Flexible gear, harmonic reducer and industrial robot

Abstract

The invention relates to the technical field of harmonic reducers, and discloses a flexible gear, a harmonic reducer and an industrial robotic.The flexible gear comprises a cylinder, a tooth part, a cylinder part, a bent part, a diaphragm part and a flange part are sequentially arranged in the axial direction of the cylinder, the wall thickness of the connecting position of the cylinder part and the bent part is t1, and the wall thickness of the connecting position of the cylinder part and the diaphragm part is t2. The wall thickness of the connecting position of the bent part and the diaphragm part is t2, the wall thickness of the connecting position of the diaphragm part and the flange part is t3, and t2 is larger than t3 and larger than t1. T2 is larger than or equal to t3 and larger than t1, so that the wall thickness of the joint of the diaphragm part and the flange part and the wall thickness of the joint of the bent part and the diaphragm part are large, the deformation bearing capacity of the flexible gear can be improved, stress concentration is reduced, the risk that the flexible gear is fractured and fails due to deformation is reduced, the fatigue strength of the flexible gear is improved, and the service life of the flexible gear is prolonged; therefore, the reliability of the harmonic reducer is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of harmonic reducers, and in particular to a flexspline, a harmonic reducer and an industrial robot. Background Art

[0002] The harmonic reducer drives the flexible wheel to deform through a wave generator so that the flexible wheel meshes with the rigid wheel, thereby realizing the transmission of motion. Due to the inherent characteristics of harmonic gears, the meshing area between the flexible wheel and the rigid wheel is large, making its load-bearing capacity higher. When the harmonic reducer is running, the flexible wheel needs to withstand the alternating stress applied by the wave generator and the meshing torque applied by the rigid wheel. However, the high load will cause the flexible wheel to deform repeatedly, resulting in tearing and other failures in the thin-walled position of the flexible wheel, especially near the flange, affecting the operation of the harmonic reducer. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a flexible wheel, which can improve the service life and reliability through reasonable wall thickness design.

[0004] The present invention also provides a harmonic reducer having the above-mentioned flexible wheel and an industrial robot using the harmonic reducer.

[0005] According to the first aspect of the present invention, the flexible wheel includes a cylinder, and a tooth portion, a cylinder portion, a bending portion, a diaphragm portion and a flange portion are sequentially arranged along the axial direction of the cylinder, the wall thickness of the connection between the cylinder portion and the bending portion is t1, the wall thickness of the connection between the bending portion and the diaphragm portion is t2, and the wall thickness of the connection between the diaphragm portion and the flange portion is t3, satisfying: t3≥t2>t1.

[0006] According to the first aspect of the present invention, the flexible wheel has at least the following beneficial effects: a tooth portion is provided at one end of the cylinder, and a flange portion is provided at the other end of the cylinder, and the torque of the wave generator can be transmitted to the flange portion through the flexible wheel, so as to output the torque through the flange portion. Along the axial direction of the cylinder, the tooth portion, the cylinder portion, the bending portion, the diaphragm portion and the flange portion are connected in sequence, and by designing t3≥t2>t1, the wall thickness of the connection between the diaphragm portion and the flange portion and the connection between the bending portion and the diaphragm portion is large, which can improve the bearing capacity of the flexible wheel deformation, reduce the concentration of stress, reduce the risk of the flexible wheel breaking and failing due to deformation, improve the fatigue strength of the flexible wheel, and extend the service life of the flexible wheel, thereby improving the reliability of the harmonic reducer.

[0007] According to some embodiments of the first aspect of the present invention, the wall thickness of the connection between the tooth portion and the barrel portion is t4, satisfying: t4>t3≥t2>t1.

[0008] According to some embodiments of the first aspect of the present invention, the minimum wall thickness of the diaphragm is t5, satisfying: t4>t3≥t2>t1>t5.

[0009] According to some embodiments of the first aspect of the present invention, the inner hole diameter of the cylinder is D1, which satisfies: D1*1%≥t4≥D1*0.6%.

[0010] According to some embodiments of the first aspect of the present invention, external teeth are provided on the outer wall of the tooth portion, and the pitch circle diameter of the external teeth is D2, satisfying: D2*1.2%≥t4≥D2*0.5%.

