Hydraulic jacking and pressure stabilizing module and hydraulic jacking system

Abstract

The present invention provides a hydraulic jacking and pressure stabilizing module, which includes an oil inlet pipeline, an oil return pipeline, an accumulator and a cartridge valve. The cartridge valve and the accumulator are sequentially installed on the oil inlet pipeline along the forward direction of the hydraulic oil. One main oil port of the cartridge valve is connected to the oil inlet pipeline, and the other main oil port of the cartridge valve is connected to the oil return pipeline. The control oil port of the cartridge valve is connected to the oil inlet pipeline, and a pilot oil pressure regulating valve is provided between the control oil port of the cartridge valve and the oil return pipeline. The combination of the cartridge valve and the pilot oil pressure regulating valve plays a role in stabilizing the oil pressure peak value of the oil inlet pipeline. The accumulator plays a role in storing and releasing the pressure energy of the oil inlet pipeline, achieving the purpose of absorbing the pressure pulse in the oil inlet pipeline and reducing the impact, and playing a role in pressure stabilization. When this hydraulic jacking and pressure stabilizing module is connected to the hydraulic jacking system, it can reduce the fluctuation of the oil pressure in the pipeline, so as to reduce the influence on the pre-stress deformation amount, and further play a role in stabilizing the jacking to ensure the product quality.

Description

Technical Field

[0001] The present invention relates to the field of metal additive manufacturing, and particularly to a hydraulic lifting and pressure stabilizing module and a hydraulic lifting system. Background Art

[0002] In planar surfacing additive manufacturing, after the cladding and deposition printing of a single layer of metal wire is completed, the additive deposition layer itself will shrink due to temperature drop. During the printing process, there will be a large temperature gradient between the additive deposition layer and the base substrate. During the cooling process, the temperature change amounts of the additive deposition layer and the base substrate are different, so the shrinkage amounts of the two layers are different. After the additive deposition layer completes cooling, there will be a pulling internal force on the base substrate, and the macroscopic manifestation after multi-layer deposition is the deformation and bending of the lower layer of deposited material. The accumulated pulling internal force of the upper layer material on the lower layer material may cause tearing inside the deposited material due to internal stress, resulting in defects and affecting product quality.

[0003] Based on the above-mentioned technical problems encountered, the inventor of the present invention proposed a technical solution capable of balancing internal stress during the research and production process, that is, using hydraulic lifting to provide an upward prestress to the base substrate before cladding printing, and removing the corresponding prestress after printing is completed. The compressive stress generated on the additive deposition layer during the restoration process of the base substrate is used to balance the internal stress generated during the cooling of the additive deposition layer. However, in the actual additive printing process, the prestress deformation amount provided by hydraulic lifting to the base substrate is a very small amount in the order of hundreds of micrometers. This makes the slightest fluctuation in the pressure of the pipeline oil during the hydraulic lifting process affect the prestress deformation amount. In this way, the purpose of stable lifting cannot be achieved, and thus the product quality cannot be better guaranteed. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a hydraulic lifting and pressure stabilizing module. By sequentially installing a cartridge valve and an accumulator along the forward direction of the hydraulic oil in the oil inlet pipeline, and connecting a pilot oil pressure regulating valve in the cartridge valve and the oil return pipeline, the pressure relief threshold of the cartridge valve is adjusted by adjusting the pilot oil pressure regulating valve, thereby determining the pressure relief threshold in the oil inlet pipeline, that is, stabilizing the pressure peak value of the working oil pressure in the oil inlet pipeline. The accumulator can absorb the pressure pulses in the oil inlet pipeline and reduce the impact, thereby achieving the purpose of stabilizing the oil pressure in the oil inlet pipeline. Connecting this hydraulic lifting module to the hydraulic lifting system can reduce the fluctuation of the oil pressure in the pipeline, reduce the influence on the prestress deformation amount, and thus play a role in stabilizing the lifting and ensuring product quality.

