Flexspline and Harmonic Reducer

Abstract

The present invention relates to a flexible gear and a harmonic reducer, belonging to the technical field of robotics, and is used to solve the problem that the open end of the flexible gear is prone to radial tearing. The flexible gear includes: a body having an opening; an external tooth portion provided on the outer peripheral surface of the body and close to the opening; and a reinforcing rib provided on the inner wall surface of the opening; wherein, the reinforcing rib is in a ring structure, and the reinforcing rib and the opening construct the open end of the flexible gear. In the present invention, the setting of the reinforcing rib changes the structure of the open end of the flexible gear, making the force at the open end of the flexible gear change from radial stress to axial stress. The reinforcing rib increases the radial protection of the open end, thereby reducing the risk of radial tearing of the flexible gear, and further ensuring that the harmonic reducer can work stably and reliably.

Description

Technical Field

[0001] The present invention relates to the technical field of robotic devices, and particularly to a flexible gear and a harmonic reducer. Background Art

[0002] A harmonic reducer mainly consists of a rigid gear, a flexible gear, and a harmonic generator. Under the action of the harmonic generator, the flexible gear undergoes elastic deformation, causing the outer teeth of the flexible gear to mesh with the rigid gear, thereby achieving the purpose of transmission. The deformation process of the flexible gear is a basically symmetric harmonic wave.

[0003] However, in the prior art, the thinnest position of the outer teeth of the flexible gear is at the tooth root. Due to the thin-walled cylindrical structure of the flexible gear itself and its elastic deformation characteristics, the tooth root of the flexible gear is adjacent to the meshing position, and its upper end is an open structure. This leads to the easy occurrence of radial tearing at the open end of the flexible gear, causing the harmonic reducer to fail.

[0004] That is to say, in the prior art, there is a problem that the open end of the flexible gear is prone to radial tearing. Summary of the Invention

[0005] The present invention provides a flexible gear and a harmonic reducer for solving the problem that the open end of the flexible gear is prone to radial tearing.

[0006] The present invention provides a flexible gear for a harmonic reducer, which includes: a body having an opening; an outer tooth portion provided on the outer peripheral surface of the body and close to the opening; and a reinforcing rib provided on the inner wall surface of the opening; wherein the reinforcing rib is in a ring structure, and the reinforcing rib and the opening construct the open end of the flexible gear.

[0007] In one embodiment, the central axis of the reinforcing rib coincides with the central axis of the body. In this embodiment, making the central axis of the reinforcing rib coincide with the central axis of the body enables the internal force of the reinforcing rib to be evenly distributed. Thus, it better increases the radial protection of the open end, further reduces the risk of radial tearing of the flexible gear, and ensures the stable and reliable operation of the harmonic reducer.

[0008] In one embodiment, the reinforcing rib is provided with an outer end face facing the central axis of the body, and the contour line of the outer end face is a closed curve. In this embodiment, setting the contour line of the outer end face of the reinforcing rib facing the central axis of the body as a closed curve plays a role in stress extension during the deformation process of the flexible gear, avoiding stress concentration, thereby increasing the torque-bearing capacity of the flexible gear and extending its service life.

[0009] In one embodiment, the external tooth portion includes a plurality of teeth arranged along the central axis of the body, and the contour line is a cosine curve, which includes a plurality of spaced-apart wave crests and a plurality of spaced-apart wave troughs, wherein there is one wave trough between two adjacent wave crests, the tooth tips of the plurality of teeth are arranged in one-to-one correspondence with the plurality of wave troughs, and the tooth roots of the plurality of teeth are arranged in one-to-one correspondence with the plurality of wave crests. In this embodiment, the wave crests and wave troughs of the cosine contour of the reinforcing rib respectively correspond to the tooth roots and tooth tips of the teeth of the flexspline. This increases the wall thickness at the tooth root position of the flexspline, and increases the thickness of the tooth root at the thinnest position of the flexspline. Thereby enhancing the strength of the external tooth portion. Furthermore, the load-bearing torque of the flexspline is improved, and its service life is extended. Moreover, the cosine contour plays a role in stress extension during the deformation process of the flexspline, avoiding stress concentration, thereby improving the load-bearing torque of the flexspline and extending its service life.

