Hydraulically driven large angle robot joint

Abstract

The application relates to a hydraulic drive large-angle robot joint, and relates to the field of robot joints. The application solves the problems of high complexity, high redundancy, large volume and heavy weight of the existing hydraulic robot joint. The application comprises a shell unit, a torque transmission system and a swing cylinder driving system, the torque transmission system and the swing cylinder driving system are connected and embedded in the shell unit, the swing cylinder driving system provides reciprocating linear swing driving power and is slidably connected with an input end of the torque transmission system, linear motion of the swing driving power is converted into torque power source of rotation of the torque transmission system, and the torque transmission system outputs torque. The application directly outputs the required torque by the swing cylinder to drive the joint, simplifies the transmission structure, and utilizes the advantages of hydraulic drive in the power mass ratio. The overall motion performance of the robot is improved, the volume and weight of the robot are reduced, and high efficient driving capacity is ensured. The application is used in humanoid robots.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of robots, in particular to a hydraulic drive large-angle robot joint for humanoid robots in large load and large-angle environments. BACKGROUND

[0002] Compared with traditional wheeled and tracked robots, humanoid robots exhibit unique advantages, including stronger terrain adaptability, lower energy consumption, wider range of activities, and the ability to mimic human walking. They can move freely without the need to modify the human living environment. The humanoid form of humanoid robots also makes them more easily accepted by humans. However, due to technical limitations, humanoid robots have not yet fully reached the level of human movement and perception, so no products have been able to fully integrate into daily life.

[0003] Improving the joint configuration of humanoid robots is crucial to improving their movement performance. The hip of the robot concentrates multiple degrees of freedom, and innovative design of the hip joint structure directly affects the ground adaptability, energy consumption, workspace, and biped walking ability of the robot.

[0004] In recent years, researchers around the world have been constantly innovating in the design of robot leg joint structures. In 2015, a team from the Italian Institute of Technology developed a new type of bionic hydraulic drive joint, which is simple in design and has high carrying capacity. The joint uses a linear hydraulic cylinder and a linkage hinge structure to mimic the movement characteristics of the human knee joint, with a changing instantaneous center of rotation.

[0005] In 2016, researchers at the Korea Institute of Industrial Technology designed a high-performance hydraulic lasso drive joint suitable for distal drive robots. This device consists of two linear hydraulic cylinders, a transmission lasso, and a joint turntable, among other components. It not only provides a large torque output but also has excellent bandwidth and fast response characteristics.

[0006] In 2024, the team of Bai Xiangjuan from the University of Defense Science and Technology based on the bionic research of human joints proposed a high-efficiency bionic hydraulic actuator, which integrates two pumps, two cylinders, three valves, and two motors in a compact structure. Reducing hydraulic throttling losses greatly improves the efficiency of wearable robot systems.

[0007] However, existing hydraulic robot joints mostly use linear hydraulic cylinders and transmission mechanisms to achieve this. This design has the problem of high complexity and redundancy in mechanical structure, and is not superior in terms of volume and weight.

[0008] In summary, existing hydraulic robot joints have the problems of high complexity and redundancy, and large volume and weight. SUMMARY

[0009] The present application aims at solving the problems of high complexity, redundancy, volume and weight of the existing hydraulic robot joints, and providing a hydraulic driving large-angle robot joint.

[0010] The technical scheme of the present application is:

[0011] The hydraulic driving large-angle robot joint comprises a shell unit, a torque transmission system and a swing cylinder driving system, wherein the torque transmission system and the swing cylinder driving system are connected and embedded in the shell unit, the swing cylinder driving system provides reciprocating linear swing driving power and is slidably connected with the input end of the torque transmission system, the linear motion of the swing driving power is converted into the torque power source of the rotation of the torque transmission system, and the torque is output by the torque transmission system.

[0012] Further, the shell unit comprises a swing cylinder bottom cover, a swing cylinder shell and a swing cylinder top cover, and the swing cylinder bottom cover and the swing cylinder top cover are respectively covered on both sides of the length direction of the swing cylinder shell.

[0013] Further, the swing cylinder driving system comprises a hydraulic cylinder body and a sliding block, the hydraulic cylinder body is embedded in the swing cylinder shell, two hydraulic oil input ports are arranged on the hydraulic cylinder body and the hydraulic cylinder body linearly swings in the swing cylinder shell, one end of the sliding block is installed on the outer side wall of the middle part of the hydraulic cylinder body, and the other end of the sliding block is slidably connected with the torque transmission system.

