Lightweight harmonic speed reducer

Abstract

The invention provides a lightweight harmonic speed reducer, and relates to the technical field of speed reducers. A flexible gear is respectively connected with a wave generator and an inner structural body of a crossed roller bearing through an elastic meshing interface; an inner gear matched with the flexible gear in tooth shape is arranged on the inner side of the inner structure body. The invention has the beneficial effects that the internal gear and the crossed roller bearing are integrally designed, so that the number of assembly components is reduced, the volume of parts is reduced, the axial size is reduced, the structural rigidity is improved, the stress distribution of a transmission interface is more uniform, the service life is effectively prolonged, and the assembly difficulty is reduced; the crossed roller bearing is made of a polymer composite material, and the weight of the crossed roller bearing is reduced by 30-50% compared with that of a traditional metal material, so that the weight of the harmonic speed reducer can be greatly reduced, the burden of a driving motor is reduced, the service life of the driving motor is prolonged, the elasticity is increased due to the design of the axial hollow roller, and the precision error and the assembly error of parts can be absorbed; and a gap between the roller and the track is eliminated through elastic deformation, so that transmission without a back gap is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of speed reducers, and particularly to a lightweight harmonic speed reducer. Background Art

[0002] A harmonic reducer is a high-precision transmission device based on the principle of elastic deformation. Its core structure consists of a rigid gear, a flexible gear, and a wave generator. The rigid gear, as a rigid internal gear, forms a meshing basis with the external gear of the flexible gear made of high-strength thin-wall alloy material with a tooth number difference (usually 2 teeth). The wave generator, as a power input mechanism, drives the flexible gear to generate periodic elastic deformation through the coordinated action of an elliptical cam and a flexible bearing, realizes the dynamic adjustment of the tooth surface contact area, and thus completes the transmission with a high reduction ratio (up to more than 100:1). Its transmission error can be controlled within 1 arc minute, and at the same time, it has a transmission efficiency of more than 90%, meeting the industrial requirements of high precision and low energy consumption.

[0003] At the application level, the harmonic reducer has become the preferred transmission solution for load scenarios below 20 kg due to its compact structure and lightweight characteristics. It performs outstandingly especially in the wrist and elbow joints of industrial robots and SCARA robots. Its application fields have extended to high-end fields such as aerospace (satellite attitude adjustment), medical equipment (precision drive of surgical robots), and semiconductor manufacturing (wafer positioning systems), demonstrating its multi-scenario adaptability.

[0004] In the engineering practice of harmonic reducers, lightweight design is the key technical path to reduce the inertial load of the system and improve the dynamic response ability. By optimizing the mass distribution of the transmission system, the energy consumption of motor drive can be significantly reduced and the movement flexibility of the equipment can be enhanced.

[0005] The technical content disclosed in the Chinese patent document (publication number: CN105840766A, patent name: A lightweight harmonic speed reducer) is as follows: It includes a wave generator, a rigid gear, a four-point contact bearing, a flexible gear, a bearing bracket, and a load plate. The wave generator is arranged in the flexible gear, the flexible gear meshes in the rigid gear, the four-point contact bearing is arranged between the bearing bracket and the load plate, the rigid gear is fixed to the bearing bracket on the outer ring side of the four-point contact bearing, and the flexible gear is fixed to the load plate on the inner ring side of the four-point contact bearing.

[0006] It can be seen from the above implementation scheme and the corresponding drawings that this lightweight harmonic speed reducer reduces weight through the layout of a four-point contact bearing with a simplified structure. However, limited by the inherent density of metal materials, the overall weight reduction effect is limited, so it is difficult to truly reduce the energy consumption of the motor. Summary of the Invention

[0007] The present invention overcomes the shortcomings in the prior art and provides a lightweight harmonic reducer. Its internal gear and crossed roller bearing are integrally designed, significantly reducing the number of assembly components, shrinking the volume of components, reducing the axial dimension and enhancing the structural rigidity. This design makes the stress distribution at the transmission interface more uniform, effectively extending the service life of components, reducing the assembly difficulty. Moreover, the crossed roller bearing is made of a high molecular composite material, which reduces the weight by 30%-50% compared with traditional metal materials. Therefore, it can greatly reduce the weight of the harmonic reducer, making the harmonic reducer lighter when in use, thus reducing the burden on the driving motor and extending the service life of the driving motor. In addition, the axially hollow roller design increases the elasticity, can absorb the precision errors and assembly errors of parts, and eliminates the clearance between the rollers and the track through its elastic deformation, achieving backlash-free transmission.

[0008] To solve the above technical problems, the present invention is realized through the following technical solutions: A lightweight harmonic reducer includes a flexspline, and the flexspline is respectively connected to a wave generator and the inner structure of a crossed roller bearing through an elastic meshing interface; An internal gear matching the tooth profile of the flexspline is provided inside the inner structure; The crossed roller bearing is further provided with an outer ring structure linked to the inner structure, and all the crossed roller bearings are made of a high molecular composite material.

