Electromechanically integrated parallel composite flexible disk-type axial harmonic reducer

Abstract

An electromechanically integrated parallel composite flexible disk-type axial harmonic reducer, of which a moving part consists of a composite flexible disk (18, 35, 80, 120) having two sides respectively integrated with a flexible thrust bearing low-speed moving ring raceway and a flat spur gear and having an integrated variable-stiffness coupling member, and two rolling wave generators (12, 21, 41, 54, 78, 82, 119, 126) fixedly connected to a motor rotor (8, 48, 87, 132) and having the same structural size and axial runouts perpendicular to each other in the circumferential direction, and a static part fixedly consists of two rigid end covers (3, 42, 63, 103) fixedly connected to a flat spur gear (16, 19, 39, 53, 79, 81, 118, 124) and a motor stator (5, 50, 65, 105). Because of the circumferential orthogonal axial symmetric deformation of the shared composite flexible disk (18, 35, 80, 120), halves of input torque of a motor are respectively and synchronously amplified in parallel by two axial harmonic drive assemblies (12, 17, 18, 16 and 21, 20, 18, 19; 41, 49, 35, 39 and 54, 52, 35, 53; 69, 76, 78, 80, 79 and 86, 85, 82, 80, 81; 113, 114, 119, 120, 118 and 128, 127, 126, 120, 124) having the same structural parameters, and are superimposed by means of the integrated variable-stiffness coupling member on the outer or inner circular side of the composite flexible disk (18, 35, 80, 120) and then outputted to a rotary housing (15, 75, 117) or a mandrel (31, 32). The total deformation of a flexible member is reduced because of the shared composite flexible disk (18, 35, 80, 120) and the integrated variable-stiffness coupling member. The elastic deformation forces of the two axial harmonic drive assemblies cancel each other out in the moving part and thus will not be transmitted to a support bearing, thereby reducing friction power consumption.

Description

Electromechanical fusion parallel composite flexible disc type axial harmonic reducer TECHNICAL FIELD

[0001] The present application belongs to the field of mechanical transmission technology, and particularly relates to five kinds of electromechanical fusion parallel composite flexible disc type axial harmonic reducers. The present application proposes the idea of realizing parallel work of two axial harmonic transmission assemblies by means of electromechanical fusion, and reduces the total deformation energy consumption and friction power loss of the reducer by respectively integrating and reducing some static and dynamic parts and reducing the material of the non-working flexible parts, and making the elastic deformation forces in the moving parts offset each other. Since the driving source, i.e. the motor, and the reducer are integrated, the structure of the active axial harmonic reducer is compact, small in size, and high in transmission efficiency. BACKGROUND

[0002] The harmonic reducer has the characteristics of small size, large transmission ratio, high transmission precision, light weight, etc., and is the core transmission component of automatic control devices such as robots, mechanical equipment and medical devices. With more and more devices developing towards automation and intelligence, higher and higher requirements are put forward for the performance of the harmonic reducer. The common commercial harmonic reducers on the market are radial harmonic reducers with single radial harmonic transmission assemblies, and the description of axial harmonic reducers with single axial harmonic transmission assemblies is only found in patents and research papers and other documents [1-4].

[0003] Unlike general transmission devices, the core principle of the harmonic reducer is to use the elastic deformation of the flexible component during work to generate harmonic motion to transmit motion and power. The axial harmonic reducer described in the literature is mainly composed of an axial cam wave generator, a flexible thrust bearing, a flexible disc with a plane gear on one side, and a plane gear rigid disc with the same modulus but a slight tooth difference with the disc gear. The wave generator is an axial concave-convex cam, and the flexible thrust bearing is installed between the wave generator and the non-gear side of the flexible disc. By applying an axial force to compress the three coaxially with two rotational degrees of freedom, the latter two are deformed axially according to the shape of the wave generator, forcing the plane gear teeth on the outer surface of the convex part of the deformed flexible disc to mesh with the plane gear teeth on the rigid disc. Due to the difference in the number of teeth between the flexible and rigid discs, there is a slight tooth difference, so that the plane gear teeth in the concave part of the deformed flexible disc are completely disengaged from the plane gear teeth on the rigid disc. When the wave generator rotates at high speed, the flexible disc produces controllable rotational axial elastic deformation, and the flexible disc that partially meshes with the plane gear on the rigid disc is forced to produce harmonic deformation motion and rotate at low speed, and the amplified rotational torque is transmitted through the integrated variable stiffness connecting piece on the outer or inner circular side of the flexible disc, achieving a large reduction ratio.

[0004] The low-speed dynamic ring of the flexible thrust bearing and the flexible disc with a planar gear are two core flexible parts of the axial harmonic reducer, but they are manufactured as different parts, both of which will retain the flexible part wall thickness material required by the independent part processing technology, but not required during work, but the flexible part wall thickness material not required during work will also produce elastic deformation and consume energy during the work of the reducer. The high-speed dynamic ring of the flexible thrust bearing is manufactured as a circular plane before being pressed against the wave generator, but after being pressed against the axial cam of the wave generator, the high-speed dynamic ring becomes a non-circular and non-planar part and bears the bending stress after being pressed and assembled, and the curvature of the raceway groove of each radial section of the upper raceway will also change due to the change of the non-circular and non-planar shape, thereby affecting the high-speed operation and stress of the bearing rolling element. The pressing and assembly of the separate parts inevitably increases the number of interfaces in the force or torque transmission path, complicates the constraints between the parts, and reduces the structural strength of the parts.

[0005] In the existing flexible disc type harmonic reducer, there is only a single harmonic transmission assembly, i.e., one side of the flexible disc produces harmonic reduction movement and amplifies torque, and the other side of the flexible disc needs to be pressed and fitted with the low-speed dynamic ring of the flexible thrust bearing to produce controllable rotational axial elastic deformation. The axial force for pressing the three parts is actually the reaction force of the axial elastic deformation force of the flexible disc and the flexible thrust bearing, which is inevitably transmitted axially to the input bearing system of the wave generator and the output bearing system of the flexible disc, thereby generating large friction power consumption and heat on the two independent rotation freedom bearing systems. Among them, the axial force that forces the high-speed dynamic ring of the flexible thrust bearing to produce elastic deformation is not required by the main function of the reducer, but it will also be transmitted axially and generate friction power consumption and heat on the two independent rotation freedom bearing systems.

[0006] The above two power consumptions are one of the main reasons for the large starting power and low transmission efficiency of the existing flexible disc type axial harmonic reducer [4], i.e., the essence is to achieve a large reduction ratio with a small reducer by sacrificing transmission efficiency. Again, the axial concave-convex amount of the cam wave generator that determines the meshing and disengagement of the flexible and rigid disc planar gears is generally large, so the axial movement amount between the retainer and the ball of the flexible thrust bearing is large, although grease lubrication is used, the high-speed centrifugal motion of the ball often throws off the lubricating grease, which is easy to cause lubrication failure.

