element is disposed in the vicinity of the first measurement point outside the arc-shaped arm and fixed to the inner member or the outer member, and the first fixed electrode on the surface of the arc-shaped arm. And a first displacement electrode formed in a region opposite to
The second capacitive element includes a second fixed electrode disposed in the vicinity of the first measurement point inside the arcuate arm and fixed to the inner member or the outer member, and the second fixed electrode on the surface of the arcuate arm. And a second displacement electrode formed in a region opposite to
The third capacitive element is disposed in the vicinity of the second measurement point inside the arc-shaped arm and fixed to the inner member or the outer member, and the third fixed electrode on the surface of the arc-shaped arm. And a third displacement electrode formed in a region opposite to
The fourth capacitive element includes a fourth fixed electrode disposed near the second measurement point outside the arc-shaped arm and fixed to the inner member or the outer member, and the fourth fixed electrode on the surface of the arc-shaped arm. And a fourth displacement electrode formed in a region opposite to
The fifth capacitive element is disposed in the vicinity of the third measurement point outside the arc-shaped arm and fixed to the inner member or the outer member, and the fifth fixed electrode on the surface of the arc-shaped arm. And a fifth displacement electrode formed in a region opposite to
The sixth capacitive element is disposed in the vicinity of the third measurement point inside the arc-shaped arm and fixed to the inner member or the outer member, and the sixth fixed electrode on the surface of the arc-shaped arm. And a sixth displacement electrode formed in a region opposite to
The seventh capacitive element is disposed in the vicinity of the fourth measurement point inside the arc-shaped arm and fixed to the inner member or the outer member, and the seventh fixed electrode on the surface of the arc-shaped arm. And a seventh displacement electrode formed in a region opposite to
The eighth capacitive element is disposed in the vicinity of the fourth measurement point outside the arcuate arm and fixed to the inner member or the outer member, and the eighth fixed electrode on the surface of the arcuate arm. And an eighth displacement electrode formed in a region opposite to
Based on the detection result of the detection element, when the detection circuit fixes one of the inner member and the outer member, the force Fx in the X-axis direction, the force Fy in the Y-axis direction, and the Z-axis rotation A force sensor that outputs a detected value of the moment Mz. The force sensor according to claim 21 , wherein
In addition to the first to fourth measurement points, further, fifth to eighth measurement points are additionally defined at predetermined positions of the arc-shaped arm or the inner member, and the fifth measurement point is placed on the arrangement plane. The sixth measurement point is arranged on the projection image of the positive region of the X axis or in the vicinity thereof, and the sixth measurement point is arranged on the projection image of the negative region of the X axis on the arrangement plane or in the vicinity thereof. The point is arranged on the projection image of the positive area of the Y axis on the arrangement plane or a position near it, and the eighth measurement point is on the projection image of the negative area of the Y axis on the arrangement plane or a position near it. To be placed in
The detection element includes a ninth capacitive element disposed in the vicinity of the fifth measurement point, a tenth capacitive element disposed in the vicinity of the sixth measurement point, and an eleventh element disposed in the vicinity of the seventh measurement point. And a twelfth capacitive element disposed in the vicinity of the eighth measurement point,
When the Z axis is the vertical axis,
The ninth capacitive element is disposed in the vicinity of the fifth measurement point below the arcuate arm or the inner member and fixed to the outer member, and the ninth capacitor element on the lower surface of the arcuate arm or the inner member. A ninth displacement electrode formed in a region facing the fixed electrode of
The tenth capacitive element is disposed in the vicinity of the sixth measurement point below the arcuate arm or the inner member and fixed to the outer member, and the tenth electrode on the lower surface of the arcuate arm or the inner member. A tenth displacement electrode formed in a region facing the fixed electrode of
The eleventh capacitive element is arranged in the vicinity of the seventh measurement point below the arcuate arm or the inner member and fixed to the outer member, and the eleventh electrode on the lower surface of the arcuate arm or the inner member. And an eleventh displacement electrode formed in a region facing the fixed electrode of
