Parallel-type high-efficiency composite flexible cylinder-type harmonic reducer having built-in outer rotor motor

Abstract

A parallel-type high-efficiency composite flexible cylinder-type harmonic reducer having a built-in outer rotor motor. The harmonic reducer comprises a moving part, a static part, and a variable-stiffness connecting part (11a). A flexible tube (11), inner surfaces of two ends of which being integrated with flexible bearing outer raceways, outer surfaces being provided with gear teeth, and a middle part having an equal diameter, and a wave generator (8) having the same structural dimensions as the two ends integrated in the motor outer rotor, and perpendicular to a long axis thereof, provided with a flexible bearing inner raceway on an outer surface thereof, are assembled into the moving part by means of two identical ball or spherical roller cage assemblies (10). A motor inner stator (6) being fixedly connected to covering rigid wheels (1) at the two ends forms the static part. By using orthogonal anti-symmetric deformation of the flexible cylinder, half of an input torque of the motor is amplified in the same proportion by two harmonic drive assemblies having the same modulus and the same difference in tooth number, and is output by the variable-stiffness connecting part of the outer circle, after cross sections in the constant circle flexible cylinder are overlapped, and the two harmonic drive assemblies are connected in parallel to reduce speed in the same proportion. Since there is no circularity constraint in the cross section of the flexible cylinder, a wall thickness of an elastic part is reduced by the flexible cylinder composite flexible bearing outer ring; thus transmission efficiency is high.

Description

Parallel high-efficiency composite flexible-cylinder harmonic reducer with built-in outer rotor motor Technical Field

[0001] The present invention belongs to the field of mechanical transmission technology, and particularly relates to a parallel-type high-efficiency composite flexible-cylinder harmonic reducer with a built-in outer rotor motor. The invention proposes the idea of ​​two harmonic transmission components working in parallel, and makes the active harmonic reducer compact in structure, small in size and high in transmission efficiency by integrating some static and dynamic components, reducing non-working materials of flexible components to reduce their deformation energy consumption, and building and integrating the driving source - the outer rotor motor - into the reducer. Background Art

[0002] Harmonic reducers, characterized by their compact size, high transmission ratio, light weight, and high transmission accuracy, are core transmission components for automated control devices such as robots, mechanical equipment, and medical equipment. As more and more equipment moves toward automation and intelligence, the performance requirements for harmonic reducers are increasing. Unlike conventional transmissions, the core principle of a harmonic reducer is to utilize the elastic deformation of a flexible component during operation to generate harmonic motion to transmit motion and power. It primarily consists of a wave generator, a flexible bearing, a flexspline with teeth on the end, and a rigid wheel with internal teeth of the same module. The wave generator is a non-circular cam. The flexible bearing is mounted on the wave generator and embedded in the inner bore of the flexspline. When the wave generator is in operation, it causes the flexspline to undergo controlled elastic deformation, causing the teeth on both ends of the deformed long shaft of the flexspline to mesh simultaneously with the inner teeth of the rigid wheel. Due to the small tooth difference between the rigid and flexsplines, the teeth on the deformed short shaft of the flexspline completely disengage from the inner teeth of the rigid wheel, forcing the flexspline to generate harmonic deformation motion to transmit motion and torque, achieving a high reduction ratio.

[0003] The outer ring of the flexible bearing and the flexspline are the two core elastic components of the harmonic reducer, yet they are manufactured as separate parts. Both retain elastic wall thickness material required for independent part processing but not required during operation. However, this material will also elastically deform during reducer operation, consuming energy. The inner ring of the flexible bearing is manufactured as a circular shape before the wave generator is installed. However, after installation, the inner ring becomes non-circular, matching the wave generator and subject to assembly bending stress. The non-circular wave generator also changes the curvature of the outer raceway grooves in each radial section, affecting the high-speed operation and force of the bearing rolling elements. The assembly of these discrete parts inevitably increases the number of interfaces in the force or torque transmission path, complicating the constraints between the components and reducing the structural strength of each component.

[0004] Existing flexible-wheel harmonic reducers have only a single harmonic transmission component, that is, one end of the flexible wheel generates harmonic deceleration motion and amplifies torque, while the torque output at the other end of the flexible wheel must rely on its diaphragm structure such as the cup bottom or hollow flange, or the circular constraint of the meshing rigid wheel with the same number of teeth. These constraint structures consume elastic deformation energy to generate or limit the deformation of the flexible wheel during operation. This is one of the main reasons for the low transmission efficiency of existing flexible-wheel harmonic reducers. In essence, it sacrifices transmission efficiency to achieve a large reduction ratio with a small reducer.

