Wave generator, harmonic reducer and robot

Abstract

The utility model discloses a wave generator, harmonic reducer and robot, relate to harmonic reducer technical field, and the wave generator includes cam and flexible bearing, and the one -end surface of cam has recess along the axial direction of cam, and recess sets up along the circumference direction of cam, flexible bearing is set to cam outside, and flexible bearing and cam interference fit to make the slot mouth of recess reduce, and make the outer peripheral wall of flexible bearing outer ring set up along the opening direction of recess to cam's axis inclination, according to the wave generator of the utility model embodiment, is used for and flexible wheel cooperation, and can improve the service life of flexible wheel.

Description

Technical Field

[0001] This utility model relates to the field of harmonic reducer technology, and in particular to a wave generator, a harmonic reducer and a robot. Background Technology

[0002] In the assembly of harmonic reducers, the wave generator and the flex wheel need to be interference-fitted. At this time, the gear section of the flex wheel is deformed outward in a trumpet shape. Since the wave generator as a whole has great rigidity in the radial direction, it is in line contact with the inner wall of the flex wheel. The flex wheel will experience stress concentration, which can easily cause cracking or breakage, thus reducing the service life of the flex wheel. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a wave generator for use with a flexspline, which can improve the service life of the flexspline.

[0004] This utility model also proposes a harmonic reducer and a robot having the above-mentioned wave generator.

[0005] The wave generator according to an embodiment of the present invention includes a cam and a flexible bearing. The cam has a groove on one end face along the axial direction of the cam. The groove is annular. The cam has an elastic portion located on the radially outer side of the groove. The flexible bearing is sleeved on the cam and is interference-fitted with the cam so that the elastic portion elastically deforms toward the groove. Along the opening direction toward the groove, the outer peripheral wall of the flexible bearing is inclined toward the axis of the cam.

[0006] The wave generator according to the embodiments of this utility model has at least the following beneficial effects: Since the cam has a groove on one end face along its axial direction, and the groove is annular, the cam has an elastic portion located radially outward from the groove. A flexible bearing is sleeved on the outside of the cam, and the flexible bearing is interference-fitted with the cam so that the elastic portion undergoes elastic deformation towards the groove. Along the opening direction towards the groove, the outer peripheral wall of the flexible bearing is inclined towards the axis of the cam. Therefore, when the wave generator is installed and fitted with the flexible wheel, the gear segment of the flexible wheel expands and deforms outward, matching the inclined direction of the outer peripheral wall of the flexible bearing. Thus, the outer peripheral wall of the flexible bearing fits against the inner wall of the outwardly deformed gear segment, and the two are in surface contact, reducing stress concentration between the wave generator and the flexible wheel and improving the service life of the flexible wheel.

[0007] According to one embodiment of the present invention, when the elastic part is in a free state, the groove on the longitudinal section of the cam is rectangular, triangular or trapezoidal.

[0008] According to one embodiment of the present invention, the axial length of the cam is L0, the elastic part is in a free state, and the maximum depth of the groove along the axial direction of the cam is L, satisfying: L≤(L0-5mm).

[0009] According to one embodiment of the present invention, the cam has an inner hole, the distance from the side wall of the inner hole to the outer peripheral wall of the cam is H, the elastic part is in a free state, and the maximum width of the groove along the radial direction of the cam is h, satisfying: 2mm≤h≤(H-4mm).

[0010] According to one embodiment of the present invention, when the elastic part is in a free state, the minimum distance from the groove along the radial direction of the cam to the outer peripheral wall of the cam is b, which satisfies: b≥2mm.

[0011] According to one embodiment of the present invention, the groove includes a first groove portion and a second groove portion, the first groove portion having the opening, the second groove portion being connected to the end of the first groove portion away from the opening, the elastic portion being in a free state, and along the radial direction of the cam, the maximum width of the second groove portion being greater than the maximum width of the first groove portion.

[0012] According to one embodiment of the present invention, when the elastic part is in a free state, the thickness of the elastic part is equal along the circumferential direction of the cam in any cross-section of the cam.

[0013] According to one embodiment of the present invention, the groove in the cross-section of the cam is elliptical.

