Harmonic reducer integrated with torque sensor

Abstract

The utility model provides a kind of harmonic reducer of integrated torque sensor belongs to robot technical field.It solves the problem such as insufficient accuracy of existing harmonic reducer force feedback.The harmonic reducer of integrated torque sensor, including main bearing, wave generator and output shaft, the outer peripheral side of wave generator is equipped with flexible bearing, flexible bearing is equipped with flexible gear, the outer peripheral side of flexible gear is equipped with rigid gear, rigid gear and flexible gear difference tooth engagement, output shaft is set in wave generator, first bearing is arranged between output shaft and wave generator, main bearing is located in the side of rigid gear and rigid gear and the outer ring of main bearing fixed connection, the inner peripheral surface of the inner ring of main bearing is integrally provided with the main disc of torque sensor, the main disc of torque sensor, the output end of flexible gear and output shaft fixed connection.The harmonic reducer of integrated torque sensor improves the accuracy of force feedback.

Description

Technical Field

[0001] This utility model belongs to the field of robot technology and relates to a harmonic reducer. Background Technology

[0002] The finger joints of a humanoid robot include linear joints and rotary joints. Linear joints use linear actuators, while rotary joints use rotary actuators. The drive source for rotary joints is a frameless motor, which often requires speed reduction during output. Harmonic reducers are a suitable type of reducer.

[0003] For example, Chinese patent literature discloses a hollow harmonic reducer (publication number CN102734392A), which includes a harmonic reducer body. A connecting shaft is located within the reducer body. A wave generator is connected to the working end of the connecting shaft via fasteners. A through hole is formed on the connecting shaft, communicating with a circular hole on the wave generator. A thread is provided on the output end of the connecting shaft. During operation, a motor drives the connecting shaft to rotate, and the wave generator drives a flexible gear to mesh with a rigid gear. Finally, the reduced motion is output from the harmonic reducer body.

[0004] Currently, torque sensors are generally installed at the input end of the motor shaft to indirectly calculate the load torque at the output end of the harmonic reducer by detecting the motor's output torque. The torque sensor includes a main disc and strain gauges fixed on the main disc, such as the torque sensor flange and torque sensor disclosed in Chinese patent literature (announcement number: CN220505620U), where the torque sensor flange is the main disc. However, the harmonic reducer experiences transmission through a flexible wheel and a rigid wheel from the input to the output, resulting in interference from inertia and friction. This often leads to inaccurate calculations of the load torque at the harmonic reducer's output, resulting in insufficient accuracy in force feedback. Utility Model Content

[0005] The purpose of this invention is to address the aforementioned problems in the existing technology by proposing a harmonic reducer with an integrated torque sensor, and to solve the technical problem of how to improve the accuracy of force feedback in the harmonic reducer.

[0006] The objective of this utility model can be achieved through the following technical solutions:

[0007] A harmonic reducer with an integrated torque sensor includes a main bearing and a wave generator. A flexible bearing is fitted on the outer periphery of the wave generator, a flexible wheel is fitted on the flexible bearing, and a rigid wheel is fitted on the outer periphery of the flexible wheel. The rigid wheel and the flexible wheel mesh with differential teeth. The reducer is characterized by further including an output shaft, which passes through the wave generator. A first bearing is provided between the output shaft and the wave generator. The main bearing is located on one side of the rigid wheel, and the rigid wheel is fixedly connected to the outer ring of the main bearing. A main body disk of a torque sensor is integrally formed on the inner circumferential surface of the inner ring of the main bearing. The main body disk of the torque sensor, the output end of the flexible wheel, and the output shaft are fixedly connected.

[0008] The wave generator is connected to the motor. The rotation of the wave generator drives a flexible wheel via a flexible bearing, which meshes with the rigid wheel. Since the main body of the torque sensor, the output end of the flexible wheel, and the output shaft are fixedly connected, the flexible wheel drives the output shaft and the main body of the torque sensor (i.e., the inner ring of the main bearing) to rotate. Finally, the power is output from the inner ring of the main bearing. The main body of the torque sensor is integrally mounted on the inner ring of the main bearing. The torque sensor directly detects the load torque of the inner ring of the main bearing, avoiding errors from indirect measurement and calculation, as well as interference from inertia and friction during the transmission between the flexible wheel and the rigid wheel, thus improving the accuracy of the force feedback of the harmonic reducer. Furthermore, the main body of the torque sensor is integrally mounted on the inner circumference of the inner ring of the main bearing, allowing the main bearing to withstand the high torque caused by instantaneous impacts (such as a robot falling or sudden loads), preventing damage to the torque sensor due to instantaneous impacts and ensuring the accuracy of the force feedback of the harmonic reducer. Furthermore, the output shaft is supported on the wave generator via the first bearing. The assembly, consisting of the output shaft, flexure, and torque sensor main body disk, is fixedly connected, forming two support points through the main bearing and the first bearing. This not only ensures stable rotation of the output shaft, flexure, and torque sensor main body disk but also reduces the impact of output shaft bending on the torque sensor. Therefore, this harmonic reducer with integrated torque sensor improves the accuracy of force feedback.

