Manufacturing methods for sensors, devices, systems, and articles

Abstract

To provide a technique advantageous in improving detection accuracy of a sensor.SOLUTION: A sensor 10 comprises: a structure 5 that has at least four elastic parts 31-34 that are discretely arranged in a virtual plane; and detection means 8 that detects deformation of the structure 5. The structure 5 includes a metal component 51 that has at least the elastic part 31 and the elastic part 32 of the four elastic parts 31-34, a reinforcement component 56 that is joined to the metal component 51, and a reinforcement component 57 that is joined to the metal component 51. The reinforcement component 56 is arranged on one side with respect to the plane P, and the reinforcement component 57 is arranged on the other side with respect to the plane P.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a sensor. [Background technology]

[0002] Sensors that measure mechanical quantities applied to a structure are known, comprising a structure and a detection means for detecting the deformation of the structure. Patent Document 1 discloses a torque sensor comprising a fixing member, a connecting member, an intermediate member, and a detection unit. In this intermediate member, the rigidity in the radial direction of the torque sensor is smaller than the rigidity in the rotational direction of the torque sensor. This is said to reduce the influence of deformation of the torque sensor by the wave generator on the detected torque. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-174472 [Overview of the project] [Problems that the invention aims to solve]

[0004] Patent Document 1 examines rigidity in the radial and circumferential directions, but rigidity in other directions has not been sufficiently examined. Therefore, the present invention aims to provide a technology that is advantageous in improving the detection accuracy of sensors. [Means for solving the problem]

[0005] The means to solve the above problem are: A structure having at least four elastic parts discretely arranged in a virtual plane, A sensor comprising detection means for detecting deformation of the aforementioned structure, The aforementioned structure is Metal parts formed by bending sheet metal, A first reinforcing part connected to the aforementioned metal part, including a second reinforcing component coupled to the metal component The metal part has one surface parallel to the virtual plane and the other surface parallel to the virtual plane. where the first reinforcing component is Bonded to the aforementioned one side surface. formed, and the second reinforcing component is Bonded to the other side surface. formed characterized in that

Effect of the Invention

[0006] According to the present invention, it is possible to provide an advantageous technique for improving the detection accuracy of the sensor.

Brief Description of the Drawings

[0007] [Figure 1] Schematic diagram for explaining the sensor. [Figure 2] Schematic diagram for explaining the sensor. [Figure 3] Schematic diagram for explaining the sensor. [Figure 4] Schematic diagram for explaining the sensor. [Figure 5] Schematic diagram for explaining the sensor. [Figure 6] Schematic diagram for explaining the sensor. [Figure 7] Schematic diagram for explaining the sensor. [Figure 8] Schematic diagram for explaining the sensor. [Figure 9] Schematic diagram for explaining the sensor. [Figure 10] Schematic diagram for explaining the sensor. <( [Figure 11] Schematic diagram for explaining the sensor. [Figure 12] Schematic diagram for explaining the sensor. [Figure 13] Schematic diagram for explaining the sensor. [Figure 14] Schematic diagram for explaining the sensor. [Figure 15] Schematic diagram for explaining the manufacturing method of the sensor. [Figure 16] Schematic diagram for explaining the manufacturing method of the sensor. [Figure 17] Schematic diagram for explaining the manufacturing method of the sensor. [Figure 18]A schematic diagram illustrating the manufacturing method of the sensor. [Figure 19] A schematic diagram illustrating the sensor. [Figure 20] A schematic diagram illustrating the sensor. [Figure 21] A schematic diagram illustrating the manufacturing method of the sensor. [Figure 22] A schematic diagram illustrating the sensor. [Figure 23] A schematic diagram illustrating the sensor. [Figure 24] A schematic diagram illustrating the sensor. [Figure 25] A schematic diagram illustrating the equipment. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the following description and drawings, common components are denoted by the same reference numerals across multiple drawings. Therefore, common components will be described by referring to multiple drawings together, and descriptions of components denoted by the same reference numerals will be omitted as appropriate.

[0009] For different items with the same name, they can be distinguished by adding "item number ○" (where ○ is a number), such as "item number 1," "item number 2," etc. In the following explanation, when the signs N, N+1, N+2, ..., n-1, n (nN≧2) are consecutive natural numbers from N to n, the signs N, N+1, N+2, ..., n-1, n may be abbreviated as signs N~n. Also, when the total number of elements is K, the number of elements can be expressed as "at least k" using a number k less than or equal to K (k≦K). In this case, k elements are selected from the K elements in any combination. Furthermore, in mathematical formulas, [A&B] means at least one of A and B, and [C~D] means at least one of C~D.

[0010] Figure 1(a) schematically shows a sensor 10 according to this embodiment. The sensor 10 comprises a structure 5 and a detection means 8 for detecting deformation of the structure 5. Figure 1(a) shows a virtual plane P that is parallel to the xy plane in the xyz Cartesian coordinate system and parallel to the rθ plane in the rθz cylindrical coordinate system. The cylindrical coordinate system is represented by the r direction, θ direction and z direction. The r direction can be called the radial direction, the θ direction the circumferential direction and the z direction the axial direction. In the cylindrical coordinate system, the rθ plane coincides with the xy plane, and the z direction coincides with the z direction of the Cartesian coordinate system. The structure 5 has an elastic part group 3, which is a group of multiple elastic parts discretely arranged in the virtual plane P. The elastic part group 3 has at least four elastic parts 31, 32, 33, and 34 discretely arranged in the virtual plane P. In other words, the number of elastic parts included in the elastic part group 3 that are discretely arranged in the virtual plane P is four or more. The sensor 10 may have one or more elastic parts that are not located within the virtual plane P on which the elastic part group 3 is arranged. However, one or more elastic parts that are not located within the virtual plane P are not counted as elastic parts of the elastic part group 3 located within the virtual plane P.

[0011] The structure 5 includes at least one metal part 51. The one metal part 51 has at least two elastic parts 31, 32, out of four elastic parts 31, 32, 33, 34. In other words, the elastic parts 31, 32 are part of the one metal part 51.

[0012] The area within which the metallic bonds of metal atoms in a metal part are continuous is contained within a single metal part. However, between two metal parts that are only fastened together by screws or glued together, the metallic bonds are discontinuous, and therefore the two metal parts are separate.

[0013] The metal material constituting the metal part 51 is either a single metal or a mixture (alloy) of metals. The metal part 51 may also be a base material made of metal material that has been plated. In order to ensure the rigidity of the structure 5, it is preferable that the metal part 51 is hard, for example, a metal material with a Vickers hardness of 90 HV or higher. The material of the metal part 51 can be iron alloys (steel) such as carbon steel and alloy steel, or aluminum alloys, titanium alloys, etc., but in terms of material cost, iron alloys are preferred.

[0014] A single metal part 51 may have an upper surface portion 1 and a lower surface portion 2 facing the upper surface portion 1. At least two elastic portions 31, 32 (in this example, four elastic portions 31-34) are provided so that the plane P is located between the upper surface portion 1 and the lower surface portion 2. In the following description, the terms "up" and "down" simply correspond to the + and - sides in the z direction, and there is no need to align the z direction with the vertical direction when the sensor 10 is in use. The upper surface portion 1 may also be referred to as the front surface, and the lower surface portion 2 as the back surface.

[0015] The detection means 8 includes one or more detectors. The detectors of the detection means 8 may include multiple parts 6 and 7. As the structure 5 deforms, the relative positional relationship between parts 6 and 7 changes, and this relative positional relationship can be detected by parts 6 and 7. The detectors of the detection means 8 are, for example, encoders including a head and a scale, where an example of part 6 is the head and an example of part 7 is the scale. Part 6 may be the scale and part 7 may be the head. In addition to parts 6 and 7, the detection means 8 may include a component that processes the signal output from part 6 or part 7. The encoder of the detection means 8 may be an optical encoder or a magnetic encoder. If an optical encoder is used as the detection means 8, the magnetic constraints of the metal part 51 are small. The head of the optical encoder has at least a light-receiving part and may optionally have a light-emitting part that emits light to illuminate the scale. Here, an example is shown where parts 6 and 7 face each other in the z-direction, but parts 6 and 7 may face each other in the x-direction, y-direction, r-direction, or θ-direction. The encoder as the detection means 8 may be a linear encoder or a rotary encoder. The output method may be incremental or absolute. The encoder can be configured such that parts 6 and 7 move relative to each other in a direction orthogonal to the direction in which they face each other. By adopting a configuration in which parts 6 and 7 move relative to each other in the direction in which they face each other, a change in the distance between parts 6 and 7 may be detected optically, magnetically, or electrostatically. For example, the detector of the detection means 8 may be a capacitive displacement sensor. Alternatively, the detector of the detection means 8 may be a strain gauge, and the strain gauge may be attached to at least one of the elastic parts of the elastic part group 3 of the structure 5 to detect the deformation of the structure 5.

[0016] Structure 5 includes reinforcing parts 56 and 57. Reinforcing part 56 is positioned on one side (+z side) in the z-direction with respect to plane P, and reinforcing part 57 is positioned on the other side (-z side) in the z-direction with respect to plane P. Plane P may be located between reinforcing parts 56 and 57. In this example, a metal part 51 is located between reinforcing parts 56 and 57. Reinforcing part 56 is coupled to metal part 51, and reinforcing part 57 is also coupled to metal part 51. More specifically, reinforcing part 56 is coupled to the upper surface 1 of metal part 51, and reinforcing part 57 is coupled to the lower surface 2 of metal part 51. In this example, metal part 51 is located between reinforcing parts 56 and 57. However, at least one of reinforcing parts 56 and 57 may be located between the upper surface 1 and the lower surface 2. For example, the reinforcing part 56 may be positioned on the side of the lower part 2 relative to the upper part 1 and connected to the upper part 1, or the reinforcing part 57 may be positioned on the side of the upper part 1 relative to the lower part 2 and connected to the lower part 2.

[0017] The force that the detection means 8 attempts to detect is called the target force, and forces acting in a direction different from the direction in which the target force is applied are called non-target forces. For example, when the detection means 8 attempts to detect a force acting in the θ direction, forces acting in the r and z directions are non-target forces. Non-target forces can also be called multi-axial forces. Non-target forces become a disturbance factor in the detection of the target force. Disturbances in the detection of the target force due to multi-axial forces are called multi-axial interference. This is advantageous in reducing the influence of multi-axial interference and improving the detection accuracy of the target force of the sensor 10. Because the structure 5 includes reinforcing parts 56 and 57 that reinforce the metal part 51, the rigidity of the structure 5 against non-target forces is increased, thus improving the detection accuracy of the target force of the sensor 10.

[0018] Sensor 10 can be a force sensor. Here, the force detected by the force sensor (target force) is at least one of the following: a force in the x direction, a force in the y direction, a force in the z direction, a force around the x axis, a force around the y axis, and a force around the z axis. The force around the z axis in the rθz cylindrical coordinate system described above is a force in the θ direction. If sensor 10 detects f (f≦6) of the six forces, sensor 10 can be called an f-axis force sensor. If sensor 10 exclusively detects at least one of the forces around the x axis, a force around the y axis, and a force around the z axis, sensor 10 can be called a torque sensor. If sensor 10 detects only a force around the z axis, it can be called a single-axis force sensor or a single-axis torque sensor.

[0019] If the detection means 8 includes multiple detectors, these multiple detectors can be configured to detect forces in the same direction. By statistically processing the outputs of the multiple detectors, the influence of characteristic variations between detectors can be reduced, thereby improving the detection accuracy of the sensor 10. Here, statistical processing involves extracting the maximum value, minimum value, average value, sum value, median value, etc., from the output of each detector in the multiple detectors. In the case of E detectors (where E is an even number), the median can be the E / 2th or (E / 2)+1th largest value.

[0020] Figure 1(b) shows a first arrangement example of the four elastic parts 31-34 when viewed from the z direction on a hypothetical plane P. In the first arrangement example, the four elastic parts 31-34 are arranged in a one-dimensional manner. In Figure 1(b), the dashed lines connecting the elastic parts 31-34 indicate that these elastic parts 31, 32, 33, and 34 are contained within a single metal part 51. At least one detector 81 is provided on the metal part 51.

[0021] Figure 1(c) shows a second arrangement example of the four elastic parts 31, 32, 33, and 34 when viewed from the z direction on a hypothetical plane P. In the second arrangement example, the four elastic parts 31, 32, 33, and 34 are arranged in two dimensions. In Figure 1(c), the dashed line connecting elastic parts 31 and 32 indicates that the elastic parts 31 and 32 are contained within a single metal part 51. In Figure 1(c), the dashed line connecting elastic parts 33 and 34 indicates that the elastic parts 33 and 34 are contained within a single metal part 52. The fact that there is no dashed line connecting elastic part 31 to elastic part 33 and elastic part 34, and that there is no dashed line connecting elastic part 32 to elastic part 33 and elastic part 34, indicates that metal part 51 and metal part 52 are separate metal parts. In other words, the metal part 52 has two elastic parts 33 and 34 that are separate from the two elastic parts 31 and 32 that the metal part 51 has, out of the four elastic parts 31 to 34.

[0022] In the second arrangement example, at least one detector 81 is provided for the metal component 51, and at least one detector 82 is provided for the metal component 52.

[0023] Figure 2(a) shows a third arrangement example of the four elastic parts 31, 32, 33, and 34 when viewed from the z direction on a hypothetical plane P. In this third arrangement example, the four elastic parts 31 to 34 are arranged in plane P such that a hypothetical circle 304 passes through the four elastic parts 31 to 34. Such an arrangement is advantageous for detecting deformation occurring in the θ direction (circumferential direction) in a cylindrical coordinate system. Alternatively, it is also advantageous for detecting deformation occurring in the x and y directions in a Cartesian coordinate system. Furthermore, in this third arrangement example, one metal part 51 has four elastic parts 31 to 34. In this third arrangement example, at least four detectors 81, 82, 83, and 84 are provided on the metal part 51.

[0024] Figure 2(b) shows a fourth arrangement example of the four elastic parts 31, 32, 33, and 34 when viewed from the z-direction on a hypothetical plane P. The fourth arrangement example differs from the third arrangement example in that the elastic parts 31 and 32 are housed in one metal part 51, and the elastic parts 33 and 34 are housed in one metal part 51. In the fourth arrangement example, at least two detectors 81 and 82 are provided on the metal part 51, and at least two detectors 83 and 84 are provided on the metal part 52. Other aspects may be the same as in the third arrangement example.

[0025] Figure 2(c) shows a fifth arrangement example of the arrangement of at least six elastic parts when viewed from the z direction on a virtual plane P. In the fifth arrangement example, the at least six elastic parts include elastic parts 35, 36, 37, and 38 in addition to the four elastic parts 31 to 34 described above, for a total of eight elastic parts 31, 32, 33, 34, 35, 36, 37, and 38. In the fifth arrangement example, one metal part 51 has at least six of the eight elastic parts 31 to 38 (e.g., elastic parts 31 to 36) and eight of the eight elastic parts 31 to 38. In the fifth arrangement example, the six elastic parts (e.g., elastic parts 31 to 36) are arranged in plane P such that a virtual circle 306 passes through at least six elastic parts (e.g., elastic parts 31 to 36). In this example, the virtual circle 306 passes through eight elastic parts 31 to 38.

[0026] Figure 2(d) shows a sixth arrangement example of at least six elastic parts when viewed from the z direction on a hypothetical plane P. In the sixth arrangement example, one metal part 51 has four of the eight elastic parts 31 to 38, and another metal part 52 has four of the eight elastic parts 35 to 38.

[0027] In Figures 2(a) to 2(d), each elastic part included in the elastic part group 3 deforms, for example, in the θ direction, allowing the detectors 81 to 84 included in the detection means 8 to detect the force in the θ direction as torque. Alternatively, each elastic part included in the elastic part group 3 deforms in the x or y direction, allowing the force in the x or y direction to be detected.

[0028] As described above, in this embodiment, the sensor 10 has one metal part 51 which has at least two elastic parts 31 and 32 among the four elastic parts 31 to 34.

[0029] Sensor 10 can be mounted on various types of mechanical equipment. These types of mechanical equipment may include a prime mover (electric motor) such as a motor or engine, and sensor 10. The prime mover operates the sensor 10 relative to the second link. Examples of mechanical equipment include imaging equipment such as cameras, optical equipment such as lenses, office equipment such as printers and copiers, medical equipment such as CT scanners and MRI machines, industrial equipment such as robots and exposure machines, and transportation equipment such as vehicles, ships, and airplanes. Vehicles may include automobiles, bicycles, and railway vehicles. Furthermore, these types of mechanical equipment may also be medical or nursing care equipment such as powered suits and prosthetic limbs. By mounting sensor 10, which measures mechanical quantities, on these mechanical devices and measuring the forces generated in and around the movable parts, the operation of these mechanical devices can be controlled.

[0030] Figures 3(a) and 3(b) illustrate an example of how the sensor 10 is used. The mechanical device 1000 equipped with the sensor 10 includes a link 630 and a link 640. A link is a mechanical element that operates relative to another, and the connection between links is a joint. For example, links 630 and 640 rotate relative to each other with axis 680 as the axis of rotation. The sensor 10 is provided between links 630 and 640. The sensor 10 is fixed to link 630 by a fixing member 650 such as a screw, and the sensor 10 is fixed to link 640 by a fixing member 660 such as a screw or bolt.

[0031] In the sensor 10 shown in Figure 3(a), the upper surface 1 of the metal part 51 is fixed to the link 640 by a fixing member 660, and the lower surface 2 of the metal part 51 is fixed to the link 630 by a fixing member 650. In the sensor 10 shown in Figure 3(b), the reinforcing part 56 fixed to the upper surface 1 is fixed to the link 640 by a fixing member 660, and the reinforcing part 57 fixed to the lower surface 2 is fixed to the link 630 by a fixing member 650.