[0010] In one embodiment, the maximum radial distance d1 between the tooth tip of the tooth and the wave trough is not less than twice the tooth height D of the tooth.

[0011] In one embodiment, the maximum radial distance d2 between the tooth root of the tooth and the wave crest is not less than twice the tooth height D of the tooth. In this embodiment, the wave crests and wave troughs of the cosine contour of the reinforcing rib respectively correspond to the tooth roots and tooth tips of the teeth of the flexspline. This increases the wall thickness at the tooth root position of the flexspline, and increases the thickness of the tooth root at the thinnest position of the flexspline to one tooth height D. Thereby enhancing the strength of the external tooth portion. Furthermore, the load-bearing torque of the flexspline is improved, and its service life is extended. Moreover, the cosine contour plays a role in stress extension during the deformation process of the flexspline, avoiding stress concentration, thereby improving the load-bearing torque of the flexspline and extending its service life.

[0012] In one embodiment, the coordinate expression of any point A on the contour line is:

[0013] p = (a, ∮);

[0014] a = r + 0.75×h + 0.25×h×cos[(n×∮ + 1)×π];

[0015] Wherein, in the above expression, ∮ is the angle between AO and BO, in degrees, where the center of the flexspline is O, the tooth tip position of the tooth is B, the distance from the cosine contour point to the center O of the flexspline is AO, and the distance from the tooth tip position B of the tooth to the center of the flexspline is BO;

[0016] a is the distance AO from the cosine contour point to the center O of the flexspline, in mm;

[0017] r is the inner hole radius of the flexspline, in mm;

[0018] n is the number of teeth of the flexspline;

[0019] h is the full tooth height of the flexspline tooth profile, with the unit of mm. In this embodiment, when machining the contour of the outer end face of the body, CNC programming can be carried out according to this coordinate expression, thereby improving the machining accuracy of the flexspline. In addition, the above contour line formula is obtained by optimizing the cosine contour line. The contour surface of the outer end face that conforms to this contour line formula can better play the role of stress extension during the deformation process of the flexspline, thereby better avoiding stress concentration, further improving the load-bearing torque of the flexspline, and extending its service life.

[0020] In one embodiment, it further includes a limiting structure. The limiting structure is arranged on the reinforcing rib and is used to limit the installation position of the flexible bearing in the harmonic reducer.

[0021] In one embodiment, the limiting structure is the lower end face of the reinforcing rib. When the lower end face is in contact with the flexible bearing, the flexible bearing is installed in place. In this embodiment, when the lower end face is in contact with the flexible bearing, the flexible bearing is limited by the lower end face. Specifically, when the flexible bearing is assembled, the flexible bearing is installed from the other end of the flexspline, and when the end face of the flexible bearing is in contact with the lower end face, it is installed in place, thereby improving the assembly efficiency and assembly accuracy of the flexible bearing. Moreover, when the harmonic reducer is running, the lower end face restricts the degree of freedom of the flexible bearing in the first direction, thereby improving the running stability of the harmonic reducer and extending its service life.

[0022] The present invention also provides a harmonic reducer, including: a bearing having an outer ring and an inner ring; the above-mentioned flexspline connected to the outer ring of the bearing; a rigid ring meshing with the flexspline and connected to the inner ring of the bearing; and a harmonic generator arranged inside the flexspline. When the harmonic generator rotates continuously, the flexspline is continuously deformed, changing its meshing state with the rigid ring to achieve the motion transmission from the harmonic generator to the flexspline.

[0023] Compared with the prior art, the advantages of the present invention are that the arrangement of the reinforcing rib changes the structure of the open end of the flexspline, making the force on the open end of the flexspline change from radial stress to axial stress. The reinforcing rib increases the radial protection of the open end, thereby reducing the risk of radial tearing at the open end of the flexspline, and further ensuring that the harmonic reducer can work stably and reliably. In addition, the arrangement of the reinforcing rib can increase the overall thickness of the open end, thereby increasing the overall wall thickness at the tooth root position of the external tooth part, enhancing the strength of the external tooth part, further increasing the load-bearing torque of the flexspline, and extending its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the drawings.

