A cage for a harmonic reducer

Abstract

The application discloses a cage for harmonic reducer, which comprises a cage body, the cage body is provided with rectangular wave crests and rectangular wave troughs which are arranged continuously in a circle, first pockets and second pockets for accommodating cylindrical rollers are formed in the rectangular wave crests and the rectangular wave troughs respectively, the first pockets have lower side openings, and the second pockets have upper side openings, vertical peak sections and vertical valley sections of the rectangular wave crests and the rectangular wave troughs form window beams, during periodic oval deformation of the cage, the rectangular wave crests and the rectangular wave troughs can change the wave length through deformation, uniformly disperse stress, reduce stress concentration phenomenon, and then improve the fatigue life of the cage.

Description

Technical Field

[0001] This application belongs to the field of cages for harmonic reducers, and particularly relates to a cage adapted for harmonic reducers. Background Technology

[0002] Harmonic reducers, as a crucial transmission device, are widely used in numerous industrial fields, especially in components such as robot joints. Among the core components of harmonic reducers, flexible bearings play a vital role. They not only transmit motion and power but also adapt to the unique transmission method of harmonic reducers through their elastic deformation. The cage of the harmonic reducer, as an important component of the flexible bearing, directly affects the operating performance and service life of the entire bearing and even the harmonic reducer.

[0003] In the actual operation of harmonic reducers, the wave generator is a key component that triggers a series of mechanical motion changes. When the wave generator operates, it causes the flexible bearing to undergo specific elliptical deformation. However, current harmonic reducer cage designs generally suffer from an unavoidable problem: they all include end ring structures. While the end rings play a role in enhancing structural stability and guiding the rolling elements to some extent, they face severe fatigue life issues in actual use. During periodic elliptical deformation, the bearing shape continuously changes, and the connection between the end ring and the beam experiences significant alternating stress. This stress concentration accelerates material fatigue damage. Therefore, existing technology needs further improvement and enhancement. Utility Model Content

[0004] This invention provides a cage adapted for harmonic reducers, which solves the problem that the connection between the end ring and the beam of the cage in a harmonic reducer is subject to large alternating stress, resulting in stress concentration, which accelerates material fatigue damage and seriously affects the fatigue life of the cage.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A cage for a harmonic reducer includes:

[0007] The cage body has rectangular crests and rectangular troughs, which are circumferentially continuous.

[0008] The rectangular crests and troughs respectively form a first pocket and a second pocket for accommodating cylindrical rollers, wherein the first pocket has a lower opening and the second pocket has an upper opening; the vertical peaks and valleys of the rectangular crests and troughs form window beams;

[0009] During the periodic elliptical deformation of the cage, the rectangular peaks and troughs can change the wavelength through deformation, uniformly disperse stress, reduce stress concentration, and thus improve the fatigue life of the cage.

[0010] In a preferred implementation, the first pocket and the second pocket are the same size.

[0011] In a preferred implementation, the rectangular peaks and troughs are integrally formed.

[0012] In the preferred implementation, the window beams formed by the vertical peak segments and the window beams formed by the vertical valley segments have the same thickness.

[0013] In the preferred implementation, the rectangular peaks and troughs have the same wavelength.

[0014] In the preferred implementation, the wavelengths of the rectangular peaks and troughs are different.

[0015] In a preferred implementation, the wavelength of the rectangular wave crest is twice the wavelength of the rectangular wave trough, and a dividing beam is provided at the center of the rectangular wave crest to divide it into two first pockets.

[0016] In a preferred implementation, the window beam has an arc-shaped surface that adapts to the profile of a cylindrical roller facing the first pocket surface or the second pocket surface.

[0017] In a preferred implementation, multiple rectangular peaks have the same wave height and multiple rectangular troughs have the same wave height, and the wave heights of the rectangular peaks and the rectangular troughs are equal.