[0005] The technical solution of the present invention is realized as follows:

[0006] One of the objectives of the present invention is to disclose a hydraulic jacking pressure stabilizing module, which includes an oil inlet pipeline and an oil return pipeline, and also includes an accumulator and a cartridge valve. The cartridge valve and the accumulator are successively installed on the oil inlet pipeline along the forward direction of the hydraulic oil in the oil inlet pipeline. One of the main oil ports of the cartridge valve is connected to the oil inlet pipeline, and the other main oil port of the cartridge valve is connected to the oil return pipeline. The control oil port of the cartridge valve is connected to the oil inlet pipeline, and a pilot oil pressure regulating valve is provided between the control oil port of the cartridge valve and the oil return pipeline. By adjusting the pilot oil pressure regulating valve, the pressure relief valve threshold of the cartridge valve is adjusted, and then the pressure relief threshold in the oil inlet pipeline is determined, that is, the pressure peak value of the working oil pressure in the oil inlet pipeline is stabilized, so as to avoid the problem that the hydraulic system is pressurized beyond the working oil pressure due to abnormal oil pressure. Therefore, the combination of the cartridge valve and the pilot oil pressure regulating valve plays a role in stabilizing the pressure relief valve threshold of the oil inlet pipeline. The accumulator can store and release the pressure energy in the oil inlet pipeline to achieve the purpose of absorbing the pressure pulse in the oil inlet pipeline and reducing the impact, and then play a role in stabilizing the oil pressure in the oil inlet pipeline. When this hydraulic jacking pressure stabilizing module is connected to the hydraulic jacking system, the fluctuation of the oil pressure in the pipeline can be reduced to reduce the influence on the pre-stress deformation amount, and then play a role in stabilizing the jacking and ensuring the product quality.

[0007] Further, it also includes a pressure reducing valve, which is installed on the oil inlet pipeline between the accumulator and the cartridge valve. The oil drain port of the pressure reducing valve is connected to the oil return pipeline. Compared with the preliminary pressure regulating effect of the combination of the cartridge valve and the pilot oil pressure regulating valve on the pressure relief valve threshold of the oil inlet pipeline, the pressure reducing valve can further precisely regulate the oil pressure in the oil inlet pipeline. The oil pipeline pressure precisely regulated by the pressure reducing valve is finally called by the accumulator to further improve the stability.

[0008] Further, a first check valve is installed on the oil inlet pipeline between the pressure reducing valve and the cartridge valve. The first check valve can ensure that the oil pressure at the front end of the oil inlet pipeline will not fluctuate due to pressure loss, and play a role in further stabilizing the pressure.

[0009] Further, a two-position two-way solenoid valve is provided between the control oil port of the cartridge valve and the oil return pipeline. Specifically, this two-position two-way solenoid valve is in the cut-off position when energized and in the conducting position when de-energized. The working position of this two-position two-way solenoid valve is the cut-off position. When the hydraulic jacking module suddenly loses power, this two-position two-way solenoid valve conducts, so that the control oil port of the cartridge valve and the oil inlet pipeline are both connected to the oil return pipeline, so that the pipeline behind the first check valve, that is, the oil inlet pipeline between the first check valve and the hydraulic pump, can be automatically depressurized, avoiding the problem of excessive system vibration due to too much pressure oil in the pipeline after subsequent re-energization, and reducing the unstable factors of the system.

[0010] Further, an electric stop valve and a manual stop valve are connected in parallel between the oil inlet pipeline and the oil return pipeline. The electric stop valve and the manual stop valve can meet the pressure relief requirements in various scenarios. Among them, the electric stop valve is in a normally energized closed state, that is, it plays a pressure relief role when de-energized, improving adaptability.

[0011] Another object of the present invention is to disclose a hydraulic jacking system, including a fuel tank, a hydraulic pump, an oil inlet pipeline and an oil return pipeline. The fuel tank is connected to the oil inlet pipeline through the hydraulic pump, and the oil return pipeline is connected to the fuel tank. It also includes the above-mentioned hydraulic jacking and pressure stabilizing module and several jacking main cylinders. The jacking main cylinders are connected to the oil inlet pipeline and the oil return pipeline through a proportional reversing valve. Among them, the proportional reversing valve is a four-position four-way proportional valve. The four working positions of the proportional reversing valve can respectively meet the normal operation processes such as debugging, jacking, locking and retracting of the jacking main cylinders. The hydraulic jacking and pressure stabilizing module is arranged on the oil inlet pipeline between the proportional reversing valve and the hydraulic pump. Through the fuel tank and the hydraulic pump, hydraulic power is provided for the hydraulic jacking and pressure stabilizing module and the jacking main cylinders. Only by controlling the proportional reversing valve can the processes of jacking and locking of the jacking main cylinders be regulated to achieve the purpose of jacking the base substrate and providing upward prestress for the base substrate before additive printing. After printing is completed, by controlling the retraction of the jacking main cylinders, the operation of removing the prestress can be carried out. Setting the hydraulic jacking and pressure stabilizing module on the oil inlet pipeline and the oil return pipeline can play a role in stabilizing the oil pressure in the oil inlet pipeline, reducing the fluctuation of the oil pressure in the pipeline, thereby reducing the influence on the prestress deformation amount, and further ensuring that the jacking main cylinders can achieve the purpose of stable jacking and guaranteeing the product quality.

