Cup-shaped harmonic flexible gear with high bearing capacity

Abstract

The high-bearing-capacity cup-shaped harmonic flexible gear is composed of a cup bottom and a cup cylinder, an output connecting flange is arranged in the middle of the cup bottom, the edge of the output connecting flange is connected with the bottom of the cup cylinder through a semicircular arc to form a semicircular cup bottom, and flexible gear teeth are arranged on the periphery of the top end of the cup cylinder. The gear teeth of the flexible gear are subjected to radial modification and tooth-direction modification at the same time, and the modified gear teeth are in an arc shape with the high middle and the two low ends in the axial direction and the tangential direction. Due to the fact that the structure of the cup bottom of the cup-shaped harmonic flexible gear in the prior art is changed, the stress condition of the cup bottom of the cup-shaped harmonic flexible gear is fundamentally changed, and the bearing capacity of the cup bottom of the cup-shaped harmonic flexible gear is improved; besides, due to the fact that the gear teeth of the cup-shaped harmonic flexible gear in the prior art are subjected to proper radial modification and tooth-direction modification at the same time, the bearing capacity of the gear teeth of the cup-shaped harmonic flexible gear is improved, and the bearing capacity of the cup bottom of the cup-shaped harmonic flexible gear and the bearing capacity of the gear teeth of the cup-shaped harmonic flexible gear are improved at the same time.

Description

Technical Field

[0001] The invention relates to a cup-shaped harmonic flex spline, in particular to a cup-shaped harmonic flex spline with high load-bearing capacity, and belongs to the technical field of harmonic gear transmission. Background Art

[0002] The harmonic gear transmission is usually composed of three basic components: a flexible wheel, a rigid wheel and a wave generator. The transmission of its motion or power is achieved under the action of the wave generator, which forces the flexible wheel to continuously produce elastic deformation and interact with the rigid wheel to achieve the purpose of transmission. In the harmonic gear transmission, the harmonic flexible wheel is the most core and key component, and it is also the component with the lowest strength. This is because the harmonic flexible wheel works under the state of repeated elastic deformation, and is affected by the bending stress caused by the deformation of the wave generator and the bending moment of the gear meshing force during the working process.

[0003] The cup-type harmonic flexwheel is currently the most commonly used structural form in harmonic reducers. However, in the prior art, the cup-type harmonic flexwheel often has two failure modes during use: cup bottom breakage and gear tooth wear. The reason for the cup bottom breakage is that the cup bottom shape of the cup-type harmonic flexwheel in the prior art is a flat bottom structure, the inner side of the cup bottom output connecting flange is flush with the thin-walled cup bottom, and the outer side protrudes toward the cup bottom. During use, the stress at the turning point between the cup bottom and the cup body is the greatest. When the stress exceeds the allowable value, the cup bottom breakage will occur. The reason for the gear tooth wear failure is that the flexwheel teeth are simultaneously affected by the bending stress caused by the deformation of the wave generator and the gear meshing force bending moment during use. The harmonic flexwheel undergoes axial bending and torsional deformation at the same time, causing the part of the gear teeth that originally participated in the meshing to interfere with or fail to mesh with the rigid wheel teeth in the axial direction and tangential direction. The number and meshing area of ​​the meshing teeth of the flexwheel and the rigid wheel are sharply reduced, and the stress of the flexwheel increases sharply, which eventually causes the gear tooth wear failure.

[0004] The above situation shows that the cup-type harmonic flexible wheel in the prior art still has the problem of small bearing capacity and needs to be further improved. Summary of the invention

[0005] The purpose of the present invention is to provide a cup-shaped harmonic flex spline with high load-bearing capacity, which has higher load-bearing capacity and service life under the condition that the gear parameters, cup diameter, axial size and volume are exactly the same, thereby overcoming the shortcomings of the prior art.

[0006] The technical solution of the present invention is: a high-load-bearing cup-shaped harmonic flexspline, which consists of a cup bottom and a cup barrel. The middle of the cup bottom is an output connecting flange, and the edge of the output connecting flange is connected to the bottom of the cup barrel through a "semicircular" arc to form a "semicircular" cup bottom. Flexspline teeth are arranged on the outer periphery of the top of the cup barrel. The flexspline teeth are simultaneously subjected to radial shaping and tooth shaping. After shaping, the teeth present an arc shape with a high middle and low ends in both the axial and tangential directions.

[0007] In the aforementioned high-load-bearing cup-type harmonic flexible wheel, the "semi-circular" cup bottom protrudes outward from the cup and is substantially flush with the outer side of the output connection flange.

[0008] In the aforementioned high-load-bearing cup-type harmonic flexspline, the arc radius r of the "semicircular" cup bottom and the flexspline tooth width B have a relationship of r=(0.38-0.46)B.

[0009] In the aforementioned high-load-bearing cup-shaped harmonic flexspline, the pitch line of the flexspline teeth after radial modification is an arc with a high middle and low ends.

