Harmonic reducer and robot

Abstract

The invention provides a harmonic reducer and a robot, and relates to the field of harmonic transmission, the harmonic reducer comprises a cross bearing, a rigid gear, a flexible gear, a cross slide block and a wave generator; the cross bearing comprises a bearing inner ring and a bearing outer ring, and a first groove is formed in the end face of the bearing inner ring; the flexible gear is a cup-shaped flexible gear, and a second groove is formed in the cup bottom; the cross-shaped sliding block comprises a connecting disc, a first convex block and a second convex block, the first convex block is located on the first end face of the connecting disc, the second convex block is located on the second end face of the connecting disc, an included angle is formed between the length direction of the first convex block and the length direction of the second convex block, the first convex block is clamped with the first groove, and the second convex block is clamped with the second groove; the cross section of the first protruding block and the cross section of the second protruding block are trapezoid, the sides, connected with the connecting disc, of the first protruding block and the second protruding block are trapezoid upper bottoms, the first groove is matched with the first protruding block in shape, and the second groove is matched with the second protruding block in shape. The problems that installation is tedious and concentricity is difficult to adjust due to the fact that the flexible gear and the crossed bearing inner ring are connected through screws are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of harmonic transmission, in particular to a harmonic reducer and a robot. BACKGROUND

[0002] The harmonic reducer is generally composed of a rigid gear, a flexible gear, a wave generator, a cross bearing and the like, is a high-precision and high-torque transmission device, and is widely used in the fields of robots, industrial automation and precision equipment. Among them, the cup-type harmonic reducer with a cup-type flexible gear is more widely used due to its compact structure.

[0003] In the related art, the connection between the flexible gear and the inner ring of the cross bearing of the cup-type harmonic reducer generally adopts a screw fastening mode. During assembly, the hole positions need to be accurately aligned, and then the screws are tightened one by one, and the torque needs to be controlled by a torque wrench. This not only makes the installation process cumbersome, but also makes the flexible gear eccentric due to uneven screw tightening torque. In addition, the screw fastening connection cannot compensate for the radial deviation generated during assembly, and additional concentricity measurement and adjustment are required, which is difficult to control the precision and affects the assembly efficiency and transmission stability.

[0004] Therefore, how to solve the problem that the connection between the flexible gear and the inner ring of the cross bearing in the cup-type harmonic reducer through screws leads to complicated installation and difficult concentricity adjustment. SUMMARY

[0005] Therefore, the present application provides a harmonic reducer and a robot to solve the problem that the connection between the flexible gear and the inner ring of the cross bearing in the cup-type harmonic reducer through screws leads to complicated installation and difficult concentricity adjustment.

[0006] In order to achieve the above purpose, the present application provides the following technical solutions: A harmonic reducer, comprising: a cross bearing comprising a bearing inner ring and a bearing outer ring, an end surface of the bearing inner ring being provided with a first groove extending in a radial direction, and the first groove being provided with a pair of opposite grooves in the radial direction; a rigid gear fastened to the bearing outer ring; a flexible gear sleeved on the rigid gear, and outer teeth of the flexible gear being engaged with inner teeth of the rigid gear, the flexible gear being a cup-type flexible gear and a cup bottom of the cup-type flexible gear being provided with a second groove extending in a radial direction, and the second groove being provided with a pair of opposite grooves in the radial direction; The cross slider comprises a connecting disc, a first protrusion and a second protrusion, the first protrusion is located at a first end surface of the connecting disc, the first protrusion extends radially and is provided with a pair of radially opposite protrusions, the second protrusion is located at a second end surface of the connecting disc, the second protrusion extends radially and is provided with a pair of radially opposite protrusions, the length direction of the first protrusion and the length direction of the second protrusion have an included angle, the first protrusion is engaged with the first groove, and the second protrusion is engaged with the second groove, so that the flexible gear and the bearing inner ring are assembled and connected through the cross slider. The wave generator is sleeved in the flexible gear. The cross section of the first protrusion and the second protrusion is a trapezoid, and the side connected with the connecting disc is the upper base of the trapezoid, the first groove is matched with the shape of the first protrusion, and the second groove is matched with the shape of the second protrusion.

