CN114641381B

CN114641381B - Drive device

Info

Publication number: CN114641381B
Application number: CN202080076995.3A
Authority: CN
Inventors: 田村光扩
Original assignee: Sumitomo Heavy Industries Ltd
Current assignee: Sumitomo Heavy Industries Ltd
Priority date: 2019-11-11
Filing date: 2020-09-18
Publication date: 2024-12-10
Anticipated expiration: 2040-09-18
Also published as: DE112020005575T5; CN114641381A; JP7321894B2; WO2021095362A1; JP2021076191A

Abstract

The invention provides a driving device capable of detecting torque output from the driving device with high accuracy and suppressing the assembly cost for detecting the torque to be low. The drive device (1) is provided with input members (13, 15 a) for inputting torque, a reduction mechanism (15), an output member (16) for transmitting rotation after reduction, an input-side rotation detector (18) for detecting rotation of the input member, and an output-side rotation detector (19) for detecting rotation of the output member. The Young's modulus of the parts (15 d, 15 e) with the smallest Young's modulus in the speed reducing mechanism (15) and the output member (16) is smaller than the Young's modulus of the parts with the smallest Young's modulus in the input members (13, 15 a), and the resolution of the output side rotation detector (19) is lower than the resolution of the input side rotation detector (18).

Description

Driving device

Technical Field

The present invention relates to a driving device.

Background

Patent document 1 discloses a robot device having a joint rotationally driven via a rotary motor and a speed reducer. The robot device of patent document 1 includes an input-side encoder that generates a pulse signal every minute rotation of a rotation motor, a rectangular wave generating unit that generates a pulse signal according to a rotation angle of a joint, an output-side encoder that generates a pulse signal every minute rotation of a joint on an output side of a speed reducer, and a control unit that calculates a torsion angle of the joint from the pulse signals.

Technical literature of the prior art

Patent literature

Patent document 1 Japanese patent application laid-open No. 2014-65097

Disclosure of Invention

Technical problem to be solved by the invention

In a driving device that amplifies and outputs an input torque via a speed reducer, strain is generated between an input member and an output member according to the torque. If a strain sensor is used for strain detection or a high-resolution encoder is used, the assembly cost of the device increases.

The present invention aims to provide a driving device capable of suppressing the assembly cost for detecting the torque of the driving device to be low.

Means for solving the technical problems

The drive device according to the present invention includes an input member for inputting torque, a speed reduction mechanism for reducing rotation of the input member, and an output member for transmitting rotation reduced by the speed reduction mechanism, and further includes:

an input-side rotation detector for detecting rotation of the input member, and

An output-side rotation detector for detecting rotation of the output member,

When a portion of the input member having the smallest young's modulus from the torque input portion to the reduction mechanism is referred to as an input-side minimum rigidity portion, and a portion of the reduction mechanism and the output member having the smallest young's modulus in a region in which the torque amplified by the reduction mechanism is transmitted is referred to as an output-side minimum rigidity portion,

The young's modulus of the output side minimum stiffness region is smaller than the young's modulus of the input side minimum stiffness region,

The resolution of the output side rotation detector is lower than the resolution of the input side rotation detector.

Another drive device according to the present invention includes an input member for inputting torque, a speed reduction mechanism for reducing rotation of the input member, and an output member for transmitting rotation reduced by the speed reduction mechanism, and further includes:

an input-side rotation detector for detecting rotation of the input member, and

An output-side rotation detector for detecting rotation of the output member,

The young's modulus of the input side minimum stiffness region is smaller than the young's modulus of the output side minimum stiffness region,

The resolution of the input side rotation detector is lower than the resolution of the output side rotation detector.

Effects of the invention

According to the present invention, the cost of the component for detecting the torque of the drive device can be suppressed to be low.

Drawings

Fig. 1 is a cross-sectional view showing a driving device according to an embodiment of the present invention.

