Patent Publication Number: US-2023152172-A1

Title: Torque sensor

Description:
FIELD 
     The present invention relates to a torque sensor. 
     BACKGROUND 
     Heretofore, there has been known a torque sensor that outputs, as an electric signal, moment (torque) acting about a predetermined rotation axis (e.g., see Patent Literature 1). This torque sensor is widely utilized for torque control of various robots including industrial robots, such as collaborative robots, life support robots, medical robots, and service robots. Thus a high-precision, high-sensitivity, and low-price torque sensor is required. 
     For example, a general torque sensor includes a circular ring-shaped force receiving body, a circular ring-shaped strain body, and a circular ring-shaped support body. The strain body is disposed inside the force receiving body, and the support body is disposed inside the strain body. The force receiving body, the strain body, and the support body are disposed on an XY plane, and the strain body is connected to each of the force receiving body and the support body. When moment about a Z-axis acts on the force receiving body, the strain body is elastically deformed radially. This elastic deformation of the strain body is detected by an electrostatic capacitive element having a fixed electrode and a displacement electrode. The displacement electrode is mounted on the outer peripheral surface of the strain body, and the fixed electrode is mounted on the inner peripheral surface of the force receiving body so as to face the displacement electrode. The fixed electrode may be mounted on the outer peripheral surface of the support body, in which case the displacement electrode is mounted on the inner peripheral surface of the strain body. 
     In the torque sensor having such a configuration, the displacement electrode and the fixed electrode are disposed so that the facing surfaces are perpendicular to the XY plane. In this case, the alignment of the displacement electrode and the fixed electrode becomes difficult, and the efficiency of manufacturing the torque sensor can deteriorate. 
     Patent Literature WO 2013/04803 A1 
     SUMMARY 
     The present invention has been made in view of such points, and is directed to provide a torque sensor for which the efficiency of manufacture is improved. 
     The present invention provides a torque sensor that detects moment about a Z-axis in an XYZ three-dimensional coordinate system, including: 
     a first structure formed around the Z-axis; 
     a second structure formed around the Z-axis; 
     a strain body provided between the first structure and the second structure, the strain body connecting the first structure and the second structure, and producing elastic deformation by the action of the moment; 
     two first structure Y-axis connecting portions that connect the first structure and the strain body; 
     two second structure X-axis connecting portions that connect the strain body and the second structure; 
     a detection element; and 
     a detection circuit that outputs an electric signal indicating the moment, based on a detection result of the detection element, wherein 
     the first structure Y-axis connecting portions are disposed on a positive side and a negative side of a Y-axis relative to the strain body, 
     the second structure X-axis connecting portions are disposed on a positive side and a negative side of an X-axis relative to the second structure, 
     the strain body includes four deformable bodies each including a displacement portion that is displaced in a Z-axis direction by elastic deformation, 
     the deformable bodies are respectively disposed in a first quadrant, a second quadrant, a third quadrant, and a fourth quadrant, and 
     the detection element includes a capacitive element that detects a change in capacitance value by a displacement of the displacement portion of each of the deformable bodies in the Z-axis direction. 
     In addition, in the torque sensor described above, 
     the second structure may be disposed inside the first structure when seen along the Z-axis. 
     Further, in the torque sensor described above, 
     the first structure Y-axis connecting portion may extend along the Y-axis and the Z-axis, 
     the dimension of the first structure Y-axis connecting portion in the Z-axis direction may be greater than the dimension of the first structure Y-axis connecting portion in the Y-axis direction, 
     the second structure X-axis connecting portion may extend along the X-axis and the Z-axis, and 
     the dimension of the second structure X-axis connecting portion in the Z-axis direction may be greater than the dimension of the second structure X-axis connecting portion in the X-axis direction. 
     Further, the torque sensor described above may further include: 
     two first structure X-axis connecting portions that connect the first structure and the second structure; and 
     two second structure Y-axis connecting portions that connect the strain body and the second structure, wherein 
     when seen along the Z-axis, the first structure X-axis connecting portions may be disposed on a positive side and a negative side of the X-axis relative to the strain body, and the second structure Y-axis connecting portions may be disposed on a positive side and a negative side of the Y-axis relative to the second structure, 
     the first structure X-axis connecting portion may extend along the X-axis, and 
     the second structure Y-axis connecting portion may extend along the Y-axis. 
     Further, in the torque sensor described above, 
     the first structure X-axis connecting portion and the second structure Y-axis connecting portion may extend along the Z-axis, 
     the dimension of the first structure X-axis connecting portion in the Z-axis direction may be greater than the dimension of the first structure X-axis connecting portion in the X-axis direction, and 
     the dimension of the second structure Y-axis connecting portion in the Z-axis direction may be greater than the dimension of the second structure Y-axis connecting portion in the Y-axis direction. 
     Further, in the torque sensor described above, 
     the dimension of the first structure X-axis connecting portion in the Y-axis direction may be smaller than the dimension of the first structure Y-axis connecting portion in the X-axis direction, and 
     the dimension of the second structure Y-axis connecting portion in the X-axis direction may be smaller than the dimension of the second structure X-axis connecting portion in the Y-axis direction. 
     Further, in the torque sensor described above, 
     the strain body may be formed into a circular ring shape when seen along the Z-axis. 
     Further; in the torque sensor described above, it may be that 
     the strain body and the second structure are not connected at a position of the strain body where the first structure Y-axis connecting portion is connected, and 
     the first structure and the strain body are not connected at a position of the strain body where the second structure X-axis connecting portion is connected. 
     Further, in the torque sensor described above, 
     the dimension of the first structure X-axis connecting portion in the X-axis direction may be greater than the dimension of the first structure Y-axis connecting portion in the Y-axis direction, and 
     the dimension of the second structure Y-axis connecting portion in the Y-axis direction may be greater than the dimension of the second structure X-axis connecting portion in the X-axis direction. 
     Further, in the torque sensor described above, 
     the strain body may be formed into an elliptical ring shape so as to have a long axis along the Y-axis and a short axis along the X-axis, when seen along the Z-axis. 
     Further, in the torque sensor described above, 
     the first structure Y-axis connecting portion may be formed at a connection position between the first structure and the strain body, and 
     the second structure X-axis connecting portion may be formed at a connection position between the strain body and the second structure. 
     Further, in the torque sensor described above, 
     the outer peripheral surface of the strain body may be formed into an elliptical shape so as to have a long axis along the Y-axis and a short axis along the X-axis, when seen along the Z-axis. 
     Further, in the torque sensor described above, 
     the outer peripheral surface of the second structure may be formed into an elliptical shape so as to have a long axis along the X-axis and a short axis along the Y-axis, when seen along the Z-axis. 
     Further, the torque sensor described above may further include: 
     two first structure X-axis connecting portions that connect the first structure and the strain body; and 
     two second structure Y-axis connecting portions that connect the strain body and the second structure, wherein 
     when seen along the Z-axis, the first structure X-axis connecting portions may be disposed on a positive side and a negative side of the X-axis relative to the strain body, and the second structure Y-axis connecting portions may be disposed on a positive side and a negative side of the Y-axis relative to the second structure, 
     the first structure X-axis connecting portion may extend along the X-axis, and 
     the second structure Y-axis connecting portion may extend along the Y-axis. 
     Further, in the torque sensor described above, 
     the dimension of the first structure X-axis connecting portion in the Y-axis direction may be smaller than the dimension of the first structure Y-axis connecting portion in the X-axis direction, and 
     the dimension of the second structure Y-axis connecting portion in the X-axis direction may be smaller than the dimension of the second structure X-axis connecting portion in the Y-axis direction. 
     Further, in the torque sensor described above, it may be that 
     the strain body and the second structure are not connected at a position of the strain body where the first structure Y-axis connecting portion is connected, and 
     the first structure and the strain body are not connected at a position of the strain body where the second structure X-axis connecting portion is connected. 
     Further, in the torque sensor described above, 
     the second structure may be disposed on a negative side of the Z-axis relative to the strain body. 
     Further, in the torque sensor described above, 
     the strain body may be disposed on a negative side of the Z-axis relative to the first structure. 
     According to the present invention, manufacturing efficiency can be improved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWING 
         FIG.  1    is a perspective view illustrating one example of a robot to which a torque sensor according to a first embodiment is applied. 
         FIG.  2    is a plan view illustrating the torque sensor according to the first embodiment. 
         FIG.  3    is a sectional view along the line A-A in  FIG.  2   . 
         FIG.  4    is a perspective view illustrating the torque sensor in  FIG.  2   . 
         FIG.  5    is an enlarged plan view illustrating a deformable body in  FIG.  2   . 
         FIG.  6    is a sectional view illustrating the deform deformable body and a capacitive element in  FIG.  2   , 
         FIG.  7    is perspective view illustrating each connecting portion in  FIG.  2   . 
         FIG.  8    is a plan view illustrating a case where moment about a Z-axis acts on the torque sensor in  FIG.  2   . 
         FIG.  9    is a sectional view illustrating how the capacitance value of the capacitive element in  FIG.  6    decreases. 
         FIG.  10    is a sectional view illustrating how the capacitance value of the capacitive element in  FIG.  6    increases. 
         FIG.  11    is a plan view illustrating a modification of the torque sensor in  FIG.  2   . 
         FIG.  12    is a plan view illustrating another r modification of the torque sensor in  FIG.  2   . 
         FIG.  13 A  is a sectional view illustrating a modification of the deformable body in  FIG.  6   . 
         FIG.  13 B  is a sectional view illustrating another modification of the deformable body in  FIG.  6   . 
         FIG.  14    is a sectional view illustrating a modification of the torque sensor in  FIG.  3   . 
         FIG.  15    is a plan view illustrating a torque sensor according to a second embodiment. 
         FIG.  16    is a plan view illustrating a modification of the torque sensor in  FIG.  15   . 
         FIG.  17    is a plan view illustrating a torque sensor according to a third embodiment. 
         FIG.  18    is a plan view illustrating a modification of the torque sensor in  FIG.  17   . 
         FIG.  19    is a sectional view illustrating a torque sensor according to a fourth embodiment. 
         FIG.  20    is a sectional view along the line B-B in  FIG.  19   . 
         FIG.  21    is a sectional view along the line C-C in  FIG.  19   . 
         FIG.  22    is a sectional view illustrating a modification of the torque sensor in  FIG.  19   . 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of the present invention are described with reference to the drawings. In addition, in the drawings accompanying the present specification, scale, a lengthwise and crosswise dimensional ratio, and others are suitably modified and exaggerated from real ones for convenience of illustration and ease of understanding. 
     In addition, terms such as “parallel”, “orthogonal”, and “equal” used in the present specification to specify shapes, geometrical conditions, physical properties, and their degrees, dimensions, values of physical properties, and others are not restricted to strict meanings, and are interpreted including the range of such a degree that similar function can be expected. 
     First Embodiment 
     First, a torque sensor according to a first embodiment of the present invention is described by use of  FIGS.  1  to  14   . 
     Before describing the torque sensor according to the present embodiment, an example of applying the torque sensor to a robot is described with reference to  FIG.  1   .  FIG.  1    is a perspective view illustrating one example of a robot to which the torque sensor according to the present embodiment is applied. 
     As illustrated in  FIG.  1   , an industrial robot  1000  includes a robot main body  1100 , an end effector  1200 , an electric cable  1300 , a control unit  1400 , and a torque sensor  1 . The robot main body  1100  includes an arm portion of the robot. The torque sensor  1  is provided between the robot main body  1100  and the end effector  1200 . 
     The electric cable  1300  extends inside the robot main body  1100 . This electric cable  1300  is connected to a connector (not illustrated) of the torque sensor  1 . 
     In addition, the control unit  1400  is disposed inside the robot main body  1100  in  FIG.  1   , but it may be disposed in another place (e.g., a control board outside the robot). Moreover, an aspect of attaching the torque sensor  1  to the robot is not limited to the one illustrated in  FIG.  1   . 
     The torque sensor  1  detects moment acting on the end effector  1200  that functions as a gripper, An electric signal indicating the detected moment is transmitted to the control unit  1400  of the industrial robot  1000  via the electric cable  1300 . The control unit  1400  controls the operations of the robot main body  1100  and the end effector  1200 , based on the received electric signal. Moreover, a torque sensor may be provided in a non-illustrated joint of the robot main body  1100 . In this case, the torque sensor may be disposed parallel to a decelerator coupled to a drive unit for driving a joint. 
     In addition, the torque sensor  1  is not limited to an industrial robot, and it can be applied to various robots such as a collaborative robot, a life support robot, a medical robot, and a service robot. 