[0014] Preferably, the swing cylinder driving system further comprises two symmetrical sliding guide assemblies arranged on both sides of the hydraulic cylinder body, each sliding guide assembly comprises an oil feeding shaft, a sealing ring and a hydraulic cylinder end cover, the oil feeding shaft is sealingly installed on one side of the hydraulic cylinder body through the sealing ring, and the hydraulic cylinder end cover is covered on the side surface of the hydraulic cylinder body.

[0015] Preferably, the swing cylinder driving system further comprises a hydraulic servo valve and two oil pressure sensors, the hydraulic servo valve and the two oil pressure sensors are installed in the swing cylinder shell and connected with the hydraulic cylinder body.

[0016] Further, the torque transmission system comprises a planetary gear carrier, a fixed ring and a planetary gear train, a groove is arranged on the connecting surface of the swing cylinder driving system, the groove is arranged in the radial direction of the planetary gear carrier, the other end of the sliding block is inserted into the groove, and the height of the side wall of the groove is higher than the height of the frame body of the planetary gear carrier; the planetary gear carrier is installed on the planetary gear train through the fixed ring.

[0017] Further, the planetary gear train comprises an outer gear ring, gear bearings, an output gear shaft, planetary gear shafts, gear shaft clamps and a plurality of planetary gears, the output gear shaft is coaxially rotatably installed in the outer gear ring, the plurality of planetary gears are installed in the outer gear ring and meshed with the output gear shaft and the inner teeth of the outer gear ring, a planetary gear shaft is inserted on each planetary gear, and a gear bearing is sleeved between the planetary gear and the planetary gear shaft, and the planetary gear shaft is provided with a gear shaft clamp at one end.

[0018] Preferably, the planetary gear is a spoke gear.

[0019] Further, the torque transmission system further comprises a planetary carrier clamp and a planetary carrier bearing, the planetary carrier clamp and the planetary carrier bearing are sleeved on the planetary carrier and embedded in the inner hole of the fixed ring.

[0020] Further, the torque transmission system further comprises a magnetic encoder and an upper end bearing, the magnetic encoder and the upper end bearing are sleeved on the output gear shaft and embedded in the middle part of the swing cylinder top cover.

[0021] Compared with the prior art, the present application has the following effects:

[0022] The present application specifically provides a hydraulic drive large-angle robot joint applied to a hydraulic humanoid robot hip, adopts a layer-by-layer embedding mode, so that the robot joint structure is more compact, under a smaller external size, the torque transmission system can output a larger torque under the driving of the swing cylinder driving system, and realizes a 0-360° large-angle rotation at the output gear shaft 4; the internal structure of the swing cylinder driving system is precise, can realize accurate control and good sealing, and overcomes the complexity in control, the redundancy that may occur in the transmission system structure, and the limitations in volume and weight of the traditional linear hydraulic cylinder and other shortcomings. Although the linear cylinder structure is simple and convenient to control, a connecting rod and other transmission mechanisms are needed to realize the rotation movement of the robot joint, and a large structure space is occupied, which is difficult to arrange in a limited space such as a humanoid robot hip joint and shoulder joint. The traditional hydraulic swing cylinder has the disadvantages of large weight, high processing requirement, difficult compatibility of friction and leakage, and small rotation range (cannot reach 360 degrees). The present application adopts a short-range linear cylinder plus a planetary speed increasing mechanism (planetary gear train) to realize the design of a robot joint with large rotation angle, large load and small volume, and has the characteristics of simple structure, easy installation and control of the linear hydraulic cylinder, and the advantages of compact structure and good sealing effect of the swing type hydraulic cylinder, and is a swing type robot joint capable of realizing large rotation angle.

[0023] The above technical effects are achieved by the following way:

[0024] 1. Large rotation angle can be achieved: the previous transmission mode of linear hydraulic cylinder combined with connecting rod, due to the limitation of geometric relationship, the joint limit range can only reach half a circle at most, while the output shaft rotation angle of the large angle robot joint of the application can reach one circle, greatly improving the movable range of the joint of the robot and the motion ability of the robot.

