Actuator

Abstract

The actuator includes a motor, a decelerator, a primary encoder, and a secondary encoder. The rotating disk of the secondary encoder is arranged concentrically with respect to the rotating disk of the primary encoder. The actuator includes a first coupling portion that couples the output shaft of the speed reducer and the rotating disk of the secondary encoder to each other.

Description

Technical Field

[0001] The present disclosure relates to an actuator. Background Art

[0002] The actuator includes a servo motor and a reducer connected to each other. The primary encoder (Japanese: プライマリエンコーダ) is connected to the motor shaft of the servo motor to detect the absolute position of the motor shaft within one rotation. Similarly, the secondary encoder is connected to the output shaft of the reducer to detect the absolute position of the output shaft within one rotation. In addition, the total number of rotations of the primary encoder and / or the secondary encoder is detected (for example, refer to Japanese Patent Publication No. 2012-171072).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-171072 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] In recent actuators, the motor shaft of the motor is made as a hollow shaft, and a primary encoder is installed on the rear end side thereof. In addition, the output shaft of the reducer passes through the motor shaft and extends toward the motor side, and a secondary encoder is installed on the rear end side of the output shaft. Therefore, the rotating disk of the secondary encoder is arranged concentrically with respect to the rotating disk of the primary encoder.

[0008] In such a structure, a relatively large space is required to fix the rotating disk of the secondary encoder to the output shaft of the speed reducer.

[0009] Therefore, an actuator capable of achieving space saving is desired.

[0010] Solutions for solving problems

[0011] According to the first scheme of the present disclosure, an actuator is provided, which comprises: a motor; a reducer connected to the motor; a primary encoder which detects the position of the motor shaft of the motor; and a secondary encoder which detects the position of the output shaft of the reducer, wherein the rotating disk of the secondary encoder is concentrically arranged relative to the rotating disk of the primary encoder, and the actuator comprises a first coupling portion which couples the output shaft of the reducer and the rotating disk of the secondary encoder to each other.

[0012] The objects, features, and advantages of the present disclosure will become more apparent from the following description of the embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1A It is an axial cross-sectional view of the actuator in the first embodiment of the present disclosure.

[0014] Figure 1B It is a partial exploded view of the actuator in the first embodiment.

[0015] Figure 1C It is a diagram showing a modification example of the first embodiment.

[0016] Figure 2A It is an axial cross-sectional view of the actuator in the second embodiment of the present disclosure.

[0017] Figure 2B It is a partial exploded view of the actuator in the second embodiment.

[0018] Figure 2C It is a diagram showing a modification example of the second embodiment.

[0019] Figure 3A It is an axial cross-sectional view of an actuator in a third embodiment of the present disclosure.

[0020] Figure 3B It is a partial exploded view of the actuator in the third embodiment.

[0021] Figure 4 It is an axial cross-sectional view of an actuator in another embodiment.

[0022] Figure 5 It is an axial cross-sectional view of an actuator in the prior art. DETAILED DESCRIPTION

[0023] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In all the drawings, corresponding components are denoted by common reference numerals.

[0024] Figure 1A This is an axial cross-sectional view of the actuator according to the first embodiment of the present disclosure. The actuator 5a is installed in a machine having an axis, such as a robot. The following describes the case where the actuator 5a is installed in the robot, but the same is true for the case where the actuator 5a is installed in other machines having an axis, such as a machine tool.

[0025] The actuator 5a mainly includes: an electric motor 10, such as a servo motor, which is composed of a stator 11 and a rotor 12; an electromagnetic brake B, which is connected to the electric motor 10; a reducer 20, which is connected to the motor shaft 13 of the electric motor 10; a force sensor S, which is combined with the reducer; and an encoder E.

[0026] In the present application, it is defined that the reducer 20 is arranged on the front side relative to the motor 10, and the motor 10 is arranged on the rear side relative to the reducer 20. In addition, in principle, it is defined that the "radial direction" in the present application refers to the radial direction of the actuator 5a, etc., and the "axial direction" refers to the axial direction of the actuator 5a, etc.

