Dual-ratio harmonic drive module

Abstract

The application discloses a double-speed-ratio harmonic drive module, which comprises a planet carrier, a cam structure at the outer edge of the planet carrier, and a planet wheel arranged on the end face of the planet carrier; a sun gear is arranged between the planet wheels in the axial direction of the planet carrier, and the end of the sun gear away from the hollow cylinder forms a harmonic fixed seat; the end of the harmonic fixed seat is connected with a driving motor towards the output end; the end of the harmonic fixed seat is connected with the outer ring of a cross roller bearing provided with a steel wheel tooth profile surface, and the inner ring of the cross roller bearing radially receives a flexible gear wheel which acts on the steel wheel tooth profile surface; a brake disc is fixed on the end face of the planet carrier; a gear ring is arranged in the hollow space and meshes with the outer teeth of each planet wheel, and a brake seat fixed with an output flange is rotatably supported in the radial direction of the gear ring, and a brake switching device is further arranged in the inner hole of the brake seat, so that the sun gear output is selectively separated or combined with the brake seat through the planet wheel. The double-speed-ratio harmonic drive module can meet the free switching of speed ratio and torque under different use conditions, and can save the motor installation space.

Description

Technical Field

[0001] This application relates to the field of harmonic drive technology, and more specifically, to a new wave generator, a wave generator assembly with planetary gears that can switch speeds, and a dual-speed ratio harmonic drive module composed thereof. Background Technology

[0002] The development of robot joint modules places increasingly higher demands on their size design, pursuing lightweight, small size, and better transmission performance. Harmonic drive devices have advantages such as large single-stage transmission ratio, small size, small weight, and high motion precision. They can also operate normally in confined spaces and under conditions of media radiation, making them more suitable for applications of light-load precision deceleration, such as humanoid robots.

[0003] Conventional harmonic drive mechanisms can only output one speed. When robot joint modules need to switch freely between different usage conditions, conventional harmonic drive mechanisms cannot meet the current requirements.

[0004] Meanwhile, in the traditional design of rotary direct-drive motors in harmonic drives, off-the-shelf packaged motors are typically chosen, where the stator and rotor are encapsulated within a motor housing using bearings and flanges. This allows for simple installation of the entire motor onto the mechanical equipment and connection to the load. However, in many practical applications, installation space is severely limited. For example, the arm of a collaborative robot often integrates six, seven, or even more motor modules to drive the robot's joints.

[0005] Traditional motor packaging methods cannot meet application requirements due to insufficient installation space. Even when used in more precise harmonic speed reduction mechanisms, they cannot meet the comprehensive needs of diverse space and speed switching. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a dual-speed ratio harmonic drive module that can meet the different switching requirements of robot joint modules for output speed, while saving installation space and improving overall utilization.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A dual-speed ratio harmonic drive module, characterized in that it includes: The planetary carrier is a stepped hollow cylinder with a cam structure on one side of the cylinder and multiple planetary gears on the annular end face of the other end. The sun gear is a hollow cylindrical body and is positioned between the planet gears along the axial direction of the planet carrier. The hollow cylindrical body of the sun gear has teeth that mesh with the external teeth of the planet gears. The end of the sun gear away from the hollow cylindrical body forms a harmonic fixing seat. The harmonic mounting base is connected at its end to a cross roller bearing outer ring with a steel wheel tooth profile on its inner wall. The cross roller bearing inner ring radially supports a flexible wheel that interacts with the steel wheel tooth profile. The flexible wheel is supported by a flexible bearing on the outer edge of the cam structure. The inner wall of the cam structure is rotatably supported on the outer shoulder of the harmonic mounting base. The brake disc is fixed to the end face of the planetary carrier. An output flange is provided at the end of the cross roller bearing inner ring. A hollow space is formed between the output flange, the flexible wheel, and the brake disc. A gear ring is set in the hollow space, with radial internal teeth meshing with the external teeth of each planet gear. A brake seat is fixed to the output flange and is radially rotatably supported on the gear ring. A brake switching device is also set in the inner hole of the brake seat, so that the output of the sun gear can be selectively separated or engaged with the planet gears and the brake seat. The end of the harmonic mounting bracket faces the output end and is connected to the drive motor to form a dual-speed ratio drive module.

