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, wave generator and support bearing, wave generator is located in flexible gear, and the support bearing is equipped with first groove and second groove between the inner bearing ring and outer bearing ring, the first groove body is used for installing the first rolling body, and the second groove body is used for installing the second rolling body. The rigid gear comprises a first installation part and an inner tooth part which are connected, the first installation part is located at the end, away from the inner bearing ring, of the inner tooth part, and when the installation hole is formed in the inner bearing ring, the influence degree on a roller path is small. The inner tooth part protrudes out of the first installation part, the inner tooth part is of a thin-wall design, elastic deformation can be generated to a certain degree, interference between the inner tooth part and the outer tooth part is reduced through the elastic deformation of the inner tooth part under the condition that the meshing depth of the inner tooth part and the outer tooth part is not reduced, and therefore the bearing capacity of the harmonic speed reducer is improved, and vibration and noise are reduced.

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 related technologies, a harmonic reducer includes a wave generator, a flexspline, and a rigid pulley. The wave generator is embedded in the inner hole of the flexspline, and the outer teeth of the flexspline mesh with the inner teeth of the rigid pulley. Rotation of the wave generator causes different parts of the outer and inner teeth to mesh, resulting in relative rotation between the rigid pulley and the flexspline, achieving power output. The rigid pulley has high overall rigidity, and when the flexspline bears high pressure, it is prone to interference with the rigid pulley, resulting in increased vibration and noise in the harmonic reducer. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a harmonic reducer that can reduce the difficulty of machining the support bearing and reduce the interference between the rigid wheel and the flexible wheel, thereby reducing vibration and noise.

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

[0005] According to the first embodiment of the present invention, the harmonic reducer includes: a rigid wheel, including a first mounting portion and an inner tooth portion connected to the inner side of the first mounting portion; a flexible wheel, arranged inside the rigid wheel, the flexible wheel including an outer tooth portion; a wave generator, arranged inside the flexible wheel, and used to make the outer tooth portion and the inner tooth portion partially mesh; a support bearing, configured to enable the rigid wheel and the flexible wheel to rotate relative to each other, the support bearing including an outer bearing ring and an inner bearing ring arranged inside the outer bearing ring, and a space between the inner bearing ring and the outer bearing ring for providing A first groove body for mounting a first rolling body and a second groove body for mounting a second rolling body, the first groove body and the second groove body are arranged at intervals along the axial direction of the wave generator; wherein, the first mounting portion is connected to the inner bearing ring, and along the axial direction of the wave generator, the first mounting portion is connected to the end of the inner tooth portion away from the inner bearing ring, the inner tooth portion includes a thin-walled section protruding from the first mounting portion, the width of the thin-walled section is Lc1, and the width of the inner tooth portion is Lc, satisfying: 0.6*Lc≤Lc1≤0.9*Lc.

[0006] The harmonic reducer according to the embodiment of the utility model has at least the following beneficial effects:

[0007] By positioning the wave generator within the flexspline and partially meshing the outer teeth of the flexspline with the inner teeth of the rigid pulley, rotation of the wave generator drives the flexspline and the rigid pulley to rotate relative to each other. A first groove and a second groove are provided between the inner and outer bearing rings of the support bearing. The first groove accommodates a first rolling element, while the second groove accommodates a second rolling element. The first and second grooves are spaced axially along the wave generator. The provision of two sets of rolling elements effectively improves the load-bearing capacity of the harmonic reducer, while maintaining the overall compactness of the unit and enhancing the assembly efficiency between the bearing assembly, the rigid pulley, and the flexspline. Because the rigid pulley includes a first mounting portion and an inner toothed portion connected to each other, with the first mounting portion located at the end of the inner toothed portion facing away from the inner bearing ring, the inner bearing ring can extend to the outer wall of the inner toothed portion, resulting in a longer overall length. The provision of mounting holes in the inner bearing ring minimizes the impact on the raceway, thereby reducing the difficulty of machining the support bearing. At the same time, since the inner tooth portion protrudes from the first mounting portion, the inner tooth portion is designed with a thin wall and can produce elastic deformation to a certain extent. Therefore, without reducing the meshing depth of the inner tooth portion and the outer tooth portion, the elastic deformation of the inner tooth portion is used to reduce the interference with the outer tooth portion, thereby improving the load-bearing capacity of the harmonic reducer and reducing vibration and noise.

[0008] According to some embodiments of the present invention, the maximum wall thickness of the thin-walled section is Tc, and the inner hole diameter of the flexible wheel is Df, which satisfies: 0.015*Df≤Tc≤0.05*Df.

[0009] According to some embodiments of the present invention, the connection between the thin-walled section and the first mounting portion is constructed as a curve, which is composed of at least two circular arc segments. The curve is connected to the outer side of the thin-walled section at point a, and the curve is connected to the first mounting portion at point e. Along the axial direction, the distance from point a to point e is Lwa, satisfying: 0.1*Lc1≤Lwa≤0.3*Lc1.

[0010] According to some embodiments of the present invention, the curve has points b, c and d, the distance from point a to point b is Lwb, the distance from point b to point c is Lwc, the distance from point c to point d is Lwd, and Lwb=Lwc=Lwd=Lwa / 4; along the radial direction of the rigid wheel, the distances from point b, point c, point d, point e to point a are Lrb, Lrc, Lrd, and Lre, respectively, Lrb<Lrc<Lrd<Lre, satisfying: 0.1*Tc≤Lre≤0.4*Tc, Lrb+Lrc+Lrd≤Lre / 2.

[0011] According to some embodiments of the present invention, the flexible wheel also includes a cylinder, a diaphragm and a flange, the external tooth portion is connected to the outer side of one end of the cylinder, the diaphragm is connected to the other end of the cylinder and extends radially along the cylinder, the flange portion is connected to the end of the diaphragm away from the cylinder, and the flange portion is fixedly connected to the outer bearing ring.

[0012] According to some embodiments of the present invention, along the axial direction, the external tooth portion includes a first tooth segment away from one end of the flange portion and a second tooth segment close to one end of the flange portion, the diameter of the tooth top circle of the first tooth segment gradually decreases in the direction away from the flange portion, and the diameter of the tooth top circle of the second tooth segment gradually decreases in the direction toward the flange portion.

[0013] According to some embodiments of the present invention, the external tooth portion further includes a third tooth segment located between the first tooth segment and the second tooth segment, and the diameter of the tooth top circle of the third tooth segment is constant.

[0014] According to some embodiments of the present invention, along the axial direction, the effective width of the flexible spline is Lf, the width of the outer tooth portion is Lf1, the width of the first tooth segment is Lf2, the width of the second tooth segment is Lf4, and the width of the third tooth segment is Lf3, satisfying the following: 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.

[0015] According to some embodiments of the present invention, the inclination angle of the first tooth segment is α1, and the inclination angle of the second tooth segment is β1, satisfying: 0.3°≤α1≤1.0°, 0°≤β1≤0.4°, and β1<α1.

[0016] According to some embodiments of the present invention, the tooth root wall thickness of the flexspline is Tf, the inner hole diameter of the flexspline is Df, and the reduction ratio of the harmonic reducer is R, which satisfies: 0.0043ln(R)-0.0061≤Tf / Df≤0.005ln(R)-0.0036.

