Closed numerical control hydraulic pump and robot

Abstract

The utility model provides a closed type numerical control hydraulic pump and a robot. The closed type numerical control hydraulic pump comprises a sub-pump body and at least one mother pump body, and the sub-pump body is connected with the mother pump body through a hose to form a closed type space hydraulic cavity; the mother pump body is driven by a servo motor to drive the son pump bodies to move synchronously. The oil pump comprises a closed single pump body and a double pump body, and under the condition that the oil amount is certain, a mother pump body drives a son pump body to continuously reciprocate; the mounting position of the sub-pump body is flexible and is not limited by the size of a space range; the device is easy to carry and can be remotely controlled to move; the output direction is free, the fixed-point staying position is accurate, energy consumption is small, and safety and reliability are achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of numerical control hydraulic pump, in particular to a closed numerical control hydraulic pump and a robot provided with the same. BACKGROUND

[0002] At present, the traditional hydraulic pump is mostly large in size and of single-pump open structure, which cannot be installed in narrow space and is not easy to carry. The single-pump open hydraulic pump is greatly affected by working conditions, and once its position is fixed, its output direction is single, and it can only reciprocate unidirectionally along the direction of the pump body connection position, and cannot control the robot or remote objects. In addition, the conventional hydraulic pump has power loss when staying at a fixed position under stress.

[0003] The maximum arm strength of the humanoid robot on the market is currently 20 kg, which is not enough to hold a disabled human body, so the use of the closed numerical control hydraulic pump can make a single arm hold 50 kg of weight, and the average weight of a person is within 100 kg. Moreover, the existing hydraulic cylinders are poor in portability, which makes it difficult to control the mechanical arm flexibly. In addition, the existing humanoid robots are not designed with a spine, which affects the range of the humanoid robot's gravity center adjustment. The closed numerical control hydraulic pump can remotely control the micro hydraulic cylinder to adjust the spine joint, thereby adjusting the posture of the humanoid robot and achieving the anthropomorphic adjustment of the gravity center. SUMMARY

[0004] The application provides a closed numerical control hydraulic pump and a robot, which solves the technical problems of the single-pump open structure of the existing hydraulic pump, such as single output direction, large size and inability to work directly in narrow space.

[0005] To solve at least one of the above technical problems, the application adopts the following technical scheme:

[0006] A closed numerical control hydraulic pump comprises a sub-pump body and at least one mother pump body, the sub-pump body is connected to the mother pump body through a hose to form a closed spaced hydraulic chamber, and the mother pump body is driven by a servo motor to drive the sub-pump body to move synchronously.

[0007] Further, the servo motor is directly connected to the mother pump body through a speed reducer, the number of hoses is two, and the speed reducer is connected to a mother piston in the mother pump body through a ball screw.

[0008] Further, the number of mother pump bodies is one or two, and the number of sub-pump bodies is one, and each hydraulic chamber in the mother pump body and the sub-pump body is provided with a rodless chamber end and a rod chamber end.

[0009] Further, when the mother pump body is one, the servo motor is connected with the mother pump body through a speed reducer of single output shaft; the diameter of the hydraulic chamber of the sub pump body is same with the diameter of the hydraulic chamber of the mother pump body.

[0010] Further, one of the hoses is respectively connected with the rodless chamber end of the hydraulic chamber in the sub pump body and the mother pump body; the other hose is respectively connected with the rod chamber end of the hydraulic chamber in the sub pump body and the mother pump body.

[0011] Further, when the mother pump body is two, including one mother pump body with short cylinder and one mother pump body with long cylinder; the servo motor is respectively connected with the two mother pump bodies through a speed reducer of double output shaft.

[0012] Further, one of the hoses is respectively connected with the rodless chamber end of the hydraulic chamber in the sub pump body and the mother pump body with short cylinder; the other hose is respectively connected with the rod chamber end of the hydraulic chamber in the sub pump body and the mother pump body with long cylinder.

[0013] Further, the diameter of the short cylinder is larger than the diameter of the long cylinder.

[0014] A robot, on its arm, is equipped with a closed numerical control hydraulic pump as described above, the sub pump body is arranged on the large arm, the fixed seat at the tail of the sub pump body is fixed on the large arm near the shoulder bone, and the suspended end is pivoted on the connecting shaft of the large arm and the small arm through a pin shaft.

[0015] Further, the mother pump body and the sub pump body are arranged on the same side of the large arm or away from the large arm.

