A mechanical arm based on planetary roller screw drive

Abstract

The application discloses a mechanical arm based on planetary roller screw driving, and relates to the technical field of mechanical arms, which comprises a first arm rod, a second arm rod, a driving mechanism, a planetary roller screw pushing mechanism and a pitching joint; the end portions of the first arm rod and the second arm rod are connected through the pitching joint, the driving mechanism is installed on the first arm rod, the driving mechanism is connected with the pitching joint through the planetary roller screw pushing mechanism, and the driving mechanism is used for driving the second arm rod to perform a pitching action relative to the first arm rod through the planetary roller screw pushing mechanism and the pitching joint. The mechanical arm based on planetary roller screw driving provided by the application can ensure high bearing and high precision, realize compactness and light weight of the mechanical arm, reduce energy consumption, and improve motion flexibility.

Description

Technical Field

[0001] This invention relates to the field of robotic arm technology, and in particular to a robotic arm based on planetary roller screw drive. Background Technology

[0002] Robotic arms, with their advantages of low cost, high efficiency, and good safety, have been widely deployed in fields such as fire rescue, industrial manufacturing, military security, space exploration, and medical rehabilitation. However, as applications extend to complex and special environments, robotic arms must not only ensure their own functionality but also overcome multiple constraints related to size, weight, power, and precision imposed by stringent conditions.

[0003] Traditional robotic arms mostly use hydraulic transmission, which, while enabling large-space, long-distance, and high-load operations, results in bulky equipment, slow movement, and insufficient control precision. Conventional motor-driven industrial robotic arms, in large-space, long-distance conditions, experience a sharp increase in the torque and inertia required by the joints (especially the pitch joint) as the lever arm lengthens. This forces a corresponding increase in the size and weight of the motor and reducer, leading to a bulky overall arm structure, increased weight, high energy consumption, and a significant decrease in flexibility. These shortcomings severely restrict the robotic arm's ability to balance load-bearing capacity and motion performance in special environments. Summary of the Invention

[0004] The purpose of this invention is to provide a robotic arm based on planetary roller screw drive to solve the problems existing in the prior art. While ensuring high load capacity and high precision, it can achieve compactness and lightweighting of the robotic arm, reduce energy consumption, and improve motion flexibility.

[0005] To achieve the above objectives, the present invention provides the following solution: The present invention provides a robotic arm based on planetary roller screw drive, including a first arm, a second arm, a drive mechanism, a planetary roller screw pushing mechanism, and a pitch joint; The ends of the first boom and the second boom are connected by the pitch joint. The drive mechanism is mounted on the first boom and is connected to the pitch joint through the planetary roller screw push mechanism. The drive mechanism is used to drive the second boom to pitch relative to the first boom through the planetary roller screw push mechanism and the pitch joint. The drive mechanism includes a drive motor, a bearing housing, and a thrust bearing. The planetary roller screw pushing mechanism includes a screw, a planetary roller nut, and a pushing sleeve. The thrust bearing is installed in the bearing housing and fixedly connected to the screw. The screw can rotate in the bearing housing via the thrust bearing. The drive motor is fixedly connected to the bearing housing. The bearing housing is rotatably connected to the first arm. The output end of the drive motor is connected to the screw, enabling torque to be transmitted to the screw. The planetary roller nut and the screw are connected by multiple planetary rollers to form a planetary roller screw pair. The planetary roller nut is fixedly connected to the pushing sleeve. The end of the screw away from the drive motor passes through the pushing sleeve. The pitch joint includes two joint assemblies symmetrically arranged on both sides of the first boom. Each joint assembly includes a main boom link, a secondary boom link, a triangular link, and a straight link. One end of the main boom link is fixed to the first boom, and the other end is rotatably connected to one end of the secondary boom link. The other end of the secondary boom link is fixed to the second boom. A main boom link cam is fixed on the main boom link and is located between the two ends of the main boom link. The first corner of the triangular link is rotatably connected to the main boom link cam. A secondary boom link cam is fixed on the secondary boom link and is located between the two ends of the secondary boom link. The second corner of the triangular link is rotatably connected to one end of the straight link, and the other end of the straight link is rotatably connected to the secondary boom link cam. The third triangular part of the triangular link is hinged to the end of the push sleeve away from the planetary roller nut.