[0017] According to some embodiments of the present invention, along the axial direction, the effective width of the flexspline is Lf, which satisfies: 0.45*Lf≤Lc≤0.65*Lf.

[0018] According to some embodiments of the present invention, the outer bearing ring includes a second mounting portion and a raised portion connected to the inner side of the second mounting portion, and the raised portion is respectively provided with a first outer raceway and a second outer raceway at both ends along the axial direction, which are opposite to each other; the outer side of the inner bearing ring is provided with a groove arranged opposite to the raised portion, and the groove is respectively provided with a first inner raceway and a second inner raceway at both ends along the axial direction; the first inner raceway and the first outer raceway are arranged opposite to each other and form the first groove body, and the second inner raceway and the second outer raceway are arranged opposite to each other and form the second groove body.

[0019] According to some embodiments of the present invention, there is a gap between the protrusion and the bottom wall of the groove, and the first groove body and the second groove body are connected through the gap.

[0020] According to some embodiments of the present invention, the inner bearing ring includes a first ring body and a second ring body connected to each other, the first inner raceway is arranged on the outside of the first ring body and close to the second ring body, the second inner raceway is arranged on the outside of the second ring body and away from the first ring body, and the second ring body is connected to the rigid wheel.

[0021] According to some embodiments of the present invention, the outer side of the thin-walled section abuts against the inner side of the second ring body; along the axial direction, the end of the second ring body away from the first ring body abuts against the end of the first mounting portion facing the thin-walled section.

[0022] The industrial robot according to the embodiment of the second aspect of the present utility model includes the harmonic reducer described in the above embodiment.

[0023] The industrial robot according to the embodiment of the present utility model has at least the following beneficial effects:

[0024] A harmonic reducer employing the first embodiment of the present invention comprises a wave generator positioned within the flexspline, with the outer teeth of the flexspline partially meshing with the inner teeth of the rigid wheel. Rotation of the wave generator drives the flexspline and the rigid wheel to rotate relative to each other. A first groove and a second groove are provided between the inner and outer bearing rings of the support bearing. The first groove accommodates a first rolling element, while the second groove accommodates a second rolling element. The first and second grooves are spaced axially from each other along the wave generator. The provision of two sets of rolling elements effectively improves the load-bearing capacity of the harmonic reducer, while maintaining the overall compactness of the structure and enhancing the assembly efficiency between the bearing assembly, the rigid wheel, and the flexspline. Because the rigid wheel includes a first mounting portion and an internal toothed portion connected thereto, with the first mounting portion located at the end of the internal toothed portion facing away from the inner bearing ring, the inner bearing ring can extend to the outer wall of the internal toothed portion, resulting in a longer overall length. The provision of mounting holes in the inner bearing ring minimizes the impact on the raceway, thereby reducing the difficulty of machining the support bearing. At the same time, since the inner tooth portion protrudes from the first mounting portion, the inner tooth portion is designed with a thin wall and can produce elastic deformation to a certain extent. Therefore, without reducing the meshing depth of the inner tooth portion and the outer tooth portion, the elastic deformation of the inner tooth portion is used to reduce the interference with the outer tooth portion, thereby improving the load-bearing capacity of the harmonic reducer and reducing vibration and noise.

[0025] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0027] Figure 1 This is a schematic cross-sectional view of the structure of a harmonic reducer according to an embodiment of the present invention;

[0028] Figure 2 This is a partial structural cross-sectional diagram of a flexible spline and a rigid spline according to an embodiment of the present invention;

[0029] Figure 3 This is a partial structural diagram of a rigid wheel according to an embodiment of the present utility model;

[0030] Figure 4 for Figure 3 Enlarged view of point B in the middle;

[0031] Figure 5 This is a partial structural diagram of a flexible pulley according to an embodiment of the present invention;

[0032] Figure 6 for Figure 1 Enlarged view of point A in the middle;

[0033] Figure 7 This is a schematic cross-sectional view of a portion of the outer tooth portion of an embodiment of the present invention;

[0034] Figure 8 This is a schematic cross-sectional view of a portion of the outer tooth portion of an embodiment of the present invention;

[0035] Figure 9 This is a schematic structural diagram of an inner bearing ring according to an embodiment of the present invention;

[0036] Figure 10 This is a cross-sectional view of an outer bearing ring according to an embodiment of the present invention;

[0037] Figure 11 This is a relationship diagram of the ratio L3 / Lc, the weight of the entire machine, and the vibration acceleration of an embodiment of the present utility model;

[0038] Figure 12 This is a relationship diagram of the ratio L1 / Lf, the allowable torque of the support bearing, and the weight of the entire machine in one embodiment of the present utility model;

[0039] Figure 13 Graph showing the relationship between the ratio Tf / Df and the flexspline tooth root stress in one embodiment of the present invention.

[0040] Figure Number:

[0041] Harmonic reducer 1000;

[0042] Ring 100; inner tooth portion 110; thin-walled section 111; first mounting portion 120; curve 130;

[0043] Flexspline 200 ; external tooth portion 210 ; first tooth segment 211 ; first inclined surface 2111 ; second inclined surface 2112 ; second tooth segment 212 ; third inclined surface 2121 ; fourth inclined surface 2122 ; third tooth segment 213 ; cylinder portion 220 ; diaphragm portion 230 ; flange portion 240 ;

[0044] Wave generator 300; cam 310; flexible bearing 320;

[0045] Support bearing 400; outer bearing ring 410; second mounting portion 411; protrusion 412; first outer raceway 413; second outer raceway 414; inner bearing ring 420; protrusion 421; groove 422; first inner raceway 423; second inner raceway 424; first ring body 425; second ring body 426; mounting hole 427; first groove body 430; first rolling element 431; second groove body 440; second rolling element 441;

[0046] Oil seal 500. DETAILED DESCRIPTION

[0047] The following describes embodiments of the present invention in detail. 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 intended only to explain the present invention and are not to be construed as limiting the present invention.

[0048] In the description of the present invention, it should be understood that descriptions involving orientation, such as the orientation or positional relationship indicated by up, down, etc., are based on the orientation or positional relationship shown in the accompanying 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.

[0049] In the description of this utility model, "a plurality" means more than two. The use of "first" or "second" is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or implicitly indicating the order of the technical features indicated.

[0050] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting 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.

[0051] Reference Figure 1 and Figure 2 As shown, a harmonic reducer 1000 according to an embodiment of the present invention includes a flexspline 200, a rigid wheel 100, and a wave generator 300. The flexspline 200 is coaxially mounted within the rigid wheel 100, and the wave generator 300 is coaxially mounted within the inner bore of the flexspline 200. The flexspline 200 includes a barrel 220, a diaphragm 230, and a flange 240. The barrel 220 is located at the end of the flexspline 200 that is close to the rigid wheel 100. The diaphragm 230 is connected to the end of the barrel 220 that is away from the rigid wheel 100 and extends radially from the barrel 220. The flange 240 is connected to the outer periphery of the diaphragm 230. The barrel 220 of the flexspline 200 is provided with a flexible outer tooth portion 210. The outer tooth portion 210 is a structure that protrudes radially outward from the barrel 220. The outer tooth portion 210 is not formed within the inner bore of the flexspline 200, but rather on the outer wall of the barrel 220. The rigid wheel 100 is provided with an inner tooth portion 110 , and the outer tooth portion 210 cooperates with the inner tooth portion 110 , and a meshing gap is formed between the outer tooth portion 210 and the inner tooth portion 110 .