[0005] In the existing flexible-wheel harmonic reducer, each point on the circumference of the open end of the flexible wheel swings outward and inward with the cup bottom cross-section point on the respective flexible wheel generatrix as the center of the circle during rotation, and the swing value is the largest. That is, the swing value of each point on the axial direction of the end spur gear is not equal, but the teeth on the rigid and flexible wheels are all processed as spur gears parallel to the axis, resulting in additional elastic constraints when the rigid and flexible wheels mesh at the long shaft end, and increasing the sliding friction and wear of the meshing tooth surfaces. Summary of the Invention

[0006] To address the aforementioned shortcomings of the prior art, the present invention provides a parallel, high-efficiency, composite flexible-cylinder harmonic reducer with an internal external rotor motor. Its core principle is to utilize the orthogonal, antisymmetric deformation of a thin-walled flexible cylinder with a constant diameter in the middle due to coaxially mounted wave generators of the same structural dimensions and perpendicular long axes at both ends (the core principle of invention patent application publication number CN 117330313 A). Two harmonic drive assemblies at either end of the flexible cylinder, each with the same module and tooth number difference, amplify half of the torque from the same input source in equal proportion. The amplified, identically oriented torques at both ends are superimposed on the central cross-section of the constant-circle flexible cylinder and output by a variable-stiffness coupling on its outer circumference. The two harmonic drive assemblies effectively perform the same reduction in speed in parallel.

[0007] The reducer is compactly assembled, diametrically and axially, with an integrated moving component, an integrated stationary component, and an elastic coupling output element with low axial stiffness and high circumferential stiffness. The integrated moving component comprises a flexible cylinder with flexible bearing outer ring raceways integrated on both ends, a gear on the outer surface, and a uniformly thin-walled central structure. Two wave generators of the same structural dimensions, with perpendicular long axes and flexible bearing inner ring raceways integrated on the outer surfaces, are integrated at both ends of the motor's outer rotor. These wave generators are assembled via two identical ball or spherical roller cage assemblies. In the unassembled, free state, the central cross-section of the flexible cylinder, along its axis, is a uniformly circular ring.

[0008] The integrated stationary component consists of the motor's internal stator and two end cap-shaped rigid wheels fixedly connected to the ends of the stator shaft. The two sets of rigid wheel internal gears have the same module and tooth count difference as the flexible cylinder external gear. They can mesh harmonically with the flexible cylinder's maximum expansion angle parallel to the cylinder's, or with internal bevel gears, with the inclined end faces. Because each point on the flexible cylinder's end circumference oscillates with the maximum oscillation value around the midsection of the flexible cylinder's generatrix, the axial oscillation values ​​of each point on the end gear teeth parallel to the axis vary. Therefore, the long generatrix of the rigid wheel teeth in parallel-axis harmonic meshing should be parallel to the maximum expansion angle of the flexible cylinder. By chamfering the tooth ends, the disengagement clearance is set to 2 / 5 or less of the difference between the long and short axis lengths of the wave generator, and the gear meshing height is set to 3 / 5 or more of this half-length difference. Similarly, in order to make full use of the composite elastic material and the external angle of the flexible cylinder end, the oblique end faces are harmonically meshed, and the rigid wheel uses an internal bevel gear to mesh with the flexible cylinder conical gear.

[0009] Taking advantage of the characteristic that the flexible cylinder's mid-section remains circular during operation, with only slightly varying deflections, torque is output on the outer side of the flexible cylinder wall at this section using a bridge-shaped ridge connection or toothed meshing pair with low axial stiffness near the wall and high circumferential stiffness at the far wall. This reduces the constraints imposed by the output coupling on the slightly varying deflections at various points around the circumference of the flexible cylinder's mid-section. A pair of angular contact ball bearings on the rotating housing of the variable-stiffness coupling withstand the radial and axial forces external to the torque output end.

