Energy-saving hydraulic pressure holding device and its control method

Abstract

The present invention provides an energy-saving hydraulic pressure holding device and its control method. The device includes a hydraulic cylinder; a first outlet of a proportional valve is connected to a rodless cavity of the hydraulic cylinder to form a first oil circuit, and a second outlet of the proportional valve is connected to a rod-end cavity of the hydraulic cylinder to form a second oil circuit; a first check valve is connected to a first electromagnetic directional valve to form a third oil circuit; a second check valve is connected to a second electromagnetic directional valve to form a fourth oil circuit; a controller is electrically connected to the first electromagnetic directional valve and the second electromagnetic directional valve respectively to control one of the first electromagnetic directional valve and the second electromagnetic directional valve to open and the other to close, so that one of the third oil circuit and the first oil circuit and one of the fourth oil circuit and the second oil circuit are connected and the other is closed. The hydraulic pressure holding device according to the embodiment of the present invention realizes bidirectional flow regeneration control of the hydraulic cylinder, improving the energy-saving effect of the hydraulic pressure holding circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic energy saving, and particularly to an energy-saving hydraulic pressure maintaining device and its control method. Background Art

[0002] Hydraulic energy saving is mainly achieved by hydraulic differential circuits and regenerative circuits, which are collectively referred to as "regenerative circuits" herein. Hydraulic regenerative circuits have been widely used in mechanical and industrial fields, etc. Conventional regenerative circuits utilize the energy of the rodless chamber to increase the extending speed of the rodless chamber of the hydraulic cylinder, or utilize the energy in the rodless chamber to increase the extending speed of the rod chamber of the hydraulic cylinder, while the existing hydraulic energy-saving control means have poor energy-saving and pressure-maintaining effects. Summary of the Invention

[0003] In view of this, the present invention provides an energy-saving hydraulic pressure maintaining device, and the hydraulic pressure maintaining circuit realizes two-way energy saving and improves the energy-saving effect.

[0004] To solve the above technical problems, the present invention adopts the following technical solutions:

[0005] In a first aspect, an energy-saving hydraulic pressure maintaining device according to an embodiment of the present invention includes:

[0006] A hydraulic cylinder;

[0007] A proportional valve, a first outlet of the proportional valve is connected to the rodless chamber of the hydraulic cylinder to form a first oil circuit, and a second outlet of the proportional valve is connected to the rod chamber of the hydraulic cylinder to form a second oil circuit;

[0008] A first one-way valve and a first electromagnetic directional valve, the first one-way valve is connected to the first electromagnetic directional valve to form a third oil circuit, one end of the first electromagnetic directional valve is connected to the rodless chamber so that the first oil circuit can be unidirectionally conducted to the third oil circuit, and one end of the first one-way valve is connected to the second oil circuit;

[0009] A second one-way valve and a second electromagnetic directional valve, the second one-way valve is connected to the second electromagnetic directional valve to form a fourth oil circuit, one end of the second electromagnetic directional valve is connected to the rod chamber so that the second oil circuit and the fourth oil circuit are unidirectionally conducted, and one end of the second one-way valve is connected to the first oil circuit;

[0010] A controller, electrically connected to the first electromagnetic directional valve and the second electromagnetic directional valve respectively to control one of the first electromagnetic directional valve and the second electromagnetic directional valve to open and the other to close so that one of the third oil circuit and the first oil circuit and one of the fourth oil circuit and the second oil circuit are connected and the other is closed.

[0011] Further, it further includes:

[0012] The first balance valve and the second balance valve, the first balance valve and the second balance valve are respectively connected to the first oil circuit and the second oil circuit, and the first balance valve is located between the connection of the third oil circuit and the first oil circuit and the proportional valve, and the second balance valve is located between the connection of the fourth oil circuit and the second oil circuit and the proportional valve.