[0007] Optionally, the matching gap of the first protrusion and the first groove, and the matching gap of the second protrusion and the second groove are all δ, 0.015mm≤δ≤0.035mm.

[0008] Optionally, the cross section of the first protrusion and the second protrusion is an isosceles trapezoid, and the base angle is α, wherein: 76°≤α≤80°; and / or, The cross section of the first groove and the second groove is an isosceles trapezoid, and the base angle is α', and the matching tolerance of α' and α is ±0.5°.

[0009] Optionally, the height of the first protrusion and the second protrusion protruding relative to the connecting disc is H, 1.3mm≤H≤2mm.

[0010] Optionally, the diameter of the connecting disc is D, the span of the pair of first protrusions in the radial direction of the connecting disc, and the span of the pair of second protrusions in the radial direction of the connecting disc are all L, 0.68×D≤L≤0.72×D.

[0011] Optionally, the height of the first protrusion and the second protrusion protruding relative to the connecting disc is H; The cross section of the first protrusion and the second protrusion is an isosceles trapezoid, the upper base width of the cross section of the first protrusion and the second protrusion is b1, the lower base width of the cross section of the first protrusion and the second protrusion is b2, 0.8×H≤b1≤0.9×H, 0.8mm≤b2-b1≤1.2mm; The depth of the first groove and the second groove in the axial direction of the harmonic reducer is h, 0.03mm≤h-H≤0.05mm; The groove bottom width of the first groove and the second groove is b3, b3=b2+2×δ, 0.015mm≤δ≤0.035mm.

[0012] Optionally, the end portion of the first protrusion and the second protrusion located at the radial outside has a rounded corner structure and a radius r, 0.2mm≤r≤0.4mm.

[0013] Optionally, the surface average roughness of the first protrusion and the second protrusion is less than or equal to 0.4μm; and / or, The surface average roughness of the first groove and the second groove is less than or equal to 0.4μm.

[0014] Optionally, the cup bottom of the flexspline has a connecting boss, the second groove is opened in the connecting boss, and the connecting disc is in diameter adaptation with the connecting boss and has a diameter tolerance of H7. The end face circle runout tolerance of the connecting disc is less than or equal to 0.003mm.

[0015] Optionally, the top of the first protrusion and the top of the second protrusion are configured to have elasticity; or, The groove bottom of the first groove and the groove bottom of the second groove are configured to have elasticity.

[0016] A robot comprising the harmonic reducer in any of the above.

[0017] The harmonic reducer provided by the application comprises a cross bearing, a rigid wheel, a flexible wheel, a cross slider and a wave generator. The cross bearing comprises a bearing inner ring and a bearing outer ring. An end surface of the bearing inner ring is provided with a first groove extending in a radial direction, and the first groove is provided with a pair of grooves opposite in the radial direction. The rigid wheel is tightly connected with the bearing outer ring. The flexible wheel is sleeved in the rigid wheel, and the outer gear of the flexible wheel is engaged with the inner gear of the rigid wheel. The flexible wheel is a cup-shaped flexible wheel, and the cup bottom is provided with a second groove extending in the radial direction, and the second groove is provided with a pair of grooves opposite in the radial direction. The cross slider comprises a connecting disc, a first protrusion and a second protrusion. The first protrusion is located on the first end surface of the connecting disc, extends in the radial direction and is provided with a pair of protrusions opposite in the radial direction. The second protrusion is located on the second end surface of the connecting disc, extends in the radial direction and is provided with a pair of protrusions opposite in the radial direction. The length direction of the first protrusion and the length direction of the second protrusion have an included angle. The first protrusion is engaged with the first groove, and the second protrusion is engaged with the second groove, so that the flexible wheel and the bearing inner ring are assembled and connected through the cross slider. The wave generator is sleeved in the flexible wheel. The cross section of the first protrusion and the second protrusion is a trapezoid, and the side connected with the connecting disc is the upper base of the trapezoid. The shape of the first groove is matched with the shape of the first protrusion, and the shape of the second groove is matched with the shape of the second protrusion. In this way, the flexible wheel is a cup-shaped flexible wheel, that is, the harmonic reducer provided by the application is a cup-shaped harmonic reducer. In the application, the traditional way of tightly connecting the flexible wheel and the bearing inner ring through a screw is not used, but a plug-in connection is formed through the cross slider. During assembly, the first protrusion of the cross slider is slid into the first groove of the bearing inner ring from the side (that is, in the radial direction), and then the flexible wheel is connected with the cross slider, that is, the second groove of the cup bottom of the flexible wheel is sleeved on the second protrusion. The protrusions and the corresponding grooves are trapezoidal shapes matched in shape, which is simple to operate and convenient to install, improves the assembly efficiency, and avoids the torque unevenness caused by the screw tight connection. The cross slider provided by the application has a dual-function design. Since the cross sections of the first protrusion and the first groove are trapezoids with narrower roots and are matched, and the cross sections of the second protrusion and the second groove are trapezoids with narrower roots and are matched, the cross slider can be prevented from moving axially without additional fasteners. Not only can the flexible wheel and the cross bearing be prevented from being separated in the axial direction, but also the high-speed running scene of the harmonic reducer can be adapted. Moreover, since all the protrusions and the corresponding grooves have trapezoidal slopes, the trapezoidal slopes can be used as guides during assembly to automatically fine-tune the position of the flexible wheel, realize automatic centering and concentricity adjustment, and meet the concentricity requirement of the harmonic reducer transmission, thereby solving the problem that the flexible wheel and the cross bearing inner ring are connected through a screw in the cup-shaped harmonic reducer of the prior art, which causes complicated installation and difficult concentricity adjustment. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description only need to be used to explain the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0019] Figure 1 The assembly process schematic diagram of the cross bearing and the cross slider provided by the embodiments of the present application.

