Flexible gear with reinforced edge

Abstract

The edge-strengthened flexible gear comprises a cylinder, the cylinder comprises an upper edge strengthening section, a middle gear ring section and a lower smooth cylinder section, the inner diameter of the edge strengthening section is gradually reduced towards the middle gear ring section, the minimum inner diameter of the edge strengthening section is larger than the inner diameter of the middle gear ring section, and the edge strengthening section is not in contact with a wave generator; the edge strengthening section, the gear ring section and the cylinder section cooperatively generate periodic deformation, the generation or expansion risk of fatigue cracks on the edge of the flexible gear is reduced, and the edge strengthening section can guide stress to be distributed along a wider area instead of being concentrated on a certain specific point. By means of the stress dispersion effect, the risk of fatigue crack generation is remarkably reduced, and the fatigue resistance of the flexible gear is improved. Due to the gradual change characteristic of the edge strengthening section, stress can be gradually absorbed and dispersed in the deformation process, and therefore stress peak values are reduced. This helps to reduce the risk of fatigue crack generation.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of harmonic reducer flexspheres, and particularly relates to an edge-reinforced flexsphere. BACKGROUND

[0002] In the operation mechanism of the harmonic reducer, the flexsphere plays a crucial role, but it also faces severe challenges. The wave generator periodically extrudes the inner wall of the flexsphere, which not only causes the generation of bending stress and shear stress, but also leads to the uneven distribution of these stresses inside the flexsphere. In particular, the upper edge of the flexsphere, which is the area directly in contact with the wave generator, bears significant extrusion and stretching, becoming a high-risk area of stress concentration.

[0003] Over time, the continuous effect of this alternating stress induces fatigue cracks in the stress concentration area of the upper edge of the flexsphere. These cracks often start from the root of the tooth or the discontinuous point of the material, and then spread along a direction parallel to the axis of the flexsphere. Once the cracks start to expand, they gradually invade the smooth barrel area of the flexsphere, eventually causing the flexsphere to break. By carefully observing the flexsphere samples that have fatigue fractured, we can clearly see the path of the cracks starting from the upper edge of the flexsphere and extending to the smooth barrel area. Given the severity of fatigue fracture of the upper edge of the flexsphere, it is necessary to improve and enhance the existing technology to reduce the risk of fatigue fracture of the flexsphere, thereby prolonging the service life of the harmonic reducer and improving its reliability. CONTENT OF THE UTILITY MODEL

[0004] The utility model provides an edge-reinforced flexsphere that enhances the overall strength and durability of the flexsphere through edge structure reinforcement, thereby effectively alleviating the problem of fatigue fracture caused by periodic elastic deformation.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical solutions:

[0006] An edge-reinforced flexsphere includes a barrel, which includes an upper edge-reinforced segment, a middle gear ring segment, and a lower smooth barrel segment. The inner diameter of the edge-reinforced segment gradually decreases towards the middle gear ring segment, and its minimum inner diameter is greater than the inner diameter of the middle gear ring segment. The edge-reinforced segment does not come into contact with the wave generator. The edge-reinforced segment, the gear ring segment, and the barrel segment cooperatively undergo periodic deformation, reducing the risk of fatigue crack generation or expansion at the edge of the flexsphere.

[0007] The edge-strengthened flexspline of the present application is designed with a gradually decreasing inner diameter, but the minimum inner diameter is still larger than the outer diameter of the wave generator, thus ensuring that the two do not directly contact during operation. This design avoids the additional pressure and friction caused by direct contact, reducing the possibility of stress concentration. The entire deformation force is mainly transmitted from below the edge-strengthened segment (i.e., the barrel portion), and the edge-strengthened segment in the shape of a flared mouth can guide the stress to be distributed along a wider area rather than concentrated on a specific point. This stress dispersion effect significantly reduces the risk of fatigue cracks and improves the fatigue strength of the flexspline. Due to the gradual characteristics of the edge-strengthened segment, it can gradually absorb and disperse stress during deformation, thus reducing the occurrence of stress peaks. This helps to reduce the risk of fatigue cracks.