[0009] In the aforementioned harmonic reducer with an integrated torque sensor, the main body of the torque sensor includes an inner ring and strain beams integrally connected to the outer circumferential surface of the inner ring. Several strain beams are evenly arranged circumferentially, and each strain beam has a deformation groove. A protruding connecting disc is located on the outer circumferential surface of the output shaft. A fixed disc is located at the output end of the flex wheel, between the inner ring and the connecting disc, and the inner ring, fixed disc, and connecting disc are fixedly connected by bolts. This reduces interference from the flex wheel to the strain beams, ensuring accurate torque sensor detection. Furthermore, it allows for a compact structure in the harmonic reducer, facilitating its lightweight and miniaturized design.

[0010] In the aforementioned harmonic reducer with an integrated torque sensor, the inner ring is fitted onto the output shaft, and the inner circumferential surface of the inner ring abuts against the outer circumferential surface of the output shaft. The output shaft supports the torque sensor main body disk, ensuring stable operation of the torque sensor main body disk and improving the accuracy of the force feedback of the harmonic reducer.

[0011] In the aforementioned harmonic reducer with integrated torque sensor, an end cap is fixedly connected to the other side of the rigid wheel. The end cap is fitted onto the wave generator and a second bearing is provided between the end cap and the wave generator.

[0012] The wave generator is supported on the end cover, ensuring stable rotation and reducing transmission errors, thus ensuring stable operation of the harmonic reducer. Furthermore, the wave generator is supported on the end cover via a second bearing, while the output shaft is supported on the wave generator via a first bearing. The torque sensor main body is fixed to the output shaft. This arrangement further stabilizes the output shaft and the torque sensor main body, and also improves the accuracy of the force feedback in the harmonic reducer.

[0013] In the aforementioned harmonic reducer with an integrated torque sensor, sealing rings are provided between the end cover and the rigid wheel, and between the rigid wheel and the outer ring of the main bearing. These sealing rings prevent external impurities from entering the harmonic reducer through the gaps between the end cover and the rigid wheel, and between the rigid wheel and the outer ring of the main bearing, thus ensuring stable operation of the harmonic reducer.

[0014] In the aforementioned harmonic reducer with integrated torque sensor, an oil seal is provided between the inner and outer rings of the main bearing.

[0015] Oil seals protect the rollers of the main bearing, preventing external impurities from contacting them and preventing lubricating grease from leaking out, thus ensuring smooth operation of the rollers.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The main body of the torque sensor is integrally mounted on the inner ring of the main bearing. A first bearing is installed between the output shaft and the wave generator. The water outlet of the flexible wheel, the main body of the torque sensor, and the output shaft are fixedly connected, which improves the accuracy, real-time response, and reliability of the force feedback of the harmonic reducer. Attached Figure Description

[0018] Figure 1 This is a 3D view of the harmonic reducer with integrated torque sensor.

[0019] Figure 2 This is a cross-sectional view of the harmonic reducer with integrated torque sensor.

[0020] Figure 3This is a 3D view of the inner ring of the main bearing in the harmonic reducer with integrated torque sensor.