[0010] In the aforementioned high-load-bearing cup-shaped harmonic flexspline, the pitch line arc radius of the flexspline teeth is R=(3.14-4.26)D 2 / L, the distance from the center of the pitch circle arc of the flexspline tooth to the end face of the tooth b = (0.45-0.56) BL / D; where: D is the inner hole diameter of the flexspline, L is the length of the flexspline cylinder, and B is the width of the flexspline tooth.

[0011] In the aforementioned high-load-bearing cup-shaped harmonic flexspline, the flexspline teeth after tooth profile modification have two sides of the tooth profile that are arcs with a high middle and low ends.

[0012] In the aforementioned high-load-bearing cup-shaped harmonic flexspline, the tooth arc radius R0 of the flexspline teeth is (1.24-1.97)D 2 / L, the distance from the center of the tooth arc to the end face of the gear tooth b0 = (0.45 ~ 0.56) BL / D; where: D is the inner hole diameter of the flexspline, L is the length of the flexspline cylinder, and B is the width of the flexspline teeth.

[0013] Beneficial effects of the present invention: Due to the adoption of the above technical solution, the present invention has significant improvements over the prior art in that:

[0014] 1. Since the present invention changes the cup bottom structure of the cup-type harmonic flexspline, the flat bottom structure of the cup-type harmonic flexspline in the prior art is designed into a "semi-circular" cup bottom structure formed by connecting the cup bottom and the cup cylinder through a "semi-circular" arc. The "semi-circular" cup bottom protrudes outward from the cup and is basically flush with the outer side of the output connection flange. The arc radius r of the "semi-circular" cup bottom and the flexspline tooth width B have a relationship of r=(0.38-0.46)B. This structural change has fundamentally changed the stress condition of the cup bottom of the cup-type harmonic flexspline, greatly improving the maximum stress that can be borne at the turning point between the cup bottom and the cup body. According to the flexible gear thin shell theory and finite element simulation analysis and experiments, it is shown that when the gear parameters, cup diameter, axial size and volume are exactly the same, the load-bearing capacity of the cup bottom of the cup-type harmonic flexspline will be increased by 62-80% or even higher on the original basis.

[0015] 2. Since the present invention simultaneously performs appropriate radial modification and tooth modification on the teeth of the cup-type harmonic flexspline in the prior art, the modified flexspline teeth present an arc shape with a high middle and low ends in both the axial and tangential directions, and the modified tooth pitch arc radius R = (3.14 ~ 4.26) D 2 / L, the distance from the center of the pitch circle of the modified gear tooth to the end face of the gear tooth b = (0.45 ~ 0.56) BL / D, the radius of the tooth arc of the modified gear tooth R0 = (1.24 ~ 1.97) D 2 / L, the distance from the center of the arc of the modified gear tooth to the end face of the gear tooth b0 = (0.45 ~ 0.56) BL / D, where D is the inner hole diameter of the flexspline, L is the length of the flexspline cylinder, and B is the width of the flexspline tooth; this structural change, through finite element simulation analysis, shows that when the cup-type harmonic flexspline undergoes axial bending deformation and torsional deformation due to the bending stress caused by the deformation of the wave generator and the bending moment of the gear meshing force during use, the gear teeth that were originally going to have meshing interference no longer have meshing interference, and the gear teeth that were originally only partially meshing have become fully meshed, and the number of tooth pairs that the flexspline teeth and the rigid wheel teeth are even increased, thereby fundamentally improving the bearing capacity of the cup-type harmonic flexspline tooth portion.

[0016] In summary, since the present invention changes the structure of the cup bottom of the cup-type harmonic flexible wheel in the prior art, the stress condition of the cup bottom of the cup-type harmonic flexible wheel has undergone a fundamental change, and the bearing capacity of the cup bottom of the cup-type harmonic flexible wheel has been improved; in addition, since the present invention simultaneously performs appropriate radial modification and tooth modification on the gear teeth of the cup-type harmonic flexible wheel in the prior art, the bearing capacity of the tooth portion of the cup-type harmonic flexible wheel is improved, so that the present invention simultaneously improves the bearing capacity of the cup bottom of the cup-type harmonic flexible wheel and the bearing capacity of the tooth portion of the cup-type harmonic flexible wheel, therefore, the cup-type harmonic flexible wheel of the present invention has a greater bearing capacity and a longer service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the present invention;

[0018] Figure 2 It is a schematic diagram of the gear radial modification structure of the present invention;

[0019] Figure 3 It is a schematic diagram of the gear tooth profile modification structure of the present invention.