[0025] 2. The load capacity is improved: the large diameter hydraulic cylinder is adopted, the joint can provide very strong output torque, which can be used not only for the pitch freedom degree of the connection between the thigh and the pelvic bone, but also for the rotation freedom degree of the waist, the leg yaw freedom degree and other large load joint freedom degrees.

[0026] 3. Hollow structure design of the joint: the hollow structure (located at the center of the output gear shaft) of the robot joint is designed as a highlight, which facilitates the arrangement of oil pipes and lines, makes the overall arrangement of the robot more compact, and is more convenient to install and disassemble.

[0027] 4. The transmission structure is more compact: the hydraulic oil directly enters the piston rod (the piston rod is located at the left and right ends of the hydraulic cylinder body) from the pipeline in the shell unit through the oil delivery shaft 17 and the rotary oil return joint, and then enters the cylinder body, without the need for additional oil circuit for oil delivery, reducing the manufacturing difficulty and cost. The hydraulic cylinder shell adopts 3D printing processing technology, the overall structure is simple to process, and the installation and disassembly are convenient, so that the whole transmission structure is more compact.

[0028] 5. High-speed response and high-precision control of the joint can be achieved: servo valve, oil pressure sensor and MBS magnetic encoder are adopted to realize servo closed loop control, which can realize real-time sensing of joint state and control of oil pressure and flow, realize precise control, control is convenient, and position accuracy is guaranteed. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is an exploded view of the application; Figure 2 is a schematic view of the overall structure after assembly of the application; Figure 3 is a longitudinal section view of the application; Figure 4 is a mechanism diagram of the application.

[0030] BRIEF DESCRIPTION OF DRAWINGS:

[0031] 1, swing cylinder top cover, 2, magnetic encoder, 3, upper end bearing, 4, output gear shaft, 5, planetary gear, 6, outer gear ring, 7, planetary gear shaft, 8, gear bearing, 9, gear shaft clamp spring, 10, fixed ring, 11, planetary gear carrier clamp spring, 12, planetary gear carrier bearing, 13, planetary gear carrier, 14, swing cylinder shell, 15, hydraulic servo valve, 16, oil pressure sensor, 17, oil delivery shaft, 18, sealing ring, 19, hydraulic cylinder end cover, 20, sliding block, 21, hydraulic cylinder body, 22, swing cylinder bottom cover. DETAILED DESCRIPTION

[0032] Detailed implementation one: combination Figures 1 to 4 In this embodiment, the housing unit further comprises a torque transmission system and a swing cylinder driving system, which are connected and embedded in the housing unit, wherein the swing cylinder driving system provides reciprocating linear swing driving power and is slidably connected with the input end of the torque transmission system, converts the linear motion of the swing driving power into the torque power source of the rotation of the torque transmission system, and outputs the torque by the torque transmission system.

[0033] The present application adopts a new type of swing hydraulic cylinder as the driving unit of the robot joint. This design of swing cylinder driving system drives the torque transmission system to directly output the required torque to drive the joint, simplifying the transmission structure, and at the same time taking advantage of the power-to-mass ratio of hydraulic drive. Such improvements are expected to improve the overall motion performance of the robot, while reducing its volume and weight, while ensuring high driving capacity.

[0034] Detailed implementation two: combination Figures 1 to 3 In this embodiment, the housing unit comprises a swing cylinder bottom cover 22, a swing cylinder shell 14 and a swing cylinder top cover 1, and the swing cylinder bottom cover 22 and the swing cylinder top cover 1 are respectively covered on both sides of the length direction of the swing cylinder shell 14. In this way, the upper part of the dry pipe fitting plate 22 is provided with a protrusion for cooperation, realizing the sliding connection between the spoiler 2 and the dry pipe fitting track 1, which is mainly used for determining the specific position of the spoiler 2 before the spoiler 2 is fixed on the dry pipe fitting track 1. During the selection of the used position, after the specific position is determined, the dry pipe fitting plate 22 and the dry pipe fitting track 1 are fixed by the sealing layer. The other components are the same as in the first embodiment.

[0035] The housing unit and the output gear 4 of this embodiment are all made by using 3D printing technology, and titanium alloy high-performance metal is selected. After printing, shot blasting process is used on the housing to improve the surface performance, and then finishing is carried out to complete the machining of various planes and holes, thereby reducing the occupied space and weight to the greatest extent.