[0007] The planar gears on the flexible and rigid discs in the current flexible disc type axial harmonic reducer are mostly processed as straight gears parallel to the flexible and rigid disc surfaces, thereby causing the contact area between the teeth of the planar gears on the flexible disc and the teeth of the planar gears on the rigid disc to decrease and additional elastic constraints to be generated due to the skew of the teeth on the flexible disc when the teeth are meshed, and the sliding friction and wear of the meshing tooth surfaces are increased. SUMMARY

[0008] In view of the above defects of the prior art, the present application provides five kinds of parallel compound flexible disc type axial harmonic reducers with mechatronic fusion. The core principle is to use the composite flexible disc which has integrated flexible thrust bearing low-speed dynamic ring raceway and plane straight gear on both sides and has an integrated variable stiffness coupling. Due to the rotation of the two rolling wave generators with the same structure size but the axial concave-convex amount perpendicular to each other in the circumferential direction, the orthogonal symmetric deformation is generated. Through the two axial harmonic transmission assemblies with the same modulus and tooth difference which share the composite flexible disc and work in parallel, the high-speed rotating torque input from the motor to the reducer is amplified by half. The amplified two-way low-speed rotating torque is superimposed through the integrated variable stiffness coupling on the outer or inner circle side of the composite flexible disc, and then output through the rotatable shell or mandrel.

[0009] The mechatronic parallel compound flexible disc type axial harmonic reducer is composed of the moving parts of the two axial harmonic transmission assemblies combined on the motor rotor and sharing the composite flexible disc and the integrated variable stiffness coupling, and the static parts of the two parallel axial harmonic transmission assemblies combined on the motor stator, which are compact in radial and axial directions. The moving parts are composed of the composite flexible disc and the two rolling wave generators. In the assembled state, the composite flexible disc generates four bending deformation surfaces with orthogonal symmetric deformation. The radial section of the four intersection lines of the bending deformation surfaces is the original undeformed radial section state. The total deformation of the flexible part is reduced due to the shared composite flexible disc and integrated variable stiffness coupling, and the elastic deformation force is offset in the moving part, which will not be transmitted to the bearing, reducing the friction power consumption.

[0010] There are two forms of rolling wave generator: one is to produce controllable periodic axial wave by axial cam wave generator integrated with flexible thrust bearing high-speed raceway and equal-diameter ball-cage assembly; the other is to produce controllable periodic axial wave by unequal-diameter ball or spherical roller group driven by cage in revolution, but the axial force on all balls or spherical rollers must be borne by the flexible thrust bearing high-speed raceway supported by the intermediate angular contact ball bearing. The former can eliminate the force that must be applied to the conventional split flexible thrust bearing high-speed raceway to produce axial deformation when the reducer is working, but the positions of the balls in the two equal-diameter ball-cage assemblies on both sides of the composite flexible disc will not be opposite to each other at all times, and will be slightly circumferentially misaligned at times, and the support deformation of each ball will vary with the circumferential position on the axial cam wave generator; while the latter not only has no deformation of the flexible thrust bearing high-speed raceway, but also the relative positions of each unequal-diameter ball or spherical roller are fixed at all times, and can form a plurality of circumferentially multi-point rolling outer bracing deformation states, and the deformation at the support of each ball or spherical roller is always constant, and the deformation of each bending deformation surface can be controlled to rotate sequentially in the circumferential direction, and the deformation changes from zero to small to large, and then back to small and back to zero, and then repeats. The former can only be lubricated with grease due to the large axial displacement between the cage and the ball; while the latter can be lubricated with solid oil scheme due to the small axial displacement between the cage and the ball, so as to avoid the centrifugal throwing of the grease by the high-speed centrifugal motion of the ball, and increase the ability to resist abrasive contamination. Since the ball or spherical roller-cage assembly only bears the elastic deformation force of the composite flexible disc and the integrated variable stiffness connecting piece between the high-speed rotating motor rotor and the composite disc raceway, and the meshing force of the bending deformation outer surface gear teeth and the rigid gear teeth of the composite flexible disc, these two forces are only related to the structural size and material of the composite flexible disc and the integrated variable stiffness connecting piece, and the output torque, and are internal forces, which are relatively stable and predictable.

[0011] The stationary part is fixed by two rigid end covers with integrated plane straight bevel gears and motor stator. The two groups of rigid straight bevel gears in parallel have the same modulus and tooth number difference as the two plane gears integrated on both sides of the composite flexible disc, and the rigid gear teeth and the teeth on the bending deformation outer surface of the composite flexible disc are in straight bevel gear meshing mode for harmonic meshing, so as to fully utilize the elastic material on the composite flexible disc after the three functions of deformation, gear meshing and flexible thrust bearing low-speed raceway support of the thin-walled composite flexible disc and the integrated variable stiffness connecting piece are optimized, improve the meshing area and reduce the deformation and friction energy consumption at this point.

[0012] The integrated variable stiffness coupling designed on the outer or inner circle of the composite flexible disc, whether it is a ring or a tooth, is low in axial swing stiffness and high in circumferential torsional stiffness. On the one hand, it helps the composite flexible disc to easily produce two orthogonal symmetric deformation bending deformation surfaces and rotate sequentially along the circumference, effectively reducing the related constraint energy consumption. On the other hand, the two amplified low-speed rotating torques superimposed on it can be reliably output through the rotatable shell or mandrel. The radial and axial external force outside the rotating torque output end is borne by a pair of angular contact ball bearings between the output end and the fixed end cover. Although the external force is changeable, its speed is low, within the normal working condition range of the rolling bearing, and has a large installation space.

[0013] Due to the slightly more number of teeth of the planar straight gear on the composite flexible disc than the number of teeth of the straight bevel gear on the two rigid end covers, in the case of only four bending deformation surfaces of two orthogonal symmetric deformations on the former, if the difference in the number of teeth between the two is an odd multiple of 2, the two straight bevel gears of the latter need to be installed with a circumferential offset of half a tooth to work correctly. However, if the difference in the number of teeth is an even multiple of 2, the latter does not need to be installed with a circumferential offset. If the composite flexible disc is forced to produce an even number of bending deformation surfaces greater than 4, although the axial concave-convex amount of the rolling wave generator may not be circumferentially orthogonal, as long as the adjacent bending deformation surfaces are axially symmetric deformations after rotating an angle of 360° / the number of even bending deformation surfaces, they can work with the principle of the parallel composite flexible disc type axial harmonic reducer of electromechanical fusion.

[0014] For motors with short rotors and large air gaps, due to the two rolling wave generators in the moving part, which have the same structure and size but the axial concave-convex amount is perpendicular to each other in the circumferential direction, the two ball-retainer assemblies on both sides of the composite flexible disc are supported or suspended by the teeth on the four bending deformation surfaces of the two orthogonal symmetric deformations of the composite flexible disc, and are coaxial with the two rigid straight bevel gears. The axial displacement of the ball-retainer assembly is constrained by the orthogonal symmetric deformation bending surface of the composite flexible disc, and the inclined end surface engagement between the two rigid straight bevel gears and the planar gear of the composite flexible disc. In addition, the rigid rotating shell or mandrel supported by the angular contact ball bearing can assist in constraining the radial and axial displacement of the moving part and the motor rotor through the integrated variable stiffness coupling via the composite flexible disc. Therefore, a pair of deep groove ball bearings is no longer needed to support between the stator and the rotor of the motor, thereby reducing the number of bearings required, simplifying the support structure of the reducer, and reducing unnecessary friction loss and temperature rise. The separation of the motor compartment and the reducer compartment can be solved by the sealing ring between the moving part and the end cover. The entire reducer is like a low-speed large-torque motor with a rotating shell or mandrel.