Fig. 2 is a diagram showing a control structure of the driving device according to the embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a cross-sectional view showing a driving device according to an embodiment of the present invention. The application of the driving device 1 of the present embodiment is not particularly limited, but can be used as, for example, a joint driving device of a cooperative robot that cooperates with a person to perform work. Hereinafter, the direction along the central axis O1 is referred to as the axial direction, the radial direction around the central axis O1 is referred to as the radial direction, and the rotational direction around the central axis O1 is referred to as the circumferential direction. The central axis O1 is the central axis of the shaft portion 16c of the output member 16 and the rotor shaft 13. The side (left side in fig. 1) of the output member 16 in the axial direction of the central axis O1, which is connected to the target member 202, is referred to as an output side, and the opposite side (right side in fig. 1) is referred to as an output opposite side or an input side.

The driving device 1 of the present embodiment includes a frame portion 11 connected to a support member 201 outside the device, an electric motor 12 partially supported by the frame portion 11, a rotor shaft 13 to which torque is input from the electric motor 12, a braking mechanism 14 partially supported by the frame portion 11 and capable of applying a braking force to the rotor shaft 13, a speed reduction mechanism 15 for reducing the rotational movement of the rotor shaft 13, an output member 16 for outputting the rotational movement reduced by the speed reduction mechanism 15 to the outside of the device, a circuit board (driver) 17 on which a driving circuit of the electric motor 12 is mounted, an input-side rotation detector 18 for detecting the rotation of the rotor shaft 13, and an output-side rotation detector 19 for detecting the rotation of the output member 16. A speed reduction mechanism 15, an electric motor 12, a brake mechanism 14, a rotation detection unit (an input side rotation detector 18 and an output side rotation detector 19), and a circuit board 17 are arranged in this order from the output side to the opposite side. The rotor shaft 13 and the oscillating body 15a of the reduction mechanism 15 correspond to an example of an input member according to the present invention.

The frame 11 includes hollow cylindrical or annular members 11a to 11g connected to each other, and is supported by a support member 201 outside the apparatus. The members 11f, 11g may be coupled to the member 11e via members of the reduction mechanism 15. In the specific example of fig. 1, the support member 201 is fastened to the member 11f via bolts, and the 1 st internal gear 15d is fastened together between the support member 201 and the member 11 f. More specifically, the member 11a radially covers the inner structure of the driving device 1 on the opposite side of the output. A circuit board 17, an input-side rotation detector 18, and an output-side rotation detector 19 may be disposed at a portion covered with the member 11 a. The member 11b covers the internal structure of the drive device 1 from the axial direction on the opposite output side. The member 11b has a through hole penetrating in the axial direction, and the through hole of the member 11b is arranged to communicate with the through hole of the shaft portion 16 c. The outer ring of the bearing 21 is fitted to the member 11b, and the member 11b rotatably supports the shaft portion 16c via the bearing 21. The member 11b is coupled to the member 11a by bolts or the like. The member 11c is coupled to the member 11a by bolts or the like, and covers the internal structure of the drive device 1 from the radial direction on the output side of the arrangement portion of the member 11 a. A braking mechanism 14 may be disposed at a portion covered with the member 11 c. The member 11d is coupled to the member 11c by bolts or the like, and covers the internal structure of the drive device 1 from the radial direction on the output side of the arrangement portion of the member 11 c. An electric motor 12 may be disposed at a portion covered with the member 11 d. A part (stator 12 a) of the electric motor 12 is fixed to the frame 11 (e.g., the member 11 d). The member 11e is disposed on the output side of the member 11d, and is coupled to the member 11d by bolts or the like. An outer ring of the bearing 23 is fitted to the member 11e, and the member 11e rotatably supports the shaft portion of the oscillating body 15a via the bearing 23. The member 11e is also coupled to the 1 st internal gear 15d of the reduction mechanism 15 by bolts or the like. The member 11f is disposed on the output side of the reduction mechanism 15, and is coupled to the 1 st internal gear 15d of the reduction mechanism 15 by a bolt or the like. The 1 st internal gear 15d has an extension portion extending from the opposite output side of the reduction mechanism 15 where the teeth portion of the 1 st internal gear 15d are arranged toward the output side so as to cover the radially outer side of the 2 nd internal gear 15e, and the extension portion is coupled to the member 11 f. The member 11g is coupled to the member 11f and the 1 st internal gear 15d by bolts or the like, and covers the internal structure of the output side of the drive device 1 from the radial direction. The member 11f is fastened together with the 2 nd internal gear 15e between the member 11g and the same. An outer ring of the bearing 22 is fitted to the member 11g, and the member 11g rotatably supports the output member 16 via the bearing 22. The member 11g has an extension portion extending to the output side from the bearing 22, and a seal of dust or a lubricant is fitted in the extension portion. The structure of the frame 11 is not limited to the specific example described above.