[0014] According to an embodiment of the present invention, a harmonic reducer includes a flexible wheel, a rigid wheel, and a wave generator of the present invention. The outer peripheral wall of the flexible bearing is interference-fitted with the inner wall of the flexible wheel. The opening of the groove faces away from the gear segment port of the flexible wheel. The flexible wheel meshes with the rigid wheel.

[0015] The harmonic reducer according to the embodiments of this utility model has at least the following beneficial effects: Since the wave generator can improve the service life of the flexure, and simultaneously, when the outer peripheral wall of the flexible bearing outer ring is in surface contact with the inner wall of the gear segment, the outward expansion angle of the gear segment decreases, and the effective meshing tooth width between the flexure and the rigid wheel increases, further improving the service life of the flexure. Overall, the service life of the harmonic reducer is also improved.

[0016] The robot according to an embodiment of the present invention includes the harmonic reducer of the present invention.

[0017] The robot according to the embodiments of this utility model has at least the following beneficial effects: since the service life of the harmonic reducer is improved, the service life of the robot is also improved, which better meets the needs of customers.

[0018] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0020] Figure 1 This is a cross-sectional view of the cam of a wave generator according to an embodiment of the present invention;

[0021] Figure 2 This is a cross-sectional view of the cam of the wave generator according to another embodiment of the present invention;

[0022] Figure 3 This is a cross-sectional view of the cam of the wave generator according to another embodiment of the present invention;

[0023] Figure 4 This is a cross-sectional view of the cam of the wave generator according to another embodiment of the present invention;

[0024] Figure 5 This is a cross-sectional view of a harmonic reducer according to an embodiment of the present invention;

[0025] Figure 6 for Figure 5 Enlarged view of point B in the middle.

[0026] Figure label:

[0027] Harmonic reducer 1000;

[0028] Wave generator 100; Cam 110; Groove 111; First groove 1111; Second groove 1112; Elastic part 112; Inner hole 113; Flexible bearing 120;

[0029] Flexible wheel 200; gear section 210; transition section 220; flange section 230. Detailed Implementation

[0030] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0031] In the description of this utility model, it should be understood that the orientation descriptions, such as up, down, inside, outside, etc., are based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0032] In the description of this utility model, the use of "first" and "second" is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features or the order of the technical features.

[0033] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0034] Harmonic reducers possess unique advantages such as high load capacity, large transmission ratio, small size, light weight, smooth transmission, and high transmission accuracy, and are widely used in fields such as industrial robots. A harmonic reducer typically consists of a wave generator, a flex wheel, and a rigid wheel. During assembly, the wave generator and flex wheel need to be interference-fitted, and the gear section of the flex wheel needs to mesh with the internal teeth of the rigid wheel.

[0035] In the interference fit between the wave generator and the flexure, the wave generator's high radial stiffness results in line contact between it and the inner wall of the flexure. This leads to an excessively large outward expansion angle of the flexure, causing stress concentration and making it prone to cracking or breakage, thus reducing its service life. Furthermore, the excessive outward expansion angle results in a smaller effective meshing tooth width when the flexure's gear section meshes with the rigid wheel's internal teeth, increasing the stress between them and further affecting the flexure's service life. Clearly, the flexure's service life affects the harmonic reducer's service life, and further, the service life of industrial robots.

[0036] Therefore, one embodiment of this utility model provides a wave generator 100, as detailed in the accompanying drawings. Figures 1 to 6 As shown.

[0037] Reference Figure 1As shown, a wave generator 100 according to an embodiment of the present invention includes a cam 110. The cam 110 has a groove 111 located on one end face of the cam 110 along its axial direction. It should be noted that the groove 111 can be located on any end face of the cam 110 along its axial direction; that is, the end face of the cam 110 where the groove 111 is located is not specifically limited here. It should be noted that the groove 111 is annular. It can be understood that the cam 110 is actually an elliptical cylindrical structure, that is, the cam 110 is cylindrical, and the cross-section of the cam 110 is elliptical. The cross-section refers to the surface perpendicular to the axial direction of the cam 110. Obviously, the annular shape of the groove 111 is actually to match the specific structure of the cam 110. In one embodiment, the groove 111 is an elliptical annular shape on the cross-section of the cam 110, thereby better matching the specific structure of the cam 110.

