A linear joint for a humanoid robot

Abstract

A linear joint for a humanoid robot, wherein a tension pressure sensor (1) is used as an end cover, and the functions of two parts are realized by one part, thereby reducing the number of parts, improving the compactness of the mechanism, and reducing the weight of the whole machine; a bearing pressure cover (14) is located at the right end of a planetary roller screw shaft (13) and is sealed by a seal, and the end cover seals the left end of the planetary roller screw shaft, thereby achieving sealing of the entire planetary roller screw shaft; an encoder rotor (3) is directly fastened to a planetary roller screw nut (8) by an encoder screw (4), and the planetary roller screw nut and a motor rotor (5) are fixedly connected, the motor rotor drives the planetary roller screw nut to rotate, and the planetary roller screw nut drives the encoder rotor to rotate, thereby reducing the transmission clearance of the intermediate component, achieving better rotation accuracy and rotation coaxiality, and thus improving the position accuracy of the linear joint.

Description

Technical Field

[0001] The present invention relates to the technical field of humanoid robots, and in particular to a linear joint used for a humanoid robot. Background Art

[0002] A humanoid robot (English: Android), also known as a bionic man, is a robot designed to mimic human appearance and behavior. It specifically refers to a type with a human-like body. Until recently, the concept of humanoid robots was a science fiction concept, often seen in movies, television, comics, novels, etc. Today, advances in robotics have made it possible to design functional, realistic humanoid robots.

[0003] Modern humanoid robots are intelligent robots, such as the ROBOT·X humanoid robot, which has up to 17 servos in each movable joint of the machine, with 17 degrees of freedom, which is very flexible and can complete difficult actions such as swinging the arm back 90 degrees. It is also equipped with a well-designed control system, which can automatically complete the whole set of actions through its own intelligent programming software.

[0004] With the development of humanoid robots, the torque density of traditional rotational joints is difficult to further improve, and the demand for new linear joints in the robotics field is further increasing.

[0005] However, the existing technical solutions do not consider the sealing problem of the linear joint, and the radial runout of the planetary roller screw shaft causes the crushing failure problem. The radial runout of the encoder rotor is large, which will lead to low recognition accuracy or loss of data read by the encoder stator, etc. The tension and pressure sensor is not highly integrated and heavy, which leads to a heavy weight of the robot's power module, reducing the application scenarios and working conditions of the robot. Summary of the invention

[0006] In order to overcome the defects of the prior art, the technical problem to be solved by the present invention is to provide a linear joint for a humanoid robot, which reduces the number of components, improves the compactness of the mechanism, reduces the weight of the whole machine, can seal the planetary roller screw shaft, and improves the recognition accuracy of the encoder.

[0007] The technical solution of the present invention is: the linear joint for a humanoid robot comprises: a planetary roller screw shaft, a planetary roller screw roller, a tension and pressure sensor, an encoder, and a motor;

[0008] The roller of the planetary roller screw is sleeved on the left side of the planetary roller screw shaft, the planetary roller screw nut is sleeved on the planetary roller screw shaft and the planetary roller screw roller, and a motor is arranged outside the planetary roller screw nut, the motor includes a motor rotor, a motor stator, a motor sleeve, and a motor cover plate, a deep groove ball bearing and a four-point contact ball bearing are sleeved on the left and right sides of the planetary roller screw nut respectively, the bearing gland is on the right end of the planetary roller screw shaft and is sealed by a seal, an encoder is arranged on the left end of the planetary roller screw shaft, the encoder includes an encoder stator, an encoder rotor, and an encoder screw, and the encoder is fixed on the left side of the motor cover plate The encoder stator and the planetary roller screw nut have a protrusion on the left end face, and the central axis of the protrusion has a threaded hole. The encoder rotor is directly fastened to the planetary roller screw nut through the encoder screw. The planetary roller screw nut and the motor rotor are fixedly connected. The motor rotor drives the planetary roller screw nut to rotate, and the planetary roller screw nut drives the encoder rotor to rotate. The tension pressure sensor serves as an end cover to seal the left end of the planetary roller screw shaft. At the left end, the tension pressure sensor and the screw bearing seat are fixedly connected by locking screws, and at the right end, the bearing cover and the screw bearing seat are fixedly connected by locking screws.

