Strain-generating body, force sensor device

Abstract

To provide a distortion-generating body capable of achieving both high load resistance and displacement.SOLUTION: A distortion-generating body of the present invention includes: a distortion-generating part including a movable part that deforms by receiving a predetermined force or moment in an axial direction and a non-movable part that does not deform under the force or moment; and an input transmission part that is joined to the non-movable part and does not deform under the force or moment. The input transmission part includes an accommodation part that can accommodate a sensor chip that detects the force or moment, and transmits the deformation of the distortion-generating body to the sensor chip.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a strain generating body and a force sensor device. [Background technology]

[0002] Conventionally, force sensor devices that detect displacement in a predetermined axial direction have been known. One example is a force sensor device that includes a structure consisting of a sensor chip, an external force application plate that is arranged around the sensor chip and to which an external force is applied, a base that supports the sensor chip, an external force buffering mechanism that fixes the external force application plate to the base, and a connecting rod that is an external force transmission mechanism, and in which the external force application plate and an action part are connected by the connecting rod (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-254843 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the case of the strain-generating bodies used in conventional force sensor devices, the structure that receives the force and the structure that transmits the displacement are integrated or closely connected to each other, so there is a strong trade-off between the displacement and the load capacity, making it particularly difficult to increase the load capacity.

[0005] The present invention has been made in consideration of the above-mentioned points, and has an object to provide a strain body that can achieve both high load resistance and large displacement. [Means for solving the problem]

[0006] The present strain-generating body (200) has a strain-generating part (220) including a movable part that deforms when subjected to a force or moment in a predetermined axial direction, and a non-movable part that does not deform when subjected to the force or moment, and an input transmission part (230) that is joined to the non-movable part and does not deform when subjected to the force or moment, the input transmission part (230) includes a housing part (235) capable of housing a sensor chip (100) that detects the force or moment, and the sensor chip (100) that can be housed in the housing part (235) is a first sensor chip (100) whose relative positions to each other change when subjected to the force or moment. a first connection portion (224) extending toward the input transmission portion (230) and connected to one of the first portion and the second portion, the accommodation portion (235) having a second connection portion (235c) connected to the other of the first portion and the second portion, the first connection portion (224) transmitting deformation of the strain-flexing portion (220) to the sensor chip (100) in response to the force or moment, a positional relationship between the first portion and the second portion changing in response to the deformation, and the second connection portion (235c) not deforming in response to the force or moment. death , The input transmission portion (230) has a second frame portion, a second central portion disposed inside the second frame portion and spaced apart from the second frame portion, and a plurality of second beam structures bridging the second frame portion and the second central portion, and the second central portion includes a third frame portion connected to the second beam structure, and the accommodation portion (235) extending from the third frame portion toward the strain-flexing portion (220). .

[0007] The reference symbols in parentheses are given for ease of understanding, are merely examples, and are not intended to be limiting of the embodiments shown in the drawings. Effect of the Invention

[0008] According to the disclosed technology, it is possible to provide a strain element that can achieve both high load resistance and displacement. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view illustrating a force sensor device according to a first embodiment; [Diagram 2] 1 is a cross-sectional perspective view illustrating a force sensor device according to a first embodiment; [Diagram 3] 1 is a top perspective view showing a state in which a sensor chip is attached to an input transmission section; FIG. [Figure 4] 1 is a bottom perspective view showing a state in which the sensor chip is attached to an input transmission section; FIG. [Diagram 5] 1 is a perspective view of the sensor chip 100 as viewed from above in the Z-axis direction. [Figure 6] 1 is a plan view of the sensor chip 100 as viewed from above in the Z-axis direction. [Figure 7] 2 is a perspective view of the sensor chip 100 as viewed from below in the Z-axis direction. FIG. [Figure 8] 1 is a bottom view of the sensor chip 100 as viewed from below in the Z-axis direction. [Figure 9] FIG. 2 is a diagram illustrating symbols indicating forces and moments acting on each axis. [Figure 10] 2 is a diagram illustrating an example of the arrangement of piezoresistance elements of the sensor chip 100. FIG. [Figure 11] 11 is a partial enlarged view of a pair of detection blocks of the sensor chip shown in FIG. 10. [Figure 12] FIG. 1 is a diagram (part 1) showing an example of a detection circuit using piezoresistance elements. [Figure 13] FIG. 2 is a diagram (part 2) showing an example of a detection circuit using piezoresistance elements. [Figure 14] FIG. 13 is a diagram illustrating an Fx input. [Figure 15] FIG. 13 is a diagram illustrating an Fy input. [Figure 16] This is the simulation result when there is an Fx input to the sensor chip. [Figure 17] This is a simulation result when Mz input is applied to the sensor chip. [Figure 18] This is a simulation result when Fz input is applied to the sensor chip. [Figure 19] FIG. 19 is a partial perspective view corresponding to FIG. 18. [Figure 20] FIG. 4 is a perspective view illustrating a force-receiving plate that constitutes the strain body. [Figure 21] FIG. 2 is a perspective view illustrating a strain-generating portion that configures a strain-generating body. [Figure 22] FIG. 2 is a perspective view of the upper surface side illustrating an input transmission portion that configures the strain body. [Diagram 23] FIG. 4 is a perspective view of the lower surface side illustrating an input transmission portion that configures the strain body. [Figure 24] FIG. 4 is a side view illustrating an input transmission portion that configures the strain body. [Diagram 25] FIG. 4 is a perspective view illustrating a cover plate that constitutes a strain generating body. [Figure 26] This is the simulation result when Fx input is applied to the strain-generating part. [Figure 27] This is the simulation result when Mz input is applied to the strain-generating part. [Figure 28] 1 is a plan view of the sensor chip 100A as viewed from above in the Z-axis direction. [Figure 29] 1 is a partial plan view of the sensor chip 100B as viewed from above in the Z-axis direction. [Diagram 30] 1 is a partial plan view of the sensor chip 100C as viewed from above in the Z-axis direction. [Diagram 31] FIG. 2 is a perspective view of a flexure body 200A. [Diagram 32] FIG. 2 is a cross-sectional perspective view of a flexure body 200A. [Diagram 33] FIG. 4 is a perspective view illustrating an input transmission portion that configures the strain body. [Diagram 34] FIG. 4 is a perspective view illustrating a cover plate that constitutes a strain generating body. [Diagram 35] FIG. 4 is a side view of a strain body 200B. [Diagram 36] FIG. 4 is a perspective view of the lower surface side illustrating a strain-generating portion that configures the strain-generating body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and duplicated explanations may be omitted.

[0011] First embodiment (Schematic configuration of the force sensor device 1) Fig. 1 is a perspective view illustrating a force sensor device according to a first embodiment. Fig. 2 is a cross-sectional perspective view illustrating the force sensor device according to the first embodiment. With reference to Figs. 1 and 2, the force sensor device 1 has a sensor chip 100 and a strain body 200. The force sensor device 1 is a multi-axis force sensor device mounted on, for example, the arms or fingers of a robot used in machine tools or the like.

[0012] The sensor chip 100 has a function of detecting displacement in a predetermined axial direction in up to six axes. The strain body 200 has a function of transmitting an applied force and / or moment to the sensor chip 100. In the following embodiments, as an example, a case where the sensor chip 100 detects six axes will be described, but the present invention is not limited thereto, and the sensor chip 100 can also be used in a case where it detects three axes, for example.

[0013] The flexure body 200 has a force receiving plate 210, a strain generating section 220, an input transmission section 230, and a cover plate 240. The strain generating section 220 is laminated on the force receiving plate 210, the input transmission section 230 is laminated on the strain generating section 220, and the cover plate 240 is laminated on the input transmission section 230, thereby forming the substantially cylindrical flexure body 200 as a whole. Note that since the function of the flexure body 200 is mainly performed by the strain generating section 220 and the input transmission section 230, the force receiving plate 210 and the cover plate 240 are provided as necessary.

[0014] In this embodiment, for convenience, in the force sensor device 1, the cover plate 240 side is referred to as the upper side or one side, and the force receiving plate 210 side is referred to as the lower side or the other side. Also, the surface of each part facing the cover plate 240 is referred to as one side or upper side, and the surface facing the force receiving plate 210 is referred to as the other side or lower side. However, the force sensor device 1 can be used upside down or placed at any angle. Also, a planar view refers to viewing an object from the normal direction (Z-axis direction) of the upper surface of the cover plate 240, and a planar shape refers to the shape of an object viewed from the normal direction (Z-axis direction) of the upper surface of the cover plate 240.