[0020] Figure 2 The cross-sectional view of the harmonic reducer provided by the embodiments of the present application.

[0021] Figure 3 The front view of the cross slider provided by the embodiments of the present application.

[0022] Figure 4 The side view of the cross slider provided by the embodiments of the present application.

[0023] Figure 5 The cross-sectional view of the flexspline provided by the embodiments of the present application.

[0024] Figure 6 The front view of the flexspline provided by the embodiments of the present application.

[0025] In Figures 1-6 , the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description only need to be used to explain the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor. 1, bearing inner ring; 2, bearing outer ring; 3, rigid wheel; 4, flexspline; 5, cross slider; 6, flexible bearing; 7, cam; 8, first screw; 51, first protrusion; 52, second protrusion; 53, connecting disc; 101, first groove; 41, connecting boss; 401, second groove. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0027] In the structural design of harmonic reducer, the cross slider coupling has more applications in harmonic reducer due to its simple structure and the characteristics of compensating radial displacement. The cross slider coupling realizes torque transmission and deviation compensation through the sliding of the intermediate slider in the groove. However, the applicant finds that the intermediate slider of the conventional cross slider coupling adopts a rectangular cross section, which is prone to axial shedding and is not optimized in size for the assembly requirements of the harmonic reducer. For the cup-type harmonic reducer, it cannot directly adapt to the connection scene of the flexspline and the inner ring of the cross bearing. Therefore, it is urgent to design a connection structure that is suitable for the cup-type harmonic reducer and has the functions of anti-falling and concentric adjustment, to solve the problems of complicated installation and difficult concentricity adjustment caused by screw connection of the flexspline and the inner ring of the cross bearing.