[0011] According to some embodiments of the first aspect of the present invention, on the axial cross-sectional plane of the cylinder, the side wall contour line of the diaphragm away from the cylinder is a first straight line, the side wall contour line of the diaphragm close to the cylinder is a first circular arc line, and the first circular arc line protrudes toward the first straight line.

[0012] According to some embodiments of the first aspect of the present invention, a side wall contour line of the bent portion close to the barrel portion is a second circular arc line, and the first circular arc line is tangent to the second circular arc line.

[0013] According to some embodiments of the first aspect of the present invention, on the axial cross-sectional plane of the cylinder, the inner wall contour line of the cylinder portion is a second straight line, the outer wall contour line of one end of the cylinder portion facing the bending portion is a third arc line, and the third arc line protrudes toward the second straight line.

[0014] According to some embodiments of the first aspect of the present invention, a side wall contour line of the bent portion close to the barrel portion is a second circular arc line, and the third circular arc line is tangent to the second circular arc line.

[0015] According to some embodiments of the first aspect of the present invention, the outer wall contour line of the cylinder also includes a fourth arc line and a third straight line, both ends of the fourth arc line connect the third arc line and the third straight line, and the fourth arc line protrudes in a direction away from the second straight line.

[0016] According to the second aspect of the present invention, the harmonic reducer comprises a rigid wheel, a wave generator and the flexible wheel described in the first aspect, wherein the rigid wheel is sleeved on the outside of the flexible wheel, the rigid wheel is provided with internal teeth matching the tooth portion, the flexible wheel is sleeved on the outside of the wave generator, and the wave generator abuts against the inner wall of the tooth portion.

[0017] The harmonic reducer according to the embodiment of the second aspect of the present invention has at least the following beneficial effects: the wave generator is installed on the inner side of the flexible wheel, the flexible wheel is installed on the inner side of the rigid wheel, the wave generator drives the flexible wheel to rotate, so that the outer teeth of the flexible wheel mesh with the inner teeth of the rigid wheel, and the rotation and torque are transmitted through the flexible wheel. The flexible wheel is set with t3≥t2>t1, so that the wall thickness of the connection between the diaphragm and the flange part and the connection between the bending part and the diaphragm part is large, which can improve the bearing capacity of the flexible wheel deformation, reduce the concentration of stress, reduce the risk of the flexible wheel breaking and failing due to deformation, improve the fatigue strength of the flexible wheel, and extend the service life of the flexible wheel, thereby improving the reliability of the harmonic reducer.

[0018] The industrial robot according to the third aspect of the present invention comprises the harmonic reducer according to the second aspect of the present invention. By adopting the harmonic reducer according to the second aspect of the present invention, the industrial robot can move smoothly, the maintenance frequency of the industrial robot is reduced, the use cost is reduced, and the reliability of the industrial robot is improved.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments in conjunction with the accompanying drawings, in which:

[0021] Figure 1 A cross-sectional view of a harmonic reducer according to an embodiment of the second aspect of the present invention;

[0022] Figure 2 is a cross-sectional view of a flexible wheel according to an embodiment of the first aspect of the present invention;

[0023] Figure 3 for Figure 2 Partial cross-sectional view at point A.

[0024] The figures are as follows:

[0025] Cylinder 100, tooth portion 110, cylinder portion 120, second straight line 121, third arc line 122, fourth arc line 123, third straight line 124, bending portion 130, second arc line 131, diaphragm 140, first straight line 141, first arc line 142, flange portion 150;

[0026] Ganglun 200;

[0027] Wave generator 300. DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0029] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0030] In the description of the present invention, if there is a description of first and second, it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0031] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0032] A harmonic gear reducer is a reducer consisting of a fixed internal gear rigid wheel, a flexible wheel, and a wave generator that causes the flexible wheel to deform radially. The flexible wheel is sleeved on the outside of the wave generator, and the rigid wheel is sleeved on the outside of the flexible wheel. The wave generator drives the flexible wheel to deform radially and rotate, causing the flexible wheel to generate a controllable elastic deformation wave, causing the teeth of the rigid wheel and the flexible wheel to be relatively staggered to transmit power and motion. Due to the inherent characteristics of the harmonic reducer, the meshing area of ​​the flexible wheel and the rigid wheel is large, so its load-bearing capacity is relatively high, making the harmonic reducer widely used in electronics, aerospace, industrial robots and other fields. The application scenarios of harmonic reducers tend to be small equipment. At present, harmonic reducers It is developing towards high speed, high rigidity, long life, etc. At the same time, the test on flexible wheels and flexible bearings is also more stringent. In order to facilitate manufacturing, the inner wall of the existing flexible wheel is straight, so that the wall thickness of the flexible wheel is uniform. When the harmonic reducer is running, the flexible wheel needs to withstand the alternating stress applied by the wave generator and the meshing torque applied by the rigid wheel. However, the high-load torque will cause the flexible wheel to deform, and the flexible wheel with uniform wall thickness has poor ability to absorb deformation, which can easily lead to the flexible wheel breaking and failure due to repeated deformation, especially at the flange edge, where the torsional stress is the largest and it is most likely to have failure problems such as tearing, thereby reducing the service life and reliability of the harmonic reducer.