[0038] Continue to refer to Figure 1 As shown, the cam 110 is provided with an elastic portion 112, which is located radially outward of the groove 111 along the cam 110. In fact, the elastic portion 112 is one of the structures defining the groove 111; that is, the elastic portion 112 and the cam 110 jointly define the groove 111. It should be noted that the elastic portion 112 can be understood as a cantilever structure, and the elastic element can undergo elastic deformation. In this embodiment of the invention, the free state of the elastic portion 112 should be understood as the state when the elastic portion 112 has not undergone elastic deformation, such as the state when the cam 110 is not assembled with the flexible bearing 120, or the state after the cam 110 has been disassembled from the flexible bearing 120. The state after the elastic portion 112 undergoes elastic deformation is called the deformed state. When the elastic portion 112 is in the free state, the elastic portion 112 extends axially along the cam 110. It should be noted that the elastic part 112 and the cam 110 are an integral structure. Therefore, when the elastic part 112 undergoes elastic deformation, it is not easy for it to break and detach from the cam 110 at the connection point.

[0039] In one embodiment, the elastic portion 112 is in a free state, and the thickness of the elastic portion 112 is equal along the circumferential direction of the cam 110 at any cross-section of the cam 110. According to the above arrangement, if subjected to the same magnitude of radial force along the cam 110, the elastic deformation of the elastic portion 112 at any position along the circumferential direction of the cam 110 will be the same.

[0040] Reference Figure 1As shown, in one embodiment of the wave generator 100 of this utility model, the longitudinal section refers to the section along the axial direction of the cam 110. When the elastic part 112 is in a free state, the groove 111 on the longitudinal section of the cam 110 is rectangular. One side of the rectangle corresponds to the opening of the groove 111. In one embodiment, the rectangle is a long rectangle, comprising two long sides of equal length and two short sides of equal length. One of the long sides of the rectangle corresponds to the outline of the elastic part 112, and one of the short sides of the rectangle corresponds to the opening of the groove 111. At this time, the thickness of the elastic part 112 is uniform along the axial direction of the cam 110.

[0041] Reference Figure 1 As shown, it should be noted that the axial length of the cam 110 is L0, the elastic part 112 is in a free state, and the maximum depth of the groove 111 along the axial direction of the cam 110 is L, satisfying: L≤(L0-5mm). It should be noted that in this embodiment, L is the length of the two longer sides. Additionally, the cam 110 has an inner hole 113, which connects the two end faces of the cam 110 along its axial direction. The distance from the sidewall of the inner hole 113 to the outer peripheral wall of the cam 110 is H. It should be noted that the size of the inner hole 113 is not specifically limited here. It should be noted that the cross-section of the inner hole 113 is elliptical. It should be noted that when the elastic part 112 is in a free state, the maximum width of the groove 111 along the radial direction of the cam 110 to the outer peripheral wall of the cam 110 is h, satisfying: 2mm≤h≤(H-4mm). It should be noted that in this embodiment, h is the distance between the two longer sides, i.e., h is the length of the shorter side. Furthermore, when the elastic part 112 is in a free state, the minimum distance from the groove 111 along the radial direction of the cam 110 to the outer peripheral wall of the cam 110 is b, satisfying: b ≥ 2 mm. It should be noted that in this embodiment, b is the distance from the long side of the contour line of the elastic part 112 to the outer peripheral wall of the cam 110. In this embodiment, b can be understood as the thickness of the elastic part 112 along the radial direction of the cam 110. It should be noted that the aforementioned ranges of L, h, and b enable a more reasonable structure for the groove 111, allowing the elastic part 112 to undergo better elastic deformation. In another embodiment, the rectangle is a square, with one side of the square corresponding to the contour line of the elastic part 112 and another side corresponding to the opening of the groove 111. In this case, the thickness of the elastic part 112 is uniform along the axial direction of the cam 110. In another embodiment, the rectangle is a long rectangle, with one short side corresponding to the contour line of the elastic part 112 and one long side corresponding to the opening of the groove 111. At this time, the thickness of the elastic part 112 is uniform along the axial direction of the cam 110.