[0008] In the above technical solution, a first deep groove ball bearing is provided between the outer edge of the brake seat and the gear ring to form a rotatable support structure; a second deep groove ball bearing is provided between the inner wall of the cam and the outer side of the shoulder of the harmonic fixing seat to form a rotatable support structure.

[0009] In the above technical solution, the brake switching device is an electromagnet adsorption structure, wherein a ring-shaped shift paddle and a wave spring are arranged inside the gear ring; an outer gear ring is arranged on the radial outer periphery of the shift paddle, the teeth of which are always engaged with the inner gear ring of the brake seat, and the inner gear ring of the shift paddle selectively engages with the circumferential outer teeth of the brake disc; the electromagnet is fixed in the inner hole of the brake seat and placed inside the gear ring, and is configured such that when it is not energized, the wave spring is open to keep the shift paddle engaged with the brake disc, and when it is energized, the wave spring is attracted to keep the shift paddle separated from the brake disc.

[0010] In the above technical solution, when the electromagnet is not energized, the output is a low speed ratio and high torque; when the electromagnet is energized, the shift paddles are separated from the brake disc, and the output is a high speed ratio and low torque. In the above technical solution, 3-5 planetary gears are spaced apart.

[0011] In the above technical solution, the end face of the flexible bearing is flush with the end face of the planetary carrier cam structure, and they both contact the end face of the harmonic fixing seat.

[0012] In the above technical solution, a first bearing pressure plate is provided, which is fixed on the flexible wheel and presses against the inner bearing ring of the first deep groove ball bearing.

[0013] In the above technical solution, the inner ring of the flexible bearing is flush with the plane of the outer cam structure of the planetary carrier, and the second bearing pressure plate is fixed to the planetary carrier and presses the inner ring of the flexible bearing.

[0014] In the above technical solution, an expansion sleeve is installed at the center of the output flange.

[0015] In the above technical solution, a frameless motor is fixedly connected to the end of the harmonic mounting bracket; a protective shell is provided between the end cover and the end of the harmonic mounting bracket, the stator and the back cover are fixed on the protective shell, and a circuit board is provided in the gap between the back cover and the protective shell; the rotor is fixed to the rotor seat and rotatably mounted in the stator; the conduit passes through the end of the output flange and is provided along the entire module, and the power line connecting the brake switching device passes through the conduit and is connected to the corresponding chip on the circuit board.

[0016] In the above technical solution, the power line connecting the electromagnet passes through a conduit and connects to the corresponding chip on the circuit board.

[0017] In the above technical solution, the first magnetic ring is fixed on the first magnetic ring seat, the second magnetic ring is fixed on the second magnetic ring seat, the second magnetic ring seat is fixed at the outer diameter of the conduit and the axial height of the second magnetic ring is adjusted to be consistent with the height of the first magnetic ring.

[0018] The joints between the motor housing and the crossed roller bearings are finished with flush-cut drilling and tapping to ensure sufficient connection strength and a certain degree of sealing when the screws are tightened. When the electromagnet is energized, the wave spring is compressed, the shift paddle separates from the brake disc, and the differential motion of the planetary gears is not transmitted to the output flange. The sun gear output only drives the rotation of the cam on the planetary carrier. The waveform change of the wave generator is finally output to the output flange through the flex wheel and the steel wheel; at this time, the output mode is high speed ratio and low torque. When the electromagnet is de-energized, the wave spring forces the shift paddle to engage with the brake disc. The sun gear output drives the differential motion of the planetary gears and the rotation of the cam on the planetary carrier, which together achieve waveform change, and is finally output to the output flange through the flex wheel and the steel wheel, achieving low speed ratio and high torque output.

