High-precision zero-backlash humanoid robot joint speed reducer

Abstract

The invention provides a high-precision zero-backlash humanoid robot joint speed reducer, belongs to the technical field of speed reducers, and solves the technical problems that an existing humanoid robot is low in transmission precision, low in repeatable transmission precision and the like. When the speed reducer is used, the bevel gear sun gear is connected with an external power transmission mechanism, so that power is obtained, the bevel gear sun gear rotates to drive the bevel gear planet gears to rotate and revolve around the bevel gear sun gear at the same time, the bevel gear planet gears rotate to drive the planet carrier to rotate at the same time, and first-stage planetary transmission speed reduction is achieved. A gear of a common planetary reducer is changed into a bevel gear, the transmission efficiency and the bearing capacity of the bevel gear are greatly improved compared with those of a harmonic reducer, meanwhile, an elastic piece is additionally arranged on a shaft of a bevel gear planet wheel or the bevel gear planet wheel is loaded on a planet carrier in an axial positioning and pressing mode, and therefore the backlash is adjusted; the transmission precision and the repeatable transmission precision of the speed reducer can be improved, and in addition, the bevel gears are good in machining manufacturability and low in price.

Description

Technical Field

[0001] This invention belongs to the field of speed reducer technology, and relates to a humanoid robot joint speed reducer, particularly a high-precision zero-backlash humanoid robot joint speed reducer. Background Technology

[0002] Currently, harmonic reducers are commonly used joint reducers in humanoid robots. However, the application of harmonic reducers in humanoid robots has some drawbacks: First, the transmission efficiency of harmonic reducers is only 50%-60%, resulting in the loss of most of the energy during operation, which cannot meet the power transmission efficiency requirements of humanoid robots. Second, because harmonic reducers operate without backlash, the friction and wear during operation are significant, leading to a shorter lifespan. Third, repeatability cannot be guaranteed; after a period of operation, the operating accuracy decreases, failing to meet the repeatability requirements of humanoid robots. Finally, harmonic reducers are relatively expensive and require advanced manufacturing processes. Summary of the Invention

[0003] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a high-precision zero-backlash humanoid robot joint reducer. The technical problem this invention aims to solve is: how to achieve high-precision zero-backlash transmission during humanoid robot joint movements.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A high-precision, zero-backlash humanoid robot joint reducer includes a housing. The housing is characterized by being a hollow, rotating cavity structure with an input end and an output end at its two ends. Inside the housing, from the input end to the output end, are sequentially arranged a sun gear, planet gears, a planet carrier, and an internal gear ring. A bearing is fitted onto the inner wall of the housing near the input end. The planet carrier is divided into a left side and a right side, opposite to each other. The left side of the planet carrier is fitted inside the bearing and abuts against the inner ring of the bearing. The internal gear ring is fitted onto the inner wall of the housing and located on the inner ring of the bearing. Between the end face and the inner cavity end face of the housing, the two ends of the sun gear are respectively fitted onto the center of the left side and the right side of the planetary carrier. The two sides of the toothed part of the sun gear are respectively abutted against the left side and the right side of the planetary carrier by bearing three. At least two planet gears are distributed in a ring between the left side and the right side of the planetary carrier. The two ends of each planet gear are respectively fitted onto the left side and the right side of the planetary carrier by bearing two. Each planet gear meshes with the internal gear ring and the sun gear at the same time. Each planet gear is loaded on the planetary carrier by axial preload.

[0006] The sun gear, planet gears, and internal gear ring are all bevel gears, and the direction of their taper inclination is consistent.

[0007] The taper of the sun gear, planet gears, and internal gear ring is 2-4°, and the angle between the central axis of the planet gear and the sun gear is 6-8°.

[0008] The sun gear and planet gears, as well as the planet gears and internal gear ring, are engaged at their large ends.

[0009] The planet carrier, sun gear, and internal gear ring are arranged coaxially.

[0010] Each planetary gear has an elastic element fitted between one end and the bearing on one side of the planet carrier, providing tight contact between the two. The elastic element is a leaf spring.

[0011] One end of each planetary gear is mounted on the planet carrier by axial positioning and clamping, while maintaining tight meshing with the sun gear and the internal gear ring.

[0012] By adopting the above structure, the planetary gears are mounted on the planetary carrier by setting elastic elements on the planetary gear shaft or by axial positioning and clamping, achieving zero backlash meshing between the planetary gears, the sun gear, and the internal gear ring.

