Harmonic speed reducer with torsion limiting function

Abstract

The invention provides a harmonic speed reducer with torsion limitation, and relates to the technical field of speed reducers, the harmonic speed reducer comprises a wave generator and a torsion limiter, the wave generator is connected with a flexible gear, and the flexible gear is meshed with a rigid gear; the torsion limiter is composed of an inner hole shaft and a flexible gear connecting ring, and the inner hole shaft and the flexible gear connecting ring are dynamically coupled through balls and meshing ball positions. When the torque exceeds the preset upper limit, the balls are separated from the inner hole shaft, and mechanical decoupling of the flexible gear and the connecting shaft is achieved. The harmonic speed reducer has the beneficial effects that when the harmonic speed reducer is abnormally overloaded or impacted, the torsion limiter forces the flexible gear to be disconnected from the connecting shaft, so that the permanent deformation of the tooth shape of the flexible gear, the clamping stagnation of a flexible gear bearing of a wave generator and other mechanical damages caused by mechanical impact are avoided, and a winding of a driving motor connected with the flexible gear is also prevented from being overloaded and burnt; and impact load accumulation can be avoided through instantaneous separation of the connecting parts, so that overload protection is achieved for mechanical equipment, and the safety of the collaborative robot and the humanoid robot can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of reducers, in particular to a harmonic reducer with torque limitation. Background Art

[0002] The harmonic reducer is a high-precision transmission device based on the principle of elastic deformation. Its core structure consists of three key components: a rigid wheel, a flexible wheel, and a wave generator. The rigid wheel is a rigid internal gear, and the flexible wheel is an elastic external gear made of high-strength thin-walled alloy material. The two form a meshing basis through the difference in the number of teeth (usually 2 teeth). The wave generator, as a power input component, forces the flexible wheel to undergo periodic elastic deformation through the cooperation of an elliptical cam and a flexible bearing, thereby achieving dynamic adjustment of the tooth surface contact area.

[0003] During operation, the rotation of the wave generator drives the flexspline to produce radial deformation, so that the flexspline teeth and the rigid wheel teeth are meshed in the long axis area of ​​the ellipse, and the short axis area is out of contact. This periodic deformation causes relative movement between the flexspline and the rigid wheel, and the deceleration effect is achieved through the difference in the number of teeth. The single-stage transmission ratio can reach 70-320, and the multi-stage combination can achieve an ultra-large speed ratio of more than 30,000.

[0004] The core advantages of this device are: ① high transmission accuracy (the error is only 1 / 4 of that of ordinary gears), thanks to the error equalization effect of multiple teeth meshing at the same time; ② high torque density per unit volume, and the load-bearing capacity can reach 2-3 times that of traditional structures; ③ zero backlash characteristics, achieving gapless meshing through pre-deformation, which is particularly suitable for precision positioning scenarios; ④ compact structure, compared with the reducer of the same specification, the volume is reduced by more than 30%, and the weight is reduced by about 50%.

[0005] In industrial applications, harmonic reducers have become the core components of industrial robot joint drives and are widely used in precision motion control fields such as six-axis robotic arms and collaborative robots. At the same time, their high reliability and lightweight characteristics also make them play an important role in aerospace servo mechanisms, medical surgical robots and high-end CNC equipment. The latest technological development focuses on improving fatigue life. Through surface strengthening treatment and topology optimization design, the service life has been increased to more than 10,000 hours.

[0006] During the operation of industrial equipment, harmonic reducers, as precision transmission mechanisms, are often threatened by sudden impact loads. Since the reducer flexible wheel assembly adopts a high-strength thin-walled alloy structure, when the equipment's moving joints are subjected to abnormal collisions, the instantaneous peak torque generated will directly act on the reducer's core components through the rigid wheel gear ring. This mechanical impact will not only cause mechanical damage such as permanent deformation of the flexible wheel tooth shape and jamming of the wave generator bearing, but will also cause the drive motor winding to overload and burn out through the power transmission path.

