Camshafts, wave generators, harmonic reducers, robots

Abstract

The present invention provides a camshaft, a wave generator, a harmonic reducer, and a robot. One camshaft includes a shaft body. Along the axial direction of the shaft body, the outer contour of the camshaft includes a first cam outer contour segment and a second cam outer contour segment. The major axis of the first cam outer contour segment is equal to the major axis of the second cam outer contour segment, and the minor axis of the first cam outer contour segment is smaller than the minor axis of the second cam outer contour segment. According to the camshaft, wave generator, harmonic reducer, and robot of the present invention, a first cam outer contour segment line and a second cam outer contour segment line are provided along the axial direction of the shaft body. Because the minor axis of the second cam outer contour segment line is larger than the minor axis of the first cam outer contour segment line, the camshaft has different gear tooth meshing ranges, which can compensate for the reduced stiffness of the flex spline and rigid spline teeth due to wear.

Description

Technical Field

[0001] The present invention belongs to the technical field of harmonic reducers, and in particular relates to a camshaft, a wave generator, a harmonic reducer, and a robot. Background Art

[0002] The harmonic reducer primarily consists of a circular, rigid internal gear with evenly spaced teeth, a coaxial, radially deformable, external flexible ring gear, and a cam wave generator within the flexible ring gear. Within a certain angular range on either side of the cam wave generator's maximum radius axis, the cam wave generator squeezes the flexible ring gear, causing it to deform radially. This causes the teeth on the external ring gear to embed within the teeth of the rigid internal gear, eliminating the gap between the flexspline and rigid teeth and allowing them to mesh with each other. This angular range is the meshing range of the harmonic reducer.

[0003] The meshing range of a harmonic reducer determines the number of simultaneously meshing tooth pairs, which in turn affects various reducer parameters, such as torsional stiffness and efficiency. As a harmonic reducer ages, both the flexspline and steel wheel teeth experience varying degrees of wear, increasing the gap between them. This, in turn, reduces the stiffness of the long-term harmonic reducer. Therefore, it is necessary to design a harmonic reducer that can compensate for this stiffness. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide a camshaft, a wave generator, a harmonic reducer, and a robot, which have a first cam outer contour segment line and a second cam outer contour segment line along the axial direction of the shaft body. Since the short axis of the second cam outer contour segment line is larger than the short axis of the first cam outer contour segment line, the camshaft has different gear tooth meshing ranges, which can compensate for the stiffness of the flexible wheel teeth and the rigid wheel teeth reduced due to wear.

[0005] In order to solve the above problems, the present invention provides a camshaft, including a shaft body. Along the axial direction of the shaft body, the outer contour of the camshaft includes a first cam outer contour segment and a second cam outer contour segment. The long axis of the first cam outer contour segment is equal to the long axis of the second cam outer contour segment, and the short axis of the first cam outer contour segment is smaller than the short axis of the second cam outer contour segment.

[0006] Optionally, when projected onto any radial plane of the shaft body, the major axis of the first cam outer contour segment coincides with the major axis of the second cam outer contour segment.

[0007] Optionally, the outer contour of the camshaft also includes a third cam outer contour segment, and the first cam outer contour segment, the second cam outer contour segment, and the third cam outer contour segment are arranged adjacent to each other in sequence along the axial direction of the shaft body, and the short axis of the second cam outer contour segment is smaller than the short axis of the third cam outer contour segment.

[0008] Optionally, when projected on any radial plane of the shaft body, the major axis of the first cam outer contour segment coincides with the major axis of the second cam outer contour segment, and the major axis of the second cam outer contour segment coincides with the major axis of the third cam outer contour segment.

[0009] Optionally, the first cam outer contour segment and the second cam outer contour segment are smoothly connected at their adjacent locations.

[0010] Optionally, an annular groove is provided at the junction of the first cam outer contour segment and the second cam outer contour segment.

[0011] Optionally, a retaining ring is detachably connected to the annular groove.

[0012] The present invention also provides a wave generator comprising the above-mentioned camshaft.

[0013] The present invention also provides a harmonic reducer, comprising the above-mentioned wave generator.

[0014] The present invention also provides a robot comprising the above-mentioned harmonic reducer.