[0036] In the process of designing the housing unit in this embodiment, how to install the piston rod and ensure smooth oil passage is fully considered, and a scheme is proposed as follows: C-shaped grooves are opened on both sides of the shell wall of the swing cylinder shell 14, the piston rod is installed from the top, and after installation, a fixing block is arranged on the bottom cover, so that the radial position of the piston rod can be ensured after the bottom cover is installed.

[0037] In addition, the shell unit of the robot joint is subjected to finite element analysis, thereby effectively improving the shell rigidity and stability, and playing a role of constraint feedback in the whole swing joint optimization design link. Through continuous iteration under the constraint conditions of stress and design space, the structure of the swing joint shell model is determined.

[0038] Specific implementation three: combined Figure 1 and Figure 4 The swing cylinder driving system of the embodiment includes a hydraulic cylinder body 21 and a sliding block 20. The hydraulic cylinder body 21 is embedded in a swing cylinder shell 14, and two hydraulic oil input ports are arranged on the hydraulic cylinder body 21 and linearly swing in the swing cylinder shell 14. One end of the sliding block 20 is mounted on the outer side wall of the middle part of the hydraulic cylinder body 21, and the other end of the sliding block 20 is slidingly connected with a torque transmission system.

[0039] In this way, the shell and oil circuit of the hydraulic cylinder body 21 are designed integrally. The annular control circuit board is installed in the shell interior through the rotation of the hydraulic cylinder driving planetary gear train. The other components and connection relationship are the same as those in the first or second embodiment.

[0040] The hydraulic driving large-angle robot joint of the embodiment provides an implementation mode in the realization of reciprocating linear motion. The swing cylinder (hydraulic cylinder body 21) is a cylinder barrel, the position of which is fixed through a hollow piston rod. The piston rod is fixed on the shell of the swing cylinder. The middle baffle structure divides the cylinder barrel into two cavities. The two cavities are supplied with oil through two rotary oil joints at the two ends of the piston rod. The guide rod in the middle of the cylinder barrel is connected with a sliding block. The sliding block transmits kinetic energy through the sliding groove on the flange of the planetary gear output (i.e., the planetary gear carrier 13), converts the pushing force of the cylinder barrel into the torque of the flange, and fixes the outer ring gear of the planetary gear train on the shell. The torque is transmitted outward through the sun gear shaft.

[0041] During work, the hydraulic oil enters the piston rod through the pipeline under the control of the servo valve, and then enters the two liquid cavities of the cylinder barrel through the openings on the piston rod wall, thereby pushing the cylinder barrel to move. The hydraulic cylinder displacement and pressure information sensing are realized through the oil pressure sensor on the oil circuit. The cylinder barrel is connected with a sliding block connector on one side. The sliding block in the sliding groove pushes the planetary gear output flange to rotate. The planetary gear output flange is connected with the planetary gear through a small bearing. When the planetary gear output flange rotates around the shaft center, the outer ring gear is fixed. The planetary gear transmits the movement to the sun gear shaft, and the shaft drives the subsequent joint and the thigh to rotate in the pitch direction.

[0042] Specific implementation four: combined Figure 1The embodiment is described, the swing cylinder driving system of the embodiment further comprises two symmetrical sliding guide assemblies arranged on both sides of the hydraulic cylinder body 21, each sliding guide assembly comprises an oil supply shaft 17, a sealing ring 18 and a hydraulic cylinder end cover 19, the oil supply shaft 17 is sealingly installed on one side of the hydraulic cylinder body 21 through the sealing ring 18, and the hydraulic cylinder end cover 19 is coveringly installed on the side of the hydraulic cylinder body 21.

[0043] In this way, the sliding guide assembly of the embodiment can correspond to a piston rod, and can drive the hydraulic cylinder body 21 to perform linear reciprocating motion after the hydraulic oil is introduced into the hydraulic cylinder body 21. The other components and connection relationships are the same as any one of the first to third embodiments.

[0044] The seventh embodiment is described in combination with the first to sixth embodiments. Figure 1 The embodiment is described, the swing cylinder driving system of the embodiment further comprises two symmetrical sliding guide assemblies arranged on both sides of the hydraulic cylinder body 21, each sliding guide assembly comprises an oil supply shaft 17, a sealing ring 18 and a hydraulic cylinder end cover 19, the oil supply shaft 17 is sealingly installed on one side of the hydraulic cylinder body 21 through the sealing ring 18, and the hydraulic cylinder end cover 19 is coveringly installed on the side of the hydraulic cylinder body 21.

