A two-degree-of-freedom coaxial nested three-stage electric telescopic rotary joint structure

Abstract

The application discloses a two-degree-of-freedom coaxial nested three-stage electric telescopic rotary joint structure, which comprises a base end, a three-stage coaxial sleeve assembly and a terminal manipulator, the base and the base sleeve are hinged to form a pitch degree of freedom, and the sleeve axial telescopic constitutes a linear degree of freedom. The mechanism is provided with multiple groups of mechanical transmission chains, all driving sources are arranged on the base, four groups of three-axis bevel gear pairs are used for distributing torque, and the pitch, three-stage synchronous telescopic and three-degree-of-freedom movement of the manipulator are driven respectively. The telescopic transmission adopts a double-wire rod symmetrical structure, the middle sleeve and the end sleeve are synchronously linked and extended, the terminal manipulator is integrated with a wrist rotation, pitch and palm rotation three-axis bevel gear transmission chain. The extension section is free of motors, sensors and other electronic elements, can realize large-stroke telescopic and terminal attitude independent / linkage adjustment, is suitable for special working conditions such as high temperature and narrow channel, has the advantages of high coaxiality, good rigidity, strong reliability and simple control decoupling, and is suitable for aerospace and limit environment maintenance grabbing equipment.

Description

Technical Field

[0001] This invention relates to the field of electric actuators and linear transmission joint technology, specifically to a two-degree-of-freedom coaxial nested three-stage electric telescopic rotary joint structure. It is particularly suitable for automated equipment that needs to extend from a fixed base into confined spaces or restricted passages and adjust its end effector posture in real time. Through its three-stage coaxial nested sleeve configuration, it achieves a large-stroke linear extension and retraction several times the length of the base within a limited radial envelope dimension, thus enabling a single joint to complete tasks such as reaching different spatial positions and changing the orientation of tools or grippers. Background Technology

[0002] In specialized scenarios, the end effector often needs to extend from a fixed position on its base through a narrow channel, reaching a target area far from the entrance, and adjusting its posture upon arrival to perform actions such as gripping, tightening, inspection, or cleaning. This requires the actuator to have long-stroke linear extension and retraction capabilities, as well as the ability to rotate around its own axis to flexibly adjust the orientation of the end effector. Furthermore, in extreme temperatures and other environments, electronic components are highly susceptible to failure; therefore, the extended portion of the actuator should ideally avoid housing motors, sensors, or circuit boards to fundamentally improve survivability and mission reliability in harsh environments. In addition, due to the extremely limited size of the operating window or equipment hatch, such actuators must achieve all of the above functions within an extremely compact radial envelope space.

[0003] Currently, a common solution for achieving long-stroke telescopic and rotary linkage is to mechanically connect standard electric actuators, ball screw slides, and other linear actuators with independent rotary joints and slewing mechanisms. While this combination is structurally intuitive and easy to select, it inevitably leads to an overall longer axial dimension, insufficient cantilever support stiffness, and the need for separate sets of drives and cables, increasing the number of pipelines and the installation volume. When needing to pass through narrow entrances for internal operations, the series structure struggles to simultaneously meet the requirements of radial compactness and a long telescopic ratio. In a few engineering practices, integrated designs have emerged that nest the rotary drive within the telescopic cylinder; however, due to the complexity of the internal transmission chain and the design difficulty of the stroke amplification mechanism, only short telescopic strokes are often achievable, and the accuracy and reliability of multi-stage synchronous telescopic movement are difficult to guarantee, still failing to meet the application requirements of a large telescopic ratio and high rotational accuracy.

[0004] Therefore, to meet the integrated requirements of long-stroke telescopic and rotary posture adjustment in special environments, there is an urgent need for a new type of electric telescopic actuator with a compact structure, large telescopic ratio, minimal electronic components, and drive components concentrated in the base. This mechanism should, while ensuring that the radial dimension is determined only by the outermost sleeve, achieve linear displacement several times the length of the base through the synchronous extension of multiple sleeves. Simultaneously, it should achieve continuous end-effector rotation via coaxial rotary transmission and easily integrate position detection elements to improve motion accuracy and repeatability, thus providing a highly integrated and reliable linear-rotary transmission joint solution for aerospace, extreme environment operations, and other applications. Summary of the Invention

[0005] The purpose of this invention is to address the deficiencies in the existing technology by providing a two-degree-of-freedom coaxial nested three-stage electrically operated telescopic rotary joint structure.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A two-degree-of-freedom coaxial nested three-stage electrically operated telescopic rotary joint structure includes: a base end, a sleeve assembly, and a manipulator. The bottom of the base tube of the sleeve assembly is hinged to the base end to form the first degree of freedom of the telescopic rotary joint structure. The sleeve assembly extends and retracts along its axial direction to form the second degree of freedom of the telescopic rotary joint structure. The sleeve assembly includes a base tube (first stage), a middle tube (second stage), and an end tube (third stage) nested sequentially, and the middle tube and the end tube are synchronously linked and controlled to extend and retract relative to the base tube. A manipulator is provided at the upper end of the end tube. The rotating and transmission mechanism is located within the telescopic rotating joint structure and includes a rotating mechanism and a transmission mechanism; the first and second stage telescopic mechanisms are located between the base cylinder and the middle cylinder; the second and third stage telescopic mechanisms are located between the middle cylinder and the end cylinder. The rotation and transmission mechanism, the first and second level telescopic mechanism, and the second and third level telescopic mechanism are coaxially nested and connected in series to form a three-level sleeve coaxial configuration; the rotation mechanism is used to drive the entire sleeve assembly to rotate around its own axis; the transmission mechanism is used to transmit the torque of the lower power output end of the base (this torque includes the transmission chain torque that controls the extension and retraction of the sleeve, and also includes the transmission chain torque that controls the adjustment of each degree of freedom of the manipulator) upwards step by step within the telescopic and rotary joint structure, so that the torque at the bottom is transmitted to the first and second level telescopic mechanism and the second and third level telescopic mechanism and finally to the manipulator; The telescopic rotary joint structure is equipped with multiple independent mechanical transmission chains, including a pitch transmission chain that controls the bending adjustment of the sleeve assembly relative to the base end, and a telescopic transmission chain that controls the linear extension and retraction of the sleeve assembly. The rotational motion and the linear extension and retraction motion are controlled by independent drive sources, and the two transmission chains do not interfere with each other in structure, so as to realize independent action or linkage control of extension and rotation.

