CN112901572A

CN112901572A - Pump-controlled double-acting hydraulic actuator

Info

Publication number: CN112901572A
Application number: CN202110243595.3A
Authority: CN
Inventors: 汪立平; 姜鹏; 孙炳玉; 雷政; 靳凯旋; 甘恒谦; 汤安东; 姚蕊; 顾佳鎏; 王勇
Original assignee: National Astronomical Observatories of CAS; Jiangsu Hengli Hydraulic Technology Co Ltd
Current assignee: National Astronomical Observatories of CAS; Jiangsu Hengli Hydraulic Technology Co Ltd
Priority date: 2021-03-05
Filing date: 2021-03-05
Publication date: 2021-06-04

Abstract

The invention relates to the technical field of hydraulic systems, in particular to a pump-controlled double-acting hydraulic actuator which comprises a hydraulic cylinder; the oil tank is independently arranged on one side of the hydraulic cylinder; hydraulic pressure valves, hydraulic pressure valves includes: the device comprises a bidirectional pump, a motor, a balance valve, an electromagnetic valve, a throttle, a first one-way valve, a second one-way valve, a first overflow valve and a first throttle valve. The pump-controlled double-acting hydraulic actuator provided by the invention can be used for carrying out multi-level adjustment on the pressure of a hydraulic system, so that a hydraulic cylinder can realize various action states, oil can be filtered through the arrangement of the first oil filter and the second oil filter, the valve clamping fault caused by dirt in the oil is avoided, a hydraulic loop is remotely and healthily monitored through the arrangement of a plurality of pressure sensors and temperature sensors, and the service life of the actuator is prolonged.

Description

Pump-controlled double-acting hydraulic actuator

Technical Field

The invention relates to the technical field of hydraulic systems, in particular to a pump-controlled double-acting hydraulic actuator.

Background

The hydraulic actuator used in the project of 500 m caliber spherical radio telescope (FAST) is a driving device for actively deforming the reflecting surface of the telescope. The reliability and lifetime of the actuator is critical to the commissioning and observation of the telescope.

The existing chinese patent publication No. CN103629171B discloses a hydraulic actuator with a speed control device, which includes a stepping motor, a bidirectional gear pump, a manual pump and a hydraulic cylinder; the stepping motor is connected with the bidirectional gear pump and controls the output direction and the flow of the bidirectional gear pump; the hydraulic actuator is provided with a speed regulating valve, one end of the speed regulating valve is connected with the first electromagnetic two-way valve, and the other end of the speed regulating valve is connected with one end of the rod cavity of the hydraulic cylinder.

Although the hydraulic actuator in the technical scheme can actuate the hydraulic cylinder, in the using process, multi-level pressure adjustment cannot be performed according to actual using requirements; an oil port of the bidirectional pump is not added with an oil filter, so that pollutants in oil cannot be filtered out in time, and the valve clamping fault is easily caused in the using process; only 1 pressure sensor is installed in the system, and the whole hydraulic circuit cannot be remotely monitored, so that when the hydraulic circuit breaks down, the fault is not conveniently found and eliminated in time, and the use of the actuator is influenced.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: in order to solve the technical problem that a hydraulic actuator in the prior art cannot perform multi-level adjustment on the pressure of a hydraulic system, the invention provides a pump-controlled double-acting hydraulic actuator which can perform multi-level adjustment on the pressure of the hydraulic system, so that a hydraulic cylinder can realize various action states, and the requirement of practical use is conveniently met.