The output member 16 includes a member 16a, a member 16b, and a shaft portion 16c coupled to each other, and is rotatably supported by the frame 11 via bearings 21 and 22. The output member 16 has a hollow structure (hollow cylindrical shape). A portion of the output member 16 is exposed to the output side, and the exposed portion is coupled to the subject member 202. More specifically, the shaft portion 16c penetrates the reduction mechanism 15 and extends to the side on which the rotor shaft 13 is located. A rotation portion 19a of the output-side rotation detector 19 is fixed to the shaft portion 16c on the opposite output side from the reduction mechanism 15. The member 16a is disposed on the output side of the driving device 1, and is fitted with one end of the shaft portion 16 c. An inner race of the bearing 22 is fitted to the member 16 a. The member 16a has an extension portion extending further to the output side than the bearing 22, and the extension portion is located on the inner peripheral side of the seal. For example, a gasket is fitted to the extension portion to fill a gap on the inner peripheral side of the seal. The member 16b is disposed on the opposite side of the output of the member 16a and on the output side of the reduction mechanism 15, and a part of the output side of the member 16b is coupled to the member 16a by a bolt or the like, and a part of the opposite side of the output of the member 16b is coupled to the 2 nd internal gear 15e of the reduction mechanism 15 by a bolt or the like. An outer ring of the bearing 24 is fitted to the member 16b, and the member 16b rotatably supports the oscillating body 15a via the bearing 24. The member 16b is coupled to the target member 202 by bolts or the like. The part 16a is fastened together between the part 16b and the subject part 202. The structure of the output member 16 is not limited to the specific example described above.

The electric motor 12 includes a stator 12a and a hollow cylindrical rotor 12b. In the present embodiment, the rotor 12b is constituted by a permanent magnet.

The rotor shaft 13 has a hollow structure, and is fitted to the shaft portion 16c of the output member 16 so as to be spaced apart from the shaft portion 16c of the output member 16. The rotor shaft 13 is coupled to the rotor 12b of the electric motor 12. The electric motor 12 and the rotor shaft 13 are disposed on the opposite side of the output of the reduction mechanism 15. A rotation portion 18a of the input side rotation detector 18 is fixed to the opposite side of the output of the rotor shaft 13.

The speed reduction mechanism 15 is a cylindrical flex-meshing gear mechanism, and includes a vibrator 15a, a vibrator bearing 15b, an external gear 15c that is deformed by rotation of the vibrator 15a, and a1 st internal gear 15d and a 2 nd internal gear 15e that mesh with the external gear 15 c. The oscillating body 15a has a hollow structure, and is fitted to the shaft portion 16c of the output member 16 so as to be spaced apart from the shaft portion 16c of the output member 16. The oscillating body 15a is coupled (e.g., spline-coupled) to the rotor shaft 13 so as to integrally rotate with the rotor shaft 13. The rotor shaft 13 and the oscillating body 15a constitute an input member. The shaft portion of the oscillating body 15a is rotatably supported by the frame 11 and the output member 16 via bearings 23 and 24. In the oscillating body 15a, the cross section of the shaft portion perpendicular to the axial direction has a circular shape centered on the central axis O1, and the cross section of the portion in contact with the oscillating body bearing 15b perpendicular to the axial direction has an elliptical shape, for example. The external gear 15c has flexibility. The 1 st internal gear 15d is coupled to the frame 11 and meshes with a range on the opposite side of the output in the axial direction of the external gear 15 c. The 2 nd internal gear 15e is coupled to the output member 16, and meshes with the range of the output side in the axial direction of the external gear 15 c.