     The torque sensor according to the embodiment of the present invention is described below with reference to  FIGS.  2  to  7   ,  FIG.  2    is a plan view illustrating the torque sensor in the first embodiment.  FIG.  3    is a sectional view along the line A-A in  FIG.  2   .  FIG.  4    is a perspective view illustrating the torque sensor in  FIG.  2   .  FIG.  5    is an enlarged plan view illustrating a deformable body in  FIG.  2   .  FIG.  6    is a sectional view illustrating the deformable body and a capacitive element in  FIG.  2   .  FIG.  7    is a perspective view illustrating each connecting portion in  FIG.  2   . 
     The torque sensor  1  has a function of detecting moment (torque) acting about a predetermined rotation axis, and outputting the detected moment as an electric signal. However, without being limited thereto, the torque sensor  1  may have a function of additionally outputting moment acting about another rotation axis as an electric signal. Moreover, the torque sensor  1  may be configured to additionally output force in a predetermined direction as an electric signal. 
     In the present embodiment, the torque sensor  1  that detects moment about a Z-axis in an XYZ three-dimensional coordinate system is described. In a state of the description given below, a Z-axis direction is an up-down direction, and the torque sensor  1  is disposed so that a force receiving body  10 , a support body  20 , and a strain body  30  are disposed on an XY plane. The torque sensor  1  according to the present embodiment is not limited to being used in a posture in which the Z-axis direction is the up-down direction. 
     As illustrated in  FIGS.  2  to  4   , the torque sensor  1  includes the force receiving body  10 , the support body  20 , the strain body  30 , a force receiving body Y-axis connecting portion  41 , a support body X-axis connecting portion  51 , a detection element  60 , and a detection circuit  70 . Each component is described in more detail below. The force receiving body  10  is one example of a first structure, and the support body  20  is one example of a second structure. The force receiving body Y-axis connecting portion  41  is one example of a first structure Y-axis connecting portion, and the support body X-axis connecting portion  51  is one example of a second structure X-axis connecting portion. 
     The force receiving body  10  is formed about the Z-axis. The force receiving body  10  may be formed into a flat shape. The force receiving body  10  may be formed into a circular ring shape when seen along the Z-axis. 
     The force receiving body  10  receives action of moment to be detected. The force receiving body  10  moves relative to the support body  20  by receiving this action. As far as the example of  FIG.  1    described above is concerned, the force receiving body  10  is fixed to the end effector  1200 , and receives moment from the end effector  1200 . As illustrated in  FIG.  3   , the force receiving body  10  includes a fitting surface  10   a  fixed to the end effector  1200 . The fitting surface  10   a  is disposed on a Z-axis positive side of the force receiving body  10 , and is equivalent to the upper surface (surface on the Z-axis positive side) of the force receiving body  10 . The fitting surface  10   a  may be disposed more on the Z-axis positive side than an upper surface  30   a  of the strain body  30  (strain body connecting portions  32   a  to  32   d  described later) and an upper surface  20   a  of the support body  20 . This can prevent interference between the end effector  1200  and the torque sensor  1  when the torque sensor  1  is fixed to the end effector  1200 . The upper surface  30   a  of the strain body  30  and the upper surface  20   a  of the support body  20  may be disposed at the same position in the Z-axis direction. The upper surface  30   a  of the strain body  30  and the upper surface of each of connecting portions  41 ,  42 ,  51 , and  52  described later may be disposed at the same position in the Z-axis direction. 
     As illustrated in  FIGS.  2  and  4   , the support body  20  is formed about the Z-axis. The support body  20  may be formed into a flat shape. The support body  20  may be formed into a circular ring shape when seen along the Z-axis. A sensor opening  2  of the torque sensor  1  is formed inside the support body  20 . A cable and a tube used in the robot is passed through the sensor opening  2  in some cases. When seen along the Z-axis, the support body  20  is disposed inside the force receiving body  10 , and is apart from the force receiving body  10 . The support body  20  is disposed on the XY plane together with the force receiving body  10 , and may be formed concentrically with the force receiving body  10 . 
     The support body  20  supports the force receiving body  10 . As far as the example of  FIG.  1    described above is concerned, the support body  20  is fixed to the end of the robot main body  1100  (arm portion), and supported by the robot main body  1100 . As illustrated in  FIG.  3   , the support body  20  includes a fitting surface  20   b  fixed to the robot main body  1100 . The fitting surface  20   b  is disposed on a Z-axis negative side of the support body  20 , and is equivalent to the lower surface (surface on the Z-axis negative side) of the support body  20 . The fitting surface  20   b  may be disposed more on the Z-axis negative side than a lower surface  10   b  of the force receiving body  10  and a lower surface  30   b  of the strain body  30  (the strain body connecting portions  32   a  to  32   d  described later). Moreover, as will be described later, when an electrode support body  80  described later is provided on the lower surface  10   b  of the force receiving body  10 , the fitting surface  20   b  may be disposed more on the Z-axis negative side than a lower surface  80   a  of the electrode support body  80 . In this case, this can prevent interference between the robot main body  1100  and the torque sensor  1  when the torque sensor  1  is fixed to the robot main body  1100 . 
     As illustrated in  FIGS.  2  to  4   , the strain body  30  is provided between the force receiving body  10  and the support body  20 . In the present embodiment, the strain body  30  may be formed into a circular ring shape when seen along the Z-axis. When seen along the Z-axis, the strain body  30  is disposed inside the force receiving body  10 , and disposed outside the support body  20 . The strain body  30  is apart from the force receiving body  10 , and apart from the support body  20 . The strain body  30  may be formed concentrically with the force receiving body  10 , and formed concentrically with the support body  20 . The width (radial dimension) of the strain body  30  may be circumferentially constant. 
     The strain body  30  connects the force receiving body  10  and the support body  20 . The force receiving body  10  is supported by the support body  20  via the strain body  30 . The strain body  30  is configured to be elastically deformed when the force receiving body  10  receives the action of moment. 
     As illustrated in  FIGS.  2  and  4   , the strain body  30  includes four deformable bodies  31   a  to  31   d . Each of the deformable bodies  31   a  to  31   d  is configured to cause elastic deformation by the action of moment. The four deformable bodies  31   a  to  31   d  include the first deformable body  31   a  disposed in a first quadrant, the second deformable body  31   b  disposed in a second quadrant, the third deformable body  31   c  disposed in a third quadrant, and the fourth deformable body  31   d  disposed in a fourth quadrant. 
     The first deformable body  31   a  and the third deformable body  31   c  may be disposed on a line L 1  passing through the first quadrant and the third quadrant and being at 45° to an X-axis and a Y-axis. Each of later-described deformable portions  33  and  34  of the first deformable body  31   a  and the third deformable body  31   c  as well as a displacement portion  35  may be disposed parallel to the line L 1 . The second deformable body  31   b  and the fourth deformable body  31   d  may be disposed on a line L 2  passing through the second quadrant and the fourth quadrant and being at 45° to the X-axis and the Y-axis. Each of later-described deformable portions  33  and  34  of the second deformable body  31   b  and the fourth deformable body  31   d  as well as the displacement portion  35  may be disposed parallel to the line L 2 . The first deformable body  31   a  and the second deformable body  31   b  may be disposed symmetrically to the fourth deformable body  31   d  and the third deformable body  31   c  with respect to the X-axis. The first deformable body  31   a  and the fourth deformable body  31   d  may be disposed symmetrically to the second deformable body  31   b  and the third deformable body  31   c  with respect to the Y-axis. When seen along the Z-axis, each of the deformable bodies  31   a  to  31   d  may be disposed point-symmetrically with respect to an origin O. 
     The strain body  30  includes the four strain body connecting portions  32   a  to  32   d . Each of the strain body connecting portions  32   a  to  32   d  connects the corresponding two deformable bodies  31   a  to  31   d . The four strain body connecting portions  32   a  to  32   d  include the first strain body connecting portion  32   a , the second strain body connecting portion  32   b , the third strain body connecting portion  32   c , and the fourth strain body connecting portion  32   d . The first strain body connecting portion  32   a  connects the first deformable body  31   a  and the second deformable body  31   b . The second strain body connecting portion  32   b  connects the second deformable body  31   b  and the third deformable body  31   c . The third strain body connecting portion  32   c  connects the third deformable body  31   c  and the fourth deformable body  31   d . The fourth strain body connecting portion  32   d  connects the fourth deformable body  31   d  and the first deformable body  31   a.    
     As illustrated in  FIGS.  5  and  6   , in the present embodiment, each of the deformable bodies  31   a  to  31   d  includes the first deformable portion  33 , the second deformable portion  34 , and the displacement portion  35 . The first deformable portion  33  is connected to the corresponding strain body connecting portions  32   a  to  32   d , and the second deformable portion  34  is connected to the corresponding other strain body connecting portions  32   a  to  32   d . The displacement portion  35  is disposed between the first deformable portion  33  and the second deformable portion  34 , and the first deformable portion  33  and the second deformable portion  34  are connected to each other via the displacement portion  35 . 
     The first deformable portion  33  and the second deformable portion  34  are formed into a plate shape, and have smaller thicknesses than each of the strain body connecting portions  32   a  to  32   d  when radially seen. The first deformable portion  33  and the second deformable portion  34  each have a function as a leaf spring, and are easily elastically deformable. The displacement portion  35  is also formed into a plate shape, and has smaller thickness than each of the strain body connecting portions  32   a  to  32   d . The thickness of the first deformable portion  33 , the thickness of the second deformable portion  34 , and the thickness of the displacement portion  35  may be equal. Alternatively, the thickness of the displacement portion  35  may be greater than the thickness of the first deformable portion  33  and the thickness of the second deformable portion  34 . 
     The first deformable portion  33  extends downward toward the displacement portion  35  from an upper end of an end face  32   e  (see  FIG.  6   ) of each of the corresponding strain body connecting portions  32   a  to  32   d . For example, the first deformable portion  33  of the first deformable body  31   a  extends downward toward the displacement portion  35  from an upper end of the end face  32   e  of the fourth strain body connecting portion  32   d . When radially seen, the first deformable portion  33  is tilted relative to the Z-axis, and extends linearly. The second deformable portion  34  extends downward toward the displacement portion  35  from an upper end of the end face  32   e  of the corresponding strain body connecting portions  32   a  to  32   d . For example, the second deformable portion  34  of the first deformable body  31   a  extends downward toward the displacement portion  35  from an upper end of the end face  32   e  of the first strain body connecting portion  32   a . When radially seen, the second deformable portion  34  is tilted relative to the Z-axis, and extends linearly. 
     The displacement portion  35  is disposed perpendicularly to the Z-axis, i.e., along the XY plane. When radially seen, the displacement portion  35  is formed linearly along the XY plane. As illustrated in  FIG.  6   , a lower surface  35   a  of the displacement portion  35  may be disposed at a position more on the Z-axis positive side than the lower surface  30   b  of each of the strain body connecting portions  32   a  to  32   d  (the strain body  30 ). The displacement portion  35  is configured to be displaced in the Z-axis direction by the elastic deformation of the first deformable portion  33  and the second deformable portion  34 . 
     As illustrated in  FIG.  5   , the first deformable portion  33 , the second deformable portion  34 , and the displacement portion  35  are each formed into a curved shape when seen along the Z-axis. More specifically, the first deformable portion  33 , the second deformable portion  34 , and the displacement portion  35  constitute a part of the circular ring shape of the strain body  30 , and are formed into an arc shape. The first deformable portion  33 , the second deformable portion  34 , and the displacement portion  35  may be formed concentrically with the force receiving body  10  or the support body  20 . 
     As illustrated in  FIGS.  2  to  4   , the force receiving body Y-axis connecting portion  41  connects the force receiving body  10  and the strain body  30 . The force receiving body  10  and the strain body  30  are connected by the two force receiving body Y-axis connecting portions  41 . When seen along the Z-axis, the force receiving body Y-axis connecting portions  41  are disposed on the positive side of the Y-axis and the negative side of the Y-axis relative to the strain body  30 . In the present embodiment, one of the force receiving body Y-axis connecting portions  41  is disposed at a position on the positive side of the Y-axis relative to the strain body  30 . This force receiving body Y-axis connecting portion  41  connects the force receiving body  10  and the first strain body connecting portion  32   a . The other one of the force receiving body Y-axis connecting portions  41  is disposed at a position on the negative side of the Y-axis. This force receiving body Y-axis connecting portion  41  connects the force receiving body  10  and the third strain body connecting portion  32   c.    
     The force receiving body Y-axis connecting portion  41  according to the present embodiment is disposed on the Y-axis, and extends along the Y-axis. In the present embodiment, as illustrated in  FIG.  7   , the force receiving body Y-axis connecting portion  41  is formed into a rectangular shape along the X-axis, the Y-axis, and the Z-axis. The dimension (equivalent to Lz in  FIG.  7   ) of the force receiving body Y-axis connecting portion  41  in the Z-axis direction is greater than the dimension (Ply in  FIG.  2   ) of the force receiving body Y-axis connecting portion  41  in the Y-axis direction. 
