CN223359836U

CN223359836U - Harmonic speed reducer and industrial robot

Info

Publication number: CN223359836U
Application number: CN202422865009.0U
Authority: CN
Inventors: 庄剑毅; 杨春龙; 张海祥; 何锐华
Original assignee: Guangdong Jiya Jingji Technology Co ltd
Current assignee: Guangdong Jiya Jingji Technology Co ltd
Priority date: 2024-11-22
Filing date: 2024-11-22
Publication date: 2025-09-19
Anticipated expiration: 2034-11-22

Abstract

The utility model discloses a harmonic speed reducer and an industrial robot, and relates to the technical field of speed reducers, wherein the harmonic speed reducer comprises a rigid gear, a flexible gear, a wave generator and a supporting bearing, the wave generator is positioned in the flexible gear, a first groove body and a second groove body are arranged between an inner bearing ring and an outer bearing ring of the supporting bearing, the first groove body is used for installing a first rolling body, and the second groove body is used for installing a second rolling body. Because the first installation department of rigid gear is connected in the middle part of internal tooth portion, and the first thin wall section and the second thin wall section of internal tooth portion are connected in the both ends of first installation department respectively, therefore first thin wall section and second thin wall section can produce the elastic deformation of certain degree. When the external tooth part is stressed too much, under the elastic deformation of the first thin-wall section and the second thin-wall section, the interference between the first thin-wall section and the second thin-wall section can be reduced, so that the vibration and noise of the harmonic reducer are reduced, the friction and abrasion of the flexible gear are reduced, and the service life of the flexible gear is prolonged.

Description

Harmonic speed reducer and industrial robot

Technical Field

The utility model relates to the technical field of speed reducers, in particular to a harmonic speed reducer and an industrial robot.

Background

In the related art, the harmonic reducer comprises a wave generator, a flexible gear and a rigid gear, wherein the wave generator is embedded in an inner hole of the flexible gear, and an external tooth part of the flexible gear is meshed with an internal tooth part of the rigid gear. The wave generator can drive different parts of the external tooth part and the internal tooth part to mesh when rotating, so that relative rotation is generated between the rigid gear and the flexible gear, and power output is realized. Because the flexspline is when receiving great pressure, the external tooth portion produces the interference with internal tooth portion along axial both ends easily, leads to wearing and tearing aggravation, vibration and noise increase, flexspline's life reduces.

Disclosure of utility model

The present utility model aims to solve at least one of the technical problems existing in the prior art. Therefore, the utility model provides the harmonic reducer which can reduce interference between the flexible gear and the rigid gear, reduce vibration and noise and prolong the service life of the flexible gear.

The utility model also provides an industrial robot with the harmonic reducer.

The harmonic reducer comprises a rigid gear, a flexible gear, a wave generator, a support bearing and an inner bearing ring, wherein the rigid gear comprises a first mounting part and an inner tooth part connected to the inner side of the first mounting part, the flexible gear is arranged in the rigid gear and comprises an outer tooth part, the wave generator is arranged in the flexible gear and is used for enabling the outer tooth part to be meshed with the inner tooth part, the support bearing is configured to enable the rigid gear and the flexible gear to rotate relatively, the support bearing comprises an outer bearing ring and an inner bearing ring arranged in the outer bearing ring, a first groove body used for being mounted by a first rolling body and a second groove body used for being mounted by a second rolling body are arranged between the inner bearing ring and the outer bearing ring, the first groove body and the second groove body are arranged at intervals along the axial direction of the wave generator, the first mounting part is connected with the inner bearing ring, the first mounting part is connected to the middle part of the inner tooth part, the first mounting part comprises a first thin-wall part and a second thin-wall part, the first thin-wall part is located towards the inner end of the first thin-wall part and the first thin-wall part is located towards the inner end of the first thin-wall part, and the first thin-wall part is located towards the inner end of the first thin-wall part of the first thin-wall section.

The harmonic reducer provided by the embodiment of the utility model has at least the following beneficial effects:

The wave generator is arranged inside the flexible gear, and the external tooth part of the flexible gear is meshed with the internal tooth part of the rigid gear, so that the flexible gear and the rigid gear can be driven to rotate relatively when the wave generator rotates. A first groove body and a second groove body are arranged between the inner bearing ring and the outer bearing ring of the support bearing, the first groove body is used for being installed by a first rolling body, the second groove body is used for being installed by a second rolling body, and the first groove body and the second groove body are arranged along the axial interval of the wave generator. Through setting up two sets of rolling bodies, can effectively promote the bearing capacity of harmonic speed reducer, when keeping complete machine structural compactness, promote the assembly efficiency between bearing device and rigid gear, the flexbile gear. Because the first installation department of rigid gear is connected in the middle part of internal tooth portion, and the first thin wall section and the second thin wall section of internal tooth portion are connected in the both ends of first installation department respectively, therefore first thin wall section and second thin wall section can produce the elastic deformation of certain degree. The external tooth part of the flexible gear is matched with the first thin-wall section and the second thin-wall section along the two ends of the axial direction respectively, when the external tooth part is stressed too much, the interference between the external tooth part and the first thin-wall section and between the external tooth part and the second thin-wall section can be reduced under the elastic deformation of the first thin-wall section and the second thin-wall section, so that the vibration and the noise of the harmonic reducer are reduced, the friction and the abrasion of the flexible gear are reduced, and the service life of the flexible gear is prolonged.

According to some embodiments of the utility model, the wave generator further comprises a flexible bearing connected to the inner bore of the flexible gear, the inner tooth portion has a width Lc, and a distance between a center line of the first mounting portion in the axial direction and a plane in which centers of all rolling elements of the flexible bearing are located is Lbc, so that Lbc is equal to or less than 0.1×lc.

According to some embodiments of the utility model, the width of the first thin-walled segment is Lc ₁, the width of the second thin-walled segment is Lc ₂, and the width of the internal tooth portion is Lc, in the axial direction, so that Lc is equal to or less than 0.6×lc ₁+Lc₂ and equal to or less than 0.9×lc.

According to some embodiments of the present utility model, the maximum wall thickness of the first thin-wall section is Tc ₁, the maximum wall thickness of the second thin-wall section is Tc ₂, and the inner hole diameter of the flexspline is Df, which is 0.015×df less than or equal to Tc ₁≤0.05*Df,0.015*Df≤Tc₂ ×less than or equal to 0.05×df.

According to some embodiments of the utility model, the connection between the first thin-walled segment and the first mounting portion is configured as a first curve, the first curve is composed of at least two circular arc segments, the first curve and the outer side of the first thin-walled segment are connected at a ₁ point, the first curve and the first mounting portion are connected at an e ₁ point, and a distance from the a ₁ point to the e ₁ point along the axial direction is Lwa ₁, so that 0.1×lc ₁≤Lwa₁≤0.3*Lc₁ is satisfied.

According to some embodiments of the utility model, the first curve has a point b ₁, a point c ₁ and a point d ₁, the distance from a ₁ point to a point b ₁ is Lwb ₁,b₁ to a point c ₁, the distance from Lwc ₁,c₁ to a point d ₁ is Lwd ₁,Lwb₁=Lwc₁=Lwd₁=Lwa₁/4, the maximum wall thickness of the first thin-wall section is Tc ₁, and the distances from a point b ₁, a point c ₁, a point d ₁, a point e ₁ and a point a ₁ along the radial direction of the rigid wheel are Lrb₁、Lrc₁、Lrd₁、Lre₁,Lrb₁＜Lrc₁＜Lrd₁＜Lre₁, ：0.1*Tc₁≤Lre₁≤0.4*Tc₁,Lrb₁+Lrc₁+Lrd₁≤Lre₁/2.

According to some embodiments of the utility model, the connection between the second thin-walled segment and the first mounting portion is configured as a second curve, the second curve is composed of at least two circular arc segments, the second curve and the outer side of the second thin-walled segment are connected at a ₂ point, the second curve and the first mounting portion are connected at an e ₂ point, and a distance from the a ₂ point to the e ₂ point along the axial direction is Lwa ₂, so that 0.1×lc ₁≤Lwa₂≤0.3*Lc₁ is satisfied.

According to some embodiments of the utility model, the second curve has a point b ₂, a point c ₂ and a point d ₂, the distance from a ₂ point to a point b ₂ is Lwb ₂,b₂ to a point c ₂, the distance from Lwc ₂,c₂ to a point d ₂ is Lwd ₂, Lwb₂=Lwc₂=Lwd₂=Lwa₂/4, the maximum wall thickness of the second thin-wall section is Tc ₂, and the distances from a point b ₂, a point c ₂, a point d ₂, a point e ₂ and a point a ₂ along the radial direction of the rigid wheel are Lrb₂、Lrc₂、Lrd₂、Lre₂,Lrb₂＜Lrc₂＜Lrd₂＜Lre₂, ：0.1*Tc₂≤Lre₂≤0.4*Tc₂,Lrb₂+Lrc₂+Lrd₂≤Lre₂/2.

According to some embodiments of the utility model, the flexible gear further comprises a cylinder, a diaphragm, and a flange, the external tooth is connected to the outside of one end of the cylinder, the diaphragm is connected to the other end of the cylinder and extends along the radial direction of the cylinder, the flange is connected to one end of the diaphragm away from the cylinder, and the flange and the external bearing ring are fixedly connected.

According to some embodiments of the utility model, the external tooth portion includes, in the axial direction, a first tooth segment distant from one end of the flange portion and a second tooth segment close to one end of the flange portion, a diameter of an addendum circle of the first tooth segment gradually decreasing in a direction away from the flange portion, and a diameter of an addendum circle of the second tooth segment gradually decreasing in a direction toward the flange portion.

