High-precision zero-backlash NW planetary reducer

Abstract

The invention provides a high-precision zero-backlash NW planetary reducer, belongs to the technical field of reducers, and solves the technical problems that the reduction ratio range of an existing humanoid robot is small and the like. When the speed reducer is used, the bevel gear sun gear is driven by an external power source to obtain power, then the bevel gear sun gear drives the first bevel gear planet gears to rotate synchronously, and the first bevel gear planet gears start to rotate after obtaining power subjected to primary speed reduction; the power after primary speed reduction is synchronously transmitted to each bevel gear planet gear II through a gear connecting shaft, and at the moment, each bevel gear planet gear revolves around a bevel gear sun gear while rotating and drives a planet carrier to rotate, so that secondary planetary transmission speed reduction is realized; according to the speed reducer, two stages of bevel gear planet gears are located on the same shaft during speed reduction, the number of teeth of the first stage is larger than that of teeth of the second stage, the directions of the large ends and the small ends of the two stages are opposite, and the effects of offsetting axial force and achieving zero backlash or small backlash while the transmission ratio is high are achieved.

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 NW planetary 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.

[0003] In addition, compared with the invention patent filed by the applicant prior to this application [Application No.: 2023116056665; Invention Title: High-Precision Zero Backlash Humanoid Robot Joint Reducer], the following improvements have been made: This application improves upon the prior application's small conical planetary gear reducer, which has a relatively small reduction ratio and insufficient ability to handle application scenarios with high reduction ratios. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a high-precision, zero-backlash NW planetary reducer. The technical problem this invention aims to solve is: how to achieve a wider range of transmission ratios in the transmission of humanoid robot joint reducers.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A high-precision, zero-backlash NW planetary reducer, comprising a housing, characterized in that the housing is a hollow, rotating cavity structure, with an input end and an output end at both ends. Inside the housing, from the input end to the output end, are sequentially arranged a sun gear, a first planet gear, a second planet gear, an internal gear ring, and a planet carrier. 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 located at the center of the inner cavity of the housing near the input end. A first bearing is fitted onto the inner wall of the housing near the output end. The right side of the planet carrier is fitted inside the first bearing and abuts against the inner ring of the first bearing. The internal gear ring is fitted onto the inner wall of the housing and is close to the end face of the first bearing. The sun gear is mounted on the center of the left side of the planetary carrier. One end of the sun gear extends outside the housing, and the other end of the sun gear is a toothed part. The side of the toothed part of the sun gear abuts against the left side of the planetary carrier through bearing two. At least two planet gears, planet gear two and a gear connecting shaft are distributed in a ring between the left side and the right side of the planetary carrier. The two ends of the gear connecting shaft are respectively located on the left side and the right side of the planetary carrier. Planet gear one and planet gear two are mounted on the gear connecting shaft. Planet gear one is closer to the left side of the planetary carrier, and planet gear two is closer to the right side of the planetary carrier. Planet gear one meshes with the sun gear, and planet gear two meshes with the internal gear ring.

[0007] The sun gear, planet carrier, and internal gear ring are arranged coaxially.

[0008] The sun gear, planet gear one, planet gear two, and internal gear ring are all bevel gears.

[0009] The sun gear and planet gear one, as well as planet gear two and the internal gear ring, are engaged at their large ends.

[0010] Both planetary gear one and planetary gear two are keyed to the gear connecting shaft and rotate synchronously.

[0011] The number of teeth on planetary gear one is greater than the number of teeth on planetary gear two.

[0012] The taper inclinations of planetary gear one and planetary gear two are opposite.

[0013] Both planetary gear one and planetary gear two are mounted on the planet carrier by axial positioning and clamping, so that planetary gear one can maintain tight meshing with the sun gear and planetary gear two can maintain tight meshing with the internal gear ring.

[0014] Using the above structure, the planetary gears are mounted on the planetary carrier by axial positioning and clamping, achieving low or zero backlash meshing between the planetary gears and the sun gear or internal gear ring, as well as high-precision transmission.

[0015] The working principle of this invention is as follows: After the NW planetary reducer is assembled, the bevel gear sun gear is connected to the external power transmission mechanism through the input end of the housing to obtain power. Then, the bevel gear sun gear rotates, simultaneously driving each bevel gear planet gear one to rotate synchronously. Each bevel gear planet gear one, after receiving the power of the first stage of reduction, begins to rotate on its own axis and transmits the power of the first stage of reduction synchronously to each bevel gear planet gear two through the gear connecting shaft. This drives each bevel gear planet gear two to mesh with the bevel gear internal gear ring to achieve rotation on its own axis while revolving around the bevel gear sun gear, and also drives the planet carrier to rotate, realizing the second stage of planetary transmission reduction. Then, the planet carrier transmits the reduced power through the machine... The output end of the housing is connected to an external transmission mechanism to realize power output. In the deceleration and power transmission operation of the reducer of the present invention, the sun gear, planet gear one, planet gear two and internal gear ring are all bevel gears, and the sun gear and planet gear one, and planet gear two and internal gear ring are all large-end meshing. While realizing high load-bearing meshing at the large end, it makes planet gear one and planet gear two located on the same shaft, the number of teeth of planet gear one is greater than the number of teeth of planet gear two, and the large and small ends of planet gear one and planet gear two are opposite. This not only realizes the effect of two-stage transmission and expanding the transmission ratio range, but also achieves the effect of high transmission ratio while offsetting axial force and realizing zero or small backlash.