     As illustrated in  FIGS.  2  to  4   , the support body X-axis connecting portion  51  connects the strain body  30  and the support body  20 . The strain body  30  and the support body  20  are connected by the two support body X-axis connecting portions  51 . When seen along the Z-axis, the support body X-axis connecting portions  51  are disposed on the positive side of the X-axis and the negative side of the X-axis relative to the support body  20 . In the present embodiment, one of the support body X-axis connecting portions  51  is disposed at a position on the positive side of the X-axis. This support body X-axis connecting portion  51  connects the support body  20  and the fourth strain body connecting portion  32   d . The other one of the support body X-axis connecting portions  51  is disposed at a position on the negative side of the X-axis. This support body X-axis connecting portion  51  connects the support body  20  and the second strain body connecting portion  32   b.    
     The support body X-axis connecting portion  51  according to the present embodiment is disposed on the X-axis, and extends along the X-axis. In the present embodiment, similar to the force receiving body Y-axis connecting portion  41 , the support body X-axis connecting portion  51  is formed into a rectangular shape along the X-axis, the Y-axis, and the Z-axis. The dimension (equivalent to Lz in  FIG.  7   ) of the support body X-axis connecting portion  51  in the Z-axis direction is greater than the dimension (Q 1   x  in  FIG.  2   ) of the support body X-axis connecting portion  51  in the X-axis direction. 
     As illustrated in  FIGS.  2  to  4   , the torque sensor  1  according to the present embodiment includes the force receiving body X-axis connecting portion  42  and the support body Y-axis connecting portion  52 . The force receiving body X-axis connecting portion  42  is one example of a first structure X-axis connecting portion, and the support body Y-axis connecting portion  52  is one example of a second structure Y-axis connecting portion. 
     The force receiving body X-axis connecting portion  42  connects the force receiving body  10  and the strain body  30 . The force receiving body  10  and the strain body  30  are connected by the two force receiving body X-axis connecting portions  42 . When seen along the Z-axis, the force receiving body X-axis connecting portions  42  are disposed on the positive side of the X-axis and the negative side of the X-axis relative to the strain body  30 . In the present embodiment, one of the force receiving body X-axis connecting portions  42  is disposed at a position on the positive side of the X-axis relative to the strain body  30 . This force receiving body X-axis connecting portion  42  connects the force receiving body  10  and the fourth strain body connecting portion  32   d . The other one of the force receiving body X-axis connecting portions  42  is disposed at a position on the negative side of the X-axis. This force receiving body X-axis connecting portion  42  connects the force receiving body  10  and the second strain body connecting portion  32   b.    
     The force receiving body X-axis connecting portion  42  according to the present embodiment is disposed on the X-axis, and extends along the X-axis. In the present embodiment, similar to the force receiving body Y-axis connecting portion  41 , the force receiving body X-axis connecting portion  42  is formed into a rectangular shape along the X-axis, the Y-axis, and the Z-axis. The dimension (equivalent to Lz in  FIG.  7   ) of the force receiving body X-axis connecting portion  42  in the Z-axis direction is greater than the dimension (P 2   x  in  FIG.  2   ) of the force receiving body X-axis connecting portion  42  in the X-axis direction. 
     As illustrated in  FIG.  2   , in the present embodiment, the dimension (P 2   y  in  FIG.  2   ) of the force receiving body X-axis connecting portion  42  in the Y-axis direction is smaller than the dimension (P 1   x  in  FIG.  2   ) of the force receiving body Y-axis connecting portion  41  in the X-axis direction. In other words, when seen along the Z-axis, the width of the force receiving body X-axis connecting portion  42  is smaller than the width of the force receiving body Y-axis connecting portion  41 . In addition, the dimension (P 2   x ) of the force receiving body X-axis connecting portion  42  in the X-axis direction may be equal to the dimension (Ply) of the force receiving body Y-axis connecting portion  41  in the Y-axis direction. 
     As illustrated in  FIGS.  2  to  4   , the support body Y-axis connecting portion  52  connects the strain body  30  and the support body  20 . The strain body  30  and the support body  20  are connected by the two support body Y-axis connecting portions  52 . When seen along the Z-axis, the support body Y-axis connecting portions  52  are disposed on the positive side of the Y-axis and the negative side of the Y-axis relative to the support body  20 . In the present embodiment, one of the support body Y-axis connecting portions  52  is disposed at a position on the positive side of the Y-axis relative to the support body  20 . This support body Y-axis connecting portion  52  connects the support body  20  and the first strain body connecting portion  32   a . The other one of the support body Y-axis connecting portions  52  is disposed at a position on the negative side of the Y-axis. This support body Y-axis connecting portion  52  connects the support body  20  and the third strain body connecting portion  32   c.    
     The support body Y-axis connecting portion  52  according to the present embodiment is disposed on the Y-axis, and extends along the Y-axis. In the present embodiment, similar to the force receiving body Y-axis connecting portion  41 , the support body Y-axis connecting portion  52  is formed into a rectangular shape along the X-axis, the Y-axis, and the Z-axis. The dimension (equivalent to Lz in  FIG.  7   ) of the support body Y-axis connecting portion  52  in the Z-axis direction is greater than the dimension (Q 2   y  in  FIG.  2   ) of the support body Y-axis connecting portion  52  in the Y-axis direction. 
     In the present embodiment, the dimension Q 2   x ) of the support body Y-axis connecting portion  52  in the X-axis direction is smaller than the dimension (Q 1   y ) of the support body X-axis connecting portion  51  in the Y-axis direction. In other words, when seen along the Z-axis, the width of the support body Y-axis connecting portion  52  is smaller than the width of the support body X-axis connecting portion  51 . In addition, the dimension (Q 2   y ) of the support body Y-axis connecting portion  52  in the Y-axis direction may be equal to the dimension (Q 1   x ) of the support body X-axis connecting portion  51  in the X-axis direction. 
     As illustrated in  FIG.  6   , the detection element  60  is configured to detect a displacement of the displacement portion  35  of each of the deformable bodies  31   a  to  31   d  described above in the Z-axis direction. The detection element  60  detects elastic deformation caused in the four deformable bodies  31   a  to  31   d  described above. The detection element  60  is configured as an element that detects capacitance. More specifically, as illustrated in  FIG.  2   , the detection element  60  includes a first capacitive element  61   a , a second capacitive element  61   b , a third capacitive element  61   c , and a fourth capacitive element  61   d . The first capacitive element  61   a  detects a displacement of the displacement portion  35  in the Z-axis direction caused by the elastic deformation of the first deformable body  31   a . The second capacitive element  61   b  detects a displacement of the displacement portion  35  in the Z-axis direction caused by the elastic deformation of the second deformable body  31   b . The third capacitive element  61   c  detects a displacement of the displacement portion  35  in the Z-axis direction caused by the elastic deformation of the third deformable body  31   c . The fourth capacitive element  61   d  detects a displacement of the displacement portion  35  in the Z-axis direction caused by the elastic deformation of the fourth deformable body  31   d.    
     As illustrated in  FIG.  6   , each of the capacitive elements  61   a  to  61   d  includes a displacement electrode  62  and a fixed electrode  63 . The displacement electrode  62  is provided on the lower surface  35   a  of the displacement portion  35 . When the displacement portion  35  is formed of an electrically conductive material, an insulating layer  64  may be interposed between the displacement portion  35  and the displacement electrode  62 . The fixed electrode  63  is provided on an upper surface  80   b  of the electrode support body  80  described later. When the electrode support body  80  is formed of an electrically conductive material, an insulating layer  65  may be interposed between the electrode support body  80  and the fixed electrode  63 . The displacement electrode  62  and the fixed electrode  63  are apart from each other, and face each other. This enables detection of capacitance between the displacement electrode  62  and the fixed electrode  63 . Even if the displacement electrode  62  is displaced in the X-axis direction, the Y-axis direction, and the Z-axis direction, the displacement electrode  62  may overlap the fixed electrode  63  as a whole, when seen along the Z-axis. Accordingly, the facing area of the displacement electrode  62  and the fixed electrode  63  can be restrained from changing, even if the displacement electrode  62  is displaced. Thus, a change in the facing area can be restrained from having influence on a change in a capacitance value. 
     As illustrated in  FIGS.  3  and  6   , the fixed electrode  63  of each of the capacitive elements  61   a  to  61   d  is supported by the electrode support body  80 . More specifically, the fixed electrode  63  is provided on the upper surface  80   b  of the electrode support body  80 . The electrode support body  80  may be mounted to the support body  20  by use of a non-illustrated bolt for example. Accordingly, the electrode support body  80  can be restrained from being displaced even if moment Mz acts on the force receiving body  10 . The electrode support body  80  may be formed into a circular ring shape when seen along the Z-axis. In addition, in  FIG.  3   , the upper surface  80   b  of the electrode support body  80  is in contact with the lower surface  10   b  of the force receiving body  10 , for convenience. However, a clearance may be formed between the force receiving body  10  and the electrode support body  80 . Alternatively, a packing  84  (see  FIG.  14   ) described later may be interposed between the force receiving body  10  and the electrode support body  80 . 
     As illustrated in  FIG.  3   , the detection circuit  70  is configured to output an electric signal indicating moment, based on a detection result of the detection element  60 . The detection circuit  70  may have, for example, a calculation function configured by a microprocessor. Moreover, the detection circuit  70  may have an A/D converting function of converting, into a digital signal, an analog signal received from the above-described detection element  60 , or a function of amplifying a signal. The detection circuit  70  may include a terminal that outputs an electric signal, and an electric signal is transmitted to the above-described control unit  1400  from this terminal via the electric cable  1300  (see  FIG.  1   ). 
     Next, a method of detecting moment acting on the torque sensor  1  in the present embodiment having such a configuration is described by use of  FIGS.  8  to  10   .  FIG.  8    is a plan view illustrating a case where moment about the Z-axis acts on the torque sensor  1  in the present embodiment.  FIG.  9    is a sectional view illustrating how the capacitance value of the capacitive element in  FIG.  6    decreases.  FIG.  10    is a sectional view illustrating how the capacitance value of the capacitive element in  FIG.  6    increases. 
     When the force receiving body  10  of the torque sensor  1  illustrated in  FIG.  2    receives the action of the moment Mz about the Z-axis, the first deformable portion  33  and the second deformable portion  34  of each of the deformable bodies  31   a  to  31   d  are elastically deformed, and a displacement in the Z-axis direction is caused to the displacement portion  35 . Thus, the distance between each of the displacement electrodes  62  of the detection element  60  and the corresponding fixed electrode  63  changes, and the capacitance value of each of the capacitive elements  61   a  to  61   d  changes. This change in capacitance value is detected by the detection element  60  as a displacement caused to the strain body  30 . A change in the capacitance value of each of the capacitive elements  61   a  to  61   d  can be varied. Thus, the detection circuit  70  can detect the magnitude of the moment Mz acting on the force receiving body  10 , based on a change in the capacitance value of each of the capacitive elements  61   a  to  61   d  detected by the detection element  60 . 
     A case where the moment Mz about the Z-axis acts on the force receiving body  10  of the torque sensor  1  in  FIG.  2    is described in more detail. Here, a case where the clockwise moment Mz acts toward the positive side in the Z-axis direction is described. 
     As illustrated in  FIG.  2   , the dimension (P 2   y ) of the force receiving body X-axis connecting portion  42  in the Y-axis direction is smaller than the dimension (P 1   x ) of the force receiving body Y-axis connecting portion  41  in the X-axis direction. Accordingly, when the moment Mz acts, the force receiving body X-axis connecting portion  42  becomes smaller in spring constant than the force receiving body Y-axis connecting portion  41 , and becomes easier to elastically deform. The force receiving body Y-axis connecting portion  41  becomes greater in spring constant, and substantially functions as a rigid body. Moreover, the dimension (Q 2   x ) of the support body Y-axis connecting portion  52  in the X-axis direction is smaller than the dimension (Q 1   y ) of the support body X-axis connecting portion  51  in the Y-axis direction. Accordingly, when the moment Mz about the Z-axis acts, the support body Y-axis connecting portion  52  becomes smaller in spring constant than the support body X-axis connecting portion  51 , and becomes easier to elastically deform. The support body X-axis connecting portion  51  becomes greater in spring constant, and substantially functions as a rigid body. 
     A change in the capacitance value of the first capacitive element  61   a  is described. The first strain body connecting portion  32   a  is connected to the force receiving body  10  via the force receiving body Y-axis connecting portion  41 , and connected to the support body  20  via the support body Y-axis connecting portion  52 . Accordingly, as illustrated in  FIG.  8   , the first strain body connecting portion  32   a  is supported by the force receiving body Y-axis connecting portion  41 , and displaced in the acting direction of the moment Mz. On the other hand, the fourth strain body connecting portion  32   d  is connected to the support body  20  via the support body X-axis connecting portion  51 , and connected to the force receiving body  10  via the force receiving body X-axis connecting portion  42 . Accordingly, the fourth strain body connecting portion  32   d  is supported by the support body X-axis connecting portion  51 , and is not substantially displaced. Thus, tensile force is applied to the first deformable body  31   a , and the displacement portion  35  of the first deformable body  31   a  is displaced to the Z-axis positive side, as illustrated in  FIG.  9   . In this case, the inter-electrode distance between the displacement electrode  62  and the fixed electrode  63  constituting the first capacitive element  61   a  is increased, and the capacitance value of the first capacitive element  61   a  is decreased. 