[0010] The outer rotor of the motor built into the flexible cylinder is supported by the meshing of the gear teeth at both ends of the long axis of the flexible cylinder or suspended in the teeth of two rigid wheels with the help of two ball or spherical roller cage assemblies with the same deformation, and is coaxial with the two rigid wheels due to the two wave generators with the same structural dimensions and perpendicular long axes in the integrated moving parts. The axial displacement of the ball or spherical roller cage assembly is constrained by the mutually perpendicular outward and inward deformation of the flexible cylinder ports, as well as the non-parallel axis meshing constraint between the axisymmetric rigid wheels and flexible cylinder teeth. In addition, the rigid rotating shell supported by the angular contact ball bearing can assist in constraining the radial and axial displacement of the outer rotor through the flexible cylinder through the variable stiffness connection outside the cross section of the flexible cylinder. Therefore, there is no need for bearing support between the stator and rotor of the built-in outer rotor motor, and the entire reducer is like a low-speed, high-torque motor with rotating shell.

[0011] Since the cross-section of the flexible cylinder always remains naturally circular during the working process, and the variable stiffness connection output member has little constraint effect on the different micro-deflection deformations at various circumferential points of the cross-section, the energy consumption of the reducer output end during operation is extremely small; also because the two flexible parts, the flexible cylinder and the flexible bearing outer ring, are combined into one, the wall thickness of the elastic part required by the processing technology of the original two separate parts but not required during operation is greatly reduced, so the deformation energy loss of the most core elastic part in the harmonic reducer during operation can also be greatly reduced; the two harmonic drive components working in parallel are reduced by half because the load is reduced by half. Under the conditions of the same flexible component bending stiffness and wall thickness, the wall thickness of the elastic part of the parallel high-efficiency composite flexible cylinder harmonic reducer can be less than half of that of the single harmonic drive component, so the transmission efficiency of the reducer is high and the failure rate of the flexible part is low.

[0012] Even if the dynamic and static parts of the reducer are assembled with separate parts without corresponding integration, the word "composite" can be removed from the name, but the functions and advantages of the flexible cylinder harmonic reducer are still there, except that the radial size is slightly larger, the transmission efficiency is lower, the number of interfaces in the force or torque transmission path is more, and its manufacturing process is relatively more mature and simple.

[0013] The reducer can also be used in reverse to become a speed increaser, which can convert low-speed, high-torque input into high-speed, low-torque output. Therefore, as long as the built-in outer rotor motor is replaced with a built-in outer rotor generator, two wave generators with the same structural size and mutually perpendicular long axes and flexible bearing inner ring raceways on the outer surface are integrated at both ends of the generator outer rotor, a parallel high-efficiency composite flexible cylinder harmonic speed increaser can be realized, thereby increasing the speed of low-speed mechanical energy and generating electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of the structure of a flexible-wheel harmonic reducer and the elastic deformation of the outer ring of a flexible bearing during operation;

[0015] FIG2 is a schematic structural diagram of a preferred embodiment of the present invention - a parallel high-efficiency composite flexible-cylinder harmonic reducer with a built-in outer rotor motor;

[0016] FIG3 is a schematic diagram of a motor outer rotor according to the present invention, in which two wave generators of the same structural size and perpendicular long axes are integrated at both ends and the outer surface of the wave generator has a flexible bearing inner ring raceway;

[0017] FIG4 is a schematic diagram showing a structure comparison of whether the moving component and the static component are integrated or not according to the present invention;

[0018] 5 is a schematic structural diagram of a parallel high-efficiency composite flexible-cylinder harmonic reducer of the present invention, which uses a spherical roller cage assembly and a tapered roller bearing support and an oblique end face harmonic meshing and a variable stiffness tooth meshing pair coupling. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] In the following description, specific details, such as certain internal procedures and techniques, are provided for purposes of illustration and not limitation to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0021] As shown in Figure 1a, the flexspline harmonic reducer consists of a wave generator 102, a flexible bearing 103, a flexspline 101 and a rigid wheel 104, that is, it only contains one set of harmonic transmission components, wherein the flexible bearing 103 is installed on the wave generator 102, becomes a non-circular shape, and is then embedded in the flexspline 101, forcing the flexspline 101 to deform. When the wave generator 102 is running, the flexspline 101 can produce controllable elastic deformation, and the gear teeth on the outer circle at both ends of the long axis of the flexspline 101 are simultaneously engaged with the inner circle gear teeth of the rigid wheel 104. Moreover, due to the tooth difference of several teeth between the gears on the rigid wheel 104 and the flexspline 101, the gear teeth at the short axis of the deformed flexspline 101 are completely disengaged from the inner gear teeth of the rigid wheel 104, forcing the flexspline 101 to produce harmonic deformation motion to transmit motion and torque, thereby achieving the purpose of a large reduction ratio. The deformation diagram of the flexible bearing outer ring 103A is shown in FIG1 b . The outer ring 103A is expanded at the long axis end and contracted at the short axis end. Therefore, this type of harmonic reducer has the three disadvantages described in the background art.

