Joint structure and robot

Abstract

The present application provides a joint structure and a robot. The joint structure comprises: a driving member; a planetary reducer, wherein the planetary reducer is provided with a first transmission end, the first transmission end is drivingly connected to the driving member, the planetary reducer comprises a planetary carrier which provides a predetermined reduction ratio with the first transmission end, and the planetary carrier is provided with a gear portion; and an RV reducer, which is drivingly connected to the gear portion, the driving member, the planetary reducer, and the RV reducer being coaxially arranged and being hollow. The present application solves the problem in the prior art of low power density of a robot joint.

Description

Joint structure and robot

[0001] The present application claims priority to the patent application with the application number 202410980911.9, filed on July 19, 2024, with the State Intellectual Property Office of China, and the title of “Joint structure and robot”, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the field of robots, in particular, to a joint structure and a robot. BACKGROUND

[0003] In the prior art, an RV reducer is used in a large-load robot joint. If the reduction ratio of the RV reducer is too large, the hollow hole will be small, which will cause design difficulties. Therefore, the reduction ratio of the RV reducer is small. In this case, a motor with greater driving force is needed to drive the large load, which increases the weight and volume of the entire robot. Therefore, the power density (i.e., the power per unit mass / volume) of the existing robot joint is low. At the same time, there is a problem that hollow wiring and reduction ratio requirements cannot be considered at the same time. In addition, in the existing RV reducer scheme, a parallel shaft layout form is often used. As a result, the axial length of the robot is too long, and the moment of inertia relative to other joint axes is large, which is not conducive to the overall structure design and motion control. SUMMARY

[0004] The main purpose of the present application is to provide a joint structure and a robot to solve the problem of low power density of the robot joint in the prior art.

[0005] In order to achieve the above-mentioned purpose, according to an optional embodiment of the present application, a joint structure is provided, comprising: a driving member; a planetary reducer, the planetary reducer having a first transmission end, the first transmission end being drivingly connected with the driving member, the planetary reducer comprising a planet carrier forming a predetermined reduction ratio with the first transmission end, the planet carrier having a gear portion; an RV reducer, the RV reducer being drivingly connected with the gear portion, the center axes of the driving member, the planetary reducer and the RV reducer being coaxial and hollow.

[0006] In an optional embodiment, the planetary reducer comprises: a sun gear, the sun gear being located at the center axis of the planetary reducer, the sun gear having the first transmission end and being drivingly connected with the driving member; a planet gear, the planet gear being located at the circumferential side of the sun gear and being in meshing transmission with the sun gear; the planet carrier comprising an axial large-diameter section and a small-diameter section in sequence, the large-diameter section being connected with the planet gear and rotating around the axis of the sun gear under the driving of the planet gear, the small-diameter section having a gear structure on the outer circumferential side and serving as the gear portion.

[0007] In an optional embodiment, the driving member has an output shaft at the central axis of the driving member, the output shaft, the sun gear and the planet carrier all have hollow structures, and the RV reducer has a hollow structure at the central axis, and the hollow structure is coaxially communicated with the hollow structure.

[0008] In an optional embodiment, the RV reducer comprises a first reduction mechanism and a second reduction mechanism, the first reduction mechanism and the second reduction mechanism are drivingly connected and form a two-stage reduction mechanism, and one of the first reduction mechanism and the second reduction mechanism is drivingly connected with the gear part.

[0009] In an optional embodiment, the joint structure further comprises a low-speed shaft, the low-speed shaft is arranged at the central axes of the driving member, the planetary reducer and the RV reducer, and is drivingly connected with the RV reducer.

[0010] In an optional embodiment, the joint structure further comprises a first encoder, the first encoder is connected with the low-speed shaft, at least a part of the first encoder is driven to rotate by the low-speed shaft, and the first encoder is located at a side of the driving member away from the RV reducer.

[0011] In an optional embodiment, the joint structure further comprises a second encoder, the driving member has an output shaft, the second encoder is connected with the output shaft, at least a part of the second encoder is driven to rotate by the output shaft, and the second encoder and the first encoder are located at the same side of the driving member.

[0012] In an optional embodiment, the joint structure further comprises a brake device, the driving member has an output shaft, one end of the output shaft is drivingly connected with the planetary reducer, and the other end of the output shaft is drivingly connected with the brake device.

