Hollow flexible joint module and foot type robot

Abstract

The invention discloses a hollow flexible joint module and a foot type robot, and relates to the technical field of joints. The device specifically comprises a shell, an output shaft body, a frameless motor, a harmonic reducer and a flexible assembly are arranged in the shell, and the output shaft body is rotationally connected to the middle of the shell; the frameless motor is arranged at one end of the shell; the input end of the harmonic reducer is connected with the output end of the frameless motor; the flexible assembly is connected to the output end of the harmonic reducer, and the middle is connected with the output shaft body. The frameless motor drives the output shaft body to rotate through the harmonic reducer and the flexible assembly in sequence. The output shaft is installed in the middle of the flexible assembly, the flexible assembly and the harmonic reducer jointly participate in torque transmission, when the output shaft body is impacted, the flexible assembly reduces impact force borne by the harmonic reducer through deformation of the flexible assembly, and the service life of the harmonic reducer is prolonged; and meanwhile, the torque of the output shaft body is ensured through deformation of the flexible assembly.

Description

Technical Field

[0001] The present invention relates to the technical field of joints, and in particular to a hollow flexible joint module and a foot-type robot. Background Art

[0002] Currently, rotary joint modules are widely used as power sources in the field of legged robots. In order to improve the accuracy of joint control, most robots are usually equipped with rigid reducers, such as planetary reducers, cycloid reducers, etc. for transmission. However, during the actual movement of legged robots, their joints will inevitably be subjected to short-term impact loads, which can easily lead to damage to the gears, motors or related structural components of the rigid reducer. In addition, if you want to carry out torque closed-loop control for robot joint modules with large reduction ratios, you must also add a torque sensor to the output end of the reducer to measure the load torque borne by the joint output end. However, this approach has invisibly increased the size of the robot joint module, thereby reducing its overall integration.

[0003] Traditional rigid joint modules are widely used in many fields such as robotics and automation. Generally speaking, a rigid joint module of a robot is mainly composed of a motor, a rigid reducer, an encoder and a driver. In the current robot joint modules, the reducers mainly use rigid reducers (including planetary, cycloid and other types) or harmonic reducers. Once a rigid reducer encounters a short-term impact load, its gears, motors or structural components are extremely susceptible to damage; although the harmonic reducer will produce a certain degree of flexible deformation when subjected to a load, thus having a certain degree of flexibility, this flexible deformation will affect the service life of the harmonic reducer, and may even cause the harmonic reducer to jump teeth under the action of an impact load. At the same time, it is difficult to achieve smooth and precise force control, which will cause varying degrees of damage to the internal structure of the joint module.

[0004] Therefore, the present application reduces the impact of the harmonic reducer while ensuring precise control of the torque under the condition of joint module integration. Summary of the Invention

[0005] The main purpose of the present invention is to provide a hollow flexible joint module and a legged robot, aiming to optimize the structure of the joint module, reduce the impact of the harmonic reducer, and improve the transmission accuracy.

[0006] In order to achieve the above object, the present invention proposes a hollow flexible joint module, comprising a shell, wherein the interior of the shell is provided with:

[0007] an output shaft body, which is rotatably connected to the middle portion of the housing;

[0008] a frameless motor disposed at one end of the housing;

[0009] a harmonic reducer, the input end of which is connected to the output end of the frameless motor; and

[0010] A flexible component connected to the output end of the harmonic reducer, with the middle portion connected to the output shaft;

[0011] Wherein, the frameless motor drives the output shaft to rotate through the harmonic reducer and the flexible component in sequence.

[0012] Furthermore, the flexible component includes a flexible ring and a connecting frame, the flexible ring is connected to the connecting frame, the inner wall of the flexible ring is connected to a curved portion, the curved portion can be deformed, and the curved portion is located at the center of the flexible ring and a transmission groove is provided, and the transmission groove is connected to the output shaft.

[0013] Furthermore, the curved portion is S-shaped with the flexible ring as the center.