[0032] In recent years, robots 600 that operate according to robot programs have been used for the production of goods. For the production of goods that require precision in assembly operations, a control method is used in which sensors 10 capable of acquiring mechanical information such as torque are placed on the robot 600, and the robot's movement is controlled by measuring the force acting on the joints. Among this type of sensor 10, torque sensors have attracted attention, which use detection means capable of detecting the deformation of the structure 5 that constitutes the sensor 10, and detect the torque acting on the joints based on the detected deformation and the rigidity of the structure 5. The torsion of the rotation axis is considered as a force Mz on the rotation axis of the torque, and forces in other directions become multi-axial forces. Multi-axial forces become disturbances (multi-axial interference) in torque detection. The amount of torsion due to multi-axial interference becomes a disturbance factor in torque detection. Multi-axial interference can be reduced by providing an upper surface 1 and a lower surface 2, as well as reinforcing parts 56 and 57, on the structure 5.

[0033] Figures 4 and 5 schematically illustrate the method of torque detection using sensor 10. Figure 4 corresponds to the configuration in Figure 3(a), and Figure 5 corresponds to the configuration in Figure 3(b).

[0034] Figures 4(a) and 5(a) show the state where no torque is generated. This state is considered the initial position of parts 6 and 7 attached to the upper surface 1.

[0035] Figures 4(b) and 5(b) show, for example, the state in which shaft 680, shown in Figures 3(a) and 3(b), rotates and torque is generated. In this case, the upper part 1 connected to link 640 and the lower part 2 connected to link 630 are displaced in the rotational direction. Furthermore, the upper part 1 and the lower part 2 undergo elastic deformation, and the amount of this deformation is proportional to the magnitude of the generated torque.

[0036] Here, the positional relationship between parts 6 and 7 in Figures 4(b) and 5(b) shows a change of 930 from the initial position shown in Figures 4(a) and 5(b). Sensor 10 measures this change of 930 and detects the torque value based on the measured value. For this purpose, the rotational stiffness Gz [kNm / rad], which is the torque Nt [kNm] required to rotate sensor 10 by a unit angle [rad], is determined by measurement or the finite element method. Then, if the rotation angle measured by parts 6 and 7 is θ, the torque Nt is detected as Nt = Gz × θ [kNm]. In this respect, Figures 3(a) and 3(b) can similarly detect the target force.

[0037] Figures 4(c) and 5(c) show the state in which a bending moment 931 occurs as shown in Figures 3(a) and (b). In this case, as the upper surface 1 bends, part 6 is displaced to the left in the figure. This displacement causes a displacement 932 from the initial position in parts 6 and 7. This displacement due to the bending moment 931 may manifest as cross-axial interference, which can reduce the detection accuracy of the sensor.

[0038] In the configuration shown in Figure 5(c), the rigidity of the structure 5 is increased by the addition of reinforcing parts 56 and 57. Consequently, the displacement 933 of parts 6 and 7 from their initial positions when a bending moment 931 occurs is smaller than the displacement 933 in the configuration shown in Figure 4(c), and the effect of cross-axial interference is reduced.

[0039] The shape of the structure 5 will be specifically explained using Figure 6. The reinforcing part 56 has an overlapping part 561 that overlaps the elastic part 31, an overlapping part 562 that overlaps the elastic part 32, and a relay part 563 that connects the overlapping part 561 and the overlapping part 562. Similarly, the reinforcing part 57 has an overlapping part 571 that overlaps the elastic part 31, an overlapping part 572 that overlaps the elastic part 32, and a relay part 573 that connects the overlapping part 571 and the overlapping part 572. Here, "overlapping" of two parts means that the two parts are aligned in the z direction. Also, "connecting" means that one part "connects" two parts, which means that the two parts are continuous in the x, y, θ, or r direction via one part. The one part that "connects" two parts is not limited to being located between the two parts, but may also be located in a part that is not between the two parts.

[0040] Metal part 51 has a metal part 11 that overlaps with the overlapping part 561 and a metal part 12 that overlaps with the overlapping part 562. Metal part 51 has a metal part 21 that overlaps with the overlapping part 571 and a metal part 22 that overlaps with the overlapping part 562. The elastic part 31 connects metal part 11 and metal part 21. The elastic part 32 is located between metal part 12 and metal part 22. The elastic part 32 connects metal part 12 and metal part 22. The elastic part 31 is located between metal part 11 and metal part 21. Metal part 11 is located between the elastic part 31 and the overlapping part 561, and metal part 12 is located between the elastic part 32 and the overlapping part 562. Metal part 21 is located between the elastic part 31 and the overlapping part 571, and metal part 22 is located between the elastic part 32 and the overlapping part 572.

[0041] The metal part 51 has a metal portion 13. The metal portion 13 satisfies at least one of the following conditions: it overlaps with the intermediate portion 563 and it connects the elastic portion 31 and the elastic portion 32. The metal part 51 also has a metal portion 23. The metal portion 23 satisfies at least one of the following conditions: it overlaps with the intermediate portion 573 and it connects the elastic portion 31 and the elastic portion 32. A gap 30 is provided between the metal portion 13 and the metal portion 23. The gap 30 exists between the elastic portion 31 and the elastic portion 32 in the x, y, r, or θ direction. By providing the gap 30, the rigidity of the metal part 51 is reduced, and the elastic portions 31 and 32 undergo elastic deformation.

[0042] Metal parts 11, 12, and 13 constitute the upper surface 1 of the metal component 51. Metal parts 21, 22, and 23 constitute the lower surface 2 of the metal component 51.

[0043] The reinforcing part 56 has an extending part 564 that extends from the overlapping part 561 to the opposite side of the intermediate part 563, and an extending part 565 that extends from the overlapping part 562 to the opposite side of the intermediate part 563. Similarly, the reinforcing part 57 has an extending part 574 that extends from the overlapping part 571 to the opposite side of the intermediate part 573, and an extending part 575 that extends from the overlapping part 572 to the opposite side of the intermediate part 563.

[0044] Metal part 51 has a metal portion 14. The metal portion 14 satisfies at least one of the following: it overlaps with the extending portion 564, and it extends from the metal portion 11 to the side opposite to the metal portion 13. Metal part 51 has a metal portion 15. The metal portion 15 satisfies at least one of the following: it overlaps with the extending portion 565, and it extends from the metal portion 12 to the side opposite to the metal portion 13. Metal part 51 has a metal portion 24. The metal portion 24 satisfies at least one of the following: it overlaps with the extending portion 574, and it extends from the metal portion 21 to the side opposite to the metal portion 23. Metal part 51 has a metal portion 25. The metal portion 25 satisfies at least one of the following: it overlaps with the extending portion 575, and it extends from the metal portion 22 to the side opposite to the metal portion 23.

[0045] When the intermediate section 563 and the extended sections 564 and 565 overlap with the metal parts 51 (metal parts 13, 14, and 15), the intermediate section 563 and the extended sections 564 and 565 can also be referred to as overlapping sections. When the intermediate section 573 and the extended sections 574 and 575 overlap with the metal parts 51 (metal parts 23, 24, and 25), the intermediate section 573 and the extended sections 574 and 575 can also be referred to as overlapping sections. The intermediate section 563 and the extended sections 564 and 565, and the intermediate section 573 and the extended sections 574 and 575 do not necessarily overlap with the metal parts 51.

[0046] The reinforcing part 56 and the metal part 51 are joined by a joint 58, and the reinforcing part 57 and the metal part 51 are joined by a joint 59. The joining by the joint 58 can take various forms, such as by adhesive, welding, or fastening. When the reinforcing parts 56 and 57 are metal parts, the joining of the reinforcing parts 56 and 57 to the metal part 51 is preferably by welding, in which case the joints 58 and 59 can be called welded parts.

[0047] Figure 6 shows the thicknesses S1 of the overlapping section 561, S2 of the overlapping section 562, S3 of the overlapping section 571, and S4 of the overlapping section 572. Figure 6 also shows the thicknesses S5 of the intermediate section 563, S6 of the intermediate section 573, S7 of the extended section 564, S8 of the extended section 565, S9 of the extended section 574, and S10 of the extended section 575. Thicknesses S1 to S10 represent the dimensions of the reinforcing parts 56 and 57 in the z-direction. Larger thicknesses S1 to S10 indicate higher rigidity of the reinforcing parts 56 and 57 in the z-direction. At least two of the thicknesses S1 to S10 may be different, but at least two of the thicknesses S1 to S10 may be equal; in this example, thicknesses S1 to S10 are all assumed to be equal. If the maximum value of thicknesses S1 to S10 is less than 110% of the minimum value, then in this example, thicknesses S1 to S10 can all be considered equal, and in that case, at least two of the larger thicknesses S1 to S10 will be less than 110% of the smaller one.

[0048] Figure 6 shows the thickness T1 of the elastic part 31 and the thickness T2 of the elastic part 32, respectively. Thicknesses T1 and T2 are the dimensions of the elastic parts 31 and 32 of the metal part 51 in the x, y, r, or θ directions. The smaller the thicknesses T1 and T2, the lower the rigidity of the metal part 51 in the x, y, r, or θ directions. When thicknesses T1 and T2 are small in a given direction, the rigidity of the elastic parts 31 and 32 decreases, making the elastic parts 31 and 32 more susceptible to elastic deformation in that direction. Thicknesses T1 and T2 may be different from each other, or they may be equal. In this example, we will assume that thicknesses T1 and T2 are equal. In this example, if the larger of the two thicknesses T1 and T2 is less than 110% of the smaller of the two, T1 and T2 can be considered equal.

[0049] Figure 6 shows the thicknesses T3 of metal part 13, T4 of metal part 23, T5 of metal part 14, T6 of metal part 15, T7 of metal part 24, and T8 of metal part 25, respectively. Thicknesses T3 to T8 are dimensions in the z-direction of the upper surface portion 1 of the metal part 51, and the smaller the thickness T3 to T8, the lower the rigidity of the metal part 51 in the z-direction. Thicknesses T3 to T8 may be different from each other, or they may be equal, and in this example, we will explain assuming that thicknesses T3 to T8 are equal. If the maximum value of thicknesses T3 to T8 is less than 110% of the minimum value, then in this example, we may consider all thicknesses T3 to T8 to be equal, in which case at least two of the larger thicknesses T3 to T8 will be less than 110% of the smaller one.

[0050] Figure 6 shows the distance G1 between the overlapping portion 561 and the metal part 51 (metal part 11), and the distance G2 between the overlapping portion 562 and the metal part 51 (metal part 12). Also in Figure 6, the distance G3 between the overlapping portion 571 and the metal part 51 (metal part 21), and the distance G4 between the overlapping portion 572 and the metal part 51 (metal part 22). Furthermore, Figure 6 shows the distance G5 between the intermediate portion 563 and the metal part 51 (metal part 13), and the distance G6 between the intermediate portion 573 and the metal part 51 (metal part 23). Distances G1 to G6 may be different from each other, or they may be equal to each other; in this example, we will assume that distances G1 to G6 are equal. If the maximum value of distances G1 to G6 is less than 110% of the minimum value, then in this example, distances G1 to G6 may all be considered equal, in which case at least two of the larger distances G1 to G6 will be less than 110% of the smaller one. At least one of the distances G1 to G6 may be zero, that is, at least one of the overlapping portions 561, 562, 571, 572 and the intermediate portions 563, 573 may be in contact with the metal part 51. However, it is preferable that the distances G1 to G6 are greater than zero. Even if some part of each of the overlapping portions 561, 562, 571, 572 and the intermediate portions 563, 573 is in contact with the metal part 51, it is preferable that other parts of each of the overlapping portions 561, 562, 571, 572 and the intermediate portions 563, 573 are away from the metal part 51. In this example, a gap 1056 is provided between the reinforcing part 56 and the metal part 51, and a gap 2057 is provided between the reinforcing part 57 and the metal part 51. It is preferable that the distances G1 to G6 are the distances between the reinforcing parts 56, 57 and the metal part 51 through these gaps 1056, 2057.

[0051] Figure 6 shows the distance D1 between overlapping section 561 and overlapping section 571, the distance D2 between overlapping section 562 and overlapping section 572, the distance D3 between relay section 563 and relay section 573, and the distance D4 between metal section 13 and metal section 23. Distances D1 to D3 may be different from each other, or they may be equal. In this example, we will assume that distances D1 to D3 are equal. If the maximum value of distances D1 to D3 is less than 110% of the minimum value, then in this example, distances D1 to D3 may all be considered equal. In that case, at least two of the larger distances D1 to D3 will be less than 110% of the smaller one.

[0052] In this embodiment, reinforcing parts 56 and 57 are provided to reinforce the upper surface 1 and lower surface 2 so that they do not undergo elastic deformation as much as possible when the elastic parts 31 and 32 undergo elastic deformation. It is desirable that the rigidity of the reinforcing parts 56 and 57 be higher than that of the elastic parts 31 and 32, which provide elasticity (have reduced rigidity) in the structure 5. From this viewpoint, the thicknesses S1 to S10 of each part of the reinforcing parts 56 and 57 can be set to be larger than the thicknesses T1 and T2 of the elastic parts 31 and 32 ([S1 to S10] > [T1 and T2]). For example, the thickness S5 of the intermediate part 563 is greater than the thickness T1 of the elastic part 31 (S5 > T1), and the thickness S6 of the intermediate part 573 is greater than the thickness T2 of the elastic part 32 (S6 > T2).

[0053] The reinforcing parts 56 and 57 are particularly effective when the rigidity of the upper surface 1 and lower surface 2 is insufficient. It is desirable that the rigidity of the reinforcing parts 56 and 57 be higher than that of the upper surface 1 and lower surface 2 which provide rigidity to the structure 5. In this regard, the thicknesses S1 to S10 of each part of the reinforcing parts 56 and 57 can be set to be greater than the thicknesses T3 to T8 of the upper surface 1 and lower surface 2 corresponding to each part of the reinforcing parts 56 and 57 ([S1 to S10] > [T3 to T8]). For example, the thickness S5 of the intermediate part 563 is greater than the thickness T3 of the metal part 13 (S5 > T3), and the thickness S6 of the intermediate part 573 is greater than the thickness T4 of the metal part 23 (S6 > T4).

[0054] Because reinforcing parts 56 and 57 are provided, the thicknesses T1 to T8 of each part of the upper surface 1 and lower surface 2 may be closer to the thicknesses T1 and T2 of the elastic parts 31 and 32 than the thicknesses S1 to S10 of each part of the reinforcing parts 56 and 57 corresponding to each part of the upper surface 1 and lower surface 2. That is, the difference between the thicknesses T1 and T2 of the elastic parts 31 and 32 and the thicknesses T3 to T8 of each part of the upper surface 1 and lower surface 2 may be smaller than the difference between the thicknesses S1 to S10 of each part of the reinforcing parts 56 and 57 and the thicknesses T3 to T8 of each part of the upper surface 1 and lower surface 2 corresponding to each part of the reinforcing parts 56 and 57 (|[T3~T8]-[T1&T2]|<|[S1~S10]-[T3~T8]|). For example, the difference between the thickness T1 of the elastic part 31 and the thickness T3 of the metal part 13 is smaller than the difference between the thickness S5 of the intermediate part 563 and the thickness T3 of the metal part 13. Furthermore, the difference between the thickness T2 of the elastic part 32 and the thickness T4 of the metal part 23 is smaller than the difference between the thickness S6 of the intermediate part 573 and the thickness T4 of the metal part 23.

[0055] Furthermore, in order to impart appropriate elasticity to the elastic parts 31 and 32 and appropriate rigidity to the upper surface part 1 and lower surface part 2, it is preferable that the thicknesses T1 and T2 of the elastic parts 31 and 32 are smaller than the thicknesses T3 to T8 of each part of the upper surface part 1 and lower surface part 2 ([T1&T2]<[T3~T8]). However, if appropriate elasticity and rigidity are imparted to the elastic parts 31 and 32, the rigidity of the structure 5 can be provided by the reinforcing parts 56 and 57 even if the rigidity of the upper surface part 1 and lower surface part 2 is small. Therefore, the thicknesses T1 and T2 of the elastic parts 31 and 32 may be equal to the thicknesses T3 to T8 of each part of the upper surface part 1 and lower surface part 2 ([T1&T2]=[T3-T8]), or they may be larger than the thicknesses T3 to T8 of each part of the upper surface part 1 and lower surface part 2 (([T1&T2]>[T3-T8])). By making the thicknesses T3 to T8 of the upper surface 1 and lower surface 2 the same as or smaller than the thicknesses T1 and T2 of the elastic parts 31 and 32, the cost of the metal part 51 having the elastic parts 31 and 32 can be reduced. If the thicknesses T1 and T2 of the elastic parts 31 and 32 are equal to the thicknesses T3 to T8 of the upper surface 1 and lower surface 2, then the difference between the thicknesses T1 and T2 of the elastic parts 31 and 32 and the thicknesses T3 to T8 of the upper surface 1 and lower surface 2 is zero.

[0056] The elasticity of the metal part 51 is largely determined by the thicknesses T1 and T2 of the elastic parts 31 and 32 and the lengths of the elastic parts 31 and 32. The lengths of the elastic parts 31 and 32 (dimension in the z direction) can correlate with the distance D4 between the metal part 13 and the metal part 23. The larger the distance D4 between the metal part 13 and the metal part 23, the lower the rigidity of the metal part 51 may be. In this example, the lengths of the elastic parts 31 and 32 coincide with the distance D4 between the metal part 13 and the metal part 23. On the other hand, the smaller the distance G1 to G3 between the reinforcing parts 56 and 57, the higher the rigidity of the structure 5 may be. In order to increase the rigidity of the structure 5 while decreasing the rigidity of the metal part 51, it is preferable that the distance D4 between the metal part 13 and the metal part 23 is 2 / 3 or more of the distance G1 to G3 between the reinforcing parts 56 and 57. For example, it is preferable that the distance G1 between overlapping portion 561 and overlapping portion 571 is 2 / 3 or more of the length of elastic portion 31, and that the distance G2 between overlapping portion 562 and overlapping portion 572 is 2 / 3 or more of the length of elastic portion 32. Also, it is preferable that the distance D4 between metal portion 13 and metal portion 23 is 2 / 3 or more of the distance D3 between relay portion 563 and relay portion 573 (D4 ≥ D3 × 2 / 3).

[0057] If the thicknesses S1 to S10 of each part of the reinforcing components 56 and 57 are made extremely large, it will lead to an increase in the size, weight, and cost of the structure 5.