[0008] In a preferred implementation, the middle ring segment includes a plurality of uniformly arranged tooth bodies, and the horizontal distance l between the outer edge of the edge-strengthened segment and the outer wall of the barrel is less than or equal to the height of the tooth body to avoid interference with the engagement of the tooth body and the rigid wheel.

[0009] In a preferred implementation, the outer wall of the edge-strengthened segment has an inclination angle θ with the horizontal plane, satisfying 45° ≤ θ ≤ 60°.

[0010] Within this angle range, the edge-strengthened segment can better disperse the deformation force from the lower flexspline. Due to the presence of the inclination angle, the force will be gradually dispersed to a larger area during transmission, thereby reducing the degree of stress concentration.

[0011] In a preferred implementation, the vertical height h of the outer edge of the edge-strengthened segment and the middle ring segment satisfies 0.2mm ≤ h ≤ 0.5mm.

[0012] In a preferred implementation, the tooth body has a first inclined surface near one end of the edge-strengthened segment, and the low end of the first inclined surface is connected to the edge-strengthened segment.

[0013] By introducing the first inclined surface and connecting it to the edge-strengthened segment, the bending tendency of the tooth body when subjected to thrust is effectively limited. As the bending resistance at the tooth root is improved, the risk of fatigue fracture due to stress concentration is reduced. This helps to prolong the overall life of the flexspline.

[0014] In a preferred implementation, the other end of the tooth body is provided with a second inclined surface, and the slope of the second inclined surface is smaller than that of the first inclined surface.

[0015] In a preferred implementation, the tooth body includes a mating tooth portion and an extended tooth portion, and the mating tooth portion and the extended tooth portion are connected by the second inclined surface.

[0016] In a preferred implementation, the tooth width of the extended tooth portion gradually increases from the end connected to the second inclined surface towards the other end.

[0017] Due to the gradual increase of the tooth width, the stress is no longer concentrated in a small part of the tooth body, but is more evenly distributed on the entire tooth body. This helps to reduce stress concentration and reduce the risk of tooth body damage.

[0018] In a preferred implementation, there is a circular arc transition region between the edge reinforcement section and the middle gear ring section.

[0019] In a preferred implementation, the bottom of the cylinder is also provided with a flange plate, and the flange plate and the cylinder have a fillet structure therebetween. BRIEF DESCRIPTION OF DRAWINGS

[0020] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application. The illustrative embodiments of the present application and their descriptions serve to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0021] Figure 1 A schematic structural view of one illustrative embodiment of the edge-reinforced flexible gear of the present application is shown;

[0022] Figure 2 An enlarged structural schematic view of part A of the present application is shown; Figure 1

[0023] Figure 3 A three-dimensional structural schematic view of one illustrative embodiment of the edge-reinforced flexible gear of the present application is shown;

[0024] Figure 4 A partial structural schematic view of one illustrative embodiment of the edge-reinforced flexible gear of the present application is shown;

[0025] Label explanation:

[0026] 10, edge reinforcement section; 11, gear ring section; 110, tooth body; 1101, mating tooth part; 1102, extension tooth part; 1103, first inclined surface; 1104, second inclined surface; 12, smooth cylinder section; 13, circular arc transition region; 2, flange plate; 20, fillet structure. DETAILED DESCRIPTION

[0027] In the following, only certain illustrative embodiments are described simply. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit and scope of the present application. Therefore, the drawings and descriptions are considered to be exemplary in nature rather than limiting.

[0028] ​In the description of the utility model, it is understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model. In the utility model, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact of the first and second features, or indirect contact of the first and second features through an intermediate medium.

[0029] In the utility model, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrated; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements or the interaction relationship of two elements. However, it is noted that direct connection means that the connection between the two main bodies does not form a connection relationship through an excessive structure, but is connected to form a whole only through the connecting structure. For ordinary skilled persons in the art, the specific meaning of the above terms in the utility model can be understood according to the specific situation.