According to some embodiments of the utility model, the external tooth system further comprises a third tooth segment located between the first tooth segment and the second tooth segment, the diameter of the tip circle of the third tooth segment being constant.

According to some embodiments of the utility model, the effective width of the flex gear is Lf, the width of the external teeth is Lf ₁, the width of the first tooth segment is Lf ₂, the width of the second tooth segment is Lf ₄, and the width of the third tooth segment is Lf ₃, in the axial direction, satisfying the following conditions ：0.4*Lf≤Lf₁≤0.6*Lf;0.2*Lf₁≤Lf₂≤0.35*Lf₁;0.35*Lf₁≤Lf₃≤0.45*Lf₁;0.25*Lf₁≤Lf₄≤0.4*Lf₁.

According to some embodiments of the utility model, the first thin-walled segment has a width Lc ₁ and the second thin-walled segment has a width Lc ₂, the inner tooth portion has a width Lc, the first tooth segment has an inclination angle alpha ₁, and the second tooth segment has an inclination angle beta ₁, in the axial direction, satisfying the following conditions ：0.2°-（Lc₂/Lc）*0.6°≤α₁≤0.8°-（Lc₂/Lc）*0.6°;0.3°-（Lc₁/Lc）*0.6°≤β₁≤0.9°-（Lc₁/Lc）*0.6°.

According to some embodiments of the utility model, the wall thickness of the tooth root of the flexible gear is Tf, the diameter of the inner hole of the flexible gear is Df, and the reduction ratio of the harmonic speed reducer is R, so that the reduction ratio is 0.0043ln (R) -0.0061 is less than or equal to Tf/Df is less than or equal to 0.005ln (R) -0.0036.

According to some embodiments of the utility model, the effective width of the flexible gear is Lf and the width of the internal tooth portion is Lc along the axial direction, which satisfies that Lf is 0.45×lc is 0.65×lf.

According to some embodiments of the utility model, the outer bearing ring comprises a second mounting part and a protruding part connected to the inner side of the second mounting part, wherein the protruding part is provided with a first outer raceway and a second outer raceway which are opposite to each other along the two ends of the axial direction respectively, the outer side of the inner bearing ring is provided with a groove which is opposite to the protruding part, the two ends of the groove along the axial direction respectively comprise a first inner raceway and a second inner raceway, the first inner raceway and the first outer raceway are opposite to each other and form the first groove body, and the second inner raceway and the second outer raceway are opposite to each other and form the second groove body.

According to some embodiments of the utility model, the inner bearing ring comprises a first ring body and a second ring body which are connected, the first inner raceway is arranged on the outer side of the first ring body and is close to the second ring body, the second inner raceway is arranged on the outer side of the second ring body and is far away from the first ring body, and the second ring body is connected with the rigid gear.

According to some embodiments of the utility model, the outer side of the first thin-wall section is abutted against the inner side of the second ring body, a protruding part is arranged on the second ring body in a protruding mode towards one end away from the first ring body, and the inner side of the protruding part is abutted against the outer side of the first mounting part.

An industrial robot according to an embodiment of the second aspect of the present utility model includes the harmonic reducer described in the above embodiment.

The industrial robot provided by the embodiment of the utility model has at least the following beneficial effects:

By adopting the harmonic reducer of the embodiment of the first aspect, the harmonic reducer is positioned inside the flexible gear by arranging the wave generator, and the external tooth part of the flexible gear is meshed with the internal tooth part of the rigid gear, so that the flexible gear and the rigid gear can be driven to rotate relatively when the wave generator rotates. A first groove body and a second groove body are arranged between the inner bearing ring and the outer bearing ring of the support bearing, the first groove body is used for being installed by a first rolling body, the second groove body is used for being installed by a second rolling body, and the first groove body and the second groove body are arranged along the axial interval of the wave generator. Through setting up two sets of rolling bodies, can effectively promote the bearing capacity of harmonic speed reducer, when keeping complete machine structural compactness, promote the assembly efficiency between bearing device and rigid gear, the flexbile gear. Because the first installation department of rigid gear is connected in the middle part of internal tooth portion, and the first thin wall section and the second thin wall section of internal tooth portion are connected in the both ends of first installation department respectively, therefore first thin wall section and second thin wall section can produce the elastic deformation of certain degree. The external tooth part of the flexible gear is matched with the first thin-wall section and the second thin-wall section along the two ends of the axial direction respectively, when the external tooth part is stressed too much, the interference between the external tooth part and the first thin-wall section and between the external tooth part and the second thin-wall section can be reduced under the elastic deformation of the first thin-wall section and the second thin-wall section, so that the vibration and the noise of the harmonic reducer are reduced, the friction and the abrasion of the flexible gear are reduced, and the service life of the flexible gear is prolonged.

Additional aspects and advantages of the utility model will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model.

Drawings

The utility model is further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic cross-sectional view of a harmonic reducer according to an embodiment of the present utility model;

FIG. 2 is a schematic cross-sectional view of a part of the structure of a flexspline and a rigid spline according to an embodiment of the present utility model;

FIG. 3 is a schematic view of a part of a rigid wheel according to an embodiment of the present utility model;

FIG. 4 is an enlarged view at B in FIG. 3;

FIG. 5 is an enlarged view at C in FIG. 3;

FIG. 6 is a schematic view of a part of a flexible gear according to an embodiment of the present utility model;

FIG. 7 is an enlarged view of FIG. 1 at A;

FIG. 8 is a schematic sectional view of a part of the structure of an external tooth part according to an embodiment of the present utility model;

FIG. 9 is a schematic sectional view showing a part of the structure of an external tooth part according to an embodiment of the present utility model;

FIG. 10 is a schematic view of the structure of an inner bearing ring according to an embodiment of the present utility model;

FIG. 11 is a cross-sectional view of an outer bearing ring according to one embodiment of the present utility model;

FIG. 12 is a graph of the ratio of (Lc ₁+Lc₂)/Lc versus torsional stiffness and vibration acceleration for one embodiment of the present utility model;

FIG. 13 is a graph of Tc ₁ and Df ratio versus rigid wheel stress and vibration acceleration for one embodiment of the utility model;

FIG. 14 is a plot of Tf/Df ratio versus root stress for a flexspline in accordance with one embodiment of the present utility model;

FIG. 15 is a graph showing the relationship between the ratio of Lbc/Lc and the vibration of the whole machine according to an embodiment of the present utility model;

FIG. 16 is a graph showing the relationship between the range of values of α ₁ and the vibration of the whole machine according to an embodiment of the present utility model;

Fig. 17 is a graph showing the relationship between the range of values of α ₂ and the vibration of the whole machine according to an embodiment of the present utility model.

Reference numerals:

A harmonic speed reducer 1000;

Rigid wheel 100, internal tooth portion 110, first thin-walled segment 111, second thin-walled segment 112, first mounting portion 120, first curve 130, second curve 140;

The flexible gear 200, the external tooth part 210, the first tooth segment 211, the first inclined plane 2111, the second inclined plane 2112, the second tooth segment 212, the third inclined plane 2121, the fourth inclined plane 2122, the third tooth segment 213, the barrel part 220, the diaphragm part 230 and the flange part 240;

Wave generator 300, cam 310, flexible bearing 320, third rolling element 321;

The support bearing 400, the outer bearing ring 410, the second mounting portion 411, the boss 412, the first outer raceway 413, the second outer raceway 414, the inner bearing ring 420, the boss 421, the groove 422, the first inner raceway 423, the second inner raceway 424, the first ring body 425, the second ring body 426, the first groove body 430, the first rolling element 431, the second groove body 440, the second rolling element 441;

and an oil seal 500.

Detailed Description

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the utility model.

In the description of the present utility model, it should be understood that the direction or positional relationship indicated with respect to the description of the orientation, such as up, down, etc., is based on the direction or positional relationship shown in the drawings, is merely for convenience of describing the present utility model and simplifying the description, and does not indicate or imply that the apparatus or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

In the description of the present utility model, plural means two or more. The description of the first and second is for the purpose of distinguishing between technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present utility model, unless explicitly defined otherwise, terms such as arrangement, installation, connection, etc. should be construed broadly and the specific meaning of the terms in the present utility model can be reasonably determined by a person skilled in the art in combination with the specific contents of the technical scheme.

Referring to fig. 1 and 2, a harmonic reducer 1000 according to an embodiment of the present utility model includes a flexspline 200, a rigid spline 100, and a wave generator 300. The flexspline 200 is coaxially mounted in the rigid spline 100, and the wave generator 300 is coaxially mounted in the inner bore of the flexspline 200. The flexible gear 200 includes a barrel 220, a diaphragm 230 and a flange 240, the barrel 220 is located at one end of the flexible gear 200 near the rigid gear 100, the diaphragm 230 is connected to one end of the barrel 220 far from the rigid gear 100 and extends radially to the barrel 220, and the flange 240 is connected to the outer periphery of the diaphragm 230. The tube portion 220 of the flexspline 200 is provided with flexible external teeth portions 210, and the external teeth portions 210 are radially outwardly protruded from the tube portion 220, and the external teeth portions 210 are formed not in the inner hole of the flexspline 200 but in the outer wall of the tube portion 220. The rigid gear 100 is provided with an internal gear portion 110, and an external gear portion 210 is engaged with the internal gear portion 110, and a meshing gap is formed between the external gear portion 210 and the internal gear portion 110.