[0022] In view of the above problems, the present invention will describe a parallel high-efficiency composite flexible-cylinder harmonic reducer with a built-in outer rotor motor in combination with embodiments.

[0023] Example 1

[0024] As shown in Figure 2, this embodiment provides a parallel, high-efficiency, composite flexible-cylinder harmonic reducer for an internally mounted outer rotor motor. In this embodiment, the reducer is comprised of an integrated moving component, an integrated static component, and an elastic coupling output member with low axial stiffness and high circumferential stiffness, compactly arranged in the radial and axial directions. The integrated moving component comprises a flexible cylinder 11 with integrated flexible bearing outer ring raceways on both ends, a gear on the outer surface, and a uniform diameter in the middle. This is assembled with two wave generators 8 of the same structural dimensions, with mutually perpendicular long axes, and flexible bearing inner ring raceways on the outer surface, integrated at both ends of the motor's outer rotor, which is embedded with permanent magnets 8A. These wave generators are assembled via two identical ball retainer assemblies 10.

[0025] As shown in Figure 2, the integrated stationary component consists of the motor's internal stator 6 and two end cap-shaped rigid wheels 1 fixedly connected to the ends of the stator shaft 2. The internal gears of the two sets of rigid wheels 1 and the external gears of the flexible cylinder 11 have the same module and tooth count difference. The rigid wheel teeth mesh harmonically with the flexible cylinder teeth, parallel to the maximum external angle of the flexible cylinder 11. As shown in the functional block diagram, these two harmonic drive components are effectively connected in parallel, performing the same proportional reduction. The motor's internal stator 6 and the two rigid wheels 1 are axially fixed to the stator shaft 2 by a retaining ring 5 and a spring collar 4. The power cord 3 passes through the inner bore of the stator shaft 2 to electrically connect to the internal stator 6.

[0026] As shown in Figure 2, a bridge-hole ridge connector 11A, with low axial stiffness near the wall and high circumferential stiffness at the far wall, is fastened to the rotating housing 12 via screws. This variable-stiffness connection reduces the constraint imposed by the output coupling on the varying micro-deflections at various points along the circumference of the flexible cylinder's midsection, effectively reducing energy consumption. The rotating housing 12 is supported by a pair of angular contact ball bearings 9, which are pre-tightened to the rigid wheel 1 by screws on the end cap 7. The rotating housing 12 outputs amplified torque at a low rotational speed while also withstanding external radial and axial forces.

[0027] FIG3 shows a schematic volume view of a motor outer rotor embedded with permanent magnets 8A, with two wave generators 8 of the same structural size and perpendicular long axes integrated at both ends, and with flexible bearing inner ring raceways on the outer surfaces.

[0028] As shown in FIG2 , the characteristic that each point on the circumference of the end of the flexible cylinder 11 oscillates outward and inward with the mid-section point on its respective cylinder generatrix as the center during rotation, with the oscillation value being the largest, is utilized. That is, the axial oscillation values ​​of the spur gear teeth at the end parallel to the axis are not uniform. Therefore, the generatrix of the teeth of the rigid wheel 1 in parallel-axis harmonic meshing should be parallel to the maximum splay angle of the flexible cylinder 11, as shown in the partially enlarged view of FIG4 . In this case, by chamfering the tooth ends, a value of 2 / 5 or less of half the difference between the major and minor axis lengths of the wave generator 8 is used as the disengagement clearance, and 3 / 5 or more of half the length difference is used as the gear meshing height, thereby increasing the meshing area. Furthermore, the meshing between the teeth at both ends of the major axis of the flexible cylinder 11 and the teeth of the rigid wheel 1 is a spur meshing, which optimizes the force distribution. Similarly, in order to make full use of the composite elastic material and the external angle of the flexible tube end, the oblique end face is meshed in a harmonic manner. The internal bevel gear of the rigid wheel 1 shown in Figure 5 can be used for meshing. The gear of the flexible tube 11 is conical. Because part of the rib material of the outer raceway of the flexible bearing is borrowed, the material at the end of the flexible tube 11 is reduced, so as to maximize the meshing area and reduce the deformation energy consumption of the flexible tube 11 at this location.