[0013] The working principle of this invention is as follows: After the reducer is assembled, the sun gear of the bevel gear is connected to the external power transmission mechanism through the input end of the housing to obtain power. Then, the sun gear of the bevel gear rotates, simultaneously driving each bevel gear planet gear to rotate synchronously. Each bevel gear planet gear meshes with the bevel gear internal gear ring to achieve its own rotation, and each bevel gear planet gear revolves synchronously around the sun gear of the bevel gear. Simultaneously, the rotation of each bevel gear planet gear drives the planet carrier to rotate, achieving a single-stage planetary transmission reduction. Then, the planet carrier connects the reduced power to the external transmission mechanism through the output end of the housing to achieve power output. In the invention, the reducer uses bevel gears for both deceleration and power transmission, with a taper of 2-4° for the sun gear, planet gears, and internal gear ring. This results in an angle of 6-8° between the central axes of the planet gears and the sun gear. The planet gears mesh with the sun gear and internal gear ring at their large ends. While achieving high load-bearing meshing at the large ends, leaf springs are installed between the ends of the planet gear teeth and the planet carrier, or they are mounted on the planet carrier by axial positioning and clamping. Due to the elasticity of the leaf springs or the axial preload, the planet gears always maintain a tight meshing at their large ends with the sun gear and internal gear ring during transmission.

[0014] This invention replaces the gears of a conventional planetary reducer with bevel gears, which significantly improves the transmission efficiency and load-bearing capacity compared to harmonic reducers. At the same time, elastic elements are added to the shafts of the bevel gear planetary gears or they are mounted on the planetary carrier by axial positioning and clamping to adjust the backlash, thereby improving the transmission accuracy and repeatability of the reducer. In addition, bevel gears are easy to process and inexpensive.

[0015] This invention creatively uses small-module bevel gears in a humanoid robot joint reducer and specially developed and designed taper and included angle. It also loads leaf springs at the ends of the bevel gear planetary gear teeth or loads them on the planetary carrier by axial positioning and clamping. By adjusting the axial displacement of the bevel gear planetary gear, the backlash between the gear teeth is reduced, thereby achieving zero backlash transmission, which has high transmission accuracy and high repeatability.

[0016] At least two inclined cylindrical structures with open ends and internal passages are distributed in a ring along the central axis on the left side end face of the planetary carrier. The central axes of each cylindrical structure intersect at a point located on the central axis of the left side of the planetary carrier.

[0017] At least two inclined cylindrical structures II with open ends and internal passages are distributed in a ring along the central axis on the right side end face of the planetary carrier. The central axes of each cylindrical structure II intersect at a point located on the central axis of the right side of the planetary carrier.

[0018] The first cylindrical structure and the second cylindrical structure are coaxially arranged and tilt in the same direction. The two ends of the planetary gear are respectively sleeved in the first cylindrical structure and the second cylindrical structure through the second bearing. The planetary gear is coaxial with the first cylindrical structure and the second cylindrical structure.

[0019] Compared with existing technologies, this high-precision zero-backlash humanoid robot joint reducer has the following advantages:

[0020] 1. After the reducer of the present invention is assembled, the sun gear of the bevel gear is connected to the external power transmission mechanism through the input end of the housing to obtain power. Then, the sun gear of the bevel gear rotates, which drives the planetary gears of each bevel gear to rotate synchronously. Each planetary gear of the bevel gear meshes with the bevel gear internal gear ring to achieve rotation. Each planetary gear of the bevel gear revolves synchronously around the sun gear of the bevel gear. While each planetary gear of the bevel gear rotates, it drives the planet carrier to rotate, realizing the first-stage planetary transmission reduction. Then, the planet carrier connects the reduced power to the external transmission mechanism through the output end of the housing to realize power output.

[0021] 2. This invention replaces the gears of a conventional planetary reducer with bevel gears, which significantly improves the transmission efficiency and load-bearing capacity compared to harmonic reducers. At the same time, elastic elements are added to the shafts of the bevel gear planetary gears or they are mounted on the planetary carrier by axial positioning and clamping to adjust the backlash, thereby improving the transmission accuracy and repeatability of the reducer. In addition, bevel gears are easy to process and inexpensive.