[0012] Further, it further includes a jacking sub-cylinder. The jacking main cylinder has a jacking main oil chamber and a return main oil chamber. Among them, the jacking main oil chamber is the working chamber where the piston of the jacking main cylinder will be jacked out after injecting hydraulic oil, and the return main oil chamber is the working chamber where the piston will retract into the jacking main cylinder after injecting hydraulic oil. The jacking sub-cylinder has a jacking sub-oil chamber and a return sub-oil chamber. The return sub-oil chamber communicates with the jacking main oil chamber. Specifically, the jacking sub-oil chamber is the working chamber where the piston of the jacking sub-cylinder will be jacked out after injecting hydraulic oil, and the return sub-oil chamber is the working chamber where the piston will retract into the jacking sub-cylinder after injecting hydraulic oil. The jacking sub-oil chamber and the return main oil chamber respectively communicate with the two working oil ports of the proportional directional valve. A displacement encoder is provided on the piston rod of the jacking sub-cylinder. The displacement encoder monitors and feedbacks the stroke of the piston rod of the jacking sub-cylinder being jacked out or retracted. During the jacking operation, the hydraulic oil in the oil inlet pipeline enters the jacking sub-oil chamber after passing through one of the working oil ports of the proportional directional valve, pushing the piston rod in the jacking sub-cylinder to jack outwards. At the same time, the hydraulic oil in the return sub-oil chamber will be pushed out by the piston and then enter the jacking main oil chamber to achieve the purpose of pushing the piston of the jacking main cylinder for the jacking operation. In this process, since the volume of the hydraulic oil jacked out in the return sub-oil chamber is equal to the volume of the hydraulic oil entering the jacking main oil chamber, therefore, the ratio of the pressure-bearing cross-sectional area of the jacking main cylinder to the pressure-bearing cross-sectional area of the jacking sub-cylinder is equal to the ratio of the jacking stroke of the piston of the jacking sub-cylinder to the jacking stroke of the piston of the jacking main cylinder. However, the pressure-bearing cross-sectional areas of the two are the design parameters of the known inner cavity of the oil cylinder. Therefore, only by measuring the displacement of the piston of the jacking sub-cylinder through the displacement encoder can the jacking displacement of the piston of the jacking main cylinder be calculated, and then the pre-stress deformation amount during the jacking of the jacking main cylinder can be calculated.

[0013] Further, it further includes a two-position four-way directional valve. The oil inlet pipeline communicates with two of the main oil ports of the two-position four-way directional valve. The other two main oil ports of the two-position four-way directional valve both communicate with the oil inlet of the proportional directional valve. The oil return port of the proportional directional valve is connected to the oil return pipeline, and the internal channels of the two-position four-way directional valve are connected in parallel. During the jacking process of injecting oil, it can effectively increase the pipeline flow rate. When the hydraulic jacking system enters the locking working position, only by controlling the internal channels of the two-position four-way directional valve to be connected to their respective parallel main oil ports can the cut-off function be achieved, further ensuring the hydraulic stability of the hydraulic jacking system when in the locking working position. Moreover, only by using one two-position four-way directional valve can the purpose of cutting off all jacking main cylinders be achieved, saving the usage cost of the cut-off valve.

[0014] Further, a positive-pressure connecting air pipe for conveying compressed air is provided inside the fuel tank, and the hydraulic lifting system is designed as a positive-pressure system. Compressed air with a pressure of 0.4 - 0.7 MPa is connected inside the fuel tank, which can help the hydraulic oil actively enter the cavities of each component when starting after shutdown.

