Parallel telescopic flexible gear type follow-up loading mechanism

Abstract

The flexible bearing dynamic performance testing device is a parallel telescopic flexible gear type follow-up loading mechanism. Two hat-shaped flexible gears are screwed or two clamping flexible gears are clamped on the two sides of a split cambered surface knife edge hoop connecting piece outside the constant circle middle section cylinder wall of the orthogonal antisymmetric deformation thin-wall flexible cylinder in a back-to-back parallel connection mode, and the thick wall ends of the flexible gears are arranged on the outer circles of the two ends of the thin-wall flexible cylinder in a sleeving mode respectively. Non-circular follow-up radial elastic deformation force generated when the flexible gear works is used for simulating distributed follow-up radial loads applied to the two long shaft ends of the tested flexible bearing due to small tooth difference meshing transmission of rigid gear teeth and flexible gear teeth in a harmonic reducer. The size of the applied follow-up radial load is changed by increasing or decreasing the wall thickness of the thick-wall end or overlapping different layers of clamping type flexible gears, and the axial displacement and the circumferential displacement of each flexible gear are restrained by the hat edge or the clamping button end of the flexible gear; interlayer friction heat of the tested flexible bearing, the thin-wall flexible cylinder and each nested flexible gear can be reduced through the flexible gear thin-wall section with multiple holes in a strong wind cooling or micro-droplet evaporation mode.

Description

Technical Field

[0001] The utility model patent relates to the technical field of rolling bearing performance detection, and particularly relates to a test device for applying a load to two flexible bearings by using a follow-up orthogonal antisymmetric elastic deformation force of a thin-walled flexible cylinder for dynamic performance testing. The follow-up orthogonal antisymmetric elastic deformation force of the thin-walled flexible cylinder is used to simulate the flexspline in a harmonic reducer, and the actual or increased distributed follow-up radial load condition applied to the long shaft ends of the two tested flexible bearings due to the meshing transmission with a small tooth difference between the rigid spline teeth and the flexspline teeth. Background Art

[0002] The harmonic reducer is a core component in precision machine tool transmission devices, industrial robotic arms, and joint modules for embodied intelligent machinery. Its dynamic performance such as service life, accuracy, and frictional torque has an important impact on the performance of these devices. Compared with transmission methods such as gears, chains, and belts, harmonic drive has the characteristics of a large transmission ratio, simple structure, coaxial transmission, small volume, and high accuracy. The low-speed moving ring and the flexspline of the flexible bearing are the two flexible components of the harmonic reducer and are also the main components determining the service life, transmission efficiency, and transmission strength of the harmonic reducer. Compared with ordinary rolling bearings, the wall thickness of the inner and outer rings of the flexible bearing used in the harmonic reducer is thinner. After being installed on the wave generator, it is forced to change from a circular shape to a non-circular shape. In the working state, the loaded area of the flexible bearing will synchronously change with the rotation of the long shaft position of the wave generator, belonging to a follow-up loaded condition. The low-speed moving ring of the flexible bearing is also subjected to the non-circular preloading force of the wave generator, the elastic deformation force of the flexspline, and the meshing force between the rigid spline teeth and the flexspline teeth during operation, generating alternating radial normal stress, radial bending, and axial torsional stress. Therefore, in addition to failures such as wear and pitting, the flexible bearing will also experience bending and torsional fatigue failures.

[0003] With the popularization of intelligent manufacturing technology, the application conditions for embodied intelligent machinery and industrial robotic arms are becoming increasingly demanding, and the failure problem of flexible bearings used in harmonic reducers is becoming increasingly prominent. Currently, domestic and foreign research on flexible bearings used in harmonic reducers mainly focuses on theoretical analysis and functional applications, and the understanding of their failure modes and mechanisms is not sufficient. At present, the performance evaluation of flexible bearings is mainly based on the overall machine test of the harmonic reducer. However, in the overall machine test, in addition to the failure of the flexible bearing, there are also failures of other components such as the flexspline and gears, and there are many uncontrollable factors due to different test conditions, which will interfere with the failure analysis and evaluation of the flexible bearing. Due to the unique follow-up loaded method of the flexible bearing used in the harmonic reducer, there are very few flexible bearing dynamic performance test devices that can truly simulate the follow-up loading method of the harmonic reducer, and the corresponding evaluation methods are not unified, seriously restricting the development of flexible bearing dynamic performance evaluation technology.

