Flexible gear structure capable of reducing assembly stress of hat-shaped flexible gear and harmonic reducer

Abstract

The invention provides a flexible gear structure capable of reducing assembly stress of a hat-shaped flexible gear and a harmonic reducer, and relates to the field of harmonic reducer structures, the flexible gear structure comprises a flexible gear base, and the flexible gear base is provided with a plurality of round-head cylindrical long-strip grooves in the radial direction of an inner hole; the connecting edge of the flexible gear ring barrel radially extends outwards to form a plurality of bosses, the bosses are arranged in the radial direction of the inner hole, and the number and the position of the bosses correspond to the number and the position of the round-head cylindrical long-strip-shaped grooves; a boss is arranged on the side wall of the flexible gear tooth ring cylinder, a flange is arranged on the boss of the flexible gear tooth ring cylinder, extends into the round-head cylindrical long-strip-shaped groove and slides in the round-head cylindrical long-strip-shaped groove, and the flexible gear is of a split combined structure. The breakthrough improvement of accurate meshing of the rigid gear and the flexible gear is achieved while the torque is effectively transmitted through floating connection of the output end. When the flexible gear is subjected to assembly deformation, the flexible gear sliding block can guide the tail end of the side wall to generate radial deformation, and compared with a traditional integrated structure, the design enables the assembly deformation stress peak value to be greatly reduced.

Description

Technical Field

[0001] The present invention relates to the field of harmonic reducer structures, and in particular to a flexible spline structure capable of reducing the assembly stress of a top-hat-shaped flexible spline and a harmonic reducer. Background Art

[0002] In the existing harmonic reducer technology, the flexible wheel has significant defects due to the uneven distribution of axial structural rigidity and the rigid fixed connection at the output end: first, the flexible wheel ring is subjected to high assembly deformation stress under the action of the wave generator and the rigid fixation at the output end forms a deformation constraint, which causes asymmetric three-dimensional warping in the ring area, destroying the meshing conjugation of the rigid and flexible wheel, and significantly reducing the transmission accuracy and life; second, the traditional solution relies on three-dimensional profiling teeth or complex tooth design to compensate for deformation distortion, but the processing technology of this type of tooth shape is complex and costly, and can only improve the local tooth surface contact state to a limited extent, and cannot systematically solve the problem of overall meshing quality deterioration. On the contrary, the increase in processing precision requirements restricts mass production efficiency. Summary of the Invention

[0003] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present invention provide a flexspline structure and a harmonic reducer that can reduce the assembly stress of a top-hat flexspline. The technical problem to be solved by the present invention is that the existing harmonic reducer suffers from three-dimensional warping and high stress concentration in the gear ring due to the uneven axial rigidity of the flexspline structure and the rigid fixed connection at the output end. The design scheme that relies on complex tooth profile compensation leads to high processing costs and limited effects, resulting in a technical dilemma in which it is difficult to achieve both transmission accuracy and production efficiency.

[0004] To achieve the above-mentioned object, the present invention provides the following technical solutions: a flexible wheel structure and a harmonic reducer capable of reducing the assembly stress of a top-hat-shaped flexible wheel, comprising a flexible wheel base, an inner hole being formed therein, and a plurality of round-headed cylindrical long grooves being formed in the radial direction of the inner hole of the flexible wheel base; a flexible wheel gear ring cylinder, wherein the connecting edge of the flexible wheel gear ring cylinder radiates outward to form a plurality of bosses, the bosses being arranged along the radial direction of the inner hole, and the number and position of the bosses and the round-headed cylindrical long grooves corresponding to each other; a flange is provided on the boss of the flexible wheel gear ring cylinder, the flange extends into the round-headed cylindrical long groove, and slides in the groove.

[0005] In a preferred embodiment, the flange is a flexible wheel slider, and a circular groove is provided on the boss of the flexible wheel gear ring cylinder. One end of the flexible wheel slider is embedded in the circular groove, and the other end can slide in the round-head cylindrical long groove.

[0006] In a preferred embodiment, the diameter of the flexspline slider is equal to the width of the round-head cylindrical long groove.

[0007] In a preferred embodiment, a recessed groove is provided on the inner periphery of the flexible wheel base, the flexible wheel base and the flexible wheel pressure ring are detachably connected, ridges are evenly distributed on the flexible wheel pressure ring, the flexible wheel pressure ring contacts the recessed groove of the flexible wheel base through the ridges, and the boss of the flexible wheel gear ring cylinder is located in the space formed by the corresponding adjacent ridges.

[0008] In a preferred embodiment, when the ridges of the flexspline pressure ring fit into the recesses of the flexspline base, the outer surfaces of the flexspline base and the flexspline pressure ring are flush.

