Torque sensor, actuator, and humanoid robot

Abstract

To provide a torque sensor, an actuator and a humanoid robot capable of suppressing a height in an axial direction.SOLUTION: The torque sensor 10 includes the photosensor 11 and the light reception amount varying member 19, one of the photosensor 11 and the light reception amount varying member 19 is directly or indirectly attached to the shaft 23 at a first position, the other is directly or indirectly attached to the shaft 23 at a second position separated in the axial direction Q, and the light reception amount varying member 19 extends in a direction intersecting the axial direction Q and is related to the photosensor 11. The actuator 1 includes a torque sensor 10 and a rotary body 20. The humanoid robot includes the actuator 1, a first element, and a second element rotatably connected to the first element via the actuator 1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a torque sensor, an actuator, and a humanoid robot. [Background technology]

[0002] Torque sensors are often used in robots that perform tasks that require highly sensitive responses to force. Patent Document 1 describes a torque sensor that includes a photointerrupter attached to a first strain body and a light-shielding plate attached to a second strain body connected to the first strain body via a small-diameter connecting member extending in the z-axis direction, where the light-shielding plate extends in the z-axis direction to change the light-shielding rate of the photointerrupter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-190885 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the torque sensor described in Patent Document 1 requires length in the z-axis direction because the light shielding plate extends in the z-axis direction (i.e., the axial direction), and the dimensions of the actuator equipped with the torque sensor tend to be large in the z-axis direction.

[0005] In view of the above-mentioned problems, the present disclosure relates to providing a torque sensor, an actuator, and a humanoid robot that can reduce the height in the axial direction. [Means for solving the problem]

[0006] The torque sensor according to the present disclosure is a torque sensor that detects the torque of a rotating body having a shaft that rotates around a rotation axis, and comprises a photosensor having a light-emitting element and a light-receiving element, and a light-receiving amount variable member that varies the amount of light received by the light-receiving element from the light-emitting element, wherein one of the photosensor and the light-receiving amount variable member is attached directly or indirectly to the shaft at a first position, and the photosensor or the light-receiving amount variable member that is not attached to the shaft at the first position is attached directly or indirectly to the shaft at a second position away from the first position in the axial direction, which is the direction in which the rotation axis extends, and the light-receiving amount variable member extends in a direction intersecting the axial direction and is associated with the photosensor.

[0007] The actuator according to the present disclosure comprises the torque sensor described above and the rotating body, and one of the photosensor and the light-receiving amount variable member is attached directly or indirectly to the shaft at the first position, and the other of the photosensor and the light-receiving amount variable member that is not attached to the shaft at the first position is attached directly or indirectly to the shaft at the second position.

[0008] A humanoid robot according to the present disclosure includes the above actuator, a first element, and a second element rotatably connected to the first element via the actuator. [Effects of the Invention]

[0009] According to the present disclosure, the light-receiving amount varying member extends in a direction intersecting the axial direction and is associated with the photosensor, so that the height in the axial direction can be reduced. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic longitudinal cross-sectional view illustrating a general configuration of an actuator according to an embodiment of the present disclosure. [Figure 2](A) is an end view taken along the arrows II-II in Figure 1 showing an example of the planar shape of the shielding plate, (B) is an end view taken along the arrows II-II in Figure 1 showing another example of the planar shape of the shielding plate, and (C) is an end view taken along the arrows II-II in Figure 1 showing yet another example of the planar shape of the shielding plate. [Figure 3] 1 is a partial schematic configuration diagram of a humanoid robot according to an embodiment of the present disclosure. FIG. [Figure 4] FIG. 10 is a schematic vertical cross-sectional view illustrating a schematic configuration of an actuator according to a modified example of the embodiment of the present disclosure. [Figure 5] 1A is a schematic partial longitudinal cross-sectional view showing the general configuration of an actuator according to another modified example of an embodiment of the present disclosure, and FIG. 1B is a schematic partial longitudinal cross-sectional view showing the general configuration of an actuator according to yet another modified example of an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, identical or similar reference numerals are used to designate identical or corresponding components, and redundant explanations will be omitted. Furthermore, the dimensions and proportions of the drawings are exaggerated for the sake of explanation and may differ from the actual proportions.

[0012] <Representative example of embodiment> First, an actuator 1 according to an embodiment of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a schematic vertical cross-sectional view showing a general configuration of an actuator 1 according to a second embodiment of the present disclosure, including a torque sensor 10 according to a first embodiment of the present disclosure. In addition to the torque sensor 10, the actuator 1 according to this embodiment includes a rotating body 20 and an encoder 30.

