A catapult hydraulic system and its control method

Abstract

The present invention discloses an ejection hydraulic system and its control method, which includes an ejection hydraulic cylinder, an oil tank, a hydraulic pump, an assist hydraulic cylinder and an accumulator. An ejection piston and a pull rod are arranged inside the ejection hydraulic cylinder; an end cover is provided at the opening of the ejection hydraulic cylinder, and a vent hole and an oil delivery hole are provided on the outer peripheral wall of the ejection hydraulic cylinder; one end of the pull rod is connected to the ejection piston, and the other end passes through the end cover; the oil tank is connected to the hydraulic pump, the hydraulic pump is connected to the accumulator through a first oil pipe, and a first direction control valve is provided on the first oil pipe; a second oil pipe is connected to the first oil pipe, the second oil pipe is connected to the oil delivery hole of the ejection hydraulic cylinder, and a stop valve is provided on the second oil pipe; when the ejection piston abuts against the end cover, the ejection piston blocks the oil delivery hole of the ejection hydraulic cylinder; the assist hydraulic cylinder is respectively connected to the hydraulic pump and the oil tank through a second direction control valve, and the piston rod in the assist hydraulic cylinder abuts against the pull rod. The present invention has the advantages of fast ejection speed, short response time, good consistency and high reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic systems. More specifically, the present invention is an ejection hydraulic system and its control method. Background Art

[0002] There are various ways to launch an object to be launched, such as hand-throwing, vertical takeoff, aerial delivery, rocket boost, runway taxiing, vehicle-borne takeoff, and ejection takeoff. And there are also various ejection technologies, such as rubber rope ejection, electromagnetic ejection, hydraulic ejection, and pneumatic ejection.

[0003] In the hydraulic system related to ejection, most of the components triggering the ejection action are hydraulic control components such as electromagnetic directional control valves. Using this method will have the following problems: due to the short acceleration stroke of the hydraulic cylinder, if there are hydraulic control components between the accumulator and the hydraulic cylinder, its commutation over-current resistance and commutation delay will reduce the disengagement speed of the ejection object. If the hydraulic control component has a jamming phenomenon, it will lead to mission failure and cause unbearable mission losses.

[0004] Therefore, how to change the ejection triggering method to form an ejection hydraulic system with fast ejection speed, short response time, good consistency, and high reliability has become a technical problem that needs to be solved urgently by those skilled in the art and the focus of continuous research. Summary of the Invention

[0005] To solve the technical problem that in the existing ejection hydraulic system, when using a hydraulic control component to trigger ejection, it is easy to have a jamming phenomenon, resulting in the failure of the ejection mission, the present invention innovatively provides an ejection hydraulic system. Starting from the perspective of changing the ejection triggering method, no hydraulic control component is provided between the ejection hydraulic cylinder and the accumulator, and the boost hydraulic cylinder is used as the triggering component in the ejection process, which has the advantages of fast ejection speed, short response time, good consistency, and high reliability.

[0006] To achieve the above technical objectives, an embodiment of the present invention discloses an ejection hydraulic system, including: an ejection hydraulic cylinder, a fuel tank, a hydraulic pump, an assisting hydraulic cylinder, and an accumulator. An ejection piston and a pull rod are provided inside the ejection hydraulic cylinder; one end of the ejection hydraulic cylinder is closed and the other end is open; the ejection hydraulic cylinder is provided with an end cover for closing its opening. An air vent hole is provided on the outer peripheral wall of the closed end of the ejection hydraulic cylinder, and an oil delivery hole is provided on the outer peripheral wall of the open end of the ejection hydraulic cylinder; one end of the pull rod is fixedly connected to the ejection piston, and the other end of the pull rod passes through the end cover; the fuel tank is connected to the hydraulic pump, and the hydraulic pump is connected to the accumulator through a first oil pipe. A first direction control valve is provided on the first oil pipe; one end of the first oil pipe between the first direction control valve and the accumulator is connected to one end of a second oil pipe, and the other end of the second oil pipe is connected to the oil delivery hole of the ejection hydraulic cylinder. A stop valve is provided on the second oil pipe; when the ejection piston abuts against the end cover, the ejection piston blocks the oil delivery hole of the ejection hydraulic cylinder; the assisting hydraulic cylinder is respectively connected to the hydraulic pump and the fuel tank through a second direction control valve, and the piston rod in the assisting hydraulic cylinder abuts against the pull rod.

