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, grooves are formed in the circumferential side face of the cam body, and the grooves are continuously or intermittently distributed in the circumferential direction of the cam body; the length of the cam body in the axial direction is H, the width W of any groove in the axial direction of the cam body meets the condition that W / H is larger than or equal to 0.15 and smaller than or equal to 0.3, and after the cam is matched with the flexible bearing, buffer spaces capable of providing elastic deformation and absorbing vibration are formed in the grooves. According to the harmonic reducer, the cam with the groove and the width meeting the design range is designed and constructed in the peripheral side face, the balance weight of the cam is reduced, the contact area between the cam and the flexible bearing is reduced, in the operation process of the harmonic reducer, a buffer space for providing elastic deformation and absorbing vibration can be formed in the groove with a certain span in the axial direction, and the service life of the harmonic reducer is prolonged. Load distribution of the harmonic reducer in the operation process is more uniform, and high-speed, low-noise and small-vibration operation of the harmonic reducer is facilitated.

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, a circumferential side surface of the cam body is provided with grooves, and the grooves are continuously or discontinuously distributed along the circumference of the cam body; The cam body has an axial length of H, and the grooves are provided in a plurality of numbers, and the width W of any of the grooves in the axial direction of the cam body satisfies: 0.15≤W / H≤0.3, after the cam is matched with the flexible bearing, a buffer space is formed in the groove which can provide elastic deformation and absorb vibration.

[0007] Optionally, the groove includes a first groove and a second groove spaced apart along the axial direction of the cam body; The symmetry plane of the cam body perpendicular to the axis is a transverse symmetry plane, and the first groove and the second groove are respectively located on both sides of the transverse symmetry plane.

[0008] Optionally, the first groove is located on a first side of the transverse symmetry plane, and the second groove is located on a second side of the transverse symmetry plane; The projection distance between the first side end of the cam body and the first groove in the axial direction of the cam body is h1, the projection size of the first groove in the axial direction of the cam body is h2, the projection size of the second groove in the axial direction of the cam body is h3, and the projection distance between the second groove and the second side end of the cam body in the axial direction of the cam body is h4, wherein: h1=h4,h2=h3.

[0009] Optionally, the cam body has an axial length of H, and a projection distance between the first groove and the second groove in the axial direction of the cam body is h, wherein: H and h are positively correlated; H=h+2×(h1+h2), h and h1+h2 are negatively correlated.

[0010] Optionally, the cam body has an axial length of H, wherein: h1=h4=a×H, 0.1≤a≤0.25; h2=h3=b×H, 0.15≤b≤0.3.

[0011] Optionally, a takes a value of 0.16 and b takes a value of 0.2.

[0012] Optionally, the outer diameter of the major axis of the cam body is D, and the depth of the groove in the radial direction of the cam body is d1, wherein: d1=c×D, 0.00323≤c≤0.01613.

[0013] Optional, c takes the value 0.00968.

[0014] Optionally, the outer diameter of the major axis of the cam body is D, the depth of the groove in the radial direction of the cam body is d1, and the inner diameter of the major axis of the groove in the radial direction of the cam body is d, wherein: D = d + 2 × d1; D and d are positively correlated, and d and d1 are negatively correlated.

[0015] Optionally, the groove bottom and groove wall of the groove are connected through an arc surface transition.

[0016] A wave generator comprises a flexible bearing and any one of the above cams, wherein the flexible bearing is sleeved on the cam.

[0017] A harmonic reducer comprises a rigid wheel, a flexible wheel and the above-mentioned wave generator.