[0013] In this embodiment, the torque sensor 10 includes a photointerrupter 11, a torque sensor substrate 18, and a shielding plate 19. The photointerrupter 11 includes a light-emitting element 12 and a light-receiving element 14. The light-emitting element 12 is an element that emits light, and may be, for example, an LED. The light-receiving element 14 is an element that receives the light emitted from the light-emitting element 12. In the photointerrupter 11, a light-emitting surface 13 of the light-emitting element 12 and a light-receiving surface 15 of the light-receiving element 14 are arranged opposite each other with a gap in between. In this embodiment, the light-emitting element 12 and the light-receiving element 14 are arranged in a sensor exterior 16 having a space 17 formed therein. The light-emitting element 12 and the light-receiving element 14 are arranged such that the light-emitting surface 13 and the light-receiving surface 15, which face the space 17, sandwich the space 17 therebetween. The photointerrupter 11 is a so-called transmission type photosensor, in which the amount of light received by the light-receiving element 14 changes depending on the extent to which the shielding plate 19 penetrates into the space 17 between the light-emitting surface 13 and the light-receiving surface 15. In other words, the photointerrupter 11 is a type of photosensor.

[0014] The torque sensor board 18 is a board provided with an arithmetic circuit that calculates the torque of the object to be detected in accordance with changes in the amount of received light detected by the photointerrupter 11. In this embodiment, the torque sensor board 18 is equipped with the above-mentioned photointerrupter 11. The torque sensor board 18 can calculate the torque of the object to be detected based on the strain detected by the photointerrupter 11.

[0015] The shielding plate 19 enters the space 17 of the photointerrupter 11 to block at least a portion of the light traveling from the light-emitting element 12 to the light-receiving element 14, and thus corresponds to a shielding member. Furthermore, the shielding plate 19 changes the amount of light received by the light-receiving element 14 by changing the area that it blocks of the light traveling from the light-emitting element 12 to the light-receiving element 14 within the space 17, and thus corresponds to a light-receiving-amount adjusting member. The shielding plate 19 is disposed relative to the photointerrupter 11 so as to be reciprocatable in a direction intersecting (typically perpendicular to) the light traveling from the light-emitting element 12 to the light-receiving element 14. The shielding plate 19 is typically formed in a plate shape having a thickness smaller than the distance between the light-emitting surface 13 and the light-receiving surface 15. In other words, reducing the thickness of the shielding plate 19 makes it possible to reduce the distance between the light-emitting surface 13 and the light-receiving surface 15. The plate forming the shielding plate 19 typically has a uniform thickness and a flat surface, but is not limited to this and may have a thickness that varies depending on the location, or may have an uneven surface.

[0016] Here, the planar shape of the shielding plate 19 will be described with reference to Figures 2(A) to 2(C). Figures 2(A) to 2(C) are end views of the photointerrupter 11, the shielding plate 19, and the surrounding area, taken along the line II-II in Figure 1. Figures 2(A) to 2(C) each show the planar shape of the shielding plate 19 in the direction seen from the light-emitting element 12 to the light-receiving element 14, i.e., in the direction in which light travels from the light-emitting element 12 to the light-receiving element 14, and can also be said to show the shape in a planar view. In Figures 2(A) to 2(C), the shielding plate 19 moves back and forth in the movement direction R relative to the photointerrupter 11. Here, the shielding plate 19 moving relative to the photointerrupter 11 means that the shielding plate 19 moves and the photointerrupter 11 is stationary, the shielding plate 19 is stationary and the photointerrupter 11 moves, and both the shielding plate 19 and the photointerrupter 11 move.

[0017] As shown in FIG. 2(A), the shielding plate 19 may be a shielding plate 19A having a rectangular planar shape (i.e., a rectangle or a square). The shielding plate 19A having a rectangular planar shape is a shape that can be generally adopted. In the example shown in FIG. 2(A), the shielding plate 19A is arranged so that an edge 19AS (hereinafter referred to as a "light-shielding edge") that serves as a boundary for blocking light traveling from the light-emitting element 12 to the light-receiving element 14 extends perpendicular to the movement direction R. In the example shown in FIG. 2(A), the light blocking rate (area of ​​the light-receiving surface 15 blocked by the shielding plate 19 / area of ​​the entire light-receiving surface 15) of the light received by the light-receiving element 14 can be changed by adjusting the length of the light-receiving element 14 in the movement direction R.

