Harmonic speed reducer and industrial robot

Abstract

The utility model discloses a harmonic wave speed reducer and industrial robot relates to speed reducer technical field, wherein harmonic wave speed reducer includes rigid gear, flexible gear and wave generator, the wave generator is coaxially installed in flexible gear inner bore, flexible gear outer tooth portion and rigid gear inner tooth portion mesh. The outer tooth portion is arranged on a cylinder portion of the flexible gear, a convex tooth of the outer tooth portion comprises a first shape correction section, a middle section and a second shape correction section which are sequentially connected, the tooth height of the first shape correction section and the tooth height of the second shape correction section are gradually reduced in the direction away from the middle section, and the ratio of the width of the first shape correction section to the width of the convex tooth is designed to range from 0.2 to 0.35. And the ratio of the width of the middle section to the width of the convex teeth is 0.35-0.45, and the ratio of the width of the second modification section to the width of the convex teeth is 0.25-0.4, so that the meshing stability of the convex teeth and the inner tooth part can be ensured, the interference between the convex teeth and the inner tooth part can be reduced, the frictional wear of the tooth surface can be reduced, and the service life of the flexible gear can be prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of reducers, in particular to a harmonic reducer and an industrial robot. Background Art

[0002] In the related art, the harmonic reducer includes a wave generator, a flexible wheel and a rigid wheel. The flexible wheel is sleeved on the wave generator, and the outer teeth of the flexible wheel mesh with the inner teeth of the rigid wheel. The flexible wheel undergoes elastic deformation under the action of the wave generator, and the shape and position of the deformed flexible wheel tooth profile will change. If the deformation of the flexible wheel is too large or uneven, the outer teeth of the flexible wheel and the inner teeth of the rigid wheel may interfere with each other during the meshing process. This can easily lead to severe wear between the inner and outer teeth, resulting in tooth skipping and slippage, and shortening the service life of the harmonic reducer. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides a harmonic reducer, which can reduce the interference between the outer teeth of the flexible wheel and the inner teeth of the rigid wheel, so as to increase the service life of the harmonic reducer.

[0004] The utility model also provides an industrial robot having the harmonic reducer.

[0005] According to the first aspect of the present utility model, the harmonic reducer comprises: a rigid wheel having an inner tooth portion;

[0006] A flexible wheel, comprising a cylinder, a diaphragm and a flange, wherein the cylinder is provided with an outer tooth portion cooperating with the inner tooth portion, the outer tooth portion is coaxially installed in the inner tooth portion, the diaphragm is connected to an end of the cylinder away from the outer tooth portion and extends to the outside of the cylinder, and the flange is connected to the outer peripheral edge of the diaphragm;

[0007] a wave generator coaxially mounted on the inner hole of the flexspline, the wave generator being configured to mesh the outer tooth portion with the inner tooth portion when rotating;

[0008] Wherein, the outer tooth portion includes a convex tooth arranged around the circumference of the barrel portion, and in the direction from the outer tooth portion to the flange portion, the convex tooth includes a first trimming segment, an intermediate segment and a second trimming segment connected in sequence, and the tooth height of the first trimming segment and the tooth height of the second trimming segment are gradually reduced in the direction away from the intermediate segment, respectively, and in the direction parallel to the rotation axis of the wave generator, the tooth width of the convex tooth is Lf1, the width of the first trimming segment is Lf2, the width of the intermediate segment is Lf3, and the width of the second trimming segment is Lf4, satisfying:

[0009] 0.2*Lf1≤Lf2≤0.35*Lf1;

[0010] 0.35*Lf1≤Lf3≤0.45*Lf1;

[0011] 0.25*Lf1≤Lf4≤0.4*Lf1.

[0012] The harmonic reducer according to the embodiment of the utility model has at least the following beneficial effects:

[0013] By arranging a wave generator to be coaxially installed on the inner hole of the flexible wheel, the outer tooth portion of the flexible wheel meshes with the inner tooth portion of the rigid wheel, so that when the wave generator rotates, it can drive the flexible wheel and the rigid wheel to rotate relative to each other. The outer tooth portion is arranged on the cylinder portion of the flexible wheel, and the cylinder portion is also connected to the diaphragm portion, and the diaphragm portion is connected to the flange portion. The outer tooth portion includes a convex tooth. Since the convex tooth is easy to interfere with the inner tooth portion at both ends along the axial direction, the convex tooth is arranged to include a first trimming section, an intermediate section, and a second trimming section connected in sequence, and the tooth height of the first trimming section and the tooth height of the second trimming section are gradually reduced in the direction away from the intermediate section, which can effectively reduce the interference between the convex tooth and the inner tooth portion. At the same time, the ratio of the width of the first modified section to the width of the convex tooth is reasonably designed to be between 0.2 and 0.35, the ratio of the width of the middle section to the width of the convex tooth is between 0.35 and 0.45, and the ratio of the width of the second modified section to the width of the convex tooth is between 0.25 and 0.4. While ensuring the meshing stability of the convex tooth and the inner tooth, it can also reduce the interference between the convex tooth and the inner tooth, thereby reducing the friction and wear of the tooth surface, which is beneficial to extending the life of the flexible wheel.

[0014] According to some embodiments of the present invention, the tooth top of the first trimming section is constructed as a first inclined plane inclined in a direction away from the middle section and toward the rotation axis, and the tooth top of the second trimming section is constructed as a second inclined plane inclined in a direction away from the middle section and toward the rotation axis, and the inclination angle of the second inclined plane is greater than the inclination angle of the first inclined plane.

[0015] According to some embodiments of the present invention, the tooth top of the first shaping section is constructed as a first inclined surface inclined in a direction away from the middle section and toward the rotation axis, and the inclination angle of the first inclined surface is α1, satisfying: 0.3°≤α1≤1°.