[0029] Example 2

[0030] Another parallel, high-efficiency, flexible-cylinder harmonic reducer with an internal outer rotor motor is shown in Figure 4. It provides a schematic diagram comparing the structures of the reducer's dynamic and static components with or without integration. As shown on the right side of Figure 4, when the dynamic and static components are assembled from separate parts, two wave generators 16 of identical dimensions and perpendicular long axes must be tightly fitted at both ends of the motor's outer rotor 14. Flexible bearings 15 are mounted on these wave generators 16, forming a non-circular shape. These bearings are then embedded within the flexible cylinder 13, which has gears at both ends. A pair of deep-groove ball bearings support the outer rotor 14 and the fixed rigid wheel 19. In this case, the word "composite" should be removed from the name. However, the functions and advantages of this flexible-cylinder harmonic reducer are retained, though the radial and axial dimensions are slightly larger, resulting in lower transmission efficiency and a greater number of interfaces in the force or torque transmission path. The manufacturing process is relatively more mature and simpler. At this time, the rotating shell 12 is supported by a pair of angular contact ball bearings 17. The end cover 20 uses screws to position and pre-tighten the angular contact ball bearings 17 on the rigid wheel 19. The rotating shell 12 outputs the amplified rotational torque at a low speed and withstands the radial and axial forces from the outside.

[0031] Example 3

[0032] As shown in Figure 5, the third parallel-type, high-efficiency, composite flexible-cylinder harmonic reducer for an internally mounted external rotor motor provided in this embodiment is still compactly assembled in the radial and axial directions, consisting of an integrated moving component, an integrated static component, and an elastic coupling output member with low axial stiffness and high circumferential stiffness. The integrated moving component comprises a flexible cylinder 11 with integrated flexible bearing outer ring raceways on both inner surfaces, a gear on the outer surface, and a central portion of the same diameter. It is assembled with two wave generators 8 of the same structural dimensions, with mutually perpendicular long axes, and flexible bearing inner ring raceways on the outer surfaces, integrated at both ends of the motor's external rotor. These wave generators are assembled via two identical spherical roller cage assemblies 18. The integrated static component is identical to that shown in Figure 2, but uses a rigid wheel 1 as an internal bevel gear for harmonic meshing at the beveled end faces. To fully utilize the composite elastic material and flared angle at the ends of the flexible cylinder, the internal bevel gear of the rigid wheel 1 meshes with the conical external bevel gears at both ends of the flexible cylinder 11. By utilizing some of the rib material of the flexible bearing's outer raceway, the material required at the ends of the flexible cylinder 11 is reduced, maximizing the meshing area and minimizing deformation energy loss at this location. A toothed coupling 11B, with low axial stiffness near the wall and high circumferential stiffness, meshes with the internal toothed coupling 12B of the rotating housing 12. The rotating housing 12 is supported by a pair of tapered roller bearings 21, which are pre-tightened to the rigid wheel 1 by screws at the end cap 7. The rotating housing 12 delivers amplified torque at low rotational speed while also withstanding external radial and axial forces.

[0033] Example 4

[0034] As shown in Figures 2, 4, and 5, this embodiment provides a parallel-type, high-efficiency, composite flexible-cylinder harmonic speed increaser with an internal outer rotor generator. In this embodiment, the speed increaser comprises an integrated moving component, an integrated static component, and an elastic coupling input member with low axial stiffness and high circumferential stiffness in the radial and axial directions. Its structural composition is identical to that of Embodiments 1-3, except that the internal outer rotor motor is replaced with an internal outer rotor generator. This converts the low-speed, high-torque input of the rotating housing 12 into a high-speed, low-torque output of the generator's outer rotor 8 or 14. This allows a compact mechanical speed increase device to increase low-speed mechanical energy by dozens of times, generating electricity.