[0052] In this embodiment of the present invention, the wave generator 300 is interference-fitted into the inner bore of the flexspline 200. Rotation of the wave generator 300 causes the outer teeth 210 to partially engage with the inner teeth 110. Partial engagement refers to the circumferential deformation of the outer teeth 210 of the flexspline 200, which results in the partial engagement of the deformed portions of the outer teeth 210 with corresponding portions of the inner teeth 110. Specifically, the meshing positions of the inner and outer teeth 110 and 210 cyclically move along the circumferential direction. When the wave generator 300 is installed in the inner bore of the flexspline 200, it forces the flexspline 200 to elastically deform and assume an elliptical shape. During operation of harmonic reducer 1000, wave generator 300 rotates at high speed, causing flexspline 200 to repeatedly deform, causing the outer teeth 210 of flexspline 200 to mesh with the inner teeth 110 of rigid wheel 100. The meshing position of the outer teeth 210 and the inner teeth 110 moves circumferentially along the rotation axis of wave generator 300, thereby achieving relative deceleration motion between flexspline 200 and rigid wheel 100. Wave generator 300 includes a flexible bearing 320 and a cam 310. The flexible bearing 320 is mounted on the outside of the cam 310, while the cam 310 has a mounting position for connecting to a drive device such as a motor.

[0053] Reference Figure 1 As shown, a harmonic reducer 1000 according to an embodiment of the present invention further includes a support bearing 400, which is configured to enable relative rotation between the rigid wheel 100 and the flexible wheel 200. 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 within the outer bearing ring 410. 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, the first groove 430 is located on the side away from the rigid wheel 100, and the second groove 440 is located on the side close to the rigid wheel 100 and spaced apart from the first groove 430. That is, the first groove 430 is located on the left side of the harmonic reducer 1000, and the second groove 440 is located on the right side of the harmonic reducer 1000. Multiple first rolling elements 431 are provided and mounted in the first groove 430; multiple second rolling elements 441 are provided and mounted in the second groove 440. The inner bearing ring 420 is fixedly connected to the rigid spline 100, while the outer bearing ring 410 is fixedly connected to the flange 240 of the flexspline 200. This connection can be achieved through fasteners (such as screws, bolts, pins, etc.), or by clamping, bonding, or other methods. Therefore, the coordination of the first rolling elements 431, the second rolling elements 441, the inner bearing ring 420, and the outer bearing ring 410 facilitates relative rotation between the flexspline 200 and the rigid spline 100.

[0054] By employing two sets of rolling elements, consisting of a plurality of first rolling elements 431 and a plurality of second rolling elements 441, the bearing assembly's load-bearing capacity can be improved compared to single-row crossed roller bearings in related art. Furthermore, the structure of the inner bearing ring 420 and the outer bearing ring 410 facilitates assembly of the harmonic reducer 1000 and makes it easier to adapt to different loads. It is understood that the first rolling elements 431 can be spheres, cylinders, cones, or other cylindrical objects; and the second rolling elements 441 can be spheres, cylinders, cones, or other cylindrical objects, without further limitation. Furthermore, in this embodiment, the first and second rolling elements 431, 441 can be made of metal materials such as steel.

[0055] It should be noted that the inner hole of the flexspline 200 is circular when not installed with the wave generator 300. Once the flexspline 200 and the wave generator 300 are assembled, the outer tooth portion 210 of the flexspline 200 becomes elliptical. Due to the structure of the flexspline 200, the deformation of the outer tooth portion 210 varies along the axial direction at different cross-sections, with the deformation increasing the closer to the opening of the barrel 220. Generally, the meshing state of the middle tooth segment of the outer tooth portion 210 along the axial direction is optimal. The tooth segment near the flange 240 is more likely to interfere with the tooth top of the inner tooth portion 110 of the rigid wheel 100 or have an insufficient clearance, resulting in abnormal friction, wear, and noise. The tooth segment away from the flange 240 is more likely to interfere with the tooth root or middle portion of the inner tooth portion 110 of the rigid wheel 100, similarly resulting in abnormal friction, wear, and noise. Since the rigid wheel and the inner bearing ring 420 are fixedly connected, usually by screws or bolts, it is necessary to set a mounting hole 427 on the inner bearing ring 420, which may cause deformation of the raceway on the inner bearing ring 420, thereby increasing the difficulty of processing the inner bearing ring 420.

[0056] In order to improve the situation that the outer tooth portion 210 easily interferes with the inner tooth portion 110 and the inner bearing ring 420 is difficult to process, refer to Figure 3 and Figure 4 As shown, in an embodiment of the present invention, the rigid wheel 100 includes a first mounting portion 120 and an inner tooth portion 110 connected to the inner side of the first mounting portion 120. The first mounting portion 120 is connected to the inner bearing ring 420. The first mounting portion 120 and the inner bearing ring 420 are connected by fasteners. For example, a mounting hole 427 is provided in the bearing ring 420, and screws, bolts, etc. are inserted through the mounting hole 427 to securely connect the first mounting portion 120 and the inner bearing ring 420. The first mounting portion 120 is connected to the end of the inner tooth portion 110 facing away from the inner bearing ring 420. The inner tooth portion 110 includes a thin-walled section 111 protruding from the first mounting portion 120.

[0057] It is understood that with the above solution, since the rigid wheel 100 includes a connected first mounting portion 120 and an inner tooth portion 110, and the first mounting portion 120 is located at the end of the inner tooth portion 110 facing away from the inner bearing ring 420, the inner bearing ring 420 can extend to the outer wall of the inner tooth portion 110, resulting in a longer overall length of the inner bearing ring 420. Providing the mounting holes 427 on the inner bearing ring 420 minimizes the impact on the raceway, thereby reducing the difficulty of manufacturing the support bearing 400. Furthermore, since the inner tooth portion 110 protrudes from the first mounting portion 120, the inner tooth portion 110 has a thin-walled design, which allows for a certain degree of elastic deformation. Therefore, without reducing the meshing depth between the inner tooth portion 110 and the outer tooth portion 210, the elastic deformation of the inner tooth portion 110 is utilized to reduce interference with the outer tooth portion 210, thereby improving the load-bearing capacity of the harmonic reducer 1000 and reducing vibration and noise.