[0016] According to some embodiments of the present invention, the tooth top of the second shaping section is constructed as a second inclined plane inclined in a direction away from the middle section and toward the rotation axis, and the inclination angle of the second inclined plane is β1, satisfying: 0.3°≤β1≤1°, and β1≥α1.

[0017] According to some embodiments of the present invention, the minimum distance between the end wall of the barrel portion away from the flange portion and the flange portion is Lf, and the maximum length of the inner tooth portion along the direction of the rotation axis is Lc, satisfying: 0.5*Lf≤Lc≤0.6*Lf.

[0018] According to some embodiments of the present invention, the minimum distance between the end wall of the barrel portion facing away from the flange portion and the flange portion is Lf, which satisfies: 0.45*Lf≤Lf1≤0.55*Lf.

[0019] According to some embodiments of the present invention, one end of the second trimming section facing the flange portion is transitionally connected to the cylinder portion via an arc section.

[0020] According to some embodiments of the utility model, the connection between the diaphragm and the cylinder is constructed as a corner portion, the inner and outer sides of the corner portion are respectively constructed as a first arc segment and a second arc segment, the outer side of the diaphragm is constructed as a first section, the inner side of the diaphragm is constructed as a first curved segment and a second section, the two ends of the first curved segment are respectively connected to the inner side of the flange portion and the second section, the first curved segment is composed of at least two arc segments, one of the first segment and the second segment is a first straight line segment, and the other is a second curved segment, and the second curved segment is composed of at least one arc segment.

[0021] According to some embodiments of the utility model, the connection between the diaphragm and the cylinder is constructed as a corner portion, the cylinder includes a first cylinder section and a second cylinder section connected to each other, the external tooth portion is arranged on the first cylinder section, the inner side of the second cylinder section is constructed as a third section, the outer side of the second cylinder section is constructed as a fourth section, one of the third section and the fourth section is a second straight line segment, and the other is a third straight line segment and a third curved segment connected to each other, the third curved segment is closer to the corner portion than the third straight line segment, and the third curved segment is composed of at least two circular arc segments.

[0022] According to some embodiments of the utility model, the effective length of the diaphragm is Lf5, and the radial distances from point a, point b, point d, and point e of the diaphragm to the end portion of the diaphragm connected to one end of the flange portion are defined as La, Lb, Ld, and Le, respectively, wherein:

[0023] La=0.02*Lf5;

[0024] Lb=0.1*Lf5;

[0025] Ld=0.45*Lf5;

[0026] Le=0.86*Lf5;

[0027] The wall thicknesses of the diaphragm at the point a, the point b, the point d, and the point e are ta, tb, td, and te respectively;

[0028] The connection between the diaphragm and the cylinder is configured as a corner portion, and the maximum wall thickness of the corner portion is to;

[0029] Satisfies: td<tb<te≤to<ta≤2*td.

[0030] According to some embodiments of the present invention, the minimum distance between the end wall of the barrel away from the flange and the flange is Lf, and the axial distances from the g point, h point, i point, j point, k point, and m point of the barrel to the outer side wall of the flange are defined as Lg, Lh, Li, Lj, Lk, and Lm, respectively, wherein:

[0031] Lg=0.04*Lf;

[0032] Lh=0.10*Lf;

[0033] Li=0.20*Lf;

[0034] Lj=0.30*Lf;

[0035] Lk=0.40*Lf;

[0036] Lm=0.45*Lf;

[0037] The wall thicknesses of the barrel at the points g, h, i, j, k and m are tg, th, ti, tj, tk and tm respectively;

[0038] The connection between the diaphragm and the cylinder is configured as a corner portion, and the maximum wall thickness of the corner portion is to;

[0039] Satisfies: th≤tg<ti≤to<tj≤tk<tm.

[0040] The industrial robot according to the embodiment of the second aspect of the utility model includes the harmonic reducer described in the above embodiment.

[0041] The industrial robot according to the embodiment of the utility model has at least the following beneficial effects:

[0042] The harmonic reducer of the embodiment of the first aspect is adopted. The harmonic reducer is coaxially installed in the inner hole of the flexible wheel by arranging a wave generator. The outer tooth portion of the flexible wheel meshes with the inner tooth portion of the rigid wheel. Therefore, when the wave generator rotates, it can drive the flexible wheel and the rigid wheel to rotate relative to each other. The outer tooth portion is arranged on the cylinder portion of the flexible wheel, and the cylinder portion is also connected to the diaphragm portion, and the diaphragm portion is connected to the flange portion. The outer tooth portion includes convex teeth. Since the convex teeth are prone to interfere with the inner tooth portion at both ends along the axial direction, the convex teeth are arranged to include a first trimming section, an intermediate section, and a second trimming section connected in sequence, and the tooth height of the first trimming section and the tooth height of the second trimming section are gradually reduced in the direction away from the intermediate section, which can effectively reduce the interference between the convex teeth and the inner tooth portion. At the same time, the ratio of the width of the first modified section to the width of the convex tooth is reasonably designed to be between 0.2 and 0.35, the ratio of the width of the middle section to the width of the convex tooth is between 0.35 and 0.45, and the ratio of the width of the second modified section to the width of the convex tooth is between 0.25 and 0.4. While ensuring the meshing stability of the convex tooth and the inner tooth, it can also reduce the interference between the convex tooth and the inner tooth, thereby reducing the friction and wear of the tooth surface, which is beneficial to extending the life of the flexible wheel.