[0019] Compared to existing technologies, the beneficial effects of this application are: Due to the switching action of the electromagnet, the differential action of the planetary gears is selectively involved in the harmonic drive process. As a result, the power output from the sun gear can be output to the output flange through the differential action of the planetary gears on the planetary carrier, or the power output from the sun gear can be directly applied to the output flange through the waveform change of the cam on the planetary carrier, via the flex wheel and the steel wheel. Ultimately, the output flange can achieve low-speed ratio, high-torque output and high-speed ratio, low-torque output as required, satisfying the need for different speed ratio switching of the same harmonic structure.

[0020] Secondly, the harmonic mounting base is directly formed on the outside of the wave generator through the sun gear. The harmonic mounting base is directly connected to the frameless motor composed of independent rotor and stator components. The stator and rotor are directly fixed to the harmonic structure of the wave generator with planetary gears, thereby simplifying the structure of motor packaging, motor housing and bearing transmission. Electromagnetic protection is cleverly achieved with the help of the equipment shell, while reducing the overall installation space of the dual-speed ratio module, which is suitable for the precision and compact requirements of robot joint modules. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a dual-speed ratio harmonic drive module with planetary gears according to an embodiment of this application.

[0023] Figure 2 for Figure 1 AA sectional view.

[0024] Figure 3 for Figure 2 Diagram showing the positional relationship between the sun wheel and planetary wheels.

[0025] Figure 4 This is a schematic diagram of the planetary carrier transmission structure with a cam structure of the present invention.

[0026] Figure 5 for Figure 4 Side view.

[0027] Figure 6 This is a dynamic schematic diagram of the switching state of the brake switching device of the present invention.

[0028] Figure 7 This is a perspective view of the shift paddles of the present invention.

[0029] Figure 8 for Figure 2 The split diagram.

[0030] Figure 9 This is one embodiment of the present invention, which incorporates a frameless motor to form a dual-speed ratio harmonic drive module.

[0031] The corresponding reference numerals in the attached figures are as follows: 1. Expansion sleeve; 2. Electromagnet; 3. First bearing pressure plate; 4. Flexible wheel; 5. Brake seat; 6. Cross roller bearing; 7. Shift paddle; 8. Second planetary gear; 9. First locating pin; 10. Flexible bearing; 11. Second bearing pressure plate; 12. Second deep groove ball bearing; 13. Motor housing; 14. First magnetic ring; 15. Rear cover; 16. Second magnetic ring; 17. Second magnetic ring seat; 18. Circuit board; 19. First magnetic ring seat; 20. Fourth deep groove ball bearing; 21. Motor stator; 22. Rotor seat; 23. Motor rotor; 24. Third deep groove ball bearing; 24. Third bearing pressure plate; 241. Planetary carrier; 25. Sun gear; 26. First planetary gear; 27. Gear ring; 28. Brake disc; 29. ​​Wave spring; 30. First deep groove ball bearing; 31. Output flange; 32. Cable guide tube; 33. Harmonic fixing seat; 34. Third planetary gear; 35. Second locating pin; 36. Elastic retaining ring or earless snap ring; 37. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0035] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0036] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0037] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0038] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0039] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0040] Example 1 like Figure 1-9 This is a dual-speed ratio harmonic drive module consisting of a wave generator with planetary gears according to the present invention. The second planetary gear 8 is positioned onto the planet carrier 25 by the first locating pin 9. The other two planetary gears, the first planetary gear 27 and the third planetary gear 35, are fixed to the planet carrier 25 by the second locating pin 36 using the same operation. The brake disc 29 is pressed firmly onto the planetary gears with screws to prevent axial movement. The third deep groove ball bearing 24 is pressed into the inner hole of the planet carrier 25, and the flexible bearing 10 is pressed into the cam structure on the outer circle of the planet carrier 25. The inner steel ring of the flexible bearing 10 is flush with the outer plane of the planet carrier 25. The second bearing pressure plate 11 is fixed to the axial end face of the planet carrier 25 with screws to prevent axial movement of the flexible bearing 10. This structure forms a wave generator with planetary gears, replacing the conventional cam structure of harmonic gears. When the planetary gears act, the force is transmitted to the external flexible gear 4 through the flexible bearing 10.