[0004] The invention patent application "Dynamic Performance Testing Device for Double Flexible Bearings Based on Follow-up Orthogonal Anti-Symmetric Deformation Loading of Flexible Cylinders" (Publication No.: CN 117330313 A) and the utility model patent "Dynamic Performance Testing Device for Flexible Bearings with Parallel Flexible Cylinder Deformation Follow-up Loading" (Patent No.: ZL 2024 2 0397762.9) utilize the follow-up orthogonal anti-symmetric deformation method of thin-walled flexible cylinders to apply follow-up loads of equal magnitude and perpendicular directions to the two flexible bearings to be tested. By using wave generators and flexible cylinders with different structural dimensions, the magnitude of the load applied to the flexible bearings is changed, realizing a new type of loading and dynamic performance measurement method for flexible bearings used in harmonic reducers with simple structure and adjustable load. However, in this loading mechanism, the inner holes at both ends of the flexible cylinder and the two flexible bearings to be tested are axially and circumferentially constrained through transitional fits. During long-term life tests, multi-directional wear will occur due to inconsistent deformation of the mating surfaces, resulting in loosening, causing the axial position of the flexible cylinder to change and circumferential rotation, resulting in a gradual decrease in the applied test load and an increase in the temperature of the test section. Moreover, since the thin-walled flexible cylinder is in a high-frequency orthogonal anti-symmetric radial elastic deformation state during operation, if the wall thickness of the flexible cylinder is increased to change the magnitude of the applied load, the wall openings at both ends of the flexible cylinder with a slightly thicker wall are prone to cracking, and the flexible cylinder generates serious heat, making it difficult to conduct accelerated heavy-load tests. Utility Model Content

[0005] In view of the problems existing in the follow-up loading technology in the simulation test of flexible bearings for harmonic reducers, based on the utility model patent ZL 2024 2 0397762.9, this utility model patent provides two parallel nested flexible gear type follow-up loading mechanisms. The parallel nested flexible gear type follow-up loading mechanism consists of a thin-walled flexible cylinder with non-equal diameter inner and outer holes, an integral and split circular arc surface knife-edge hoop connector on the inner and outer sides of the constant circular cross-section cylinder wall of the thin-walled flexible cylinder, two top hat type flexible gears screwed back-to-back or two clamped type flexible gears clamped on the two sides of the split circular arc surface knife-edge hoop connector, different layers of clamped type flexible gears sleeved on the top hat type flexible gears or clamped type flexible gears, and an improved circular arc bracket. Among them, the integral and split circular arc surface knife-edge hoop connector is a radial hoop-shaped connector with inner and outer diameters being circular arc surfaces, and the knife-edge is supported on the inner and outer sides of the constant circular cross-section cylinder wall of the thin-walled flexible cylinder.

[0006] In each pair of tested flexible bearings, wave generators with the same structure and orthogonal major axes are nested in the inner holes, and then pressed into the inner holes at both ends of a thin-walled flexible cylinder whose inner diameter in the middle is slightly smaller than the outer diameter of the tested flexible bearings at both ends, causing the thin-walled flexible cylinder to produce orthogonal antisymmetric deformation. The middle hole diameter can jointly constrain the axial displacement of the two tested flexible bearings and the thin-walled flexible cylinder due to the multi-directional frictional forces generated by the inconsistent deformation between the mating surfaces with the side retaining edges on the non-circular outer diameter of the two wave generators. The follow-up orthogonal antisymmetric elastic deformation force of the thin-walled flexible cylinder can be used to simulate the entire flexible gear in the harmonic reducer, as well as a part of the distributed follow-up radial load conditions applied to the long-axis ends of the two tested flexible bearings due to the meshing transmission with a small tooth difference between the rigid gear teeth and the flexible gear teeth.

[0007] The inner circles of the thick-walled ends of two top-hat-shaped flexible gears or cassette-shaped flexible gears in back-to-back parallel connection are respectively sleeved on the outer circles at both ends of the thin-walled flexible cylinder. The non-circular follow-up radial elastic deformation force generated by the flexible gear due to the rotation of the non-circular inner ring of the tested flexible bearing is used to simulate the remaining part and the increased distributed follow-up radial load applied to the two long-axis ends of the tested flexible bearing due to the meshing transmission with a small tooth difference between the rigid gear teeth and the flexible gear teeth in the harmonic reducer.