[0007] Further, in an ejection hydraulic system of the present invention, a pre-pressure oil circuit is provided in the inner wall of the ejection hydraulic cylinder. The first port of the pre-pressure oil circuit is communicated with the pore wall of the oil delivery hole, and the second port of the pre-pressure oil circuit is communicated with the inner peripheral wall of the ejection hydraulic cylinder, and the second port of the pre-pressure oil circuit is located below the oil delivery hole.

[0008] Further, in an ejection hydraulic system of the present invention, a transition groove is provided along the circumferential direction of the inner peripheral wall of the ejection hydraulic cylinder. The notch of the transition groove is smoothly transitioned with the inner peripheral wall of the ejection hydraulic cylinder through an arc surface, and one end port of the oil delivery hole is communicated with the bottom of the transition groove.

[0009] Further, in an ejection hydraulic system of the present invention, first flanges and second flanges that are slidably and sealingly fitted with the inner peripheral wall of the ejection hydraulic cylinder are provided at both ends of the ejection piston. A pressure-bearing groove is formed between the first flange and the second flange. When the first flange abuts against the end cover, the pressure-bearing groove is aligned with the oil delivery hole.

[0010] Further, in an ejection hydraulic system of the present invention, a pin hydraulic cylinder is further included. The pin hydraulic cylinder is respectively connected to the hydraulic pump and the fuel tank through a third direction control valve. The piston rod of the pin hydraulic cylinder is connected to the pull rod or the ejection mechanism, and is used to maintain the initial position of the pull rod or the ejection mechanism.

[0011] Further, in an ejection hydraulic system of the present invention, a check valve is provided on the first oil pipe between the hydraulic pump and the first direction control valve.

[0012] Furthermore, the present invention provides an ejection hydraulic system, wherein a first pressure sensor is provided on the second oil pipe between the accumulator and the stop valve, and a second pressure sensor is provided on the end cover of the ejection hydraulic cylinder.

[0013] Furthermore, the present invention provides an ejection hydraulic system, which also includes a third oil pipe, one end of the third oil pipe is connected to the rod chamber of the ejection hydraulic cylinder through an end cover, the other end of the third oil pipe is connected to the oil tank, and a throttle valve is provided on the third oil pipe.

[0014] The present invention also discloses a control method for an ejection hydraulic system, which is applied to the above ejection hydraulic system. The control method includes: a charging step, a maintaining step, a triggering step and an ejection step:

[0015] The charging step comprises:

[0016] The piston in the ejection hydraulic cylinder is pressed against the end cover so that the ejection piston is blocked at the oil delivery hole;

[0017] Close the stop valve and start the hydraulic pump;

[0018] Control the first directional control valve to switch on and off to charge the accumulator; when the pressure in the accumulator reaches a predetermined value, control the first directional control valve to switch off and off to disconnect the accumulator from the hydraulic pump, thereby shutting down the hydraulic pump;

[0019] The maintaining step comprises:

[0020] Ensure that the booster hydraulic cylinder has a retracted signal, and ensure that the pin hydraulic cylinder has an extended signal;

[0021] Open the stop valve;

[0022] The triggering step includes:

[0023] Start the hydraulic pump;

[0024] Control the third directional control valve to energize and reverse the direction to retract the pin hydraulic cylinder into place;

[0025] Control the second directional control valve to switch on and make the piston rod of the booster hydraulic cylinder push the pull rod of the ejection hydraulic cylinder, so that the ejection piston slides away from the oil delivery hole;

[0026] The ejection step comprises:

[0027] The oil in the accumulator enters the rod chamber of the ejection hydraulic cylinder through the oil delivery hole, and the ejection piston drives the pull rod to accelerate the retraction.