[0022] 3. This invention creatively uses small-module bevel gears in the humanoid robot joint reducer and specially developed and designed taper and included angle. It also loads leaf springs at the ends of the bevel gear planetary gear teeth or loads them on the planetary carrier by axial positioning and clamping. By adjusting the axial displacement of the bevel gear planetary gear, the backlash between the gear teeth is reduced, thereby achieving zero backlash transmission, which has high transmission accuracy and high repeatability. Attached Figure Description

[0023] Figure 1 This is a perspective view of the assembly of Embodiment 1 of the present invention.

[0024] Figure 2 This is the overall assembly plan view of Embodiment 1 of the present invention.

[0025] Figure 3 yes Figure 2 AA section view.

[0026] Figure 4 This is a three-dimensional structural diagram of the meshing of the planetary gear and the sun gear in Embodiment 1 of the present invention.

[0027] Figure 5 This is a schematic diagram of the planar structure of the meshing planetary gear and sun gear in Embodiment 1 of the present invention.

[0028] Figure 6 This is a perspective view of the casing in Embodiment 1 of the present invention.

[0029] Figure 7 This is a perspective view of the planetary support in Embodiment 1 of the present invention.

[0030] Figure 8 This is a perspective view of planetary support 2 in Embodiment 1 of the present invention.

[0031] Figure 9 This is a perspective view of the internal gear ring in Embodiment 1 of the present invention.

[0032] Figure 10 This is a perspective view of the planetary gear in Embodiment 1 of the present invention.

[0033] Figure 11 This is a perspective view of the sun gear in Embodiment 1 of the present invention.

[0034] Figure 12 This is a perspective view of the leaf spring in Embodiment 1 of the present invention.

[0035] Figure 13 This is an assembly effect diagram of Embodiment 1 of the present invention.

[0036] Figure 14 This is an exploded view of Embodiment 1 of the present invention.

[0037] Figure 15This is a schematic diagram of the transmission system according to Embodiment 1 of the present invention.

[0038] Figure 16 This is a schematic diagram of the transmission system according to Embodiment 2 of the present invention.

[0039] In the diagram, 1. Housing; 2. Planetary carrier; 2a. Left side of planetary carrier; 2b. Right side of planetary carrier; 3. Planetary gear; 4. Sun gear; 5. Internal gear ring; 6. Leaf spring; 7. Bearing 1; 8. Bearing 2; 9. Bearing 3. Detailed Implementation

[0040] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0041] Example 1:

[0042] like Figures 1-15 As shown, this embodiment provides a high-precision, zero-backlash humanoid robot joint reducer, including a housing 1. The housing 1 is a hollow, rotating cavity structure that can be used to install a motor. The motor is fixed on the housing 1, resulting in a compact structure. The two ends of the housing 1 are the input end and the output end, respectively. Inside the housing 1, from the input end to the output end, a sun gear 4, planet gears 3, a planet carrier 2, and an internal gear ring 5 are arranged sequentially. A bearing 7 is fitted on the inner wall of the housing 1 near the input end. The planet carrier 2 is divided into a left side and a right side, which are arranged opposite each other. The left side 2a of the planet carrier is fitted inside the bearing 7 and abuts against the inner ring of the bearing 7. The internal gear ring 5 is fitted on the inner wall of the housing 1. The sun gear 4 is located between the end face of bearing 7 and the inner cavity end face of housing 1. The two ends of the sun gear 4 are respectively sleeved on the center of the left side 2a and the right side 2b of the planetary carrier. The toothed part of the sun gear 4 is abutted against the left side 2a and the right side 2b of the planetary carrier by bearing 9. At least two planet gears 3 are distributed in a ring between the left side 2a and the right side 2b of the planetary carrier. The two ends of each planet gear 3 are respectively sleeved on the left side 2a and the right side 2b of the planetary carrier by bearing 8. Each planet gear 3 is simultaneously meshed with the internal gear ring 5 and the sun gear 4. Each planet gear 3 is loaded on the planetary carrier 2 by axial preload.

[0043] Sun gear 4, planet gear 3, and internal gear ring 5 are all bevel gears with the same taper inclination direction; the taper of sun gear 4, planet gear 3, and internal gear ring 5 is 3°, and the angle between the central axes of planet gear 3 and sun gear 4 is 6°; sun gear 4 and planet gear 3, and planet gear 3 and internal gear ring 5 are all engaged at their large ends; planet carrier 2, sun gear 4, and internal gear ring 5 are coaxially arranged; through the above structural arrangement, planet gear 3 can mesh with sun gear 4 and internal gear ring 5 with zero backlash, while achieving a compact structure and high transmission accuracy.

