Low-speed large-torque water hydraulic motor suitable for deep sea mechanical arm

Abstract

The invention discloses a deep sea water hydraulic mechanical arm low-speed large-torque motor which mainly comprises a motor body and a valve flow distribution mechanism, the motor body mainly comprises a crankshaft, a water lubrication bearing assembly, a plunger assembly, a swing cylinder, a shell, a front end cover and a rear end cover, and the valve flow distribution mechanism mainly comprises a valve frame, a valve set, an ejector rod and two cams. The valve frame is used for supporting and protecting internal components, the water-lubricated bearing component realizes full water lubrication when the motor works in a deep sea environment by adopting a bidirectional six-groove structural design, and the valve flow distribution mechanism replaces a traditional low-speed large-torque motor shaft flow distribution or disc flow distribution structure. The problems that a flow distribution mechanism is seriously abraded and short in service life when working for a long time in a marine environment are solved, and the problem that the flow distribution mechanism is prone to failure when driven by a high-pressure water medium is solved. The low-speed large-torque motor of the deep sea water hydraulic mechanical arm has the advantages of being simple in structure, stable in performance, high in power density and high in applicability.

Description

Technical Field

[0001] This invention relates to the field of deep-sea hydraulic actuators, specifically to a low-speed, high-torque water hydraulic motor suitable for deep-sea robotic arms. Background Technology

[0002] Deep-sea equipment is the technological support for building a maritime power and developing the marine economy. Deep-sea robotic arms are important tools for deep-sea resource exploration and development as well as deep-sea engineering construction. The development of new deep-sea robotic arms plays an increasingly important role in improving the level of marine development and utilization and promoting the development of marine industries.

[0003] With the advancement of science and technology, underwater robots and detectors equipped with robotic arms, as well as other deep-sea operational equipment, have become active in many fields such as marine resource development. Hydraulic systems, due to their high power density, have also been widely used in the marine equipment field. Currently, most deep-sea heavy-duty robotic arms are driven by hydraulic systems. However, traditional hydraulic drive systems suffer from serious defects such as oil-water seepage pollution and performance degradation under heavy-duty operation, making it difficult to operate stably for extended periods. Water hydraulic technology is currently recognized as a transformative technology for deep-sea equipment. If seawater is used as the working medium for deep-sea hydraulic robotic arms, it can not only fundamentally solve the problems of pollution and decreased equipment reliability caused by oil-water seepage during deep-sea operations, but also simplify the hydraulic system and achieve green deep-sea equipment. However, the harsh environment of the deep sea and the characteristics of the water medium limit the development of deep-sea water hydraulic technology. Existing low-speed, high-torque water hydraulic motors are all in the research stage. For example, vane-type water hydraulic motors, due to their low pressure rating and small output torque, cannot meet the high-pressure, heavy-duty requirements of deep-sea water hydraulic robotic arms. Currently, no deep-sea heavy-duty water hydraulic robotic arms have been developed. Developing low-speed, high-torque rotary joints for deep-sea hydraulic robotic arms will be of great significance to the development of deep-sea hydraulic equipment.