[0021] In the diagram, 1. Main bearing; 1a. Inner ring; 1a1. Main body disc; 1a1a. Inner ring; 1a1b. Strain beam; 1a1c. Deformation groove; 1b. Outer ring; 1c. Oil seal; 2. Wave generator; 2a. Wave generating cam; 3. Flexible bearing; 4. Flexible wheel; 4a. Fixed disc; 5. End cover; 6. Rigid wheel; 7. Output shaft; 7a. Connecting disc; 8. First bearing; 9. Bolt; 10. Second bearing; 11. Sealing ring; 12. Cover plate. Detailed Implementation

[0022] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0023] like Figure 1 and Figure 2 As shown, a harmonic reducer with an integrated torque sensor includes a main bearing 1, a wave generator 2, and an output shaft 7. The main bearing 1 is a crossed roller bearing. The wave generator 2 is a hollow shaft with a wave-generating cam 2a at its inner end. A flexible bearing 3 is mounted on the outer periphery of the wave-generating cam 2a, and a flexible wheel 4 is mounted on the flexible bearing 3. A rigid wheel 6 is mounted on the outer periphery of the flexible wheel 4, and the rigid wheel 6 meshes with the flexible wheel 4 with differential teeth. The rigid wheel 6 has more teeth than the flexible wheel 4; typically, the rigid wheel 6 has two more teeth than the flexible wheel 4. For example, if the rigid wheel 6 has 200 teeth, the flexible wheel 4 has 198 teeth. The output shaft 7 passes through the wave generator 2, and a first bearing 8 is provided between the output shaft 7 and the wave generator 2. The outer circumferential surface of the output shaft 7 has a protruding connecting disk 7a. The main bearing 1 is located on one side of the rigid wheel 6 and the rigid wheel 6 is fixedly connected to the outer ring 1b of the main bearing 1. The main body disk 1a1 of the torque sensor is integrally provided on the inner circumferential surface of the inner ring 1a of the main bearing 1. The main body disk 1a1 of the torque sensor, the output end of the flexible wheel 4 and the connecting disk 7a are fixedly connected.

[0024] like Figure 2 and Figure 3As shown, the main body disk 1a1 of the torque sensor includes an inner ring 1a1a and a strain beam 1a1b integrally connected to the outer circumferential surface of the inner ring 1a1a. Several strain beams 1a1b are evenly arranged circumferentially, and deformation grooves 1a1c are provided on the strain beams 1a1b. The strain gauges of the torque sensor are fixed within the deformation grooves 1a1c. The output end of the flexible wheel 4 has a fixed disk 4a, located between the inner ring 1a1a and the connecting disk 7a. The inner ring 1a1a, the fixed disk 4a, and the connecting disk 7a are fixedly connected by bolts 9. The inner ring 1a1a is fitted onto the output shaft 7, and the inner circumferential surface of the inner ring 1a1a abuts against the outer circumferential surface of the output shaft 7. An end cap 5 is also fixedly connected to the other side of the rigid wheel 6. The end cap 5 is fitted onto the wave generator 2, and a second bearing 10 is provided between the end cap 5 and the wave generator 2. The outer end of the wave generator 2 extends beyond the end cap 5. A sealing ring 11 is provided between the end cover 5 and the rigid wheel 6, and between the rigid wheel 6 and the outer ring 1b of the main bearing 1. An oil seal 1c is provided between the inner ring 1a and the outer ring 1b of the main bearing 1, and the oil seal 1c is located on the outer end of the main bearing 1. A cover plate 12 is fixedly connected to the outer end of the torque sensor main body disk 1a1, and the cover plate 12 can reduce electromagnetic interference.

[0025] The outer end of the wave generator 2 is connected to the motor. The rotation of the wave generator 2 drives the flexible wheel 4 to mesh with the rigid wheel 6 through the flexible bearing 3. Since the main body disk 1a1 of the torque sensor, the fixed disk 4a and the connecting disk 7a of the flexible wheel 4 are fixedly connected, the flexible wheel 4 drives the output shaft 7 and the main body disk 1a1 of the torque sensor (i.e. the inner ring 1a of the main bearing 1) to rotate. Finally, the power is output by the inner ring 1a of the main bearing 1. The main body disk 1a1 of the torque sensor is integrally set on the inner ring 1a of the main bearing 1. The torque sensor is used to directly detect the load torque of the inner ring 1a of the main bearing 1. This not only avoids the errors of indirect measurement and calculation derivation, but also avoids the interference of motion inertia and friction when the flexible wheel 4 and the rigid wheel 6 are driven, thus improving the accuracy of the force feedback of the harmonic reducer. Furthermore, the main body disk 1a1 of the torque sensor is integrally mounted on the inner circumferential surface of the inner ring 1a of the main bearing 1. The main bearing 1 bears the high torque caused by instantaneous impacts (such as a robot falling or sudden loads), preventing damage to the torque sensor due to such impacts and ensuring the accuracy of the force feedback from the harmonic reducer. Therefore, this harmonic reducer with integrated torque sensor improves the accuracy of force feedback.

