Articulated implement

Abstract

The application discloses a joint actuator, which comprises a shell, a motor driving assembly, a planetary transmission assembly, an output planetary carrier and a multi-piece magnetorheological damping assembly. The motor driving assembly comprises a stator coil and a rotor-sun gear assembly, and the rotor-sun gear assembly is provided with a sun gear tooth part fixed with the rotor part and rotating synchronously; the planetary gear is rotatably arranged on the output planetary carrier and is engaged with the sun gear tooth part and a gear ring fixed relative to the shell. The multi-piece magnetorheological damping assembly comprises a magnetizing coil, a magnetorheological working cavity and a plurality of inner disc pieces and a plurality of outer disc pieces arranged alternately, the inner disc pieces are connected with the rotor-sun gear assembly in the circumferential direction and are limited, and the outer disc pieces are fixed relative to the shell. The magnetizing coil generates a magnetic field acting on the magnetorheological medium to adjust the shear resistance between the inner disc pieces and the outer disc pieces, and an adjustable damping is applied to the output planetary carrier through the planetary transmission assembly. The application can realize the integration of joint driving and adjustable damping under a compact structure.

Description

Technical Field

[0001] This invention relates to the field of joint actuator technology. Background Technology

[0002] Robotic joint actuators typically need to perform functions such as active drive, deceleration output, and buffering or braking within a limited installation space. These actuators usually consist of a motor and a reduction gear to form the drive output, with a separate brake or damper. If these additional functional components are connected to the motor or reduction gear as relatively independent modules, additional mounting, connection, and support structures are usually required, which is detrimental to the miniaturization and integration of the joint actuator.

[0003] Magnetorheological media can change their shear resistance under the influence of an external magnetic field, and can be used to form adjustable damping. When applying magnetorheological damping structures to articulated actuators, their arrangement and force transmission relationship with the motor and reduction gear will affect the overall size and damping performance of the articulated actuator. If the magnetorheological damping structure is connected to the articulated drivetrain as a relatively independent module, it usually requires additional housings, connectors, and supports; at the same time, when installation space is limited, the area available for generating shear force is limited, making it difficult to balance structural compactness and damping torque requirements.

[0004] In addition, when robot joints are subjected to impacts or external disturbances, damping structures are required to provide damping effects that are adapted to the joint's motion state.

[0005] Therefore, how to reasonably coordinate the magnetorheological damping structure with the joint drive structure and deceleration structure within a limited installation space, and meet the adjustable damping requirements while reducing independent connections and support components, is a problem that needs to be further solved in the structural design of joint actuators. Summary of the Invention

[0006] Based on the technical problems existing in the background technology, the present invention proposes a joint actuator that can integrate joint drive and adjustable damping in a compact structure.

[0007] The present invention proposes a joint actuator, comprising a housing, a motor drive assembly, a planetary transmission assembly, an output planetary carrier, and a multi-plate magnetorheological damping assembly; The motor drive assembly includes a stator coil and a rotor-sun gear assembly. The stator coil is disposed on the housing. The rotor-sun gear assembly is rotatably disposed relative to the housing. The rotor-sun gear assembly includes a rotor portion and a sun gear tooth portion. The rotor portion and the sun gear tooth portion are fixedly connected and rotate synchronously. The planetary transmission assembly includes planetary gears and a ring gear. The ring gear is fixedly disposed with the housing, and the planetary gears are rotatably disposed on the output planetary carrier and mesh with the sun gear teeth and the ring gear, respectively. The multi-plate magnetorheological damping assembly includes an excitation coil, a magnetorheological working cavity, multiple inner plates and multiple outer plates. The multiple inner plates and multiple outer plates are staggered along the axial direction of the rotor-sun gear assembly in the magnetorheological working cavity, and the magnetorheological working cavity is filled with a magnetorheological medium. The multiple inner disks are circumferentially limited to the rotor-sun gear assembly, the multiple outer disks are fixedly disposed relative to the housing, and the excitation coil is used to generate a magnetic field acting on the magnetorheological medium.

[0008] Preferably, the multi-plate magnetorheological damping assembly is disposed on one axial side of the motor drive assembly; The joint actuator also includes a damper connection end cap, which is fixedly connected to the housing. The multi-plate magnetorheological damping assembly also includes a magnetically conductive lower base, which is fixedly connected to the damper connection end cap.

[0009] Preferably, the multi-plate magnetorheological damping assembly further includes an inner plate mounting fastener and an inner plate input connector; The multiple inner discs are circumferentially limited and connected to the inner disc mounting fasteners. The inner disc input connector is fixedly connected to the axial end of the rotor-sun gear assembly and is circumferentially limited and connected to the inner disc mounting fasteners.