[0015] Further, a manual adjustment pipe is connected to the pipeline between the return secondary oil cavity and the ejection main oil cavity. A second one-way valve is provided on the manual adjustment pipe. When the hydraulic lifting system is in the debugging working position, hydraulic oil is injected into or withdrawn from the manual adjustment pipe manually, so as to adjust the initial position of the piston in the cylinder body, which is convenient for calibration adjustment and improves accuracy.

[0016] The beneficial effects of the present invention: The cartridge valves and the pilot oil pressure regulating valves in the oil inlet pipeline and the oil return pipeline play a role in stabilizing the pressure peak of the working oil pressure in the oil inlet pipeline. The accumulator in the oil inlet pipeline can store and release the pressure energy in the oil inlet pipeline to absorb the pressure pulse in the oil inlet pipeline and reduce the impact, thereby stabilizing the oil pressure in the oil inlet pipeline. When the hydraulic lifting pressure stabilizing module is connected to the hydraulic lifting system, the fluctuation of the oil pressure in the pipeline can be reduced, so as to reduce the influence on the prestress deformation amount, and further play a role in stabilizing the lifting, ensuring the product quality. The pressure reducing valve in the oil inlet pipeline plays a role in further stabilizing the pressure; the first one-way valve can ensure that the oil pressure at the front end of the oil inlet pipeline, that is, the actuator end of the hydraulic system, will not fluctuate due to pressure loss, playing a role in further stabilizing the pressure; in this hydraulic lifting system, only by controlling and switching the flow directions of the proportional reversing valve and the two-position four-way reversing valve, the purpose of stable lifting can be achieved, ensuring the product quality. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0018] Figure 1 It is a connection relationship diagram of the hydraulic lifting pressure stabilizing module of the present invention;

[0019] Figure 2 It is a connection relationship diagram of the hydraulic lifting system of the present invention;

[0020] Figure 3 It is a connection schematic diagram of the two-position four-way reversing valve and the lifting main cylinder.

[0021] Attached drawing reference numerals: 1, oil inlet pipeline; 2, oil return pipeline; 3, accumulator; 4, cartridge valve; 5, pilot oil pressure regulating valve; 6, pressure reducing valve; 7, first check valve; 8, two-position two-way solenoid valve; 9, electric globe valve; 10, manual globe valve; 11, oil tank; 12, hydraulic pump; 13, jacking main cylinder; 131, main oil cavity for ejection; 132, main oil cavity for return stroke; 14, proportional directional valve; 15, jacking auxiliary cylinder; 151, auxiliary oil cavity for ejection; 152, auxiliary oil cavity for return stroke; 16, displacement encoder; 17, two-position four-way directional valve; 18, positive pressure gas connection pipe; 19, manual adjustment pipe; 20, second check valve. Specific implementation mode

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0023] See Figure 1 , a hydraulic jacking and pressure stabilizing module, including an oil inlet pipeline 1 and an oil return pipeline 2, further including an accumulator 3 and a cartridge valve 4. The cartridge valve 4 and the accumulator 3 are sequentially installed on the oil inlet pipeline 1 along the forward direction of the hydraulic oil in the oil inlet pipeline 1. One main oil port of the cartridge valve 4 is connected to the oil inlet pipeline 1, and the other main oil port of the cartridge valve 4 is connected to the oil return pipeline 2. The control oil port of the cartridge valve 4 is connected to the oil inlet pipeline 1, and a pilot oil pressure regulating valve 5 is provided between the control oil port of the cartridge valve 4 and the oil return pipeline 2. By adjusting the pilot oil pressure regulating valve 5, the pressure relief valve threshold of the cartridge valve 4 is adjusted, and then the pressure relief threshold in the oil inlet pipeline 1 is determined, that is, the pressure peak value of the working oil pressure in the oil inlet pipeline 1 is stabilized, so as to avoid the problem that the hydraulic system is pressurized beyond the working oil pressure due to abnormal oil pressure. Therefore, the combination of the cartridge valve 4 and the pilot oil pressure regulating valve 5 plays a role in stabilizing the pressure relief valve threshold of the oil inlet pipeline 1. The accumulator 3 can store and release the pressure energy in the oil inlet pipeline 1 to achieve the purpose of absorbing the pressure pulse in the oil inlet pipeline 1 and reducing the impact, and then play a role in stabilizing the oil pressure in the oil inlet pipeline 1. When this hydraulic jacking and pressure stabilizing module is connected to the hydraulic jacking system, the fluctuation of the oil pressure in the pipeline can be reduced, so as to reduce the influence on the pre-stress deformation amount, and then play a role in stabilizing the jacking and ensuring the product quality.

