Wave generator and harmonic reducer

Abstract

The application provides a wave generator and a harmonic reducer, and relates to the technical field of harmonic transmission. The wave generator comprises a cam body, a damping ring and a flexible bearing. The damping ring is sleeved outside the cam body, the damping ring and the cam body are in interference fit, and the damping ring is made of damping material. The flexible bearing is sleeved outside the damping ring, and the flexible bearing and the damping ring are in transition fit. The natural frequency of the damping ring is configured as 0.6-0.8 times of the main excitation frequency when the wave generator works. In this way, the damping ring is arranged on the key path of vibration energy transmission from the cam body to the flexible bearing. The damping ring can convert part of the vibration mechanical energy in the transmission process into heat energy and dissipate the heat energy through elastic deformation and internal friction, so that the problem of how to ensure the original structure form, transmission reliability and structural strength of the harmonic reducer and provide a vibration suppression scheme of the harmonic reducer is solved.

Description

Technical Field

[0001] This application relates to the field of harmonic drive technology, specifically to a wave generator and a harmonic reducer. Background Technology

[0002] Regarding the structure of harmonic reducers, the wave generator, as the core component driving the deformation of the flexural wheel, directly affects the transmission accuracy, noise level, and service life of the entire reduction device. Effectively suppressing the vibration and noise generated by the wave generator during high-speed operation has always been a technical goal pursued in this field.

[0003] In related technologies, to achieve the above goals, common strategies include adding independent vibration damping devices to the outside of the harmonic reducer, or attempting to improve its dynamic characteristics by adjusting the structural parameters of the wave generator itself. These methods rely on indirectly influencing vibration behavior by applying damping from outside the system or changing the structural stiffness. However, all of the above solutions have some limitations. Adding external components increases the overall size and complexity of the structure, affecting the adaptability of the harmonic reducer in application scenarios, while simply adjusting structural parameters often makes it difficult to balance vibration reduction effect with transmission performance and structural strength.

[0004] Therefore, how to provide a solution for suppressing vibration of harmonic reducers while ensuring the original structural form, transmission performance and structural strength of the harmonic reducer has become one of the directions explored by those skilled in the art. Summary of the Invention

[0005] In view of this, this application provides a wave generator and a harmonic reducer to solve the problem in the prior art of how to ensure the original structural form, transmission reliability and structural strength of the harmonic reducer while providing a vibration suppression scheme for the harmonic reducer.

[0006] To achieve the above objectives, this application provides the following technical solution: A wave generator, used in a harmonic reducer, includes: Cam body; A damping ring is sleeved on the outside of the cam body. The damping ring and the cam body are interference-fitted, and the damping ring is made of damping material. A flexible bearing is sleeved on the outside of the damping ring, and the flexible bearing and the damping ring are in a transition fit. The natural frequency of the damping ring is configured to be 0.6 to 0.8 times the main excitation frequency when the wave generator is working.

[0007] Optionally, the damping ring reduces the vibration amplitude of the wave generator at the main excitation frequency of 20Hz to 200Hz through the resonance effect.

[0008] Optionally, the damping material is a metal-based composite material or a polymer material.

[0009] Optionally, the damping material is a metal-based composite material, which is an aluminum-based composite material or a titanium-based composite material.

[0010] Optionally, the damping material is a polymer material, which is a polyurethane material or an epoxy resin-based material.

[0011] Optionally, the radial thickness of the damping ring is t, and the inner diameter of the flexible bearing is d, where 0.01×d≤t≤0.05×d.

[0012] Optionally, the interference between the damping ring and the cam body is 0.003 mm to 0.008 mm.

[0013] Optionally, the fit tolerance between the flexible bearing and the damping ring is H7 / g6; or, The flexible bearing and the damping ring are in a clearance fit with a clearance of less than or equal to 0.005 mm.

[0014] Optionally, the coaxiality error of the cam body, the damping ring, and the flexible bearing is less than or equal to 0.005 mm.

[0015] A harmonic reducer includes a rigid wheel, a flexible wheel, and a wave generator as described above.

