Flexible gear of harmonic reducer

Abstract

The harmonic reducer flexible gear comprises a cylinder, a gear ring is arranged on the periphery of the cylinder, the gear ring is composed of a plurality of evenly-distributed gear bodies, the top faces of the gear bodies are planes, the two ends of each gear body are provided with a first inclined face and a second inclined face respectively, the first inclined faces are close to the top end of the cylinder, and the gradient of the first inclined faces is larger than that of the second inclined faces; due to the design of the arc groove, the tooth body can be divided into two parts with the groove as the center for relative deformation when being stressed, stress possibly concentrated on the tooth root portion originally can be dispersed to a larger area, and therefore the stress concentration degree is reduced. When the flexible gear generates radial deformation under the action of the wave generator, the arc groove allows the tooth body to adapt to the deformation more flexibly. When the tooth body without the groove deforms, higher stress concentration and faster fatigue damage are possibly caused due to the fact that the middle part cannot effectively release stress.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of harmonic reducer, and particularly relates to a harmonic reducer flexspline. BACKGROUND

[0002] The harmonic gear reducer is mainly composed of a wave generator, a flexspline and a steel wheel. The reducer realizes transmission by forcing the flexspline to produce periodic elastic deformation through the wave generator (usually composed of a cam and a flexible bearing). This unique transmission mode makes the harmonic gear reducer have many remarkable advantages, such as high-precision transmission, large transmission ratio, small volume, light weight, compact structure, high carrying capacity and the like, and the harmonic gear reducer is widely used in many fields such as robots, aerospace, precision machinery, medical devices and the like.

[0003] In the working process of the harmonic gear reducer, the flexspline is subjected to alternating cyclic loads for a long time, and stress concentration phenomenon is particularly prone to occur at the tooth root, which is an important reason for damage of the flexspline tooth ring. In order to reduce stress concentration, the existing design usually adopts the method of optimizing the structure parameters of the tooth ring. For example, by optimizing the tooth shape design, such as adopting involute tooth shape or other advanced tooth shape design, the interference and stress concentration phenomenon between the teeth can be reduced to a certain extent. However, although these optimization measures have achieved certain results, the working conditions of the harmonic gear transmission are complex and changeable, and the load and stress state borne by the flexspline are extremely complex. Therefore, to further reduce the fatigue damage risk of the flexspline, the existing technology needs to be further improved and enhanced. CONTENT OF THE UTILITY MODEL

[0004] The utility model provides a kind of harmonic reducer flexspline to at least solve or alleviate one or more technical problems in prior art, or at least provide a beneficial alternative.

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

[0006] A kind of harmonic reducer flexspline, including cylinder, the outer periphery of cylinder is equipped with tooth ring, tooth ring is made of multiple evenly arranged tooth bodies, tooth body top surface is plane, the both ends of tooth body are respectively provided with first inclined plane and second inclined plane, first inclined plane is close to cylinder top end and its slope is greater than second inclined plane, there is arc groove in the center of tooth body, so that flexspline produces radial deformation and rigid wheel engagement, reduce stress concentration, prolong the service life of flexspline.

[0007] The design of the circular-arc groove enables the tooth body to be divided into two parts for relative deformation when under stress, which helps to disperse the stress that may be concentrated at the tooth root to a larger area, thereby reducing the degree of stress concentration. When the flexspline is deformed radially under the action of the wave generator, the circular-arc groove allows the tooth body to be more flexible in adapting to such deformation. Without the groove, the tooth body may be deformed with higher stress concentration and faster fatigue damage due to the inability of the middle part to effectively release stress. During the operation of the harmonic reducer, the tooth body needs to constantly absorb and release energy. The design of the circular-arc groove helps to improve this process, enabling the energy to be more evenly distributed on the entire tooth body, reducing damage caused by excessive local energy.

[0008] In a preferred implementation, the center line of the circular-arc groove is perpendicular to the length direction of the tooth body.

[0009] In a preferred implementation, the radius r of the circular-arc groove satisfies 0.5mm≤r≤1mm.

[0010] The circular-arc groove with a radius r in the range of 0.5mm to 1mm can effectively release stress without significantly weakening the structural strength of the tooth body.