In the speed reduction mechanism 15, the rotational motion is input to the oscillating body 15a, and the reduced rotational motion is output to the 2 nd internal gear 15e. In the speed reduction mechanism 15, the torque input to the oscillating body 15a is amplified, the amplified torque is transmitted to the 2 nd internal gear 15e, and the reaction force of the amplified torque is transmitted to the 1 st internal gear 15d. That is, the amplified torque is transmitted to the 1 st internal gear 15d and the 2 nd internal gear 15e.

The 1 st internal gear 15d and the 2 nd internal gear 15e are made of a resin material. As the resin material, for example, a simple resin such as a synthetic resin, a Fiber-reinforced resin such as FRP (Fiber-Reinforced Plastic: fiber-reinforced plastic), CFRP (Carbon Fiber Reinforced Plastic: carbon Fiber-reinforced plastic), or the like can be used. However, the resin material is not limited to this, and various resin materials such as paper phenol resin and cloth phenol resin may be used.

The input-side rotation detector 18 includes a rotation portion 18a that rotates integrally with the rotor shaft 13, and a detection portion 18b that is disposed in the vicinity of the rotation portion 18a and detects the rotation amount of the rotation portion 18 a. The output-side rotation detector 19 includes a rotation portion 19a that rotates integrally with the output member 16, and a detection portion 19b that is disposed in the vicinity of the rotation portion 19a and detects the rotation amount of the rotation portion 19 a. The input-side rotation detector 18 and the output-side rotation detector 19 are rotary encoders that output, for example, a displacement of rotation of a rotating unit as a digital signal, but a resolver (resolver) that outputs an analog signal may be used, or other rotation detectors may be used. The rotary encoder may have an optical detection unit or a magnetic detection unit. The input-side rotation detector 18 and the output-side rotation detector 19 may be different types of detectors.

The resolution of the input side rotation detector 18 is higher than the resolution of the output side rotation detector 19. For example, the resolution of the input-side rotation detector 18 is 16 bits of one rotation, whereas the resolution of the output-side rotation detector 19 is 8 bits of one rotation.

In the input-side rotation detector 18 and the output-side rotation detector 19, two detection units 18b and 19b are mounted on the circuit board 17, and the two rotation units 18a and 19a are disposed so as to face the two detection units 18b and 19b from the output side of the circuit board 17. More specifically, the installation position of the rotating portion 19a on the output member 16 and the installation position of the rotating portion 18a on the rotor shaft 13 are located at substantially the same position in the axial direction, and similarly, the two detecting portions 18b and 19b are also arranged at substantially the same position in the axial direction. That is, the rotating portion 18a and the rotating portion 19a are disposed at positions overlapping each other when viewed in the radial direction, and the rotating portion 18a is disposed radially outward. The detection portions 18b and 19b are disposed at positions overlapping each other when viewed in the radial direction, and the detection portions 18b are disposed radially outward.

< Description of operation >

When the electric motor 12 is driven to rotate the rotor shaft 13 and the oscillating body 15a, the motion of the oscillating body 15a is transmitted to the external gear 15c. At this time, the shape of the external gear 15c is limited to conform to the shape of the outer peripheral surface of the starting body 15a, and it flexes into an elliptical shape having a major axis portion and a minor axis portion as viewed from the axial direction. Further, the long shaft portion of the external gear 15c meshes with the fixed 1 st internal gear 15 d. Therefore, the external gear 15c does not rotate at the same rotation speed as the starting body 15a, but the starting body 15a rotates relatively inside the external gear 15c. Then, with this relative rotation, the external gear 15c is deformed so as to move in the circumferential direction in the major axis position and the minor axis position. The deformation period is proportional to the rotation period of the oscillating body 15 a. When the external gear 15c is deformed by bending, the long axis position thereof moves, and the meshing position of the external gear 15c and the 1 st internal gear 15d changes in the rotational direction. Here, it is assumed that the number of teeth of the external gear 15c is 100 and the number of teeth of the 1 st internal gear 15d is 102. As a result, the external gear 15c rotates (rotates) by sequentially shifting the meshing teeth of the 1 st internal gear 15d from the external gear 15c for each rotation of the meshing position. If the number of teeth is the above number, the rotational motion of the oscillating body 15a is decelerated at a reduction ratio of 100:2 and then transmitted to the external gear 15c. On the other hand, the external gear 15c is also meshed with the 2 nd internal gear 15e, and therefore the meshing position of the external gear 15c with the 2 nd internal gear 15e is also changed in the rotational direction by the rotation of the oscillating body 15 a. Here, if the number of teeth of the 2 nd internal gear 15e is equal to the number of teeth of the external gear 15c, the external gear 15c and the 2 nd internal gear 15e do not rotate relatively, and the rotational motion of the external gear 15c is transmitted to the 2 nd internal gear 15e at a reduction ratio of 1:1. Thus, the rotational motion of the oscillating body 15a is decelerated at a reduction ratio of 100:2, transmitted to the 2 nd internal gear 15e, and output from the 2 nd internal gear 15e to the target member 202 via the output member 16.