[0043] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0045] Figure 1 A cross-sectional schematic diagram of a harmonic reducer according to an embodiment of the utility model;

[0046] Figure 2 It is a partial structural cross-sectional view of the cooperation between the flexible wheel and the rigid wheel in one embodiment of the utility model;

[0047] Figure 3 A partial structural cross-sectional view of an outer tooth portion of an embodiment of the utility model;

[0048] Figure 4 A partial structural cross-sectional view of an outer tooth portion of an embodiment of the utility model;

[0049] Figure 5 for Figure 2 The enlarged view of point A in the middle;

[0050] Figure 6 This is a structural cross-sectional view of a diaphragm of another embodiment of the utility model;

[0051] Figure 7 A partial structural cross-sectional view of a flexible wheel according to an embodiment of the utility model;

[0052] Figure 8for Figure 7 The enlarged view of point B in the middle;

[0053] Fig. 9 This is a partial structural cross-sectional view of the second barrel portion of another embodiment of the utility model.

[0054] Figure Number:

[0055] Harmonic reducer 1000;

[0056] The rigid wheel 100; the inner tooth portion 110;

[0057] Flexspline 200; cylinder 210; first cylinder section 211; second cylinder section 212; third section 2121; fourth section 2122; second straight section 2123; third curved section 2124; third straight section 2125; diaphragm 220; first section 221; first straight section 2211; second section 222; second curved section 2221; first curved section 223; flange 230; external tooth 240; convex tooth 241; first trimming section 242; first inclined surface 2421; third inclined surface 2422; middle section 243; second trimming section 244; second inclined surface 2441; fourth inclined surface 2442; corner 250; first arc section 251; second arc section 252; arc section 260;

[0058] Wave generator 300; cam 310; flexible bearing 320;

[0059] Support bearing 400. DETAILED DESCRIPTION

[0060] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0061] In the description of the present invention, it should be understood that the descriptions involving orientation, such as the orientation or positional relationship indicated as up, down, etc., are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0062] In the description of the present utility model, "a plurality" means more than two. If there is a description of "first" or "second", it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0063] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0064] Reference Figure 1 and Figure 2 As shown, a harmonic reducer 1000 of an embodiment of the utility model can be used in a robot to realize the function of motor deceleration. The harmonic reducer 1000 includes a rigid wheel 100, a flexible wheel 200, a wave generator 300 and a support bearing 400. The rigid wheel 100 is annular and has an inner tooth portion 110 on its inner side wall. The inner tooth portion 110 is arranged circumferentially around the rigid wheel 100. The flexible wheel 200 includes a barrel 210, a diaphragm 220 and a flange 230. The barrel 210 is cylindrical and has an outer side wall at one end of the barrel 210 provided with an outer tooth portion 240 that matches the inner tooth portion 110. The outer tooth portion 240 is coaxially mounted in the inner tooth portion 110. The diaphragm 220 is connected to one end of the barrel 210 away from the outer tooth portion 240 and is arranged to extend along the outer side of the barrel 210. Extending along the outer side of the barrel 210 means extending in a direction away from the rotation axis of the harmonic reducer 1000. The flange 230 is annular and the inner side wall of the flange 230 is connected to the outer periphery of the diaphragm 220. The flange 230 is used to connect with the support bearing 400. The wave generator 300 is coaxially mounted on the inner hole of the flexible wheel 200. The wave generator 300 includes a cam 310 and a flexible bearing 320. The flexible bearing 320 is sleeved on the outer side wall of the cam 310, so that the flexible bearing 320 can be deformed under the action of the cam 310. When the cam 310 rotates under the drive of the motor, the inner ring of the flexible bearing 320 is driven to rotate synchronously, so that the shape of the outer ring of the flexible bearing 320 changes repeatedly, so that the outer tooth portion 240 and the inner tooth portion 110 are engaged.

[0065] Reference Figure 3 As shown, the outer tooth portion 240 includes a convex tooth 241 arranged around the circumference of the barrel portion 210, and the direction from the outer tooth portion 240 to the flange portion 230, that is, Figure 3 From right to left in the middle, the convex tooth 241 includes a first trimming section 242, a middle section 243, and a second trimming section 244 connected in sequence, and the tooth height of the first trimming section 242 and the tooth height of the second trimming section 244 gradually decrease in the direction away from the middle section 243. The tooth height refers to the height in the radial direction. For example, the tooth tops of the first trimming section 242 and the second trimming section 244 can be inclined in a straight line direction, or be an outward convex arc, an inward concave arc, etc.

[0066] Along the direction parallel to the rotation axis of the wave generator 300, the tooth width of the convex tooth 241 is Lf1, and the width of the first modified section 242 is Lf2, which satisfies: 0.2*Lf1≤Lf2≤0.35*Lf1, for example, the value of Lf2 can be 0.2*Lf1, 0.23*Lf1, 0.24*Lf1, 0.25*Lf1, 0.3*Lf1, 0.35*Lf1. The width of the middle section 243 is Lf3, which satisfies: 0.35*Lf1≤Lf3≤0.45*Lf1, for example, the value of Lf3 can be 0.35*Lf1, 0.38*Lf1, 0.39*Lf1, 0.40*Lf1, 0.42*Lf1, 0.45*Lf1. The width of the second shaping section 244 is Lf4, which satisfies: 0.25*Lf1≤Lf4≤0.4*Lf1. For example, the value of Lf4 can be 0.25*Lf1, 0.28*Lf1, 0.3*Lf1, 0.35*Lf1, 0.38*Lf1, or 0.4*Lf1.

[0067] It can be understood that, since the flexible wheel 200 is transformed into an elliptical shape by the action of the wave generator 300, there is an opening angle, and the motion trajectories of the outer tooth portion 240 at different interfaces are different. The state of the middle part of the convex tooth 241, that is, the middle section 243 is optimal and is not prone to interference, while the two ends of the convex tooth 241 along the axial direction are prone to interference with the inner tooth portion 110. To this end, by designing the tooth height of the first trimming section 242 and the tooth height of the second trimming section 244 to gradually decrease in the direction away from the middle section 243, the interference between the tooth top of the first trimming section 242 and the tooth top of the second trimming section 244 and the inner tooth portion 110 can be effectively reduced.