[0030] In the utility model, the description of "first", "second" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features.

[0031] The utility model will be described below in conjunction with the drawings.

[0032] The specific scheme adopted is:

[0033] As shown in Figures 1-4 The utility model provides a kind of edge reinforced flexible gear, including cylinder, cylinder includes upper edge reinforced section 10, middle gear ring section 11 and lower smooth cylinder section 12, the inner diameter of edge reinforced section 10 gradually reduces towards middle gear ring section 11 and its minimum inner diameter is greater than the inner diameter of middle gear ring section 11, and there is no contact with wave generator, edge reinforced section 10 and gear ring section 11 and cylinder section cooperate and occur periodic deformation, reduce the generation or expansion risk of fatigue crack in the edge of flexible gear.

[0034] From the perspective of the operating state of the flexspline, the presence of the edge reinforcement section 10 significantly reduces the risk of fatigue cracks occurring or propagating at the edge of the flexspline. Its unique flared structure not only enhances the strength of the flexspline edge, but also improves the overall fatigue resistance. Compared to traditional straight cylinder flexspline edge structures, this design effectively extends the service life of the flexspline by dispersing stress, optimizing deformation patterns, and enhancing structural toughness.

[0035] The flared edge reinforcement section 10 design gradually reduces the inner diameter, but the minimum inner diameter is still greater than the outer diameter of the wave generator, ensuring that the two do not come into direct contact during operation. This design avoids additional pressure and friction caused by direct contact, reducing the likelihood of stress concentration. The entire deformation force is mainly transmitted from below the edge reinforcement section 10 (i.e., the barrel portion), and the flared edge reinforcement section 10 can guide the stress to be distributed along a wider area rather than concentrated on a specific point. This stress dispersion effect significantly reduces the risk of fatigue cracks and improves the fatigue resistance of the flexspline. Due to the gradual nature of the edge reinforcement section 10, it can gradually absorb and disperse stress during deformation, reducing the occurrence of stress peaks. This helps to reduce the risk of fatigue cracks.

[0036] When the flexspline deforms, the original vertical cylinder structure may experience excessive pressure at a point or area due to stress concentration, which can easily lead to fatigue cracking. However, the flared edge reinforcement section 10 is different, its design is like a "buffer zone" that can gradually absorb and disperse these deformation forces. Specifically, when deformation forces come from below the flexspline, they will first contact the starting portion of the flared edge reinforcement section 10. And it is transmitted to gradually expanding areas, so the deformation force is dispersed to a wider area. As the deformation force continues to transmit, it will gradually spread along the shape of the flared edge, rather than concentrating on a specific point. This way of dispersing stress greatly reduces the degree of stress concentration, thereby reducing the risk of fatigue cracks. In other words, the flared edge reinforcement section 10 acts like a "stress disperser" that can disperse deformation forces that might otherwise be concentrated at a point to the entire edge reinforcement section 10, thereby improving the fatigue resistance of the flexspline.

[0037] As a preferred embodiment of the present application, referring to Figure 2 , the middle ring section 11 includes a plurality of uniformly arranged tooth bodies 110, and the horizontal distance l between the outer edge of the edge reinforcement section 10 and the outer wall of the barrel is less than or equal to the height of the tooth body 110 to avoid interference with the engagement of the tooth body 110 and the rigid wheel.

[0038] The horizontal distance l between the outer edge of the edge reinforcement section 10 (the outer edge at the maximum diameter) and the outer wall of the cylinder is strictly controlled within a certain range. This distance l should be less than or equal to the height of the tooth body 110 to avoid interference when the tooth body 110 engages with the rigid wheel. Interference may cause poor engagement, increased wear and tear, increased noise, and even damage to the entire transmission system.

[0039] If the distance l exceeds the height of the tooth body 110, the upper edge reinforcement section 10 may be too long, increasing the risk of contact with the rigid wheel or other components. This unnecessary contact not only may cause interference, but also may cause additional friction and wear, reducing the efficiency and life of the system.