[0027] The motor 10 includes a rotor 12 that rotates integrally with a motor shaft 13, and a stator 11 that is disposed so as to surround the rotor 12. The front end of the output shaft 23 of the reducer 20 is connected to the connecting rod 2 (not shown) via a force sensor S. Therefore, the actuator 5 performs positioning control by relatively rotating the connecting rod 2 (not shown) relative to the actuator 5 within a predetermined range of motion. In addition, the reduction ratio of the reducer 20 is, for example, 1:50.

[0028] The motor shaft 13 is, for example, a hollow shaft, and a primary encoder 15 having a rotating disk 15A is mounted on the rear end thereof. The primary encoder 15 is, for example, an absolute encoder, and outputs an A-phase signal, a B-phase signal, and a Z-phase signal. The output signal is detected by a detection unit 15B, and the absolute position of the motor shaft 13 within one rotation and the total number of rotations of the motor shaft 13 are detected by a known method. The detected information is stored in a memory of the detection unit 15B, such as a volatile memory or a non-volatile memory.

[0029] The output shaft 23 of the speed reducer 20 is connected with an extension portion 23a such as a hollow tube, and the extension portion 23a extends toward the motor 10 side by passing through the hollow motor shaft 13. In addition, a secondary encoder 25 having a rotating disk 25A is mounted on the rear end of the extension portion 23a. In addition, the output shaft 23 of the speed reducer 20 and the extension portion 23a may be formed integrally. In other words, the extension portion 23a may be a part of the output shaft 23. Therefore, in the following, there is a case where the "extension portion 23a" is described as the "output portion 23".

[0030] The secondary encoder 25 is, for example, an absolute encoder, and outputs an A-phase signal, a B-phase signal, and a Z-phase signal. The output signal is detected by the detection unit 25B, and the absolute position and the total number of rotations of the output shaft 23 within one rotation are detected by a known method. The detected information is stored in a memory of the detection unit 25B, such as a volatile memory or a non-volatile memory. In addition, there is a case where the primary encoder 15 and the secondary encoder 25 are collectively referred to as an encoder E.

[0031] The force sensor S is composed of a torque sensor or the like that detects the force acting around the axis of the actuator 5a. The force sensor S preferably has a spring portion (not shown) that exhibits elasticity. When a force acts around the axis of the actuator 5a, the spring portion deforms, and thus the force acting around the axis can be detected by the amount of deformation of the spring portion. The force sensor S may also be a strain gauge type, an electrostatic capacitance type, a magnetic type, or an optical encoder type.

[0032] As shown in the figure, the force sensor S, reducer 20, motor 10, electromagnetic brake B, and encoder E, which are coaxially connected to each other, are preferably hollow structures. Furthermore, the hollow parts of these force sensor S, reducer 20, motor 10, electromagnetic brake B, and encoder E preferably have a common inner diameter. As a result, it is possible to smoothly configure an extension 23a, such as a hollow tube. Hereinafter, there is a case where the internal space of the force sensor S, the internal space of the reducer 20, the internal space of the motor 10, the internal space of the electromagnetic brake B, and the internal space of the encoder E are collectively referred to as the hollow part 22. In addition, it is assumed that at least one linear body (not shown) such as a signal line and a current supply line passes through the hollow part 22. In addition, it is assumed that even if the actuator 5a~5c is a structure that does not include the force sensor S and / or the electromagnetic brake B as described later, it is also included in the scope of the present disclosure. The same is true for other embodiments.