[0015] Compared with the existing flexible disc type axial harmonic reducer, under the same input power, the two harmonic transmission assemblies of the parallel type composite flexible disc type axial harmonic reducer work in parallel, the load is reduced by half, the total elastic deformation energy consumed during work is relatively reduced due to sharing a set of composite flexible disc and an integrated variable stiffness connecting piece, the wall thickness of the flexible disc and the two new forms of rolling wave generator are reduced due to the processing technology required but not needed during work, and the multidirectional friction between the independent parts during work is eliminated, so under the same flexible disc bending and torsional stiffness wall thickness conditions, the latter can effectively improve the transmission efficiency of the reducer, reduce the temperature rise during work and the failure rate of the flexible part.

[0016] Even if the moving and static parts of the reducer are assembled with separate parts without corresponding integration, the composite two words can be removed from the name, but the function and advantage of the parallel type flexible disc type axial harmonic reducer of the mechanical and electrical integration are all in, only the radial and axial dimensions are larger, there are several interfaces in the force or torque transmission path, the transmission efficiency is reduced, but the manufacturing process is relatively mature and simple.

[0017] The reducer can also be used in reverse to become a speed increaser, that is, the low-speed large-torque input can be converted into high-speed low-torque output, so as long as the integrated motor is replaced by a generator, a parallel type composite flexible disc type axial harmonic speed increaser can be realized, thereby the low-speed mechanical energy is speeded up and converted into electrical energy output. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic diagram of the structure of the flexible disc type axial harmonic assembly and the elastic deformation engagement of the flexible and rigid disc bending deformation surfaces;

[0019] Figure 2 is a schematic diagram of three radial cross-sectional structures of a parallel type composite flexible disc type axial harmonic reducer of a preferred embodiment of the present application, which is an internal rotor motor with a first form of rolling wave generator;

[0020] Figure 3 is a schematic diagram of the bending deformation and stress of the axial cam wave generator integrated with the flexible thrust bearing high-speed dynamic ring raceway in the first form of rolling wave generator of the present application and the composite flexible disc with the integrated ring-shaped variable stiffness connecting piece on the outer circular side of the low-speed dynamic ring raceway and the plane spur gear each integrated with the flexible thrust bearing on both sides in three radial cross sections;

[0021] Figure 4 is a schematic diagram of three radial cross-sectional structures of a parallel type composite flexible disc type axial harmonic reducer of the present application using the first form of rolling wave generator and placing the reducer inside the shaft of an internal rotor motor;

[0022] Figure 5 is a schematic diagram of three radial cross-sectional structures of a parallel type composite flexible disc type axial harmonic reducer of the present application using an internal rotor motor with a second form of rolling wave generator.

[0023] Fig. 6 is a schematic diagram of the ball set-retainer structure of the relative circumferential position between the balls of two ball sets of different diameters driven by the retainer in revolution in the second form of the rolling wave generator of the present application;

[0024] Fig. 7 is a schematic diagram of the three radial cross-sectional structures of the parallel compound flexure plate type axial harmonic reducer of the built-in outer rotor motor with integrated tooth profile variable stiffness couplings in the present application.

[0025] Fig. 8 is a schematic diagram of the cross-sectional structure of the parallel compound flexure plate type axial harmonic reducer of the built-in outer rotor motor of two second forms of the rolling wave generator with balls of different diameters in the present application.

[0026] Fig. 9 is a schematic diagram of the two radial cross-sectional structures of the parallel compound flexure plate type axial harmonic reducer of the built-in outer rotor motor without bearings between the stator and the rotor in the present application. DETAILED DESCRIPTION

[0027] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects more clearly understood, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0028] In the following description, for the purpose of explanation and not limitation, specific details are set forth, such as particular internal procedures, techniques, in order to thoroughly understand the embodiments of the present application. However, it should be clear to those skilled in the art that the present application can also be implemented 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 application with unnecessary details.

[0029] As shown in Fig. 1a, the flexible disc type axial harmonic reducer is composed of an axial cam wave generator 01, a flexible thrust bearing 02, a flexible disc 03 with plane gear on one side and a rigid disc 04 with plane gear, that is, only one set of axial harmonic transmission assembly. Among them, the flexible thrust bearing 02 is installed between the wave generator 01 and the flexible disc 03, and the three are coaxially compressed with two rotational degrees of freedom by applying axial force, and the axial deformation is generated according to the axial cam shape of the wave generator 01, forcing the plane gear teeth on the two convex parts of the deformed flexible disc 03 as shown in the 0° view of Fig. 1b to mesh with the plane gear teeth on the rigid disc 04 at the same time. Because the number of plane gear teeth on the flexible disc 03 and the rigid disc 04 is different, there is a small tooth difference, so that the plane gear teeth in the two concave parts of the deformed flexible disc 03 are completely disengaged from the plane gear teeth on the rigid disc 04 as shown in the 90° view of Fig. 1b; when the wave generator 01 rotates at high speed, the flexible disc 03 can produce controllable rotational axial elastic deformation, and the flexible disc 03 which is partially engaged with the plane gear on the rigid disc 04 is forced to produce harmonic deformation motion and rotate at low speed. The latter transmits the amplified rotating torque through the integrated variable stiffness connecting piece on the inner circle side to achieve the purpose of large speed reduction ratio, so this kind of harmonic reducer has the five shortcomings described in the background art.

[0030] In view of the above problems, the present application will describe five embodiments of the mechatronic parallel composite flexible disc type axial harmonic reducer.

[0031] Example one

[0032] As shown in Fig. 2, the embodiment provides a parallel compound flexible disc type axial harmonic reducer with built-in outer rotor motor of the first form rolling wave generator. In the embodiment, the reducer is composed of integrated moving parts and static parts in radial and axial compactness. The integrated moving parts are composed of the composite flexible disc 18 with the flexible thrust bearing low-speed dynamic ring raceway and the plane spur gear integrated on both sides, and the outer circular side is an integrated ring piece deformation stiffness coupling piece, and the two rigid end covers 3 with the bolt 14 fixedly connected with the plane straight bevel gears 16 and 19 are fixed by a pair of nuts 2 at both ends of the stator shaft 1 provided with the motor inner stator 5, constituting the static parts. The moving parts of the reducer are radially supported on the two end covers 3 by a pair of deep groove ball bearings 9 with sealing rings, which also separate the motor cabin from the reducer cabin; since the elastic deformation forces on the two axial harmonic transmission assemblies 12, 17, 18, 16 and 21, 20, 18, 19 sharing the composite flexible disc 18 and working in parallel are mutually offset in the moving parts, there is no axial force on the deep groove ball bearings 9. The integrated ring piece deformation stiffness coupling piece on the outer circular side of the composite flexible disc 18 superimposes the amplified low-speed rotating torques of the left and right two paths and outputs to the rotating two housings 15 through the bolt 22; the radial and axial external forces on the housings 15 are borne by a pair of angular contact ball bearings 13 between the housings 15 and the rigid end covers 3, which are positioned and pre-tightened on the rigid end covers 3 by the gland 11 through the bolt 10.

[0033] As shown in Fig. 2, the two rigid plane straight bevel gears 16 and 19 and the plane gears on both sides of the composite flexible disc 18 have the same modulus and tooth number difference, and the three are in straight bevel meshing mode to simultaneously perform harmonic meshing on the four curved deformation outer surfaces of the composite flexible disc 18 in pairs of orthogonal directions, i.e., the two harmonic transmission assemblies are in parallel to perform the same proportional reduction work. The controllable periodic axial wave is completed by the axial cam wave generators 12 and 21 integrated with the flexible thrust bearing high-speed dynamic ring raceway and the equal-diameter ball-cage assemblies 17 and 20, which is the first form rolling wave generator. Although the balls in the two equal-diameter ball-cage assemblies roll in the same direction, their positions do not always face each other across the composite flexible disc 18, and sometimes they are slightly circumferentially misaligned, and the support deformation of each ball changes with the circumferential position on the axial cam wave generator. The power line 4 penetrates the wall hole of the left end cover 3 and is electrically connected with the inner stator 5.