[0009] The tension and pressure sensor of the present invention serves as an end cover, and the functions of two parts are realized by one part, thereby reducing the number of parts, improving the compactness of the mechanism, and reducing the weight of the whole machine; the bearing cover is at the right end of the planetary roller screw shaft and is sealed by a seal, and the end cover seals the left end of the planetary roller screw shaft, thereby being able to achieve sealing of the entire planetary roller screw shaft; the encoder rotor is directly fastened to the planetary roller screw nut by an encoder screw, and the planetary roller screw nut and the motor rotor are fixedly connected, the motor rotor drives the planetary roller screw nut to rotate, and the planetary roller screw nut drives the encoder rotor to rotate, thereby reducing the transmission clearance of the intermediate piece, achieving better rotation accuracy and rotation coaxiality, and thus improving the recognition accuracy of the encoder. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Schematic diagram of the overall structure of a linear joint for a humanoid robot according to the present invention.

[0011] Figure 2 Schematic diagram of the structure of the planetary roller screw nut according to the present invention.

[0012] Figure 3 It is a schematic diagram of the axial floating clearance of the linear joint of the humanoid robot according to the present invention, in which part of the structure is deleted. DETAILED DESCRIPTION

[0013] 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 specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0014] In order to make the description of the present disclosure more detailed and complete, the following provides an illustrative description of the implementation and specific embodiments of the present invention; however, this is not the only form of implementing or using the specific embodiments of the present invention. The implementation covers the features of multiple specific embodiments and the method steps and sequences used to construct and operate these specific embodiments. However, other specific embodiments can also be used to achieve the same or equivalent functions and step sequences.

[0015] like Figure 1 As shown, the linear joint for a humanoid robot comprises: a planetary roller screw shaft 13, a planetary roller screw roller 7, a tension and pressure sensor 1, an encoder, and a motor;

[0016] The planetary roller screw roller is sleeved on the left side of the planetary roller screw shaft, the planetary roller screw nut 8 is sleeved on the planetary roller screw shaft and the planetary roller screw roller, and a motor is arranged outside the planetary roller screw shaft, the motor includes a motor rotor 5, a motor stator 6, a motor sleeve 9, a motor cover 18, a deep groove ball bearing 20, and a four-point contact ball bearing 12 are sleeved on the left and right sides of the planetary roller screw nut, respectively, the bearing pressure cover 14 is at the right end of the planetary roller screw shaft and is sealed by a seal, and an encoder is arranged at the left end of the planetary roller screw shaft, the encoder includes an encoder stator 2, an encoder rotor 3, an encoder screw 4, and a motor cover. The encoder stator is fixed on the left side, and there is a protrusion on the left end face of the planetary roller screw nut. The central axis of the protrusion has a threaded hole. The encoder rotor is directly fastened to the planetary roller screw nut through the encoder screw. The planetary roller screw nut and the motor rotor are fixedly connected. The motor rotor drives the planetary roller screw nut to rotate, and the planetary roller screw nut drives the encoder rotor to rotate. The tension pressure sensor serves as an end cover to seal the left end of the planetary roller screw shaft. At the left end, the tension pressure sensor and the screw bearing seat 23 are fixedly connected by locking screws 15, and at the right end, the bearing cover and the screw bearing seat are fixedly connected by locking screws.