[0058] Reference Figure 3 and Figure 4 As shown, in the embodiment of the present invention, along the axial direction of the wave generator 300, the maximum width of the thin-walled section 111 is Lc1, and the maximum width of the inner tooth portion 110 is Lc, which satisfies: 0.6*Lc≤Lc1≤0.9*Lc. This formula is equivalent to 0.6≤Lc1 / Lc≤0.9. For example, the value of Lc1 / Lc can be 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, etc. Figure 11 As shown, Figure 11 The horizontal axis in the figure represents the value of Lc1 / Lc, the vertical axis on the left represents the torsional stiffness of the harmonic reducer 1000, and the vertical axis on the right represents the vibration acceleration of the harmonic reducer 1000. Among them, torsional stiffness refers to the slope of the line segment taken on the mechanical hysteresis loop, expressed as the torque change corresponding to the unit torsional angle. The torsional stiffness describes the ratio between the relative torsional angle caused by elastic deformation and the load. The greater the torsional stiffness, the smaller the torsional angle generated by the output shaft when subjected to external force, and the higher the positioning accuracy. Vibration acceleration refers to the acceleration caused by vibration phenomena caused by various internal and external factors during the operation of the reducer. The vibration acceleration reflects the stability and smoothness of the reducer during dynamic operation. Smaller vibration acceleration means that the harmonic reducer 1000 is more stable and smooth during operation, which helps to reduce wear and energy loss of the harmonic reducer 1000 and improve the overall performance and life of the reducer. At the same time, compared with the rigid wheel in the related art, the width of the inner tooth portion 110 of this embodiment is increased, which can increase the contact area with the outer tooth portion 210, reduce the tooth surface meshing surface pressure, and improve the load-bearing capacity of the harmonic reducer 1000.

[0059] from Figure 11As can be seen from the figure, as the value of Lc1 / Lc gradually increases, the torsional stiffness decreases gently within the range of 0.4 to 0.8, and the rate of decrease increases within the range of 0.8 to 1. The vibration acceleration decreases rapidly within the range of 0.4 to 0.75, and the rate of decrease is relatively gentle within the range of 0.75 to 1. When the value of Lc1 / Lc is less than 0.6, although the torsional stiffness is large, the vibration acceleration is also large, and the operating smoothness of the harmonic reducer 1000 deteriorates. When the value of Lc1 / Lc is greater than 0.9, the vibration acceleration is small, but the torsional stiffness is also small. Therefore, by rationally designing the value of Lc1 / Lc within the range of 0.6 to 0.9, it is possible to reduce the vibration acceleration while maintaining the torsional stiffness at an appropriate level, thereby improving the operating smoothness of the harmonic reducer 1000.

[0060] Reference Figure 1 and Figure 3 As shown, in the embodiment of the present invention, the maximum wall thickness of the thin-walled section 111 is Tc, and the maximum wall thickness Tc of the thin-walled section 111 refers to: along the radial direction of the rigid wheel 100, the thickness between the outer circumference of the thin-walled section 111 and the tooth top circle of the inner tooth portion 110. The inner hole diameter of the flexible wheel 200 is Df, which satisfies: 0.015*Df≤Tc≤0.05*Df. This formula is equivalent to 0.015≤Tc / Df≤0.05, for example, the value of Tc / Df can be 0.015, 0.02, 0.025, 0.03, 0.04, 0.05, etc. Among them, the inner hole diameter Df of the flexible wheel 200 is usually a constant value. The larger the maximum wall thickness Tc of the thin-walled section 111, the more difficult it is to produce elastic deformation. Refer to Figure 12 As shown, Figure 12 The horizontal axis in the graph represents the value of Tc / Df, the vertical axis on the left represents the stress of the rigid wheel 100, and the vertical axis on the right represents the vibration acceleration of the harmonic reducer 1000. When the value of Tc / Df is less than 0.015, although the vibration acceleration is small, the stress of the rigid wheel 100 is too small, and the overall strength of the rigid wheel 100 is low. When the value of Tc / Df is greater than 0.05, the vibration acceleration and the stress of the rigid wheel 100 are too high, the operating smoothness of the harmonic reducer 1000 is reduced, and the rigid wheel 100 has difficulty in generating elastic deformation to reduce interference with the external teeth 210, resulting in a reduced load-bearing capacity of the harmonic reducer 1000. To this end, by rationally designing the value of Tc / Df within the range of 0.015 to 0.05, the vibration acceleration can be reduced while ensuring that the stress of the rigid wheel 100 is within an appropriate range. While ensuring the strength of the rigid wheel 100, it is also given a certain elastic deformation ability, thereby reducing the interference between the rigid wheel 100 and the flexible wheel 200, thereby increasing the service life of the flexible wheel 200.

[0061] Reference Figure 3 and Figure 4As shown, in an embodiment of the present invention, the connection between the thin-walled section 111 and the first mounting portion 120 is constructed as a curve 130, which is composed of at least two arc segments. It can be understood that the smooth transition between the thin-walled section 111 and the first mounting portion 120 through the curve 130 can effectively reduce stress concentration at the connection between the thin-walled section 111 and the first mounting portion 120. When the curve 130 is composed of at least two arc segments, that is, the two arc segments have different radii or different angles, the connection between the thin-walled section 111 and the first mounting portion 120 can achieve a smoother transition, further reducing stress concentration and reducing adverse effects such as cracking at the connection between the thin-walled section 111 and the first mounting portion 120.

[0062] Continue to refer to Figure 3 and Figure 4 As shown, in an embodiment of the present invention, curve 130 connects to the outer side of thin-walled section 111 at point a, and curve 130 connects to first mounting portion 120 at point e. Along the axial direction of wave generator 300, the distance from point a to point e is Lwa, satisfying the following: 0.1*Lc1≤Lwa≤0.3*Lc1. This formula is equivalent to 0.1≤Lwa / Lc1≤0.3. For example, the value of Lwa / Lc1 can be 0.1, 0.15, 0.2, 0.25, 0.3, etc. The above formula reflects the range of the axial length of curve 130 in thin-walled section 111. When the value of Lwa / Lc1 is less than 0.1, that is, the axial length of curve 130 is short, it is difficult to reduce the stress at the connection between first mounting portion 120 and thin-walled section 111. When the value of Lwa / Lc1 is greater than 0.3, the axial length of curve 130 is too long, which is not conducive to the abutment fit between the inner bearing ring 420 and the outer wall of the thin-walled section 111, affecting the fitting accuracy. Therefore, by rationally designing the value of Lwa / Lc1 within the range of 0.1 to 0.3, the stress at the connection between the thin-walled section 111 and the first mounting portion 120 can be reduced while ensuring the abutment fit accuracy between the inner bearing ring 420 and the thin-walled section 111. This reduces stress concentration and improves the load-bearing capacity of the rigid wheel 100.

[0063] Reference Figure 4As shown, in the embodiment of the present invention, curve 130 has points b, c, and d. The distance from point a to point b is Lwb, the distance from point b to point c is Lwc, and the distance from point c to point d is Lwd. Lwb = Lwc = Lwd = Lwa / 4, i.e., curve 130 is divided into four equal parts in the axial direction. Along the radial direction of the rigid wheel 100, the distances from point b, point c, point d, and point e to point a are Lrb, Lrc, Lrd, and Lre, respectively. Lrb < Lrc < Lrd < Lre, satisfying the following: 0.1*Tc ≤ Lre ≤ 0.4*Tc, Lrb + Lrc + Lrd ≤ Lre / 2. Wherein, 0.1*Tc ≤ Lre ≤ 0.4*Tc is equivalent to 0.1 ≤ Lre / Tc ≤ 0.4. For example, the value of Lre / Tc can be 0.1, 0.2, 0.3, 0.4, etc. It is understood that when Lre / Tc is less than 0.1 and Lrb+Lrc+Lrd>Lre / 2, that is, the height of curve 130 in the radial direction of the rigid wheel 100 is relatively low, making it difficult to achieve a smooth transition at the connection between the thin-walled section 111 and the first mounting portion 120, and the effect of reducing stress concentration is not significant. When Lre / Tc is greater than 0.4, that is, the height of curve 130 in the radial direction of the rigid wheel 100 is relatively high, which is not conducive to the abutment and fit between the inner bearing ring 420 and the thin-walled section 111. Therefore, by rationally designing the value of Lre / Tc within the range of 0.1 to 0.4 and Lrb+Lrc+Lrd≤Lre / 2, stress concentration at the connection between the thin-walled section 111 and the first mounting portion 120 can be effectively reduced, while facilitating the abutment and fit between the inner bearing ring 420 and the thin-walled section 111 and improving installation efficiency.