[0010] Preferably, the multi-plate magnetorheological damping assembly further includes a first sealing cover, the inner plate input connector is provided with a first flat keyway, the first sealing cover is provided with a second flat keyway, the inner plate mounting and fixing component is provided with a flat key, and the flat key is respectively fitted into the first flat keyway and the second flat keyway.

[0011] Preferably, the multi-plate magnetorheological damping assembly further includes a magnetically conductive lower base and an outer plate mounting fastener, wherein the multiple outer plates are circumferentially limited and connected to the outer plate mounting fastener; The outer disk mounting fastener is provided with an outer disk mounting fastener fitting groove, and the magnetic bottom is provided with a bottom fitting part. The bottom fitting part is fitted into the outer disk mounting fastener fitting groove to restrict the circumferential relative movement between the outer disk mounting fastener and the magnetic bottom. The magnetically conductive lower base is fixedly disposed relative to the housing.

[0012] Preferably, the multi-plate magnetorheological damping assembly further includes multiple inner plate spacers and multiple outer plate spacers; An inner disk spacer is provided between two adjacent inner disks, and an outer disk spacer is provided between two adjacent outer disks. A shear gap filled with the magnetorheological medium is formed between adjacent inner disks and outer disks.

[0013] Preferably, the multi-plate magnetorheological damping assembly further includes a magnetically conductive upper cover and a magnetically conductive lower base, wherein the magnetically conductive upper cover and the magnetically conductive lower base form a magnetic flux path passing through the magnetorheological working cavity, and the plurality of shear gaps are located in the magnetic flux path.

[0014] Preferably, the multi-plate magnetorheological damping assembly further includes a magnetically conductive upper cover, a magnetically conductive lower base, a first sealing cover, a second sealing cover, and a second dynamic sealing ring; The magnetically conductive upper cover, the magnetically conductive lower bottom, the first sealing cover, and the second sealing cover together form the magnetorheological working cavity; The magnetically conductive bottom is provided with a dynamic sealing ring receiving groove, and the second dynamic sealing ring is disposed in the dynamic sealing ring receiving groove.

[0015] Preferably, the rotor-sun gear assembly is rotatably supported on the housing by a first support bearing and is axially positioned by a bearing positioning ring; The output planetary carrier is rotatably supported on the housing by an output end bearing, and a second support bearing is provided between the rotor-sun gear assembly and the output planetary carrier.

[0016] Preferably, the output planetary carrier includes a planetary carrier portion and an output shaft portion, wherein the planetary carrier portion and the output shaft portion are integrally formed.

[0017] Beneficial technical effects of the present invention: (1) The present invention fixes the rotor part and the sun gear tooth part together and rotates synchronously. The inner disk of the multi-plate magnetorheological damping assembly is circumferentially limited and connected to the rotor-sun gear assembly, and the outer disk is fixed relative to the housing. Thus, the rotor-sun gear assembly is shared by the motor rotation side, the planetary transmission input side and the magnetorheological damping rotation side. This can reduce the independent transmission connection structure between each functional part, shorten the transmission path of driving torque and damping torque, and help improve the structural integration and compactness of the joint actuator.

[0018] (2) The present invention arranges multiple inner disks and multiple outer disks in an alternating manner along the axial direction of the rotor-sun gear assembly, which can form multiple magnetorheological shear interfaces distributed along the axial direction under a given radial dimension, thereby increasing the effective shear area of ​​the magnetorheological medium and thus improving the damping torque output capability of the multi-plate magnetorheological damping assembly.

[0019] (3) The present invention generates a magnetic field acting on the magnetorheological medium through the excitation coil, which can change the shear resistance of the magnetorheological medium when the inner and outer disks move relative to each other, thereby realizing the adjustment of the damping torque acting on the rotor-sun gear assembly, and transmitting the damping effect to the output planetary carrier through the planetary gear, which is beneficial to improving the smoothness of joint movement and the energy consumption buffering capacity when subjected to external impact. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of the joint actuator proposed in this invention; Figure 2 This is an exploded view of the joint actuator proposed in this invention; Figure 3 This is a cross-sectional view of the multi-plate magnetorheological damping assembly of the joint actuator proposed in this invention.