[0013] Further, it further includes:

[0014] The first control oil circuit, one end of which is connected to the first one-way valve, the other end of which is connected to the first oil circuit, and the connection of the first control oil circuit and the first oil circuit is located between the first balance valve and the proportional valve;

[0015] The second control oil circuit, one end of which is connected to the second one-way valve, the other end of which is connected to the second oil circuit, and the connection of the second control oil circuit and the second oil circuit is located between the second balance valve and the proportional valve.

[0016] Further, the first electromagnetic directional valve is located between the first one-way valve and the first oil circuit.

[0017] Further, the second electromagnetic directional valve is located between the second one-way valve and the second oil circuit.

[0018] Further, it further includes:

[0019] A sensor, which is installed in the hydraulic cylinder, the sensor is connected to the controller, and the sensor is used to detect the displacement of the hydraulic cylinder in real time.

[0020] In a second aspect, an embodiment of the present invention further provides a control method for an energy-saving hydraulic pressure holding device, which is applied to the energy-saving hydraulic pressure holding device, and includes:

[0021] When the hydraulic cylinder extends, the pressure oil flows from the first outlet of the proportional valve through the first oil circuit into the rodless cavity, and the controller sends an opening instruction to the second electromagnetic directional valve, the second electromagnetic directional valve opens, the pressure oil flows into the second one-way valve, the second one-way valve conducts, and the pressure oil in the rod chamber enters the rodless cavity through the second oil circuit, the fourth oil circuit, and the first oil circuit;

[0022] When the hydraulic cylinder retracts, the pressure oil flows from the second outlet of the proportional valve through the second oil circuit into the rod chamber, and the controller sends an opening instruction to the first electromagnetic directional valve, the first electromagnetic directional valve opens, the pressure oil flows into the first one-way valve, the first one-way valve conducts, and the pressure oil in the rodless cavity enters the rod chamber through the first oil circuit, the third oil circuit, and the second oil circuit.

[0023] Further, it includes:

[0024] When the load changes greatly and the hydraulic cylinder extends, the controller sends an instruction to the proportional valve, and the pressure oil flows from the first outlet of the proportional valve through the first oil passage into the rodless cavity, and the second electromagnetic directional valve opens.

[0025] When the pressure of the pressure oil in the second oil passage is less than the opening pressure of the second balance valve, the pressure oil in the second oil passage flows into the second one-way valve, the second one-way valve conducts, and the pressure oil in the rod cavity flows through the second oil passage, the fourth oil passage, and the first oil passage into the rodless cavity.

[0026] When the pressure of the pressure oil in the second oil passage is greater than or equal to the opening pressure of the second balance valve, the pressure oil flowing out of the rod cavity flows through the second balance valve and then into the oil tank.

[0027] Furthermore, it includes:

[0028] When the load changes greatly and the hydraulic cylinder retracts, the controller sends an instruction to the proportional valve, and the pressure oil flows from the second outlet of the proportional valve through the second oil passage into the rod cavity, and the first electromagnetic directional valve opens.

[0029] When the pressure of the pressure oil in the first oil passage is less than the opening pressure of the first balance valve, the controller sends an opening instruction to the first electromagnetic directional valve, the pressure oil in the first oil passage flows into the first one-way valve, the first one-way valve conducts, and the pressure oil in the rodless cavity flows through the first oil passage, the third oil passage, and the second oil passage into the rod cavity.

[0030] When the pressure of the pressure oil in the first oil passage is greater than or equal to the opening pressure of the first balance valve, the pressure oil flowing out of the rodless cavity flows through the first balance valve and then into the oil tank.

[0031] Furthermore, when the pressure of the pressure oil in the first oil passage is greater than the opening pressure of the first balance valve, the pressure oil flows through the second control oil passage into the second one-way valve to close the second one-way valve.

[0032] When the pressure of the pressure oil in the second oil passage is greater than the opening pressure of the second balance valve, the pressure oil flows through the first control oil passage into the first one-way valve to close the first one-way valve.