[0058] The thicknesses S1 to S10 of each part of the reinforcing parts 56 and 57 are preferably smaller than the distances D1 to D3 between the reinforcing part 56 and the reinforcing part 57. For example, the thickness S1 of the overlapping part 561 is smaller than the distance D1 between the overlapping part 561 and the overlapping part 571 (S1 < D1), and the thickness S3 of the overlapping part 571 is smaller than the distance D1 between the overlapping part 561 and the overlapping part 571 (S1 < D1). The thickness S5 of the relay part 563 is smaller than the distance D3 between the relay part 563 and the relay part 573 (S5 < D5), and the thickness S6 of the relay part 573 is smaller than the distance D3 between the relay part 563 and the relay part 573 (S6 < D3). Further, the thicknesses S1 to S10 of each part of the reinforcing parts 56 and 57 may be smaller than the lengths of the elastic parts 31 and 32, or may be smaller than the distance D4 between the metal part 13 and the metal part 23 ([S1 to S10] < D4). For example, the thickness S5 of the relay part 563 is smaller than the distance D4 between the metal part 13 and the metal part 23 (S5 < D4), and the thickness S6 of the relay part 573 is smaller than the distance D4 between the metal part 13 and the metal part 23 (S6 < D4).

[0059] In order for the reinforcing parts 56 and 57 to effectively act on (reinforce) the metal part 51, it is preferable to arrange the reinforcing parts 56 and 57 as close as possible to the metal part 51. Therefore, the distances G1 to G6 between each part of the reinforcing parts 56 and 57 and the upper surface part 1 and the lower surface part 2 of the metal part 51 are preferably smaller than the distance between the upper surface part 1 and the lower surface part 2. For example, the distance G3 between the relay part 563 and the metal part 13 is smaller than the distance D4 between the relay part 563 and the relay part 573 (G3 < D4), and the distance G6 between the relay part �63 and the metal part 23 is smaller than the distance D4 between the relay part 563 and the relay part 573 (G6 < D4).

[0060] Also, the distances G1 to G6 between each part of the reinforcing parts 56 and 57 and the upper surface part 1 and the lower surface part 2 of the metal part 51 are preferably smaller than the thicknesses (S1 to S10) of each part of the reinforcing parts 56 and 57 corresponding to each part of the upper surface part 1 and the lower surface part 2. For example, the distance G3 between the relay part 563 and the metal part 13 is smaller than the thickness S3 of the relay part 563 (G3 < S3), and the distance G6 between the relay part 573 and the metal part 23 is smaller than the thickness S6 of the relay part 573 (G6 < S6).

[0061] Also, the distances G1 to G6 between each part of the reinforcing parts 56 and 57 and the upper surface part 1 and the lower surface part 2 of the metal part 51 are preferably smaller than the thicknesses (T3 to T8) of each part of the upper surface part 1 and the lower surface part 2 corresponding to each part of the reinforcing parts 56 and 57. For example, the distance G3 between the relay part 563 and the metal part 13 is smaller than the thickness T3 of the metal part 13 (G3 < T3), and the distance G6 between the relay part 573 and the metal part 23 is smaller than the thickness T4 of the metal part 23 (G6 < T4).

[0062] Also, the distances G1 to G6 between each part of the reinforcing parts 56 and 57 and the upper surface part 1 and the lower surface part 2 of the metal part 51 are preferably smaller than the thicknesses (T1, T2) of the elastic parts 31 and 32 ([G1 to G6] < [T1 & T2]). For example, the distance G1 between the overlapping part 561 and the metal part 51 (metal part 11) is smaller than the thickness T1 of the elastic part 31 (G1 < T1), and the distance G2 between the overlapping part 562 and the metal part 51 (metal part 12) is smaller than the thickness T2 of the elastic part 31 (G2 < T2). Also, the distance G3 between the overlapping part 571 and the metal part 51 (metal part 21) is smaller than the thickness T1 of the elastic part 31 (G3 < T1), and the distance G4 between the overlapping part 572 and the metal part 51 (metal part 22) is smaller than the thickness T2 of the elastic part 32 (G4 < T2). The distance G5 between the relay part 563 and the metal part 51 (metal part 13) is smaller than the thickness T1 of the elastic part 31 and the thickness T2 of the elastic part 32 (G5 < [T1 & T2]). The distance G6 between the relay part 573 and the metal part 51 (metal part 23) is smaller than the thickness T1 of the elastic part 31 and the thickness T2 of the elastic part 32 (G6 < [T1 & T2]).

[0063] The thicknesses S1 to S10 of each part of the reinforcing parts 56 and 57 may be between the lengths of the elastic parts 31 and 32, the distance D4 between the metal part 13 and the metal part 23, and the thicknesses of each part of the upper surface part 1 and the lower surface part 2. For example, the thickness S5 of the relay part 563 can be between the distance D4 between the metal part 13 and the metal part 23 and the thickness T3 of the metal part 13 (T3 < S5 < D4 or T3 > S5 > D4). Also, the thickness S6 of the relay part 573 can be between the distance D4 between the metal part 13 and the metal part 23 and the thickness T4 of the metal part 23 (T4 < S6 < D4 or T4 > S6 > D4). When both of the above-mentioned [S1 to S10] < D4 and [S1 to S10] > [T3 to T8] are satisfied, this relationship can also be satisfied.

[0064] The specific numerical ranges in the form described above are, for example, [G1 to G6] is 0 to 1 mm, [T1 & T2] is 1 to 3 mm, [T3 to T8] is 1 to 10 mm, [S1 to S10] is 1 to 20 mm, D4 is 5 to 15 mm, and D1 to D3 are 5 to 30 mm. Within this range, it is preferable to satisfy [G1 to G6] < [T1 & T2] ≤ [T3 to T8] < [S1 to S10] < D4 < [D1 to D3].

[0065] It is preferable that a gap is provided between each part of the reinforcing parts 56 and 57 and the upper surface part 1 and the lower surface part 2 of the metal part 51. For example, a gap 1056 is provided between the reinforcing part 56 and the metal part 51 (upper surface part 1). Also, a gap 2057 is provided between the reinforcing part 57 and the metal part 51 (lower surface part 2). That is, the reinforcing parts 56 and 57 and the metal part 51 (upper surface part 1 and lower surface part 2) can face each other through the gaps 1056 and 2057. The above-mentioned distances G1 to G6 can be the distances between the reinforcing parts 56 and 57 and the metal part 51 (upper surface part 1 and lower surface part 2) facing each other through the gaps 1056 and 2057.

[0066] If the reinforcing parts 56 and 57 are in contact with the upper surface 1 and lower surface 2 of the metal part 51, friction may occur between the reinforcing parts 56 and 57 and the metal part 51 when the structure 5 deforms. This friction may reduce the detection accuracy of the sensor 10. As described above, by providing gaps 1056 and 1057, friction between the reinforcing parts 56 and 57 and the metal part 51 can be reduced, and the detection accuracy of the sensor 10 can be improved. In the region where the reinforcing parts 56 and 57 and the metal part 51 overlap, it is preferable to maximize the area of ​​the gaps 1056 and 2057, but if gaps 1056 and 2057 are provided, there may be parts where the reinforcing parts 56 and 57 and the metal part 51 are in contact. It is preferable that the area in which the reinforcing parts 56 and the metal part 51 (upper surface 1) face each other via the gap 1056 is 25% or more of the area in the region where the reinforcing parts 56 and the metal part 51 (upper surface 1) overlap. The area in which the reinforcing part 56 and the metal part 51 (upper part 1) face each other via the gap 1056, relative to the area of ​​the overlapping region of the reinforcing part 56 and the metal part 51 (upper part 1), may be 75% or less, or 50% or less. The area in which the reinforcing part 57 and the metal part 51 (lower part 2) face each other via the gap 2057, relative to the area of ​​the overlapping region of the reinforcing part 57 and the metal part 51 (lower part 2), is preferably 25% or more. The area in which the reinforcing part 57 and the metal part 51 (lower part 2) face each other via the gap 2057, relative to the area of ​​the overlapping region of the reinforcing part 57 and the metal part 51 (lower part 2), may be 75% or less, or 50% or less.

[0067] Various methods can be employed to form the gaps 1056 and 2057. For example, a projection can be provided on one of the surfaces of the reinforcing parts 56 and 57 facing the metal part 51, and on the surface of the metal part 51 facing the reinforcing parts 56 and 57, and this projection can be brought into contact with the other. This makes it possible to form gaps 1056 and 2057 corresponding to the height of the projection. Multiple projections can also be provided on one of the surfaces of the reinforcing parts 56 and 57 facing the metal part 51, and on the surface of the metal part 51 facing the reinforcing parts 56 and 57, in which case gaps 1056 and 2057 can be formed between the multiple projections. Alternatively, a recess can be provided on one of the surfaces of the reinforcing parts 56 and 57 facing the metal part 51, and on the surface of the metal part 51 facing the reinforcing parts 56 and 57. This makes it possible to form gaps 1056 and 2057 corresponding to the depth of the recess. Alternatively, spacing-defining components (spacers, shims) can be placed between the reinforcing components 56, 57 and the metal component 51 to define the distance between them. This allows for the formation of gaps 1056, 2057 corresponding to the thickness of these spacing-defining components.

[0068] The sizes of the gaps 1056 and 2057 can be set so that even if the structure 5 (metal part 51, reinforcing parts 56 and 57) deforms, the metal part 51 (upper part 1, lower part 2) and the reinforcing parts 56 and 57 do not come into contact. For example, if the amount of deformation in the z direction of the upper part 1, lower part 2 and reinforcing parts 56 and 57, which is expected when using the sensor 10 in normal conditions, is known, then the dimensions of the gaps 1056 and 2057 in the z direction should be made larger than that amount of deformation. The dimensions of the gaps 1056 and 2057 in the z direction may be 1 μm or more, 1 mm or less, 10 to 100 μm, or 10 to 50 μm.

[0069] <First Embodiment> A first embodiment of the sensor 10 will be described using Figure 7. Figure 7(a) is a perspective view showing an example of the configuration of the sensor 10 excluding the reinforcing parts 56 and 57 shown in Figure 7(b), and Figure 7(c) is a cross-sectional view of the sensor 10 including the reinforcing parts 56 and 57.

[0070] As shown in Figure 7(a), the sensor 10 consists of a metal part 51 and a detection means 8 which is an optical encoder. Two of the detection means 8, which are optical encoders, are arranged at opposing positions on a circle centered on a rotation axis 503 on which torque acts on the metal part 51. The detection means 8 includes a part 7 which is a scale and a part 6 which is a head.

[0071] The metal part 51 is composed of an upper surface portion 1, a lower surface portion 2, and a group of elastic parts 3 including a plurality (8) of elastic parts arranged radially to connect the two. In the example shown in Figure 7, the upper surface portion 1 is provided with a holding part 77 for holding the scale (part 7). The upper surface portion 1 and the lower surface portion 2 are configured to be fastened to a measuring object that undergoes relative displacement. The upper surface portion 1 is provided with fixing or positioning holes 100, and the lower surface portion 2 is also provided with fixing or positioning holes 200.

[0072] The reinforcing parts 56 and 57 shown in Figure 7(b) are configured in the shape of a donut, bagel, or ring. The reinforcing parts 56 and 57 can form flange portions for fastening to a measuring object that undergoes relative displacement, such as the links 640 and 630 in Figure 3. The reinforcing parts 56 and 57 also have multiple holes 560 and 570 (e.g., screw holes or tapped holes) (12 in this example) which serve as fastening points for fastening to the links 640 and 630, respectively. The holes 560 and 570 can also be used to connect the reinforcing parts 56 and 57 to the upper surface 1 and the lower surface 2. The reinforcing parts 56 and 57 are provided with projections 1156 and 2157 with a height of less than 1 mm. As shown in Figure 7(c), gaps 1056 and 2057 corresponding to the height of the projections 1156 and 2157 are formed between the reinforcing parts 56 and 57 and the metal part 51. A gap 1056 is provided between multiple protrusions 1156, and a gap 2057 is provided between multiple protrusions 2157.

[0073] Each part of the metal component 51 is made of a predetermined metal (steel, stainless steel, etc.) having an elastic (spring) coefficient corresponding to the desired torque detection range and its required resolution. The metal component 51 is formed by machining a metal member.

[0074] The elastic group 3 is configured, for example, as a rib-shaped portion connecting a circular or ring-shaped upper surface 1 and a lower surface 2. These multiple elastic groups 3 are arranged radially around a rotating shaft 503 on which torque is applied.

[0075] For example, the elastic group 3 is arranged radially at multiple locations (eight in this example) with respect to the rotating shaft 503 on which the torque acts.

[0076] The detection means 8, which is an optical encoder, functions as an optical position sensor (encoder). The optical encoder comprises a scale (part 7) and a detection head (part 6) that detects position information from the scale. The detection head (part 6) constitutes an optical detection unit that detects the relative rotational displacement of the upper surface 1 and the lower surface 2.

[0077] Component 7 (scale) and component 6 (detection head) are mounted on the upper surface 1 and lower surface 2, respectively, via retaining component 77 and retaining component 66. Component 7 (scale) is fixed to the metal component 51 via retaining component 77, and component 6 (detection head) is fixed to the metal component 51 via retaining component 66.

[0078] In this example, the retaining part 77 is fixed to the support part 512 of the metal part 51. As shown in Figure 7(c), the entire support part 512 has a recessed shape provided on the upper surface 1. The outer circumference of this recess is a notch (opening) for facing parts 7 and 6.

[0079] Furthermore, the holding component 66 is fixed to the lower surface portion 2 of the metal component 51. Component 7, which is the detection head, is composed of a reflective optical sensor equipped with a light-emitting element and a light-receiving element (not shown). A scale pattern (details not shown) is arranged on the patterned surface of component 7 (scale) facing component 6 (detection head). This scale pattern is formed, for example, by arranging elements with regularly varying shades and reflectivity in a specific pattern.

[0080] Furthermore, depending on the detection calculation method, this scale pattern can consist of not only one line, but also multiple lines of varying intensity (for example, with different placement phases). The pitch of the scale pattern is determined according to the resolution required for position detection, but in recent years, with the increasing precision and resolution of encoders, pitches on the order of micrometers have become available.

[0081] The detection head emits light from a light-emitting element onto the scale, and the light reflected by the scale is received by a photodetector. Here, a torque acts around the rotation axis 503, and as the metal part 51 deforms around the rotation axis, the relative position of the detection head and the scale changes, causing the irradiation position of the light illuminating the scale to move across the scale.

[0082] At this time, when the light illuminating the scale passes through a pattern provided on the scale, the amount of light detected by the light-receiving element of the detection head changes. From this change in light intensity, the relative movement between the scale and the detection head is detected. The amount of movement detected by the detection head is converted into torque acting on the metal part 51 by a torque detection control unit (not shown) configured by a control routine executed by the CPU. Note that this torque detection control may be configured by a torque detection control unit configured by hardware. The output value (amount of movement) of the detection head is converted into a torque detection value by the above-mentioned torque detection control unit using a sensitivity coefficient that converts the amount of movement detected by the detection head into torque acting on the metal part 51.

[0083] As described above, the sensor 10 can detect the torque around the rotation axis 503 on which the torque acts.

[0084] The thickness Ta of the upper surface portion 1 shown in FIG. 7(c) corresponds to the thicknesses T3, T5, T6 in FIG. 6, and the thickness Tb of the lower surface portion 2 corresponds to the thicknesses T4, T7, T8 in FIG. 6. The thickness Sa of the reinforcing part 56 shown in FIG. 7(c) corresponds to the thicknesses S1, S2, S5, S7, S8 in FIG. 6, and the thickness Sb of the reinforcing part 57 corresponds to the thicknesses S3, S4, S6, S9, S10 in FIG. 6. The thickness Td of each elastic part of the elastic part group 3 shown in FIG. 7(c) corresponds to the thicknesses T1, T2 in FIG. 6. The height Hc of each elastic part of the elastic part group 3 shown in FIG. 7(c) corresponds to the distance D4 in FIG. 6. It is configured to satisfy Td < [Ta & Tb] < [Sa & Sb] < Hc. For example, Td = 1.6 mm, Ta = Tb = 3.2 mm, Sa = Sb = 4.8 mm, Hc = 9.6 mm.

[0085] <Second Embodiment> A second embodiment of the sensor 10 will be described with reference to FIGS. 8 and 9. In this embodiment, the elastic part group 3 in the structure 5 is composed of a plurality of block-shaped metal parts 51, 52, 53, 54. Each of the metal parts 51, 52, 53, 54 is formed by machining a metal member.

[0086] FIG. 8(a) is a perspective view of the metal parts 51, 52, 53, 54. Each of the metal parts 51, 52, 53, 54 has two elastic parts 31, 32, metal parts 11, 12, 13 that constitute the upper surface portion 1, and metal parts 21, 22, 23 that constitute the lower surface portion 2. A head unit 60 including an encoder head and a holding part for holding the head is fixed to the metal part 13, and a scale unit 70 including an encoder scale and a holding part for holding the scale is fixed to the metal part 23.

[0087] Figure 8(b) is an exploded view of the sensor 10. The sensor 10 has a structure in which four metal parts 51, 52, 53, and 54, each having two elastic parts 31 and 32, are sandwiched between reinforcing parts 56 and 57. The eight elastic parts are arranged so that a circle centered on the rotation axis of the sensor 10 passes through the eight elastic parts. The reinforcing parts 56 and 57 are provided with grooves 566 and 576 that are approximately the same width as the metal parts 51, 52, 53, and 54.

[0088] Figure 8(c) shows the metal parts 51, 52, 53, and 54 connected to the reinforcing part 57. The metal parts 51, 52, 53, and 54 are fitted into the grooves 576 of the reinforcing part 57, respectively. By fixing the reinforcing part 56 to the metal parts 51, 52, 53, and 54 in the state shown in Figure 8(c), a sensor 10 as shown in Figure 8(d) can be manufactured. For example, the hole 560 of the reinforcing part 56 and the holes 100 of the metal parts 51-54 are fixed with screws, and the hole 570 of the reinforcing part 57 and the holes 200 of the metal parts 51-54 are fixed with screws. Screw grooves can be formed in the metal parts 51-54.