[0016] The closed numerical control hydraulic pump designed in the application includes a closed single pump body and a double pump body, under the condition of constant oil quantity, the sub pump body is continuously moved back and forth by the mother pump body; the installation position of the sub pump body is flexible and is not limited by the size of the space range; and it is easy to carry and can be remotely controlled; not only the output direction is free, but also the fixed point staying position is accurate, the energy consumption is small, and it is safe and reliable. The application also proposes a robot equipped with the closed numerical control hydraulic pump. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is the front view of the double pump closed numerical control hydraulic pump in the application;

[0018] Figure 2 is Figure 1 A-A sectional view in

[0019] Figure 3 is the top view of the double pump closed numerical control hydraulic pump in the application;

[0020] Figure 4 This is a front view of the single-pump enclosed CNC hydraulic pump in this application;

[0021] Figure 5 This is a cross-sectional view of the single-pump enclosed CNC hydraulic pump in this application;

[0022] Figure 6 This is an example image of a robotic arm controlled by a dual-pump closed-loop CNC hydraulic pump;

[0023] Figure 7 This is an example diagram of another robotic arm controlled by a dual-pump closed-loop CNC hydraulic pump.

[0024] In the picture:

[0025] 10. Sub-pump body; 11. Sub-piston; 12. Fixed seat

[0026] 13. Pin shaft; 20. Mother pump body; 21. Mother piston

[0027] 22. Ball screw 23. Guide key 24. Short cylinder block

[0028] 25. Long cylinder body; 30. Flexible hose; 40. Servo motor

[0029] 50, speed reducer; 60, boom; 70, forearm

[0030] 80. Axonal bone A. Rodless end B. Rod-type end

[0031] C. Rodless cavity end D. Rod-type cavity end E. Rodless cavity end Detailed Implementation

[0032] The present application will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0033] This embodiment proposes a closed-loop CNC hydraulic pump, such as... Figures 1-5 As shown, the system includes a sub-pump body 10 and at least one mother pump body 20. The sub-pump body 10 is connected to the mother pump body 20 via a hose 30 to form a closed, airtight hydraulic chamber. The hydraulic oil volume in the hydraulic chambers of both the sub-pump body 10 and the mother pump body 20 is constant. The mother pump body 20 is driven by a servo motor 40 to synchronously move the sub-pump body 10. Thus, the mother pump body 20 indirectly controls the sub-pump body 20 to perform reciprocating motion in any direction based on a user-defined setting. This design is not only portable but also allows for hose length adjustment based on actual working conditions, adapting to the operation of the sub-pump body 10 at any distance. This closed-loop CNC hydraulic pump is not limited by spatial size, can be remotely controlled, has free output direction, precise stationary position, low energy consumption, and is safe and reliable.

[0034] In the present application, the servo motor 40 is directly connected with the mother pump body 20 through the speed reducer 50, and the speed reducer 50 is connected with the mother piston 21 in the mother pump body 20 through the ball screw 22. The servo motor 40 drives the speed reducer 50 to drive the ball screw 22 to drive the mother piston 21 to push the hydraulic oil in the mother pump body 20, and the hydraulic oil is pressed to be injected into the cylinder in the child pump body 10 through the hose 30, and then the child piston 11 in the child pump body 10 can be driven to move.

[0035] In the present application, the number of the mother pump body 20 can be one, as shown in Figures 4-5 , or two, as shown in Figures 1-3 . No matter how many the number of the mother pump body 20 is, the number of the child pump body 10 is only one, and the number of the hose 30 is also only two, and the length of the hose 30 can be determined according to the actual situation. The hydraulic chamber in each of the mother pump body 20 and the child pump body 10, that is, the hydraulic cylinder, is provided with a rodless chamber end and a rod chamber end; the hose 30 is connected to the rodless chamber end / rod chamber end in the hydraulic chamber of the child pump body 10 and the rodless chamber end / rod chamber end in the hydraulic chamber of the mother pump body 20, respectively.