[0064] Table 1: Comparison of the maximum stress at the connection between the thin-walled section 111 and the first mounting portion 120 for three different solutions

[0065]

[0066] In Table 1 above, Solution 1 directly connects the first mounting portion 120 and the thin-walled section 111 without providing the curve 130; Solution 2 connects the first mounting portion 120 and the thin-walled section 111 via a straight line; and Solution 3, the solution of this embodiment, connects the first mounting portion 120 and the thin-walled section 111 with the curve 130. As can be seen from the table above, the solution of this embodiment effectively reduces the maximum stress at the connection between the thin-walled section 111 and the first mounting portion 120, effectively avoiding stress concentration and thereby improving the load-bearing capacity of the rigid wheel 100.

[0067] Reference Figure 6As shown, in the embodiment of the present invention, the portion of the inner tooth portion 110 that axially protrudes beyond the first mounting portion 120 abuts against the inner side of the inner bearing ring 420. Therefore, the inner bearing ring 420 supports the inner tooth portion 110, preventing the inner tooth portion 110 from being subjected to excessive force and causing large-angle bending deformation, thereby improving the reliability of the rigid wheel 100. A protrusion 421 is provided at one axial end of the inner bearing ring 420. The protrusion 421 protrudes toward the first mounting portion 120, and the inner side of the protrusion 421 abuts against the outer side of the first mounting portion 120. It is understood that the provision of the protrusion 421 serves to position the rigid wheel 100 for installation. Furthermore, the protrusion 421 facilitates 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 concentrically positioned with the outer bearing ring 410. The outer surface of the oil seal 500 forms an interference fit with the inner bore of the outer bearing ring 410, while the inner bore of the oil seal 500 forms a sealing fit with the outer wall of the protrusion 421, enhancing the sealing effect. When the inner bearing ring 420 and the oil seal 500 rotate relative to each other, a radial contact seal is formed, effectively preventing the lubricant in the first and second grooves 430, 440 from escaping into the rigid wheel 100.

[0068] Reference Figure 7 As shown, in the embodiment of the present invention, the outer tooth portion 210 includes a plurality of convex teeth arranged along the circumference of the flexible wheel 200, and the convex teeth include a first tooth segment 211, a second tooth segment 212 and a third tooth segment 213 extending in the axial direction. From the outer tooth portion 210 to the flange portion 240, that is, Figure 7 From right to left in the figure, the first tooth segment 211, the third tooth segment 213, and the second tooth segment 212 are connected in sequence. The tooth tip diameter of the first tooth segment 211 gradually decreases in the direction away from the flange portion 240, while the tooth tip diameter of the second tooth segment 212 gradually decreases in the direction toward the flange portion 240. That is, the first tooth segment 211 and the second tooth segment 212 adopt a tooth profile modification scheme, where the tooth height of the first tooth segment 211 and the second tooth segment 212 gradually decreases in the direction away from the third tooth segment 213. Tooth height refers to the height in the radial direction. For example, the tooth tips of the first tooth segment 211 and the second tooth segment 212 can be inclined along a straight line, or can be an outward convex arc, an inward concave arc, etc. By setting the tooth height of the first tooth segment 211 and the second tooth segment 212 to gradually decrease, the interference between the tooth tips of the first tooth segment 211 and the second tooth segment 212 and the inner tooth portion 110 can be effectively reduced, thereby improving the service life of the flexible spline 200.

[0069] Continue to refer to Figure 7As shown, in the embodiment of the present invention, the diameter of the tooth top circle of the third tooth segment 213 is constant, that is, the tooth height of the third tooth segment 213 remains unchanged. Because the cylindrical portion 220 of the flexible wheel 200 becomes elliptical under the action of the wave generator 300 and has an opening angle, the motion trajectory of the outer tooth portion 210 is different under different cross-sections. The state of the third tooth segment 213 in the middle of the outer tooth portion 210 is optimal and less likely to interfere, while the outer tooth portion 210 is more likely to interfere with the inner tooth portion 110 at both ends along the axial direction. To this end, by designing the tooth height of the first tooth segment 211 and the tooth height of the second tooth segment 212 to gradually decrease in the direction away from the third tooth segment 213, the interference between the tooth tops of the first tooth segment 211 and the second tooth segment 212 and the inner tooth portion 110 can be effectively reduced.

[0070] Reference Figure 2 and Figure 8 As shown, in the embodiment of the present invention, the effective width of the flexspline 200 along a direction parallel to the rotation axis of the wave generator 300 is Lf. The effective width of the flexspline 200 refers to the minimum distance between the end surface of the cylindrical portion 220 facing away from the flange portion 240 and the flange portion 240. The tooth width of the external tooth portion 210 is Lf1, which satisfies the following conditions: 0.4*Lf≤Lf1≤0.6*Lf. For example, the values ​​of Lf1 can be 0.4*Lf, 0.45*Lf, 0.5*Lf, 0.55*Lf, or 0.6*Lf. The width of the first tooth segment 211 is Lf2, which satisfies the following conditions: 0.2*Lf1≤Lf2≤0.35*Lf1. For example, the values ​​of Lf2 can be 0.2*Lf1, 0.23*Lf1, 0.24*Lf1, 0.25*Lf1, 0.3*Lf1, or 0.35*Lf1. The width of the third tooth segment 213 is Lf3, which satisfies the following: 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, or 0.45*Lf1. The width of the second tooth segment 212 is Lf4, which satisfies the following: 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.