[0018] As shown in FIG. 2(B), the shielding plate 19 may be a shielding plate 19B having a triangular planar shape. In this case, as in the example shown in FIG. 2(B), it is preferable that the light-shielding edge 19BS is disposed so as to extend obliquely with respect to the movement direction R (i.e., not perpendicular to and not parallel to the movement direction R). In the example shown in FIG. 2(B), the shielding rate of light received by the light-receiving element 14 can be changed by adding the length of the light-receiving element 14 in the movement direction R to the length of the light-shielding edge 19BS in the movement direction R in the range where the shielding plate 19B and the light-receiving element 14 overlap in a plan view. In this way, in the example shown in FIG. 2(B), the distance in the movement direction R over which the shielding rate of light received by the light-receiving element 14 can be changed can be made longer than in the example shown in FIG. 2(A), and the range in which the shielding plate 19 can be disposed relative to the photointerrupter 11 can be widened.

[0019] As shown in FIG. 2(C), the shielding plate 19 may be a shielding plate 19C having an elliptical planar shape. In the example shown in FIG. 2(C), the light-shielding edge 19CS extends in a direction that is neither perpendicular nor parallel to the movement direction R. In the example shown in FIG. 2(C), the shielding rate of light received by the light-receiving element 14 can be changed by adding the length of the light-receiving element 14 in the movement direction R to the length of the light-shielding edge 19CS in the movement direction R in the range where the shielding plate 19C and the light-receiving element 14 overlap in a plan view. In the example shown in FIG. 2(C), the distance in the movement direction R over which the shielding rate of light received by the light-receiving element 14 can be changed can be made longer than in the example shown in FIG. 2(A), and the range in which the shielding plate 19 can be arranged relative to the photointerrupter 11 can be widened.

[0020] Although not shown, the planar shape of the shielding plate 19 may be a triangle like the shielding plate 19B or an ellipse like the shielding plate 19C, or may be a polygon such as a hexagon or octagon, or a circle, or may be any of various other shapes. Regardless of the planar shape of the shielding plate 19, it is preferable to arrange the shielding plate 19 so that its light-shielding side extends in a direction that is neither perpendicular nor parallel to the moving direction R, since this widens the range in which the shielding plate 19 can be arranged relative to the photointerrupter 11. Note that even if the planar shape of the shielding plate 19A shown in FIG. 2(A) is rectangular, the same effect as that of the shielding plate 19B can be obtained if the light-shielding side 19AS is arranged so that it extends obliquely with respect to the moving direction R (i.e., neither perpendicular nor parallel to the moving direction R).

[0021] Referring again primarily to FIG. 1, the description of the configuration of the actuator 1 will continue. In this embodiment, the rotating body 20 has a motor 21, a reducer 22, a shaft 23, and an expansion member 25. The motor 21 is typically an electric motor that inputs electrical energy and outputs mechanical work. The motor 21 may also be a stepping motor or a servo motor. The reducer 22 is a device that reduces the rotational speed of the output shaft of the motor 21. The reducer 22 is typically configured to use multiple gears to reduce the rotational speed of the output shaft of the motor 21 to a desired rotational speed. Note that if the rotational speed of the output shaft of the motor 21 can be used as is and there is no need to reduce the rotational speed, the reducer 22 need not be provided (can be omitted).

[0022] Shaft 23 is a member that rotates due to the output of motor 21. Shaft 23 is typically formed in the shape of an elongated rod, and in this embodiment, it is formed in the shape of a round rod. Shaft 23 has axis 24 that connects the centers of gravity of cross sections perpendicular to the longitudinal direction in the longitudinal direction. Axis 24 extends linearly. Shaft 23 rotates around axis 24, and first end 23A is connected to motor 21 via reducer 22. In shaft 23 configured in this manner, axis 24 corresponds to the axis of rotation.

[0023] The extension member 25 is a member that transmits the rotational motion of the shaft 23 to a position on the outer periphery of the shaft 23. In this embodiment, the extension member 25 is connected to the second end 23B of the shaft 23. The second end 23B is the end of the shaft 23 opposite to the first end 23A. In this embodiment, the extension member 25 has an orthogonal member 26 that extends perpendicular to the axis 24 and a parallel member 27 that extends parallel to the axis 24. The orthogonal member 26 may be inclined with respect to an imaginary line (not shown) that is perpendicular to the axis 24, and the parallel member 27 may extend at an angle relative to the axis 24. In this embodiment, the orthogonal member 26 is connected to the second end 23B. The orthogonal member 26 may be formed in a disk shape, or may be formed of a plurality of rod-shaped members extending radially from the shaft 23 to form a hub-and-spoke configuration with the shaft 23 as the hub. In this embodiment, the parallel member 27 is attached to the outer periphery of the orthogonal member 26 so as to extend toward the motor 21. The parallel member 27 may be provided along the entire outer periphery of the orthogonal member 26, or may be provided intermittently.

