Cam, wave generator and harmonic reducer

Abstract

The invention provides a cam, a wave generator and a harmonic reducer, the cam comprises a cam body, symmetrically distributed strip-shaped holes are formed in the two sides of the center of the cam body in the long axis direction of the cam body, and the strip-shaped holes are through in the axial direction of the cam body; on the end face of the cam body, the extending track of the strip-shaped hole stretches across the long axis of the cam body and is concave towards the center of the cam body. After the cam is matched with the flexible bearing, a buffer space capable of providing elastic deformation and absorbing vibration is formed in the strip-shaped hole. According to the arrangement, the cam with the through hole in the shape is designed and constructed in the position, the balance weight of the cam is reduced, a buffer space for providing elastic deformation and absorbing vibration can be formed in the strip-shaped hole, high-speed, low-noise and small-vibration operation of the harmonic reducer is facilitated, and the problem that how to optimize the structure of the harmonic reducer in the prior art is solved. And the performance in the aspects of light weight, high speed, low noise and small vibration is improved.

Description

Technical Field

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

[0002] A harmonic reducer is a gear transmission structure that relies on a wave generator equipped with a flexible bearing to make the flexible wheel produce controllable elastic deformation and mesh with the rigid wheel to transmit motion and power. The wave generator consists of a cam and a flexible bearing, and the outer contour of the cam is usually elliptical.

[0003] In recent years, with the rapid development of the robotics industry, especially the updating and iteration of collaborative robots and humanoid robots, the requirements for harmonic reducers used in robots have gradually increased. However, the performance of harmonic reducers in the existing technology in terms of light weight, high speed, low noise and low vibration is difficult to meet the design requirements of robots.

[0004] Therefore, it is particularly important to optimize the structure of the harmonic reducer to improve its performance in terms of light weight, high speed, low noise and low vibration. Summary of the invention

[0005] In view of this, the present application provides a cam, a wave generator and a harmonic reducer to solve the problem in the prior art of how to optimize the structure of the harmonic reducer to improve the performance in terms of light weight, high speed, low noise and low vibration.

[0006] In order to achieve the above objectives, this application provides the following technical solutions: A cam, applied to a harmonic reducer, comprises a cam body, wherein in the long axis direction of the cam body, two sides of the center of the cam body are provided with symmetrically distributed strip holes, and the strip holes penetrate along the axial direction of the cam body; On the end surface of the cam body, the extension track of the strip-shaped hole crosses the long axis of the cam body and is concave toward the center of the cam body; After the cam is matched with the flexible bearing, a buffer space capable of providing elastic deformation and absorbing vibration is formed in the strip-shaped hole.

[0007] Optionally, the side of the strip-shaped hole close to the outer edge of the cam body is the outer hole wall, and the side of the strip-shaped hole away from the outer edge of the cam body is the inner hole wall, wherein: The outer hole wall is a plane or a curved surface or multiple curved surfaces or a combination of a plane and a curved surface; and / or, The inner hole wall is a plane or a curved surface or multiple curved surfaces or a combination of a plane and a curved surface.

[0008] Optionally, a side of the strip-shaped hole close to the outer edge of the cam body is an outer hole wall, and a side of the strip-shaped hole away from the outer edge of the cam body is an inner hole wall; The outer hole wall and the inner hole wall are both arc surfaces, and the radius of the outer hole wall is greater than or equal to the radius of the inner hole wall.

[0009] Optionally, the outer hole wall and the inner hole wall are transitionally connected via a rounded surface.

[0010] Optionally, the extension trajectory of the strip-shaped hole is symmetrical about the long axis of the cam body.

[0011] Optionally, in the long axis direction of the cam body, the distance between the most concave part of the outer hole wall and the outer edge of the cam body is d1, the distance between the most concave parts of the two strip holes is D1, and the long axis outer diameter of the cam body is D, wherein: D = D1 + 2 × d1; D and D1 are positively correlated, and D1 and d1 are negatively correlated.

[0012] Optionally, in the long axis direction of the cam body, the distance between the most concave part of the outer hole wall and the outer edge of the cam body is d1, and the long axis outer diameter of the cam body is D, wherein: d1=a×D, 0.0484≤a≤0.0645.

[0013] Optional, a takes the value of 0.0548.

[0014] Optionally, the radius of the outer hole wall is r1, and the radius of the inner hole wall is r2, wherein: r1=b×r2, 1.25≤b≤7.5; 3mm≤r2≤5mm.