[0042] Reference Figure 2As shown, in another embodiment, the elastic part 112 is in a free state, and the groove 111 is triangular in the longitudinal section of the cam 110. One side of the triangle corresponds to the opening of the groove 111. In one embodiment, the triangle is an isosceles triangle, consisting of two long sides of equal length and one short side. One long side of the isosceles triangle corresponds to the outline of the elastic part 112, and the short side of the isosceles triangle corresponds to the opening of the groove 111. At this time, the thickness of the elastic part 112 gradually decreases along the axial direction of the cam 110.

[0043] Reference Figure 2 As shown, it should be noted that the axial length of the cam 110 is L0, the elastic part 112 is in a free state, and the maximum depth of the groove 111 along the axial direction of the cam 110 is L, satisfying: L≤(L0-5mm). It should be noted that in this embodiment, L is the distance from the intersection of the two long sides to the short side. Additionally, the cam 110 has an inner hole 113, which connects the two end faces of the cam 110 along its axial direction. The distance from the sidewall of the inner hole 113 to the outer peripheral wall of the cam 110 is H. It should be noted that the size of the inner hole 113 is not specifically limited here. It should be noted that the cross-section of the inner hole 113 is elliptical. It should be noted that when the elastic part 112 is in a free state, the maximum width of the groove 111 along the radial direction of the cam 110 to the outer peripheral wall of the cam 110 is h, satisfying: 2mm≤h≤(H-4mm). It should be noted that in this embodiment, h is the distance between the two intersection points of the short side and the two long sides, i.e., h is the length of the short side. Furthermore, when the elastic part 112 is in a free state, the minimum distance from the groove 111 along the radial direction of the cam 110 to the outer peripheral wall of the cam 110 is b, satisfying: b ≥ 2 mm. It should be noted that in this embodiment, b is the minimum distance from the long side of the contour line of the elastic part 112 to the outer peripheral wall of the cam 110. In this embodiment, b can be understood as the distance from the intersection point of the long and short sides of the contour line of the elastic part 112 to the outer peripheral wall of the cam 110. It should be noted that the above-mentioned ranges of L, h, and b enable a more reasonable structure for the groove 111, allowing the elastic part 112 to undergo better elastic deformation. In another embodiment, the triangle is an equilateral triangle, with one side of the equilateral triangle corresponding to the contour line of the elastic part 112, and the other side of the equilateral triangle corresponding to the opening of the groove 111. At this point, the thickness of the elastic portion 112 gradually decreases along the axial direction of the cam 110. In another embodiment, the triangle is an scalene triangle, and the angles of all three angles of the triangle are less than 90 degrees. One side of the scalene triangle corresponds to the outline of the elastic portion 112, and the other side of the scalene triangle corresponds to the opening of the groove 111. At this point, the thickness of the elastic portion 112 gradually decreases along the axial direction of the cam 110.

[0044] Reference Figure 3 As shown, in another embodiment, the elastic portion 112 is in a free state, and the groove 111 is trapezoidal in the longitudinal section of the cam 110. The trapezoid includes two parallel sides and two inclined sides, one of which corresponds to the opening of the groove 111. In one embodiment, one inclined side corresponds to the outline of the elastic portion 112, and the shorter parallel side corresponds to the opening of the groove 111. In this case, the thickness of the elastic portion 112 gradually increases along the axial direction of the cam 110. It should be noted that the shape of the groove 111 is not specifically limited in the longitudinal section of the cam 110.