[0028] Based on the above research ideas, as shown in Figures 1-6 The embodiment of the present application provides a harmonic reducer, which comprises a cross bearing, a rigid wheel 3, a flexible wheel 4, a cross slider 5 and a wave generator. The cross bearing comprises a bearing inner ring 1 and a bearing outer ring 2. The end face of the bearing inner ring 1 is provided with a first groove 101 extending in the radial direction, and the first groove 101 is provided with a pair of radially opposite grooves. The rigid wheel 3 is tightly connected with the bearing outer ring 2 through a first screw 8. The flexible wheel 4 is sleeved in the rigid wheel 3, and the outer teeth of the flexible wheel 4 are engaged with the inner teeth of the rigid wheel 3. The flexible wheel 4 is a cup-type flexible wheel, and the cup bottom is provided with a second groove 401 extending in the radial direction, and the second groove 401 is provided with a pair of radially opposite grooves. The cross slider 5 comprises a connecting disc 53, a first protrusion 51 and a second protrusion 52. The first protrusion 51 is located on the first end face of the connecting disc 53, and the first protrusion 51 extends in the radial direction and is provided with a pair of radially opposite protrusions. The second protrusion 52 is located on the second end face of the connecting disc 53, and the second protrusion 52 extends in the radial direction and is provided with a pair of radially opposite protrusions. The length direction of the first protrusion 51 and the length direction of the second protrusion 52 have an included angle. The first protrusion 51 is engaged with the first groove 101, and the second protrusion 52 is engaged with the second groove 401, so that the flexible wheel 4 and the bearing inner ring 1 are connected through the cross slider 5 to realize torque transmission. The wave generator is sleeved in the flexible wheel 4, and the wave generator comprises a flexible bearing 6 and a cam 7 sleeved in the flexible bearing 6. The cross section of the first protrusion 51 and the second protrusion 52 is trapezoidal, and the side of the first protrusion 51 / second protrusion 52 connected with the connecting disc 53 is the upper base of the trapezoid, and the other side is the lower base of the trapezoid. The size of the lower base of the trapezoid is greater than that of the upper base of the trapezoid. The first groove 101 and the first protrusion 51 are shape-adapted, and the second groove 401 and the second protrusion 52 are shape-adapted. That is, the cross section of the first protrusion 51 and the second protrusion 52 is constructed as a limited axial positioning feature of the connecting disc 53, which cannot be separated from the first groove 101 and the second groove 401 in the axial direction.

[0029] With this configuration, the flexible wheel 4 is a cup-shaped flexible wheel, meaning the harmonic reducer provided in this application is a cup-shaped harmonic reducer. This application no longer uses the traditional method of fastening the flexible wheel 4 and the bearing inner ring 1 with screws; instead, it uses a cross slider 5 to form a plug-in connection. During assembly, the first protrusion 51 of the cross slider 5 is slid into the first groove 101 of the bearing inner ring 1 from the side (i.e., radially), and then the flexible wheel 4 is connected to the cross slider 5. That is, the second groove 401 at the bottom of the flexible wheel 4 slides onto the second protrusion 52. All protrusions and corresponding grooves are trapezoidal in shape, making operation simple and installation convenient, improving assembly efficiency, and avoiding the uneven torque caused by screw fastening. The cross slider 5 provided in this application has a dual-function design: [The text abruptly ends here, so the translation stops here as well.] Since the cross sections of the first protrusion 51 and the first groove 101 are both trapezoidal with a narrower root and are compatible, and the cross sections of the second protrusion 52 and the second groove 401 are also trapezoidal with a narrower root and are compatible, the cross slider 5 can be prevented from moving axially without additional fasteners. This not only prevents the flexure 4 and the cross bearing from separating axially, adapting to the high-speed operation scenario of the harmonic reducer, but also, since all the protrusions and corresponding grooves have trapezoidal inclined surfaces, the position of the flexure 4 can be automatically fine-tuned during assembly through the trapezoidal inclined surfaces, achieving automatic centering and concentricity adjustment to meet the concentricity requirements of the harmonic reducer transmission. This solves the problem in the existing cup-shaped harmonic reducer where the flexure 4 and the inner ring 1 of the cross bearing are connected by screws, resulting in cumbersome installation and difficulty in concentricity adjustment.

[0030] It should be noted that the specific connection method between the inner ring 1 and the outer ring 2 of the cross bearing is existing technology and will not be described in detail here.

[0031] In terms of some adaptive design aspects, in order to adapt to the assembly environment of the harmonic reducer, the connecting plate 53 is undoubtedly annular and allows the shaft to pass through. The first groove 101 is connected to the shaft hole of the inner ring 1 of the bearing, and the second groove 401 is connected to the shaft hole of the flexible wheel 4.

[0032] Preferably, the connecting disc 53, the first protrusion 51, and the second protrusion 52 are integrally formed. In addition, it is preferred that the angle between the length direction of the first protrusion 51 and the length direction of the second protrusion 52 is a right angle, that is, in a cross shape.