[0013] In an optional embodiment, the driving member comprises a housing and an output shaft, the output shaft is rotatably arranged in the housing and both ends of the output shaft pass through the housing, the driving member further comprises a bearing and an oil seal, the bearing and the oil seal are arranged between the housing and the output shaft, and the oil seal is farther away from the inner side of the housing than the bearing.

[0014] According to an optional embodiment of the present application, a robot is provided, comprising the joint structure described above.

[0015] The technical scheme of the application is applied, the planetary reducer is additionally arranged between the driving member and the RV reducer, so that the planetary reducer can assist in reducing the overall reduction ratio, thereby improving the output capacity of the joint and meeting the design requirement of large reduction ratio. Meanwhile, the gear part is arranged on the planet carrier and connected between the gear part and the RV reducer, so that the gear part can serve as the input shaft of the RV reducer, and part of the planet carrier serves as the input shaft of the RV reducer. In this way, the structure between the planetary reducer and the RV reducer can be more compact, thereby being beneficial to reducing the size of the joint structure, cooperating with the effect of improving the output capacity of the joint, and improving the power density of the joint structure as a whole, so that the power density of the joint structure is greatly improved, and the joint structure is miniaturized and high-powered. In addition, the coaxial arrangement of the central axes of the driving member, the planetary reducer and the RV reducer can ensure that the driving member, the planetary reducer and the RV reducer adopt the hollow wiring mode under the condition of meeting the reduction ratio requirement, solve the contradiction between the reduction ratio and the hollow wiring, realize the effect of large hollow and large reduction ratio, and is also beneficial to shortening the axial length when the driving member, the planetary reducer and the RV reducer are connected, reducing the size of the joint structure, and not reducing the power of the driving member, so as to achieve the purposes of compact structure, large output torque, high transmission efficiency and high power density, thereby being beneficial to the overall structure design and motion control of the robot. BRIEF DESCRIPTION OF DRAWINGS

[0016] The drawings accompanying the specification of the present application form a part thereof, serve to provide further understanding of the present application, and together with the specification explain the application. The use of these drawings in explaining the application is in no way intended as a limitation on the full scope of the application, and the illustrations are instead intended to serve as an aid in understanding the application.

[0017] Fig. 1 shows a structural schematic view of a joint structure of the present application;

[0018] Fig. 2 is a sectional view of the joint structure;

[0019] Fig. 3 is an axonometric view of Fig. 2.

[0020] In the above drawings, the following reference signs are used: 10, driving member; 11, output shaft; 12, housing; 13, bearing; 14, oil seal; 20, planetary reducer; 21, sun gear; 22, planet gear; 23, planet carrier; 30, RV reducer; 50, first encoder; 60, second encoder; 70, brake device. DETAILED DESCRIPTION

[0021] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0022] In order to solve the problem of low power density of the robot joint in the prior art, the application provides a joint structure and a robot, wherein the robot comprises the joint structure described below.

[0023] The joint structure shown in FIGS. 1-3 comprises a driving member 10, a planetary reducer 20 and an RV reducer 30. The planetary reducer 20 has a first transmission end which is drivingly connected with the driving member 10. The planetary reducer 20 comprises a planetary carrier 23 which forms a predetermined reduction ratio with the first transmission end. The planetary carrier 23 has a gear portion. The RV reducer 30 is drivingly connected with the gear portion. The central axes of the driving member 10, the planetary reducer 20 and the RV reducer 30 are coaxial and hollow.

[0024] In the embodiment, the planetary reducer 20 is additionally arranged between the driving member 10 and the RV reducer 30, so that the planetary reducer 20 can assist in reducing the overall reduction ratio, thereby improving the output capacity of the joint and meeting the design requirement of large reduction ratio. Meanwhile, the gear portion is arranged on the planetary carrier 23 and connected with the RV reducer 30, so that the gear portion can serve as the input shaft of the RV reducer 30, that is, part of the planetary carrier 23 serves as the input shaft of the RV reducer 30. In this way, the structure between the planetary reducer 20 and the RV reducer 30 can be more compact, thereby being conducive to reducing the volume of the joint structure and achieving the effect of improving the power density of the joint structure as a whole, so that the power density of the joint structure is greatly improved, and the joint structure is miniaturized and high-powered. In addition, the coaxial arrangement of the central axes of the driving member 10, the planetary reducer 20 and the RV reducer 30 can ensure that the driving member 10, the planetary reducer 20 and the RV reducer 30 adopt the hollow wiring mode under the condition of meeting the reduction ratio requirement, thereby solving the contradiction between the reduction ratio and the hollow wiring, achieving the effect of large hollow and large reduction ratio, and being conducive to shortening the axial length when the driving member 10, the planetary reducer 20 and the RV reducer 30 are connected, reducing the volume of the joint structure, and not reducing the power of the driving member 10, thereby achieving the purposes of compact structure, large output torque, high transmission efficiency, high power density, and being conducive to the overall structural design and motion control of the robot.