[0034] Fig. 3a shows the structural cross-sectional view of the axial cam wave generators 16 and 19 in the first form of rolling wave generator with the high speed raceway of the flexible thrust bearing integrated into the high speed raceway of the dynamic ring, so that the force that must be applied to the high speed raceway of the dynamic ring on the side of the wave generator 01 in the conventional separate flexible thrust bearing 02 as shown in Fig. 1 to produce the axial deformation during the operation of the speed reducer can be eliminated; Fig. 3b shows the bending deformation and force of the composite flexible disc 18 in three radial cross sections, where Fg1 is the force of the rigid plane straight bevel gear 16, F1 is the force of the equal diameter ball-cage assembly 17, F2 is the force of the equal diameter ball-cage assembly 20, and Fg2 is the force of the rigid plane straight bevel gear 19; Fig. 3c shows the three-dimensional view of the four bending deformation surfaces of the two-by-two orthogonal symmetric deformation of the composite flexible disc 18 (the two plane gears are not shown), since the axial concave-convex amount of the rolling wave generators 16 and 19 is circumferentially orthogonal, the adjacent bending deformation surfaces on the composite flexible disc 18 are axially symmetrically deformed after rotating 90° in the circumferential direction; Fig. 3d shows the 45°-225° radial cross-sectional view of two of the four boundary lines between the four bending deformation surfaces in Fig. 3c, which should be the original undeformed radial cross-sectional state, that is, the 45° unstressed state of the composite flexible disc 18 in Fig. 3b; since the number of teeth of the plane straight gear on the composite flexible disc 18 is slightly more than the number of teeth of the straight bevel gears 16 and 19 on the two rigid end covers, in the case that the former only produces four bending deformation surfaces of two-by-two orthogonal symmetric deformation, if the difference between the number of teeth of the two is an odd multiple of 2, the latter two straight bevel gears 16 and 19 need to be installed with a circumferential offset of half a tooth to work correctly; but if the difference between the number of teeth is an even multiple of 2, the latter does not need to be installed with a circumferential offset.

[0035] Example Two

[0036] Another three radial cross-section structure of parallel compound flexspline type axial harmonic reducer using the first form rolling wave generator is shown in Fig. 4. This embodiment is contrary to the built-in outer rotor motor in the first embodiment, and the reducer is placed inside the shaft of the inner rotor motor. The reducer is still composed of integrated moving parts and static parts in the radial and axial directions. The integrated moving parts are composed of a compound flexspline 35 with an integrated ring piece-shaped deformation stiffness coupling on the inner circular side, two wave generators 41 and 54 with the same structure size but the axial concave-convex amount perpendicular to each other in the circumferential direction, and integrated with flexible thrust bearing high-speed moving ring raceways on the axial cam end face, which are bolted 44 to the two ends of the motor inner rotor 48 embedded with permanent magnets 47, and assembled by two identical equal-diameter ball-cage assemblies 49 and 52. The two rigid end covers 42, which are bolted 36 with flat straight bevel gears 39 and 53, are fixed by two sets of bolts 45 at both ends of the stator shell 46 with the motor outer stator 50, constituting the static parts. The moving parts of the reducer are radially supported on the two end covers 42 by a pair of deep groove ball bearings 40 with sealing rings, which also separate the motor compartment from the reducer compartment; because the elastic deformation forces on the two axial harmonic transmission assemblies 41, 49, 35, 39 and 54, 52, 35, 53, which share the compound flexspline 35 and work in parallel, cancel each other out in the moving parts, there is no axial force on the deep groove ball bearings 40. The integrated ring piece-shaped deformation stiffness coupling on the inner circular side of the compound flexspline 35 superimposes the amplified low-speed rotating torques from the left and right sides and outputs them to the rotating two mandrels 31 and 32 through the pin 51; the mandrels 31 and 32 are axially pressed by the nut 33, and the radial and axial external forces on them are borne by a pair of angular contact ball bearings 34 between the two rigid end covers 42, which are positioned and pre-tightened on the rigid end covers 42 by the gland 38 through the bolts 37.

[0037] As shown in Fig. 4, the modulus and number of teeth of the two rigid flat straight bevel gears 39 and 53 and the flat gears on both sides of the compound flexspline 35 are the same, and the three are in straight bevel meshing mode on the four curved deformed outer surfaces of the compound flexspline 35, which are orthogonal to each other, to simultaneously perform harmonic meshing, i.e. the two harmonic transmission assemblies work in parallel at the same reduction ratio as shown in the functional block diagram. The controllable periodic axial wave is completed by the first form rolling wave generator composed of the axial cam wave generators 41 and 54 integrated with flexible thrust bearing high-speed moving ring raceways and the equal-diameter ball-cage assemblies 49 and 52, and the power supply line 43 enters the wall hole of the left end cover 42 to electrically connect with the inner stator 50.

[0038] Embodiment Three

[0039] As shown in Fig.5, the parallel compound flexspline type axial harmonic reducer with the built-in outer rotor motor of the second form rolling wave generator provided by the embodiment still consists of integrated moving parts and stationary parts in radial and axial compactness. The integrated moving parts are composed of the compound flexspline 80 with the integrated ring piece shaped deformation stiffness coupling on the outer side, the two rolling wave generators 78 and 82 of the same structure size but the axial concave-convex amount perpendicular to each other in the circumference of the two unequal diameter ball sets driven by the cage to revolve around, and the flexible thrust bearing high speed moving ring 76 and 85 supported by the intermediate angular contact ball bearing 69 and 86, which are fixed on the two moving part seats 68 by the screws 74 and 83 respectively, and the other moving ring of the intermediate angular contact ball bearing 69 and 86 is also fixed on the two moving part seats 68 in radial and axial directions respectively. The two rigid end covers 63 with the flat spur gears 79 and 81 fixed by the bolts 77 are fixed on the two ends of the stator shaft 61 with the motor inner stator 65 by a pair of nuts 62, which constitute the stationary parts. The moving parts of the reducer are supported by a pair of deep groove ball bearings 70 with sealing rings on the two end covers 63 in radial direction, which also separate the motor cabin from the reducer cabin. Since the elastic deformation forces on the two axial harmonic transmission assemblies 69, 76, 78, 80, 79 and 86, 85, 82, 80, 81 sharing the compound flexspline 80 and working in parallel cancel each other out in the moving parts, there is no axial force on the deep groove ball bearings 70. The integrated ring piece shaped deformation stiffness coupling on the outer side of the compound flexspline 80 superimposes the amplified low speed rotating torques of the left and right two paths and outputs to the two rotating housings 75 through the bolts 84; the radial and axial external forces on the housings 75 are borne by a pair of angular contact ball bearings 73 between the rigid end covers 63, which are positioned and pre-tightened on the rigid end covers 63 by the gland 72 through the bolts 71.