[0033] In some preferred embodiments, the mating clearance between the first protrusion 51 and the first groove 101, and the mating clearance between the second protrusion 52 and the second groove 401 are both δ, 0.015mm≤δ≤0.035mm.

[0034] This configuration, after testing and verification, ensures that the minimal clearance δ compensates for assembly deviations while preventing radial movement caused by excessive clearance. In addition, it helps ensure the compatibility of the cross slider 5 with the bearing inner ring 1 and the flexible wheel 4, and also facilitates the low-vibration and high-precision operation of the harmonic reducer.

[0035] In some preferred embodiments, the cross section of the first protrusion 51 and the second protrusion 52 is isosceles trapezoid with a base angle of a, where 76°≤a≤80°. With such arrangement, it has been tested and verified that the assembly compatibility between the cross roller 5 and the bearing inner ring 1 and the flexspline 4 is guaranteed, and meanwhile, the harmonic reducer is facilitated to run with low vibration and high precision. Exemplarily, a is 78°.

[0036] In some preferred embodiments, the cross section of the first protrusion 51 and the second protrusion 52 is isosceles trapezoid with a base angle of a, the cross section of the first groove 101 and the second groove 401 is isosceles trapezoid with a base angle of a', a' and a match, and the matching tolerance of a' and a is ±0.5°. With such arrangement, it has been tested and verified that the assembly compatibility between the cross roller 5 and the bearing inner ring 1 and the flexspline 4 is guaranteed, and meanwhile, the harmonic reducer is facilitated to run with low vibration and high precision. In particular, when combined with the foregoing embodiments, the harmonic reducer has better performance of running with low vibration and high precision.

[0037] In some preferred embodiments, the height of the first protrusion 51 and the second protrusion 52 protruding relative to the connecting disc 53 is H, and 1.3mm≤H≤2mm. The height of the protrusion is the dimension in the axial direction. With such arrangement, the first protrusion 51 and the second protrusion 52 are dimensionally constrained, and it has been tested and verified that the harmonic reducer is facilitated to run with low vibration and high precision. In particular, when combined with the foregoing embodiments, the harmonic reducer has better performance of running with low vibration and high precision.

[0038] In some preferred embodiments, the diameter of the connecting disc 53 is D, the span of the pair of first protrusions 51 in the radial direction of the connecting disc 53, the span of the pair of second protrusions 52 in the radial direction of the connecting disc 53 are L, and 0.68×D≤L≤0.72×D. With such arrangement, the first protrusion 51 and the second protrusion 52 are dimensionally constrained, and it has been tested and verified that the harmonic reducer is facilitated to run with low vibration and high precision. In particular, when combined with the foregoing embodiments, the harmonic reducer has better performance of running with low vibration and high precision. Exemplarily, L is 0.70×D.

[0039] In some preferred embodiments, the first protrusion 51 and the second protrusion 52 each have a height of H protruding relative to the connecting disc 53; the first protrusion 51 and the second protrusion 52 each have an isosceles trapezoidal cross section, the upper base of the cross section of the first protrusion 51 and the second protrusion 52 has a width of b1, the lower base of the cross section of the first protrusion 51 and the second protrusion 52 has a width of b2, 0.8xH≤b1≤0.9xH, 0.8mm≤b2-b1≤1.2mm; the first groove 101 and the second groove 401 each have a depth of h in the harmonic reducer axial direction, 0.03mm≤h-H≤0.05mm; the groove bottom of the first groove 101 and the second groove 401 has a width of b3, b3=b2+2xδ, 0.015mm≤δ≤0.035mm, that is, the groove bottom of the first groove 101 is designed to satisfy the existence of the fitting gap δ with the first protrusion 51, and the groove bottom of the second groove 401 is designed to satisfy the existence of the fitting gap δ with the second protrusion 52. In this way, the first protrusion 51 and the second protrusion 52 are subjected to size constraints, and the first protrusion 51 and the second protrusion 52 and the corresponding first groove 101 and second groove 401 are subjected to size fitting constraints in the axial direction, which is beneficial to the low-vibration and high-precision operation of the harmonic reducer through tests and verification. In particular, when combined with the foregoing embodiments, the harmonic reducer has more optimal low-vibration and high-precision operation performance.

