Displacement detection device and torque sensor

Abstract

A displacement detecting device (10) and a torque sensor (50) are provided with: a movable portion (16) connected to a first member and a second member and changing a gap (G) as the second member (14) is displaced in a prescribed direction relative to the first member (12); and a detection portion (detection circuit (20)) detecting the displacement of the second member (14) in the prescribed direction relative to the first member (12) based on the change in the gap (G), the movable portion making the amount of change in the gap (G) greater than the amount of displacement of the second member in the prescribed direction relative to the first member.

Description

TECHNICAL FIELD

[0001] The present application relates to a displacement detecting device that detects displacement of a second member in a prescribed direction with respect to a first member, and a torque sensor provided with the displacement detecting device. BACKGROUND

[0002] A torque sensor that detects torque is provided in a movable shaft portion of a collaborative robot. By providing the torque sensor, the collaborative robot has a contact stop function. In addition, by providing the torque sensor, the collaborative robot is able to perform operation of the robot based on direct teaching (also referred to as lead-through). As a type of torque sensor, there are a strain gauge type that is provided with a strain gauge and an electrostatic capacitance type that is provided with a displacement detecting device. In Japanese Patent Application Publication No. 2019-174477, a torque sensor of the electrostatic capacitance type is shown. SUMMARY

[0003] In a method of increasing the sensitivity of a torque sensor of the electrostatic capacitance type, there are a method of making the gap of the opposing electrodes narrower and a method of increasing the area of the opposing electrodes. However, the gap of the opposing electrodes has a lower limit value. On the other hand, if the area of the opposing electrodes is increased, there is a problem in that the size of the entire sensor becomes large.

[0004] Therefore, an object of the present application is to provide a displacement detecting device and a torque sensor that are able to increase sensitivity without increasing the size of the members used.

[0005] A first aspect of the present application is a displacement detecting device that detects displacement of a second member in a prescribed direction with respect to a first member, the displacement detecting device including: a movable portion that is connected to the first member and the second member and that changes a gap as the second member is displaced in the prescribed direction with respect to the first member; and a detection portion that detects displacement of the second member in the prescribed direction with respect to the first member based on a change in the gap, the movable portion being configured so that the amount of change in the gap is greater than the amount of displacement of the second member in the prescribed direction with respect to the first member.

[0006] A second aspect of the present application is a torque sensor provided with the displacement detecting device of the first aspect, the torque sensor including: an inner ring and an outer ring; and an elastically deformable body that is connected to the inner ring and the outer ring, the outer ring having a rigidity in a direction in which the outer ring rotates with respect to the inner ring, that is, a torque direction, that is smaller than the rigidity in other directions, the inner ring being the first member, and the outer ring being the second member.

[0007] According to the present application, it is possible to increase sensitivity without increasing the size of the members used. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1is a view showing the configuration of the displacement detecting device of the first embodiment.

[0009] Figure 2 is a view showing the configuration of the displacement detecting device of the first embodiment.

[0010] Figure 3 is a view showing the configuration of the displacement detecting device of the second embodiment.

[0011] Figure 4 is a view showing the configuration of the displacement detecting device of the third embodiment.

[0012] Figure 5 is a view showing the configuration of the displacement detecting device of the third embodiment.

[0013] Figure 6 is a view showing the configuration of the torque sensor of the fourth embodiment.

[0014] Figure 7 is a view showing the configuration of the modification of the fourth embodiment. DETAILED DESCRIPTION

[0015] The preferred embodiments of the displacement detecting device and the torque sensor of the present application will be explained in detail below with reference to the drawings.

[0016] [1 First Embodiment]

[0017] In the following explanation, three directions, X direction, Y direction, and Z direction, are used. The X direction and the Y direction are orthogonal to each other. In addition, the Z direction is orthogonal to the X direction and the Y direction.