[0040] As a preferred embodiment of the present application, referring to Figure 2 , the outer wall of the edge reinforcement section 10 has an inclination angle θ with the horizontal plane, satisfying 45° ≤ θ ≤ 60°.

[0041] Within this angle range, the edge reinforcement section 10 can better disperse the deformation force from the lower flexible wheel. Due to the presence of the inclination angle, the force is gradually dispersed to a larger area during transmission, thereby reducing the degree of stress concentration. Moreover, an inclination angle of 45° to 60° is relatively easy to achieve in mechanical processing, without bringing too much difficulty to the manufacturing process. At the same time, the edge reinforcement section 10 within this angle range has high structural stability, making it less likely to deform or be damaged when subjected to external forces. If the inclination angle is too small (such as less than 45°), it is easy to increase the degree of stress concentration, thereby reducing the fatigue resistance. If the inclination angle is too large (such as greater than 60° and less than 90°), the edge reinforcement section 10 may not be able to effectively disperse the stress, also reducing the fatigue resistance. Setting the inclination angle θ between the outer wall of the edge reinforcement section 10 and the horizontal plane within the range of 45° to 60° can take into account the requirements of fatigue resistance, processability and structural stability, etc.

[0042] As a preferred embodiment of the present application, referring to Figure 2 , the vertical height h of the outer edge of the edge reinforcement section 10 and the middle tooth ring section 11 satisfies 0.2mm ≤ h ≤ 0.5mm.

[0043] In this height range, the edge reinforcement section 10 can provide sufficient support and reinforcement, effectively dispersing the deformation force from the lower flexspline, reducing stress concentration, and thus improving the fatigue resistance of the overall structure. The appropriate vertical height h allows the edge reinforcement section 10 to better absorb and disperse stress when subjected to external forces, avoiding the generation of fatigue cracks due to stress concentration. In this height range, the edge reinforcement section 10 can fully utilize the material properties, neither wasting material due to excess nor compromising its reinforcement effect due to insufficient material. Setting an appropriate vertical height h can also avoid interference between the edge reinforcement section 10 and the middle gear ring section 11 or other components.

[0044] As a preferred embodiment of the present application, the tooth body 110 has a first inclined surface 1103 near one end of the edge reinforcement section 10, and the first inclined surface 1103 is connected to the edge reinforcement section 10 at the low end.

[0045] The tooth body 110 is designed with a first inclined surface 1103 near one end of the edge reinforcement section 10, preventing contact interference between the tooth body 110 and the edge reinforcement section 10. In traditional straight cylindrical tooth body 110 designs, the tooth body 110 tends to bend when subjected to meshing thrust, especially at the tooth root, and this bending can cause stress concentration, increasing the risk of fatigue fracture. By introducing the first inclined surface 1103 and connecting it to the edge reinforcement section 10, the bending tendency of the tooth body 110 when subjected to thrust is effectively limited. As the bending resistance at the tooth root is improved, the risk of fatigue fracture due to stress concentration is reduced. This helps to prolong the overall life of the flexspline.

[0046] Further, referring to Figure 4 , the other end of the tooth body 110 is provided with a second inclined surface 1104, and the slope of the second inclined surface 1104 is smaller than that of the first inclined surface 1103.

[0047] As the slope of the second inclined surface 1104 is smaller, when the tooth body 110 is subjected to external forces, the stress distribution is more uniform, reducing the phenomenon of stress concentration. This helps to reduce the risk of damage to the tooth body 110 due to excessive stress. By optimizing the stress distribution, the second inclined surface 1104 can more effectively disperse external forces, thus improving the load-carrying capacity of the tooth body 110. The tooth body 110 includes a mating tooth portion 1101 and an extension tooth portion 1102, which are connected by the second inclined surface 1104.

[0048] The engagement of the matching tooth portion 1101 with the gear teeth generates a certain stress concentration. The presence of the extended tooth portion 1102, connected through the second inclined surface 1104, can effectively disperse these stresses and reduce the phenomenon of stress concentration, thereby improving the overall strength of the tooth body 110. As an additional support structure, the extended tooth portion 1102 can enhance the bending resistance of the tooth body 110 when subjected to external forces. This helps to prevent the tooth body 110 from being damaged due to excessive bending and improves the stability of the transmission system.