[0089] Figure 9 shows a side view of the sensor 10 shown in Figure 8(d). Metal parts 51-54 are located between reinforcing part 56 and reinforcing part 57. In this example, the thicknesses S1 and S2 of the overlapping parts 561 and 562 and the thickness S5 of the relay part 563 are equal, but they may be different. The thicknesses S7 and S8 of the extending parts 564 and 565 are greater than the thicknesses S1 and S2 of the overlapping parts 561 and 562 and the thickness S5 of the relay part 563 ([S1&S2&S5]<[S7&S8]). The overlapping parts 561 and 562 corresponding to multiple metal parts 51-54 are connected by the extending parts 564 and 565, and the overlapping parts 571 and 572 corresponding to multiple metal parts 51-54 are connected (relayed) by the extending parts 574 and 575. For example, the extending portion 564 connects (relays) the overlapping portion 561 that overlaps the elastic portion 31 of metal part 51 and the overlapping portion 562 that overlaps the elastic portion 32 of metal part 52. For example, the extending portion 565 connects (relays) the overlapping portion 562 that overlaps the elastic portion 32 of metal part 51 and the overlapping portion 561 that overlaps the elastic portion 31 of metal part 54.

[0090] The distance D5 between the extended portion 564 and the extended portion 574 is less than the distance D1 between the overlapping portion 561 and the overlapping portion 571, and the distance D6 between the extended portion 565 and the extended portion 575 is less than the distance D2 between the overlapping portion 562 and the overlapping portion 572. The thicknesses S3 and S4 of the overlapping portions 571 and 572 and the thickness S6 of the intermediate portion 573 are equal, but may be different. The thicknesses S9 and S10 of the extended portions 574 and 575 are greater than the thicknesses S3 and S4 of the overlapping portions 571 and 572 and the thickness S6 of the intermediate portion 573 ([S3&S4&S6]<[S9&S10]). In this example, the distance between the overlapping portion 561 and the metal part 51 is zero, and the distance between the overlapping portion 572 and the metal part 51 is zero. In this embodiment, the friction between the metal parts 51-54 and the reinforcing parts 56 and 57 is reduced because the extended parts 564, 565, 574, and 575 do not come into contact with the metal parts 51-54. The thicknesses S5 and S6 of the intermediate parts 563 and 573 are greater than the thicknesses T3 and T4 of the metal parts 13 and 23 (S5 & S6 > T3 & T4). The difference between the thickness T1 of the elastic part 31 and the thickness T3 of the metal part 13 is greater than the difference between the thickness S5 of the intermediate part 563 and the thickness T3 of the metal part 13 (|T3-T1| > |S5-T3|). Also, the difference between the thickness T2 of the elastic part 32 and the thickness T4 of the metal part 23 is greater than the difference between the thickness S6 of the intermediate part 573 and the thickness T4 of the metal part 23. The distance D4 between metal part 13 and metal part 23 is between 1 / 4 and 1 / 2 of the distance D3 between relay part 563 and relay part 573 (D3 × 1 / 4 ≤ D4 ≤ D3 × 1 / 2).

[0091] In one example of this embodiment, the reinforcing parts 56 and 57 are annular in shape with an outer diameter of 100 to 200 mm and an inner diameter of 20 to 80 mm, with thicknesses S1 to S6 being 9 to 13 mm and thicknesses S7 to S10 being 13 to 17 mm. For the metal parts 51 to 54, T1 and T2 are 1 to 2 mm, T3 and T4 are 1 to 8 mm, D1 to D3 are 15 to 25 mm, D4 is 2 to 6 mm, and D5 and D6 are 10 to 20 mm.

[0092] <Third Embodiment> In this embodiment, a distinctive feature is that one metal part 51 is formed by bending a metal member. The metal member to be bent is a metal sheet, and the bending process is, for example, press working. In the manufacture of the metal part 51, various sheet metal processing methods such as punching, not just bending, can be used. By using bending compared to metal casting or machining, the productivity of the sensor can be improved. That is, with metal casting, sand molds are required to form complex shapes, making it unsuitable for mass production, and if molds are used, the cost of the molds is enormous for complex shapes. With machining, the base material is expensive, and the utilization rate of the base material is low, making it inefficient, and cutting using NC machining centers also requires long processing times. By using bending, a metal part 51 having at least two elastic parts can be manufactured with high throughput and low cost, thereby improving the productivity of the sensor 10. If the structure 5 is composed of a metal part 51 and a separate metal part 52, the metal part 52 may also be formed by bending a metal member.

[0093] This paper describes a configuration that is advantageous for ensuring sensor accuracy, using a structure formed by bending a metal component.

[0094] Figure 10(a) is a perspective view of an example of a single metal part 51 formed by bending a metal member, and Figure 10(b) is a side view of an example of a single metal part 51 formed by bending a metal member. Figure 10(b) shows virtual planes Pa, Pb, Pc, and Pd that are parallel to each other. Figure 10(c) is a perspective view of an example of a sensor 10 comprising a metal part 51 and detection means 8 (detectors 81-84). Figure 11(a) is a cross-sectional view of the metal part 51 in plane Pc, showing the structure of the metal part 51 in plane Pc. Figure 11(b) is a cross-sectional view of the metal part 51 in plane Pd, showing the structure of the metal part 51 in plane Pd.

[0095] The metal component 51 has a substantially regular M-sided polygon contour 55 (see Fig. 11) in a plan view with respect to the planes Pa, Pb, Pc, and Pd. In this example, M = 12, that is, it has a substantially regular dodecagon contour 55. M ≥ 3 is acceptable, M = 4 is also acceptable, but preferably M ≥ 5, and preferably M ≤ 24. The larger M is, the closer the contour 55 of the metal component 51 approaches a circle, and the accuracy for detecting displacement in the θ direction improves. However, the larger M is, the more complicated the bending process described later becomes. Therefore, 5 ≤ M ≤ 24 is appropriate. From the perspective of symmetry, M is preferably a multiple of 2 (an even number). Furthermore, from the perspective of symmetry in the x direction and the y direction orthogonal to the x direction, M is more preferably a multiple of 4. To be close to a circle, it is preferable that M ≥ 6 considering that the circumference ratio is about 3. Considering the above, M = 8, 12, 16 are preferable. In the following description, the natural number M can be read as a positive real number m (M - 0.5 ≤ m < M + 0.5) that rounds to M.

[0096] As shown in Fig. 10(b), the metal component 51 has an upper surface portion 1 and a lower surface portion 2 facing the upper surface portion 1. The upper surface portion 1 is provided in the plane Pa. The lower surface portion 2 is provided in the plane Pb. The metal component 51 has eight elastic portions 31 to 38. As shown in Fig. 11(a), the eight elastic portions 31 to 38 are discretely arranged in the plane Pc. Also, as shown in Fig. 11(b), the eight elastic portions 31 to 38 are discretely arranged in the plane Pd. Eight elastic portions 31 to 38 arranged in the planes Pc and Pd are provided so that the planes Pc and Pd are located between the upper surface portion 1 and the lower surface portion 2.

[0097] As shown in Fig. 10(b), the metal component 51 has a side surface portion 4. The side surface portion 4 is connected to the upper surface portion 1 and the lower surface portion 2. The metal component 51 is bent by bending at the connection portion 41 between the upper surface portion 1 and the side surface portion 4. The metal component 51 is bent by bending at the connection portion 42 between the lower surface portion 2 and the side surface portion 4. Each of the elastic portions 31 to 38 is connected to the side surface portion 4, and the metal component 51 is bent by bending at the connection portion 43 between each of the elastic portions 31 to 38 and the side surface portion 4.

[0098] The upper surface portion 1 shown in Figure 10(b) is composed of multiple upper plate portions 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, and 112 arranged along the plane Pa, as shown in Figure 10(a). The multiple upper plate portions 101 to 112 are arranged within the plane Pa. In Figures 11(a) and (b), the multiple upper plate portions 101 to 112 arranged within the plane Pa are shown superimposed on the elastic portions 31 to 38, illustrating the positional relationship between the multiple upper plate portions 101 to 112 and the multiple elastic portions 31 to 38.

[0099] As shown in Figures 11(a) and (b), in each of the multiple upper plate sections 101 to 112, two adjacent upper plate sections are joined to each other by a joint 48. This joint 48 may be, for example, a welded joint formed by welding two adjacent upper plate sections together, or it may be an adhesive joint that bonds two adjacent upper plate sections together. For example, upper plate section 101 and upper plate section 102 of the multiple upper plate sections 101 to 112 are joined to each other by a joint 48 formed by welding. Upper plate section 102 and upper plate section 103 of the multiple upper plate sections 101 to 112 are joined to each other by a joint 48 formed by welding. Upper plate section 103 and upper plate section 104 of the multiple upper plate sections 101 to 112 are joined to each other by a joint 48 formed by welding.

[0100] The lower surface portion 2 shown in Figure 10(b) is composed of multiple lower plate portions 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, and 212 arranged along the plane Pb, as shown in Figure 10(a). The multiple upper plate portions 201 to 212 are arranged within the plane Pb. In Figures 11(a) and (b), the multiple lower plate portions 201 to 212 arranged within the plane Pb are shown superimposed on the elastic portions 31 to 38, illustrating the positional relationship between the multiple lower plate portions 201 to 212 and the multiple elastic portions 31 to 38.

[0101] As shown in Figures 11(a) and (b), in each of the multiple lower plate sections 201 to 212, two adjacent lower plate sections are joined to each other by a joint 49. This joint 49 may be, for example, a welded joint formed by welding two adjacent lower plate sections together, or it may be an adhesive joint that bonds two adjacent lower plate sections together. For example, lower plate section 201 and lower plate section 202 of the multiple lower plate sections 201 to 212 are joined to each other by a joint 49 formed by welding. Lower plate section 202 and lower plate section 203 of the multiple lower plate sections 201 to 212 are joined to each other by a joint 49 formed by welding. Lower plate section 203 and lower plate section 204 of the multiple lower plate sections 201 to 212 are joined to each other by a joint 49 formed by welding.

[0102] The metal part 51 of this embodiment has a structure in which the form of the metal part 51 shown in Figure 6 is repeatedly arranged in an annular shape. In the form shown in Figure 10(a), the elastic parts 31 and 32 correspond to the elastic parts 31 and 32 in Figure 6, and the elastic parts 33 to 38 also correspond to the elastic parts 31 and 32 in Figure 6. For example, the elastic parts 31, 33, 35, and 37 in the form shown in Figure 10(a) correspond to the elastic part 31 in Figure 6, and the elastic parts 32, 34, 36, and 38 in the form shown in Figure 10(a) correspond to the elastic parts 31 and 32 in Figure 6.

[0103] In the configuration shown in Figure 10(a), the upper plate portion 101 may correspond to the metal portion 11 in Figure 6, the upper plate portion 103 may correspond to the metal portion 12 in Figure 6, and the upper plate portion 102 may correspond to the metal portion 13 in Figure 6. Also, in the configuration shown in Figure 10(a), the lower plate portion 201 may correspond to the metal portion 21 in Figure 6, the lower plate portion 203 may correspond to the metal portion 22 in Figure 6, and the lower plate portion 202 may correspond to the metal portion 23 in Figure 6. Similarly, the upper plate portion 104 may correspond to the metal portion 11 in Figure 6, the upper plate portion 106 may correspond to the metal portion 12 in Figure 6, and the upper plate portion 105 may correspond to the metal portion 13 in Figure 6. Furthermore, in the configuration shown in Figure 10(a), the lower plate portion 204 may correspond to the metal portion 21 in Figure 6, the lower plate portion 206 may correspond to the metal portion 22 in Figure 6, and the lower plate portion 205 may correspond to the metal portion 23 in Figure 6. Similarly, the upper plate portion 107 may correspond to the metal portion 11 in Figure 6, the upper plate portion 109 may correspond to the metal portion 12 in Figure 6, and the upper plate portion 108 may correspond to the metal portion 13 in Figure 6. Furthermore, in the configuration shown in Figure 10(a), the lower plate portion 207 may correspond to the metal portion 21 in Figure 6, the lower plate portion 209 may correspond to the metal portion 22 in Figure 6, and the lower plate portion 208 may correspond to the metal portion 23 in Figure 6. Similarly, the upper plate portion 110 may correspond to the metal portion 11 in Figure 6, the upper plate portion 112 may correspond to the metal portion 12 in Figure 6, and the upper plate portion 111 may correspond to the metal portion 13 in Figure 6. Also, in the configuration shown in Figure 10(a), the lower plate portion 210 may correspond to the metal portion 21 in Figure 6, the lower plate portion 212 may correspond to the metal portion 22 in Figure 6, and the lower plate portion 211 may correspond to the metal portion 23 in Figure 6.

[0104] The side section 4 shown in Figure 10(b) is composed of multiple side plate sections 401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, and 412 arranged along the planes Pc and Pd, as shown in Figures 11(a) and (b). The multiple side plate sections 401 to 412 are arranged within the planes Pc and Pd.

[0105] In each of the multiple side plate sections 401 to 412, two side plate sections connected to each other are connected by a connecting section 44 (not shown in the drawing). The number of connecting sections 44 can be M or M-1 (for example, M=12). For example, the metal part 51 is bent at the connecting section 44 between side plate section 401 and side plate section 402 of the multiple side plate sections 401 to 412. The metal part 51 is bent at the connecting section 44 between side plate section 402 and side plate section 403 of the multiple side plate sections 401 to 412. The metal part 51 is bent at the connecting section 44 between side plate section 403 and side plate section 404 of the multiple side plate sections 401 to 412. The metal part 51 is bent at the connecting section 44 between side plate section 411 and side plate section 412 of the multiple side plate sections 401 to 412. Of the multiple side plate sections 401 to 412, side plate section 412 and side plate section 401 may be joined by welding or the like at the joint between side plate section 412 and side plate section 401, or side plate section 412 and side plate section 401 may be separated.

[0106] Each of the multiple upper plate sections 101 to 112 is connected to a multiple side plate section 401 to 412 adjacent to any of the multiple upper plate sections 101 to 112 by a connecting section 41 (see Figure 10(b)). For example, at the connecting section 41 between upper plate section 101 of the multiple upper plate sections 101 to 112 and side plate section 401, the metal part 51 is bent by bending. At the connecting section 41 between upper plate section 102 of the multiple upper plate sections 101 to 112 and side plate section 402, the metal part 51 is bent by bending. At the connecting section 41 between upper plate section 103 of the multiple upper plate sections 101 to 112 and side plate section 403, the metal part 51 is bent by bending. At the connecting section 41 between upper plate section 104 of the multiple upper plate sections 101 to 112 and side plate section 404, the metal part 51 is bent by bending.

[0107] Each of the plurality of lower plate portions 201 to 212 is connected to a plurality of side plate portions 401 to 412 adjacent to any of the plurality of lower plate portions 201 to 212 at a connection portion 42 (see FIG. 10(b)). For example, at the connection portion 42 between the lower plate portion 201 and the side plate portion 401 among the plurality of lower plate portions 201 to 212, the metal part 51 is bent by bending. At the connection portion 42 between the lower plate portion 202 and the side plate portion 402 among the plurality of lower plate portions 201 to 212, the metal part 51 is bent by bending. At the connection portion 42 between the lower plate portion 203 and the side plate portion 403 among the plurality of lower plate portions 201 to 212, the metal part 51 is bent by bending. At the connection portion 42 between the lower plate portion 204 and the side plate portion 404 among the plurality of lower plate portions 201 to 212, the metal part 51 is bent by bending.

[0108] As described above, in the metal part 51, two portions connected to each other via the connection portions 41, 42, 43, 44 are bent at the connection portion therebetween. The angle formed by the two portions is defined by an obtuse angle of 0° to 180° or a convex angle of 180° to 360°. The bending angle of the two portions is defined by the angle obtained by subtracting the obtuse angle from 180°.

[0109] The obtuse angle formed by two connected side plate portions approximately coincides with the interior angle of a regular M-gon and is approximately (180 - (360 / M))°, and if M ≥ 5, it is an obtuse angle, if M = 5, it is 108°, and if M = 12, it is 150°. If M is replaced with m (M - 0.5 ≤ m < M + 0.5) when M = 12, the obtuse angle formed by two connected side plate portions is from 148.7° to 151.2°. The obtuse angle formed by the upper plate portions 101 to 112 and the side plate portions 401 to 412 connected to each other, and the obtuse angle formed by the lower plate portions 201 to 212 and the side plate portions 401 to 412 connected to each other are typically right angles (90°), but may be 80° to 100°.

[0110] Therefore, when M≧5, the inferior angle between two connected side plates is greater than the inferior angle between the connected upper plates 101~112 and side plates 401~412, and the inferior angle between the connected lower plates 201~212 and side plates 401~412. For example, the inferior angle between side plate 401 and side plate 402 is greater than the inferior angle between upper plate 101 and side plate 401, and the inferior angle between upper plate 102 and side plate 402. Also, the inferior angle between side plate 401 and side plate 402 is greater than the angle between lower plate 201 and side plate 401, and the angle between lower plate 202 and side plate 402. The inferior angle formed by the side plate portion 402 and the side plate portion 403 is greater than the inferior angle formed by the top plate portion 102 and the side plate portion 402, and the inferior angle formed by the top plate portion 103 and the side plate portion 403. Furthermore, the inferior angle formed by the side plate portion 402 and the side plate portion 403 is greater than the angle formed by the bottom plate portion 202 and the side plate portion 402, and the angle formed by the bottom plate portion 203 and the side plate portion 403.

[0111] As shown in Figure 11(a), eight elastic parts 31-38 are arranged in a plane Pc such that a virtual circle 318 passes through the eight elastic parts 31-38. As shown in Figure 11(b), eight elastic parts 31-38 are arranged in a plane Pd such that a virtual circle 328 passes through the eight elastic parts 31-38.

[0112] Figure 12(a) is a cross-sectional view of the sensor 10 shown in Figures 10 and 11, including the elastic parts 31 and 35.

[0113] The elastic portion 31 is provided below the upper plate portion 101 such that it overlaps with the upper plate portion 101 in the z direction. The elastic portion 31 is provided above the lower plate portion 201 such that it overlaps with the lower plate portion 201 in the z direction. The elastic portion 31 is provided between the upper plate portion 101 and the lower plate portion 201, which are opposite to each other.