[0025] In the embodiment, the RV reducer 30 comprises a first reduction mechanism and a second reduction mechanism which are drivingly connected and form a two-stage reduction mechanism, one of the first reduction mechanism and the second reduction mechanism is drivingly connected with the gear part, so that on the one hand, the RV reducer 30 can be directly matched with the planetary reducer 20, and the separate input shaft and other components are no longer needed, thereby facilitating the compactness of the structure and the shortening of the axial length, on the other hand, the RV reducer 30 and the planetary reducer 20 together form a three-stage reduction mechanism, compared with the traditional two-stage reduction mechanism, the embodiment can provide higher torque, thereby facilitating the joint structure to better perform tasks, such as the joint structure to grasp heavy objects, to perform precise force control operations, etc. Optionally, the first reduction mechanism can adopt a planetary reducer, and the second reduction mechanism can adopt a cycloid reducer, and the first reduction mechanism is coaxially connected with the gear part. Of course, the RV reducer 30 can also adopt other two-stage reduction arrangement modes which can achieve the purpose of large torque output, such as adopting a planetary reducer and a harmonic reducer to form a two-stage reduction mechanism, etc.

[0026] In the embodiment, the planetary reducer 20 comprises a sun gear 21, a planet gear 22 and a planet carrier 23, the sun gear 21 is located at the central axis of the planetary reducer 20, the sun gear 21 has a first driving end and is drivingly connected with the driving member 10, the planet gear 22 is a plurality of and is uniformly distributed on the circumferential side of the sun gear 21 and is in meshing transmission with the sun gear 21, the circumferential side of the planet gear 22 away from the sun gear 21 is provided with a gear ring, the inner side of the gear ring is provided with a ring of teeth, each planet gear 22 is in meshing transmission with the teeth on the inner side of the gear ring, and the gear ring provides an orbit for each planet gear 22 while playing a supporting and fixing role. The planet carrier 23 is arranged on the side of the planet gear 22 away from the driving member 10, and the planet carrier 23 of the embodiment comprises a large-diameter section and a small-diameter section in sequence in the axial direction, the large-diameter section is closer to the planet gear 22 than the small-diameter section, the non-circular center of the large-diameter section is connected with the planet gear 22, so that the planet gear 22 can drive the planet carrier 23 to rotate around the axis of the sun gear 21 when rotating, and the outer circumferential side of the small-diameter section has a gear structure and serves as a gear part, and the small-diameter section extends into the center of the RV reducer 30, thereby achieving meshing and cooperation with the RV reducer 30. In this way, during overall operation, the driving member 10 drives the sun gear 21 to rotate, the sun gear 21 drives the planet gear 22 to rotate, the planet gear 22 drives the planet carrier 23 to rotate, and the gear part on the planet carrier 23 drives the RV reducer 30 to move through meshing, thereby realizing the transmission function of the planetary reducer 20, and the rotation axes of the sun gear 21 and the planet carrier 23 are coaxially arranged, thereby realizing the coaxial arrangement of the input end and the output end of the planetary reducer 20, so as to facilitate the coaxial connection of the driving member 10 and the RV reducer 30, thereby improving the transmission efficiency of the joint structure and making the structure more compact.

[0027] As shown in FIG. 2 and FIG. 3, in the embodiment, the driving member 10 has an output shaft 11 located at the central axis of the driving member 10, the output shaft 11, the sun gear 21 and the planet carrier 23 all have a hollow structure, the RV reducer 30 has a hollow structure at the central axis, and the hollow structure and the hollow structure are coaxially communicated. In this way, the hollow structure and the hollow structure communicate the inside of the output shaft 11, the sun gear 21 and the planet carrier 23, and the RV reducer 30, so that an overall space can be formed at the hollow structure and the hollow structure, thereby being used for internal wiring or other mechanism arrangement, so as to optimize the wiring and structure arrangement of the joint structure, thereby making the joint structure smaller in size and more compact in structure.