The twelfth capacitive element is arranged in the vicinity of the eighth measurement point below the arcuate arm or the inner member and fixed to the outer member, and the twelfth electrode on the lower surface of the arcuate arm or the inner member. And a twelfth displacement electrode formed in a region facing the fixed electrode of
In a state where one of the inner member and the outer member is fixed based on the detection result of the detection element, the detection circuit acts on the other in the X-axis direction force Fx, the Y-axis direction force Fy, and the Z-axis direction. A force sensor that outputs detected values of the force Fz, the moment Mx about the X axis, the moment My about the Y axis, and the moment Mz about the Z axis. The force sensor according to claim 22 , wherein
A support substrate disposed below the m-th basic structure;
The support substrate has a bottom plate portion facing the m-th basic structure, and an edge peripheral portion protruding upward from the periphery of the bottom plate portion,
The lower surface of the outer member of the m-th basic structure is fixed to the upper surface of the peripheral edge portion, and a cavity is formed between the lower surface of the inner member of the m-th basic structure and the upper surface of the bottom plate portion. Is formed, and the laminated inner member is supported by an arcuate arm so as to be displaceable in the surrounding space including the cavity,
A force sensor, wherein the first to twelfth fixed electrodes are fixed to the upper surface of the bottom plate portion. The force sensor according to claim 22 or 23 ,
A first arcuate arm extends counterclockwise from the first inner connection point toward the first outer connection point, and a second arcuate arm extends from the second inner connection point to the second outer connection point. It extends in the counterclockwise direction,
The detection circuit sets the capacitance value of the first capacitance element to C1, the capacitance value of the second capacitance element to C2, the capacitance value of the third capacitance element to C3, and the capacitance value of the fourth capacitance element. The capacitance value is C4, the capacitance value of the fifth capacitance element is C5, the capacitance value of the sixth capacitance element is C6, the capacitance value of the seventh capacitance element is C7, and the eighth capacitance element. The capacitance value of C9, the capacitance value of the ninth capacitance element C9, the capacitance value of the tenth capacitance element C10, the capacitance value of the eleventh capacitance element C11, When the capacitance value of the capacitive element is C12,
Fx = + C1-C2 + C3-C4-C5 + C6-C7 + C8
Fy = + C1-C2 + C3-C4 + C5-C6 + C7-C8
Fz =-(C9 + C10 + C11 + C12)
Mx = −C11 + C12
My = + C9-C10
Mz = + C1-C2-C3 + C4 + C5-C6-C7 + C8
Based on the following formula, the detection of the force Fx in the X-axis direction, the force Fy in the Y-axis direction, the force Fz in the Z-axis direction, the moment Mx around the X-axis, the moment My around the Y-axis, and the moment Mz around the Z-axis A force sensor that outputs a value. The force sensor according to claim 22 or 23 ,
A first arcuate arm extends clockwise from the first inner connection point toward the first outer connection point, and a second arcuate arm extends from the second inner connection point to the second outer connection point. It extends in the clockwise direction,
The detection circuit sets the capacitance value of the first capacitance element to C1, the capacitance value of the second capacitance element to C2, the capacitance value of the third capacitance element to C3, and the capacitance value of the fourth capacitance element. The capacitance value is C4, the capacitance value of the fifth capacitance element is C5, the capacitance value of the sixth capacitance element is C6, the capacitance value of the seventh capacitance element is C7, and the eighth capacitance element. The capacitance value of C9, the capacitance value of the ninth capacitance element C9, the capacitance value of the tenth capacitance element C10, the capacitance value of the eleventh capacitance element C11, When the capacitance value of the capacitive element is C12,
Fx = + C1-C2 + C3-C4-C5 + C6-C7 + C8
Fy = + C1-C2 + C3-C4 + C5-C6 + C7-C8
Fz =-(C9 + C10 + C11 + C12)
Mx = −C11 + C12
My = + C9-C10
Mz = -C1 + C2 + C3-C4-C5 + C6 + C7-C8
Based on the following formula, the detection of the force Fx in the X-axis direction, the force Fy in the Y-axis direction, the force Fz in the Z-axis direction, the moment Mx around the X-axis, the moment My around the Y-axis, and the moment Mz around the Z-axis A force sensor that outputs a value. A force sensor for detecting a force or a moment related to at least one of a force in each coordinate axis direction and a moment around each coordinate axis in an XYZ three-dimensional orthogonal coordinate system,