[0018] [1-1 Configuration of Displacement Detecting Device 10]

[0019] The displacement detecting device 10 of the first embodiment will be explained using the drawings. Figure 1 and Figure 2 is a view showing the configuration of the displacement detecting device 10 of the first embodiment. Figure 1 The displacement detecting device 10 is shown in a state where no external force is acting on the second member 14. Figure 2 The displacement detecting device 10 is shown in a state where an external force is acting to displace the second member 14 in a prescribed direction. Here, the right direction of the paper is set as the +X direction, the left direction of the paper is set as the -X direction, the up direction of the paper is set as the +Y direction, the down direction of the paper is set as the -Y direction, the front direction of the paper is set as the +Z direction, and the back direction of the paper is set as the -Z direction. Figure 1

[0020] ​The displacement detecting device 10 is attached to an object (not shown). The displacement detecting device 10 detects a deformation of a prescribed direction (X direction) of the object. In addition, the displacement detecting device 10 detects an external force acting on the prescribed direction of the object. The displacement detecting device 10 has a first member 12, a second member 14, a movable portion 16, a counter electrode 18, and a detection circuit (detection portion) 20.

[0021] The first member 12 and the second member 14 are attached to the object. In addition to this, the first member 12 and the second member 14 can be formed integrally with the object. The second member 14 is disposed in the +X direction as viewed from the first member 12. The movable portion 16 is provided between the first member 12 and the second member 14. The movable portion 16 has a movable body 22 disposed on the +Y direction side and a movable body 22 disposed on the -Y direction side.

[0022] Each movable body 22 has two bent portions 24, a holding portion 26, a first inclined portion 28, and a second inclined portion 30. The movable body 22 is an elastic member (for example, a plate spring). The movable body 22 is elastically deformed by the two bent portions 24 to stretch and contract in the X direction. Each bent portion 24 is parallel to the Z direction. The holding portion 26 is interposed between the two bent portions 24. The holding portion 26 is parallel to the X direction and the Z direction. The holding portion 26 of one movable body 22 and the holding portion 26 of the other movable body 22 hold the counter electrode 18. The first inclined portion 28 is interposed between the bent portion 24 on the -X direction side and the first member 12. The first inclined portion 28 is inclined with respect to the X direction. The second inclined portion 30 is interposed between the bent portion 24 on the +X direction side and the second member 14. The second inclined portion 30 is inclined with respect to the X direction. The first inclined portion 28 of the movable body 22 on the +Y direction side is inclined in such a manner that the farther the position from the bent portion 24, the more the position is on the +Y direction side. Similarly, the second inclined portion 30 of the movable body 22 on the +Y direction side is inclined in such a manner that the farther the position from the bent portion 24, the more the position is on the +Y direction side. On the other hand, the first inclined portion 28 of the movable body 22 on the -Y direction side is inclined in such a manner that the farther the position from the bent portion 24, the more the position is on the -Y direction side. Similarly, the second inclined portion 30 of the movable body 22 on the -Y direction side is inclined in such a manner that the farther the position from the bent portion 24, the more the position is on the -Y direction side. The initial value of the inclination angle θ of the first inclined portion 28 with respect to the X direction and the initial value of the inclination angle θ of the second inclined portion 30 with respect to the X direction are the same. The initial value of the inclination angle θ is less than 45 degrees. The initial value of the inclination angle θ refers to the angle when the external force in the X direction is not acting on the object.

[0023] The opposing electrode 18 has a set of electrodes facing each other. The set of electrodes includes a first electrode 18a and a second electrode 18b. The first electrode 18a is mounted on the holding portion 26 of the movable body 22 located in the +Y direction. The first electrode 18a faces the -Y direction. The second electrode 18b is mounted on the holding portion 26 of the movable body 22 located in the -Y direction. The second electrode 18b faces the +Y direction. A gap G, capable of extending and retracting in the Y direction, is formed between the first electrode 18a and the second electrode 18b.

[0024] The detection circuit 20 is a circuit that applies a predetermined voltage to the opposing electrode 18 to detect the electrostatic capacitance value of the opposing electrode 18. The detection value of the detection circuit 20 is output to a computing device such as a computer (not shown). The computing device stores tables or formulas in advance. The tables or formulas correlate the change in the electrostatic capacitance value with the displacement of the second member 14 relative to the first member 12 in a predetermined direction (X direction). In addition, the tables or formulas correlate the change in the electrostatic capacitance value with an external force acting in the predetermined direction (X direction).