[0045] Reference Figure 3 As shown, it should be noted that the axial length of the cam 110 is L0, the elastic part 112 is in a free state, and the maximum depth of the groove 111 along the axial direction of the cam 110 is L, satisfying: L≤(L0-5mm). It should be noted that in this embodiment, L is the distance between the two parallel sides. Additionally, the cam 110 has an inner hole 113, which connects the two end faces of the cam 110 along its axial direction. The distance from the sidewall of the inner hole 113 to the outer peripheral wall of the cam 110 is H. It should be noted that the size of the inner hole 113 is not specifically limited here. It should be noted that the cross-section of the inner hole 113 is elliptical. It should be noted that when the elastic part 112 is in a free state, the maximum width of the groove 111 along the radial direction of the cam 110 to the outer peripheral wall of the cam 110 is h, satisfying: 2mm≤h≤(H-4mm). It should be noted that in this embodiment, h is the distance between the two intersection points of the longer parallel side and the two inclined sides, that is, h is the length of the longer parallel side. Furthermore, when the elastic part 112 is in a free state, the minimum distance from the groove 111 along the radial direction of the cam 110 to the outer peripheral wall of the cam 110 is b, satisfying: b ≥ 2 mm. It should be noted that in this embodiment, b is the minimum distance from the inclined side of the contour line of the elastic part 112 to the outer peripheral wall of the cam 110. In this embodiment, b can be understood as the distance from the intersection point of the inclined side of the contour line of the elastic part 112 and the longer parallel side to the outer peripheral wall of the cam 110. It should be noted that the above-mentioned ranges of L, h, and b enable a more reasonable structure for the groove 111, allowing the elastic part 112 to undergo better elastic deformation. In another embodiment, one inclined side corresponds to the contour line of the elastic part 112, and the longer parallel side corresponds to the opening of the groove 111. In this case, the thickness of the elastic part 112 gradually decreases along the axial direction of the cam 110.

[0046] Reference Figure 4As shown, in one embodiment of the wave generator 100 of this utility model, the groove 111 includes a first groove portion 1111 and a second groove portion 1112. The first groove portion 1111 has an opening, and the second groove portion 1112 is connected to the end of the first groove portion 1111 away from the opening. It should be noted that when the elastic portion 112 is in a free state, along the radial direction of the cam 110, the maximum width of the second groove portion 1112 is greater than the maximum width of the first groove portion 1111. It can be understood that the second groove portion 1112 is actually an enlarged portion, and the second groove portion 1112 is actually located at the connection between the elastic portion 112 and the cam 110. When the elastic portion 112 undergoes elastic deformation, a large stress is generated at the connection between the elastic portion 112 and the cam 110. However, by providing the second groove portion 1112, the stress at this location can be greatly reduced, making the elastic portion 112 more elastic and less prone to breakage during deformation.

[0047] Reference Figure 5 As shown, a wave generator 100 according to an embodiment of the present invention includes a flexible bearing 120. The flexible bearing 120 is sleeved around the cam 110. It should be noted that the flexible bearing 120 and the cam 110 are interference-fitted, causing the elastic portion 112 to elastically deform towards the groove 111. It is understood that the elastic portion 112 changes from a free state to a deformed state during this process. Furthermore, if the cam 110 is removed from the flexible bearing 120, the elastic portion 112 will change from a deformed state to a free state. Along the opening direction towards the groove 111, the outer peripheral wall of the flexible bearing 120 is inclined towards the axis of the cam 110. It should be noted that the flexible bearing 120 is a ball bearing, which includes an inner ring, an outer ring, and balls. Here, along the opening direction toward the groove 111, the outer peripheral wall of the flexible bearing 120 is inclined toward the axis of the cam 110. Specifically, along the opening direction toward the groove 111, the inner ring is inclined toward the axis of the cam 110; and along the opening direction toward the groove 111, the outer ring is inclined toward the axis of the cam 110.

[0048] Continue to refer to Figure 5 As shown, the wave generator 100 is used to cooperate with the flex wheel 200. When the wave generator 100 and the flex wheel 200 are installed and fitted, the opening of the groove 111 faces away from the end of the gear segment 210 port of the flex wheel 200, and the gear segment 210 of the flex wheel 200 is deformed outward. (Refer to...) Figure 6 As shown, due to the inclination of the outer peripheral wall of the outer ring of the flexible bearing 120, it will fit against the inner wall of the gear segment 210, and the two will be in surface contact. This reduces the outward expansion angle β of the gear segment 210 of the flexible wheel 200, that is, it reduces the stress concentration phenomenon between the wave generator 100 and the flexible wheel 200, and improves the service life of the flexible wheel 200.