[0016] The wave generator provided in this application is applied to a harmonic reducer. The wave generator includes a cam body, a damping ring, and a flexible bearing. The damping ring is sleeved on the outside of the cam body, and the damping ring and the cam body are interference-fitted. The damping ring is made of damping material. The flexible bearing is sleeved on the outside of the damping ring, and the flexible bearing and the damping ring are transition-fitted. The natural frequency of the damping ring is configured to be 0.6 to 0.8 times the main excitation frequency when the wave generator is working. This design addresses the problem of excessive vibration and noise caused by the lack of an effective built-in energy dissipation mechanism in the vibration energy transmission path of the wave generator in the harmonic reducer. The wave generator provided in this application addresses this issue by placing a damping ring made of damping material on the outside of the cam body and fitting a flexible bearing around the outside of the damping ring. This places the damping ring on the critical path of vibration energy transmission from the cam body to the flexible bearing. Through its elastic deformation and internal friction, the damping ring converts some of the vibration mechanical energy during transmission into heat energy and dissipates it, effectively attenuating the vibration energy ultimately transmitted to the flexible bearing. This application intervenes at the source of the vibration transmission path, significantly reducing the vibration amplitude of the wave generator during operation, effectively suppressing the resulting noise, and improving the overall operational stability and reliability of the harmonic reducer. Simultaneously, it preserves the original structural form of the wave generator without sacrificing structural compactness, transmission performance, or structural strength. This solves the problem in existing technologies of how to provide a vibration suppression solution for harmonic reducers while maintaining their original structural form, transmission reliability, and structural strength. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the wave generator provided in an embodiment of this application.

[0019] exist Figure 1 middle: 10. Wave generator; 101. Cam body; 102. Damping ring; 103. Flexible bearing. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] As we know, in the structure of a harmonic reducer, to drive the flex wheel to generate controllable elastic deformation for speed reduction, its basic working principle is that the motor drives the cam to rotate. The non-circular contour of the cam, through the inner ring of the tightly fitted flexible bearing, forces the outer ring and the flex wheel pressed against it to undergo periodic waveform deformation, thereby meshing with the rigid wheel for transmission. However, the applicant has found that in scenarios with stringent requirements for transmission smoothness and noise control, such as high-precision industrial robot joints or precision optical equipment, its performance is not ideal. This is because, in order to optimize its motion transmission efficiency and structural compactness, its inherent design inevitably compromises its vibration suppression capability. Specifically, the tight fit between the cam and the flexible bearing is used to ensure motion transmission, but the high-frequency vibration energy generated by the cam during high-speed operation is directly transmitted to the flexible bearing and subsequent flex wheel through the rigid contact interface with almost no attenuation, lacking an effective built-in energy dissipation path. This results in high vibration peaks and noise levels in the harmonic reducer during operation, which may lead to component fatigue and affect transmission accuracy and reliability over long-term operation.

[0022] Based on the above considerations, such as Figure 1As shown, this application embodiment provides a wave generator 10, which is applied to a harmonic reducer. The wave generator 10 includes a cam body 101, a damping ring 102, and a flexible bearing 103 coaxially arranged. The damping ring 102 is sleeved on the outside of the cam body 101, and the damping ring 102 and the cam body 101 are interference-fitted. The damping ring 102 is made of damping material. The flexible bearing 103 is sleeved on the outside of the damping ring 102, and the flexible bearing 103 and the damping ring 102 are transition-fitted. The cam body 101 is typically an elliptical or other rigid component with a central inner hole or keyway for connection to the input shaft. The damping ring 102 is an integrally ring-shaped component whose inner hole profile matches the outer profile of the cam body 101. The damping ring 102 is tightly fitted and fixed to the outside of the cam body 101 via an interference fit. This interference fit ensures that the vibration energy of the cam body 101 can be efficiently and with low loss transmitted to the damping ring 102 during high-speed rotation and vibration. The flexible bearing 103 is fitted onto the outside of the damping ring 102. The flexible bearing 103 is a thin-walled special bearing. Its outer ring contacts the inner wall of the flex wheel of the harmonic reducer, while its inner ring mates with the outer cylindrical surface of the damping ring 102. The inner ring of the flexible bearing 103 and the outer cylindrical surface of the damping ring 102 are fitted with a transition fit, ensuring sufficient contact area between the flexible bearing 103 and the damping ring 102 to transmit motion and vibration.