[0033] At least one of the above technical solutions of the present invention has the following beneficial effects:

[0034] The energy-saving hydraulic pressure maintaining device and its control method disclosed by the present invention. The hydraulic pressure maintaining device is connected with a third oil circuit and a fourth oil circuit between a first oil circuit and a second oil circuit, and realizes the bidirectional flow regeneration control of the hydraulic cylinder by using a first one-way valve, a first electromagnetic directional valve, a second one-way valve and a second electromagnetic directional valve, so as to improve the energy-saving effect of the hydraulic pressure maintaining circuit. In addition, the automatic switching between the regeneration circuit and the non-regeneration circuit can be realized by controlling the first balance valve and the second balance valve, so as to improve the load stability, and the hydraulic pressure maintaining circuit can adjust the speed, stop accurately and maintain the pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 FIG. is a schematic diagram of the overall structure of the energy-saving hydraulic pressure maintaining device provided by an embodiment of the present invention;

[0036] Figure 2 FIG. is a schematic diagram of the flow direction of the pressure oil when the hydraulic cylinder extends in an embodiment of the control method of the energy-saving hydraulic pressure maintaining device provided by an embodiment of the present invention;

[0037] Figure 3 FIG. is a schematic diagram of the flow direction of the pressure oil when the hydraulic cylinder retracts in an embodiment of the control method of the energy-saving hydraulic pressure maintaining device provided by an embodiment of the present invention;

[0038] Figure 4 FIG. is a schematic diagram of the flow direction of the pressure oil when the hydraulic cylinder extends in another embodiment of the control method of the energy-saving hydraulic pressure maintaining device provided by an embodiment of the present invention;

[0039] Figure 5 FIG. is a schematic diagram of the flow direction of the pressure oil when the hydraulic cylinder retracts in another embodiment of the control method of the energy-saving hydraulic pressure maintaining device provided by an embodiment of the present invention.

[0040] REFERENCE SIGNS:

[0041] 10. Controller; 20. Hydraulic cylinder; 210. Rod chamber; 220. Rodless chamber; 30. Proportional valve; 40. First one-way valve; 50. First electromagnetic directional valve; 60. Second electromagnetic directional valve; 70. Second one-way valve; 80. First balance valve; 90. Second balance valve; a. First oil circuit; b. Second oil circuit; c. Third oil circuit; d. Fourth oil circuit; e. First control oil circuit; f. Second control oil circuit; g. Third control oil circuit; h. Fourth control oil circuit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.

[0043] An energy-saving hydraulic pressure maintaining device is provided in an embodiment of the present invention. The device uses a controller 10 to separately control a first electromagnetic directional valve 50 and a second electromagnetic directional valve 60 on a third oil circuit c and a fourth oil circuit d, so that when a hydraulic cylinder 20 extends or retracts, a first one-way valve 40 or a second one-way valve 70 conducts the third oil circuit c or the fourth oil circuit d, realizing bidirectional flow regeneration control of the hydraulic cylinder 20 and improving the energy-saving effect of the device.

[0044] First, a specific description will be given below of an energy-saving hydraulic pressure maintaining device according to an embodiment of the present invention with reference to the accompanying drawings.

[0045] Specifically, as Figure 1 shown, an energy-saving hydraulic pressure maintaining device provided in an embodiment of the present invention includes a hydraulic cylinder 20, a proportional valve 30, a first one-way valve 40, a first electromagnetic directional valve 50, a second one-way valve 70, a second electromagnetic directional valve 60, and a controller 10.

[0046] Among them, a first outlet of the proportional valve 30 is connected to a rodless cavity 220 of the hydraulic cylinder 20 to form a first oil circuit a, and a second outlet of the proportional valve 30 is connected to a rod cavity 210 of the hydraulic cylinder 20 to form a second oil circuit b.

[0047] The first one-way valve 40 is connected to the first electromagnetic directional valve 50 to form a third oil circuit c. One end of the first electromagnetic directional valve 50 is connected to the rodless cavity 220 so that the first oil circuit a can conduct unidirectionally to the third oil circuit c. One end of the first one-way valve 40 is connected to the second oil circuit b.