[0006] In one embodiment, the main boom link is fixedly connected to the first boom link by bolts, and the auxiliary boom link is fixedly connected to the second boom link by bolts.

[0007] In one embodiment, a bearing housing fixing plate is fixedly connected to the first arm, and the bearing housing is rotatably connected to the bearing housing fixing plate.

[0008] In one embodiment, the thrust bearing is a double-direction thrust angular contact ball bearing.

[0009] In one embodiment, an end cam is fixedly provided at the end of the auxiliary boom link, and the end cam is rotatably connected in the end shaft hole of the main boom link through rollers and their retainers.

[0010] In one embodiment, the main boom connecting rod cam is rotatably connected to the first corner shaft hole of the first corner of the triangular connecting rod via rollers and their retainers.

[0011] In one embodiment, the two ends of the straight connecting rod are provided with straight connecting rod shaft holes, the second corner of the triangular connecting rod is fixedly provided with a second corner convex shaft, the second corner convex shaft is rotatably connected in the straight connecting rod shaft hole at one end of the straight connecting rod, and the auxiliary arm connecting rod convex shaft is rotatably connected in the straight connecting rod shaft hole at the other end of the straight connecting rod.

[0012] In one embodiment, a hinge ring is fixedly connected to the end of the push sleeve away from the planetary roller nut, and the third triangular portion of the triangular link is provided with a third corner connection hole. The hinge ring is connected to the second triangular portion connection hole of the two triangular links through a plug screw and a nut.

[0013] The present invention achieves the following technical effects compared to the prior art: The robotic arm based on planetary roller screw drive provided by this invention uses a planetary roller screw structure as the core transmission element. Leveraging its high power density, it achieves high thrust output within a very small volume, thereby significantly reducing the size and weight of the drive system, making the robotic arm compact and lightweight. This reduces inertial and gravitational loads during movement, thus lowering energy consumption and improving energy efficiency. Utilizing the high rigidity and high precision of the planetary roller screw, it achieves high load-bearing capacity while ensuring motion accuracy and stability, meeting the needs of precision operations. Through modular design and multi-link pitch joint design, the robotic arm's motion flexibility is improved, enabling it to adapt to the operational needs of complex unstructured environments, achieving continuous operation in large spaces and obstacle avoidance in complex spaces. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of a robotic arm based on planetary roller screw drive in an embodiment of the present invention; Figure 2 This is a side view of the robotic arm in its stored state according to an embodiment of the present invention, based on planetary roller screw drive. Figure 3 This is a schematic diagram of the deployed state of the robotic arm based on planetary roller screw drive in an embodiment of the present invention. Figure 4 This is an exploded structural diagram of the drive mechanism, planetary roller screw pushing mechanism, and first arm in an embodiment of the present invention. Figure 5 This is an exploded structural diagram of a robotic arm based on planetary roller screw drive in an embodiment of the present invention. Figure 6 This is an exploded structural diagram of the joint assembly in an embodiment of the present invention.