[0009] In a preferred embodiment, screw holes are drilled through the flexspline base and the flexspline pressure ring, and screws are passed through the screw holes. The screws are used to connect the flexspline base and the flexspline pressure ring to the end cover of the harmonic generator.

[0010] In a preferred embodiment, the number of screws is 16, and each screw is located between corresponding adjacent bosses.

[0011] In a preferred embodiment, the number of the round-headed cylindrical long grooves is 16.

[0012] In a preferred embodiment, an arc-shaped bend is formed at the connecting position between the boss and the side edge of the flexspline gear ring cylinder.

[0013] A harmonic reducer capable of reducing the assembly stress of a top-hat flexspline, comprising the above-mentioned flexspline structure The technical effects and advantages of the present invention are as follows: 1. The flexspline utilizes a split, modular structure. By installing a flexspline slider assembly on the sidewall of the flexspline gear ring, this achieves a floating connection at the output end, effectively transmitting torque while also achieving a breakthrough improvement in precise meshing between the rigid and flexspline. When the flexspline deforms during assembly, the flexspline slider guides the radial deformation of the sidewall end. Compared to traditional one-piece structures, this design significantly reduces peak stress during assembly deformation. This split structure effectively avoids material fatigue caused by localized stress concentration.

[0014] 2. Compared to traditional structures that are limited to unilateral deformation, this invention achieves synchronized radial deformation of both ends of the flexspline through a slider-type floating connection at the output end. Experimental data shows that this floating connection method can control the three-dimensional warping of the ring gear to near zero, reducing the maximum deformation stress by 35-50% compared to traditional structures. This precise deformation control ensures conjugate matching between the meshing surfaces of the rigid-flex spline and improves transmission accuracy.

[0015] 3. No need to use three-dimensional tooth shape or practice tooth shape, which simplifies the production process, reduces production costs and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The disclosure of the present invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. In the accompanying drawings, the same reference numerals are used to refer to the same components. Among them: Figure 1 This is a perspective of the assembly diagram of the top-hat type flexible pulley used in the present invention.

[0017] Figure 2 This is another perspective of the assembly diagram of the top-hat type flexible pulley used in the present invention.

[0018] Figure 3 This is a cross-sectional view of the top-hat type flexible pulley used in the present invention.

[0019] Figure 4 This is a three-dimensional structural diagram of the flexible gear ring cylinder used in the present invention.

[0020] Figure 5 This is a three-dimensional structural diagram of the flexible wheel base used in the present invention.

[0021] Figure 6 This is a three-dimensional structural diagram of the flexible wheel pressure ring used in the present invention.

[0022] Figure 7 This is a three-dimensional structural diagram of the flexible wheel slider used in the present invention.

[0023] Figure 8 This is the plan assembly drawing of the top-hat type flexible disc harmonic reducer.

[0024] Figure 9 This is the stress diagram of the finite element analysis of the flexible wheel structure used in the present invention.

[0025] The accompanying drawings are marked as follows: 1. output end cover; 2. flexible wheel; 201. flexible wheel base; 202. flexible wheel slider; 203. flexible wheel gear cylinder; 204. flexible wheel pressure ring; 205. screw; 3. input shaft wave generator cam; 4. deep groove ball bearing; 5. cross bearing; 6. rigid wheel; 7. input end cover; 8. flexible bearing; DETAILED DESCRIPTION

[0026] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific embodiments and drawings are only exemplary descriptions of the technical solution of the present invention and should not be regarded as the entire invention or as a limitation or restriction of the technical solution of the present invention.

[0027] Example 1 See also Figure 1-Figure 7The traditional top-hat type flexible spline is divided into two parts at the intersection of the gear ring cylinder and the side wall. The cylinder part with the gear ring is the flexible spline gear ring cylinder 203, and the side wall part is the flexible spline base 201.

[0028] The inner periphery of the flexible wheel base 201 with an inner hole is provided with a recessed groove so that the thickness of the inner periphery is smaller than that of the outer periphery. The recessed groove is provided with a plurality of round-headed cylindrical long grooves along the radial direction of the inner hole. Preferably, the number of the round-headed cylindrical long grooves is 16.

[0029] The edge of the flexible gear ring cylinder 203 near the flexible gear base 201 is bent radially outward and extends radially to form a plurality of bosses, the number and position of the bosses and the round-head cylindrical long grooves are corresponding to each other. Preferably, the number of bosses is also 16.

[0030] A circular groove is provided at the exact center of each boss.