[0033] Based on this, the present invention provides a flexible wheel applied to a harmonic reducer, which can improve the ability to withstand deformation, reduce stress concentration, extend the service life of the flexible wheel, and improve the reliability of the harmonic reducer.

[0034] The following is a description with reference to the accompanying drawings:

[0035] Reference Figures 1 to 3 In a first aspect of the present invention, an embodiment of the present invention proposes a flexible wheel, which is applied to a harmonic reducer. The main body of the flexible wheel is a cylinder 100, one end of the cylinder 100 is open and the outer wall is provided with a tooth portion 110, so that the cylinder 100 can be mounted on a wave generator 300 of the harmonic reducer. A flange portion 150 is provided at the other end of the cylinder 100. The flange portion 150 is the output end of the harmonic reducer and is used to connect other devices to transmit motion and torque to other devices. Along the axial direction of the cylinder 100, the cylinder 100 includes a tooth portion 110, a cylinder portion 120, a bending portion 130, a diaphragm 140 and a flange portion 150 which are connected in sequence. The tooth portion 110 is a part of the cylinder 100 provided with external teeth. One end of the cylinder 120 is connected to the tooth portion 110, and the other end is connected to the bending portion 130. The bending portion 130 is turned from the axial direction of the cylinder 100 to the radial direction of the cylinder 100. The flange portion 150 is used to connect the load. The diaphragm 140 is a connecting structure between the flange portion 150 and the bending portion 130, and is roughly distributed along the radial direction of the cylinder 100. The wall thickness of the connection between the cylinder 120 and the bending portion 130 is set to t1, the wall thickness of the connection between the bending portion 130 and the diaphragm 140 is set to t2, and the wall thickness of the connection between the diaphragm 140 and the flange 150 is set to t3. The design requires t3≥t2>t1, so that the wall thickness of the connection between the diaphragm 140 and the flange 150 and the connection between the bending portion 130 and the diaphragm 140 is relatively large, both of which are greater than the wall thickness of the connection between the cylinder 120 and the bending portion 130. By increasing the wall thickness, the fatigue resistance and tearing resistance of the flexible wheel can be improved, which is beneficial to the transmission of torque and improves durability.

[0036] One end of the cylinder 100 is open and can be connected to the wave generator 300. The other end of the cylinder 100 is a flange 150. The load can be connected to the flexible wheel through the flange 150. The load is driven to move by the flexible wheel, and the movement and torque are transmitted by the flexible wheel. During the operation of the harmonic reducer, the flexible wheel must repeatedly withstand deformation and torque. By designing t3≥t2>t1, the wall thickness of the connection between the diaphragm 140 and the flange 150 and the connection between the bending part 130 and the diaphragm 140 is larger, both of which are greater than the wall thickness of the connection between the cylinder 120 and the bending part 130. By increasing the wall thickness, the deformation bearing capacity of the flexible wheel can be improved, the stress concentration can be reduced, the risk of the flexible wheel breaking and failing due to deformation can be reduced, and the fatigue strength of the flexible wheel can be improved. In particular, the connection between the diaphragm 140 and the flange 150 can withstand greater stress and torsional force, which is beneficial to extending the service life of the flexible wheel, thereby improving the reliability of the harmonic reducer.