In an embodiment of the present utility model, the wave generator 300 is connected to the inner hole of the flexspline 200 in an interference manner, and the wave generator 300 is configured to partially engage the external tooth portion 210 with the internal tooth portion 110 when rotated. The partial meshing means that the external tooth portion 210 of the flexspline 200 is deformed in the circumferential direction, and the partial structure in which the external tooth portion 210 is deformed meshes with the portion of the internal tooth portion 110 at the corresponding position, that is, the meshing position of the internal tooth portion 110 and the external tooth portion 210 is cyclically moved in the circumferential direction. When the wave generator 300 is installed in the inner hole of the flexible gear 200, the flexible gear 200 is forced to elastically deform and take an elliptical shape. In the operation process of the harmonic reducer 1000, the wave generator 300 rotates at a high speed to drive the flexspline 200 to deform repeatedly, so that the external tooth part 210 of the flexspline 200 meshes with the internal tooth part 110 of the rigid spline 100, and the meshing position of the external tooth part 210 and the internal tooth part 110 moves along the circumferential direction of the rotation axis of the wave generator 300, thereby realizing the relative deceleration motion between the flexspline 200 and the rigid spline 100. The wave generator 300 includes a flexible bearing 320 and a cam 310, the flexible bearing 320 is sleeved on the outer side of the cam 310, and the cam 310 is provided with a mounting position for connecting a driving device such as a motor.

Referring to fig. 1, the harmonic reducer 1000 according to an embodiment of the present utility model further includes a support bearing 400, and the support bearing 400 is configured to enable the rigid gear 100 and the flexible gear 200 to rotate relative to each other. The support bearing 400 includes a first rolling element 431, a second rolling element 441, an outer bearing ring 410, and an inner bearing ring 420 disposed in the outer bearing ring 410, wherein an annular first groove 430 and an annular second groove 440 are disposed between the inner bearing ring 420 and the outer bearing ring 410, along the axial direction of the wave generator 300, and the first groove 430 is located at a side far from the rigid wheel 100, the second groove 440 is located at a side near the rigid wheel 100 and spaced from the first groove 430, i.e. the first groove 430 is located at the left side of the harmonic reducer 1000, and the second groove 440 is located at the right side of the harmonic reducer 1000. The first rolling element 431 is provided in plurality and is mounted on the first groove 430, and the second rolling element 441 is provided in plurality and is mounted on the second groove 440. The inner bearing ring 420 and the rigid gear 100 are fixedly connected, and the outer bearing ring 410 and the flange portion 240 of the flexible gear 200 are fixedly connected by fastening means (such as screws, bolts, pins, etc.), or by fastening means, bonding means, etc. The relative rotation of flexspline 200 and rigid spline 100 is thus facilitated by the cooperation of first rolling elements 431, second rolling elements 441, inner bearing ring 420 and outer bearing ring 410.

By adopting two sets of the plurality of first rolling elements 431 and the plurality of second rolling elements 441, the bearing capacity of the bearing device can be improved relative to the single-row crossed roller bearing in the related art, and the configuration of the inner bearing ring 420 and the outer bearing ring 410 is matched to facilitate the assembly of the harmonic reducer 1000, and the adaptation to different loads is easier. It is understood that the first rolling element 431 may be a sphere, or a cylinder, a cone, or the like, and the second rolling element 441 may be a sphere, or a cylinder, a cone, or the like, which are not particularly limited herein. In addition, in the present embodiment, the first rolling bodies 431 and the second rolling bodies 441 may be made of a metal material such as steel.

When the flexspline 200 is not mounted to the wave generator 300, the inner hole is circular, and when the flexspline 200 and the wave generator 300 are assembled, the external teeth portion 210 of the flexspline 200 becomes elliptical. Due to the structural relationship of the flexspline 200, the outer teeth 210 have different amounts of deformation in different sections in the axial direction, and the amount of deformation increases as the outer teeth come closer to the opening of the cylindrical portion 220. In general, the meshing state of the intermediate tooth segments of the external tooth portion 210 in the axial direction is optimal, and the tooth segments near one end of the flange portion 240 easily interfere with the tooth tips of the internal tooth portion 110 of the rigid gear 100 or have too small a clearance, thereby generating abnormal frictional wear and noise, and the tooth segments far from one end of the flange portion 240 easily interfere with the tooth roots or the intermediate portion of the internal tooth portion 110 of the rigid gear 100, thereby generating abnormal frictional wear and noise.

To solve the above problem, referring to fig. 3, in the embodiment of the present utility model, the rigid wheel 100 further includes a first mounting portion 120, and the internal tooth portion 110 is connected to the inner side of the first mounting portion 120. The first mounting portion 120 is coupled to the inner bearing ring 420 by fasteners, such as screws, bolts, pins, or the like. Along the axial direction of the wave generator 300, the first mounting portion 120 is connected to the middle portion of the internal tooth portion 110, and the connection manner may be integrally formed, welded, or the like. The middle portion of the internal tooth portion 110 means that the end portion of the first mounting portion 120 does not overlap with the end portion of the internal tooth portion 110 in the axial direction of the wave generator 300, i.e., in the left-right direction in fig. 3, nor protrudes outward from the end portion of the internal tooth portion 110, i.e., the position between the axial ends of the internal tooth portion 110 belongs to the middle portion of the internal tooth portion 110. The first attachment portion 120 may be connected to the middle portion of the internal gear portion 110, but may be connected to the middle portion without being connected to the left end portion and the right end portion, or may be connected to the middle portion, the left end portion, and the right end portion together with the first attachment portion 120, or may be connected to the middle portion and one of the left end portion and the right end portion. And selecting a proper connection mode according to actual conditions.

With continued reference to fig. 3, the internal tooth portion 110 includes a first thin-walled segment 111 and a second thin-walled segment 112, the first thin-walled segment 111 is located at an end of the first mounting portion 120 facing the inner bearing ring 420, an outer side of the first thin-walled segment 111 abuts an inner side of the inner bearing ring 420, and the second thin-walled segment 112 is located at an end of the first mounting portion 120 facing away from the inner bearing ring 420. That is, the first thin-walled segment 111 is connected to the left end of the first mounting portion 120, and the second thin-walled segment 112 is connected to the right end of the first mounting portion 120.

With the above-mentioned scheme, since the first mounting portion 120 of the rigid gear 100 is connected to the middle portion of the internal gear 110, and the first thin-walled segment 111 and the second thin-walled segment 112 of the internal gear 110 are respectively connected to two ends of the first mounting portion 120 in the axial direction, the first thin-walled segment 111 and the second thin-walled segment 112 can be elastically deformed to a certain extent. The two ends of the external tooth part 210 of the flexible gear 200 along the axial direction are respectively matched with the first thin-wall section 111 and the second thin-wall section 112, when the external tooth part 210 is stressed too much, interference with the first thin-wall section 111 and the second thin-wall section 112 can be reduced under the elastic deformation of the first thin-wall section 111 and the second thin-wall section 112, so that vibration and noise of the harmonic reducer 1000 are reduced, frictional wear of the flexible gear 200 is reduced, and the service life of the flexible gear 200 is prolonged. Meanwhile, since interference between the external tooth part 210 and the internal tooth part 110 is reduced, the mounting accuracy requirement for the rigid gear 100 is reduced, and the production yield of the harmonic reducer 1000 is improved.

Referring to fig. 2, in the embodiment of the present utility model, the inner tooth portion 110 has a width Lc, the first mounting portion 120 has a center line L in the axial direction, and the center line L extends in the radial direction of the wave generator 300. The plane in which the centers of all the third rolling elements 321 of the compliant bearing 320 are located is S, which is also disposed along the radial extension of the wave generator 300 and is parallel to the center line L. The distance between the central line L and the plane S is Lbc, which is less than or equal to 0.1 x Lc, and the formula is equivalent to Lbc/Lc which is less than or equal to 0.1, for example, the values of Lbc/Lc can be 0.1, 0.05, 0.01, 0, -0.05, -0.15 and the like.

Referring to fig. 15, the abscissa in fig. 15 represents the value range Lbc/Lc, and the ordinate represents the magnitude of the entire vibration of the harmonic reducer 1000. As can be seen from fig. 15, as Lbc/Lc gradually increases, the overall vibration decreases and then increases, and the overall vibration at lbc=0 is smallest, that is, the closer the distance between the center line L and the plane S of the first mounting portion 120 is, the better, and the center line L may coincide with the plane S. The width Lc of the internal tooth 110 is generally fixed, and when Lbc is greater than 0.1×lc, the length of the first thin-walled segment 111 is too long, which is prone to deformation and bending, and the length of the second thin-walled segment 112 is too short, which is difficult to have an elastic deformation effect. Or the first thin-walled segment 111 is too short in length to have an elastic deformation effect, and the second thin-walled segment 112 is too long in length to be easily deformed and bent. Therefore, the distance between the center line L and the plane S is less than 0.1×lc, which is beneficial for the wave generator 300 to support the rigid wheel 100, so as to improve the bearing capacity of the harmonic reducer 1000 and reduce the vibration and noise of the whole machine.

Referring to fig. 3, in the embodiment of the present utility model, the width of the first thin-walled segment 111 is Lc ₁ and the width of the second thin-walled segment 112 is Lc ₂ along the axial direction of the wave generator 300. The width Lc ₁ of the first thin-walled segment 111 refers to the maximum distance between the left end surface of the first mounting portion 120 and the left end surface of the first thin-walled segment 111. The width Lc ₂ of the second thin-walled segment 112 refers to the maximum distance between the right end face of the first mounting portion 120 and the right end face of the second thin-walled segment 112. The width of the internal tooth portion 110 is Lc, and the width of the internal tooth portion 110 refers to the maximum distance between the left end face and the right end face of the internal tooth portion 110. The width Lc of the internal tooth 110, the width Lc ₁ of the first thin-walled segment 111, and the width Lc ₂ of the second thin-walled segment 112 satisfy 0.6×lc+. ₁+Lc₂ ×ζ≤0.9×lc. This formula is equivalent to 0.6≤Lc ₁+Lc₂/Lc≤0.9, for example the value of (Lc ₁+Lc₂)/Lc may be 0.6, 0.65, 0.7, 0.8, 0.85, 0.9 etc.