An inner member disposed on the Z-axis of the XYZ three-dimensional orthogonal coordinate system;
An outer member disposed so as to surround the Z axis, and containing the inner member therein;
It plays the role of connecting the inner member and the outer member, has the property of causing elastic deformation at least in part by the action of the force or moment to be detected, and so as to partially surround the inner member Two arcuate arms arranged;
Two sets of basic structures having
A detection element for electrically detecting elastic deformation of the arc-shaped arms of the two sets of basic structures;
Based on the detection result of the detection element, in a state where one of the inner members of the two sets of basic structures and the outer member of the two sets of basic structures is fixed, A detection circuit that outputs a detection value of a moment around a predetermined coordinate axis;
With
The two sets of basic structures are arranged so as to be adjacent in the vertical direction with the Z axis as a vertical axis, and in both cases, the inner member and the outer member are connected by the first arc-shaped arm and the second arc-shaped arm. And when the predetermined plane parallel to the XY plane is defined as an arrangement plane, the inner end of the first arcuate arm is connected to a first inner connection point on the inner member, The outer end of the first arcuate arm is connected to a first outer connection point on the outer member, and the inner end of the second arcuate arm is connected to a second inner connection point on the inner member. The outer end of the second arcuate arm is connected to a second outer connection point on the outer member, and the first inner connection point and the second inner connection point are different on the arrangement plane. The first outer connection point and the second outer connection point. It is referred to as the upper base structure one disposed above of the different positions in a point that the two sets of basic structures on the said arrangement plane, called the other disposed below the lower base structure In this case, an inner intermediate member is provided between the lower surface of the inner member of the upper basic structure and the upper surface of the inner member of the lower basic structure, and the outer member of the upper basic structure. An outer intermediate member is provided between the lower surface of the lower basic structure and the upper surface of the outer member of the lower basic structure.
The inner member of the upper basic structure, the inner intermediate member, and the inner member of the lower basic structure are connected to each other, and the whole functions as a laminated inner member, and the outer member of the upper basic structure, The outer intermediate member and the outer member of the lower basic structure are connected to each other, and the whole functions as a laminated outer member,
The detecting element, the upper base structure and electrically detecting the elastic deformation of the arcuate arms of the lower base structure, the detection circuit based on the detection result of the detecting element, the laminated inner member and the A force sensor that outputs a detected value of a force in a predetermined coordinate axis direction or a moment around a predetermined coordinate axis applied to the other in a state where one of the laminated outer members is fixed. The force sensor according to claim 26 , wherein
The upper basic structure and the lower basic structure are geometrically congruent structures, both of which are arranged with the Z axis as a common central axis, and the lower basic structure is the upper basic structure Z A force sensor characterized in that the force sensor is disposed in a direction rotated by 90 ° about an axis. The force sensor according to claim 27 , wherein
As the upper basic structure,
The first inner connection point is arranged on or near the projection image of the negative area of the Y axis on the arrangement plane, and the second inner connection point is the projection image of the positive area of the Y axis on the arrangement plane. The first outer connection point is arranged on or near the projection image of the positive region of the Y axis on the arrangement plane, and the second outer connection point is arranged on the arrangement plane. Arranged on or near the projected image of the negative region of the Y axis,
When the rotation direction in which the right screw is advanced in the Z-axis positive direction is defined as a counterclockwise direction and the rotation direction in which the right screw is advanced in the Z-axis negative direction is defined as a clockwise direction, the first arcuate arm is the first inner side. A second arcuate arm extends from the second inner connection point to the first outer connection point in a selection direction of either a left-handed direction or a right-handed direction. Using the structure extending in the selection direction toward the outer connection point of 2;