     A change in the capacitance value of the second capacitive element  61   b  is described. As illustrated in  FIG.  8   , the first strain body connecting portion  32   a  is supported by the force receiving body Y-axis connecting portion  41 , and is displaced in the acting direction of the moment Mz. On the other hand, the second strain body connecting portion  32   b  is connected to the support body  20  via the support body X-axis connecting portion  51 , and connected to the force receiving body  10  via the force receiving body X-axis connecting portion  42 . Accordingly, the second strain body connecting portion  32   b  is supported by the support body X-axis connecting portion  51 , and is not substantially displaced. Thus, compressive force is applied to the second deformable body  31   b , and the displacement portion  35  of the second deformable body  31   b  is displaced to the Z-axis negative side, as illustrated in  FIG.  10   . In this case, the inter-electrode distance between the displacement electrode  62  and the fixed electrode  63  constituting the second capacitive element  61   b  is decreased, and the capacitance value of the second capacitive element  61   b  is increased. 
     Similarly, tensile force is applied to the third deformable body  31   c  as illustrated in  FIG.  8   , and the displacement portion  35  of the third deformable body  31   c  is displaced to the Z-axis positive side, as illustrated in  FIG.  9   . In this case, the inter-electrode distance between the displacement electrode  62  and the fixed electrode  63  constituting the third capacitive element  61   c  is increased, and the capacitance value of the third capacitive element  61   c  is decreased. Moreover, compressive force is applied to the fourth deformable body  31   d  as illustrated in  FIG.  8   , and the displacement portion  35  of the fourth deformable body  31   d  is displaced to the Z-axis negative side as illustrated in  FIG.  10   . In this case, the inter-electrode distance between the displacement electrode  62  and the fixed electrode  63  constituting the fourth capacitive element  61   d  is decreased, and the capacitance value of the fourth capacitive element  61   d  is increased. 
     The moment Mz acting on the force receiving body  10  is detected by 
         Mz=−ΔC 1+Δ C 2−Δ C 3+Δ C 4.
 
     In addition, moment and a change amount of a capacitance value are connected by “=” for convenience in the equation below. However, because moment and a capacitance value are physical quantities different from each other, moment is actually calculated by converting a change amount of a capacitance value. ΔC 1  in the above equation indicates a change amount of the capacitance value of the first capacitive element  61   a , and ΔC 2  indicates a change amount of the capacitance value of the second capacitive element  61   b . αC 3  indicates a change amount of the capacitance value of the third capacitive element  61   c , and ΔC 4  indicates a change amount of the capacitance value of the fourth capacitive element  61   d.    
         C 1= C 01+Δ C 1, where
 
     C 01  is the capacitance value of the first capacitive element  61   a  in a neutral state, and C 1  is the capacitance value of the first capacitive element  61   a  when the moment Mz acts on the force receiving body  10 . Similarly, 
         C 2= C 02+Δ C 2
 
         C 3= C 03+Δ C 3
 
         C 4= C 04+Δ C 4.
 
     When C 01  to C 04  are the same, the moment Mz may be 
         Mz=−C 1+ C 2− C 3+ C 4,
 
     This is because C 01  to C 04  are offset. The neutral state means a state where no force or moment acts on the force receiving body  10 . 
     In this way, the torque sensor  1  according to the present embodiment can effectively detect the above-described moment Mz about the Z-axis. However, the torque sensor  1  according to the present embodiment is not suited to the detection of force or moment other than the moment Mz. This is described below. 
     (When Fx Acts) 
     When force Fx acts on the force receiving body  10  of the torque sensor  1  in  FIG.  2    on the positive side in the X-axis direction, tensile force is applied to the force receiving body X-axis connecting portion  42  located on the positive side of the X-axis, and the support body X-axis connecting portion  51  located on the positive side of the X-axis. Compressive force is applied to the force receiving body X-axis connecting portion  42  located on the negative side of the X-axis, and the support body X-axis connecting portion  51  located on the negative side of the X-axis. However, each of the force receiving body X-axis connecting portions  42  and each of the support body X-axis connecting portions  51  extend along the X-axis, therefore have a large spring constant in response to force in the X-axis direction, and substantially function as rigid bodies. Thus, the elastic deformation of the strain body  30  can be restrained, and the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing. When the force Fx acts on the force receiving body  10  on the X-axis negative side as well, the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing. When the strain body  30  is formed into a circular ring shape as in the present embodiment, the elastic deformation of the strain body  30  in response to the force Fx can be further restrained. 
     (When Fy Acts) 
     A case where force Fy acts on the force receiving body  10  of the torque sensor  1  in  FIG.  2    on the positive side of the Y-axis is described. Similar to the case where the Fx acts, each of the force receiving body Y-axis connecting portions  41  and each of the support body Y-axis connecting portions  52  extend along the Y-axis, therefore have a large spring constant in response to the force Fy in the Y-axis direction, and substantially function as rigid bodies. Thus, even if the force Fy acts, the elastic deformation of the strain body  30  can be restrained, and the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing. 
     (When Fz Acts) 
     A case where force Fz in the Z-axis direction acts on the force receiving body  10  of the torque sensor  1  in  FIG.  2    is described. As described above, the dimension of each of the force receiving body Y-axis connecting portions  41  in the Z-axis direction is greater than the dimension (P 1   y ) of the force receiving body Y-axis connecting portion  41  in the Y-axis direction, and the dimension of each of the force receiving body X-axis connecting portions  42  in the z-axis direction is greater than the dimension (P 2   x ) of the force receiving body X-axis connecting portion  42  in the X-axis direction. Moreover, the dimension of each of the support body X-axis connecting portions  51  in the Z-axis direction is greater than the dimension (Q 1   x ) of the support body X-axis connecting portion  51  in the X-axis direction, and the dimension of each of the support body Y-axis connecting portions  52  in the Z-axis direction is greater than the dimension (Q 2   y ) of the support body Y-axis connecting portion  52  in the Y-axis direction. Accordingly, each of the connecting portions  41 ,  42 ,  51 , and  52  has a large spring constant in response to force in the Z-axis direction, and substantially functions as a rigid body. The support body X-axis connecting portion  51  and the support body Y-axis connecting portion  52  are connected to the support body  20 , thereby restraining the strain body  30  from being displaced relative to the support body  20  in the z-axis direction. The force receiving body Y-axis connecting portion  41  and the force receiving body X-axis connecting portion  42  are connected to the strain body  30 , thereby restraining the force receiving body  10  from being displaced relative to the strain body  30  in the Z-axis direction. Thus, even if the force Fz acts on the force receiving body  10 , the elastic deformation of the strain body  30  can be restrained, and the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing. When the strain body  30  is formed into a circular ring shape as in the present embodiment, the elastic deformation of the strain body  30  in response to the force Fz can be further restrained. 
     (When Mx Acts) 
     A case where moment Mx about the X-axis acts on the force receiving body  10  of the torque sensor  1  in  FIG.  2    is described. In this case, torsional force about the X-axis acts on each of the force receiving body X-axis connecting portions  42  and each of the support body X-axis connecting portions  51 . Bending moment in the Z-axis direction acts on each of the force receiving body Y-axis connecting portions  41  and each of the support body Y-axis connecting portions  52 . However, each of the force receiving body Y-axis connecting portions  41  and each of the support body Y-axis connecting portions  52  have a large spring constant in response to force in the Z-axis direction, and substantially function as rigid bodies. Thus, even if the moment Mx acts on the force receiving body  10 , the elastic deformation of the strain body  30  can be restrained, and the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing. When the strain body  30  is formed into a circular ring shape as in the present embodiment, the elastic deformation of the strain body  30  in response to the moment Mx can be further restrained. 
     (When My Acts) 
     A case where moment My about the Y-axis acts on the force receiving body  10  of the torque sensor  1  in  FIG.  2    is described. Similar to the case where the moment Mx acts, each of the force receiving body X-axis connecting portions  42  and each of the support body X-axis connecting portions  51  have a large spring constant in response to force in the Z-axis direction, and substantially function as rigid bodies. Thus, even if the moment My acts on the force receiving body  10 , the elastic deformation of the strain body  30  can be restrained, and the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing. When the strain body  30  is formed into a circular ring shape as in the present embodiment, the elastic deformation of the strain body  30  in response to the moment My can be further restrained. 
     Hence, the torque sensor  1  according to the present embodiment is not suited to detection of force or moment other than the moment Mz about the Z-axis. Thus, the moment Mz about the Z-axis can be accurately detected. 
     In this way, according to the present embodiment, the force receiving body Y-axis connecting portions  41  that connect the force receiving body  10  and the strain body  30  are disposed on the positive side and negative side of the Y-axis relative to the strain body  30 , and the support body X-axis connecting portions  51  that connect the strain body  30  and the support body  20  are disposed on the positive side and negative side of the X-axis relative to the support body  20 . The strain body  30  includes the four deformable bodies  31   a  to  31   d  each including the displacement portion  35  that is displaced in the Z-axis direction by elastic deformation, and the detection element  60  includes the capacitive elements  61   a  to  61   d  that each detect a change in capacitance value by the displacement of the displacement portion  35  of each of the deformable bodies  31   a  to  31   d  in the Z-axis direction. Accordingly, when the moment Mz about the X-axis acts on the force receiving body  10 , tensile force or compressive force can be applied to each of the deformable bodies  31   a  to  31   d  of the strain body  30  disposed in the first to fourth quadrants. Thus, the displacement portion  35  of each of the deformable bodies  31   a  to  31   d  can be displaced in the Z-axis direction, and the displacement electrode  62  and the fixed electrode  63  constituting each of the capacitive elements  61   a  to  61   d  can be disposed so as to face in the Z-axis direction. In this case, the facing surfaces of the displacement electrode  62  and the fixed electrode  63  can be disposed along the XY plane, and the alignment of the displacement electrode  62  and the fixed electrode  63  can be facilitated. Moreover, the four fixed electrodes  63  disposed on the electrode support body  80  can be combined into a common fixed electrode, in which case as well, the alignment of the displacement electrode  62  and the fixed electrode  63  can be facilitated. As a result, the efficiency of manufacturing the torque sensor  1  can be improved. 
     Moreover, according to the present embodiment, the support body  20  is disposed inside the force receiving body  10 , when seen along the Z-axis. Accordingly, the force receiving body  10 , the strain body  30 , and the support body  20  can be disposed along the XY plane. Thus, the thickness (dimension in the Z-axis direction) of the torque sensor  1  can be lessened, and the torque sensor  1 , can be formed thinner. 
     Moreover, according to the present embodiment, the dimension of the force receiving body Y-axis connecting portion  41  in the Z-axis direction is greater than the dimension (P 1   y ) of the force receiving body Y-axis connecting portion  41  in the Y-axis direction, and the dimension of the support body X-axis connecting portion  51  in the Z-axis direction is greater than the dimension (Q 1   x ) of the support body X-axis connecting portion  51  in the X-axis direction. This allows the force receiving body Y-axis connecting portion  41  and the support body X-axis connecting portion  51  to substantially function as rigid bodies in response to force in the Z-axis direction. Thus, even if the force Fz in the Z-axis direction acts on the force receiving body  10 , the elastic deformation of each of the deformable bodies  31   a  to  31   d  of the strain body  30  can be restrained. Similarly, even if the moment Mx about the X-axis and the moment My about the Y-axis act on the force receiving body  10 , the elastic deformation of each of the deformable bodies  31   a  to  31   d  of the strain body  30  can be restrained. Thus, even if the force Fz the moment Mx, or the moment My acts, the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing, and the detection of the force Fz, the moment Mx, and the moment My can be restrained. 
     Moreover, according to the present embodiment, the force receiving body X-axis connecting portions  42  that connect the force receiving body  10  and the strain body  30  are disposed on the positive side and negative side of the X-axis relative to the strain body  30 . The support body X-axis connecting portions  51  that connect the strain body  30  and the support body  20  are disposed on the positive side and negative side of the X-axis relative to the support body  20 . The force receiving body X-axis connecting portion  42  and the support body X-axis connecting portion  51  each extend along the X-axis. Accordingly, even if the force Fx in the X-axis direction acts on the force receiving body  10 , the force receiving body X-axis connecting portion  42  and the support body X-axis connecting portion  51  can substantially function as rigid bodies, and the elastic deformation of each of the deformable bodies  31   a  to  31   d  of the strain body  30  can be restrained. Thus, even if the force Fx in the X-axis direction acts, the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing, and the detection of the force Fx can be restrained. 