[0037] It should be noted that, refer to Figure 1 The wave generator 300 is arranged at the opening of the cylinder 100, and the steel wheel 200 is mounted on the outside of the cylinder 100. The rigid wheel 200 and the flexible wheel have teeth with the same modulus, but different numbers of teeth. Usually, the number of teeth of the flexible wheel is two less than that of the rigid wheel 200. The difference in the number of teeth of the harmonic drive represents the deformation wave number of the flexible wheel. In the free state (without the wave generator 300), the rigid wheel 200 and the flexible wheel are in a concentric position, and the gaps between the teeth of the rigid wheel 200 and the flexible wheel are uniform. The wave generator 300 is usually elliptical. The wave generator 300 causes the flexible wheel to deform radially and become an ellipse. On the long axis of the ellipse, the steel wheel 200 is partially meshed with the flexible wheel, and on the short axis, a radial gap is formed. The wave generator 300 drives the flexible wheel to rotate. During the rotation of the generator, the shape of the flexible wheel is always close to the above shape. Among them, due to the differential tooth meshing torque generated when the rigid wheel 200 and the flexible wheel are meshed, the flexible wheel is bent and deformed. Since the flange portion 150 is connected to the load and serves as the output end, the stress at the connection between the flange portion 150 and the diaphragm portion 140 is relatively large, which is prone to fatigue or even tearing and failure. Therefore, by designing the wall thickness of the flexible wheel, the wall thickness of the connection between the cylinder portion 120 and the bending portion 130 is used as a reference, and the wall thickness of the connection between the diaphragm portion 140 and the flange portion 150 and the connection between the bending portion 130 and the diaphragm portion 140 is increased, thereby improving the deformation bearing capacity of the flexible wheel, reducing stress concentration, reducing the risk of fracture and failure of the flexible wheel due to deformation, and improving the fatigue strength of the flexible wheel.

[0038] Reference Figure 3 , the wall thickness of the connection between the tooth portion 110 and the barrel portion 120 is set to t4, and t4>t3≥t2>t1 is set in the design. Considering that the connection between the tooth portion 110 and the barrel portion 120 will generate a differential tooth meshing torque when the rigid wheel 200 and the flexible wheel are meshed, the wall thickness of the connection between the tooth portion 110 and the barrel portion 120 is designed to be greater than the wall thickness of the connection between the diaphragm portion 140 and the flange portion 150. The use of a larger wall thickness is conducive to improving the ability to withstand deformation, being able to withstand greater stress, meeting the requirements of torque transmission, reducing the risk of the flexible wheel breaking and failing due to deformation, and improving the service life. It can be understood that the end face of the tooth portion 110 is usually set as an inclined surface, and the inclined surface transitions to the barrel portion 120. The wall thickness of the connection between the tooth portion 110 and the barrel portion 120 is increased by design, which can withstand greater stress and deformation and improve the reliability of use.

[0039] Reference Figure 3The wall thickness of the connection between the tooth portion 110 and the cylinder portion 120 is set to t4, and the minimum wall thickness of the diaphragm 140 is set to t5. In the design, t4>t3≥t2>t1>t5 is set, so that the wall thickness of the connection between the tooth portion 110 and the cylinder portion 120 is greater than the wall thickness of the connection between the diaphragm portion 140 and the flange portion 150, and the wall thickness of the connection between the cylinder portion 120 and the bending portion 130 is greater than the minimum wall thickness of the diaphragm 140. Taking the minimum wall thickness of the diaphragm 140 as a reference, the wall thickness of each part of the cylinder 100 is greater than the minimum wall thickness of the diaphragm 140. The use of a larger wall thickness at each part of the cylinder 100 is conducive to improving the ability to withstand deformation, being able to withstand greater stress, reducing the risk of the flexible wheel breaking and failing due to deformation, and improving the service life.

[0040] Reference Figure 2 and Figure 3 It can be understood that, in some embodiments, when the wave generator 300 is not installed on the flexible wheel, the inner hole of the cylinder 100 is a circular hole, and thus the inner hole diameter of the cylinder 100 is set to D1, and the design satisfies: D1*1%≥t4≥D1*0.6%, and the wall thickness of the connection between the tooth portion 110 and the cylinder portion 120 is designed according to the inner hole diameter of the cylinder 100, and is limited to between 0.6% and 1% of the inner hole diameter of the cylinder 100, so that the wall thickness of the connection between the tooth portion 110 and the cylinder portion 120 meets the strength and stiffness requirements of the transmitted torque, and can withstand the differential tooth meshing torque generated when the rigid wheel 200 and the flexible wheel are meshed, thereby reducing the risk of the flexible wheel breaking and failing due to deformation and improving the service life.