[0071] It is understood that the widths of the first tooth segment 211, the third tooth segment 213, and the second tooth segment 212 affect the meshing effect with the inner tooth portion 110. When Lf1 is less than 0.4*Lf, the tooth width of the outer tooth portion 210 is short, the effective meshing area between the outer tooth portion 210 and the inner tooth portion 110 is reduced, and meshing stability deteriorates. When Lf1 is greater than 0.6*Lf, the tooth width of the outer tooth portion 210 is long, increasing the volume of the harmonic accelerator and hindering compact design. When Lf2 is less than 0.2*Lf1, the width of the first tooth segment 211 is small, which can easily interfere with the inner tooth portion 110. When Lf2 is greater than 0.4*Lf1, the width of the first tooth segment 211 is large. While the width of the outer tooth portion 210 remains unchanged, the width of the third tooth segment 213 needs to be shortened accordingly, resulting in a reduction in the effective meshing area between the outer tooth portion 210 and the inner tooth portion 110 and deteriorating meshing stability. When Lf3 is less than 0.35*Lf1, meaning the width of the third tooth segment 213 is too small, this also reduces the effective meshing area between the outer tooth portion 210 and the inner tooth portion 110, resulting in poor meshing stability. When Lf3 is greater than 0.45*Lf1, while the width of the outer tooth portion 210 remains unchanged, the widths of the first tooth segment 211 and the second tooth segment 212 must be reduced accordingly, potentially leading to interference with the inner tooth portion 110 at these locations. When Lf4 is less than 0.25*Lf1, meaning the width of the second tooth segment 212 is too small, it can easily interfere with the inner tooth portion 110. When Lf4 is greater than 0.45*Lf1, meaning the width of the second tooth segment 212 is too large, while the width of the outer tooth portion 210 remains unchanged, the width of the third tooth segment 213 must be reduced accordingly, resulting in a reduced effective meshing area between the outer tooth portion 210 and the inner tooth portion 110, resulting in poor meshing stability.

[0072] Therefore, the ratio of the tooth width of the outer tooth portion 210 to the effective width of the flexible spline 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 outer tooth portion 210 is between 0.2 and 0.35, the ratio of the width of the third tooth segment 213 to the width of the outer tooth portion 210 is between 0.35 and 0.45, and the ratio of the width of the second tooth segment 212 to the width of the outer tooth portion 210 is between 0.25 and 0.4. While ensuring the meshing stability of the outer tooth portion 210 and the inner tooth portion 110, the interference between the outer tooth portion 210 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 spline 200.

[0073] Reference Figure 8As shown, in the embodiment of the present invention, the inclination angle of the first tooth segment 211 is α1, and the inclination angle of the second tooth segment is β1. It should be noted that the inclination angle α1 of the first tooth segment 211 refers to: the tooth top 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 the angle between the first inclined surface 2111 and the rotation axis is α1. The inclination angle β1 of the second tooth segment refers to: the tooth top of the second tooth segment 212 is configured as a second inclined surface 2112, the second inclined surface 2112 is inclined in a direction away from the third tooth segment 213 and toward the rotation axis, and the angle between the second inclined surface 2112 and the rotation axis is β1.

[0074] The inclination angle α1 of the first tooth segment 211 and the inclination angle β1 of the second tooth segment satisfy the following conditions: 0.3° ≤ α1 ≤ 1°, 0.3° ≤ β1 ≤ 1°, and β1 < α1. For example, the value of α1 can be 0.3°, 0.4°, 0.6°, 0.7°, 0.9°, or 1°; for example, the value of β1 can be 0.3°, 0.4°, 0.6°, 0.7°, 0.9°, or 1°. When α1 is less than 0.3°, the inclination angle of the first bevel 2111 is too small, making it difficult to reduce interference between the inner and outer teeth 110, 210. When α1 is greater than 1°, the effective meshing area of ​​the first tooth segment 211 and the inner tooth 110 is reduced, resulting in poor meshing stability. When β1 is less than 0.3°, the inclination angle of the second bevel 2112 is too small, making it difficult to reduce interference between the inner and outer teeth 110, 210. When β1 is greater than 1°, the effective area of ​​the second tooth segment 212 and the inner tooth portion 110 during meshing is likely to be reduced, thereby causing poor meshing stability.

[0075] It is understandable that because the second tooth segment 212 is closer to the thin-walled section 111, the thin-walled section 111 can drive the second tooth segment 212 to produce a certain degree of elastic deformation, thereby reducing the interference between the outer tooth portion 210 of the flexspline 200 and the second tooth segment 212. Since the first tooth segment 211 is closer to the first mounting portion 120, it is more likely to interfere with the outer tooth portion 210. Therefore, by setting β1 < α1, the interference between the inner tooth portion 110 and the outer tooth portion 210 can be effectively reduced, thereby improving the stability of power transmission.

[0076] Continue to refer to Figure 8As shown, in an embodiment of the present invention, in order to further reduce interference between the outer tooth portion 210 and the inner tooth portion 110, a third inclined surface 2121 is provided between two adjacent first tooth segments 211. The third inclined surface 2121 is inclined in a direction away from the third tooth segment 213 and toward the rotation axis. 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. The inclination angle of the third inclined surface 2121 and the inclination angle of the first inclined surface 2111 can be the same or different, and the inclination angle of the fourth inclined surface 2122 and the inclination angle of the second inclined surface 2112 can be the same or different. This can effectively reduce or avoid interference between the tooth tops of the inner tooth portion 110 and the tooth roots of the outer tooth portion 210, thereby reducing friction and wear on the tooth surfaces and extending the life of the flexible spline 200.

[0077] Continue to refer to Figure 8 As shown, in the embodiment of the present invention, the inclination angle of the third inclined surface 2121 is α2, which satisfies: 0.3°≤α2≤1.0°. For example, the value of α2 can be 0.3°, 0.4°, 0.6°, 0.7°, 0.9°, or 1.0°. When α2 is less than 0.3°, that is, the inclination angle of the third inclined surface 2121 is too small, it is difficult to reduce the interference between the inner tooth portion 110 and the outer tooth portion 210. When α2 is greater than 1°, it is easy to cause the strength of the outer tooth portion 210 to decrease, and it is easy to cause tearing between adjacent convex teeth. 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 210, improve the service life of the flexible wheel 200, and at the same time ensure that the outer tooth portion 210 has appropriate strength and high reliability.

[0078] Continue to refer to Figure 8 As shown, in the embodiment of the present invention, the inclination angle of the fourth inclined surface 2122 is β2, which satisfies the following: 0°≤β2≤0.4°. For example, the value of β2 can be 0.1°, 0.2°, 0.3°, or 0.4°. When β2 is greater than 0.4°, the strength of the outer tooth portion 210 is likely to be reduced, and tears are likely to occur between adjacent protruding teeth. Therefore, the reasonable design of the sizes of β1 and β2 can effectively reduce the interference between the inner tooth portion 110 and the outer tooth portion 210, improve the service life of the flexible wheel 200, and at the same time ensure that the outer tooth portion 210 has appropriate strength and high reliability.

[0079] Table 2: Comparison of tooth surface contact area of ​​different schemes

[0080]

[0081] For example, referring to Table 2 above, Solution 1 is a solution from the related art, with Lc = 0.42*Lf, Lf1 = 0.36*Lf, and the tooth height of the outer tooth portion 210 remains unchanged, that is, no tooth profile modification is used. Solution 2 is Lc = 0.55*Lf, Lf1 = 0.5*Lf, and the tooth height of the outer tooth portion 210 remains unchanged, that is, no tooth profile modification is used. Solution 3 is Lc = 0.55*Lf, Lf1 = 0.5*Lf, and the first tooth segment 211 and the second tooth segment 212 of the outer tooth portion 210 adopt a profile modification solution. As can be seen from Table 1 above, the design of Lc = 0.55*Lf and Lf1 = 0.5*Lf can increase the tooth surface contact area by 19.2%. On this basis, adding the profile modification solution increases the improvement by 38.5% compared to Solution 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.