[0031] Take another flexspline slider 202, and insert one end of the flexspline slider 202 into the circular groove of the boss, and place the other end into the round-head cylindrical long groove, and allow it to slide in the round-head cylindrical long groove. In this way, using the flexspline slider 202 as a medium, the boss can slide along the corresponding round-head cylindrical long groove.

[0032] Preferably, the diameter of the flexspline slider 202 is equal to or slightly smaller than the width of the round-head cylindrical long adjustment slot.

[0033] In order to improve the assembly and sliding stability between the boss and the round-head cylindrical long groove, a flexible pulley pressure ring 204 is further provided. The flexible pulley pressure ring 204 covers the flexible pulley base 201 and is connected by screws 205.

[0034] The connection method is as follows: 16 screw holes are respectively opened on the flexible wheel base 201 and the flexible wheel pressure ring 204. Screws 205 are inserted into the corresponding flexible wheel base 201 and the flexible wheel pressure ring 204 and then threadedly connected to the output end cover of the harmonic reducer to fix the flexible wheel 2 between the output end cover and the cross bearing.

[0035] The flexible wheel pressure ring 204 is provided with ridges, and screw holes are provided on the corresponding ridges. During installation, the screw holes and circular grooves are arranged alternately. In this way, a space is separated between two adjacent ridges. The boss is located in this space and slides radially when subjected to force. In the axial direction, the boss is mechanically constrained by the flexible wheel base 201 and the flexible wheel pressure ring 204 and cannot move.

[0036] The above configuration allows the boss of the flexspline gear ring cylinder 203 to maintain stable radial movement while being limited.

[0037] When the wave generator rotates, the flexspline gear ring cylinder 203 undergoes periodic wave deformation. Since a plurality of flexspline sliders 202 are provided on the side wall of the flexspline gear ring cylinder 203, the flexspline sliders 202 can slide back and forth in the radial direction, so that the flexspline gear ring cylinder 203 with a cylindrical thin-walled structure basically does not undergo three-dimensional warping after assembly deformation.

[0038] Example 2 Based on the above embodiments, see Figures 1-9 .

[0039] A harmonic generator, wherein a flexible bearing 8 is mounted on the cam segment of the input shaft wave generator cam 3. The outer ring of the flexible bearing 8 mates with the integral inner hole of the flexspline 2, causing the inner hole of the flexspline 2 to produce a deformation profile identical to the cam profile. A deep groove ball bearing 4 is located on the stepped surface of the cam segment. The teeth of the flexspline 2 mesh with those of the rigid wheel 6. The input end cover 7, the rigid wheel 6, and the inner ring of the cross bearing 5 are connected to the frame via the cross bearing 5. The output end cover 1, the flexspline 2, and the outer ring of the cross bearing 5 are connected to the power output shaft via the cross bearing 5. When the input shaft wave generator cam 3 rotates, the flexspline 2 undergoes periodic wave deformation.

[0040] The present invention improves and optimizes the structural defects of the traditional top-hat type flexible pulley.

[0041] In the traditional structure, the flexible wheel gear ring exhibits obvious anisotropic deformation characteristics under the action of the wave generator: its side wall area basically remains rigid, the gear ring produces radial expansion in the long axis direction, and shrinks in the short axis direction. This differential deformation causes the flexible wheel to produce significant three-dimensional warping. This solution constructs a flexible compensation mechanism by arranging multiple groups of radially sliding boss components on the circumference of the flexible wheel side wall. This structure effectively balances the deformation distribution at both ends of the gear ring cylinder, making the radial deformation in the long axis and short axis directions close to the same, greatly reducing the three-dimensional warping of the flexible wheel while also reducing the assembly stress on the flexible wheel. For a top-hat type flexible spline with a transmission ratio of 50, the assembly deformation stress of the flexible spline can be reduced to 280-320MPa, and the maximum stress at the gear ring is about 220MPa. Figure 9 The finite element stress diagram obtained by analyzing the flexible spline structure proposed by the present invention shows a calculated maximum stress of 292 MPa. The maximum stress point is located at the fillet of the side wall, and the maximum stress at the ring gear is 205 MPa. Compared with the traditional flexible spline structure, the maximum stress is reduced by nearly 35-40%, and the maximum stress at the ring gear can be reduced by 40-50%.

[0042] In summary, the design of the present invention has the following beneficial effects: 1. The flexspline utilizes a split, modular structure. By installing a flexspline slider assembly on the sidewall of the flexspline gear ring cylinder 203, this achieves a floating connection at the output end, effectively transmitting torque while also achieving a breakthrough improvement in precise meshing between the rigid and flexspline. When the flexspline 2 undergoes assembly deformation, the flexspline slider 202 guides the radial deformation of the sidewall end. Compared to traditional one-piece structures, this design significantly reduces peak stress during assembly deformation. This split-unit structure effectively avoids material fatigue caused by localized stress concentration.