[0114] The elastic portion 35 is provided below the upper plate portion 107 such that it overlaps with the upper plate portion 107 in the z direction. The elastic portion 32 is provided above the lower plate portion 207 such that the elastic portion 35 overlaps with the lower plate portion 207 in the z direction. The elastic portion 35 is provided between the upper plate portion 107 and the lower plate portion 207, which are opposite to each other.

[0115] In Figures 10 and 11, the elastic portion 32 is provided below the upper plate portion 103 so that it overlaps with the upper plate portion 103 in the z-direction. The elastic portion 32 is provided above the lower plate portion 203 so that it overlaps with the lower plate portion 203 in the z-direction. The elastic portion 32 is provided between the upper plate portion 103 and the lower plate portion 203, which are opposite to each other.

[0116] In Figures 10 and 11, the elastic portion 33 is provided below the upper plate portion 104 so that it overlaps with the upper plate portion 104 in the z-direction. The elastic portion 33 is provided above the lower plate portion 204 so that it overlaps with the lower plate portion 204 in the z-direction. The elastic portion 33 is provided between the upper plate portion 104 and the lower plate portion 204, which are opposite to each other.

[0117] Similarly, the elastic parts 34-38 overlap with the corresponding upper plate parts 106, 107, 109, 110, and 112, and overlap with the corresponding lower plate parts 206, 207, 209, 210, and 212.

[0118] As shown in Figure 12(a), each of the elastic parts 31-38 is joined to the upper surface 1 by a joint 46. This joint 46 may be, for example, a welded joint formed by welding adjacent elastic parts 31-38 to the upper surface 1, or it may be an adhesive joint that bonds adjacent elastic parts 31-38 to the upper surface 1. For example, overlapping elastic parts 31 and upper plate 101 are joined to each other by a joint 46 formed by welding. Overlapping elastic parts 35 and upper plate 107 are joined to each other by a joint 46 formed by welding. Similarly, elastic parts 32-34, 36-38 and the overlapping upper plate parts 103, 104, 106, 109, 110, 112 are also joined to each other by a joint 46.

[0119] As shown in Figure 12(a), each of the elastic parts 31-38 is joined to the lower surface part 2 by a joint 47. This joint 47 may be, for example, a welded joint formed by welding adjacent elastic parts 31-38 to the lower surface part 2, or it may be an adhesive joint that bonds adjacent elastic parts 31-38 to the lower surface part 2. For example, overlapping elastic parts 31 and lower plate part 201 are joined to each other by a joint 47 formed by welding. Overlapping elastic parts 35 and lower plate part 207 are joined to each other by a joint 47 formed by welding. Similarly, elastic parts 32-34, 36-38 and the overlapping lower plate parts 203, 204, 206, 209, 210, 212 are also joined to each other by a joint 47.

[0120] Figure 12(b) is a cross-sectional view of the sensor 10 shown in Figures 10(b), 11(a), and (b), including detectors 81 and 83. As shown in Figures 10(c) and 12(b), part 61 of detector 81 is fixed to the upper plate portion 102, and part 71 of detector 81 is fixed to the lower plate portion 202. Part 62 of detector 82 is fixed to the upper plate portion 105, and part 72 of detector 82 is fixed to the lower plate portion 205. Part 63 of detector 83 is fixed to the upper plate portion 108, and part 73 of detector 83 is fixed to the lower plate portion 208. Part 64 of detector 84 is fixed to the upper plate portion 111, and part 74 of detector 84 is fixed to the lower plate portion 211. Parts 61-64 are fixed to the structure 5 (e.g., upper surface portion 1) using, for example, adhesive. The parts 71-74 are also fixed to the structure 5 (for example, the lower part 2) using, for example, an adhesive.

[0121] As can be seen from Figures 10, 11, 12(a), and 12(b), the side portion 4 constitutes the outer surface of the metal part 51. Therefore, as shown in Figure 12(a), for example, the elastic portion 31 and the elastic portion 35 may be located between the side plate portion 401 and the side plate portion 407. Also, the distance between the elastic portion 31 and the elastic portion 35 is smaller than the distance between the side plate portion 401 and the side plate portion 407. Furthermore, as shown in Figure 12(c), for example, the detector 81 and the detector 83 may be located between the side plate portion 402 and the side plate portion 408.

[0122] In other embodiments, the side portion 4 may constitute the inner surface of the metal part 51. Therefore, as shown in Figure 12(c), for example, the side plate portion 401 and the side plate portion 407 may be located between the elastic portion 31 and the elastic portion 35. The distance between the elastic portion 31 and the elastic portion 35 may be greater than the distance between the side plate portion 401 and the side plate portion 407. Also, as shown in Figure 12(d), for example, the side plate portion 402 and the side plate portion 408 may be located between the detector 81 and the detector 83.

[0123] Here, a configuration has been described in which part 6 is fixed to the upper surface 1 and part 7 is fixed to the lower surface 2, so that part 6 and part 7 face each other in the z direction. However, it is sufficient for part 6 and part 7 to be displaced relative to each other due to the deformation of the structure 5, for example, so that part 6 and part 7 face each other in the r direction. In that case, for example, an inner surface and an outer surface can be provided, and one of part 6 and part 7 can be fixed to the inner surface and the other of part 6 and part 7 can be fixed to the outer surface. Alternatively, part 6 and part 7 can face each other in the θ direction. Furthermore, part 6 and 7 can be fixed to a part of the structure 5 other than the metal part having the elastic part group 3 (for example, a reinforcing part described later). Or, one of part 6 and 7 can be fixed to an external part of the sensor 10 (for example, a link described later) and the other of part 6 and 7 can be fixed to the sensor 10.

[0124] In the above-described configuration, the force to be detected was described as a force in the θ direction (circumferential direction). Therefore, the upper surface 1, lower surface 2, and side surface 4 of the structure 5 can function as rigid parts, relative to the elastic parts 31-38 of the structure 5. However, if the force to be detected is, for example, in the x, y, or r direction, the side surface 4 may function as an elastic part, and the parts described as elastic parts 31-38 may function as rigid parts. Furthermore, if the force to be detected is in the z direction, the parts described as elastic parts 31-38 and the side surface 4 may function as elastic parts.

[0125] As shown in Figure 10(c), holes 100 are provided in the upper surface portion 1 (upper plate portions 101-112). Holes 200 are also provided in the lower surface portion 2 (lower plate portions 201-212). These holes 100 and 200 are used to connect the metal part to other parts (for example, links or reinforcing parts described later) and the sensor 10. For example, screw grooves are formed on the inner surfaces of the holes 100 and 200, and screws that pass through the other parts are screwed into these holes 100 and 200 to fasten the other parts to the metal part 51. Alternatively, bolts that pass through the other parts pass through these holes 100 and 200 and are screwed into separately provided nuts, and the bolts and nuts fasten the other parts to the metal part 51.

[0126] The sensor structure 5 shown in Figure 13(b) may include a reinforcing part 56 shown in Figure 13(a) in addition to the metal part 51. The reinforcing part 56 overlaps with multiple elastic parts of the at least four elastic parts included in the elastic part group 3. The reinforcing part 56 is coupled to the metal part 51, and typically the reinforcing part 56 may be coupled to the upper surface 1 of the metal part 51. The sensor structure 5 may include a reinforcing part 57 shown in Figure 13(a) in addition to the metal part 51. The reinforcing part 57 overlaps with multiple elastic parts of the at least four elastic parts included in the elastic part group 3. The reinforcing part 57 is coupled to the metal part 51, and typically the reinforcing part 57 may be coupled to the lower surface 2 of the metal part 51. In this example, the reinforcing parts 56 and 57 have substantially the same shape as shown in Figure 13(a).

[0127] The metal part 51 is positioned between the reinforcing parts 56 and 57 and is connected to the reinforcing parts 56 and 57. The planar shape of the metal part 51 is approximately annular (regular M-gon), and the reinforcing parts 56 and 57 are also approximately annular, as shown in Figure 13(a). As shown in Figure 13(c), the annular reinforcing parts 56 and 57 are positioned so as to sandwich the annular metal part 51.

[0128] The metal part 51 of this embodiment has a structure in which the forms of the reinforcing parts 56 and 57 shown in Figure 6 are repeatedly arranged in a ring shape. In the form shown in Figure 13(b), of the reinforcing part 56, the part that overlaps with the upper plate part 101 (corresponding to the metal part 11) corresponds to the overlapping part 561, and the part that overlaps with the upper plate part 103 (corresponding to the metal part 12) may correspond to the overlapping part 562. The part that overlaps with the upper plate part 102 (corresponding to the metal part 13) may correspond to the intermediate part 563. Of the reinforcing part 57, the part that overlaps with the lower plate part 201 (corresponding to the metal part 21) corresponds to the overlapping part 571, and the part that overlaps with the lower plate part 203 (corresponding to the metal part 22) may correspond to the overlapping part 572. The part that overlaps with the lower plate part 202 (corresponding to the metal part 23) may correspond to the intermediate part 573. Furthermore, in the configuration shown in Figure 13(b), the portion of the reinforcing part 56 that overlaps with the upper plate portion 104 (corresponding to the metal portion 11) may correspond to the overlapping portion 561, and the portion that overlaps with the upper plate portion 106 (corresponding to the metal portion 12) may correspond to the overlapping portion 562. The portion that overlaps with the upper plate portion 105 (corresponding to the metal portion 13) may correspond to the intermediate portion 563. Of the reinforcing part 57, the portion that overlaps with the lower plate portion 204 (corresponding to the metal portion 21) may correspond to the overlapping portion 571, and the portion that overlaps with the lower plate portion 206 (corresponding to the metal portion 22) may correspond to the overlapping portion 572. The portion that overlaps with the lower plate portion 205 (corresponding to the metal portion 23) may correspond to the intermediate portion 573. Furthermore, in the configuration shown in Figure 13(b), the portion of the reinforcing part 56 that overlaps with the upper plate portion 107 (corresponding to the metal portion 11) may correspond to the overlapping portion 561, and the portion that overlaps with the upper plate portion 109 (corresponding to the metal portion 12) may correspond to the overlapping portion 562. The portion that overlaps with the upper plate portion 108 (corresponding to the metal portion 13) may correspond to the intermediate portion 563. Of the reinforcing part 57, the portion that overlaps with the lower plate portion 207 (corresponding to the metal portion 21) may correspond to the overlapping portion 571, and the portion that overlaps with the lower plate portion 209 (corresponding to the metal portion 22) may correspond to the overlapping portion 572. The portion that overlaps with the lower plate portion 208 (corresponding to the metal portion 23) may correspond to the intermediate portion 573. Furthermore, in the configuration shown in Figure 13(b), the portion of the reinforcing part 56 that overlaps with the upper plate portion 110 (corresponding to the metal portion 11) may correspond to the overlapping portion 561, and the portion that overlaps with the upper plate portion 112 (corresponding to the metal portion 12) may correspond to the overlapping portion 562. The portion that overlaps with the upper plate portion 111 (corresponding to the metal portion 13) may correspond to the intermediate portion 563.Among the reinforcing components 57, the portion overlapping with the lower plate portion 210 (corresponding to the metal portion 21) corresponds to the overlapping portion 571, and the portion overlapping with the lower plate portion 212 (corresponding to the metal portion 22) may correspond to the overlapping portion 572. The portion overlapping with the lower plate portion 211 (corresponding to the metal portion 23) may correspond to the relay portion 573. Also, among the reinforcing components 56, the portions overlapping with the upper plate portions 101, 103, 104, 106, 107, 110, 112 also serve as the extending portions 564, 565 (see FIG. 6). Among the reinforcing components 57, the portions overlapping with the lower plate portions 201, 203, 204, 206, 207, 210, 212 also serve as the extending portions 574, 575 (see FIG. 6).

[0129] FIG. 13(c) shows the thickness Ta of the upper surface portion 1, the thickness Tb of the lower surface portion 2, the height Hc of the side surface portion 4, and the height Hm of the metal component 51. Here, the height Hm is the sum of the thickness Ta, the thickness Tb, and the height Hc (Hm = Ta + Tb + Hc). The thickness Ta of the upper surface portion 1 and the thickness Tb of the lower surface portion 2 correspond to the thickness Tm of the metal member 50 (metal plate). Also, the thickness of the side surface portion 4 and the thicknesses of the elastic portions 31 to 38 also correspond to the thickness Tm of the metal member (sheet metal). Typically, the thickness Ta and the thickness Tb are smaller than the height Hc (Ta & Tb < Hc). Thus, by making the height Hc of the side surface portion 4 longer compared to the thicknesses Ta and Tb of the upper surface portion 1 and the lower surface portion 2, the rigidity of the metal component 51 with respect to the detection target force can be lowered. The thickness Ta and the thickness Tb are, for example, 0.4 to 3.2 mm, typically 1.0 to 2.5 mm. The height Hc is, for example, 5 to 20 mm, typically 10 to 15 mm. The height Hm is, for example, 6 to 26 mm, typically 12 to 19 mm.

[0130] FIG. 13(c) shows the thickness Sa of the reinforcing part 56 and the thickness Sb of the reinforcing part 57. The thickness Sa of the reinforcing part 56 is preferably greater than the thickness Ta of the upper surface part 1 (Sa > Ta). The thickness Sb of the reinforcing part 57 is preferably greater than the thickness Tb of the lower surface part 2 (Sb > Tb). Thus, by making the upper surface parts 1 and 2 thinner than the reinforcing parts 56 and 57, it is possible to improve the workability (ease of bending) of the metal part 51 while ensuring the rigidity of the structure 5 with the reinforcing parts 56 and 57. To achieve this, the thicknesses Sa and Sb of the reinforcing parts 56 and 57 may be made greater than the thickness Tm of the metal member 50 (Sa & Sb > Tm). The thickness Sa of the reinforcing part 56 and the thickness Sb of the reinforcing part 57 are preferably smaller than the height Hm of the metal part 51 (Sa & Sb < Hm). The thickness Sa of the reinforcing part 56 and the thickness Sb of the reinforcing part 57 are preferably smaller than the height Hc of the side surface part 4 (Sa & Sb < Hc). Thus, by making the height Hm of the metal part 51 and the height Hc of the side surface part 4 longer than the thicknesses Sa and Sb of the reinforcing parts 56 and 57, the rigidity of the metal part 51 with respect to the detection target force can be reduced. The height Hm of the metal part 51 generally corresponds to the distance between the reinforcing part 56 and the reinforcing part 57 at the portion sandwiching the elastic parts 31 to 38. Therefore, the thicknesses Sa and Sb of the reinforcing parts 56 and 57 may be smaller than the distance between the reinforcing part 56 and the reinforcing part 5). The thicknesses Sa and Sb are, for example, 1.0 to 5.0 mm, typically 1.5 to 3.0 mm. Summarizing the above, it can be said that it is preferable to satisfy the relationship of Ta & Tb & Tm < Sa & Sb < Hc < Hm.

[0131] The thickness Ta of the upper surface part 1 shown in FIG. 13(c) corresponds to the thicknesses T3, T5, and T6 in FIG. 6, and the thickness Tb of the lower surface part 2 corresponds to the thicknesses T4, T7, and T8 in FIG. 6. The thickness Sa of the reinforcing part 56 shown in FIG. 13(c) corresponds to the thicknesses S1, S2, S5, S7, and S8 in FIG. 6, and the thickness Sb of the reinforcing part 57 corresponds to the thicknesses S3, S4, S6, S9, and S10 in FIG. 6. The thickness Tm of each elastic part of the elastic part group 3 corresponds to the thicknesses T1 and T2 in FIG. 6.

[0132] The materials constituting the reinforcing parts 56 and 57 can be any material that can ensure the desired rigidity, and can be metal materials, ceramic materials, glass materials, plastic materials, etc., but metal materials with high toughness are preferred over ceramic materials and glass materials which have high brittleness. The metal material used for the reinforcing parts 56 and 57 is a single metal or a mixture (alloy) of metals. The reinforcing parts 56 and 57 may also be made of a base material made of metal material that has been plated. In order to ensure the rigidity of the structure 5, it is preferable that the reinforcing parts 56 and 57 are hard, and for example, it is preferable that they be made of a metal material with a Vickers hardness of 90 HV or higher. The material for the reinforcing parts 56 and 57 can be iron alloys (steel) such as carbon steel and alloy steel, aluminum alloys, titanium alloys, etc., but in terms of material cost, iron alloys are preferred. As the metal material for the reinforcing parts 56 and 57, alloy steel, in particular stainless steel (SUS), is preferred. For example, magnetic stainless steel can be used for the reinforcing parts 56 and 57. Since the reinforcing parts 56 and 57 have a simpler structure than the metal part 51 which has elastic parts 31 to 38, the reinforcing parts 56 and 57 can be manufactured inexpensively by methods such as machining or casting.

[0133] If the metal part 51 has eight elastic parts 31 to 38, the reinforcing parts 56 and 57 may overlap the eight elastic parts 31 to 38. The reinforcing parts 56 and 57 do not need to overlap all of the elastic parts included in the group of elastic parts 3, and the elastic parts that the reinforcing part 56 overlaps and the elastic parts that the reinforcing part 57 overlaps do not need to be perfectly coincident.

[0134] The reinforcing part 56 and the upper part 1 are joined at a joint 58 shown in Figure 13(b). This joint 58 may be, for example, a welded joint where the upper plate part 1 and the reinforcing part 56 are welded together, or it may be, for example, an adhesive joint where the upper part 1 and the reinforcing part 56 are bonded together. The reinforcing part 57 and the lower part 2 are joined at a joint 59 (not shown) in the same manner as the joint 58. This joint 59 may be, for example, a welded joint where the lower plate part 2 and the reinforcing part 57 are welded together, or it may be, for example, an adhesive joint where the lower plate part 2 and the reinforcing part 57 are bonded together.

[0135] The joint 58 connects the upper plate sections 101, 103, 104, 106, 107, 109, 110, and 112, which overlap the elastic sections 31-38, with the reinforcing part 56. As mentioned above, the elastic sections 31-38 are connected to the upper plate sections 101, 103, 104, 106, 107, 109, 110, and 112 at the joint 46. Therefore, it can be said that the reinforcing part 56 is connected to the elastic sections 31-38 via the upper plate sections 101, 103, 104, 106, 107, 109, 110, and 112 by the joints 46 and 58. In addition, the joint 58 connects the upper plate sections 102, 105, 108, and 111, to which parts 61-64 are fixed, with the reinforcing part 56. Therefore, it can be said that the reinforcing part 56 is connected to parts 61-64 via the upper plate parts 102, 105, 108, and 111 by the joint part 58.