[0024] See Figure 1, it further includes a pressure reducing valve 6. The pressure reducing valve 6 is installed on the oil inlet pipeline 1 between the accumulator 3 and the cartridge valve 4. The oil drain port of the pressure reducing valve 6 is connected to the oil return pipeline 2. Compared with the preliminary pressure regulating effect of the combination of the cartridge valve 4 and the pilot oil pressure regulating valve 5 on the pressure relief valve value of the oil inlet pipeline 1, the pressure reducing valve 6 can further precisely regulate the oil pressure in the oil inlet pipeline 1. The oil pressure in the pipeline precisely regulated by the pressure reducing valve 6 is finally called by the accumulator 3, further improving the stability.

[0025] Preferably, a first check valve 7 is installed on the oil inlet pipeline 1 between the pressure reducing valve 6 and the cartridge valve 4. The first check valve 7 can ensure that the oil pressure at the front end of the oil inlet pipeline 1, that is, the actuator end of the hydraulic system, will not fluctuate due to pressure loss, playing a role in further stabilizing the pressure.

[0026] Preferably, a two-position two-way solenoid valve 8 is provided between the control oil port of the cartridge valve 4 and the oil return pipeline 2. Specifically, the two-position two-way solenoid valve 8 is in the cut-off position when energized and in the conducting position when de-energized. The normal working position of the two-position two-way solenoid valve 8 is the cut-off position. When the hydraulic jacking module suddenly loses power, the two-position two-way solenoid valve 8 is de-energized and conducts, so that the control oil port of the cartridge valve 4 and the oil inlet pipeline 1 are both connected to the oil return pipeline 2, so that the pipeline behind the first check valve 7, that is, the oil inlet pipeline 1 between the first check valve 7 and the hydraulic pump, can be automatically depressurized to avoid the problem of excessive system vibration due to too much pressure oil in the pipeline after subsequent re-energization, reducing the unstable factors of the system.

[0027] Preferably, an electric stop valve 9 and a manual stop valve 10 are connected in parallel between the oil inlet pipeline 1 and the oil return pipeline 2. The electric stop valve 9 and the manual stop valve 10 can meet the pressure relief requirements in various scenarios and improve the adaptability. In this embodiment, the electric stop valve 9 is in the normally energized state, that is, it plays a pressure relief role when de-energized.

[0028] See Figure 2 and Figure 3, a hydraulic jacking system, comprising an oil tank 11, a hydraulic pump 12, an oil inlet pipeline 1 and an oil return pipeline 2. The oil tank 11 is connected to the oil inlet pipeline 1 through the hydraulic pump 12, and the oil return pipeline 2 is connected to the oil tank 11. It further includes the above-mentioned hydraulic jacking pressure stabilizing module and several jacking main cylinders 13. In this embodiment, the number of jacking main cylinders 13 is at least two. The jacking main cylinders 13 are connected to the oil inlet pipeline 1 and the oil return pipeline 2 through a proportional reversing valve 14. Among them, the proportional reversing valve 14 is a four-position four-way proportional valve. The four working positions of the proportional reversing valve 14 can respectively meet the normal operation processes such as commissioning, jacking, locking and retracting of the jacking main cylinder 13. The hydraulic jacking pressure stabilizing module is arranged on the oil inlet pipeline 1 between the proportional reversing valve 14 and the hydraulic pump 12. Through the oil tank 11 and the hydraulic pump 12, hydraulic power is provided for the hydraulic jacking pressure stabilizing module and the jacking main cylinders 13. During jacking, only by controlling the proportional reversing valve 14 can the processes of jacking and locking of the jacking main cylinder 13 be regulated, so as to achieve the purpose of jacking the base substrate and providing upward prestress for the base substrate before additive printing. After printing is completed, by controlling the retraction of the jacking main cylinder, the operation of removing the prestress can be carried out. Setting the hydraulic jacking pressure stabilizing module on the oil inlet pipeline and the oil return pipeline can play a role in stabilizing the oil pressure in the oil inlet pipeline 1, reducing the fluctuation of the oil pressure in the pipeline, thereby reducing the influence on the prestress deformation amount, and further ensuring that the jacking main cylinder can achieve the purpose of stable jacking and guaranteeing the product quality.