[0016] In the diagram: 1-First boom, 2-Second boom, 3-Drive mechanism, 4-Planetary roller screw pushing mechanism, 5-Pitch joint, 6-Drive motor, 7-Bearing housing, 8-Thrust bearing, 9-Screw, 10-Planetary roller nut, 11-Pushing sleeve, 12-Main boom link, 13-Second boom link, 14-Triangular link, 15-Straight link, 16-Main boom link cam shaft, 17-First corner, 18 - Auxiliary arm connecting rod cam, 19-Second corner, 20-Third corner, 21-Bearing seat fixing plate, 22-End cam, 23-Bearing retaining ring, 24-End cover, 25-Roller, 26-Cage, 27-End shaft hole, 28-First corner shaft hole, 29-Straight connecting rod shaft hole, 30-Second corner cam, 31-Hinge ring, 32-Third corner connecting hole, 33-Flat key, 34-Connecting flange. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The purpose of this invention is to provide a robotic arm based on planetary roller screw drive to solve the problems existing in the prior art. While ensuring high load capacity and high precision, it can achieve compactness and lightweighting of the robotic arm, reduce energy consumption, and improve motion flexibility.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] like Figures 1-6 As shown, this embodiment provides a robotic arm based on planetary roller screw drive, including a first arm 1, a second arm 2, a drive mechanism 3, a planetary roller screw pushing mechanism 4, and a pitch joint 5; The ends of the first arm 1 and the second arm 2 are connected by a pitch joint 5. The drive mechanism 3 is mounted on the first arm 1. The drive mechanism 3 is connected to the pitch joint 5 through a planetary roller screw pushing mechanism 4. It is used to drive the second arm 2 to pitch relative to the first arm 1 through the planetary roller screw pushing mechanism 4 and the pitch joint 5. The drive mechanism 3 includes a drive motor 6, a bearing housing 7, and a thrust bearing 8. The planetary roller screw pushing mechanism 4 includes a screw 9, a planetary roller nut 10, and a pushing sleeve 11. The thrust bearing 8 is installed in the bearing housing 7 and is fixedly connected to the screw 9. The screw 9 can rotate in the bearing housing 7 through the thrust bearing 8. The drive motor 6 is fixedly connected to the bearing housing 7. The bearing housing 7 is rotatably connected to the first arm 1. The axial reaction force of the pushing sleeve 11 on the screw 9 can be transmitted to the first arm 1 through the bearing housing 7 via the thrust bearing 8. The output end of the drive motor 6 is connected to the screw 9. The torque is transmitted to the screw 9 through the flat key 33, causing the screw 9 to rotate. The planetary roller nut 10 and the screw 9 are connected by multiple planetary rollers to form a planetary roller screw pair. The planetary roller nut 10 is fixedly connected to the pushing sleeve 11. The end of the screw 9 away from the drive motor 6 passes through the pushing sleeve 11. The pitch joint 5 includes two joint assemblies symmetrically arranged on both sides of the first arm 1. Each joint assembly includes a main arm link 12, a secondary arm link 13, a triangular link 14, and a straight link 15. One end of the main arm link 12 is fixed to the first arm 1, and the other end is rotatably connected to one end of the secondary arm link 13. The other end of the secondary arm link 13 is fixed to the second arm 2. A main arm link cam 16 is fixedly mounted on the main arm link 12, located between the two ends of the main arm link 12. The first corner portion 17 of the angle link 14 is rotatably connected to the main arm link cam 16. The auxiliary arm link cam 18 is fixedly provided on the auxiliary arm link 13. The auxiliary arm link cam 18 is located between the two ends of the auxiliary arm link 13. The second corner portion 19 of the triangular link 14 is rotatably connected to one end of the straight link 15. The other end of the straight link 15 is rotatably connected to the auxiliary arm link cam 18. The third triangular portion 20 of the triangular link 14 is hinged to the end of the push sleeve 11 away from the planetary roller nut 10.