[0041] like Figure 3The diagram shows the meshing of the planetary gears and the sun gear. The sun gear 26 passes through the installed planetary carrier 25, and the teeth of each planet gear mesh with the teeth of the sun gear 26. The third bearing plate 241 presses the sun gear in place, and the third deep groove ball bearing 24 is fixed to the locking harmonic mounting base 34 with screws. The wave spring 30 and the shift paddle 7 are sequentially pressed into the gear ring 28. The sun gear 26 drives the planetary gears to rotate. The hollow shaft end of the sun gear 26 forms the harmonic mounting base 34.

[0042] The first deep groove ball bearing 31 is pressed and fixed to the gear ring 28 by an elastic retaining ring or a circlip 37. The brake seat 5 passes through the first deep groove ball bearing 31 and presses the first deep groove ball bearing 31 against the outer edge of the step of the brake seat 5. The first bearing pressure plate 3 axially presses the inner bearing ring of the first deep groove ball bearing 31 and is fixed to the flexible wheel 4 by screws. The bearing pressure plate 300 located axially between the first deep groove ball bearing 31 and the outermost step of the brake seat 5 presses the outer bearing ring of the first deep groove ball bearing 31. The electromagnet 2 is fixed to the inner hole of the brake seat 5 by screws. The output flange 32 is fixed to the outer ring of the crossed roller bearing 6 by screws. The installed brake seat assembly passes through the inner hole of the output flange 32 and is fixed to the output flange 32 by screws.

[0043] The installed planetary carrier passes through the sun gear 26, and the teeth of each planet gear mesh with the teeth of the sun gear 26; the third deep groove ball bearing 24 is pressed by the third bearing pressure plate and locked onto the harmonic fixing seat 34 by screws; the wave spring 30 and the shift paddle 7 are pressed into the gear ring 28 in sequence.

[0044] The paddle shifter 7 has an outer gear ring 702 on its radial outer circumference. The teeth of this outer gear ring are always engaged with the inner gear ring of the brake seat 5. The inner gear ring 701 of the paddle shifter 7 (with a shorter tooth height along the radial direction from the outer edge inward and protruding from the axial end face) is used to switch gears. When the inner gear ring of the paddle shifter 7 is engaged with the circumferential outer teeth of the brake disc 29, it is in a low gear ratio state and the planetary gears have output; when it is not engaged with the brake disc 29, it is in a high gear ratio state and only the cam outputs.

[0045] The outer ring of the crossed roller bearing 6 remains stationary, while the inner ring of the crossed roller bearing 6 drives the output flange 32 to rotate.

[0046] The bottom cover of the flexible wheel 4 is concentrically set with the output flange 32 and is fixed by annular screws outside the wire hole.

[0047] The internal teeth of gear ring 28 mesh with the external teeth of each planet gear in the planetary gear set.

[0048] When the electromagnet is energized, the wave spring is compressed, the shift paddles separate from the brake disc, and the differential motion of the planetary gears is not transmitted to the output flange. The sun gear output only drives the waveform change of the cam on the planet carrier, which is finally output to the output flange through the flexspline and steel wheel. The output mode is high speed ratio and low torque. The high speed ratio range can be from 200 to 500. The optimal torque is about 40 Nm when the high speed ratio is selected.

[0049] When the electromagnet is de-energized, the wave spring forces the shift paddles to engage with the brake disc. The output of the sun gear drives the differential motion of the planetary gears, and the wave motion of the cam on the planet carrier works together to ultimately output to the output flange through the flexspline and steel wheel, achieving a low-speed ratio, high-torque output. The low-speed ratio can range from 30 to 120. The optimal torque at the preferred low-speed ratio is approximately 190 Nm.

[0050] It can freely switch the speed ratio and torque under different usage conditions, and can save motor installation space when forming modules later.