[0015] Fig. 3 is a top perspective view showing a state in which the sensor chip is attached to the input transmission section. Fig. 4 is a bottom perspective view showing a state in which the sensor chip is attached to the input transmission section. As shown in Figs. 3 and 4, the input transmission section 230 is provided with a housing section 235 that protrudes from the bottom surface of the input transmission section 230 toward the strain-generating section 220. The sensor chip 100 is fixed to the cover plate 240 side of the housing section 235.

[0016] Specifically, as described later, four second connection parts 235c (see FIGS. 22 to 24, etc., described later) protruding toward the cover plate 240 are arranged in the accommodation part 235. Each of the second connection parts 235c is connected to the lower surface of the force points 151 to 154 (see FIGS. 5 to 8, etc., described later) of the sensor chip 100.

[0017] The accommodation section 235 is recessed into the strain-flexing section 220. As described later, five columnar first connection sections 224 (see FIG. 21, etc., described later) protruding toward the input transmission section 230 are disposed on the strain-flexing section 220. Each of the first connection sections 224 is connected to the lower surface of the support sections 101-105 (see FIG. 5-8, etc., described later) of the sensor chip 100.

[0018] The sensor chip 100 and the strain body 200 will be described in detail below. In the following description, "parallel" includes cases where two straight lines or sides are in the range of 0°±10°. Furthermore, "perpendicular" or "orthogonal" includes cases where two straight lines or sides are in the range of 90°±10°. However, this does not apply unless there is a special explanation for each case. Furthermore, "center" or "middle" refers to the approximate center or center of an object, not the exact center or center. In other words, variations on the order of manufacturing errors are allowed. The same applies to point symmetry and line symmetry.

[0019] (Sensor chip 100) FIG. 5 is a perspective view of the sensor chip 100 viewed from above in the Z-axis direction. FIG. 6 is a plan view of the sensor chip 100 viewed from above in the Z-axis direction. FIG. 7 is a perspective view of the sensor chip 100 viewed from below in the Z-axis direction. FIG. 8 is a bottom view of the sensor chip 100 viewed from below in the Z-axis direction. In FIG. 8, for convenience, surfaces at the same height are shown with the same matte pattern. In this case, the direction parallel to one side of the upper surface of the sensor chip 100 is the X-axis direction, the direction perpendicular to the side is the Y-axis direction, and the thickness direction of the sensor chip 100 (the normal direction to the upper surface of the sensor chip 100) is the Z-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are mutually orthogonal.

[0020] 5 to 8 is a MEMS (Micro Electro Mechanical Systems) sensor chip capable of detecting up to six axes per chip, and is formed from a semiconductor substrate such as an SOI (Silicon On Insulator) substrate. The planar shape of the sensor chip 100 can be, for example, a rectangle (square or oblong) with sides of about 7000 μm.

[0021] The sensor chip 100 includes five columnar support parts 101-105. The planar shape of the support parts 101-105 may be, for example, a square of about 2000 μm on each side. The support parts 101-104 are disposed at the four corners of the rectangular sensor chip 100. The support part 105 is disposed in the center of the rectangular sensor chip 100. The support parts 101-104 are a representative example of a first support part according to the present invention, and the support part 105 is a representative example of a second support part according to the present invention.

[0022] Between supporting portion 101 and supporting portion 102, there is provided a frame portion 112 whose both ends are fixed to supporting portion 101 and supporting portion 102 (connecting adjacent supporting portions). Between supporting portion 102 and supporting portion 103, there is provided a frame portion 113 whose both ends are fixed to supporting portion 102 and supporting portion 103 (connecting adjacent supporting portions).

[0023] Between the supporting parts 103 and 104, there is provided a frame part 114 whose both ends are fixed to the supporting parts 103 and 104 (connecting adjacent supporting parts). Between the supporting parts 104 and 101, there is provided a frame part 111 whose both ends are fixed to the supporting parts 104 and 101 (connecting adjacent supporting parts).

[0024] In other words, the four frame portions 111, 112, 113, and 114 are formed in a frame shape, and the corners forming the intersections of the frame portions become the support portions 101, 102, 103, and 104.

[0025] An inner corner of support part 101 and an opposing corner of support part 105 are connected by connecting part 121. An inner corner of support part 102 and an opposing corner of support part 105 are connected by connecting part 122.

[0026] An inner corner of support part 103 and an opposing corner of support part 105 are connected by connecting part 123. An inner corner of support part 104 and an opposing corner of support part 105 are connected by connecting part 124.

[0027] That is, the sensor chip 100 has connecting portions 121 to 124 that connect the support portion 105 to the support portions 101 to 104. The connecting portions 121 to 124 are disposed obliquely with respect to the X-axis direction (Y-axis direction). That is, the connecting portions 121 to 124 are disposed non-parallel to the frame portions 111, 112, 113, and 114.

[0028] The supporting portions 101 to 105, the frame portions 111 to 114, and the connecting portions 121 to 124 can be formed, for example, from an active layer, a BOX layer, and a supporting layer of an SOI substrate, and each can have a thickness of, for example, about 400 μm to 600 μm.

[0029] The sensor chip 100 has four detection blocks B1 to B4. Each detection block has three T-shaped beam structures in which piezoresistance elements serving as strain detection elements are arranged. Here, the T-shaped beam structure refers to a structure including a first detection beam and a second detection beam extending from the center of the first detection beam in a direction perpendicular to the first detection beam.

[0030] Specifically, the detection block B1 includes T-shaped beam structures 131T1, 131T2, and 131T3. The detection block B2 includes T-shaped beam structures 132T1, 132T2, and 132T3. The detection block B3 includes T-shaped beam structures 133T1, 133T2, and 133T3. The detection block B4 includes T-shaped beam structures 134T1, 134T2, and 134T3. The beam structures are described in more detail below.

[0031] In the detection block B1, a first detection beam 131a is provided parallel to the side of the support portion 101 on the support portion 104 side at a predetermined interval so as to bridge the side of the frame portion 111 closer to the support portion 101 and the side of the connecting portion 121 closer to the support portion 105 in a plan view. In addition, a second detection beam 131b is provided, one end of which is connected to the center portion in the longitudinal direction of the first detection beam 131a, and which extends in a direction perpendicular to the longitudinal direction of the first detection beam 131a toward the support portion 104 side. The first detection beam 131a and the second detection beam 131b form a T-shaped beam structure 131T1.

[0032] In plan view, a first detection beam 131c is provided parallel to the side of the support portion 104 on the support portion 101 side at a predetermined interval so as to bridge the side of the frame portion 111 closer to the support portion 104 and the side of the connecting portion 124 closer to the support portion 105. In addition, a second detection beam 131d is provided having one end connected to the center portion in the longitudinal direction of the first detection beam 131c and extending in a direction perpendicular to the longitudinal direction of the first detection beam 131c toward the support portion 101 side. The first detection beam 131c and the second detection beam 131d form a T-shaped beam structure 131T2.

[0033] In plan view, a first detection beam 131e is provided parallel to the side of the support portion 105 on the frame portion 111 side at a predetermined interval so as to bridge the side of the connecting portion 121 closer to the support portion 105 and the side of the connecting portion 124 closer to the support portion 105. In addition, a second detection beam 131f is provided having one end connected to the center portion in the longitudinal direction of the first detection beam 131e and extending in a direction perpendicular to the longitudinal direction of the first detection beam 131e toward the frame portion 111 side. The first detection beam 131e and the second detection beam 131f form a T-shaped beam structure 131T3.

[0034] The other ends of the second detection beam 131b, the second detection beam 131d, and the second detection beam 131f are connected to each other to form a connection portion 141, and a force point 151 is provided on the lower surface side of the connection portion 141. The force point 151 is, for example, in the shape of a rectangular prism. The T-shaped beam structures 131T1, 131T2, and 131T3, the connection portion 141, and the force point 151 constitute a detection block B1.