[0082] The inner diameter of the flexible wheel 200 of the same specification is the same, and the outer dimensions are basically the same. When the reduction ratio of the harmonic reducer 1000 is different, the number of teeth and the module of the flexible wheel 200 are usually different, so that the stress on the flexible wheel 200 when deforming is also different. In order to reduce the stress on the flexible wheel 200 when deforming and simplify the design of the flexible wheel 200 of the same specification but different reduction ratios, refer to Figure 1 and Figure 5 As shown, in the embodiment of the present invention, the tooth root wall thickness of the flexspline 200 is Tf, and the tooth root wall thickness Tf refers to the distance between the tooth root of the outer tooth portion 210 and the inner hole wall of the flexspline 200 along the radial direction of the flexspline 200. The inner hole diameter of the flexspline 200 is Df, and the reduction ratio of the harmonic reducer 1000 is R, which satisfies: 0.0043ln(R)-0.0061≤Tf / Df≤0.005ln(R)-0.0036, wherein the reduction ratio R can be obtained from the parameters marked on the nameplate of the harmonic reducer 1000. Figure 13 As shown, Figure 13 The horizontal axis of the graph represents the value of Tf / Df, and the vertical axis represents the root stress of the flexspline 200. As can be seen from the graph, as the value of Tf / Df gradually increases, the root stress of the flexspline 200 first decreases and then increases, reaching a minimum value. Therefore, for flexsplines 200 of the same specification but different reduction ratios, using the natural logarithm function Ln(R) to eliminate the influence of the reduction ratio R, it is only necessary to ensure that the value of Tf / Df is limited to the ranges of 0.0043ln(R)-0.0061 and 0.005ln(R)-0.0036. This effectively reduces the stress on the flexspline 200, simplifies the design of the flexspline 200, and thus improves production efficiency. Furthermore, compared to flexsplines in related arts, the increased root wall thickness Tf of the flexspline 200 in this embodiment can effectively improve the load-bearing capacity and torsional stiffness of the harmonic reducer 1000.

[0083] Reference Figure 2 As shown, in the embodiment of the present invention, along the axial direction of the wave generator 300, the effective width of the flexible wheel 200 is Lf. The effective width of the flexible wheel 200 refers to the minimum distance between the end face of the end of the cylinder 220 facing away from the flange 240 and the flange 240. The width of the inner tooth portion 110 is Lc. The width of the inner tooth portion 110 refers to the maximum length of the inner tooth portion 110 along the axial direction, for example, the distance between the two farthest end faces of the rigid wheel 100 along the axial direction. The relationship between Lf and Lc satisfies: 0.45*Lf≤Lc≤0.65*Lf. Among them, the value of Lc can be 0.45*Lf, 0.5*Lf, 0.51*Lf, 0.53*Lf, 0.55*Lf, 0.58*Lf, 0.65*Lf. When Lc is less than 0.45*Lf, that is, the maximum length of the inner tooth portion 110 is short, resulting in a decrease in the tooth surface contact area between the inner tooth portion 110 and the outer tooth portion 210, an increase in contact stress, and a reduction in the load-bearing capacity of the harmonic reducer 1000. When Lc is greater than 0.65*Lf, that is, the maximum length of the inner tooth portion 110 is large, occupying too much space and having a large strength margin, which is not conducive to the miniaturization design of the harmonic reducer 1000. Therefore, a reasonable design of the difference between 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 210, reduce contact stress, improve the load-bearing capacity of the harmonic reducer 1000, and at the same time be conducive to the miniaturization design of the harmonic reducer 1000.

[0084] Reference Figure 6 、 Figure 9 and Figure 10 As shown, in the embodiment of the present invention, the outer bearing ring 410 includes a second mounting portion 411 and a raised portion 412 connected to the inner side of the second mounting portion 411. The raised portion 412 has first and second outer raceways 413 and 414 at opposite ends along the axial direction. The raised portion 412 enhances the structural strength of the first and second outer raceways 413 and 414, effectively reducing their deformation. It also acts as a position limiter for the first and second rolling elements 431 and 441, preventing contact between them. The outer side of the inner bearing ring 420 is provided with a groove 422, located opposite the raised portion 412. The groove 422 has first and second inner raceways 423 and 424 at its axial ends. The first inner raceway 423 and the first outer raceway 413 are arranged opposite each other to form a first groove 430. The second inner raceway 424 and the second outer raceway 414 are arranged opposite each other to form a second groove 440. The above solution is advantageous for installing the first rolling element 431 and the second rolling element 441 , thereby improving assembly efficiency and enabling the first rolling element 431 and the second rolling element 441 to rotate smoothly, thereby improving the stability of the support bearing 400 .

[0085] Reference Figure 6 As shown, in the embodiment of the present invention, a gap is provided between the protrusion 412 and the bottom wall of the groove 422, and the first groove body 430 and the second groove body 440 are connected through the gap. It can be understood that by providing the first groove body 430 and the second groove body 440 with communication through the gap, lubricating oil is facilitated to flow within the first groove body 430 and the second groove body 440, thereby lubricating the first rolling element 431 and the second rolling element 441, thereby improving the smoothness of the rolling of the first rolling element 431 and the service life of the second rolling element 441.

[0086] Continue to refer to Figure 6 As shown, in an embodiment of the present invention, the inner bearing ring 420 includes a first ring body 425 and a second ring body 426 connected to each other. The first ring body 425 and the second ring body 426 are arranged in a left-to-right direction and connected by fasteners. A step is provided on the side of the first ring body 425 facing the second ring body 426, and the second ring body 426 is positioned and connected to the step. The step serves as a positioning function, thereby facilitating the connection between the first and second ring bodies 425 and 426. The first inner raceway 423 is located outside the first ring body 425 and adjacent to the second ring body 426. The second inner raceway 424 is located outside the second ring body 426 and away from the first ring body 425. The second ring body 426 is connected to the rigid wheel 100. Designing the inner bearing ring 420 so that the first and second ring bodies 425 and 426 are connected facilitates the installation of the first and second rolling elements 431 and 441, reducing assembly difficulty.

[0087] Continue to refer to Figure 6 As shown, in this embodiment of the present invention, the outer side of the thin-walled section 111 abuts the inner side of the second ring body 426. Along the axial direction of the wave generator 300, the end of the second ring body 426 away from the first ring body 425 abuts the end of the first mounting portion 120 facing the thin-walled section 111, thereby positioning the second ring body 426, facilitating assembly of the second ring body 426, and improving assembly efficiency.

[0088] An industrial robot according to one embodiment of the present invention includes a motor and the harmonic reducer 1000 of the above embodiment. It is understood that the motor may be a servo motor, which drives and connects to the harmonic reducer 1000 to control the deceleration of the joints of the industrial robot. The industrial robot may be a handling robot, a welding robot, an assembly robot, a processing robot, a painting robot, a cleaning robot, a collaborative robot, or the like.