[0068] The widths of the first trimming section 242, the middle section 243, and the second trimming section 244 will affect the meshing effect with the inner tooth portion 110. When Lf2 is less than 0.2*Lf1, that is, the width of the first trimming section 242 is small, it is easy to interfere with the inner tooth portion 110. When Lf2 is greater than 0.4*Lf1, that is, the width of the first trimming section 242 is large, when the width of the convex tooth 241 remains unchanged, the width of the middle section 243 needs to be shortened accordingly, resulting in a reduction in the effective meshing area between the outer tooth portion 240 and the inner tooth portion 110, and poor stability during meshing. When Lf3 is less than 0.35*Lf1, that is, the width of the middle section 243 is small, it will also result in a reduction in the effective meshing area between the outer tooth portion 240 and the inner tooth portion 110, and poor stability during meshing. When Lf3 is greater than 0.45*Lf1, the width of the first trimming section 242 and the second trimming section 244 need to be reduced accordingly while the width of the convex tooth 241 remains unchanged, which may easily interfere with the inner tooth portion 110 at the first trimming section 242 and the second trimming section 244. When Lf4 is less than 0.25*Lf1, that is, the width of the second trimming section 244 is small, which may easily interfere with the inner tooth portion 110. When Lf4 is greater than 0.45*Lf1, that is, the width of the second trimming section 244 is large, while the width of the convex tooth 241 remains unchanged, the width of the middle section 243 needs to be shortened accordingly, resulting in a reduction in the effective meshing area between the outer tooth portion 240 and the inner tooth portion 110, and poor stability during meshing.

[0069] Therefore, the ratio of the width of the first trimming section 242 to the width of the convex tooth 241 is reasonably designed to be between 0.2 and 0.35, the ratio of the width of the middle section 243 to the width of the convex tooth 241 is between 0.35 and 0.45, and the ratio of the width of the second trimming section 244 to the width of the convex tooth 241 is between 0.25 and 0.4. While ensuring the meshing stability of the convex tooth 241 and the inner tooth portion 110, the interference between the outer tooth portion 240 and the inner tooth portion 110 can be reduced, thereby reducing the friction and wear of the tooth surface, which is beneficial to extending the life of the flexible wheel 200.

[0070] Reference Figure 4As shown, in the embodiment of the utility model, the tooth top of the first trimming section 242 is configured as a first inclined surface 2421, and the first inclined surface 2421 is inclined in a direction away from the middle section 243 and toward the direction of the rotation axis. The tooth top of the second trimming section 244 is configured as a second inclined surface 2441, and the second inclined surface 2441 is inclined in a direction away from the middle section 243 and toward the direction of the rotation axis. Among them, the inclination angle of the second inclined surface 2441 is greater than the inclination angle of the first inclined surface 2421. It should be noted that the inclination angle of the first inclined surface 2421 refers to the angle α1 between the first inclined surface 2421 and the rotation axis, and the inclination angle of the second inclined surface 2441 refers to the angle β1 between the second inclined surface 2441 and the rotation axis. It can be understood that when the wave generator 300 is embedded in the inner hole of the cylinder 210, the outer wall of the cylinder 210 will be tilted, that is, an opening angle will be formed. Since the second shaping section 244 is closer to the flange 230 than the first shaping section 242, the second shaping section 244 is more likely to interfere with the inner tooth portion 110. Therefore, by setting the inclination angle of the second inclined surface 2441 to be greater than the inclination angle of the first inclined surface 2421, the interference between the second shaping section 244 and the inner tooth portion 110 can be effectively reduced or avoided, and the contact area between the second shaping section 244 and the inner tooth portion 110 can be increased to improve the stability during power transmission.

[0071] Continue to refer to Figure 4 As shown, in the embodiment of the utility model, in order to further reduce the interference between the outer tooth portion 240 and the inner tooth portion 110, a third inclined surface 2422 is provided between two adjacent first trimming sections 242, and the third inclined surface 2422 is inclinedly arranged in the direction away from the middle section 243 and in the direction of the rotation axis. A fourth inclined surface 2442 is provided between two adjacent second trimming sections 244, and the fourth inclined surface 2442 is inclinedly arranged in the direction away from the middle section 243 and in the direction of the rotation axis. Among them, the inclination angle of the third inclined surface 2422 and the inclination angle of the first inclined surface 2421 can be the same or different, and the inclination angle of the fourth inclined surface 2442 and the inclination angle of the second inclined surface 2441 can be the same or different. Thereby, the interference between the tooth top of the inner tooth portion 110 and the tooth root of the outer tooth portion 240 can be effectively reduced or avoided, so as to reduce the friction and wear of the tooth surface and extend the life of the flexible wheel 200.

[0072] Continue to refer to Figure 4As shown, in the embodiment of the utility model, the inclination angle of the first inclined surface 2421 is α1, which satisfies: 0.3°≤α1≤1°, for example, the value of α1 can be 0.3°, 0.4°, 0.6°, 0.7°, 0.9°, 1°. When α1 is less than 0.3°, that is, the inclination angle of the first inclined surface 2421 is too small, it is difficult to reduce the interference between the inner tooth portion 110 and the outer tooth portion 240. When α1 is greater than 1°, it is easy to cause the effective area of ​​the first trimming section 242 and the inner tooth portion 110 to be reduced when meshing, thereby causing the stability of the meshing to deteriorate. The inclination angle of the third inclined surface 2422 is α2, which satisfies: 0.3°≤α2≤1°, for example, the value of α2 can be 0.3°, 0.4°, 0.6°, 0.7°, 0.9°, 1°. When α2 is less than 0.3°, that is, the inclination angle of the third inclined surface 2422 is too small, it is difficult to reduce the interference between the inner tooth portion 110 and the outer tooth portion 240. When α2 is greater than 1°, it is easy to reduce the strength of the outer tooth portion 240, and it is easy to tear between adjacent convex teeth 241. Therefore, a reasonable design of the size of α1 and α2 can effectively reduce the interference between the inner tooth portion 110 and the outer tooth portion 240, improve the service life of the flexible wheel 200, and ensure that the outer tooth portion 240 has appropriate strength and high reliability.