[0026] The torque sensor, integrated with the crossed roller bearing, makes the harmonic reducer compact and reduces costs. Furthermore, instantaneous impacts of several times the rated torque (such as robot falls or sudden loads) act directly on the high-load crossed roller bearing, thus preventing damage to the torque sensor. The torque sensor uses strain gauge sensing technology, has no mechanically worn parts, and boasts a lifespan of millions of cycles. This harmonic reducer with integrated torque sensor can accurately measure minute torque changes at the joint ends (resolution below 0.1% FS), making it suitable for force-sensitive applications such as precision assembly and medical surgery. The torque sensor's sampling frequency is as high as 1 kHz - 10 kHz, capturing instantaneous changes in joint torque in real time, meeting the control requirements of high-speed motion or sudden load changes. This harmonic reducer can also be used for collision detection, identifying unexpected collisions (such as in human-machine collaboration scenarios) through torque surges, triggering emergency stops or avoidance maneuvers to ensure the safety of personnel and equipment. This harmonic reducer can be used to achieve adaptive compliant control: combined with impedance / admittance control algorithms, it enables "soft landing" of joints or dynamic force following (such as polishing and screw tightening), improving adaptability to complex tasks. It can also realize one-handed drag-and-drop programming applications. Through precise force feedback, real-time response, and high reliability, this harmonic reducer achieves a leap from "blind operation" to "intelligent tactile feedback," thereby enabling: 1. Precision assembly and polishing: compensating for machining errors through force control; 2. Collaborative robots (Cobot): providing safe tactile feedback during human-machine interaction; 3. Exoskeletons / rehabilitation robots: dynamically adjusting joint assistance according to human movement intentions.

[0027] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A harmonic reducer with an integrated torque sensor, comprising a main bearing (1) and a wave generator (2), wherein a flexible bearing (3) is fitted on the outer periphery of the wave generator (2), a flexible wheel (4) is fitted on the flexible bearing (3), and a rigid wheel (6) is fitted on the outer periphery of the flexible wheel (4), wherein the rigid wheel (6) and the flexible wheel (4) are engaged by differential gear meshing, characterized in that, It also includes an output shaft (7), which passes through the wave generator (2). A first bearing (8) is provided between the output shaft (7) and the wave generator (2). The main bearing (1) is located on one side of the rigid wheel (6) and the rigid wheel (6) is fixedly connected to the outer ring (1b) of the main bearing (1). The main body disk (1a1) of the torque sensor is integrally provided on the inner circumferential surface of the inner ring (1a) of the main bearing (1). The main body disk (1a1) of the torque sensor, the output end of the flexible wheel (4), and the output shaft (7) are fixedly connected.

2. The harmonic reducer with integrated torque sensor according to claim 1, characterized in that, The main body disk (1a1) of the torque sensor includes an inner ring (1a1a) and a strain beam (1a1b) integrally connected to the outer circumferential surface of the inner ring (1a1a). There are several strain beams (1a1b) and they are evenly arranged in the circumferential direction. A deformation groove (1a1c) is provided on the strain beam (1a1b). The outer circumferential surface of the output shaft (7) has a protruding connecting disk (7a). The output end of the flexible wheel (4) has a fixed disk (4a). The fixed disk (4a) is located between the inner ring (1a1a) and the connecting disk (7a), and the inner ring (1a1a), the fixed disk (4a) and the connecting disk (7a) are fixedly connected by bolts (9).

3. The harmonic reducer with integrated torque sensor according to claim 2, characterized in that, The inner ring (1a1a) is fitted onto the output shaft (7), and the inner circumferential surface of the inner ring (1a1a) is in contact with the outer circumferential surface of the output shaft (7).

4. The harmonic reducer with an integrated torque sensor according to any one of claims 1-3, characterized in that, An end cap (5) is fixedly connected to the other side of the rigid wheel (6). The end cap (5) is fitted onto the wave generator (2) and a second bearing (10) is provided between the end cap (5) and the wave generator (2).

5. The harmonic reducer with an integrated torque sensor according to claim 4, characterized in that, A sealing ring (11) is provided between the end cap (5) and the rigid wheel (6) and between the rigid wheel (6) and the outer ring (1b) of the main bearing (1).

6. The harmonic reducer with an integrated torque sensor according to any one of claims 1-3, characterized in that, An oil seal (1c) is provided between the inner ring (1a) and the outer ring (1b) of the main bearing (1).

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