[0024] The encoder 30 is a device that measures the rotation angle of the shaft 23, and in this embodiment, a magnetic rotary encoder is used. In this embodiment, the encoder 30 has a magnet 31 and an encoder board 32. The encoder board 32 has a magnetic sensor 33. In this embodiment, the magnet 31 is attached to the extension member 25, and the encoder board 32 is attached to the housing (not shown) of the actuator 1. The magnet 31 is attached to the shaft 23 via the extension member 25, and in this embodiment, it is attached to the end of the parallel member 27 opposite to the end to which the orthogonal member 26 is attached, in a manner extending in a direction intersecting with the direction in which the axis 24 extends (hereinafter referred to as the "axial direction Q"). Therefore, in this embodiment, the magnet 31 is attached to the rotating body 20 and is part of the actuator 1, other than the torque sensor 10, that extends in a direction intersecting with the axial direction Q. When the magnet 31 rotates around the axis 24 as the shaft 23 rotates around the axis 24, the magnetic sensor 33 detects the change in the direction of the magnetic field, thereby determining the rotational position of the shaft 23.

[0025] In the present embodiment, the actuator 1 has a torque sensor board 18 attached to the side of the shaft 23, and a shielding plate 19 attached to the magnet 31. The position at which the torque sensor board 18 is attached to the shaft 23 is between the first end 23A and the second end 23B, away from the extension member 25 in the axial direction Q, and corresponds to the first position. In the present embodiment, the photointerrupter 11 is attached to the torque sensor board 18, and therefore can be said to be indirectly attached to the shaft 23 at the first position via the torque sensor board 18. The photointerrupter 11 is attached to the shaft 23 via the torque sensor board 18 with the light-emitting element 12 and the light-receiving element 14 aligned in the axial direction Q. The photointerrupter 11 is typically arranged so that light traveling from the light-emitting element 12 to the light-receiving element 14 travels in the axial direction Q.

[0026] The shielding plate 19 is attached to the magnet 31 so as to extend in a direction intersecting the axial direction Q and be involved in the photointerrupter 11. Here, the shielding plate 19 being involved in the photointerrupter 11 means that the shielding plate 19 is disposed in a position where it can affect the amount of light received by the photointerrupter 11. The shielding plate 19 is attached to the extension member 25 via the magnet 31. If the position where the extension member 25 is attached to the shaft 23 is defined as the second position, then the shielding plate 19 can be said to be indirectly attached to the shaft 23 at the second position via the magnet 31 and the extension member 25.

[0027] In the actuator 1, the shielding plate 19 extends in a direction intersecting the axial direction Q and enters the space 17 of the photointerrupter 11, so the height in the axial direction Q can be reduced compared to conventional actuators in which the shielding plate is disposed extending in the axial direction. In particular, it is preferable for the shielding plate 19 to extend perpendicular to the axial direction Q and enter the space 17, as this can most effectively reduce the height in the axial direction Q. Here, "extending perpendicular to the axial direction Q" means that the shielding plate 19 is essentially perpendicular to the axial direction Q. Therefore, "extending perpendicular to the axial direction Q" of the shielding plate 19 includes, for example, a state in which deviation within the range of error during assembly is permitted, or a state in which the shielding plate 19 is tilted to an extent that does not impair the intended function (for example, a state in which the shielding plate is tilted within ±10° of the perpendicular angle).

[0028] The shielding plate 19 and the magnet 31 may be formed integrally. Examples of integral formation include a state in which the shielding plate 19 and the magnet 31 are directly bonded with an adhesive or the like, a state in which they are integrally formed by integral molding or the like so that there is no physical boundary between them, and a state in which the magnet 31 also serves as the shielding plate 19. If the magnet 31 extends in a direction intersecting the axial direction Q until it enters the space 17 of the photointerrupter 11 and also serves as the shielding plate 19, the shielding plate 19 is part of the magnet 31, which is a component of the actuator 1 attached to the rotating body 20 and extends in a direction intersecting the axial direction Q. In this case, a component of the encoder 30, which is a component other than the torque sensor 10 of the actuator 1, also serves as the shielding plate 19. If a component other than the torque sensor 10 of the actuator 1 also serves as the shielding plate 19, the number of components of the actuator 1 can be reduced. Furthermore, if a component of the encoder 30 doubles as the shielding plate 19, it is possible to detect both the rotation angle and torque of the rotating body 20 with a reduced number of components. Also, if the magnet 31 doubles as the shielding plate 19, it is possible to detect both the rotation angle and torque of the rotating body 20 with a relatively simple configuration.