[0007] The technical content disclosed in the Chinese patent document (publication number: CN220622645U, patent name: harmonic reducer) is: the harmonic reducer includes a flexible wheel, a wave generator and a rigid wheel. The surface hardness of the first nitriding layer provided on the surface of the flexible wheel is 550HV to 750HV, which makes the flexible wheel have better wear resistance, the first tooth portion and the first inner hole have better wear resistance, reduce the amount of wear when meshing with the second tooth portion of the rigid wheel, and increase the service life of the flexible wheel. The surface hardness of the first nitriding layer of the rigid wheel is 450HV to 650HV, which makes the rigid wheel have certain strength and wear resistance. The hardness of the first nitriding layer is greater than that of the second nitriding layer, which can effectively improve the wear of the flexible wheel, increase the service life of the flexible wheel, and reduce the replacement frequency; the cost of replacing the rigid wheel is lower than the cost of replacing the flexible wheel, so the use cost of the harmonic reducer can be reduced.

[0008] It can be seen from the above implementation plan and the corresponding drawings that the harmonic reducer only improves the service life of the reducer by increasing the wear resistance of the flexible wheel and the rigid wheel, and does not involve the overload protection mechanism of the power transmission chain. When the equipment encounters an abnormal collision, the instantaneous impact torque will still directly act on the flexible wheel thin-wall structure through the rigid transmission path. Summary of the invention

[0009] The present invention overcomes the shortcomings of the prior art and provides a harmonic reducer with torque limitation. A torque limiter is arranged. When the harmonic reducer is abnormally overloaded or impacted, the torque limiter forces the connection between the flexible wheel and the connecting shaft to be disconnected, so that the flexible wheel will not be reversely braked by the connecting shaft, thereby avoiding mechanical damage such as permanent deformation of the flexible wheel tooth shape and jamming of the flexible wheel bearing of the wave generator caused by mechanical impact, and also avoiding overload and burning of the drive motor winding connected to the flexible wheel. The accumulation of impact loads can also be avoided by instantaneous separation of the connecting parts, thereby providing overload protection for the mechanical equipment and increasing the safety of the collaborative robot and the humanoid robot.

[0010] A torque-limited harmonic reducer comprises a wave generator and a torque limiter, wherein the wave generator is connected to a flexible wheel, and the flexible wheel is meshed with a rigid wheel; The torque limiter is composed of an inner hole shaft and a flexible wheel connecting ring, and the two are dynamically coupled through balls and meshing ball positions; The flexible wheel is connected to the flexible wheel connecting ring, and the inner hole shaft is connected to the connecting shaft; the inner hole shaft and the flexible wheel connecting ring are movably connected; When the torque exceeds the preset upper limit, the ball disengages from the inner hole shaft, achieving mechanical decoupling of the flexible wheel and the connecting shaft.

[0011] Furthermore, a first meshing ball position is radially extended on the outer circumference of the inner hole shaft, and a second meshing ball position is provided at the bottom surface of the flexible wheel connecting ring. The first meshing ball position and the second meshing ball position form an angle, and the ball is clamped in the angle formed by the first meshing ball position and the second meshing ball position.

[0012] Furthermore, a stripping ring is provided on the side of the ball facing away from the first meshing ball position and the second meshing ball position, and the inner circumferential surface of the stripping ring generates a radial restraining force through elastic deformation, so that the ball maintains two-way contact and cooperation with the first meshing ball position and the second meshing ball position; the line connecting the annular contact surface of the stripping ring and the center of the ball is in a complementary geometric relationship with the pressure angle formed by the first meshing ball position and the second meshing ball position.

[0013] Furthermore, the wave generator includes a camshaft and a flexspline bearing.

[0014] Furthermore, the connecting shaft is connected to the cross roller bearing, the cross roller bearing is connected to the adapter plate, and the adapter plate is connected to the rigid wheel.