[0018] The cam provided in the present application is applied to a harmonic reducer, and includes a cam body, and grooves are provided on the circumferential side surfaces of the cam body, and the grooves are continuously or discontinuously distributed along the circumference of the cam body; the axial length of the cam body is H, and a plurality of grooves are provided, and the width W of any groove in the axial direction of the cam body satisfies: 0.15≤W / H≤0.3, and after the cam is matched with the flexible bearing, a buffer space that can provide elastic deformation and absorb vibration is formed in the groove. In this way, the circumferential side surface of the cam body is the surface of the cam used to cooperate with the flexible bearing, that is, the outer contour of the cam. There is a design with local material missing on the circumferential side surface of the cam body to form a groove. After many tests and verifications, the applicant found that the cam with a groove designed and constructed in the circumferential side surface and the groove width conforming to the above-mentioned design range not only reduces its own counterweight and reduces the contact area with the flexible bearing, so that the cam has better structural mechanical properties, but also during the operation of the harmonic reducer, a buffer space that provides elastic deformation and absorbs vibration can be formed in the groove with a certain span in the axial 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

[0019] 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.

[0020] Figure 1 A schematic diagram of the structure of the cam provided in an embodiment of the present application.

[0021] Figure 2 A schematic diagram of the cross-sectional structure of the cam provided in an embodiment of the present application.

[0022] Figure 3 for Figure 2 The dimension marking diagram at A in the middle.

[0023] exist Figure 1-Figure 3 middle: 1. Cam body; 101. First groove; 102. Second groove. DETAILED DESCRIPTION

[0024] 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.

[0025] 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.

[0026] like Figure 1-Figure 3 As shown, an embodiment of the present application provides a cam, which is applied to a harmonic reducer, including a cam body 1, and a groove is provided on the circumferential side surface of the cam body 1. The groove is continuously or discontinuously distributed along the circumference of the cam body 1, that is, the groove is a continuous area surrounded by the entire circumference or a non-continuous area distributed in multiple sections at intervals; the cam body 1 has an axial length of H, and a plurality of grooves are provided and the width (that is, the groove width) W of any groove in the axial direction of the cam body 1 satisfies: 0.15≤W / H≤0.3. After the cam is matched with the flexible bearing, a buffer space that can provide elastic deformation and absorb vibration is formed in the groove.

[0027] In this way, the circumferential side surface of the cam body 1 is the surface of the cam used to cooperate with the flexible bearing, that is, the outer contour of the cam. There is a design with local material missing on the circumferential side surface of the cam body 1, and a groove is formed. After many tests and verifications, the applicant found that the cam with a groove designed and constructed in the circumferential side surface and the groove width conforming to the above-mentioned design range not only reduces its own counterweight and reduces the contact area with the flexible bearing, so that the cam has better structural mechanical properties, but also during the operation of the harmonic reducer, a buffer space that provides elastic deformation and absorbs vibration can be formed in the groove with a certain span in the axial 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.

[0028] 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 harmonic reducers. It is found that grooves are opened on the circumferential side of the cam, and the groove width has a certain proportional range. This is a completely different material reduction design scheme from the past. Through 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, and outstanding technical effects are achieved through completely different design ideas.

[0029] 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.

[0030] In the present application, it is preferably designed that the grooves are continuously distributed on the peripheral side of the cam body 1 .

[0031] In addition, in some specific embodiments, when the grooves are designed to be intermittently distributed on the peripheral side of the cam body 1, both ends of each section of the groove are connected to the outer surface of the cam body 1 through a transition curved surface.

[0032] In addition, regarding the shape of the groove, it is preferable that the groove has a rectangular shape in a cross section where the axis of the cam body 1 is located.

[0033] It should be noted that there are many design situations for the number of grooves. Depending on the width of the groove, one, two, three, four, etc. can be set. It can be flexibly applied according to different working conditions of the cam.

[0034] Furthermore, in some specific embodiments, the groove includes a first groove 101 and a second groove 102 that are spaced apart along the axial direction of the cam body 1; the symmetry plane of the cam body 1 perpendicular to the axis is a transverse symmetry plane, and the first groove 101 and the second groove 102 are respectively located on both sides of the transverse symmetry plane. Figure 2 The lateral symmetry plane P is shown by way of example in FIG.

