A harmonic reducer and driver

Abstract

The present invention provides a harmonic reducer, comprising a flexible wheel, a fixed wheel and an output member, wherein the fixed wheel is provided with internal teeth, and the flexible wheel comprises a meshing portion and a pusher dog; the meshing portion is cylindrical with external teeth; the tooth shapes of the external teeth and the internal teeth are the same, and the number of teeth of the external teeth is less than the number of teeth of the internal teeth; after the meshing portion is actuated and deformed, the external teeth and the internal teeth are meshed and transmitted; the pusher dog is arranged at one end of the meshing portion and is connected to the output member for transmission. The harmonic reducer provided by the present invention only generates two-dimensional deformation during flexible wheel transmission, which reduces the internal stress in the transmission process and improves the service life and transmission efficiency. The present invention also provides a driver. The harmonic reducer and driver provided by the present invention have the advantages of high transmission efficiency, long service life, large output torque and low cost.

Description

Technical Field

[0001] The present invention relates to the field of robotics technology, and in particular to a harmonic reducer and a driver. Background Art

[0002] At present, the key joints of robots are all equipped with harmonic reducers. Compared with other reducers, under the same speed ratio and the same load, the harmonic reducer has smooth transmission, the highest precision, small structure volume, and light weight. It is widely used in precision industries such as robots, CNC machine tools, and semiconductor equipment. Harmonic reducers generally include fixed wheels, flexible wheels, and wave generators containing flexible bearings. Torque output is transmitted through thin-walled deformable flexible wheels; the flexible wheels are usually cup-shaped or top-hat-shaped, with thin walls and a right angle portion close to 90 degrees. The flexible wheel of this structure has high requirements on the performance of steel. It needs to ensure the elasticity requirements while ensuring its hardness. Generally, imported alloy steel is used, and the processing accuracy requirements are relatively high. Due to its special materials and high production process requirements, its cost and price are much higher than other types of reducers. The complex manufacturing process of harmonic reducers leads to its high cost, which has become one of the obstacles to the popularization and application of robots.

[0003] The harmonic reducer with cylindrical flexible wheel has no 90-degree thin-wall structure, which eliminates stress concentration, enhances the load capacity and impact resistance of the harmonic reducer, greatly improves its fatigue life, and also greatly reduces the processing difficulty and cost of the harmonic reducer. However, since the flexible wheel of this type of harmonic reducer is a dynamic three-dimensional curved surface deformation during the output rotation process, a thin-walled flexible wheel can reduce internal stress and have high transmission efficiency, but it will lead to a decrease in output torque capacity; a thick-walled flexible wheel can increase output torque, but it will increase internal stress and reduce transmission efficiency. Summary of the invention

[0004] In order to solve at least one of the above technical problems, the purpose of the present invention is to provide a harmonic reducer and driver that have high transmission efficiency, long service life, large output torque and low cost. At the same time, the harmonic reducer and driver are simple to manufacture, low in cost, and convenient for large-scale production and application.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A harmonic reducer is provided, comprising a flexible wheel, a fixed wheel and an output member, wherein the fixed wheel is provided with internal teeth, and the flexible wheel comprises a meshing portion and a pusher dog; the meshing portion is cylindrical with external teeth; the external teeth and the internal teeth have the same tooth shape, and the number of teeth of the external teeth is less than the number of teeth of the internal teeth; after the meshing portion is actuated and deformed, the external teeth and the internal teeth are meshed; the pusher dog is provided at one end of the meshing portion and is transmission-connected to the output member.

[0007] Furthermore, the external teeth are teeth arranged on the outer circumferential surface of the meshing portion, extending along the axial direction and evenly spaced in a circumferential ring shape, and the inner circumferential surface of the meshing portion is a smooth surface.

[0008] Furthermore, there are multiple pusher claws, which are evenly spaced and distributed in a circle.

[0009] Furthermore, the pusher claw is a cylinder.

[0010] Furthermore, it also includes a wave generator component, which actuates the meshing portion to deform so that the cross-section of the meshing portion changes from a circle to an ellipse; after the meshing portion is deformed, a certain gap exists between the outer teeth and the inner teeth in the major axis direction of the ellipse, and between the outer teeth and the inner teeth in the minor axis direction.

[0011] Furthermore, the output member includes a dial and an output shaft, the dial is provided with a dial groove; the dial claw is transmission-connected to the output member via the dial groove.