[0035] In the detection block B1, the first detection beam 131a, the first detection beam 131c, and the second detection beam 131f are parallel to each other, and the second detection beams 131b and 131d are parallel to the first detection beam 131e. The thickness of each detection beam in the detection block B1 may be, for example, about 30 μm to 50 μm.

[0036] In the detection block B2, a first detection beam 132a is provided parallel to the side of the support portion 102 on the support portion 101 side at a predetermined interval so as to bridge the side of the frame portion 112 closer to the support portion 102 and the side of the connecting portion 122 closer to the support portion 105 in a plan view. In addition, a second detection beam 132b is provided, one end of which is connected to the center portion in the longitudinal direction of the first detection beam 132a, and which extends in a direction perpendicular to the longitudinal direction of the first detection beam 132a toward the support portion 101 side. The first detection beam 132a and the second detection beam 132b form a T-shaped beam structure 132T1.

[0037] In plan view, a first detection beam 132c is provided parallel to the side of the support portion 101 on the support portion 102 side at a predetermined interval so as to bridge the side of the frame portion 112 closer to the support portion 101 and the side of the connecting portion 121 closer to the support portion 105. In addition, a second detection beam 132d is provided, one end of which is connected to the center portion in the longitudinal direction of the first detection beam 132c, and which extends in a direction perpendicular to the longitudinal direction of the first detection beam 132c toward the support portion 102 side. The first detection beam 132c and the second detection beam 132d form a T-shaped beam structure 132T2.

[0038] In plan view, a first detection beam 132e is provided parallel to the side of the support portion 105 on the frame portion 112 side at a predetermined interval so as to bridge the side of the connecting portion 122 closer to the support portion 105 and the side of the connecting portion 121 closer to the support portion 105. In addition, a second detection beam 132f is provided, one end of which is connected to the center portion in the longitudinal direction of the first detection beam 132e, and which extends in a direction perpendicular to the longitudinal direction of the first detection beam 132e toward the frame portion 112 side. The first detection beam 132e and the second detection beam 132f form a T-shaped beam structure 132T3.

[0039] The other ends of the second detection beam 132b, the second detection beam 132d, and the second detection beam 132f are connected to each other to form a connection portion 142, and a force point 152 is provided on the lower surface side of the connection portion 142. The force point 152 is, for example, in the shape of a rectangular prism. The T-shaped beam structures 132T1, 132T2, and 132T3, the connection portion 142, and the force point 152 constitute a detection block B2.

[0040] In the detection block B2, the first detection beam 132a, the first detection beam 132c, and the second detection beam 132f are parallel to each other, and the second detection beams 132b and 132d and the first detection beam 132e are parallel to each other. The thickness of each detection beam of the detection block B2 may be, for example, about 30 μm to 50 μm.

[0041] In the detection block B3, a first detection beam 133a is provided parallel to the side of the support portion 103 on the support portion 102 side at a predetermined interval so as to bridge the side of the frame portion 113 closer to the support portion 103 and the side of the connecting portion 123 closer to the support portion 105 in a plan view. In addition, a second detection beam 133b is provided, one end of which is connected to the center portion in the longitudinal direction of the first detection beam 133a and which extends in a direction perpendicular to the longitudinal direction of the first detection beam 133a toward the support portion 102 side. The first detection beam 133a and the second detection beam 133b form a T-shaped beam structure 133T1.

[0042] In plan view, a first detection beam 133c is provided parallel to the side of the support portion 102 on the support portion 103 side of the support portion 102 at a predetermined interval so as to bridge the side of the frame portion 113 closer to the support portion 102 and the side of the connecting portion 122 closer to the support portion 105. In addition, a second detection beam 133d is provided, one end of which is connected to the center portion in the longitudinal direction of the first detection beam 133c, and which extends in a direction perpendicular to the longitudinal direction of the first detection beam 133c toward the support portion 103 side. The first detection beam 133c and the second detection beam 133d form a T-shaped beam structure 133T2.

[0043] In plan view, a first detection beam 133e is provided parallel to the side of the support portion 105 on the frame portion 113 side at a predetermined interval so as to bridge the side of the connecting portion 123 closer to the support portion 105 and the side of the connecting portion 122 closer to the support portion 105. In addition, a second detection beam 133f is provided, one end of which is connected to the center portion in the longitudinal direction of the first detection beam 133e, and which extends in a direction perpendicular to the longitudinal direction of the first detection beam 133e toward the frame portion 113 side. The first detection beam 133e and the second detection beam 133f form a T-shaped beam structure 133T3.

[0044] The other ends of the second detection beam 133b, the second detection beam 133d, and the second detection beam 133f are connected to each other to form a connection portion 143, and a force point 153 is provided on the lower surface side of the connection portion 143. The force point 153 is, for example, in the shape of a rectangular prism. The T-shaped beam structures 133T1, 133T2, and 133T3, the connection portion 143, and the force point 153 constitute a detection block B3.

[0045] In the detection block B3, the first detection beam 133a, the first detection beam 133c, and the second detection beam 133f are parallel to each other, and the second detection beams 133b and 133d are parallel to the first detection beam 133e. The thickness of each detection beam of the detection block B3 may be, for example, about 30 μm to 50 μm.

[0046] In the detection block B4, a first detection beam 134a is provided parallel to the side of the support portion 104 on the support portion 103 side at a predetermined interval so as to bridge the side of the frame portion 114 closer to the support portion 104 and the side of the connecting portion 124 closer to the support portion 105 in a plan view. In addition, a second detection beam 134b is provided, one end of which is connected to the center portion in the longitudinal direction of the first detection beam 134a and which extends in a direction perpendicular to the longitudinal direction of the first detection beam 134a toward the support portion 103 side. The first detection beam 134a and the second detection beam 134b form a T-shaped beam structure 134T1.

[0047] In plan view, a first detection beam 134c is provided parallel to the side of the support portion 103 on the support portion 104 side at a predetermined interval so as to bridge the side of the frame portion 114 closer to the support portion 103 and the side of the connecting portion 123 closer to the support portion 105. In addition, a second detection beam 134d is provided, one end of which is connected to the center portion in the longitudinal direction of the first detection beam 134c, and which extends in a direction perpendicular to the longitudinal direction of the first detection beam 134c toward the support portion 104 side. The first detection beam 134c and the second detection beam 134d form a T-shaped beam structure 134T2.

[0048] In plan view, a first detection beam 134e is provided parallel to the side of the support portion 105 on the frame portion 114 side of the support portion 105 at a predetermined interval so as to bridge the side of the connection portion 124 closer to the support portion 105 and the side of the connection portion 123 closer to the support portion 105. In addition, a second detection beam 134f is provided, one end of which is connected to the center portion in the longitudinal direction of the first detection beam 134e, and which extends in a direction perpendicular to the longitudinal direction of the first detection beam 134e toward the frame portion 114 side. The first detection beam 134e and the second detection beam 134f form a T-shaped beam structure 134T3.

[0049] The other ends of the second detection beam 134b, the second detection beam 134d, and the second detection beam 134f are connected to each other to form a connection portion 144, and a force point 154 is provided on the lower surface side of the connection portion 144. The force point 154 is, for example, in the shape of a rectangular prism. The T-shaped beam structures 134T1, 134T2, and 134T3, the connection portion 144, and the force point 154 constitute a detection block B4.

[0050] In the detection block B4, the first detection beam 134a, the first detection beam 134c, and the second detection beam 134f are parallel to each other, and the second detection beams 134b and 134d are parallel to the first detection beam 134e. The thickness of each detection beam of the detection block B4 may be, for example, about 30 μm to 50 μm.

[0051] Thus, the sensor chip 100 has four detection blocks (detection blocks B1 to B4). Each detection block is disposed in an area surrounded by an adjacent support part among the support parts 101 to 104, a frame part and a connecting part connecting the adjacent support parts, and the support part 105. In a plan view, each detection block can be disposed, for example, point-symmetrically with respect to the center of the sensor chip.

[0052] Each detection block has three T-shaped beam structures. In each detection block, the three T-shaped beam structures include, in a plan view, two T-shaped beam structures in which first detection beams are arranged in parallel with a connection portion therebetween, and one T-shaped beam structure including a first detection beam arranged in parallel with a second detection beam of the two T-shaped beam structures. The first detection beam of the one T-shaped beam structure is arranged between the connection portion and the support portion 105.