[0040] In some preferred embodiments, the end portion of the first protrusion 51 and the second protrusion 52 located on the radially outer side each has a rounded corner structure with a radius of r, 0.2mm≤r≤0.4mm.

[0041] In some preferred embodiments, the surface average roughness of the first protrusion 51 and the second protrusion 52 is less than or equal to 0.4μm.

[0042] In some preferred embodiments, the surface average roughness of the first groove 101 and the second groove 401 is less than or equal to 0.4μm.

[0043] In this way, the first protrusion 51 and the second protrusion 52, the first groove 101 and the second groove 401 are subjected to surface precision constraints, which is beneficial to the low-vibration and high-precision operation of the harmonic reducer through tests and verification. In particular, when combined with the foregoing embodiments, the harmonic reducer has more optimal low-vibration and high-precision operation performance.

[0044] In some preferred embodiments, the cup bottom of the flexspline 4 has a connecting boss 41, the second groove 401 is formed in the connecting boss 41, the connecting disc 53 is in diameter adaptation with the connecting boss 41 and has a diameter tolerance of H7; the end face roundness runout tolerance of the connecting disc 53 is less than or equal to 0.003mm.

[0045] In some optional embodiments, the top of the first protrusion 51 and the top of the second protrusion 52 are configured to have elasticity. It can also be said that the top of the first protrusion 51 and the top of the second protrusion 52 are provided with an elastic structure. The top of the first protrusion 51 and the top of the second protrusion 52 are located on the side of the first protrusion 51 and the second protrusion 52 away from the connecting plate 53, which is the side where the lower base of the trapezoidal cross section of the first protrusion 51 and the second protrusion 52 is located. In this way, during installation, the interaction between the first protrusion 51 and the first groove 101, the second protrusion 52 and the second groove 401, through the characteristics of the trapezoidal slope matching, and the elastic structure of the top of the first protrusion 51 and the top of the second protrusion 52, is more conducive to fine tuning of the cross roller 5 during installation, automatic adjustment of the concentricity of the flexspline 4 and the bearing inner ring 1, without the need for additional adjustment tools.

[0046] Further, as to how the top of the first protrusion 51 and the top of the second protrusion 52 are configured to have elasticity, exemplarily, at least the top of the first protrusion 51 and the top of the second protrusion 52 are provided with a plating layer, specifically a nickel layer or a molybdenum disulfide layer, etc. additional layer with elastic buffer characteristics, such plating layer also has the effect of reducing noise and vibration, and also has high wear resistance and high hardness; moreover, the first protrusion 51 and the second protrusion 52 are protruding structures, and such design has the advantage of facilitating control of material and plating treatment.

[0047] In some optional embodiments, the bottom of the first groove 101 and the bottom of the second groove 401 are configured to have elasticity. It can also be said that the bottom of the first groove 101 and the bottom of the second groove 401 are provided with an elastic structure. In this way, during installation, the interaction between the first protrusion 51 and the first groove 101, the second protrusion 52 and the second groove 401, through the characteristics of the trapezoidal slope matching, and the elastic structure of the bottom of the first groove 101 and the bottom of the second groove 401, is more conducive to fine tuning of the cross roller 5 during installation, automatic adjustment of the concentricity of the flexspline 4 and the bearing inner ring 1, without the need for additional adjustment tools.

[0048] Further, as to how the bottom of the first groove 101 and the bottom of the second groove 401 are configured to have elasticity, exemplarily, based on the body of the bearing inner ring 1, the bottom of the first groove 101 has a plating molybdenum disulfide layer, which can exhibit recoverable elasticity; the cup bottom of the flexspline 4 can be designed to be made of PEEK (Polyetheretherketone), PPS (Polyphenylene sulfide), PPA (Polyphthalamide), etc. high-performance engineering plastic injection molding, and due to the material characteristics, the bottom of the second groove 401 has a certain elasticity.