[0012] Furthermore, the shift groove is a bar hole arranged along the radial direction of the dial, and the extension line of the bar hole converges at the central axis of the dial; the number of the shift grooves is the same as the number of the shift claws, the shift grooves are adapted to the shapes of the shift claws, and the shift claws can slide in the radial direction of the dial in the shift grooves.

[0013] Furthermore, after the meshing portion is deformed, the plurality of pusher claws are distributed in the elliptical manner.

[0014] Furthermore, it also includes a shell assembly, which includes a shell and a shell cover; the shell and the shell cover are connected to form an installation cavity; the flexible wheel, the fixed wheel and the wave generator assembly are arranged in the installation cavity.

[0015] Furthermore, during transmission, the pusher claw slides radially relative to the pusher groove along the dial; the movement trajectory of the pusher claw relative to the housing assembly is a small elliptical trajectory of the pusher claw itself formed by the large elliptical rotational motion of the flexible wheel relative to the dial.

[0016] The present invention also provides a driver, comprising a motor and the above-mentioned harmonic reducer, wherein the harmonic reducer is installed at the output end of the motor.

[0017] Compared with the prior art, the harmonic reducer and driver provided by the present invention have the following beneficial effects: in the harmonic reducer provided by the present application, the flexible wheel as a whole only presents a deformation rotation with an elliptical cross section, because the pusher claw can slide radially in the pusher groove during the harmonic reduction transmission process, that is, only a two-dimensional deformation of the cylindrical surface is generated, and the three-dimensional twisting deformation of the flexible wheel which is an overall cylindrical shape will not occur. The two-dimensional deformation of the flexible wheel during transmission in the present application reduces the internal stress during the transmission process, can protect the elasticity of the flexible wheel, and improve the service life of the harmonic reducer; at the same time, due to the reduction in deformation, the transmission efficiency is also improved.

[0018] The harmonic reducer provided in the present application has a separate arrangement of the housing and the stator, which reduces the difficulty of machining the internal teeth on the stator and reduces the cost; the flexible wheel is composed of a meshing part and a pusher claw, which has a simple structure, requires less material and reduces the cost.

[0019] The flexible wheel of the harmonic reducer provided in the present application is composited by using meshing parts and pusher claws made of different elastic materials. During the transmission process, it can overcome the defect of relatively low strength of the pusher claws, form a flexible wheel with complementary elasticity and strength, and improve the transmission efficiency and service life of the entire harmonic reducer.

[0020] When the flexible pulley finger provided by the present application is meshed with the dial, the motion trajectory of each cylindrical pulley is a small elliptical trajectory of the pulley itself formed by the rotational motion of the large ellipse generated by the flexible pulley relative to the dial. By setting the diameter of the pulley cylinder and the width of the pull slot, the different degrees of tightness of the two can be adjusted. Since the width of the pull slot is a fixed value, the pulley slides along the radial direction of the dial relative to the pull slot during the transmission process, and the pulley moves in its own small elliptical trajectory generated by the housing assembly. Therefore, during the transmission process, the pulley squeezes the side wall of the pull slot, generating corresponding deformation stress, so that the two are tightly combined, thereby eliminating the transmission backlash.

[0021] The structure of the flexible wheel with a pusher claw provided in the present application allows the flexible wheel to withstand relatively large elliptical deformation during transmission, so the reduction ratio of the harmonic reducer provided in the present application can be less than 35, which is more suitable for application in the field of lightweight service robots.

[0022] The flexible wheel structure provided by the present application can set the flexible wheel to have a sufficient thickness and will not cause too much change in internal stress, so it has a larger coupling range when designing fatigue life, which is conducive to the design of improving fatigue life. It is also conducive to the structural design of the fatigue life of the pusher claw and the extension of the service life of the flexible wheel.

[0023] In summary, the present invention provides a harmonic reducer and driver that have high transmission efficiency, long service life, large output torque and low cost. At the same time, the harmonic reducer and driver are simple to manufacture, low in cost, and convenient for large-scale production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The overall structure of a driver with a harmonic reducer according to a specific embodiment of the present invention is schematically shown;

[0025] Figure 2 Schematically shows an exploded view of a driver with a harmonic reducer according to a specific embodiment of the present invention;

[0026] Figure 3 A schematic diagram showing the internal structure of a driver with a harmonic reducer according to a specific embodiment of the present invention from one perspective;

[0027] Figure 4 The internal structure diagram of a driver with a harmonic reducer according to a specific embodiment of the present invention is schematically shown from another perspective;

[0028] Figure 5 A schematic diagram of the structure of a flexible pulley from one perspective according to a specific embodiment of the present invention is shown;

[0029] Figure 6 A schematic diagram of the structure of a flexible pulley from another perspective according to a specific embodiment of the present invention is shown;

[0030] Figure 7 A partial internal structure diagram of a harmonic reducer according to a specific embodiment of the present invention is schematically shown;

[0031] Figure 8 The figure schematically shows the cooperation between the finger and the dial according to a specific embodiment of the present invention.