Referring to fig. 12, the abscissa of fig. 12 represents the value of (Lc ₁+Lc₂)/Lc, the ordinate on the left side represents torsional rigidity, and the ordinate on the right side represents vibration acceleration. Torsional stiffness refers to the slope of a line segment taken on a mechanical hysteresis loop, expressed as the amount of torque change per unit of torsion angle, and describes the ratio between the relative torsion angle due to elastic deformation and the load. The greater the torsional rigidity, the smaller the torsion angle of the output shaft is generated when the output shaft is subjected to external force, and the higher the positioning accuracy is. The vibration acceleration refers to acceleration generated by vibration phenomena caused by various internal and external factors in the running process of the speed reducer, and reflects stability and smoothness of the speed reducer in dynamic running. The smaller vibration acceleration means that the harmonic speed reducer 1000 is more stable and smooth in the operation process, which is helpful for reducing the abrasion and energy loss of the harmonic speed reducer 1000, improving the overall performance and service life of the speed reducer.

As is clear from fig. 12, when the value of (Lc ₁+Lc₂)/Lc is smaller than 0.6, the torsional rigidity is high, but the vibration acceleration of the harmonic speed reducer 1000 is large, and the running stability is poor. When the value of (Lc ₁+Lc₂)/Lc is greater than 0.9, the torsional rigidity is also small although the vibration acceleration is small. Therefore, the value of (Lc ₁+Lc₂)/Lc is reasonably designed within the range of 0.6 to 0.9, so that the vibration acceleration of the harmonic speed reducer 1000 can be reduced, the running stability of the harmonic speed reducer 1000 can be improved, and meanwhile, the torsional rigidity can be ensured to be in a proper size, so that the torsion resistance and the positioning accuracy of the harmonic speed reducer 1000 can be improved.

Referring to fig. 1 and 3, in the embodiment of the present utility model, the maximum wall thickness of the first thin-walled segment 111 is Tc ₁, and the maximum wall thickness of the second thin-walled segment 112 is Tc ₂. The maximum wall thickness Tc ₁ of the first thin-walled segment 111 and the maximum wall thickness Tc ₂ of the second thin-walled segment 112 refer to the maximum thicknesses of the first thin-walled segment 111 and the second thin-walled segment 112 in the radial direction of the wave generator 300. The inner hole diameter of the flexible gear 200 is Df, which is 0.015 x Df is less than or equal to Tc ₁≤0.05*Df,0.015*Df≤Tc₂ and less than or equal to 0.05 x Df. Wherein, the formula is equivalent to that Tc ₁/Df≤0.05,0.015≤Tc₂/Df is less than or equal to 0.015 and less than or equal to 0.05. Wherein the Tc ₁/Df can be 0.015, 0.02, 0.03, 0.04 and 0.05, and the Tc ₂/Df can be 0.015, 0.02, 0.03, 0.04 and 0.05.

Referring to fig. 13, the abscissa in fig. 13 represents the value of Tc ₁/Df, the ordinate on the left side represents the magnitude of stress received by the rigid wheel 100, and the ordinate on the right side represents the vibration acceleration of the harmonic speed reducer 1000. Since the values of Tc ₁/Df and Tc ₂/Df are equal in this embodiment, FIG. 13 can also be used to show the relationship between the values of Tc ₂/Df, vibration acceleration, and stress of the rigid wheel 100. As can be seen from fig. 13, when Tc ₁/Df and Tc ₂/Df are smaller than 0.015, the vibration acceleration of the harmonic reducer 1000 is low, but the stress of the rigid wheel 100 is large, and the load bearing capacity of the rigid wheel 100 is reduced. When the values of Tc ₁/Df and Tc ₂/Df are larger than 0.05, the stress of the rigid wheel 100 is smaller, but the vibration acceleration of the harmonic reducer 1000 is larger, and the running is unstable. Therefore, by reasonably designing when the values of Tc ₁/Df and Tc ₂/Df are in the range of 0.015 to 0.05, the vibration acceleration can be reduced to improve the running stability of the harmonic speed reducer 1000, and the stress of the rigid wheel 100 can be reduced to improve the bearing capacity of the rigid wheel 100.

Referring to fig. 4, in the embodiment of the present utility model, the first curve 130 is connected to the outside of the first thin-walled segment 111 at point a ₁, and the first curve 130 is connected to the first mounting portion 120 at point e ₁. Along the axial direction of the wave generator 300, the distance from the point a ₁ to the point e ₁ is Lwa ₁, satisfying 0.1 lc ₁≤Lwa₁≤0.3*Lc₁. This formula is equivalent to 0.1≤ Lwa ₁/Lc₁≤0.3, for example Lwa ₁/Lc₁ may take on values of 0.1, 0.15, 0.2, 0.25, 0.3 etc. The above formula reflects the range of the duty ratio of the first curve 130 in the axial direction of the first thin-walled segment 111. When Lwa ₁/Lc₁ has a value smaller than 0.1, that is, the length of the first curve 130 in the axial direction is shorter, it is difficult to reduce the stress at the connection between the first mounting portion 120 and the first thin-wall section 111. When Lwa ₁/Lc₁ has a value greater than 0.3, the length of the first curve 130 along the axial direction is too long, which is not beneficial to the abutting fit of the inner bearing ring 420 and the outer wall of the first thin-wall section 111, and affects the fit precision. Therefore, by reasonably designing Lwa ₁/Lc₁ to take a value in the range of 0.1 to 0.3, the stress of the first thin-walled segment 111 and the first mounting portion 120 at the joint can be reduced while the abutting and matching precision of the inner bearing ring 420 and the first thin-walled segment 111 is ensured, so that the stress concentration condition is reduced, and the bearing capacity of the rigid wheel 100 can be improved.

Referring to FIG. 4, in an embodiment of the present utility model, the first curve 130 has a point b ₁, At points c ₁ and d ₁, at a distance from point a ₁ to point b ₁ from point Lwb ₁,b₁ to point c ₁, at a distance from point Lwc ₁,c₁ to point d ₁, and at a distance of Lwd ₁,Lwb₁=Lwc₁=Lwd₁=Lwa₁/4, the first curve 130 is axially divided into four halves. Along the radial direction of the rigid wheel 100, the point b ₁, the point c ₁, the point d ₁, The distance between the point e ₁ and the point a ₁ is Lrb₁、Lrc₁、Lrd₁、Lre₁,Lrb₁＜Lrc₁＜Lrd₁＜Lre₁,, and the Tc is 0.1 times less than or equal to Lre ₁≤0.4*Tc,Lrb₁+Lrc₁+Lrd₁≤Lre₁/2. Wherein, 0.1×Tc is equal to or less than Lre ₁ and equal to or less than 0.4×Tc is equal to or less than 0.1 and equal to or less than Lre ₁/Tc and is equal to or less than 0.4, for example, the value of Lre ₁/Tc can be 0.1, 0.2, 0.3, 0.4 and the like. It is understood that when Lre ₁/Tc is less than 0.1 and Lrb ₁+Lrc₁+Lrd₁＞Lre₁/2, that is, the height of the first curve 130 in the radial direction of the rigid wheel 100 is low, it is difficult to perform a smooth transition function at the junction of the first thin-walled segment 111 and the first mounting portion 120, and the effect of reducing stress concentration is not obvious. When Lre ₁/Tc is greater than 0.4, i.e., the height of the first curve 130 in the radial direction of the rigid wheel 100 is higher, the abutment fit of the inner bearing ring 420 with the first thin-walled segment 111 is not facilitated. Therefore, by reasonably designing the value of Lre ₁/Tc to be in the range of 0.1 to 0.4 and Lrb ₁+Lrc₁+Lrd₁≤Lre₁/2, the phenomenon of stress concentration at the joint of the first thin-wall section 111 and the first mounting part 120 can be effectively reduced, meanwhile, the abutting fit of the inner bearing ring 420 and the first thin-wall section 111 is facilitated, and the mounting efficiency is improved.

TABLE 1 maximum stress contrast at the connection of the first thin-walled segment 111 and the first mounting portion 120 for three different scenarios

In table 1, the scheme 1 is a scheme in which the first mounting portion 120 and the first thin-walled segment 111 are directly connected without providing the first curve 130, the scheme 2 is a scheme in which the first mounting portion 120 and the first thin-walled segment 111 are connected through a straight line segment, and the scheme 3 is a scheme of the present embodiment, that is, a scheme in which the first curve 130 is provided to connect the first mounting portion 120 and the first thin-walled segment 111. As is clear from the above table, the maximum stress when the first mounting portion 120 and the first thin-walled segment 111 were directly connected was 222MPa, while when the first mounting portion 120 and the second thin-walled segment 112 were connected by a straight line segment, the maximum stress was 198MPa, and the maximum stress in the case of the embodiment 2 was reduced by 10.8% compared with that in the case of the embodiment 1. In the case of the present embodiment, the maximum stress was 172MPa, which is 22.5% lower than that of the case 1. Therefore, the solution of the present embodiment can effectively reduce the maximum stress of the first thin-wall section 111 and the first mounting portion 120 at the connection position, and effectively avoid the phenomenon of stress concentration, so as to improve the bearing capacity of the rigid wheel 100.