[0016] This invention innovatively utilizes a two-stage bevel gear planetary transmission in a humanoid robot joint reducer. Due to the use of bevel gears, the manufacturing process is better than that of harmonic reducers, meeting the high precision requirements of humanoid robot joints. Furthermore, its transmission efficiency is higher than that of harmonic reducers. Secondly, because of the two-stage transmission, the total transmission ratio of the reducer can reach a wide range. Thirdly, the two-stage bevel gear planetary gears are located on the same shaft, and the large and small ends of the two-stage bevel gear planetary gears are in opposite directions. Therefore, the axial force can be canceled by controlling the cone angle of the two-stage bevel gear planetary gears, reducing the requirements for bearings.

[0017] 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.

[0018] 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.

[0019] The first cylindrical structure and the second cylindrical structure are coaxially arranged and have the same inclination direction. The two ends of the gear connecting shaft are respectively sleeved in the first cylindrical structure and the second cylindrical structure through bearing three. The gear connecting shaft is coaxial with the first cylindrical structure and the second cylindrical structure.

[0020] Compared with existing technologies, this high-precision zero-backlash NW planetary reducer has the following advantages:

[0021] 1. After the NW planetary reducer of the present invention is assembled, the bevel gear sun gear is connected to the external power transmission mechanism through the input end of the housing to obtain power. Then, the bevel gear sun gear rotates, which simultaneously drives each bevel gear planet gear one to rotate synchronously. Each bevel gear planet gear one obtains the power after the first stage of reduction and begins to rotate. It transmits the power after the first stage of reduction to each bevel gear planet gear two through the gear connecting shaft. This drives each bevel gear planet gear two to mesh with the bevel gear internal gear ring to achieve rotation while revolving around the bevel gear sun gear, and drives the planet carrier to rotate, realizing the second stage of 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.

[0022] 2. In the deceleration and power transmission operation of the reducer of the present invention, the sun gear, planet gear one, planet gear two, and internal gear ring are all bevel gears. The sun gear and planet gear one, and planet gear two and internal gear ring are all engaged at the large end. While achieving high load-bearing engagement at the large end, planet gear one and planet gear two are located on the same shaft. The number of teeth of planet gear one is greater than the number of teeth of planet gear two. The large and small ends of planet gear one and planet gear two are opposite. This not only achieves two-stage transmission and expands the transmission ratio range, but also achieves the effect of high transmission ratio while offsetting axial force and achieving zero or small backlash.

[0023] 3. This invention innovatively uses a two-stage bevel gear planetary transmission in the humanoid robot joint reducer. Due to the use of bevel gears, the manufacturing process is better than that of harmonic reducers, which can meet the high precision requirements of humanoid robot joints. At the same time, its transmission efficiency is higher than that of harmonic reducers. Secondly, due to the use of two-stage transmission, the total transmission ratio of the reducer can reach a wide range. Thirdly, the two-stage bevel gear planetary gears are located on the same shaft, and the large and small ends of the two-stage bevel gear planetary gears are opposite in direction. Therefore, the axial force can be canceled by controlling the cone angle of the two-stage bevel gear planetary gears, which reduces the requirements for bearings.

[0024] 4. In this invention, the planetary gears are mounted on the planet carrier by axial positioning and clamping, so as to achieve small or zero backlash meshing between the planetary gears and the sun gear or internal gear ring, and high-precision transmission. Attached Figure Description

[0025] Figure 1 This is a perspective view of the assembly of an embodiment of the present invention.

[0026] Figure 2 This is an assembly plan view of an embodiment of the present invention.

[0027] Figure 3 yes Figure 2AA section view.

[0028] Figure 4 This is a perspective view of the casing in an embodiment of the present invention.

[0029] Figure 5 This is a perspective view of the internal gear ring in an embodiment of the present invention.

[0030] Figure 6 This is a perspective view of the sun gear in an embodiment of the present invention.

[0031] Figure 7 This is a perspective view of the left side of the planetary carrier in an embodiment of the present invention.

[0032] Figure 8 This is a perspective view of the right side of the planetary carrier in an embodiment of the present invention.