[0015] Optionally, b is taken as 2.5, and / or r2 is taken as 4 mm.

[0016] Optionally, on the end surface of the cam body, the centers of the rounded surfaces at both ends of the strip-shaped hole are both located on a pitch circle, the pitch circle has the center of the cam body as the center, the radius of the pitch circle is R1, and the outer diameter of the major axis of the cam body is D, wherein: 2×R1=c×D, 0.8862≤c≤0.9136.

[0017] Optionally, c takes the value 0.9032.

[0018] Optionally, the radius of the fillet surface is r3, 0.1mm≤r3≤0.5mm; and / or, The angle between the line between the center of the fillet surface and the center of the cam body and the major axis of the cam body is α, 8°≤α≤12°.

[0019] A wave generator comprises a flexible bearing and any one of the above cams, wherein the flexible bearing is sleeved on the cam.

[0020] A harmonic reducer comprises a rigid wheel, a flexible wheel and the above-mentioned wave generator.

[0021] The cam provided in the present application is applied to a harmonic reducer, and includes a cam body. In the long axis direction of the cam body, symmetrically distributed strip holes are opened on both sides of the center of the cam body, and the strip holes pass through the axial direction of the cam body; on the end face of the cam body, the extension trajectory of the strip holes spans the long axis of the cam body and is concave toward the center of the cam body; after the cam is matched with the flexible bearing, a buffer space that can provide elastic deformation and absorb vibration is formed in the strip holes. With such arrangement, the interior of the cam body has a design with local material missing at the position on the major axis, and a strip hole in the form of a through hole is formed, and the strip hole is concave; after many experiments and verifications, the applicant found that the cam designed and constructed with the through hole in the above-mentioned form at the above-mentioned position not only reduces its own counterweight, but also can ensure the structural strength and structural mechanical properties of the cam body due to the local material missing on the longer major axis; at the same time, during the operation of the harmonic reducer, a buffer space that provides elastic deformation and absorbs vibration can be formed in the strip hole having a certain span in both the major axis direction and the minor axis direction, so that the load distribution of the harmonic reducer during operation is more uniform, which is conducive to the high-speed, low-noise and low-vibration operation of the harmonic reducer. Compared with the conventional cam in the prior art, the cam provided by the present application can meet the performance requirements in terms of lightweight, high speed, low noise and low vibration, and solves the problem of how to optimize the structure of the harmonic reducer in the prior art to improve the performance in terms of lightweight, high speed, low noise and low vibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of the cam structure provided in an embodiment of the present application.

[0024] Figure 2 This is a front view of the cam provided in an embodiment of the present application.

[0025] Figure 3A schematic cross-sectional view of a cam broken along the major axis provided in an embodiment of the present application.

[0026] Figure 4 A front view of a cam with dimension markings provided in an embodiment of the present application.

[0027] exist Figure 1-Figure 4 middle: 1. Cam body; 101. Strip hole. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0029] The applicant has found that the cam, as a power component of the harmonic reducer, has a very important influence on the performance of the harmonic reducer in terms of its structural design and size parameters.

[0030] like Figure 1-Figure 4 As shown, the embodiment of the present application provides a cam, which is applied to a harmonic reducer, and includes a cam body 1. In the long axis direction of the cam body 1, symmetrically distributed strip holes 101 are opened on both sides of the center of the cam body 1, and the strip holes 101 pass through the axial direction of the cam body 1; on the end face of the cam body 1, the extension track of the strip holes 101 crosses the long axis of the cam body 1 and is concave toward the center of the cam body 1; after the cam is matched with the flexible bearing, a buffer space that can provide elastic deformation and absorb vibration is formed in the strip holes 101. As is known, the center of the cam body 1 is at the intersection of its long axis and short axis.