     Moreover, according to the present embodiment, the force receiving body Y-axis connecting portions  41  that connect the force receiving body  10  and the strain body  30  are disposed on the positive side and negative side of the Y-axis relative to the strain body  30 . The support body Y-axis connecting portions  52  that connect the strain body  30  and the support body  20  are disposed on the positive side and negative side of the Y-axis relative to the support body  20 . The force receiving body Y-axis connecting portion  41  and the support body Y-axis connecting portion  52  each extend along the Y-axis. Accordingly, even if the force Fy in the Y-axis direction acts on the force receiving body  10 , the force receiving body Y-axis connecting portion  41  and the support body Y-axis connecting portion  52  can substantially function as rigid bodies, and the elastic deformation of each of the deformable bodies  31   a  to  31   d  of the strain body  30  can be restrained. Thus, even if the force Fy in the Y-axis direction acts, the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing, and the detection of the force Fy can be restrained. 
     Moreover, according to the present embodiment, the dimension of the force receiving body X-axis connecting portion  42  in the Z-axis direction is greater than the dimension (P 2   x ) of the force receiving body X-axis connecting portion  42  in the X-axis direction. Further, the dimension of the support body Y-axis connecting portion  52  in the Z-axis direction is greater than the dimension (Q 2   y ) of the support body Y-axis connecting portion  52  in the Y-axis direction. This allows the force receiving body X-axis connecting portion  42  and the support body Y-axis connecting portion  52  to substantially function as rigid bodies in response to force in the Z-axis direction. Thus, even if the force Fz in the Z-axis direction acts on the force receiving body  10 , the elastic deformation of each of the deformable bodies  31   a  to  31   d , of the strain body  30  can be further restrained. Similarly, even if the moment. Mx about the X-axis and the moment My about the Y-axis act on the force receiving body  10 , the elastic deformation of each of the deformable bodies  31   a  to  31   d  of the strain body  30  can be further restrained. Thus, even if the force Fz, the moment Mx, or the moment My acts, the capacitance value of each of the capacitive elements  61   a  to  61   d  can be further restrained from changing, and the detection of the force Fz, the moment Mx, and the moment My can be further restrained. 
     Moreover, according to the present embodiment, the dimension (P 2   y ) of the force receiving body X-axis connecting portion  42  in the Y-axis direction is smaller than the dimension (Pix) of the force receiving body Y-axis connecting portion  41  in the X-axis direction, and the dimension (Q 2   x ) of the support body Y-axis connecting portion  52  in the X-axis direction is smaller than the dimension (Q 1   y ) of the support body X-axis connecting portion  51 , in the Y-axis direction. This allows the force receiving body Y-axis connecting portion  41  and the support body X-axis connecting portion  51  to substantially function as rigid bodies when the moment Mz about the Z-axis acts, and the force receiving body X-axis connecting portion  42  and the support body Y-axis connecting portion  52  can be easily elastically deformed. Thus, tensile force or compressive force can be easily applied to each of the deformable bodies  31   a  to  31   d  of the strain body  30  disposed in the first to fourth quadrants. As a result, each of the displacement portions  35  of each of the deformable bodies  31   a  to  31   d  can be easily displaced in the Z-axis direction, and a change in the capacitance value of each of the capacitive elements  61   a  to  61   d  can be easily detected. 
     Moreover, according to the present embodiment, the strain body  30  is formed into a circular ring shape when seen along the Z-axis. Accordingly, the deformable bodies  31   a  to  31   d  can be connected to each other. Thus, even if force or moment other than the moment Mz about the Z-axis acts, the elastic deformation of each of the deformable bodies  31   a  to  31   d  of the strain body  30  can be restrained. As a result, even if force or moment other than the moment Mz acts, the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing, and the detection of force or moment other than the moment Mz can be restrained. 
     In addition, in the present embodiment described above, a case has been described where the force receiving body  10  and the strain body  30  are connected by the force receiving body X-axis connecting portion  42 , and the strain body  30  and the support body  20  are connected by the support body Y-axis connecting portion  52 . However, the present invention is not limited thereto. 
     For example, as illustrated in  FIG.  11   , the strain body  30  and the support body  20  does not need to be connected at the position of the strain body  30  where the force receiving body Y-axis connecting portion  41  is connected. That is to say, the first strain body connecting portion  32   a  and the third strain body connecting portion  32   c  does not need to be connected to the support body  20  by the support body Y-axis connecting portion  52  as illustrated in  FIG.  2   . Moreover, the force receiving body  10  and the strain body  30  do not need to be connected at the position of the strain body  30  where the support body X-axis connecting portion  51  is connected. That is to say, the second strain body connecting portion  32   b  and the fourth strain body connecting portion  32   d  do not need to be connected to the force receiving body  10  by the force receiving body X-axis connecting portion  42  as illustrated in  FIG.  2   .  FIG.  1   i    is a plan view illustrating a modification of h torque sensor in  FIG.  2   . 
     In the torque sensor  1  illustrated in  FIG.  11    as well, the force receiving body  10  and the strain body  30  are connected by the force receiving body Y-axis connecting portion  41 , and the strain body  30  and the support body  20  are connected by the support body X-axis connecting portion  51 . Accordingly, when the moment Mz about the Z-axis acts, tensile force or compressive force can be applied to each of the deformable bodies  31   a  to  31   d  of the strain body  30  disposed in the first to fourth quadrants. Thus, the displacement portion  35  of each of the deformable bodies  31   a  to  31   d  can be displaced in the Z-axis direction, and the displacement electrode  62  and the fixed electrode  63  constituting each of the capacitive elements  61   a  to  61   d  can be disposed so as to face in the Z-axis direction. In this case, the facing surfaces of the displacement electrode  62  and the fixed electrode  63  can be disposed along the XY plane, and the alignment of the displacement electrode  62  and the fixed electrode  63  can be facilitated. As a result, the efficiency of manufacturing the torque sensor  1  can be improved. 
     In this way, according to the modification illustrated in  FIG.  11   , the strain body  30  and the support body  20  are not connected at the position of the strain body  30  where the force receiving body Y-axis connecting portion  41  is connected, and the force receiving body  10  and the strain body  30  are not connected at the position of the strain body  30  where the support body X-axis connecting portion  51  is connected. Accordingly, while the efficiency of manufacturing the torque sensor  1  is improved, the structure of the torque sensor  1  can be simplified, and price lowering can be achieved. 
     Moreover, in the present embodiment described above, an example has been described in which one force receiving body Y-axis connecting portion  41  is disposed on each of the positive and negative sides of the Y-axis relative to the strain body  30 . However, the present invention is not limited thereto. 
     For example, as illustrated in  FIG.  12   , each of the force receiving body Y-axis connecting portions  41  may include two force receiving body Y-axis divided portions  41   a .  FIG.  12    is a plan view illustrating another modification of the torque sensor in  FIG.  2   . 
     In the modification illustrated in  FIG.  12   , the two force receiving body Y-axis divided portions  41   a  are respectively disposed on the positive and negative sides of the Y-axis relative to the strain body  30 . The force receiving body Y-axis divided portions  41   a  may be formed into a rectangular shape along the X-axis, the Y-axis, and the Z-axis. The dimension of the force receiving body Y-axis divided portion  41   a  in the X-axis direction may be greater than the dimension (P 2   y ) of the force receiving body X-axis connecting portion  42  in the Y-axis direction. The two force receiving body Y-axis divided portions  41   a  constituting one force receiving body Y-axis connecting portion  41  may be apart from each other in the X-axis direction, and may be parallel to each other. The two force receiving body Y-axis divided portions  41   a  constituting one force receiving body Y-axis connecting portion  41  may be disposed symmetrically with respect to the Y-axis. That is to say, one of the two force receiving body Y-axis divided portions  41   a  is disposed on the positive side of the X-axis relative to the Y-axis, and the other is disposed on the negative side of the X-axis relative to the Y-axis. In addition, the two force receiving body Y-axis divided portions  41   a  constituting one force receiving body Y-axis connecting portion  41  may be disposed asymmetrically with respect to the Y-axis. It may be that the two force receiving body Y-axis divided portions  41   a  are disposed on one of the positive and negative sides of the X-axis relative to the Y-axis, and are not disposed on the other. As illustrated in  FIG.  12   , the dimension (Pix in  FIG.  12   ) of the force receiving body Y-axis connecting portion  41  in the X-axis direction may be the dimension of the two force receiving body Y-axis divided portions  41   a  in the X-axis direction. 
     Similarly, as illustrated in  FIG.  12   , each of the support body X-axis connecting portions  51  may include two support body X-axis divided portions  51   a.    
     In the modification illustrated in  FIG.  12   , the two support body X-axis divided portions  51   a  are respectively disposed on the positive and negative sides of the Y-axis relative to the strain body  30 . The support body X-axis divided portions  51   a  may be formed into a rectangular shape along the X-axis, the Y-axis and the Z-axis. The dimension of the support body X-axis divided portion  51   a  in the Y-axis direction may be greater than the dimension (Q 2   x ) of the support body Y-axis connecting portion  52  in the X-axis direction. The two support body X-axis divided portions  51   a  constituting one support body X-axis connecting portion  51  may be apart from each other in the Y-axis direction, and may be parallel to each other. The two support body X-axis divided portions  51   a  constituting one support body X-axis connecting portion  51  may be disposed symmetrically with respect to the X-axis. That is to say, one of the two support body X-axis divided portions  51   a  is disposed on the positive side of the Y-axis relative to the X-axis, and the other is disposed on the negative side of the Y-axis relative to the X-axis. In addition, the two support body X-axis divided portions  51   a  constituting one support body X-axis connecting portion  51  may be disposed asymmetrically with respect to the X-axis. It may be that the two support body X-axis divided portions  51   a  are disposed on one of the positive and negative sides of the Y-axis relative to the X-axis, and are not disposed on the other. As illustrated in  FIG.  12   , the dimension (Q 1   y  in F  12 ) of the support body X-axis connecting portion  51  in the Y-axis direction may be the dimension of the two support body X-axis divided portions  51   a  in the Y-axis direction. 
     In this way, according to the modification illustrated in  FIG.  12   , the force receiving body Y-axis connecting portion  41  includes the two force receiving body Y-axis divided portions  41   a . Accordingly, while the moment Mz about the Z-axis acts on the force receiving body  10 , the rigidity of the force receiving body Y-axis connecting portion  41  can be increased. This can facilitate displacing each of the displacement portions  35  of each of the deformable bodies  31   a  to  31   d  of the strain body  30  in the Z-axis direction, and detect a change in the capacitance value of each of the capacitive elements  61   a  to  61   d.    
     Moreover, according to the modification illustrated in FIG.  12 , the support body X-axis connecting portion  51  includes the two support body X-axis divided portions  51   a . Accordingly, when the moment Mz about the Z-axis acts on the force receiving body  10 , the rigidity of the support body X-axis connecting portion  51  can be increased. This can facilitate displacing each of the displacement portions  35  of each of the deformable bodies  31   a  to  31   d  of the strain body  30  in the Z-axis direction, and detect a change in the capacitance value of each of the capacitive elements  61   a  to  61   d.    
     In addition, in the modification illustrated in  FIG.  12   , each of the force receiving body Y-axis connecting portions  41  may include three or more force receiving body Y-axis divided portions  41   a . Similarly, each of the support body X-axis connecting portions  51  may include three or more support body X-axis divided portions  51   a.    
     Moreover, in the modification illustrated in  FIG.  12   , the force receiving body  10  and the strain body  30  do not need to be connected by the force receiving body X-axis connecting portion  42  as in the modification illustrated in  FIG.  11   . The strain body  30  and the support body  20  do not need to be connected by the support body Y-axis connecting portion  52 . 
     Moreover, in the present embodiment described above, an example has been described in which the deformable bodies  31   a  to  31   d  each include the first deformable portion  33 , the second deformable portion  34 , and the displacement portion  35 , and the first deformable portion  33  and the second deformable portion  34  are tilted relative to the Z-axis, and extend linearly, when radially seen. However, the present invention is not limited thereto. 
     For example, as illustrated in  FIG.  13 A , the deformable bodies  31   a  to  31   d  may be continuously curved convexly toward the Z-axis negative side, when radially seen,  FIG.  13 A  is a sectional view illustrating a modification of the deformable body in  FIG.  6   . 
     In the modification illustrated in  FIG.  13 A  as well, when the moment Mz acts on the force receiving body  10 , tensile force or compressive force can be applied to each of the deformable bodies  31   a  to  31   d . Thus, the displacement portion  35  of each of the deformable bodies  31   a  to  31   d  can be displaced in the Z-axis direction, and the displacement electrode  62  and the fixed electrode  63  constituting each of the capacitive elements  61   a  to  61   d  can be disposed so as to face in the Z-axis direction. In the modification illustrated in  FIG.  13 A , the first deformable portion  33  and the second deformable portion  34  are curved, when radially seen. The displacement portion  35  may be formed into a linear shape similar to the displacement portion  35  illustrated in  FIG.  6   , when radially seen. However, as illustrated in  FIG.  13 A , the displacement portion  35  may be curved, when radially seen. In this case, the displacement portion  35  may be provided with a seat  36  for mounting the displacement electrode  62 . 