[0048] The second one-way valve 70 is connected to the second electromagnetic directional valve 60 to form a fourth oil circuit d. One end of the second electromagnetic directional valve 60 is connected to the rod cavity 210 so that the second oil circuit b and the fourth oil circuit d conduct unidirectionally. One end of the second one-way valve 70 is connected to the first oil circuit a.

[0049] The controller 10 is electrically connected to the first electromagnetic directional valve 50 and the second electromagnetic directional valve 60 respectively to control one of the first electromagnetic directional valve 50 and the second electromagnetic directional valve 60 to open and the other to close, so that one of the third oil circuit c and the first oil circuit a and the other of the fourth oil circuit d and the second oil circuit b are connected and the other is closed.

[0050] That is, the controller 10 controls the proportional valve 30 to deliver pressure oil from its first outlet or second outlet to the rodless chamber 220 or the rod chamber 210 respectively, so as to realize the rapid extension or retraction of the hydraulic cylinder 20. The first outlet is Figure 1 the A outlet of the proportional valve 30 in Figure 1 and the second outlet is the B outlet of the proportional valve 30 in

[0051] The controller 10 realizes that when the hydraulic cylinder 20 extends, the hydraulic oil in the rod chamber 210 can enter the rodless chamber 220 from the second oil circuit b through the fourth oil circuit d and the first oil circuit a, and when the hydraulic cylinder 20 retracts, the hydraulic oil in the rodless chamber 220 can enter the rod chamber 210 from the first oil circuit a through the third oil circuit c and the second oil circuit b by respectively controlling the first electromagnetic directional valve 50 and the second electromagnetic directional valve 60, so as to realize the two-way flow regeneration control of the hydraulic cylinder 20, improve the energy-saving effect, and enable the hydraulic cylinder 20 to accurately stop at the specified position, improving the accuracy of the hydraulic cylinder 20.

[0052] In an embodiment, as Figure 1 shown, the hydraulic pressure holding device further includes a first balance valve 80 and a second balance valve 90. The first balance valve 80 and the second balance valve 90 are respectively connected to the first oil circuit a and the second oil circuit b, and the first balance valve 80 is located between the connection of the third oil circuit c and the first oil circuit a and the proportional valve 30, and the second balance valve 90 is located between the connection of the fourth oil circuit d and the second oil circuit b and the proportional valve 30.

[0053] When the hydraulic cylinder 20 extends, the pressure oil enters the rodless chamber 220 from the first outlet of the proportional valve 30 through the first oil circuit a. When the pressure generated by the pressure oil is less than the opening pressure set by the second balance valve 90, the second balance valve 90 cannot be opened, so the pressure oil cannot pass through the second balance valve 90. When the pressure generated by the pressure oil is greater than or equal to the opening pressure set by the second balance valve 90, the second balance valve 90 opens, and the pressure oil passes through the second balance valve 90 and flows into the oil cylinder. The first balance valve 80 has the same principle as the second balance valve 90, and the description will not be repeated here.

[0054] When the first balance valve 80 or the second balance valve 90 is not opened, when the hydraulic cylinder 20 extends or retracts, the hydraulic oil forms a regeneration circuit through the fourth oil circuit d or the third oil circuit c, improving the energy-saving effect of the hydraulic cylinder 20.

[0055] After the first balance valve 80 or the second balance valve 90 is opened, when the hydraulic cylinder 20 extends or retracts, the hydraulic oil flows through the first balance valve 80 or the second balance valve 90 and flows into the oil cylinder, and the regeneration circuit is automatically switched to a non-regeneration circuit, and the hydraulic cylinder 20 realizes high-pressure extension or retraction, improving the safety performance and stability of the hydraulic cylinder 20.

[0056] In one embodiment, the hydraulic pressure maintaining device further includes a first control oil circuit e and a second control oil circuit f.

[0057] One end of the first control oil circuit e is connected to the first one-way valve 40, and the other end thereof is connected to the first oil circuit a. The connection between the first control oil circuit e and the first oil circuit a is located between the first balance valve 80 and the proportional valve 30.