[0023] This configuration addresses the problem of excessive vibration and noise caused by the lack of an effective built-in energy dissipation mechanism in the vibration energy transmission path of the wave generator 10 in the harmonic reducer. The wave generator 10 provided in this application addresses this issue by setting a damping ring 102 made of damping material on the outside of the cam body 101, and placing a flexible bearing 103 around the outside of the damping ring 102. The damping ring 102 acts as a functional intermediate layer, with its inner surface connected to the outer surface of the cam body 101 and its outer surface connected to the inner ring of the flexible bearing 103. This forms a vibration transmission and conversion path of "cam body 101 - damping ring 102 - flexible bearing 103," placing the damping ring 102 at the crucial point of vibration energy transmission from the cam body 101 to the flexible bearing 103. On the key path, the damping ring 102, through its own elastic deformation and internal friction, can convert part of the vibration mechanical energy during transmission into heat energy and dissipate it, thereby effectively attenuating the vibration energy ultimately transmitted to the flexible bearing 103. This application intervenes at the source of the vibration transmission path, significantly reducing the vibration amplitude of the wave generator 10 during operation, effectively suppressing the noise generated, and improving the overall operational stability and reliability of the harmonic reducer. At the same time, it ensures the original structural form of the wave generator 10 without sacrificing structural compactness, transmission performance, and structural strength, solving the problem in the prior art of how to provide a vibration suppression scheme for a harmonic reducer while ensuring the original structural form, transmission reliability, and structural strength of the harmonic reducer.

[0024] Compared to wave generators of the same specifications and models in conventional designs, the combination of cam body 101 and damping ring 102 in this application is roughly equivalent to a cam in a conventional design in terms of outer diameter.

[0025] To further improve the absorption efficiency of the damping ring 102 for vibration energy at specific frequencies, the dynamic characteristics of the damping ring 102 are specifically designed in some preferred embodiments. It is understood that under specific operating conditions (such as rated speed and load), the main excitation frequency components experienced by the wave generator 10 of the harmonic reducer are relatively clear or predictable. These main excitation frequencies may originate from electromagnetic harmonics of the input motor, torsional vibration modes or meshing frequencies of the transmission chain, and their harmonics. The damping ring 102 is designed as a vibration system with a specific natural frequency, which is determined by the elastic modulus and density of the ring material, as well as the ring's geometric dimensions (such as average radius, radial thickness, and axial width). Through material selection and precise dimensional design, the natural frequency of the damping ring 102 is configured to be 0.6 to 0.8 times the main excitation frequency of the wave generator 10 during operation. For example, if the core excitation frequency of a certain type of harmonic reducer wave generator 10 under target operating conditions is determined to be 100 Hz through analysis or testing, the natural frequency of the damping ring 102 can be designed in the range of 60 Hz to 80 Hz.

[0026] According to mechanical vibration theory, when the natural frequency of the damping ring 102 is close to the main frequency of the external excitation system (the vibration of the cam body 101), the system is prone to resonance. In this embodiment, the natural frequency of the damping ring 102 is deliberately tuned to be slightly lower than the main excitation frequency, placing it in the sub-resonance region. When the cam body 101 vibrates at the main excitation frequency, the damping ring 102 will produce a significant forced vibration response at the same frequency. Since its natural frequency is tuned to be close to the excitation frequency, the high damping characteristics of the damping ring 102 material play a key role. Larger strain energy and more intense micro-friction are generated inside the damping ring 102, and the vibration amplitude of the damping ring 102 is amplified. The high damping loss factor of the material allows this amplified mechanical energy to be converted into heat energy and dissipated with extremely high efficiency.

[0027] Furthermore, in some specific embodiments, the damping ring 102 reduces the vibration amplitude of the wave generator 10 at the main excitation frequencies of 20Hz to 200Hz through the resonance effect.

[0028] With this configuration, the main excitation frequency range of the wave generator 10 in this embodiment is typically between 20 Hz and 200 Hz. This frequency band covers the common vibration and noise problems of harmonic reducers in many industrial applications, such as low-frequency vibration under low-speed, high-torque conditions, or mid-frequency vibration generated by meshing during high-speed operation. By configuring the natural frequency of the damping ring 102 to be 0.6 to 0.8 times the corresponding value in this frequency band, the damping ring 102 can significantly reduce the vibration amplitude of the wave generator 10 in the critical frequency band of 20 Hz to 200 Hz through the aforementioned resonance effect. This makes the vibration reduction design more targeted, enabling the priority elimination of frequency components that contribute the most to system performance and noise in the complex vibration spectrum, thereby achieving better vibration reduction and noise reduction effects with a more optimized structure.