[0031] With such arrangement, the interior of the cam body 1 has a design with partial material missing at a position on the long axis, and a strip hole 101 in the form of a through hole is formed, and the strip hole 101 is concave; after many experiments and verifications, the applicant found that the cam designed and constructed with the above-mentioned through hole in the above-mentioned position not only reduces its own counterweight, but also ensures the structural strength and structural mechanical properties of the cam body 1 due to the partial material missing on the long axis with a longer size; at the same time, during the operation of the harmonic reducer, a buffer space that provides elastic deformation and absorbs vibration can be formed in the strip hole 101 having a certain span in both the long axis direction and the short axis direction, so that the load distribution of the harmonic reducer during operation is more uniform, which is conducive to the high-speed, low-noise and low-vibration operation of the harmonic reducer. Compared with the conventional cam in the prior art, the cam provided by the present application can meet the performance requirements in terms of lightweight, high speed, low noise and low vibration, and solves the problem of how to optimize the structure of the harmonic reducer in the prior art to improve the performance in terms of lightweight, high speed, low noise and low vibration.

[0032] In some preferred embodiments, the distance between the strip hole 101 and the outer edge of the cam body 1 is smaller than the distance between the strip hole 101 and the inner edge of the cam body 1, that is, the strip hole 101 is located between the inner edge and the outer edge of the cam body 1 and close to the outer edge. With this arrangement, after the cam is matched with the flexible bearing, the strip hole 101 has better performance in providing elastic deformation and absorbing vibration.

[0033] This application abandons the inherent design ideas for cams in this field. In the long-term product development and improvement practice, various cam structure designs are studied to explore the impact on the performance of the harmonic reducer. It is found that a through hole is opened inside the cam body 1 on the long axis and close to the outer edge. This is a completely different material reduction design scheme from the past. Through the breakthrough design in details, after the cam is assembled to the harmonic reducer, the performance of the harmonic reducer in many of the above aspects is improved. Outstanding technical effects have been achieved through a completely different design idea.

[0034] Moreover, the cam provided in this application has been tested and verified to have good performance in the application of small harmonic reducers, which is helpful for the design direction of miniaturization of harmonic reducers.

[0035] For the convenience of description, the side of the strip hole 101 close to the outer edge of the cam body 1 is the outer hole wall, and the side of the strip hole 101 away from the outer edge of the cam body 1 is the inner hole wall.

[0036] In some optional embodiments, regarding the shape design of the outer hole wall, the outer hole wall is a plane or a curved surface or multiple curved surfaces or a combination of a plane and a curved surface; regarding the shape design of the inner hole wall, the inner hole wall is a plane or a curved surface or multiple curved surfaces or a combination of a plane and a curved surface. Therefore, based on various design options of the outer hole wall and the inner hole wall, the strip hole 101 has various possible forms.

[0037] In some preferred embodiments, both the outer hole wall and the inner hole wall are cambered surfaces, and the radius of the outer hole wall is greater than or equal to the radius of the inner hole wall. In other words, the strip hole 101 is a U-shaped hole or a crescent hole. In this way, both the outer hole wall and the inner hole wall are cambered surfaces, which can take into account the advantages of low cam processing difficulty and better performance.

[0038] Furthermore, it is preferably configured such that the radius of the outer hole wall is greater than or equal to the radius of the inner hole wall. Figure 1-Figure 4 This situation is shown as an example in FIG.

[0039] In some specific embodiments, the outer hole wall and the inner hole wall are transitionally connected by a rounded surface. In other words, both ends of the extension track of the strip hole 101 are transitionally connected arc surfaces. This arrangement can reduce stress concentration in the strip hole 101.

[0040] In some preferred embodiments, the extension track of the strip hole 101 is symmetrical about the long axis of the cam body 1, that is, the most concave part of the strip hole 101 is on the long axis. Such a setting, after testing and verification, compared with the implementation method in which the extension track of the strip hole 101 is asymmetrical about the long axis of the cam body 1, the symmetrical design is conducive to improving the uniformity of load distribution of the harmonic reducer during operation after the cam is assembled in the harmonic reducer.

[0041] The design parameter values ​​of the cam body 1 are not arbitrary, but need to follow a certain design basis, so as to ensure the structural strength while achieving the desired technical effect of optimizing the performance of the harmonic reducer.

[0042] In some specific embodiments, based on the design basis that the extension trajectory of the strip hole 101 is symmetrical about the long axis of the cam body 1, in the long axis direction of the cam body 1, the distance between the most concave part of the outer hole wall and the outer edge of the cam body 1 is d1, the distance between the most concave parts of the two strip holes 101 is D1, and the outer diameter of the long axis of the cam body 1 is D, wherein: D=D1+2×d1; D and D1 are positively correlated, that is, the larger D is, the larger the design value of D1 is, and D1 and d1 are negatively correlated, that is, the larger D1 is, the smaller the design value of d1 is.