[0007] Furthermore, the robotic hand comprises three degrees of freedom: a wrist rotation section, a wrist pitch section, and a palm rotation section. The wrist rotation section is rotatably mounted on the top of the end cylinder, and the wrist pitch section is rotatably mounted on the wrist rotation section and allows for controlled pitch angle adjustment relative to it. It is understood that the rotation axis of the wrist pitch section is perpendicular to the rotation axis of the wrist rotation section. The palm rotation section is rotatably mounted on the wrist pitch section and is equipped with grippers. The mechanical transmission chain also includes a wrist rotation transmission chain, a wrist pitch transmission chain, and a palm rotation transmission chain.

[0008] Furthermore, the base end and the base cylinder are hinged together by a base main shaft. The base end has a base platform inside, and the base cylinder has a base cylinder platform inside. The pitch transmission chain includes a helical gear drive shaft, a helical gear driven shaft, a lower connecting rod, and an upper connecting rod. The helical gear drive shaft is rotatably arranged along the inner axis of the base end. A helical gear driven shaft is meshed on one side of the helical gear drive shaft, and the two shafts are arranged perpendicular to each other. The lower end of the lower connecting rod is fixedly connected to the helical gear driven shaft, and the upper end is hinged to the upper connecting rod. The upper end of the upper connecting rod is hinged to the outer wall of the base cylinder. The pitch transmission chain also includes a power input shaft and a first bevel gear mounted on the base platform. The power input shaft has four shafts and drives the four first bevel gears to rotate accordingly. The base platform has four primary driven shafts that rotate, and each primary driven shaft has a second bevel gear at its lower end. The base main shaft is rotatably equipped with four third bevel gears, and each third bevel gear is meshed with a first bevel gear and a second bevel gear on both sides to form four sets of three-axis bevel gear pairs. The lower end of the middle cylinder is slidably inserted into the base cylinder, and the lower end of the middle cylinder is fixedly provided with a lower platform. The lower end of the end cylinder is slidably inserted into the middle cylinder, and the lower end of the end cylinder is fixedly provided with a lower platform.

[0009] Furthermore, the telescopic transmission chain includes a first mandrel, a first lead screw shaft, and a second lead screw shaft. The first mandrel and the first lead screw shaft are rotatably disposed within the base cylinder, and the second lead screw shaft is rotatably disposed within the middle cylinder. A first lead screw nut is provided on the lower platform of the middle cylinder. The first lead screw shaft and the first lead screw nut are threadedly connected to form a "linear motor." The rotation of the first lead screw shaft controls the telescopic adjustment of the middle cylinder relative to the base cylinder. The first mandrel is a mandrel that slides inside the second lead screw shaft, and the two are connected by a sliding spline (i.e., the first mandrel transmits power to drive the rotation of the outer second lead screw shaft, and the second lead screw shaft can slide axially relative to the first mandrel, with circumferential limitation and axial sliding between them). A second lead screw nut is fixedly provided on the lower platform of the end cylinder. The second lead screw shaft and the second lead screw nut are threadedly connected to form a "linear motor," which drives the telescopic adjustment of the end cylinder sequentially through: first mandrel → second lead screw shaft → second lead screw nut → end cylinder.

[0010] Furthermore, one of the aforementioned three-axis bevel gear pairs (as shown in the attached diagram) Figure 2 , 3 The output end of the third group of three-axis bevel gears (shown from left to right) has a seventh helical gear on the base cylinder platform. This seventh helical gear drives two symmetrical first spindle rods and two first lead screw shafts through gear meshing. The symmetrical double lead screw configuration avoids lateral bending moments in the multi-stage sleeves and prevents sleeve misalignment and jamming. Two helical gear shafts mesh with both sides of the seventh helical gear, and each of these shafts meshes with a sixth helical gear. The sixth helical gear is followed by a fifth helical gear. The sixth helical gear drives the first lead screw shaft to rotate, and the fifth helical gear drives the first spindle rod to rotate. Specifically, the lower end of the first lead screw shaft is equipped with a sixth helical gear... The lower end is rotatably mounted on the base cylinder platform, and the upper end of the first lead screw shaft is screwed to the first lead screw nut mounted on the lower platform of the middle cylinder. The lower end of the first mandrel rod is provided with a fifth helical gear, and the lower end is rotatably mounted on the base cylinder platform. Since the fifth helical gear meshes with the sixth helical gear, the gear meshing transmission path of the telescopic transmission chain on the base cylinder platform is: seventh helical gear → two helical gear shafts → two sixth helical gears → two fifth helical gears. Since the sixth helical gear meshes with the fifth helical gear, when the seventh helical gear rotates, it can simultaneously drive the first lead screw shaft and the first mandrel rod to rotate, that is, it can realize the synchronous linkage telescopic control of the middle cylinder and the end cylinder.