[0015] The present invention provides a camshaft, a wave generator, a harmonic reducer, and a robot. The outer contour of the camshaft is designed along its axial direction to be a first cam outer contour segment and a second cam outer contour segment with the same major axis but different minor axes, so that the widths of the gear tooth meshing intervals of the first cam outer contour segment and the second cam outer contour segment are different. The larger the minor axis, the larger the width of the corresponding gear tooth meshing interval. In this way, after the camshaft is assembled to form a harmonic reducer and has been running for a long time, when the stiffness between the rigid internal gear and the flexible external gear is reduced due to wear between the gear teeth, the contact contour segment can be adjusted by adjusting the insertion depth of the camshaft shaft, for example, from the first cam outer contour segment to the second cam outer contour segment, so that the number of meshing gear tooth pairs between the rigid internal gear and the flexible external gear can be increased, thereby effectively compensating for the reduced stiffness. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the front structure of a camshaft according to an embodiment of the present invention;

[0017] Figure 2 for Figure 1 Side view of;

[0018] Figure 3This is a schematic diagram of a state in which a camshaft in a harmonic reducer according to another embodiment of the present invention contacts the cam through a first cam outer contour segment;

[0019] Figure 4 for Figure 3 Side view of;

[0020] Figure 5 This is a schematic diagram of a state in which a camshaft in a harmonic reducer according to another embodiment of the present invention contacts the cam through a second cam outer contour segment;

[0021] Figure 6 for Figure 5 Side view of;

[0022] Figure 7 This is a schematic diagram of a state in which a camshaft in a harmonic reducer according to another embodiment of the present invention contacts the cam through the third cam outer contour segment;

[0023] Figure 8 for Figure 7 side view.

[0024] The reference numerals indicate:

[0025] 1. Shaft; 11. First cam outer contour segment; 12. Second cam outer contour segment; 13. Third cam outer contour segment; 14. Ring groove; 2. Thin-walled ring; 3. Steel ball; 4. Flexible external gear; 5. Rigid internal gear. DETAILED DESCRIPTION

[0026] See also Figures 1 to 8 As shown, according to an embodiment of the present invention, a camshaft is provided, including a shaft body 1. Along the axial direction of the shaft body 1, the outer contour of the camshaft includes a first cam outer contour segment 11 and a second cam outer contour segment 12. The long axis of the first cam outer contour segment 11 is equal to the long axis of the second cam outer contour segment 12, and the short axis of the first cam outer contour segment 11 is smaller than the short axis of the second cam outer contour segment 12. In this technical solution, the outer contour of the camshaft is designed along its axial direction to have a first cam outer contour segment 11 and a second cam outer contour segment 12 with the same major axis but different minor axes, so that the widths of the gear tooth meshing intervals of the first cam outer contour segment 11 and the second cam outer contour segment 12 are different (specifically corresponding to the number of gear tooth pairs that are simultaneously meshed in the corresponding intervals). The larger the minor axis, the larger the width of the corresponding gear tooth meshing interval. In this way, after the camshaft is assembled to form a harmonic reducer and has been running for a long time, when the stiffness between the rigid internal gear 5 and the flexible external gear 4 is reduced due to wear between the gear teeth, the contact contour segment can be adjusted by adjusting the insertion depth of the camshaft shaft body 1, for example, from the first cam outer contour segment 11 to the second cam outer contour segment 12, so that the number of meshing gear tooth pairs between the rigid internal gear 5 and the flexible external gear 4 can be increased, thereby effectively compensating for the reduced stiffness.

[0027] In some embodiments, the outer profile of the camshaft further includes a third cam outer profile segment 13, and the first cam outer profile segment 11, the second cam outer profile segment 12, and the third cam outer profile segment 13 are arranged adjacent to each other in sequence along the axial direction of the shaft body 1, and the short axis of the second cam outer profile segment 12 is smaller than the short axis of the third cam outer profile segment 13. It is understandable that the outer profile of the camshaft can also be designed to have more segments along the axial direction of the shaft body 1. The present invention only schematically provides a specific implementation method of being divided into two or three segments, which does not mean that the situation of setting more segments is excluded. The design of more segments can make the camshaft's compensation effect on stiffness more lasting, and the width of its gear tooth meshing interval will be designed to be more refined.

[0028] It can be understood that the projections of the first cam outer contour segment 11 , the second cam outer contour segment 12 and the third cam outer contour segment 13 on any radial plane are all elliptical.

[0029] In some embodiments, when projected onto any radial plane of the shaft body 1, the major axis of the first cam outer profile segment 11 coincides with the major axis of the second cam outer profile segment 12. Thus, the connecting keyway of the shaft body 1 can be designed as a single structure, eliminating the need for multiple keyways to accommodate different cam outer profile segments. When the third cam outer profile segment 13 is included, the major axis of the first cam outer profile segment 11 coincides with the major axis of the second cam outer profile segment 12, and the major axis of the second cam outer profile segment 12 coincides with the major axis of the third cam outer profile segment 13.