The technical scheme adopted by the invention for solving the technical problems is as follows: a pump controlled double acting hydraulic actuator comprising: the hydraulic cylinder is internally divided into a rodless cavity and a rod cavity;

the oil tank is independently arranged on one side of the hydraulic cylinder;

a hydraulic valve block, the hydraulic valve block comprising: the hydraulic cylinder comprises a bidirectional pump, a motor, a balance valve, an electromagnetic valve, a throttle, a first check valve, a second check valve, a first overflow valve and a first throttle valve, wherein the bidirectional pump is provided with an oil port A and an oil port B, the inlet of the balance valve is communicated with a rod cavity of a hydraulic cylinder through an internal oil path, the outlet of the balance valve is communicated with the oil port B of the bidirectional pump through an internal oil path, the oil port A of the bidirectional pump is communicated with the inlet of the first overflow valve through an internal oil path, the outlet of the first overflow valve is communicated with the inlet of the first throttle valve through an internal oil path, the outlet of the first throttle valve is communicated with a rodless cavity of the hydraulic cylinder through an internal oil path, the inlet of the electromagnetic valve is communicated with the inlet of the balance valve through an internal oil path, the outlet of the electromagnetic valve is communicated with the rodless cavity of the hydraulic cylinder through an internal oil path, the throttle is installed on, the hydraulic pump is characterized in that a first check valve is arranged between the oil port B of the two-way pump and the oil tank, the inlet of the first check valve is communicated with the oil tank through an internal oil way, the outlet of the first check valve is communicated with the oil port B of the two-way pump through an internal oil way, a second check valve is arranged between the oil port A of the two-way pump and the oil tank, the inlet of the second check valve is communicated with the oil tank through an internal oil way, the outlet of the second check valve is communicated with the oil port A of the two-way pump through an internal oil way, the oil tank is communicated with the inlet of the first throttle valve through an internal oil way, and the motor is in transmission.

The pump-controlled double-acting hydraulic actuator can adjust the pressure of a hydraulic system in multiple levels, so that the hydraulic cylinder can realize multiple action states, and the requirement of practical use is conveniently met, and the piston rod of the hydraulic cylinder can realize the following states by the scheme:

1. differential extension, the motor corotation this moment, fluid flows to second check valve department through inside oil circuit, fluid gets into the A hydraulic fluid port of two-way pump along inside oil circuit behind the second check valve, then discharge by the B hydraulic fluid port of two-way pump, flow to solenoid valve department along inside oil circuit behind the balanced valve, the solenoid valve is opened, fluid gets into the rodless intracavity of pneumatic cylinder, under the pressure effect of fluid to the piston, the piston rod stretches out, simultaneously, the fluid that the pneumatic cylinder has the pole chamber also flows to solenoid valve department along inside oil circuit, then flow into the rodless intracavity through inside oil circuit, the pole chamber that has of pneumatic cylinder and rodless chamber at this moment are linked together through inside oil circuit, under the effect of two-way pump, fluid in the oil tank continuously gets into the rodless intracavity of pneumatic cylinder, differential hydraulic circuit has been constituteed, the piston rod slowly stretches.

2. And (4) keeping the position statically, wherein when the motor and the bidirectional pump do not work, the balance valve and the electromagnetic valve are closed, the oil in the rod cavity of the hydraulic cylinder cannot flow out, and the piston rod of the hydraulic cylinder does not act to keep the static state.

3. Passively extending, when the actuator extends under the action of load tension, the electromagnetic valve is in a closed state, oil in a rod cavity of the hydraulic cylinder enters a balance valve through an internal oil way, the motor rotates reversely at the moment, the oil in the oil tank flows to a first check valve through the internal oil way, enters a B oil port of the bidirectional pump through the first check valve, is discharged from an A oil port after being pressurized, when pressure reaches the setting value of a first overflow valve, the balance valve is opened, the oil in a rodless cavity flows out of the balance valve and then enters the B oil port of the bidirectional pump under the action of the load tension, and is discharged through the A oil port, and then enters the rodless cavity of the hydraulic cylinder through the first overflow valve, the flow of the bidirectional pump is controlled by controlling the rotating speed of the motor, and the extension speed of a piston rod is.