[0021] In the diagram: 1-Motor end cover, 2-Damper connecting end cover, 3-Inner connecting part of end cover, 4-Encoded magnetic ring, 5-Magnetic ring base, 6-Multi-plate magnetorheological damping assembly, 7-Inner disc input connector, 8-First flat keyway, 9-Rotor-sun gear assembly, 10-Connecting threaded hole, 11-Sun gear teeth, 12-Bearing positioning ring, 13-First support bearing, 14-Stator coil, 15-Planet gear, 16-Planet gear shaft, 17-Housing, 18-Gear ring, 19-Output end bearing, 20-Output planetary carrier, 21-Second support bearing, 22-Magnetic guide cover, 23-First 24-Dynamic sealing ring, 25-First sealing cover, 26-Second flat keyway, 27-First static sealing ring, 28-Inner disc spacer, 29-Outer disc spacer, 30-Outer disc, 31-Inner disc mounting fastener, 32-Flat key, 33-Outer disc mounting fastener, 34-Outer disc mounting fastener fitting groove, 35-Second static sealing ring, 36-Second sealing cover, 37-Second dynamic sealing ring, 38-Excitation coil, 39-Magnetic guide bottom, 40-Bottom bottom fitting part, 41-Bottom bottom end cover connecting part, 42-Dynamic sealing ring receiving groove, 43-Magnetorheological working chamber. Detailed Implementation

[0022] The present invention will be further explained below with reference to specific embodiments.

[0023] In the following description, the direction of the rotation axis of the rotor-sun gear assembly 9 is defined as the axial direction, the direction perpendicular to the rotation axis is defined as the radial direction, and the direction surrounding the rotation axis is defined as the circumferential direction. The shapes, quantities, and dimensions of the components in the accompanying drawings are only for illustrating the structural relationships between the components and do not constitute a limitation on the actual product.

[0024] Example 1 like Figure 1 and Figure 2 As shown, this embodiment provides a joint actuator, including a housing 17, a motor drive assembly, a planetary transmission assembly, an output planetary carrier 20, and a multi-plate magnetorheological damping assembly 6.

[0025] In this embodiment, the housing 17 is a motor gear ring housing for mounting the motor drive assembly and the planetary transmission assembly. A motor end cover 1 is provided at one axial end of the housing 17. The motor end cover 1 is fixedly connected to the housing 17 and together with the housing 17 forms an internal space for mounting the motor drive assembly and the planetary transmission assembly. In other embodiments, the housing 17 may also be composed of multiple housing components that are fixedly connected to each other.

[0026] The motor drive assembly includes a stator coil 14 and a rotor-sun gear assembly 9. The stator coil 14 is disposed on the housing 17, and the rotor-sun gear assembly 9 is rotatably disposed relative to the housing 17.

[0027] The rotor-sun gear assembly 9 includes a rotor portion and a sun gear tooth portion 11, which are fixedly connected and rotate synchronously. In this embodiment, the rotor portion and the sun gear tooth portion 11 are integrally formed, so that the rotor-sun gear assembly 9 serves simultaneously as a rotating component of the motor drive assembly and an input component of the planetary transmission assembly. In other embodiments, the rotor portion and the sun gear tooth portion 11 can also be machined separately and then fixedly connected by fastening, interference fit, welding, or other methods that can restrict their relative rotation.

[0028] The rotor-sun gear assembly 9 can also be provided with a connecting threaded hole 10, which is located at the end of the rotor-sun gear assembly 9 facing the multi-plate magnetorheological damping assembly 6, and is used to fix the inner plate input connector 7.

[0029] The planetary transmission assembly includes planetary gears 15 and a gear ring 18. The gear ring 18 is fixedly disposed relative to the housing 17. In this embodiment, the gear ring 18 can be fixedly installed as an independent component on the inner circumferential side of the housing 17, or it can be directly formed on the inner circumferential surface of the housing 17.

[0030] The output planetary carrier 20 is disposed within the housing 17 and is rotatable relative to the housing 17. Multiple planetary gears 15 are spaced circumferentially along the output planetary carrier 20, and each planetary gear 15 is rotatably mounted on the output planetary carrier 20 via a planetary gear shaft 16. The planetary gear shaft 16 is fixedly connected to the output planetary carrier 20, and the planetary gear 15 is rotatable around its corresponding planetary gear shaft 16.

[0031] The radially inner side of each planetary gear 15 meshes with the sun gear teeth 11 of the rotor-sun gear assembly 9, and the radially outer side of each planetary gear 15 meshes with the gear ring 18. Since the gear ring 18 is fixed relative to the housing 17, when the stator coil 14 drives the rotor-sun gear assembly 9 to rotate, the sun gear teeth 11 drive the planetary gears 15 to rotate on their own axis and revolve around the gear ring 18, thereby driving the output planetary carrier 20 to rotate, achieving deceleration and torque increase output.

[0032] In this embodiment, the output planetary carrier 20 includes a planetary carrier portion and an output shaft portion, which are integrally formed to create an integrated output shaft-planetary carrier structure. The planetary carrier portion is used to mount the planetary gear shaft 16 and the planetary gears 15, and the output shaft portion is used to connect to a robotic arm link, a robot leg link, a rehabilitation training component, or other loads requiring rotary drive. In other embodiments, the output shaft portion can also be fixedly connected to the planetary carrier portion as an independent component.