[0036] As shown in Figures 1-3 , when the number of the mother pump body 20 is two, including one mother pump body 20 with a short cylinder 24 and one mother pump body 20 with a long cylinder 25, wherein the diameter of the short cylinder 24 is greater than the diameter of the long cylinder 25, and the volume of the hydraulic chamber in the short cylinder 24 is greater than the volume of the hydraulic chamber in the long cylinder 25, and thus the amount of oil stored in the short cylinder 25 is greater than the amount of oil stored in the long cylinder 25. This is because the rodless chamber end A of the hydraulic chamber in the child pump body 10 is communicated with the rodless chamber end C in the short cylinder 24 through the hose 30; the rod chamber end B of the hydraulic chamber in the child pump body 10 is communicated with the rodless chamber end E of the long cylinder 25. For the child pump body 10, although the internal diameters of the hydraulic chambers are the same, the oil amount required at the rodless chamber end A is greater than the oil amount at the rod chamber end B, that is, the oil amount required at the rodless chamber end A in the child pump body 10 is greater than the oil amount at the rod chamber end B.

[0037] As shown in Figure 3 , the servo motor 40 is connected with the two mother pump bodies 20 through the speed reducer 50 with double output shafts, wherein the short cylinder 24 is connected with the forward output shaft of the speed reducer 50 through the ball screw 22, and the long cylinder 24 is connected with the reverse output shaft of the speed reducer 50 through the ball screw 22. Based on different fixed scenarios, guide keys 23 for facilitating installation and fixation can be arranged outside the pump bodies of the two mother pump bodies 20.

[0038] From Figure 3As can be seen, the servo motor 40 is connected with the speed reducer 50, the speed reducer 50 is connected with the ball screw 22, and the nut moving on the ball screw 22 is the female piston 21. The servo motor 40 can be preset with the output torque through the PLC controller, and the motor encoder arranged thereon can also record the rotation angle and rotation number of the servo motor in real time, and the rotation position of the ball screw 22 can be determined without zero reset.

[0039] Meanwhile, after the parameters of the servo motor 50 are input in advance on the PLC controller, the servo motor 50 can adjust the output torque in real time, so as to ensure that the thrust of the female piston 21 driven by the ball screw 22 matches the system load. Moreover, the servo motor 40 has a self-locking function, and can also automatically lock the position of the ball screw when power is off, so as to avoid the hydraulic cylinder from being retracted due to gravity.

[0040] Further, the linear motion of the ball screw 22 is directly converted into the change of the volume of the pump cavity, so that the precise displacement transmission of the hydraulic oil is realized by driving the female piston 21 to move. Meanwhile, based on the incompressibility of the hydraulic oil, the linear transmission of displacement->pressure->actuator thrust can be ensured. Moreover, through the reverse motion of the two ball screws, the two pump bodies can be rotated in opposite directions to compensate, so as to eliminate the risk of hydraulic cylinder shaking caused by the discontinuity of hydraulic oil flow.

[0041] The double-pump closed numerical control hydraulic pump, the volume of the chamber with a rod in the sub-pump body 10 and the volume of the chamber without a rod are respectively communicated with the absolutely closed chamber volume in the two female pump bodies 20, the servo motor 40 drives the speed reducer 50 of the opposite double-output shaft to rotate, the speed reducer 50 drives the two ball screws to rotate in opposite directions, and the two nuts as the female pistons 21 and matched with the ball screws 22 move in opposite directions, so that the hydraulic oil with pressure in the chambers of the two female pump bodies 20 is in the state of simultaneous discharge and recovery, so as to drive the sub-pump body 10 connected with the two female pump bodies 20 to work.

[0042] As Figure 3As shown, after receiving the controller's command, the servo motor 40 rotates in the forward direction according to the preset output torque, and then drives the ball screw 22 in the short cylinder 24 to rotate through the reducer 50, while the long cylinder 25 remains stationary. The reducer 50 drives the female piston 21 in the short cylinder 24 to move from the rod end B to the rodless end A, that is, to move towards the tail end of the cylinder in the short cylinder 24. When the female piston 22 in the short cylinder 24 moves towards the rodless end A, the female piston 22 pushes the hydraulic oil in the cavity where the rodless end A of the short cylinder 24 is located through the hose 30 from the rodless end A in the short cylinder 24 into the rodless end C in the cylinder of the sub-pump body 10. Under the action of pressurized oil, the sub-piston 11 in the sub-pump body 10 moves from the rodless end C to the rod end B in the cylinder of the sub-pump body 10. Then, the hydraulic oil in the cylinder where the rod end D of the sub-pump body 10 is located is pushed by the sub-piston 11 and discharged from the hydraulic cavity where the rod end D of the sub-pump body 10 is located through another hose 30 into the hydraulic cavity where the rodless end E of the long cylinder 25 is located, thereby completing the advancing operation of the sub-piston 11.