[0025] Figure 1 It is the front view of the flexspline in the embodiment of the present invention;

[0026] Figure 2 is Figure 1 The main sectional view of the flexible gear in

[0027] Figure 3 is Figure 1 The bottom view of the flexible gear in

[0028] Figure 4 is Figure 1 The partial enlarged view at position C in

[0029] Figure 5 is Figure 1 The schematic diagram of the cosine contour position of the outer end face of the stiffening rib in

[0030] Figure 6 The schematic diagram of the structural composition of the harmonic reducer in the embodiment of the invention;

[0031] Figure 7 is Figure 6 The three-dimensional exploded view of the harmonic reducer in

[0032] Figure 8 is Figure 1 The schematic diagram of the stress on the flexible gear in (showing the axial stress);

[0033] Figure 9 is Figure 1 The schematic diagram of the stress on the flexible gear in (showing the radial stress and axial stress).

[0034] Reference numerals:

[0035] 10, body; 11, opening; 20, external tooth part; 21, teeth; 211, tooth tip; 212, tooth root; 30, stiffening rib; 31, outer end face; 311, contour line; 3111, wave crest; 3112, wave trough; 32, lower end face; 100, flexible gear; 200, flexible bearing; 300, bearing; 301, outer ring; 302, inner ring; 400, rigid gear; 500, cam. Detailed implementation manners

[0036] The present invention will be further described below with reference to the accompanying drawings.

[0037] It should be noted that the harmonic reducer in this application is used in the field of robots. The harmonic reducer has the characteristics of large transmission ratio, small volume, light weight and high transmission accuracy. The harmonic reducer is a new type of transmission method that uses the elastic deformation of a flexible working component for motion or power transmission. The harmonic reducer breaks through the mode of mechanical transmission using rigid component mechanisms and uses a flexible component to achieve mechanical transmission, thereby obtaining a series of special functions that are difficult to achieve by other transmissions. In the current field of robots, the harmonic reducer has become an irreplaceable and important component of robots.

[0038] As Figures 1 to 3 shown, the present invention provides a flexible gear 100, which is used for a harmonic reducer and includes a body 10, an external tooth portion 20, and a reinforcing rib 30. Among them, the body 10 has an opening 11, the external tooth portion 20 is arranged on the outer peripheral surface of the body 10 and is close to the opening 11, and the reinforcing rib 30 is arranged on the inner wall surface of the opening 11. The reinforcing rib 30 is a ring structure, and the opening 11 and the reinforcing rib 30 construct the open end of the flexible gear 100.

[0039] In the above setting, by arranging the reinforcing rib 30, the structure of the open end of the flexible gear 100 is changed, so that the stress received by the open end of the flexible gear 100 changes from radial stress to axial stress, increasing the radial protection of the open end of the flexible gear 100, thereby reducing the risk of radial tearing of the open end of the flexible gear 100, and further ensuring that the harmonic reducer can work stably and reliably. In addition, arranging the reinforcing rib 30 can increase the overall thickness of the open end of the flexible gear 100, thus increasing the wall thickness at the tooth root position of the external tooth portion 20, thereby enhancing the strength of the external tooth portion 20. Furthermore, the torque-carrying capacity of the flexible gear 100 is improved, and its service life is extended.

[0040] It should be noted that referring to Figure 8 and Figure 9 , in the prior art, the open end is parallel to the axis (the central axis of the flexible gear), and the open end is subjected to radial stress (parallel to the axis) during the deformation process. In the present application, the open end includes the opening 11 and the reinforcing rib 30, and the reinforcing rib 30 is perpendicular to the axis, that is, on the basis of the structure of the open end in the prior art, the reinforcing rib 30 is added. Since the stress direction of the open end is along the direction of the open end, the stress direction is subsequently changed to axial stress (perpendicular to the axis) by the reinforcing rib 30.