[0033] The rotor-sun gear assembly 9 is rotatably supported on the housing 17 by a first support bearing 13, which is located at the bearing mounting position on the housing 17. The rotor-sun gear assembly 9 is also axially positioned by a bearing locating ring 12 to limit axial movement of the rotor-sun gear assembly 9 relative to the housing 17.

[0034] The output planetary carrier 20 is rotatably supported on the housing 17 via the output end bearing 19. A second support bearing 21 is provided between the rotor-sun gear assembly 9 and the output planetary carrier 20. This second support bearing 21, which can be referred to as an inter-assembly support bearing, is used to support the relative rotation between the rotor-sun gear assembly 9 and the output planetary carrier 20. Through the combined action of the first support bearing 13, the output end bearing 19, and the second support bearing 21, the coaxiality and rotational stability of the rotor-sun gear assembly 9 and the output planetary carrier 20 can be improved.

[0035] The multi-plate magnetorheological damping assembly 6 is disposed on one axial side of the motor drive assembly and is arranged coaxially with the rotor-sun gear assembly 9. The joint actuator also includes a damper connection end cover 2, which is fixedly connected to the housing 17, so that the multi-plate magnetorheological damping assembly 6 can be installed on the axial end of the joint actuator.

[0036] The damper connecting end cap 2 is provided with an inner connecting part 3. The multi-plate magnetorheological damping assembly 6 includes a magnetically conductive lower base 39, which is provided with a lower base end cap connecting part 41. The inner connecting part 3 and the lower base end cap connecting part 41 cooperate with each other and are fixedly connected, thereby fixing the magnetically conductive lower base 39 relative to the housing 17 via the damper connecting end cap 2. The fixed connection can be achieved by threaded connection, screw connection, fitting connection, or a combination of the above connection methods.

[0037] The multi-plate magnetorheological damping assembly 6 also includes a magnetically conductive upper cover 22, an excitation coil 38, a magnetorheological working cavity 43, multiple inner discs 28, and multiple outer discs 30. The magnetically conductive upper cover 22, the magnetically conductive lower base 39, the first sealing cover 24, and the second sealing cover 36 together form the magnetorheological working cavity 43, which is filled with a magnetorheological medium.

[0038] In this embodiment, the magnetorheological medium can be a magnetorheological fluid. The magnetorheological fluid comprises a carrier fluid and magnetic particles dispersed within it. When no magnetic field is applied or the magnetic field is weak, the magnetorheological fluid exhibits relatively low shear resistance. After a magnetic field is applied, the magnetic particles tend to align along the direction of the magnetic field, increasing the yield stress and shear resistance of the magnetorheological fluid.

[0039] Multiple inner disks 28 and multiple outer disks 30 are staggered along the axial direction of the rotor-sun gear assembly 9 within the magnetorheological working chamber 43. Both the inner disks 28 and the outer disks 30 can be annular disks. The inner disks 28 are located between adjacent outer disks 30, or the outer disks 30 are located between adjacent inner disks 28, so that a shear gap for filling the magnetorheological medium is formed between adjacent inner disks 28 and outer disks 30.

[0040] The multi-plate magnetorheological damping assembly 6 also includes multiple inner plate spacers 27 and multiple outer plate spacers 29. Inner plate spacers 27 are provided between two adjacent inner plates 28 to limit the axial distance between them; outer plate spacers 29 are provided between two adjacent outer plates 30 to limit the axial distance between them.

[0041] The shear gap between the inner disc 28 and the outer disc 30 can be adjusted by changing the axial thickness of the inner disc spacer 27 and the outer disc spacer 29. Given a radial dimension, multiple sets of inner discs 28 and outer discs 30 stacked axially can form multiple axially distributed shear interfaces.

[0042] The inner disc 28 is circumferentially limited to the rotor-sun gear assembly 9 via the inner disc mounting fastener 31 and the inner disc input connector 7. Specifically, multiple inner discs 28 are circumferentially limited to the inner disc mounting fastener 31, so that the inner discs 28 can rotate synchronously with the inner disc mounting fastener 31.

[0043] One end of the inner disc input connector 7 is fixedly connected to the threaded hole 10 at the axial end of the rotor-sun gear assembly 9 via a fastener, and the other end of the inner disc input connector 7 is circumferentially limited and connected to the inner disc mounting fastener 31. Thus, the rotation of the rotor-sun gear assembly 9 can be transmitted to multiple inner discs 28 via the inner disc input connector 7 and the inner disc mounting fastener 31.