[0011] Furthermore, the wrist rotation part includes a U-shaped frame rotatably disposed on the upper end of the end tube. The lower end of the U-shaped frame extends into the end tube and is provided with a wrist base gear along the axial direction. The wrist pitching part and the palm rotation part are disposed in the U-shaped opening of the U-shaped frame. The wrist pitching part includes an inner wrist horizontal axis, an L-shaped frame, and a first bevel gear. The inner wrist horizontal axis is transversely disposed between the two side walls of the U-shaped frame. The first bevel gear is fixedly disposed on one side of the L-shaped frame and both are rotatably disposed on the inner wrist horizontal axis. A second bevel gear is rotatably disposed on the other side of the L-shaped frame. The palm rotation part is disposed on the second bevel gear. A third bevel gear is rotatably disposed on the inner wrist horizontal axis. The third bevel gear meshes with the second bevel gear. Inside the U-shaped frame and coaxial with the wrist base gear, there are a core bevel gear and a sleeve bevel gear. The sleeve bevel gear meshes with the first bevel gear, and the core bevel gear meshes with the third bevel gear (the second bevel gear and the core bevel gear mesh with the second bevel gear on both sides of the third bevel gear respectively, which also constitutes a three-axis bevel gear pair structure).

[0012] The end cylinder is rotatably equipped with a third drive shaft, a second spindle, and a sleeve cylinder. The second spindle is rotatably mounted inside the sleeve cylinder. A sleeve bevel gear is connected to the upper end of the sleeve cylinder, and a sleeve spur gear is connected to the lower end. A spindle bevel gear is connected to the upper end of the second spindle, and a spindle spur gear is connected to the lower end. The upper end of the third drive shaft meshes with a wrist base gear, and the lower end is equipped with a second gear. The second gear, the spindle spur gear, and the sleeve spur gear are all rotatably mounted within the lower platform of the end cylinder.

[0013] Furthermore, one of the aforementioned three-axis bevel gear pairs (as shown in the attached diagram) Figure 2 , 3 The output end of the second group of three-axis bevel gears (shown from left to right) has a fourth helical gear on the base cylinder platform. The wrist rotation transmission chain is driven by a fourth helical gear meshing with the first-stage wrist rotation shaft. The first-stage wrist rotation shaft meshes with the second-stage wrist rotation shaft through the shaft end, and the second-stage wrist rotation shaft meshes with the third-stage wrist rotation shaft through the shaft end. The third-stage wrist rotation shaft drives the wrist base gear.

[0014] Furthermore, one of the aforementioned three-axis bevel gear pairs (as shown in the attached diagram) Figure 2 , 3 The output end of the first group of three-axis bevel gear pairs (shown from left to right) is connected to the wrist pitch stage shaft. The wrist pitch transmission chain consists of a primary wrist pitch shaft that meshes with a secondary wrist pitch shaft at its shaft end. The secondary wrist pitch shaft then meshes with a sleeve at its shaft end, which in turn meshes with a first bevel gear.

[0015] Furthermore, one of the aforementioned three-axis bevel gear pairs (as shown in the attached diagram) Figure 2 , 3 The output end of the third-axis bevel gear pair (the fourth group from left to right) is connected to the first-stage shaft that rotates the palm. The palm rotation transmission chain consists of a primary palm rotation shaft that meshes with the secondary palm rotation shaft at its shaft end, the secondary palm rotation shaft that meshes with the second spindle, and the second spindle that meshes with the second bevel gear.

[0016] The advantages and beneficial effects of this invention are as follows: 1. Through a three-stage coaxial nested structure, a large-stroke linear telescoping structure with a length several times that of the base is achieved within a limited radial envelope dimension. It has a large telescoping ratio and a compact radial dimension, which can easily extend into narrow spaces or pass through narrow channels. Combined with the rotational freedom around its own axis, it can flexibly adjust the end posture to complete the grasping, docking and operation of objects in different orientations.

[0017] 2. This electric telescopic rod mechanism has two independent degrees of freedom: linear extension and rotation. It has good motion decoupling, a simple control model, and can easily achieve independent or linked actions of extension and rotation through centralized control at the base end. The overall control is flexible and has a fast response.

[0018] 3. The mechanism is electrically driven, with all rotary and linear drive components centrally located on the base. The outward-extending sleeves and transmission components are purely mechanical structures, without electronic components such as motors, sensors, or circuit boards. This significantly reduces the risk of damage to the electronic system from harsh environments and helps improve the system's environmental adaptability and long-term operational reliability in special operating environments such as high temperature, dust, humidity, vibration, and confined spaces.

[0019] 4. The coaxial nested structure ensures high coaxiality of movement of each sleeve section during the extension and retraction process, making the extension and retraction process smooth and stable, and less prone to swaying or jamming. It facilitates high-precision linear displacement control and repeatable positioning through precise matching of lead screw and nut, as well as optional position detection elements such as magnetic grating and optical grating.

[0020] 5. This mechanism highly integrates long-stroke telescopic and continuous rotation functions into a single compact joint, eliminating the need for additional connecting parts and support structures required by the traditional linear and rotary modules connected in series. This reduces the number of parts and pipeline layout, resulting in lower overall costs and convenient installation and maintenance. It is particularly suitable as a highly integrated linear rotary transmission joint in various automated equipment under space-constrained conditions. Attached Figure Description

