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 end face of the cam body, the grooves comprise first grooves and second grooves which are distributed in the end faces of the two sides of the cam body respectively, the first grooves are continuously or intermittently distributed around the axis of the cam body, and the second grooves are continuously or intermittently distributed around the axis of the cam body. The second grooves are continuously or discontinuously distributed around the axis of the cam body; the length of the cam body in the axial direction is H, the depth of the first groove in the axial direction of the cam body is h1, the depth of the second groove in the axial direction of the cam body is h2, h1 = a * H, 0.1 < = a < = 0.35, h2 = b * H, 0.1 < = b < = 0.35, and after the cam is matched with the flexible bearing, a buffer space capable of providing elastic deformation and absorbing vibration is formed in the first groove and the second groove. The self weight is reduced, the load distribution of the harmonic reducer in the operation process is more uniform, and high-speed, low-noise and small-vibration operation 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, an end surface of the cam body is provided with a groove, the groove comprises a first groove and a second groove respectively distributed on both side end surfaces of the cam body, the first groove is continuously or discontinuously distributed around the axis of the cam body, and the second groove is continuously or discontinuously distributed around the axis of the cam body; The cam body has an axial length of H, the first groove has an axial depth of h1, and the second groove has an axial depth of h2, wherein: h1=a×H, 0.1≤a≤0.35, h2=b×H, 0.1≤b≤0.35. After the cam is matched with the flexible bearing, a buffer space that can provide elastic deformation and absorb vibration is formed in the first groove and the second groove.

[0007] Optionally, 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+h1+h2, h and h1+h2 are negatively correlated.

[0008] Optionally, the outer diameter of the major axis of the cam body is D, and on the radial major axis of the cam body, the distance between the first groove and the outer edge of the cam body is d1, and the distance between the second groove and the outer edge of the cam body is d2, wherein: d1=m×D, 0.0564≤m≤0.0731; d2=n×D, 0.0564≤n≤0.0731.

[0009] Optionally, the width of the first groove in the radial direction of the cam body is w1, and the width of the second groove in the radial direction of the cam body is w2, wherein: 0.5mm≤w1≤2mm, 0.5mm≤w2≤2mm.

[0010] Optionally, the outer diameter of the major axis of the cam body is D, the outer diameter of the first groove is D1, the inner diameter of the first groove is d, the width of the first groove in the radial direction of the cam body is w1, and the distance between the first groove and the outer edge of the cam body on the radial major axis of the cam body is d1, wherein: D = D1 + 2 × d1, D1 = d + 2 × w1; D and D1 are positively correlated, and D1 and d1 are negatively correlated; There is a positive correlation between D1 and d, and a negative correlation between d and w1.

[0011] Optionally, a symmetry plane of the cam body perpendicular to the axis is a transverse symmetry plane, and the first groove and the second groove are symmetrically arranged with respect to the transverse symmetry plane.

[0012] Optionally, a takes a value of 0.24 and b takes a value of 0.24.

[0013] Optionally, m is 0.06452 and n is 0.06452.

[0014] Optionally, the value of w1 is 1.2 mm and the value of w2 is 1.2 mm.

[0015] Optionally, both the first groove and the second groove are annular grooves.

[0016] Optionally, the groove bottom and the groove wall of the groove are connected by an arc surface transition, and the radius of the arc surface is R, 0.1mm≤R≤0.3mm.

[0017] Optionally, the notch of the groove is provided with a chamfer, and the size of the chamfer is C, 0.1mm≤C≤0.5mm.

[0018] A wave generator comprises a flexible bearing and any one of the above cams, wherein the flexible bearing is sleeved on the cam.

[0019] A harmonic reducer comprises a rigid wheel, a flexible wheel and the above-mentioned wave generator.

[0020] The cam provided in the present application is applied to a harmonic reducer, and includes a cam body. A groove is formed on the end face of the cam body. The groove includes a first groove and a second groove respectively distributed on the end faces of both sides of the cam body. The first groove is continuously or discontinuously distributed around the axis of the cam body, and the second groove is continuously or discontinuously distributed around the axis of the cam body. The axial length of the cam body is H, the axial depth of the first groove of the cam body is h1, and the axial depth of the second groove of the cam body is h2, wherein: h1=a×H, 0.1≤a≤0.35, h2=b×H, 0.1≤b≤0.35, 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 first groove and the second groove. With such arrangement, there is a design with local material missing on the end face of the cam body, forming a groove. After many tests and verifications, the applicant found that the cam designed and constructed with grooves in the end faces on both sides and the groove depth meets the above-mentioned design range, not only reduces its own counterweight, but also the I-shaped structure presented in the cross section makes the cam have better structural mechanical properties. Moreover, 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 radial 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 cams 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

[0021] 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.

[0022] Figure 1 A schematic diagram of the structure of the cam provided in an embodiment of the present application.

[0023] Figure 2 This is a front view of the cam provided in an embodiment of the present application.