[0045] In this way, the hydraulic servo valve 15 is driven by the hydraulic controller to control the flow, speed and direction of the hydraulic oil flowing into the hydraulic cylinder. The oil pressure sensor 16 can realize control feedback and increase the control accuracy. The other components and connection relationships are the same as any one of the first to fourth embodiments.

[0046] The seventh embodiment is described in combination with the first to sixth embodiments. Figure 1 The embodiment is described, the torque transmission system of the embodiment comprises a planet carrier 13, a fixed ring 10 and a planetary gear system, a recess is formed on the connecting surface of the swing cylinder driving system, the recess is formed in the radial direction of the planet carrier 13, the other end of the sliding block 20 is inserted into the recess, and the height of the side wall of the recess is higher than the height of the frame body of the planet carrier 13; the planet carrier 13 is installed on the planetary gear system through the fixed ring 10.

[0047] In this way, the planet carrier 13 needs to bear a large torque, and its shape is improved to further strengthen the structure. Specifically, the planet carrier 13 is a ring body with three-point positioning, a sleeve is arranged in the middle of the ring body for sleeving the planet carrier snap spring 11 and the planet carrier bearing 12, a rectangular recess is arranged on the three-point positioning ring body, and the height of the rectangular recess is higher than the ring body, which can limit the sliding block 20 and ensure the output of large torque. The other components and connection relationships are the same as any one of the first to fifth embodiments.

[0048] The seventh embodiment is described in combination with the first to sixth embodiments. Figure 1The planetary gear system of the embodiment comprises an outer ring gear 6, gear bearings 8, an output gear shaft 4, planetary gear shafts 7, gear shaft springs 9 and a plurality of planetary gears 5,

[0049] The output gear shaft 4 is coaxially installed in the outer ring gear 6, the plurality of planetary gears 5 are installed in the outer ring gear 6 and engaged with the output gear shaft 4 and the inner teeth of the outer ring gear 6, a planetary gear shaft 7 is inserted on each planetary gear 5, a gear bearing 8 is sleeved between the planetary gear 5 and the planetary gear shaft 7, and the gear shaft spring 9 is installed at one end of the planetary gear shaft 7.

[0050] In this way, the inner ring of the gear bearing 8 is connected with the planetary carrier 13, and the outer ring of the gear bearing 8 is connected with the annular part, which can be connected with the housing through radial screws or outer ring threads. The annular structure is slotted to meet the stroke requirements of the three planetary wheel rods, and the planetary wheel rods are connected with the planetary carrier 13 through the upper protruding cylindrical features of the planetary carrier 13. The other components and connection relationships are the same as any one of embodiments 1 to 6.

[0051] Embodiment eight: combination Figure 1 In this embodiment, the planetary gear 5 is a spoke gear. In this way, the planetary gear is made into a "spoke" structure that is easy to process, so as to reduce the overall weight while ensuring the strength. The other components and connection relationships are the same as any one of embodiments 1 to 7.

[0052] Embodiment nine: combination Figure 1 In this embodiment, the torque transmission system further comprises a planetary carrier spring 11 and a planetary carrier bearing 12, which are sleeved on the planetary carrier 13 and embedded in the inner hole of the fixed ring 10.

[0053] In this way, since the bearing model connected with the housing of the planetary carrier 13 is large in size and heavy in weight, unnecessary load is increased, so a smaller bearing is considered to be used, and the weight can be reduced to about one tenth of the original. Since the upper side of the planetary carrier 13 (such as Figure 1 ) is blocked by the transmission device and is difficult to install, it is selected to be installed on the lower side of the planetary carrier 13.

[0054] Embodiment ten: combination Figures 1-3 In this embodiment, the torque transmission system further comprises a magnetic encoder 2 and an upper end bearing 3, which are sleeved on the output gear shaft 4 and embedded in the middle part of the swing cylinder top cover 1.