     According to the modification illustrated in  FIG.  13 A , the stress concentration of the first deformable portion  33  and the stress concentration of the second deformable portion  34  can be relaxed, and the reliability of the torque sensor  1  can be improved. 
     Furthermore, for example, as illustrated in  FIG.  13 B , a lower surface  33   a  of the first deformable portion  33  and the end face  32   e  of each of the strain body connecting portions  32   a  to  32   d  may be connected by a curved surface  37 . The curved surface  37  is curved convexly toward the Z-axis positive side, when radially seen. In this case, the stress concentration of the first deformable portion  33  can be further relaxed. A lower surface  34   a  of the second deformable portion  34  and the end face  32   e  of each of the strain body connecting portions  32   a  to  32   d  may also be connected by a curved surface  38  in a similar way.  FIG.  13 B  is a sectional view illustrating another modification of the deformable body in  FIG.  6   . 
     Moreover, the torque sensor  1  according to the present embodiment described above may further include a cover  81 . For example, as illustrated in  FIG.  14   , the cover  81  may be mounted to an inner peripheral surface  10   c  of the force receiving body  10 .  FIG.  14    is a sectional view illustrating a modification of the torque sensor in  FIG.  3   , and is a view equivalent to the section along the line A-A in  FIG.  2   . 
     The cover  81  may be mounted to the force receiving body  10  by a non-illustrated bolt for example. The cover  81  may have a cover opening  81   a . The cover  81  may be formed into a circular ring shape when seen along the Z-axis. In this case, blocking of the sensor opening  2  of the torque sensor  1  can be prevented, and a cable and a tube used in the robot can be passed through the sensor opening  2 . 
     As illustrated in  FIG.  14   , a packing  82  may be interposed between the cover  81  and the support body  20 . In this case, entrance of foreign objects such as dust into a space  83  between the force receiving body  10  and the support body  20  from the clearance between the cover  81  and the support body  20  can be prevented, and the reliability of the torque sensor  1  can be improved. The packing  82  may be a material that is soft enough not to inhibit a relative displacement between the force receiving body  10  and the support body  20  when the moment Mz acts. The packing  82  may be produced by, for example, silicone rubber. The packing  82  may be formed into a circular ring shape when seen along the Z-axis, similar to the support body  20 . 
     Moreover, as illustrated in  FIG.  14   , the packing  84  may be interposed between the force receiving body  10  and the electrode support body  80 . In this case, entrance of foreign objects such as dust into a space  83  between the force receiving body  10  and the support body  20  from the clearance between the force receiving body  10  and the electrode support body  80  can be restrained, and the reliability of the torque sensor  1  can be improved. The packing  84  may be a material that is soft enough not to inhibit a relative displacement between the force receiving body  10  and the support body  20  when the moment Mz acts. The packing  84  may be produced by, for example, silicone rubber. The packing  84  may be formed into a circular ring shape when seen along the Z-axis, similar to the force receiving body  10 . 
     Moreover, in the present embodiment described above, an example has been described in which the support body  20  is disposed inside the force receiving body  10  when seen along the Z-axis, so that the force receiving body  10  is equivalent to the first structure, and the support body  20  is equivalent to the second structure. However, the present invention is not limited thereto. For example, the force receiving body  10  may be disposed inside the support body  20  when seen along the Z-axis, so that the force receiving body  10  is equivalent to the second structure, and the support body  20  is equivalent to the first structure. In this case, as well, the strain body  30  may be disposed between the force receiving body  10  and the support body  20 . 
     Second Embodiment 
     Next, a torque sensor according to a second embodiment of the present invention is described by use of  FIGS.  15  and  16   . 
     The second embodiment illustrated in  FIGS.  15  and  16    is mainly different from the first embodiment illustrated in  FIGS.  1  to  14    in that the dimension (P 2   x ) of a force receiving body X-axis connecting portion  42  in the X-axis direction is greater than the dimension (P 1   y ) of a force receiving body Y-axis connecting portion  41  in the Y-axis direction, and the dimension (Q 2   y ) of a support body Y-axis connecting portion  52  in the Y-axis direction is greater than the dimension (Q 1   x ) of a support body X-axis connecting portion  51  in the X-axis direction. In other respects, the configuration according to the second embodiment is substantially the same as that according to the first embodiment. In addition, in  FIGS.  15  and  16   , the same reference signs are assigned to the same parts as those according to the first embodiment illustrated in  FIGS.  1  to  14   , and the detailed description of these parts is omitted. 
     A torque sensor  1  according to the present embodiment is described with reference to  FIG.  15   .  FIG.  15    is a plan view illustrating the torque sensor according to the second embodiment. 
     As illustrated in  FIG.  15   , in the torque sensor  1  according to the present embodiment, the dimension (P 2   x ) of the force receiving body X-axis connecting portion  42  in the X-axis direction is greater than the dimension (P 1   y ) of a force receiving body Y-axis connecting portion  41  in the Y-axis direction. In other words, when seen along the Z-axis, the length of the force receiving body X-axis connecting portion  42  is greater than the length of the force receiving body Y-axis connecting portion  41 . In  FIG.  15   , the dimension (P 2   y ) of the force receiving body X-axis connecting portion  42  in the Y-axis direction may be equal to the dimension (Pix) of the force receiving body Y-axis connecting portion  41  in the X-axis direction. However, the present invention is not limited thereto. As illustrated in  FIG.  2   , the dimension (P 2   y ) of the force receiving body X-axis connecting portion  42  in the Y-axis direction may be smaller than the dimension (P 1   x ) of the force receiving body Y-axis connecting portion  41  in the X-axis direction. 
     Similarly, the dimension (Q 2   y ) of the support body Y-axis connecting portion  52  in the Y-axis direction is greater than the dimension (Q 1   x ) of the support body X-axis connecting portion  51  in the X-axis direction. In other words, when seen along the Z-axis, the length of the support body Y-axis connecting portion  52  is greater than the length of the support body X-axis connecting portion  51 . In  FIG.  15   , the dimension (Q 2   x ) of the support body Y-axis connecting portion  52  in the X-axis direction may be equal to the dimension (Q 1   y ) of the support body X-axis connecting portion  51  in the Y-axis direction. However, the present invention is not limited thereto. As illustrated in  FIG.  2   , the dimension (Q 2   x ) of the support body Y-axis connecting portion  52  in the X-axis direction may be smaller than the dimension (Q 1   y  of the support body X-axis connecting portion  51  in the Y-axis direction. 
     As illustrated in  FIG.  15   , a strain body  30  may be formed into an elliptical ring shape so as to have a long axis along the Y-axis and a short axis along the X-axis, when seen along the Z-axis. In this case as well, a force receiving body  10 , the strain body  30 , and a support body  20  may be formed concentrically. The width of the strain body  30  may be circumferentially constant. In addition, in the present embodiment, each of deformable bodies  31   a  to  31   d  may be located at an intermediate point between the corresponding force receiving body Y-axis connecting portion  41  (or the support body Y-axis connecting portion  52 ) and the corresponding force receiving body X-axis connecting portion  42  (or the support body X-axis connecting portion  51 ) in a direction along the strain body  30 , when seen along the Z-axis. 
     The position of the strain body  30  where the force receiving body Y-axis connecting portion  41  is connected is disposed at a position closer to the force receiving body  10  than to the support body  20 . Moreover, the position of the strain body  30  where the support body X-axis connecting portion  51  is connected is disposed at a position closer to the support body  20  than to the force receiving body  10 . In this way, the position of the strain body  30  where the force receiving body Y-axis connecting portion  41  is connected is disposed at a position closer to the force receiving body  10  than the position where the force receiving body X-axis connecting portion  42  is connected. Accordingly, the dimension (P 2   x ) of the force receiving body X-axis connecting portion  42  in the X-axis direction can be greater than the dimension (P 1   y ) of the force receiving body Y-axis connecting portion  41  in the Y-axis direction. Moreover, the position of the strain body  30  where the support body X-axis connecting portion  51  is connected is disposed at a position closer to the support body  20  than the position where the support body Y-axis connecting portion  52  is connected. Accordingly, the dimension (Q 2   y ) of the support body Y-axis connecting portion  52  in the Y-axis direction can be greater than the dimension (Q 1   x ) of the support body X-axis connecting portion  51  in the X-axis direction. 
     As described above, the dimension (P 2   x ) of the force receiving body X-axis connecting portion  42  in the X-axis direction is greater than the dimension (P 1   y ) of the force receiving body Y-axis connecting portion  41  in the Y-axis direction. Accordingly, when moment Ma about the Z-axis acts, the force receiving body X-axis connecting portion  42  becomes smaller in spring constant than the force receiving body Y-axis connecting portion  41 , and becomes easier to elastically deform. The force receiving body Y-axis connecting portion  41  becomes greater in spring constant, and substantially functions as a rigid body. Moreover, the dimension (Q 2   y ) of the support body Y-axis connecting portion  52  in the Y-axis direction is greater than the dimension (Q 1   x ) of the support body X-axis connecting portion  51  in the X-axis direction. Accordingly, when moment Mz about the 2-axis acts, the support body Y-axis connecting portion  52  becomes smaller in spring constant than the support body X-axis connecting portion  51 , and becomes easier to elastically deform. The support body X-axis connecting portion  51  becomes greater in spring constant, and substantially functions as a rigid body. 
     When the moment Mz about the Z-axis acts, tensile force or compressive force as illustrated in  FIG.  8    can be applied to each of the deformable bodies  31   a  to  31   d  of the strain body  30  disposed in the first to fourth quadrants. Thus, a displacement portion  35  of each of the deformable bodies  31   a  to  31   d  can be displaced in the Z-axis direction, and a displacement electrode  62  and a fixed electrode  63  constituting each of capacitive elements  61   a  to  61   d  can be disposed so as to face in the Z-axis direction. In this case, the facing surfaces of the displacement electrode  62  and the fixed electrode  63  can be disposed along the XY plane, and the alignment of the displacement electrode  62  and the fixed electrode  63  can be facilitated. As a result, the efficiency of manufacturing the torque sensor  1  can be improved. 
     In this way, according to the present embodiment, the dimension (P 2   x ) of the force receiving body X-axis connecting portion  42  in the X-axis direction is greater than the dimension (P 1   y ) of the force receiving body Y-axis connecting portion  41  in the Y-axis direction, and the dimension (Q 2   y ) of the support body Y-axis connecting portion  52  in the Y-axis direction is greater than the dimension (Q 1   x ) of the support body X-axis connecting portion  51  in the X-axis direction. This allows the force receiving body Y-axis connecting portion  41  and the support body X-axis connecting portion  51  to substantially function as rigid bodies when moment Mz about the Z-axis acts, and the force receiving body X-axis connecting portion  42  and the support body Y-axis connecting portion  52  can be easily elastically deformed. Thus, tensile force or compressive force can be easily applied to each of the deformable bodies  31   a  to  31   d  of the strain body  30  disposed in the first to fourth quadrants. As a result, each of the displacement portions  35  of each of the deformable bodies  31   a  to  31   d  can be easily displaced in the Z-axis direction, and a change in the capacitance value of each of the capacitive elements  61   a  to  61   d  can be easily detected. 
     Moreover, according to the present embodiment, the strain body  30  may be formed into an elliptical ring shape so as to have a long axis along the Y-axis and a short axis along the X-axis, when seen along the Z-axis. Accordingly, the deformable bodies  31   a  to  31   d  can be connected to each other. Thus, even if force or moment other than the moment Mz about the Z-axis acts, the elastic deformation of each of the deformable bodies  31   a  to  31   d  of the strain body  30  can be restrained. As a result, even if force or moment other than the moment Mz acts, the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing, and the detection of force or moment other than the moment Mz can be restrained. Moreover, the strain body  30  is formed into an elliptical ring shape as described above, whereby the dimension (P 2   x ) of the force receiving body X-axis connecting portion  42  in the X-axis direction can be greater than the dimension (P 1   y ) of the force receiving body Y-axis connecting portion  41  in the Y-axis direction, and the dimension (Q 2   y ) of the support body Y-axis connecting portion  52  in the Y-axis direction can be greater than the dimension (Q 1   x ) of the support body X-axis connecting portion  51  in the X-axis direction. 
     In addition, in the present embodiment described above, an example has been described in which the strain body  30  is formed into an elliptical ring shape so as to have a long axis along the Y-axis and a short axis along the X-axis, when seen along the Z-axis. However, the present invention is not limited thereto. 