[0049] One embodiment of this utility model provides a harmonic reducer 1000, as detailed in the accompanying drawings. Figure 5 and Figure 6 As shown, it includes a flexible wheel 200, a rigid wheel, and a wave generator 100 according to this embodiment of the invention. It should be noted that the flexible wheel 200 includes a gear section 210, a transition section 220, and a flange section 230. The gear section 210, transition section 220, and flange section 230 are connected sequentially. The flange section 230 is used for mounting the harmonic reducer 1000, and the gear section 210 is used for meshing with the internal teeth of the rigid wheel. The outer peripheral wall of the flexible wheel 200 is interference-fitted with the inner wall of the flexible wheel 200, and the opening of the groove 111 faces away from the end of the gear section 210 port of the flexible wheel 200, that is, towards the end of the flexible wheel 200 facing away from the gear section 210 port.

[0050] According to the harmonic reducer 1000 of this utility model embodiment, since the wave generator 100 can improve the service life of the flexible gear 200, and at the same time, when the outer peripheral wall of the outer ring of the flexible bearing 120 is in surface contact with the inner wall of the gear segment 210, the outward expansion angle of the gear segment 210 becomes smaller, and the effective meshing tooth width between the flexible gear 200 and the rigid gear becomes larger, further improving the service life of the flexible gear 200. Overall, the service life of the harmonic reducer 1000 is also improved. Since the harmonic reducer 1000 adopts all the technical solutions of the wave generator 100 of the above embodiment, it has at least all the beneficial effects brought about by the technical solutions of the above embodiment, which will not be repeated here.

[0051] One embodiment of this utility model provides a robot, which includes a harmonic reducer 1000 according to this utility model embodiment.

[0052] According to the embodiments of this utility model, the service life of the robot is also improved because the service life of the harmonic reducer 1000 is increased, thus better meeting customer needs. Since the robot adopts all the technical solutions of the harmonic reducer 1000 of the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated further here.

[0053] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model, and not to limit it. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present utility model.

Claims

1. A wave generator, characterized in that, include: A cam has a groove on one end face along the axial direction of the cam. The groove is annular. The cam has an elastic part located on the radial outer side of the groove along the cam. A flexible bearing is sleeved on the outside of the cam. The flexible bearing is interference-fitted with the cam so that the elastic part undergoes elastic deformation toward the groove. Along the opening direction toward the groove, the outer peripheral wall of the flexible bearing is inclined toward the axis of the cam.

2. The wave generator according to claim 1, characterized in that, When the elastic part is in a free state, the groove on the longitudinal section of the cam is rectangular, triangular, or trapezoidal.

3. The wave generator according to claim 1 or 2, characterized in that, The axial length of the cam is L0, the elastic part is in a free state, and the maximum depth of the groove along the axial direction of the cam is L, satisfying: L≤(L0-5mm).

4. The wave generator according to claim 1 or 2, characterized in that, The cam has an inner hole, the distance from the side wall of the inner hole to the outer peripheral wall of the cam is H, the elastic part is in a free state, and the maximum width of the groove along the radial direction of the cam is h, satisfying: 2mm≤h≤(H-4mm).

5. The wave generator according to claim 1 or 2, characterized in that, When the elastic part is in a free state, the minimum distance from the groove along the radial direction of the cam to the outer peripheral wall of the cam is b, which satisfies: b≥2mm.

6. The wave generator according to claim 1 or 2, characterized in that, The groove includes a first groove and a second groove. The first groove has the opening. The second groove is connected to the end of the first groove away from the opening. The elastic part is in a free state. Along the radial direction of the cam, the maximum width of the second groove is greater than the maximum width of the first groove.

7. The wave generator according to claim 1 or 2, characterized in that, When the elastic part is in a free state, its thickness is equal along the circumferential direction of the cam in any cross-section of the cam.

8. The wave generator according to claim 1 or 2, characterized in that, In the cross-section of the cam, the groove is elliptical and annular.

9. A harmonic reducer, characterized in that, The device includes a flexible wheel, a rigid wheel, and a wave generator as described in any one of claims 1 to 8, wherein the outer peripheral wall of the flexible bearing is interference-fitted with the inner wall of the flexible wheel, the opening of the groove faces away from the gear segment port of the flexible wheel, and the flexible wheel meshes with the rigid wheel.

10. A robot, characterized in that, Includes the harmonic reducer as described in claim 9.

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