[0041] It should be noted that the harmonic reducer relies on the flexible gear 100 to generate repeated deformation under the action of the harmonic generator, so that the flexible gear 100 and the rigid gear 400 generate meshing motion. During the repeated deformation process of the flexible gear 100, stress concentration is caused at the open end of the flexible gear 100, and the weak point of the flexible gear 100 is in the radial direction of the tooth profile of its teeth 21. In the present application, by arranging the reinforcing rib 30, the structure of the open end of the flexible gear in the prior art (straight cylinder structure) is changed, thereby changing the stress direction received by the open end, increasing the radial protection of the open end, and further solving the problem that the open end of the flexible gear in the prior art is radially torn due to repeated deformation, so as to ensure the stable operation of the harmonic reducer and avoid its failure.

[0042] Specifically, as Figure 2As shown, in one embodiment, the central axis of the reinforcing rib 30 coincides with the central axis of the body 10. This enables the internal force of the reinforcing rib 30 to be evenly distributed, thereby better increasing the radial protection of the open end and further reducing the risk of radial tearing of the flexspline 100 to ensure the stable and reliable operation of the harmonic reducer.

[0043] Specifically, as Figure 1 and Figure 2 shown, in one embodiment, the reinforcing rib 30 is formed by bending the end of the thin-walled cylinder.

[0044] Of course, in an alternative embodiment not shown in the drawings of the present application, the reinforcing rib 30 is a welded part and is directly welded to the inner wall surface of the opening 11.

[0045] It should be noted that the external tooth part 20 is arranged on the outer peripheral surface of the body 10 and close to the opening 11, rather than directly on the outer peripheral surface of the opening 11. This avoids affecting the external tooth part 20 when welding or bending the reinforcing rib 30.

[0046] Specifically, as Figure 1 and Figure 2 shown, in one embodiment, the contour line 311 of the outer end surface 31 of the reinforcing rib 30 is a closed curve ( Figure 1 the contour of the outer end surface 31 in the direction perpendicular to the paper surface), and the outer end surface 31 faces the central axis of the body 10.

[0047] In the above setting, the contour line 311 of the outer end surface 31 of the reinforcing rib 30 is set as a closed curve. This plays a role in stress extension during the deformation process of the flexspline 100, avoiding stress concentration, thereby increasing the torque-bearing capacity of the flexspline 100 and extending its service life.

[0048] Specifically, as Figure 4 shown, in one embodiment, the external tooth part 20 includes a plurality of teeth 21 arranged along the central axis of the body 10. The contour line 311 is a cosine curve, which includes a plurality of spaced-apart wave crests 3111 and a plurality of spaced-apart wave troughs 3112. One wave trough 3112 is arranged between two adjacent wave crests 3111. The tooth tips 211 of the plurality of teeth 21 are arranged in one-to-one correspondence with the plurality of wave troughs 3112, and the tooth roots 212 of the plurality of teeth 21 are arranged in one-to-one correspondence with the plurality of wave crests 3111.

[0049] In the above setting, the peaks 3111 and valleys 3112 of the cosine profile of the reinforcing rib 30 respectively correspond to the tooth roots 212 and tooth tips 211 of the teeth 21 of the flexible gear 100. This increases the wall thickness at the tooth root position of the flexible gear and the thickness at the tooth root, which is the thinnest position of the flexible gear 100, to one tooth height D. Thereby enhancing the strength of the external tooth part 20. Furthermore, the load-bearing torque of the flexible gear 100 is increased, and its service life is extended. Moreover, the cosine profile plays a role in stress extension during the deformation process of the flexible gear 100, avoiding stress concentration, thereby increasing the load-bearing torque of the flexible gear 100 and extending its service life.

[0050] Specifically, as Figure 4 shown, in one embodiment, the maximum radial distance d1 between the tooth tip 211 of the tooth 21 and the valley 3112 is equal to two tooth heights D of the tooth 21 (i.e., the distance between the tooth root 212 of the tooth 21 and the valley 3112 is D).

[0051] Of course, according to the actual situation, the maximum radial distance d1 between the tooth tip 211 of the tooth 21 and the valley 3112 can be set to be greater than two tooth heights D of the tooth 21.