[0053] For example, in the detection block B1, the three sets of T-shaped beam structures include T-shaped beam structures 131T1 and 131T2 in which the first detection beam 131a and the first detection beam 131c are arranged in parallel with each other across the connection portion 141 in a plan view, and a T-shaped beam structure 131T3 including a first detection beam 131e arranged in parallel with the second detection beams 131b and 131d of the T-shaped beam structures 131T1 and 131T2. The first detection beam 131e of the T-shaped beam structure 131T3 is arranged between the connection portion 141 and the support portion 105. The detection blocks B2 to B4 also have a similar structure.

[0054] The force points 151-154 are points to which an external force is applied, and can be formed, for example, from the BOX layer and support layer of an SOI substrate. The lower surfaces of the force points 151-154 are approximately flush with the lower surfaces of the support portions 101-105.

[0055] In this way, by inputting force or displacement from the four force points 151 to 154, different deformations of the beam can be obtained for each type of force, and a sensor with good six-axis separation can be realized. The number of force points is the same as the number of displacement input points of the combined strain generating body.

[0056] In the sensor chip 100, from the viewpoint of suppressing stress concentration, it is preferable that the portions forming the interior angles have an R-shape.

[0057] Supporting parts 101-105 of sensor chip 100 are connected to the non-movable parts of flexure body 200, and force points 151-154 are connected to the movable parts of flexure body 200. However, even if the relationship between movable and non-movable is reversed, it still functions as a force sensor device. In other words, supporting parts 101-105 of sensor chip 100 may be connected to the movable parts of flexure body 200, and force points 151-154 may be connected to the non-movable parts of flexure body 200.

[0058] Fig. 9 is a diagram explaining the symbols indicating the forces and moments acting on each axis. As shown in Fig. 9, the force in the X-axis direction is Fx, the force in the Y-axis direction is Fy, and the force in the Z-axis direction is Fz. Also, the moment of rotation about the X-axis is Mx, the moment of rotation about the Y-axis is My, and the moment of rotation about the Z-axis is Mz.

[0059] Fig. 10 is a diagram illustrating an example of the arrangement of piezoresistance elements of the sensor chip 100. Fig. 11 is a partial enlarged view of a set of detection blocks of the sensor chip shown in Fig. 10. As shown in Figs. 10 and 11, piezoresistance elements are arranged at predetermined positions of each detection block corresponding to four force points 151 to 154. The arrangement of the piezoresistance elements in the other detection blocks shown in Fig. 10 is similar to the arrangement of the piezoresistance elements in one detection block shown in Fig. 11.

[0060] 5 to 8, 10, and 11, in a detection block B1 having a connection portion 141 and a force point 151, the piezoresistive element MzR1' is disposed on the first detection beam 131a on a side closer to the second detection beam 131b in a portion located between the second detection beam 131b and the first detection beam 131e. The piezoresistive element FxR3 is disposed on the first detection beam 131a on a side closer to the first detection beam 131e in a portion located between the second detection beam 131b and the first detection beam 131e. The piezoresistive element MxR1 is disposed on the second detection beam 131b on a side closer to the connection portion 141.

[0061] In addition, the piezoresistive element MzR2' is disposed on the first detection beam 131c on a side closer to the second detection beam 131d in a portion located between the second detection beam 131d and the first detection beam 131e. The piezoresistive element FxR1 is disposed on the first detection beam 131c on a side closer to the first detection beam 131e in a portion located between the second detection beam 131d and the first detection beam 131e. The piezoresistive element MxR2 is disposed on the second detection beam 131d on a side closer to the connection portion 141.

[0062] Moreover, the piezoresistive element FzR1' is disposed on a side of the second detection beam 131f closer to the connection portion 141. The piezoresistive element FzR2' is disposed on a side of the second detection beam 131f closer to the first detection beam 131e. Note that the piezoresistive elements MzR1', FxR3, MxR1, MzR2', FxR1, and MxR2 are disposed at positions offset from the longitudinal center of each detection beam.

[0063] In the detection block B2 having the connection portion 142 and the force point 152, the piezoresistive element MzR4 is disposed on the first detection beam 132a on a side closer to the second detection beam 132b in a portion located between the second detection beam 132b and the first detection beam 132e. The piezoresistive element FyR3 is disposed on the first detection beam 132a on a side closer to the first detection beam 132e in a portion located between the second detection beam 132b and the first detection beam 132e. The piezoresistive element MyR4 is disposed on the second detection beam 132b on a side closer to the connection portion 142.

[0064] The piezoresistive element MzR3 is disposed on the first detection beam 132c on a side closer to the second detection beam 132d in a portion located between the second detection beam 132d and the first detection beam 132e. The piezoresistive element FyR1 is disposed on the first detection beam 132c on a side closer to the first detection beam 132e in a portion located between the second detection beam 132d and the first detection beam 132e. The piezoresistive element MyR3 is disposed on the second detection beam 132d on a side closer to the connection portion 142.

[0065] Furthermore, the piezoresistive element FzR4 is disposed on the second detection beam 132f on a side closer to the connection portion 142. The piezoresistive element FzR3 is disposed on the second detection beam 132f on a side closer to the first detection beam 132e. Note that the piezoresistive elements MzR4, FyR3, MyR4, MzR3, FyR1, and MyR3 are disposed at positions offset from the longitudinal center of each detection beam.

[0066] In the detection block B3 having the connection portion 143 and the force point 153, the piezoresistive element MzR4' is disposed on the first detection beam 133a on a side closer to the second detection beam 133b in a portion located between the second detection beam 133b and the first detection beam 133e. The piezoresistive element FxR2 is disposed on the first detection beam 133a on a side closer to the first detection beam 133e in a portion located between the second detection beam 133b and the first detection beam 133e. The piezoresistive element MxR4 is disposed on the second detection beam 133b on a side closer to the connection portion 143.

[0067] The piezoresistive element MzR3' is disposed on the first detection beam 133c on a side closer to the second detection beam 133d in a portion located between the second detection beam 133d and the first detection beam 133e. The piezoresistive element FxR4 is disposed on the first detection beam 133c on a side closer to the first detection beam 133e in a portion located between the second detection beam 133d and the first detection beam 133e. The piezoresistive element MxR3 is disposed on the second detection beam 133d on a side closer to the connection portion 143.

[0068] Moreover, the piezoresistive element FzR4' is disposed on the second detection beam 133f on a side closer to the connection portion 143. The piezoresistive element FzR3' is disposed on the second detection beam 133f on a side closer to the first detection beam 133e. Note that the piezoresistive elements MzR4', FxR2, MxR4, MzR3', FxR4, and MxR3 are disposed at positions offset from the longitudinal center of each detection beam.

[0069] In the detection block B4 having the connection portion 144 and the force point 154, the piezoresistive element MzR1 is disposed on the first detection beam 134a on a side closer to the second detection beam 134b in a portion located between the second detection beam 134b and the first detection beam 134e. The piezoresistive element FyR2 is disposed on the first detection beam 134a on a side closer to the first detection beam 134e in a portion located between the second detection beam 134b and the first detection beam 134e. The piezoresistive element MyR1 is disposed on the second detection beam 134b on a side closer to the connection portion 144.

[0070] The piezoresistive element MzR2 is disposed on the first detection beam 134c on a side closer to the second detection beam 134d in a portion located between the second detection beam 134d and the first detection beam 134e. The piezoresistive element FyR4 is disposed on the first detection beam 134c on a side closer to the first detection beam 134e in a portion located between the second detection beam 134d and the first detection beam 134e. The piezoresistive element MyR2 is disposed on the second detection beam 134d on a side closer to the connection portion 144.

[0071] Moreover, the piezoresistive element FzR1 is disposed on a side of the second detection beam 134f closer to the connection portion 144. The piezoresistive element FzR2 is disposed on a side of the second detection beam 134f closer to the first detection beam 134e. The piezoresistive elements MzR1, FyR2, MyR1, MzR2, FyR4, and MyR2 are disposed at positions offset from the longitudinal center of each detection beam.

[0072] In this way, multiple piezoresistance elements are arranged separately in each detection block in the sensor chip 100. This makes it possible to detect forces or moments in predetermined axial directions along up to six axes based on changes in output of multiple piezoresistance elements arranged on predetermined beams in response to inputs applied to the force points 151 to 154.