[0035] With such arrangement, according to different load sizes and working conditions on the inner and outer sides of the cam, the relationship between the first groove 101 and the second groove 102 is specifically divided into two situations: symmetrical arrangement and asymmetrical arrangement.

[0036] For the sake of easy distinction, the first side of the transverse symmetry plane and the first side of the cam body 1 are on the same side as the output side of the harmonic reducer, and the second side of the transverse symmetry plane and the second side of the cam body 1 are on the same side as the input side of the harmonic reducer. It can also be said that the first side of the transverse symmetry plane and the first side of the cam body 1 are the inner side, and the second side of the transverse symmetry plane and the second side of the cam body 1 are the outer side.

[0037] In some preferred embodiments, the first groove 101 is located on the first side of the transverse symmetry plane, and the second groove 102 is located on the second side of the transverse symmetry plane; the projection spacing between the first side end of the cam body 1 and the first groove 101 in the axial direction of the cam body 1 is h1, the projection dimension of the first groove 101 in the axial direction of the cam body 1 (that is, the groove width) is h2, the projection dimension of the second groove 102 in the axial direction of the cam body 1 (that is, the groove width) is h3, and the projection spacing between the second groove 102 and the second side end of the cam body 1 in the axial direction of the cam body 1 is h4, wherein: h1=h4, h2=h3.

[0038] In this way, the first groove 101 and the second groove 102 are symmetrical structures, that is, it is preferably designed that the first groove 101 and the second groove 102 have the same groove width, and the positions of the first groove 101 and the second groove 102 are symmetrically arranged about the transverse symmetry plane.

[0039] Similarly, when h1≠h4 and h2≠h3, the first groove 101 and the second groove 102 are asymmetric structures.

[0040] 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.

[0041] In some specific embodiments, the axial length of the cam body 1 is H, and the projection spacing between the first groove 101 and the second groove 102 on the axial direction of the cam body 1 is h, wherein: H and h are positively correlated, that is, the larger H is, the larger the design value of h is; H=h+2×(h1+h2), h and h1+h2 are negatively correlated, that is, the larger h is, the smaller the design value of h1+h2 is. Since H=h+h1+h2+h3+h4, under the premise of h1=h4 and h2=h3, H=h+2×(h1+h2).

[0042] Furthermore, the axial length of the cam body 1 is H, wherein: h1=h4=a×H, 0.1≤a≤0.25; h2=h3=b×H, 0.15≤b≤0.3.

[0043] With such a configuration, after testing and verification, when the first groove 101 and the second groove 102 are symmetrical structures, the cam designed according to the above-mentioned ratio range can ensure that after the cam is assembled in the harmonic reducer, the uniformity of load distribution of the harmonic reducer during operation is improved.

[0044] Exemplarily, the value of a is 0.16 and the value of b is 0.2.

[0045] In some other specific embodiments, the outer diameter of the major axis of the cam body 1 is D, and the depth of the groove in the radial direction of the cam body 1 (i.e., the groove depth) is d1, wherein: d1=c×D, 0.00323≤c≤0.01613. In the case where the groove includes the first groove 101 and the second groove 102, the groove depths of the first groove 101 and the second groove 102 can be set to be the same. With such a setting, after testing and verification, the cam designed according to the above-mentioned ratio range can 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.

[0046] Exemplarily, the value of c is 0.00968.

[0047] Since the outer contour of the cam body 1 is elliptical, in some other specific embodiments, the outer diameter of the major axis of the cam body 1 is D, the depth of the groove in the radial direction of the cam body 1 is d1, and the inner diameter of the major axis of the groove in the radial direction of the cam body 1 is d, wherein: D=d+2×d1; D and d are positively correlated, that is, the larger the value of D, the larger the value of d, and d and d1 are negatively correlated, that is, the larger the value of d, the smaller the value of d1. In the case where the groove includes the first groove 101 and the second groove 102, the depth of the first groove 101 and the second groove 102 in the radial direction of the cam body 1 can be set to be the same. In this way, the radial size of the ellipse surrounded by the groove bottom of the groove should be adaptively designed to follow the radial size of the cam body 1 to ensure the volume of the entity part of the cam body 1, which is conducive to ensuring the structural strength of the cam body 1 as the design basis.