[0017] The tension and pressure sensor of the present invention serves as an end cover, and the functions of two parts are realized by one part, thereby reducing the number of parts, improving the compactness of the mechanism, and reducing the weight of the whole machine; the bearing cover is at the right end of the planetary roller screw shaft and is sealed by a seal, and the end cover seals the left end of the planetary roller screw shaft, thereby being able to achieve sealing of the entire planetary roller screw shaft; the encoder rotor is directly fastened to the planetary roller screw nut by an encoder screw, and the planetary roller screw nut and the motor rotor are fixedly connected, the motor rotor drives the planetary roller screw nut to rotate, and the planetary roller screw nut drives the encoder rotor to rotate, thereby reducing the transmission clearance of the intermediate piece, achieving better rotation accuracy and rotation coaxiality, and thus improving the recognition accuracy of the encoder.

[0018] Preferably, a polytetrafluoroethylene sleeve 10 is nested inside the bearing gland, which can improve the radial rigidity of the planetary roller screw shaft, reduce radial deformation, and reduce axial friction.

[0019] Preferably, the bearing gland is internally embedded with a skeleton oil seal 11, which is fixed in the bearing gland via a sealing baffle 16. The skeleton oil seal is used to achieve sliding sealing, has a good dynamic sealing effect, and increases the sealing life. The skeleton oil seal can also be replaced by a general sealing ring.

[0020] Preferably, the four-point contact ball bearing is a four-point contact ball bearing or a double-row angular contact ball bearing, both of which have similar effects and are used to bear larger axial loads.

[0021] Preferably, the left end of the inner ring of the four-point contact ball bearing is tightly attached to the axial end boss 81 of the planetary roller screw nut, the right end of the inner ring is locked by a locking nut 17, the left side of the outer ring of the four-point contact ball bearing is tightly attached to the inner boss 91 of the motor sleeve, and the right side of the outer ring is pressed by a bearing cover, and the bearing cover is fastened by a locking screw.

[0022] Preferably, the electronic stator and the motor sleeve are clamped by the axial positioning boss 51 and fastened with glue.

[0023] Preferably, if Figure 2 As shown, two shaft retaining ring grooves 82 are provided on the planetary roller screw nut, and the inner ring of the deep groove ball bearing is clamped in the shaft retaining ring groove by the shaft retaining ring 19. One end of the motor sleeve is used for radial support through the motor cover, and the encoder stator is fixed on the left side of the motor cover, and the outer ring of the deep groove ball bearing is fixed on the right side. The inner ring of the deep groove ball bearing is fixed on the planetary roller screw nut, and the inner ring of the deep groove ball bearing is clamped by two shaft retaining ring grooves. And the outer ring of the deep groove ball bearing is floating in the axial direction (such as Figure 3 As shown in the figure, the arrow indicates the axial floating clearance), which can reduce axial vibration, simplify the structure, improve reliability, reduce the axial force of the deep groove ball bearing, and thus increase the service life of the bearing.

[0024] Preferably, a needle roller bearing 22 or a joint ball bearing is arranged in the screw bearing seat. The needle roller bearing can withstand large push and pull forces. The needle roller bearing can be replaced by a joint ball bearing, so that the effect of using two linear joints in parallel can be achieved, and the joint ball bearing can withstand push and pull forces in multiple directions.

[0025] Preferably, an anti-loosening washer 21 is provided at the locking screw to achieve mechanical anti-loosening.

[0026] The beneficial effects of the present invention are as follows:

[0027] 1. The tension and pressure sensor and the end cover of the linear joint are made into an integrated part, so that the whole machine is lighter, compact and easy to install. The bearing gland of the four-point contact bearing is used to fix the polytetrafluoroethylene sleeve and the skeleton oil seal. One structural part can achieve multiple uses at the same time, reducing the number of parts. One end of the planetary roller screw nut and the rotor of the encoder are fixed by a screw, reducing the number of intermediate adapters, improving coaxiality and accuracy, and reducing weight.

[0028] 2. The inner ring of the deep groove ball bearing is clamped by a shaft retaining ring to prevent axial movement. At the same time, the outer ring of the deep groove ball bearing is axially floating. In this way, even if the planetary roller screw nut is axially deformed by a large external force, it will not generate a large axial destructive force on the deep groove ball bearing, thereby causing the deep groove ball bearing to fail.