[0032] The reference numerals are described as follows:

[0033] 1 motor, 2 housing, 2-1 fixed wheel, 3 housing cover, 4 wave generator assembly, 4-1 connecting frame, 4-2 roller, support shaft 4-3, 5 flexible wheel, 5-1 meshing part, 5-2 pusher claw, 6 output member, 6-1 dial, 6-11 pusher groove, 6-2 output shaft. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with specific embodiments. Please note that the embodiments described below are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention. If no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature in the art or the product instructions shall be followed.

[0035] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0036] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] The harmonic reducer and the driver of the present invention will be described in detail below through specific embodiments: Figure 1-8 As shown, the driver described in this embodiment includes a motor 1 and a harmonic reducer.

[0038] The specific structure of the harmonic reducer provided in this embodiment is as follows:

[0039] The harmonic reducer includes components such as a housing assembly, a wave generator assembly 4, a flexible wheel 5 and an output member 6. The housing assembly includes a housing 2 and a housing cover 3. The housing 2 is mounted on the output end of the motor 1 by screws. One end of the housing 2 is provided with a positioning hole adapted to the motor for easy assembly; the other end is provided with a connecting threaded hole. A fixed wheel 2-1 is also fixedly connected to the housing 2. Preferably, the fixed wheel 2-1 is connected to the housing 2 by an interference fit; and internal teeth are provided on the inner circumferential surface of the fixed wheel 2. The split arrangement of the housing 2 and the fixed wheel 2-1 reduces the difficulty of processing the fixed wheel 2-1 and reduces the cost.

[0040] The shell cover 3 is installed in the connecting threaded hole by screws to connect the shell cover 3 and the housing 2. A boss is provided on the outer end surface of the shell cover 3 to facilitate the positioning and installation of the harmonic reducer; a mounting threaded hole is also provided on the outer end surface for the installation and fixation of the harmonic reducer.

[0041] After the shell 2 and the shell cover 3 are connected, an installation cavity is formed inside. The wave generator assembly 4, the flexible wheel 5 and the output member 6 and other components are installed in the installation cavity. The wave generator assembly 4 includes a connecting frame 4-1, a roller 4-2 and a support shaft 4-3, and is arranged in the above-mentioned installation cavity as a whole. The wave generator assembly 4 is a double-contact vertical structure as a whole.

[0042] A motor shaft hole is provided at the center of the connecting frame 4-1, and the output shaft of the motor 1 is inserted into the motor shaft hole. A top screw hole is also provided on the connecting frame 1, and the connecting frame 1 is fixedly connected to the output shaft of the motor 1 through the top screw. A U-shaped opening is provided on both sides of the connecting frame 4-1, and a roller avoidance portion is provided between the two U-shaped openings. The support shaft 4-2 is installed in the installation holes provided on both sides of the connecting frame 4-1, and the roller 4-3 is provided in the middle of the support shaft 4-2, and the roller is preferably a standard bearing.

[0043] The flexible wheel 5 includes a meshing part 5-1 and a pusher claw 5-2. The meshing part 5-1 is a deformable cylindrical shape with a certain number of teeth on the outer circumference; the outer circumference of the meshing part 5-1 is provided with outer teeth extending along the axial direction and in a circumferential ring shape and evenly spaced, and the inner circumference of the meshing part 5-1 is a smooth surface.

[0044] A plurality of pusher claws 5-2 are evenly spaced and distributed on one end face of the meshing portion 5-1 in a circular distribution. Preferably, the pusher claw 5-2 is a cylinder. The meshing portion 5-1 and the pusher claw 5-2 can be manufactured as a whole, or they can be composited with different materials; the materials of the meshing portion 5-1 and the pusher claw 5-2 can be reasonably selected according to actual working conditions and needs. Preferably, the meshing portion 5-1 and the pusher claw 5-2 are composited with materials with different elasticities. The flexible wheel 5 of such a structure can overcome the defect of relatively low strength of the pusher claw 5-2 during the transmission process, forming a flexible wheel 5 with complementary elasticity and strength, which can improve the transmission efficiency and service life of the entire harmonic reducer.