Referring to fig. 4, in the embodiment of the present utility model, the outer side of the second curved line 140 and the second thin-walled segment 112 is connected to the point a ₂, and the second curved line 140 and the first mounting portion 120 are connected to the point e ₂. Along the axial direction of the wave generator 300, the distance from the point a ₂ to the point e ₂ is Lwa ₂, satisfying 0.1 lc ₂≤Lwa₂≤0.3*Lc₂. This formula is equivalent to 0.1≤ Lwa ₂/Lc₂≤0.3, for example Lwa ₂/Lc₂ may take on values of 0.1, 0.15, 0.2, 0.25, 0.3 etc. The above formula reflects the range of the duty cycle of the second curve 140 in the axial direction of the second thin-walled segment 112. When Lwa ₂/Lc₂ has a value smaller than 0.1, that is, the length of the second curve 140 in the axial direction is shorter, it is difficult to reduce the stress at the junction between the first mounting portion 120 and the second thin-walled segment 112. When Lwa ₂/Lc₂ has a value greater than 0.3, the axial length of the second curve 140 is too long, which is not conducive to deformation of the second thin-walled segment 112. Therefore, by reasonably designing Lwa ₂/Lc₂ to have a value in the range of 0.1 to 0.3, the stress at the connection between the second thin-walled segment 112 and the first mounting portion 120 is reduced, so that the stress concentration is reduced, and the bearing capacity of the rigid wheel 100 can be improved.

Referring to FIG. 5, in an embodiment of the present utility model, the second curve 140 has a point b ₂, at points c ₂ and d ₂, at a distance from point a ₂ to point b ₂ from point Lwb ₂,b₂ to point c ₂, at a distance from point Lwc ₂,c₂ to point d ₂, and at a distance of Lwd ₂,Lwb₂=Lwc₂=Lwd₂=Lwa₂/4, the second curve 140 is axially divided by four. Along the radial direction of the rigid wheel 100, the point b ₂, the point c ₂, the point d ₂, The distance between the point e ₂ and the point a ₂ is Lrb₂、Lrc₂、Lrd₂、Lre₂,Lrb₂＜Lrc₂＜Lrd₂＜Lre₂,, and the Tc is 0.1 times less than or equal to Lre ₂≤0.4*Tc,Lrb₂+Lrc₂+Lrd₂≤Lre₂/2. Wherein, 0.2×Tc is equal to or less than Lre ₂ and equal to or less than 0.4×Tc is equal to or less than 0.1 and equal to or less than Lre ₂/Tc and is equal to or less than 0.4, for example, the value of Lre ₂/Tc can be 0.1, 0.2, 0.3, 0.4 and the like. It will be appreciated that when Lre ₂/Tc is less than 0.1 and Lrb ₂+Lrc₂+Lrd₂＞Lre₂/2, i.e., the height of the second curve 140 in the radial direction of the rigid wheel 100 is low and close to right angles, it is difficult to perform a smooth transition at the junction of the second thin-walled segment 112 and the first mounting portion 120, and the effect of reducing stress concentration is not obvious. When Lre ₂/Tc is greater than 0.4, the height of the second curve 140 in the radial direction of the rigid wheel 100 is high, which is disadvantageous for the deformation of the second thin-walled segment 112. Therefore, by reasonably designing the value of Lre ₂/Tc to be in the range of 0.1 to 0.4 and Lrb ₂+Lrc₂+Lrd₂≤Lre₂/2, the phenomenon of stress concentration at the joint of the second thin-wall section 112 and the first mounting portion 120 can be effectively reduced, and the service life of the rigid wheel 100 can be prolonged.

TABLE 2 maximum stress contrast at the connection of the second thin-walled segment 112 and the first mounting portion 120 for three different scenarios

In table 2, the scheme 1 is a scheme in which the first mounting portion 120 and the second thin-walled segment 112 are directly connected without providing the second curve 140, the scheme 2 is a scheme in which the first mounting portion 120 and the second thin-walled segment 112 are connected through a straight line segment, and the scheme 3 is a scheme of the present embodiment, that is, a scheme in which the second curve 140 is provided to connect the first mounting portion 120 and the second thin-walled segment 112. As is clear from the above table, the maximum stress when the first mounting portion 120 and the second thin-walled segment 112 were directly connected was 198MPa, while when the first mounting portion 120 and the second thin-walled segment 112 were connected by a straight line segment, the maximum stress was 179MPa, and the maximum stress in the case of the embodiment 2 was reduced by 9.1% compared with that in the case of the embodiment 1. In the case of the present embodiment, the maximum stress was 166MPa, which is 15.7% lower than that of the case 1. Therefore, the scheme of the embodiment can effectively reduce the maximum stress of the connection between the second thin-wall section 112 and the first mounting portion 120, and effectively avoid the phenomenon of stress concentration, so as to improve the bearing capacity of the rigid wheel 100.

Referring to fig. 7, in the embodiment of the present utility model, the portion of the inner tooth portion 110 protruding from the first mounting portion 120 in the axial direction abuts against the inner side of the inner bearing ring 420, so that the inner bearing ring 420 plays a role in supporting the inner tooth portion 110, and bending deformation of the inner tooth portion 110 at a large angle due to excessive stress is avoided, so as to improve the reliability of the rigid gear 100. The inner bearing ring 420 is provided with a protruding portion 421 at one end in the axial direction, the protruding portion 421 protrudes toward the first mounting portion 120, and the inner side of the protruding portion 421 abuts against the outer side of the first mounting portion 120. It will be appreciated that the provision of the tab 421 may act as a location for the mounting of the rigid wheel 100. At the same time, the protrusions 421 also facilitate the installation of the oil seal 500 between the inner bearing ring 420 and the outer bearing ring 410. The oil seal 500 is annular and is arranged concentrically with the outer bearing ring 410, the outer side of the oil seal 500 is in interference fit with the inner hole of the outer bearing ring 410, and the inner hole of the oil seal 500 is in sealing fit with the outer wall of the protruding part 421, so that the sealing effect is improved. The inner bearing ring 420 and the oil seal 500 can also form radial contact seal when relatively rotating, thereby effectively avoiding the lubricating material in the first groove body 430 and the second groove body 440 from overflowing to the rigid wheel 100.

Referring to fig. 8, in the embodiment of the present utility model, the external gear part 210 includes a plurality of teeth arranged along the circumferential direction of the flexspline 200 and protruding outward, the plurality of teeth includes a first tooth segment 211, a second tooth segment 212, and a third tooth segment 213 extending in the axial direction, and the first tooth segment 211, the third tooth segment 213, and the second tooth segment 212 are sequentially connected in a direction from the external gear part 210 to the flange part 240, i.e., in a right-to-left direction in fig. 7. The tip circle diameter of the first tooth segment 211 gradually decreases in a direction away from the flange portion 240, and the tip circle diameter of the second tooth segment 212 gradually decreases in a direction toward the flange portion 240. That is, the first tooth segment 211 and the second tooth segment 212 adopt a tooth modification scheme, and the tooth heights of the first tooth segment 211 and the second tooth segment 212 are gradually reduced along the direction away from the third tooth segment 213, respectively, and refer to the heights along the radial direction. For example, the tooth tips of the first tooth segment 211 and the second tooth segment 212 may be inclined in a straight direction, or may be convex arcs, concave arcs, or the like. By providing the first tooth segment 211 and the second tooth segment 212 with gradually decreasing tooth heights, the occurrence of interference between the tooth tops of the first tooth segment 211 and the second tooth segment 212 and the internal tooth portion 110 can be effectively reduced, so as to improve the service life of the flexspline 200.

With continued reference to fig. 8, in the embodiment of the present utility model, the diameter of the tip circle of the third tooth segment 213 is constant, i.e., the tooth height of the third tooth segment 213 remains unchanged. Because the flexible gear 200 has an opening angle after the cylindrical portion 220 becomes elliptical under the action of the wave generator 300, the movement tracks of the external tooth portions 210 under different cross sections are different, the state of the third tooth segment 213 is optimal in the middle portion of the external tooth portion 210, and interference phenomenon is not easy to occur, and interference between the external tooth portion 210 and the internal tooth portion 110 is easy to occur at two ends of the external tooth portion along the axial direction. For this purpose, the tooth heights of the first tooth segment 211 and the second tooth segment 212 are designed to be respectively gradually reduced in the direction away from the third tooth segment 213, so that the occurrence of interference between the tooth tops of the first tooth segment 211 and the second tooth segment 212 and the internal tooth 110 can be effectively reduced.

Referring to fig. 2 and 9, in the embodiment of the present utility model, in the direction parallel to the rotation axis of the wave generator 300, the effective width of the flexspline 200 is Lf, the tooth width of the external tooth portion 210 is Lf ₁, so that the value of Lf ₁ is 0.4×lf and Lf is 0.6×lf, for example, the value of Lf ₁ may be 0.4×lf, 0.45×lf, 0.5×lf, 0.55×lf, and 0.6×lf. The first tooth segment 211 has a width Lf ₂, which satisfies a value of 0.2×lf ₁≤Lf₂≤0.35*Lf₁, for example Lf ₂, may be 0.2*Lf₁、0.23*Lf₁、0.24*Lf₁、0.25*Lf₁、0.3*Lf₁、0.35*Lf₁., the third tooth segment 213 has a width Lf ₃, which satisfies a value of 0.35×lf ₁≤Lf₃≤0.45*Lf₁, for example Lf ₃, may be 0.35*Lf₁、0.38*Lf₁、0.39*Lf₁、0.40*Lf₁、0.42*Lf₁、0.45*Lf₁., the second tooth segment 212 has a width Lf ₄, which satisfies a value of 0.25×lf ₁≤Lf₄≤0.4*Lf₁, for example Lf ₄, may be 0.25*Lf₁、0.28*Lf₁、0.3*Lf₁、0.35*Lf₁、0.38*Lf₁、0.4*Lf₁.