[0043] With such a configuration, the span D1 of the most concave part of the outer hole wall of the two strip holes 101 on the long axis can be first determined through the basic parameter of the long axis outer diameter D of the cam body 1, and then the distance d1 between the most concave part of the outer hole wall and the outer edge of the cam body 1 can be designed to complete the relevant parameter design of the main hole. Following this design idea is conducive to the reasonable and rapid completion of the overall parameter design of the cam.

[0044] In some other specific embodiments, based on the design basis that the extension track of the strip hole 101 is symmetrical about the long axis of the cam body 1, in the long axis direction of the cam body 1, the distance between the most concave part of the outer hole wall and the outer edge of the cam body 1 is d1, and the long axis outer diameter of the cam body 1 is D, wherein: d1=a×D, 0.0484≤a≤0.0645.

[0045] With such a setting, after testing and verification, the cam designed according to the above-mentioned ratio range can help ensure that after the cam is assembled in the harmonic reducer, the uniformity of load distribution of the harmonic reducer during operation is improved.

[0046] For example, the value of a is 0.0548. Among the values ​​that can be explored, this setting can achieve the best effect.

[0047] In some other specific embodiments, based on the design basis that both the outer hole wall and the inner hole wall are arc surfaces, the radius of the outer hole wall is r1, and the radius of the inner hole wall is r2, wherein: r1=b×r2, 1.25≤b≤7.5; 3mm≤r2≤5mm.

[0048] With such a setting, after testing and verification, the cam designed according to the above-mentioned ratio range can help ensure that after the cam is assembled in the harmonic reducer, the uniformity of load distribution of the harmonic reducer during operation is improved.

[0049] For example, b is 2.5 and r2 is 4 mm. Among the values ​​that can be explored, this setting can achieve the best effect.

[0050] In some other specific embodiments, on the end surface of the cam body 1, the centers of the rounded surfaces at both ends of the strip hole 101 are located on the pitch circle, the pitch circle is centered on the center of the cam body 1, the radius of the pitch circle is R1, and the outer diameter of the major axis of the cam body 1 is D, wherein: 2×R1=c×D, 0.8862≤c≤0.9136.

[0051] In this way, since the curvature of the outer hole wall and the inner hole wall is difficult to be directly reflected by the relevant parameters of the outer hole wall and the inner hole wall, it can be reflected indirectly through the position of the center of the fillet surface. In order to facilitate the provision of the parameter design adjustment range, the above relationship is formed. After testing and verification, the cam designed according to the above-mentioned proportional range can help ensure that after the cam is involved in the assembly of the harmonic reducer, the uniformity of the load distribution of the harmonic reducer during operation is improved.

[0052] For example, the value of c is 0.9032. Among the values ​​that can be explored, this setting can achieve the best effect.

[0053] In some other specific embodiments, the radius of the fillet surface is r3, 0.1mm≤r3≤0.5mm; the angle between the line between the center of the fillet surface and the center of the cam body 1 and the long axis of the cam body 1 is α, 8°≤α≤12°.

[0054] In this way, the span of the strip hole 101 in the short axis direction can be reflected by the above-mentioned angle α. After testing and verification, the cam designed according to the above-mentioned proportional range can help ensure that after the cam is assembled in the harmonic reducer, the uniformity of the load distribution of the harmonic reducer during operation is improved.

[0055] For example, r3 is 0.3 mm, and α is 10°. Among the values ​​that can be explored, this setting can achieve the best effect.

[0056] It should be noted that since the strip hole 101 plays a key role in providing a buffer space for elastic deformation and absorbing vibration, and the strip hole 101 is of a special-shaped design, the adjustment of many detailed parameters of the strip hole 101 can bring about different degrees of optimized performance. The applicant has obtained the above-mentioned parameter design ranges through a large number of comparative tests, so that a cam with better performance can be obtained within the explorable range.

[0057] Based on the above cam, the embodiment of the present application further provides a wave generator, which includes a flexible bearing and the above cam, and the flexible bearing is sleeved on the cam. Since the wave generator has the above cam, the beneficial effects of the wave generator brought by the cam can be seen in the above content, which will not be repeated here.