In the transmission of the above-described rotational motion, the rotational position of the rotor shaft 13 is detected by the input-side rotation detector 18, and the rotational position of the output member 16 is detected by the output-side rotation detector 19.

< Transmission and detection of Torque >

Here, a case will be described in which torque and rotational motion are transmitted from the driving device 1 to the target member 202 coupled to the output member 16. At this time, the torque and the rotational motion output from the electric motor 12 are transmitted from the rotor shaft 13 to the speed reduction mechanism 15, the torque is amplified by the speed reduction mechanism 15, and the rotational motion is reduced. The amplified torque and the decelerated rotational motion are then transmitted from the deceleration mechanism 15 to the target component 202 via the output component 16.

The torque transmission before amplification is performed in a section from the torque input portion (the connection portion of the rotor 12 b) to the connection portion with the vibration starting body 15a in the rotor shaft 13 and in a section from the connection portion with the rotor shaft 13 to the contact portion with the vibration starting body bearing 15b in the vibration starting body 15 a. The vibration generating body 15a and the above-described section in the rotor shaft 13 are each made of metal such as steel. In these sections, when the region having the smallest young's modulus is referred to as an input-side minimum rigidity region, these sections each correspond to the input-side minimum rigidity region, and the young's modulus corresponds to the young's modulus of the metal. The portion of the rotor shaft 13 on the opposite side of the torque input portion from the speed reduction mechanism is not a portion through which torque is transmitted (passed) before amplification, and therefore the material (young's modulus) thereof is not particularly limited, but in the present embodiment, it is made of metal as in the other portions of the rotor shaft 13.

The portion (section) of the frame 11 from the connection point with the support member 201 to the connection point with the 1 st internal gear 15d, the external gear 15c, the 2 nd internal gear 15e, and the section of the output member 16 from the connection point with the 2 nd internal gear 15e to the connection point with the target member 202 are constituted by a portion that transmits the amplified torque to the support member 201 and receives the torque and a portion that transmits the amplified torque to the target member 202. In the specific example of fig. 1, the torque amplified by the speed reduction mechanism 15 is transmitted from the member 11f of the frame 11 to the members 16b and 16a of the output member 16 through the 1 st internal gear 15d, the external gear 15c, and the 2 nd internal gear 15 e. The 1 st internal gear 15d and the 2 nd internal gear 15e are made of a resin material as described above, and the other portions are made of a metal such as steel. Of these, when the portion having the smallest young's modulus is referred to as the output side minimum rigidity portion, the output side minimum rigidity portion is the 1 st internal gear 15d and the 2 nd internal gear 15e, and the young's modulus thereof corresponds to the young's modulus of the resin material.

In torque transmission, the member is strained by the torque, and therefore the rotational position of the output member 16 is shifted from the output-side reference position. In the ideal structure without strain, the output side reference position indicates the rotational position of the output member 16 corresponding to the rotational positions of the rotor shaft 13 and the oscillating body 15 a. The strain amount can be measured from the displacement of the output member 16 from the output-side reference position. Further, since the torque and the strain amount have a constant relationship, the torque can be detected from the strain amount.

Since only a small torque is applied to the rotor shaft 13, strain in the rotational direction thereof is small, and the amount of strain affects the output side by reducing the amount equivalent to the reduction ratio via the reduction mechanism 15. Therefore, even if the output side is an ideal structure that does not generate strain, it is necessary to detect the amount of strain in the rotational direction of the rotor shaft 13 from the displacement of the output member 16 from the output side reference position, and the resolution of the rotation detection of the output member 16 is extremely high.