[0058] One end of the second control oil circuit f is connected to the second one-way valve 70, and the other end thereof is connected to the second oil circuit b. The connection between the second control oil circuit f and the second oil circuit b is located between the second balance valve 90 and the proportional valve 30.

[0059] The first one-way valve 40 and the first control oil circuit e form a first hydraulic control one-way valve, and the second one-way valve 70 and the second control oil circuit f form a second hydraulic control one-way valve.

[0060] That is to say, when the hydraulic cylinder 20 extends, the pressure oil enters the rodless cavity 220 from the first outlet of the proportional valve 30 through the first oil circuit a. When the pressure generated by the pressure oil is less than the opening pressure set by the second balance valve 90, the second balance valve 90 cannot be opened. At the same time, the pressure oil on the first oil circuit a flows into the first one-way valve 40 to close the first one-way valve 40, realizing flow regeneration. When the hydraulic cylinder 20 retracts, the pressure oil enters the rod cavity 210 from the second outlet of the proportional valve 30 through the second oil circuit b. When the pressure generated by the pressure oil is less than the opening pressure set by the first balance valve 80, the first balance valve 80 cannot be opened. At the same time, the pressure oil on the second oil circuit b flows into the second one-way valve 70 to close the second one-way valve 70, realizing flow regeneration.

[0061] In one embodiment, the first electromagnetic directional valve 50 is located between the first one-way valve 40 and the first oil circuit a.

[0062] The second electromagnetic directional valve 60 is located between the second one-way valve 70 and the second oil circuit b.

[0063] By controlling the first electromagnetic directional valve 50 and the second electromagnetic directional valve 60 through the controller 10, and controlling the closing of the first one-way valve 40 and the second one-way valve 70 through the first control oil circuit e and the second control oil circuit f, the response speed of the device is improved and the power consumption is reduced.

[0064] In one embodiment, the hydraulic pressure maintaining device further includes a sensor. The sensor is preferably a magnetostrictive linear analog sensor, which is used to detect the displacement of the hydraulic cylinder 20 in real time and feed back the detected signal to the controller 10. According to different application environments, the sensor can be installed inside the hydraulic cylinder 20 or outside the hydraulic cylinder 20. The embodiment of the present invention does not make a limitation. The cooperation between the sensor and the controller 10 enables the hydraulic cylinder 20 to accurately stop at a specified position and maintain pressure at any position, improving the accuracy of the device.

[0065] Inside the controller 10, there is a filtering circuit which can filter the collected signals. At the same time, the controller 10 analyzes and calculates according to the required motion command signal and feedback signal, and then obtains the control signal of the device and sends it to the proportional valve 30 respectively. Similarly, the proportional valve 30 can adjust the strength of the electric signal of the proportional valve 30 according to the motion requirements of the hydraulic cylinder 20 and the sensor feedback, and reflect the motion result on the displacement change of the hydraulic cylinder 20. In this way, a control motion cycle is completed. After multiple set control cycles, the closed-loop system completes the specified motion.

[0066] The hydraulic pressure holding device provided by the embodiment of the present invention can realize the automatic switching between the regeneration circuit and the non-regeneration circuit, can make the hydraulic cylinder 20 stop at the preset position, and the hydraulic cylinder 20 can realize multiple automatic switches between the regeneration circuit and the non-regeneration circuit during a stroke, and the switching is stable; and when the device does not work, it can stop at different times and different positions and keep the position unchanged for a long time, improving the reliability and stability of the device.

[0067] In one embodiment, as Figure 1 shown, the hydraulic pressure holding device includes a third control oil circuit g and a fourth control oil circuit h, and the third control oil circuit g and the fourth control oil circuit h are respectively used to control the opening pressure and the opening amount of the first balance valve 80 and the second balance valve 90.