[0004] Therefore, there is an urgent need to develop a low-speed, high-torque motor suitable for deep-sea hydraulic robotic arms to meet the requirements of deep-sea resource exploration, development, and other long-duration, heavy-load operations. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a low-speed, high-torque motor for deep-sea hydraulic robotic arms. The aim is to design and invent a water-driven low-speed, high-torque motor suitable for the shoulder and wrist joints of deep-sea hydraulic robotic arms, enabling continuous rotation of the end effector. This fundamentally solves the technical problems encountered by traditional hydraulic drive systems in long-term, continuous, heavy-load operations in deep-sea environments, thus contributing to the research and development of deep-sea hydraulic robotic arms. Specifically, a low-speed, high-torque motor suitable for the unique working conditions of deep-sea hydraulic robotic arms was researched and designed. Through research and design of the specific structures and configurations of key components such as the valve distribution mechanism, motor body, and water lubrication components, the motor achieves advantages such as stable performance, compact structure, and full water lubrication, thus enabling its application in deep-sea hydraulic robotic arms.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A low-speed, high-torque motor for a deep-sea hydraulic robotic arm includes a motor body and a valve distribution mechanism docked with the motor body. The motor body includes a crankshaft, a water-lubricated bearing assembly, a plunger assembly, a swing cylinder, a housing, a front end cover, and a rear end cover. The housing has an equal number of shaft holes evenly distributed along its circumference on both sides. An equal number of swing cylinder assemblies and plunger assemblies are installed in each of these shaft holes, with the plunger assemblies located inside the swing cylinder assemblies. A front end cover and a rear end cover with corresponding shaft holes are installed on both sides of the housing port. The crankshaft provides torque to the motor and is located at the center of the motor. The water-lubricated bearing assembly includes a first water-lubricated bearing group and a second water-lubricated bearing group. The first water-lubricated bearing group includes two identical sets of components at the front and rear end covers. Each set of components includes a water-lubricated bearing inner ring, an end face bearing, a water-lubricated bearing outer ring, and a bearing body, which are sequentially distributed radially along the crankshaft. The second water-lubricated bearing group includes two semi-cylindrical mid-section water-lubricated bearings and a bearing seat, which are sequentially distributed radially along the crankshaft in the middle part of the crankshaft. The plunger assembly includes a plunger, a first spring at the top of the plunger, and a plate-shaped water-lubricated bearing at the bottom of the plunger. The swing cylinder, the housing, and the connection points with the front and rear end covers are all supported by bushings. The valve distribution mechanism includes: a valve frame, a valve assembly, a push rod, and two cams; the valve frame is used to support and protect internal components; the valve assembly includes two sets of cone valves with identical structures, and the two cone valves share the same outlet communicating with the hydraulic chamber of the swing cylinder. Each cone valve includes a valve cover, a second spring, a valve core, and a valve seat connected radially in sequence on one side of the housing. The valve seat is an integral structure with three outlets; the push rod is located below the valve core; the two cams are symmetrically mounted vertically on the distribution shaft, which is an integral part of the main journal of the motor crankshaft, and both cams are equipped with ceramic bearings.

[0007] According to one embodiment of the present invention, the swing cylinder further includes a first guide ring and a first Gladius ring arranged sequentially upward from the bottom of the swing cylinder. The first guide ring is used to provide guidance for the movement of the plunger, and the first Gladius ring is used to dynamically seal the gap between the swing cylinder and the plunger. Swing cylinder bushings are installed on both sides of the swing shaft of each swing cylinder.

[0008] According to one embodiment of the present invention, the cone valve further includes a sealing ring and a second Glyd ring installed sequentially upward from the bottom of the valve core; the valve core and the push rod have a connecting hole for connecting the cavities above and below the valve core; the valve core also includes a third spring below it, the third spring being used to ensure that the lower end of the push rod is always in contact with the outer circle of the deep groove ball bearing on the cam, so as to prevent the push rod from separating from the deep groove ball bearing when the rotation speed is high, which would cause the valve to open prematurely or close delayed.

[0009] According to one embodiment of the present invention, the two cams are installed with a 180° phase difference, and the two cams are connected to the crankshaft via a flat key.

[0010] According to one embodiment of the present invention, the valve distribution mechanism further includes a first tail plate and a second tail plate connected in sequence on the side away from the rear end cover. The liquid inlet and liquid outlet of the valve distribution mechanism are completed through two annular flow channels formed by the two tail plates, the rear end cover and the valve frame.

[0011] According to one embodiment of the present invention, the inlet and outlet of the distribution valve assembly are sealed by a first O-ring, the gap between the first distribution pipe and the rear end cover is sealed by a fourth O-ring, and the two annular flow channels are sealed by a second O-ring and a third O-ring.

[0012] According to one embodiment of the present invention, the motor is a double-row rotary radial piston motor, and each row of the motor is provided with an odd number of pistons of three or more.

[0013] According to one embodiment of the present invention, the housing is fixed to the front and rear end covers by a first countersunk screw and a second countersunk screw; the flow distribution valve is fixed by a slot on the valve frame, and the valve flow distribution mechanism is connected to the rear end cover of the motor by a long bolt.

[0014] According to one embodiment of the present invention, the bushing is made of PEEK material and the ceramic bearing is a Si3N4 ceramic bearing.