[0029] Continuing to primarily refer to FIG. 1 , the operation of the actuator 1 will be described. Note that the operation of the torque sensor 10 will be described as part of the operation of the actuator 1. In the actuator 1 configured as described above, when electrical energy is input to the motor 21, the output of the motor 21 is transmitted to the shaft 23 via the reducer 22, causing the shaft 23 to rotate about an axis 24. When the shaft 23 rotates about the axis 24, a torsion angle proportional to the torque is generated in the shaft 23. In the actuator 1, the photointerrupter 11 and the shielding plate 19 are indirectly connected to the shaft 23 at a first position and a second position spaced apart in the axial direction Q. Therefore, the torsion angle generated in the shaft 23 appears as a change in the amount of light received by the light-receiving element 14. The torque sensor 10 detects the torque of the shaft 23 by performing calculations in the torque sensor board 18 based on the change in the amount of light received by the light-receiving element 14. As described above, in this embodiment, the shaft 23 is the object to be detected by the torque sensor 10. Since the height of the actuator 1 in the axial direction Q is relatively short, the distance between the first position and the second position tends to be short. However, if the strain detected as a result is small, it may be amplified by software processing on the torque sensor board 18.

[0030] Furthermore, when the shaft 23 of the actuator 1 rotates around the axis 24, the magnet 31 attached to the shaft 23 via the extension member 25 moves relative to the encoder board 32 attached to the housing (not shown) of the actuator 1. When the magnet 31 moves relative to the magnetic sensor 33 included in the encoder board 32, the magnetic sensor 33 detects a change in the magnetic field corresponding to the amount of movement of the magnet 31. The encoder 30 calculates the rotation angle of the shaft 23 by performing calculations on the encoder board 32 based on the change in the magnetic field detected by the magnetic sensor 33. This makes it possible to determine the rotation angle of the shaft 23.

[0031] FIG. 3 shows an example in which the actuator 1 is applied to a humanoid robot 100. FIG. 3 is a partial schematic diagram of the humanoid robot 100. FIG. 3 shows the area around one leg of the humanoid robot 100. As described above, the actuator 1, which can detect the torque and rotation angle of the shaft 23, can be suitably applied to the joints of the humanoid robot 100. The humanoid robot 100 has a leg 101 as a first element and a foot 102 as a second element, which are connected via the actuator 1. In this embodiment, the leg 101 is connected to the housing of the actuator 1, and the foot 102 is connected to the extension member 25 via a connection structure 103. With this configuration, the humanoid robot 100 is connected so that the foot 102 can rotate relative to the leg 101. For convenience of explanation, the example shown in FIG. 3 uses one actuator 1, but by combining multiple actuators 1, it is possible to move the foot 102 three-dimensionally relative to the leg 101. The actuator 1 according to this embodiment can be made smaller by reducing its height in the axial direction Q, so that a relatively small torque is required for movement, and when applied to a joint of a humanoid robot, smooth movement of the joint can be achieved. Note that the joints of the humanoid robot 100 to which the actuator 1 can be applied are not limited to the ankle, but can also be applied to various joints such as the knee, shoulder, elbow, and / or hip joint.

[0032] As described above, according to the torque sensor 10 according to the first embodiment of the present disclosure, the shielding plate 19 can be attached to the shaft 23 so as to extend in a direction intersecting the axial direction Q, thereby reducing the height in the axial direction Q. In particular, when the shielding plate 19 is arranged so as to extend in a direction perpendicular to the axial direction Q, the height in the axial direction Q can be further reduced. Furthermore, when the shielding plate 19 is arranged so that its light-shielding edge extends in a direction that is neither perpendicular nor parallel to the movement direction R, the range in which the shielding plate 19 can be arranged relative to the photointerrupter 11 can be widened. Furthermore, according to the actuator 1 according to the second embodiment of the present disclosure that includes the torque sensor 10, the magnet 31 and the shielding plate 19, which are components of the encoder 30, are integrally configured, thereby reducing the number of components and enabling detection of both the rotation angle and torque of the rotating body 20.

[0033] <Modification> Next, an actuator 2 according to a modified example of the second embodiment of the present disclosure will be described with reference to FIG. 4. FIG. 4 is a schematic longitudinal cross-sectional view showing a general configuration of the actuator 2. Compared to the actuator 1 (see FIG. 1), the actuator 2 is similar in that it includes a torque sensor 10, a rotating body 20, and an encoder 30, but differs in the arrangement of the torque sensor 10 and the encoder 30. The rotating body 20 of the actuator 2 has the same configuration as that of the actuator 1 (see FIG. 1). Below, differences in the configuration of the actuator 2 from the actuator 1 (see FIG. 1) will be mainly described.