[0052] Specifically, as Figure 4 shown, in one embodiment, the maximum radial distance d2 between the tooth root 212 of the tooth 21 and the peak 3111 is equal to two tooth heights D of the tooth 21.

[0053] Of course, according to the actual situation, the maximum radial distance d2 between the tooth root 212 of the tooth 21 and the peak 3111 can be greater than two tooth heights D of the tooth 21.

[0054] In the above setting, the peaks 3111 and valleys 3112 of the cosine profile of the reinforcing rib 30 respectively correspond to the tooth roots 212 and tooth tips 211 of the teeth 21 of the flexible gear 100. This increases the wall thickness at the tooth root position of the flexible gear, and increases the thickness at the tooth root, which is the thinnest position of the flexible gear 100, to one tooth height D. Thereby enhancing the strength of the external tooth part 20. Furthermore, the load-bearing torque of the flexible gear 100 is increased, and its service life is extended. Moreover, the cosine profile plays a role in stress extension during the deformation process of the flexible gear 100, avoiding stress concentration, thereby increasing the load-bearing torque of the flexible gear 100 and extending its service life.

[0055] Specifically, referring to Figure 5 , in one embodiment, the coordinate expression of any point A on the contour line 311 is: p=(a,∮);

[0056] a = r + 0.75×h + 0.25×h×cos[(n×∮ + 1)×π];

[0057] Wherein, in the above expression, ∮ is the included angle between AO and BO, with the unit of °. The center of the flexspline 100 is O, the tooth tip position of the tooth is B, the distance from the cosine profile point to the center O of the flexspline 100 is AO, and the distance from the tooth tip position B of the tooth to the center of the flexspline 100 is BO;

[0058] a is the distance AO from the cosine profile point to the center O of the flexspline 100, with the unit of mm;

[0059] r is the inner hole radius of the flexspline, with the unit of mm;

[0060] n is the number of teeth of the flexspline;

[0061] h is the total tooth height (tooth height D) of the flexspline tooth profile, with the unit of mm.

[0062] It should be noted that when machining the contour of the outer end face 31 of the main body 10, CNC programming can be carried out according to this coordinate expression, thereby improving the machining accuracy of the flexspline 100. In addition, the above contour line formula is obtained by optimizing the cosine contour line. The contour surface of the outer end face 31 that conforms to this contour line formula can better play the role of stress extension during the deformation process of the flexspline 100, thereby better avoiding stress concentration, further improving the load-bearing torque of the flexspline 100, and extending its service life.

[0063] Specifically, as Figure 2 shown, in one embodiment, the flexspline 100 further includes a limiting structure, and the limiting structure is arranged on the reinforcing rib 30 for limiting the installation position of the flexible bearing 200 in the harmonic reducer.

[0064] Specifically, as Figure 2 shown, in one embodiment, the limiting structure is the lower end face 32 of the reinforcing rib 30. When the lower end face 32 is in contact with the flexible bearing 200, the flexible bearing 200 is installed in place.

[0065] In the above setting, the lower end face 32 is in contact with the flexible bearing 200, and the flexible bearing 200 is limited by the lower end face 32. Specifically, when the flexible bearing 200 is assembled, the flexible bearing 200 is installed from the other end of the flexspline 100, and when the end face of the flexible bearing is in contact with the lower end face 32, it is installed in place, thereby improving the assembly efficiency and assembly accuracy of the flexible bearing 200. Moreover, when the harmonic reducer is running, the lower end face 32 restricts the degree of freedom of the flexible bearing 200 in the first direction ( Figure 3 the vertical direction in

[0066] ), thereby improving the running stability of the harmonic reducer and extending its service life. Figure 6 and Figure 7As shown in the figure, the present invention also provides a harmonic reducer, which includes a bearing 300, the above-mentioned flexible gear 100, a rigid gear 400 and a harmonic generator. Among them, the bearing 300 has an outer ring 301 and an inner ring 302. The flexible gear 100 is connected to the outer ring 301 of the bearing 300, the rigid gear 400 meshes with the flexible gear 100, and the rigid gear 400 is connected to the inner ring 302 of the bearing 300. The harmonic generator is arranged inside the flexible gear 100. When the harmonic generator rotates continuously, the flexible gear 100 continuously deforms, changing its meshing state with the rigid gear 400, so as to realize the motion transfer from the harmonic generator to the flexible gear 100.