It will be appreciated that the width of the first tooth segment 211, the third tooth segment 213 and the second tooth segment 212 will affect the meshing effect with the inner tooth 110. When Lf ₁ is less than 0.4×lf, the tooth width of the external tooth portion 210 is short, the effective meshing area of the external tooth portion 210 and the internal tooth portion 110 is reduced, and stability at the time of meshing is deteriorated. When Lf ₁ is greater than 0.6xlf, the tooth width of the external tooth portion 210 is longer, and the volume of the harmonic accelerator is increased, which is not beneficial to compact design. When Lf ₂ is less than 0.2×lf ₁, i.e., the width of the first tooth segment 211 is smaller, interference with the internal tooth portion 110 is easily generated. When Lf ₂ is greater than 0.4×lf ₁, i.e. the width of the first tooth segment 211 is greater, in the case where the width of the external tooth portion 210 remains unchanged, the width of the third tooth segment 213 needs to be correspondingly shortened, so that the effective meshing area of the external tooth portion 210 and the internal tooth portion 110 is reduced, and stability during meshing is degraded. When Lf ₃ is less than 0.35×lf ₁, i.e., the width of the third tooth segment 213 is smaller, the effective meshing area of the external tooth portion 210 and the internal tooth portion 110 is also reduced, and the stability at the time of meshing is deteriorated. When Lf ₃ is greater than 0.45×lf ₁, the widths of the first tooth segment 211 and the second tooth segment 212 need to be correspondingly reduced while the width of the external tooth portion 210 remains unchanged, and interference is easily generated between the first tooth segment 211 and the second tooth segment 212 and the internal tooth portion 110. When Lf ₄ is less than 0.25×lf ₁, i.e., the width of the second tooth segment 212 is small, interference with the internal tooth 110 is easily generated. When Lf ₄ is greater than 0.45×lf ₁, that is, the width of the second tooth segment 212 is greater, the width of the third tooth segment 213 needs to be correspondingly shortened when the width of the external tooth portion 210 is kept unchanged, so that the effective meshing area of the external tooth portion 210 and the internal tooth portion 110 is reduced, and stability during meshing is poor.

Therefore, the ratio of the tooth width of the external tooth portion 210 to the effective width of the flexible gear 200 is reasonably designed to be between 0.4 and 0.6, the ratio of the width of the first tooth segment 211 to the width of the external tooth portion 210 is in the range of 0.2 to 0.35, the ratio of the width of the third tooth segment 213 to the width of the external tooth portion 210 is in the range of 0.35 to 0.45, and the ratio of the width of the second tooth segment 212 to the width of the external tooth portion 210 is in the range of 0.25 to 0.4, so that the meshing stability of the external tooth portion 210 and the internal tooth portion 110 can be ensured, the interference between the external tooth portion 210 and the internal tooth portion 110 can be reduced, the frictional wear of tooth surfaces can be reduced, and the service life of the flexible gear 200 can be prolonged.

Referring to fig. 9, in the embodiment of the present utility model, the inclination angle of the first tooth segment 211 is α ₁, and the inclination angle of the second tooth segment is β ₁. Note that the inclination angle α ₁ of the first tooth segment 211 means that the tooth tip of the first tooth segment 211 is configured as a first inclined surface 2111, the first inclined surface 2111 is inclined in a direction away from the third tooth segment 213 and toward the rotation axis, and an angle between the first inclined surface 2111 and the rotation axis is α ₁. The inclination angle beta ₁ of the second tooth segment means that the tooth tip of the second tooth segment 212 is configured as a second inclined surface 2112, the second inclined surface 2112 being arranged obliquely in a direction away from the third tooth segment 213 and toward the rotational axis, and the angle between the second inclined surface 2112 and the rotational axis being beta ₁.

With continued reference to FIG. 9, the first angled surface 2111 has an angle of inclination α ₁, which satisfies 0.2 ° - (Lc ₂/Lc）*0.6°≤α₁≤0.8°-（Lc₂/Lc) by 0.6. Wherein (Lc ₂/Lc) 0.6 ° is less than or equal to 0.2 °, and (Lc ₂/Lc) 0.6 ° is less than or equal to 0.8 °. When the Lc ₂/Lc ratio is determined, the range of values for α ₁ can be determined as well. For example, lc ₂/Lc=1/6,α₁ has a value in the range of 0.1 DEG≤alpha ₁≤0.7°. Referring to fig. 16, the abscissa in fig. 16 represents the range of values of α ₁, and the ordinate represents the magnitude of the overall vibration of the harmonic reducer 1000. Along with the gradual increase of the value of alpha ₁, the vibration of the whole machine is increased and then reduced. When α ₁ is smaller than 0.2 ° - (Lc ₂/Lc) 0.6 °, that is, the inclination angle of the first inclined surface 2111 is too small, it is difficult to reduce interference between the internal teeth portion 110 and the external teeth portion 210, and vibration of the whole machine increases. When α ₁ is greater than 0.8 ° - (Lc ₂/Lc) ×0.6 °, the effective area when the first tooth segment 211 and the internal tooth portion 110 are meshed is easily reduced, resulting in poor meshing stability and increased vibration of the whole machine. Therefore, the size of α ₁ is reasonably designed, so that interference between the internal tooth portion 110 and the external tooth portion 210 can be effectively reduced, vibration of the whole machine is reduced, the service life of the flexspline 200 is prolonged, and meanwhile, the external tooth portion 210 can be ensured to have proper strength, and reliability is high.

With continued reference to FIG. 9, the second ramp 2112 has an inclination angle β ₁, which satisfies 0.3 ° - (Lc ₁/Lc）*0.6°≤β₁≤0.9°-（Lc₁/Lc) by 0.6. Wherein 0.3 ° - (Lc ₁/Lc) 0.6 ° is less than or equal to 0.3 °, (Lc ₁/Lc) 0.6 ° is less than or equal to 0.9 °. When the Lc ₁/Lc ratio is determined, the range of values for β ₁ can be determined as well. For example, lc ₁/Lc=1/6,β₁ has a value in the range of 0.2 DEG≤β ₁≤0.8°. Referring to fig. 17, the abscissa in fig. 17 represents the range of values of β ₁, and the ordinate represents the magnitude of the overall vibration of the harmonic reducer 1000. Along with the gradual increase of the value of beta ₁, the vibration of the whole machine is increased and then reduced. When β ₁ is smaller than 0.3 ° - (Lc ₁/Lc) ×0.6 °, interference between the internal teeth portion 110 and the external teeth portion 210 is difficult to be reduced, and vibration of the whole machine increases. When β ₁ is greater than 0.9 ° - (Lc ₁/Lc) ×0.6 °, the effective area when the second tooth segment 212 and the internal tooth portion 110 are meshed is easily reduced, resulting in poor meshing stability and increased vibration of the whole machine. Therefore, the size of beta ₁ is reasonably designed, the vibration of the whole machine is reduced, the interference between the internal tooth part 110 and the external tooth part 210 can be effectively reduced, the service life of the flexible gear 200 is prolonged, the external tooth part 210 can be ensured to have proper strength, and the reliability is high.

It should be noted that, since the internal tooth portion 110 includes the first thin-walled segment 111 and the second thin-walled segment 112, that is, the first thin-walled segment 111 and the second thin-walled segment 112 can be elastically deformed to some extent, thereby reducing interference between the internal tooth portion 110 and the external tooth portion 210. Accordingly, the shaping angle for the first tooth segment 211 and the second tooth segment 212 may be reduced or not shaped appropriately to ensure the overall strength of the external tooth portion 210.

With continued reference to fig. 9, in the embodiment of the present utility model, in order to further reduce interference between the external tooth part 210 and the internal tooth part 110, a third inclined surface 2121 is provided between two adjacent first tooth segments 211, and the third inclined surface 2121 is disposed obliquely in a direction away from the third tooth segment 213 and toward the rotation axis. The inclination angle of the third inclined surface 2121 may be the same as or different from the inclination angle of the first inclined surface 2111. The third inclined surface 2121 has an inclination angle α ₂, which satisfies 0.2 ° - (Lc ₂/Lc）*0.6°≤α₂≤0.8°-（Lc₂/Lc) by 0.6 °. When α ₂ is smaller than 0.2 ° - (Lc ₂/Lc) 0.6 °, that is, the inclination angle of the third inclined surface 2121 is too small, it is difficult to reduce interference between the internal teeth portion 110 and the external teeth portion 210. When α ₂ is greater than 0.8 ° - (Lc ₂/Lc) 0.6 °, the strength of the external tooth portion 210 is easily reduced, and tearing is easily generated between adjacent teeth.

A fourth inclined surface 2122 is provided between two adjacent second tooth segments 212, the fourth inclined surface 2122 is inclined in a direction away from the third tooth segment 213 and toward the rotation axis, and the inclination angle of the fourth inclined surface 2122 and the inclination angle of the second inclined surface 2112 may be the same or different. The fourth ramp 2122 has an inclination angle β ₂, satisfying 0.3 ° - (Lc ₁/Lc）*0.6°≤β₂≤0.9°-（Lc₁/Lc) x 0.6 °. When β ₂ is smaller than 0.3 ° - (Lc ₁/Lc) ×0.6 °, it is difficult to reduce interference between the internal teeth portion 110 and the external teeth portion 210. When β ₂ is greater than 0.4 °, the strength of the external tooth portion 210 is easily reduced, and tearing is easily generated between adjacent teeth. Therefore, interference between the tooth top of the inner tooth part 110 and the tooth root of the outer tooth part 210 can be effectively reduced or avoided, friction and abrasion of the tooth surface can be reduced, and the service life of the flexible gear 200 can be prolonged.