4. The initiative is withdrawed, motor corotation this moment, the solenoid valve is in the closed condition, fluid in the oil tank flows to second check valve department through inside oil circuit, the A hydraulic fluid port that gets into the two-way pump along inside oil circuit behind the second check valve, discharge by the B hydraulic fluid port of two-way pump, after opening the balanced valve, fluid gets into the pole intracavity that has of pneumatic cylinder through the balanced valve, under the pressure effect of fluid to the piston, the piston rod retracts, fluid in the no pole intracavity of pneumatic cylinder flows into the oil tank through first choke valve, the flow of two-way pump is controlled through control motor rotational speed, thereby control piston rod withdrawal speed.

5. The servo-actuated hydraulic cylinder extends out, the motor does not work at the moment, the electromagnetic valve is opened, the first throttle valve is opened, the rod cavity and the rodless cavity of the hydraulic cylinder are communicated through the internal oil circuit, the rodless cavity of the hydraulic cylinder is communicated with the oil tank, and the piston can stay at any position under the action of load pull force.

Furthermore, a second throttle valve is arranged on an internal oil path for communicating the rodless cavity of the hydraulic cylinder with the rod cavity, an inlet of the second throttle valve is communicated with an internal oil path at an inlet of the electromagnetic valve, and an outlet of the second throttle valve is communicated with the rodless cavity of the hydraulic cylinder. The second throttle valve is connected with the electromagnetic valve in parallel, and when the electromagnetic valve fails and cannot be opened, the second throttle valve is manually opened, so that circulation of the hydraulic loop is realized.

Further, one end of the inlet of the balance valve is provided with a second overflow valve, the inlet of the second overflow valve is communicated with an internal oil path at the inlet of the balance valve, the outlet of the second overflow valve is communicated with the oil tank through the internal oil path, one end of the oil port B of the bidirectional pump is provided with a third overflow valve, the inlet of the third overflow valve is communicated with the internal oil path at the outlet of the first one-way valve, and the outlet of the third overflow valve is communicated with the oil tank through the internal oil path. The second overflow valve and the third overflow valve can play a safety protection role in the hydraulic circuit, when the load effect is large, the pressure of the hydraulic circuit is too high, and oil in the hydraulic circuit is discharged into an oil tank through the second overflow valve and the third overflow valve, so that the safety protection role is played for the hydraulic circuit.

Further, a first oil filter is arranged on an internal oil path which communicates the oil tank with the first one-way valve. The first oil filter can filter the oil flowing out of the oil tank, filter the dirt in the oil, and prevent the dirt in the oil from entering the bidirectional pump to cause the bidirectional pump to break down.

Further, a second oil filter is installed in an internal oil path that communicates the first overflow valve with the first throttle valve. The second oil filter filters the oil in the hydraulic circuit, filters dirt, bubbles and the like in the oil, and avoids the dirt, the bubbles and the like from causing valve clamping faults.

Furthermore, a first pressure sensor is installed on an internal oil path communicating an oil port B of the two-way pump with the first check valve, a second pressure sensor is arranged on an internal oil path communicating a rod cavity of the hydraulic cylinder with the balance valve, a third pressure sensor for monitoring the internal pressure of the oil tank is installed on one side of the oil tank, and a fourth pressure sensor is installed on an internal oil path communicating the second check valve with the first overflow valve. First pressure sensor can carry out pressure measurement to the fluid that flows from first check valve, second pressure sensor can have the fluid of pole chamber outflow to the pneumatic cylinder to carry out pressure measurement, third pressure sensor can carry out pressure measurement to the oil tank is inside, fourth pressure sensor can detect the oil pressure in second check valve exit, first pressure sensor, second pressure sensor, third pressure sensor and fourth pressure sensor combined action can carry out pressure monitoring to hydraulic circuit, be convenient for in time discover hydraulic circuit's trouble.