[0045] The number of external teeth on the flexible wheel 5 is less than that of the internal teeth on the fixed wheel 2-1; the tooth shapes of the internal teeth and the external teeth are the same. Since the number of internal teeth on the fixed wheel 2-1 is greater than the number of external teeth on the flexible wheel 5, under normal conditions, when the two are coaxially arranged, the outer diameter of the flexible wheel 5 is smaller than the inner diameter of the fixed wheel 2-1, and the two do not contact. When the wave generator assembly 4 is installed in the fixed wheel 2-1, the wave generator assembly 4 squeezes the flexible wheel 5 to deform it into an elliptical shape, so that the external teeth of the elliptical flexible wheel 5 in the long axis direction are meshed with the internal teeth of the fixed wheel 2-1; there is a certain gap between the elliptical flexible wheel 5 and the fixed wheel 2-1 in the short axis direction; a two-point contact meshing state is formed between the flexible wheel 5 and the fixed wheel 2-1.

[0046] The output member 6 includes a dial 6-1 and an output shaft 6-2, and the dial 6-1 and the output shaft 6-2 can be an integral structure or a separate structure. The dial 6-1 is provided with the same number of shifting grooves 6-11 as the shifting claws 5-2, and the shifting grooves 6-11 are bar holes and are arranged along the radial direction of the dial, and the extension lines of the shifting grooves 6-11 converge at the central axis of the dial.

[0047] The pusher claw 5-2 is inserted into the push groove 6-11 to drive the dial 6-1 to rotate. The motion trajectory of each pusher claw 5-2 relative to the housing assembly is a small elliptical trajectory of the pusher claw 5-2 itself formed as the large elliptical rotational motion of the flexible wheel 5 relative to the dial 6. By setting the diameter of the cylinder of the pusher claw 5-2 and the width of the push groove 6-11, the different degrees of tightness of the two can be adjusted. Preferably, the push groove 6-11 is configured to match the shape of the pusher claw 5-2, that is, the diameter of the cylinder of the pusher claw 5-2 is the same as the width of the push groove 6-11.

[0048] The dial 6-1 is also provided with a bearing installation cavity and a motor shaft avoidance hole. The bearing in the bearing installation cavity is used to support the motor shaft and also provides support and positioning for the entire output member 6. The output shaft 6-2 is rotatably supported on the housing cover 3 through two output bearings 3-1 and extends out of the housing cover 3.

[0049] The working principles of the harmonic reducer and driver provided by the present invention are described in detail as follows:

[0050] In the harmonic reducer, the fixed wheel 2-1, the flexible wheel 5 and the output member 6 are coaxially arranged. The meshing portion 5-1 of the flexible wheel 5 is deformed into an elliptical shape under the support of the wave generator assembly 4, and is in contact and meshed with the fixed wheel 2-1 at two points. When the wave generator assembly 4 rotates continuously under the drive of the motor 1, the meshing point of the meshing portion 5-1 of the flexible wheel 5 and the fixed wheel 2-1 is also constantly changed. Since the number of teeth of the meshing portion 5-1 is less than the number of teeth of the fixed wheel 2-1, the flexible wheel 5 rotates relative to the fixed wheel 2-1 in the opposite direction of the rotation of the wave generator assembly 4. When the wave generator assembly 4 rotates one circle, the flexible wheel 5 rotates in the opposite direction by a certain angle.

[0051] Since the pusher claw 5-2 of the flexible wheel 5 is shaped to fit and can be slidably inserted into the push groove 6-11 of the dial 6-1 of the output member 6, when the meshing portion 5-1 is deformed into an ellipse, the pusher claw 5-2 slides radially relative to the push groove 6-11 under the actuation of the meshing portion 5-1, and the distribution of the pusher claw 5-2 also changes to an ellipse with the meshing portion 5-1. When the meshing point between the meshing portion 5-1 and the fixed wheel 2-1 is constantly changing, the pusher claw 5-2 continues to slide radially relative to the push groove 6-11 and deforms into a corresponding ellipse distribution state; at the same time, the pusher claw 5-2 rotates with the meshing portion 5-1 and actuates the dial 6-1 to rotate in the same direction and at the same angle. Therefore, the output member 6 obtains a reverse deceleration rotation output relative to the motor shaft.

[0052] During the transmission process, the finger 5-2 slides radially relative to the slot 6-11 along the dial 6-1. Since the finger 5-2 moves in a small elliptical trajectory relative to the housing assembly, the finger 5-2 squeezes the side wall of the slot 6-11 during the transmission process, generating corresponding deformation stress, so that the two are closely combined, thereby eliminating the transmission backlash.