[0020] The marks in the attached figure are: 1-flexible wheel teeth, 2-"semi-circular" cup bottom, 3-output connecting flange, B-flexible wheel tooth width, D-flexible wheel inner hole diameter, L-flexible wheel cylinder length, R-modified wheel tooth pitch line arc radius, b-modified wheel tooth pitch line arc center to the tooth end face distance, R0-modified wheel tooth tooth arc radius, b0-modified wheel tooth tooth arc center to the tooth end face distance. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0022] An embodiment of the present invention: A high-load-bearing cup-type harmonic flexible wheel, consisting of a cup bottom and a cup barrel, with an output connecting flange 3 in the middle of the cup bottom. Two improvements are made on the basis of the cup-type harmonic flexible wheel in the prior art. First, the cup bottom structure of the existing cup-type harmonic flexible wheel is changed, and the flat bottom structure of the cup-type harmonic flexible wheel in the prior art is designed to be a "semi-circular" cup bottom 2 structure formed by connecting the cup bottom and the cup barrel through a "semi-circular" arc; second, the flexible wheel teeth 1 of the cup-type harmonic flexible wheel in the prior art are appropriately radially modified and tooth-shaped modified at the same time, and the modified flexible wheel teeth 1 present an arc shape with a high middle and low ends in both the axial and tangential directions.

[0023] The "semicircular" cup bottom 2 protrudes outward from the cup and is substantially flush with the outer side of the output connecting flange 3 .

[0024] The arc radius r of the "semicircular" cup bottom 2 and the width B of the flex spline tooth 1 have a relationship of r=(0.38-0.46)B.

[0025] After the flexspline tooth 1 is properly radially modified, its pitch line is no longer a straight line parallel to the rotation center of the flexspline, but an arc with a high middle and low ends.

[0026] Pitch arc radius of flex spline tooth 1 R = (3.14 ~ 4.26) D 2 / L, the distance from the center of the pitch circle arc of the flexspline tooth 1 to the end face of the tooth b = (0.45-0.56) BL / D; wherein: D is the inner diameter of the flexspline, L is the length of the flexspline cylinder, and B is the width of the flexspline tooth 1.

[0027] After the flex spline teeth 1 are properly modified in tooth profile, the two sides of the tooth profile of the flex spline teeth 1 are no longer straight lines, but are also arcs with a high middle and low ends.

[0028] After the flex spline tooth 1 is properly modified, the radius of the tooth arc of the flex spline tooth 1 after modification is R0 = (1.24 ~ 1.97) D 2 / L, the distance from the center of the tooth arc of the flexspline tooth 1 after modification to the tooth end face b0 = (0.45-0.56) BL / D; wherein: D is the inner hole diameter of the flexspline, L is the length of the flexspline cylinder, and B is the width of the flexspline tooth.

[0029] The present invention improves the structure of the cup-type harmonic flexible wheel and limits the size relationship between the various parts, so that the cup-type harmonic flexible wheel of the invention has a higher load-bearing capacity and service life when the gear parameters, cup diameter, axial size and volume are exactly the same.

Claims

1. A high-load-bearing cup-shaped harmonic flexure, consisting of a cup bottom and a cup barrel, characterized in that: The middle of the cup bottom is an output connection flange (3), the edge of the output connection flange (3) is connected to the bottom of the cup barrel through a "semicircular" arc to form a "semicircular" cup bottom (2), and the outer periphery of the top of the cup barrel is provided with a flexible wheel tooth (1), and the flexible wheel tooth (1) is simultaneously subjected to radial shaping and tooth direction shaping, and the modified wheel tooth presents an arc shape with a high middle and low ends in both the axial and tangential directions.

2. The high-load-bearing cup-shaped harmonic flexible wheel according to claim 1, characterized in that: The "semicircular" cup bottom (2) protrudes outward from the cup and is substantially flush with the outer side of the output connection flange (3).

3. The high-load-bearing cup-shaped harmonic flexible wheel according to claim 1, characterized in that: The arc radius r of the "semicircular" cup bottom (2) and the width B of the flexible wheel tooth (1) have a relationship of r=(0.38-0.46)B.

4. The high-load-bearing cup-shaped harmonic flexible wheel according to claim 1, characterized in that: The pitch line of the radially modified flexible wheel tooth (1) is an arc with a high middle and low ends.

5. The high-load-bearing cup-shaped harmonic flexible wheel according to claim 4, characterized in that: The pitch line arc radius of the flex spline tooth (1) is R=(3.14-4.26)D 2 / L, the distance from the center of the pitch circle arc of the flexspline tooth (1) to the tooth end face b = (0.45-0.56) BL / D; wherein: D is the diameter of the flexspline inner hole, L is the length of the flexspline cylinder, and B is the width of the flexspline tooth (1).

6. The high-load-bearing cup-shaped harmonic flexible wheel according to claim 1, characterized in that: After the tooth profile modification, the flexible wheel teeth (1) have two sides of the tooth profile that are a section of circular arc with a high middle and low ends.

7. The high-load-bearing cup-shaped harmonic flexible wheel according to claim 6, characterized in that: The tooth arc radius R0 of the flex spline teeth (1) is (1.24-1.97)D 2 / L, the distance from the center of the tooth arc to the end face of the gear tooth b0 = (0.45-0.56) BL / D; wherein: D is the inner diameter of the flexible wheel, L is the length of the flexible wheel cylinder, and B is the width of the flexible wheel tooth (1).

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