Furthermore, a first temperature sensor is arranged on the hydraulic valve group, and a second temperature sensor is arranged on the motor. The first temperature sensor can detect the temperature of the oil flowing out of the oil port B of the bidirectional pump, and the second temperature sensor can detect the temperature of the motor.

Furthermore, a pressurizing leather bag is arranged in the oil tank. The pressurization leather bag can adjust the pressure in the oil tank, and when the oil absorption power of the bidirectional pump is insufficient, the pressure in the oil tank can be increased through the pressurization leather bag, so that oil can conveniently enter the bidirectional pump from the oil tank.

Furthermore, a first pressure measuring connector capable of sampling and detecting the pressure inside the oil tank is arranged on the oil tank.

Furthermore, the oil tank is provided with a first quick plug-in connector which is convenient for replacing oil in the oil tank.

The pump-controlled double-acting hydraulic actuator has the advantages that the piston rod of the hydraulic cylinder can realize various action states, the actual use requirement can be conveniently met, and the applicable scene of the actuator is wider; an oil filter is arranged at an oil port of the bidirectional pump, so that pollutants in oil can be filtered, and the valve clamping fault caused by dirt in the using process is avoided; the setting of a plurality of pressure sensor and temperature sensor can carry out long-range health monitoring to whole hydraulic circuit, when hydraulic circuit broke down, is convenient for in time discover the trouble and get rid of, improves the stability that the actuator used.

Drawings

The invention is further illustrated with reference to the following figures and examples.

Fig. 1 is a hydraulic schematic structure diagram of a pump-controlled double-acting hydraulic actuator according to a preferred embodiment of the present invention.

In the figure: 1. a hydraulic cylinder; 2. an oil tank; 3. a bi-directional pump; 4. a motor; 5. a balancing valve; 6. an electromagnetic valve; 7. a throttle; 8. a first check valve; 9. a second one-way valve; 10. a first overflow valve; 11. a first throttle valve; 12. a second throttle valve; 13. a second overflow valve; 14. a third overflow valve; 15. a first oil filter; 16. a second oil filter; 17. a first pressure sensor; 18. a second pressure sensor; 19. a third pressure sensor; 20. a first temperature sensor; 21. a second temperature sensor; 22. pressurizing the leather bag; 23. a first pressure measuring joint; 24. a first quick plug; 25. a fourth pressure sensor; 26. a second pressure measuring joint; 27. a third pressure measuring joint; 28. a pressure measuring joint IV; 29. a pressure measuring joint V; 30. a pressure measuring joint six; 31. a pressure measuring joint seven; 32. a second quick connector; 33. and a third quick connector.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified. In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1, a pump controlled double acting hydraulic actuator according to a preferred embodiment of the present invention comprises: the hydraulic cylinder 1 is internally divided into a rodless cavity and a rod cavity; the oil tank 2 is independently arranged on one side of the hydraulic cylinder 1, and a pressurizing leather bag 22 is arranged in the oil tank 2. Pressurization leather bag 22 can be adjusted the pressure in the oil tank 2, and when the oil absorption power of two-way pump 3 was not enough, can be to increasing the pressure in the oil tank 2 through pressurization leather bag 22, during fluid entered into two-way pump 3 from oil tank 2, be provided with on the oil tank 2 and can take a sample and the pressure measurement that detects the pressure of 2 inside oil tanks connects 23, is provided with on the oil tank 2 and is convenient for carry out the first 24 of the quick grafting of changing to the fluid in the oil tank 2.