[0025] [Operation of displacement detection device 10 (1-2)]

[0026] When an external force causing deformation of the object in the X direction is applied, the displacement detection device 10 detects the displacement from... Figure 1 The state transition shown Figure 2 The state is shown. The second member 14 displaces in the +X direction (arrow A1 direction). As the second member 14 displaces in the +X direction, the two bent portions 24 of each movable body 22 elastically deform. The tilt angles θ of the first tilting portion 28 and the second tilting portion 30 become smaller than their initial values. If the tilt angle θ decreases, the holding portion 26 of the movable body 22 in the +Y direction displaces in the +Y direction (arrow A2 direction). Similarly, if the tilt angle θ decreases, the holding portion 26 of the movable body 22 in the -Y direction displaces in the -Y direction (arrow A3 direction). As a result, the first electrode 18a and the second electrode 18b displace, and the gap G between the relative electrodes 18 increases.

[0027] The arithmetic unit (not shown) calculates the displacement of the second component 14 relative to the first component 12 and the external force acting in the direction of the displacement based on the electrostatic capacitance value detected by the detection circuit 20 and pre-stored tables.

[0028] [1-3 Effects of the displacement detection device 10]

[0029] In the first embodiment, the movable part 16 transforms the displacement of the second member 14 relative to the first member 12 into an action that changes the gap G of the opposing electrode 18. The direction of the gap G change intersects the direction of the displacement of the second member 14. As an example, in Figure 1 and Figure 2In the displacement detection device 10 shown, the direction in which the gap G changes (Y direction) and the direction in which the second member 14 is displaced (X direction) are orthogonal to each other. In addition, the movable portion 16 amplifies the displacement amount of the second member 14 and transmits it to the counter electrode 18.

[0030] According to the first embodiment, the initial value of the inclination angle θ of the first inclined portion 28 and the initial value of the inclination angle θ of the second inclined portion 30 are less than 45 degrees. Therefore, the amount of change in the gap G of the counter electrode 18 becomes larger than the displacement amount of the second member 14. In addition, according to the first embodiment, both the first electrode 18a and the second electrode 18b are displaced by the two movable bodies 22. Therefore, the amount of change in the gap G is further increased. The amount of change in the gap G being larger than the displacement amount of the second member 14 means that the sensitivity of displacement detection is increased. That is, according to the first embodiment, it is possible to increase the sensitivity of displacement detection without increasing the size of the member (counter electrode 18) used.

[0031] Further, the first embodiment is less likely to be affected by an external force acting in a direction other than the X direction because it uses the movable body 22 like a plate spring. That is, in the first embodiment, the influence of other-axis interference is small. Therefore, it is possible to reduce interference and perform high-precision displacement detection.

[0032] [1-4 Modification of the First Embodiment]

[0033] The displacement detection device 10 can be provided with an optical or magnetic distance sensor instead of the counter electrode 18.

[0034] In addition, the movable portion 16 can have only one movable body 22. In this case, for example, the first electrode 18a is mounted on the movable body 22. The second electrode 18b is fixed at a position opposite the first electrode 18a.

[0035] [2 Second Embodiment]

[0036] A displacement detection device 10 according to the second embodiment will be described with reference to the drawings. Figure 3 is a view showing the configuration of the displacement detection device 10 according to the second embodiment. Figure 3 The displacement detection device 10 is shown in a state in which no external force is acting on the second member 14. In the second embodiment, the same reference numerals are assigned to the same configuration elements as those of the first embodiment, and detailed description thereof will be omitted.

[0037] In the first embodiment, each movable body 22 is an elastic member having two bent portions 24. Alternatively, each movable body 22 can be an elastic member having two curved portions 32 as in the second embodiment. The second embodiment has the same effects as the first embodiment. In the second embodiment, the two curved portions 32 are elastically deformed.

[0038] As with the first embodiment, the displacement detection device 10 of the second embodiment can also have an optical or magnetic distance sensor in place of the opposing electrodes 18. In addition, the movable section 16 can also have only one movable body 22.