[0008] By increasing or decreasing the wall thickness of the thick-walled end of the top-hat-shaped flexible gear or cassette-shaped flexible gear, or by sleeving different numbers of layers of cassette-shaped flexible gears, the magnitude of the applied follow-up radial load can be changed; the radial deformation force of each flexible gear can also play a role in constraining the increase in the deformation gap between the thin-walled flexible cylinder and the tested flexible bearing due to the inconsistent deformation between the mating surfaces, reducing the multi-directional relative friction between the two; the axial and circumferential forces of each flexible gear are constrained by different forms of snap rings and pins at the top-hat edges or cassette buttons fixedly connected to them.

[0009] The frictional heat between the layers of the tested flexible bearing, the thin-walled flexible cylinder, and each sleeved flexible gear can be reduced by strong air cooling or micro-droplet evaporation through the thin-walled section of the flexible gear with numerous small holes. Description of the Drawings

[0010] Figure 1 It is a schematic diagram of the assembly relationship between the flexible bearing and the flexible cylinder in Patent ZL 2024 2 0397762.9;

[0011] Figure 2 It is a schematic diagram of the parallel sleeved flexible gear type follow-up loading mechanism of the screwed top-hat-shaped flexible gear;

[0012] Figure 3 It is a schematic diagram of the fixing method and structure of the connecting screw with the thin-walled flexible cylinder and the integral and split circular arc surface knife-edge hoop connectors inside and outside the constant circular middle section cylinder wall;

[0013] Figure 4 It is a schematic diagram of the structure of the top-hat-shaped flexible gear, the pin, the inclined wedge snap ring, and the cassette-shaped flexible gear with an inclined wedge cassette button;

[0014] Figure 5It is a schematic diagram of a parallel nested flexible gear type follow-up loading mechanism of a cartridge-mounted flexible gear;

[0015] Figure 6 It is a schematic diagram of the structure of a cartridge-mounted flexible gear with two straight-wall snap rings, pins and straight-wall snap buttons; Detailed implementation mode

[0016] In order to make the technical problems, technical solutions and beneficial effects to be solved by the utility model more clear and understandable, the present invention 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 invention and are not used to limit the present invention.

[0017] In the following description, specific details such as specific internal programs and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present utility model. However, those skilled in the art should clearly understand that the present invention can also be implemented in other embodiments without these specific details. In other cases, the detailed descriptions of well-known systems, devices, circuits and methods are omitted to avoid unnecessary details from interfering with the description of the present utility model.

[0018] Figure 1 It is a schematic diagram of the assembly relationship between the flexible bearing and the flexible cylinder in the utility model patent ZL 2024 2 0397762.9. Each pair of flexible bearings 6 is nested with a wave generator 7 with the same structure and the major axes perpendicular to each other, and then pressed into the inner holes at both ends of the flexible cylinder 5 with the same diameter. The axial distance between the two wave generators 7 can be changed by the length of the positioning sleeve 14; when the wave generator 7 installed on the motor shaft 3 of the motor 2 rotates, the orthogonal antisymmetric deformation of the flexible cylinder 5 is used to apply a follow-up load with the same magnitude and orthogonal directions to each pair of flexible bearings 6. The vibration performance of the flexible bearings 6 is transmitted to the vibration sensor 11 thereon through the connecting screw 10 installed at the mid-section of the flexible cylinder by the semi-cylindrical bracket 4. The present utility model patent is Figure 1 Based on this, improvements are made, and two parallel nested flexible gear type follow-up loading mechanisms are provided to solve the existing problems and expand its loading capacity.

[0019] Embodiment 1

[0020] As Figure 2 shown, this embodiment provides a schematic diagram of a parallel nested flexible gear type follow-up loading mechanism of a screw-mounted top hat type flexible gear in the present utility model patent. For the convenience of display, all Figure 1The parts that remain unchanged except for the vibration sensor 11 are outlined with double-dashed lines and uniformly represented by the number 40. The inner diameter of the middle part of the thin-walled flexible cylinder 30 in the servo loading mechanism is slightly smaller than the aperture diameter of the holes for installing the flexible bearings to be tested at both ends. The thin-walled flexible cylinder 30 is fixedly connected with the integral circular arc surface knife-edge hoop connector 32 inside the constant circular middle-section cylinder wall and the split circular arc surface knife-edge hoop connector 22 outside the middle-section cylinder wall by screws 31. The lower part of the latter is fixed to the circular arc bracket 21 fixedly connected to the motor end cover by screws 20 through screws 23, while the upper part of the latter is connected to the vibration sensor 11 via screws 34. On the two sides of the split circular arc surface knife-edge hoop connector 22, two top-hat-shaped flexible gears 24 and four inclined wedge snap rings 25 and 26 with two groups of different inner hole diameters and inclined wedge-shaped ring inner holes are screwed in parallel back-to-back with bolts 27. The snap-type flexible gears 29 and 28 of four inclined wedges with two groups of different diameters and triangular inclined ring surfaces at the thin-walled ports are respectively embedded into the corresponding inclined wedge snap rings 25 and 26. The axial and circumferential forces of the two top-hat-shaped flexible gears 24 are constrained by the top-hat edges fixedly connected to them, and the axial and circumferential displacements of the snap-type flexible gears 29 and 28 of each inclined wedge button are constrained by the inclined wedge snap rings at their button ends and the pin 33.