[0040] As shown in Fig.5, the two rigid flat spur gears 79 and 81 and the flat gears on the two sides of the compound flexspline 80 have the same modulus and tooth number difference, and the three are in straight bevel gear meshing mode to simultaneously perform harmonic meshing on the four curved deformation outer surfaces of the compound flexspline 80 in pairs of orthogonal directions, i.e. the two harmonic transmission assemblies work in parallel at the same scale as shown in the functional block diagram. The controllable periodic axial wave is completed by the two rolling wave generators 78 and 82 of the unequal diameter ball sets driven by the cage to revolve around, and the flexible thrust bearing high speed moving ring 76 and 85 supported by the intermediate angular contact ball bearing 69 and 86, which is the second form rolling wave generator. The flexible thrust bearing high speed moving ring bears the axial forces of the balls of different diameters but has no bending deformation, and the balls in the two unequal diameter ball-cage assemblies 78 and 82 also roll in the same direction through the compound flexspline 80, but the circumferential relative positions between the balls of different diameters are fixed at all times. The power supply line 64 penetrates the wall hole of the left end cover 63 and is electrically connected with the inner stator 65.

[0041] Figure 6 is a schematic diagram of the circumferential relative position between the balls of two sets of unequal diameter balls driven by the cage in the second form of the rolling wave generator of the present application. The two sides of the low speed dynamic race of the flexible thrust bearing integrated on both sides of the composite flexible disc 80, the diameter and circumferential position of the balls of the two sets of unequal diameter balls 78 and 82 driven by the cage must be designed according to the bending deformation surfaces of the composite flexible disc 80. The circumferential distance between the balls can be unequal. In addition to the unequal diameter balls that press the composite flexible disc 80 in the current direction to generate two bending deformation surfaces, there are also unequal diameter balls that are supported in a staggered manner to generate two bending deformation surfaces in the orthogonal direction. The two sides of each of the four bending deformation surfaces on the composite flexible disc 80 can form multiple sets of bending deformation states of rolling and rolling with three-point support in the circumferential direction. The deformation at each three-point support remains constant, and the circumferential order of rotation of each bending deformation surface can be controlled. The deformation changes from zero to small to large, then back to small and back to zero, and the cycle repeats. Unlike the cage in the first form of the rolling wave generator, which can produce axial bending and a large amount of axial movement between the cage and the balls, the cage in this rolling wave generator does not have axial bending, and the axial force or axial movement between the cage and the balls is independent of the axial concave-convex amount of the rolling wave generator (i.e., the change in the diameter of the balls). Therefore, solid oil can be used for lubrication to avoid the centrifugal throwing of the lubricating grease by the high-speed rolling of the balls and to increase the ability to resist abrasive particle contamination.

[0042] Example Four

[0043] As shown in Fig. 7 and Fig. 8a and Fig. 8b, the embodiment provides a parallel type composite flexible disc axial harmonic reducer of the built-in outer rotor motor with three types of integrated tooth profile variable stiffness couplings. In this embodiment, the reducer is also composed of integrated moving parts and static parts in the radial and axial compact. The integrated moving parts are composed of the composite flexible disc 120 or 120A or 120B of the outer circular side integrated tooth profile variable stiffness coupling, the second form of the rolling wave generator 119 and 126 (or 119A and 126A, or 119B and 126B) of two unequal diameter balls or spherical rollers of the same structure size but the axial concave-convex amount is perpendicular to each other in the circumferential direction, and the two groups are driven to revolve by the cage, and the flexible thrust bearing high-speed moving ring 114 and 127 (or 114A and 127A, or 114B and 127B) supported by the intermediate angular contact ball bearing 113 and 128, which are combined together, and the two unequal diameter balls or spherical rollers of the rolling wave generator 119 and 126 (or 119A and 126A, or 119B and 126B) cage assembly are fixed on the two moving part seats 108 by screws 110 respectively, and the other moving ring of the intermediate angular contact ball bearing 113 and 128 is also fixed radially and axially on the two moving part seats 108 respectively. The two rigid end covers 103 with the flat straight bevel gears 118 and 124 fixed by bolts 116 are fixed by a pair of nuts 102 on the two ends of the stator shaft 101 with the motor inner stator 105, which constitutes the static part. The moving parts of the reducer are supported radially on the two end covers 103 by a pair of deep groove ball bearings 109 with sealing rings, which also separate the motor compartment from the reducer compartment; because the elastic deformation forces on the two axial harmonic transmission assemblies 113, 114, 119, 120, 118 and 128, 127, 126, 120, 124 (or 113, 114A, 119A, 120A, 118 and 128, 127A, 126A, 120A, 124, or 113, 114B, 119B, 120B, 118 and 128, 127B, 126B, 120B, 124) working in parallel share the composite flexible disc 120 or 120A or 120B, the axial force on the deep groove ball bearing 109 is zero.

[0044] As shown in Fig. 7 and Fig. 8, the inner circle side of the composite flexible disc 120 or 120A or 120B is mounted on the outer ring of the intermediate deep groove ball bearing 130 by two compression rings 121 and screws 129, and the inner ring of the bearing 130 is axially positioned and differentially rotated with the outer rotor 132 of the motor by means of two unequal diameter ball or spherical roller assemblies 119 and 126 (or 119A and 126A, or 119B and 126B), and the resultant force of each axial force acting on the bearing 130 is zero; while the integrated tooth-shaped variable stiffness coupling on the outer circle side will superimpose two amplified low-speed rotational torques, which are output to the housing 117 through the meshing of the inner ring gear 122 with the same number of teeth as the tooth-shaped coupling in the rotating housing 117, and the inner ring gear 122 is fixed in the rotating housing 117 by two groups of screws 123. The radial and axial external forces on the housing 117 are borne by a pair of angular contact ball bearings 115 between the two rigid end covers 103, the left end bearing 115 is positioned and pre-tightened on the left end cover 103 by the gland 112 through the bolt 111, and the right end bearing 115 is positioned and pre-tightened on the right end cover 103 by the positioning sleeve 125 and the gland 112 through the bolt 111. The arc-topped straight gears on the outer circle side of the composite flexible disc 120 or 120A or 120B for outputting low-speed rotational torque and the flat straight gears on both sides thereof can be of the same tooth type, or different tooth types and different tooth numbers. The former is beneficial to machining, installation and bending deformation of two orthogonal directions, while the latter increases the machining difficulty, but can increase the meshing area, reduce the friction and wear during the swinging of the composite flexible disc, and improve the transmission accuracy from the toothless meshing angle (such as the spline form meshing).

[0045] As shown in Fig. 7 and Fig. 8, two rigid plane straight bevel gears 118 and 124 have the same modulus and tooth number difference with the plane gears on both sides of the composite flexible disc 120 or 120A or 120B, and the three are in straight bevel meshing on the two orthogonal four curved deformed outer surfaces of the composite flexible disc 120 or 120A or 120B at the same time, that is, the two harmonic transmission assemblies shown in the function block diagram in Fig. 7 are actually in parallel to perform the same proportional speed reduction work. The controllable periodic axial wave is completed by the rolling wave generator 119 and 126 (or 119A and 126A, or 119B and 126B) of the two unequal diameter ball or spherical roller groups driven by the retainer to revolve, and the flexible thrust bearing high-speed raceway 114 and 127 (or 114A and 127A, or 114B and 127B) supported by the intermediate angular contact ball bearing, which is also the second form of rolling wave generator, but the axial force on all balls or spherical rollers must be borne by the flexible thrust bearing high-speed raceway supported by the intermediate angular contact ball bearing 113 and 128, while the radial force of the spherical roller is shown in Fig. 8a and Fig. 8b, which is borne by the stop edge of the flexible thrust bearing high-speed raceway 114A and 127A (or 114B and 127B). The two unequal diameter balls or spherical rollers in the retainer assembly 119 and 126 (or 119A and 126A, or 119B and 126B) in the three types of speed reducers revolve in the same direction through the composite flexible disc 120 or 120A or 120B, but the circumferential relative position between the two unequal diameter balls or spherical rollers is fixed at all times. The power line 104 is inserted from the wall hole of the left end cover 103 and electrically connected with the inner stator 105.