[0024] Figure 3 A schematic diagram of the cross-sectional structure of the cam provided in an embodiment of the present application.

[0025] Figure 4 for Figure 3 Partial schematic diagram at point A in the middle.

[0026] exist Figure 1-Figure 4 middle: 1. Cam body; 101. First groove; 102. Second groove. DETAILED DESCRIPTION

[0027] 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.

[0028] 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.

[0029] like Figure 1-Figure 4 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 opened on the end surface of the cam body 1. The groove includes a first groove 101 and a second groove 102 respectively distributed on the end surfaces of both sides of the cam body 1, the first groove 101 is continuously or discontinuously distributed around the axis of the cam body 1, and the second groove 102 is continuously or discontinuously distributed around the axis of the cam body 1, that is, the groove is a continuous area surrounded by the whole circumference or a non-continuous area distributed in multiple sections; the axial length of the cam body 1 is H, the depth of the first groove 101 in the axial direction of the cam body 1 (that is, the groove depth) is h1, and the depth of the second groove 102 in the axial direction of the cam body 1 (that is, the groove depth) is h2, wherein: h1=a×H, 0.1≤a≤0.35, h2=b×H, 0.1≤b≤0.35, after the cam is matched with the flexible bearing, a buffer space that can provide elastic deformation and absorb vibration is formed in the first groove 101 and the second groove 102. The end faces of the cam body 1 are two faces that are opposite to each other in the axial direction; a and b may have the same value or different values.

[0030] With such arrangement, there is a design in which there is a local material missing on the end face of the cam body 1, and a groove is formed. After many tests and verifications, the applicant found that a cam with grooves designed and constructed in the end faces on both sides and the groove depth conforming to the above-mentioned design range not only reduces its own counterweight, but also the I-shaped structure presented in the cross section makes the cam have better structural mechanical properties. Moreover, 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 radial 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 cams 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.

[0031] 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 of harmonic reducer performance. It is found that grooves are opened on the end faces of both sides of the cam, and the groove depth 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. Outstanding technical effects have been achieved through completely different design ideas.

[0032] 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.

[0033] In the present application, it is preferably designed that the grooves are continuously distributed on the end surface of the cam body 1 throughout the entire circumference.

[0034] In addition, in some specific embodiments, when the grooves are designed to be intermittently distributed on the end surface 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.

[0035] In addition, regarding the shape of the groove, in the cross section where the axis of the cam body 1 is located, the groove is preferably rectangular; preferably, the first groove 101 and the second groove 102 are both annular grooves, that is, the first groove 101 and the second groove 102 are not designed to follow the elliptical shape of the cam.

[0036] Exemplarily, the value of a is 0.24, and the value of b is 0.24.

[0037] 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.

[0038] In some specific embodiments, the projection spacing 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, that is, the larger H is, the larger the design value of h is; H=h+h1+h2, h and h1+h2 are negatively correlated, that is, the larger h is, the smaller the design value of h1+h2 is.

[0039] With such arrangement, the axial spacing between the first groove 101 and the second groove 102 should be adaptively designed to follow the axial size of the cam body 1 to ensure the volume of the solid part of the cam body 1, which is conducive to ensuring the structural strength of the cam body 1 as the design basis.

[0040] In some specific embodiments, the outer diameter of the major axis of the cam body 1 is D, and on the radial major axis of the cam body 1, the spacing between the first groove 101 and the outer edge of the cam body 1 is d1, and the spacing between the second groove 102 and the outer edge of the cam body 1 is d2, wherein: d1=m×D, 0.0564≤m≤0.0731; d2=n×D, 0.0564≤n≤0.0731. m and n can be the same value or different values.

[0041] 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 load distribution of the harmonic reducer during operation is improved.

[0042] Exemplarily, the value of m is 0.06452, and the value of n is 0.06452.

[0043] In some other specific embodiments, the width of the first groove 101 in the radial direction of the cam body 1 (ie, the groove width) is w1, and the width of the second groove 102 in the radial direction of the cam body 1 (ie, the groove width) is w2, wherein: 0.5mm≤w1≤2mm, 0.5mm≤w2≤2mm.

[0044] 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 load distribution of the harmonic reducer during operation is improved.

[0045] Exemplarily, the value of w1 is 1.2 mm, and the value of w2 is 1.2 mm.

[0046] In some other specific embodiments, the outer diameter of the long axis of the cam body 1 is D, the outer diameter of the first groove 101 is D1, the inner diameter of the first groove 101 is d, the width of the first groove 101 in the radial direction of the cam body 1 (that is, the groove width) is w1, and on the radial long axis of the cam body 1, the spacing between the first groove 101 and the outer edge of the cam body 1 is d1, wherein: D=D1+2×d1, D1=d+2×w1; D and D1 are positively correlated, and D1 and d1 are negatively correlated; D1 and d are positively correlated, and d and w1 are negatively correlated. In this way, the outer diameter D1 and the inner diameter d of the first groove 101 can be determined first by the basic parameter of the outer diameter D of the long axis of the cam body 1, so as to obtain the groove width w1 of the first groove 101 and the spacing d1 between the first groove 101 and the outer edge of the cam body 1. Following this design idea is conducive to reasonably and quickly completing the overall parameter design of the cam. The second groove 102 is similar.