[0015] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: 1. The low-speed, high-torque motor for deep-sea hydraulic robotic arms provided by this invention replaces the traditional shaft or disc distribution structure with a valve distribution mechanism. This reduces the number of mating pairs, significantly improving the motor's volumetric efficiency. It avoids the problem of low-speed, high-torque motors easily failing when using water as the driving medium, as well as the problem of severe wear on the distribution shaft or distribution disc due to impurities such as suspended sand after prolonged use in the marine environment, leading to a continuous increase in the distribution gap and shortening the motor's lifespan. Furthermore, by adopting a bidirectional six-groove structure for the water-lubricated bearing, the motor achieves full water lubrication when operating in the deep-sea environment. In addition, this motor optimizes the pipe placement of the hydraulic robotic arm, simplifies the distribution method, and facilitates integration with other joints.

[0016] 2. The low-speed, high-torque motor for the deep-sea hydraulic robotic arm provided by this invention adopts a double-row plunger structure, which greatly reduces the radial dimension of the motor with the same power and pressure level. This makes the radial dimension of the motor at the target power compatible with the structural dimensions of the other joints of the deep-sea robotic arm, resulting in a more harmonious structure.

[0017] 3. The low-speed, high-torque motor for deep-sea hydraulic robotic arms provided by this invention, by selecting the best materials for the PEEK bushing and Si3N4 ceramic bearing pair, greatly reduces the bearing's friction loss and temperature rise while increasing the bearing's load-bearing capacity. It replaces the traditional oil-lubricated bearing with a double-sided six-groove water-lubricated bearing, and achieves full water lubrication of the motor when working in the deep-sea environment by taking advantage of the deep-sea environmental pressure, thereby improving the overall performance and lifespan of the motor under deep-sea lubrication conditions. Attached Figure Description

[0018] Figure 1 This is a front view of a low-speed, high-torque motor for a deep-sea hydraulic robotic arm according to an embodiment of the present invention.

[0019] Figure 2 This is a cross-sectional schematic diagram I of a low-speed, high-torque motor for a deep-sea hydraulic robotic arm according to an embodiment of the present invention. Figure 1 (Bottom view)

[0020] Figure 3 This is a cross-sectional schematic diagram II (cross-sectional view along the line connecting the two distribution interfaces) of a low-speed, high-torque motor for a deep-sea hydraulic robotic arm in an embodiment of the present invention.

[0021] Figure 4 This is a crankshaft end face view of a low-speed, high-torque motor for a deep-sea hydraulic robotic arm according to an embodiment of the present invention. Figure 1 (Right view of the end face).

[0022] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1. Crankshaft; 2. Inner ring of water-lubricated bearing; 3. End face bearing; 4. Outer ring of water-lubricated bearing; 5. Bearing body; 6. Front end cover; 7. Housing; 8. Middle section water-lubricated bearing; 9. Bearing seat; 10. Swing cylinder; 11. First guide ring; 12. First Glyd ring; 13. Plunger; 14. First spring; 15. Plate-shaped water-lubricated bearing; 16. Swing cylinder bushing; 17. Rear end cover; 18. First O-ring; 19. Valve cover; 20. Second spring; 21. Valve seat; 22. Valve core; 23. Sealing ring. 24. Second Glyd ring; 25. Push rod; 26. Third spring; 27. Deep groove ball bearing; 28. Bearing retainer ring; 29. ​​Cam; 30. First tail plate; 31. Second tail plate; 32. Second O-ring; 33. Third O-ring; 34. Long bolt; 35. First spring washer; 36. Valve bracket; 37. Guide tube; 38. First countersunk screw; 39. Second countersunk screw; 40. Third countersunk screw; 41. First distribution tube; 42. Fourth O-ring; 43. First flat key; 44. Second flat key. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0024] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more. The terms "first," "second," "third," and "fourth," etc., in the specification of this invention are used to distinguish different objects, not to describe a specific order.

[0025] This invention provides a low-speed, high-torque motor for deep-sea hydraulic robotic arms. This fully water-lubricated, high-torque motor, driven by a water medium and capable of bidirectional rotation, is suitable for deep-sea hydraulic robotic arms. It uses water pressure instead of hydraulic pressure to drive the motor, enabling it to meet the high-pressure, heavy-load requirements of deep-sea robotic arms and fulfilling the task requirements of deep-sea resource exploration, sampling, and carrying other work tools to complete long-term, heavy-load underwater operations. By using seawater as the working medium, the deep-sea hydraulic robotic arm fundamentally solves the problems of pollution and reduced equipment reliability caused by oil-water seepage during deep-sea operations. It also simplifies the hydraulic system and achieves greening of deep-sea equipment.