[0073] Continue to refer to Figure 4 As shown, in the embodiment of the utility model, the inclination angle of the second inclined surface 2441 is β1, which satisfies: 0.3°≤β1≤1°, for example, the value of β1 can be 0.3°, 0.4°, 0.6°, 0.7°, 0.9°, 1°. When β1 is less than 0.3°, that is, the inclination angle of the second inclined surface 2441 is too small, it is difficult to reduce the interference between the inner tooth portion 110 and the outer tooth portion 240. When β1 is greater than 1°, it is easy to cause the effective area of ​​the second trimming section 244 and the inner tooth portion 110 to be reduced when meshing, thereby causing the stability of the meshing to deteriorate. The inclination angle of the fourth inclined surface 2442 is β2, which satisfies: 0.3°≤β2≤1°, for example, the value of β2 can be 0.3°, 0.4°, 0.6°, 0.7°, 0.9°, 1°. When β2 is less than 0.3°, that is, the inclination angle of the fourth inclined surface 2442 is too small, it is difficult to reduce the interference between the inner tooth portion 110 and the outer tooth portion 240. When β2 is greater than 1°, it is easy to reduce the strength of the outer tooth portion 240, and it is easy to tear between adjacent convex teeth 241. Therefore, a reasonable design of the size of β1 and β2 can effectively reduce the interference between the inner tooth portion 110 and the outer tooth portion 240, improve the service life of the flexible wheel 200, and at the same time ensure that the outer tooth portion 240 has appropriate strength and high reliability.

[0074] Wherein, β1≥α1. It can be understood that, since the second trimming section 244 is closer to the flange portion 230 than the first trimming section 242, the second trimming section 244 is more likely to interfere with the inner tooth portion 110. Therefore, by setting the inclination angle of the second inclined surface 2441 to be greater than the inclination angle of the first inclined surface 2421, the interference between the second trimming section 244 and the inner tooth portion 110 can be effectively reduced or avoided, and the contact area between the second trimming section 244 and the inner tooth portion 110 can be increased, so as to improve the stability during power transmission.

[0075] Reference Figure 2 As shown, in the embodiment of the present invention, the minimum distance between the end wall of the end of the barrel 210 away from the flange 230 and the flange 230 is Lf, and the maximum length of the inner tooth portion 110 along the axial direction of the rotating shaft is Lc, which satisfies: 0.5*Lf≤Lc≤0.6*Lf, wherein the value of Lc can be 0.5*Lf, 0.51*Lf, 0.53*Lf, 0.55*Lf, 0.58*Lf, 0.6*Lf. When Lc is less than 0.5*Lf, that is, the maximum length of the inner tooth portion 110 is short, resulting in a reduction in the tooth surface contact area between the inner tooth portion 110 and the outer tooth portion 240, an increase in contact stress, and a reduction in the bearing capacity of the harmonic reducer 1000. When Lc is greater than 0.6*Lf, that is, the maximum length of the inner tooth portion 110 is large, the space occupied is too much, and the strength margin is too large, which is not conducive to the miniaturization design of the harmonic reducer 1000. Therefore, a reasonable design of the maximum length Lc and Lf of the inner tooth portion 110 can effectively increase the tooth surface contact area between the inner tooth portion 110 and the outer tooth portion 240, reduce the contact stress, and improve the load-bearing capacity of the harmonic reducer 1000, while being conducive to the miniaturization design of the harmonic reducer 1000.

[0076] Continue to refer to Figure 2As shown, in the embodiment of the present invention, the minimum distance between the end wall of the barrel 210 away from the flange 230 and the flange 230 is Lf, and the tooth width of the convex tooth 241 along the direction parallel to the rotation axis of the wave generator 300 is Lf1, which satisfies: 0.45*Lf≤Lf1≤0.55*Lf, for example, the value of Lf1 can be 0.45*Lf, 0.46*Lf, 0.48*Lf, 0.5*Lf, 0.51*Lf, 0.55*Lf. When Lf1 is less than 0.45*Lf, that is, the tooth width of the convex tooth 241 is small, resulting in a reduction in the tooth surface contact area between the inner tooth portion 110 and the outer tooth portion 240, an increase in contact stress, and a reduction in the load-bearing capacity of the harmonic reducer 1000. When Lf1 is greater than 0.6*Lf, that is, the tooth width of the convex tooth 241 is larger, and the space occupied is more, which is not conducive to the flexible deformation of the cylinder 210, resulting in a decrease in the deformation capacity of the flexible wheel 200. Therefore, by reasonably designing the proportional relationship between Lf1 and Lf, the tooth surface contact area of ​​the inner tooth portion 110 and the outer tooth portion 240 can be increased, the contact stress can be reduced, and the load-bearing capacity of the harmonic reducer 1000 can be improved, while ensuring that the flexible wheel 200 has a suitable deformation capacity.

[0077] Reference Figure 2 As shown, in the embodiment of the utility model, the tooth width Lf1 of the convex tooth 241 is smaller than the maximum length Lc of the inner tooth portion 110. It is understandable that the flexible wheel 200 has axial movement during operation, and due to the influence of processing errors, if the tooth width Lf1 of the convex tooth 241 is greater than the maximum length Lc of the inner tooth portion 110, it is easy to cause a part of the structure of the convex tooth 241 to be out of meshing state, affecting the stability of meshing. The harmonic reducer 1000 mainly checks the stability of the flexible wheel 200, so the tooth width Lf1 of the convex tooth 241 is designed to be smaller than the maximum length Lc of the inner tooth portion 110, which can improve the stability and reliability of the meshing of the flexible wheel 200.