[0048] In some other preferred embodiments, the groove bottom and the groove wall of the groove are transitionally connected through an arc surface R. In this way, the groove bottom of the groove has a rounded corner design, which is beneficial to avoid stress concentration and optimize the mechanical properties and structural strength of the cam.

[0049] In addition, the edges of the cam body 1 may be chamfered and deburred to facilitate installation and removal of the cam in the harmonic reducer.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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 a groove is provided on a circumferential side surface of the cam body (1), and the groove is continuously or discontinuously distributed along the circumference of the cam body (1); The cam body (1) has an axial length of H, a plurality of grooves are provided, and the width W of any of the grooves in the axial direction of the cam body (1) satisfies: 0.15≤W / H≤0.3, after the cam is matched with the flexible bearing, a buffer space capable of providing elastic deformation and absorbing vibration is formed in the groove.

2. The cam according to claim 1, characterized in that: The groove comprises a first groove (101) and a second groove (102) which are spaced apart along the axial direction of the cam body (1); The symmetry plane of the cam body (1) perpendicular to the axis is a transverse symmetry plane, and the first groove (101) and the second groove (102) are respectively located on both sides of the transverse symmetry plane.

3. The cam according to claim 2, characterized in that: The first groove (101) is located on a first side of the transverse symmetry plane, and the second groove (102) is located on a second side of the transverse symmetry plane; The projection distance between the first side end of the cam body (1) and the first groove (101) in the axial direction of the cam body (1) is h1, the projection dimension of the first groove (101) in the axial direction of the cam body (1) is h2, the projection dimension of the second groove (102) in the axial direction of the cam body (1) is h3, and the projection distance between the second groove (102) and the second side end of the cam body (1) in the axial direction of the cam body (1) is h4, wherein: h1=h4,h2=h3.

4. The cam according to claim 3, characterized in that: The cam body (1) has an axial length of H, and a projection distance between the first groove (101) and the second groove (102) in the axial direction of the cam body (1) is h, wherein: H and h are positively correlated; H=h+2×(h1+h2), h and h1+h2 are negatively correlated.

5. The cam according to claim 3 or 4, characterized in that: The cam body (1) has an axial length of H, wherein: h1=h4=a×H, 0.1≤a≤0.25; h2=h3=b×H, 0.15≤b≤0.

3.

6. The cam according to claim 5, characterized in that: The value of a is 0.16 and the value of b is 0.

2.

7. The cam according to claim 1, characterized in that: The outer diameter of the major axis of the cam body (1) is D, and the depth of the groove in the radial direction of the cam body (1) is d1, wherein: d1=c×D, 0.00323≤c≤0.01613.

8. The cam according to claim 7, characterized in that: The value of c is 0.00968.

9. The cam according to claim 1, characterized in that: The outer diameter of the major axis of the cam body (1) is D, the depth of the groove in the radial direction of the cam body (1) is d1, and the inner diameter of the major axis of the groove in the radial direction of the cam body (1) is d, wherein: D = d + 2 × d1; D and d are positively correlated, and d and d1 are negatively correlated.

10. The cam according to claim 1, characterized in that: The groove bottom and the groove wall of the groove are connected through an arc surface transition.

11. A wave generator, characterized in that: It comprises a flexible bearing and a cam as described in any one of claims 1 to 10, wherein the flexible bearing is sleeved on the cam.

12. A harmonic reducer, characterized in that: It comprises a rigid wheel, a flexible wheel and the wave generator as claimed in claim 11.

Images