[0041] Reference Figure 2 and Figure 3 It can be understood that in other embodiments, when the wave generator 300 is not installed on the flexible wheel, the outer contour of the cylinder 100 is circular, the outer wall of the tooth portion 110 is provided with external teeth, and the pitch circle diameter of the external teeth is set to D2, which satisfies the following design conditions: D2*1.2%≥t4≥D2*0.5%, and the wall thickness at the connection between the tooth portion 110 and the cylinder portion 120 is designed according to the pitch circle of the external teeth, and is limited to between 0.5% and 1.2% of the pitch circle diameter of the external teeth, so that the wall thickness at the connection between the tooth portion 110 and the cylinder portion 120 meets the strength and stiffness requirements of the transmitted torque, can withstand the differential tooth meshing torque generated when the rigid wheel 200 is meshing with the flexible wheel, reduces the risk of the flexible wheel breaking and failing due to deformation, and improves its service life.

[0042] Reference Figure 2 and Figure 3It can be understood that, on the axial cross-section of the cylinder 100, the inner side surface of the diaphragm 140, that is, the side wall contour line away from the cylinder 120 is the first straight line 141, and the outer side surface of the diaphragm 140, that is, the side wall contour line close to the cylinder 120 is the first arc line 142, wherein the first arc line 142 is set to bulge toward the first straight line 141, so that the minimum wall thickness of the diaphragm 140 is approximately located in the middle of the diaphragm 140, and the distance between the minimum wall thickness and the flange portion 150 is close to the distance between the minimum wall thickness and the bending portion 130, so that the force is more balanced and the stress concentration is reduced. Since the diaphragm 140 is close to being distributed radially along the cylinder 100, the radial force-bearing area of ​​the diaphragm 140 is relatively large during rotation. Therefore, the minimum wall thickness of the cylinder 100 can be set at the diaphragm 140, which can meet the requirements of transmitting motion and torque. The wall thicknesses at other positions of the cylinder 100 are greater than the minimum wall thickness of the diaphragm 140, have suitable strength and rigidity, can withstand torque, and help improve the service life of the flexible wheel.

[0043] Reference Figure 2 and Figure 3 It can be understood that the bending portion 130 is the connection portion between the cylinder 120 and the diaphragm 140, and realizes reversal. The bending portion 130 is usually designed to be an arc surface transition. Therefore, the outer side surface of the bending portion 130, that is, the side wall contour line close to the cylinder 120 is a second arc line 131, and the first arc line 142 of the diaphragm 140 is tangent to the second arc line 131 of the bending portion 130. The diaphragm 140 and the bending portion 130 are connected by a smooth curved surface, which reduces stress concentration and is beneficial to improving the reliability of the flexible wheel.

[0044] Reference Figure 2 and Figure 3 It can be understood that, on the axial section of the cylinder 100, the inner wall contour line of the cylinder 120 is the second straight line 121, and the outer wall contour line of the cylinder 120 includes a third arc line 122, a fourth arc line 123 and a third straight line 124, wherein the third arc line 122 is located at one end close to the bending portion 130, and the third straight line 124 is located at one end close to the tooth portion 110, and both ends of the fourth arc line 123 connect the third arc line 122 and the third straight line 124, the third arc line 122 is convexly arranged toward the second straight line 121, and the fourth arc line 123 is convexly arranged away from the second straight line 121, the third arc line 122 is tangent to the second arc line 131, and the third arc line 122 is also tangent to the fourth arc line 123, the cylinder 120 and the bending portion 130 are connected by a smooth curved surface, and the outer wall parts of the cylinder 120 have a smooth transition, which reduces stress concentration and is conducive to improving the reliability of the flexible wheel.

