Robot motion joint

Abstract

The utility model relates to a robot motion joint which comprises a motor fixed on a base and a rotating shaft overhung from a motor rotor, a movable joint is fixed on the rotating shaft, and the motor rotor moves to drive the movable joint fixedly arranged on the rotating shaft to move; the bearing is arranged between the rotating shaft and the base, a bearing inner ring of the bearing sleeves the rotating shaft, a bearing outer ring of the bearing is fixed on the base, and the bearing can bear an axial load and a radial load between the bearing inner ring and the bearing outer ring. According to the anti-impact joint mechanism, the bearing is additionally arranged between the motor and the movable joint, the bearing transmits impact from the movable joint to the base, the motor is prevented from being directly impacted, the problem that the motor is frequently damaged due to impact in the operation process of a robot is solved, and the service life of the motor can be effectively prolonged.

Description

Technical Field

[0001] This utility model relates to the field of motion joint technology, specifically to a robot motion joint. Background Technology

[0002] Humanoid robots are robotic products that possess typical human characteristics, can adapt to complex environments, and perform multi-task operations. They represent the pinnacle of the robotics field, and their overall development and component breakthroughs will drive the rapid development of upstream and downstream industrial chains. Currently, the most common driving device for humanoid robots is the rotary electric drive joint system, which has advantages such as high torque density and light weight, effectively enhancing the robot's mobility. Its lower limb structure typically consists of several rotary drive motors arranged at the hip joint, thigh, and lower leg. The thigh and lower leg, and the lower leg and foot, are connected by bearings and other rotating pairs, and then through a linkage structure, with different motors driving the thigh, lower leg, and foot structures to rotate independently. Through specific motion planning and control, this set of rotary drive motors can enable the humanoid robot to achieve balanced standing, walking, and other behaviors, simulating human movements to the greatest extent possible, and even surpassing human capabilities.

[0003] Humanoid robots currently represented by companies such as Logic Robotics, Unitree Robotics G1, Beijing Tiangong, and Shanghai Qinglong all feature lower limb rotary motors whose rotor outputs are directly connected to the legs or linkages. During walking, the reaction force from the feet hitting the ground is transmitted to the rotary motors via joint linkages. This design means that the impact force from the feet acts directly on the motor's rotor, reducer, or flexspline. The harsh operating conditions of the robot cause this ground impact force to be transmitted irregularly and frequently, significantly shortening the lifespan of the rotary motors and increasing operating costs. Therefore, there is significant room for improvement in the motion mechanisms of humanoid robots. There is an urgent need to design a joint impact-resistant structure to isolate the force transmission between the motor and the joints to a certain extent, thereby increasing the overall impact resistance and durability of the robot. Utility Model Content

[0004] In view of the problem that existing robot joint mechanisms cannot effectively buffer the impact force transmitted to the drive motor, thus reducing the service life of the rotary motor, this utility model provides a robot motion joint.

[0005] This application provides a robot motion joint, including a motor fixed on a base, a rotating shaft extending from the motor rotor, and a movable joint fixed on the rotating shaft. The movement of the motor rotor drives the movable joint fixed on the rotating shaft to move.

[0006] The bearing is positioned between the shaft and the base. The inner ring of the bearing is fitted onto the shaft, and the outer ring of the bearing is fixed to the base. The bearing can withstand axial loads and radial loads between the inner and outer rings.

[0007] Preferably, the rotating shaft has a circumferentially protruding retaining ring on one side of the bearing inner ring, and one side of the bearing inner ring abuts against the retaining ring; the inner retaining ring is sleeved on the rotating shaft and abuts against the other side of the bearing inner ring.

[0008] Preferably, a limiting platform is formed on one side of the bearing outer ring, which is higher than the mounting surface of the bearing outer ring, and one side of the bearing outer ring abuts against the limiting platform; an outer retaining ring is fixed on the base on the other side of the bearing outer ring.

[0009] Preferably, the outer retaining ring has at least one limiting block on the side facing the movable joint, and a circumferentially protruding protrusion is formed on the movable joint; during the rotation of the movable joint, the protrusion and the limiting block can contact each other when rotating at a preset angle, thereby limiting the rotation angle of the movable joint.

[0010] Preferably, the base is provided with at least two limiting blocks around the rotation center, and a limiting space is formed between the two limiting blocks; a circumferentially protruding protrusion is formed on the movable joint; during the rotation of the movable joint, the movement range of the protrusion is limited to the limiting space, thereby restricting the range of motion of the movable joint.

[0011] Preferably, the bearing is a crossed roller bearing.

[0012] The impact-resistant joint mechanism in this design incorporates a bearing between the motor and the movable joint. The bearing transmits the impact from the movable joint to the base, preventing the motor from being directly impacted. This solves the problem of frequent motor damage due to impacts during robot operation and effectively extends the motor's service life. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the robot's movable joint after being cut across the base in three parts;

[0014] Figure 2 for Figure 1 A magnified view of a portion of the image;

[0015] Figure 3 This is an axial explosion diagram of the bearing 5 of this utility model;

[0016] Figure 4 This is a partial schematic diagram of the bearing 5 of this utility model after being cut along the shaft;

[0017] Figure 5 This is a schematic diagram of the robot's movable joint from another angle after being cut across the base 3 parts.