[0009] Furthermore, the crossed roller bearing includes rollers arranged crosswise, and each roller is provided with an axially penetrating hollow weight-reducing cavity, and the roller can undergo elastic deformation when being extruded.

[0010] Furthermore, the roller is provided with an axially penetrating hollow weight-reducing cavity, and an elastic deformation amount of 0.05-0.1 mm is allowed within the rated load range. This axially hollow roller design increases the elasticity, can absorb the precision errors and assembly errors of parts, and eliminates the clearance between the rollers and the track through its elastic deformation, achieving backlash-free transmission.

[0011] Furthermore, the outer ring structure includes a first outer ring and a second outer ring, and the first outer ring and the second outer ring wrap one side of the rollers; An inner ring is provided on the side of the inner structure facing away from the internal gear, and the inner ring wraps the side of the roller away from the outer ring structure.

[0012] Furthermore, a dynamic clearance compensation area is formed between the first outer ring, the second outer ring and the inner ring through the elastic structure of the rollers.

[0013] Furthermore, the first outer ring, the second outer ring, the inner structure and the rollers are all made of PEEK material or resin material, and the arrangement direction of the rollers forms an angle of 45°±0.1° with the axial direction of the bearing.

[0014] Furthermore, a sealing ring is provided between the first outer ring and the inner structure.

[0015] Furthermore, the wave generator includes a cam, the cam is connected to the flexspline bearing, and the flexspline bearing is sleeved at the center of the flexspline.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The integrated design of its internal gear and crossed roller bearing significantly reduces the number of assembly components, reduces the volume of components, reduces the axial dimension and improves the structural rigidity. This design makes the stress distribution at the transmission interface more uniform, effectively extends the service life of the components, and reduces the assembly difficulty.

[0017] 2. The crossed roller bearing is made of high molecular composite material, which reduces the weight by 30%-50% compared with traditional metal materials. Therefore, it can greatly reduce the weight of the harmonic reducer, making the harmonic reducer lighter when in use, thus reducing the burden on the driving motor and extending the service life of the driving motor. Description of the Drawings

[0018] The drawings are used to provide a further understanding of the present invention, and together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the drawings: Figure 1 is the overall structural schematic diagram of the harmonic reducer according to the embodiment of the present invention; Figure 2 is the sectional view of the harmonic reducer according to the embodiment of the present invention; Figure 3 is the exploded view of the harmonic reducer according to the embodiment of the present invention; Figure 4 is the half-sectional view of the harmonic reducer according to the embodiment of the present invention.

[0019] In the figure: 1. Flexspline; 101. Flexspline disk; 102. Flexspline teeth; 2. Crossed roller bearing; 201. Roller; 202. First outer ring; 203. Second outer ring; 204. Inner structure; 2041. Internal gear teeth; 2042. Inner ring; 3. Sealing ring; 4. Wave generator; 401. Cam; 402. Flexspline bearing. Detailed Embodiments

[0020] The following describes the preferred embodiments of the present invention with reference to the drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0021] As Figures 1 to 4As shown in the figure, a lightweight harmonic reducer includes a flexible gear 1, and the flexible gear 1 is respectively connected to a wave generator 4 and an inner structure 204 of a crossed roller bearing 2 through an elastic meshing interface; an internal gear 2041 matching the tooth profile of the flexible gear 1 is provided inside the inner structure 204; in the present invention, by integrally designing the internal gear and the crossed roller bearing, the number of assembly components is significantly reduced, the volume of components is reduced, the axial dimension is reduced, and the structural rigidity is improved. This design makes the stress distribution at the transmission interface more uniform, effectively extends the service life of the components, and reduces the assembly difficulty.

[0022] The wave generator 4 includes a cam 401, and the cam 401 is connected to a flexible gear bearing 402, and the flexible gear bearing 402 is sleeved at the center of the flexible gear 1. The flexible gear 1 includes annular flexible gear teeth 102, and a flexible gear disk 101 extends outward from one end of the flexible gear teeth 102.

[0023] The crossed roller bearing 2 is also provided with an outer ring structure linked to the inner structure 204. The crossed roller bearing 2 is made of a high molecular composite material, and compared with traditional metal materials, the weight is reduced by 30%-50%. Therefore, the weight of the harmonic reducer can be greatly reduced, making the harmonic reducer lighter when in use, thus reducing the burden on the driving motor and extending the service life of the driving motor.