[0029] Preferably, it further includes a jacking auxiliary oil cylinder 15. The jacking main oil cylinder 13 has a jacking main oil chamber 131 and a return main oil chamber 132. Among them, the jacking main oil chamber 131 is the working chamber where the piston of the jacking main oil cylinder 13 will be jacked out after injecting hydraulic oil, and the return main oil chamber 132 is the working chamber where the piston will retract into the jacking main oil cylinder after injecting hydraulic oil. The jacking auxiliary oil cylinder 15 has a jacking auxiliary oil chamber 151 and a return auxiliary oil chamber 152. The return auxiliary oil chamber 152 communicates with the jacking main oil chamber 131. Specifically, the jacking auxiliary oil chamber 151 is the working chamber where the piston of the jacking auxiliary oil cylinder 15 will be jacked out after injecting hydraulic oil, and the return auxiliary oil chamber 152 is the working chamber where the piston will retract into the jacking auxiliary oil cylinder 15 after injecting hydraulic oil. The jacking auxiliary oil chamber 151 and the return main oil chamber 132 respectively communicate with two working oil ports of the proportional directional valve 14. A displacement encoder 16 is provided on the piston rod of the jacking auxiliary oil cylinder 15. The displacement encoder 16 monitors and feeds back the stroke of the piston rod of the jacking auxiliary oil cylinder 15 being jacked out or retracted. During the jacking operation, the hydraulic oil in the oil inlet pipeline 1 enters the jacking auxiliary oil chamber 151 after passing through one of the working oil ports of the proportional directional valve 14, pushing the piston rod in the jacking auxiliary oil cylinder 14 to jack outwards. At the same time, the hydraulic oil in the return auxiliary oil chamber 152 will be pushed out by the piston and then enter the jacking main oil chamber 131 to achieve the purpose of pushing the piston of the jacking main oil cylinder 13 for jacking out operation. During this process, since the volume of the hydraulic oil jacked out in the return auxiliary oil chamber 152 is equal to the volume of the hydraulic oil entering the jacking main oil chamber 131, therefore, the ratio of the pressure-bearing cross-sectional area of the jacking main oil cylinder 13 to the pressure-bearing cross-sectional area of the jacking auxiliary oil cylinder 15 is equal to the ratio of the jacking stroke of the piston of the jacking auxiliary oil cylinder 15 to the jacking stroke of the piston of the jacking main oil cylinder 13. However, the pressure-bearing cross-sectional areas of the two are the known design parameters of the inner cavity of the oil cylinder. Therefore, only by measuring the displacement of the piston of the jacking auxiliary oil cylinder 15 through the displacement encoder 16, the jacking displacement of the piston of the jacking main oil cylinder 13 can be calculated, and then the pre-stress deformation amount during the jacking of the jacking main oil cylinder 13 can be calculated.

[0030] Preferably, it further includes a two-position four-way directional valve 17. The oil inlet pipeline 1 communicates with two of the main oil ports of the two-position four-way directional valve 17. In this embodiment, the oil inlet pipeline 1 specifically communicates with the oil inlet port and one of the working oil ports of the two-position four-way directional valve 17. The other two main oil ports of the two-position four-way directional valve 17 (i.e., the oil return port and the other working oil port of the two-position four-way directional valve 17) both communicate with the oil inlet ports of all the proportional directional valves 14. The oil return ports of all the proportional directional valves 14 are all connected to the oil return pipeline 2, and the internal channels of the two-position four-way directional valve 17 are connected in parallel. During the jacking process of injecting oil, it can effectively increase the pipeline flow rate. When the hydraulic jacking system enters the locked working position, only need to control the internal channels of the two-position four-way directional valve 17 to connect their respective parallel main oil ports. Figure 3As shown, it can play a cut-off role, further ensuring the hydraulic stability of the hydraulic jacking system when in the locked working position. Moreover, only by using a two-position four-way directional control valve 17 can the purpose of cutting off all the jacking main cylinders 13 be achieved, saving the usage cost of the cut-off valve.