[0136] Similarly, joint 59 connects the lower plate portions 201, 203, 204, 206, 207, 209, 210, and 212, which overlap the elastic portions 31-38, with the reinforcing part 57. As mentioned above, the elastic portions 31-38 are connected to the lower plate portions 201, 203, 204, 206, 207, 209, 210, and 212 at joint 47. Therefore, it can be said that the reinforcing part 57 is connected to the elastic portions 31-38 via the lower plate portions 201, 203, 204, 206, 207, 209, 210, and 212 by joints 47 and 59. In addition, joint 59 connects the lower plate portions 202, 205, 208, and 211, to which parts 71-74 are fixed, with the reinforcing part 57. Therefore, it can be said that the reinforcing part 57 is connected to parts 71-74 via the lower plate parts 202, 205, 208, and 211 by the joint part 59. In this way, the connection of the reinforcing parts 56 and 57 to the elastic parts 31-38 or detectors 81-84 improves the detection accuracy of the sensor 10.

[0137] At least one of the components 61-64 and 71-74 of the detectors 81-84 may be fixed to the reinforcing components 56 and 57. In this case, at least one of the components 61-64 and 71-74 may be directly bonded to the reinforcing components 56 and 57, or directly bonded to a support component fixed to the reinforcing components 56 and 57.

[0138] As shown in Figure 13(a), the reinforcing part 56 is provided with a hole 560, and the reinforcing part 57 is provided with a hole 570. These holes 560 and 570 are used to connect the structure 5 to other parts (for example, a link or metal part 51 described later) and the sensor 10. For example, screw grooves are formed on the inner surfaces of the holes 560 and 570, and screws that pass through the other parts are screwed into these holes 560 and 570 to fasten the other parts to the reinforcing parts. In this case, the portion of the screw that is screwed into the holes 560 and 570 that protrudes from the reinforcing parts 56 and 57 (holes 560 and 570) may be housed in the holes 100 and 200 of the metal part 51. Alternatively, a bolt that passes through the other parts may pass through these holes 560 and 570 and be screwed into a separately provided nut, thereby fastening the other parts to the reinforcing parts 56 and 57 with the bolt and nut. Alternatively, screws that pass through other parts may pass through these holes 560 and 570 and be screwed into holes 100 and 200 in the metal part 51, and fastened to the reinforcing parts 56 and 57 with screws. The hole 560 in the reinforcing part 56 and the hole 100 in the upper part 1 overlap each other, and screws or bolts may be inserted into both. The hole 570 in the reinforcing part 57 and the hole 200 in the lower part 2 overlap each other, and screws or bolts may be inserted into both.

[0139] For example, an electro-galvanized steel sheet (SECC) with a thickness Tm of 1.6 mm is punched and bent to create a metal part 51 with an inner diameter of 78 mm, an outer diameter of 106 mm, a thickness Hm of 15.6 mm, and a height Hc of 12.4 mm. The thickness of the top, bottom, and side surfaces is 1.6 mm. The inner diameter of reinforcing parts 56 and 57 is 78 mm, the outer diameter is 106 mm, and the thicknesses Sa and Sb are 2.3 mm. The elastic constants of metal part 51 and reinforcing parts 56 and 57 are Young's modulus: 195 [GPa] and Poisson's ratio: 0.29. Under these conditions, using the finite element method, the stiffness Gb against the bending moment in the other axis was found to be Gb = 169 [kNm / rad] for the configuration in Figure 10(c) and Gb = 591 [kNm / rad] for the configuration in Figure 13(b). Thus, it can be seen that the addition of reinforcing parts 56 and 57 increases the rigidity by approximately 3.5 times, and significantly reduces the effects of cross-axial interference. The physical properties of reinforcing parts 56 and 57 are as follows: the specific electrical resistivity is 75 μΩ·cm to 85 μΩ·cm at room temperature, and the thermal conductivity is 0.0340 cal / cm·sec·℃ to 0.0540 cal / cm·sec·℃ at 100℃. The coefficient of thermal expansion of reinforcing parts 56 and 57 is 9.8 × 10⁻⁶. -6 / ℃ or higher 11.8×10 -6 Below / ℃, the elastic modulus is 10.0 × 10 3 kg / mm 2 The above 30.0 x 10 3 kg / mm 2 The following are included, and they contain copper and niobium.

[0140] Using Figure 14, another embodiment in which the structure 5 includes reinforcing parts 56 and 57 will be described.

[0141] Figure 14(a) is a plan view taken from the Z direction, showing the overlap between the metal part 51 and the reinforcing parts 56 and 57. The reinforcing parts 56 and 57 shown in Figure 14(a) are disc-shaped. These disc-shaped reinforcing parts 56 and 57 overlap with the eight elastic parts 31 to 38. Making the reinforcing parts 56 and 57 disc-shaped improves the rigidity of the reinforcing parts 56 and 57 compared to making them annular, and also improves the rigidity of the structure 5. The reinforcing parts 56 and 57 overlap with each other in parts that do not overlap with the metal part 51 (the parts that sandwich the part enclosed by the metal part 51).

[0142] Figure 14(b) shows a configuration in which the reinforcing part 56 shown in Figure 13(a) is divided into multiple reinforcing parts 56a and 56b, and the reinforcing part 57 shown in Figure 13(a) is divided into multiple reinforcing parts 57a and 57b. The sensor 10 structure 5 is provided with four reinforcing parts: two reinforcing parts 56a and 56b connected to the upper surface 1 of the metal part 51, and two reinforcing parts 57a and 57b connected to the lower surface 2 of the metal part 51. The reinforcing parts 56a and 57a overlap with four of the eight elastic parts 31 to 33 and 38. Four elastic parts 31 to 33 and 38 are provided between the reinforcing part 56a and the reinforcing part 57a. The reinforcing parts 56b and 57b overlap with four of the eight elastic parts 31 to 38, 34 to 37. Four elastic parts 34-37 are provided between reinforcing part 56b and reinforcing part 57b.

[0143] Figures 14(c) and (d) show configurations using cross-shaped reinforcing parts 56 and 57. Reinforcing part 56 overlaps with elastic parts 31, 33, 35, and 37, but does not overlap with elastic parts 32, 34, 36, and 38. Reinforcing part 57 overlaps with elastic parts 32, 34, 36, and 38, but does not overlap with elastic parts 31, 33, 35, and 37. Reinforcing parts 56 and 57 overlap with each other in portions that do not overlap with metal part 51.

[0144] In Figure 14(c), the portion of the reinforcing part 56 that overlaps with the elastic part 31 (corresponding to the overlapping part 561) and the portion that overlaps with the elastic part 35 (corresponding to the overlapping part 562) in the r direction (radial direction) corresponds to the intermediate part 563. Also, the portion of the reinforcing part 56 that overlaps with the elastic part 33 (corresponding to the overlapping part 561) and the portion that overlaps with the elastic part 37 (corresponding to the overlapping part 562) in the r direction (radial direction) corresponds to the intermediate part 563. In Figure 14(d), the portion of the reinforcing part 57 that overlaps with the elastic part 32 (corresponding to the overlapping part 571) and the portion that overlaps with the elastic part 36 (corresponding to the overlapping part 572) in the r direction (radial direction) corresponds to the intermediate part 573. Furthermore, of the reinforcing part 57, the portion that overlaps with the elastic part 34 (corresponding to the overlapping part 571) and the portion that overlaps with the elastic part 38 (corresponding to the overlapping part 572) are connected in the r direction (radial direction), and this portion corresponds to the intermediate part 573. The portion of the reinforcing part 56 that corresponds to the intermediate part 563 and the portion of the reinforcing part 57 that corresponds to the intermediate part 573 overlap each other in the z direction, and there is no metal part 51 located between them.

[0145] The contours of the reinforcing parts 56 and 57 may be approximately the same as, or different from, the contour 55 of the metal part 51. In this example, the contour 55 of the metal part 51 is a roughly regular dodecagon, and the contours of the reinforcing parts 56 and 57 are circular. The reinforcing parts 56 and 57 may be provided with extended portions that extend outward from the contour 55 of the metal part 51, for example, the parts 6 and 7 of the detection means 8 may be fixed to the extended portions of the reinforcing parts 56 and 57.

[0146] The molding method for the metal part 51 shown in Figures 10 to 12 will be explained using Figures 15, 16, 17, and 18. This example is merely one example that is considered to be industrially feasible and is not limited to this method.

[0147] First, a metal member 50 is prepared as shown in Figure 15(a). At this stage, the metal member 50 is a long, narrow plate-shaped member (metal sheet) with a thickness Tm. The thickness Tm can be, for example, 0.4 to 3.2 mm. The metal member 50 can be manufactured by punching out the desired shape as shown in Figure 15(a) from the metal sheet material. Furthermore, since the metal material of the metal part 51 is required to be easy to bend, ordinary steel (carbon steel with a carbon content of 0.6% or less) is preferable. The metal member that will become the metal part 51 can be, for example, cold-rolled steel sheet (SPCC) or electro-galvanized steel sheet (SECC, Bonderized steel sheet) which is cold-rolled steel sheet electro-galvanized.

[0148] The metal member 50 has an upper portion which becomes the upper surface portion 1, a lower portion which becomes the lower surface portion 2, and a central portion located between the upper and lower portions which becomes the elastic portion 3 and the side portion 4. The upper portion is provided with upper plate portions 101 to 112. The lower portion is provided with portions which become the lower plate portions 201 to 212. The central portion is provided with portions which become the elastic portions 31 to 38 and portions which become the side plate portions 401 to 412. At this stage, the metal member 50 is formed, for example, by shearing sheet metal. The metal member 50 at this stage may be formed by cutting from a square bar or by casting, but forming by shearing is advantageous in terms of cost.

[0149] Next, the metal member 50 shown in Figure 15(a) is subjected to the first to third bending processes to form the metal member 50 into the shape shown in Figure 15(b). At this stage, the metal member 50 is a long, slender U-shaped member. The upper and lower portions face each other. Also, the elastic portions 31 to 38 overlap the upper and lower portions. In this example, there are M connection parts 44 between the side plate portions 401 to 412, with the side plate portion 401 and a part of the side plate portion 412 being connected via the connection parts, and the side plate portion 411 and the remaining part of the side plate portion 412 being connected via the connection parts.

[0150] Figure 16(a) shows a magnified portion of the metal member 50 for illustrative purposes. Figure 16(a) shows the state of the metal member 50 before the first to third bending processes are performed, Figure 16(c) shows the state of the metal member 50 after the first to third bending processes are performed, and Figure 16(b) shows the state of the metal member 50 before and after the first to third bending processes are performed.

[0151] Using the R-shaped section 917, indicated by the dashed line in Figure 16(a), as the bending line, a first bending process is performed as shown in Figure 16(b) so that the elastic sections 31-38 bend by 80°-100° (90° in this example) in the direction of the arrow 918.

[0152] Using the R-shaped section 912, indicated by the dashed line in Figure 16(a), as the bending line, a second bending process is performed as shown in Figure 16(b) so that the lower plate sections 201-212 bend by 80°-100° (90° in this example) in the direction of the arrow 913.

[0153] Using the R-shaped section 914, indicated by the dashed line in Figure 16(a), as the bending line, a third bending process is performed as shown in Figure 16(b) so that the upper plate sections 101-112 bend by 80°-100° (90° in this example) in the direction of the arrow 915.

[0154] As shown in Figure 16(c), the elastic portions 31-38 overlap the upper plate portions 101-112 and the lower plate portions 201-212.

[0155] The order of the first to third bending processes is arbitrary, but it is preferable to perform the second and third bending processes after the first bending process. This is because if the second and third bending processes are performed before the first bending process, the upper plate sections 101-112 and the lower plate sections 201-212 tend to interfere with the first bending process.

[0156] Next, the metal member 50 shown in Figure 15(b) is subjected to a fourth bending process to form the metal member 50 into the shape shown in Figure 17(a). Furthermore, the metal member 50 shown in Figure 17(a) is subjected to a fourth bending process to form the metal member 50 into the shape shown in Figure 17(b).

[0157] Figure 18(a) shows a magnified portion of the metal member 50 for illustrative purposes. Figure 18(a) shows the state of the metal member 50 before the fourth bending process is performed, Figure 18(c) shows the state of the metal member 50 after the fourth bending process is performed, and Figure 18(b) shows the state of the metal member 50 before and after the fourth bending process is performed.

[0158] In Figure 18(a), the R-shaped section 920, indicated by the dashed line, is used as the bending line, and a fourth bending process is performed as shown in Figure 18(b) so that the side sections 401-412 bend by 30° ((360 / M)°) in the direction of the arrow 922. Due to the fourth bending process, two adjacent upper plate sections (for example, upper plate section 101 and upper plate section 102) among the upper plate sections 101-112 may come into contact. In order to minimize the gap between two adjacent upper plate sections, the angle between the opposing surfaces of two adjacent upper plate sections (for example, upper plate section 101 and upper plate section 102) among the upper plate sections 101-112 is set to ((360 / M)°) before the fourth bending process. A part of the side plate section 412 connected to the side plate section 401 and the remaining part of the side plate section 412 connected to the side plate section 411 are connected.

[0159] As shown in Figures 18(a) and (c), the connection portion 43 between the connected side plate portions and elastic portions (for example, side plate portion 401 and elastic portion 31, side plate portion 403 and elastic portion 32) includes an upper portion 431 and a lower portion 432 aligned in the z direction, with a gap 430 provided between the upper portion 431 and the lower portion 432. The gap 430 can function as a relief hole in the third bending process. Furthermore, by providing the gap 430, the rigidity of the connection portion 43 is reduced, thereby reducing the rigidity of the elastic portion group 3 and making the structure 5 more easily deformable.

[0160] As shown in Figures 18(a) and (c), the connection portion 44 between two adjacent side plate portions (for example, side plate portion 401 and side plate portion 402) includes an upper portion 441 and a lower portion 442 aligned in the z direction, with a gap 440 provided between the upper portion 441 and the lower portion 442. The gap 440 can function as a relief hole in the third bending process. Furthermore, by providing the gap 440, the rigidity of the connection portion 44 is reduced, thereby reducing the rigidity of the side portion 4 and making the structure 5 more easily deformable.

[0161] Next, in Figure 17(b), joints 46 are formed between the upper plate portions 101, 103, 104, 106, 107, 109, 110, and 112 and the overlapping upper plate portions and elastic portions from elastic portions 31 to 38. Also, joints 47 are formed between the lower plate portions 201, 203, 204, 206, 207, 209, 210, and 212 and the overlapping lower plate portions and elastic portions from elastic portions 31 to 38. Joints 48 are formed between adjacent upper plate portions 101 to 112. Also, joints 49 are formed between adjacent lower plate portions 201 to 212. Arc welding, spot welding, or laser welding can be used to form the joints 46 to 49.

[0162] As described above, by bending a metal member 50 having multiple elastic parts 31 to 38, a metal part 51 having multiple elastic parts 31 to 38 can be formed.

[0163] A modified example of the metal part 51 will be explained using Figure 19. Figure 19(a) is a perspective view of the metal part 51, and Figure 19(b) is a cross-sectional view of the metal part 51 including the elastic parts 31 and 35, along the thick line shown in Figure 19(a).

[0164] In the metal part 51 shown in Figures 10 to 13, the metal part 51 was bent at the connection between the side portion 4 and the elastic portion group 3. However, in this embodiment, each of the elastic portions 31 to 38 of the elastic portion group 3 is connected to the upper surface portion 1. The metal part 51 is bent by bending at the connection between each of the elastic portions 31 to 38 of the elastic portion group 3 and the upper surface portion 1. For example, the metal part 51 is bent by bending at the connection between the upper plate portion 101 and the elastic portion 31. The elastic portion 31 is provided on the lower plate portion 201 so that the elastic portion 31 overlaps the lower plate portion 201 in the z direction. Also, the metal part 51 is bent by bending at the connection between the upper plate portion 103 and the elastic portion 32. The elastic portion 32 is provided on the lower plate portion 203 so that the elastic portion 32 overlaps the lower plate portion 203 in the z direction. At the connection between the upper plate portion 107 and the elastic portion 35, the metal part 51 is bent by bending. The elastic portion 33 is provided on the lower plate portion 207 such that the elastic portion 35 overlaps the lower plate portion 207 in the z direction. Similarly, the elastic portions 33, 34, 36, 37, and 38 overlap the corresponding lower plate portions 206, 207, 209, 210, and 212.

[0165] As shown in Figure 19(b), each of the elastic parts 31-38 is joined to the lower surface part 2 by a joint 47. This joint 47 may be, for example, a welded joint formed by welding adjacent elastic parts 31-38 to the lower surface part 2, or it may be an adhesive joint that bonds adjacent elastic parts 31-38 to the lower surface part 2. For example, overlapping elastic parts 31 and lower plate part 201 are joined to each other by a joint 47 formed by welding. Overlapping elastic parts 35 and lower plate part 207 are joined to each other by a joint 47 formed by welding. Similarly, elastic parts 32-34, 36-38 and the overlapping lower plate parts 203, 204, 206, 209, 210, 212 are also joined to each other by a joint 47.

[0166] As can be seen from Figures 19(a) and (b), the side portion 4 constitutes the outer surface of the metal part 51. Therefore, as shown in Figure 19(b), for example, the distance between the elastic portion 31 and the elastic portion 35 is smaller than the distance between the side plate portion 401 and the side plate portion 407. In other embodiments, the side portion 4 may constitute the inner surface of the metal part 51. Therefore, as shown in Figure 19(c), for example, the distance between the elastic portion 31 and the elastic portion 35 may be larger than the distance between the side plate portion 401 and the side plate portion 407.