[0021] Figure 3 Figure 4 shows an enlarged schematic cross-sectional structure of fixedly connecting the thin-walled flexible cylinder 30 with the integral circular arc surface knife-edge hoop connector 32 inside the constant circular middle-section cylinder wall and the split circular arc surface knife-edge hoop connector 22 outside the middle-section cylinder wall by screws 31. Neither of the two circular arc surface knife-edge hoop connectors 22 and 32 will limit the micro-swing generated at the middle section of the thin-walled flexible cylinder 30 due to the high-frequency orthogonal anti-symmetric radial elastic deformation during operation because of the circumferential knife-edge structure of the circular arc surfaces in contact with the wall surface of the thin-walled flexible cylinder 30.

[0022] Figure 4 Figure 8 shows an enlarged schematic cross-sectional structure of the top-hat-shaped flexible gear 24, the pin 33, the inclined wedge snap ring 25, and the snap-type flexible gear 29 of the inclined wedge button, showing the mutual structural relationship among the four. Among them, the axial and circumferential forces of the top-hat-shaped flexible gear 24 are borne by the latter that is fixed because it is an integral structure with the top-hat edge; while the axial force of the snap-type flexible gear 29 is constrained by its inclined wedge button and the inclined wedge snap ring 25, and its circumferential displacement is constrained by the pin 33 on the top-hat-shaped flexible gear 24. Figure 4 Numerous small holes are designed and made in the thin-walled sections in the middle of the top-hat-shaped flexible gear 24 and the snap-type flexible gear 29 of the inclined wedge button in [document name] for reducing the interlayer frictional heat and radial elastic deformation heat of the flexible bearings to be tested, the thin-walled flexible cylinder, and each nested flexible gear by means of forced air cooling or micro-droplet evaporation.

[0023] Embodiment 2

[0024] As Figure 5As shown, this embodiment provides a schematic diagram of a parallel nested flexible gear type follower loading mechanism of a cartridge flexible gear in the utility model patent. Similar to Embodiment 1, for the convenience of display, all components that remain unchanged except for the vibration sensor 11 are outlined with double-dashed lines and uniformly represented by the number 40, and the structural parts identical to those in Embodiment 1 will not be described again. On the two sides of the split circular arc surface knife-edge hoop connector 22, six three groups of straight-wall snap rings 50, 51, and 52 with different inner hole diameters and right-angle wall-shaped rings in the inner holes are clamped in parallel back-to-back with bolts 27. Three cartridge flexible gears 55, 54, and 53 of straight-wall buttons with different diameters and right-angle hook ring surfaces at the thin-walled ports are respectively inserted into the corresponding straight-wall snap rings 50, 51, and 52. The axial and circumferential forces of the cartridge flexible gears 55, 54, and 53 of each straight-wall button are constrained by the straight-wall snap rings 50, 51, and 52 at their button ends and the pins 33. Figure 1 Among them, the components that remain unchanged except for the vibration sensor 11 are outlined with double-dashed lines and uniformly represented by the number 40, and the structural parts identical to those in Embodiment 1 will not be described again. On the two sides of the split circular arc surface knife-edge hoop connector 22, six three groups of straight-wall snap rings 50, 51, and 52 with different inner hole diameters and right-angle wall-shaped rings in the inner holes are clamped in parallel back-to-back with bolts 27. Three cartridge flexible gears 55, 54, and 53 of straight-wall buttons with different diameters and right-angle hook ring surfaces at the thin-walled ports are respectively inserted into the corresponding straight-wall snap rings 50, 51, and 52. The axial and circumferential forces of the cartridge flexible gears 55, 54, and 53 of each straight-wall button are constrained by the straight-wall snap rings 50, 51, and 52 at their button ends and the pins 33.