[0028] In the embodiment, the joint structure further comprises a low-speed shaft, which is arranged at the central axis of the driving member 10, the planetary reducer 20 and the RV reducer 30 and is drivingly connected with the RV reducer 30. In this way, the low-speed shaft can be arranged at the hollow structure and the hollow structure, which not only can be coaxially arranged with the driving member 10, the planetary reducer 20 and the RV reducer 30, but also can improve the output capacity and stability of the joint structure without increasing the axial size of the joint structure, thereby reducing the space occupation.

[0029] In the embodiment, the joint structure further comprises a first encoder 50, which is connected with the low-speed shaft and is driven to rotate by at least a part of the low-speed shaft. The first encoder 50 is located at the side of the driving member 10 away from the RV reducer 30, that is, the first encoder 50 is arranged at the end of the low-speed shaft, and the code disc of the first encoder 50 rotates with the low-speed shaft, so as to measure the rotation speed and rotation angle of the end of the low-speed shaft and timely feedback the motion state of the low-speed shaft.

[0030] In the embodiment, the joint structure further comprises a second encoder 60, which is connected with the output shaft 11 of the driving member 10 and is driven to rotate by at least a part of the output shaft 11. The second encoder 60 and the first encoder 50 are located at the same side of the driving member 10, that is, the second encoder 60 is arranged at the end of the driving member 10 away from the RV reducer 30, and the code disc of the second encoder 60 is arranged on the output shaft 11 and rotates with the output shaft 11, so as to measure the rotation speed and rotation angle of the driving member 10 and timely feedback the motion state of the driving member 10. It should be noted that the first encoder 50 and the second encoder 60 should be avoided from interfering with each other during installation.

[0031] In the embodiment, the joint structure further comprises a brake device 70, the driving member 10 has an output shaft 11, one end of the output shaft 11 is drivingly connected with the planetary reducer 20, that is, connected with the sun gear 21, and the other end of the output shaft 11 is drivingly connected with the brake device 70, so that the brake device 70 can directly act on the output shaft 11 of the driving member 10, thereby improving the stability and safety of the driving member 10, and the action of the joint structure can be accurately controlled. When the driving member 10 is normally running, the rotation of the output shaft 11 is not affected by the brake device 70, and when the driving member 10 needs to be stopped, the driving member 10 is powered off, and the brake device 70 acts on the output shaft 11 to stop the rotation of the output shaft 11, thereby safely and stably stopping the action of the driving member 10, and further making the action of the joint structure more accurate and stable. Alternatively, the brake device 70 can be a finger chuck type brake device or a disc type brake device, which can achieve the purpose of stabilizing the output shaft 11.

[0032] In the embodiment, the driving member 10 comprises a housing 12 and an output shaft 11, the output shaft 11 is rotatably arranged in the housing 12, and both ends of the output shaft 11 pass through the housing 12, the driving member 10 further comprises a bearing 13 and an oil seal 14, both of which are arranged between the housing 12 and the output shaft 11, and the oil seal 14 is farther away from the inner side of the housing 12 than the bearing 13. Specifically, the driving member 10 of the embodiment can use an inner rotor motor, a disc motor, etc., the motor shaft is used as the output shaft 11 and is arranged on the central axis of the driving member 10, the housing 12 is arranged outside the motor shaft to support and protect the motor shaft, the end of the motor shaft close to the sun gear 21 is provided with the bearing 13 and the oil seal 14, and the oil seal 14 is closer to the sun gear 21 than the bearing 13, so that the oil seal 14 seals the bearing 13 between the housing 12 and the output shaft 11, thereby protecting the bearing and preventing leakage of lubricating oil, thereby ensuring normal operation of the driving member 10. Of course, the end of the motor shaft away from the sun gear 21 is also provided with a bearing 13, and the oil seal 14 can be correspondingly arranged on the side of the bearing 13 away from the sun gear 21, so that the bearings 13 at both ends of the driving member 10 can be effectively protected to ensure normal operation of the driving member 10.

[0033] It should be noted that the plurality in the above embodiment means at least two.