[0033] like Figure 1A As shown in the figure, a circular first support member 18 extending in the radial direction is mounted on the rear end of the motor shaft 13. An annular protrusion 18a is provided on the first support member 18, and preferably, the protrusion 18a is engaged with the rear end of the motor shaft 13. The radially outer portion of the first support member 18 extends in the axial direction of the motor shaft 13 in a manner away from the motor 10. In addition, an annular rotating disk 15A for the primary encoder 15 is provided on the rear end surface of the portion extending in the axial direction. In other words, the rotating disk 15A is supported by a part of the first support member 18.

[0034] Furthermore, a flange 10b is provided at the rear end of the housing 10a of the actuator 5a. And a cylindrical extension member 41 is mounted on the flange 10b. The rear end surface of the extension member 41 extends radially inward. Furthermore, a second support member 28 is mounted on the inner circumferential surface of the portion extending radially inward by means of a bearing 29. The inner diameter of the second support member 28 is substantially equal to the inner diameter of the hollow portion 22. In addition, a substrate 42 having detection portions 15B and 25B is mounted on the inner circumferential surface of the extension member 41.

[0035] The second support member 28 extends from the rear end of the actuator 5a toward the speed reducer 20, and the front end of the portion extending toward the speed reducer 20 extends radially outward. In addition, an annular rotating disk 25A for the secondary encoder 25 is provided on the rear end surface of the portion extending radially outward. In other words, the rotating disk 25A is supported by a portion of the second support member 28.

[0036] Due to such a structure, the rotating disk 15A of the primary encoder 15 and the rotating disk 25A of the secondary encoder 25 are arranged concentrically with each other at a predetermined gap. In addition, the rotating disk 15A and the rotating disk 25A can also be arranged concentrically with each other using other structures, and even such structures are included in the scope of the present disclosure.

[0037] in addition, Figure 5 is an axial cross-sectional view of the actuator 5' in the prior art. Figure 5 In the embodiment, a flange 23b extending radially outward is provided at the front end of the extension portion 23a. Figure 5 As can be seen, the flange 23b is engaged with the recess formed in the second support member 28'. Furthermore, a plurality of screws 35 parallel to the axial direction penetrate the second support member 28' and the flange 23b to fix them to each other.

[0038] In such a structure, in order to ensure the arrangement space of the screw 35, the rotating disk 25A and the rotating disk 15A need to be moved radially outward by an amount corresponding to the size of the screw 35. In other words, the rotating disks 25A and 15A are enlarged in accordance with the screw 35. Therefore, in order to fix the rotating disk 25A of the secondary encoder 25 to the output shaft 23 of the speed reducer 20, a relatively large space is required. Therefore, in the prior art, there is a problem that the actuator 5' is enlarged.

[0039] In contrast, Figure 1A In the first embodiment shown, the extension 23a (output shaft 23) of the speed reducer 20 and the rotating disk 25A are connected to each other by the first connection portion 31. Strictly speaking, the extension 23a of the speed reducer 20 and the second support member 28 supporting the rotating disk 25A are connected to each other by the first connection portion 31. In addition, it can also be interpreted that the second support member 28 is a part of the first connection portion 31.

[0040] The first coupling portion 31 plays a role in making the part 6a of the actuator 5a including the rotating disk 25A of the secondary encoder 25 slide in the axial direction of the actuator 5a and couple with the output shaft 23. The first coupling portion 31 is configured so as not to make the part 6a of the actuator 5a move in the circumferential direction and radial direction of the actuator 5a.

[0041] Figure 1BFIG. 1 is a partial exploded view of the actuator in the first embodiment. Figure 1B As shown, the unit 6a as a part of the actuator 5a includes the extension member 41, the bearing 29, the second support member 28, the base plate 42 having the detection part 15B and the detection part 25B, and the rotating disk 25A. The unit 6a is configured to be able to move integrally.

[0042] When the unit 6a is slid toward the output shaft 23 in the axial direction of the actuator 5a, the second support member 28 of the unit 6a is coupled to the output shaft 23 by the first coupling portion 31. Thus, the unit 6a does not move in the circumferential and radial directions of the actuator 5a. In addition, the extension member 41 is separately fixed to the flange 10b of the housing 10a by screws or the like.

