A highly integrated and high-performance robot joint unit

Abstract

The present invention discloses a highly integrated and high-performance robot joint unit, belonging to the field of robot equipment technology. When the reducer of the existing robot joint is in an overload working state, it will cause damage to the joint parts such as the reducer gear, and the meshing tooth surface of each tooth of the reducer will show a relatively serious uneven wear phenomenon. In the present invention, when the torque transmitted to the ring gear by the output end of the motor rotor or the reducer assembly is greater than the friction torque between the ring gear and the motor base, the ring gear of the reducer assembly will be driven by the motor rotor or the output end of the reducer assembly to overcome the friction torque generated by the friction force generator, so that the ring gear and the motor base rotate relative to each other, and the friction slip between the reducer assembly and the motor base is realized, and the torque borne by the reducer assembly is limited, thereby preventing the reducer itself from being damaged due to the large torque borne from the motor end or the output end of the joint unit.

Description

Technical Field

[0001] The invention relates to a highly integrated and high-performance robot joint unit, belonging to the technical field of robot equipment. Background Art

[0002] High-performance robot joint power unit is the core component of the robot, and its performance directly affects the robot's motion performance. For an ideal robot joint power unit, it needs to have the characteristics of high output torque / weight density, simple and compact structure, and low manufacturing cost.

[0003] For joint power units used in occasions such as high-performance legged robots, robotic arms or exoskeletons, due to the complex and changeable terrain of the ground or the impact interference force from the outside, when the driving torque of the robot joint motor is greater than the maximum torque that the joint reducer can withstand or the maximum torque from the outside transmitted to the reducer through the reducer output shaft is greater than the maximum torque that the joint reducer can withstand, the reducer of the robot joint will be in an overloaded working state, which will cause damage to joint components such as the reducer gears.

[0004] Moreover, because the robot joints work in reciprocating mode for a long time under these working conditions and need to bear the impact load from the ground or the external environment, the meshing tooth surfaces of the reducer teeth will show serious uneven wear.

[0005] Furthermore, in order to meet the requirements of high output torque / weight density, simple and compact structure, and low production cost, common robot joint power units often sacrifice the following features: the joint unit does not have a central axis hole, and thus hollow wiring cannot be achieved. The cables are directly hung outside the robot joint, affecting the safety and aesthetics of the robot structure. Summary of the invention

[0006] In view of the defects of the prior art, the purpose of the present invention is to provide a highly integrated and high-performance robot joint unit which can achieve friction and slip, realize torque limitation, is suitable for a variety of complex working conditions, and will not cause damage to joint parts when the joints are subjected to impact loads.

[0007] Another object of the present invention is to provide a joint unit with an axial hole, which can realize hollow wiring or connect other components, and has a beautiful and compact structure and high integration and high performance robot joint unit.

[0008] To achieve the above object, the technical solution of the present invention is:

[0009] A highly integrated and high-performance robot joint unit includes a motor assembly and a reducer assembly for driving the joint movement, wherein the motor assembly includes a motor rotor for outputting torque and a motor base;

[0010] The reducer assembly is provided with a gear ring, and the gear ring is in contact connection with the motor base under the action of the friction force generator;

[0011] When the torque transmitted from the motor rotor or the output end of the reducer assembly to the ring gear is less than the friction torque between the ring gear and the motor base, the ring gear of the reducer assembly is fixed on the motor base under the action of the friction torque generated by the friction force generator, and the motor rotor drives the output end of the reducer assembly to rotate;

[0012] In the present invention, when the torque transmitted to the ring gear from the output end of the motor rotor or the reducer assembly is greater than the friction torque between the ring gear and the motor base, the ring gear of the reducer assembly will be driven by the motor rotor or the output end of the reducer assembly to overcome the friction torque generated by the friction force generator, so that the ring gear and the motor base rotate relative to each other, thereby achieving friction and slippage between the reducer assembly and the motor base, and limiting the torque borne by the reducer assembly, thereby preventing the reducer itself from being damaged due to the large torque borne from the motor end or the output end of the joint unit, so that the present invention can be applied to various complex working conditions, and the joint components will not be damaged when the joint is subjected to impact loads.

[0013] As an optimal technical measure, the motor rotor is connected to the inner cavity of the motor base, a front end cover is provided on the outer side of the motor base, and the friction force generator is assembled in the accommodating cavity formed by the motor base and the front end cover. The structure is compact and reliable and easy to produce.