[0068] The embodiment of the present invention also provides a control method for an energy-saving hydraulic pressure holding device, which is applied to the energy-saving hydraulic pressure holding device. The control method includes:

[0069] As Figure 2 shown, when the hydraulic cylinder 20 extends, the pressure oil flows from the first outlet of the proportional valve 30 into the rodless cavity 220 through the first oil circuit a, and the controller 10 sends an opening instruction to the second electromagnetic directional valve 60. The second electromagnetic directional valve 60 opens, and the pressure oil flows into the second one-way valve 70. The second one-way valve 70 is conducted, and the pressure oil in the rod cavity 210 enters the rodless cavity 220 through the second oil circuit b, the fourth oil circuit d, and the first oil circuit a.

[0070] As Figure 3 shown, when the hydraulic cylinder 20 retracts, the pressure oil flows from the second outlet of the proportional valve 30 into the rod cavity 210 through the second oil circuit b, and the controller 10 sends an opening instruction to the first electromagnetic directional valve 50. The first electromagnetic directional valve 50 opens, and the pressure oil flows into the first one-way valve 40. The first one-way valve 40 is conducted, and the pressure oil in the rodless cavity 220 enters the rod cavity 210 through the first oil circuit a, the third oil circuit c, and the second oil circuit b.

[0071] The first solenoid directional valve 50 and the second solenoid directional valve 60 are in a normally closed state, that is, when the controller 10 sends an opening command to the first solenoid directional valve 50 or the second solenoid directional valve 60, the first solenoid directional valve 50 or the second solenoid directional valve 60 will only open, and the pressure oil will flow through the first solenoid directional valve 50 or the second solenoid directional valve 60.

[0072] That is, when the hydraulic cylinder 20 extends, the second electromagnetic directional valve 60 receives the opening instruction and opens, while the first electromagnetic directional valve 50 is in a closed state. When the hydraulic cylinder 20 retracts, the first electromagnetic directional valve 50 receives the opening instruction and opens, while the second electromagnetic directional valve 60 is in a closed state. That is, when the hydraulic cylinder 20 extends, the fourth oil circuit d is connected and the third oil circuit c is disconnected; when the hydraulic cylinder 20 retracts, the third oil circuit c is connected and the fourth oil circuit d is disconnected.

[0073] The above control method realizes bidirectional flow regeneration of the hydraulic cylinder 20, thereby improving the working efficiency of the device.

[0074] In one embodiment, if Figure 4 As shown, when the load changes greatly and the hydraulic cylinder 20 extends, the controller 10 sends a command to the proportional valve 30, and the pressure oil flows from the first outlet of the proportional valve 30 through the first oil path a into the rodless chamber 220. The controller 10 sends an opening command to the second electromagnetic directional valve 60, and the second electromagnetic directional valve 60 opens.

[0075] When the pressure of the pressure oil in the second oil circuit b is less than the opening pressure of the second balance valve 90, the pressure oil in the second oil circuit b flows into the second check valve 70, the second check valve 70 is turned on, and the pressure oil in the rod chamber 210 flows into the rodless chamber 220 via the second oil circuit b, the fourth oil circuit d, and the first oil circuit a.

[0076] When the pressure of the pressure oil in the second oil circuit b is greater than or equal to the opening pressure of the second balance valve 90 , the pressure oil flowing out of the rod chamber 210 flows through the second balance valve 90 and then flows into the oil tank.

[0077] Further, when the pressure of the pressure oil in the second oil circuit b is less than the opening pressure of the second balancing valve 90, the pressure oil flows into the first one-way valve 40 through the first control oil circuit e, so that the first one-way valve 40 is closed to achieve flow regeneration.

[0078] When the pressure generated by the pressure oil in the second oil circuit b is greater than or equal to the opening pressure in the second balancing valve 90, the pressure oil in the second oil circuit b flows to the oil cylinder through the second balancing valve 90, and at the same time, the pressure oil flows into the second one-way valve 70 through the second control oil circuit f, so that the second one-way valve 70 is closed, and the device is further automatically switched from the regenerative circuit to the non-regenerative circuit connection, thereby realizing high-pressure extension of the hydraulic cylinder 20 and overcoming the heavy load condition.