[0049] Further, the extended tooth portion 1102 is connected to the second inclined surface 1104, and the tooth width gradually increases from one end to the other end.

[0050] The extended tooth portion 1102 gradually increases the tooth width from one end connected to the second inclined surface 1104 to the other end. This allows the force to gradually disperse along the tooth width direction when subjected to external forces. Due to the gradual increase in tooth width, the stress is no longer concentrated in a small area of the tooth body 110, but is more evenly distributed throughout the tooth body 110. This helps to reduce the phenomenon of stress concentration and reduce the risk of damage to the tooth body 110. By dispersing the force to a wider area, the overall structural strength of the tooth body 110 is enhanced. This helps to improve the fatigue resistance of the tooth body 110, enabling it to withstand greater loads and longer service life.

[0051] As a preferred embodiment of the present application, there is a circular arc transition area 13 between the edge reinforcement section 10 and the middle tooth ring section 11. The design of the circular arc transition area 13 achieves a smooth transition between the edge reinforcement section 10 and the middle tooth ring section 11, avoiding stress concentration due to shape mutation. The circular arc transition area 13 enhances the connection strength between the edge reinforcement section 10 and the middle tooth ring section 11, enabling them to work better together and withstand external forces.

[0052] As a preferred embodiment of the present application, the bottom of the cylinder is also provided with a flange plate 2, and the flange plate 2 has a round corner structure 20 with the cylinder.

[0053] The parts not described in the present application can be realized by using or referring to the existing technology.

[0054] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any skilled person in the art can easily think of various changes or substitutions within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An edge-stiffened flexspline, characterized by, The barrel includes an upper edge reinforcement section, a middle gear ring section and a lower smooth cylinder section, the inner diameter of the edge reinforcement section gradually decreases towards the middle gear ring section and the minimum inner diameter is greater than the inner diameter of the middle gear ring section, the edge reinforcement section is in contact with the wave generator, the edge reinforcement section and the gear ring section and the cylinder section are cooperatively deformed periodically, and the generation or expansion risk of fatigue cracks at the edge of the flexible gear is reduced.

2. The edge-strengthened flexspline of claim 1, wherein, The middle gear ring section includes a plurality of uniformly arranged tooth bodies, and the horizontal distance l between the outer edge of the edge reinforcement section and the outer wall of the barrel is less than or equal to the height of the tooth body to avoid interference with the meshing of the tooth body and the rigid gear.

3. The edge-strengthened flexspline of claim 2, wherein, The outer wall of the edge reinforcement section has an inclination angle θ with the horizontal plane, and 45°≤θ≤60° is satisfied.

4. The edge-strengthened flexspline of claim 2, wherein, The vertical height h of the outer edge of the edge reinforcement section and the middle gear ring section satisfies 0.2mm≤h≤0.5mm.

5. The edge-strengthened flexspline of claim 2, wherein, The tooth body has a first inclined surface near one end of the edge reinforcement section, and the low end of the first inclined surface is connected to the edge reinforcement section.

6. The edge-strengthened flexspline of claim 2, wherein, The other end of the tooth body is provided with a second inclined surface, and the slope of the second inclined surface is smaller than that of the first inclined surface.

7. The edge-strengthened flexspline of claim 6, wherein, The tooth body includes a matching tooth part and an extension tooth part, and the matching tooth part and the extension tooth part are connected through the second inclined surface.

8. The edge-strengthened flexspline of claim 7, wherein, The tooth width of the extension tooth part gradually increases from the end connected to the second inclined surface to the other end.

9. The edge-strengthened flexspline of claim 1, wherein, There is a circular arc transition area between the edge reinforcement section and the middle gear ring section.

10. The edge-strengthened flexspline of claim 1, wherein, The bottom of the barrel is also provided with a flange plate, and the flange plate and the barrel have a round corner structure.

Images