[0055] Combination ​ The working principle of the present application is as follows:

[0056] The hydraulic drive large-angle robot joint of the present application is provided with an integrated oil passage for entering the shell from the outside, and the hydraulic oil enters the hollow piston rod via the rotating oil passage joint and the oil delivery shaft, and then enters the two oil cavities from the oil holes on the rod wall of the piston rod and the piston, and pushes the hydraulic cylinder to make linear reciprocating motion. The hydraulic cylinder body is used as a transmission element, and the linear reciprocating motion is converted into reciprocating swing through the hydraulic cylinder path and the eccentric arrangement of the wheel disc. The output rotation is output by the sun gear shaft through the planetary gear speed-up scheme, so as to realize the large-range and large-torque power output of the humanoid robot joint. An oil pressure sensor is installed on the oil passage, and a magnetic encoder is installed on the swing cylinder top cover, so as to realize the sensing and feedback of the system through the integration of multiple sensors.

[0057] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A hydraulically driven large angle robot joint comprising a housing unit, characterized in that: It also includes a torque transmission system and a swing cylinder driving system, the torque transmission system and the swing cylinder driving system are connected and embedded in the shell unit, wherein the swing cylinder driving system provides reciprocating linear swing driving power and is slidingly connected between the input end of the torque transmission system, converts the linear motion of the swing driving power into the torque power source of the torque transmission system, and outputs the torque from the torque transmission system; The swing cylinder driving system includes a hydraulic cylinder body (21) and a sliding block (20), the hydraulic cylinder body (21) is embedded in the swing cylinder shell (14), and two hydraulic oil input ports are arranged on the hydraulic cylinder body (21) and linearly swing in the swing cylinder shell (14), one end of the sliding block (20) is installed on the outer side wall of the middle part of the hydraulic cylinder body (21), and the other end of the sliding block (20) is slidingly connected with the torque transmission system; The swing cylinder driving system further includes two sliding guide assemblies symmetrically arranged on both sides of the hydraulic cylinder body (21), each sliding guide assembly includes an oil supply shaft (17), a sealing ring (18) and a hydraulic cylinder end cover (19), the oil supply shaft (17) is sealingly installed on one side of the hydraulic cylinder body (21) through the sealing ring (18), and the hydraulic cylinder end cover (19) is installed on the side of the hydraulic cylinder body (21); The swing cylinder driving system further includes a hydraulic servo valve (15) and two oil pressure sensors (16), the hydraulic servo valve (15) and the two oil pressure sensors (16) are installed in the swing cylinder shell (14) and connected with the hydraulic cylinder body (21); The torque transmission system includes a planetary gear carrier (13), a fixed ring (10) and a planetary gear train, a recess is formed in the connecting surface of the swing cylinder driving system, the recess is formed in the radial direction of the planetary gear carrier (13), the other end of the sliding block (20) is inserted into the recess, and the height of the side wall of the recess is higher than the height of the frame body of the planetary gear carrier (13); the planetary gear carrier (13) is installed on the planetary gear train through the fixed ring (10); The planetary gear train includes an outer gear ring (6), a gear bearing (8), an output gear shaft (4), a planetary gear shaft (7), a gear shaft clamp spring (9) and a plurality of planetary gears (5), the output gear shaft (4) is coaxially and rotatably installed in the outer gear ring (6), the plurality of planetary gears (5) are installed in the outer gear ring (6) and meshed with the inner teeth of the output gear shaft (4) and the outer gear ring (6), one planetary gear shaft (7) is inserted into each planetary gear (5), and a gear bearing (8) is sleeved between the planetary gear (5) and the planetary gear shaft (7), and the gear shaft clamp spring (9) is installed at one end of the planetary gear shaft (7).

2. The hydraulic drive large rotation robot joint according to claim 1, characterized in that: The shell unit includes a swing cylinder bottom cover (22), a swing cylinder shell (14) and a swing cylinder top cover (1), the swing cylinder bottom cover (22) and the swing cylinder top cover (1) are respectively installed on both sides of the swing cylinder shell (14) in the length direction.

3. The hydraulic drive large rotation robot joint according to claim 2, characterized in that: The planetary gear (5) is a spoke gear.

4. The hydraulic drive large rotation robot joint according to claim 3, characterized in that: The torque transmission system further comprises a planet carrier snap spring (11) and a planet carrier bearing (12), which are sleeved on the planet carrier (13) and embedded in the inner hole of the fixed ring (10).

5. The hydraulic drive large rotation robot joint according to claim 4, characterized in that: The torque transmission system further comprises a magnetic encoder (2) and an upper end bearing (3), which are embedded in the middle part of the swing cylinder top cover (1) after being sleeved on the output gear shaft (4).

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