[0031] Preferably, a positive pressure air supply pipe 18 for conveying compressed air is provided in the fuel tank 11, and the hydraulic jacking system is designed as a positive pressure system. By connecting 0.4 - 0.7 MPa compressed air inside the fuel tank 11, it can help the hydraulic oil actively enter the cavities of each component when starting up after shutdown.

[0032] Preferably, a manual adjustment pipe 19 is connected to the pipeline between the return stroke secondary oil chamber 152 and the jacking main oil chamber 131. A second one-way valve 20 is provided on the manual adjustment pipe 19. When the hydraulic jacking system is in the debugging working position, by manually injecting or extracting hydraulic oil into the manual adjustment pipe 19, the purpose of adjusting the initial position of the piston in the cylinder can be achieved, which is convenient for calibration adjustment and improves the accuracy.

[0033] Among them, in this embodiment, referring to Figure 2 and Figure 3 , the proportional directional control valve 14 is a four-position four-way proportional directional control valve. The four working positions are, from left to right in sequence: debugging position, jacking position, locked working position, and return stroke position; the specific connection mode is: the oil inlet pipeline 1 is connected to the oil inlet of the proportional directional control valve 14 after passing through the two-position four-way directional control valve 17. The oil return port of the proportional directional control valve 14 is connected to the oil return pipeline 2. The return stroke main oil chamber is connected to one of the working oil ports of the proportional directional control valve. This working oil port is the working oil port connected to the oil inlet when the proportional directional control valve 14 is in the jacking position, serving as the return stroke path of the jacking main cylinder. The jacking secondary oil chamber 151 is connected to the remaining working oil port of the proportional directional control valve 14. The working oil port connected to the jacking secondary oil chamber 151 is the working oil port connected to the oil return port when the proportional directional control valve 14 is in the jacking position.

[0034] When the hydraulic jacking system is in the debugging position, the proportional directional control valve 14 is in the first position. At this time, the hydraulic oil can be manually injected or extracted into the manual adjustment pipe 19 to adjust the initial position of the piston of the jacking main cylinder;

[0035] Subsequently, control the proportional directional control valve 14 to switch to the second position, that is, the jacking position. At this time, the two-position four-way directional control valve 17 is in the de-energized state. The hydraulic oil in the oil inlet pipeline 1 enters the jacking secondary oil chamber 151 after passing through the two-position four-way directional control valve 17 and the proportional directional control valve 14, pushing the piston of the jacking secondary cylinder 15, and then pushing the piston of the jacking main cylinder 13 to perform the jacking movement to complete the jacking operation. When the piston of the jacking main cylinder 13 jacks out to the predetermined position, the proportional directional control valve 14 jumps to the third position, that is, the locked working position;

[0036] When the proportional directional valve 14 is in the third working position, the hydraulic pipelines of the jacking auxiliary oil chamber 151 and the return main oil chamber 132 are cut off, so that the piston of the jacking main cylinder 13 can be stably in the jacking state. At the same time, the two-position four-way directional valve 17 is energized to cut off the hydraulic oil in the oil inlet pipeline 1. At this time, the two-position four-way directional valve 17 acts as a stop valve to further ensure the hydraulic stability of the hydraulic jacking system when it is in the locked working position;

[0037] After the printing operation is completed and the prestress needs to be cancelled, only need to control the proportional directional valve 14 to make it in the fourth working position, that is, the return stroke working position, and make the two-position four-way directional valve 17 de-energized. At this time, the hydraulic oil in the oil inlet pipeline 1 enters the return main oil chamber 132 after passing through the two-position four-way directional valve 17 and the proportional directional valve 14, pushing the piston of the jacking main cylinder 13 to descend and return. At the same time, the hydraulic oil in the jacking auxiliary oil chamber 151 directly returns to the oil return pipeline 2 through the oil return port of the proportional directional valve 14. Thus, the hydraulic jacking system completes a complete operation of prestress supply and cancellation. Repeating the above process can perform a new prestress supply and cancellation operation.

[0038] In addition, in order to further stabilize the system and prevent the reverse flow of hydraulic oil, a cartridge valve acting as a check valve can also be installed on the oil inlet pipeline.