[0049] In summary, the present application takes the concentricity of the flexible gear 4 and the bearing inner ring 1 of the cross bearing as the core target, and through the three principles of "narrowing the gap, precise size correlation, and strict control of shape and position tolerance", the size of the first protrusion 51 and the second protrusion 52 of the cross slider 5 and the first groove 101 of the bearing inner ring 1 and the second groove 401 of the flexible gear 4 is constrained. Specifically, on the one hand, the assembly deviation is compensated by the extremely small fitting gap δ, while avoiding the radial runout caused by the excessively large gap; on the other hand, the size correlation of the first protrusion 51, the second protrusion 52 and the connecting disc 53 ensures balanced torque transmission and reduces vibration caused by stress concentration; the high-precision surface and the shape and position tolerance are matched to reduce friction vibration and noise.

[0050] The harmonic reducer obtained by combining the foregoing embodiments has at least the following effects: first, it is easy to install, because the screw fastening connection is cancelled, and during assembly, only the corresponding protrusion and groove need to be slid and engaged, which is simple to operate and improves assembly efficiency; second, it can automatically adjust the concentricity, and through the trapezoidal cross-section design of the protrusion and the groove, automatic concentric adjustment of the flexible gear 4 and the bearing inner ring 1 is achieved, improving the transmission accuracy of the harmonic reducer; third, it can prevent the cross slider 5 from being separated from the flexible gear 4 and the cross bearing in the axial direction, due to the design that the root of the protrusion is narrower than the other side; fourth, it reduces noise and vibration, through the precise fit between the protrusion of the cross slider 5 and the groove of the cup bottom of the flexible gear 4 and the groove of the bearing inner ring 1, as well as the automatic centering function brought by the trapezoidal cross-section design, the vibration caused by assembly deviation and running eccentricity is greatly weakened, the noise is reduced from the root, and the harmonic reducer is realized to run quietly with low vibration; fifth, it prolongs the service life, through reasonable size design and material selection, the wear resistance and fatigue resistance between the protrusion of the cross slider 5 and the groove of the cup bottom of the flexible gear 4 and the groove of the bearing inner ring 1 are improved, prolonging the service life of the harmonic reducer.

[0051] Based on the above harmonic reducer, the present application further provides a robot, which comprises the above harmonic reducer. Since the robot has the above harmonic reducer, the beneficial effects of the robot brought by the harmonic reducer are described above, and will not be repeated here.

[0052] The basic principles of the present application are described above in conjunction with specific embodiments, but it should be pointed out that the advantages, advantages, effects and the like mentioned in the present application are only examples and not limitations, and these advantages, advantages, effects and the like cannot be considered as the must-have of each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of example and for the purpose of understanding, and not for limitation, and the above details do not limit the present application to the above specific details.

[0053] The block diagrams of the devices, apparatuses, equipment, systems involved in the present application are only illustrative examples and are not intended to require or imply that the connection, arrangement, configuration must be as shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, systems can be connected, arranged, configured in any manner. Words such as "include", "contain", "have", and the like are open-ended words, mean "including but not limited to", and can be used interchangeably. The words "or" and "and" used herein mean the word "and / or", and can be used interchangeably, unless the context clearly indicates otherwise. The word "such as" used herein means the phrase "such as but not limited to", and can be used interchangeably.

[0054] It should also be noted that in the devices, apparatuses and methods of the present application, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be considered as equivalent solutions of the present application.

[0055] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other aspects without departing from the scope of the present application. Thus, the present application is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0056] It should be understood that the adjectives "first", "second", "third", "fourth", "fifth" and "sixth" used in the embodiments of the present application are only used for more clearly describing the technical solutions, and cannot be used to limit the protection scope of the present application.