[0078] Table 1: Comparison of tooth surface contact area of ​​different schemes

[0079]

[0080] For example, referring to Table 1 above, Scheme 1 is a scheme in the related art, Lc=0.42*Lf, Lf1=0.36*Lf, and the tooth height of the convex tooth 241 remains unchanged, that is, no tooth modification is used; Scheme 2 is Lc=0.55*Lf, Lf1=0.5*Lf, and the tooth height of the convex tooth 241 remains unchanged, that is, no tooth modification is used; Scheme 3 is a modification scheme in which Lc=0.55*Lf, Lf1=0.5*Lf, and the convex tooth 241 is provided with a first modification section 242 and a second modification section 244. It can be seen from Table 1 above that when Lc=0.55*Lf and Lf1=0.5*Lf are designed, the tooth surface contact area can be increased by 18.3%, and on this basis, the modification scheme is added, which increases the improvement by 32.6% compared with Scheme 1. The larger the tooth surface contact area, the smaller the contact stress, and the greater the load-bearing capacity of the harmonic reducer 1000.

[0081] Continue to refer to Figure 2 As shown, in the embodiment of the utility model, the second trimming section 244 is transitionally connected to the end of the flange portion 230 and the barrel portion 210 through an arc segment 260, and the arc segment 260 can be a circular arc segment. It can be understood that the scheme of transitional connection using the arc segment 260 can reduce the stress concentration phenomenon at the connection between the outer tooth portion 240 and the barrel portion 210. In the gear transmission process, this design can disperse the load, reduce stress concentration, and make the stress distribution more uniform, thereby improving the overall strength and durability of the flexible wheel 200. At the same time, it can simplify the processing process of the flexible wheel 200 and improve production efficiency.

[0082] Reference Figure 5As shown, in the embodiment of the utility model, the connection between the diaphragm 220 and the cylinder 210 is constructed as a corner portion 250, the inner side of the corner portion 250 is constructed as a first arc segment 251, and the outer side of the corner portion 250 is constructed as a second arc segment 252, so as to facilitate the processing and manufacturing of the flexible wheel 200 and improve the production efficiency. The outer side of the diaphragm 220 is constructed as a first segment 221, and the inner side of the diaphragm 220 is constructed as a second segment 222 and a first curved segment 223. It should be noted that the outer side of the diaphragm 220 refers to the side of the diaphragm 220 facing the outer tooth portion 240, and the inner side of the diaphragm 220 refers to the side of the diaphragm 220 away from the outer tooth portion 240. The two ends of the first curved segment 223 are respectively connected to the inner side of the flange portion 230 and the second segment 222, and the first curved segment 223 is composed of at least two arc segments, so as to facilitate the connection between the diaphragm 220 and the flange portion 230, and can reduce stress concentration, so as to improve the reliability and stability of the connection. Among them, the first segment 221 is a first straight segment 2211, and the second segment 222 is a second curved segment 2221, and the second curved segment 2221 is recessed in the direction of the first straight segment 2211. Therefore, in the direction away from the rotation axis, the thickness of the diaphragm 220 gradually decreases and then gradually increases, reducing the rigidity of the diaphragm 220 at the second curved segment 2221, which is beneficial to the deformation of the diaphragm 220, and can effectively reduce the stress concentration at both ends of the diaphragm 220 in the radial direction, reduce the risk of fracture, so as to improve the reliability and service life of the flexible wheel 200.

[0083] Reference Figure 6 As shown, in another embodiment of the utility model, the first section 221 is a second curved section 2221, and the second section 222 is a first straight section 2211. In the direction away from the rotation axis, the thickness of the diaphragm 220 can also be gradually reduced and then gradually increased, thereby effectively reducing the stress at both ends of the diaphragm 220 in the radial direction, and at the same time, it is beneficial to the deformation of the diaphragm 220 and improves the service life of the flexible wheel 200. The appropriate solution is selected according to the actual situation.

[0084] Reference Figure 7 and Figure 8As shown, in another embodiment of the utility model, the barrel portion 210 includes a first barrel section 211 and a second barrel section 212 connected to each other, the first barrel section 211 is connected to one end of the second barrel section 212 away from the flange portion 230, the second barrel section 212 is connected to the corner portion 250, and the outer tooth portion 240 is provided on the outer side wall of the first barrel section 211. The inner side of the second barrel section 212 is configured as a third section 2121, the third section 2121 is a third straight section 2125 and a third curved section 2124 connected to each other, and the third curved section 2124 is recessed toward the direction of the fourth section 2122; the outer side of the second barrel section 212 is configured as a fourth section 2122, and the fourth section 2122 is a second straight section 2123. Among them, the third curved section 2124 is closer to the corner portion 250 than the third straight section 2125, and the third curved section 2124 is composed of at least two arc sections, which can reduce stress concentration. It is understandable that, driven by the wave generator 300, the barrel portion 210 of the flexible wheel 200 will deform repeatedly, and the stress at the connection with the corner portion 250 is relatively large. Therefore, by arranging the third curved segment 2124 at a position close to the corner portion 250, the thickness of the second barrel segment 212 at the third curved segment 2124 can be made thinner, which is beneficial to the deformation of the barrel portion 210, thereby reducing the stress.

[0085] Reference Fig. 9 As shown, in another embodiment of the utility model, the third section 2121 is a second straight section 2123, the fourth section 2122 is a third straight section 2125 and a third curved section 2124 connected to each other, the third curved section 2124 is recessed toward the fourth section 2122, and the third curved section 2124 is closer to the corner 250 than the third straight section 2125. By arranging the third curved section 2124 at a position close to the corner 250, the thickness of the second barrel section 212 at the third curved section 2124 can be made thinner, which is beneficial to the deformation of the barrel 210, thereby reducing the stress.