[0039] [3 Third Embodiment]

[0040] [3-1 Configuration of Displacement Detection Device 10]

[0041] The displacement detection device 10 of the third embodiment will be described using the drawings. Figure 4 and Figure 5 is a view showing the configuration of the displacement detection device 10 of the third embodiment. Figure 4 The displacement detection device 10 is shown in a state in which no external force is acting on the second member 14. Figure 5 The displacement detection device 10 is shown in a state in which an external force is acting to displace the second member 14 in a prescribed direction. In the third embodiment, the same reference numerals are assigned to the same configuration elements as in the first embodiment, and detailed description thereof will be omitted. As with the first embodiment, the right direction on the paper is taken as the +X direction, the left direction on the paper is taken as the -X direction, the upper direction on the paper is taken as the +Y direction, the lower direction on the paper is taken as the -Y direction, the front direction on the paper is taken as the +Z direction, and the back direction on the paper is taken as the -Z direction.

[0042] The movable section 16 of the third embodiment is composed of two movable bodies 42a, 42b. One movable body 42a has a holding section 44a and a rod section 46a. The other movable body 42b has a holding section 44b and a rod section 46b.

[0043] Viewed from the holding part 44b of the other movable body 42b, the holding part 44a of one movable body 42a is positioned in the +X direction. Holding parts 44a and 44b hold the opposing electrode 18. Rod parts 46a and 46b intersect at a midpoint 48. Rod parts 46a and 46b are rotating members capable of rotating about an axis extending in the Z direction through the midpoint 48. Rod parts 46a and 46b are connected to each other at the midpoint 48. A first member 12 is oscillatingly connected to one end of rod part 46a. A holding part 44a is oscillatingly connected to the other end of rod part 46a. A midpoint 48 is provided between one end of rod part 46a and the other end of rod part 46a. A second member 14 is oscillatingly connected to one end of rod part 46b. A holding part 44b is oscillatingly connected to the other end of rod part 46b. An intermediate point 48 is provided between one end of the rod 46b and the other end of the rod 46b. In the rod 46a, the distance Da1 from the intermediate point 48 to the retaining part 44a is longer than the distance Da2 from the intermediate point 48 to the first member 12. In the rod 46b, the distance Db1 from the intermediate point 48 to the retaining part 44b is longer than the distance Db2 from the intermediate point 48 to the second member 14. Furthermore, distances Da1 and Db1 are the same. Distances Da2 and Db2 are the same.

[0044] The first electrode 18a of the opposing electrode 18 is mounted on the holding portion 44a located in the +X direction and facing the -X direction. The second electrode 18b of the opposing electrode 18 is mounted on the holding portion 44b located in the -X direction and facing the +X direction. A gap G that can expand and contract in the X direction is formed between the first electrode 18a and the second electrode 18b.

[0045] [3-2 Operation of displacement detection device 10]

[0046] When an external force causing deformation of the object in the X direction is applied to the displacement detection device 10, the displacement detection device 10... Figure 4 The state transition shown Figure 5 The state is shown. The second component 14 displaces in the +X direction (arrow A1 direction). As the second component 14 displaces in the +X direction, the two retaining parts 44a and 44b displace. Specifically, according to the lever principle, retaining part 44a displaces in the +X direction (arrow A4 direction), and retaining part 44b displaces in the -X direction (arrow A5 direction). The lever principle uses the midpoint 48 as the fulcrum, the first component 12 and the second component 14 as the force points, and the retaining parts 44a and 44b as the points of action. As a result, the first electrode 18a and the second electrode 18b displace, and the gap G between the relative electrodes 18 increases.

[0047] The operation device (not shown) operates the displacement amount of the second member 14 with respect to the first member 12 and the external force acting in the displacement direction based on the electrostatic capacitance value detected by the detection circuit 20 and a table or the like stored in advance.

[0048] [3-3 Effects of the displacement detection device 10]

[0049] In the third embodiment, the movable portion 16 converts the operation of displacing the second member 14 with respect to the first member 12 into the operation of changing the gap G of the counter electrode 18. The direction (X direction) in which the gap G changes coincides with the direction (X direction) in which the second member 14 is displaced. In addition, the movable portion 16 amplifies the displacement amount of the second member 14 and transmits it to the counter electrode 18.