[0021] The thrust bearing 8 is fixed to the end of the lead screw 9 away from the planetary roller nut 10 via the bearing housing 7, the bearing retaining ring 23, and the end cover 24. The thrust bearing 8 is a double-direction thrust angular contact ball bearing. The end cover 24 is fixed to the bearing housing 7 with screws. The end of the lead screw 9 passes through the inner ring of the thrust bearing 8. The inner ring of the thrust bearing 8 is fixed between the lead screw shoulder and the bearing retaining ring 23 by threading the bearing retaining ring 23 at the end of the lead screw 9. The outer ring of the thrust bearing 8 is fixed by the end cover 24. The outer ring of the thrust bearing 8 is fixed between the bearing housing shoulder and the end cover 24 by the end cover 24. The output end of the drive motor 6 is fixed to the connecting flange 34 by bolts. The connecting flange 34 is fitted with the lead screw 9. The torque is transmitted by the flat key 33. The drive motor 6 and the bearing housing 7 are fixed by set bolts. The planetary roller nut 10 and the push sleeve 11 are fastened by bolts to transmit thrust. During operation, the drive motor 6 drives the lead screw 9 to rotate. The rotational motion of the lead screw 9 is converted into the linear motion of the planetary roller nut 10 via a planetary roller screw pair. This, in turn, drives the push sleeve 11 to move along the lead screw 9. The push sleeve 11 acts on the triangular connecting rod 14, thereby driving the second arm 2 to perform a pitching motion relative to the first arm 1 via the multi-link pitch joint 5. This robotic arm can be folded and retracted in a "C" shape, and can perform pitching motions from 0 to 180°.

[0022] The main boom link 12 is fixedly connected to the first boom 1 by bolts, and the auxiliary boom link 13 is fixedly connected to the second boom 2 by bolts.

[0023] A bearing seat fixing plate 21 is fixedly connected to the first arm 1. The bearing seat fixing plate 21 is fixed to the first arm 1 by bolts, and the bearing seat 7 is rotatably connected to the bearing seat fixing plate 21.

[0024] The end of the auxiliary boom link 13 is fixedly provided with an end cam 22, which is rotatably connected to the end shaft hole 27 of the main boom link 12 through rollers 25 and their retainers 26. The main boom link cam 16 is rotatably connected to the first corner shaft hole 28 of the first corner portion 17 of the triangular link 14 through rollers 25 and their retainers 26.

[0025] The two ends of the straight connecting rod 15 are provided with straight connecting rod shaft holes 29. The second corner portion 19 of the triangular connecting rod 14 is fixedly provided with a second corner convex shaft 30. The second corner convex shaft 30 is rotatably connected in the straight connecting rod shaft hole 29 at one end of the straight connecting rod 15. The auxiliary arm connecting rod convex shaft 18 is rotatably connected in the straight connecting rod shaft hole 29 at the other end of the straight connecting rod 15.

[0026] A hinge ring 31 is fixedly connected to one end of the push sleeve 11 away from the planetary roller nut 10. The third triangular part 20 of the triangular link 14 is provided with a third triangular part connection hole 32. The hinge ring 31 is connected to the third triangular part connection hole 32 of the two triangular links 14 through a plug screw and a nut. The push sleeve 11 is ball-jointed to the two triangular links 14 through the hinge ring 31.

[0027] This invention uses a planetary roller screw push mechanism in conjunction with a pitch joint to drive the second arm to pitch relative to the first arm, converting the rotational motion of the screw into high-thrust linear push, which greatly reduces the driving torque required in the pitch direction, eliminates the need for a high-torque pitch motor, reduces the requirements for the drive motor, and thus reduces the size and weight of the drive system and the whole machine, making the robotic arm lighter and more compact.

[0028] The planetary roller screw of this invention has the advantages of high load-bearing capacity, high transmission accuracy, good rigidity, and long service life, which enables the robotic arm to have high pitch motion control accuracy and good reliability, and can withstand greater loads, while ensuring the accuracy and stability of the motion; compared with hydraulic transmission, it also has the advantages of low noise and low maintenance cost.

[0029] The multi-segment robotic arm of this invention is driven by a planetary roller screw and can be folded and stored. It has a large working space, low energy consumption, and flexible movement. It can realize continuous operation in large spaces and obstacle avoidance in complex spaces, and adapt to unstructured complex environments.