[0044] In this embodiment, the inner disc input connector 7 is provided with a first flat keyway 8, the first sealing cover 24 is provided with a second flat keyway 25, and the inner disc mounting fastener 31 is provided with a flat key 32. The flat key 32 is respectively engaged with the first flat keyway 8 and the second flat keyway 25, so that the inner disc input connector 7, the first sealing cover 24 and the inner disc mounting fastener 31 are kept in circumferential limiting position, so as to transmit the rotation of the rotor-sun gear assembly 9 to the inner disc mounting fastener 31 and the multiple inner discs 28 via the inner disc input connector 7.

[0045] In other embodiments, the inner disc mounting fastener 31 and the inner disc input connector 7 can also form a circumferential limiting connection through splines, slots, pins, screws, interference fits, or a combination of the aforementioned connection methods.

[0046] Multiple outer discs 30 are circumferentially limited and connected to the outer disc mounting fastener 33. The outer disc mounting fastener 33 is provided with an outer disc mounting fastener fitting groove 34, and the magnetically conductive lower base 39 is provided with a lower base fitting part 40 that is adapted to the outer disc mounting fastener fitting groove 34.

[0047] The lower bottom fitting part 40 is fitted into the fitting groove 34 of the outer disc mounting fastener to restrict the circumferential relative movement between the outer disc mounting fastener 33 and the magnetically conductive lower bottom 39. Since the magnetically conductive lower bottom 39 is fixed relative to the housing 17 through the damper connecting end cap 2, the multiple outer discs 30 are also fixed relative to the housing 17.

[0048] Thus, the multi-plate magnetorheological damping assembly 6 forms a complete damping torque transmission path: the inner plate 28 is connected to the rotor-sun gear assembly 9 via the inner plate mounting fastener 31 and the inner plate input connector 7, forming the rotating side; the outer plate 30 is connected to the housing 17 via the outer plate mounting fastener 33, the magnetic bottom 39 and the damper connecting end cover 2, forming the fixed side.

[0049] The excitation coil 38 is disposed within the magnetic structure formed by the magnetically conductive upper cover 22 and the magnetically conductive lower base 39. The magnetically conductive upper cover 22 and the magnetically conductive lower base 39 form a magnetic flux path through the magnetorheological working cavity 43, and multiple shear gaps between adjacent inner disks 28 and outer disks 30 are located in this magnetic flux path.

[0050] When the excitation coil 38 is energized, it generates a magnetic field. The magnetic flux forms a magnetic flux path along the magnetically conductive upper cover 22, the magnetically conductive lower base 39, and the area near the disk assembly, and passes through the shear gap in the magnetorheological working cavity 43. By changing the excitation current of the excitation coil 38, the magnetic field strength acting on the magnetorheological medium can be changed, thereby changing the yield stress and shear resistance of the magnetorheological medium.

[0051] To reduce the possibility of magnetorheological medium leakage, the multi-plate magnetorheological damping assembly 6 is also equipped with a sealing structure. The sealing structure includes a first sealing cover 24, a second sealing cover 36, and a second dynamic sealing ring 37. The magnetically conductive lower base 39 is provided with a dynamic sealing ring receiving groove 42, and the second dynamic sealing ring 37 is installed in the dynamic sealing ring receiving groove 42 to seal the corresponding rotational mating position of the magnetically conductive lower base 39.

[0052] Optionally, the sealing structure further includes a first dynamic sealing ring 23, a first static sealing ring 26, and a second static sealing ring 35. The first dynamic sealing ring 23 and the second dynamic sealing ring 37 are disposed in mating positions where there is relative rotation, while the first static sealing ring 26 and the second static sealing ring 35 are disposed on relatively fixed mating surfaces. Each sealing ring, together with the first sealing cover 24, the second sealing cover 36, the magnetic upper cover 22, and the magnetic lower base 39, restricts the leakage of the magnetorheological medium from the magnetorheological working chamber 43 to the outside.

[0053] Optionally, the joint actuator also includes an encoding magnetic ring 4 and a magnetic ring base 5. The encoding magnetic ring 4 is mounted on the magnetic ring base 5 and cooperates with a position detection element to detect the position, angle, or speed of the corresponding rotating part in the joint actuator. The detection results can be provided to the controller, which then controls the stator coil 14 and the excitation coil 38 respectively.

[0054] Example 2 This embodiment describes the driving and damping process of the joint actuator.

[0055] When the stator coil 14 is energized, an electromagnetic interaction is generated between the stator coil 14 and the rotor portion of the rotor-sun gear assembly 9, driving the rotor-sun gear assembly 9 to rotate relative to the housing 17. Since the rotor portion and the sun gear tooth portion 11 are fixedly connected and rotate synchronously, the sun gear tooth portion 11 rotates synchronously with the rotor portion.