Hydraulic pressure valves, hydraulic pressure valves includes: the two-way pump 3, the motor 4, the balance valve 5, the electromagnetic valve 6, the throttle 7, the first check valve 8, the second check valve 9, the first overflow valve 10 and the first throttle valve 11, the two-way pump 3 is provided with an oil port A and an oil port B, an inlet of the balance valve 5 is communicated with a rod cavity of the hydraulic cylinder 1 through an internal oil way, an outlet of the balance valve 5 is communicated with the oil port B of the two-way pump 3 through the internal oil way, one end of an inlet of the balance valve 5 is provided with the second overflow valve 13, an inlet of the second overflow valve 13 is communicated with the internal oil way at the inlet of the balance valve 5, an outlet of the second overflow valve 13 is communicated with the oil tank 2 through the internal oil,

an oil port A of the bidirectional pump 3 is communicated with an inlet of a first overflow valve 10 through an internal oil path, an outlet of the first overflow valve 10 is communicated with an inlet of a first throttle valve 11 through the internal oil path, an outlet of the first throttle valve 11 is communicated with a rodless cavity of the hydraulic cylinder 1 through the internal oil path, and a second oil filter 16 is installed on the internal oil path communicating the first overflow valve 10 with the first throttle valve 11. The second oil filter 16 filters oil in the hydraulic circuit, and filters dirt, bubbles and the like in the oil, so that the valve clamping fault caused by the dirt, the bubbles and the like is avoided.

The inlet of the electromagnetic valve 6 is communicated with the inlet of the balance valve 5 through an internal oil path, the outlet of the electromagnetic valve 6 is communicated with the rodless cavity of the hydraulic cylinder 1 through an internal oil path, the throttle 7 is installed on the internal oil path communicating the electromagnetic valve 6 with the rodless cavity of the hydraulic cylinder 1, the rodless cavity of the hydraulic cylinder 1 and the internal oil path having the rod cavity are provided with a second throttle valve 12, the inlet of the second throttle valve 12 is communicated with the internal oil path at the inlet of the electromagnetic valve 6, and the outlet of the second throttle valve 12 is communicated with the rodless cavity of the hydraulic cylinder 1. The second throttle valve 12 is connected in parallel with the electromagnetic valve 6, and when the electromagnetic valve 6 fails and cannot be opened, the second throttle valve 12 is manually opened to realize the circulation of the hydraulic circuit.

A first check valve 8 is arranged between an oil port B of the two-way pump 3 and the oil tank 2, an inlet of the first check valve 8 is communicated with the oil tank 2 through an internal oil way, an outlet of the first check valve 8 is communicated with the oil port B of the two-way pump 3 through an internal oil way, one end of the oil port B of the two-way pump 3 is provided with a third overflow valve 14, an inlet of the third overflow valve 14 is communicated with the internal oil way at an outlet of the first check valve 8, and an outlet of the third overflow valve 14 is communicated with the oil tank 2 through an internal oil way.

A first oil filter 15 is attached to an internal oil path that communicates the oil tank 2 with the first check valve 8. The first oil filter 15 can filter the oil flowing out of the oil tank 2, so that the dirt in the oil can be filtered, and the two-way pump 3 is prevented from being broken down due to the fact that the dirt in the oil enters the two-way pump 3.

A second check valve 9 is arranged between the oil port A of the two-way pump 3 and the oil tank 2, the inlet of the second check valve 9 is communicated with the oil tank 2 through an internal oil path, the outlet of the second check valve 9 is communicated with the oil port A of the two-way pump 3 through an internal oil path, the oil tank 2 is communicated with the inlet of the first throttle valve 11 through an internal oil path, and the motor 4 is in transmission connection with the two-way pump 3.

A first pressure sensor 17 is installed on an internal oil path for communicating an oil port of the bidirectional pump 3B with the first check valve 8, a second pressure sensor 18 is arranged on an internal oil path for communicating a rod cavity of the hydraulic cylinder 1 with the balance valve 5, a third pressure sensor 19 for monitoring the internal pressure of the oil tank 2 is installed on one side of the oil tank 2, and a fourth pressure sensor 25 is installed on an internal oil path for communicating the second check valve 9 with the first overflow valve 10.