[0058] Based on the above-mentioned wave generator, the embodiment of the present application further provides a harmonic reducer, which includes a rigid wheel, a flexible wheel and the above-mentioned wave generator, wherein the wave generator is sleeved inside the flexible wheel, the flexible wheel is sleeved inside the rigid wheel, and the flexible wheel and the rigid wheel are meshed with teeth. Since the harmonic reducer has the above-mentioned wave generator, the beneficial effects of the harmonic reducer brought by the wave generator can be found in the above content, which will not be repeated here.

[0059] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0060] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0061] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0062] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0063] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly explain the technical solutions and cannot be used to limit the scope of protection of the present application.

[0064] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A cam, characterized in that: Applicable to a harmonic reducer, comprising a cam body (1), wherein in the long axis direction of the cam body (1), two sides of the center of the cam body (1) are provided with symmetrically distributed strip holes (101), and the strip holes (101) penetrate the cam body (1) along the axial direction; On the end surface of the cam body (1), the extension track of the strip-shaped hole (101) spans the long axis of the cam body (1) and is concave toward the center of the cam body (1); After the cam is matched with the flexible bearing, a buffer space capable of providing elastic deformation and absorbing vibration is formed in the strip-shaped hole (101).

2. The cam according to claim 1, characterized in that: The side of the strip-shaped hole (101) close to the outer edge of the cam body (1) is the outer hole wall, and the side of the strip-shaped hole (101) away from the outer edge of the cam body (1) is the inner hole wall, wherein: The outer hole wall is a plane or a curved surface or multiple curved surfaces or a combination of a plane and a curved surface; and / or, The inner hole wall is a plane or a curved surface or multiple curved surfaces or a combination of a plane and a curved surface.

3. The cam according to claim 1, characterized in that: The side of the strip-shaped hole (101) close to the outer edge of the cam body (1) is an outer hole wall, and the side of the strip-shaped hole (101) away from the outer edge of the cam body (1) is an inner hole wall; The outer hole wall and the inner hole wall are both arc surfaces, and the radius of the outer hole wall is greater than or equal to the radius of the inner hole wall.

4. The cam according to claim 2 or 3, characterized in that: The outer hole wall and the inner hole wall are transitionally connected via a rounded surface.

5. The cam according to claim 2 or 3, characterized in that: The extension track of the strip-shaped hole (101) is symmetrical about the long axis of the cam body (1).

6. The cam according to claim 5, characterized in that: In the long axis direction of the cam body (1), the distance between the most concave part of the outer hole wall and the outer edge of the cam body (1) is d1, the distance between the most concave parts of the two strip-shaped holes (101) is D1, and the long axis outer diameter of the cam body (1) is D, wherein: D = D1 + 2 × d1; D and D1 are positively correlated, and D1 and d1 are negatively correlated.

7. The cam according to claim 5, characterized in that: In the long axis direction of the cam body (1), the distance between the most concave part of the outer hole wall and the outer edge of the cam body (1) is d1, and the long axis outer diameter of the cam body (1) is D, wherein: d1=a×D, 0.0484≤a≤0.0645.

8. The cam according to claim 7, characterized in that: The value of a is 0.0548.

9. The cam according to claim 3, characterized in that: The radius of the outer hole wall is r1, and the radius of the inner hole wall is r2, wherein: r1=b×r2, 1.25≤b≤7.5; 3mm≤r2≤5mm.

10. The cam according to claim 9, characterized in that: b is taken as 2.5, and / or r2 is taken as 4 mm.

11. The cam according to claim 4, characterized in that: On the end surface of the cam body (1), the centers of the rounded corners at both ends of the strip hole (101) are located on a pitch circle, the pitch circle has the center of the cam body (1) as its center, the radius of the pitch circle is R1, and the outer diameter of the major axis of the cam body (1) is D, wherein: 2×R1=c×D, 0.8862≤c≤0.9136.

12. The cam according to claim 11, characterized in that The value of c is 0.9032.

13. The cam according to claim 4, characterized in that: The radius of the fillet surface is r3, 0.1mm≤r3≤0.5mm; and / or, The angle between the line between the center of the fillet surface and the center of the cam body (1) and the major axis of the cam body (1) is α, 8°≤α≤12°.

14. A wave generator, characterized in that: It comprises a flexible bearing and a cam as described in any one of claims 1 to 13, wherein the flexible bearing is sleeved on the cam.

15. A harmonic reducer, characterized in that: It comprises a rigid wheel, a flexible wheel and the wave generator as claimed in claim 14.

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