[0025] Figure 6 Figure 6 shows enlarged schematic cross-sectional structures of two straight-wall snap rings 52 and 50, a pin 33, and cartridge flexible gears 53 and 55 of straight-wall buttons with two different diameters, showing the mutual structural relationship among the five. The axial forces of the two cartridge flexible gears 53 and 55 are constrained by their straight-wall buttons and the straight-wall snap rings 52 and 50, and their circumferential forces are constrained by the two pins 33 on the straight-wall snap ring 50. Figure 6 In the cartridge flexible gears 53 and 55 of straight-wall buttons with two different diameters in [Figure 6], numerous small holes are also designed and made in the thin-walled sections in the middle, which can be used to reduce the frictional heat between layers and the radial elastic deformation heat of the tested flexible bearings, thin-walled flexible cylinders, and each nested flexible gear by means of strong air cooling or micro-droplet evaporation.

[0026] The preferred specific embodiments of the utility model have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field based on the concept of the present utility model through logical analysis, reasoning, or limited experiments on the basis of the existing technology should fall within the protection scope determined by the claims.

Claims

1. The parallel nested flexspline type follow-up loading mechanism is characterized in that The described follow-up loading mechanism is for a flexible bearing dynamic performance test device, and is composed of a thin-walled flexible cylinder with non-equal-diameter inner and outer holes in the test device, an integral and split circular arc surface edge hoop connector on the inner and outer sides of the constant circular middle cross-section cylinder wall of the thin-walled flexible cylinder, two top hat-shaped flexible gears screwed in parallel back-to-back on the two sides of the split circular arc surface edge hoop connector or two cartridge-type flexible gears clamped, different layers of cartridge-type flexible gears sleeved on the top hat-shaped flexible gears or the clamped cartridge-type flexible gears, and an improved circular arc bracket.

2. The parallel nested flexspline type follower loading mechanism according to claim 1, wherein The inner diameter in the middle of the thin-walled flexible cylinder is slightly smaller than the installation hole diameters of the outer rings of the two tested flexible bearings at both ends, so that the axial displacement generated by the multi-directional frictional force between the two tested flexible bearings and the thin-walled flexible cylinder due to the mating surface can be jointly constrained by the side flanges on the non-circular outer diameters of two wave generators with the same structure and orthogonal long axes; the follow-up orthogonal anti-symmetric elastic deformation force of the thin-walled flexible cylinder can be used to simulate all of the flexible gear in a harmonic reducer, as well as a part of the distributed follow-up radial load condition applied to the long axis ends of the two tested flexible bearings due to the meshing transmission with a small tooth difference between the rigid gear teeth and the flexible gear teeth.

3. The parallel nested flexible gear type follow-up loading mechanism according to claim 1, characterized in that, The inner circles of the thick-walled ends of the two top hat-shaped flexible gears or cartridge-type flexible gears in parallel back-to-back are respectively sleeved on the outer circles at both ends of the thin-walled flexible cylinder, and the non-circular follow-up radial elastic deformation force generated by the flexible gears due to the rotation of the non-circular inner rings of the tested flexible bearings is used to simulate the remaining part and the increased distributed follow-up radial load applied to the two long axis ends of the tested flexible bearings due to the meshing transmission with a small tooth difference between the rigid gear teeth and the flexible gear teeth in a harmonic reducer.

4. The parallel nested flexspline type follow-up loading mechanism according to claim 3, characterized in that, The magnitude of the applied follow-up radial load can be changed by increasing or decreasing the wall thickness of the thick-walled ends of the top hat-shaped flexible gears or cartridge-type flexible gears or by sleeving different layers of cartridge-type flexible gears. The radial deformation forces of each flexible gear can also restrain the increase in the interlayer deformation gap between the thin-walled flexible cylinder and the tested flexible bearing. The axial and circumferential forces of each flexible gear are constrained by different snap ring forms and pins at the hat brim or button end fixedly connected to it.

5. The parallel nested flexible gear type follow-up loading mechanism according to any one of claims 1, 3 or 4, characterized in that Numerous small holes are provided in the thin-walled sections of each layer of flexible gears, and forced air cooling or micro-droplet evaporation heat dissipation methods are used to reduce the interlayer frictional heat of the tested flexible bearings, the thin-walled flexible cylinder, and each sleeved flexible gear through the numerous small holes.

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