Harmonic reducer retainer with high compliance end ring

Abstract

The application discloses a harmonic reducer retainer with a high-flexibility end ring, which comprises an end ring and a plurality of window beams uniformly arranged on the end ring, a pocket hole for accommodating a rolling element is formed between adjacent window beams, and the pocket hole is provided with an opening on one side; the ring width of the end ring is greater than the radial beam width of the window beams; an arc-shaped notch is arranged on the part of the end ring exceeding the window beams; the number of the arc-shaped notches is matched with the number of the window beams and the arc-shaped notches are arranged correspondingly to the window beams; the flexibility of the end ring is increased by increasing the ring width of the end ring and introducing the arc-shaped notches on the over-wide part; during the operation of the harmonic reducer, the periodic elliptical deformation of the flexible bearing exerts an alternating tensile and compressive load on the retainer; local bending is generated at the arc-shaped notches due to the curvature transition; the stress is diffused to other areas of the end ring; the arc-shaped notches experience deformation recovery and unloading during the continuous rotation of the wave generator; the dispersed stress is not re-concentrated at the position, so that the fatigue life of the retainer is greatly improved.

Description

Technical Field

[0001] This application belongs to the field of harmonic reducer cages, and particularly relates to a harmonic reducer cage with a highly flexible end ring. Background Technology

[0002] As a key component of flexible bearings, the cage of a harmonic reducer directly and profoundly affects the overall operation and service life of the bearing and even the harmonic reducer. A well-designed and high-performance cage can effectively guide the rolling elements, ensuring their stable operation on the correct track, reducing friction and wear, thereby improving the overall performance and reliability of the bearing. In the actual operation of a harmonic reducer, the wave generator is the core component that triggers a series of precision mechanical motion changes. When the wave generator starts working, it causes the flexible bearing to produce a specific elliptical deformation to achieve the unique transmission function of the harmonic reducer. However, the current design of existing harmonic reducer cage structures has a common problem that urgently needs to be solved.

[0003] Existing cage structures generally include a complete end ring structure, taking the common single-end ring crown type cage as an example. The end ring does indeed play a role in enhancing structural stability to a certain extent, providing additional support and maintaining structural integrity under high-speed operation and complex stress conditions. Simultaneously, the end ring also guides the rolling elements, ensuring they roll on the correct path and reducing offset and collisions. However, during the operation of a harmonic reducer, the flexible bearing undergoes continuous periodic elliptical deformation, causing the cage to be subjected to complex alternating stresses. The connection between the end ring and the beam, due to the abrupt change in structural shape, becomes a "hotspot" for stress concentration. Under the action of periodic elliptical deformation, this area bears significant alternating stress, and this continuous high-stress state accelerates material fatigue damage. Over time, this area is often the first to fracture, leading to the failure of the entire cage, severely affecting the normal operation of the harmonic reducer and shortening its service life. Therefore, existing technology urgently needs further improvement and enhancement. Utility Model Content

[0004] This invention provides a harmonic reducer cage with a highly flexible end ring, which solves or alleviates the problem of geometric abrupt changes at the connection between the end ring and the beam of the harmonic reducer cage. Under the action of periodic elliptical deformation, this part will be subjected to large alternating stress, resulting in early fracture failure.

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

[0006] A harmonic reducer cage with a high flexibility end ring includes an end ring and multiple window beams evenly arranged on the end ring. Adjacent window beams form pockets to accommodate rolling elements. The pockets are open on one side. The ring width of the end ring is greater than the beam width of the window beams in the radial direction. The extra-wide transition section of the end ring beyond the window beams is provided with arc-shaped notches. The number of arc-shaped notches is adapted to the number of window beams and is set corresponding to the window beams.

[0007] In a preferred embodiment, the outer surface of the window beam is flush with the outer diameter surface of the end ring, and the arc-shaped notch is formed in the end ring portion between the inner surface of the window beam and the inner diameter surface of the end ring.

[0008] In a preferred embodiment, the inner surface of the window beam is flush with the inner diameter surface of the end ring, and the arc-shaped notch is formed in the end ring portion between the inner and outer surfaces of the window beam and the outer diameter surface of the end ring.

[0009] In the preferred implementation, the maximum opening distance of the arc-shaped notch is equal to the maximum beam width of the window beam along the circumferential direction.

[0010] In the preferred implementation, the junction between the arc-shaped notch and the inner or outer diameter surface of the end ring is a rounded transition.

[0011] In the preferred implementation, the depth of the arc-shaped notch accounts for 50% to 90% of the ultra-wide transition section of the end ring.

[0012] In a preferred embodiment, the window beam has curved surfaces facing both the inner and outer rings.

[0013] In the preferred implementation, the window beam and the end ring are integrally formed.