[0015] Compared with the prior art, the present invention has the following beneficial effects: A harmonic reducer with torque limitation is provided, in which a torque limiter is arranged. When the harmonic reducer is abnormally overloaded or impacted, the torque limiter forces the connection between the flexible wheel and the connecting shaft to be disconnected, so that the flexible wheel will not be reversely braked by the connecting shaft, thereby avoiding mechanical damage such as permanent deformation of the flexible wheel tooth shape and stagnation of the flexible wheel bearing of the wave generator caused by mechanical impact, and avoiding overload and burning of the drive motor winding connected to the flexible wheel. The instantaneous separation of the connecting parts can also avoid the accumulation of impact loads, thereby providing overload protection for mechanical equipment, and increasing the safety of collaborative robots and humanoid robots. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide a further understanding of the present invention and are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 1 is a general schematic diagram of a harmonic reducer according to an embodiment of the present invention; Figure 2 is a first cross-sectional view of a harmonic reducer according to an embodiment of the present invention; Figure 3 is a second cross-sectional view of the harmonic reducer according to an embodiment of the present invention; Figure 4 is a schematic diagram of an explosion of a harmonic reducer according to an embodiment of the present invention; Figure 5 is a cross-sectional view of a cross-roller bearing according to an embodiment of the present invention; Figure 6 is a schematic diagram of a wave generator and a flexible wheel explosion according to an embodiment of the present invention; Figure 7 is an exploded schematic diagram of a torque limiter according to an embodiment of the present invention; Figure 8 4 is a cross-sectional view of a torque limiter according to an embodiment of the present invention.

[0017] In the figure: 1, wave generator; 101, camshaft; 102, flexible wheel bearing; 2, rigid wheel; 3, torque limiter; 301, inner hole shaft; 3011, first meshing ball position; 302, flexible wheel connecting ring; 3021, second meshing ball position; 303, ball; 304, ring release; 4, flexible wheel; 5, adapter plate; 6, connecting shaft; 7, cross roller bearing; 701, bearing inner ring; 702, bearing first outer ring; 703, bearing second outer ring; 704, cross roller; 705, sealing ring. DETAILED DESCRIPTION

[0018] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0019] like Figures 1 to 8 As shown, a harmonic reducer with torque limitation includes a wave generator 1 and a torque limiter 3, the wave generator 1 is connected to a flexible wheel 4, and the flexible wheel 4 is meshed with a rigid wheel 2; the torque limiter 3 is composed of an inner hole shaft 301 and a flexible wheel connecting ring 302, and the two are dynamically coupled through a ball 303 and a meshing ball position; the flexible wheel 4 is connected to the flexible wheel connecting ring 302, and the inner hole shaft 301 is connected to the connecting shaft 6; the inner hole shaft 301 is movably connected to the flexible wheel connecting ring 302; When the impact torque exceeds the preset upper limit, the ball 303 disengages from the inner hole shaft 301, thereby realizing mechanical decoupling of the flexible wheel 4 and the connecting shaft 6. Therefore, the flexible wheel 4 will not be reversely braked by the connecting shaft 6, thereby avoiding mechanical damage such as permanent deformation of the tooth shape of the flexible wheel 4 and jamming of the flexible wheel bearing 102 of the wave generator 1 caused by mechanical impact, and also avoiding overload and burning of the winding of the drive motor connected to the flexible wheel 4. The accumulation of impact loads can also be avoided by instantaneous disengagement of the connecting parts, thereby providing overload protection for the mechanical equipment.

[0020] A first meshing ball position 3011 is radially extended from the outer circumference of the inner hole shaft 301, and a second meshing ball position 3021 is provided at the bottom surface of the flexible wheel connecting ring 302. The first meshing ball position 3011 and the second meshing ball position 3021 form an angle, and the ball 303 is clamped in the angle formed by the first meshing ball position 3011 and the second meshing ball position 3021. A stripping ring 304 is provided on the side of the ball 303 facing away from the first meshing ball position 3011 and the second meshing ball position 3021. The inner circumferential surface of the stripping ring 304 generates a radial constraint force through elastic deformation, so that the ball 303 remains in engagement with the first meshing ball position 3011 and the second meshing ball position 3021. The two-way contact cooperation of the meshing ball position 3021; ​​the line connecting the annular contact surface of the stripping ring 304 and the center of the ball 303 and the pressure angle formed by the first meshing ball position 3011 and the second meshing ball position 3021 are in a complementary geometric relationship. When a mechanical impact occurs, the stripping ring 304 disengages in the direction away from the angle, so that the ball 303 is no longer stuck in the angle. After the ball 303 is disengaged, there is no intermediate medium connecting the first meshing ball position 3011 and the second meshing ball position 3021, so that the movements of the inner hole shaft 301 and the flexible wheel connecting ring 302 do not interfere with each other, so the linkage between the two can be disengaged.