Since a large torque is applied to the output-side members (the output member 16, the 1 st internal gear 15d, and the 2 nd internal gear 15 e), the strain in the rotational direction thereof is large, and the magnitude of the strain is directly affected as a shift in the rotational position of the output member 16. Therefore, it is easy to detect the amount of strain in the rotational direction of the output side from the displacement of the output member 16 from the output side reference position.

However, the output side reference position is determined according to the rotational position of the rotor shaft 13, but the rotational amount of the rotor shaft 13 is transmitted to the output side after being reduced by the reduction ratio of the reduction mechanism 15. Therefore, the output-side reference position can be determined more finely with respect to the resolution of rotation detection of the rotor shaft 13. For example, the rotational position of the rotor shaft 13 can be detected every 1 degree, and if the reduction ratio is 1/50, the output side reference position can be determined every 0.02 degree (=1 degree/50). If the output-side reference position can be determined more finely, the offset of the output member 16 from the output-side reference position can be measured with high accuracy. At this time, the resolution of rotation detection on the output side needs to be equivalent to the embossing of the position on the output side. If the resolution of the rotation detection on the output side is lowered, the accuracy of measuring the displacement (strain amount) of the output member 16 from the position on the output side is lowered in response thereto. When the strain amount is small relative to the torque, the error in torque detection increases as the resolution of the measurement of the strain amount decreases.

Therefore, in the present embodiment, the young's modulus of the output side minimum rigidity portion is set lower than that of the input side minimum rigidity portion. As a result, the strain in the rotational direction of the output member 16 increases with respect to the torque, and even if the resolution of the measured strain amount decreases, the detection error of the torque can be suppressed to be low. Further, since the allowable resolution of the measured strain amount can be reduced, the resolution of the output-side rotation detector 19 is set lower than the resolution of the input-side rotation detector 18, and therefore the component cost of the output-side rotation detector 19 is suppressed.

< Calculation Structure of Torque >

As shown in fig. 2, the driving device 1 of the present embodiment further includes an operation unit 31 that calculates a torque output to the target member 202. The arithmetic unit 31 is a microcomputer or the like, and may be mounted on the circuit board 17 or may be provided separately from the circuit board 17.

The calculation unit 31 includes, for example, an I/O33 for inputting each detection value from the input-side rotation detector 18 and the output-side rotation detector 19, a storage unit 34 for storing a data table 34a indicating a relation between a deviation from the output-side reference position and a torque of the rotation position of the output member 16, and a torque calculation unit 32 for obtaining the torque output from the output member 16 to the target member 202. The torque calculation unit 32 may calculate the deviation of the rotational position of the output member 16 from the output reference position based on the detection values of the input-side rotation detector 18 and the output-side rotation detector 19, and compare the calculation result with the data table 34a to obtain the torque. The respective table values in the data table 34a are obtained by measuring the offset by experimental and addition of various torques.

The torque obtained by the calculation unit 31 is output to a higher-level control device, for example, and if it exceeds the limit torque, the device may be stopped or used for detecting data that something (e.g., a person) is accidentally in contact with the target member 202.

As described above, according to the driving device 1 of the present embodiment, the young's modulus of the output side minimum rigidity portion (the 1 st internal gear 15d and the 2 nd internal gear 15 e) is lower than the young's modulus of the input side minimum rigidity portion (the rotor shaft 13 and the vibrator 15 a). Further, the resolution of the output side rotation detector 19 is lower than that of the input side rotation detector 18. Therefore, as described above, the cost of the output-side rotation detector 19 can be reduced, and the torque with small error can be detected from the detection values of the input-side rotation detector 18 and the output-side rotation detector 19.

Further, according to the driving device 1 of the present embodiment, the output side minimum rigidity portion is made of a resin material, and the input side minimum rigidity portion is made of a metal material. According to this structure, it is possible to obtain appropriate rigidity and appropriate flexibility suitable for reducing an error in torque detection while suppressing a decrease in the motion performance of the drive device 1. Further, since the robot has appropriate rigidity and appropriate flexibility, the robot can be suitably applied to a device for moving a joint of a cooperative robot that cooperates with a person to perform work.