[0056] The sun gear 11 drives the multiple planet gears 15 meshing with it to rotate. Since the ring gear 18 is fixed relative to the housing 17, each planet gear 15 revolves around the ring gear 18 while rotating on its own axis, and drives the output planet carrier 20 to rotate via the planet gear shaft 16, outputting driving torque outward from the output shaft of the output planet carrier 20.

[0057] When the rotor-sun gear assembly 9 rotates, the inner disk input connector 7, the inner disk mounting fastener 31, and the multiple inner disks 28 rotate synchronously with the rotor-sun gear assembly 9. Since the multiple outer disks 30 are fixed relative to the housing 17 by the outer disk mounting fastener 33 and the magnetically conductive lower base 39, relative motion occurs between the inner disks 28 and the outer disks 30, and the magnetorheological medium located between adjacent inner disks 28 and outer disks 30 is subjected to shearing action.

[0058] When the excitation coil 38 is not energized or the excitation current is small, the magnetic field acting on the magnetorheological medium is weak, the yield stress of the magnetorheological medium is low, the shear resistance between the inner disk 28 and the outer disk 30 is small, and the damping torque applied by the multi-plate magnetorheological damping assembly 6 to the rotor-sun gear assembly 9 is relatively small.

[0059] When the excitation current of the excitation coil 38 increases, the magnetic field passing through the magnetorheological working cavity 43 and multiple shear gaps is enhanced. The magnetic particles in the magnetorheological medium form a chain or columnar arrangement along the direction of the magnetic field. The yield stress of the magnetorheological medium increases, and the shear resistance between the inner disk 28 and the outer disk 30 increases accordingly. The damping torque applied by the multi-plate magnetorheological damping assembly 6 to the rotor-sun gear assembly 9 increases.

[0060] The damping torque, after acting on the rotor-sun gear assembly 9, is reflected to the joint output end through the planetary transmission path formed by the sun gear teeth 11, planet gears 15, and output planet carrier 20. Therefore, the active driving torque generated by the motor drive assembly and the damping torque generated by the multi-plate magnetorheological damping assembly 6 can act on the output planet carrier 20 through the same rotor-sun gear assembly 9 and planetary transmission assembly.

[0061] During normal joint movement, a small excitation current can be input to the excitation coil 38 according to the target speed, actual speed, or external load condition of the joint to keep the joint in a low-damping state. When it is necessary to reduce the joint movement speed, suppress output vibration, or buffer external impact, the excitation current of the excitation coil 38 can be increased to allow the multi-plate magnetorheological damping component 6 to enter a higher-damping state.

[0062] When the joint needs to maintain its current position, an active holding torque can be provided by the stator coil 14, and an auxiliary damping torque can be provided by the multi-plate magnetorheological damping assembly 6 through the excitation coil 38. Thus, the damping characteristics at the joint output end can be adjusted according to different operating conditions.

[0063] The controller in this embodiment can be a robot controller, a motor driver, or an independent damping controller. The controller can control the drive current of the stator coil 14 and the excitation current of the excitation coil 38 according to the position detection signal, speed detection signal, drive current signal, or external sensor signal corresponding to the coded magnetic ring 4.

[0064] It should be noted that the coded magnetic ring 4 and its control method are used to further improve the joint control performance, but are not a necessary condition for realizing the mechanical transmission relationship between the rotor-sun gear assembly 9, the planetary transmission assembly and the multi-plate magnetorheological damping assembly 6.

[0065] Example 3 This embodiment describes the assembly process of the joint actuator.

[0066] When assembling the multi-plate magnetorheological damping assembly 6, multiple inner plates 28 and multiple inner plate spacers 27 are first installed sequentially on the inner plate mounting fastener 31, so that the axial distance between two adjacent inner plates 28 is limited by the corresponding inner plate spacers 27, thereby forming an inner plate group.

[0067] Multiple outer discs 30 and multiple outer disc spacers 29 are sequentially installed on the outer disc mounting fastener 33, so that the axial distance between two adjacent outer discs 30 is limited by the corresponding outer disc spacers 29, thereby forming an outer disc group.

[0068] Subsequently, the inner and outer disc groups are assembled in an axially staggered manner, so that each inner disc 28 extends between adjacent outer discs 30, and a shear gap is maintained between adjacent inner discs 28 and outer discs 30.

[0069] The lower bottom fitting part 40 is inserted into the fitting groove 34 of the outer disc mounting fastener, so that the outer disc mounting fastener 33 and the magnetically conductive lower bottom 39 form a circumferential limiting connection. The flat key 32 on the inner disc mounting fastener 31 is aligned and fitted with the first flat keyway 8 of the inner disc input connector 7 and the second flat keyway 25 of the first sealing cover 24, so that the inner disc input connector 7, the first sealing cover 24 and the inner disc mounting fastener 31 form a circumferential limiting connection.