[0050] According to the third embodiment, the distance Da1 is longer than the distance Da2, and the distance Db1 is longer than the distance Db2. Therefore, the amount of change in the gap G of the counter electrode 18 is larger than the displacement amount of the second member 14. In addition, according to the third embodiment, both the first electrode 18a and the second electrode 18b are displaced by the two movable bodies 42a, 42b. Therefore, the amount of change in the gap G is further increased. The amount of change in the gap G being larger than the displacement amount of the second member 14 means that the sensitivity of displacement detection is increased. That is, according to the third embodiment, it is possible to increase the sensitivity of displacement detection without increasing the size of the member (counter electrode 18) used.

[0051] Further, according to the third embodiment, no member (elastic member or the like) that generates fatigue failure is used. Therefore, it is possible to prolong the life of the movable portion 16.

[0052] [3-4 Modification of the third embodiment]

[0053] The movable bodies 42a, 42b can also have displacement rotary joints with sliders at the intermediate points 48.

[0054] As with the first and second embodiments, the displacement detection device 10 of the third embodiment can also have an optical or magnetic distance sensor instead of the counter electrode 18.

[0055] [4 Fourth embodiment]

[0056] [4-1 Configuration of the torque sensor 50]

[0057] The torque sensor 50 of the fourth embodiment will be described with reference to the drawings. Figure 6 is a view that shows the configuration of the torque sensor 50 of the fourth embodiment. In the fourth embodiment, the same symbols are assigned to the same configuration elements as those of the first to third embodiments, and detailed description thereof will be omitted.

[0058] The torque sensor 50 has an inner ring 52, an outer ring 54, a plurality of elastic deformers 56, and the displacement detection device 10 of any one of the first to third embodiments. The inner ring 52, the outer ring 54, and the elastic deformers 56 are, for example, metal. The inner ring 52, the outer ring 54, and the elastic deformers 56 are integrally formed.

[0059] The inner ring 52 is a cylinder. The outer ring 54 is a cylinder. The outer ring 54 houses the inner ring 52 on the inner side. The axis of the inner ring 52 is the same as the axis of the outer ring 54. The inner ring 52 rotates with respect to the outer ring 54. In addition, the outer ring 54 rotates with respect to the inner ring 52. Thereby, the inner ring 52 and the outer ring 54 can relatively displace. A first mounting portion 58 protruding toward the outer ring 54 is formed on the outer peripheral surface of the inner ring 52. A second mounting portion 60 protruding toward the inner ring 52 is formed on the inner peripheral surface of the outer ring 54.

[0060] The elastic deformers 56 are beams formed between the inner ring 52 and the outer ring 54. The elastic deformers 56 are formed in the radial direction of the outer ring 54. One end of the elastic deformers 56 is connected to the outer peripheral surface of the inner ring 52. The other end of the elastic deformers 56 is connected to the inner peripheral surface of the outer ring 54. In the rigidity of the elastic deformers 56, the rigidity in the axial direction and the radial direction of the inner ring 52 and the outer ring 54 is high. In the rigidity of the elastic deformers 56, the rigidity in the circumferential direction of the inner ring 52 and the outer ring 54 is low. Therefore, the elastic deformers 56 are difficult to deform in the axial direction and the radial direction. In addition, the elastic deformers 56 elastically deform with rotation of the inner ring 52 or the outer ring 54.

[0061] The displacement detection device 10 is connected to the inner ring 52 and the outer ring 54. The first member 12 of the displacement detection device 10 is connected to the first mounting portion 58. Alternatively, the first member 12 itself can be the first mounting portion 58. The second member 14 of the displacement detection device 10 is connected to the second mounting portion 60. Alternatively, the second member 14 itself can be the second mounting portion 60. The posture of the displacement detection device 10 is not limited. For example, the direction in which the gap G of the opposing electrodes 18 changes can coincide with the axial direction of the inner ring 52 and the axial direction of the outer ring 54. Figures 1 to 5 ) can coincide with the axial direction of the inner ring 52 and the axial direction of the outer ring 54.