First pressure sensor 17 can carry out pressure measurement to the fluid that flows out from first check valve 8, second pressure sensor 18 can have the pole chamber to the pneumatic cylinder 1 to flow fluid and carry out pressure measurement, third pressure sensor 19 can carry out pressure measurement to 2 insides of oil tank, fourth pressure sensor 25 can detect the oil pressure in second check valve 9 exit, first pressure sensor 17, second pressure sensor 18, third pressure sensor 19 and fourth pressure sensor 25 combined action can carry out pressure monitoring to hydraulic circuit, be convenient for in time discover hydraulic circuit's trouble.

The hydraulic valve group is provided with a first temperature sensor 20, and the motor 4 is provided with a second temperature sensor 21. First temperature sensor 20 can detect the temperature of hydraulic pressure valves, and second temperature sensor 21 can detect the temperature of motor 4, can in time discover the condition that hydraulic pressure valves and motor 4 temperature rise, is convenient for carry out health monitoring to the system.

The hydraulic valve group also comprises a second pressure measuring joint 26, a third pressure measuring joint 27, a fourth pressure measuring joint 28, a fifth pressure measuring joint 29, a sixth pressure measuring joint 30, a seventh pressure measuring joint 31, a second quick-connect joint 32 and a third quick-connect joint 33, wherein the second pressure measuring joint 26 is arranged on an internal oil path communicated with the first oil filter 15 and the first check valve 8, the third pressure measuring joint 27 is arranged on an internal oil path communicated with the oil port B of the first check valve 8 and the two-way pump 3, the fourth pressure measuring joint 28 is arranged on an internal oil path communicated with the second check valve 9 and the first overflow valve 10, the fifth pressure measuring joint 29 is arranged on an internal oil path communicated with the balance valve 5 and the rod cavity of the hydraulic cylinder 1, the sixth pressure measuring joint 30 is arranged on an internal oil path communicated with the rod cavity of the hydraulic cylinder 1 and the throttle valve, the seventh pressure measuring joint 31 is arranged on an internal oil path communicated with the second oil filter 16 and the first overflow valve 10, the second quick-connect joint 32 is arranged, and a third quick-connection-plug connector 33 is arranged on an internal oil path for communicating the rod cavity of the hydraulic cylinder 1 with the balance valve 5.

The working principle is as follows: referring to fig. 1, the pump-controlled double-acting hydraulic actuator of the present invention can make the piston rod of the hydraulic cylinder 1 achieve the following states:

1. differential extension, at the moment, the motor 4 rotates forwards, the first throttle valve 11 is closed, the balance valve 5 is opened, oil in the oil tank 2 flows to the second one-way valve 9 through an internal oil path, the oil enters the oil port A of the two-way pump 3 along the internal oil path after passing through the second one-way valve 9 and then is discharged from the oil port B of the two-way pump 3, the oil flows to the electromagnetic valve 6 and the second throttle valve 12 along the internal oil path after passing through the balance valve 5, the electromagnetic valve 6 or the second throttle valve 12 is opened, the oil enters the rodless cavity of the hydraulic cylinder 1, under the pressure action of the oil on a piston, a piston rod extends out, meanwhile, the oil in the rod cavity of the hydraulic cylinder 1 also flows to the electromagnetic valve 6 and the second throttle valve 12 along the internal oil path and then flows into the rodless cavity through the internal oil path, at the moment, the rod cavity and the rodless cavity of the hydraulic, the oil in the oil tank 2 continuously enters the rodless cavity of the hydraulic cylinder 1 to form a differential hydraulic circuit, and the piston rod slowly extends out.

2. The static position is protected, when motor 4 and bidirectional pump 3 were out of work, closed balanced valve 5, solenoid valve 6, second choke valve 12, and pneumatic cylinder 1 had the unable outflow of fluid in the rod intracavity, and pneumatic cylinder 1 piston rod does not have the action, keeps quiescent condition, if load pressure is too big, and pneumatic cylinder 1 has the too high oil pressure of rod intracavity, and accessible second overflow valve 13 carries out the oil extraction to the fluid that has the rod intracavity, and second overflow valve 13 plays the safety protection effect.