[0014] As a preferred technical measure, the front end cover is fixedly connected to the motor base, and a friction generator is extruded and assembled in its inner cavity. The friction generator pushes the gear ring so that the gear ring and the motor base are extruded and frictionally matched together; the gear ring has an annular friction surface. The annular friction surface increases the friction area between the gear ring and the friction generator or the motor base, reduces wear and improves heat dissipation performance.

[0015] As an optimal technical measure, the gear ring is provided with an annular friction disc, and the friction disc is frictionally connected to the motor base or the gear ring; the friction disc is made of wear-resistant material; using an independent friction disc is convenient for future maintenance and replacement.

[0016] As a preferred technical measure, an output encoder with a hollow structure is installed between the planetary gear carrier and the motor base; a motor encoder is installed between the motor rotor and the motor base; the motor encoder and the output encoder include but are not limited to magnetic encoders, inductive encoders, capacitive encoders, rotary transformers, and photoelectric encoders; the output encoder is mainly used to achieve real-time angle detection of the output end of the reducer assembly when the gear ring slides frictionally.

[0017] The present invention adds an encoder between the planetary gear frame and the motor base, so that the present invention has the ability to detect the angle of the output shaft end while ensuring the compact structure of the present invention; compared with the joint unit that only has an encoder at the motor end, the controlled performance is greatly improved.

[0018] As a preferred technical measure, the friction force generator is a passive elastic element, including but not limited to a disc spring, a wave spring, and a coil spring, which has a simple and reliable structure and a low manufacturing cost.

[0019] As a preferred technical measure, the friction force generator is an active control unit that can generate extrusion force so that the gear ring and the motor base can be tightly squeezed and frictionally matched together; the active control unit includes but is not limited to electromagnets and electrostrictive materials. After adopting the active control unit, the friction force generator can dynamically adjust the maximum friction torque between the gear ring and the motor base in real time according to actual needs, so that the joint unit can adapt to various working conditions.

[0020] As a preferred technical measure,

[0021] The motor assembly also includes a motor stator and windings, and a motor rear end cover;

[0022] The reducer assembly also includes a sun gear, a planetary gear, a ring gear, a planetary gear carrier, an output flange and an output bearing end cover;

[0023] The friction disc, friction force generator and front end cover constitute a torque limiting assembly;

[0024] The motor base, friction disc, gear ring, friction force generator and front end cover together constitute a friction torque limiting mechanism.

[0025] The present invention has the ability to limit torque, and realizes the torque limit from the motor to the output flange and the torque limit from the output flange to the motor end. The reliability of the robot joint unit is greatly improved. In addition, the occasional slipping of the reducer gear ring relative to the motor base caused by the torque limit is conducive to balancing the wear of the entire reducer, greatly increasing the life of the joint unit.

[0026] As a preferred technical measure, the shaft of the motor rotor has a hollow structure; the shaft of the motor rotor is an integral structure with the motor rotor or a separate but fixedly connected structure; the motor encoder has a hollow structure; the sun gear also has a hollow structure, and the sun gear is fixedly connected to the motor rotor. The joint unit of the present invention has an axial hole, so that the present invention has a hollow structure under the premise of compact structure and high torque / weight density, which is convenient for hollow wiring or connecting other components when the joint unit is actually used. At the same time, the cable is assembled inside the joint unit, making the joint unit more structurally safe and beautiful.

[0027] As a preferred technical measure,

[0028] The planetary gear adopts a double gear, which can achieve a higher reduction ratio under the premise of only slightly increasing the weight and volume of the reducer compared to conventional planetary gears;

[0029] The planetary gear carrier and the output flange are fixedly connected, and both parts have shaft shoulders, which are fixedly connected to each other and clamp the output bearing on the output flange; this eliminates the need for additional parts to axially fix the bearing, reduces the number of parts, reduces the weight and volume of the joint unit, and reduces costs.