Further, the driving device 1 according to the present embodiment includes an operation unit 31 for calculating the torque output to the target member 202 based on the detection values of the input-side rotation detector 18 and the output-side rotation detector 19. Further, the torque output to the target member 202 can be converted into a torque acting on each portion between the output member 16 and the input member (the rotor shaft 13 and the oscillating body 15 a), and therefore, the operation unit 31 can be regarded as a portion for calculating the torque acting on each portion. According to this type of calculation unit 31, torque can be obtained without using an expensive sensor that directly detects torque, and thus the calculation unit can be used for various kinds of control based on torque.

In the driving device 1 according to the present embodiment, the internal gears (15 d, 15 e) of the reduction mechanism 15 are used as the output side minimum rigidity portions. As long as it is an internal gear, the radial thickness of the gear can be increased without changing the pitch diameter. Therefore, the thickness of the gear can be increased without changing the meshing structure and the size of the gear, and the strength deficiency caused by the reduced rigidity can be easily compensated.

Further, according to the driving device 1 of the present embodiment, the reduction mechanism 15 is a cylindrical flex-mesh gear mechanism, and the 1 st internal gear 15d and the 2 nd internal gear 15e are used as the output side minimum rigidity portions. According to this structure, it is possible to easily realize a structure in which an appropriate amount of offset occurs in the rotational position of the output member 16 according to the torque while suppressing a decrease in the strength of the device due to the provision of the output-side minimum rigidity portion.

Further, according to the driving device 1 of the present embodiment, the output member 16 has the shaft portion 16c, and the shaft portion 16c penetrates the reduction mechanism 15 and extends to the input side of the torque of the input member (the rotor shaft 13 and the oscillating body 15 a). The output-side rotation detector 19 is disposed closer to the input-side rotation detector 18 than the reduction mechanism 15. Therefore, the input-side rotation detector 18 and the output-side rotation detector 19 can be brought close to each other to collect the positions at which the two signals are led out to the outside. Or signal lines for transmitting the respective signals to an arithmetic unit using two signals may be collected. By assembling these components together, the assembly of the electrical components can be intensively performed, and thus the complexity of the assembly process of the driving device 1 can be reduced.

(Modification)

In the above embodiment, the structure is adopted in which the young's modulus of the output side minimum stiffness portion is lower than that of the input side minimum stiffness portion and the resolution of the output side rotation detector 19 is lower than that of the input side rotation detector 18. The driving device of the modification is configured such that the young's modulus of the input side minimum stiffness portion is lower than the young's modulus of the output side minimum stiffness portion and the resolution of the input side rotation detector 18 is lower than the resolution of the output side rotation detector 19. The other components are the same as those of the driving device 1 of the above embodiment. In the driving device according to the modification, for example, the 1 st internal gear 15d and the 2 nd internal gear 15e of the reduction mechanism 15 are made of metal such as steel, and the section for torque transmission in the input member (the rotor shaft 13 and the oscillating body 15 a) may include a resin structure, for example.

In the driving device according to the modification, for example, in the ideal configuration without strain, when the rotational position of the rotor shaft 13 corresponding to the rotational position of the output member 16 is set as the input-side reference position, and torque is obtained from the deviation of the rotational position of the rotor shaft 13 from the input-side reference position, a large strain corresponding to the torque is obtained on the input side than on the output side. Therefore, the resolution of the input-side rotation detector 18 can be reduced, so that cost reduction can be achieved, and torque can be obtained with high accuracy.