[0034] In the actuator 2, the photointerrupter 11 is directly attached to the shaft 23 at a first position, and the torque sensor board 18 is attached to the orthogonal member 26. The photointerrupter 11 and the torque sensor board 18 are electrically connected by an electric wire (not shown) or wirelessly, and an optical signal detected by the photointerrupter 11 can be sent as an electrical signal to the torque sensor board 18. The shielding plate 19 is attached to the parallel member 27 via the encoder board 32. The shielding plate 19 may be configured integrally with the encoder board 32. Being configured integrally includes a state in which the shielding plate 19 and the encoder board 32 are directly bonded with an adhesive or the like, or a state in which they are integral, as well as a state in which the encoder board 32 extends in a direction intersecting the axial direction Q until it enters the space 17 of the photointerrupter 11 and doubles as the shielding plate 19. In either embodiment, the shielding plate 19 is provided to extend in a direction intersecting (preferably perpendicular to) the axial direction Q.

[0035] Furthermore, in the actuator 2, the magnet 31 constituting the encoder 30 is attached to the housing (not shown) of the actuator 2, and the encoder board 32 is attached to the parallel member 27 of the extension member 25 as described above. In this embodiment, the encoder board 32 is attached to the upper end of the parallel member 27 so as to extend in a direction intersecting (preferably perpendicular to) the axial direction Q. Other than the above, the configuration of the actuator 2 is the same as that of the actuator 1 (see FIG. 1), including the planar shape of the shielding plate 19, etc.

[0036] In the actuator 2 configured as described above, similarly to the actuator 1 (see FIG. 1), when the rotating body 20 rotates around the axis 24, a torsion angle proportional to the torque is generated in the shaft 23, and this torsion angle is expressed as a change in the amount of light received by the light-receiving element 14. The torque sensor 10 detects the torque of the shaft 23 based on the change in the amount of light received by the light-receiving element 14. Furthermore, when the rotating body 20 rotates around the axis 24, the encoder board 32 attached to the shaft 23 via the extension member 25 moves relative to the magnet 31 attached to the housing (not shown) of the actuator 2. In the encoder 30, the magnetic sensor 33 detects a change in the magnetic field corresponding to the amount of movement of the encoder board 32, and detects the rotation angle of the shaft 23 based on the change in the magnetic field detected by the magnetic sensor 33.

[0037] In the actuator 2, the shielding plate 19 is also provided so as to extend in a direction intersecting the axial direction Q, thereby reducing the height in the axial direction Q. Furthermore, the encoder board 32, which is a component of the encoder 30, and the shielding plate 19 are integrally configured, thereby reducing the number of components and enabling detection of both the rotation angle and torque of the rotating body 20. The actuator 2 differs from the actuator 1 (see FIG. 1) in that the arrangements of the torque sensor 10 and the encoder 30 may be changed from those of the actuator 1 (see FIG. 1). For example, the photointerrupter 11 may be indirectly attached to the shaft 23 at a first position via the torque sensor board 18, as in the actuator 1 (see FIG. 1), while the shielding plate 19 may be attached to the extension member 25 via the encoder board 32. Alternatively, the shielding plate 19 may be attached to the extension member 25 via the magnet 31, as in the actuator 1 (see FIG. 1), while the photointerrupter 11 may be directly attached to the shaft 23 at a first position without the torque sensor board 18.

[0038] The components of the torque sensor 10, the rotating body 20, and the encoder 30 may be arranged in various ways other than the arrangement of the actuator 2, without departing from the spirit of the present disclosure.

[0039] For example, as shown in FIG. 5A, the shielding plate 19 may be indirectly attached to the shaft 23 at a first position via a magnet 31, and the photointerrupter 11 may be indirectly attached to the shaft 23 at a second position via an extension member 25 and a torque sensor board 18. The rotating body 20 in the actuator 3 has a configuration similar to that of the rotating body 20 of the actuator 1 (see FIG. 1). The shielding plate 19 is attached to the shaft 23 via the magnet 31 so as to extend in a direction intersecting (preferably perpendicular to) the axial direction Q. The encoder board 32 may be attached to a housing (not shown) of the actuator 3. Note that the magnet 31 and the encoder board 32 may be interchanged in this arrangement. The shielding plate 19 may be directly attached to the shaft 23, or may be indirectly attached to the shaft 23 via a component of the actuator 3 other than the encoder 30. In the actuator 3, the photointerrupter 11 is attached to the parallel member 27 via the torque sensor board 18 in a direction in which the light-emitting element 12 and the light-receiving element 14 are aligned in the axial direction Q. The photointerrupter 11 may be attached to the extension member 25 via a component of the actuator 3 other than the torque sensor board 18.

