Robot motion joint

Abstract

The invention 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] The present invention relates to the technical field of motion joints, and in particular to a motion joint of a robot. Background Art

[0002] Humanoid robots refer to robot products that have typical human characteristics, can adapt to complex environments and perform multi-task operations. They are the epitome of the field of robots. The research and development of complete machines and parts will drive the rapid development of the upstream and downstream industrial chains. At present, the most common humanoid robot drive device is a rotary electric drive joint system, which has the advantages of high torque density and light structure weight, and can effectively improve the robot's mobility. The lower limb structure is generally a group of several rotary drive motors arranged in the hip joint, thigh and calf, respectively. The thigh and calf, and the calf and sole are connected by bearings and other rotating pairs, and then through the connecting rod structure, different motors drive the thigh, calf and sole structures to rotate independently. Through specific motion planning and control, this group of rotary drive motors can realize the balanced standing, walking and other behaviors of humanoid robots, simulate humans to the greatest extent, and even surpass human athletic ability.

[0003] The current representative products of humanoid robots include Zhiyuanyuanzheng, Yushu G1, Beijing Tiangong, Shanghai Qinglong, etc. The output end of the rotor of their lower limb rotary motor is directly connected to the thigh, leg or connecting rod. During the robot's walking process, the reaction force of the foot touching the ground will be transmitted to the rotary motor through the joint connecting rod. Such a design will cause the impact force from the foot to directly act on the rotor, reducer or flexible wheel of the motor. The harsh working conditions of the robot will cause the impact force of touching the ground to be irregular and frequently transmitted, greatly shortening the service life of the rotary motor and increasing the cost of use. Therefore, the motion mechanism of the humanoid robot has huge room for improvement, and it is urgent to design a joint impact-resistant structure to isolate the force transmission between the motor and the joint to a certain extent, and increase the impact resistance and durability of the whole machine. Summary of the invention

[0004] In view of the problem that the existing robot joint mechanism cannot effectively buffer the impact force transmitted to the driving motor, thereby reducing the service life of the rotating motor, the present invention provides a robot motion joint.

[0005] The present application provides a robot motion joint, comprising a motor fixed on a base, a rotating shaft extending from a motor rotor, a movable joint fixed on the rotating shaft, and the movement of the motor rotor drives the movable joint fixed on the rotating shaft to move; The bearing is arranged between the rotating shaft and the base, the inner ring of the bearing is sleeved on the rotating shaft, the outer ring of the bearing is fixed on the base, and the bearing can bear the axial load and radial load between the inner ring and the outer ring of the bearing.

[0006] Preferably, the rotating shaft has a circumferentially protruding limiting ring on one side of the bearing inner ring, and one side of the bearing inner ring abuts against the limiting ring; the inner stop ring is sleeved on the rotating shaft and abuts against the other side of the bearing inner ring.

[0007] Preferably, a limit platform higher than the bearing outer ring mounting surface is formed on one side of the bearing outer ring on the base, and one side of the bearing outer ring abuts against the limit platform; an outer retaining ring is fixed on the base on the other side of the bearing outer ring.

[0008] Preferably, at least one limit block is formed on the side of the outer retaining ring facing the movable joint, forming a circumferentially protruding protrusion on the movable joint; during the rotation of the movable joint, the protrusion and the limit block can contact when rotating to a preset angle, thereby limiting the rotation angle of the movable joint.

[0009] Preferably, the base is provided with at least two limit blocks around the rotation center, and a limit space is formed between the two limit 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 limit space, thereby limiting the movement range of the movable joint.

[0010] Preferably, the bearing is a crossed roller bearing.

[0011] The impact-resistant joint mechanism of this design adds bearings between the motor and the movable joint. The bearings transfer the impact from the movable joint to the base, avoiding direct impact on the motor. This solves the problem of frequent damage to the motor due to impact during the operation of the robot and can effectively extend the operating life of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the movable joint of the robot of the present invention after the base 3 is partially cut away; Figure 2 It is a schematic diagram of an axial explosion of the bearing 5 of the present invention; Figure 3 It is a partial schematic diagram of the bearing 5 of the present invention after being cut along the axis; Figure 4 It is a schematic diagram of another angle of the robot movable joint of the present invention after the base 3 is partially cut away.