[0051] The dual-speed ratio harmonic drive module includes a tensioning sleeve 1, an electromagnet 2, a first bearing pressure plate 3, a flexible wheel 4, a brake seat 5, a crossed roller bearing 6, a shift paddle 7, a second planetary gear 8, a first positioning pin 9, a flexible bearing 10, a second bearing pressure plate 11, a second deep groove ball bearing 12, a motor housing 13, a first magnetic ring 14, a rear cover 15, a second magnetic ring 16, a second magnetic ring seat 17, a circuit board 18, a first magnetic ring seat 19, a fourth deep groove ball bearing 20, a motor stator 21, a rotor seat 22, a motor rotor 23, a third deep groove ball bearing 24, a third bearing pressure plate 241, a planetary carrier 25, a sun gear 26, a first planetary gear 27, a gear ring 28, a brake disc 29, a wave spring 30, a first deep groove ball bearing 31, an output flange 32, a cable guide 33, a harmonic fixing seat 34, a third planetary gear 35, and a second positioning pin 36.

[0052] The first deep groove ball bearing 31 is pressed and fixed to the gear ring 28 by an elastic retaining ring or a circlip 37. The brake seat 5 passes through the first deep groove ball bearing 31 and presses the first deep groove ball bearing 31 against the step of the brake seat 5. The first bearing pressure plate 3 presses the inner bearing ring of the first deep groove ball bearing 31 and is fixed to the flexible wheel 4 by screws. The bearing pressure plate 300 presses the outer bearing ring of the first deep groove ball bearing 31. The electromagnet 2 is fixed to the inner hole of the brake seat 5 by screws. The output flange 32 is fixed to the outer ring of the crossed roller bearing 6 by screws. The installed brake seat assembly passes through the inner hole of the output flange 32 and is fixed to the output flange 32 by screws.

[0053] The motor rotor 23 is pressed against the outer diameter of the rotor seat 22 and fixed with structural adhesive. The second deep groove ball bearing 12 is fixed at the step of the rotor seat 22. The sun gear 26 is fixed on the rotor seat 22 with screws. The fourth deep groove ball bearing 20 is pressed against the inner hole of the motor housing 13. The motor stator 21 is pressed against the inside of the motor housing 13 and fixed with structural adhesive. The installed motor rotor assembly is pressed against the installed motor housing. The motor housing 13 is fixed to the harmonic mounting base 34 with screws.

[0054] The motor stator 21 is fixed to the motor housing 13, and the rotor 23 is fixed to the rotor base 22.

[0055] The installed planetary carrier passes through the sun gear 26, and the teeth of each planetary gear mesh with the teeth of the sun gear 26. The third deep groove ball bearing 24 is pressed by the third bearing pressure plate 241 and locked onto the harmonic fixing seat 34 by screws. The wave spring 30 and the shift paddle 7 are pressed into the gear ring 28 in sequence. The installed motor assembly is fixed to the crossed roller bearing 6 by screws. The first magnetic ring seat 19 is locked to the rotor seat 22 by screws. When the motor is started, the harmonic rotation is smooth and without abnormal noise.

[0056] The conduit 33 passes through the expansion sleeve 1 and is flush with the end face of the expansion sleeve 1. The conduit 33 is fixed with screws. The first magnetic ring 14 is bonded to the first magnetic ring seat 19 with structural adhesive. The second magnetic ring 16 is bonded to the second magnetic ring seat 17 with structural adhesive. The second magnetic ring seat 17 is fixed to the outer diameter of the conduit 33 with set screws, and the height of the second magnetic ring 16 is adjusted to match the height of the first magnetic ring 14. The circuit board 18 is fixed to the motor housing 13 with screws. The power cable of the electromagnet 2 is passed through the inner hole of the conduit 33 and connected to the corresponding chip on the circuit board 18. The back cover 15 is fixed to the motor housing 13 with screws.

[0057] Of course, the motor in this embodiment can also be a conventional motor, which can be directly selected and used. This is not intended to limit the invention.