[0035] The above describes in detail four preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solution that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. The parallel high-efficiency composite flexible cylinder type harmonic reducer with an internal-external rotor motor is characterized in that By virtue of the orthogonal antisymmetric deformation generated by the middle equal-diameter thin-walled flexible cylinder due to the wave generators with long axes perpendicular to each other installed coaxially at both ends, the two harmonic drive components with the same module and tooth number difference at both ends of the flexible cylinder are used to amplify the torque of half of the same input source in the same proportion. After the amplified torques in the same rotation direction at both ends are superimposed on the cross-section of the constant-circle flexible cylinder, they are output by the variable-stiffness connectors on its outer circle. These two harmonic drive components actually work in parallel with the same proportion of deceleration.

2. The parallel high-efficiency composite flexible cylinder type harmonic reducer with an internal-external rotor motor as described in claim 1, wherein This reducer is compactly composed in the radial and axial directions by an integrated moving component, an integrated static component, and an elastic connection output component with low axial stiffness and high circumferential stiffness. The integrated moving component consists of a flexible cylinder with flexible bearing outer raceways integrated on the inner surfaces at both ends, a gear on the outer surface, and an equal diameter in the middle, and two wave generators with the same structural dimensions and long axes perpendicular to each other and flexible bearing inner raceways on the outer surfaces integrated at both ends of the outer rotor of the motor. They are assembled through two identical ball or spherical roller cage components.

3. The parallel high-efficiency composite flexible cylinder type harmonic reducer with an internal-external rotor motor as claimed in claims 1 and 2, characterized in that, The described integrated static component consists of the inner stator of the motor and two end-cap-shaped rigid gears fixedly connected to both ends of the stator shaft. The module and tooth number difference of the internal gears of the two groups of rigid gears are the same as those of the external gears of the flexible cylinder. The rigid gear teeth and the flexible cylinder gears can be engaged in a harmonic manner in the way of being parallel to the maximum outer expansion angle of the flexible cylinder; they can also be engaged in a harmonic manner on the inclined end face in the way of internal bevel gear engagement to make full use of the elastic material at the end of the flexible cylinder, increase the meshing area, and reduce the deformation energy consumption here.

4. The parallel high-efficiency composite flexible cylinder type harmonic reducer with an internal external rotor motor as claimed in claims 1 and 2, characterized in that, Taking advantage of the fact that the cross-section of the flexible cylinder always remains circular during the working process, that is, there is no radial displacement at each point on the circumference of the cylinder wall of this cross-section, and only there are small-amplitude different deflections, on the outer side of the flexible cylinder wall of this cross-section, the rotational torque is output by means of fixing with a bridge-hole type ridge piece with low axial stiffness and high circumferential stiffness at the near-wall end and high stiffness in all directions at the far-wall end, or a tooth-shaped meshing pair, etc., to reduce the constraint of the output connector on the different small-amplitude deflection deformations at each point on the circumference of the flexible cylinder cross-section, and effectively reduce the constraint energy consumption here. The radial and axial external forces outside the rotational torque output end are borne by a pair of angular contact ball bearings through the rotating housing of the variable-stiffness connector.

5. The parallel high-efficiency composite flexible cylinder type harmonic reducer with an internal-external rotor motor as described in claims 1 to 4, characterized in that, Taking advantage of the fact that each point on the circumference of the flexible cylinder port swings outwards and inwards with the mid-section point on the generatrix where each point is located as the center during the rotational work and the swing value is the largest, that is, the swing values of each point on the axial direction of the teeth of the end spur gear parallel to the axis are not equal. Therefore, the long generatrix of the rigid gear teeth engaged in a parallel-axis harmonic manner should be parallel to the maximum outer expansion angle of the flexible cylinder. In this case, with the help of chamfering at the tooth end, half of the difference between the lengths of the long and short axes of the wave generator is used as the disengagement gap with a value of 2 / 5 or less, and 3 / 5 or more of this length difference is used as the gear meshing height to increase the meshing area. Similarly, and to make full use of the elastic material and outer expansion angle of the composite part at the end of the flexible cylinder, for the harmonic engagement on the inclined end face, internal bevel gear engagement can be used, and the flexible cylinder gear is conical. Since part of the retaining edge material of the flexible bearing outer raceway is borrowed, the material at the end of the flexible cylinder is reduced to maximize the meshing area and reduce the deformation energy consumption of the flexible cylinder here.