[0028] Furthermore, the present invention provides a control method for an ejection hydraulic system, wherein

[0029] The charging step also includes:

[0030] Detect whether the boost hydraulic cylinder has retracted in place. If not, control the second directional control valve to energize and reverse to retract the boost hydraulic cylinder in place;

[0031] Detect whether the pin hydraulic cylinder has extended in place. If not, control the third directional control valve to energize and reverse to extend the pin hydraulic cylinder in place;

[0032] The holding step further includes:

[0033] After opening the stop valve, detect whether the pressures of the first pressure sensor and the second pressure sensor are within the set threshold range. If not, control the first directional control valve to energize and reverse to replenish the pressure of the accumulator.

[0034] The beneficial effects of the present invention are as follows: The present invention uses an accumulator as an energy storage element and realizes the hydraulic ejection requirement in the form of the rapid retraction in place of the ejection hydraulic cylinder. It can release a huge power within 0.5 s, and the peak power can reach 10,000 KW, instantly accelerating the ejection object to the required speed. Only a stop valve is provided on the hydraulic circuit from the accumulator to the ejection hydraulic cylinder. The stop valve is closed when the accumulator stores energy and opened when ejection is required. The high-pressure oil in the accumulator directly acts on the ejection piston in the ejection hydraulic cylinder, making the hydraulic circuit between the accumulator and the ejection hydraulic cylinder form a complete passage. When ejection needs to be triggered, a small displacement is triggered for the pull rod in the ejection hydraulic cylinder by the boost hydraulic cylinder, and the oil in the accumulator directly acts on the ejection piston surface to complete the ejection. There is no obstacle between the accumulator and the ejection hydraulic cylinder, making the present invention have the advantages of fast ejection speed, short response time, good consistency, and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a schematic structural diagram of a ejection hydraulic system of the present invention;

[0036] Figure 2 is Figure 1 a partial enlarged structural diagram of part A in DETAILED DESCRIPTION OF THE INVENTION

[0037] The following will explain and illustrate in detail a ejection hydraulic system of the present invention with reference to the accompanying drawings of the specification.

[0038] As Figure 1 and in combination with Figure 2As shown in the figure, an embodiment of the present invention discloses an ejection hydraulic system, which specifically includes: an ejection hydraulic cylinder 1, an oil tank 2, a hydraulic pump 3, an assisting hydraulic cylinder 4, and an accumulator 5. An ejection piston 6 and a pull rod 7 are arranged inside the ejection hydraulic cylinder 1; one end of the ejection hydraulic cylinder 1 is closed and the other end is open. A end cover 11 for closing the opening is provided on the ejection hydraulic cylinder 1. A vent hole 12 is provided on the outer peripheral wall of the ejection hydraulic cylinder 1 at the closed end, and an oil delivery hole 13 is provided on the outer peripheral wall of the ejection hydraulic cylinder 1 at the open end; one end of the pull rod 7 is fixedly connected to the ejection piston 6, and the other end of the pull rod 7 passes through the end cover 11; the oil tank 2 is connected to the hydraulic pump 3, and the hydraulic pump 3 is connected to the accumulator 5 through a first oil pipe 8. A first direction control valve 81 is provided on the first oil pipe 8; one end of the first oil pipe 8 between the first direction control valve 81 and the accumulator 5 is connected to one end of a second oil pipe 9, and the other end of the second oil pipe 9 is connected to the oil delivery hole 13 of the ejection hydraulic cylinder 1. A stop valve 91 is provided on the second oil pipe 9; when the ejection piston 6 abuts against the end cover 11, the ejection piston 6 blocks the oil delivery hole 13 of the ejection hydraulic cylinder 1; the assisting hydraulic cylinder 4 is respectively connected to the hydraulic pump 3 and the oil tank 2 through a second direction control valve 41, and the piston rod in the assisting hydraulic cylinder 4 abuts against the pull rod 7.