[0070] The excitation coil 38, the magnetically conductive upper cover 22, the first sealing cover 24, the second sealing cover 36, and the corresponding dynamic and static sealing rings are installed, so that the magnetically conductive upper cover 22, the magnetically conductive lower cover 39, the first sealing cover 24, and the second sealing cover 36 together form the magnetorheological working chamber 43. Magnetorheological medium is injected into the magnetorheological working chamber 43 and sealed.

[0071] The inner disc input connector 7 is fixedly connected to the axial end of the rotor-sun gear assembly 9, and the damper connection end cap 2 is fixedly connected to the housing 17 and the magnetic bottom 39 respectively, thereby completing the axial integration of the multi-plate magnetorheological damping assembly 6 and the motor drive assembly.

[0072] When assembling the planetary transmission assembly, the first support bearing 13 is installed at the corresponding installation position of the housing 17, the rotor-sun gear assembly 9 is installed into the housing 17, and the rotor-sun gear assembly 9 is axially positioned by the bearing positioning ring 12.

[0073] Planetary gears 15 are installed on their corresponding planetary gear shafts 16, which are then fixed to the output planetary carrier 20. Each planetary gear 15 is then engaged with the sun gear teeth 11 and the ring gear 18. The output end bearing 19 and the second support bearing 21 are then installed to ensure stable rotation of the output planetary carrier 20 relative to the housing 17.

[0074] After the above assembly is completed, the rotor, sun gear 11 and inner disk 28 can rotate synchronously, the gear ring 18, magnetic bottom 39 and outer disk 30 are fixed relative to the housing 17, and the output planet carrier 20 outputs rotation as the output component of the planetary transmission assembly.

[0075] Example 4 To verify the damping adjustment capability of the multi-plate magnetorheological damping component 6, a damping torque test was conducted on a prototype equipped with the multi-plate magnetorheological damping component 6.

[0076] During the test, the excitation current of the excitation coil 38 and the angular velocity of the rotor-sun gear assembly 9 were adjusted respectively, and the damping torque generated by the multi-plate magnetorheological damping assembly 6 was measured. The test range of the excitation current I was 0.1A to 2.0A, and the test range of the angular velocity ω was 0.5rad / s to 9.5rad / s. Tables 1 and 2 list the complete measured results of the damping torque corresponding to 20 excitation current levels and 19 angular velocity levels, totaling 380 combined measured points; the data in the tables are all measured values ​​and do not include interpolated or fitted points.

[0077] Table 1. Measured results of damping torque (angular velocity 0.5-5 rad / s; unit N·m) Table 2. Measured results of damping torque (angular velocity 5.5-9.5 rad / s; unit N·m) The test results in Tables 1 and 2 show that, within the above test range, the measured damping torque ranges from 1.700 N·m to 20.447 N·m. At the same angular velocity, the damping torque generally increases with increasing excitation current; similarly, at the same excitation current, the damping torque generally increases with increasing angular velocity.

[0078] For example, when the angular velocity is 5.0 rad / s, increasing the excitation current from 0.1 A to 2.0 A increases the measured damping torque from 3.400 N·m to 15.700 N·m. These results demonstrate that by adjusting the excitation current of the excitation coil 38, the magnetic field strength acting on the magnetorheological medium can be changed, thereby altering the shear resistance between the inner disk 28 and the outer disk 30, thus achieving damping torque adjustment.

[0079] Through the above implementation, the rotor-sun gear assembly 9 is shared by the motor rotating side, the planetary transmission input side, and the magnetorheological damping rotating side, which can reduce the independent transmission connection structure between each functional component; multiple inner disks 28 and multiple outer disks 30 are staggered along the axial direction, which can form multiple shearing interfaces under a given radial dimension; the magnetic field generated by the excitation coil 38 can adjust the shear resistance of the magnetorheological medium and make the damping torque act on the output planetary carrier 20 through the planetary transmission assembly, thereby realizing the integration of active drive, deceleration output and adjustable damping functions.

[0080] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application. The scope of this application is defined by the appended claims and their equivalents, all of which should be included within the protection scope of this application.