[0043] The typical first coupling portion 31 is a combination of a spline and a groove. That is, a plurality of splines are formed on one of the outer circumferential surface of the output shaft 23 and the inner circumferential surface of the second support member 28, and a plurality of grooves engaging with the plurality of splines are formed on the other of the outer circumferential surface of the output shaft 23 and the inner circumferential surface of the second support member 28. The spline and the groove have a predetermined length in the axial direction of the actuator 5a. Alternatively, the first coupling portion 31 may be a combination of a key and a keyway formed in a manner extending in the axial direction of the actuator 5a.

[0044] Figure 1C It is a diagram showing a modification example of the first embodiment. Figure 1C The first coupling portion 31 in the embodiment includes a cross coupling. In this case, a first hub 31a is provided on the circumferential surface of the output shaft 23, and a second hub 31b is formed on the end surface of the second support member 28 in a manner opposite to the first hub 31a. Grooves orthogonal to each other are pre-formed in the first hub 31a and the second hub 31b. The groove is provided to extend at least partially in the diameter direction of the actuator 5a. In addition, the first hub 31a and the second hub 31b are provided to have a hollow portion extending in the axial direction of the actuator 5a.

[0045] Furthermore, an annular insert 31c having a hollow portion is disposed between the first hub 31a and the second hub 31b, and the insert 31c is engaged with the first hub 31a and the second hub 31b. A protrusion extending at least partially along the diameter direction of the actuator 5a is provided on one surface of the insert 31c, and a protrusion extending in a direction orthogonal to the protrusion is provided on the other surface of the insert 31c.

[0046] By using an Oldham coupling including the first hub 31a, the second hub 31b and the insert 31c, the second support member 28 of the unit 6a and the output shaft 23 are connected in the same manner as in the above-mentioned structure, and the unit 6a does not move in the circumferential direction and radial direction of the actuator 5a.

[0047] Furthermore, the first coupling portion 31 may also have a structure including the aforementioned spline. Furthermore, the first coupling portion 31 may also have another structure that allows the part 6a of the actuator 5a including the rotating disk 25A of the secondary encoder 25 to slide along the axial direction of the actuator 5a and couple with the output shaft 23.

[0048] When such a first coupling portion 31 (spline or cross coupling) is used, there is no need to insert the screw 35, so there is no need to enlarge the first support member 18 and the second support member 28 in the radial direction. Therefore, compared with the prior art, the rotating disks 25A and 15A can be arranged on the inner side in the radial direction. Furthermore, the flange 23b can also be removed from the output shaft 23. Thus, in the first embodiment, an actuator that can achieve space saving can be provided.

[0049] As mentioned above Figure 5 In the prior art shown, the second support member 28' is fixed to the flange 23b of the output shaft 23 using screws 35. Figure 5 In the structure shown, the second support member 28' needs to be fixed to the flange 23b by the screw 35, taking into account the total tolerance when the force sensor S, the speed reducer 20, the motor 10 and the electromagnetic brake B are combined. At this time, it is necessary to further consider the gap between the rotating disk 25A supported by the second support member 28' and the detection unit 25B arranged on the substrate 42, and the gap between the rotating disk 15A supported by the first support member 18 and the detection unit 15B arranged on the substrate 42. Such positioning work is relatively complicated, so it is difficult to manufacture a high-precision actuator 5' in the prior art.

[0050] In contrast, in the first embodiment, the rotating disk 25A is included in the unit 6a, and the position of the rotating disk 25A in the unit 6a is uniquely determined. In the first embodiment, since the unit 6a is slid only in the axial direction and combined with the output shaft 23 using the first coupling portion 31, the rotating disk 25A can be easily configured in an appropriate position. Therefore, the aforementioned gap can be managed with high precision after the unit 6a is assembled. As a result, a high-precision actuator 5a can be provided. Based on the same reason, it can be known that when the first coupling portion 31 is used, the unit 6a can be easily disassembled from the actuator 5a.