[0026] The following description, in conjunction with the accompanying drawings and examples, provides a more detailed account of the low-speed, high-torque motor for the deep-sea hydraulic robotic arm provided by this invention.

[0027] like Figure 1 As shown, the low-speed, high-torque motor for the deep-sea hydraulic robotic arm provided by this invention can be used as the shoulder joint of the deep-sea robotic arm. It mainly consists of a motor body A and a valve distribution mechanism B. In this example, the motor body is a double-row five-plunger radial plunger motor. The valve distribution mechanism includes 10 valve groups and distribution cam assemblies, etc., used to control the inlet and outlet of each corresponding swing cylinder. The valve distribution mechanism B can be connected to the motor body A by bolts.

[0028] like Figure 2 and Figure 3As shown, the low-speed, high-torque motor of the deep-sea hydraulic robotic arm provided by this invention outputs torque through crankshaft 1. The water-lubricated bearing inner ring 2, end face bearing 3, water-lubricated bearing outer ring 4, and bearing body 5 together form a water-lubricated bearing assembly one. During installation, water-lubricated bearing assembly one should first be installed into the front end cover 6 and rear end cover 17. After the remaining components of the motor body A are fully installed, the front end cover 6 and rear end cover 17 should be installed and tightened. Finally, it is fixed to the housing 7 using the first countersunk screw 38 and the second countersunk screw 39 respectively. The middle section water-lubricated bearing 8 is semi-cylindrical. Two middle section water-lubricated bearings 8 need to be installed into the bearing seat 9 through an interference fit to form water-lubricated bearing assembly two. During installation, water-lubricated bearing assembly two should first be installed into the middle section of crankshaft 1, and then passed through the housing 7 together with crankshaft 1 and fixed. Each swing cylinder 10 is equipped with a first guide ring 11 and a first Gladius ring 12. The first guide ring 11 provides guidance for the movement of the plunger 13, and the first Gladius ring 12 is used to dynamically seal the gap between the swing cylinder 10 and the plunger 13. Swing cylinder bushings 16 are installed on both sides of the swing shaft of each swing cylinder 10. A first spring 14 is installed on the top of each plunger 13. A plate-shaped water-lubricated bearing 15 is embedded at the bottom of each plunger 13. During installation, the plunger assembly (plunger 13, first spring 14, plate-shaped water-lubricated bearing 15) is first installed into the swing cylinder assembly (swing cylinder 10, first guide ring 11, first Gladius ring 12, swing cylinder bushing 16) and then installed together into the housing 7. The relative position with the crankshaft 1 is adjusted so that the plate-shaped water-lubricated bearing 15 is in contact with the crank of the crankshaft 1. In this example, the motor body is a double-row five-plunger swing cylinder radial plunger motor. Therefore, the distribution mechanism contains a total of 10 valve groups. Each liquid distribution valve group is evenly distributed in a ring around the valve frame 36 and is on the same axial plane as the swing shaft of the swing cylinder 10. Each group of liquid distribution valves controls the inlet and outlet of one swing cylinder 10. Each valve group consists of two cone valves. Each cone valve consists of a valve cover 19, a second spring 20, a valve seat 21, a valve core 22, a sealing ring 23, and a Glyd ring 24. The opening and closing of the distribution valve is controlled by the push rod 25. The valve seats 21 of the two cone valves are an integral structure. The two cone valves share the same outlet and communicate with the hydraulic chamber of the swing cylinder 10. Since the swing cylinder 10 can swing around the swing shaft, the connection with the outlet of the distribution valve is sealed with the second Glyd ring 24. The row of swing cylinders 10 far away from the valve distribution mechanism B needs to add a guide pipe 37 to realize the distribution. A connecting hole is provided on the valve core 22 and the push rod 25 to connect the cavities above and below the valve core 22, so as to balance the hydraulic pressure on the valve core 22. The cavity above the valve core 22 is sealed by the second Glyd ring 24, and the cavity below the valve core 22 is sealed by the second Glyd ring 24 and the valve port. A cam 29 is installed on the distribution shaft integrated with the main journal of the motor crankshaft 1. The cam 29 rotates with the crankshaft 1, and drives the push rod 25 to directly drive the valve core 22 to control the opening and closing of the valve port.The cam 29 is equipped with a deep groove ball bearing 27 to reduce the lateral force on the push rod 25, prevent uneven wear, and reduce wear on the bottom of the push rod 25 to extend the service life of the distribution valve assembly. The second spring 20 at the top of the valve core 22 provides the return thrust and sealing pressure of the valve port to maintain a reliable seal. The spring 26 at the lower end of the push rod 25 ensures that the lower end of the push rod 25 is always in contact with the outer circle of the deep groove ball bearing 27 on the cam 29, preventing the push rod 25 from separating from the deep groove ball bearing 27 at high speeds, which would cause the valve port to open prematurely or close late. The two cams 29 have a 180° phase difference during installation. The opening and closing states of the two distribution valves on the motor crankshaft 1 at the same rotation angle are always opposite, and each valve is open or closed for half of the time during one revolution of the motor. Therefore, the two cone valves have the same working principle and similar structure. When one is used as an inlet valve, the other is used as a drain valve. Thus, when the valve assemblies work together, the motor can rotate in both directions. The inlet and outlet of each distribution valve group are connected by two annular flow channels formed by the first tail plate 30, the second tail plate 31, the valve frame 36, and the rear end cover 17 of the motor. The inlet and outlet of the entire motor can be led to the first tail plate 30 of the motor through the first distribution pipe 41. The two annular flow channels are sealed by the second O-ring 32 and the third O-ring 33. The inlet and outlet of the distribution valve group are sealed by the first O-ring 18. The gap between the first distribution pipe 41 and the rear end cover 17 is sealed by the fourth O-ring 42.