[0089] The industrial robot of the present invention employs the harmonic reducer 1000 of the aforementioned embodiment. By positioning the wave generator 300 within the flexspline 200 and partially meshing the outer teeth 210 of the flexspline 200 with the inner teeth 110 of the rigid spline 100, rotation of the wave generator 300 drives relative rotation between the flexspline 200 and the rigid spline 100. 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 accommodates a first rolling element 431, while the second groove 440 accommodates a second rolling element 441. The first groove 430 and the second groove 440 are spaced apart along the axial direction of the wave generator 300. The provision of two sets of rolling elements effectively enhances the load-bearing capacity of the harmonic reducer 1000, improving the assembly efficiency between the bearing assembly, the rigid spline 100, and the flexspline 200 while maintaining the overall compactness of the structure. Because the rigid wheel 100 includes a first mounting portion 120 and an inner tooth portion 110 that are connected, and the first mounting portion 120 is located at the end of the inner tooth portion 110 that faces away from the inner bearing ring 420, the inner bearing ring 420 can extend to the outer wall of the inner tooth portion 110, and the overall length of the inner bearing ring 420 is relatively long. Providing mounting holes in the inner bearing ring 420 minimizes the impact on the raceway, thereby reducing the difficulty of machining the support bearing 400. At the same time, because the inner tooth portion 110 protrudes from the first mounting portion 120, the inner tooth portion 110 has a thin-walled design and can produce a certain degree of elastic deformation. Therefore, without reducing the meshing depth between the inner tooth portion 110 and the outer tooth portion 210, the elastic deformation of the inner tooth portion 110 is used to reduce interference with the outer tooth portion 210, thereby improving the load-bearing capacity of the harmonic reducer 1000 and reducing vibration and noise.

[0090] 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.

[0091] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by 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, comprising a first mounting portion and an inner tooth portion connected to an inner side of the first mounting portion; A flexible spline is provided inside the rigid spline, and the flexible spline includes an external tooth portion; a wave generator disposed inside the flexspline and configured to partially mesh the outer tooth portion with the inner tooth portion; a support bearing configured to enable the rigid wheel and the flexible wheel to rotate relative to each other, the support bearing comprising an outer bearing ring and an inner bearing ring disposed within the outer bearing ring, a first groove body for mounting a first rolling element and a second groove body for mounting a second rolling element being disposed between the inner bearing ring and the outer bearing ring, the first groove body and the second groove body being spaced apart along the axial direction of the wave generator; In which, the first mounting portion is connected to the inner bearing ring, and along the axial direction of the wave generator, the first mounting portion is connected to the end of the inner tooth portion facing away from the inner bearing ring, and the inner tooth portion includes a thin-walled section protruding from the first mounting portion, the width of the thin-walled section is Lc1, and the width of the inner tooth portion is Lc, satisfying: 0.6*Lc≤Lc1≤0.9*Lc.

2. The harmonic reducer according to claim 1, characterized in that: The maximum wall thickness of the thin-walled section is Tc, and the inner hole diameter of the flexible wheel is Df, which satisfies the following conditions: 0.015*Df≤Tc≤0.05*Df.

3. The harmonic reducer according to claim 1 or 2, characterized in that: The connection between the thin-walled section and the first mounting portion is constructed as a curve, which is composed of at least two arc segments. The curve is connected to the outer side of the thin-walled section at point a, and the curve is connected to the first mounting portion at point e. Along the axial direction, the distance from point a to point e is Lwa, satisfying: 0.1*Lc1≤Lwa≤0.3*Lc1.

4. The harmonic reducer according to claim 3, characterized in that: The curve has points b, c and d, the distance from point a to point b is Lwb, the distance from point b to point c is Lwc, the distance from point c to point d is Lwd, and Lwb=Lwc=Lwd=Lwa / 4; Along the radial direction of the rigid wheel, the distances between point b, point c, point d, point e and point a are Lrb, Lrc, Lrd, and Lre respectively, Lrb<Lrc<Lrd<Lre, satisfying: 0.1*Tc≤Lre≤0.4*Tc, Lrb+Lrc+Lrd≤Lre / 2.

5. The harmonic reducer according to claim 1, characterized in that: The flexible spline also includes a cylinder, a diaphragm and a flange. The external tooth portion is connected to the outer side of one end of the cylinder, the diaphragm is connected to the other end of the cylinder and extends radially along the cylinder, the flange is connected to the end of the diaphragm away from the cylinder, and the flange is fixedly connected to the outer bearing ring.

6. The harmonic reducer according to claim 5, characterized in that: Along the axial direction, the external tooth portion includes a first tooth segment away from one end of the flange portion and a second tooth segment close to one end of the flange portion, the diameter of the tooth top circle of the first tooth segment gradually decreases in the direction away from the flange portion, and the diameter of the tooth top circle of the second tooth segment gradually decreases in the direction toward the flange portion.

7. The harmonic reducer according to claim 6, characterized in that: The outer tooth portion further includes a third tooth segment located between the first tooth segment and the second tooth segment, and a diameter of a tooth tip circle of the third tooth segment is constant.

8. The harmonic reducer according to claim 7, characterized in that: Along the axial direction, the effective width of the flexspline is Lf, the width of the outer tooth portion is Lf1, the width of the first tooth segment is Lf2, the width of the second tooth segment is Lf4, and the width of the third tooth segment is Lf3, 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.

9. The harmonic reducer according to claim 6, characterized in that: The inclination angle of the first tooth segment is α1, and the inclination angle of the second tooth segment is β1, which satisfies: 0.3°≤α1≤1.0°, 0°≤β1≤0.4°, and β1<α1.

10. The harmonic reducer according to claim 1, characterized in that: The tooth root wall thickness of the flexspline is Tf, the inner hole diameter of the flexspline is Df, and the reduction ratio of the harmonic reducer is R, which satisfies: 0.0043ln(R)-0.0061≤Tf / Df≤0.005ln(R)-0.0036.

11. The harmonic reducer according to claim 1, characterized in that: Along the axial direction, the effective width of the flexible spline is Lf, which satisfies: 0.45*Lf≤Lc≤0.65*Lf.

12. The harmonic reducer according to claim 1, characterized in that: The outer bearing ring includes a second mounting portion and a raised portion connected to the inner side of the second mounting portion, and the raised portion is provided with a first outer raceway and a second outer raceway in opposite directions at two ends along the axial direction. The outer side of the inner bearing ring is provided with a groove arranged opposite to the protrusion, and the two ends of the groove along the axial direction are respectively a first inner raceway and a second inner raceway; The first inner raceway and the first outer raceway are arranged opposite to each other and form the first groove body, and the second inner raceway and the second outer raceway are arranged opposite to each other and form the second groove body.

13. The harmonic reducer according to claim 12, characterized in that: There is a gap between the protrusion and the bottom wall of the groove, and the first groove body and the second groove body are connected through the gap.

14. The harmonic reducer according to claim 12, characterized in that: The inner bearing ring includes a first ring body and a second ring body connected to each other, the first inner raceway is arranged on the outside of the first ring body and close to the second ring body, the second inner raceway is arranged on the outside of the second ring body and away from the first ring body, and the second ring body is connected to the rigid wheel.

15. The harmonic reducer according to claim 14, characterized in that: The outer side of the thin-walled section abuts against the inner side of the second ring body; along the axial direction, one end of the second ring body away from the first ring body abuts against one end of the first mounting portion facing the thin-walled section.

16. An industrial robot, characterized in that: The invention comprises the harmonic reducer according to any one of claims 1 to 15.

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