[0073] In addition to the piezoresistance elements used for detecting strain, dummy piezoresistance elements may be arranged in the sensor chip 100. The dummy piezoresistance elements are used to adjust the balance of the stress applied to the detection beam and the resistance of the bridge circuit. For example, all the piezoresistance elements including the piezoresistance elements used for detecting strain are arranged so as to be point-symmetric with respect to the center of the support part 105.

[0074] In the sensor chip 100, a plurality of piezoresistance elements for detecting displacement in the X-axis direction and the Y-axis direction are arranged on a first detection beam constituting a T-shaped beam structure. A plurality of piezoresistance elements for detecting displacement in the Z-axis direction are arranged on a second detection beam constituting the T-shaped beam structure. A plurality of piezoresistance elements for detecting moment in the Z-axis direction are arranged on the first detection beam constituting the T-shaped beam structure. A plurality of piezoresistance elements for detecting moment in the X-axis direction and the Y-axis direction are arranged on the second detection beam constituting the T-shaped beam structure.

[0075] Here, the piezoresistive elements FxR1-FxR4 detect a force Fx, the piezoresistive elements FyR1-FyR4 detect a force Fy, the piezoresistive elements FzR1-FzR4 and FzR1'-FzR4' detect a force Fz, the piezoresistive elements MxR1-MxR4 detect a moment Mx, the piezoresistive elements MyR1-MyR4 detect a moment My, and the piezoresistive elements MzR1-MzR4 and MzR1'-MzR4' detect a moment Mz.

[0076] In this way, in the sensor chip 100, a plurality of piezoresistance elements are arranged separately in each detection block. This makes it possible to detect a displacement in a predetermined axial direction in up to six axes based on a change in output of a plurality of piezoresistance elements arranged in a predetermined beam according to the direction (axial direction) of the force or displacement applied (transmitted) to the force points 151 to 154. In addition, by varying the thickness and width of each detection beam, it is possible to make the detection sensitivity uniform or to adjust the detection sensitivity to be improved.

[0077] It is also possible to reduce the number of piezoresistance elements and form a sensor chip that detects displacement in five or fewer predetermined axial directions.

[0078] In the sensor chip 100, the force and moment can be detected, for example, by using a detection circuit described below. An example of a detection circuit using each piezoresistance element is shown in Fig. 12 and Fig. 13. In Fig. 12 and Fig. 13, the numbers enclosed in squares indicate external output terminals. For example, No. 1 is a power supply terminal for the Fx-axis, Fy-axis, and Fz-axis, No. 2 is a negative Fx-axis output terminal, No. 3 is a GND terminal for the Fx-axis, and No. 4 is a positive Fx-axis output terminal. No. 19 is a negative Fy-axis output terminal, No. 20 is a GND terminal for the Fy-axis, and No. 21 is a positive Fy-axis output terminal. No. 22 is a negative Fz-axis output terminal, No. 23 is a GND terminal for the Fz-axis, and No. 24 is a positive Fz-axis output terminal.

[0079] Additionally, No. 9 is the Mx-axis output negative terminal, No. 10 is the Mx-axis GND terminal, and No. 11 is the Mx-axis output positive terminal. No. 12 is the power supply terminal for the Mx, My, and Mz axes. No. 13 is the My-axis output negative terminal, No. 14 is the My-axis GND terminal, and No. 15 is the My-axis output positive terminal. No. 16 is the Mz-axis output negative terminal, No. 17 is the Mz-axis GND terminal, and No. 18 is the Mz-axis output positive terminal.

[0080] Next, the deformation of the detection beam will be described. FIG. 14 is a diagram for explaining the Fx input. FIG. 15 is a diagram for explaining the Fy input. As shown in FIG. 14, when the input from the flexure body 200 on which the sensor chip 100 is mounted is Fx, all of the four force points 151 to 154 tend to move in the same direction (rightward in the example of FIG. 14). Similarly, as shown in FIG. 15, when the input from the flexure body 200 on which the sensor chip 100 is mounted is Fy, all of the four force points 151 to 154 tend to move in the same direction (upward in the example of FIG. 15). That is, although there are four detection blocks in the sensor chip 100, in each detection block, all of the force points move in the same direction in response to displacement in the X-axis direction and displacement in the Y-axis direction.

[0081] Figure 16 shows the simulation results when an Fx input is applied to the sensor chip. When an Fx input is applied as shown by the arrow in Figure 14, each detection beam is deformed as shown in Figure 16. In particular, it can be seen that the first detection beam (the beam forming the horizontal line of the T) in the T-shaped beam structure in each detection block is significantly deformed.

[0082] In the sensor chip 100, the first detection beams of the T-shaped beam structure have one or more first detection beams perpendicular to the input displacement direction, and the first detection beams perpendicular to the input displacement direction can accommodate large deformation as shown in Fig. 16. In Fig. 16, the first detection beams perpendicular to the input displacement direction are first detection beams 131a, 131c, 132e, 133a, 133c, and 134e shown in Fig. 6 and the like.

[0083] The beams used to detect the Fx input are first detection beams 131a, 131c, 133a, and 133c, all of which are first detection beams with a T-shaped beam structure located a certain distance away from the point of force. The beams used to detect the Fy input are first detection beams 132a, 132c, 134a, and 134c, all of which are first detection beams with a T-shaped beam structure located a certain distance away from the point of force.

[0084] In the case of the Fx input and the Fy input, the first detection beam of the T-shaped beam structure in which the piezoresistance element is arranged is largely deformed, so that the input force can be effectively detected. Also, since the beams not used for input detection are designed to be largely deformable following the displacement of the Fx input and the Fy input, the detection beam will not be destroyed even if there is a large Fx input and / or Fy input.

[0085] In addition, in the conventional sensor chip, since there is a beam that cannot be significantly deformed in response to the Fx input and / or Fy input, there is a risk that the detection beam that cannot be deformed will be destroyed in the case of a large Fx input and / or Fy input. The sensor chip 100 can suppress such a problem. That is, the sensor chip 100 can improve the destruction resistance of the beam against displacement in various directions.

[0086] In this way, the sensor chip 100 has one or more first detection beams perpendicular to the displacement direction of the input, and the first detection beams perpendicular to the displacement direction of the input can be greatly deformed. Therefore, the Fx input and the Fy input can be effectively detected, and the detection beams are not broken even if there is a large Fx input and / or Fy input. As a result, the sensor chip 100 can also handle a large rating, and the measurement range and load resistance can be improved. For example, the sensor chip 100 can have a rating of 500 N, which is about 10 times that of the conventional sensor chip.

[0087] In addition, the T-shaped beam structure in each detection block, which is connected in three directions from the force point, deforms differently depending on the input, making it possible to detect multi-axial forces with good separation.

[0088] In addition, because the beam is T-shaped, there are many paths from the beam to the frame and connecting parts, making it easy to route wiring to the outer periphery of the sensor chip, improving layout freedom.

[0089] Fig. 17 shows the simulation results when Mz input is applied to the sensor chip. As shown in Fig. 17, the first detection beams 131a, 131c, 132a, 132c, 133a, 133c, 134a, and 134c arranged opposite each force point are significantly deformed by the moment in the Z-axis direction. Therefore, piezoresistance elements can be arranged on some or all of these first detection beams.

[0090] Fig. 18 shows the simulation results when Fz input is applied to the sensor chip. Fig. 19 is a partial perspective view corresponding to Fig. 18. As shown in Fig. 18 and Fig. 19, with respect to the displacement in the Z-axis direction, mainly the second detection beams 131b, 131d, 131f, 132b, 132d, 132f, 133b, 133d, 133f, 134b, 134d, and 134f directly connected to each point of force are largely deformed. Therefore, piezoresistance elements can be disposed on some or all of these second detection beams.

[0091] (Strain body 200) 1 and 2, the strain generating body 200 has a force receiving plate 210, a strain generating portion 220, an input transmitting portion 230, and a cover plate 240. Here, each component of the strain generating body 200 will be described.