[0051] Figure 2A It is an axial cross-sectional view of the actuator in the second embodiment of the present disclosure. Figure 1A The first embodiment shown is Figure 2AThe difference between the second embodiment shown is that a bearing 19 is disposed between the first support member 18 and the extension member 41, and the second coupling portion 32 couples the protrusion 18a of the first support member 18 and the motor shaft 13. In addition, it can also be interpreted that the first support member 18 is a part of the second coupling portion 32.

[0052] The second coupling portion 32 plays a role in sliding the part 6b of the actuator 5b including the rotating disks 25A and 15A in the axial direction of the actuator 5b and coupling with the motor shaft 13. The second coupling portion 32 is configured so as not to move the part 6b of the actuator 5b in the circumferential and radial directions of the actuator 5b.

[0053] Figure 2B FIG. 1 is a partial exploded view of the actuator in the second embodiment. Figure 2B As shown, the unit 6b as a part of the actuator 5b includes the extension member 41, the bearing 29, the second support member 28, the substrate 42 having the detection part 15B and the detection part 25B, the rotating disk 25A, the first support member 18, the rotating disk 15A and the bearing 19. The unit 6b is configured to be able to move integrally.

[0054] When the unit 6b is slid toward the output shaft 23 and the motor shaft 13 in the axial direction of the actuator 5b, the second support member 28 of the unit 6b is coupled to the output shaft 23 by the first coupling portion 31, and the first support member 18 of the unit 6b is coupled to the motor shaft 13 by the second coupling portion 32. Thus, the unit 6b does not move in the circumferential direction and radial direction of the actuator 5b. In addition, the extension member 41 is separately fixed to the flange 10b of the housing 10a by screws or the like.

[0055] The second coupling portion 32 is typically a combination of a spline and a groove. That is, a plurality of splines are formed on one of the outer circumferential surface of the motor shaft 13 and the inner circumferential surface of the protrusion 18a of the first support member 18, and a plurality of grooves engaging with the plurality of splines are formed on the other of the outer circumferential surface of the motor shaft 13 and the inner circumferential surface of the protrusion 18a of the first support member 18. The spline and the groove have a predetermined length in the axial direction of the actuator 5a.

[0056] Alternatively, the second coupling portion 32 may be a combination of a key and a keyway formed in a manner extending in the axial direction of the actuator 5a. For this purpose, the protrusion 18a of the first supporting member 18 preferably has a predetermined length in the axial direction of the actuator 5b. Figure 1C The structure shown is a crosshead coupling of the same structure.

[0057] Figure 2C It is a diagram showing a modification example of the second embodiment. Figure 2CThe second coupling portion 32 in the embodiment includes a cross-head coupling. In this case, the first supporting member 18 is divided into two parts: a motor side portion and an encoder side portion including a rotating disk 15A. The motor side portion may also be integral with the motor shaft 13. Furthermore, a first hub 32a is provided on the end face of the motor side portion, and a second hub 32b is formed on the end face of the encoder side portion in a manner opposite to the first hub 32a. Mutually orthogonal grooves are pre-formed in the first hub 32a and the second hub 32b. The groove is provided to extend at least partially in the diameter direction of the actuator 5b. In addition, the first hub 32a and the second hub 32b are provided to have a hollow portion extending in the axial direction of the actuator 5a. Furthermore, an annular insert 32c having a hollow portion is arranged between the first hub 32a and the second hub 32b, and the insert 32c is engaged with the first hub 32a and the second hub 32b. A protrusion extending at least partially in the radial direction of the actuator 5a is provided on one surface of the insert 32c, and a protrusion extending in a direction orthogonal to the protrusion is provided on the other surface of the insert 32c.

[0058] In such a case, it is also possible to provide an actuator that can achieve space saving similarly to the above-mentioned actuator.