[0014] Furthermore, at least two encoders are disposed inside the housing, wherein the two encoders are arranged on both sides of the flexible component to obtain different rotational speeds on both sides of the flexible component.

[0015] Furthermore, the frameless motor includes a motor winding and a rotor that cooperate with each other, the motor winding is connected to the housing, the inner ring of the rotor is connected to the motor shaft, and one end of the motor shaft is connected to the input end of the harmonic reducer.

[0016] Furthermore, the harmonic reducer includes a steel wheel, a flexible wheel and a wave generator that are matched in sequence, the steel wheel is connected to the inner wall of the shell, the wave generator is connected to the motor shaft, the flexible wheel is meshed with the steel wheel, and one side of the flexible wheel is connected to the connecting frame.

[0017] Furthermore, the shell includes shell one, shell two and shell three, and the shell one, shell two and shell three are connected in sequence and combined to form a shell with a cavity.

[0018] Furthermore, the inner wall of the second shell protrudes to form an extension block, and one of the encoders is configured on a side of the extension block facing the flexible component.

[0019] Furthermore, the encoder includes a reading head and a magnetic ring, and the reading head and the magnetic ring are respectively connected to the side wall of the extension block and the connecting frame facing each other.

[0020] The present application also discloses a legged robot, at least one joint of which is equipped with the above-mentioned hollow flexible joint module.

[0021] The above technical solution has the following advantages:

[0022] The present invention adopts a harmonic reducer and a flexible component transmission arranged at the output end of the frameless motor, and the output shaft is installed in the middle of the flexible component, so that the flexible component and the harmonic reducer jointly participate in the torque transmission. The flexible component participates in the main deformation. When the output shaft is impacted, the flexible component reduces the impact force on the harmonic reducer through its own deformation, thereby increasing the service life of the harmonic reducer. At the same time, the torque of the output shaft is also ensured by the deformation of the flexible component.

[0023] The present invention sets encoders on both sides of the flexible component, and obtains the rotation angles on both sides of the flexible component through the encoder. The rotation angles on both sides of the flexible component and the stiffness of the bending part can be used to obtain the torque of the output shaft. The deformation measurement accuracy of the flexible component is higher, and the obtained load torque accuracy is higher. Since the harmonic reducer has a certain flexibility, it will produce a certain amount of deformation when it is loaded. It avoids using the difference between the output end angle of the flexible component and the high-speed end angle of the motor multiplied by the reduction ratio to avoid a large angle error, which helps to improve the measurement accuracy of the output torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0025] Figure 1 It is a structural schematic diagram of the present invention;

[0026] Figure 2 It is a cross-sectional three-dimensional structural diagram of the present invention;

[0027] Figure 3 It is the internal structure diagram of the present invention;

[0028] Figure 4 This is an exploded structural diagram of the flexible component of the present invention;

[0029] Figure 5 It is a cross-sectional structural diagram of the present invention.

[0030] In the figure: 1. Shell; 101. Shell one; 1011. Heat sink; 1012. Heat sink shell; 1013. Wire outlet hole; 102. Shell two; 1021. Extension block; 103. Shell three; 2. Frameless motor; 201. Motor winding; 202. Rotor; 203. Motor shaft; 3. Harmonic reducer; 301. Steel wheel; 302. Wave generator; 303. Flexible wheel; 4. Flexible component; 401. Flexible ring; 402. Connecting frame; 403. Transmission groove; 404. Fixing hole; 405. Bending part; 5. Servo drive; 6. Encoder; 601. Reading head; 602. Magnetic ring; 7. Output shaft; 701. Hollow shaft; 702. Transmission boss. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and do not constitute a limitation of the present invention.

[0032] like Figure 1 and Figure 2 As shown, a hollow flexible joint module includes a shell 1, an output shaft 7, a frameless motor 2, a harmonic reducer 3 and a flexible component 4 are arranged inside the shell 1, and the output shaft 7 is rotatably connected to the middle part of the shell 1; the frameless motor 2 is arranged at one end of the shell 1; the input end of the harmonic reducer 3 is connected to the output end of the frameless motor 2; the flexible component 4 is connected to the output end of the harmonic reducer 3, and the middle part is connected to the output shaft 7; wherein, the frameless motor 2 drives the output shaft 7 to rotate through the harmonic reducer 3 and the flexible component 4 in turn.