[0044] Each planetary gear 3 has a leaf spring 6 fitted between its right end and the bearing 8 on the right side of the planetary carrier 2b. The right end of each planetary gear 3 is mounted on the right side of the planetary carrier 2b by axial positioning and clamping, while maintaining tight meshing with the sun gear 4 and the internal gear ring 5. By setting the elastic element on the planetary gear 3 shaft or mounting it on the planetary carrier 2 by axial positioning and clamping, either of these methods can achieve zero backlash meshing between the planetary gear 3 and the sun gear 4 and the internal gear ring 5.

[0045] The working principle of this invention is as follows: After the reducer is assembled, the bevel gear sun gear 4 is connected to an external motor through the input end of the housing 1 to obtain power. Then, the bevel gear sun gear 4 rotates, simultaneously driving each bevel gear planet gear 3 to rotate synchronously. Each bevel gear planet gear 3 meshes with the bevel gear internal gear ring 5 to achieve its own rotation, and each bevel gear planet gear 3 revolves synchronously around the bevel gear sun gear 4. The rotation of each bevel gear planet gear 3 simultaneously drives the planet carrier 2 to rotate, realizing a single-stage planetary transmission reduction. Then, the planet carrier 2 connects the reduced power to an external transmission mechanism through the output end of the housing 1 to realize power output. In the reducer, the sun gear 4, planet gear 3, and internal gear ring 5 are all bevel gears with a taper of 3°. This results in a 6° angle between the central axes of planet gear 3 and sun gear 4. Planet gear 3 is engaged with sun gear 4 and internal gear ring 5 at the large end. While achieving high load-bearing engagement at the large end, leaf springs 6 are installed between the tooth ends of planet gear 3 and planet carrier 2, or are mounted on planet carrier 2 by axial positioning and clamping. Due to the elasticity of leaf springs 6 or axial preload, planet gear 3 always maintains a tight large-end engagement with sun gear 4 and internal gear ring 5 during transmission.

[0046] This invention replaces the gears of a conventional planetary reducer with bevel gears, which significantly improves the transmission efficiency and load-bearing capacity compared to harmonic reducers. At the same time, elastic elements are added to the shaft of the bevel gear planetary gear 3 or it is mounted on the planet carrier 2 by means of axial positioning and clamping to adjust the backlash, which can improve the transmission accuracy and repeatability of the reducer. In addition, bevel gears have good machinability and are inexpensive.

[0047] This invention creatively uses small-module bevel gears in a humanoid robot joint reducer and specially developed and designed taper and included angle. It also loads leaf springs 6 at the tooth ends of the bevel gear planetary gear 3 or loads them on the planet carrier 2 by means of axial positioning and clamping. By adjusting the axial displacement of the bevel gear planetary gear 3, the backlash between the gear teeth is reduced, thereby achieving zero backlash transmission, which has high transmission accuracy and high repeatability.

[0048] At least two inclined cylindrical structures, open at both ends and internally connected, are arranged in a ring along the central axis on the left side 2a end face of the planetary carrier. The central axes of each cylindrical structure intersect at a point located on the central axis of the left side 2a of the planetary carrier. At least two inclined cylindrical structures, open at both ends and internally connected, are arranged in a ring along the central axis on the right side 2b end face of the planetary carrier. The central axes of each cylindrical structure intersect at a point located on the central axis of the right side 2b of the planetary carrier. The cylindrical structures are coaxial and inclined in the same direction. The two ends of the planetary gear 3 are respectively sleeved in the cylindrical structures 1 and 2 through bearings 2 and 8. The planetary gear 3 is coaxial with the cylindrical structures 1 and 2.

[0049] Using the above structure, the left side 2a and the right side 2b of the planetary carrier together constitute the main structure of the planetary carrier 2, realizing the transmission of the planetary gear 3 and the sun gear 4 at a specific angle between their central axes.