[0014] In a preferred implementation, the side of the window beam facing the pocket has an arc-shaped contact surface that adapts to the profile of the rolling element.

[0015] The above structure has the following beneficial effects:

[0016] By increasing the ring width of the end ring and introducing an arc-shaped notch in the extra-wide section, the flexibility of the end ring is increased. During the operation of the harmonic reducer, the periodic elliptical deformation of the flexible bearing applies alternating tensile and compressive loads to the cage. Local bending occurs at the arc-shaped notch due to curvature transition. When the arc-shaped notch deforms, the stress diffuses to other areas of the end ring. As the wave generator rotates continuously, the arc-shaped notch undergoes deformation recovery and unloading, dispersing the stress. By setting N arc-shaped notches at the corresponding positions of N window beams, a periodic stress dispersion array is formed, avoiding single-point failure that leads to chain fracture, thereby greatly improving the fatigue life of the cage. Attached Figure Description

[0017] 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:

[0018] Figure 1 A three-dimensional structural schematic diagram of a first embodiment of the harmonic reducer cage with a high-flexibility end ring of this application is shown.

[0019] Figure 2 A three-dimensional structural schematic diagram of a second embodiment of the harmonic reducer cage with a high-flexibility end ring of this application is shown.

[0020] Figure 3 A top view of the structure of the second embodiment of this application is shown;

[0021] Label Explanation:

[0022] 1. End ring; 10. Arc-shaped notch; 2. Window beam; 20. Arc surface; 21. Arc-shaped contact surface; 3. Pocket. Detailed Implementation

[0023] 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.

[0024] 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.

[0025] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., 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 main bodies at the connection point are not connected by an intermediate structure, 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.

[0026] 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.

[0027] The present invention will now be described with reference to the accompanying drawings.

[0028] The specific solution adopted is as follows:

[0029] like Figure 1-3 As shown, this utility model provides a harmonic reducer cage with a highly flexible end ring, including an end ring 1 and multiple window beams 2 evenly arranged on the end ring. Adjacent window beams form pockets to accommodate rolling elements. The pockets 3 are open on one side. The ring width of the end ring is greater than the beam width of the window beams in the radial direction. The part of the end ring that extends beyond the window beams is provided with an arc-shaped notch 10. The number of arc-shaped notches is adapted to the number of window beams and is set corresponding to the window beams.

[0030] In this application, by increasing the ring width of the end ring 1 and introducing an arc-shaped notch 10 in the extra-wide portion, the flexibility of the end ring is increased. During the operation of the harmonic reducer, the periodic elliptical deformation of the flexible bearing applies alternating tensile and compressive loads to the cage. Local bending occurs at the arc-shaped notch due to the curvature transition. The opening width slightly expands or shrinks with increasing stress, forming a reserve of elastic strain energy. When the arc-shaped notch deforms, the stress diffuses to other areas of the end ring. As the wave generator rotates continuously, the arc-shaped notch undergoes deformation recovery and unloading. For example, the notch opening slightly expands or shrinks and then elastically recovers, but the dispersed stress no longer re-accumulates at this position. N arc-shaped notches are set at the corresponding positions of N window beams to form a periodic stress dispersion array, avoiding single-point failure that leads to chain fracture, thereby greatly improving the fatigue life of the cage.

[0031] In a preferred embodiment of this application, the outer surface of the window beam 2 is flush with the outer diameter surface of the end ring. This maintains a narrower width for the retainer, suitable for the gap between the inner and outer rings of tiny bearings such as robot finger joints. The arc-shaped notch 10 is formed in the end ring portion between the outer surface of the window beam and the inner diameter surface of the end ring. Placing the arc-shaped notch 10 on the inner diameter side disperses the high stress on the inner diameter side, and by thinning the material on the inner diameter side, weight reduction is achieved while maintaining the overall rigidity of the end ring.

[0032] As a preferred embodiment of this application, the inner surface of the window beam 2 is flush with the inner diameter surface of the end ring, and the arc-shaped notch 10 is opened in the end ring portion between the inner and outer surfaces of the window beam and the outer diameter surface of the end ring. This can also maintain a narrower width of the retainer, place the arc-shaped notch on the outer diameter side, disperse the high stress on the outer diameter side, and achieve weight reduction while maintaining the overall rigidity of the end ring.

[0033] As a preferred embodiment of this application, an ultra-wide transition section can also be added simultaneously on the inner and outer sides of the window beam. An arc-shaped notch is opened at the radially symmetrical position of the ultra-wide section on the inner and outer sides to disperse the high stress on the inner and outer diameter sides. However, the width of the ultra-wide transition section needs to be reasonably designed to ensure that the total width of the cage can be used in the tiny bearing of the robot joint.