[0021] Figure 1 This is an isometric view of a two-degree-of-freedom coaxial nested three-stage electrically operated telescopic rotary joint structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of a two-degree-of-freedom coaxial nested three-stage electrically operated telescopic rotary joint; Figure 3 This is a schematic diagram of the rotating and transmission mechanism in this invention; Figure 4 yes Figure 2 Schematic diagram of section AA; Figure 5 Schematic diagram of the structure of the lower platform of the middle cylinder (A is the original view of the lower platform of the end cylinder; B is the schematic diagram after omitting the partition). Figure 6 yes Figure 5 Schematic diagram of the CC section; In the diagram: 1. Rotation and transmission mechanism; 2. First and second stage telescopic mechanism; 3. Second and third stage telescopic mechanism; 1-1. Rotation mechanism; 1-2. Transmission mechanism; 1-1-1. First protective cover; 1-1-2. Base main shaft; 1-1-3. Connecting plate; 1-1-4. Second protective cover; 1-1-5. Base cylinder platform; 1-1-6. Connecting seat; 1-1-7. Upper connecting rod; 1-1-8. Lower connecting rod; 1-1-9. Helical gear driven shaft; 1-1-10. Helical gear drive shaft; 1-2-1. Power input shaft; 1-2-2. 1. Helical gear; 1-2-3. Second helical gear; 1-2-4. First bevel gear; 1-2-5. Second bevel gear; 1-2-6. First driven shaft; 1-3-2. Wrist pitch first shaft; 1-3-3. Palm rotation first shaft; 1-2-7. Third bevel gear; 1-2-8. Intermediate transmission shaft; 1-2-9. Base platform; 1-2-10. Third helical gear; 1-2-11. Wrist rotation first shaft; 1-2-12. Fourth helical gear; 1-2-13. Fifth helical gear; 1-2-14. First spindle rod; 1 -2-15, Sixth helical gear; 1-2-16, First lead screw shaft; 1-2-17, Helical gear shaft; 1-2-18, Seventh helical gear; 2-1, Lower platform of middle cylinder; 2-2, Eighth helical gear; 2-3, Secondary transmission shaft; 2-3-1, Secondary shaft for wrist rotation; 2-3-2, Secondary shaft for wrist tilt; 2-3-3, Secondary shaft for palm rotation; 2-4, Ninth helical gear; 2-5, Second lead screw shaft; 2-6, First lead screw nut; 3-1, First gear; 3-2, Spur gear of spindle; 3-3, Second gear; 3-4 3-5. Third gear; 3-6. Second lead screw nut; 3-7. Third drive shaft; 3-8. Fourth gear; 3-9. Spur gear; 3-10. Lower platform of end cylinder; 4-1. U-shaped frame; 4-2-1. Wrist base gear; 4-2-2. Spur bevel gear; 4-2-3. Mandrel bevel gear; 4-3. Inner horizontal shaft of wrist; 4-4. L-shaped frame; 4-5-1. First bevel gear; 4-5-2. Second bevel gear; 4-5-3. Third bevel gear; 4-6. Palm rotating part; 4-7-1. Second mandrel; 4-7-2. Spur cylinder. Detailed Implementation

[0022] The specific embodiments of the present invention will be further described below with reference to examples. These examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0023] The present invention discloses a two-degree-of-freedom coaxial nested three-stage electric telescopic rotary joint structure, comprising a rotation and transmission mechanism 1, a first and second stage telescopic mechanism 2, and a second and third stage telescopic mechanism 3.

[0024] like Figure 1 , 2 As shown, the rotation and transmission mechanism 1 includes a linkage-driven rotation mechanism 1-1 and a multi-stage gear transmission mechanism 1-2.

[0025] The rotating mechanism 1-1 mainly includes a first protective cover 1-1-1, a base main shaft 1-1-2, a first connecting plate 1-1-3, a second protective cover 1-1-4, a base cylinder platform 1-1-5, a second connecting seat 1-1-6, an upper connecting rod 1-1-7, a lower connecting rod 1-1-8, a helical gear driven shaft 1-1-9, and a helical gear driving shaft 1-1-10.

[0026] The connection relationship between the various components is as follows: the helical gear driven shaft 1-1-9 is installed in the first protective cover 1-1-1 by bolts and can rotate relative to the first protective cover 1-1-1, and obtains torque by meshing with the helical gear drive shaft 1-1-10; two lower connecting rods 1-1-8 are fixed on both sides of the helical gear driven shaft 1-1-9, the upper end of the lower connecting rod 1-1-8 is hinged to the upper connecting rod 1-1-7 by studs, and is limited on the helical gear driven shaft 1-1-9; the upper end of the upper connecting rod 1-1-7 is connected to the second connecting seat 1-1-6 by studs; the lower end of the second protective cover 1-1-4 is provided with a base cylinder platform 1-1-5. The first protective cover 1-1-1 is connected to the first connecting plate 1-1-3 via the base main shaft 1-1-2; the first connecting plate 1-1-3 is connected to the second protective cover 1-1-4 via bolts; so that the lower end of the second protective cover 1-1-4 forms a structure that is hinged to the first protective cover 1-1-1 via the base main shaft 1-1-2. In actual use, the first protective cover 1-1-1 is the base of the whole equipment and is fixedly set on the foundation. The first and second stage telescopic mechanisms 2 and the second and third stage telescopic mechanisms 3 set on the upper part of the first protective cover 1-1-1 can be rotated and adjusted with the base main shaft 1-1-2 as the axis. The adjustment is controlled by folding or extending the lower connecting rod 1-1-8 and the upper connecting rod 1-1-7 in the rotating mechanism 1-1. The working principle is as follows: when the helical gear drive shaft 1-1-10 rotates, it drives the helical gear driven shaft 1-1-9 to rotate, and then drives the entire mechanism to rotate through the upper connecting rod 1-1-7 and the lower connecting rod 1-1-8, so that the upper telescopic mechanism can be rotated with controllable pitch angle around 1-1-2.

[0027] like Figure 2 , 3 As shown in Figure 4, the transmission mechanism 1-2 mainly includes a power input shaft 1-2-1, a first helical gear 1-2-2, a second helical gear 1-2-3, a first bevel gear 1-2-4, a second bevel gear 1-2-5, a first-stage driven shaft 1-2-6, a third bevel gear 1-2-7, an intermediate transmission shaft 1-2-8, a base platform 1-2-9, a third helical gear 1-2-10, a wrist rotation first-stage shaft 1-2-11, a fourth helical gear 1-2-12, a fifth helical gear 1-2-13, a first spindle rod 1-2-14, a sixth helical gear 1-2-15, a first lead screw shaft 1-2-16, a helical gear shaft 1-2-17, and a seventh helical gear 1-2-18.