[0050] In this embodiment, planetary gears 3 are three identical gear shafts arranged in a ring around the central axis of sun gear 4. Sun gear 4 is also a gear shaft. There are six bearings each (bearing 2, 8 and 9), and they are arranged in pairs facing each other. The taper of sun gear 4, planetary gears 3, and internal gear ring 5 is 3°, and the angle between the central axes of planetary gears 3 and sun gear 4 is 6°. These can all be achieved through machining and assembly precision. Slight deviations do not affect the technical implementation of this invention and are all within a controllable range. The central axes of the three planetary gears 3 intersect on the central axis of sun gear 4, and the intersection point is located at the input end. See details below. Figure 15 .

[0051] Example 2:

[0052] The difference between this embodiment and Embodiment 1 lies in the different taper inclination directions of the sun gear 4, planet gears 3, and internal gear ring 5. In this embodiment, the central axes of all three planet gears 3 intersect on the central axis of the sun gear 4, and the intersection point is located at the output end. See details below. Figure 16 Furthermore, the structure of other components that adapt to different orientations can be easily achieved using the technical solution of this invention, without requiring creative effort, and all are within the protection scope of this invention.

[0053] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A high-precision, zero-backlash humanoid robot joint reducer, comprising a housing, characterized in that, The housing is a hollow rotating cavity structure with an input end and an output end at its two ends. Inside the housing, from the input end to the output end, there are a sun gear, planet gears, a planet carrier, and an internal gear ring arranged sequentially. A bearing is fitted on the inner wall of the housing near the input end. The planet carrier is divided into a left side and a right side, which are arranged opposite each other. The left side of the planet carrier is fitted inside the bearing and abuts against the inner ring of the bearing. The internal gear ring is fitted on the inner wall of the housing and is located between the end face of the bearing and the end face of the inner cavity of the housing. The two ends of the sun gear are fitted on the center of the left side and the right side of the planet carrier, respectively. The toothed part of the sun gear abuts against the left side and the right side of the planet carrier through bearings three, respectively. At least two planet gears are arranged in a ring between the left side and the right side of the planet carrier. The two ends of each planet gear are fitted on the left side and the right side of the planet carrier through bearings two, respectively. Each planet gear meshes with the internal gear ring and the sun gear simultaneously. Each planet gear is loaded on the planet carrier by axial preload.

2. The high-precision zero-backlash humanoid robot joint reducer according to claim 1, characterized in that, The sun gear, planet gears, and internal gear ring are all bevel gears, and the direction of their taper inclination is consistent.

3. The high-precision zero-backlash humanoid robot joint reducer according to claim 1, characterized in that, The taper of the sun gear, planet gears, and internal gear ring is 2-4°, and the angle between the central axis of the planet gear and the sun gear is 6-8°.

4. The high-precision zero-backlash humanoid robot joint reducer according to claim 1, characterized in that, The sun gear and planet gears, as well as the planet gears and internal gear ring, are engaged at their large ends.

5. The high-precision zero-backlash humanoid robot joint reducer according to claim 1, characterized in that, The planet carrier, sun gear, and internal gear ring are arranged coaxially.

6. The high-precision zero-backlash humanoid robot joint reducer according to claim 1, characterized in that, Each planetary gear has an elastic element fitted between one end of the planetary gear and the bearing on one side of the planetary carrier, which fits tightly against both.

7. The high-precision zero-backlash humanoid robot joint reducer according to claim 1, characterized in that, One end of each planetary gear is mounted on the planet carrier by axial positioning and clamping, while maintaining tight meshing with the sun gear and the internal gear ring.

8. The high-precision zero-backlash humanoid robot joint reducer according to claim 1, characterized in that, At least two inclined cylindrical structures with open ends and internal passages are distributed in a ring along the central axis on the left side end face of the planetary carrier. The central axes of each cylindrical structure intersect at a point located on the central axis of the left side of the planetary carrier.

9. The high-precision zero-backlash humanoid robot joint reducer according to claim 1, characterized in that, At least two inclined cylindrical structures II with open ends and internal passages are distributed in a ring along the central axis on the right side end face of the planetary carrier. The central axes of each cylindrical structure II intersect at a point located on the central axis of the right side of the planetary carrier.

10. The high-precision zero-backlash humanoid robot joint reducer according to claim 1, characterized in that, The first cylindrical structure and the second cylindrical structure are coaxially arranged and tilt in the same direction. The two ends of the planetary gear are respectively sleeved in the first cylindrical structure and the second cylindrical structure through the second bearing. The planetary gear is coaxial with the first cylindrical structure and the second cylindrical structure.

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