     For example, as illustrated in  FIG.  16   , the strain body  30  may be formed into a circular ring shape, and formed concentrically with the force receiving body  10  and the support body  20 , when seen along the Z-axis.  FIG.  16    is a plan view illustrating a modification of the torque sensor in  FIG.  15   . 
     In this case, a base portion  85  may be interposed between the force receiving body Y-axis connecting portion  41  and the strain body  30 . The base portion  85  may be formed so as to have a large spring constant in response to force or moment acting on the force receiving body  10 , and to substantially function as a rigid body. The force receiving body X-axis connecting portion  42  may be directly connected to the strain body  30 . Accordingly, the dimension (P 2   x ) of the force receiving body X-axis connecting portion  42  in the X-axis direction can be greater than the dimension (P 1   y ) of the force receiving body Y-axis connecting portion  41  in the Y-axis direction. The base portion  85  may be interposed not between the force receiving body Y-axis connecting portion  41  and the strain body  30  but between the force receiving body  10  and the force receiving body Y-axis connecting portion  41 . Alternatively, the base portion  85  may be interposed both between the force receiving body  10  and the force receiving body Y-axis connecting portion  41  and between the force receiving body Y-axis connecting portion  41  and the strain body  30 . 
     Similarly, a base portion  86  similar to the base portion  85  described above may be interposed between the strain body  30  and the support body X-axis connecting portion  51 . The base portion  86  may be interposed not between the strain body  30  and the support body X-axis connecting portion  51  but between the support body X-axis connecting portion  51  and the support body  20 . Alternatively, the base portion  86  may be interposed both between the strain body  30  and the support body X-axis connecting portion  51  and between the support body X-axis connecting portion  51  and the support body  20 . 
     Third Embodiment 
     Next, a torque sensor according to a third embodiment of the present invention is described by use of  FIGS.  17  and  18   . 
     The third embodiment illustrated in  FIGS.  17  and  18    is mainly different from the first embodiment illustrated in  FIGS.  1  to  14    in that a force receiving body Y-axis connecting portion  41  is formed at a connection position between a force receiving body  10  and a strain body  30 , and a support body X-axis connecting portion  51  is formed at a connection position between the strain body  30  and a support body  20 . In other respects, the configuration according to the third embodiment is substantially the same as that according to the first embodiment. In addition, in  FIGS.  17  and  18   , the same reference signs are assigned to the same parts as those according to the first embodiment illustrated in  FIGS.  1  to  14   , and the detailed description of these parts is omitted. 
     A torque sensor  1  according to the present embodiment is described with reference to  FIG.  17   .  FIG.  17    is a plan view illustrating the torque sensor according to the third embodiment. 
     As illustrated in  FIG.  17   , in the torque sensor  1  according to the present embodiment, the force receiving body Y-axis connecting portion  41  is formed at a connection position between the force receiving body  10  and the strain body  30 . An outer peripheral surface  30   c  of the strain body  30  may be formed into an elliptical shape so as to have a long axis along the Y-axis and a short axis along the X-axis, when seen along the Z-axis. An inner peripheral surface  30   d  of the strain body  30  may be formed into an elliptical shape so as to have a long axis along the Y-axis and a short axis along the X-axis, when seen along the Z-axis. Although the width of the strain body  30  is circumferentially constant in the example illustrated in  FIG.  17   , the present invention is not limited thereto. As long as the detection of force or moment other than moment Mz can be restrained, the width of the strain body  30  does not need to be constant. Moreover, although the width of the strain body  30  illustrated in  FIG.  17    is greater than the strain body  30  illustrated in  FIG.  15    and others for convenience, the width of the strain body  30  may be any width as long as the above-described force receiving body Y-axis connecting portion  41  according to the present embodiment and the support body X-axis connecting portion  51  described later can be formed. The force receiving body  10  and the strain body  30  are connected by a force receiving body X-axis connecting portion  42 . 
     A first strain body connecting portion  32   a  of the strain body  30  is connected to an inner peripheral surface  10   c  of the force receiving body  10 . The dimension (P 2   y ) of the force receiving body X-axis connecting portion  42  in the Y-axis direction is smaller than the dimension (P 1   x ) of the force receiving body Y-axis connecting portion  41  in the X-axis direction. Accordingly, the force receiving body Y-axis connecting portion  41  becomes greater in spring constant in response to the moment Mz about the Z-axis, and substantially functions as a rigid body. It is easier for the force receiving body X-axis connecting portion  42  to elastically deform in response to the moment M about the Z-axis. 
     The support body X-axis connecting portion  5  is formed at a connection position between the strain body  30  and the support body  20 . An outer peripheral surface  20   c  of the support body  20  may be formed into an elliptical shape so as to have a long axis along the X-axis and a short axis along the Y-axis, when seen along the Z-axis. An inner peripheral surface  20   d  of the support body  20  may be formed into a circular shape when seen along the Z-axis. This inner peripheral surface  20   d  defines a sensor opening  2 . In  FIG.  17   , the circular sensor opening  2  of the torque sensor  1  is formed inside the support body  20 . The strain body  30  and the support body  20  are connected by a support body Y-axis connecting portion  52 . 
     The support body  20  is connected to the inner peripheral surface  30   d  of the strain body  30  (a second strain body connecting portion  32   b  and a fourth strain body connecting portion  32   d ). The dimension (Q 2   x ) of the support body Y-axis connecting portion  52  in the X-axis direction is smaller than the dimension (Q 1   y ) of the support body X-axis connecting portion  51  in the Y-axis direction. Accordingly, the support body X-axis connecting portion  51  becomes greater in spring constant in response to the moment Mz about the Z-axis, and substantially functions as a rigid body. It is easier for the support body Y-axis connecting portion  52  to elastically deform in response to the moment Mz about the Z-axis. 
     When the moment Mz about the Z-axis acts, tensile force or compressive force as illustrated in  FIG.  8    can be applied to each of the deformable bodies  31   a  to  31   d  of the strain body  30  disposed in the first to fourth quadrants. Thus, a displacement portion  35  of each of the deformable bodies  31   a  to  31   d  can be displaced in the Z-axis direction, and a displacement electrode  62  and a fixed electrode  63  constituting each of capacitive elements  61   a  to  61   d  can be disposed so as to face in the Z-axis direction. In this case, the facing surfaces of the displacement electrode  62  and the fixed electrode  63  can be disposed along the XY plane, and the alignment of the displacement electrode  62  and the fixed electrode  63  can be facilitated. As a result, the efficiency of manufacturing the torque sensor  1  can be improved. 
     In this way, according to the present embodiment, the force receiving body Y-axis connecting portion  41  is formed at a connection position between the force receiving body  10  and the strain body  30 , and the support body X-axis connecting portion  51  is formed at a connection position between the strain body  30  and the support body  20 . This allows the force receiving body Y-axis connecting portion  41  and the support body X-axis connecting portion  51  to substantially function as rigid bodies when moment Mx about the Z-axis acts, and the force receiving body X-axis connecting portion  42  and the support body Y-axis connecting portion  52  can be easily elastically deformed. Thus, tensile force or compressive force can be easily applied to each of the deformable bodies  31   a  to  31   d  of the strain body  30  disposed in the first to fourth quadrants. As a result, each of the displacement portions  35  of each of the deformable bodies  31   a  to  31   d  can be easily displaced in the Z-axis direction, and a change in the capacitance value of each of the capacitive elements  61   a  to  61   d  can be easily detected. 
     Moreover, according to the present embodiment, the outer peripheral surface  30   c  of the strain body  30  is formed into an elliptical shape so as to have a long axis along the Y-axis and a short axis along the X-axis, when seen along the Z-axis. Accordingly, the strain body  30  can be connected to the inner peripheral surface  10   c  of the force receiving body  10 , and the force receiving body Y-axis connecting portion  41  can be formed at a connection position between the force receiving body  10  and the strain body  30 . This allows the force receiving body Y-axis connecting portion  41  to substantially function as a rigid body in response to the moment Mz about the Z-axis. 
     Moreover, according to the present embodiment, the outer peripheral surface  20   c  of the support body  20  may be formed into an elliptical shape so as to have a long axis along the X-axis and a short axis along the Y-axis, when seen along the Z-axis. Accordingly, the support body  20  can be connected to the inner peripheral surface  30   d  of the strain body  30 , and the support body X-axis connecting portion  51  can be formed at a connection position between the strain body  30  and the support body  20 . This allows the support body X-axis connecting portion  51  to substantially function as a rigid body in response to the moment Mz about the Z-axis. 
     Moreover, according to the present embodiment, the dimension (P 2   y ) of the force receiving body X-axis connecting portion  42  in the Y-axis direction is smaller than the dimension (P 1   x ) of the force receiving body Y-axis connecting portion  41  in the X-axis direction, and the dimension (Q 2   x ) of the support body Y-axis connecting portion  52  in the X-axis direction is smaller than the dimension (Q 1   y ) of the support body X-axis connecting portion  51  in the Y-axis direction. This allows the force receiving body Y-axis connecting portion  41  and the support body X-axis connecting portion  51  to substantially function as rigid bodies when moment Ma about the Z-axis acts, and the force receiving body X-axis connecting portion  42  and the support body Y-axis connecting portion  52  can be easily elastically deformed, Thus, tensile force or compressive force can be easily applied to each of the deformable bodies  31   a  to  31   d  of the strain body  30  disposed in the first to fourth quadrants. As a result, each of the displacement portions  35  of each of the deformable bodies  31   a  to  31   d  can be easily displaced in the Z-axis direction, and a change in the capacitance value of each of the capacitive elements  61   a  to  61   d  can be easily detected. 
     In addition, in the above-described present embodiment, an example has been described in which the outer peripheral surface  20   c  of the support body  20  is formed into an elliptical shape so as to have a long axis along the X-axis and a short axis along the Y-axis, when seen along the Z-axis. However, the present invention is not limited thereto. For example, as illustrated in  FIG.  2    and others, the outer peripheral surface  20   c  of the support body  20  may be formed into a circular shape. Moreover, the inner peripheral surface  20   d  of the support body  20  may be formed into an elliptical shape so as to have a long axis along the X-axis and a short axis along the Y-axis, when seen along the Z-axis. 
     Moreover, in the present embodiment described above, an example has been described n which the force receiving body  10  and the strain body  30  are connected by the force receiving body X-axis connecting portion  42 , and the strain body  30  and the support body  20  are connected by the support body Y-axis connecting portion  52 . However, the present invention is not limited thereto. 
     For example, as illustrated in  FIG.  18   , the strain body  30  and the support body  20  do not need to be connected at the position of the strain body  30  where the force receiving body Y-axis connecting portion  41  is connected. That is to say, the first strain body connecting portion  32   a  and a third strain body connecting portion  32   c  do not need to be connected to the support body  20  by the support body Y-axis connecting portion  52  as illustrated in  FIG.  17   . Moreover, the force receiving body  10  and the strain body  30  do not need to be connected at the position of the strain body  30  where the support body X-axis connecting portion  51  is connected. That is to say, the second strain body connecting portion  32   b  and the fourth strain body connecting portion  32   d  do not need to be connected to the force receiving body  10  by the force receiving body X-axis connecting portion  42  as illustrated in  FIG.  17   .  FIG.  18    is a plan view illustrating a modification of the torque sensor in  FIG.  17   . 
     In the torque sensor illustrated in  FIG.  18    as well, the force receiving body  10  and the strain body  30  are connected by the force receiving body Y-axis connecting portion  41 , and the strain body  30  and the support body  20  are connected by the support body X-axis connecting portion  51 . Accordingly, when the moment Mz about the Z-axis acts, tensile force or compressive force can be applied to each of the deformable bodies  31   a  to  31   d  of the strain body  30  disposed in the first to fourth quadrants. Thus, the displacement portion  35  of each of the deformable bodies  31   a  to  31   d  can be displaced in the Z-axis direction, and the displacement electrode  62  and the fixed electrode  63  constituting each of the capacitive elements  61   a  to  61   d  can be disposed so as to face in the Z-axis direction. In this case, the facing surfaces of the displacement electrode  62  and the fixed electrode  63  can be disposed along the XY plane, and the alignment of the displacement electrode  62  and the fixed electrode  63  can be facilitated. As a result, the efficiency of manufacturing the torque sensor  1  can be improved. 
     In this way, according to the modification illustrated in  FIG.  18   , the strain body  30  and the support body  20  are not connected at the position of the strain body  30  where the force receiving body Y-axis connecting portion  41  is connected, and the force receiving body  10  and the strain body  30  are not connected at the position of the strain body  30  where the support body X-axis connecting portion  51  is connected. 
     Accordingly, while the efficiency of manufacturing the torque sensor  1  is improved, the structure of the torque sensor  1  can be simplified, and price lowering can be achieved. 
     Fourth Embodiment 
     Next, a torque sensor according to a fourth embodiment of the present invention is described by use of  FIGS.  19  to  22   . 