[0033] Specifically, the output shaft 7 is rotatably arranged in the middle of the shell 1, and the frameless motor 2, harmonic reducer 3 and flexible component 4 are arranged in sequence along the axial direction of the output shaft 7 and are all installed on the inner wall of the shell 1. A servo driver 5 is provided on one side of the frameless motor 2. The servo driver 5 is used to drive the frameless motor 2 to generate driving force. The servo driver 5 is installed on the inner wall of the shell 1 and is preferably fixed with screws; the harmonic reducer 3 is fixed on the inner wall of the shell 1, and its input end is connected to the output end of the frameless motor 2. Under the action of the servo driver 5, the frameless motor 2 drives the harmonic reducer 3 to be in a working state, and makes the output end of the harmonic reducer 3 drive the flexible component 4 to rotate, wherein the flexible component 4 can be deformed, and the stiffness belongs to a certain value. The specific stiffness is selected according to different materials. When the flexible component 4 rotates under the drive of the harmonic reducer 3, the middle part is connected to the output shaft 7, and drives the output shaft 7 to rotate through its own deformation, thereby realizing the output of the joint module.

[0034] The frameless motor 2 of the present application is jointly transmitted on the output shaft 7 through the harmonic reducer 3 and the flexible component 4. The flexible component 4 minimizes the damage of the impact of the output shaft 7 to the harmonic reducer 3. On the basis of the flexible component 4, the precise control of the torque is also ensured. At the same time, the flexible component 4 can also temporarily store energy, similar to a spring that can store and release energy, thereby improving energy utilization efficiency.

[0035] like Figure 3 and Figure 4As shown, the flexible assembly 4 includes a flexible ring 401 and a connecting frame 402. The flexible ring 401 is connected to the connecting frame 402. The inner wall of the flexible ring 401 is connected to a curved portion 405. The curved portion 405 can be deformed, and a transmission groove 403 is provided at the center of the flexible ring 401. The transmission groove 403 is connected to the output shaft 7. The connecting frame 402 and the flexible ring 401 are fixed to each other. The connecting frame 402 and the connecting ring are provided with circumferentially arranged fixing holes 404. The connecting frame 402 and the flexible ring 401 are connected by a plurality of fixing holes 404 and fasteners, such as bolts and screws, to achieve tight fixation. The curved portion 405 is connected to the inner wall of the flexible ring 401, preferably integrally formed on the inner wall of the flexible ring 401. The middle part of the flexible ring 401 is provided with a transmission groove 403. The output shaft 7 can be tightly matched with the transmission groove 403 in the form of a spline shaft, so that the rotation of the flexible portion can drive the output shaft 7 to rotate. In addition, the flexible component 4 can also form the flexible ring 401 and the connecting frame 402 as one piece, such as using a vulcanization integration process to enable the connecting frame 402 to realize transmission, and the flexible ring 401 and the connecting frame 402 are fixed as one piece. This method also reduces the deformation occurring at the fixing hole 404, further improving the accuracy of the transmission torque.

[0036] like Figure 4 As shown, in the present application, the curved portion 405 is S-shaped and surrounds the flexible ring 401 as the center. Among them, the curved portion 405 is made of flexible material, and the rigidity value is fixed. Its S-shaped curved portion 405 has more bending and expansion space when subjected to external force. Compared with straight-line or other arc-shaped flexible components, it can produce elastic deformation in multiple directions through its own S-shaped curve, deform along its curved path, thereby absorbing greater energy, buffering external impact, and further reducing the load of the harmonic reducer 3; the S-shaped curved portion 405 acts as a medium for force or torque transmission, and plays a role similar to a buffer zone during transmission, reducing mechanical fatigue caused by impact during power transmission; in addition, the S-shaped curved portion 405 can compensate for manufacturing errors and assembly errors in the mechanical system through its own elastic deformation, and use its elastic deformation to fill these gaps to ensure the continuity and accuracy of power transmission.