[0013] In the figure: 1: motor; 2: movable joint; 21: protrusion; 3: base; 31: limit platform; 32: outer retaining ring; 321: limit block; 3211: limit space; 4: rotating shaft; 41: limit ring; 42: inner retaining ring; 5: bearing; 51: bearing inner ring; 52: bearing outer ring. DETAILED DESCRIPTION

[0014] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. In this specification, the size ratios in the drawings do not represent the actual size ratios, but are only used to reflect the relative position relationship and connection relationship between the components. Components with the same name or the same number represent similar or identical structures and are only for illustrative purposes.

[0015] Figure 1 The schematic diagram of the structure of the robot motion joint of the present application has a motor 1 fixed on the base 3 of the robot, the motor 1 has a rotating shaft 4 extending from the motor rotor, and the movable joint 2 is fixed on the rotating shaft 4. When the motor is running, the movement of the motor rotor drives the movable joint 2 fixed on the rotating shaft 4 to move to realize the limb movement of the robot.

[0016] Generally, in the prior art, the rotating shaft 4 is not connected to the base 3, and the rotating shaft 4 is directly connected to the motor rotor of the motor 1 and the movable joint 2. In this case, the external impact received by the movable joint 2 during the movement will directly act on the motor rotor through the rotating shaft 4, so the motor rotor will be directly impacted.

[0017] exist Figure 1 The robot motion joint of the present application also includes a bearing 5 arranged 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 is fixed on the base 3. The bearing 5 can withstand the axial load and radial load between its inner ring and outer ring. 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 almost not or less transmitted to the motion mechanism inside the motor 1. Therefore, under such a design, the motion impact borne by the moving parts inside the motor 1 is also reduced, thereby effectively extending the operating life of the motor 1. When the robot joint is subjected to an impact load, the axial and radial impact forces will be transmitted to the cross roller bearing through the inner retaining ring, and then transmitted to the stator flange, so that the impact force perfectly avoids the motor rotor, improves the applicability of the motor, meets performance requirements, and extends the service life.

[0018] Figure 2: is a schematic diagram of the installation of the bearing 5. The rotating shaft 4 has a circumferentially protruding limit ring 41 on one side of the bearing inner ring 51, and one side of the bearing inner ring 51 abuts against the limit 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. The inner retaining ring 42 is fixed on the rotating shaft 4 by interference fit or mechanical fixation to achieve axial limitation of the bearing inner ring 51. The base 3 forms a limit platform 31 higher than the matching surface on one side of the bearing outer ring 52, and one side of the bearing outer ring 52 abuts against the limit platform 31. The outer retaining ring 32 is fixed on 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 sleeve on the rotating shaft 4. Similarly, the radial limitation of the bearing outer ring 52 is achieved by its surface embedded in the base 3.

[0019] Furthermore, at least one stopper 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 stopper 321 may contact each other when the movable joint 2 rotates to a certain angle, thereby limiting the rotation angle of the movable joint 2. Figure 3 As shown, preferably, the outer retaining ring 3 is provided with at least two limit blocks 321 around the rotation center, and the space between the two limit blocks 321 forms a limit space 3211. Due to the limitation of the limit blocks 321, the movement range of the protrusion 21 is limited to the inside of the limit space 3211, thereby mechanically limiting the range of motion of the movable joint 2. The outer retaining ring can be used as a limiter for the cross roller bearing or as a limiter for the robot joint, so that the robot joint can rotate and operate within a limited angle range, reducing the risk of motor loss of control to a certain extent, and can also be used for measuring the joint angle and calibrating the initial 0 position.

[0020] The bearing 5 is preferably a cross roller bearing. In the embodiment of the present application, the bearing 5 is selected as an IKOCRBS 508 high rigidity cross roller bearing, with SD of 50 mm, D of 66 mm, B of 8 mm, dynamic load of 4900 N, and static load of 6170 N. The motor 1 is selected as a small elephant high performance planetary gear rotary motor, with a maximum outer diameter of 100 mm and a maximum torque of 330 Nm.