[0043] 2. Compared to traditional structures that are limited to unilateral deformation, this invention achieves synchronized radial deformation of both ends of the flexspline through a slider-type floating connection at the output end. Experimental data shows that this floating connection method can control the three-dimensional warping of the ring gear to near zero, reducing the maximum deformation stress by 35-50% compared to traditional structures. This precise deformation control ensures conjugate matching between the meshing surfaces of the rigid-flex spline and improves transmission accuracy.

[0044] 3. No need to use three-dimensional tooth shape or practice tooth shape, which simplifies the production process, reduces production costs and improves production efficiency.

[0045] Due to the adoption of the flexible spline 2 structure of the present invention, the three-dimensional warping of the flexible spline gear ring is extremely small. For example, the maximum radial deformation of the flexible spline is 0.40mm, and the warping is only 0.003mm, while the warping of the traditional flexible spline structure is 0.063mm.

[0046] The technical scope of the present invention is not limited to the contents of the above description. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical idea of ​​the present invention, and these deformations and modifications should all fall within the protection scope of the present invention.

Claims

1. A flexible pulley structure capable of reducing the assembly stress of a top-hat flexible pulley, characterized in that: include: The flexible wheel base (201) is provided with an inner hole, and the flexible wheel base (201) is provided with a plurality of round-headed cylindrical long grooves along the radial direction of the inner hole; A flexible wheel gear ring cylinder (203), wherein the connection edge of the flexible wheel gear ring cylinder (203) radiates outwards to form a plurality of bosses, the bosses are arranged along the radial direction of the inner hole, and the number and position of the bosses correspond to the round-head cylindrical long grooves one by one; A flange is provided on the boss of the flexible wheel gear ring cylinder (203), and the flange extends into the round-head cylindrical long groove and slides in the groove.

2. A flexible pulley structure capable of reducing the assembly stress of a top-hat flexible pulley according to claim 1, characterized in that: The flange is a flexible wheel slider (202), and a circular groove is provided on the boss of the flexible wheel gear ring cylinder (203). One end of the flexible wheel slider (202) is embedded in the circular groove, and the other end can slide in the round-head cylindrical long groove.

3. The flexible pulley structure capable of reducing the assembly stress of the top-hat flexible pulley according to claim 2, characterized in that: The diameter of the flexible wheel slider (202) is equal to the groove width of the round-head cylindrical long groove.

4. The flexible pulley structure capable of reducing the assembly stress of a top-hat flexible pulley according to claim 1, characterized in that: The inner periphery of the flexible wheel base (201) is provided with a sunken groove, the flexible wheel base (201) and the flexible wheel pressure ring (204) are detachably connected, and convex ridges are evenly distributed on the flexible wheel pressure ring (204). The flexible wheel pressure ring (204) contacts the sunken groove of the flexible wheel base (201) through the convex ridges, and the boss of the flexible wheel gear ring cylinder (203) is located in the space formed by the corresponding adjacent convex ridges.

5. The flexible pulley structure capable of reducing the assembly stress of a top-hat flexible pulley according to claim 4, characterized in that: When the convex ridges of the flexible wheel pressure ring (204) fit into the recessed grooves of the flexible wheel base (201), the outer surfaces of the flexible wheel base (201) and the flexible wheel pressure ring (204) are flush.

6. The flexible pulley structure capable of reducing the assembly stress of a top-hat flexible pulley according to claim 1, characterized in that: The flexspline base (201) and the flexspline pressure ring (204) are provided with screw holes, and screws (205) are passed through the screw holes. The screws (205) are used to connect the flexspline base (201) and the flexspline pressure ring (204) to the end cover of the harmonic generator.

7. The flexible pulley structure capable of reducing the assembly stress of a top-hat flexible pulley according to claim 6, characterized in that: The number of the screws (205) is 16, and each screw (205) is located between corresponding adjacent bosses.

8. The flexible pulley structure capable of reducing the assembly stress of a top-hat flexible pulley according to claim 1, characterized in that: The number of the round-head cylindrical long grooves is 16.

9. The flexible pulley structure capable of reducing the assembly stress of a top-hat flexible pulley according to claim 1, characterized in that: An arc-shaped bend is formed at the connecting position of the side of the boss and the flexible gear ring cylinder (203).

10. A harmonic reducer capable of reducing the assembly stress of a top-hat flexspline, comprising the flexspline structure according to any one of claims 1 to 9.

Images