[0030] As an optimal technical measure, the output bearing adopts a cross roller bearing, which improves the axial force bearing capacity of the output shaft of the joint unit; at least two bearings are set at the three places of the motor rear end cover bearing, the motor base bearing and the center bearing; the motor assembly is an outer rotor permanent magnet motor, which makes the joint structure more compact and the manufacturing process of the motor is simpler and low-cost.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] In the present invention, when the torque transmitted to the ring gear from the output end of the motor rotor or the reducer assembly is greater than the friction torque between the ring gear and the motor base, the ring gear of the reducer assembly will be driven by the motor rotor or the output end of the reducer assembly to overcome the friction torque generated by the friction force generator, so that the ring gear and the motor base rotate relative to each other, thereby achieving friction and slippage between the reducer assembly and the motor base, and limiting the torque borne by the reducer assembly, thereby preventing the reducer itself from being damaged due to the large torque borne from the motor end or the output end of the joint unit, so that the present invention can be applied to a variety of complex working conditions, and the joint components will not be damaged when the joint is subjected to impact loads.

[0033] Further: The joint unit of the present invention has an axial hole, so that the present invention can still achieve a hollow structure under the premise of compact structure and high torque / weight density. It is convenient for hollow wiring or connecting other parts when the joint unit is actually used. At the same time, the cables are assembled inside the joint unit, eliminating the need for external cables, improving the integration of the joint unit, avoiding possible damage to the cables caused by the external environment, and making the joint unit structure safer and more beautiful. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is an overall cross-sectional view of the present invention;

[0035] Figure 2 is an exploded view of the present invention;

[0036] Figure 3It is the overall appearance diagram of the present invention;

[0037] Figure 4 It is an overall cross-sectional view of the friction force generator of the present invention when an active control unit is used.

[0038] Description of reference numerals:

[0039] 1. Motor assembly; 2. Motor encoder; 3. Reducer assembly; 4. Torque limiter assembly; 11. Motor stator and winding; 12. Motor rotor; 13. Motor base; 14. Motor rear end cover; 15. Motor rear end cover bearing; 16. Motor base bearing; 31. Sun gear; 32. Planetary gear; 33. Ring gear; 34. Planetary gear carrier; 35. Output flange; 36. Output bearing; 37. Output bearing end cover; 38. Center bearing; 39. Output encoder; 41. Friction disc; 42. Friction generator; 43. Front end cover. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] On the contrary, the present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention as defined by the claims. Further, in order to make the public have a better understanding of the present invention, some specific details are described in detail in the detailed description of the present invention below. Those skilled in the art can fully understand the present invention without the description of these details.

[0042] like Figure 1-4 As shown, a highly integrated and high-performance robot joint unit includes a motor assembly 1 and a reducer assembly 3 for driving the joint movement. The motor assembly 1 includes a motor rotor 12 for outputting torque and a motor base 13.

[0043] The reducer assembly 3 is provided with a gear ring 33 , and the gear ring 33 is in contact connection with the motor base 13 under the action of the friction force generator 42 .

[0044] When the torque transmitted from the motor rotor 12 or the output end of the reducer assembly 3 to the ring gear 33 is less than the friction torque between the ring gear 33 and the motor base 13, the ring gear 33 of the reducer assembly 3 is fixed on the motor base 13 under the action of the friction torque generated by the friction force generator 42, and the motor rotor 12 drives the output end of the reducer assembly 3 to rotate.

[0045] When the torque transmitted from the motor rotor 12 or the output end of the reducer assembly 3 to the ring gear 33 is greater than the friction torque between the ring gear 33 and the motor base 13, the ring gear 33 of the reducer assembly 3 will overcome the friction torque generated by the friction force generator 42 under the drive of the motor rotor 12 or the output end of the reducer assembly 3, so that the ring gear 33 and the motor base 13 rotate relative to each other. This prevents the reducer itself from being damaged due to the large torque from the motor end or the output end of the joint unit.

[0046] Embodiment of the present invention with additional friction disc 41:

[0047] The gear ring 33 is provided with an annular friction disc 41, and the friction disc 41 is frictionally connected with the motor base 13 or the gear ring 33; the friction disc 41 is made of wear-resistant material; using an independent friction disc 41 is convenient for future maintenance and replacement.

[0048] A specific structural embodiment of the present invention:

[0049] The motor assembly 1 also includes a motor stator and winding 11, and a motor rear end cover 14; the reducer assembly 3 also includes a sun gear 31, a planetary gear 32, a ring gear 33, a planetary gear carrier 34, an output flange 35 and an output bearing end cover 37; the friction disc 41, the friction force generator 42 and the front end cover 43 constitute a torque limiting assembly 4; the motor base 13, the friction disc 41, the ring gear 33, the friction force generator 42 and the front end cover 43 together constitute a friction torque limiting mechanism.