     The fourth embodiment illustrated in  FIGS.  19  to  22    is mainly different from the first embodiment illustrated in  FIGS.  1  to  14    in that a strain body  30  is disposed on the negative side of the Z-axis relative to a force receiving body  10 , and a support body  20  is disposed on the negative side of the Z-axis relative to the strain body  30 . In other respects, the configuration according to the fourth embodiment is substantially the same as that according to the first embodiment. In addition in  FIGS.  19  to  22   , the same reference signs are assigned to the same parts as those according to the first embodiment illustrated in  FIGS.  1  to  14   , and the detailed description of these parts is omitted. 
     A torque sensor  1  according to the present embodiment is described with reference to  FIGS.  19  to  21   .  FIG.  19    is a sectional view illustrating the torque sensor according to the fourth embodiment.  FIG.  20    is a sectional view along the line B-B in  FIG.  19   .  FIG.  21    is a sectional view along the line C-C in  FIG.  19   . 
     As illustrated in  FIG.  19   , in the torque sensor  1  according to the present embodiment, the strain body  30  is disposed on the negative side of the Z-axis relative to the force receiving body  10 , and the support body  20  is disposed on the negative side of the Z-axis relative to the strain body  30 . That is to say, the force receiving body  10 , the strain body  30 , and a support body  20  are stacked in the Z-axis direction. The force receiving body  10 , the strain body  30 , and a support body  20  may be each formed into a circular ring shape, or formed concentrically with one another, when seen along the Z-axis. As illustrated in  FIGS.  20  and  21   , a sensor opening  2  of the torque sensor  1  is formed inside the force receiving body  10 , inside the strain body  30 , and inside the support body  20 . 
     As illustrated in  FIG.  19   , a force receiving body Y-axis connecting portion  41  according to the present embodiment is disposed between the force receiving body  10  and the strain body  30  in the Z-axis direction. As illustrated in  FIG.  20   , the force receiving body Y-axis connecting portion  41  overlaps the force receiving body  10  and the strain body  30 , when seen along the Z-axis. The force receiving body Y-axis connecting portion  41  extends along the Y-axis, and extends along the Z-axis. In the present embodiment, the force receiving body Y-axis connecting portion  41  is formed into a rectangular shape along the X-axis, the Y-axis, and the Z-axis. The dimension of the force receiving body Y-axis connecting portion  41  in the Z-axis direction may be greater than the dimension (P 1   y ) of the force receiving body Y-axis connecting portion  41  in the Y-axis direction, but does not need to be greater. 
     As illustrated in  FIG.  19   , a force receiving body X-axis connecting portion  42  according to the present embodiment is disposed between the force receiving body  10  and the strain body  30  in the Z-axis direction. As illustrated in  FIG.  20   , the force receiving body X-axis connecting portion  42  overlaps the force receiving body  10  and the strain body  30 , when seen along the Z-axis. The force receiving body X-axis connecting portion  42  extends along the X-axis, and extends along the Z-axis. In the present embodiment, the force receiving body X-axis connecting portion  42  is formed into a rectangular shape along the X-axis, the Y-axis, and the Z-axis. The dimension of the force receiving body X-axis connecting portion  42  in the Z-axis direction may be greater than the dimension (P 2   x ) of the force receiving body X-axis connecting portion  42  in the X-axis direction, but does not need to be greater. 
     In the present embodiment, a displacement portion  35  of each of deformable bodies  31   a  to  31   d  of a strain body  30  may face an upper surface  20   a  of the support body  20 . In this case, a fixed electrode  63  constituting each of capacitive elements  61   a  to  61   d  may be provided on the upper surface  20   a  of the support body  20 . However, the present invention is not limited thereto, and the displacement portion  35  may face a lower surface  10   b  of the force receiving body  10 . In this case, the fixed electrode  63  may be provided on the lower surface  10   b  of the force receiving body  10 . 
     As illustrated in  FIG.  20   , in the present embodiment, the dimension (P 2   y ) of the force receiving body X-axis connecting portion  42  in the Y-axis direction is smaller than the dimension (P 1   x ) of the force receiving body Y-axis connecting portion  41  in the X-axis direction. 
     As illustrated in  FIG.  19   , a support body X-axis connecting portion  51  according to the present embodiment is disposed between the strain body  30  and the support body  20  in the Z-axis direction. As illustrated in  FIG.  21    the support body X-axis connecting portion  51  overlaps the strain body  30  and the support body  20 , when seen along the Z-axis. The support body X-axis connecting portion  51  extends along the X-axis, and extends along the Z-axis. In the present embodiment, the support body X-axis connecting portion  51  is formed into a rectangular shape along the X-axis, the Y-axis, and the Z-axis. The dimension of the support body X-axis connecting portion  51  in the Z-axis direction may be greater than the dimension (Q 1   x ) of the support body X-axis connecting portion  51  in the X-axis direction, but does not need to be greater. 
     As illustrated in  FIG.  19   , a support body Y-axis connecting portion  52  according to the present embodiment is disposed between the strain body  30  and the support body  20  in the Z-axis direction. As illustrated in  FIG.  21   , the support body Y-axis connecting portion  52  overlaps the strain body  30  and the support body  20 , When seen along the Z-axis. The support body Y-axis connecting portion  52  extends along the Y-axis, and extends along the Z-axis. In the present embodiment, the support body Y-axis connecting portion  52  is formed into a rectangular shape along the X-axis, the Y-axis, and the Z-axis. The dimension of the support body Y-axis connecting portion  52  in the Z-axis direction may be greater than the dimension (Q 2   y ) of the support body Y-axis connecting portion  52  in the Y-axis direction, but does not need to be greater. 
     As illustrated in  FIG.  21   , in the present embodiment, the dimension (Q 2   x ) of the support body Y-axis connecting portion  52  in the X-axis direction is smaller than the dimension (Q 1   y ) of the support body X-axis connecting portion  51  in the Y-axis direction. 
     When the moment Mz about the Z-axis acts, the force receiving body Y-axis connecting portion  41  substantially functions as a rigid body, and the force receiving body X-axis connecting portion  42  is elastically deformed. Moreover, the support body X-axis connecting portion  51  substantially functions as a rigid body, and the support body Y-axis connecting portion  52  is elastically deformed. Accordingly, tensile force or compressive force as illustrated in  FIG.  8    can be applied to each of the deformable bodies  31   a  to  31   d  of the strain body  30  disposed in the first to fourth quadrants. Thus, the displacement portion  35  of each of the deformable bodies  31   a  to  31   d  can be displaced in the Z-axis direction, and the displacement electrode  62  and the fixed electrode  63  constituting each of the capacitive elements  61   a  to  61   d  can be disposed so as to face in the Z-axis direction. In this case, the facing surfaces of the displacement electrode  62  and the fixed electrode  63  can be disposed along the XY plane, and the alignment of the displacement electrode  62  and the fixed electrode  63  can be facilitated. As a result, the efficiency of manufacturing the torque sensor  1  can be improved. 
     In this way, according to the present embodiment, the support body  20  is disposed on the negative side of the Z-axis relative to the strain body  30 . Accordingly, the sensor opening  2  of the torque sensor  1 , can be enlarged. When the torque sensor  1  is applied to a robot, a cable and a tube used in the robot are often passed through the sensor opening  2  of the torque sensor  1 . Thus, when the strain body  30  and the support body  20  are stacked in the Z-axis direction as in the present embodiment, the sensor opening  2  of the torque sensor  1  can be enlarged, and a cable and a tube can be easily passed through. Usability of the torque sensor  1  can be improved. 
     Moreover, according to the present embodiment, the strain body  30  is disposed on the negative side of the Z-axis relative to the force receiving body  10 , Accordingly, the sensor opening  2  of the torque sensor  1  can be further enlarged. Thus, a cable and a tube used in the robot can be more easily passed through, and usability of the torque sensor  1  can be further improved. 
     Moreover, according to the present embodiment, the force receiving body X-axis connecting portion  42  and the support body X-axis connecting portion  51  each extend along the X-axis. Accordingly, even if the force Fy in the X-axis direction acts on the force receiving body  10 , the force receiving body X-axis connecting portion  42  and the support body X-axis connecting portion  51  can substantially function as rigid bodies, and the elastic deformation of each of the deformable bodies  31   a  to  31   d  of the strain body  30  can be restrained. Thus, even if the force Fx in the X-axis direction acts, the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing, and the detection of the force Fx can be restrained. 
     Moreover, according to the present embodiment, the force receiving body Y-axis connecting portion  41  and the support body Y-axis connecting portion  52  each extend along the Y-axis. Accordingly, even if the force Fy in the Y-axis direction acts on the force receiving body  10 , the force receiving body Y-axis connecting portion  41  and the support body Y-axis connecting portion  52  can substantially function as rigid bodies, and the elastic deformation of each of the deformable bodies  31   a  to  31   d  of the strain body  30  can be restrained. Thus, even if the force Fy in the Y-axis direction acts, the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing, and the detection of the force Fy can be restrained. 
     Moreover, according to the present embodiment, the force receiving body Y-axis connecting portion  41 , the force receiving body X-axis connecting portion  42 , the support body X-axis connecting portion  51 , and the support body Y-axis connecting portion  52  each extend along the Z-axis. This allows each of the connecting portions  41 ,  42 ,  51 , and  52  to substantially function as a rigid body in response to force in the Z-axis direction. Thus, even if the force Fz in the Z-axis direction acts on the force receiving body  10 , the elastic deformation of the deformable bodies  31   a  to  31   d  of the strain body  30  can be restrained. Similarly, even if the moment Mx about the X-axis and the moment My about the Y-axis act on the force receiving body  10 , the elastic deformation of each of the deformable bodies  31   a  to  31   d  of the strain body  30  can be restrained. Thus, even if the force Fz, the moment Mx, or the moment My acts, the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing, and the detection of the force Fz, the moment Mx, or the moment My can be restrained. 
     Moreover, according to the present embodiment, the dimension (P 2   y ) of the force receiving body X-axis connecting portion  42  in the Y-axis direction is smaller than the dimension (P 1   x ) of the force receiving body Y-axis connecting portion  41  in the X-axis direction, and the dimension (Q 2   x ) of the support body Y-axis connecting portion  52  in the X-axis direction is smaller than the dimension (Q 1   y ) of the support body X-axis connecting portion  51  in the Y-axis direction. This allows the force receiving body Y-axis connecting portion  41  and the support body X-axis connecting portion  51  to substantially function as rigid bodies when moment Mz about the Z-axis acts, and the force receiving body X-axis connecting portion  42  and the support body Y-axis connecting portion  52  can be easily elastically deformed. Thus, tensile force or compressive force can be easily applied to each of the deformable bodies  31   a  to  31   d  of the strain body  30  disposed in the first to fourth quadrants. As a result, each of the displacement portions  35  of each of the deformable bodies  31   a  to  31   d  can be easily displaced in the Z-axis direction, and a change in the capacitance value of each of the capacitive elements  61   a  to  61   d  can be easily detected. 
     Moreover, according to the present embodiment, the strain body  30  is formed into a circular ring shape when seen along the Z-axis. Accordingly, the deformable bodies  31   a  to  31   d  can be connected to each other. Thus, even if force or moment other than the moment Mz about the Z-axis acts, the elastic deformation of each of the deformable bodies  31   a  to  31   d  of the strain body  30  can be restrained. As a result, even if force or moment other than the moment Mz acts, the capacitance value of each of the capacitive elements  61   a  to  61   d  can be restrained from changing, and the detection of force or moment other than the moment Mz can be restrained. 
     In addition, in the present embodiment described above, an example has been described in which the strain body  30  is disposed on the negative side of the Z-axis relative to the force receiving body  10 , and the support body  20  is disposed on the negative side of the Z-axis relative to the strain body  30 . However, the present invention is not limited thereto. For example, as illustrated in  FIG.  22    the force receiving body  10  and the strain body  30  may be disposed along the ICY plane, and the support body  20  may be disposed on the negative side of the Z-axis relative to the strain body  30 . In this case as well, similar advantageous effects to the torque sensor  1  illustrated in  FIG.  19    can be exerted, and the height dimension of the torque sensor  1  can be reduced. Moreover, in this case, the fixed electrode  63  of the detection element  60  may be mounted on the upper surface  20   a  of the support body  20 .  FIG.  22    is a sectional view illustrating a modification of the torque sensor in  FIG.  19   , and is a view equivalent to the section along the line A-A in  FIG.  2   . 
     The present invention is not limited to the embodiments and modifications described above, and can be embodied by modifying the components without departing from the spirit thereof at the stage of implementation. Moreover, various inventions can be formed by a suitable combination of a plurality of components disclosed in the embodiments and modifications described above. Some components may be deleted from all of the components disclosed in the embodiments and modifications described above. Further, the components in different embodiments and modifications may be suitably combined.