[0039] The beneficial effects of this embodiment: The cartridge valve and the pilot oil pressure regulating valve in the oil inlet pipeline and the oil return pipeline play a role in stabilizing the pressure peak of the working oil pressure in the oil inlet pipeline. The accumulator in the oil inlet pipeline can store and release the pressure energy in the oil inlet pipeline to achieve the purpose of absorbing the pressure pulse in the oil inlet pipeline and reducing the impact, thereby playing a role in stabilizing the oil pressure in the oil inlet pipeline. When the hydraulic jacking pressure stabilizing module is connected to the hydraulic jacking system, it can reduce the fluctuation of the oil pressure in the pipeline to reduce the influence on the prestress deformation amount, and thus play a role in stabilizing the jacking, ensuring the product quality. The pressure reducing valve in the oil inlet pipeline plays a role in further stabilizing the pressure; the first check valve can ensure that the oil pressure at the front end of the oil inlet pipeline, that is, the actuator end of the hydraulic system, will not fluctuate due to pressure loss, playing a further role in stabilizing the pressure; in this hydraulic jacking system, only need to control and switch the flow direction of the proportional directional valve and the two-position four-way directional valve to achieve the purpose of stable jacking and ensure the product quality.

[0040] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0041] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A hydraulic lifting system, comprising an oil tank, a hydraulic pump, an oil inlet pipeline and an oil return pipeline. The oil tank is connected to the oil inlet pipeline through the hydraulic pump, and the oil return pipeline is connected to the oil tank. It is characterized in that, It also includes a lifting auxiliary cylinder, a hydraulic lifting pressure stabilizing module and a plurality of lifting main cylinders. The hydraulic lifting pressure stabilizing module includes an accumulator and a cartridge valve. The cartridge valve and the accumulator are sequentially installed on the oil inlet pipeline along the forward direction of the hydraulic oil in the oil inlet pipeline. One of the main oil ports of the cartridge valve is connected to the oil inlet pipeline, and the other main oil port of the cartridge valve is connected to the return oil pipeline. The control oil port of the cartridge valve is connected to the oil inlet pipeline, and a pilot oil pressure regulating valve is provided between the control oil port of the cartridge valve and the return oil pipeline; the lifting main cylinder is connected to the oil inlet pipeline and the return oil pipeline through a proportional reversing valve, and the hydraulic lifting pressure stabilizing module is provided on the proportional reversing valve. The oil inlet pipeline between the reversing valve and the hydraulic pump is as follows; the lifting main oil cylinder has a main oil chamber for ejection and a main oil chamber for return stroke, the lifting auxiliary oil cylinder has an auxiliary oil chamber for ejection and an auxiliary oil chamber for return stroke, the auxiliary oil chamber for return stroke is connected with the main oil chamber for ejection, the auxiliary oil chamber for ejection and the main oil chamber for return stroke are respectively connected with two working oil ports of the proportional reversing valve, a displacement encoder is provided on the piston rod of the lifting auxiliary oil cylinder, the displacement encoder monitors and feeds back the ejection or retraction stroke of the piston rod of the lifting auxiliary oil cylinder; an electric stop valve and a manual stop valve are connected in parallel between the oil inlet pipeline and the oil return pipeline; a positive pressure air pipe for conveying compressed air is provided in the oil tank.

2. The hydraulic jacking system according to claim 1, wherein It also includes a pressure reducing valve, which is installed on the oil inlet pipeline between the accumulator and the cartridge valve, and the oil drain port of the pressure reducing valve is connected to the oil return pipeline.

3. The hydraulic jacking system according to claim 2, wherein, A first one-way valve is installed on the oil inlet pipeline between the pressure reducing valve and the cartridge valve.

4. The hydraulic jacking system according to any one of claims 1 to 3, characterized in that, A two-position two-way solenoid valve is arranged between the control oil port of the cartridge valve and the oil return pipeline.

5. The hydraulic jacking system according to claim 1, wherein It also includes a two-position four-way reversing valve, the oil inlet pipeline is connected to two main oil ports of the two-position four-way reversing valve, the other two main oil ports of the two-position four-way reversing valve are connected to the oil inlet of the proportional reversing valve, and the oil return port of the proportional reversing valve is connected to the oil return pipeline.

6. The hydraulic jacking system according to claim 1, characterized in that, A manual regulating pipe is connected to the pipeline between the return auxiliary oil chamber and the ejection main oil chamber, and a second one-way valve is arranged on the manual regulating pipe.

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