[0046] As shown in Fig. 7 and Fig. 8, the flexible thrust bearing low-speed raceway integrated on both sides of the composite flexible disc 120 or 120A or 120B is parallel to the composite flexible disc surface, and its two sides are designed according to the curved deformation surface of the composite flexible disc 120 or 120A or 120B, that is, the size of the curvature of each ball or spherical roller and the circumferential position of the two unequal diameter ball or spherical roller groups 119 and 126 (or 119A and 126A, or 119B and 126B) driven by the retainer to revolve in the same direction must be designed according to the curved deformation surface of the composite flexible disc 120 or 120A or 120B, and the circumferential spacing of each ball or spherical roller can be unequal, but it is only supported by the rolling of the two unequal diameter ball or spherical roller groups in the same direction, that is, there is no unequal diameter ball in Fig. 6 that supports the orthogonal direction to produce two curved deformation surfaces. The deformation amount at the contact between each ball or spherical roller and the composite flexible disc 120 or 120A or 120B is always constant, so that the curved deformation surface rotates in sequence along the circumference, and the deformation amount changes from zero to small to large, then back to small and back to zero, and so on. Therefore, solid oil scheme can still be used for lubrication to avoid the high-speed centrifugal motion of the ball or spherical roller throwing off the lubricating grease, and to increase the ability to resist abrasive particle pollution.

[0047] Example Five

[0048] As shown in Fig. 9, the embodiment provides a parallel compound flexible disc type axial harmonic reducer of built-in outer rotor motor with inter-rotor supporting bearing improved on the basis of embodiment one, mainly aiming at the motor with short rotor and large air gap. In the embodiment, the integrated moving part is composed of a composite flexible disc 18 with an integrated ring piece deformation stiffness coupling on the outer side, two rigid end covers 3B with flat straight bevel gears 16B and 19B fixed by bolts 14, and a pair of nuts 2 fixed on the two ends of the stator shaft 1B with the motor inner stator 5B installed, constituting the static part. The separation problem between the motor cabin and the reducer cabin is solved by two sealing rings 9B between the moving and static parts of the reducer; the integrated ring piece deformation stiffness coupling on the outer side of the composite flexible disc 18 superimposes the amplified low-speed rotating torque of the left and right two paths and outputs it to the rotating two housings 15B through bolts 22B; the radial and axial external force on the housing 15B is borne by a pair of angular contact ball bearings 13 between the rigid end cover 3B, which are positioned and pre-tightened on the two rigid end covers 3B by the gland 11 through bolts 10, while the power line 4 enters the wall hole of the left end cover 3B and is electrically connected with the inner stator 5B.

[0049] The elastic deformation forces on the two axial harmonic drive assemblies 12B, 17, 18, 16B and 21B, 20, 18, 19B sharing the composite flexspline 18 and working in parallel cancel each other out in the moving parts. Referring to the composite flexspline deformation three-dimensional schematic diagram (without the two face-helical gears) and the 0°-180° and 90°-270° radial cross-sectional views of FIGS. 3b and 3d, the moving parts, due to the two rolling wave generators 12B and 21B of the same structure and size but with the axial concave-convex amount perpendicular to each other in the circumferential direction, are supported or suspended in the teeth of the two rigid straight bevel gears 16B and 19B by the two identical structure balls-retainer assemblies 17 and 20 on both sides of the low-speed moving ring raceway of the integrated flexible thrust bearing of the composite flexspline 18, and are coaxial with the two rigid straight bevel gears 16B and 19B, with the teeth of the two rigid straight bevel gears 16B and 19B, the axial displacement of the ball-retainer assemblies 17 and 20 being constrained by the orthogonal symmetric deformation of the composite flexspline 18, and the straight bevel gear meshing between the teeth of the two rigid straight bevel gears 16B and 19B and the planar gears on the composite flexspline 18 being constrained. In addition, the two rigid rotating housings 15B supported by the angular contact ball bearing 13 can assist in constraining the radial and axial displacement of the moving parts and the motor rotor through the composite flexspline 18 via the integrated variable stiffness coupling, so that a pair of deep groove ball bearings is no longer needed to support between the stator 5B and the rotor 8B of the motor, thereby reducing the number of bearings needed, simplifying the support structure of the reducer, and reducing unnecessary friction loss and temperature rise. In this way, the large reduction ratio output from the integrated high-speed motor outer rotor 8B power input to the reducer housing 15B is only completed by a pair of shared low-speed moving ring flexible thrust bearings 12B, 17, 18 and 21B, 20, 18, and a pair of angular contact ball bearings 13, which can comprehensively complete the deformation reduction, support the moving parts and the motor outer rotor 8B, share the different nature of the internal and external loads, and work at high and low speeds, respectively, with clear division of labor and cooperation in bearing each moving component.

[0050] The above detailed five preferred embodiments of the present application, in fact, some of the inventive concepts between them can be used interchangeably, such as two rolling wave generators; for example, embodiment five can also be used in embodiments two to four; if forced to composite flexible disc to produce more than 4 even bending deformation surface, although the axial concave-convex amount of rolling wave generator can not be circumferentially orthogonal, as long as the adjacent bending deformation surface is axially symmetric deformation after rotating 360° / even number of bending deformation surface angle, can be used with the principle of electromechanical fusion parallel composite flexible disc type axial harmonic reducer work, etc. Even if the moving and static parts of the reducer are assembled with discrete parts without corresponding integration, the composite two words can be removed from the name, but the function and advantages of the electromechanical fusion parallel composite flexible disc type axial harmonic reducer are the same, only the radial and axial dimensions are larger, there are several interfaces in the torque transmission path, the transmission efficiency is reduced, but the manufacturing process is relatively mature and simple. Undoubtedly, the reducer can also be used in reverse to become a speed increaser, that is, it can convert low-speed large-torque input into high-speed low-torque output, so as long as the integrated motor is replaced by a generator, a parallel composite flexible disc type axial harmonic speed increaser can be realized, thereby increasing the speed of low-speed mechanical energy and converting it into electrical energy output.

[0051] It should be understood that those of ordinary skill in the art can make many modifications and changes to the present application without creative labor based on the concept of the present application. Therefore, any technical solution that can be obtained by logical analysis, reasoning or limited experiments by those skilled in the art based on the concept of the present application on the basis of the prior art shall be within the protection scope determined by the claims. REFERENCES

[0052] [1] Buchanan, Jr., H. C., 1970, “Face Planocentric Speed Reduction Unit and Motor”, U.S. Pat. No. 3,525,890

[0053] [2] Xin Hongbing, Zheng Weizhi and Cao Shengyu, 2005, “Face Harmonic Motor”, Chinese Invention Patent CN1592073A

[0054] [3] Krisch, R., 2007, “Investigation of the meshing conditions of a flat wheel harmonic gear drive”, Proc. ASME 2007 Inter. Design Eng. Tech. Conf. & Computers and Infor. in Eng. Conf., September 4-7, 2007, Las Vegas, Nevada, USA.