[0067] Specifically, as Figure 6 and Figure 7 shown, in one embodiment, the harmonic generator includes a cam 500 and a flexible bearing 200 arranged on the outer periphery of the cam 500.

[0068] Specifically, as Figure 6 and Figure 7 shown, in one embodiment, the bearing 300 adopts a crossed roller bearing.

[0069] Specifically, as Figure 6 and Figure 7 shown, in one embodiment, the inner ring of the flexible bearing 200 is fixedly connected to the outer peripheral surface of the cam 500.

[0070] It should be noted that the principle of the harmonic reducer in this application refers to using the relative motion of the flexible gear 100, the rigid gear 400 and the wave generator, mainly the controllable elastic deformation of the flexible gear 100 to realize the motion and power transmission. The elliptical cam 500 inside the harmonic generator rotates inside the flexible gear 100 to cause the flexible gear 100 to deform. When the teeth of the flexible gear and the rigid gear at both ends of the long axis of the elliptical cam in the harmonic generator enter into meshing, the teeth of the flexible gear at both ends of the short axis are disengaged from the teeth of the rigid gear. For the teeth between the long axis and the short axis of the harmonic generator, they are in a semi-meshing state of gradually entering into meshing in different sections along the circumferences of the flexible gear 100 and the rigid gear 400, which is called tooth engagement; and in a semi-meshing state of gradually withdrawing from meshing, which is called tooth disengagement. When the harmonic generator rotates continuously, the flexible gear 100 continuously deforms, causing the teeth of the two gears to continuously change their original working states in the four motions of tooth engagement, meshing, tooth disengagement and disconnection, generating a tooth staggering motion, and realizing the motion transfer from the harmonic generator to the flexible gear 100.

[0071] It should be noted that the present invention provides a flexspline 100, with reinforcing ribs 30 facing the axis arranged on the inner side of its opening portion 11, which increases the radial protection of the opening end of the flexspline 100 and prevents radial tearing at the opening end. The end face of the body 10 is set to a cosine profile, where the peaks 3111 of the cosine profile correspond to the roots 212 of the teeth of the flexspline, and the valleys 3112 correspond to the tooth tip positions. At the weakest position of the flexspline 100, i.e., at the root, the thickness is increased by one tooth height, which increases the strength of the flexspline 100, enables the harmonic reducer to have a higher load-bearing torque, and extends its service life. During the repeated deformation of the flexspline, the cosine profile can extend and disperse the stress, avoiding the failure of the flexspline 100 caused by stress concentration, thereby extending the service life of the harmonic reducer.

[0072] In the harmonic reducer of the present invention, the above-mentioned flexspline 100 is adopted. By strengthening the root thickness and stress extension during deformation, the problem of tearing at the opening end of the flexspline 100 is avoided, the life of the flexspline 100 is extended, thereby increasing the load-bearing torque of the harmonic reducer and extending its service life. On the other hand, by adding a limiting structure to the flexspline 100, the freedom degree of the flexible bearing 200 is restricted, the operation stability of the harmonic reducer is improved, and its service life is extended.

[0073] From the description of the above specific embodiments, it can be seen that by setting the reinforcing ribs, the force on the opening end of the flexspline changes from radial stress to axial stress. The reinforcing ribs increase the radial protection of the opening end, thereby reducing the risk of radial tearing at the opening end of the flexspline, and further ensuring the stable and reliable operation of the harmonic reducer. In addition, setting the reinforcing ribs can increase the thickness of the opening end, which increases the wall thickness at the root position of the external tooth part, thereby enhancing the strength of the external tooth part. Further, the load-bearing torque of the flexspline is increased and its service life is extended. The peaks and valleys of the cosine profile of the reinforcing ribs correspond to the roots and tips of the teeth of the flexspline respectively. This increases the wall thickness at the root position of the flexspline teeth and the thickness at the root of the thinnest position of the flexspline. Thereby enhancing the strength of the external tooth part. Further, the load-bearing torque of the flexspline is increased and its service life is extended. Moreover, the cosine profile plays a role in stress extension during the deformation of the flexspline, avoiding stress concentration, thereby increasing the load-bearing torque of the flexspline and extending its service life. When machining the profile of the outer end face of the body, numerical control programming can be carried out according to this coordinate expression. Thereby improving the machining accuracy of the flexspline. In addition, the above profile line formula is obtained by optimizing the cosine profile line. The profile surface of the outer end face conforming to this profile line formula can better play the role of stress extension during the deformation of the flexspline, thereby better avoiding stress concentration, further increasing the load-bearing torque of the flexspline and extending its service life.