[0011] In a preferred implementation, the tooth body comprises a fitting tooth part and an extension tooth part, a second slope connects the fitting tooth part and the extension tooth part, the extension tooth part is lower in height than the fitting tooth part, the tooth groove extends from the top end of the cylinder body to the end of the extension tooth part, and the fitting tooth part is engaged with the gear groove of the rigid wheel.

[0012] In a preferred implementation, the lower layer of the gear ring is a smooth cylindrical segment, and the extension tooth part is arranged at the same height as the smooth cylindrical segment.

[0013] In a preferred implementation, the length ratio of the fitting tooth part, the extension tooth part, and the smooth cylindrical segment is L1:L2:L3=1:0.5:0.8.

[0014] In a preferred implementation, the middle part of the fitting tooth part is high and the two sides are low, and the circular-arc groove is arranged in the middle part of the fitting tooth part.

[0015] In a preferred implementation, the second slope comprises a plurality of slopes with decreasing slopes.

[0016] In a preferred implementation, the bottom of the cylinder body is provided with a flange plate, and the flange plate and the cylinder body are connected through a round corner transition structure. BRIEF DESCRIPTION OF DRAWINGS

[0017] 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:

[0018] Figure 1 A schematic embodiment of the flexible gear of the present application is shown in a perspective view;

[0019] Figure 2 An enlarged structural schematic view of a schematic embodiment of the A portion of the present application is shown; Figure 1

[0020] Figure 3 A partial structural schematic view of a schematic embodiment of the flexible gear of the present application is shown;

[0021] Label description:

[0022] 1, barrel; 10, gear ring; 100, gear body; 1001, mating tooth portion; 1002, extension tooth portion; 1003, first inclined surface; 1004, second inclined surface; 1005, circular arc groove; 101, tooth groove; 11, smooth cylindrical segment; 12, circular arc transition structure; 2, flange plate. DETAILED DESCRIPTION

[0023] Hereinafter, only certain exemplary embodiments are simply described. 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 the description are considered to be essentially exemplary rather than limiting.

[0024] In the description of the present application, it is to be 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 present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element 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 present application. In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium.

[0025] ​In the utility model, unless another explicit provision and limitation, the terms "mount", "connect", "connect", "fix" and other terms should be broad sense, for example, can be fixed connection, can also be detachable connection, or integrated; can be directly connected, can also be indirectly connected through the intermediate medium, can be two elements inside the communication or two element interaction relationship. But note that the direct connection indicates that the connection between the two main bodies does not pass through the excessive structure connection relationship, only through the connection structure is connected to form a whole. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0026] In the utility model, the description such as "first", "second" and the like is only for the purpose of description, and can not 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 feature.

[0027] The utility model is described below with reference to the accompanying drawings.

[0028] The specific scheme adopted is:

[0029] As shown in Figures 1-3 The utility model provides a kind of flexspline of harmonic reducer, including cylinder 1, the outer periphery of cylinder 1 is equipped with gear ring 10, gear ring 10 is made of multiple uniform arrangement tooth body 100, tooth body 100 top surface is plane, the two ends of tooth body 100 are provided with first inclined plane 1003 and second inclined plane 1004 respectively, first inclined plane 1003 is close to cylinder 1 top end and its gradient is greater than second inclined plane 1004, there is arc groove 1005 in the center of tooth body 100, to make flexspline produce radial deformation and rigid wheel engagement, reduce stress concentration, prolong the service life of flexspline.

[0030] By using the flexspline of harmonic reducer of the present application, the design of arc groove 1005 enables tooth body 100 to be divided into two parts for relative deformation when under stress, which helps to disperse the stress that may have been concentrated in the tooth root to a larger area, thereby reducing the degree of stress concentration. When the flexspline is deformed radially under the action of the wave generator, the arc groove 1005 allows the tooth body 100 to adapt more flexibly to such deformation. Without the groove, the tooth body 100 may experience higher stress concentration and faster fatigue damage when deformed due to the inability to effectively release stress in the middle. During the operation of the harmonic reducer, the tooth body 100 needs to constantly absorb and release energy. The design of the arc groove 1005 helps to improve this process, enabling energy to be more evenly distributed across the entire tooth body 100, reducing damage caused by excessive local energy.