[0043] When it is necessary to control the retraction of the sub-piston 11 in the sub-pump body 10, after receiving the retraction command from the controller, the servo motor 30 starts to rotate in reverse and rotates according to the preset output torque. Then, through the reducer 50, it drives the ball screw 22 to rotate, thereby driving the female piston 21 in the long cylinder 25 to move back towards the rodless end E, that is, towards the side of the long cylinder 25 closer to the tail of the cylinder. At this time, the short cylinder 24 remains stationary. When the female piston 22 in the long cylinder 25 moves towards the rodless end E, the female piston 22 pushes the hydraulic oil in the long cylinder 25 through the hose 30 from the rodless end E of the long cylinder 25 into the cavity where the rod end D of the sub-pump body 10 is located. Under the action of pressurized oil, the sub-piston 11 in the sub-pump body 10 moves from the rod end D to the rodless end C. Then, the sub-piston 11 can push the hydraulic oil in the cavity where the rodless end C is located through the hose 30 from the rodless end C in the sub-pump body 10 into the cavity at the rodless end A in the short cylinder 24, thereby completing the retraction operation of the sub-piston 11.

[0044] like Figures 4-5 As shown, when there is only one mother pump body 20, the servo motor 40 is connected to the mother pump body 20 through a reducer 50 with a single output shaft; at the same time, two hoses 30 are respectively connected to the same end side of the daughter pump body 10 and the mother pump body 20. Specifically, one hose 30 is connected to the rodless end of the hydraulic chamber in both the daughter pump body 10 and the mother pump body 20, that is, it is connected to the rodless end of the daughter pump body 10 and the rodless end of the mother pump body 20 respectively; the other hose 30 is connected to the rod end of the hydraulic chamber in both the daughter pump body 10 and the mother pump body 20, that is, it is connected to the rod end of the daughter pump body 10 and the rod end of the mother pump body 20 respectively.

[0045] As shown in Figure 5 the servo motor 40 is electrically connected with an external PCL controller (omitted in the drawing), which starts to rotate in the positive direction and rotates according to the preset output torque after receiving the instruction of the controller, and then drives the ball screw 22 to rotate through the speed reducer 50, so as to drive the mother piston 21 in the mother pump body 20 to move out to the side of the rodless cavity end A, that is, to move to the side away from the tail of the cylinder body in the mother pump body 20. When the mother piston 22 moves from the rod cavity end B to the rodless cavity end A, the hydraulic oil in the cavity where the rodless cavity end A of the mother pump body 20 is located is pushed by the mother piston 22 to be discharged from the rodless cavity end A to the rodless cavity end C in the cylinder body of the child pump body 10 through the hose 30. Under the action of the pressure oil, the child piston 11 in the child pump body 10 moves from the rodless cavity end C to the rod cavity end D in the cylinder body of the child pump body 10, and then the hydraulic oil in the hydraulic cavity of the child pump body 10 is pushed by the child piston 11 to be discharged from the rod cavity end D to the rod cavity end B in the hydraulic cavity of the mother pump body 20 through the other hose 30, thereby completing the advancing operation of the child piston 11.

[0046] When it is necessary to control the child piston 11 in the child pump body 10 to retreat, the servo motor 30 starts to rotate in the reverse direction and rotates according to the preset output torque after receiving the retreat instruction of the controller, and then drives the ball screw 22 to rotate through the speed reducer 50, so as to drive the mother piston 21 in the mother pump body 20 to retreat and move to the side of the rod cavity end B, that is, to move to the side away from the tail of the cylinder body in the mother pump body 20. When the mother piston 22 moves to the side of the rod cavity end B, the hydraulic oil in the cylinder body of the mother pump body 20 is pushed by the mother piston 22 to be discharged from the rod cavity end B in the hydraulic cavity of the mother pump body 20 to the rod cavity end D in the cylinder body of the child pump body 10 through the hose 30 close to the speed reducer 50. Under the action of the pressure oil, the child piston 11 in the child pump body 10 moves from the rod cavity end D to the rodless cavity end C in the cylinder body thereof, and then the hydraulic oil in the hydraulic cavity of the child pump body 10 is pushed by the child piston 11 to be discharged from the rodless cavity end C to the rodless cavity end A in the hydraulic cavity of the mother pump body 20 through the hose 30 away from the speed reducer 50, thereby completing the retreat operation of the child piston 11.