[0053] The harmonic reducer provided in the present application includes a flexible wheel 5 having a meshing portion 5-1 and a pusher claw 5-2. During the harmonic reduction transmission process, since the pusher claw 5-2 can slide radially in the pusher groove, the flexible wheel 5 as a whole only presents a deformation rotation with an elliptical cross section, that is, only a two-dimensional deformation of the cylindrical surface is generated, and there will be no three-dimensional twisting deformation of the flexible wheel which is cylindrical as a whole. The two-dimensional deformation of the flexible wheel 5 during transmission in the present application reduces the internal stress during the transmission process, can protect the elasticity of the flexible wheel, and improve the service life of the harmonic reducer; at the same time, due to the reduction in deformation, the transmission efficiency is also improved.

[0054] The reduction ratio of industrial-grade harmonic reducers generally cannot be less than 35, because too small a reduction ratio will cause the flexible wheel to produce a large elliptical deformation, which seriously reduces the fatigue life of the flexible wheel. The structure with a pusher claw in the flexible wheel provided in this application allows the flexible wheel to withstand a relatively large elliptical deformation during the transmission process, so the reduction ratio of the harmonic reducer provided in this application can be less than 35, which is more suitable for the application in the field of lightweight service robots.

[0055] The flexible pulley structure provided by the present application can set the flexible pulley to have a sufficient thickness and will not cause too much change in internal stress, so it has a larger coupling range when designing the fatigue life of the flexible pulley, which is conducive to the design of improving the fatigue life. It is also conducive to the structural design of the fatigue life of the pusher claw and the extension of the service life of the flexible pulley.

[0056] The harmonic reducer provided in the present application has a separate arrangement of the housing and the stator, which reduces the difficulty of machining the internal teeth on the stator and reduces the cost; the flexible wheel is composed of a meshing part and a pusher claw, which has a simple structure, requires less material and reduces the cost.

[0057] In summary, the present invention provides a harmonic reducer and driver that have high transmission efficiency, long service life, large output torque and low cost, which has broad application prospects in the field of robotics.

[0058] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0059] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and assemble different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

Claims

1. A harmonic reducer, comprising a flexible wheel, a fixed wheel and an output member, characterized in that: The fixed wheel is provided with internal teeth, and the flexible wheel includes a meshing portion and a pusher claw; the meshing portion is cylindrical with external teeth; the external teeth and the internal teeth have the same tooth shape, and the number of teeth of the external teeth is less than the number of teeth of the internal teeth; After the meshing portion is actuated and deformed, the outer teeth and the inner teeth mesh; The pusher claw is arranged at one end of the meshing portion and is transmission-connected to the output member; The external teeth are teeth arranged on the outer circumferential surface of the meshing portion, extending along the axial direction and evenly spaced in a circumferential ring shape, and the inner circumferential surface of the meshing portion is a smooth surface; There are multiple push claws, which are evenly spaced and distributed in a circle; The output member includes a dial and an output shaft, the dial is provided with a shifting groove; the shifting claw is transmission-connected with the output member through the shifting groove; The shifting grooves are strip holes arranged along the radial direction of the dial, and the extension lines of the strip holes converge at the central axis of the dial; the number of the shifting grooves is the same as the number of the shifting claws.

2. The harmonic reducer according to claim 1, characterized in that: The pusher claw is a cylinder.

3. The harmonic reducer according to claim 2, characterized in that: It also includes a wave generator component, which actuates the meshing portion to deform so that the cross-section of the meshing portion changes from a circle to an ellipse; after the meshing portion is deformed, a certain gap exists between the outer teeth and the inner teeth in the major axis direction of the ellipse and between the outer teeth and the inner teeth in the minor axis direction.

4. The harmonic reducer according to claim 3, characterized in that: After the meshing portion is deformed, the plurality of pusher claws are distributed in the form of an ellipse.

5. The harmonic reducer according to claim 4, characterized in that: It also includes a shell assembly, which includes a shell and a shell cover; the shell and the shell cover are connected to form an installation cavity; the flexible wheel, the fixed wheel and the wave generator assembly are arranged in the installation cavity.

6. The harmonic reducer according to claim 5, characterized in that: During transmission, the pusher claw slides radially relative to the pusher groove along the dial; the movement trajectory of the pusher claw relative to the housing assembly is a small elliptical trajectory of the pusher claw itself formed by the large elliptical rotational movement of the flexible wheel relative to the dial.

7. A driver, comprising a motor and a harmonic reducer according to any one of claims 1 to 6, characterized in that: The harmonic reducer is installed at the output end of the motor.

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