3. Passively extending, when the actuator extends under the action of load tension, the electromagnetic valve 6 and the second throttle valve 12 are in a closed state, the first throttle valve 11 is opened, oil in a rod cavity of the hydraulic cylinder 1 enters the balance valve 5 through an internal oil way, at the moment, the motor 4 rotates reversely, the oil in the oil tank 2 flows to a first oil filter 15 through the internal oil way, the flowing oil is filtered through the first oil filter 15, then flows to a first one-way valve 8, enters an oil port B of the bidirectional pump 3 after passing through the first one-way valve 8, is discharged through an oil port A after being pressurized, when the pressure reaches the set value of a first overflow valve 10, the balance valve 5 is opened, the oil in the rodless cavity flows out of the balance valve 5 under the action of load tension, enters the oil port B of the bidirectional pump 3, then is discharged through the oil port A, and then enters the rodless cavity of the hydraulic cylinder 1 through the first overflow valve 10, the flow rate of the bidirectional pump 3 is controlled by controlling the rotating speed of the motor 4, so that the extending speed of the piston rod is controlled.

4. Active retraction, at the moment, the motor 4 rotates positively, the electromagnetic valve 6 and the second throttle valve 12 are in a closed state, oil in the oil tank 2 flows to the first oil filter 15 through an internal oil way, the flowing oil is filtered through the first oil filter 15, then the oil flows to the second check valve 9 through the internal oil way, the oil enters the oil port A of the two-way pump 3 along the internal oil way after passing through the second check valve 9 and is discharged from the oil port B of the two-way pump 3, after the balance valve 5 is opened, the oil enters the rod cavity of the hydraulic cylinder 1 through the balance valve 5, under the pressure action of the oil on the piston, the piston rod retracts, the oil in the rodless cavity of the hydraulic cylinder 1 flows into the oil tank 2 through the first throttle valve 11, the flow of the two-way pump 3 is controlled by controlling the rotating speed of the motor 4, and.

5. The servo-actuated extension is realized, at the moment, the motor 4 does not work, the electromagnetic valve 6 is opened, the first throttle valve 11 is opened, the rod cavity and the rodless cavity of the hydraulic cylinder 1 are communicated through an internal oil circuit, the rodless cavity of the hydraulic cylinder 1 is communicated with the oil tank 2, and the piston can stay at any position under the action of load pull force. In an emergency, if the electromagnetic valve 6 fails to open, the second throttle valve 12 can be manually opened to realize circulation of the circuit, so that the hydraulic circuit is protected safely.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Claims

1. A pump controlled double acting hydraulic actuator characterized by: comprises that

The hydraulic cylinder (1) is internally divided into a rodless cavity and a rod cavity;

the oil tank (2) is independently arranged on one side of the hydraulic cylinder (1);