[0021] The wave generator 1 includes a camshaft 101 and a flexible wheel bearing 102. The wave generator 1 serves as a power input component. Through the cooperation of the elliptical cam and the flexible bearing 102, the wave generator 1 forces the flexible wheel 4 to undergo periodic elastic deformation, thereby achieving dynamic adjustment of the tooth surface contact area. During operation, the rotation of the wave generator 1 drives the flexible wheel 4 to produce radial deformation, so that the flexible wheel teeth and the rigid wheel teeth are meshed in the major axis area of ​​the ellipse and are out of contact in the minor axis area, thereby achieving speed change of the connecting components at both ends of the reducer.

[0022] The connecting shaft 6 is connected to the cross roller bearing 7, the cross roller bearing 7 is connected to the adapter plate 5, the adapter plate 5 is connected to the rigid wheel 2, the cross roller bearing 7 includes a bearing inner ring 701, a bearing outer ring and a cross roller 704, lubricating grease is provided between the bearing inner ring 701 and the bearing outer ring, and a sealing ring 705 is provided between the second bearing outer ring 703 and the bearing inner ring 701. In this embodiment, the sealing ring 705 is a fluororubber sealing ring, and the cross section of the sealing ring 705 is a lip-shaped structure to achieve two-way dustproof and grease barrier.

[0023] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A harmonic reducer with torque limitation, characterized in that: It comprises a wave generator (1) and a torque limiter (3), the wave generator (1) is connected to a flexible wheel (4), and the flexible wheel (4) is meshed with a rigid wheel (2); The torque limiter (3) is composed of an inner hole shaft (301) and a flexible wheel connecting ring (302), and the two are dynamically coupled through a ball (303) and a meshing ball position; The flexible wheel (4) is connected to the flexible wheel connecting ring (302), and the inner hole shaft (301) is connected to the connecting shaft (6); the inner hole shaft (301) and the flexible wheel connecting ring (302) are movably connected; When the torque exceeds a preset upper limit, the ball (303) is disengaged from the inner hole shaft (301), thereby achieving mechanical decoupling of the flexible wheel (4) and the connecting shaft (6).

2. The harmonic reducer with torque limitation according to claim 1, characterized in that: A first meshing ball position (3011) is radially extended from the outer periphery of the inner hole shaft (301), a second meshing ball position (3021) is provided at the bottom surface of the flexible wheel connecting ring (302), the first meshing ball position (3011) and the second meshing ball position (3021) form an angle, and the ball (303) is clamped in the angle formed by the first meshing ball position (3011) and the second meshing ball position (3021).

3. The harmonic reducer with torque limitation according to claim 2, characterized in that: A stripping ring (304) is provided on the side of the ball (303) facing away from the first meshing ball position (3011) and the second meshing ball position (3021); the inner circumferential surface of the stripping ring (304) generates a radial restraining force through elastic deformation, so that the ball (303) maintains a two-way contact fit with the first meshing ball position (3011) and the second meshing ball position (3021); and the line connecting the annular contact surface of the stripping ring (304) and the center of the ball (303) and the pressure angle formed by the first meshing ball position (3011) and the second meshing ball position (3021) are in a complementary geometric relationship.

4. The harmonic reducer with torque limitation according to claim 1, characterized in that: The wave generator (1) comprises a camshaft (101) and a flexspline bearing (102).

5. The harmonic reducer with torque limitation according to any one of claims 1 to 4, characterized in that: The connecting shaft (6) is connected to the cross roller bearing (7), the cross roller bearing (7) is connected to the adapter plate (5), and the adapter plate (5) is connected to the rigid wheel (2).

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