[0030] Optionally, the first cam outer contour segment 11 and the second cam outer contour segment 12 are connected smoothly at their junction to prevent a step from being formed at the junction to hinder the insertion and adjustment of the camshaft. The smooth connection is specifically, for example, an inclined surface connection or an arc surface connection.

[0031] Optionally, an annular groove 14 is provided at the junction of the first cam outer contour segment 11 and the second cam outer contour segment 12 to clearly identify the contact surface range between the first cam outer contour segment 11 and the second cam outer contour segment 12, facilitating the operator's adjustment of the camshaft's insertion depth. Furthermore, a retaining spring is detachably connected to the annular groove 14. The retaining spring can be a shaft circlip. This retaining spring can limit the contact segment of the camshaft's outer contour when the motor output shaft moves axially, for example, preventing the contact segment from sliding from the second cam outer contour segment 12 to the first cam outer contour segment 11, thereby ensuring the rigidity of the gear tooth meshing and reducing the operating noise of the reducer.

[0032] It can be understood that when the outer contour of the camshaft has multiple outer contour segments, the adjacent parts of any two adjacent contour segments are smoothly connected. Preferably, both are provided with the annular groove 14 and the corresponding retaining spring.

[0033] According to an embodiment of the present invention, a wave generator is further provided, comprising the camshaft described above, wherein the outer contour of the camshaft is transitionally matched with a thin-walled ring 2 located on its outer periphery to facilitate adjustment of the camshaft's insertion depth, and a plurality of steel balls 3 are disposed between the thin-walled ring 2 and the inner hole wall of a flexible external gear 4, thereby achieving a circumferential rolling connection between the thin-walled ring 2 and the flexible external gear 4. Optionally, a first annular track is constructed on the inner hole wall of the flexible external gear 4, and a second annular track is constructed on the outer peripheral wall of the thin-walled ring 2, wherein the plurality of steel balls 3 are clamped by the first and second annular tracks, thereby limiting the axial and radial displacement of the steel balls 3.

[0034] According to an embodiment of the present invention, a harmonic reducer is further provided, comprising the above-mentioned wave generator, wherein the wave generator is meshed with the rigid internal gear 5 through the flexible external gear 4 thereof.

[0035] The present invention also provides a robot comprising the above-mentioned harmonic reducer.

[0036] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0037] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art may make various improvements and variations without departing from the technical principles of the present invention, and such improvements and variations shall also be considered within the scope of protection of the present invention.

Claims

1. A wave generator, characterized in that: The invention relates to a camshaft, wherein the camshaft comprises a shaft body (1); along the axial direction of the shaft body (1), the outer contour of the camshaft comprises a first cam outer contour segment (11) and a second cam outer contour segment (12); the long axis of the first cam outer contour segment (11) is equal to the long axis of the second cam outer contour segment (12), and the short axis of the first cam outer contour segment (11) is smaller than the short axis of the second cam outer contour segment (12); the outer contour of the camshaft further comprises a third cam outer contour segment (13); the first cam outer contour segment (11), the second cam outer contour segment (12), and the third cam outer contour segment (13) are The wheel outer contour segments (13) are arranged adjacent to each other in sequence along the axial direction of the shaft body (1), and the short axis of the second cam outer contour segment (12) is smaller than the short axis of the third cam outer contour segment (13); after the camshaft is assembled to form a harmonic reducer and runs for a long time, when the stiffness between the rigid internal gear and the flexible external gear decreases due to wear between the gear teeth, the insertion depth of the camshaft shaft body is adjusted to adjust the contact between the thin-walled ring (2) and one of the first cam outer contour segment (11) and the second cam outer contour segment (12), and the wave generator has only one thin-walled ring (2).

2. The wave generator according to claim 1, characterized in that When projected onto any radial plane of the shaft body (1), the major axis of the first cam outer contour segment (11) coincides with the major axis of the second cam outer contour segment (12).

3. The wave generator according to claim 1, characterized in that Projected on any radial plane of the shaft body (1), the major axis of the first cam outer contour segment (11) coincides with the major axis of the second cam outer contour segment (12), and the major axis of the second cam outer contour segment (12) coincides with the major axis of the third cam outer contour segment (13).

4. The wave generator according to claim 1, characterized in that The first cam outer contour segment (11) and the second cam outer contour segment (12) are smoothly connected at their adjacent locations.

5. The wave generator according to claim 4, characterized in that An annular groove (14) is provided at the junction of the first cam outer contour segment (11) and the second cam outer contour segment (12).

6. The wave generator according to claim 5, characterized in that A clamping spring is detachably connected to the annular groove (14).

7. A harmonic reducer, characterized in that: A wave generator comprising the wave generator according to any one of claims 1 to 6.

8. A robot, characterized in that: Including the harmonic reducer according to claim 7.

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