[0047] In this embodiment, the cylinder diameter of the sub-pump body 10 is the same as that of the mother-pump body 20, and the diameters of the sub-piston 11 and the mother-piston 21 are the same. Based on the incompressibility of the hydraulic oil, the quantitative hydraulic oil is continuously circulated in and out of the hydraulic cavity intercommunicating between the sub-pump body 10 and the mother-pump body 20, so that the movements of the sub-piston 11 and the mother-piston 21 are synchronous. When the mother-piston 21 advances in the cylinder of the mother-pump body 20 by a certain distance, the sub-piston 11 advances in the cylinder of the sub-pump body 10 by the same distance. Correspondingly, when the mother-piston 21 retreats in the cylinder of the mother-pump body 20 by a certain distance, the sub-piston 11 retreats in the cylinder of the sub-pump body 10 by the same distance. At the same time, the servo motor has a self-locking function, so that the mounted stationary state at any position can be effectively controlled, the sub-piston 21 can be accurately positioned, and the fixed-point stay is realized.

[0048] Whether it is a single mother-pump body or a double mother-pump body, the suspended end of the sub-piston 11 is connected with the pin shaft 13, and the pin shaft 13 is provided with a mounting hole which can be externally connected and pivoted. As shown in Figures 1-3 , the end of the sub-piston 11 is connected with the pin shaft 13; as shown in Figures 4-5 , the end of the sub-piston 11 is not connected with the pin shaft 13, which is the original structure, and it can also be movably connected with the pin shaft 13 (omitted in the drawings). Correspondingly, the end part of the rodless cavity end C in the sub-pump body 10 is provided with a fixing seat 12 for fixing. This fixing seat 12, like the pin shaft 13, is movably connected with the cylinder of the sub-pump body 10, and can be connected at the tail of the cylinder of the sub-pump body 10 when needed, as shown in Figures 1-3 , and can be detached when not needed, as shown in Figures 4-5 . Through the pin shaft 13 and the fixing seat 12, the sub-pump body 10 can be integrally connected with the installed part, so that the installed part can be moved by the sub-pump body 10.

[0049] The closed numerical control hydraulic pump provided in the present application breaks through the response lag and positioning error bottleneck of traditional hydraulic valve control through "mechatronic hydraulic coupling control", takes the absolute value servo motor as the movement reference, takes the ball screw as the displacement conversion core, combines the rigid transmission characteristics of the hydraulic closed system, is suitable for high-precision industrial scenes, and can make the linear displacement resolution reach sub-micron positioning of 0.07 um / Step, and can also make the error rate of thrust accuracy less than 0.2%.

[0050] A robot, on the arm of which a closed numerical control hydraulic pump as described above is provided, wherein the sub-pump body 10 is arranged on the large arm 60, the fixing seat 12 at the tail of the sub-pump body 10 is fixed on the large arm 60 near the shoulder bone 80, and the suspended end of the sub-piston 11 is pivoted on the connecting shaft of the large arm and the small arm through the pin shaft 13.

[0051] AsFigure 6 As shown, the robot arm controlled by the double-pump closed numerical control hydraulic pump has two mother pump bodies 20 and a child pump body 10 fixed on the same side of the large arm 60, the mother pump body 20 with a short cylinder body 24 is arranged close to the child pump body 10, the rodless cavity end A of the short cylinder body 24 is communicated with the rodless cavity end C of the child pump body 10 through the hose 30, the rodless cavity end E of the long cylinder body 25 is communicated with the rod cavity end D of the child pump body 10 through the hose 30, thereby forming a closed hydraulic cavity. The PLC controller electric signal controls the servo motor 40 to work, and the servo motor 40 drives the ball screw 22 to rotate through the speed reducer 50, so that the ball screw 22 restricted by the guide rail drives the nut as the mother piston 21 to make linear reciprocating motion; the nut is made into the structure form of the hydraulic cylinder piston, thereby the mother piston 21 can reciprocate in the cylinder body of the mother pump body 20, and the hydraulic oil is extruded or sucked into the cylinder body of the child pump body 10 through the hose, so as to drive the child pump body 10 to drive the small arm 70 to work, thereby adjusting the posture of the robot arm and realizing the anthropomorphic adjustment.

[0052] As shown in Figure 7 If based on the space limitation, the child pump body 10 can be fixed on the large arm 60, and the two mother pump bodies 20 are arranged on the large leg, and the hose 30 is arranged close to the upper body of the robot, so that the child pump body 10 can drive the small arm 70 to adjust the posture.