[0055] [4] Goncfalvi, B., Offra, G. and Krisch, R., 2021, “Development and manufacturing of an experimental flat wheel strain wave gear unit at K.K.K. 99 Ltd.”, Design of Machines and Structures, Vol. 11, No. 2, pp. 14–20.

Claims

1. An electromechanically fused parallel compound flexspline type axial harmonic reducer, characterized in that, By means of two composite flexible discs which have integrated flexible thrust bearing low-speed dynamic raceway and plane straight gear on both sides respectively and have integrated variable stiffness coupling, due to the circumferential orthogonal axial symmetry deformation (hereinafter referred to as: orthogonal symmetry deformation) of the two rolling wave generators which are of the same structure size but the axial concave-convex amount is perpendicular to each other in the circumferential direction and are fixed on both ends of the motor rotor, through two axial harmonic drive assemblies which have the same modulus and the same difference in the number of teeth and work in parallel, the half of the high-speed rotating torque input by the motor to the reducer is amplified in the same proportion respectively; the amplified two low-speed rotating torques are superimposed through the integrated variable stiffness coupling on the outer or inner circular side of the composite flexible disc and are output through the rotatable shell or mandrel.

2. The electromechanically fused parallel composite flexspline axial harmonic reducer of claim 1, wherein, When the reducer is built-in outer rotor motor, the moving part is the composite flexible disc with integrated ring piece variable stiffness coupling on the outer circular side, and the two rolling wave generators which are of the same structure size but the axial concave-convex amount is perpendicular to each other in the circumferential direction and have integrated flexible thrust bearing high-speed dynamic raceway on the axial cam end face are fixed on both ends of the motor outer rotor and are assembled by two same equal-diameter ball-cage assemblies; the two rigid end covers fixed with plane straight bevel gears are fixed on the inner stator of the motor to form the static part; the moving part of the reducer and the motor outer rotor are radially supported on the two end covers by a pair of deep groove ball bearings with sealing rings, which also separate the motor cabin from the reducer cabin; because the elastic deformation forces on the two axial harmonic drive assemblies which share the composite flexible disc and work in parallel cancel each other out in the moving part, there is no axial force on the deep groove ball bearing; the left and right amplified low-speed rotating torques are superimposed through the integrated ring piece variable stiffness coupling on the outer circular side of the composite flexible disc and are output to the rotating shell through bolts; the radial and axial external forces on the shell are borne by a pair of angular contact ball bearings between the shell and the fixed end cover.

3. The electromechanically fused parallel composite flexspline axial harmonic reducer of claim 1 wherein, When the reducer is placed inside the inner rotor motor shaft, the moving part is the composite flexible disc with integrated ring piece variable stiffness coupling on the inner circular side, and the two rolling wave generators which are of the same structure size but the axial concave-convex amount is perpendicular to each other in the circumferential direction and have integrated flexible thrust bearing high-speed dynamic raceway on the axial cam end face are fixed on both ends of the motor inner rotor hollow shaft and are assembled by two same equal-diameter ball-cage assemblies; the two rigid end covers fixed with plane straight bevel gears are fixed on the outer stator of the motor to form the static part; the moving part of the reducer and the motor inner rotor are radially supported on the two end covers by a pair of deep groove ball bearings with sealing rings, which also separate the motor cabin from the reducer cabin; because the elastic deformation forces on the two axial harmonic drive assemblies which share the composite flexible disc and work in parallel cancel each other out in the moving part, there is no axial force on the deep groove ball bearing; the two amplified low-speed rotating torques are superimposed through the integrated ring piece variable stiffness coupling on the inner circular side of the composite flexible disc and are output to the rotating mandrel through pins, and the radial and axial external forces on the mandrel are borne by a pair of angular contact ball bearings between the mandrel and the fixed end cover.

4. The electromechanically fused parallel compound flexspline axial harmonic reducer of claim 1 or 2 or 3, wherein, The flexible thrust bearing low-speed dynamic ring raceway material integrated on both sides of the composite flexible disc is much less than the conventional separate flexible thrust bearing low-speed dynamic ring raceway material, so that the elastic deformation energy consumption during operation can be reduced; the flexible thrust bearing high-speed dynamic ring raceway integrated on the axial cam end surface of the wave generator can eliminate the force that must be applied to the conventional separate flexible thrust bearing high-speed dynamic ring to generate axial deformation during operation of the speed reducer; the two equal-diameter balls in the ball-retainer assembly on both sides of the composite flexible disc roll in the same direction, but the positions are not always opposite to each other, and sometimes there is a small circumferential misalignment, and the support deformation of each ball changes with the circumferential position on the axial cam wave generator; the axial force or axial displacement between the retainer and the ball, or the axial bending degree of the retainer is determined by the axial concave-convex amount of the cam wave generator; the controllable periodic axial wave is completed by the axial cam wave generator integrated with the flexible thrust bearing high-speed dynamic ring raceway and the equal-diameter ball-retainer assembly, which is a first form of rolling wave generator.

5. The electromechanically fused parallel composite flexspline axial harmonic gear speed reducer of claim 1 wherein, When the speed reducer is built-in with an outer rotor motor, the moving part is composed of a composite flexible disc integrated with a ring-shaped deformation rigidity coupling piece on the outer circular side, a rolling wave generator composed of two groups of unequal-diameter balls of the same structure size but with axial concave-convex amounts perpendicular to each other in the circumferential direction and driven in revolution by the retainer, and a flexible thrust bearing high-speed dynamic ring supported by an intermediate angular contact ball bearing; the two rigid end covers fixed with plane straight bevel gears constitute the static part and are fixed on the inner stator of the motor; the ball diameter and circumferential position of each group of unequal-diameter balls must be designed according to the bending deformation surface of the composite flexible disc, and the circumferential spacing of each ball can be unequal, including the unequal-diameter balls that support the two bending deformation surfaces in the orthogonal direction by misalignment; the moving part of the speed reducer and the outer rotor of the motor are radially supported on the two end covers by a pair of deep groove ball bearings with sealing rings, which also separate the motor compartment from the speed reducer compartment; because the elastic deformation forces on the two axial harmonic transmission assemblies that share the composite flexible disc and work in parallel cancel each other out in the moving part, there is no axial force on the deep groove ball bearings; the integrated ring-shaped deformation rigidity coupling piece on the outer circular side of the composite flexible disc superimposes the two amplified low-speed rotating torques and outputs them to the rotating shell through bolts, and the radial and axial external forces on the shell are borne by a pair of angular contact ball bearings between the shell and the fixed end cover.

6. The electromechanically fused parallel compound flexspline axial harmonic reducer of claim 1 or 4 or 5, wherein, The flexible thrust bearing integrated on both sides of the composite flexible disc is driven by the two unequal diameter ball groups on both sides of the low-speed dynamic ring raceway. The circumferential relative position between the balls of each unequal diameter ball group is fixed at all times. The two unequal diameter balls on both sides of the four curved deformation surfaces on the composite flexible disc can form multiple sets of three-point support rolling and rolling deformation states. The deformation amount at each three-point support remains constant, and the deformation amount of each curved deformation surface can be controlled to rotate sequentially in the circumferential direction, from zero to small, then to large, and then back to small and zero, and then repeat. Since the cage has no axial bending, and the axial force or axial displacement between the cage and each ball is independent of the axial concave-convex amount of the rolling wave generator (i.e., the size change of each ball diameter), solid oil can be used for lubrication to avoid the high-speed centrifugal motion of the balls and increase the ability to resist abrasive contamination. The controllable periodic axial wave is generated by the unequal diameter ball groups driven by the cage, but the axial force on all balls must be borne by the high-speed dynamic ring of the flexible thrust bearing supported by the intermediate angular contact ball bearing, which is the second form of rolling wave generator.