TABLE 3 comparison of tooth surface contact areas for different versions

For example, referring to table 3 above, scheme 1 is a scheme in the related art, lc=0.42×lf, lf ₁ =0.36×lf, and the tooth height of the external tooth portion 210 is kept unchanged, i.e. no tooth modification is adopted, scheme 2 is lc=0.55×lf, lf ₁ =0.5×lf, and the tooth height of the external tooth portion 210 is kept unchanged, i.e. no tooth modification is adopted, scheme 3 is lc=0.55×lf, lf ₁ =0.5×lf, and the first tooth segment 211 and the second tooth segment 212 of the external tooth portion 210 are adopted. As can be seen from table 1, when lc=0.55×lf and lf ₁ =0.5×lf are designed, the tooth contact area of the flexspline 200 can be increased by 19.2%, i.e. the tooth width of the flexspline 200 is increased, and the modification is further added, which is 38.5% compared to the increase of the modification 1. While the larger the tooth surface contact area, the smaller the contact stress, and the larger the bearing capacity of the harmonic reducer 1000.

The inner holes of the flexible gears 200 with the same specification have the same diameter and basically the same external dimension. When the reduction ratios of the harmonic speed reducer 1000 are different, the number of teeth and the modulus of the flexspline 200 are generally different, so that the stress applied to the flexspline 200 when deformed is also different. In order to reduce the stress applied to the flexible gear 200 during deformation, and simplify the design of the flexible gear 200 with the same specification but different reduction ratios, referring to fig. 1 and 6, in the embodiment of the present utility model, the wall thickness of the tooth root of the flexible gear 200 is Tf, where the wall thickness Tf of the tooth root refers to the distance between the tooth root of the external tooth portion 210 and the wall of the inner hole of the flexible gear 200 along the radial direction of the flexible gear 200. The inner hole diameter of the flexible gear 200 is Df, the reduction ratio of the harmonic speed reducer 1000 is R, and the requirements that Tf/Df is smaller than or equal to 0.0043ln (R) -0.0061 and smaller than or equal to 0.005ln (R) -0.0036 are met, wherein the reduction ratio R can be obtained through parameters marked by a nameplate on the harmonic speed reducer 10001000.

Referring to fig. 14, the abscissa of the graph in fig. 14 represents the value of Tf/Df, and the ordinate represents the root stress of the flexspline 200. As can be seen from fig. 14, as Tf/Df increases gradually, the root stress to which the flexspline 200 is subjected decreases and increases, and there is a minimum value for the root stress. Therefore, for the flexspline 200 with the same specification but different reduction ratios, the influence of the reduction ratio R is eliminated by using the natural logarithmic function LnN, and the stress to which the flexspline 200 is subjected can be effectively reduced only by ensuring that the values of Tf/Df are limited to the ranges of 0.0043ln (R) -0.0061 and 0.005ln (R) -0.0036, and meanwhile, the design of the flexspline 200 can be simplified, the production efficiency can be improved, and the method is suitable for improving the stress distribution of the harmonic reducers 1000 with different reduction ratios R, and reducing the stress to which the flexspline 200 is subjected during deformation. Meanwhile, compared with the flexspline in the related art, the wall thickness Tf of the tooth root of the flexspline 200 of the present embodiment is increased, so that the bearing capacity and torsional rigidity of the harmonic reducer 1000 can be effectively improved.

Referring to fig. 2, in the embodiment of the present utility model, the effective width of the flexspline 200 is Lf along the axial direction of the wave generator 300, and the effective width of the flexspline 200 refers to the minimum distance between the end surface of the end of the cylindrical portion 220 facing away from the flange portion 240 and the flange portion 240. The width of the internal tooth portion 110 is Lc, and the width of the internal tooth portion 110 refers to the maximum length of the internal tooth portion 110 in the axial direction, for example, the distance between the two furthest end faces of the rigid wheel 100 in the axial direction. The relationship of Lf and Lc satisfies: lf is greater than or equal to 0.45 and Lc is greater than or equal to 0.65. The values of Lc may be 0.45×lf, 0.5×lf, 0.51×lf, 0.53×lf, 0.55×lf, 0.58×lf, and 0.65×lf. When Lc is less than 0.45×lf, that is, the maximum length of the internal tooth portion 110 is short, the tooth surface contact area of the internal tooth portion 110 and the external tooth portion 210 is reduced, the contact stress is increased, and the bearing capacity of the harmonic speed reducer 1000 is reduced. When Lc is greater than 0.65×lf, that is, the maximum length of the internal tooth portion 110 is greater, the occupied space is excessive, and the strength margin is too large, which is not beneficial to the miniaturized design of the harmonic reducer 1000. Therefore, the size between the maximum lengths Lc and Lf of the internal tooth portion 110 is reasonably designed, so that the tooth surface contact area of the internal tooth portion 110 and the external tooth portion 210 can be effectively increased, the contact stress is reduced, the bearing capacity of the harmonic speed reducer 1000 is improved, and meanwhile, the miniaturized design of the harmonic speed reducer 1000 is facilitated.

Referring to fig. 7, 10 and 11, in the embodiment of the present utility model, the outer bearing ring 410 includes a second mounting portion 411 and a boss portion 412 connected to the inside of the second mounting portion 411, and both ends of the boss portion 412 in the axial direction are provided with a first outer raceway 413 and a second outer raceway 414, respectively, which are apart from each other. The protruding portion 412 can improve the structural strength of the first outer raceway 413 and the second outer raceway 414, effectively reduce deformation of the first outer raceway 413 and the second outer raceway 414, and simultaneously limit the first rolling element 431 and the second rolling element 441, so as to avoid contact between the first rolling element 431 and the second rolling element 441. The inner bearing ring 420 is provided with a groove 422 disposed opposite to the boss 412, and both ends of the groove 422 in the axial direction are a first inner raceway 423 and a second inner raceway 424, respectively. The first inner raceway 423 and the first outer raceway 413 are disposed opposite one another and form a first groove body 430, and the second inner raceway 424 and the second outer raceway 414 are disposed opposite one another and form a second groove body 440. By adopting the scheme, the first rolling bodies 431 and the second rolling bodies 441 are conveniently installed, the assembly efficiency is improved, the first rolling bodies 431 and the second rolling bodies 441 can smoothly rotate, and the running stability of the support bearing 400 is improved.

Referring to fig. 7, in the embodiment of the present utility model, a gap is formed between the boss 412 and the bottom wall of the recess 422, and the first groove 430 and the second groove 440 are communicated through the gap. It can be appreciated that by providing the first groove 430 and the second groove 440 to communicate through a gap, lubricating oil is facilitated to flow in the first groove 430 and the second groove 440, so as to lubricate the first rolling element 431 and the second rolling element 441, and improve the smoothness and the service life of the rolling elements 431 and 441.

With continued reference to FIG. 7, in an embodiment of the utility model, the inner bearing ring 420 includes first 425 and second 426 rings that are connected, with the first 425 and second 426 rings being arranged in a left-to-right direction, with the connection being by fasteners. Wherein a step is disposed on a side of the first ring 425 facing the second ring 426, and the second ring 426 is positioned and connected to the step. The steps serve as a location to facilitate connection of the first ring 425 and the second ring 426. The first inner raceway 423 is disposed outside the first ring body 425 and is close to the second ring body 426, the second inner raceway 424 is disposed outside the second ring body 426 and is far away from the first ring body 425, and the second ring body 426 is connected with the rigid gear 100. By designing the inner bearing ring 420 to be connected with the first ring body 425 and the second ring body 426, the installation of the first rolling bodies 431 and the second rolling bodies 441 is facilitated, and the assembly difficulty is reduced.

With continued reference to fig. 7, in an embodiment of the present utility model, the outer side of the first thin-walled segment 111 abuts the inner side of the second ring body 426. Along the axial direction of the wave generator 300, one end of the second ring body 426 away from the first ring body 425 is abutted with one end of the first mounting part 120 facing the first thin-wall section 111, so that the second ring body 426 can be positioned, the second ring body 426 is convenient to assemble, and the assembly efficiency is improved.

An industrial robot according to an embodiment of the present utility model includes a motor and the harmonic reducer 1000 of the above embodiment. It is understood that the motor may be a servo motor, and the servo motor is in driving connection with the harmonic reducer 1000 for performing deceleration control on the joints of the industrial robot. The industrial robot may be a transfer robot, welding robot, assembly robot, machining robot, painting robot, cleaning robot, collaborative robot, or the like.

The industrial robot according to the embodiment of the present utility model adopts the harmonic reducer 1000 of the above embodiment, and the wave generator 300 is disposed inside the flexspline 200, so that the external tooth portion 210 of the flexspline 200 and the internal tooth portion 110 of the rigid spline 100 are partially meshed, and when the wave generator 300 rotates, the flexspline 200 and the rigid spline 100 can be driven to rotate relatively. A first groove 430 and a second groove 440 are provided between the inner bearing ring 420 and the outer bearing ring 410 of the support bearing 400, the first groove 430 is used for mounting the first rolling element 431, the second groove 440 is used for mounting the second rolling element 441, and the first groove 430 and the second groove 440 are arranged at intervals along the axial direction of the wave generator 300. Through setting up two sets of rolling bodies, can effectively promote the bearing capacity of harmonic speed reducer 1000, when keeping complete machine compact structure, promote the assembly efficiency between bearing device and rigid gear 100, the flexspline 200. Since the first mounting portion 120 of the rigid gear 100 is connected to the middle portion of the internal gear 110 and the first thin-walled segment 111 and the second thin-walled segment 112 of the internal gear 110 are connected to both ends of the first mounting portion 120, respectively, the first thin-walled segment 111 and the second thin-walled segment 112 can be elastically deformed to some extent. The two ends of the external tooth part 210 of the flexible gear 200 along the axial direction are respectively matched with the first thin-wall section 111 and the second thin-wall section 112, when the external tooth part 210 is stressed too much, interference with the first thin-wall section 111 and the second thin-wall section 112 can be reduced under the elastic deformation of the first thin-wall section 111 and the second thin-wall section 112, so that vibration and noise of the harmonic reducer 1000 are reduced, frictional wear of the flexible gear 200 is reduced, and the service life of the flexible gear 200 is prolonged.