[0029] 3. A polytetrafluoroethylene sleeve is added to the sliding end of the planetary roller screw shaft, which can improve the radial stiffness of the planetary roller screw shaft and reduce radial deformation while keeping the axial friction small. Polytetrafluoroethylene is very light and has less friction than ordinary sliding bearings.

[0030] 4. The planetary roller screw shaft adopts a skeleton oil seal to achieve sliding sealing, which has good dynamic sealing effect and increases the sealing life.

[0031] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A linear joint for a humanoid robot, characterized in that: It includes: Planetary roller screw shaft (13), planetary roller screw roller (7), tension and pressure sensor (1), encoder, motor; The roller of the planetary roller screw is sleeved on the left side of the planetary roller screw shaft, the planetary roller screw nut (8) is sleeved on the planetary roller screw shaft and the planetary roller screw roller, and a motor is arranged outside the planetary roller screw shaft, the motor comprises a motor rotor (5), a motor stator (6), a motor sleeve (9), and a motor cover plate (18), a deep groove ball bearing (20) and a four-point contact ball bearing (12) are sleeved on the left and right sides of the planetary roller screw nut, respectively, a bearing pressure cover (14) is at the right end of the planetary roller screw shaft and is sealed by a sealing member, and an encoder is arranged at the left end of the planetary roller screw shaft, the encoder comprises an encoder stator (2), an encoder rotor (3), and an encoder nut (4). The encoder stator is fixed on the left side of the motor cover plate. The left end face of the planetary roller screw nut has a protrusion, and the central axis of the protrusion has a threaded hole. The encoder rotor is directly fastened to the planetary roller screw nut through the encoder screw. The planetary roller screw nut and the motor rotor are fixedly connected. The motor rotor drives the planetary roller screw nut to rotate, and the planetary roller screw nut drives the encoder rotor to rotate. The tension pressure sensor serves as an end cover to seal the left end of the planetary roller screw shaft. The tension pressure sensor and the screw bearing seat (23) are fixedly connected at the left end by a locking screw (15), and the bearing pressure cover and the screw bearing seat are fixedly connected at the right end by a locking screw.

2. The linear joint for a humanoid robot according to claim 1, characterized in that: A polytetrafluoroethylene sleeve (10) is nested inside the bearing gland.

3. The linear joint for a humanoid robot according to claim 2, characterized in that: A skeleton oil seal (11) is nested inside the bearing gland, and the skeleton oil seal is fixed inside the bearing gland via a sealing baffle (16).

4. The linear joint for a humanoid robot according to claim 3, characterized in that: The four-point contact ball bearing is a four-point contact ball bearing or a double-row angular contact ball bearing.

5. The linear joint for a humanoid robot according to claim 4, characterized in that: The left end of the inner ring of the four-point contact ball bearing is tightly attached to the shaft end boss (81) of the planetary roller screw nut, the right end of the inner ring is locked by a locking nut (17), the left side of the outer ring of the four-point contact ball bearing is tightly attached to the inner boss (91) of the motor sleeve, the right side of the outer ring is pressed by a bearing cover, and the bearing cover is fastened by a locking screw.

6. The linear joint for a humanoid robot according to claim 5, characterized in that: The motor stator and the motor sleeve are clamped by an axial positioning boss (51) and fastened with glue.

7. The linear joint for a humanoid robot according to claim 6, characterized in that: Two shaft retaining ring grooves (82) are arranged on the planetary roller screw nut, and the inner ring of the deep groove ball bearing is clamped in the shaft retaining ring grooves through a shaft retaining ring (19).

8. The linear joint for a humanoid robot according to claim 7, characterized in that: A needle bearing (22) or a joint ball bearing is arranged in the screw bearing seat.

9. The linear joint for a humanoid robot according to claim 8, characterized in that: An anti-loosening washer (21) is provided at the locking screw.

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