[0030] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A robotic arm based on planetary roller screw drive, characterized in that: It includes a first boom, a second boom, a drive mechanism, a planetary roller screw push mechanism, and a pitch joint; The ends of the first boom and the second boom are connected by the pitch joint. The drive mechanism is mounted on the first boom and is connected to the pitch joint through the planetary roller screw push mechanism. The drive mechanism is used to drive the second boom to pitch relative to the first boom through the planetary roller screw push mechanism and the pitch joint. The drive mechanism includes a drive motor, a bearing housing, and a thrust bearing. The planetary roller screw pushing mechanism includes a screw, a planetary roller nut, and a pushing sleeve. The thrust bearing is installed in the bearing housing and fixedly connected to the screw. The screw can rotate in the bearing housing via the thrust bearing. The drive motor is fixedly connected to the bearing housing. The bearing housing is rotatably connected to the first arm. The output end of the drive motor is connected to the screw, enabling torque to be transmitted to the screw. The planetary roller nut and the screw are connected by multiple planetary rollers to form a planetary roller screw pair. The planetary roller nut is fixedly connected to the pushing sleeve. The end of the screw away from the drive motor passes through the pushing sleeve. The pitch joint includes two joint assemblies symmetrically arranged on both sides of the first boom. Each joint assembly includes a main boom link, a secondary boom link, a triangular link, and a straight link. One end of the main boom link is fixed to the first boom, and the other end is rotatably connected to one end of the secondary boom link. The other end of the secondary boom link is fixed to the second boom. A main boom link cam is fixed on the main boom link and is located between the two ends of the main boom link. The first corner of the triangular link is rotatably connected to the main boom link cam. A secondary boom link cam is fixed on the secondary boom link and is located between the two ends of the secondary boom link. The second corner of the triangular link is rotatably connected to one end of the straight link, and the other end of the straight link is rotatably connected to the secondary boom link cam. The third triangular part of the triangular link is hinged to the end of the push sleeve away from the planetary roller nut.

2. The robotic arm based on planetary roller screw drive according to claim 1, characterized in that: The main boom link is fixedly connected to the first boom link by bolts, and the auxiliary boom link is fixedly connected to the second boom link by bolts.

3. The robotic arm based on planetary roller screw drive according to claim 1, characterized in that: A bearing seat fixing plate is fixedly connected to the first arm, and the bearing seat is rotatably connected to the bearing seat fixing plate.

4. The robotic arm based on planetary roller screw drive according to claim 1, characterized in that: The thrust bearing is a double-direction thrust angular contact ball bearing.

5. The robotic arm based on planetary roller screw drive according to claim 1, characterized in that: The end of the auxiliary boom link is fixedly provided with an end convex shaft, which is rotatably connected to the end shaft hole of the main boom link through rollers and their retainers.

6. The robotic arm based on planetary roller screw drive according to claim 1, characterized in that: The main boom connecting rod cam is rotatably connected to the first corner shaft hole of the first corner of the triangular connecting rod via rollers and their retainers.

7. The robotic arm based on planetary roller screw drive according to claim 1, characterized in that: The two ends of the straight connecting rod are provided with straight connecting rod shaft holes, and the second corner of the triangular connecting rod is fixedly provided with a second corner convex shaft. The second corner convex shaft is rotatably connected in the straight connecting rod shaft hole at one end of the straight connecting rod, and the auxiliary arm connecting rod convex shaft is rotatably connected in the straight connecting rod shaft hole at the other end of the straight connecting rod.

8. The robotic arm based on planetary roller screw drive according to claim 1, characterized in that: The end of the push sleeve away from the planetary roller nut is fixedly connected to a hinge ring, and the third triangular part of the triangular link is provided with a third corner connection hole. The hinge ring is connected to the second triangular part connection hole of the two triangular links through a plug screw and a nut.

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