[0033] Figure 9 This is a perspective view of planetary gear one in an embodiment of the present invention.

[0034] Figure 10 This is a perspective view of planetary gear two in an embodiment of the present invention.

[0035] Figure 11 This is a perspective view of the gear connecting shaft in an embodiment of the present invention.

[0036] Figure 12 This is an assembly effect diagram of an embodiment of the present invention.

[0037] Figure 13 This is an exploded view of an embodiment of the present invention.

[0038] Figure 14 This is a schematic diagram of the transmission system according to an embodiment 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 one; 4. Planetary gear two; 5. Sun gear; 6. Internal gear ring; 7. Bearing one; 8. Bearing two; 9. Bearing three; 10. Gear connecting shaft. 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 1-14As shown, this embodiment provides a high-precision zero-backlash NW planetary reducer, including a housing 1. The housing 1 is a hollow rotary cavity structure. The hollow structure of the housing can integrate a motor inside, achieving a small and compact integrated motor and gearbox. 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, are arranged sequentially a sun gear 5, a first planet gear 3, a second planet gear 4, an internal gear ring 6, and a planet carrier 2. The planet carrier 2 is divided into a left side part and a right side part arranged opposite to each other. The left side part 2a of the planet carrier is located in the center of the inner cavity of the housing 1 near the input end. A first bearing 7 is sleeved on the inner wall of the housing 1 near the output end. The right side part 2b of the planet carrier is sleeved in the first bearing 7 and abuts against the inner ring of the first bearing 7. The internal gear ring 6 is sleeved on the inner wall of the housing 1. The sun gear 5 is mounted on the center of the left side portion 2a of the planetary carrier, near the end face of bearing 7. One end of the sun gear 5 extends outside the housing 1, and the other end of the sun gear 5 is a toothed part. The side of the toothed part of the sun gear 5 abuts against the left side portion 2a of the planetary carrier through bearing 8. At least two planet gears 3, 4 and a gear connecting shaft 10 are distributed in a ring between the left side portion 2a and the right side portion 2b of the planetary carrier. The two ends of the gear connecting shaft 10 are respectively set on the left side portion 2a and the right side portion 2b of the planetary carrier. The planet gears 3 and 4 are mounted on the gear connecting shaft 10. The planet gear 3 is close to the left side portion 2a of the planetary carrier, and the planet gear 4 is close to the right side portion 2b of the planetary carrier. The planet gear 3 meshes with the sun gear 5, and the planet gear 4 meshes with the internal gear ring 6.

[0043] The sun gear 5, planet carrier 2, and internal gear ring 6 are coaxially arranged; the sun gear 5, planet gear 3, planet gear 4, and internal gear ring 6 are all bevel gears; the sun gear 5 and planet gear 3, and planet gear 4 and internal gear ring 6 are engaged at their large ends; planet gear 3 and planet gear 4 are both keyed and mounted on the gear connecting shaft 10 and rotate synchronously; the number of teeth of planet gear 3 is greater than the number of teeth of planet gear 4; the taper inclination directions of planet gear 3 and planet gear 4 are opposite; through the above structural arrangement, the planet gear 3 and the sun gear 5 are engaged with zero backlash, and the planet gear 4 and the internal gear ring 6 are engaged with zero backlash, achieving a compact structure and high transmission accuracy.

[0044] Planetary gear 3 and planetary gear 4 are both mounted on the planet carrier 2 by axial positioning and clamping, so that planetary gear 3 can maintain tight meshing with sun gear 5 and planetary gear 4 can maintain tight meshing with internal gear ring 6. With the above structure, the planetary gears are mounted on the planet carrier 2 by axial positioning and clamping, which achieves small or zero backlash meshing between the planetary gears and sun gear 5 or internal gear ring 6 and high-precision transmission.

[0045] The working principle of this invention is as follows: After the NW planetary reducer of this invention is assembled, the bevel gear sun gear 5 is connected to the external power transmission mechanism through the input end of the housing 1 to obtain power. Then, the bevel gear sun gear 5 rotates, simultaneously driving each bevel gear planet gear 3 to rotate synchronously. Each bevel gear planet gear 3, after receiving the power of the first stage of reduction, begins to rotate on its own axis and transmits the power of the first stage of reduction synchronously to each bevel gear planet gear 4 through the gear connecting shaft 10. This drives each bevel gear planet gear 4 to mesh with the bevel gear internal gear ring 6 to achieve rotation on its own axis while revolving around the bevel gear sun gear 5, and also drives the planet carrier 2 to rotate, realizing the second stage of planetary transmission reduction. Then, the planet carrier 2 transmits the reduced power through the housing. The output end of 1 is connected to an external transmission mechanism to realize power output. In the deceleration and power transmission operation of the reducer of the present invention, the sun gear 5, planet gear 3, planet gear 4 and internal gear ring 6 are all bevel gears. The sun gear 5 and planet gear 3, and planet gear 4 and internal gear ring 6 are all engaged at the large end. While realizing high load-bearing engagement at the large end, the planet gear 3 and planet gear 4 are located on the same shaft. The number of teeth of planet gear 3 is greater than the number of teeth of planet gear 4. The large and small ends of planet gear 3 and planet gear 4 are opposite. This not only realizes two-stage transmission and expands the transmission ratio range, but also achieves the effect of high transmission ratio while offsetting axial force and realizing zero or small backlash.