[0092] FIG. 20 is a perspective view illustrating a force receiving plate constituting a strain generating body. As shown in FIG. 20, the force receiving plate 210 is a member having a substantially disk shape as a whole, and is a member to which a force or moment is input from an object to be measured. The force receiving plate 210 has an outer frame portion 211 having a substantially ring shape in a plan view, a central portion 212 having a substantially circular shape in a plan view and disposed inside the outer frame portion 211 and spaced apart from the outer frame portion 211, and a plurality of beam structures 213 bridging the outer frame portion 211 and the central portion 212. Even when the strength of the force receiving plate 210 is increased by the beam structure 213 and a force or moment is input from an object to be measured, the force receiving plate 210 itself is hardly deformed, and deformation (displacement) is transmitted without loss to the strain generating portion 220 connected at the central portion 212. A through hole 218 is provided in a portion protruding from the inside of the outer frame portion 211 toward the beam structure 213. The through holes 218 can be used, for example, when fastening the force receiving plate 210 to an object to be measured with screws.

[0093] Fig. 21 is a perspective view illustrating a strain-flexing part that constitutes the strain body. As shown in Fig. 21, the strain-flexing part 220 is a member that is generally approximately disk-shaped, and is a part that receives a force from the force-receiving plate 210 and deforms.

[0094] The strain-flexing portion 220 has an outer frame portion 221 that is substantially ring-shaped in a planar view, a central portion 222 that is substantially circular in a planar view and disposed inside the outer frame portion 221 at a distance from the outer frame portion 221, and a plurality of beam structures 223 that bridge the outer frame portion 221 and the central portion 222. The plurality of beam structures 223 are disposed, for example, point-symmetrically with respect to the center of the strain-flexing portion 220. There are, for example, four beam structures 223. Each beam structure 223 is, for example, T-shaped including a first beam and a second beam extending from the central portion of the first beam in a direction perpendicular to the first beam, and both ends of the first beam are connected to the outer frame portion 221, and an end of the second beam is connected to the central portion 222.

[0095] The central portion 222 is formed thinner than the outer frame portion 221, and the beam structure 223 is formed even thinner than the central portion 222. The upper surface of the central portion 222 and the upper surface of the beam structure 223 are substantially flush with each other and are located lower than the upper surface of the outer frame portion 221. The lower surface of the central portion 222 protrudes slightly from the lower surface of the outer frame portion 221. The lower surface of the beam structure 223 is located higher than the lower surface of the outer frame portion 221 and the lower surface of the central portion 222. Only the beam structure 223 and the central portion 222 are deformed by receiving a force from the force receiving plate 210, and the outer frame portion 221 is not deformed. However, the central portion 222 only moves following the deformation of the beam structure 223, and the central portion 222 itself is not deformed.

[0096] A groove 220x is formed on the surface of the central portion 222 facing the input transmission portion 230. The groove 220x has a shape in which a square groove in a plan view and a cross-shaped groove in which two elongated grooves longer than one side of the square intersect at right angles are overlapped with their centers aligned. The square groove in a plan view and the cross-shaped groove in a plan view have the same depth.

[0097] Outside the cross-shaped groove, at the four corners of the square groove and at the center of the square groove, five columnar first connection parts 224 protruding toward the input transmission part 230 are arranged so as not to come into contact with the inner wall of the groove 220x. The first connection parts 224 are parts that are connected to the support parts 101 to 105 of the sensor chip 100. The upper surface of each of the first connection parts 224 is substantially flush and is located lower than the upper surface of the central part 222 and the upper surface of the beam structure 223. The outer frame part 221 is provided with a through hole 228. The through hole 228 can be used, for example, when fastening the strain-flexing part 220, the input transmission part 230, and the cover plate 240 to a fixed side (the side of a robot, etc.) with a screw.

[0098] In addition, since a space is provided on the upper surface side of the central portion 222, a circuit board or the like on which electronic components such as connectors and semiconductor elements are mounted may be placed on the upper surface side of the central portion 222 so as not to protrude from the upper surface of the outer frame portion 221.

[0099] Fig. 22 is a perspective view of the upper surface side illustrating an input transmission section constituting the flexure body. Fig. 23 is a perspective view of the lower surface side illustrating an input transmission section constituting the flexure body. Fig. 24 is a side view illustrating an input transmission section constituting the flexure body. As shown in Figs. 22 to 24, the input transmission section 230 is a substantially disc-shaped member overall, and is a section that transmits the deformation (input) of the strain-generating section 220 to the sensor chip 100.

[0100] The input transmission section 230 has an outer frame section 231 that is substantially ring-shaped in a plan view, a central section 232 that is spaced apart from the outer frame section 231 and disposed inside the outer frame section 231, and a plurality of beam structures 233 that bridge the outer frame section 231 and the central section 232. The plurality of beam structures 233 are disposed, for example, point-symmetrically with respect to the center of the input transmission section 230. There are, for example, four beam structures 233. Each beam structure 233 is, for example, I-shaped.

[0101] Central portion 232 has an inner frame portion 234 that is substantially ring-shaped in a plan view and connects to beam structure 233, and a substantially cross-shaped accommodation portion 235 that extends from the lower surface of inner frame portion 234 toward strain-flexing portion 220. Accommodation portion 235 has four vertical support portions 235a that extend vertically from the lower surface of inner frame portion 234 toward strain-flexing portion 220, and four horizontal support portions 235b that extend horizontally from the lower ends of vertical support portions 235a and intersect at the center of inner frame portion 234.

[0102] Beam structure 233 and inner frame portion 234 are formed thinner than outer frame portion 231. The upper surfaces of beam structure 233 and inner frame portion 234 are located lower than the upper surface of outer frame portion 231. The lower surface of outer frame portion 231, the lower surface of beam structure 233, and the lower surface of inner frame portion 234 are approximately flush with each other. None of the parts of input transmission portion 230 are deformed by the force or moment they receive.

[0103] In a plan view, the four vertical support portions 235a and the four horizontal support portions 235b are arranged point-symmetrically with respect to the center of the input transmission portion 230. In a plan view, the longitudinal direction of each horizontal support portion 235b does not coincide with the longitudinal direction of each beam structure 233. For example, in a plan view, the longitudinal direction of each horizontal support portion 235b and the longitudinal direction of each beam structure 233 are shifted by 45 degrees.

[0104] A groove 235x is provided near the center of the approximately cross-shaped housing portion 235, and four second connection parts 235c protruding toward the cover plate 240 side are arranged on the bottom surface of the groove 235x so as not to come into contact with the inner wall of the groove 235x. Each second connection part 235c is approximately located on a line that divides each horizontal support part 235b in half in the longitudinal direction. The second connection parts 235c are parts that are connected to the force points 151 to 154 of the sensor chip 100. A through hole 238 is provided in the outer frame part 231. The through hole 238 can be used, for example, when fastening the strain generating part 220, the input transmission part 230, and the cover plate 240 to a fixed side (the side of a robot, etc.) with a screw.

[0105] In addition, since a space is provided on the upper surface side of the beam structure 233, a circuit board or the like on which electronic components such as connectors and semiconductor elements are mounted may be arranged on the upper surface side of the beam structure 233 so as not to protrude from the upper surface of the outer frame portion 231.

[0106] Fig. 25 is a perspective view illustrating a cover plate constituting the strain generating body. As shown in Fig. 25, the cover plate 240 is a member that is generally disk-shaped and protects the internal components (sensor chip 100, etc.). The cover plate 240 is formed thinner than the force receiving plate 210, the strain generating part 220, and the input transmitting part 230. The cover plate 240 is provided with a through hole 248. The through hole 248 can be used, for example, when fastening the strain generating part 220, the input transmitting part 230, and the cover plate 240 to a fixed side (the side of a robot, etc.) with a screw.

[0107] The materials for the force receiving plate 210, the strain generating part 220, the input transmission part 230, and the cover plate 240 may be, for example, a hard metal material such as SUS (stainless steel). Of these, it is preferable to use SUS630, which is particularly hard and has high mechanical strength. Of the members constituting the strain generating body 200, it is particularly desirable that the force receiving plate 210, the strain generating part 220, and the input transmission part 230 are firmly connected or have an integral structure. Methods for connecting the force receiving plate 210, the strain generating part 220, and the input transmission part 230 include screw fastening, welding, etc., but any method must be able to fully withstand the force and moment input to the strain generating body 200.