[0086] Reference Figure 5 As shown, in the embodiment of the utility model, the effective length of the diaphragm 220 is Lf5, and the effective length refers to the shortest distance between the inner wall of the diaphragm 220 and the inner wall of the flange 230. The radial distances from point a, point b, point d, and point e of the diaphragm 220 to the end of the diaphragm 220 connected to the flange 230 are defined as La, Lb, Ld, and Le, respectively, wherein: La=0.02*Lf5; Lb=0.1*Lf5; Ld=0.45*Lf5; Le=0.86*Lf5; the wall thickness of the diaphragm 220 at point a, point b, point d, and point e are: ta, tb, td, te, respectively; the maximum wall thickness of the corner 250 is to, satisfying: td<tb<te≤to<ta≤2*td, that is, the diaphragm 220 is thick at both ends along the radial direction and thin in the middle.

[0087] It can be understood that point d is roughly located in the middle of the diaphragm 220, where the thickness is relatively thin, which can reduce the rigidity of the diaphragm 220 at this point, is conducive to the deformation of the diaphragm 220, and can effectively reduce the stress concentration at both ends of the diaphragm 220 along the radial direction, reduce the risk of fracture, and improve the reliability and service life of the flexible wheel 200. When td is less than tb, te, to, and ta, the stress at points a and o can be significantly reduced; when tb is less than te, and to is less than ta, the stress at points a and o can be further reduced to improve the reliability of the diaphragm 220. Point a is relatively close to the flange 230. In order to ensure the stability and reliability of the connection between the diaphragm 220 and the flange 230, ta≥to>te>tb>td is designed. When ta>2*td, the stress at point d will increase significantly, so it is necessary to design ta≤2*td to reduce the stress at point d.

[0088] Table 2: Comparison of stress values ​​of different schemes

[0089]

[0090] It should be noted that the solution of the related art in Table 2 is a case where the thickness of the diaphragm 220 is uniform, and the solution of this embodiment is td<tb<te≤to<ta≤2*td. It can be seen from Table 2 that after adopting the solution of this embodiment, the stress at points a, b, d, e and o are all reduced, which can improve the reliability and stability of the flexible wheel 200 and extend the service life of the flexible wheel 200.

[0091] Reference Figure 7 As shown, in the embodiment of the utility model, the minimum distance between the end wall of the cylinder 210 away from the flange portion 230 and the flange portion 230 is Lf, and the axial distances from the g point, h point, i point, j point, k point, and m point of the cylinder 210 to the outer wall of the flange portion 230 are defined as Lg, Lh, Li, Lj, Lk, and Lm, respectively. It should be noted that the outer wall of the flange portion 230 refers to the side of the flange portion 230 facing the external tooth portion 240. Wherein: Lg=0.04*Lf; Lh=0.10*Lf; Li=0.20*Lf; Lj=0.30*Lf; Lk=0.40*Lf; Lm=0.45*Lf; the wall thicknesses of the diaphragm 220 at points g, h, i, j, k and m are: tg, th, ti, tj, tk, tm respectively; the maximum wall thickness of the corner portion 250 is to; it satisfies: th≤tg<ti≤to<tj≤tk<tm.

[0092] It can be understood that the wall thickness of the barrel 210 from point o to point m is designed to be thick at both ends and thin in the middle, that is, th≤(tg, ti)≤(to, tj), which reduces the rigidity of the barrel 210 to reduce the stress at point o. When tg<ti and to<tj are designed, the stress at point o can be further reduced. When tj≤tk<tm is designed, it is beneficial to reduce the stress on the outer tooth portion 240.

[0093] Table 3: Comparison of stress values ​​of different schemes

[0094]

[0095] It should be noted that the solution of the related art in Table 3 is the case where the thickness of the barrel 210 is uniform, and the solution of this embodiment is th≤tg<ti≤to<tj≤tk<tm. As can be seen from Table 3, after adopting the solution of this embodiment, the stress at points o, g, h, i, j, k, and m are all reduced, which can improve the reliability and stability of the barrel 210 and extend the service life of the barrel 210.

[0096] An industrial robot according to an embodiment of the utility model can be a welding robot, a handling robot, a spraying robot, a processing robot, an assembly robot, etc. The industrial robot adopts the harmonic reducer of the above embodiment, and the wave generator 300 is coaxially installed in the inner hole of the flexible wheel 200, and the outer tooth portion 240 of the flexible wheel 200 is meshed with the inner tooth portion 110 of the rigid wheel 100, so that when the wave generator 300 rotates, it can drive the flexible wheel 200 and the rigid wheel 100 to rotate relative to each other. The outer tooth portion 240 is arranged on the cylinder portion 210 of the flexible wheel 200, and the cylinder portion 210 is also connected to the diaphragm portion 220, and the diaphragm portion 220 is connected to the flange portion 230. The outer tooth portion 240 includes a convex tooth 241. Since the convex tooth 241 is prone to interfere with the inner tooth portion 110 at both ends along the axial direction, the convex tooth 241 is provided to include a first shaping section 242, a middle section 243 and a second shaping section 244 connected in sequence, and the tooth height of the first shaping section 242 and the tooth height of the second shaping section 244 are gradually reduced in the direction away from the middle section 243, which can effectively reduce the interference between the convex tooth 241 and the inner tooth portion 110. At the same time, the ratio of the width of the first trimming section 242 to the width of the convex tooth 241 is reasonably designed to be between 0.2 and 0.35, the ratio of the width of the middle section 243 to the width of the convex tooth 241 is between 0.35 and 0.45, and the ratio of the width of the second trimming section 244 to the width of the convex tooth 241 is between 0.25 and 0.4. While ensuring the meshing stability of the convex tooth 241 and the inner tooth portion 110, the interference between the convex tooth 241 and the inner tooth portion 110 can be reduced, thereby reducing the friction and wear of the tooth surface, which is beneficial to extending the life of the flexible wheel 200.

[0097] Since the industrial robot of the embodiment of the utility model adopts all the technical solutions of the harmonic reducer 1000 of the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiment, which will not be repeated here.