As the lower basic structure,
A force sensor using a structure in which a structure geometrically congruent with the upper basic structure is arranged in a direction rotated by 90 ° about a Z axis as a rotation axis. The force sensor according to claim 26 , wherein
The upper basic structure and the lower basic structure are geometrically congruent structures, both of which are arranged with the Z axis as a common central axis, and the lower basic structure is the upper basic structure X The force sensor is arranged in a direction rotated by 180 ° with the axis or Y axis as the rotation axis and further rotated by 90 ° with the Z axis as the rotation axis. The force sensor according to claim 29 ,
As the upper basic structure,
The first inner connection point is arranged on or near the projection image of the negative area of the Y axis on the arrangement plane, and the second inner connection point is the projection image of the positive area of the Y axis on the arrangement plane. The first outer connection point is arranged on or near the projection image of the positive region of the Y axis on the arrangement plane, and the second outer connection point is arranged on the arrangement plane. Arranged on or near the projected image of the negative region of the Y axis,
When the rotation direction in which the right screw is advanced in the Z-axis positive direction is defined as a counterclockwise direction and the rotation direction in which the right screw is advanced in the Z-axis negative direction is defined as a clockwise direction, the first arcuate arm is the first inner side. A second arcuate arm extends from the second inner connection point to the first outer connection point in a selection direction of either a left-handed direction or a right-handed direction. Using the structure extending in the selection direction toward the outer connection point of 2;
As the lower basic structure,
A structure in which the structure that is geometrically congruent with the upper basic structure is rotated 180 ° with the X-axis or Y-axis as the rotation axis, and is further rotated 90 ° with the Z-axis as the rotation axis Force sensor characterized by using The force sensor according to claim 28 or 30 ,
For each of the upper basic structure and the lower basic structure, the center line of each arc-shaped arm is positioned on the arrangement plane,
For the upper basic structure, a first measurement point is defined at the intersection of the projected image of the positive region of the X axis on the placement plane and the center line of the arc arm, and the negative region of the X axis is projected on the placement plane. Define a second measurement point at the intersection of the image and the center line of the arcuate arm,
For the lower basic structure, a third measurement point is defined at the intersection of the projected image of the positive area of the Y axis on the placement plane and the center line of the arcuate arm, and the negative area of the Y axis is projected on the placement plane. Define a fourth measurement point at the intersection of the image and the centerline of the arcuate arm,
A force sensor, wherein the detection element detects elastic deformation of each arcuate arm by electrically detecting displacement of the first to fourth measurement points. The force sensor according to claim 31 , wherein
The detection element includes a first capacitive element disposed near the first measurement point, a second capacitive element disposed near the second measurement point, and a third capacitive element disposed near the third measurement point. And a fourth capacitive element disposed in the vicinity of the fourth measurement point,
The first capacitive element is disposed in the vicinity of the first measurement point outside or inside the arc-shaped arm and fixed to the laminated inner member or the laminated outer member, and the first capacitive element on the surface of the arc-shaped arm. A first displacement electrode formed in a region facing one fixed electrode,
The second capacitive element is disposed in the vicinity of the second measurement point outside or inside the arcuate arm and fixed to the laminated inner member or the laminated outer member, and the second capacitive element on the surface of the arcuate arm. A second displacement electrode formed in a region facing the two fixed electrodes,
The third capacitive element is disposed near the third measurement point outside or inside the arc-shaped arm and fixed to the laminated inner member or the laminated outer member, and the third capacitive element on the surface of the arc-shaped arm. A third displacement electrode formed in a region facing the three fixed electrodes,