[0028] The connection relationship between the various components is as follows: the first helical gear 1-2-2 and the second helical gear 1-2-3 are limited on the base platform 1-2-9. In this embodiment, two first helical gears 1-2-2 are arranged side by side in the base platform 1-2-9 to accommodate... Figure 2 , 3 For example, the lower end of the first helical gear 1-2-2 is connected to the power input shaft 1-2-1 located in the middle position in the figure. The two power input shafts 1-2-1 next to it pass directly through the base platform 1-2-9 and are arranged in a line with the two intermediate transmission shafts 1-2-8 on its upper part. In this embodiment, the two power input shafts 1-2-1 in the middle position are transferred to the two intermediate transmission shafts 1-2-8 through the first helical gear 1-2-2 and the second helical gear 1-2-3. The reason for this is to provide space for the setting of the helical gear drive shaft 1-1-10. Through the transmission of the first helical gear 1-2-2 and the second helical gear 1-2-3, the two power input shafts 1-2-1 in the middle position can bypass the helical gear drive shaft 1-1-10 and transmit power to the two intermediate transmission shafts 1-2-8.

[0029] The power input shaft 1-2-1 is connected to the first helical gear 1-2-2 via a key; the second helical gear 1-2-3 is connected to the intermediate transmission shaft 1-2-8 via a key and meshes with the first helical gear 1-2-2 to obtain torque; the first bevel gear 1-2-4 is connected to the power input shaft 1-2-1 and the intermediate transmission shaft 1-2-8 via a key, and four first bevel gears 1-2-4 are arranged in a straight line; there are four third bevel gears 1-2-7, and all four third bevel gears 1-2-7 are rotatably mounted on the base main shaft 1-1-2, and the four first bevel gears 1-2-4 are respectively connected to the four third bevel gears 1-2-8. -2-7 transmits power to the corresponding four second bevel gears 1-2-5. The two sides of the four third bevel gears 1-2-7 simultaneously mesh with the corresponding first bevel gears 1-2-4 and second bevel gears 1-2-5 to transmit torque. The second bevel gears 1-2-5 are connected to the first-stage driven shaft 1-2-6 by a key. The fourth helical gear 1-2-12 and the seventh helical gear 1-2-18 are connected to the two first-stage driven shafts 1-2-6 in the middle position by a key. It can be understood that the power of the fourth helical gear 1-2-12 and the seventh helical gear 1-2-18 is transmitted from the two intermediate transmission shafts 1-2-8.

[0030] The fifth helical gear 1-2-13 is connected to the lower end of the first spindle 1-2-14 via a key; the sixth helical gear 1-2-15 is connected to the lower end of the first lead screw 1-2-16 via a key; the third helical gear 1-2-10 meshes with the fourth helical gear 1-2-12 to obtain torque. The third helical gear 1-2-10 is installed at the lower end of the wrist rotation primary shaft 1-2-11. The fourth helical gear 1-2-12 meshes with the third helical gear 1-2-10 to drive it to rotate, thereby driving the wrist rotation primary shaft 1-2-11 to rotate; the helical gear shaft 1-2-17 meshes with the seventh helical gear 1-2-18. Two gear shafts 1-2-17 are provided and mesh with the two sides of the seventh helical gear 1-2-18 respectively. The two helical gear shafts 1-2-17 sequentially drive the sixth helical gear 1-2-15 and the fifth helical gear 1-2-13 respectively. The two fifth helical gears 1-2-13 drive the two first drive spindle rods 1-2-14 to rotate respectively. Similarly, the sixth helical gear 1-2-15 drives the two first lead screw shafts 1-2-16 to rotate respectively. The sixth helical gear 1-2-15 meshes with the helical gear shaft 1-2-17; the fifth helical gear 1-2-13 meshes with the sixth helical gear 1-2-15.

[0031] The working principle is as follows: When the two middle power input shafts 1-2-1 rotate, the first helical gear 1-2-2 meshes with the second helical gear 1-2-3, transmitting torque to rotate the middle transmission shaft 1-2-8; the first bevel gear 1-2-4, driven by the middle transmission shaft 1-2-8 and the other two power input shafts 1-2-1, sequentially transmits power to the third bevel gear 1-2-7 and the second bevel gear 1-2-5, causing the first-stage driven shaft 1-2-6 to rotate; among them, one of the first-stage driven shafts 1-2-6, through the third helical gear 1-2-10 and the fourth helical gear 1-2-12, causes the wrist to rotate. The rotation of the first-stage shaft 1-2-11, and the wrist rotation of the first-stage shaft 1-2-11, are used to transmit power to the upper end; there is also a first-stage driven shaft 1-2-6 whose upper end is connected to the seventh helical gear 1-2-18. The seventh helical gear 1-2-18 is used to drive the two helical gear shafts 1-2-17, the two sixth helical gears 1-2-15 and the two fifth helical gears 1-2-13 to rotate synchronously, so that the first spindle rod 1-2-14 and the first lead screw shaft 1-2-16 rotate. The rotation of the first spindle rod 1-2-14 and the first lead screw shaft 1-2-16 is used to transmit power to the upper end and control the synchronous extension and retraction of the three-stage telescopic mechanism.

[0032] like Figure 1 As shown, the three-stage telescopic mechanism includes a base tube, a middle tube, and an end tube that are sequentially nested from bottom to top. The bottom of the base tube is hinged to the protective cover 1-1-1. The base tube and the middle tube constitute the first and second stage telescopic mechanism 2, and the middle tube and the end tube constitute the second and third stage telescopic mechanism 3. Figure 2 As shown, the first and second level telescopic mechanism 2 includes a lower platform 2-1 of the middle cylinder, an eighth helical gear 2-2, a second level transmission shaft 2-3, a ninth helical gear 2-4, a second lead screw shaft 2-5, and a first lead screw nut 2-6.