[0037] In the present application, a connecting frame 402 is installed on one side of the flexible ring 401 so that the connecting frame 402 fits against one side of the curved portion 405, ensuring that the area of ​​the S-shaped curved portion 405 that fits against the connecting frame 402 is increased as much as possible, thereby limiting the rotation of the curved portion 405 around the axis of the flexible ring 401, reducing its deformation along the axis of the flexible ring 401, and further improving its transmission accuracy and the service life of the curved portion 405.

[0038] The S-shaped bend 405 is a closed serpentine structure evenly distributed within the inner circle of the flexible ring 401. Its inner wall, located near the center of the ring, forms a flexible block with a transmission slot 403. The outer periphery of the flexible block forms the closed serpentine structure. A deformation space exists between the flexible block and the closed serpentine structure. When a heavy load is applied, the flexible block can move from this deformation space and rest on the inner wall of the closed serpentine structure, participating in the flexible transmission. The bend 405 has three sets of compression points, located at the junction of the bend and the flexible ring 401, enabling the S-shaped structure to carry greater torque.

[0039] like Figure 2 and Figure 5 As shown, at least two encoders 6 are disposed inside the housing 1, wherein the two encoders 6 are configured on both sides of the flexible component 4 to obtain different rotational speeds on both sides of the flexible component 4. The encoders 6 are disposed on both sides of the flexible component 4, wherein one encoder 6 is installed between the flexible component 4 and the harmonic reducer 3 to obtain the rotational speed of the flexible component 4 before deformation; the other encoder 6 is disposed between the flexible component 4 and the output end of the output shaft 7 to measure the output angle of the output shaft 7, thereby obtaining the output angle of the output shaft 7 and the harmonic reducer 3. The difference between the two is the deformation angle value of the bending portion 405, and the following relationship is obtained:

[0040] T = k·θ;

[0041] T is the torque acting on the output end of the robot joint module, measured in Newton meters (N·m). k refers to the joint module's ability to resist elastic deformation, namely the stiffness of the curved portion 405, measured in Newton meters / radian (N·m / rad). A greater stiffness indicates a smaller deformation angle of the joint module under the same load torque. θ refers to the angular magnitude of the elastic deformation of the joint module under the load torque, measured in radians (rad). It reflects the degree of deformation of the joint module due to the load.

[0042] The output torque of the output shaft 7 can be obtained through the above formula, and torque closed-loop control can be performed without the need for additional torque sensors. At the same time, the accuracy of joint motion control is improved, ensuring the integration of the joint module.

[0043] like Figure 5As shown, the frameless motor 2 includes a motor winding 201 and a rotor 202 that cooperate with each other. The motor winding 201 is connected to the housing 1, and the inner ring of the rotor 202 is connected to the motor shaft 203. One end of the motor shaft 203 is connected to the input end of the harmonic reducer 3, wherein the output shaft of the frameless motor 2 is in its inner ring, that is, the rotor 202 of the present application. The inner ring of the rotor 202 is tightly connected to the motor shaft 203, such as fixed by structural adhesive, or fixed by splines, screws, etc. One end of the motor shaft 203 close to the frameless motor 2 is abutted against one end of the output shaft body 7 through a bearing, and the other end is installed on the input end of the harmonic reducer 3 through a bearing to achieve the limitation of the motor shaft 203 and stabilize the motor shaft 203 to transmit power through the frameless motor 2. An encoder 6 is also installed between the harmonic reducer 3 and the servo driver 5 to measure the output angle of the frameless motor 2. The two encoders 6 before and after the harmonic reducer 3 can be used to infer whether the harmonic reducer 3 is deformed.