[0062] The operation device (not shown) stores a table or an operation formula in advance. The table or the operation formula associates the amount of variation in the electrostatic capacitance value of the displacement detection device 10 with the amount of displacement of the outer ring 54 in the circumferential direction with respect to the inner ring 52. In addition, the table or the operation formula associates the amount of variation in the electrostatic capacitance value of the displacement detection device 10 with the torque acting in the circumferential direction.

[0063] [4-2 Action of the Torque Sensor 50]

[0064] In a case where the inner wheel 52 is fixed and a torque in a predetermined direction (arrow A6 direction) acts on the outer wheel 54, the outer wheel 54 rotates around the inner wheel 52. According to this rotation, the second member 14 of the displacement detecting device 10 is displaced with respect to the first member 12. Then, as explained in [1-2] and [3-2] above, the gap G of the opposing electrodes 18 becomes large.

[0065] The operation device (not shown) operates the displacement amount of the second member 14 with respect to the first member 12 and the torque acting on the outer wheel 54, based on the electrostatic capacity value detected by the detection circuit 20 and a table or the like stored in advance.

[0066] On the other hand, in a case where the outer wheel 54 is fixed and a torque in a predetermined direction (arrow A7 direction) acts on the inner wheel 52, the operation device (not shown) also operates the displacement amount of the second member 14 with respect to the first member 12 and the torque acting on the inner wheel 52.

[0067] [4-3 Effects of Torque Sensor 50]

[0068] In the fourth embodiment, the torque sensor 50 has the displacement detecting device 10 of any one of the first to third embodiments. Therefore, according to the fourth embodiment, the same effects as the first to third embodiments can be obtained. In addition, the elastic deformation body 56 connecting the inner wheel 52 and the outer wheel 54 has low rigidity in the circumferential direction of the inner wheel 52 and the outer wheel 54. Therefore, the torque sensor 50 can detect a torque with good sensitivity.

[0069] In addition, according to the fourth embodiment, the displacement detecting device 10 is provided separately from the inner wheel 52, the outer wheel 54, and the elastic deformation body 56. Therefore, the displacement detecting device 10 can be designed freely regardless of the structure of the inner wheel 52, the outer wheel 54, and the elastic deformation body 56. Therefore, the displacement detecting device 10 can be manufactured at a low cost.

[0070] [4-4 Modification of Fourth Embodiment]

[0071] The torque sensor 50 can have a plurality of displacement detecting devices 10. In this case, the plurality of displacement detecting devices 10 can be arranged in the circumferential direction of the inner wheel 52 (and the outer wheel 54). Alternatively, the plurality of displacement detecting devices 10 can be arranged in the axial direction of the inner wheel 52 (and the outer wheel 54). In Figure 7 In the torque sensor 50 shown in the drawing, four displacement detecting devices 10 are arranged at 90-degree intervals in the circumferential direction. In a case where the plurality of displacement detecting devices 10 are arranged in the axial direction of the inner wheel 52 (and the outer wheel 54), the plurality of displacement detecting devices 10 can be connected to the same first mounting portion 58 and the same second mounting portion 60.

[0072] According to a modification example using a plurality of displacement detecting devices 10, the influence of interference can be reduced, for example, by averaging the detection values. Thus, the correct torque can be calculated. In addition, according to the modification example, by preparing a plurality of equivalent torque detecting systems, multiple checks of failure can be performed.

[0073] [5Invention according to the embodiments]

[0074] The following description of the invention that can be grasped according to the above embodiments and modification examples.

[0075] A first aspect of the invention is a displacement detecting device (10) that detects displacement of a second member (14) in a prescribed direction with respect to a first member (12), the displacement detecting device including: a movable portion (16) that is connected to the first member and the second member and changes a gap (G) as the second member is displaced in the prescribed direction with respect to the first member; and a detection portion (20) that detects displacement of the second member in the prescribed direction with respect to the first member based on a change in the gap, the movable portion being configured so that the amount of change in the gap is greater than the amount of displacement of the second member in the prescribed direction with respect to the first member.