The fourth capacitive element is disposed in the vicinity of the fourth measurement point outside or inside the arcuate arm and fixed to the laminated inner member or laminated outer member, and the fourth capacitor element on the surface of the arcuate arm. A fourth displacement electrode formed in a region facing the four fixed electrodes,
Based on the detection result of the detection element, when the detection circuit fixes one of the laminated inner member and the laminated outer member, the force Fx in the X-axis direction, the force Fy in the Y-axis direction, and the Z-axis rotation A force sensor that outputs a detected value of the moment Mz. The force sensor according to claim 32 , wherein
In addition to the first to fourth measurement points, the fifth to eighth measurement points are defined at predetermined positions of the arc-shaped arm or the inner member of the lower basic structure, and the fifth measurement point is the lower basic structure. The sixth measurement point is located on the projected image of the negative region of the X-axis on the plane of placement of the lower basic structure. Alternatively, the seventh measurement point is arranged on the projection image of the positive region of the Y axis on the arrangement plane of the lower basic structure or in the vicinity thereof, and the eighth measurement point is arranged on the lower stage. It is arranged on the projection image of the negative area of the Y axis on the arrangement plane of the basic structure or in the vicinity thereof,
The detection element includes a fifth capacitive element disposed in the vicinity of the fifth measurement point, a sixth capacitive element disposed in the vicinity of the sixth measurement point, and a seventh capacitive element disposed in the vicinity of the seventh measurement point. And an eighth capacitive element disposed in the vicinity of the eighth measurement point,
The fifth capacitive element includes a fifth fixed electrode disposed in the vicinity of the fifth measurement point below the arc-shaped arm or inner member of the lower basic structure, and fixed to the outer member of the lower basic structure; A fifth displacement electrode formed in a region of the arcuate arm of the basic structure or the lower surface of the inner member facing the fifth fixed electrode, and
The sixth capacitive element includes a sixth fixed electrode disposed in the vicinity of the sixth measurement point below the arc-shaped arm or inner member of the lower basic structure, and fixed to the outer member of the lower basic structure; A sixth displacement electrode formed in a region of the arcuate arm of the basic structure or the lower surface of the inner member facing the sixth fixed electrode, and
The seventh capacitive element includes a seventh fixed electrode disposed in the vicinity of the seventh measurement point below the arc-shaped arm or inner member of the lower basic structure, and fixed to the outer member of the lower basic structure; A seventh displacement electrode formed in a region of the arcuate arm of the basic structure or the lower surface of the inner member facing the seventh fixed electrode, and
The eighth capacitive element includes an eighth fixed electrode disposed in the vicinity of the eighth measurement point below the arc-shaped arm or inner member of the lower basic structure, and fixed to the outer member of the lower basic structure; An arcuate arm of the basic structure or an eighth displacement electrode formed in a region facing the eighth fixed electrode on the lower surface of the inner member;
In a state in which the detection circuit fixes one of the laminated inner member and the laminated outer member based on the detection result of the detection element, the force Fx in the X-axis direction, the force Fy in the Y-axis direction, and the Z-axis direction applied to the other A force sensor that outputs detected values of the force Fz, the moment Mx about the X axis, the moment My about the Y axis, and the moment Mz about the Z axis. The force sensor according to claim 33 ,
It further includes a support substrate disposed below the lower basic structure,
The support substrate has a bottom plate portion facing the lower basic structure, and an edge peripheral portion protruding upward from the periphery of the bottom plate portion,
The lower surface of the outer member of the lower basic structure is fixed to the upper surface of the peripheral edge, and a cavity is formed between the lower surface of the inner member of the lower basic structure and the upper surface of the bottom plate portion. The laminated inner member is supported by an arcuate arm so as to be displaceable in the surrounding space including the cavity,
A force sensor, wherein the first to eighth fixed electrodes are fixed to the upper surface of the bottom plate portion.

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