[0167] <Fourth Embodiment> In the fourth embodiment, similar to the second embodiment, the elastic group 3 of the structure 5 is composed of multiple metal parts. Figure 20(a) shows an example in which the elastic group 3 of the structure 5 is divided into two metal parts 51 and 52. The semi-circular metal part 51 has four elastic parts 31 to 34, and the semi-circular metal part 52 has four elastic parts 35 to 38. The metal part 51 has upper plate parts 101 to 106, lower plate parts 201 to 206, and side plate parts 401 to 406, and the metal part 52 has upper plate parts 107 to 112, lower plate parts 207 to 212, and side plate parts 407 to 412. Detectors 81 and 82 are fixed to the metal part 51, and detectors 83 and 84 are fixed to the metal part 52. Metal parts 51 and 52 are arranged such that the eight elastic parts 31-38, upper plate parts 101-112, lower surface parts 201-212, side parts 401-412, and detectors 81-84 are arranged in the same way as the structure 5 in Figures 19 and 20.

[0168] Figure 20(b) shows an example in which the elastic group 3 of the structure 5 is divided into four metal parts 51, 52, 53, and 54. The quarter-ring metal part 51 has two elastic parts 31 and 32, and the semi-ring metal part 52 has two elastic parts 33 and 34. The quarter-ring metal part 53 has two elastic parts 35 and 36, and the semi-ring metal part 54 has two elastic parts 37 and 38. Metal part 51 has upper plate parts 101 to 103, lower plate parts 201 to 203, and side plate parts 401 to 403, and metal part 52 has upper plate parts 104 to 106, lower plate parts 204 to 206, and side plate parts 404 to 406. Metal part 53 has upper plate portions 107-109, lower plate portions 207-209, and side plate portions 407-409, and metal part 54 has upper plate portions 110-112, lower plate portions 210-212, and side plate portions 410-412. Detector 81 is fixed to metal part 51, detector 82 is fixed to metal part 52, detector 83 is fixed to metal part 53, and detector 84 is fixed to metal part 54.

[0169] The metal parts 51-54 are arranged such that the eight elastic parts 31-38, upper plate parts 101-112, lower surface parts 201-212, side parts 401-412, and detectors 81-84 are arranged in the same manner as the structure 5 in Figures 19 and 20.

[0170] When structure 5 is composed of multiple metal parts, each having at least two elastic parts, the precision of structure 5 can be improved by selecting each of the multiple metal parts from metal parts that provide sufficient performance. The more elastic parts a single metal part has, the lower the yield of that single metal part may become. Therefore, by reducing the number of elastic parts in a single metal part and increasing the number of metal parts, the yield of structure 5 can be improved while maintaining the same number of elastic parts. In the example shown in Figure 20(a), structure 5 is divided into two parts, and in the example shown in Figure 20(b), structure 5 is divided into four parts, but structure 5 may also be divided into three or six parts. However, if the number of divisions of structure 5 (number of metal parts with elastic parts) is large, the assembly of structure 5 tends to become complicated, so it is preferable that structure 5 be divided into about four parts.

[0171] The multiple metal parts that make up structure 5 can be manufactured by bending each of separate metal members, or by bending a single metal member and then cutting it to produce multiple metal parts.

[0172] When the structure 5 is composed of multiple metal parts, each having at least two elastic parts, it is preferable that four or more elastic parts, which are distributed among these multiple metal parts, deform similarly. For this reason, it is preferable that the multiple metal parts are connected by reinforcing parts. In the embodiment shown in Figure 20(c), the metal parts 51 and 52 shown in Figure 20(a) or Figure 20(b) are connected via reinforcing part 56. The reinforcing part 56 is joined to the upper surface of the metal part 51 and to the upper surface of the metal part 52. The reinforcing part 56 overlaps with the elastic parts of the metal part 51 and the elastic parts of the metal part 52, respectively. In addition, the metal parts 51 and 52 are connected via reinforcing part 57. The reinforcing part 57 is joined to the lower surface of the metal part 51 and to the lower surface of the metal part 52. The reinforcing part 57 overlaps with the elastic parts of the metal part 51 and the elastic parts of the metal part 52, respectively. The configuration shown in Figure 14(b) and the configuration shown in Figure 20(b) can be combined. For example, reinforcing part 56a may connect metal part 51 and metal part 52, and reinforcing part 56b may connect metal part 53 and metal part 54. However, this alone would leave metal part 51 and metal part 54 unconnected, and metal part 52 and metal part 53 unconnected. Therefore, reinforcing part 57a may further connect metal part 51 and metal part 54, and reinforcing part 57b may connect metal part 52 and metal part 53. This allows for a configuration in which the four metal parts 51-54 are interconnected by the four reinforcing parts 56a, 56b, 57a, and 57b.

[0173] The configuration shown in Figure 20(b) will be explained in more detail using Figure 21. The metal parts 51 to 54 shown in Figure 20(b) are each formed by bending the metal member 50 shown in Figure 21(a).

[0174] In the process shown in Figure 21(a), a metal member 50 is prepared. The metal member 50 has side plate portions 451, 452, and 453, upper plate portions 151, 152, and 153 connected to the side plate portions 451, 452, and 453, lower plate portions 251, 252, and 253 connected to the side plate portions 451, 452, and 453, and elastic portions 351 and 352 connected to the side plate portions 451 and 453.

[0175] In the process shown in Figure 21(b), a first bending process is performed on the upper plate sections 151-153 in the direction of arrow 915 so that the metal member 50 bends at the connection point between the side plate sections 451-453 and the upper plate sections 151-153. A second bending process is performed on the lower plate sections 251-253 in the direction of arrow 913 so that the metal member 50 bends at the connection point between the side plate sections 451-453 and the lower plate sections 251-253. The bending angles for the first and second bending processes are 80° to 100° (90° in this example).

[0176] In the process shown in Figure 21(c), a third bending process is performed on the elastic parts 351 and 352 in the direction of arrow 918 so that the metal member 50 bends at the connection point between the side plate parts 451 and 453 and the elastic parts 351 and 352. The bending angle of the third bending process is 80° to 100° (90° in this example).

[0177] In the process shown in Figure 21(d), a fourth bending process is performed on the side plates 451 and 452 in the direction of arrow 922 so that the metal member 50 bends at the connection between the side plate 451 and the side plate 452, and at the connection between the side plate 452 and the side plate 453. The bending angle of the fourth bending process is 20° to 40° (30° in this example).

[0178] In the process shown in Figure 21(e), each part of the metal member 50 is welded to each other. The upper plate portion 151 and the elastic portion 351 are joined at the joint portion 46, and the upper plate portion 153 and the elastic portion 353 are joined at the joint portion 46. The lower plate portion 251 and the elastic portion 352 are joined at the joint portion 47, and the lower plate portion 253 and the elastic portion 352 are joined at the joint portion 47. The upper plate portion 151 and the upper plate portion 152 are joined at the joint portion 48, and the upper plate portion 152 and the upper plate portion 153 are joined at the joint portion 48. The lower plate portion 251 and the lower plate portion 252 are joined at the joint portion 49, and the lower plate portion 252 and the lower plate portion 253 are joined at the joint portion 49.

[0179] In this way, four metal parts 51 to 54 are manufactured, each having elastic parts 351 and 352.

[0180] In the process shown in Figure 21(f), in addition to the four metal parts 51 to 54, reinforcing parts 56 and 57 are prepared. Reinforcing part 56 is provided with various fixing holes 560 and 506, and reinforcing part 57 is provided with various fixing holes 570 and 507. The four metal parts 51 to 54 are sandwiched between reinforcing parts 56 and 57. The metal parts 51 to 54 are arranged such that a virtual circle passes through their respective elastic parts 351 and 352. The elastic part 351 of metal part 51 corresponds to the elastic part 31 in Figures 10 to 14, and the elastic part 352 of metal part 51 corresponds to the elastic part 32 in Figures 10 to 14. The elastic part 351 of metal part 52 corresponds to the elastic part 33 in Figures 10 to 14, and the elastic part 352 of metal part 52 corresponds to the elastic part 34 in Figures 10 to 14. The elastic portion 351 of metal part 53 corresponds to the elastic portion 35 in Figures 10-14, and the elastic portion 352 of metal part 53 corresponds to the elastic portion 36 in Figures 10-14. The elastic portion 351 of metal part 54 corresponds to the elastic portion 37 in Figures 10-14, and the elastic portion 352 of metal part 54 corresponds to the elastic portion 38 in Figures 10-14.

[0181] The upper plate portion 151 of metal part 51 corresponds to the upper plate portion 101 in Figures 10-14, the upper plate portion 152 of metal part 51 corresponds to the upper plate portion 102 in Figures 10-14, and the upper plate portion 153 of metal part 51 corresponds to the upper plate portion 103 in Figures 10-14. The upper plate portion 151 of metal part 52 corresponds to the upper plate portion 104 in Figures 10-14, the upper plate portion 152 of metal part 52 corresponds to the upper plate portion 105 in Figures 10-14, and the upper plate portion 153 of metal part 52 corresponds to the upper plate portion 106 in Figures 10-14. The upper plate portion 151 of metal part 53 corresponds to the upper plate portion 107 in Figures 10-14, the upper plate portion 152 of metal part 53 corresponds to the upper plate portion 108 in Figures 10-14, and the upper plate portion 153 of metal part 53 corresponds to the upper plate portion 109 in Figures 10-14. The upper plate portion 151 of metal part 54 corresponds to the upper plate portion 110 in Figures 10-14, the upper plate portion 152 of metal part 54 corresponds to the upper plate portion 111 in Figures 10-14, and the upper plate portion 153 of metal part 54 corresponds to the upper plate portion 112 in Figures 10-14.

[0182] The lower plate portion 251 of metal part 51 corresponds to the lower plate portion 201 in Figures 10-14, the lower plate portion 252 of metal part 51 corresponds to the lower plate portion 202 in Figures 10-14, and the lower plate portion 253 of metal part 51 corresponds to the lower plate portion 203 in Figures 10-14. The lower plate portion 251 of metal part 52 corresponds to the lower plate portion 204 in Figures 10-14, the lower plate portion 252 of metal part 52 corresponds to the lower plate portion 205 in Figures 10-14, and the lower plate portion 253 of metal part 52 corresponds to the lower plate portion 206 in Figures 10-14. The lower plate portion 251 of metal part 53 corresponds to the lower plate portion 207 in Figures 10-14, the lower plate portion 252 of metal part 53 corresponds to the lower plate portion 208 in Figures 10-14, and the lower plate portion 253 of metal part 53 corresponds to the lower plate portion 209 in Figures 10-14. The lower plate portion 251 of metal part 54 corresponds to the lower plate portion 210 in Figures 10-14, the lower plate portion 252 of metal part 54 corresponds to the lower plate portion 211 in Figures 10-14, and the lower plate portion 253 of metal part 54 corresponds to the lower plate portion 212 in Figures 10-14.

[0183] The side plate portion 451 of metal part 51 corresponds to the side plate portion 401 in Figures 10-14, the side plate portion 452 of metal part 51 corresponds to the side plate portion 402 in Figures 10-14, and the side plate portion 453 of metal part 51 corresponds to the side plate portion 403 in Figures 10-14. The side plate portion 451 of metal part 52 corresponds to the side plate portion 404 in Figures 10-14, the side plate portion 452 of metal part 52 corresponds to the side plate portion 405 in Figures 10-14, and the side plate portion 453 of metal part 52 corresponds to the side plate portion 406 in Figures 10-14. The side plate portion 451 of metal part 53 corresponds to the side plate portion 407 in Figures 10-14, the side plate portion 452 of metal part 53 corresponds to the side plate portion 408 in Figures 10-14, and the side plate portion 453 of metal part 53 corresponds to the side plate portion 409 in Figures 10-14. The side plate portion 451 of metal part 54 corresponds to the side plate portion 410 in Figures 10-14, the side plate portion 452 of metal part 54 corresponds to the side plate portion 411 in Figures 10-14, and the side plate portion 453 of metal part 54 corresponds to the side plate portion 412 in Figures 10-14.

[0184] In the process shown in Figure 21(g), the reinforcing part 56 is joined to the upper plate portions 151 to 53 of the metal members 51 to 54 at the joint 58, and the reinforcing part 57 is joined to the lower plate portions 251 to 252 of the metal members 51 to 54 at the joint 59.

[0185] In the process shown in Figure 21(h), a head unit 60, which includes component 6, the detection head of the encoder, and a scale unit 70, which includes component 7, the scale of the encoder, are fixed to the structure 5. The head unit 60 includes component 6 and a retaining component 66 that holds component 6. The retaining component 66, holding component 6, is fixed to the reinforcing component 56 with fixing components 65 such as screws, rivets, or bolts. The fixing component 65 that fixes the retaining component 66 is inserted into a hole 506 and connects to the retaining component 66. The scale unit 70 includes component 7 and a retaining component 77 that holds component 7. The retaining component 77, holding component 7, is fixed to the reinforcing component 57 with fixing components 75 such as screws, rivets, or bolts. The fixing component 75 that fixes the retaining component 77 is inserted into a hole 507 and connects to the retaining component 77.

[0186] The retaining part 66 has a fixing part 67 that is fixed to the reinforcing part 56 and a retaining part 68 that holds the part 6, and the retaining part 66 is bent by bending at the connection part 69 between the fixing part 67 and the retaining part 68. The retaining part 77 has a fixing part 76 that is fixed to the reinforcing part 57 and a retaining part 78 that holds the part 7, and the retaining part 77 is bent by bending at the connection part 79 between the fixing part 76 and the retaining part 78.

[0187] In detector 81, the fixing portion 67 of the holding component 66 is provided between the upper plate portion 153 (equivalent to upper plate portion 103) of metal component 51 and the upper plate portion 151 (equivalent to upper plate portion 104) of metal component 52. In detector 81, the fixing portion 76 of the holding component 77 is provided between the lower plate portion 253 (equivalent to lower plate portion 203) of metal component 51 and the lower plate portion 251 (equivalent to lower plate portion 204) of metal component 52. In detector 82, the fixing portion 67 of the holding component 66 is provided between the upper plate portion 153 (equivalent to upper plate portion 106) of metal component 52 and the upper plate portion 151 (equivalent to upper plate portion 107) of metal component 53. In detector 82, the fixing portion 76 of the holding component 77 is provided between the lower plate portion 253 (equivalent to lower plate portion 206) of metal component 52 and the lower plate portion 251 (equivalent to lower plate portion 207) of metal component 53. In detector 83, the fixing portion 67 of the retaining component 66 is provided between the upper plate portion 153 (corresponding to the upper plate portion 109) of metal component 53 and the upper plate portion 151 (corresponding to the upper plate portion 110) of metal component 54. In detector 83, the fixing portion 76 of the retaining component 77 is provided between the lower plate portion 253 (corresponding to the lower plate portion 209) of metal component 53 and the lower plate portion 251 (corresponding to the lower plate portion 210) of metal component 54. In detector 84, the fixing portion 67 of the retaining component 66 is provided between the upper plate portion 153 (corresponding to the upper plate portion 112) of metal component 54 and the upper plate portion 151 (corresponding to the upper plate portion 101) of metal component 51. In detector 84, the fixing portion 76 of the retaining component 77 is provided between the lower plate portion 253 (corresponding to the lower plate portion 212) of metal component 54 and the lower plate portion 251 (corresponding to the lower plate portion 201) of metal component 51.

[0188] The holding parts 68 and 78 are bent relative to the fixing parts 67 and 76, and parts 6 and 7 face each other in the r direction (radial direction). The force (torque) in the θ direction can be detected by the relative displacement of parts 6 and 7 in the θ direction due to the deformation of the structure 5. Here, an example is shown in which the holding parts 66 and 77 are fixed to the reinforcing parts 56 and 57, but the reinforcing parts 56 and 57 may also have holding parts that hold parts 6 and 7, and parts 6 and 7 may be fixed to these holding parts of the reinforcing parts 56 and 57.

[0189] Figure 22(a) shows a configuration in which the structure 5 is made up of metal parts 51-54 and reinforcing parts 56 and 57, in addition to the use of shims 16 and 27. Four shims 16 are placed between the four metal parts 51-54 and the reinforcing part 56. Four shims 27 are placed between the four metal parts 51-54 and the reinforcing part 57. Here, the shims 16 and 27 are each divided into four, but they may also be made as a single continuous shim, similar to the reinforcing parts 56 and 57.

[0190] As shown in Figure 22(b), the shims 16 and 27 form gaps 1056 and 2057 between the reinforcing parts 56 and 57 and the metal parts 51 to 54, corresponding to the thickness of the shims 16 and 27. The joints 58 and 59 can be formed by welding the reinforcing parts 56 and 57, the shims 16 and 27, and the metal parts 51 to 54 together. The area of ​​the shims 16 and 27 that is welded to the metal parts 51 to 54 is preferably 25% or more, but may be 75% or less. The area of ​​the shims 16 and 27 that is not welded to the metal parts 51 to 54 is preferably 25% or more, but may be 75% or less.

[0191] The area of ​​reinforcing parts 56 and 57 (area when viewed from a plane in the z direction) is, for example, 3800 mm². 2 The combined area of ​​the upper surface 1 and lower surface 2, which include the metal parts 51-54, is, for example, 2500 mm². 2 Assuming that the entire upper surface 1 and lower surface 2 of metal parts 51-54 overlap with reinforcing parts 56 and 57, the overlapping area between reinforcing parts 56 and 57 and metal parts 51-57 is 2500 mm².2 That is. The total area of the four shims 16 is, for example, 1700 mm 2 and the same applies to the four shims 27. The thickness of the shims 16 and 27 is, for example, 30 μm. Among the upper surface portion 1 and the lower surface portion 2, the area of the portion that does not overlap with the shims 16 and 27 is 800 mm 2 (= 2500 mm 2 - 1700 mm 2 ). The areas of the gaps 1056 and 2057 are also 800 mm 2 . The area where the reinforcing parts 56 and 27 face the metal parts 51 to 54 through the front gaps 1056 and 2057, which occupies the overlapping area between the reinforcing parts 56 and 57 and the metal parts 51 to 54, is 32% (= 800 mm 2 ÷ 2500 mm 2 ). The area of one (substantially circular shape) of the welding parts 58 and 59 is approximately 20 mm 2 . When each of the welding parts 58 and 59 is provided at 48 locations, the total area of the welding parts 58 and 59 is 960 mm 2 respectively. The area of the welding parts 58 and 59 (960 mm 2 ) occupies 56.5% of the area of each of the shims 16 and 27 (1700 mm 2 ). It means that 43.5% of the area of each of the shims 16 and 27 is not welded.