[0074] In the present invention, the terms "first", "second", and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "plural" means two or more, unless otherwise specifically defined. The terms "mounted", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "coupled" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0075] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0076] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0077] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

[0078] Although the present invention has been described with reference to the preferred embodiments, various improvements can be made to it and components thereof can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any manner. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A flexspline, characterized in that, The flexspline is used in a harmonic reducer and includes: A body having an opening; and An external tooth portion provided on the outer peripheral surface of the body and near the opening; and Reinforcing ribs provided on the inner wall surface of the opening; Wherein, the reinforcing ribs are of an annular structure, and the reinforcing ribs and the opening construct the open end of the flexspline; The reinforcing ribs are provided with an outer end surface, the outer end surface faces the central axis of the body, and the contour line of the outer end surface is a closed curve; The external tooth portion includes a plurality of teeth arranged circumferentially along the body, the contour line is a cosine curve, which includes a plurality of spaced-apart wave crests and a plurality of spaced-apart wave troughs, wherein one wave trough is provided between two adjacent wave crests, and the tooth tips of the plurality of teeth are arranged in one-to-one correspondence with the plurality of wave troughs, and the tooth roots of the plurality of teeth are arranged in one-to-one correspondence with the plurality of wave crests.

2. The flexspline according to claim 1, wherein, The central axis of the reinforcing ribs coincides with the central axis of the body.

3. The flexspline according to claim 1, wherein, The maximum radial distance d1 between the tooth tip of the tooth and the wave trough is not less than two tooth heights D of the tooth.

4. The flexspline according to claim 1, characterized in that, The maximum radial distance d2 between the tooth root of the tooth and the wave crest is not less than two tooth heights D of the tooth.

5. The flexspline according to claim 1, wherein The coordinate expression of any point A on the contour line is: p=(a,∮); a=r+0.75×h+0.25×h×cos[(n×∮+1)×π]; Wherein, in the above expression, ∮ is the angle between AO and BO, and the unit is °, wherein the center of the flexspline is O, the tooth tip position of the tooth is B, the distance from the cosine contour point to the center O of the flexspline is AO, and the distance from the tooth tip position B of the tooth to the center of the flexspline is BO; a is the distance AO from the cosine contour point to the center O of the flexspline, and the unit is mm; r is the inner hole radius of the flexspline, and the unit is mm; n is the number of teeth of the flexspline; h is the full tooth height of the tooth profile of the flexspline, and the unit is mm.

6. The flexspline according to any one of claims 1 to 5, characterized in that It further includes a limiting structure, and the limiting structure is provided on the reinforcing ribs for limiting the installation position of the flexible bearing in the harmonic reducer.

7. The flexspline according to claim 6, wherein The limiting structure is the lower end surface of the reinforcing ribs, and when the lower end surface is in contact with the flexible bearing, the flexible bearing is installed in place.

8. A harmonic reducer, characterized in that, It includes: A bearing having an outer ring and an inner ring; The flexspline according to any one of claims 1 to 7, connected to the outer ring of the bearing; And A rigid ring, meshing with the flexspline, and the rigid ring is connected to the inner ring of the bearing; And A harmonic generator provided in the flexspline; Wherein, when the harmonic generator rotates continuously, the flexspline is continuously deformed, changing its meshing state with the rigid ring to realize the motion transmission from the harmonic generator to the flexspline.

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