[0044] like Figure 2 and Figure 5 As shown, the harmonic reducer 3 includes a steel wheel 301, a flexspline 303, and a wave generator 302 that cooperate in sequence. The steel wheel 301 is connected to the inner wall of the housing 1, the wave generator 302 is connected to the motor shaft 203, the flexspline 303 meshes with the steel wheel 301, and one side of the flexspline 303 is connected to the connecting frame 402. The steel wheel 301 abuts against the inner wall of the housing 1, and the wave generator 302 is fixed to the motor shaft 203, so that the motor shaft 203 drives the wave generator 302 to rotate, and the wave generator 302 drives the flexspline 303 to mesh with the steel wheel 301. A plurality of screws or bolts are used to tighten one side of the flexspline 303 and the connecting frame 402 to synchronously drive the flexible ring 401 and the curved portion 405 to rotate, thereby achieving rotational output of the output shaft 7. Among them, a circular groove for accommodating the curved portion 405 is opened on the locking side of the connecting frame 402. The circular groove can guide the deformation direction of the curved portion 405 to avoid irregular twisting or bending of the curved portion 405. At the same time, it can also reduce the swing and shaking of the joint when bearing load, thereby improving the positioning accuracy and movement stability of the robot joint. The encoder 6 between the harmonic reducer 3 and the frameless motor 2 is installed on the steel wheel 301 or the extension frame of the steel wheel 301, and the other is installed on the motor shaft 203.

[0045] like Figure 1 、 Figure 2 and Figure 5As shown, the housing 1 includes a housing 1 101, a housing 2 102, and a housing 3 103. The housings 101, 102, and 103 are connected in sequence and combined to form a housing 1 with a cavity. The housing 2 102 is a hollow cylinder, with its two ends connected to the housing 1 101 and the housing 3 103, respectively, and secured with screws to ensure that the two ends of the output shaft 7 are exposed from the housing 1 101 and the housing 3 103, respectively, to facilitate the provision of driving force. In addition, the housing 1 can also be formed of two independent assembled housings, with the two assembled housings locked and secured on their facing sides to form the shape of the present application.

[0046] In the present application, the housing 1 is preferably assembled by using a housing 1 101, a housing 2 102 and a housing 3 103. The inner wall of the housing 2 102 protrudes to form an extension block 1021. One of the encoders 6 is configured on the side of the extension block 1021 facing the flexible component 4 to ensure the positional assembly relationship between the encoder 6 and the housing 2 102, which is also convenient for pre-installation and improves the compactness of the structure. The extension block 1021 is integrally formed with the housing 2 102, and one side of the flexible wheel 303 of the harmonic reducer 3 extends to the ring formed by the extension block 1021. In the groove, the middle part of the connecting frame 402 extends toward the middle part of the extension block 1021, and fits and locks with the middle part of the flexible wheel 303, preferably using bolts, screws, etc. to lock and fix. The inner ring of the connecting frame 402 uses a bearing to lean against the outer wall of the output shaft body 7 to improve the support effect of the output shaft body 7 to avoid uneven force caused by the excessive length of the output shaft body 7. A bearing is also provided between the extension block 1021 and the connecting frame 402, preferably a thin-walled ball bearing, to reduce the occupied space and further improve the close fit between the connecting frame 402 and the extension block 1021.

[0047] In the present application, shell one 101 and shell three 103 are respectively installed at the two ends of shell two 102 in a concave-convex manner and are fixed with screws to ensure coaxiality. Shell one 101 includes a heat dissipation shell 1012 and a plurality of heat dissipation fins 1011 circumferentially arranged on the outer wall of the heat dissipation shell 1012. The heat dissipation shell 1012 and the end of shell two 102 are assembled with a concave-convex structure. The frameless motor 2 is installed on the inner wall of shell one 101 to improve the heat dissipation efficiency of the frameless motor 2. At the same time, the outer shell 1 serves as the shell of the frameless motor 2, further improving the simplicity of the structure. A wire outlet hole 1013 is opened on the heat dissipation shell 1012 to facilitate the placement of the cables of the servo drive 5.