[0033] The connection relationship between the various components is as follows: the lower platform 2-1 of the middle cylinder is fixedly set at the bottom of the middle cylinder. The lower platform 2-1 of the middle cylinder is connected to and limits all rods through bearings; the first lead screw nut 2-6 is fixedly installed on the lower platform 2-1 of the middle cylinder. The first lead screw nut 2-6 is threaded to the first lead screw shaft 1-2-16. The drive line of the first lead screw shaft 1-2-16 is: the seventh helical gear 1-2-18 → the two helical gear shafts 1-2-17 on both sides → the two sixth helical gears 1-2-15 → the first lead screw shaft 1-2-16.

[0034] The drive path of the second lead screw shaft 2-5 is as follows: seventh helical gear 1-2-18 → two helical gear shafts 1-2-17 on both sides → two sixth helical gears 1-2-15 → two fifth helical gears 1-2-13 → two first spindle rods 1-2-14 → two second lead screw shafts 2-5.

[0035] Three eighth helical gears 2-2 are keyed to the bottom of three secondary transmission shafts 2-3. When the three eighth helical gears 2-2 rotate, the torque is transmitted upwards through the three secondary transmission shafts 2-3, such as... Figure 6 As shown, the secondary transmission shaft 2-3 is specifically divided into three shafts: wrist rotation secondary shaft 2-3-1, wrist pitch secondary shaft 2-3-2, and palm rotation secondary shaft 2-3-3. Three ninth helical gears 2-4 are connected to the primary driven shaft 1-2-6 and the wrist rotation primary shaft 1-2-11 respectively via keys. The second lead screw shaft 2-5 and the first spindle rod 1-2-14 form a sleeve structure. The first spindle rod 1-2-14 is a spindle that slides inside the second lead screw shaft 2-5, and the second lead screw shaft 2-5 and the first spindle rod 1-2-14 are configured to rotate synchronously. When the middle cylinder extends or retracts relative to the base cylinder, the second lead screw shaft 2-5 slides relative to the first spindle rod 1-2-14, and their synchronous rotation transmits torque upwards through the second lead screw shaft 2-5. Three sets of eighth helical gears 2-2 mesh with the ninth helical gears 2-4.

[0036] The working principle is as follows: When the two first lead screw shafts 1-2-16 rotate, they are synchronously driven by the seventh helical gear 1-2-18. Through the first lead screw nut 2-6 threadedly connected to it, the lower platform 2-1 of the middle cylinder and the first-stage sleeve connected to it extend or retract axially. The upper part of the two first-stage driven shafts 1-2-6 and the wrist rotation first-stage shaft 1-2-11 are respectively connected to a ninth helical gear 2-4. Through the meshing of the ninth helical gear 2-4 with the eighth helical gear 2-2, the three second-stage transmission shafts 2-3 rotate independently, which are used to drive the three degrees of freedom adjustment of the "mechanical hand" at the top of the top cylinder. The first lead screw shaft 1-2-16 rotates synchronously with the second lead screw shaft 2-5 and the first mandrel 1-2-14.

[0037] like Figure 5 , 6 As shown, the second and third stage telescopic mechanism 3 includes a first gear 3-1, a spindle spur gear 3-2, a second gear 3-3, a third gear 3-4, a second lead screw nut 3-5, a third transmission shaft 3-6, a fourth gear 3-8, a sleeve shaft spur gear 3-9, and an end cylinder lower platform 3-10.

[0038] The connection relationship between the various components is as follows: the lower platform 3-10 of the end cylinder is a platform that can be axially slidably controlled and set inside the middle cylinder. The bottom end of the end cylinder passes into the middle cylinder and is fixedly connected to the lower platform 3-10 of the end cylinder. The lower platform 3-10 of the end cylinder is connected and limits all rods through bearings. The second lead screw nut 3-5 is threaded to cooperate with two second lead screw shafts 2-5. It can be understood that the two second lead screw shafts 2-5 rotate synchronously. According to the principle of linear motor, the end cylinder can be pushed to extend and retract to move through the second lead screw nut 3-5, and then the end cylinder can be lifted through the second lead screw nut 3-5.

[0039] The first gear 3-1, the third gear 3-4, and the fourth gear 3-8 are connected to three secondary transmission shafts 2-3 respectively via keys (specifically: wrist rotation secondary shaft 2-3-1, wrist tilt secondary shaft 2-3-2, and palm rotation secondary shaft 2-3-3); the second gear 3-3 is connected to the third transmission shaft 3-6 via a key; the first gear 3-1 meshes with the spindle spur gear 3-2; the second gear 3-3 meshes with the third gear 3-4; and the sleeve spur gear 3-9 meshes with the fourth gear 3-8. The spindle spur gear 3-2 and the sleeve spur gear 3-9 are sleeve shaft designs, meaning the spindle spur gear 3-2 is the spindle inside the sleeve spur gear 3-9, and the two rotate independently.

[0040] The working principle is as follows: When the two second lead screw shafts 2-5 rotate, they drive the lower platform 3-10 of the end cylinder and the end cylinder connected to it to extend or retract axially through the second lead screw nut 3-5 and the second lead screw nut 3-5; the wrist rotation secondary shaft 2-3-1 causes the third transmission shaft 3-6 to rotate through the second gear 3-3 and the third gear 3-4; the wrist pitch secondary shaft 2-3-2 causes the sleeve shaft spur gear 3-9 to rotate through the fourth gear 3-8; the palm rotation secondary shaft 2-3-3 causes the core shaft spur gear 3-2 to rotate through the first gear 3-1.

[0041] like Figure 2 As shown, the upper end of the third drive shaft 3-6 meshes with the wrist base gear 4-2-1, thereby driving the U-shaped frame to rotate circumferentially; the rotation of the sleeve shaft spur gear 3-9 drives the sleeve shaft cylinder 4-7-2 to rotate, which in turn drives the L-shaped frame to rotate through the first bevel gear 4-5-1 at its top, thereby controlling the pitch posture adjustment of the palm rotation part 4-6; the rotation of the spindle spur gear 3-2 drives the second spindle 4-7-1 to rotate, which in turn drives the third bevel gear 4-5-3 → the second bevel gear 4-5-2 in sequence, thereby controlling the rotation adjustment of the palm rotation part 4-6.