Claims

1. A joint actuator, characterized in that, It includes a housing (17), a motor drive assembly, a planetary transmission assembly, an output planetary carrier (20), and a multi-plate magnetorheological damping assembly (6). The motor drive assembly includes a stator coil (14) and a rotor-sun gear assembly (9). The stator coil (14) is disposed on the housing (17). The rotor-sun gear assembly (9) is rotatably disposed relative to the housing (17). The rotor-sun gear assembly (9) includes a rotor portion and a sun gear tooth portion (11). The rotor portion and the sun gear tooth portion (11) are fixedly connected and rotate synchronously. The planetary transmission assembly includes planetary gears (15) and a gear ring (18). The gear ring (18) is connected to the housing (17). The planetary gears (15) are rotatably mounted on the output planet carrier (20) and mesh with the sun gear teeth (11) and the gear ring (18) respectively. The multi-plate magnetorheological damping assembly (6) includes an excitation coil (38), a magnetorheological working cavity (43), multiple inner plates (28) and multiple outer plates (30). The multiple inner plates (28) and multiple outer plates (30) are staggered in the magnetorheological working cavity (43) along the axial direction of the rotor-sun gear assembly (9). The magnetorheological working cavity (43) is filled with a magnetorheological medium. Multiple inner discs (28) are circumferentially limited to the rotor-sun gear assembly (9), multiple outer discs (30) are fixedly disposed relative to the housing (17), and the excitation coil (38) is used to generate a magnetic field acting on the magnetorheological medium.

2. The joint actuator according to claim 1, characterized in that, The multi-plate magnetorheological damping assembly (6) is disposed on one axial side of the motor drive assembly; The joint actuator also includes a damper connection end cap (2), which is fixedly connected to the housing (17). The multi-plate magnetorheological damping assembly (6) also includes a magnetically conductive lower base (39), which is fixedly connected to the damper connection end cap (2).

3. The joint actuator according to claim 1, characterized in that, The multi-plate magnetorheological damping assembly (6) also includes an inner plate mounting fastener (31) and an inner plate input connector (7). Multiple inner discs (28) are circumferentially limited to the inner disc mounting fastener (31), and the inner disc input connector (7) is fixedly connected to the axial end of the rotor-sun gear assembly (9) and is circumferentially limited to the inner disc mounting fastener (31).

4. The joint actuator according to claim 3, characterized in that, The multi-plate magnetorheological damping assembly (6) also includes a first sealing cover (24), the inner plate input connector (7) is provided with a first flat keyway (8), the first sealing cover (24) is provided with a second flat keyway (25), the inner plate mounting fastener (31) is provided with a flat key (32), and the flat key (32) is respectively fitted with the first flat keyway (8) and the second flat keyway (25).

5. The joint actuator according to claim 1, characterized in that, The multi-plate magnetorheological damping assembly (6) further includes a magnetically conductive lower base (39) and an outer plate mounting fastener (33), wherein the multiple outer plates (30) are circumferentially limited and connected to the outer plate mounting fastener (33); The outer disk mounting fastener (33) is provided with an outer disk mounting fastener fitting groove (34), and the magnetic bottom (39) is provided with a bottom fitting part (40). The bottom fitting part (40) is fitted into the outer disk mounting fastener fitting groove (34) to restrict the circumferential relative movement between the outer disk mounting fastener (33) and the magnetic bottom (39). The magnetically conductive lower base (39) is fixed relative to the housing (17).

6. The joint actuator according to claim 1, characterized in that, The multi-plate magnetorheological damping assembly (6) also includes multiple inner plate spacers (27) and multiple outer plate spacers (29). An inner disk spacer (27) is provided between two adjacent inner disks (28), and an outer disk spacer (29) is provided between two adjacent outer disks (30). A shear gap filled with the magnetorheological medium is formed between adjacent inner disks (28) and outer disks (30).

7. The joint actuator according to claim 6, characterized in that, The multi-plate magnetorheological damping assembly (6) further includes a magnetically conductive upper cover (22) and a magnetically conductive lower base (39). The magnetically conductive upper cover (22) and the magnetically conductive lower base (39) form a magnetic flux path through the magnetorheological working cavity (43), and multiple shear gaps are located in the magnetic flux path.

8. The joint actuator according to claim 1, characterized in that, The multi-plate magnetorheological damping assembly (6) also includes a magnetically conductive upper cover (22), a magnetically conductive lower base (39), a first sealing cover (24), a second sealing cover (36), and a second dynamic sealing ring (37). The magnetically conductive upper cover (22), the magnetically conductive lower base (39), the first sealing cover (24), and the second sealing cover (36) together form the magnetorheological working cavity (43). The magnetic bottom (39) is provided with a dynamic sealing ring receiving groove (42), and the second dynamic sealing ring (37) is disposed in the dynamic sealing ring receiving groove (42).

9. The joint actuator according to claim 1, characterized in that, The rotor-sun gear assembly (9) is rotatably supported on the housing (17) by the first support bearing (13) and is axially positioned by the bearing positioning ring (12); The output planetary carrier (20) is rotatably supported on the housing (17) by an output end bearing (19), and a second support bearing (21) is provided between the rotor-sun gear assembly (9) and the output planetary carrier (20).

10. The joint actuator according to claim 1, characterized in that, The output planetary carrier (20) includes a planetary carrier section and an output shaft section, wherein the planetary carrier section and the output shaft section are integrally formed.

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