[0076] In the first aspect of the invention, two movable bodies (22, 42a, 42b) can be included in the movable portion, and a set of opposing electrodes (18) can be provided, the set of opposing electrodes being composed of a first electrode (18a) and a second electrode (18b), the first electrode (18a) being mounted on one of the movable bodies, the second electrode (18b) being mounted on the other of the movable bodies and opposing the first electrode, the set of opposing electrodes forming the gap between the first electrode and the second electrode, the detection portion detecting displacement of the second member in the prescribed direction with respect to the first member based on a change in the electrostatic capacitance value of the opposing electrodes accompanying a change in the gap.

[0077] In the first aspect of the invention, each of the movable bodies (22) can be an elastic member having a bent portion (24) or a curved portion (32) that elastically deforms, whereby the gap changes.

[0078] In the first aspect of the present application, each of the movable bodies can have a holding portion (26) interposed between the two bending portions, parallel to the prescribed direction, holding the first electrode or the second electrode; a first inclined portion (28) interposed between the bending portion on one side and the first member, inclined with respect to the prescribed direction; and a second inclined portion (30) interposed between the bending portion on the other side and the second member, inclined with respect to the prescribed direction, and as the second member is displaced with respect to the prescribed direction of the first member, the bending portions elastically deform, the angle of inclination (θ) of the first inclined portion with respect to the prescribed direction and the angle of inclination (θ) of the second inclined portion with respect to the prescribed direction change, and thereby the gap changes.

[0079] In the first aspect of the present application, the angle of inclination of the first inclined portion with respect to the prescribed direction and the angle of inclination of the second inclined portion with respect to the prescribed direction can be less than 45 degrees.

[0080] In the first aspect of the present application, the direction in which the gap changes can also cross the prescribed direction.

[0081] In the first aspect of the present application, the two movable bodies (42a, 42b) intersect each other at a middle point (48) and are rotatably connected at the middle point by two rotating members, the first member is connected to one end portion of the movable body (42a) on one side and the first electrode is attached to the other end portion, the distance (Da1) from the middle point to the first electrode is longer than the distance (Da2) from the middle point to the first member, the second member is connected to one end portion of the movable body (42b) on the other side and the second electrode is attached to the other end portion, the distance (Db1) from the middle point to the second electrode is longer than the distance (Db2) from the middle point to the second member, and according to the principle of a lever with the middle point as the fulcrum, the first member and the second member as the points of force, and the first electrode and the second electrode as the points of action, the gap changes.

[0082] In the first aspect of the present application, the direction in which the gap changes can also coincide with the prescribed direction.

[0083] The second aspect of the present application is a torque sensor (50) provided with the displacement detection device of the first aspect, the torque sensor being provided with an inner wheel (52) and an outer wheel (54), and an elastically deformable body (56) connected to the inner wheel and the outer wheel, the rigidity of the outer wheel with respect to the direction of rotation, i.e., the torque direction, being smaller than the rigidity with respect to other directions, the inner wheel being the first member, and the outer wheel being the second member.

[0084] In the second aspect of the application, the direction of the gap variation can coincide with the axial direction of the inner wheel and the outer wheel.

[0085] In the second aspect of the application, the displacement detection device can be provided separately from the inner wheel, the outer wheel, and the elastically deformable body.

[0086] In addition, the displacement detection device and the torque sensor of the application are not limited to the above-described embodiments and modifications, and various configurations can of course be adopted without departing from the gist of the application.

Claims

1. A displacement detecting device that detects displacement of a second member (14) in a prescribed direction with respect to a first member (12), the displacement detecting device (10) characterized by comprising: a movable portion (16) that is connected to the first member and the second member and changes a gap as the second member is displaced in the prescribed direction with respect to the first member; and a detection portion (20) that detects displacement of the second member in the prescribed direction with respect to the first member based on a change in the gap, wherein the movable portion causes the amount of change in the gap to be greater than the amount of displacement of the second member in the prescribed direction with respect to the first member, and causes the gap to increase as the first member and the second member move apart from each other, each of the movable portions includes a leaf spring having a bent portion (24) or a curved portion (32), and the bent portion or the curved portion elastically deforms, whereby the gap changes.