The embodiments of the present invention have been described above. The present invention is not limited to the above embodiments. For example, the speed reduction mechanism is not limited to a cylindrical flex-engagement gear mechanism, and various mechanisms such as a so-called cup-shaped or top hat-shaped flex-engagement gear mechanism, a planetary gear mechanism, and an eccentric swing-type speed reduction mechanism may be used. In the above embodiment, the example was described in which the portion with low young's modulus and the portion with high young's modulus are made of resin and the portion with high young's modulus are made of metal, but the material is not particularly limited as long as the relationship between young's modulus can be maintained, and for example, two kinds of metals with different young's moduli may be applied to the portion with low young's modulus and the portion with high young's modulus, respectively. In the embodiment, the 1 st internal gear 15d and the 2 nd internal gear 15e are applied as the output-side minimum rigidity portion, but the output-side minimum rigidity portion may be provided in a section where torque amplified by the reduction mechanism is transmitted, and may be, for example, one of the 1 st internal gear 15d and the 2 nd internal gear 15e, or may be an output member, a frame portion, or a part thereof. In the embodiment, the rotor shaft 13 and the vibration starting body 15a are set as the input-side minimum rigidity portion as a whole, but the input-side minimum rigidity portion may be provided between the torque input portion and the reduction mechanism in the input member, and for example, a portion having a low young's modulus and a portion having a different young's modulus from the rotor shaft 13 and the vibration starting body 15a may be set as the input-side minimum rigidity portion. The brake mechanism 14, the circuit board 17, or both of the drive device 1 according to the embodiment may be omitted, or a mechanism for generating rotational power such as the electric motor 12 may be omitted, and rotational power may be input to the input member from the outside through the motion transmission mechanism instead. The detailed structure shown in the embodiments may be modified as appropriate within the scope of the invention.

Industrial applicability

The present invention can be used for a driving device.

Symbol description

1-Drive device, 11-frame portion, 12-electric motor, 13-rotor shaft (input member), 14-brake mechanism, 15-speed reduction mechanism, 15 a-oscillating body (input member), 15 c-external gear, 15 d-1 st internal gear, 15 e-2 nd internal gear, 16-output member, 16 c-shaft portion, 17-circuit substrate, 18-input side rotation detector, 18 a-rotation portion, 18 b-detection portion, 19-output side rotation detector, 19 a-rotation portion, 19 b-detection portion, 31-operation portion, 32-torque calculation portion, 34 a-data sheet, 201-support member, 202-object member.

Claims

1. A drive device comprising an input member for inputting torque, a speed reduction mechanism for reducing the speed of rotation of the input member, and an output member for transmitting the rotation reduced by the speed reduction mechanism, wherein the drive device further comprises:

an input-side rotation detector for detecting the rotation of the input component; and

an output side rotation detector for detecting the rotation of the output component,

When the portion of the input member where the Young's modulus is the smallest between the torque input portion and the reduction mechanism is referred to as the input-side minimum rigidity portion, and the portion of the reduction mechanism and the output member where the Young's modulus is the smallest in the torque transmission section amplified by the reduction mechanism is referred to as the output-side minimum rigidity portion,

The Young's modulus of the minimum rigidity portion on the output side is smaller than the Young's modulus of the minimum rigidity portion on the input side,

The resolution of the output-side rotation detector is lower than the resolution of the input-side rotation detector.

2. The driving device according to claim 1, characterized in that:

The input side least rigid part is made of metal,

The output side minimum rigidity portion is made of resin.

3. The driving device according to claim 1 or 2, characterized in that:

A calculation unit is further provided for calculating a torque acting on a portion between the input member and the output member based on a detection value of the input-side rotation detector and a detection value of the output-side rotation detector.

4. The driving device according to claim 1 or 2, characterized in that:

The speed reduction mechanism comprises an internal gear and an external gear meshing with the internal gear.

The minimum rigidity portion on the output side is the internal gear.

5. The driving device according to claim 1 or 2, characterized in that:

The speed reduction mechanism is a flexural meshing type gear mechanism including an external gear, a vibrator that flexibly deforms the external gear, and a first internal gear and a second internal gear that mesh with the external gear.

The output-side minimum rigidity portion is the first internal gear and the second internal gear.

6. The driving device according to claim 1 or 2, characterized in that:

The output member penetrates the speed reduction mechanism and extends to the torque input side of the input member.

The output-side rotation detector is provided at a position closer to the input side than the speed reduction mechanism.

7. A drive device comprising an input member for inputting torque, a speed reduction mechanism for reducing the speed of rotation of the input member, and an output member for transmitting the rotation reduced by the speed reduction mechanism, wherein the drive device further comprises:

The Young's modulus of the minimum rigidity portion on the input side is smaller than the Young's modulus of the minimum rigidity portion on the output side,

The resolution of the input-side rotation detector is lower than the resolution of the output-side rotation detector.