[0024] The crossed roller bearing 2 includes crossed rollers 201. Each roller 201 is provided with an axially penetrating hollow weight-reducing cavity. The roller 201 can undergo elastic deformation when being extruded. The hollow weight-reducing cavity has both the functions of weight reduction and elastic deformation buffering, and also enables the roller 201 to absorb part of the errors caused by part precision and dynamic loads during application. Therefore, the manufacturing cost of parts can be reduced. The roller 201 can also eliminate the gap between the roller 201 and the running track through elastic deformation, thereby achieving gapless transmission, improving the transmission precision, and reducing the vibration generated due to the gap during the transmission process, so that each component of the reducer can still maintain a tight connection after a long running time.

[0025] In this embodiment, the roller 201 is provided with an axially penetrating hollow weight-reducing cavity, allowing an elastic deformation amount of 0.05 - 0.1 mm within the rated load range, reducing the friction coefficient and inhibiting plastic deformation.

[0026] The outer ring structure includes a first outer ring 202 and a second outer ring 203. The first outer ring 202 and the second outer ring 203 wrap one side of the roller 201; an inner ring 2042 is provided on the side of the inner structure 204 facing away from the internal gear 2041, and the inner ring 2042 wraps the side of the roller 201 away from the outer ring structure; a dynamic gap compensation area is formed between the first outer ring 202, the second outer ring 203 and the inner ring 2042 through the elastic structure of the roller. Therefore, when the harmonic reducer vibrates, the crossed ball bearing 2 can absorb the vibration through the dynamic gap compensation area, improving the vibration absorption ability.

[0027] In this embodiment, the first outer ring 202, the second outer ring 203, the inner structure 204 and the rollers 201 are all made of PEEK (polyether ether ketone composite) material or resin material. The arrangement direction of the rollers 201 forms an angle of 45°±0.1° with the axial direction of the bearing. Through anisotropic mechanical design, the optimization matching of axial load bearing and radial deformation is realized, ensuring the elastic compensation ability under high rigidity conditions.

[0028] A sealing ring 3 is arranged between the first outer ring 202 and the inner structure 204. The sealing ring 3 can ensure that the grease is retained inside the crossed roller bearing 2 and can also prevent impurities such as dust from entering the crossed roller bearing 2, thus enabling the smooth operation of the rollers 201.

[0029] Through structural integration, material compounding and mechanical optimization design, the present invention reduces the axial dimension of the harmonic reducer by 15%-20%, reduces the overall mass by 25%-40%, while maintaining the transmission accuracy within 60 arc seconds. The dynamic clearance compensation mechanism reduces the vibration of the components to 2-3 times that of the traditional design, which is particularly suitable for the humanoid robot scenario where space and weight are limited and vibration needs to be suppressed.

[0030] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. However, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A lightweight harmonic reducer, characterized in that: The flexible wheel (1) is connected to a wave generator (4) and an inner structure (204) of a cross roller bearing (2) through an elastic meshing interface. An internal gear (2041) matching the tooth shape of the flex spline (1) is provided on the inner side of the inner structure (204); The cross roller bearing (2) is also provided with an outer ring structure linked to the inner structure (204); the cross roller bearing (2) is made of polymer composite materials.

2. The lightweight harmonic reducer according to claim 1, characterized in that: The cross roller bearing (2) comprises cross-arranged rollers (201), each roller (201) being provided with an axially penetrating hollow weight-reducing cavity, and the roller (201) can be elastically deformed when squeezed.

3. The lightweight harmonic reducer according to claim 2, characterized in that: The roller (201) is provided with an axially penetrating hollow weight-reducing cavity, which allows an elastic deformation of 0.05-0.1 mm within the rated load range; this axially hollow roller design increases elasticity, can absorb part precision errors and assembly errors, and eliminate the gap between the roller and the track through its elastic deformation, thereby achieving backlash-free transmission.

4. The lightweight harmonic reducer according to claim 3, characterized in that: The outer ring structure comprises a first outer ring (202) and a second outer ring (203), wherein the first outer ring (202) and the second outer ring (203) wrap around a side surface of the roller (201); An inner ring (2042) is provided on the side of the inner structure (204) facing away from the inner gear (2041), and the inner ring (2042) wraps around the side of the roller (201) away from the outer ring structure.

5. The lightweight harmonic reducer according to claim 4, characterized in that: A dynamic clearance compensation zone is formed between the first outer ring (202), the second outer ring (203) and the inner ring (2042) through the elastic structure of the roller.

6. The lightweight harmonic reducer according to claim 5, characterized in that: The first outer ring (202), the second outer ring (203), the inner structure (204) and the rollers (201) are all made of PEEK material or resin material, wherein the cross-arrangement direction of the rollers (201) forms an angle of 45°±0.1° with the axial direction of the bearing.

7. The lightweight harmonic reducer according to claim 6, characterized in that: A sealing ring (3) is provided between the first outer ring (202) and the inner structure (204).

8. The lightweight harmonic reducer according to any one of claims 1 to 7, characterized in that: The wave generator (4) comprises a cam (401), the cam (401) is connected to a flexspline bearing (402), and the flexspline bearing (402) is sleeved at the center of the flexspline (1).

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