[0029] Furthermore, each group of distribution valves can be fixed by the slots on the valve frame 36, and the first tail plate 30 and the second tail plate 31 can be connected and fixed by countersunk screws 40. The valve distribution mechanism B can be connected to the rear end cover 17 of the motor by long bolts 34. At the same time, the first tail plate 30 and the second tail plate 31 can press each sealing surface, and cooperate with the corresponding sealing components to ensure that each flow channel is reliably sealed.

[0030] like Figure 4 As shown, since there is a 36° phase angle difference between the two rows of plungers, when the included angle of crankshaft 1 is 0°, it is equivalent to a single row of ten-plunger motors, while when the included angle of crankshaft 1 is 180°, it is equivalent to two single row of five-plunger motors connected in series. Preferably, the included angle between the two crank sections of crankshaft 1 is 18°, which is equivalent to two single row of five-plunger motors connected in series with an 18° phase difference in output torque. The overall torque fluctuation rate will be greatly reduced. The distribution shaft of valve distribution mechanism B is integrated with crankshaft 1 and is connected to two cams 29 respectively through the first flat key 43 and the second flat key 44.

[0031] The present invention achieves the following beneficial effects: It can be driven by hydraulic pressure and achieves full water lubrication of the motor, avoiding pollution to the marine environment. Structurally, the double-row plunger structure significantly reduces the radial dimension of the motor, making it better adaptable to various types of deep-sea robotic arms. By optimizing the phase difference of the double-row plungers and the angle between the two crankshaft segments and the center of the main journal, the pulsation rate of parameters such as flow rate and torque of the hydraulic motor is reduced compared to a single-row plunger, resulting in more stable motor performance.