[0018] In the picture:

[0019] 1: Motor; 2: Movable joint; 21: Protrusion; 3: Base; 31: Limiting platform; 32: Outer retaining ring; 321: Limiting block; 3211: Limiting space; 4: Rotating shaft; 41: Limiting ring; 42: Inner retaining ring; 5: Bearing; 51: Inner ring of bearing; 52: Outer ring of bearing. Detailed Implementation

[0020] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. In this specification, the dimensions of the drawings do not represent the actual dimensions. They are only used to illustrate the relative positional and connection relationships between the components. Components with the same name or the same reference numeral represent similar or identical structures and are limited to illustrative purposes.

[0021] Figure 1 and Figure 2 This is a schematic diagram of the robot's motion joint according to this application. It has a motor 1 fixed to the robot's base 3, and the motor 1 has a rotating shaft 4 extending from the motor rotor. A movable joint 2 is fixed to the rotating shaft 4. When the motor is running, the movement of the motor rotor drives the movable joint 2 fixed to the rotating shaft 4 to move, thus enabling the robot's limb movement.

[0022] Typically, in existing technology, the rotating shaft 4 is not connected to the base 3; the rotating shaft 4 is directly connected to the motor rotor of the motor 1 and the movable joint 2. In this case, external impacts on the movable joint 2 during movement will act directly on the motor rotor through the rotating shaft 4, thus the motor rotor will bear direct impact.

[0023] exist Figure 2 The robot motion joint of this application also includes a bearing 5 disposed between the rotating shaft 4 and the base 3. The inner ring 51 of the bearing 5 is fixedly sleeved on the rotating shaft 4, and the outer ring 52 of the bearing 5 is fixed on the base 3. The bearing 5 can withstand the axial load and radial load between its inner and outer rings. In this case, when the movable joint 2 is impacted, the impact transmitted to the rotating shaft 4 is transmitted to the base 3 by the bearing 5. Therefore, the external impact from the movable joint 2 will eventually be transmitted to the base 3 and absorbed by the base 3 and the robot body fixed thereto. The impact is transmitted to the internal motion mechanism of the motor 1 with little or no impact. Therefore, under this design, the motion impact borne by the moving parts inside the motor 1 is reduced, thereby effectively extending the service life of the motor 1. When the robot joint is subjected to impact load, the axial and radial impact forces are transmitted to the crossed roller bearing through the inner retaining ring and then to the stator flange, so that the impact force perfectly avoids the motor rotor, improving the motor's applicability, meeting performance requirements, and extending its service life.

[0024] Figure 3The diagram illustrates the installation of bearing 5. The rotating shaft 4 has a circumferentially protruding retaining ring 41 on one side of the bearing inner ring 51, with one side of the bearing inner ring 51 abutting against the retaining ring 41. An inner retaining ring 42 is fitted onto the rotating shaft 4 and abuts against the other side of the bearing inner ring 51. The inner retaining ring 42 is fixed to the rotating shaft 4 by interference fit or mechanical fixation, thus axially limiting the bearing inner ring 51. A retaining platform 31, higher than the mating surface, is formed on one side of the bearing outer ring 52 on the base 3, with one side of the bearing outer ring 52 abutting against the retaining platform 31. An outer retaining ring 32 is fixed to the base 3 on the other side of the bearing outer ring 52, thereby axially limiting the bearing outer ring 52. The radial limitation of the bearing inner ring 51 is achieved by its fitting onto the rotating shaft 4; similarly, the radial limitation of the bearing outer ring 52 is achieved by its embedding into the surface of the base 3.

[0025] Furthermore, at least one limiting block 321 is formed on the side of the outer retaining ring 32 facing the movable joint 2, and correspondingly, a circumferentially protruding protrusion 21 is formed on the movable joint 2. During the rotation of the movable joint 2, the protrusion 21 and the limiting block 321 can contact each other when rotating at a certain angle, thereby limiting the rotation angle of the movable joint 2. Figure 4 As shown, preferably, the outer retaining ring 3 has at least two limiting blocks 321 arranged around the rotation center, and the space between the two limiting blocks 321 forms a limiting space 3211. Due to the restriction of the limiting blocks 321, the movement range of the protrusion 21 is limited to the interior of the limiting space 3211, thus mechanically restricting the range of motion of the movable joint 2. The outer retaining ring can serve as a limit for the crossed roller bearing and also as a limit for the robot joint, allowing the robot joint to rotate within a limited angular range, reducing the danger of motor runaway to a certain extent. It can also be used for measuring joint angles and calibrating the initial 0 position.