[0031] As a preferred embodiment of the present application, the center line of the circular arc groove 1005 is perpendicular to the length direction of the tooth body 100. The design that the center line of the circular arc groove 1005 is perpendicular to the length direction of the tooth body 100 makes the stress more evenly dispersed to both sides of the groove when the tooth body 100 bears load. This design helps to reduce the stress concentration at the tooth root and improve the fatigue resistance of the tooth body 100.

[0032] As a preferred embodiment of the present application, the radius r of the circular arc groove 1005 satisfies 0.5mm≤r≤1mm.

[0033] If the radius r of the circular arc groove 1005 is too large, it may excessively weaken the structural strength of the tooth body 100. When the tooth body 100 bears load, it may not be able to effectively resist stress due to insufficient material at the groove, thereby causing the tooth body 100 to break or be damaged. On the contrary, if the radius r of the circular arc groove 1005 is too small, although it does not directly weaken the structural strength of the tooth body 100, it may change the stress distribution pattern of the tooth body 100, making the stress more concentrated in other parts of the tooth body 100, which may also cause the tooth body 100 to be damaged.

[0034] The radius r of the circular arc groove 1005 is set in the range of 0.5mm to 1mm, which does not significantly change the overall height of the tooth body 100. Therefore, the strength of the tooth body 100 in the height direction is maintained when it bears load, and it can resist the bending stress caused by deformation. And its depth is moderate, neither excessively weakening the structural strength of the tooth body 100, nor effectively playing the role of stress release. The circular arc groove 1005 with appropriate radius r can effectively disperse the stress of the tooth body 100 during meshing. When the tooth body 100 meshes with the rigid wheel, the stress is no longer concentrated at the tooth root, but dispersed to both sides of the groove, thereby reducing the risk of stress concentration.

[0035] Referring to Figure 2 , the tooth body 100 includes a fitting tooth part 1001 and an extension tooth part 1002, a second inclined surface 1004 connects the fitting tooth part 1001 and the extension tooth part 1002, the extension tooth part 1002 is lower in height than the fitting tooth part 1001, a tooth groove 101 extends from the top end of the cylinder 1 to the end of the extension tooth part 1002, and the fitting tooth part 1001 meshes with the tooth groove 101 of the rigid wheel.

[0036] When the harmonic reducer is in operation, the mating tooth portion 1001 engages with the gear tooth groove 101 of the rigid wheel, thereby transmitting torque and bearing load. These loads generate stress on the mating tooth portion 1001 and attempt to deform the tooth body 100. The second slope 1004, as a transition part connecting the mating tooth portion 1001 and the extended tooth portion 1002, is designed to help distribute the force on the mating tooth portion 1001 to the extended tooth portion 1002. When the mating tooth portion 1001 is subjected to load, these loads are transmitted to the extended tooth portion 1002 through the second slope 1004, thereby reducing the stress level borne by the mating tooth portion 1001 alone. Since the height of the extended tooth portion 1002 is lower than that of the mating tooth portion 1001, it provides an additional stress release area. When the force is transmitted to the extended tooth portion 1002 through the second slope 1004, these forces can be distributed over a larger area, thereby further reducing the risk of stress concentration.

[0037] Further, the second slope 1004 includes a plurality of slope-decreasing slopes. The design of the plurality of slope-decreasing slopes means that the force will undergo multiple stages of dispersion in the process of being transmitted to the extended tooth portion 1002. Each stage of slope will further distribute the force to a larger area, thereby reducing the local stress level, and the slope-decreasing slope provides a gradual transition area, so that the force can be more smoothly dispersed in the transmission process. This helps to reduce stress concentration and sudden changes in stress gradient, thereby reducing the risk of damage to the tooth body 100.

[0038] The gear tooth groove 101 extends from the top end of the cylinder 1 to the end of the extended tooth portion 1002, which helps to ensure uniform distribution of force throughout the tooth body 100. When the mating tooth portion 1001 is subjected to load, the gear tooth groove 101 can act as a stress dispersion channel to transmit the force to the extended tooth portion 1002 and other parts.

[0039] Further, the lower layer of the gear ring 10 is a smooth cylindrical segment 11, and the extended tooth portion 1002 is arranged at the same height as the smooth cylindrical segment 11.