[0029] Based on the foregoing embodiments, whether the damping ring 102 can achieve the expected energy dissipation function fundamentally depends on its constituent materials. This application also provides several specific implementation schemes for high-performance damping materials. In some optional embodiments, the damping material is a metal-based composite material, preferably an aluminum-based composite material or a titanium-based composite material. Aluminum-based composite materials have the advantages of low density and high specific stiffness, and can obtain a high damping loss factor while maintaining good mechanical strength and thermal conductivity. Titanium-based composite materials have higher specific strength and excellent corrosion resistance, making them suitable for applications with more stringent strength and environmental requirements.

[0030] In some alternative embodiments, the damping material is a high-molecular polymer, particularly certain special engineering plastics. Due to their long molecular chain structure, the movement of chain segments under stress and deformation generates strong internal friction, thus possessing intrinsic high damping characteristics. Polyurethane or epoxy resin-based materials are preferred. Polyurethane materials have a wide range of elastic moduli, wear resistance, and adjustable damping performance; their microphase separation structure provides an ideal site for energy dissipation. Epoxy resin-based materials can be modified by adding flexible segments, nanofillers, or hollow microspheres to improve damping capacity while maintaining high stiffness.

[0031] Furthermore, this application also describes some preferred parameter ranges and detailed features of the wave generator 10, which can be combined with any of the foregoing embodiments to optimize overall performance, reliability and manufacturability.

[0032] In some specific embodiments, the radial thickness of the damping ring 102 is t, which is also the difference between the inner and outer diameters of the damping ring 102. The inner diameter of the flexible bearing 103 is d, where 0.01×d≤t≤0.05×d.

[0033] In this design, the applicant considered that the radial thickness t of the damping ring 102 is one of its key dimensions, directly affecting its stiffness, natural frequency, and the volume of material involved in energy dissipation. This provides a clear quantitative basis for the design of the damping ring 102. If the radial thickness of the damping ring 102 is too thin, its stiffness may be insufficient and its energy dissipation volume limited; if the radial thickness of the damping ring 102 is too thick, it will excessively affect the dimensions of the cam body 101. Through extensive simulation analysis and experimental verification, the above-mentioned thickness design range was established. This range can maintain the original compactness and functionality of the wave generator 10 to the greatest extent while ensuring sufficient damping performance and structural strength.

[0034] Furthermore, in some specific embodiments, the interference between the damping ring 102 and the cam body 101 is 0.003 mm to 0.008 mm.

[0035] This configuration takes into account that the interference fit between the damping ring 102 and the cam body 101 is the key to achieving efficient transmission of vibration energy. The interference needs to be precisely controlled. Insufficient interference will result in insufficient pressure on the mating surface, which may cause fretting wear or even loosening under alternating loads, affecting vibration transmission efficiency and long-term reliability. Excessive interference will make assembly difficult and generate excessive assembly stress in the damping ring 102 or cam body 101 during assembly or when the operating temperature changes, which may lead to material yielding or cracking. Based on production practice and mechanical model calculations, the preferred interference fit range is 0.003 mm to 0.008 mm. The lower limit of this range (0.003 mm) is determined by the minimum pressure required to ensure that the mating surfaces do not slip relative to each other within the working load and temperature range. The upper limit of this range (0.008 mm) is limited by the yield strength of the damping ring 102 material and / or the cam body 101 material, which aims to avoid plastic deformation during assembly and ensure the reliability of the connection. Within this design range, sufficient and uniform contact pressure is ensured between the damping ring 102 and the cam body 101 to achieve a tight interface bond and efficient vibration energy transfer, ensuring that the damping ring 102 and the cam body 101 are reliably connected to transmit vibration without damaging the parts.

[0036] In some other preferred embodiments, the fit between the inner ring of the flexible bearing 103 and the outer cylindrical surface of the damping ring 102 needs to be balanced between vibration energy transmission efficiency and avoiding bearing jamming. This application provides two preferred fit schemes.