[0045] Reference Figure 1The harmonic reducer proposed in the second embodiment of the present invention includes a rigid wheel 200, a wave generator 300 and a flexible wheel of the first embodiment. The rigid wheel 200 is mounted on the outside of the flexible wheel. The rigid wheel is provided with internal teeth. The tooth portion 110 of the flexible wheel is provided with external teeth. The flexible wheel is mounted on the outside of the wave generator 300, and the wave generator 300 abuts against the inner wall of the tooth portion 110. The internal teeth of the rigid wheel 200 and the external teeth of the flexible wheel are gear teeth with the same module, but different numbers of teeth. Usually, the number of teeth of the flexible wheel is 2 less than that of the rigid wheel 200. The difference in the number of teeth of the harmonic drive represents the deformation wave number of the flexible wheel. In the free state (without the wave generator 300), the rigid wheel 200 and the flexible wheel are in a concentric position, and the gaps between the teeth of the rigid wheel 200 and the flexible wheel are uniform. The wave generator 300 is usually elliptical, and the wave generator 300 undergoes radial deformation to become an ellipse. On the long axis of the ellipse, the steel wheel 200 is meshed with part of the teeth 110 of the flexible wheel, and a radial gap is formed on the short axis. The wave generator 300 drives the flexible wheel to rotate, and during the rotation of the generator, the shape of the flexible wheel is always close to the above shape. Among them, due to the differential tooth meshing torque generated when the rigid wheel 200 and the flexible wheel are meshed, the flexible wheel is bent and deformed.

[0046] Reference Figure 2 and Figure 3 The main body of the flexible wheel is a cylinder 100. Along the axial direction of the cylinder 100, the cylinder 100 includes a tooth portion 110, a cylinder 120, a bending portion 130, a diaphragm 140 and a flange portion 150 which are connected in sequence. The wall thickness of the connection between the cylinder 120 and the bending portion 130 is set to t1, the wall thickness of the connection between the bending portion 130 and the diaphragm 140 is set to t2, and the wall thickness of the connection between the diaphragm 140 and the flange portion 150 is set to t3. The design requires t3≥t2>t1, so that the wall thickness of the connection between the diaphragm 140 and the flange portion 150 and the connection between the bending portion 130 and the diaphragm 140 is larger, both of which are greater than the wall thickness of the connection between the cylinder 120 and the bending portion 130. By increasing the wall thickness, the fatigue resistance and tear resistance of the flexible wheel can be improved, which is beneficial to the transmission of torque and improves durability.

[0047] The harmonic reducer drives the load to move through the flexible wheel, and both the movement and torque are transmitted by the flexible wheel. During the operation of the harmonic reducer, the flexible wheel must repeatedly withstand deformation and torque. By designing t3≥t2>t1, the wall thickness of the connection between the diaphragm 140 and the flange 150 and the connection between the bending part 130 and the diaphragm 140 is larger, both of which are greater than the wall thickness of the connection between the cylinder 120 and the bending part 130. By increasing the wall thickness, the deformation bearing capacity of the flexible wheel can be improved, the stress concentration can be reduced, the risk of the flexible wheel breaking and failing due to deformation can be reduced, and the fatigue strength of the flexible wheel can be improved, especially the connection between the diaphragm 140 and the flange 150, which can withstand greater stress and torsional force, which is beneficial to prolonging the service life of the flexible wheel, thereby improving the reliability of the harmonic reducer.

[0048] In addition, the harmonic reducer includes all the technical solutions of the flexible wheel and has all the technical effects of the flexible wheel, which will not be elaborated one by one.

[0049] The industrial robot of the third embodiment of the present invention includes the harmonic reducer of the second embodiment. The industrial robot may be a handling robot, a welding robot, an assembly robot, a processing robot, a spraying robot, a cleaning robot, a collaborative robot, etc. The harmonic reducer of the second embodiment of the present invention is applied to the industrial robot. The harmonic reducer includes a rigid wheel 200, a wave generator 300 and a flexible wheel of the first embodiment. The rigid wheel 200 is mounted on the outside of the flexible wheel, the rigid wheel is provided with internal teeth, the tooth portion 110 of the flexible wheel is provided with external teeth, the flexible wheel is mounted on the outside of the wave generator 300, and the wave generator 300 abuts against the inner wall of the tooth portion 110. The inner teeth of the rigid wheel 200 and the outer teeth of the flexible wheel are gear teeth with the same module, but different numbers of teeth. Usually, the number of teeth of the flexible wheel is 2 less than that of the rigid wheel 200. The difference in the number of teeth of the harmonic drive represents the deformation wave number of the flexible wheel. In the free state (without the wave generator 300), the rigid wheel 200 and the flexible wheel are in a concentric position, and the gaps between the teeth of the rigid wheel 200 and the flexible wheel are uniform. The wave generator 300 is usually elliptical, and the wave generator 300 undergoes radial deformation to become an ellipse. On the long axis of the ellipse, the steel wheel 200 is meshed with part of the tooth portion 110 of the flexible wheel, and on the short axis, a radial gap is formed. The wave generator 300 drives the flexible wheel to rotate, and during the rotation of the generator, the shape of the flexible wheel is always close to the above-mentioned shape. Among them, due to the differential tooth meshing torque generated when the rigid wheel 200 and the flexible wheel are meshed, the flexible wheel is bent and deformed.