[0034] See Figure 3 The maximum opening distance of the arc-shaped notch 10 is equal to the maximum beam width of the window beam 2 along the circumference.

[0035] If the arc-shaped notch is too wide, excessive material is removed from the end ring, resulting in low local stiffness and making the end ring prone to fracture under alternating loads. If the arc-shaped notch is too narrow, it cannot cover the high-stress transition zone between the window beam and the end ring, and the stress remains concentrated at the connection. In this embodiment, the arc-shaped notch precisely covers the critical stress path between the window beam and the end ring, so that the deformation of the window beam and the elastic deformation of the notch are triggered almost simultaneously. The stress is "smoothly transitioned" from the root of the window beam to both sides of the notch, resulting in better stress dispersion and significantly improving the fatigue resistance of the cage.

[0036] Furthermore, the junction between the arc-shaped notch and the inner or outer diameter surface of the end ring is a rounded transition. By introducing a rounded transition, stress concentration is avoided, and the stress flow is made to pass smoothly through the dispersion area.

[0037] In a preferred embodiment of this application, the depth of the arc-shaped notch is 50% to 90% of the extra-wide portion of the end ring. If the depth is less than 50%, the arc-shaped notch cannot cover the high-stress transition zone between the window beam and the end ring, and the stress is still concentrated at the root of the window beam. If the depth is greater than 90%, the extra-wide portion of the end ring is excessively cut off, and the remaining material is insufficient to withstand the axial compressive stress, causing the stress to accumulate at the root of the notch. However, the depth setting of this application allows the stress to be transmitted from the root of the window beam along both sides of the notch to the extra-wide portion of the end ring in two paths. The arc-shaped notch can provide sufficient arc length for the material to elastically stretch / compress, thereby better dispersing the stress and improving the life of the cage.

[0038] As a preferred embodiment of this application, the window beam is provided with an arc surface 20 on the inner and outer surfaces. The arc surface increases the local flexibility of the window beam, allowing it to undergo controllable elastic bending under load, and significantly enhancing its fatigue resistance.

[0039] As a preferred embodiment of this application, the window beam and the end ring are integrally formed, which makes the entire cage structure stronger, has no joints, and has a long service life for periodic elliptical deformation.

[0040] As a preferred embodiment of this application, the side of the window beam facing the pocket has an arc-shaped contact surface 21 that adapts to the profile of the rolling element. The arc-shaped contact surface can better confine the roller within the pocket, reducing the problems of roller rotation collision, rotation obstruction, and friction caused by abrupt shape changes.

[0041] For any parts not mentioned in this utility model, existing technologies can be used or referenced.

[0042] 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 harmonic reducer cage with a high-flexibility end ring, comprising an end ring and a plurality of window beams evenly arranged on the end ring, wherein adjacent window beams form pockets for accommodating rolling elements, and one side of the pockets is open, characterized in that, The width of the end ring is greater than the width of the window beam along the radial direction. The extra-wide transition section of the end ring beyond the window beam is provided with an arc-shaped notch. The number of arc-shaped notches is adapted to the number of window beams and is set accordingly.

2. The harmonic reducer cage with high flexibility end ring according to claim 1, characterized in that, The outer surface of the window beam is flush with the outer diameter surface of the end ring, and the arc-shaped notch is opened in the end ring portion between the inner surface of the window beam and the inner diameter surface of the end ring.

3. The harmonic reducer cage with high flexibility end ring according to claim 1, characterized in that, The inner surface of the window beam is flush with the inner diameter surface of the end ring, and the arc-shaped notch is opened in the end ring part between the inner and outer surfaces of the window beam and the outer diameter surface of the end ring.

4. The harmonic reducer cage with high flexibility end ring according to claim 1, characterized in that, The maximum opening distance of the arc-shaped notch is equal to the maximum beam width along the circumference of the window beam.

5. The harmonic reducer cage with a high-flexibility end ring according to claim 2 or 3, characterized in that, The junction between the arc-shaped notch and the inner or outer diameter surface of the end ring is a rounded transition.

6. The harmonic reducer cage with a high-flexibility end ring according to claim 2 or 3, characterized in that, The depth of the arc-shaped notch accounts for 50% to 90% of the ultra-wide transition section of the end ring.

7. The harmonic reducer cage with high flexibility end ring according to claim 1, characterized in that, The window beam has curved surfaces facing both the inner and outer rings.

8. The harmonic reducer cage with high flexibility end ring according to claim 1, characterized in that, The window beam and end ring are integrally molded structures.

9. The harmonic reducer cage with high flexibility end ring according to claim 1, characterized in that, The side of the window beam facing the pocket has an arc-shaped contact surface adapted to the profile of the rolling element.

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