[0018] The aforementioned structure offers the following advantages: The proposed cage for harmonic reducers eliminates the end ring structure and adopts a cage body structure with circumferentially continuous rectangular peaks and troughs. By eliminating the end ring, the design achieves the function of accommodating and guiding the cylindrical rollers through the formation of first and second pockets within the rectangular peaks and troughs, respectively. The first pocket has a lower opening, and the second pocket has an upper opening. Furthermore, the vertical peak and trough segments of the rectangular peaks and troughs form window beams. During periodic elliptical deformation, the rectangular peaks and troughs can change their wavelengths through deformation. This deformation method allows for a more uniform distribution of stress across the entire cage structure, avoiding excessive local stress concentration. This effectively solves the stress concentration problem caused by the end ring structure in existing technologies, contributing to improved cage fatigue life. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the present invention and constitute a part of this invention, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain this application and do not constitute an undue limitation of the present invention. In the drawings:

[0020] Figure 1 A schematic three-dimensional structural diagram of one embodiment of the cage for a harmonic reducer according to this application is shown;

[0021] Figure 2 A three-dimensional structural schematic diagram of another embodiment of the cage for a harmonic reducer adapted to this application is shown;

[0022] Figure 3 A schematic structural diagram of a side view of the cage for a harmonic reducer according to this application is shown;

[0023] Label Explanation:

[0024] 10. Rectangular peak; 100. First pocket; 101. Dividing beam; 11. Rectangular trough; 110. Second pocket; 12. Window beam; 120. Curved surface. Detailed Implementation

[0025] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit and scope of this invention. Therefore, the drawings and description are considered exemplary in nature and not restrictive.

[0026] In the description of this utility model, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In this utility model, unless otherwise expressly specified and limited, the first feature being "upper" or "lower" than the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium.

[0027] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral unit; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. However, specifying a direct connection indicates that the two connected entities do not have a connecting structure to establish a connection relationship, but are simply connected to form a whole through a connecting structure. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0028] In this utility model, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0029] The present invention will now be described with reference to the accompanying drawings.

[0030] The specific solution adopted is as follows:

[0031] like Figure 1-3 As shown, this utility model provides a cage adapted for harmonic reducers.

[0032] The cage body has rectangular peaks 10 and rectangular troughs 11, which are circumferentially continuous.

[0033] The rectangular crests and troughs are respectively formed with a first pocket 100 and a second pocket 110 for accommodating cylindrical rollers, wherein the first pocket has a lower opening and the second pocket has an upper opening; the vertical peaks and valleys of the rectangular crests and troughs form window beams 12.

[0034] During the periodic elliptical deformation of the cage, the rectangular peaks and troughs can change the wavelength through deformation, uniformly disperse stress, reduce stress concentration, and thus improve the fatigue life of the cage.

[0035] Traditional harmonic reducer cage designs typically include end ring structures. While these end rings enhance structural stability and guide the rolling elements, they also introduce fatigue life issues. This application's cage design for harmonic reducers eliminates the end ring structure, employing a cage body structure with continuously arranged rectangular crests and troughs circumferentially. By eliminating the end ring, the design achieves the function of accommodating and guiding the cylindrical rollers through the formation of a first pocket 100 and a second pocket 110 within the rectangular crests and troughs, respectively. The first pocket has a lower opening, and the second pocket has an upper opening. Furthermore, the vertical peak and valley segments of the rectangular crests and troughs form window beams, thus fulfilling the function of accommodating and guiding the cylindrical rollers. During periodic elliptical deformation, the rectangular crests and troughs can change their wavelengths through deformation. This deformation method allows for a more uniform distribution of stress throughout the overall cage structure, avoiding excessive local stress concentration. This effectively solves the stress concentration problem caused by the end ring structure in existing technologies, contributing to improved cage fatigue life.

[0036] In a preferred embodiment of this application, when the first pocket 100 and the second pocket 110 are of the same size, and the wavelengths of the rectangular crests and troughs are the same, placing cylindrical rollers of the same size results in a more uniform mass distribution of the cylindrical rollers circumferentially around the cage. During the high-speed operation of the harmonic reducer, this uniform mass distribution effectively reduces the centrifugal force differences caused by uneven mass distribution, thereby reducing vibration and noise, making the entire transmission system run more smoothly, and improving rotational balance. The rectangular crest and trough structure of the cage body, along with the raceways on the inner and outer rings, provides effective axial and circumferential restraint for the cylindrical rollers, enabling them to operate stably on predetermined tracks and ensuring the normal operation of the harmonic reducer.

[0037] In a preferred embodiment of this application, the rectangular crests and troughs are integrally formed, eliminating the connection gaps and weak points between them. During the operation of the harmonic reducer, the cage is subjected to periodic elliptical deformation and complex loads from the cylindrical rollers. The integrally formed structure can better resist these forces, reduce the risk of fracture due to stress concentration at the connection points, thereby significantly improving the overall structural strength and stability of the cage and extending its service life.