[0098] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. Harmonic reducer, characterized in that: include: A rigid wheel having an internal tooth portion; A flexible wheel, comprising a cylinder, a diaphragm and a flange, wherein the cylinder is provided with an outer tooth portion cooperating with the inner tooth portion, the outer tooth portion is coaxially installed in the inner tooth portion, the diaphragm is connected to an end of the cylinder away from the outer tooth portion and extends to the outside of the cylinder, and the flange is connected to the outer peripheral edge of the diaphragm; a wave generator coaxially mounted on the inner hole of the flexspline, the wave generator being configured to mesh the outer tooth portion with the inner tooth portion when rotating; Wherein, the outer tooth portion includes a convex tooth arranged around the circumference of the barrel portion, and in the direction from the outer tooth portion to the flange portion, the convex tooth includes a first trimming segment, an intermediate segment and a second trimming segment connected in sequence, and the tooth height of the first trimming segment and the tooth height of the second trimming segment are gradually reduced in the direction away from the intermediate segment, respectively, and in the direction parallel to the rotation axis of the wave generator, the tooth width of the convex tooth is Lf1, the width of the first trimming segment is Lf2, the width of the intermediate segment is Lf3, and the width of the second trimming segment is Lf4, satisfying: 0.2*Lf1≤Lf2≤0.35*Lf1; 0.35*Lf1≤Lf3≤0.45*Lf1; 0.25*Lf1≤Lf4≤0.4*Lf1.

2. The harmonic reducer according to claim 1, characterized in that: The tooth top of the first trimming section is constructed as a first inclined surface inclined in a direction away from the middle section and toward the rotation axis, and the tooth top of the second trimming section is constructed as a second inclined surface inclined in a direction away from the middle section and toward the rotation axis, and the inclination angle of the second inclined surface is greater than the inclination angle of the first inclined surface.

3. The harmonic reducer according to claim 1, characterized in that: The tooth top of the first modified segment is configured as a first inclined surface inclined in a direction away from the middle segment and toward the rotation axis, and the inclination angle of the first inclined surface is α1, satisfying: 0.3°≤α1≤1°.

4. The harmonic reducer according to claim 3, characterized in that: The tooth top of the second modified segment is configured as a second inclined surface inclined in a direction away from the middle segment and toward the rotation axis, and the inclination angle of the second inclined surface is β1, satisfying: 0.3°≤β1≤1°, and β1≥α1.

5. The harmonic reducer according to claim 1, characterized in that: The minimum distance between the end wall of the cylinder away from the flange and the flange is Lf, and the maximum length of the inner tooth portion along the direction of the rotation axis is Lc, satisfying: 0.5*Lf≤Lc≤0.6*Lf.

6. The harmonic reducer according to claim 1, characterized in that: The minimum distance between the end wall of the barrel portion away from the flange portion and the flange portion is Lf, which satisfies: 0.45*Lf≤Lf1≤0.55*Lf.

7. The harmonic reducer according to claim 1, characterized in that: One end of the second trimming section facing the flange portion is transitionally connected to the cylinder portion via an arc section.

8. The harmonic reducer according to claim 1, characterized in that: The connection between the diaphragm and the cylinder is constructed as a corner portion, the inner side and the outer side of the corner portion are respectively constructed as a first arc segment and a second arc segment, the outer side of the diaphragm is constructed as a first section, the inner side of the diaphragm is constructed as a first curved segment and a second section, the two ends of the first curved segment are respectively connected to the inner side of the flange portion and the second section, the first curved segment is composed of at least two arc segments, one of the first segment and the second segment is a first straight line segment, and the other is a second curved segment, and the second curved segment is composed of at least one arc segment.

9. The harmonic reducer according to claim 1 or 8, characterized in that: The connection between the diaphragm and the cylinder is constructed as a corner portion, the cylinder includes a first cylinder section and a second cylinder section connected to each other, the external tooth portion is arranged on the first cylinder section, the inner side of the second cylinder section is constructed as a third section, and the outer side of the second cylinder section is constructed as a fourth section, one of the third section and the fourth section is a second straight line segment, and the other is a third straight line segment and a third curved segment connected to each other, the third curved segment is closer to the corner portion than the third straight line segment, and the third curved segment is composed of at least two circular arc segments.

10. The harmonic reducer according to claim 1, characterized in that: The effective length of the diaphragm is Lf5, and the radial distances from point a, point b, point d, and point e of the diaphragm to the end of the diaphragm connected to one end of the flange are La, Lb, Ld, and Le, respectively, wherein: La=0.02*Lf5; Lb=0.1*Lf5; Ld=0.45*Lf5; Le=0.86*Lf5; The wall thicknesses of the diaphragm at the point a, the point b, the point d, and the point e are ta, tb, td, and te respectively; The connection between the diaphragm and the cylinder is configured as a corner portion, and the maximum wall thickness of the corner portion is to; Satisfies: td<tb<te≤to<ta≤2*td.

11. The harmonic reducer according to claim 1 or 10, characterized in that: The minimum distance between the end wall of the barrel away from the flange and the flange is Lf, and the axial distances from the g, h, i, j, k, and m points of the barrel to the outer wall of the flange are defined as Lg, Lh, Li, Lj, Lk, and Lm, respectively, where: Lg=0.04*Lf; Lh=0.10*Lf; Li=0.20*Lf; Lj=0.30*Lf; Lk=0.40*Lf; Lm=0.45*Lf; The wall thicknesses of the barrel at the points g, h, i, j, k and m are tg, th, ti, tj, tk and tm respectively; The connection between the diaphragm and the cylinder is configured as a corner portion, and the maximum wall thickness of the corner portion is to; Satisfies: th≤tg<ti≤to<tj≤tk<tm.

12. An industrial robot, characterized in that: Including the harmonic reducer according to any one of claims 1 to 11.

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