[0040] Alternatively, as shown in FIG. 5B, the shielding plate 19 may be indirectly attached to the shaft 23 at a first position via an extension member 25 and a magnet 31, and the photointerrupter 11 may be directly attached to the shaft 23 at a second position. The rotating body 20A in the actuator 4 has an extension member 25 connected to the first position between the first end 23A and the second end 23B of the shaft 23. The extension member 25 has an orthogonal member 26 extending perpendicular to the axial direction Q, and a parallel member 27 extending from the outer circumferential end of the orthogonal member 26 toward the second end 23B. The shielding plate 19 is attached to the shaft 23 via the magnet 31 and the extension member 25 so as to extend in a direction intersecting (preferably perpendicular to) the axial direction Q. The encoder board 32 may be attached to the housing (not shown) of the actuator 4. The magnet 31 and the encoder board 32 may be interchanged from this arrangement. Furthermore, the shielding plate 19 may be attached to the extension member 25 via a component of the actuator 4 other than the encoder 30 .

[0041] Although not shown, the components of the actuator to which the shielding plate 19 is attached or to which it becomes a part are not limited to the magnet 31 or the encoder board 32. The shielding plate 19 may be attached to any of the components of the actuator that are attached to the rotating body and extend in a direction intersecting with the axial direction Q, or may be part of the components of the actuator that are attached to the rotating body and extend in a direction intersecting with the axial direction Q.

[0042] The actuators 2, 3, and 4 according to the respective modifications can also be applied to the humanoid robot 100 in place of the actuator 1 or together with the actuator 1.

[0043] <Other> In the above description, the photosensor is the photointerrupter 11, which is a transmissive photosensor. However, a photoreflector, which is a reflective photosensor, may also be used. A photoreflector is similar to the photointerrupter 11 in that it has a light-emitting element and a light-receiving element, but the light-emitting surface of the light-emitting element and the light-receiving surface of the light-receiving element are arranged adjacent to each other with the light-emitting surface of the light-emitting element facing the same direction. A reflector is arranged opposite the light-emitting surface and the light-receiving surface of the photoreflector. When a photoreflector and a reflector are used in a torque sensor, light emitted from the light-emitting element is reflected by the reflector and directed toward the light-receiving element. The reflector changes the amount of light reflected, i.e., the amount of light received by the light-receiving element, by changing the distance from the photoreflector, and corresponds to a light-receiving amount variable member. Note that the reflector is not limited to a plate-shaped member; any member (hereinafter referred to as a "reflective member") capable of reflecting light emitted from the light-emitting element will suffice. When a photoreflector is used instead of the photointerrupter 11, a reflector may be provided instead of the shielding plate 19.

[0044] In the above description, the encoder is a magnetic encoder 30, but it may also be an optical encoder. An optical encoder typically includes a photointerrupter and an encoder disk. The photointerrupter of the optical encoder may have a configuration similar to that of the photointerrupter 11 of the torque sensor 10. The encoder disk has slits formed at predetermined intervals, and is arranged so that the outer periphery of the encoder disk fits into the space between the light-emitting element and the light-receiving element of the photointerrupter. Typically, an optical encoder detects the rotation angle of the rotating body by detecting with the light-receiving element whether or not light emitted from the light-emitting element passes through the slits in the encoder disk as the encoder disk moves within the space of the photointerrupter. When an optical encoder is used, the shielding plate 19 of the torque sensor 10 may be formed integrally with the encoder disk. Forming the shielding plate 19 integrally includes a state in which the shielding plate 19 and the encoder disk are directly bonded with an adhesive or the like, a state in which they are integral, and a state in which the encoder disk also serves as the shielding plate 19. In this way, the shielding plate 19 can be formed integrally with the magnet 31 or the encoder substrate 32 when the encoder 30 is magnetic, or it can be formed integrally with the encoder components when the encoder is optical. The optical encoder described above is a transmission type, but a reflective optical encoder may also be used.

[0045] <Additional Notes> The following are additional notes regarding this disclosure.

[0046] (Appendix 1) A torque sensor for detecting torque of a rotating body having a shaft that rotates around a rotation axis, a photosensor having a light emitting element and a light receiving element; a light receiving amount varying member that varies the amount of light received by the light receiving element from the light emitting element, one of the photosensor and the light-receiving amount varying member is directly or indirectly attached to the shaft at a first position; one of the photosensor and the light-receiving amount variable member that is not attached to the shaft at the first position is attached directly or indirectly to the shaft at a second position away from the first position in an axial direction that is a direction in which the rotation axis extends, the light-receiving amount varying member extends in a direction intersecting the axial direction and is connected to the photosensor; Torque sensor.

[0047] (Appendix 2) The light-receiving amount varying member extends perpendicular to the axial direction and is connected to the photosensor. 10. The torque sensor according to claim 1.