[0046] This invention innovatively utilizes a two-stage bevel gear planetary transmission in a humanoid robot joint reducer. Due to the use of bevel gears, the manufacturing process is better than that of harmonic reducers, meeting the high precision requirements of humanoid robot joints. Furthermore, its transmission efficiency is higher than that of harmonic reducers. Secondly, because of the two-stage transmission, the total transmission ratio of the reducer can reach a wide range. Thirdly, the two-stage bevel gear planetary gears are located on the same shaft, and the large and small ends of the two-stage bevel gear planetary gears are in opposite directions. Therefore, the axial force can be canceled by controlling the cone angle of the two-stage bevel gear planetary gears, reducing the requirements for bearings.

[0047] 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 gear connecting shaft 10 are respectively sleeved in the cylindrical structures 1 and 2 through bearings 3 and 9. The gear connecting shaft 10 is coaxial with the cylindrical structures 1 and 2. With 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 and the sun gear 5 at a specific angle between their central axes. For specific principles and examples, please refer to the prior applications mentioned in the background art of this application.

[0048] In this embodiment, planetary gear 3 and planetary gear 4 are three identical gears arranged in a ring around the central axis of the sun gear 5. There are three gear connecting shafts 10. The sun gear 5 is a hollow gear shaft for easy connection to an external motor. There is one bearing 7 and one bearing 8, and six bearings 9 arranged in pairs opposite each other. The central axes of planetary gear 3, planetary gear 4, and gear connecting shafts 10 all intersect on the central axis of the sun gear 5, and the intersection point is located at the output end. See details below. Figure 14 .

[0049] 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 NW planetary 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, are arranged sequentially a sun gear, planet gear one, planet gear two, an internal gear ring, and a planet carrier. 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 located in the center of the inner cavity of the housing near the input end. A bearing one is fitted onto the inner wall of the housing near the output end. The right side of the planet carrier is fitted inside the bearing one and abuts against the inner ring of the bearing one. The internal gear ring is fitted onto the inner wall of the housing, near the end face of the bearing one. The sun gear is fitted onto the left side of the planet carrier. At the center of the machine, one end of the sun gear extends outside the housing, and the other end of the sun gear is a toothed part. The side of the toothed part of the sun gear abuts against the left side of the planet carrier through bearing two. At least two planet gears, planet gear two and a gear connecting shaft are distributed in a ring between the left side and the right side of the planet carrier. The two ends of the gear connecting shaft are respectively set on the left side and the right side of the planet carrier. Planet gear one and planet gear two are sleeved on the gear connecting shaft. Planet gear one is closer to the left side of the planet carrier, and planet gear two is closer to the right side of the planet carrier. Planet gear one meshes with the sun gear, and planet gear two meshes with the internal gear ring.

2. The high-precision zero-backlash NW planetary reducer according to claim 1, characterized in that, The sun gear, planet carrier, and internal gear ring are arranged coaxially.

3. The high-precision zero-backlash NW planetary reducer according to claim 2, characterized in that, The sun gear, planet gear one, planet gear two, and internal gear ring are all bevel gears.

4. The high-precision zero-backlash NW planetary reducer according to claim 3, characterized in that, The sun gear and planet gear one, as well as planet gear two and the internal gear ring, are engaged at their large ends.

5. The high-precision zero-backlash NW planetary reducer according to claim 4, characterized in that, Both planetary gear one and planetary gear two are keyed to the gear connecting shaft and rotate synchronously.

6. The high-precision zero-backlash NW planetary reducer according to claim 5, characterized in that, The number of teeth on planetary gear one is greater than the number of teeth on planetary gear two.

7. The high-precision zero-backlash NW planetary reducer according to claim 6, characterized in that, The taper inclinations of planetary gear one and planetary gear two are opposite.

8. The high-precision zero-backlash NW planetary 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 NW planetary reducer according to claim 8, 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 NW planetary reducer according to claim 9, characterized in that, The first cylindrical structure and the second cylindrical structure are coaxially arranged and have the same inclination direction. The two ends of the gear connecting shaft are respectively sleeved in the first cylindrical structure and the second cylindrical structure through bearing three. The gear connecting shaft is coaxial with the first cylindrical structure and the second cylindrical structure.

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