[0026] The bearing 5 is preferably a crossed roller bearing. In the embodiment of this application, the bearing 5 is an IKOCRBS 508 high-rigidity crossed roller bearing with SD of 50mm, D of 66mm, B of 8mm, dynamic load of 4900N, and static load of 6170N. The motor 1 is a Little Elephant high-performance planetary gear rotary motor with a maximum outer diameter of 100mm and a maximum torque of 330Nm.

[0027] Crossed roller bearings are compact bearings with orthogonally arranged rollers between the inner and outer rings. The rolling surfaces have line contact, resulting in minimal elastic displacement due to load, and they can simultaneously bear complex loads such as radial, axial, and torque loads. This particular bearing is a high-rigidity crossed roller bearing with both inner and outer rings being a single, non-split structure, minimizing installation errors and offering high precision and rigidity. Furthermore, a separator is installed between the rollers, ensuring smooth rotation and making it suitable for high-speed applications. This bearing is widely used in rotating parts of industrial robots, machine tools, and medical equipment requiring small size, high rigidity, and high rotational precision.

[0028] The crossed roller bearing consists of a shaft and inner retaining ring that are slidably fitted together to form an assembly. The motor and base are assembled together with screws. The outer retaining ring and base are fastened with screws. The movable joint and shaft are fastened with circumferential screws.

[0029] Crossed roller bearings are compact bearings with orthogonally arranged rollers between the inner and outer rings. The rolling surfaces have line contact, resulting in minimal elastic displacement due to load, and they can simultaneously bear complex loads such as radial, axial, and torque loads. This particular bearing is a high-rigidity crossed roller bearing with both inner and outer rings being a single, non-split structure, minimizing installation errors and offering high precision and rigidity. Furthermore, a separator is installed between the rollers, ensuring smooth rotation and making it suitable for high-speed applications. This bearing is widely used in rotating parts of industrial robots, machine tools, and medical equipment requiring small size, high rigidity, and high rotational precision. The outer retaining ring serves as a limit for the crossed roller bearing and also as a limit for robot joints, ensuring the robot joints rotate within a defined angular range, reducing the risk of motor runaway, and can also be used for measuring joint angles and calibrating initial zero positions.

[0030] The robot's movable joint in this application transmits impact to the base 3 via a bearing 5 located between the base 3 and the rotating shaft 4, avoiding direct transmission of impact to the motor and thus mitigating the negative impact of external impact on the motor. The bearing 5 in this mechanism can also resist axial force, radial force, and overturning moment, and provides mechanical limiting. This mechanism can serve as a motor support for any joint of the robot, facilitating motor torque output. The impact-resistant joint mechanism in this design incorporates a crossed roller bearing between the rotary motor and the robot joint. This crossed roller bearing absorbs 100% of the impact force, solving the problem of frequent motor damage due to impacts during robot operation and increasing the overall impact resistance and durability of the robot.

[0031] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the scope of the present utility model. Any modifications and improvements made to the technical solution of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A robot motion joint, characterized in that, Includes a motor (1) fixed on a base (3), a rotating shaft (4) extending from the motor rotor, and a movable joint (2) fixed on the rotating shaft (4). The movement of the motor rotor drives the movable joint (2) fixed on the rotating shaft (4) to move. The bearing (5) is located between the rotating shaft (4) and the base (3). The inner ring (51) of the bearing (5) is sleeved on the rotating shaft (4), and the outer ring (52) of the bearing (5) is fixed on the base (3). The bearing (5) can withstand the axial load and radial load between the inner ring (51) and the outer ring (52).

2. The robot motion joint as described in claim 1, characterized in that, The rotating shaft (4) has a circumferentially protruding retaining ring (41) on one side of the bearing inner ring (51), and one side of the bearing inner ring (51) abuts against the retaining ring (41); the inner retaining ring (42) is sleeved on the rotating shaft (4) and abuts against the other side of the bearing inner ring (51).

3. The robot motion joint as described in claim 1, characterized in that, The base (3) forms a limiting platform (31) on one side of the bearing outer ring (52) that is higher than the mounting surface of the bearing outer ring (52), and one side of the bearing outer ring (52) abuts against the limiting platform (31); the base (3) fixes the outer retaining ring (32) on the other side of the bearing outer ring (52).

4. The robot motion joint as described in claim 3, characterized in that, The outer retaining ring (32) has at least one limiting block (321) on the side facing the movable joint (2), and a circumferentially protruding protrusion (21) is formed on the movable joint (2); during the rotation of the movable joint (2), the protrusion (21) and the limiting block (321) can contact each other when rotating at a preset angle, thereby limiting the rotation angle of the movable joint (2).

5. The robot motion joint as described in claim 3, characterized in that, The base (3) is provided with at least two limiting blocks (321) around the rotation center, and a limiting space (3211) is formed between the two limiting blocks (321); a circumferentially protruding protrusion (21) is formed on the movable joint (2); during the rotation of the movable joint (2), the range of motion of the protrusion (21) is limited to the limiting space (3211), thereby limiting the range of motion of the movable joint (2).

6. The robot motion joint as described in claim 1, characterized in that, The bearing (5) is a crossed roller bearing.

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