[0021] Crossed roller bearings are compact bearings with rollers arranged orthogonally between the inner and outer rings. The rolling surfaces are in line contact, so the elastic displacement caused by the bearing load is extremely small, and it can simultaneously carry complex loads such as radial loads, axial loads, and moments. This type of bearing is a high-rigidity crossed roller bearing, with an integral structure (non-split) for the inner and outer rings, which is not prone to installation errors, high precision, and high rigidity. In addition, a separator is installed between the rollers, which rotates smoothly and is suitable for parts with higher rotation speeds. This type of bearing is widely used in rotating parts of industrial robots, machine tools, and medical equipment that require small, high rigidity and high rotation accuracy.

[0022] The cross roller bearing, the rotating shaft and the inner retaining ring are installed into an assembly through sliding, the motor and the base are installed into an assembly through screws, the outer retaining ring and the base are fastened by screws, and the movable joint and the rotating shaft are fastened by circumferential screws.

[0023] Crossed roller bearings are compact bearings with rollers arranged orthogonally between the inner and outer rings. The rolling surfaces are in line contact, so the elastic displacement caused by the bearing load is extremely small, and it can simultaneously carry complex loads such as radial loads, axial loads, and torque. This type of bearing is a high-rigidity crossed roller bearing, with both inner and outer rings in an integrated structure (non-split), which is not prone to installation errors, high precision, and high rigidity. In addition, a separator is installed between the rollers, which rotates smoothly and is suitable for parts with higher speeds. This type of bearing is widely used in rotating parts of industrial robots, machine tools, and medical equipment that require small, high rigidity and high rotation accuracy. The outer retaining ring can be used as a limiter for the crossed roller bearing or for the robot joint, so that the robot joint can rotate and operate within a limited angle range, which reduces the danger of motor loss of control to a certain extent. It can also be used to measure the joint angle and calibrate the initial zero position.

[0024] The robot movable joint of the present application transmits the impact to the base 3 through the bearing 5 arranged between the base 3 and the rotating shaft 4, avoiding the impact from being directly transmitted to the inside of the motor, thereby offsetting the negative impact of the external impact force on the motor. The bearing 5 in the mechanism can also resist axial force, radial force, overturning bending moment, and realize mechanical limit. The mechanism can be used as a motor bracket for any joint of the robot to facilitate the output of motor torque. The impact-resistant joint mechanism of the present design adds a cross roller bearing between the rotating motor and the robot joint. The cross roller bearing replaces the motor to withstand 100% of the impact force, solves the problem that the motor is often damaged by impact during the operation of the robot, and increases the impact resistance and durability of the whole machine.

[0025] The above content only describes the preferred implementation mode of the present invention, and does not limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solution of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A robot motion joint, characterized in that: It comprises a motor (1) fixed on a base (3), a rotating shaft (4) cantilevered from the motor rotor, and a movable joint (2) fixed on the rotating shaft (4), wherein the movement of the motor rotor drives the movable joint (2) fixed on the rotating shaft (4) to move; The bearing (5) is arranged between the rotating shaft (4) and the base (3); the inner ring (51) of the bearing (5) is sleeved on the rotating shaft (4); the outer ring (52) of the bearing (5) is fixed on the base (3); and the bearing (5) can bear the axial load and radial load between the inner ring (51) and the outer ring (52).

2. The robot motion joint according to claim 1, characterized in that: The rotating shaft (4) has a circumferentially protruding limiting ring (41) on one side of the bearing inner ring (51), and one side of the bearing inner ring (51) abuts against the limiting 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 according to claim 1, characterized in that: A limiting platform (31) is formed on one side of the bearing outer ring (52) and 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); an outer retaining ring (32) is fixed on the other side of the bearing outer ring (52) on the base (3).

4. The robot motion joint according to claim 3, characterized in that: At least one limiting block (321) is formed on the side of the outer retaining ring (32) 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 the movable joint (2) rotates to a preset angle, thereby limiting the rotation angle of the movable joint (2).

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

6. The robot motion joint according to claim 1, characterized in that: The bearing (5) is a cross roller bearing.

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