[0047] According to the load size and working conditions of the inner and outer sides of the cam, the first groove 101 and the second groove 102 can be designed with a symmetrical structure or an asymmetrical structure. For the sake of 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.

[0048] In some preferred embodiments, 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 symmetrically arranged about the transverse symmetry plane, that is, h1=h2, d1=d1´. In this way, the first groove 101 and the second groove 102 are completely symmetrically arranged, and the best effect is achieved among the values ​​that can be explored and obtained. Figure 3 The lateral symmetry plane O is shown as an example in FIG.

[0049] If the first groove 101 and the second groove 102 are asymmetric structures, then h1≠h2, d1≠d2.

[0050] In some optional embodiments, the groove bottom and the groove wall of the groove are connected by an arc surface transition, and the radius of the arc surface is R, 0.1mm≤R≤0.3mm. In this way, the groove bottom of the groove has a rounded corner design, which is conducive to avoiding stress concentration and optimizing the mechanical properties and structural strength of the cam. The preferred value of R is 0.2mm.

[0051] In some optional embodiments, the notch of the groove is provided with a chamfer, the size of the chamfer is C, 0.1mm≤C≤0.5mm, and C is preferably 0.3mm.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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: The invention is applied to a harmonic reducer, comprising a cam body (1), wherein an end surface of the cam body (1) is provided with a groove, wherein the groove comprises a first groove (101) and a second groove (102) respectively distributed on both side end surfaces of the cam body (1), wherein the first groove (101) is continuously or discontinuously distributed around the axis of the cam body (1), and the second groove (102) is continuously or discontinuously distributed around the axis of the cam body (1); The cam body (1) has an axial length of H, the first groove (101) has an axial depth of h1, and the second groove (102) has an axial depth of h2, wherein: h1=a×H, 0.1≤a≤0.35, h2=b×H, 0.1≤b≤0.35, after the cam is matched with the flexible bearing, a buffer space capable of providing elastic deformation and absorbing vibration is formed in the first groove (101) and the second groove (102).

2. The cam according to claim 1, characterized in that: The 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+h1+h2, h and h1+h2 are negatively correlated.

3. The cam according to claim 1, characterized in that: The outer diameter of the major axis of the cam body (1) is D, and on the radial major axis of the cam body (1), the distance between the first groove (101) and the outer edge of the cam body (1) is d1, and the distance between the second groove (102) and the outer edge of the cam body (1) is d2, wherein: d1=m×D, 0.0564≤m≤0.0731; d2=n×D, 0.0564≤n≤0.0731.

4. The cam according to claim 1, characterized in that: The width of the first groove (101) in the radial direction of the cam body (1) is w1, and the width of the second groove (102) in the radial direction of the cam body (1) is w2, wherein: 0.5mm≤w1≤2mm, 0.5mm≤w2≤2mm.

5. The cam according to claim 1, characterized in that: The outer diameter of the major axis of the cam body (1) is D, the outer diameter of the first groove (101) is D1, the inner diameter of the first groove (101) is d, the width of the first groove (101) in the radial direction of the cam body (1) is w1, and on the radial major axis of the cam body (1), the distance between the first groove (101) and the outer edge of the cam body (1) is d1, wherein: D = D1 + 2 × d1, D1 = d + 2 × w1; D and D1 are positively correlated, and D1 and d1 are negatively correlated; There is a positive correlation between D1 and d, and a negative correlation between d and w1.

6. The cam according to any one of claims 1 to 5, characterized in that: 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 symmetrically arranged with respect to the transverse symmetry plane.

7. The cam according to claim 1, characterized in that: The value of a is 0.24 and the value of b is 0.

24.

8. The cam according to claim 3, characterized in that: The value of m is 0.06452, and the value of n is 0.06452.

9. The cam according to claim 4, characterized in that: The value of w1 is 1.2mm, and the value of w2 is 1.2mm.

10. The cam according to claim 1, characterized in that: The first groove (101) and the second groove (102) are both annular grooves.

11. 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, and the radius of the arc surface is R, 0.1mm≤R≤0.3mm.

12. The cam according to claim 1, characterized in that: The notch of the groove is provided with a chamfer, and the size of the chamfer is C, 0.1mm≤C≤0.5mm.

13. A wave generator, characterized in that: It comprises a flexible bearing and a cam as described in any one of claims 1 to 12, wherein the flexible bearing is sleeved on the cam.

14. A harmonic reducer, characterized in that: It comprises a rigid wheel, a flexible wheel and the wave generator as claimed in claim 13.

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