[0108] In this embodiment, as an example, the force receiving plate 210, the strain generating part 220, and the input transmitting part 230 are produced by metal powder injection molding, and then they are combined and sintered again to form a diffusion bond. The diffusion bonded force receiving plate 210, the strain generating part 220, and the input transmitting part 230 can obtain a necessary and sufficient bonding strength. After the sensor chip 100 and other internal parts are mounted, the cover plate 240 may be fastened to the input transmitting part 230 by, for example, a screw.

[0109] In the strain-generating body 200, when a force or moment is applied to the force-receiving plate 210, the force or moment is transmitted to the central portion 222 of the strain-generating part 220 connected to the force-receiving plate 210, and deformation according to the input occurs in the four beam structures 223. At this time, the outer frame portion 221 and the input transmission portion 230 of the strain-generating part 220 do not deform.

[0110] That is, in the strain-generating body 200, the force-receiving plate 210 and the central portion 222 and beam structure 223 of the strain-generating part 220 are movable parts that deform when subjected to a force or moment in a predetermined axial direction, and the outer frame part 221 of the strain-generating part 220 is a non-movable part that does not deform when subjected to a force or moment. Also, the input transmission part 230 that is joined to the outer frame part 221 of the strain-generating part 220, which is a non-movable part, is a non-movable part that does not deform when subjected to a force or moment, and the cover plate 240 that is joined to the input transmission part 230 is also a non-movable part that does not deform when subjected to a force or moment.

[0111] When the strain body 200 is used in the force sensor device 1, the support parts 101-105 of the sensor chip 100 are connected to a first connection part 224 provided in the center part 222, which is a movable part. Moreover, the force points 151-154 of the sensor chip 100 are connected to a second connection part 235c provided in the accommodation part 235, which is a non-movable part. Therefore, in the sensor chip 100, the force points 151-154 do not move, and each detection beam is deformed through the support parts 101-105.

[0112] However, the configuration may also be such that the force points 151-154 of the sensor chip 100 are connected to a first connection portion 224 provided in the central portion 222, which is the movable portion, and the support portions 101-105 of the sensor chip 100 are connected to a second connection portion 235c provided in the accommodating portion 235, which is the non-movable portion.

[0113] That is, the sensor chip 100 that can be accommodated in the accommodation portion 235 has the support portions 101-105 and the force points 151-154 whose relative positions change when subjected to a force or moment. In the strain body 200, the central portion 222, which is the movable portion, has a first connection portion 224 that extends toward the input transmission portion 230 and is connected to one of the support portions 101-105 and the force points 151-154. The accommodation portion 235 also has a second connection portion 235c that is connected to the other of the support portions 101-105 and the force points 151-154.

[0114] Fig. 26 shows the simulation results when an Fx input is applied to the strain-flexing part. Fig. 27 shows the simulation results when an Mz input is applied to the strain-flexing part. As shown in Fig. 26 and Fig. 27, it can be seen that in both cases, the outer frame part 221 of the strain-flexing part 220 does not deform, and the four T-shaped beam structures 223 are deformed. The same is true for other inputs.

[0115] In this way, the flexure body 200 converts the input force or moment into a displacement and transmits it to the mounted sensor chip 100. In conventional flexure bodies that aimed to achieve the same function, the structure that received the force or moment and the structure that transmitted the displacement were integrated or closely arranged. Therefore, there was a strong trade-off between the displacement and the load capacity, and it was particularly difficult to achieve a large load capacity.

[0116] In the strain-generating body 200, the strain-generating part 220 that receives forces and moments and the input transmission part 230 that transmits displacement to the sensor chip 100 are separate structures, making it possible to achieve both high load resistance and displacement.

[0117] First Modification of the First Embodiment In Modification 1 of the first embodiment, an example of a sensor chip having a structure different from that of the first embodiment is shown. Note that in Modification 1 of the first embodiment, the description of the same components as those of the already described embodiments may be omitted.

[0118] Fig. 28 is a plan view of the sensor chip 100A viewed from above in the Z-axis direction. As shown in Fig. 28, the structure of the detection beams of the sensor chip 100A is similar to that of the sensor chip 100 (see Fig. 6, etc.). However, the shape of the space around the detection beams is different from that of the sensor chip 100. That is, in the sensor chip 100A, the opening width of the space in plan view is uniform on both sides of each detection beam.

[0119] Generally, the beam structure of the sensor chip is formed from a silicon wafer by a semiconductor process, and deep digging is performed by dry etching. If the opening width of the etching area separated by the detection beam is large and not uniform, as in the shape of the sensor chip 100, there is a concern that the processing difficulty will increase and the processing quality will deteriorate.

[0120] In the sensor chip 100A, an etching region is formed in the shape of a narrow slit with a uniform opening width on both sides of each detection beam. This reduces the processing difficulty when digging deep by dry etching, and improves the processing quality. The four circular openings in FIG. 28 are escape portions that prevent the sensor chip 100A from contacting the strain body 200 when mounting the sensor chip 100A on the strain body 200. Therefore, when only the efficiency of dry etching is considered, the four circular openings do not need to be provided.

[0121] Fig. 29 is a partial plan view of the sensor chip 100B seen from above in the Z-axis direction. As shown in Fig. 29, the sensor chip 100B differs from the sensor chip 100 (see Fig. 6 and the like) in that the ends of two second detection beams of a T-shaped beam structure are connected to each other in the detection block B1. Unlike the sensor chip 100, the sensor chip 100B does not have the first detection beams 131e, 132e, 133e, and 134e and the second detection beams 131f, 132f, 133f, and 134f. The detection blocks B2 to B4 also have the same structure as the detection block B1.

[0122] FIG. 30 is a partial plan view of the sensor chip 100C viewed from above in the Z-axis direction. As shown in FIG. 30, the sensor chip 100C differs from the sensor chip 100 (see FIG. 6, etc.) in that the ends of the second detection beams of the four T-shaped beam structures are connected to each other in the detection block B1. Unlike the sensor chip 100, the sensor chip 100C further includes a T-shaped beam structure 131T4 including a first detection beam 131g and a second detection beam 131h. The T-shaped beam structure 131T4 is disposed to face the T-shaped beam structure 131T3 across the connection portion 141. The detection blocks B2 to B4 also have the same structure as the detection block B1.

[0123] In this way, the number of T-shaped beam structures in the sensor chip is not limited to three, and may be two as in the sensor chip 100B, or four as in the sensor chip 100C. In either case, each detection block has two or more sets of T-shaped beam structures, so that the first detection beam or the second detection beam constituting the T-shaped beam structure can be greatly deformed. Therefore, the Fx input and the Fy input can be effectively detected, and the detection beam will not be destroyed even if there is a large Fx input and / or Fy input. That is, in either sensor chip, the beam's destruction resistance against displacement in various directions can be improved. As a result, a sensor chip that can handle a large rating and can improve the measurement range and load resistance can be realized.

[0124] However, it is difficult to detect displacement in six axial directions when there are only two T-shaped beam structures. Also, having more T-shaped beam structures is advantageous in that it is easier to separate against multi-axial forces, but is disadvantageous in that the chip size tends to become larger. Considering these points, it can be said that it is preferable to have three T-shaped beam structures when detecting displacement in six axial directions.

[0125] Second Modification of the First Embodiment In the second modification of the first embodiment, an example of a strain generating body having a structure different from that of the first embodiment is shown. Note that in the second modification of the first embodiment, the description of the same components as those of the already described embodiment may be omitted.

[0126] FIG. 31 is a perspective view of the flexure body 200A. FIG. 32 is a cross-sectional perspective view of the flexure body 200A. Referring to FIGS. 31 and 32, the flexure body 200A has a force receiving plate 210, a strain generating part 220, an input transmission part 230A, and a cover plate 240A. The strain generating part 220 is laminated on the force receiving plate 210, the input transmission part 230A is laminated on the strain generating part 220, and the cover plate 240A is laminated on the input transmission part 230A, forming a substantially cylindrical flexure body 200A as a whole. The center part of the cover plate 240A can be opened and closed by an inner cover part 241. The force receiving plate 210 and the strain generating part 220 are the same as those of the flexure body 200.