[0038] In a preferred embodiment of this application, the window beams formed by the vertical peak segments and the vertical valley segments have the same thickness. Window beams of the same thickness result in a more uniform mass distribution of the cage, reducing centrifugal force differences caused by uneven mass distribution, thereby reducing vibration and noise, and improving the rotational smoothness and accuracy of the harmonic reducer. When manufacturing the cage, the design of window beams of the same thickness simplifies the mold structure; the mold cavity and core designs do not need to consider the complex shape changes caused by window beams of different thicknesses, thus reducing the design difficulty and manufacturing cost of the mold.

[0039] In a preferred embodiment of this application, the rectangular crests and troughs have different wavelengths. In a specific embodiment, the wavelength of the rectangular crest is twice that of the rectangular trough. A dividing beam 101 is provided at the center of the rectangular crest to divide it into two first pockets, which can form an alternating structure of "long crest-short trough" or only one long crest or long trough, while the others are short crests or short troughs. These structural deformations can achieve a more uniform distribution of stress on the overall cage structure, avoiding excessive local stress concentration. Moreover, by setting such long crests and long troughs, the number and layout of cylindrical rollers can be adjusted, making the overall cage structure more reasonable.

[0040] As a preferred embodiment of this application, the window beam 12 is provided with an arc-shaped surface 120 adapted to the profile of the cylindrical roller facing the first pocket surface or the second pocket surface, which better restricts the rotation of the rolling element in the pocket, reduces abrupt changes in contact area (such as contact between a plane and the edge of a cylinder), and reduces friction.

[0041] In a preferred embodiment of this application, multiple rectangular peaks have the same wave height, and multiple rectangular troughs have the same wave height, with the wave heights of the rectangular peaks and troughs being equal. When the wave heights of the peaks and troughs are equal, the radial cross-section of the cage exhibits a periodically symmetrical structure (such as a sine wave), and the mass distribution is uniform along the circumferential direction. This symmetry can eliminate centrifugal force vibration caused by mass eccentricity. For robot fingers, reducing vibration can improve grasping accuracy.

[0042] For any parts not mentioned in this utility model, existing technologies can be used or referenced.

[0043] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in this utility model, and these should all be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A cage for a harmonic reducer, characterized in that, include: The cage body has rectangular peaks and rectangular troughs, which are circumferentially continuous. The rectangular crests and troughs respectively form a first pocket and a second pocket for accommodating cylindrical rollers, wherein the first pocket has a lower opening and the second pocket has an upper opening; the vertical peaks and valleys of the rectangular crests and troughs form window beams; During the periodic elliptical deformation of the cage, the rectangular peaks and troughs can change the wavelength through deformation, uniformly disperse stress, reduce stress concentration, and thus improve the fatigue life of the cage.

2. The cage for an adaptive harmonic reducer according to claim 1, characterized in that, The first pocket and the second pocket are the same size.

3. The cage for an adaptive harmonic reducer according to claim 1, characterized in that, The rectangular peaks and troughs are integrally formed.

4. The cage for an adaptive harmonic reducer according to claim 1, characterized in that, The window beams formed by the vertical peaks and the window beams formed by the vertical valleys have the same thickness.

5. The cage for an adaptive harmonic reducer according to claim 1, characterized in that, The wavelengths of the rectangular peaks and troughs are the same.

6. The cage for an adaptive harmonic reducer according to claim 1, characterized in that, The wavelengths of rectangular peaks and troughs are different.

7. The cage for an adaptive harmonic reducer according to claim 6, characterized in that, The wavelength of the rectangular wave crest is twice the wavelength of the rectangular wave trough, and a dividing beam is provided at the center of the rectangular wave crest to divide it into two first pockets.

8. The cage for an adaptive harmonic reducer according to claim 1, characterized in that, The window beam has an arc-shaped surface that adapts to the profile of a cylindrical roller facing the first pocket surface or the second pocket surface.

9. The cage for an adaptive harmonic reducer according to claim 1, characterized in that, Multiple rectangular peaks have the same wave height and multiple rectangular troughs have the same wave height, and the wave heights of the rectangular peaks and the rectangular troughs are equal.

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