[0048] like Figures 3 to 5As shown, the encoder 6 adopts an absolute position magnetic encoder, which can better control the start and stop of the frameless motor 2, and no direction calibration is required after power-off startup. The encoder 6 includes a reading head 601 and a magnetic ring 602, and the reading head 601 and the magnetic ring 602 are respectively connected to the side walls facing the extension block 1021 and the connecting frame 402, wherein the reading head 601 is embedded in one side of the extension block 1021, and the magnetic ring 602 is embedded and installed in the connecting frame 402, which ensures the concentricity of the magnetic ring 602 and the reading head 601, and further reduces the length occupied by the two in the cavity of the shell 1, thereby improving the integration and measurement accuracy.

[0049] like Figure 2 and Figure 5 As shown, the output shaft body 7 includes a hollow shaft 701 and a transmission boss 702. The hollow shaft 701 passes through the middle of the housing 1, with one end connected to the inner ring of the bearing at the end of the motor shaft 203. The middle of the hollow shaft 701 is connected to the inner ring of the bearing on the inner wall of the connecting frame 402 to achieve transmission stability. A bearing is installed between the other end of the hollow shaft 701 and the housing 3 103 to ensure that the hollow shaft 701 remains stable during transmission. The transmission boss 702 is set on the outer wall of the hollow shaft 701 and is compatible with the transmission groove 403 opened by the curved portion 405. Preferably, the transmission boss 702 is integrally formed on the outer wall of the hollow shaft 701. The hollow shaft 701 is provided with an output threaded hole for outputting torque. The hollow shaft 701 and the curved portion 405 are matched through the circumferential transmission boss 702 to achieve power transmission. The design of the hollow shaft 701 can be used for wiring, improving space utilization efficiency. Housing 3 103 mates with housing 2 102 via a shoulder, creating a concave-convex structure that ensures coaxiality at the output end. Housing 3 103 is secured to housing 2 102 via screws through its tapered countersunk holes. The joint module is mounted to the robot through threaded holes in housing 3 103.

[0050] The output shaft 7 of the present application adopts a double-end support feature design, that is, a multi-point bearing support structure, which improves the stiffness of the joint and avoids the low stiffness problem caused by single-end cantilever support when used in the robot.

[0051] A legged robot, wherein the hollow flexible joint module mentioned above is installed at at least one joint of the legged robot. When the leg of the legged robot touches the ground, the flexible component 4 acts as a buffer and can store energy; when the leg of the legged robot lifts its leg, the flexible component 4 releases the stored energy, thereby improving the energy utilization efficiency of the robot. At the same time, considering that the harmonic reducer 3 will produce a certain degree of flexible deformation when subjected to load, two encoders 6 are arranged on both sides of the flexible component 4 with a certain stiffness. The difference in the measured angle value is the deformation angle of the flexible component 4, thereby accurately obtaining the load size and output end angle of the flexible joint module, and torque closed-loop control can be performed without the need for additional torque sensors, while improving the accuracy of joint motion control.

[0052] The following describes the working process of a hollow robot flexible joint module. The specific method is as follows:

[0053] When the joint module of the legged robot outputs torque, the joint module is powered on, and the servo driver 5 controls the motor winding 201 to generate a rotating magnetic field, which drives the rotor 202 to rotate and output torque. The rotor 202 is fixedly connected to the motor shaft 203 and drives the motor shaft 203 to rotate. The motor shaft 203 is fixedly connected to the wave generator 302 of the harmonic reducer 3, and the torque and rotational motion are input to the harmonic reducer 3. The torque is amplified by the harmonic reducer 3 and output to the connecting frame 402, and the S-shaped curved portion 405 is compressed, generating elastic deformation. The deformation generates torque, which is transmitted to the hollow shaft 701 through the circumferential transmission groove 403. The final output torque transmits power outward through the threaded hole on the hollow shaft 701.