[0079] As Figure 5 shown, when the load changes greatly and the hydraulic cylinder 20 retracts, the controller 10 sends an instruction to the proportional valve 30, and the pressure oil flows from the second outlet of the proportional valve 30 through the second oil passage b into the rod chamber 210. The controller 10 sends an opening instruction to the first electromagnetic directional valve 50, and the first electromagnetic directional valve 50 opens.

[0080] When the pressure of the pressure oil in the first oil passage a is less than the opening pressure of the first balance valve 80, the pressure oil in the first oil passage a flows into the first check valve 40, and the first check valve 40 conducts. The pressure oil in the rodless chamber 220 flows into the rod chamber 210 through the first oil passage a, the third oil passage c, and the second oil passage b.

[0081] When the pressure of the pressure oil in the first oil passage a is greater than or equal to the opening pressure of the first balance valve 80, the pressure oil flowing out of the rodless chamber 220 flows through the first balance valve 80 and then into the fuel tank.

[0082] Furthermore, when the pressure of the pressure oil in the first oil passage a is less than the opening pressure of the first balance valve 80, the pressure oil flows through the second control oil passage f into the second check valve 70 to close the second check valve 70 to achieve regenerative flow.

[0083] When the pressure generated by the pressure oil in the first oil passage a is greater than or equal to the opening pressure of the first balance valve 80, the pressure oil in the first oil passage a flows through the second balance valve 90 and into the oil cylinder. At the same time, the pressure oil in the first oil passage flows through the first control oil passage e into the first check valve 40 to close the first check valve 40, further enabling the device to automatically switch from the regenerative circuit to the non-regenerative circuit connection and achieve the high-compression return of the hydraulic cylinder 20.

[0084] That is to say, the two-way regenerative circuit of the hydraulic cylinder 20 utilizes pressure transformation. When the pressure in the oil passage increases, the regenerative circuit automatically switches to the non-regenerative circuit connection. This control method improves the stability of the switching and increases the output force of the hydraulic cylinder 20. In addition, this control method can automatically switch according to the load size and can set the switching point at the highest pressure allowed by the device, improving the conversion rate of the kinetic energy generated by the device.

[0085] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An energy-saving hydraulic pressure maintaining device, characterized in that, Comprising: Hydraulic cylinder; Proportional valve, the first outlet of the proportional valve is connected to the rodless chamber of the hydraulic cylinder to form a first oil circuit, and the second outlet of the proportional valve is connected to the rod chamber of the hydraulic cylinder to form a second oil circuit; First check valve and first electromagnetic directional valve, the first check valve is connected to the first electromagnetic directional valve to form a third oil circuit, one end of the first electromagnetic directional valve is connected to the rodless chamber so that the first oil circuit can conduct unidirectionally to the third oil circuit, and one end of the first check valve is connected to the second oil circuit; Second check valve and second electromagnetic directional valve, the second check valve is connected to the second electromagnetic directional valve to form a fourth oil circuit, one end of the second electromagnetic directional valve is connected to the rod chamber so that the second oil circuit and the fourth oil circuit conduct unidirectionally, and one end of the second check valve is connected to the first oil circuit; Controller, electrically connected to the first electromagnetic directional valve and the second electromagnetic directional valve respectively to control one of the first electromagnetic directional valve and the second electromagnetic directional valve to open and the other to close so that one of the third oil circuit and the first oil circuit is connected and the other is closed, and one of the fourth oil circuit and the second oil circuit is connected and the other is closed; First balance valve and second balance valve, the first balance valve and the second balance valve are respectively connected to the first oil circuit and the second oil circuit, and the first balance valve is located between the connection of the third oil circuit and the first oil circuit and the proportional valve, and the second balance valve is located between the connection of the fourth oil circuit and the second oil circuit and the proportional valve; First control oil circuit, one end of which is connected to the first check valve, the other end of which is connected to the first oil circuit, and the connection of the first control oil circuit and the first oil circuit is located between the first balance valve and the proportional valve; Second control oil circuit, one end of which is connected to the second check valve, the other end of which is connected to the second oil circuit, and the connection of the second control oil circuit and the second oil circuit is located between the second balance valve and the proportional valve.