2. The displacement detecting device according to claim 1, further comprising: two movable bodies (22, 42a, 42b) included in the movable portions; and a set of opposing electrodes (18) composed of a first electrode (18a) mounted on one of the movable bodies and a second electrode (18b) mounted on the other of the movable bodies so as to oppose the first electrode and form the gap between the first electrode and the second electrode, wherein the detection portion is a detection circuit that detects displacement of the second member in the prescribed direction with respect to the first member based on a change in the electrostatic capacitance value of the opposing electrodes accompanying the change in the gap.

3. The displacement detecting device according to claim 2, wherein each of the movable bodies has: a holding portion (26) that is interposed between the two bent portions, is parallel to the prescribed direction, and holds the first electrode or the second electrode; a first inclined portion (28) that is interposed between the bent portion on one side and the first member and is inclined with respect to the prescribed direction; and a second inclined portion (30) that is interposed between the bent portion on the other side and the second member and is inclined with respect to the prescribed direction, and wherein the bent portions elastically deform, the inclination angle of the first inclined portion with respect to the prescribed direction and the inclination angle of the second inclined portion with respect to the prescribed direction change, and the gap changes as the second member is displaced in the prescribed direction with respect to the first member.

4. The displacement detecting device according to claim 3, wherein the inclination angle of the first inclined portion with respect to the prescribed direction and the inclination angle of the second inclined portion with respect to the prescribed direction are less than 45 degrees.

5. The displacement detecting device according to claim 1, wherein the direction in which the gap changes crosses the prescribed direction.

6. A displacement detecting device that detects displacement of a second member (14) in a prescribed direction with respect to a first member (12), ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The displacement detection device (10) is characterized by comprising: a movable portion (16) connected to the first member and the second member and changing a gap in accordance with displacement of the second member in the prescribed direction with respect to the first member; and a detection portion (20) detecting displacement of the second member in the prescribed direction with respect to the first member based on the change in the gap, the movable portion makes the amount of change in the gap larger than the amount of displacement of the second member in the prescribed direction with respect to the first member, and makes the gap increase as the first member and the second member move apart from each other, further comprising two movable bodies (22, 42a, 42b) included in the movable portion, and a pair of opposing electrodes (18) composed of a first electrode (18a) mounted on one of the movable bodies and a second electrode (18b) mounted on the other of the movable bodies opposite the first electrode, the pair of opposing electrodes (18) forming the gap between the first electrode and the second electrode, the detection portion is a detection circuit that detects displacement of the second member in the prescribed direction with respect to the first member based on a change in the electrostatic capacitance value of the pair of opposing electrodes in accordance with the change in the gap, the two movable bodies (42a, 42b) are two rotating members that intersect each other at a middle point (48) and are rotatably connected at the middle point, one end portion of the one of the movable bodies (42a) is connected to the first member, and the first electrode is mounted on the other end portion, the distance from the middle point to the first electrode is longer than the distance from the middle point to the first member, one end portion of the other of the movable bodies (42b) is connected to the second member, and the second electrode is mounted on the other end portion, the distance from the middle point to the second electrode is longer than the distance from the middle point to the second member, the gap changes in accordance with the lever principle with the middle point as a fulcrum, the first member and the second member as force points, and the first electrode and the second electrode as action points.

7. The displacement detection device according to claim 6, wherein the direction in which the gap changes coincides with the prescribed direction.

8. A torque sensor provided with the displacement detection device according to any one of claims 1 to 7, the torque sensor (50) being characterized by comprising: an inner ring (52) and an outer ring (54); an elastically deformable body connected to the inner ring and the outer ring, the elastically deformable body being less rigid in the direction in which the outer ring rotates with respect to the inner ring, i.e., the torque direction, than in other directions, the inner ring is the first member, the outer ring is the second member.

9. The torque sensor according to claim 8, wherein the direction in which the gap changes coincides with the axial direction of the inner ring and the outer ring.

10. The torque sensor according to claim 8, wherein The displacement detection device is arranged separately from the inner wheel, the outer wheel, and the elastically deformable body. The displacement detection device is arranged separately from the inner wheel, the outer wheel, and the elastically deformable body.

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