[0048] (Appendix 3) the photosensor is a photointerrupter in which a light emitting surface of the light emitting element and a light receiving surface of the light receiving element are arranged opposite to each other, the light-receiving amount varying member is a shielding member that blocks at least a portion of the light traveling from the light-emitting element to the light-receiving element, the shielding member is formed in a plate shape that blocks a part of the light traveling from the light emitting element to the light receiving element when viewed in the direction in which the light travels from the light emitting element to the light receiving element, and a side of the plate that becomes a boundary that blocks a part of the light extends in a direction that is neither perpendicular nor parallel to a moving direction in which the shielding member moves relative to the photointerrupter; 10. The torque sensor according to claim 1 or 2.

[0049] (Appendix 4) A torque sensor according to any one of Supplementary Note 1 to Supplementary Note 3; the rotating body, one of the photosensor and the light-receiving amount varying member is directly or indirectly attached to the shaft at the first position; the photosensor and the light-receiving amount adjusting member, whichever is not attached to the shaft at the first position, is attached directly or indirectly to the shaft at the second position; Actuator.

[0050] (Appendix 5) the light-receiving amount adjusting member is attached to a component of the actuator that is attached to the rotating body and extends in a direction intersecting the axial direction, or is a part of the component of the actuator; 5. The actuator of claim 4.

[0051] (Appendix 6) an encoder for detecting a rotation angle of the rotating body; The encoder components are integrally formed with the light-receiving amount varying member. 6. The actuator of claim 5.

[0052] (Appendix 7) the encoder is a magnetic encoder including a magnet and a substrate having a magnetic sensor that receives a magnetic field generated by the magnet; The magnet or the substrate is integrally formed with the light-receiving amount varying member. 7. The actuator of claim 6.

[0053] (Appendix 8) An actuator according to any one of Supplementary Note 4 to Supplementary Note 7; The first element, a second element rotatably connected to the first element via the actuator; Humanoid robot. [Explanation of symbols]

[0054] 1, 2, 3, 4 Actuators 10 Torque sensor 11 Photointerrupter (photosensor) 12 Light-emitting element 13 Light-emitting surface 14 Photodetector 15 Photosensitive surface 19 Shielding plate (shielding member, light receiving amount variable member) 20, 20A Rotating Body 23 Shaft 24 axis 30 Encoder 31 Magnet 32 Encoder board 33 Magnetic Sensor 100 Humanoid Robots 101 Leg (first element) 102 Flat of the foot (second element) Q Axial direction

Claims

1. A torque sensor for detecting torque of a rotating body having a shaft that rotates around a rotation axis, a photosensor having a light emitting element and a light receiving element; a light receiving amount varying member that varies the amount of light received by the light receiving element from the light emitting element, one of the photosensor and the light-receiving amount varying member is directly or indirectly attached to the shaft at a first position; one of the photosensor and the light-receiving amount variable member that is not attached to the shaft at the first position is attached directly or indirectly to the shaft at a second position away from the first position in an axial direction that is a direction in which the rotation axis extends, the light-receiving amount varying member extends in a direction intersecting the axial direction and is connected to the photosensor; Torque sensor.

2. The light-receiving amount varying member extends perpendicular to the axial direction and is connected to the photosensor. The torque sensor according to claim 1 .

3. the photosensor is a photointerrupter in which a light emitting surface of the light emitting element and a light receiving surface of the light receiving element are arranged opposite to each other, the light-receiving amount varying member is a shielding member that blocks at least a portion of the light traveling from the light-emitting element to the light-receiving element, the shielding member is formed in a plate shape that blocks a part of the light traveling from the light emitting element to the light receiving element when viewed in the direction in which the light travels from the light emitting element to the light receiving element, and a side of the plate that becomes a boundary along which the part of the light is blocked extends in a direction that is neither perpendicular nor parallel to a moving direction in which the shielding member moves relative to the photointerrupter; The torque sensor according to claim 1 .

4. The torque sensor according to any one of claims 1 to 3, the rotating body, one of the photosensor and the light-receiving amount varying member is directly or indirectly attached to the shaft at the first position; the photosensor and the light-receiving amount varying member, whichever is not attached to the shaft at the first position, is attached directly or indirectly to the shaft at the second position; Actuator.

5. the light-receiving amount adjusting member is attached to a component of the actuator that is attached to the rotating body and extends in a direction intersecting the axial direction, or is a part of the component of the actuator; The actuator according to claim 4 .

6. an encoder for detecting a rotation angle of the rotating body; The encoder components are integrally formed with the light-receiving amount varying member. The actuator according to claim 5 .

7. the encoder is a magnetic encoder including a magnet and a substrate having a magnetic sensor that receives a magnetic field generated by the magnet; The magnet or the substrate is integrally formed with the light-receiving amount varying member. The actuator according to claim 6.

8. The actuator according to claim 4; a first element; and a second element rotatably connected to the first element via the actuator; Humanoid robot.

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