[0032] Those skilled in the art will readily understand that the above description is merely an embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-speed, high-torque motor for a deep-sea hydraulic robotic arm, characterized in that, The device includes a motor body and a valve distribution mechanism that interfaces with the motor body. The motor body includes a crankshaft, a water-lubricated bearing assembly, a plunger assembly, a swing cylinder, a housing, a front end cover, and a rear end cover. The housing has an equal number of shaft holes evenly distributed along its circumference on both sides. An equal number of swing cylinder assemblies and plunger assemblies are installed in each of these shaft holes, with the plunger assemblies located inside the swing cylinder assemblies. A front end cover and a rear end cover with corresponding shaft holes are installed on both sides of the housing port. The crankshaft provides torque to the motor and is located at the center of the motor. The water-lubricated bearing assembly includes a first water-lubricated bearing group and a second water-lubricated bearing group. The first water-lubricated bearing group includes two identical sets of components at the front and rear end covers. Each set of components includes a water-lubricated bearing inner ring, an end face bearing, a water-lubricated bearing outer ring, and a bearing body, which are sequentially distributed radially along the crankshaft. The second water-lubricated bearing group includes two semi-cylindrical mid-section water-lubricated bearings and a bearing seat, which are sequentially distributed radially along the crankshaft in the middle part of the crankshaft. The plunger assembly includes a plunger, a first spring at the top of the plunger, and a plate-shaped water-lubricated bearing at the bottom of the plunger. The swing cylinder, the housing, and the connection points with the front and rear end covers are all supported by bushings. The valve distribution mechanism includes: a valve frame, a valve assembly, a push rod, and two cams; the valve frame is used to support and protect internal components; the valve assembly includes two sets of cone valves with identical structures, and the two cone valves share the same outlet communicating with the hydraulic chamber of the swing cylinder. Each cone valve includes a valve cover, a second spring, a valve core, and a valve seat connected radially in sequence on one side of the housing. The valve seat is an integral structure with three outlets; the push rod is located below the valve core; the two cams are symmetrically mounted vertically on the distribution shaft, which is an integral part of the main journal of the motor crankshaft, and both cams are equipped with ceramic bearings.

2. The low-speed, high-torque motor for a deep-sea hydraulic robotic arm as described in claim 1, characterized in that, The swing cylinder also includes a first guide ring and a first Gladius ring arranged sequentially upwards from the bottom of the swing cylinder. The first guide ring is used to guide the movement of the plunger, and the first Gladius ring is used to dynamically seal the gap between the swing cylinder and the plunger. Swing cylinder bushings are installed on both sides of the swing shaft of each swing cylinder.

3. The low-speed, high-torque motor for a deep-sea hydraulic robotic arm as described in claim 1, characterized in that, The cone valve also includes a sealing ring and a second Glyd ring installed sequentially upwards from the bottom of the valve core; the valve core and the push rod have connecting holes for connecting the cavities above and below the valve core; the valve core also includes a third spring below it, which is used to keep the lower end of the push rod in contact with the outer circle of the deep groove ball bearing on the cam, so as to prevent the push rod from separating from the deep groove ball bearing when the speed is high, which would cause the valve to open prematurely or close late.

4. The low-speed, high-torque motor for a deep-sea hydraulic robotic arm as described in claim 1, characterized in that, The two cams are installed with a 180° phase difference, and the two cams are connected to the crankshaft via a flat key.

5. The low-speed, high-torque motor for a deep-sea hydraulic robotic arm as described in claim 1, characterized in that, The valve distribution mechanism also includes a first tail plate and a second tail plate connected in sequence on the side away from the rear end cover. The liquid inlet and outlet of the valve distribution mechanism are completed through two annular flow channels formed by the two tail plates, the rear end cover, and the valve frame.

6. The low-speed, high-torque motor for a deep-sea hydraulic robotic arm as described in claim 5, characterized in that, The inlet and outlet of the distribution valve assembly are sealed by a first O-ring, the gap between the first distribution pipe and the rear end cover is sealed by a fourth O-ring, and the two annular flow channels are sealed by a second O-ring and a third O-ring.

7. The low-speed, high-torque motor for a deep-sea hydraulic robotic arm as described in claim 1, characterized in that, The motor is a double-row rotary radial piston motor, with each row of the motor having an odd number of pistons, greater than or equal to three.

8. The low-speed, high-torque motor for a deep-sea hydraulic robotic arm as described in claim 1, characterized in that, The housing is fixed to the front and rear end covers using a first countersunk screw and a second countersunk screw; the distribution valve is fixed by a slot on the valve frame, and the valve distribution mechanism is connected to the rear end cover of the motor by a long bolt.

9. The low-speed, high-torque motor for a deep-sea hydraulic robotic arm as described in claim 1, characterized in that, The bushing is made of PEEK material, and the ceramic bearing is a Si3N4 ceramic bearing.

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