6. The parallel high-efficiency composite flexible cylinder type harmonic reducer with an internal-external rotor motor according to claims 1 to 5, characterized in that, Due to the fact that the outer rotor of the motor integrates two wave generators with the same structural dimensions and long axes perpendicular to each other in the moving components, with the help of two ball or spherical roller cage assemblies with the same deformation amount, it is meshed and supported or suspended in the teeth of two rigid wheels by the teeth at both ends of the long axis of the flexible cylinder, and is coaxial with the two rigid wheels; while the axial displacement of the ball or spherical roller cage assembly is restricted by the outward expansion and inward contraction deformations perpendicular to each other at the ports of the flexible cylinder, as well as the non-parallel axis meshing constraint between the axially symmetric rigid wheel and the flexible cylinder teeth; in addition, the rigid rotating housing supported by angular contact ball bearings can assist in restricting the radial and axial displacements of the outer rotor through the variable stiffness coupling outside the middle section of the flexible cylinder. Therefore, there is no need for bearings to support between the stator and rotor of the built-in outer rotor motor.

7. The parallel high-efficiency composite flexible barrel type harmonic reducer with an internal-external rotor motor according to claims 1 to 6, characterized in that, Because the power source, the outer rotor motor, is built inside the flexible cylinder, there is only a torque output end outside the reducer. The whole reducer is like a low-speed high-torque motor with the housing rotating; because there are no rolling bearings between the stator and rotor of the motor; and both the static and moving components have a high degree of integration compared with the original flexible gear type harmonic reducer, which not only reduces the number of parts, but also reduces the number of interfaces in the force or torque transmission path, simplifies the constraints between parts, improves the structural strength of each part, and reduces friction and wear. Therefore, this type of harmonic reducer has a simple, compact structure and small volume.

8. The parallel high-efficiency composite flexible cylinder type harmonic reducer with an internal external rotor motor as claimed in claims 1 to 7, characterized in that, Due to the absence of the structural constraints such as the cup bottom or hollow flanging at the output end of the flexible gear in the original flexible gear type harmonic reducer, there is no energy consumption during their operation; also, because the flexible cylinder and the outer ring of the flexible bearing are combined into one, the wall thickness of the elastic parts required for the processing technology of the original two independent parts but not required during operation is greatly reduced. Therefore, the deformation energy loss of the most core elastic part in the harmonic reducer can also be significantly reduced; compared with the flexible gear type harmonic reducer with only a single harmonic drive component, at the same input power, since the load on the two parallel working harmonic drive components is reduced by half, under the condition of the same flexural rigidity wall thickness of the flexible parts, the wall thickness of the elastic parts of the parallel high-efficiency composite flexible cylinder type harmonic reducer can be less than half of that of the former. All the above characteristics can improve the transmission efficiency of the reducer and reduce the failure rate of the flexible parts.

9. The parallel high-efficiency composite flexible cylinder type harmonic reducer with an internal-external rotor motor as claimed in claims 1 to 7, characterized in that, The ball or spherical roller cage assembly only bears the flexible cylinder deformation and the rigid wheel tooth shape acting force between the high-speed rotating outer rotor and the flexible cylinder raceway. Since the two are only related to the structural dimensions and materials of the flexible cylinder and the output torque, and are internal forces, they are relatively stable and predictable; while the rotating housing support bearings of the variable stiffness coupling bear changing external forces, but their rotational speed is low, within the normal working range of the bearings and with a large installation space. That is to say, from the power input of the high-speed motor to the large reduction ratio output of the reducer, only two pairs of bearings are used to comprehensively complete the deformation reduction, "suspend" the outer rotor of the motor, share different types of loads and work at high and low rotational speeds respectively, with clear division of labor and cooperation in bearing the structural components.

10. The parallel high-efficiency composite flexible cylinder type harmonic reducer with an internal-external rotor motor as described in claims 1 to 7, characterized in that, Even if the moving and stationary components of the speed reducer are assembled from discrete components without corresponding integration, the word "compound" can be removed from the name. However, the functions and advantages of this flexible cylinder type harmonic speed reducer still exist, except that its radial dimension is slightly larger, its transmission efficiency is reduced, and there are a few more interfaces in the force or torque transmission path, while its manufacturing process will be relatively more mature and simple.

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