[0059] Furthermore, in the second embodiment, the rotating disks 15A and 25A are included in the unit 6b, and the positions of the rotating disks 15A and 25A in the unit 6b are uniquely determined. In the second embodiment, since the unit 6b is slid only in the axial direction and is combined with the output shaft 23 by the first combining portion 31, and is combined with the motor shaft 13 by the second combining portion 32, the rotating disks 15A and 25A can be easily arranged in appropriate positions. Therefore, the aforementioned gap management after assembling the unit 6b can be further performed with high precision. As a result, a more precise actuator 5b can be provided. Based on the same reason, it can be known that when the first combining portion 31 and the second combining portion 32 are used, the unit 6b can be easily disassembled from the actuator 5b.

[0060] Figure 3A It is an axial cross-sectional view of an actuator in a third embodiment of the present disclosure. Figure 3A The third embodiment shown is Figure 2A The second embodiment shown is different in that the second support member 28 is connected to the first support member 18 via a bearing 29 ′, and the extension member 41 does not include a portion extending in the radial direction but is cylindrical.

[0061] Figure 3B FIG. 1 is a partial exploded view of the actuator in the third embodiment. Figure 3BAs shown, the unit 6c as a part of the actuator 5c includes the extension member 41, the bearing 29', the second support member 28, the base plate 42 having the detection part 15B and the detection part 25B, the rotating disk 25A, the first support member 18, the rotating disk 15A and the bearing 19. The unit 6c is configured to be able to move integrally.

[0062] It is known that the third embodiment can also obtain substantially the same effect as the second embodiment. Furthermore, in the third embodiment, since the second supporting member 28 is not connected to the extension member 41, the extension member 41 does not need to include a portion extending in the radial direction. Therefore, a relatively large space can be ensured on the rear end side of the actuator 5c. It is known that: in the case where a plurality of line bodies (not shown) pass through the hollow portion 22, the wiring of the plurality of line bodies on the rear end side of the actuator 5c becomes easy.

[0063] Figure 4 It is an axial cross-sectional view of an actuator in another embodiment. Figure 4 The actuator 5d shown mainly includes: a motor 10, which is composed of a stator 11 and a rotor 12; a speed reducer 20, which is connected to the motor 10; and an encoder E. That is, the actuator 5d does not include a force sensor S and an electromagnetic brake B. In addition, the extension member 41 is mounted on the stator 11. It can be seen that in such a case, the actuator 5d can be further miniaturized. In addition, it is assumed that even if the aforementioned actuators 5a to 5c do not include a force sensor S and / or an electromagnetic brake B, it is also included in the scope of the present disclosure.

[0064] As an effect of at least one of the embodiments described above, since the output shaft of the speed reducer and the rotating disk of the secondary encoder are coupled to each other by the first coupling portion, space saving can be achieved.

[0065] The embodiments of the present disclosure are described in detail, but the present disclosure is not limited to the above-mentioned embodiments. These embodiments can be variously added, replaced, changed, partially deleted, etc. without departing from the scope of the gist of the invention, or without departing from the idea and purpose of the present invention derived from the contents recorded in the claims and their equivalents. For example, in the above-mentioned embodiments, the order of each action and the order of each process are shown as an example and are not limited to the above-mentioned order. In addition, the same is true for the case where numerical values ​​or formulas are used in the description of the above-mentioned embodiments. Furthermore, the case where several of the above-mentioned embodiments are appropriately combined is included in the scope of the present disclosure.

[0066] The following supplementary notes are further disclosed with respect to the above-mentioned embodiment and modified examples.