a hydraulic valve block, the hydraulic valve block comprising: the hydraulic cylinder comprises a bidirectional pump (3), a motor (4), a balance valve (5), an electromagnetic valve (6), a throttle (7), a first check valve (8), a second check valve (9), a first overflow valve (10) and a first throttle valve (11), wherein the bidirectional pump (3) is provided with an oil port A and an oil port B, the inlet of the balance valve (5) is communicated with a rod cavity of the hydraulic cylinder (1) through an internal oil way, the outlet of the balance valve (5) is communicated with the oil port B of the bidirectional pump (3) through an internal oil way, the oil port A of the bidirectional pump (3) is communicated with the inlet of the first overflow valve (10) through an internal oil way, the outlet of the first overflow valve (10) is communicated with the inlet of the first throttle valve (11) through an internal oil way, the outlet of the first throttle valve (11) is communicated with a rodless cavity of the hydraulic cylinder (1) through an internal oil way, the inlet of the electromagnetic valve (6) is communicated with the inlet of the balance valve (5) through an internal oil way, the outlet of the electromagnetic valve (6) is communicated with a rodless cavity of the hydraulic cylinder (1) through an internal oil way, the throttle (7) is installed on the internal oil way which communicates the electromagnetic valve (6) with the rodless cavity of the hydraulic cylinder (1), a first one-way valve (8) is arranged between an oil port B of the two-way pump (3) and the oil tank (2), the inlet of the first one-way valve (8) is communicated with the oil tank (2) through an internal oil way, the outlet of the first one-way valve (8) is communicated with the oil port B of the two-way pump (3) through an internal oil way, a second one-way valve (9) is arranged between the oil port A of the two-way pump (3) and the oil tank (2), the inlet of the second one-way valve (9) is communicated with the oil tank (2) through an internal oil way, and the outlet of the second one-way valve (9, the oil tank (2) is communicated with an inlet of the first throttling valve (11) through an internal oil path, and the motor (4) is in transmission connection with the bidirectional pump (3).

2. A pump controlled double acting hydraulic actuator as defined in claim 1, wherein: and a second throttle valve (12) is arranged on an internal oil path for communicating the rodless cavity and the rod cavity of the hydraulic cylinder (1), the inlet of the second throttle valve (12) is communicated with the internal oil path at the inlet of the electromagnetic valve (6), and the outlet of the second throttle valve (12) is communicated with the rodless cavity of the hydraulic cylinder (1).

3. A pump controlled double acting hydraulic actuator as defined in claim 1, wherein: the oil-saving control system is characterized in that a second overflow valve (13) is arranged at one end of an inlet of the balance valve (5), the inlet of the second overflow valve (13) is communicated with an internal oil way at the inlet of the balance valve (5), an outlet of the second overflow valve (13) is communicated with the oil tank (2) through the internal oil way, a third overflow valve (14) is arranged at one end of an oil port B of the bidirectional pump (3), the inlet of the third overflow valve (14) is communicated with the internal oil way at the outlet of the first check valve (8), and the outlet of the third overflow valve (14) is communicated with the oil tank (2) through the internal oil way.

4. A pump controlled double acting hydraulic actuator as defined in claim 1, wherein: a first oil filter (15) is arranged on an internal oil path which communicates the oil tank (2) and the first one-way valve (8).

5. A pump controlled double acting hydraulic actuator as defined in claim 4, wherein: a second oil filter (16) is installed on an internal oil path which communicates the first overflow valve (10) and the first throttle valve (11).

6. A pump controlled double acting hydraulic actuator as defined in claim 1, wherein: the hydraulic cylinder is characterized in that a first pressure sensor (17) is arranged on an internal oil path communicated with an oil port B of the bidirectional pump (3) and the first check valve (8), the hydraulic cylinder (1) is communicated with a rod cavity and a balance valve (5), a second pressure sensor (18) is arranged on the internal oil path, a third pressure sensor (19) for monitoring the internal pressure of the oil tank (2) is arranged on one side of the oil tank (2), and a fourth pressure sensor (25) is arranged on the internal oil path communicated with the second check valve (9) and the first overflow valve (10).

7. A pump controlled double acting hydraulic actuator as defined in claim 6, wherein: be equipped with first temperature sensor (20) on the hydraulic valve group, be provided with second temperature sensor (21) on motor (4).

8. A pump controlled double acting hydraulic actuator as defined in claim 1, wherein: a pressurizing leather bag (22) is arranged in the oil tank (2).

9. A pump controlled double acting hydraulic actuator as defined in claim 1, wherein: the oil tank (2) is provided with a pressure measuring connector I (23) capable of sampling and detecting the pressure in the oil tank (2).

10. A pump controlled double acting hydraulic actuator as defined in claim 1, wherein: the oil tank (2) is provided with a first quick plug (24) which is convenient for replacing oil in the oil tank (2).