[0042] The working process of this invention in a real-world operating scenario is as follows: refer to Figure 1-6When the working environment requires the mechanism to rotate around its own axis to adjust the posture of the end effector or gripper, the rotary drive device integrated in the base drives the helical gear drive shaft 1-1-10 to rotate, which in turn drives the helical gear driven shaft 1-1-9 to rotate via gear meshing. The helical gear driven shaft drives the lower connecting rod 1-1-8 to swing via a key or bolt connection. The lower connecting rod and the upper connecting rod 1-1-7 are connected by studs to form a rotating pair. The other end of the upper connecting rod is connected to the second connecting seat 1-1-6, while the connecting block is fixed to the second protective cover 1-1-4 and the base cylinder platform 1-1-5. These components and the entire telescopic sleeve assembly are supported in the base by bearings. When the helical gear driven shaft rotates, the linkage mechanism drives the entire sleeve assembly to rotate around its own central axis, allowing the end effector to adjust its posture at any angle to align with objects in different directions. This rotational motion and telescopic motion use independent drive sources, which can operate independently or in conjunction to achieve coordinated control of the end effector position and posture.

[0043] When it is necessary to extend the end in a confined space to grasp or manipulate a distant target, the telescopic drive motor starts, driving the power input shaft 1-2-1 in the transmission mechanism 1-2 to rotate. The first helical gear 1-2-2 on the drive shaft transmits power to the second helical gear 1-2-3, which then distributes the motion to multiple first-stage driven shafts 1-2-6 via the intermediate transmission shaft 1-2-8 and bevel gear sets 1-2-4, 1-2-5, and 1-2-7. Among them, some of the first-stage driven shafts drive two first spindle rods 1-2-14 to rotate in the same direction and at the same speed through the fourth helical gear 1-2-12 and the fifth helical gear 1-2-13. The first lead screw shaft 1-2-16 cooperates with the first lead screw nut 2-6 fixed on the lower platform 2-1 of the middle cylinder, pushing the fixed platform 1 and the first-stage sleeve connected to it to extend linearly relative to the base. Simultaneously, the ninth helical gear 2-4 on the primary driven shaft and the wrist-rotating primary shaft 1-2-11 meshes with the eighth helical gear 2-2 on the secondary transmission shaft 2-3, driving the three secondary transmission shafts to rotate. This, in turn, transmits power to the second lead screw shaft 2-5 via the first lead screw shaft 1-2-16. The lead screw shaft 2 engages with the second lead screw nut 3-5 fixed on the lower platform 3-10 of the end sleeve, pushing the secondary sleeve to extend synchronously relative to the primary sleeve. Because the gear transmission chain ensures that the rotational speed ratio and lead of each lead screw are matched, the secondary sleeve can extend smoothly with the primary sleeve at the designed speed ratio, achieving complete synchronous unfolding of the three sleeves, ultimately obtaining a total extension several times the base length. The entire extension process exhibits high coaxiality, and the end displacement is precisely controllable. When retraction is required, the drive motor reverses, the transmission chain moves in the opposite direction, and the sleeve retracts step by step, returning to its initial compact state.

[0044] In practical applications, the base of this electric telescopic rod mechanism can be installed on the outside of isolation walls, equipment walls, or hatches. It extends into the interior through narrow operating holes, and the direction of the end effector can be adjusted using rotational degrees of freedom to perform operations such as equipment maintenance, sampling, and foreign object retrieval. Since all driving components are located at the base end, and the sleeve and transmission components extending into complex areas are purely mechanical structures without electronic components, the long-term reliability of the system is fundamentally improved.

[0045] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A two-degree-of-freedom coaxial nested three-stage electrically operated telescopic rotary joint structure, characterized in that, include: The system comprises a base end, a sleeve assembly, and a robotic arm. The bottom of the base cylinder of the sleeve assembly is hinged to the base end to form the first degree of freedom of the telescopic rotary joint structure. The sleeve assembly is adjusted along its axial direction to form the second degree of freedom of the telescopic rotary joint structure. The sleeve assembly includes a base cylinder, a middle cylinder, and an end cylinder that are sequentially nested together, and the middle cylinder and the end cylinder are synchronously linked for telescopic control. A robotic arm is provided at the upper end of the end cylinder. The rotating and transmission mechanism is located within the telescopic rotating joint structure and includes a rotating mechanism and a transmission mechanism; the first and second stage telescopic mechanisms are located between the base cylinder and the middle cylinder; the second and third stage telescopic mechanisms are located between the middle cylinder and the end cylinder. The telescopic rotary joint structure is equipped with multiple independent mechanical transmission chains, including a pitch transmission chain that controls the bending adjustment of the sleeve assembly relative to the base end, and a telescopic transmission chain that controls the linear extension and retraction of the sleeve assembly.

2. The two-degree-of-freedom coaxial nested three-stage electrically operated telescopic rotary joint structure according to claim 1, characterized in that, The robotic hand comprises three degrees of freedom: a wrist rotation section, a wrist pitch section, and a palm rotation section. The wrist rotation section is rotatably mounted on the top of the end cylinder. The wrist pitch section is rotatably mounted on the wrist rotation section and allows for controlled pitch angle adjustment relative to it. The palm rotation section is rotatably mounted on the wrist pitch section. The mechanical transmission chain also includes a wrist rotation transmission chain, a wrist pitch transmission chain, and a palm rotation transmission chain.