[0192] FIG. 23 compares the relationship between the load (input) torque and the detected (output) torque when the torque shown in the θ direction of FIG. 3 is applied to the sensor 10 of the embodiments of FIGS. 21 and 22. In the characteristic acquisition of FIG. 23, the load (input) torque is continuously changed in the order of 0, +120, -⁃120, 0 [Nm]. In FIG. 23, when the torque changes in the direction from a negative value to a positive value, it becomes a downward convex curve, and when it changes in the direction from a positive value to a negative value, it becomes an upward convex curve. FIG. 23(a) shows the characteristics of the sensor 10 when the gaps 1056 and 2057 are not provided except for the shims 16 and 27 as shown in FIG. 22. FIG. 23(b) shows the characteristics of the sensor 10 when the gaps 1056 and 2057 are provided by the shims 16 and 27 as shown in FIG. 22.

[0193] In the sensor 10 without gaps 1056 and 2057, the friction between the metal parts 51-54 and the reinforcing parts 56 and 57 is relatively large, causing a delay in rotation due to torque load. As a result, there is a large difference in the output torque depending on the direction of rotation. For example, as shown in Figure 23(a), when the load (input) torque is 0, the detected (output) torques are values ​​1015 and 1016, but value 1015 is +15Nm and value 1016 is -15Nm, both of which are differences from the load (input) torque. On the other hand, in the sensor 10 with gaps 1056 and 2057 provided by shims 16 and 27, the friction between the metal parts 51-54 and the reinforcing parts 56 and 57 is relatively small. As a result, the delay in rotation due to torque load is less likely to occur, and the difference in the output torque depending on the direction of rotation is less likely to occur. For example, as shown in Figure 23(b), the detected (output) torques 1017 and 1018 when the load (input) torque is 0 are +0.8 Nm and -0.8 Nm, respectively, and the difference from the load (input) torque is smaller compared to the case in Figure 23(a).

[0194] Figure 24(a) shows a configuration in which a head unit 60, which includes a component 6 (detection head) and a holding component 66 for holding the component 6, and a scale unit 70, which includes a component 7 (scale) and a holding component 77 for holding the component 7, are facing each other in the r direction (radial direction). The holding component 66 is fixed to the reinforcing component 56, and the holding component 77 is fixed to the reinforcing component 57.

[0195] In Figure 24(b), the reinforcing part 56 has an extension 566, and part 6 is fixed to the extension 566. The reinforcing part 57 has an extension 576, and part 7 is fixed to the extension 576.

[0196] In Figure 24(b), the reinforcing part 56 has an extension 566, and part 6 is fixed to the extension 566. The reinforcing part 57 has an extension 576, and part 7 is fixed to the extension 576.

[0197] In Figure 24(c), part 6 is fixed to the metal part 51. The reinforcing part 57 has an extension 576, and part 7 is fixed to the extension 576.

[0198] Figure 25(a) is a perspective view showing a robot system 900 according to an embodiment. In Figure 25, workpiece WA is, for example, a ring-shaped member, and workpiece WB is, for example, a member having a projection. Article W0 is manufactured by fitting workpiece WA and workpiece WB together.

[0199] The robot system 900 comprises a robot 600, a controller 700 for controlling the robot 600, and a teaching pendant 800. The robot 600 is an example of the mechanical device 1000, and in this example, it is an articulated robot. The robot 600 has an articulated robot arm 601 and a robot hand 602, which is attached to the tip of the robot arm 601 and serves as an end effector, the end of the robot 600.

[0200] The controller 700 controls the rotation angle of each joint J1 to J6 of the robot arm 601. Under the control of the controller 700, the robot 600 can orient its end-hand to any of three directions at any three-dimensional position within its range of motion.

[0201] The teaching pendant 800 is a teaching means that transmits teaching point data to the controller 700, and is mainly used at the installation site of the robot system 900 for an operator to specify the movements of the robot 600. The teaching pendant 800 is equipped with an operating section that includes operating keys for moving, for example, the posture (position and angle) of the joints of the robot arm 601, or the position of a reference point placed at the tip of the robot 600. When some robot operation is performed using the operating section of the teaching pendant 800, the controller 700 controls the movement of the robot arm 601 in response to the operation of the teaching pendant 800. At that time, the controller 700 controls each part of the robot 600 by executing a robot control program.

[0202] The robot hand 602 has a hand body 620 and a plurality of fingers 621 that are openable and closable and supported on the hand body 620. By closing the plurality of fingers 661, the workpiece WA can be gripped, and by opening the plurality of fingers 621, the workpiece WA can be released from gripping. By gripping the workpiece WA using the plurality of fingers 621, the workpiece WA can be assembled to the workpiece WB.

[0203] The robot arm 601 has multiple links 611 to 616, which are rotatably connected at joints J1 to J6. The base 610 of the robot arm 601 is fixed to the frame 150. Each joint J1 to J6 of the robot arm 601 is provided with a drive mechanism having an electric prime mover (motor), etc. The electric motor is, for example, a servo motor. The drive mechanism for each joint J1 to J6 is equipped with an appropriate output according to the required torque. A sensor 10 is provided in at least one of the joints J1 to J6. The controller 700 controls the prime mover (motor) based on information obtained from the sensor 10. The mechanisms of each joint J1 to J6 may have the same configuration or may be different.

[0204] For example, in the case of a joint of a robot arm 601, the sensor 10 measures the drive torque of a motor (not shown) that drives the joint, that is, the rotational driving force applied from this motor to the link. This sensor 10 is positioned at a predetermined location on the drive shaft of a drive system consisting of a motor or a reduction gear located inside the joint, for example.

[0205] The robot arm 601 shown in Figures 25(a) and (b) is a robot arm having a configuration in which multiple links are interconnected via multiple joints (6 axes), for example in a serial link format. The robot hand 602, which is an end effector, is connected to link 616 at the tip of the robot arm 601. Links 611, 612, 613, 614, 615, and 616 of the robot arm 601 are connected, for example, via each joint, in this embodiment, joints J1, J2, J3, J4, J5, and J6.

[0206] The base 610 (base portion) and link 611 of the robot arm 601 are connected by a joint J1 that rotates around a rotation axis in the Z-axis direction. Joint J1 is assumed to have a range of motion of approximately ±180 degrees from the initial position. Links 611 and 612 of the robot arm 601 are connected by a joint J2. The rotation axis of joint J2 coincides with the Y-axis direction in the illustrated state. This joint J2 is assumed to have a range of motion of approximately ±80 degrees from the initial position.

[0207] Links 612 and 613 of the robot arm 601 are connected by joint J3. Joint J3 is assumed to have a range of motion of approximately ±70 degrees from the initial position. Links 613 and 614 of the robot arm 601 are connected by joint J4. Joint J4 is assumed to have a range of motion of approximately ±180 degrees from the initial position.

[0208] Links 614 and 615 of the robot arm 601 are connected by joint J5. The axis of rotation of joint J5 coincides with the Y-axis in the illustrated state. Joint J5 is assumed to have a range of motion of approximately ±120 degrees from the initial position. Links 615 and 616 of the robot arm 601 are connected by joint J6. Joint J6 is assumed to have a range of motion of approximately ±240 degrees from the initial position.

[0209] As described above, in this embodiment, the rotation axes of joints J1, J4, and J6 are arranged parallel (or coaxial) to the central axes (dotted lines) of the two links to which they are connected, so that the (relative) angle around the rotation axis of these two links can be changed. On the other hand, the rotation axes of joints J2, J3, and J5 are arranged so that the (relative) angle at which the central axes (same) of the two links to which they are connected can be changed.

[0210] Furthermore, a robot hand 602 (end effector), such as an (electric) hand or an (pneumatically driven) air hand, is connected to the tip of the link 616 of the robot arm 601 for performing assembly and movement tasks on the production line. This robot hand 602 (end effector) is attached to the link 616 by (semi)fixed means such as screws (not shown), or it is possible to attach it by a detachable means such as a latch (ratchet) (not shown). In particular, if the robot hand 602 is detachable, a method can be considered in which the robot arm 601 is controlled to attach, detach or replace the end effector placed at the supply position (not shown) by the robot's own movement.

[0211] Figure 25(b) is a schematic cross-sectional view of one of the joints J1 to J6. This joint connects link 630 and link 640. Link 630 includes a connecting member 635 supported by a bearing 634. The connecting member 635 and the sensor 10 are coupled to each other by a fixing member 650. The fixing member 660 is inserted into at least one of the holes 100 and 560 described above, and the fixing member 650 may be inserted into at least one of the holes 200 and 570 described above. Link 630 includes a motor 631 (prime mover, electric motor) that operates link 630 and link 640 relative to each other. The rotating shaft 632 of the motor 631 is connected to a reduction gear 633. The reduction gear 633 is coupled to the connecting member 635. In this way, the prime mover (motor 631) and the sensor 10 are coupled via the reduction gear 633. The sensor 10 is annular, and a connecting component 670 connecting links 630 and 640 is provided in the space enclosed by the sensor 10. The connecting component 670 is surrounded by at least four elastic parts (for example, eight elastic parts 31-38) included in the sensor 10. The connecting component 670 may be a mechanical part such as a motor 631 or a reduction gear 633 provided on link 630 or link 640, or a mechanical shaft that connects mechanical parts to each other. The connecting component 670 may also be a wiring component that electrically connects an electrical part provided on link 630 and an electrical part provided on link 640. Thus, using an annular sensor 10 and arranging the connecting component 670 to be enclosed by the sensor 10 is advantageous for miniaturizing the robot 600. Therefore, the annular reinforcing components 56 and 57 shown in Figure 20(b) are preferred over the disc-shaped reinforcing components 56 and 57 shown in Figure 21(a). The force applied to at least one of links 630 and 640 deforms the structure 5 of the sensor 10, and this deformation is detected by the detection means 8. For example, the sensor 10 can be used as a torque sensor to detect torque around the axis 680.

[0212] Robot 600, equipped with a torque sensor and capable of torque control, is often used for assembling automobile engine parts with loads of several kilograms or parts with loads of several hundred grams. On the other hand, robot 600 is not often used for assembling tiny parts weighing only a few grams, or for handling thin films or sheets, where the load applied to the parts during assembly is only a few grams. This is because the force (torque) control accuracy of conventional articulated robots is not very high, and they have not been able to achieve the required accuracy for assembling parts with loads of only a few grams applied to the parts by the end effector at the tip of the robot arm 601. The sensor 10 of this embodiment can be used as an inexpensive and highly accurate torque sensor, enabling robot 600 to handle tiny workpieces with precise movements.

[0213] The robot 600 shown in Figure 25(a) may be a collaborative robot. In the manufacturing of goods using a collaborative robot, the robot 600 works in cooperation with a person to manufacture goods within a range of 1 meter from the person. In such a manufacturing method, when a person comes into contact with the robot 600, the sensor 10 installed on the robot 600 can detect the contact and control actions such as stopping the robot's operation can be taken. By reducing the cost of the sensor 10 installed on the robot 600, the cost of the robot 600 can be reduced, which in turn can reduce the cost of products manufactured using the collaborative robot manufacturing method and improve the safety of the manufacturing method.

[0214] The embodiments described above can be modified as appropriate without departing from the technical concept. For example, multiple embodiments can be combined. Furthermore, some aspects of at least one embodiment can be deleted or replaced. Furthermore, new aspects can be added to at least one embodiment.

[0215] Furthermore, the disclosures in this specification include not only what is explicitly stated herein, but also all matters that can be understood from this specification and the drawings attached thereto. In addition, the disclosures in this specification include the complement of the individual concepts described herein. That is, if this specification states, for example, "A is B," then even if the description of the case where "A is not B" is omitted, this specification can be said to disclose the case where "A is not B." This is because the statement "A is B" presupposes that the case where "A is not B" is being considered. [Explanation of symbols]

[0216] 31-38 Elastic part 5 Structure 51-54 Metal parts 56, 57 Reinforcement parts 8. Detection means

Claims

1. A structure having at least four elastic parts discretely arranged in a virtual plane, A sensor comprising detection means for detecting deformation of the aforementioned structure, The aforementioned structure is Metal parts formed by bending sheet metal, A first reinforcing part connected to the aforementioned metal part, It includes a second reinforcing part connected to the aforementioned metal part, Within the aforementioned plane, the four elastic parts are arranged such that a virtual circle passes through the four elastic parts. The metal part has an upper surface portion provided in a plane parallel to the virtual plane on one side, a lower surface portion provided in a plane parallel to the virtual plane on the other side, and at least one of the four elastic portions. The first reinforcing component is positioned on one side of the virtual plane and connected to the upper surface, and the second reinforcing component is positioned on the other side of the virtual plane and connected to the lower surface. The elastic portion of the metal member includes both sides in the thickness direction of the sheet metal, and the sensor is arranged such that the circle passes through both sides.

2. The metal part has at least a first elastic part and a second elastic part among the four elastic parts, The first reinforcing component has a first overlapping portion that overlaps the first elastic portion, a second overlapping portion that overlaps the second elastic portion, and a first relay portion that connects the first overlapping portion and the second overlapping portion. The sensor according to claim 1, wherein the second reinforcing part has a third overlapping portion that overlaps the first elastic portion, a fourth overlapping portion that overlaps the second elastic portion, and a second relay portion that connects the third overlapping portion and the fourth overlapping portion.

3. The sensor according to claim 2, wherein the distance between the first overlapping portion and the metal part is less than the thickness of the first elastic portion, and the distance between the fourth overlapping portion and the metal part is less than the thickness of the second elastic portion.

4. The metal part comprises a first metal part that satisfies at least one of the following conditions: overlapping the first relay portion and connecting the first elastic portion and the second elastic portion, The metal part has a second metal part that satisfies at least one of the following conditions: overlapping the second relay part and connecting the first elastic part and the second elastic part. The sensor according to claim 2 or 3, wherein a gap is provided between the first metal part and the second metal part.

5. The thickness of the first relay portion is greater than the thickness of the first metal portion. The sensor according to claim 4, wherein the thickness of the second relay portion is greater than the thickness of the second metal portion.

6. The thickness of the first relay portion is less than the distance between the first metal portion and the second metal portion. The thickness of the second relay portion is less than the distance between the first metal portion and the second metal portion. The sensor according to claim 4 or 5.

7. The difference between the thickness of the first elastic part and the thickness of the first metal part is smaller than the difference between the thickness of the first relay part and the thickness of the first metal part. The difference between the thickness of the second elastic portion and the thickness of the second metal portion is smaller than the difference between the thickness of the second relay portion and the thickness of the second metal portion. The sensor according to any one of claims 4 to 6.

8. The distance between the first metal part and the second metal part is 2 / 3 or more of the distance between the first relay part and the second relay part. The sensor according to any one of claims 4 to 7.

9. The sensor according to any one of claims 4 to 8, wherein the thickness of the first relay portion is between the distance between the first metal portion and the second metal portion and the thickness of the first metal portion, and the thickness of the second relay portion is between the distance between the first metal portion and the second metal portion and the thickness of the second metal portion.

10. The thickness of the first overlapping portion is less than the distance between the first overlapping portion and the third overlapping portion, The thickness of the third overlapping portion is less than the distance between the first overlapping portion and the third overlapping portion, The thickness of the first relay portion is less than the distance between the first relay portion and the second relay portion, The thickness of the second relay portion is less than the distance between the first relay portion and the second relay portion, The thickness of the first relay portion is greater than the thickness of the first elastic portion, The thickness of the second relay portion is greater than the thickness of the second elastic portion, The distance between the first overlapping portion and the metal part is smaller than the thickness of the first overlapping portion. The distance between the third overlapping portion and the metal part is less than the thickness of the third overlapping portion, The distance between the first relay portion and the metal part is less than the thickness of the first relay portion, The distance between the second relay portion and the metal part is less than the thickness of the second relay portion, A sensor according to any one of claims 2 to 9, which satisfies at least one of the following conditions.

11. A gap is provided between the first reinforcing part and the metal part, as described in any one of claims 1 to 10.

12. The sensor according to claim 11, wherein the area in which the first reinforcing component and the metal component face each other through the gap is 25% or more of the area in which the first reinforcing component and the metal component overlap.

13. The sensor according to claim 11 or 12, wherein either the first reinforcing part or the metal part has a plurality of protrusions, and the gap is provided between the plurality of protrusions.

14. The sensor according to claim 11 or 12, wherein a shim is provided between the first reinforcing component and the metal component.

15. The sensor according to any one of claims 1 to 14, wherein in a direction perpendicular to the plane, the upper surface portion, the lower surface portion, and the elastic portion of the metal part are located between the first reinforcing part and the second reinforcing part.

16. The sensor according to any one of claims 1 to 15, wherein in a direction perpendicular to the plane, the upper surface is located between the lower surface and the second reinforcing part.

17. The sensor according to any one of claims 1 to 16, wherein the first reinforcing part and the second reinforcing part are welded to the metal part.

18. The sensor according to any one of claims 1 to 17, wherein the metal part having the first elastic part and the second elastic part is defined as the first metal part, and the structure includes a second metal part having at least the third elastic part and the fourth elastic part of the four elastic parts.

19. The first reinforcing component is connected to the second metal component. The second reinforcing component is connected to the second metal component, The sensor according to claim 18, wherein the second metal component is provided between the first reinforcing component and the second reinforcing component.

20. The sensor according to any one of claims 1 to 19, wherein the thickness of the first reinforcing component in a direction perpendicular to the plane and the thickness of the second reinforcing component in a direction perpendicular to the plane are greater than the thickness of the elastic component in the circumferential direction of the circle.

21. A device comprising: a first link; a second link that operates relative to the first link; and a sensor according to any one of claims 1 to 20 coupled to the first link and the second link.

22. The apparatus according to claim 21, wherein the apparatus is a multi-joint robot.

23. The apparatus according to claim 21 or 22, further comprising a prime mover for moving the first link and the second link relative to each other.

24. The apparatus according to claim 23, wherein the prime mover and the sensor are coupled via a reduction gear.

25. A system comprising the device described in claim 23 or 24, and a control controller that controls the prime mover based on information obtained from the sensor.

26. A method for manufacturing an article, wherein the apparatus described in any one of claims 21 to 25 manufactures the article in cooperation with the person within a range of 1 meter from the person.

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