[0058] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A dual-speed ratio harmonic drive module, characterized in that, include: The planetary carrier is a stepped hollow cylinder with a cam structure on one side of the cylinder and multiple planetary gears on the annular end face of the other end. The sun gear is axially positioned between the planet gears along the planet carrier. The hollow cylinder of the sun gear has teeth that mesh with the external teeth of the planet gears. The end of the sun gear away from the hollow cylinder forms a harmonic mounting base. The end of the harmonic mounting base facing the output end is connected to the drive motor. The harmonic mounting base is connected at its end to a cross roller bearing outer ring with a steel wheel tooth profile on its inner wall. The cross roller bearing inner ring radially supports a flexible wheel that interacts with the steel wheel tooth profile. The flexible wheel is supported by a flexible bearing on the outer edge of the cam structure. The inner wall of the cam structure is rotatably supported on the outer shoulder of the harmonic mounting base. The brake disc is fixed to the end face of the planetary carrier. An output flange is provided at the end of the cross roller bearing inner ring. A hollow space is formed between the output flange, the flexible wheel, and the brake disc. A gear ring is set in the hollow space, with radial internal teeth meshing with the external teeth of each planet gear. A brake seat is fixed to the output flange and is radially rotatably supported on the gear ring. A brake switching device is also set in the inner hole of the brake seat, so that the output of the sun gear can be selectively separated or engaged with the planet gears and the brake seat. The brake switching device is an electromagnet adsorption structure, wherein a ring-shaped shift paddle and a wave spring are arranged inside the gear ring; an outer gear ring is arranged on the radial outer periphery of the shift paddle, the teeth of which are always engaged with the inner gear ring of the brake seat, and the inner gear ring of the shift paddle selectively engages with the circumferential outer teeth of the brake disc; the electromagnet is fixed in the inner hole of the brake seat and placed inside the gear ring, and is configured such that when it is not energized, the wave spring is open to keep the shift paddle engaged with the brake disc, and when it is energized, the wave spring is attracted to keep the shift paddle separated from the brake disc.

2. The dual-speed ratio harmonic drive module according to claim 1, characterized in that, A first deep groove ball bearing is provided between the outer edge of the brake seat and the gear ring to form a rotatable support structure; a second deep groove ball bearing is provided between the inner wall of the cam and the outer side of the shoulder of the harmonic mounting seat to form a rotatable support structure.

3. The dual-speed ratio harmonic drive module according to claim 1, characterized in that, When the electromagnet is not energized, the output is low speed ratio and high torque; when the electromagnet is energized, the shift paddles are separated from the brake disc, and the output is high speed ratio and low torque.

4. The dual-speed ratio harmonic drive module according to claim 1, characterized in that, The flexible bearing is flush with the end face of the planetary carrier cam structure and together they contact the end face of the harmonic mounting base.

5. The dual-speed ratio harmonic drive module according to claim 1, characterized in that, A first bearing pressure plate is set, fixed on the flexible wheel, and presses against the inner bearing ring of the first deep groove ball bearing.

6. The dual-speed ratio harmonic drive module according to claim 1, characterized in that, The inner ring of the flexible bearing is flush with the outer cam structure plane of the planetary carrier, and the second bearing pressure plate is fixed to the planetary carrier and presses the inner ring of the flexible bearing.

7. The dual-speed ratio harmonic drive module according to claim 1, characterized in that, The frameless motor is fixedly connected to the end of the harmonic mounting bracket.

8. The dual-speed ratio harmonic drive module according to claim 1, characterized in that, A protective shell is provided between the end cover and the end of the harmonic fixing seat. The stator and the rear cover are fixed on the protective shell. A circuit board is provided in the gap between the rear cover and the protective shell. The rotor is fixed to the rotor seat and rotatably installed in the stator. The conduit passes through the end of the output flange and is provided along the entire module. The power line connecting the brake switching device passes through the conduit and is connected to the corresponding chip on the circuit board.

9. The dual-speed ratio harmonic drive module according to claim 1, characterized in that, The power cord connecting the electromagnet passes through a conduit and connects to the corresponding chip on the circuit board.

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