[0050] The friction force generator 42 assembly embodiment of the present invention:

[0051] The motor rotor 12 is inserted into the inner cavity of the motor base 13 , a front end cover 43 is provided on the outer side of the motor base 13 , and the friction force generator 42 is assembled in the accommodating cavity formed by the motor base 13 and the front end cover 43 , and the structure is compact and reliable.

[0052] The front end cover 43 is fixedly connected to the motor base 13, and the friction generator 42 is extruded and assembled in its inner cavity. The friction generator 42 pushes the gear ring 33 so that the gear ring 33 and the motor base 13 are extruded and frictionally matched together; the gear ring 33 has an annular friction surface. The annular friction surface increases the friction area between the gear ring 33 and the friction generator 42 or the motor base 13, reduces wear and improves heat dissipation performance.

[0053] The present invention further provides an encoder embodiment:

[0054] An output encoder 39 with a hollow structure is installed between the planetary gear carrier 34 and the motor base 13; a motor encoder 2 is installed between the motor rotor 12 and the motor base 13; the motor encoder 2 and the output encoder 39 include but are not limited to a magnetic encoder, an inductive encoder, a capacitive encoder, a rotary transformer, and a photoelectric encoder; the output encoder 39 is mainly used to realize real-time angle detection of the output end of the reducer assembly 3 when the ring gear 33 slides frictionally.

[0055] An embodiment of the friction force generator 42 of the present invention:

[0056] The friction force generator 42 is a passive elastic element, including but not limited to a disc spring, a wave spring, and a coil spring, and has a simple and reliable structure.

[0057] Another embodiment of the friction force generator 42 of the present invention:

[0058] The friction force generator 42 is an active control unit, which can generate a squeezing force so that the gear ring 33 and the motor base 13 can be tightly squeezed and frictionally matched together; the active control unit includes but is not limited to an electromagnet and an electrostrictive material. After adopting the active control unit, the friction force generator 42 can dynamically adjust the maximum friction torque between the gear ring 33 and the motor base 13 in real time according to actual needs, so that the joint unit can adapt to various working conditions.

[0059] An embodiment of the present invention to realize hollow wiring:

[0060] The shaft of the motor rotor 12 has a hollow structure; the shaft of the motor rotor 12 is an integral structure with the motor rotor 12 or a separate but fixedly connected structure; the motor encoder 2 has a hollow structure; the sun gear 31 also has a hollow structure, and the sun gear 31 is fixedly connected to the motor rotor 12. This joint unit has a compact structure and a high torque / weight density, and realizes a hollow structure, which is convenient for hollow wiring or connecting other components when the joint unit is actually used.

[0061] An embodiment of the planetary gear 32 of the present invention:

[0062] The planetary gear 32 adopts a double gear, which can achieve a higher reduction ratio under the premise of only slightly increasing the weight and volume of the reducer compared to the conventional planetary gear 32;

[0063] The planetary gear carrier 34 and the output flange 35 are fixedly connected, and both parts have shaft shoulders, which are fixedly connected to each other and clamp the output bearing 36 on the output flange 35; this eliminates the need for additional parts to axially fix the bearing, reduces the number of parts, reduces the weight and volume of the joint unit, and reduces costs.

[0064] Bearing arrangement embodiment of the present invention:

[0065] The output bearing 36 adopts a cross roller bearing, which improves the axial force bearing capacity of the output shaft of the joint unit; at least two bearings are set at the three places of the motor rear end cover bearing 15, the motor base bearing 16 and the center bearing 38; the motor assembly 1 is an outer rotor permanent magnet motor, which makes the joint structure more compact and the manufacturing process of the motor is simpler and low-cost.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A highly integrated and high-performance robot joint unit, comprising a motor assembly (1) for driving the joint movement and a reducer assembly (3), characterized in that: The motor assembly (1) comprises a motor rotor (12) for outputting torque and a motor base (13); The reducer assembly (3) is provided with a gear ring (33), and the gear ring (33) is in contact connection with the motor base (13) under the action of the friction force generator (42); When the torque transmitted from the motor rotor (12) or the output end of the reducer assembly (3) to the ring gear (33) is less than the friction torque between the ring gear (33) and the motor base (13), the ring gear (33) of the reducer assembly (3) is fixed on the motor base (13) under the action of the friction torque generated by the friction force generator (42), and the motor rotor (12) drives the output end of the reducer assembly (3) to rotate; When the torque transmitted from the motor rotor (12) or the output end of the reducer assembly (3) to the ring gear (33) is greater than the friction torque between the ring gear (33) and the motor base (13), the ring gear (33) of the reducer assembly (3) will overcome the friction torque generated by the friction force generator (42) under the drive of the motor rotor (12) or the output end of the reducer assembly (3), so that the ring gear (33) and the motor base (13) rotate relative to each other; The friction force generator (42) is an active control unit that can generate a squeezing force so that the gear ring (33) and the motor base (13) can be tightly squeezed and frictionally matched together; after adopting the active control unit, the friction force generator (42) can dynamically adjust the maximum friction torque between the gear ring (33) and the motor base (13) in real time according to actual needs.

2. A highly integrated and high-performance robot joint unit as claimed in claim 1, characterized in that: The motor rotor (12) is inserted into the inner cavity of the motor base (13), a front end cover (43) is provided on the outer side of the motor base (13), and the friction force generator (42) is assembled in the accommodating cavity formed by the motor base (13) and the front end cover (43).

3. A highly integrated and high-performance robot joint unit as claimed in claim 2, characterized in that: The front end cover (43) is fixedly connected to the motor base (13), and a friction force generator (42) is extruded and assembled in its inner cavity. The friction force generator (42) pushes the gear ring (33) so that the gear ring (33) and the motor base (13) are extruded and frictionally matched together; the gear ring (33) has an annular friction surface.

4. A highly integrated and high-performance robot joint unit as claimed in claim 3, characterized in that: The gear ring (33) is provided with an annular friction disk (41), and the friction disk (41) is frictionally connected to the motor base (13) or the gear ring (33); the friction disk (41) is made of wear-resistant material.

5. A highly integrated and high-performance robot joint unit as claimed in claim 4, characterized in that: An output encoder (39) having a hollow structure is installed between the planetary gear carrier (34) and the motor base (13); a motor encoder (2) is installed between the motor rotor (12) and the motor base (13); the motor encoder (2) and the output encoder (39) include but are not limited to a magnetic encoder, an inductance encoder, a capacitance encoder, a rotary transformer, and a photoelectric encoder; the output encoder (39) is mainly used to realize real-time angle detection of the output end of the reducer assembly (3) when the gear ring (33) is frictionally sliding.

6. A highly integrated and high-performance robot joint unit as claimed in claim 5, characterized in that: The active control unit includes an electromagnet and an electrostrictive material; The motor assembly (1) further comprises a motor stator and winding (11), and a motor rear end cover (14); The reducer assembly (3) further comprises a sun gear (31), a planetary gear (32), a ring gear (33), a planetary gear carrier (34), an output flange (35) and an output bearing end cover (37); The friction disc (41), the friction force generator (42) and the front end cover (43) constitute a torque limiting assembly (4); The motor base (13), the friction disk (41), the gear ring (33), the friction force generator (42) and the front end cover (43) together constitute a friction torque limiting mechanism.

7. A highly integrated and high-performance robot joint unit as claimed in claim 6, characterized in that: The shaft of the motor rotor (12) has a hollow structure; the shaft of the motor rotor (12) is integrally arranged with the motor rotor (12) or is a separate but fixedly connected structure; the motor encoder (2) has a hollow structure; the sun gear (31) also has a hollow structure, and the sun gear (31) is fixedly connected to the motor rotor (12).

8. A highly integrated and high-performance robot joint unit as claimed in claim 7, characterized in that: The planetary gear (32) is a double gear; The planetary gear carrier (34) and the output flange (35) are fixedly connected, and both have shaft shoulders, which are fixedly connected to each other and clamp the output bearing (36) on the output flange (35).

9. A highly integrated and high-performance robot joint unit as claimed in claim 8, characterized in that: The output bearing (36) is a cross roller bearing; at least two bearings are provided at the motor rear end cover bearing (15), the motor base bearing (16) and the center bearing (38); and the motor assembly (1) is an outer rotor permanent magnet motor.

Images