3. The two-degree-of-freedom coaxial nested three-stage electrically operated telescopic rotary joint structure according to claim 2, characterized in that, The base end and the base cylinder are hinged together by a base main shaft. The base end has a base platform inside, and the base cylinder has a base cylinder platform inside. The pitch transmission chain includes a helical gear drive shaft, a helical gear driven shaft, a lower connecting rod, and an upper connecting rod. The helical gear drive shaft is rotatably arranged along the inner axis of the base end. A helical gear driven shaft is meshed on one side of the helical gear drive shaft, and the two shafts are arranged perpendicular to each other. The lower end of the lower connecting rod is fixedly connected to the helical gear driven shaft, and the upper end is hinged to the upper connecting rod. The upper end of the upper connecting rod is hinged to the outer wall of the base cylinder. The pitch transmission chain also includes a power input shaft and a first bevel gear mounted on the base platform. The power input shaft has four shafts and drives the four first bevel gears to rotate accordingly. The base platform has four primary driven shafts that rotate, and each primary driven shaft has a second bevel gear at its lower end. The base main shaft is rotatably equipped with four third bevel gears, and each third bevel gear is meshed with a first bevel gear and a second bevel gear on both sides to form four sets of three-axis bevel gear pairs. The lower end of the middle cylinder is slidably inserted into the base cylinder, and the lower end of the middle cylinder is fixedly provided with a lower platform. The lower end of the end cylinder is slidably inserted into the middle cylinder, and the lower end of the end cylinder is fixedly provided with a lower platform.

4. The two-degree-of-freedom coaxial nested three-stage electrically operated telescopic rotary joint structure according to claim 3, characterized in that, The telescopic transmission chain includes a first mandrel, a first lead screw shaft, and a second lead screw shaft. The first mandrel and the first lead screw shaft are rotatably disposed inside the base cylinder, and the second lead screw shaft is rotatably disposed inside the middle cylinder. A first lead screw nut is provided on the lower platform of the middle cylinder, and the first lead screw shaft is threadedly connected to the first lead screw nut. The first mandrel is a mandrel that slides inside the second lead screw shaft, and the two are connected by a sliding spline. A second lead screw nut is fixedly disposed on the lower platform of the end cylinder, and the second lead screw shaft is threadedly connected to the second lead screw nut.

5. The two-degree-of-freedom coaxial nested three-stage electrically operated telescopic rotary joint structure according to claim 4, characterized in that, The output end of one of the three-axis bevel gear pairs is provided with a seventh helical gear on the base cylinder platform. The seventh helical gear drives two symmetrical first spindle rods and two first lead screw shafts through gear meshing transmission. Two helical gear shafts are meshed and connected to both sides of the seventh helical gear. The two helical gear shafts are meshed and connected to a sixth helical gear respectively. The rear stage of the sixth helical gear is meshed and connected to a fifth helical gear. The sixth helical gear drives the first lead screw shaft to rotate, and the fifth helical gear drives the first spindle rod to rotate.

6. The two-degree-of-freedom coaxial nested three-stage electrically operated telescopic rotary joint structure according to claim 3, characterized in that, The wrist rotation part includes a U-shaped frame rotatably mounted on the upper end of the end tube. The lower end of the U-shaped frame extends into the end tube and is provided with a wrist base gear along the axial direction. The wrist tilting part and the palm rotation part are disposed in the U-shaped opening of the U-shaped frame. The wrist tilting part includes an inner wrist axis, an L-shaped frame, and a first bevel gear. The inner wrist axis is transversely disposed between the two side walls of the U-shaped frame. The first bevel gear is fixedly disposed on one side of the L-shaped frame and both are rotatably mounted on the inner wrist axis. A second bevel gear is rotatably disposed on the other side of the L-shaped frame. The palm rotation part is disposed on the second bevel gear. A third bevel gear is rotatably mounted on the inner wrist axis. The third bevel gear meshes with the second bevel gear. A spindle bevel gear and a sleeve bevel gear are provided inside the U-shaped frame and coaxially with the wrist base gear. The sleeve bevel gear meshes with the first bevel gear, and the spindle bevel gear meshes with the third bevel gear. The end cylinder is rotatably equipped with a third drive shaft, a second spindle, and a sleeve cylinder. The second spindle is rotatably mounted inside the sleeve cylinder. A sleeve bevel gear is connected to the upper end of the sleeve cylinder, and a sleeve spur gear is connected to the lower end. A spindle bevel gear is connected to the upper end of the second spindle, and a spindle spur gear is connected to the lower end. The upper end of the third drive shaft meshes with a wrist base gear, and the lower end is equipped with a second gear. The second gear, the spindle spur gear, and the sleeve spur gear are all rotatably mounted within the lower platform of the end cylinder.

7. The two-degree-of-freedom coaxial nested three-stage electrically operated telescopic rotary joint structure according to claim 6, characterized in that, A fourth helical gear is provided at the output end of one of the three-axis bevel gear pairs on the base cylinder platform; The wrist rotation transmission chain is driven by the fourth helical gear through gear meshing to the first-stage wrist rotation shaft. The first-stage wrist rotation shaft is driven by the shaft end meshing to the second-stage wrist rotation shaft. The second-stage wrist rotation shaft is driven by the shaft end meshing to the third transmission shaft. The third transmission shaft drives the wrist base gear.

8. The two-degree-of-freedom coaxial nested three-stage electrically operated telescopic rotary joint structure according to claim 6, characterized in that, The output end of one of the three-axis bevel gear pairs is connected to the wrist pitch primary shaft; The wrist pitch transmission chain consists of a primary wrist pitch shaft that meshes with a secondary wrist pitch shaft at its shaft end, which in turn meshes with a sleeve at its shaft end. The sleeve meshes with a first bevel gear.

9. A two-degree-of-freedom coaxial nested three-stage electrically operated telescopic rotary joint structure according to claim 6, characterized in that, The output end of one of the three-axis bevel gear pairs is connected to the first-stage shaft for rotating the palm; The palm rotation transmission chain consists of a primary palm rotation shaft that meshes with the secondary palm rotation shaft at its shaft end, the secondary palm rotation shaft that meshes with the second spindle at its shaft end, and the second spindle that meshes with the second bevel gear.

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