[0034] From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects:

[0035] 1. The problem of low power density of the robot joint in the prior art is solved;

[0036] 2. The planetary reducer can assist to reduce the overall reduction ratio, thereby improving the output capacity of the joint and meeting the design requirement of large reduction ratio;

[0037] 3. The part of the planet carrier is the input shaft of the RV reducer, so that the structure between the planetary reducer and the RV reducer can be more compact, thereby facilitating the reduction of the volume of the joint structure, and the overall effect of improving the power density of the joint structure, so that the power density of the joint structure is greatly improved, realizing the miniaturization and high power of the joint structure;

[0038] 4. The hollow wiring mode can be used for the driving member, the planetary reducer and the RV reducer under the condition of ensuring the reduction ratio requirement, solving the contradiction between the reduction ratio and the hollow wiring, and realizing the effect of large hollow and large reduction ratio;

[0039] 5. It is beneficial to shorten the axial length when the driving member, the planetary reducer and the RV reducer are connected, reduce the volume of the joint structure, and will not reduce the power of the driving member, so as to achieve the purpose of compact structure, large output torque, high transmission efficiency and high power density, thereby facilitating the overall structure design and motion control of the robot.

[0040] Obviously, the above-described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0041] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various changes and modifications to the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An articulating structure, characterized by, The joint structure comprises: a driving member (10); a planetary reducer (20) having a first driving end drivingly connected with the driving member (10), the planetary reducer (20) comprising a planet carrier (23) forming a predetermined reduction ratio with the first driving end, the planet carrier (23) having a gear portion; an RV reducer (30) drivingly connected with the gear portion, the center axes of the driving member (10), the planetary reducer (20) and the RV reducer (30) being coaxial and hollow.

2. The joint structure according to claim 1, characterized in that, The planetary reducer (20) comprises: a sun gear (21) located at the center axis of the planetary reducer (20), the sun gear (21) having the first driving end and drivingly connected with the driving member (10); a planet gear (22) located at the circumferential side of the sun gear (21) and meshingly drivingly connected with the sun gear (21); the planet carrier (23) comprising an axially sequentially arranged large-diameter section and a small-diameter section, the large-diameter section being connected with the planet gear (22) and rotating around the axis of the sun gear (21) under the driving of the planet gear (22), the small-diameter section having a gear structure on the outer circumferential side and serving as the gear portion.

3. The joint structure of claim 2, wherein The driving member (10) has an output shaft (11) located at the center axis of the driving member (10), the output shaft (11), the sun gear (21) and the planet carrier (23) all having a hollow structure, the center axis of the RV reducer (30) having a hollow structure, the hollow structure being coaxially and communicatively arranged with the hollow structure.

4. The joint structure of claim 1, wherein The RV reducer (30) comprises a first reduction mechanism and a second reduction mechanism drivingly connected and forming a two-stage reduction mechanism, one of the first reduction mechanism and the second reduction mechanism being drivingly connected with the gear portion.

5. The joint structure of claim 1, wherein The joint structure further comprises a low-speed shaft passing through the center axes of the driving member (10), the planetary reducer (20) and the RV reducer (30) and drivingly connected with the RV reducer (30).

6. The joint structure of claim 5, wherein The joint structure further comprises a first encoder (50) connected with the low-speed shaft, at least a part of the first encoder (50) being rotated by the low-speed shaft, the first encoder (50) being located on the side of the driving member (10) away from the RV reducer (30).

7. The joint structure of claim 6, wherein The joint structure further comprises a second encoder (60) connected with the output shaft (11) of the driving member (10), at least a part of the second encoder (60) being rotated by the output shaft (11), the second encoder (60) and the first encoder (50) being located on the same side of the driving member (10).

8. The joint structure of claim 1, wherein The joint structure further comprises a brake device (70), the driving member (10) has an output shaft (11), one end of the output shaft (11) is drivingly connected with the planetary reducer (20), and the other end of the output shaft (11) is drivingly connected with the brake device (70).

9. The joint structure of claim 1, wherein The driving member (10) comprises a housing (12) and an output shaft (11), the output shaft (11) is rotatably arranged in the housing (12), and both ends of the output shaft (11) pass through the housing (12), the driving member (10) further comprises a bearing (13) and an oil seal (14), the bearing (13) and the oil seal (14) are arranged between the housing (12) and the output shaft (11), and the oil seal (14) is farther away from the inner side of the housing (12) than the bearing (13).

10. A robot, characterized in that The joint structure comprises any one of claims 1 to 9.

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