[0037] The first option uses a standard tolerance fit. Specifically, the tolerance zone of the outer cylindrical surface of the damping ring 102 can be selected as g6, and the tolerance zone of the inner hole of the flexible bearing 103 can be selected as H7, forming an H7 / g6 fit. This is a commonly used transition fit with very small clearance or interference. This fit ensures good alignment between the two parts and provides sufficient contact area to transmit vibration, while also having moderate assembly difficulty, facilitating production and maintenance. The second option uses a small clearance fit, explicitly designing a clearance fit between the flexible bearing 103 and the damping ring 102, and controlling the clearance value within 0.005 mm to avoid the impact of assembly stress on the rotational flexibility of the flexible bearing 103. Simultaneously, due to the extremely small clearance, the two parts can still maintain actual contact or near-contact during operation, and vibration energy can still be effectively transmitted from the damping ring 102 to the inner ring of the flexible bearing 103 through a medium (such as a lubricating oil film) or microscopic impacts, achieving vibration reduction.

[0038] With this configuration, both schemes provide precise control over the fit between the damping ring 102 and the inner ring of the flexible bearing 103. This fit design allows for a very small gap or a slight interference tendency between the two, ensuring sufficient contact area to effectively transmit vibration excitation to the damping ring 102, thus not affecting the vibration reduction function. At the same time, it clearly avoids an overly tight fit, fundamentally preventing problems such as expansion of the inner ring of the flexible bearing 103, reduced clearance, or inflexible rotation due to excessive assembly stress, thus protecting the bearing's motion accuracy and service life.

[0039] In some preferred embodiments, the cam body 101, damping ring 102, and flexible bearing 103 are precisely machined and assembled, with the coaxiality error controlled to be less than or equal to 0.005 mm. This high degree of concentricity ensures that vibration energy can be uniformly transmitted from the cam body 101 through the damping ring 102 to the entire circumference of the flexible bearing 103, avoiding local stress concentration, uneven wear, or decreased vibration damping efficiency caused by eccentricity.

[0040] Based on the wave generator 10 described above, this application embodiment also provides a harmonic reducer, which includes a rigid wheel, a flexible wheel, and the wave generator 10 described above. The flexible wheel is fitted inside the rigid wheel, and the flexible wheel and the rigid wheel mesh with each other. The wave generator 10 is fitted inside the flexible wheel. Since this harmonic reducer has the wave generator 10 described above, the beneficial effects brought by the wave generator 10 to the harmonic reducer can be referred to the above content, and will not be repeated here.

[0041] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0042] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0043] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0044] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0045] It should be understood that the qualifiers “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of this application.

[0046] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A wave generator, characterized in that, Applications in harmonic reducers include: Cam body; A damping ring is sleeved on the outside of the cam body. The damping ring and the cam body are interference-fitted, and the damping ring is made of damping material. A flexible bearing is sleeved on the outside of the damping ring, and the flexible bearing and the damping ring are in a transition fit. The natural frequency of the damping ring is configured to be 0.6 to 0.8 times the main excitation frequency when the wave generator is working.

2. The wave generator according to claim 1, characterized in that, The damping ring reduces the vibration amplitude of the wave generator at the main excitation frequencies of 20Hz to 200Hz through the resonance effect.

3. The wave generator according to claim 1 or 2, characterized in that, The damping material is a metal-based composite material or a polymer material.

4. The wave generator according to claim 1 or 2, characterized in that, The damping material is a metal-based composite material, which is either an aluminum-based composite material or a titanium-based composite material.

5. The wave generator according to claim 1 or 2, characterized in that, The damping material is a polymer material, which is either a polyurethane material or an epoxy resin-based material.

6. The wave generator according to claim 1 or 2, characterized in that, The radial thickness of the damping ring is t, and the inner diameter of the flexible bearing is d, where 0.01×d≤t≤0.05×d.

7. The wave generator according to claim 6, characterized in that, The interference between the damping ring and the cam body is 0.003 mm to 0.008 mm.

8. The wave generator according to claim 7, characterized in that, The fit tolerance between the flexible bearing and the damping ring is H7 / g6; or... The flexible bearing and the damping ring are in a clearance fit with a clearance of less than or equal to 0.005 mm.

9. The wave generator according to claim 1, characterized in that, The coaxiality error of the cam body, the damping ring, and the flexible bearing is less than or equal to 0.005 mm.

10. A harmonic reducer, characterized in that, It includes rigid wheels, flexible wheels, and wave generators as described in any one of claims 1-9.

Images