2. The energy-saving hydraulic pressure maintaining device according to claim 1, characterized in that, The first electromagnetic directional valve is located between the first check valve and the first oil circuit.

3. The energy-saving hydraulic pressure maintaining device according to claim 1, characterized in that, The second electromagnetic directional valve is located between the second check valve and the second oil circuit.

4. The energy-saving hydraulic pressure holding device according to claim 1, wherein Further comprising: Sensor, which is installed in the hydraulic cylinder, the sensor is connected to the controller, and the sensor is used to detect the displacement of the hydraulic cylinder in real time.

5. A control method for an energy-saving hydraulic pressure maintaining device, which is applied to the energy-saving hydraulic pressure maintaining device according to any one of claims 1-4, characterized in that, Comprising: When the hydraulic cylinder extends, the pressure oil flows from the first outlet of the proportional valve through the first oil circuit into the rodless chamber, and the controller sends an opening instruction to the second electromagnetic directional valve, the second electromagnetic directional valve opens, the pressure oil flows into the second check valve, the second check valve conducts, and the pressure oil in the rod chamber enters the rodless chamber through the second oil circuit, the fourth oil circuit, and the first oil circuit; When the hydraulic cylinder retracts, the pressure oil flows from the second outlet of the proportional valve through the second oil circuit into the rod chamber, and the controller sends an opening instruction to the first electromagnetic directional valve, the first electromagnetic directional valve opens, the pressure oil flows into the first check valve, the first check valve conducts, and the pressure oil in the rodless chamber enters the rod chamber through the first oil circuit, the third oil circuit, and the second oil circuit.

6. The method according to claim 5, applied to the energy-saving hydraulic pressure maintaining device according to claim 1, is characterized in that, Comprising: When the load changes greatly and the hydraulic cylinder extends, the controller sends an instruction to the proportional valve, and the pressure oil flows from the first outlet of the proportional valve through the first oil passage into the rodless cavity, and the second electromagnetic directional valve opens. When the pressure of the pressure oil in the second oil passage is less than the opening pressure of the second balance valve, the pressure oil in the second oil passage flows into the second check valve, the second check valve conducts, and the pressure oil in the rod cavity flows through the second oil passage, the fourth oil passage, and the first oil passage into the rodless cavity. When the pressure of the pressure oil in the second oil passage is greater than or equal to the opening pressure of the second balance valve, the pressure oil flowing out of the rod cavity flows through the second balance valve and then into the oil tank.

7. The method according to claim 6, characterized in that, Comprising: When the load changes greatly and the hydraulic cylinder retracts, the controller sends an instruction to the proportional valve, and the pressure oil flows from the second outlet of the proportional valve through the second oil passage into the rod cavity, and the first electromagnetic directional valve opens. When the pressure of the pressure oil in the first oil passage is less than the opening pressure of the first balance valve, the controller sends an opening instruction to the first electromagnetic directional valve, the pressure oil in the first oil passage flows into the first check valve, the first check valve conducts, and the pressure oil in the rodless cavity flows through the first oil passage, the third oil passage, and the second oil passage into the rod cavity. When the pressure of the pressure oil in the first oil passage is greater than or equal to the opening pressure of the first balance valve, the pressure oil flowing out of the rodless cavity flows through the first balance valve and then into the oil tank.

8. The method according to claim 7, characterized in that When the pressure of the pressure oil in the second oil passage is greater than the opening pressure of the second balance valve, the pressure oil flows through the second control oil passage into the second check valve to close the second check valve. When the pressure of the pressure oil in the first oil passage is greater than the opening pressure of the first balance valve, the pressure oil flows through the first control oil passage into the first check valve to close the first check valve.

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