[0040] The extended tooth portion 1002 is arranged at the same height as the smooth cylindrical segment 11, meaning that the two parts are consistent in height. This design helps to maintain the overall balance and stability of the tooth body 100, while ensuring that the extended tooth portion 1002 can fully play its role in stress dispersion.

[0041] Referring to Figure 3 The length ratio of the mating tooth portion 1001, the extended tooth portion 1002 and the smooth cylindrical segment 11 is L1:L2:L3 = 1:0.5:0.8.

[0042] The engaging tooth portion 1001 (L1) as a part directly engaged with the gear tooth groove 101 bears the main load. Its length L1 ensures sufficient engaging area and strength. The extended tooth portion 1002 (L2): The extended tooth portion 1002 with length L2 is connected with the engaging tooth portion 1001 through the second inclined surface 1004, which plays an effective force dispersion role. When the engaging tooth portion 1001 is subjected to load, the load can be evenly transmitted to the extended tooth portion 1002, reducing the stress concentration of the engaging tooth portion 1001. The smooth cylinder segment 11 (L3): The smooth cylinder segment 11 with length L3 serves as the lower structure of the tooth body 100, providing support. The reasonable length ratio design makes it easier to control the size and shape accuracy in the machining process, thereby improving the manufacturing quality.

[0043] As a preferred embodiment of the present application, the middle part of the engaging tooth portion 1001 is high and the two sides are low, and the circular arc groove 1005 is arranged in the middle part of the engaging tooth portion 1001. Because the middle part is relatively high, after slotting, the existence of the circular arc groove 1005 will not cause structural problems to the tooth. On the contrary, it helps to further disperse stress and reduce the risk of stress concentration.

[0044] As a preferred embodiment of the present application, the bottom of the cylinder body 1 is provided with a flange plate 2, and the flange plate 2 and the cylinder body 1 are connected through a round corner transition structure.

[0045] The parts not described in the present application can be realized by using or referring to the existing technology.

[0046] The above is only a specific implementation manner of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of various changes or replacements within the technical range disclosed by the present application, and these 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. A harmonic reducer flexspline characterized by, The application relates to a flexible gear wheel, which comprises a cylinder body, the outer periphery of the cylinder body is provided with a gear ring, the gear ring is composed of a plurality of uniformly arranged tooth bodies, the top surface of the tooth body is a plane, the two ends of the tooth body are respectively provided with a first inclined surface and a second inclined surface, the first inclined surface is close to the top end of the cylinder body and has a slope greater than that of the second inclined surface, and a circular-arc groove is arranged at the center of the tooth body so that the flexible gear wheel can produce radial deformation and stress concentration can be reduced when the rigid gear is engaged, thereby prolonging the service life of the flexible gear wheel.

2. The harmonic reducer flexspline of claim 1, wherein, The center line of the circular-arc groove is perpendicular to the length direction of the tooth body.

3. The harmonic reducer flexspline of claim 1, wherein, The radius r of the circular-arc groove satisfies 0.5mm<=r<=1mm.

4. The harmonic reducer flexspline of claim 1, wherein, The tooth body comprises a matching tooth part and an extension tooth part, the second inclined surface connects the matching tooth part and the extension tooth part, the height of the extension tooth part is lower than that of the matching tooth part, a tooth groove extends from the top end of the cylinder body to the end of the extension tooth part, and the matching tooth part is engaged with the tooth groove of the rigid gear.

5. The harmonic reducer flexspline of claim 3, wherein, The lower layer of the gear ring is a smooth cylinder segment, and the extension tooth part is arranged at the same height with the smooth cylinder segment.

6. The harmonic reducer flexspline of claim 3, wherein, The length ratio of the matching tooth part, the extension tooth part and the smooth cylinder segment is L1:L2:L3=1:0.5:0.

8.

7. The harmonic reducer flexspline of claim 3, wherein, The middle part of the matching tooth part is high and the two sides are low, and the circular-arc groove is arranged in the middle part of the matching tooth part.

8. The harmonic reducer flexspline of claim 3, wherein, The second inclined surface comprises a plurality of inclined surfaces with decreasing slopes.

9. The harmonic reducer flexspline of claim 1, wherein, The bottom of the cylinder body is provided with a flange plate, and the flange plate and the cylinder body are connected through a round-corner transition structure.

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