[0057] The above description has been given for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A harmonic reducer, characterized in that, include: A cross bearing includes an inner ring (1) and an outer ring (2), wherein the end face of the inner ring (1) is provided with a first groove (101) extending radially, and the first groove (101) is provided with a pair of radially opposite grooves; The rigid wheel (3) is fastened to the outer ring (2) of the bearing; The flexible wheel (4) is fitted inside the rigid wheel (3), and the outer teeth of the flexible wheel (4) mesh with the inner teeth of the rigid wheel (3). The flexible wheel (4) is a cup-shaped flexible wheel and the bottom of the cup is provided with a second groove (401) extending radially, and the second groove (401) is provided with a pair of radially opposite grooves. The cross slider (5) includes a connecting plate (53), a first protrusion (51), and a second protrusion (52). The first protrusion (51) is located on the first end face of the connecting plate (53). The first protrusion (51) extends radially and has a pair of radially opposite protrusions. The second protrusion (52) is located on the second end face of the connecting plate (53). The second protrusion (52) extends radially and has a pair of radially opposite protrusions. There is an angle between the length direction of the first protrusion (51) and the length direction of the second protrusion (52). The first protrusion (51) engages with the first groove (101), and the second protrusion (52) engages with the second groove (401) so that the flexible wheel (4) and the bearing inner ring (1) are assembled and connected by the cross slider (5). Wave generator, inner sleeve of the flexure (4); The first protrusion (51) and the second protrusion (52) have trapezoidal cross sections and the side connected to the connecting plate (53) is a trapezoidal upper base. The first groove (101) is adapted to the shape of the first protrusion (51) and the second groove (401) is adapted to the shape of the second protrusion (52).

2. The harmonic reducer according to claim 1, characterized in that, The fitting gap between the first protrusion (51) and the first groove (101) and the fitting gap between the second protrusion (52) and the second groove (401) are both δ, 0.015mm≤δ≤0.035mm.

3. The harmonic reducer according to claim 1, characterized in that, The cross-sections of the first protrusion (51) and the second protrusion (52) are both isosceles trapezoids with a base angle of α, wherein: 76°≤α≤80°; and / or, The cross-sections of the first groove (101) and the second groove (401) are both isosceles trapezoids with a base angle of α´, and the fit tolerance between α´ and α is ±0.5°.

4. The harmonic reducer according to claim 1, characterized in that, The height of the first protrusion (51) and the second protrusion (52) relative to the connecting disk (53) is H, where 1.3mm≤H≤2mm.

5. The harmonic reducer according to claim 1, characterized in that, The diameter of the connecting disk (53) is D, the span of the pair of first protrusions (51) in the radial direction of the connecting disk (53) and the span of the pair of second protrusions (52) in the radial direction of the connecting disk (53) are both L, 0.68×D≤L≤0.72×D.

6. The harmonic reducer according to claim 1, characterized in that, The first protrusion (51) and the second protrusion (52) protrude at a height of H relative to the connecting disk (53); The cross-sections of the first protrusion (51) and the second protrusion (52) are both isosceles trapezoids. The width of the upper base of the cross-sections of the first protrusion (51) and the second protrusion (52) is b1, and the width of the lower base of the cross-sections of the first protrusion (51) and the second protrusion (52) is b2. 0.8×H≤b1≤0.9×H, 0.8mm≤b2-b1≤1.2mm; The depth of the first groove (101) and the second groove (401) in the axial direction of the harmonic reducer is h, where 0.03mm≤hH≤0.05mm; The bottom width of the first groove (101) and the second groove (401) is b3, b3=b2+2×δ, 0.015mm≤δ≤0.035mm.

7. The harmonic reducer according to claim 1, characterized in that, The ends of the first protrusion (51) and the second protrusion (52) located on the radially outer side both have rounded corners and a radius of r, 0.2mm≤r≤0.4mm.

8. The harmonic reducer according to claim 1, characterized in that, The average surface roughness of the first bump (51) and the second bump (52) is less than or equal to 0.4 μm; and / or, The average surface roughness of the first groove (101) and the second groove (401) is less than or equal to 0.4 μm.

9. The harmonic reducer according to claim 1, characterized in that, The bottom of the flexible wheel (4) has a connecting boss (41), the second groove (401) is formed on the connecting boss (41), and the diameter of the connecting plate (53) is adapted to the diameter of the connecting boss (41) and the diameter tolerance is H7. The end face runout tolerance of the connecting plate (53) is less than or equal to 0.003 mm.

10. The harmonic reducer according to claim 1, characterized in that, The tops of the first protrusion (51) and the second protrusion (52) are configured to be elastic; or, The bottom of the first groove (101) and the bottom of the second groove (401) are configured to be elastic.

11. A robot, characterized in that, Including the harmonic reducer as described in any one of claims 1-10.

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