[0053] Of course, for the structure of the child pump body 10 controlled by the single mother pump body 20, the connection as shown in Figures 5-6 can also be realized, which will not be described in detail here, and the drawing is omitted.

[0054] The numerical control mother pump body 20 indirectly controls the distributed child pump body 10 relying on the flexible pipeline, which can break through the limitation of the traditional hydraulic pump and be applied to the bionic spine of the robot, so that the child pump body 10 is embedded into the mechanical spine joint, and the child pump body 10 is driven to drive the multi-joint to adjust the joint gravity center, so as to adjust the human posture and complete the corresponding action requirements. Thus, the load capacity and bionic motion performance of the humanoid robot are greatly improved, and the modular architecture provides an extensible hardware foundation for future high-dynamic scenarios such as rescue and nursing.

[0055] The closed numerical control hydraulic pump designed by the application comprises a closed single pump body and a double pump body, under the condition of constant oil quantity, the sub-pump body is continuously reciprocated by the parent pump body; the installation position of the sub-pump body is flexible and is not limited by the size of the space range; and the sub-pump body is easy to carry and can be remotely controlled to move; not only the output direction is free, but also the fixed-point stay position is accurate, the energy consumption is small, and it is safe and reliable. The application also provides a robot provided with the closed numerical control hydraulic pump.

[0056] The above detailed description of the embodiments of the application is only the preferred embodiments of the application, and cannot be considered as limiting the scope of the application. Any equivalent changes and improvements made within the scope of the application should still belong to the patent coverage of the application.

Claims

1. A closed-loop numerically controlled hydraulic pump, characterized by, The pump comprises a sub-pump body and at least one mother-pump body, the sub-pump body is connected with the mother-pump body through a hose to form a closed hydraulic chamber, the mother-pump body is driven by a servo motor to drive the sub-pump body to move synchronously.

2. The closed loop numerically controlled hydraulic pump of claim 1, wherein, The servo motor is directly connected with the mother-pump body through a speed reducer, the number of the hoses is two, and the speed reducer is connected with a mother-piston in the mother-pump body through a ball screw.

3. A closed loop numerically controlled hydraulic pump according to claim 1 or 2, characterized in that, The number of the mother-pump bodies is one or two, and the number of the sub-pump bodies is one, the hydraulic chamber in each of the mother-pump bodies and the sub-pump bodies is provided with a rodless chamber end and a rod chamber end.

4. The closed loop numerically controlled hydraulic pump of claim 3, wherein, When the number of the mother-pump bodies is one, the servo motor is connected with the mother-pump body through a speed reducer with a single output shaft, and the diameter of the hydraulic chamber of the sub-pump body is the same as that of the hydraulic chamber of the mother-pump body.

5. The closed loop numerically controlled hydraulic pump of claim 4, wherein, One of the hoses is connected with the rodless chamber end of the hydraulic chamber in the sub-pump body and the mother-pump body respectively, and the other hose is connected with the rod chamber end of the hydraulic chamber in the sub-pump body and the mother-pump body respectively.

6. The closed loop numerically controlled hydraulic pump of claim 3, wherein, When the number of the mother-pump bodies is two, one of the mother-pump bodies has a short cylinder body, and the other of the mother-pump bodies has a long cylinder body, the servo motor is connected with the two mother-pump bodies through a speed reducer with double output shafts.

7. The closed loop numerically controlled hydraulic pump of claim 6 wherein, One of the hoses is connected with the rodless chamber end of the hydraulic chamber in the sub-pump body and the mother-pump body with the short cylinder body respectively, and the other hose is connected with the rod chamber end of the hydraulic chamber in the sub-pump body and the mother-pump body with the long cylinder body respectively.

8. The closed loop numerically controlled hydraulic pump of claim 7, wherein, The diameter of the short cylinder body is greater than that of the long cylinder body.

9. A robot, characterized in that An arm is provided with a closed numerical control hydraulic pump as claimed in any one of claims 1-8, the sub-pump body is arranged on the large arm, the fixed seat at the tail of the sub-pump body is fixed on the side of the large arm close to the shoulder bone, and the suspended end is pivoted on the connecting shaft between the large arm and the small arm through a pin shaft.

10. A robot according to claim 9, characterized in that The mother-pump body and the sub-pump body are arranged on the same side of the large arm or are arranged away from the large arm.

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