[0050] Reference Figure 2 and Figure 3 The main body of the flexible wheel is a cylinder 100. Along the axial direction of the cylinder 100, the cylinder 100 includes a tooth portion 110, a cylinder 120, a bending portion 130, a diaphragm 140 and a flange portion 150 which are connected in sequence. The wall thickness of the connection between the cylinder 120 and the bending portion 130 is set to t1, the wall thickness of the connection between the bending portion 130 and the diaphragm 140 is set to t2, and the wall thickness of the connection between the diaphragm 140 and the flange portion 150 is set to t3. The design requires t3≥t2>t1, so that the wall thickness of the connection between the diaphragm 140 and the flange portion 150 and the connection between the bending portion 130 and the diaphragm 140 is larger, both of which are greater than the wall thickness of the connection between the cylinder 120 and the bending portion 130. By increasing the wall thickness, the fatigue resistance and tear resistance of the flexible wheel can be improved, which is beneficial to the transmission of torque and improves durability.

[0051] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. Flexspline, characterized in that: include: The cylinder body is provided with a tooth portion, a cylinder portion, a bending portion, a diaphragm portion and a flange portion in sequence along the axial direction of the cylinder body. The wall thickness at the connection between the cylinder portion and the bending portion is t1, the wall thickness at the connection between the bending portion and the diaphragm portion is t2, and the wall thickness at the connection between the diaphragm portion and the flange portion is t3, satisfying: t3≥t2>t1.

2. The flexible wheel according to claim 1, characterized in that: The wall thickness of the connection between the tooth portion and the cylinder portion is t4, which satisfies: t4>t3≥t2>t1.

3. The flexible wheel according to claim 2, characterized in that: The minimum wall thickness of the diaphragm is t5, satisfying: t4>t3≥t2>t1>t5.

4. The flexible wheel according to claim 2, characterized in that: The inner hole diameter of the cylinder is D1, which satisfies: D1*1%≥t4≥D1*0.6%.

5. The flexible wheel according to claim 2, characterized in that: The outer wall of the tooth portion is provided with external teeth, and the pitch circle diameter of the external teeth is D2, satisfying: D2*1.2%≥t4≥D2*0.5%.

6. The flexible wheel according to claim 1, characterized in that: On the axial section of the cylinder, the side wall contour line of the diaphragm away from the cylinder is a first straight line, and the side wall contour line of the diaphragm close to the cylinder is a first arc line, and the first arc line protrudes toward the first straight line.

7. The flexible wheel according to claim 6, characterized in that: A side wall contour line of the bent portion close to the barrel portion is a second arc line, and the first arc line is tangent to the second arc line.

8. The flexible wheel according to claim 1, characterized in that: On the axial section of the cylinder, the inner wall contour line of the cylinder is a second straight line, the outer wall contour line of one end of the cylinder facing the bending portion is a third arc line, and the third arc line protrudes toward the second straight line.

9. The flexible wheel according to claim 8, characterized in that: A side wall contour line of the bent portion close to the barrel portion is a second arc line, and the third arc line is tangent to the second arc line.

10. The flexible wheel according to claim 8 or 9, characterized in that: The outer wall contour line of the cylinder also includes a fourth arc line and a third straight line. Two ends of the fourth arc line connect the third arc line and the third straight line. The fourth arc line protrudes in a direction away from the second straight line.

11. Harmonic reducer, characterized in that: It comprises a rigid wheel, a wave generator and a flexible wheel as claimed in any one of claims 1 to 10, wherein the rigid wheel is sleeved on the outside of the flexible wheel, the rigid wheel is provided with internal teeth matching the tooth portion, the flexible wheel is sleeved on the outside of the wave generator, and the wave generator abuts against the inner wall of the tooth portion.

12. An industrial robot, characterized in that Including the harmonic reducer as claimed in claim 11.

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