The industrial robot according to the embodiment of the present utility model adopts all the technical solutions of the harmonic reducer 1000 of the above embodiment, so that the industrial robot at least has all the beneficial effects brought by the technical solutions of the above embodiment, and will not be described herein.

The embodiments of the present utility model have been described in detail with reference to the accompanying drawings, but the present utility model is not limited to the above embodiments, and various changes can be made within the knowledge of one of ordinary skill in the art without departing from the spirit of the present utility model.

Claims

1. The harmonic speed reducer, its characterized in that includes:

The rigid wheel comprises a first mounting part and an inner tooth part connected to the inner side of the first mounting part;

The flexible gear is arranged in the rigid gear and comprises an external tooth part;

a wave generator provided inside the flexspline and adapted to mesh the external tooth portion with the internal tooth portion;

A support bearing configured to enable the rigid gear and the flexible gear to rotate relatively, wherein the support bearing comprises an outer bearing ring and an inner bearing ring arranged in the outer bearing ring, a first groove body used for installing a first rolling body and a second groove body used for installing a second rolling body are arranged between the inner bearing ring and the outer bearing ring, and the first groove body and the second groove body are arranged at intervals along the axial direction of the wave generator;

The first mounting portion is connected with the inner bearing ring, the first mounting portion is connected to the middle of the inner tooth portion along the axial direction of the wave generator, the inner tooth portion comprises a first thin-wall section and a second thin-wall section, the first thin-wall section is located at one end of the first mounting portion towards the inner bearing ring, the outer side of the first thin-wall section is abutted to the inner side of the inner bearing ring, and the second thin-wall section is located at one end of the first mounting portion away from the inner bearing ring.

2. The harmonic reducer of claim 1, wherein the wave generator further comprises a flexible bearing connected to the inner bore of the flexible gear, the inner tooth portion has a width Lc, and a distance between a center line of the first mounting portion in the axial direction and a plane in which centers of all rolling elements of the flexible bearing are located is Lbc, so that Lbc is equal to or less than 0.1 x Lc.

3. The harmonic reducer of claim 1, wherein the first thin-walled segment has a width Lc ₁ and the second thin-walled segment has a width Lc ₂ in the axial direction, and the internal tooth portion has a width Lc satisfying 0.6Xlc≤Lc ₁+Lc₂≤0.9Xlc.

4. The harmonic reducer of claim 1 or 2, wherein the maximum wall thickness of the first thin-wall section is Tc ₁, the maximum wall thickness of the second thin-wall section is Tc ₂, and the inner hole diameter of the flexspline is Df, and the Df is more than or equal to 0.015 and less than or equal to Tc ₁≤0.05*Df,0.015*Df≤Tc₂ and less than or equal to 0.05.

5. The harmonic reducer of claim 1 or 2, wherein the junction between the first thin-wall section and the first mounting portion is configured as a first curve, the first curve is composed of at least two circular arc sections, the first curve and the outer side of the first thin-wall section are connected to a ₁ point, the first curve and the first mounting portion are connected to an e ₁ point, and a distance from the a ₁ point to the e ₁ point along the axial direction is Lwa ₁, so that 0.1 x lc ₁≤Lwa₁≤0.3*Lc₁ is satisfied.

6. The harmonic reducer of claim 5, wherein the first curve has a point b ₁, a point c ₁ and a point d ₁, the distance from the point a ₁ to the point b ₁ is Lwb ₁,b₁ to the point c ₁, the distance from the point Lwc ₁,c₁ to the point d ₁ is Lwd ₁,Lwb₁=Lwc₁=Lwd₁=Lwa₁/4;

The maximum wall thickness of the first thin-wall section is Tc ₁, and the distances from the point b ₁, the point c ₁, the point d ₁, the point e ₁ and the point a ₁ along the radial direction of the rigid wheel are Lrb₁、Lrc₁、Lrd₁、Lre₁,Lrb₁＜Lrc₁＜Lrd₁＜Lre₁, respectively ：0.1*Tc₁≤Lre₁≤0.4*Tc₁,Lrb₁+Lrc₁+Lrd₁≤Lre₁/2.

7. The harmonic reducer of claim 1 or 2, wherein the junction between the second thin-wall section and the first mounting portion is configured as a second curve, the second curve is composed of at least two circular arc sections, the second curve and the outer side of the second thin-wall section are connected at a ₂ point, the second curve and the first mounting portion are connected at an e ₂ point, and a distance from the a ₂ point to the e ₂ point along the axial direction is Lwa ₂, so that 0.1 x lc ₁≤Lwa₂≤0.3*Lc₁ is satisfied.

8. The harmonic reducer of claim 7, wherein the second curve has a point b ₂, a point c ₂ and a point d ₂, the distance from the point a ₂ to the point b ₂ is Lwb ₂,b₂ to the point c ₂, the distance from the point Lwc ₂,c₂ to the point d ₂ is Lwd ₂, Lwb₂=Lwc₂=Lwd₂=Lwa₂/4;

The maximum wall thickness of the second thin-wall section is Tc ₂, and the distances from the point b ₂, the point c ₂, the point d ₂, the point e ₂ and the point a ₂ along the radial direction of the rigid wheel are Lrb₂、Lrc₂、Lrd₂、Lre₂,Lrb₂＜Lrc₂＜Lrd₂＜Lre₂, respectively ：0.1*Tc₂≤Lre₂≤0.4*Tc₂,Lrb₂+Lrc₂+Lrd₂≤Lre₂/2.

9. The harmonic reducer of claim 1, wherein the flexspline further comprises a cylindrical portion, a diaphragm portion and a flange portion, the external tooth portion is connected to the outside of one end of the cylindrical portion, the diaphragm portion is connected to the other end of the cylindrical portion and extends in the radial direction of the cylindrical portion, the flange portion is connected to one end of the diaphragm portion away from the cylindrical portion, and the flange portion is fixedly connected with the external bearing ring.

10. The harmonic reducer of claim 9, wherein the external tooth section includes a first tooth section distant from one end of the flange section and a second tooth section close to one end of the flange section in the axial direction, a diameter of a tip circle of the first tooth section gradually decreases in a direction distant from the flange section, and a diameter of a tip circle of the second tooth section gradually decreases in a direction toward the flange section.

11. The harmonic reducer of claim 10, wherein the external tooth section further comprises a third tooth section between the first tooth section and the second tooth section, the diameter of the tip circle of the third tooth section being constant.

12. The harmonic reducer of claim 11, wherein the effective width of the flexspline is Lf, the width of the external teeth is Lf ₁, the width of the first tooth segment is Lf ₂, the width of the second tooth segment is Lf ₄, and the width of the third tooth segment is Lf ₃, in the axial direction, satisfying:

0.4*Lf≤Lf₁≤0.6*Lf;

0.2*Lf₁≤Lf₂≤0.35*Lf₁;

0.35*Lf₁≤Lf₃≤0.45*Lf₁;

0.25*Lf₁≤Lf₄≤0.4*Lf₁。

13. The harmonic reducer of claim 10, wherein the first thin-walled segment has a width Lc ₁ and the second thin-walled segment has a width Lc ₂ in the axial direction, the internal tooth portion has a width Lc, the first tooth segment has an inclination angle α ₁, and the second tooth segment has an inclination angle β ₁, satisfying the following conditions:

0.2°-(Lc₂/Lc）*0.6°≤α₁≤0.8°-（Lc₂/Lc)*0.6°;

0.3°-(Lc₁/Lc）*0.6°≤β₁≤0.9°-（Lc₁/Lc)*0.6°。

14. the harmonic reducer of claim 1 or 2, wherein the wall thickness of the tooth root of the flexible gear is Tf, the diameter of the inner hole of the flexible gear is Df, and the reduction ratio of the harmonic reducer is R, and the reduction ratio is 0.0043ln (R) -0.0061 is less than or equal to Tf/Df is less than or equal to 0.005ln (R) -0.0036.

15. The harmonic reducer of claim 1 or 2, wherein the effective width of the flexspline is Lf and the width of the internal tooth portion is Lc in the axial direction, and the ratio of Lf to Lf is 0.45×lc to 0.65×lf.

16. The harmonic reducer of claim 1, wherein the outer bearing ring comprises a second mounting part and a protruding part connected to the inner side of the second mounting part, and the protruding part is respectively provided with a first outer raceway and a second outer raceway which are opposite to each other along the two ends of the axial direction;

the outer side of the inner bearing ring is provided with a groove which is arranged opposite to the protruding part, and the two ends of the groove along the axial direction are respectively provided with a first inner raceway and a second inner raceway;

The first inner roller path and the first outer roller path are arranged oppositely to form the first groove body, and the second inner roller path and the second outer roller path are arranged oppositely to form the second groove body.

17. The harmonic reducer of claim 16, wherein the inner bearing ring comprises a first ring body and a second ring body which are connected, the first inner raceway is arranged on the outer side of the first ring body and is close to the second ring body, the second inner raceway is arranged on the outer side of the second ring body and is far away from the first ring body, and the second ring body is connected with the rigid gear.

18. The harmonic reducer of claim 17, wherein the outer side of the first thin-walled segment abuts against the inner side of the second ring body, a protruding portion protrudes toward one end away from the first ring body, and the inner side of the protruding portion abuts against the outer side of the first mounting portion.

19. An industrial robot comprising the harmonic reducer according to any one of claims 1 to 18.