[0067] (Note 1)

[0068] An actuator (5a-5d), wherein:

[0069] The actuator (5a-5d) comprises:

[0070] Electric motor (10);

[0071] A reducer (20) connected to the motor (10);

[0072] a primary encoder (15) that detects the position of a motor shaft (13) of the motor (10); and

[0073] a secondary encoder (25) for detecting the position of an output shaft (23) of the reducer (20),

[0074] The rotating disk (25A) of the secondary encoder (25) is arranged concentrically with respect to the rotating disk (15A) of the primary encoder (15),

[0075] The actuator (5a to 5d) includes a first coupling portion (31) for coupling the output shaft (23) of the speed reducer (20) and the rotating disk (25A) of the secondary encoder (25) to each other.

[0076] (Note 2)

[0077] Based on the actuator (5a~5d) recorded in Appendix 1, the first coupling portion (31) causes a part (6a) of the actuator (5a~5d) including the rotating disk (25A) of the secondary encoder (25) to slide along the axial direction of the actuator (5a~5d) and couple with the output shaft.

[0078] (Note 3)

[0079] In the actuator (5a-5d) described in Supplementary Note 1 or Supplementary Note 2, the first coupling portion (31) includes a spline or a crosshead coupling.

[0080] (Note 4)

[0081] The actuator (5a-5d) according to any one of Appendixes 1-3 further comprises a second coupling portion (32) for coupling the motor shaft (13) of the motor (10) and the rotating disk (15A) of the primary encoder (15) to each other.

[0082] (Note 5)

[0083] Based on the actuator (5a~5d) recorded in Note 4, the second coupling portion (32) causes a part (6b) of the actuator (5a~5d) including the rotating disk (15A) of the primary encoder (15) to slide along the axial direction of the actuator (5a~5d) and couple with the motor shaft (13).

[0084] (Note 6)

[0085] In the actuator (5a-5d) described in Supplement 4 or Supplement 5, the second coupling portion (32) includes a spline or a crosshead coupling.

[0086] (Note 7)

[0087] In the actuator (5a-5d) according to any one of Supplementary Notes 1-6, a bearing (29') is arranged between the rotating disk (25A) of the secondary encoder (25) and components including the rotating disk (15A) of the primary encoder (15).

[0088] Description of Reference Numerals

[0089] 5a~5d, actuator; 6a, 6b, unit; 10, motor; 10a, housing; 10b, flange; 11, stator; 12, rotor; 13, motor shaft; 15, primary encoder; 15A, rotating disk; 15B, detection part; 18, first supporting member; 18a, protrusion; 20, reducer; 23, output part; 23a, extension part; 25A, rotating disk; 25B, detection part; 28, second supporting member; 19, 29, 29', bearing; 31, first coupling part; 31a, first hub; 31b, second hub; 31c, insert; 32, second coupling part; 41, extension member; 42, substrate; B, electromagnetic brake; E, encoder; S, force sensor.

Claims

1. An actuator, wherein: The actuator has: Electric motor; A reducer connected to the motor; a primary encoder that detects the position of a motor shaft of the motor; and The secondary encoder detects the position of the output shaft of the reducer, The rotating disk of the secondary encoder is arranged concentrically with respect to the rotating disk of the primary encoder, The actuator includes a first coupling portion that couples the output shaft of the speed reducer and the rotating disk of the secondary encoder to each other.

2. The actuator according to claim 1, wherein: The first coupling portion allows a portion of the actuator including the rotating disk of the secondary encoder to slide along the axial direction of the actuator and to couple with the output shaft.

3. The actuator according to claim 2, wherein: The first coupling portion includes a spline or a crosshead coupling.

4. The actuator according to claim 1, wherein: The actuator further includes a second coupling portion coupling the motor shaft of the motor and the rotating disk of the primary encoder to each other.

5. The actuator according to claim 4, wherein: The second coupling portion allows a portion of the actuator including the rotating disk of the primary encoder to slide along the axial direction of the actuator and to couple with the motor shaft.

6. The actuator according to claim 5, wherein: The second coupling portion includes a spline or a crosshead coupling.

7. The actuator according to claim 1, wherein: A bearing is arranged between the rotating disk of the secondary encoder and components including the rotating disk of the primary encoder.

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