[0127] Fig. 33 is a perspective view of the top side illustrating an input transmission section constituting the strain body. As shown in Fig. 33, the input transmission section 230A has a basic structure similar to that of the input transmission section 230. However, the input transmission section 230A is formed to be thinner than the input transmission section 230.

[0128] Fig. 34 is a perspective view illustrating a cover plate constituting the strain generating body. As shown in Fig. 34, the cover plate 240A is an approximately disk-shaped member overall, and is a member that protects internal components (such as the sensor chip 100). The cover plate 240A is formed to be thicker than, for example, the force receiving plate 210, the strain generating portion 220, and the input transmitting portion 230A, and has a wide internal space on the input transmitting portion 230A side. The cover plate 240A is provided with through holes 248 and 249. The through hole 249 is closed by the inner cover portion 241 (see Fig. 31).

[0129] In this way, the dividing positions of the components constituting the flexure body can be changed in consideration of the internal space to be provided in the flexure body, ease of assembly, etc. In the example shown in Figures 31 to 34, the dividing positions of the input transmission section and the cover plate are changed compared to Figure 1 etc., but in this case, it is possible to provide a larger internal space on the cover plate 240A side, so that more components can be incorporated.

[0130] <Modification 3 of the First Embodiment> In the third modification of the first embodiment, another example of a strain generating body having a structure different from that of the first embodiment is shown. Note that in the third modification of the first embodiment, the description of the same components as those of the already described embodiments may be omitted.

[0131] Fig. 35 is a side view of the flexure body 200B. Referring to Fig. 35, the flexure body 200B has a force receiving plate 210, a strain generating part 220B, an input transmission part 230, and a cover plate 240. The strain generating part 220B is laminated on the force receiving plate 210, the input transmission part 230 is laminated on the strain generating part 220B, and the cover plate 240 is laminated on the input transmission part 230, thereby forming the flexure body 200B having a substantially cylindrical shape as a whole. The force receiving plate 210, the input transmission part 230, and the cover plate 240 are the same as those of the flexure body 200.

[0132] FIG. 36 is a perspective view of the lower surface side illustrating the strain generating part constituting the strain body. That is, in FIG. 36, the strain generating part 220B is upside down compared to FIG. 35. As shown in FIG. 35 and FIG. 36, the strain generating part 220B has a protruding part 225 protruding toward the force receiving plate 210. The protruding part 225 is substantially circular in a plan view and is shaped so as to be able to come into contact with the central part 212 of the force receiving plate 210. The protruding amount of the protruding part 225 from the lower surface of the strain generating part 220B is, for example, about 0.5 mm. The protruding part 225 is joined to the central part 212 of the force receiving plate 210 by diffusion bonding, but may be joined by screw fastening or welding. The height of the protruding part 225 becomes a gap formed between the strain generating part 220B and the force receiving plate 210 after the strain generating part 220B and the force receiving plate 210 are joined.

[0133] In order for the force receiving plate 210 to receive a force and be displaced, a gap is required between the strain generating part 220B. In the strain generating body 200B, by providing a protrusion 225 on the strain generating part 220B, a gap can be easily provided between the force receiving plate 210 and the strain generating part 220B. That is, by providing the protrusion 225 on the strain generating part 220B and controlling the height of the protrusion 225, the gap between the strain generating part 220B and the force receiving plate 210 can be controlled. For example, by precisely controlling the height of the protrusion 225 by polishing or the like before bonding the strain generating part 220B and the force receiving plate 210, the gap after bonding can be controlled as desired. In addition, by providing the protrusion 225 on the strain generating part 220B, a narrow gap that is difficult to form by mechanical processing such as bonding or wire cutting can be formed. In addition, when the strain generating part 220B and the force receiving plate 210 are bonded by diffusion bonding, a bonding strength equivalent to the material strength can be obtained.

[0134] The protrusion may be provided on the force receiving plate 210 side, or may be provided on both the strain generating part 220B and the force receiving plate 210. In either case, the protrusion is provided between the strain generating part 220B and the force receiving plate 210, and functions as a gap defining part that defines the gap between the strain generating part 220B and the force receiving plate 210.

[0135] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims. [Explanation of symbols]

[0136] 1 Force sensor device, 100, 100A, 100B, 100C Sensor chip, 101 to 105 Support portion, 111 to 114 Frame portion, 121 to 124 Connection portion, 131a, 131c, 131e, 131g, 132a, 132c, 132e, 133a, 133c, 133e, 134a, 134c, 134e First detection beam, 131b, 131d, 131f, 131h, 132b, 132d, 132f, 133b, 133d, 133f, 134b, 134d, 134f 2nd detection beam, 131T1, 131T2, 131T3, 131T4, 132T1, 132T2, 132T3, 133T1, 133T2, 133T3, 134T1, 134T2, 134T3T-shaped beam structure, 141~144 Connection part, 151~154 Point of force, 200, 200A, 200B Strain body, 210 Force receiving plate, 211, 221, 231 Outer frame, 212, 222, 232 Center part, 213, 223, 233 Beam structure, 218, 228, 238, 248 Through hole, 220, 220B Strain part, 220x, 235x Groove, 224 First connection, 225 Protrusion, 230, 230A input transmission part, 234 inner frame part, 235 storage part, 235a vertical support part, 235b horizontal support part, 235c second connection part, 240, 240A cover plate, 241 inner cover part

Claims

1. a strain-generating part including a movable part that is deformed when subjected to a force or moment in a predetermined axial direction, and a non-movable part that is not deformed when subjected to the force or moment; an input transmission part that is joined to the non-movable part and does not deform when receiving the force or the moment, the input transmission unit includes a housing portion capable of housing a sensor chip that detects the force or the moment, the sensor chip that can be accommodated in the accommodation portion has a first portion and a second portion that change their relative positions when subjected to the force or the moment, the movable portion includes a first connection portion extending toward the input transmission portion and connected to one of the first portion and the second portion, the housing portion includes a second connection portion connected to the other of the first portion and the second portion, the first connection portion transmits deformation of the strain-flexing portion to the sensor chip in response to the force or moment, a positional relationship between the first portion and the second portion changes in response to the deformation, and the second connection portion does not deform in response to the force or moment, The input transmission unit is A second frame portion; a second central portion disposed inside the second frame portion and spaced apart from the second frame portion; a plurality of second beam structures bridging the second frame portion and the second central portion; The second central portion includes a third frame portion connected to the second beam structure, and the accommodation portion extending from the third frame portion toward the strain-flexing portion.

2. The strain-generating portion is A first frame portion; a first central portion disposed inside the first frame portion and spaced apart from the first frame portion; a plurality of first beam structures bridging the first frame portion and the first central portion; The flexure body according to claim 1 , wherein the first frame portion is included in the non-movable portion, and the first beam structure and the first central portion are included in the movable portion.

3. Each of the first beam structures is T-shaped and includes a first beam and a second beam extending from a central portion of the first beam in a direction perpendicular to the first beam, The flexure body according to claim 2 , wherein both ends of the first beam are connected to the first frame portion, and an end of the second beam is connected to the first central portion.

4. The flexure body according to claim 2 or 3, wherein, in a plan view, the first beam structures are disposed point-symmetrically with respect to a center of the flexure portion.

5. The flexure body according to claim 2 , comprising four first beam structures.

6. 6. The flexure body according to claim 1, wherein the accommodation portion has four vertical support portions extending vertically from the third frame portion toward the flexure portion, and four horizontal support portions extending horizontally from ends of the vertical support portions and intersecting at a center of the third frame portion.

7. The flexure body according to claim 6 , wherein, in a plan view, the third frame portion is ring-shaped, and the four horizontal support portions are cross-shaped.

8. The flexure body according to claim 1 , wherein the flexure portion and the input transmission portion are diffusion-bonded.

9. 9. The strain generating body according to claim 1, wherein a force receiving plate to which the force or the moment is input from an object to be measured is joined to an opposite side of the strain generating portion from the input transmitting portion.

10. The flexure body according to claim 9 , further comprising a gap defining portion provided between the strain generating portion and the force receiving plate for defining a gap between the strain generating portion and the force receiving plate.

11. The flexure body according to claim 1 , further comprising a cover plate for protecting internal components, the cover plate being joined to a side of the input transmission portion opposite to the flexure portion.

12. A force sensor device comprising: the strain element according to claim 1; and the sensor chip.

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