[0054] When the joint module is subjected to impact load torque during movement, the impact load torque will act on the hollow shaft 701 through the output threaded hole, and the circumferential transmission boss 702 will transmit the impact load torque from the output hollow shaft 701 to the bending part 405, causing the S-shaped bending part 405 to be compressed and produce elastic deformation. At this time, the flexible characteristic element acts as a spring, which can provide buffering and prevent destructive effects on the harmonic reducer 3.

[0055] Since the stiffness of the bending part 405 is constant, the difference in the angle values ​​of the flexible component 4 is measured by the encoders 6 on both sides thereof, and the load torque received by the flexible component 4 can be obtained. The load torque received by the flexible component 4 is the load torque received by the joint module. Therefore, the load torque at the output end of the joint module can be accurately measured without adding a torque sensor, thereby reducing the components of the joint module, reducing the volume of the joint module, and improving the integration of the joint module.

[0056] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A hollow flexible joint module, comprising a housing (1), characterized in that: The interior of the housing (1) is provided with: an output shaft (7) rotatably connected to the middle portion of the housing (1); a frameless motor (2) disposed at one end of the housing (1); a harmonic reducer (3), the input end of which is connected to the output end of the frameless motor (2); and A flexible component (4) connected to the output end of the harmonic reducer (3), and the middle portion of the flexible component (4) is connected to the output shaft (7); The frameless motor (2) drives the output shaft (7) to rotate via the harmonic reducer (3) and the flexible component (4) in sequence.

2. The hollow flexible joint module according to claim 1, characterized in that: The flexible component (4) comprises a flexible ring (401) and a connecting frame (402), wherein the flexible ring (401) is connected to the connecting frame (402), and the inner wall of the flexible ring (401) is connected to a curved portion (405), wherein the curved portion (405) is deformable, and a transmission groove (403) is provided at the center of the curved portion (405) of the flexible ring (401), and the transmission groove (403) is connected to the output shaft (7).

3. The hollow flexible joint module according to claim 2, characterized in that: The curved portion (405) is arranged in an S-shape with the flexible ring (401) as the center.

4. The hollow flexible joint module according to claim 2, wherein: At least two encoders (6) are disposed inside the housing (1), wherein the two encoders (6) are arranged on both sides of the flexible component (4) to obtain different rotational speeds on both sides of the flexible component (4).

5. The hollow flexible joint module according to claim 2, characterized in that: The frameless motor (2) comprises a motor winding (201) and a rotor (202) that cooperate with each other, the motor winding (201) being connected to the housing (1), the inner ring of the rotor (202) being connected to a motor shaft (203), and one end of the motor shaft (203) being connected to an input end of the harmonic reducer (3).

6. The hollow flexible joint module according to claim 5, characterized in that: The harmonic reducer (3) comprises a steel wheel (301), a flexible wheel (303) and a wave generator (302) which are matched in sequence, wherein the steel wheel (301) is connected to the inner wall of the housing (1), the wave generator (302) is connected to the motor shaft (203), the flexible wheel (303) is meshed with the steel wheel (301), and one side of the flexible wheel (303) is connected to the connecting frame (402).

7. The hollow flexible joint module according to claim 4, characterized in that: The housing (1) comprises a housing 1 (101), a housing 2 (102) and a housing 3 (103); the housing 1 (101), the housing 2 (102) and the housing 3 (103) are sequentially connected and combined to form a housing (1) with a cavity.

8. The hollow flexible joint module according to claim 7, characterized in that: The inner wall of the second housing (102) protrudes to form an extension block (1021), wherein one of the encoders (6) is arranged on a side of the extension block (1021) facing the flexible component (4).

9. The hollow flexible joint module according to claim 8, characterized in that: The encoder (6) comprises a reading head (601) and a magnetic ring (602), wherein the reading head (601) and the magnetic ring (602) are respectively connected to one side wall of the extension block (1021) and the connecting frame (402) facing each other.

10. A legged robot, characterized in that: The hollow flexible joint module according to any one of claims 1 to 9 is installed at at least one joint of the legged robot.

Images