7. The electromechanically fused parallel composite flexspline axial harmonic gear speed reducer of claim 1 wherein, When the reducer is built-in outer rotor motor, its moving parts are composed of the composite flexible disc integrated with the tooth profile variable stiffness coupling on the outer circular side, and the second form of rolling wave generator composed of two unequal diameter ball or spherical roller groups with the same structure size but the axial concave-convex amount perpendicular to each other in the circumferential direction and driven by the cage, which are fixed on both ends of the motor outer rotor. The two rigid end covers fixed with the plane straight bevel gears constitute the static part and are fixed on the inner stator of the motor. The ball diameter or spherical curvature of each unequal diameter ball or spherical roller group and the circumferential position must be designed according to the curved deformation surface of the composite flexible disc. The circumferential spacing of each ball or spherical roller can be unequal, but only the unequal diameter ball or spherical roller that can generate two curved deformation surfaces by pressing in the direction can be used. The moving parts of the reducer and the motor outer rotor are radially supported on the two end covers by a pair of deep groove ball bearings with sealing rings, which also separate the motor compartment from the reducer compartment. Because the elastic deformation forces on the two axial harmonic drive assemblies that share the composite flexible disc and work in parallel cancel each other out in the moving parts, there is no axial force on the deep groove ball bearing. The inner circular side of the composite flexible disc is mounted on the intermediate deep groove ball bearing through screws for axial positioning and differential rotation between the motor outer rotor. The resultant force of all axial forces acting on this bearing is zero. The integrated tooth profile variable stiffness coupling on the outer circular side will superimpose two routes of amplified low-speed rotating torque, which is output to the rotating shell through the meshing of the inner ring with the same number of teeth as the tooth profile coupling in the rotating shell. The radial and axial external forces on the shell are borne by a pair of angular contact ball bearings between the shell and the fixed end cover. The arc-shaped spur gears on the outer circular side of the composite flexible disc for outputting low-speed rotating torque and the plane spur gears on both sides of the composite flexible disc can have the same tooth profile, or different tooth profiles and different tooth numbers. The former is beneficial to machining, installation, and two-by-two orthogonal bending deformation, while the latter increases the machining difficulty but can increase the meshing area, reduce friction and wear during the swinging process of the composite flexible disc, and improve the transmission accuracy from the toothless meshing angle (such as the spline form meshing).

8. The electromechanically fused parallel compound flexspline axial harmonic gear speed reducer of claim 1 or 4 or 6 or 7, wherein, The flexible thrust bearing low-speed dynamic raceway integrated on both sides of the composite flexible disc is parallel to the surface of the composite flexible disc, and the material of the flexible thrust bearing low-speed dynamic raceway is less than that in claims 2, 3 and 5, so that the elastic deformation energy consumption generated during operation is less, and the relative positions of the two unequal diameter balls or spherical rollers of each unequal diameter ball or spherical roller group driven by the cage are fixed; the four bending deformation surfaces on the composite flexible disc are only rolled out of the bending deformation state by the unequal diameter ball or spherical roller group in the corresponding direction; the deformation amount at the contact between each ball or spherical roller and the composite flexible disc is always constant, thereby controlling the sequential rotation of each bending deformation surface in the circumferential direction, and the deformation amount changes from zero to small to large, then back to small and back to zero, and the cycle is repeated; therefore, solid oil scheme can still be used for lubrication to avoid the high-speed centrifugal motion of the ball or spherical roller throwing off the lubricating grease, and to increase the ability to resist abrasive contamination; the controllable periodic axial wave is generated by the unequal diameter ball or spherical roller group driven by the cage, but the axial force on all balls or spherical rollers must be borne by the flexible thrust bearing high-speed raceway supported by the intermediate angular contact ball bearing, and the radial force of the spherical roller is borne by the stop edge of the flexible thrust bearing high-speed raceway.

9. The electromechanically fused parallel composite flexspline axial harmonic gear speed reducer of any one of claims 1-8, wherein, Due to the characteristics that the radial section of the composite flexible disc will periodically swing left and right nearly twice per revolution of the rolling wave generator during low-speed rotation, the planar straight gear fixed on the rigid end cover is designed as an umbrella-shaped planar straight gear parallel to the planar straight gear tooth length generatrix on the maximum bending deformation outer surface of the composite flexible disc to improve the meshing area; since the number of teeth of the planar straight gear on the composite flexible disc is slightly more than the number of teeth of the straight umbrella gear on the two rigid end covers, in the case that the former only generates four bending deformation surfaces that are symmetrically deformed in pairs, if the difference in the number of teeth between the two is an odd multiple of 2, the two straight umbrella gears of the latter need to be installed with a circumferential displacement of half a tooth to work correctly; but if the difference in the number of teeth is an even multiple of 2, the latter does not need to be installed with a circumferential displacement; and the radial section of the four intersection lines between the four bending deformation surfaces of the former is the original undeformed radial section state, and the integrated variable stiffness connecting piece thereon is either a ring piece or a tooth shape, which has low axial swing stiffness and high circumferential torsional stiffness; if the composite flexible disc is forced to generate an even number of bending deformation surfaces greater than 4, although the axial concave-convex amount of the rolling wave generator may not be circumferentially orthogonal, as long as the adjacent bending deformation surfaces are axially symmetrically deformed after rotating an angle of 360° / the number of even bending deformation surfaces, they can work according to the principle of the electromechanically fused parallel composite flexible disc type axial harmonic reducer.

10. The electromechanically fused parallel composite flexspline axial harmonic gear speed reducer of any one of claims 1-9, wherein, For the motor with short rotor and large air gap, the two rolling wave generators in the moving part have the same structure size but the axial concave-convex amount is perpendicular to each other in the circumferential direction. Therefore, the two ball-retainer assemblies with the same structure on both sides of the composite flexible disc are supported or suspended in the two rigid straight bevel gears by the gear teeth on the four curved and deformed outer surfaces of the composite flexible disc which are symmetrically deformed in pairs. The axial displacement of the ball-retainer assembly is constrained by the symmetric deformation of the composite flexible disc, the straight bevel gear meshing between the two rigid straight bevel gears and the axial symmetric composite flexible disc, and the rigid rotating shell or mandrel supported by the angular contact ball bearing can assist in constraining the radial and axial displacement of the moving part and the motor rotor through the integrated variable stiffness coupling via the composite flexible disc. Therefore, the motor does not need to use a pair of deep groove ball bearings to support the stator and rotor, thereby reducing the number of bearings required, simplifying the support structure of the reducer, and reducing unnecessary friction loss and temperature rise. The separation of the motor compartment and the reducer compartment can be solved by the sealing ring between the moving part and the end cover. Thus, the high-speed motor power input is integrated into the reducer with a large reduction ratio output, and only one pair of generalized composite flexible thrust bearings and one pair of angular contact ball bearings can complete the deformation and reduction, support the moving part and the motor rotor, share different properties of internal and external loads, and work at high and low speeds, respectively. The support of each moving component is clear and cooperative.

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