[0039] During actual use, in the initial state, the pull rod 7 completely extends out from the end cover 11 of the ejection hydraulic cylinder 1. The extending end of the pull rod 7 is connected to the ejection mechanism. The ejection piston 6 just blocks the oil delivery hole 13 on the ejection hydraulic cylinder 1. The assisting hydraulic cylinder 4 is in the retracted state, and the stop valve 91 is in the closed state. When it is necessary to charge the accumulator 5, start the hydraulic pump 3 to make the first direction control valve 81 energized and commutate. The first direction control valve 81 is switched from the off state to the on state. The oil pumped out by the hydraulic pump 3 is filled into the accumulator through the first oil pipe 8. When the pressure in the accumulator 5 reaches the predetermined value, turn off the hydraulic pump 3 to make the first direction control valve 81 de-energized and commutate. The first direction control valve 81 is switched from the on state to the off state, and the charging of the accumulator 5 is completed; when it is necessary to perform an ejection operation, first open the stop valve 91 and keep the stop valve 91 in the on state, so that the oil in the accumulator 5 directly acts on the ejection piston 6 and waits for the ejection to be triggered; then make the second direction control valve 41 energized and commutate. The oil pumped out by the hydraulic pump 3 enters the rodless cavity of the assisting hydraulic cylinder 4, so that the piston rod in the assisting hydraulic cylinder 4 extends out. Because the piston rod in the assisting hydraulic cylinder 4 abuts against the pull rod 7, after the piston rod in the assisting hydraulic cylinder 4 extends out, it will push the ejection piston 6 to slide away from the oil delivery hole 13 on the ejection hydraulic cylinder 1; finally, the oil in the accumulator 5 will directly act on the ejection piston 6, and the ejection piston 6 will drive the pull rod 7 to quickly retract, driving the ejection object to move and completing the ejection.

[0040] In this embodiment, an accumulator 5 is used as an energy storage element to meet the hydraulic ejection requirements in the form of the rapid retraction of the pull rod 7 in the ejection hydraulic cylinder 1 to its in-place position. It can release a huge amount of power within 0.5 s, and the peak power can reach 10,000 KW, instantly accelerating the ejection object to the required speed. Only a stop valve 91 is provided on the second oil pipe 9 from the accumulator 5 to the ejection hydraulic cylinder 1. The stop valve 91 is closed when the accumulator 5 stores energy and opened when ejection is required. The high-pressure oil in the accumulator 5 directly acts on the ejection piston 6 in the ejection hydraulic cylinder 1, making the second oil pipe 9 between the accumulator 5 and the ejection hydraulic cylinder 1 form a complete passage. When ejection needs to be triggered, a small displacement is triggered for the pull rod 7 in the ejection hydraulic cylinder 1 by the boosting hydraulic cylinder 4. The oil in the accumulator 5 directly acts on the surface of the ejection piston 6, and the ejection piston 6 drives the pull rod 7 to quickly retract to complete the ejection. There is no obstruction between the accumulator 5 and the ejection hydraulic cylinder 1, making the present invention have the advantages of fast ejection speed, short response time, good consistency, and high reliability.

[0041] In an embodiment of the present invention, a pre-pressure oil path 14 is provided in the inner wall of the ejection hydraulic cylinder 1. The first port of the pre-pressure oil path 14 is communicated with the wall of the oil delivery hole 13, and the second port of the pre-pressure oil path 14 is communicated with the inner peripheral wall of the ejection hydraulic cylinder 1, and the second port of the pre-pressure oil path 14 is located below the oil delivery hole 13. Through the above settings, when the ejection piston 6 has not completely slid away from the oil delivery hole 13 on the ejection hydraulic cylinder 1, the oil flowing out of the accumulator 5 first passes through the pre-pressure oil path 14 and is communicated with the rod chamber of the ejection hydraulic cylinder 1, making the pressure in the rod chamber of the ejection hydraulic cylinder 1 consistent with the pressure at the oil delivery hole 13 on the ejection hydraulic cylinder 1, so that the ejection hydraulic cylinder 1 first obtains a relatively large basic pressure, and the ejection piston 6 receives a greater pushing effect. Secondly, generally, a sealing ring is provided between the ejection piston 6 and the ejection hydraulic cylinder 1, and the sealing performance between the two is achieved by providing a sealing ring on the ejection piston 6. Through the above settings, when the sealing ring passes through the oil delivery hole 13, the pressure on the side of the oil delivery hole 1 of the sealing ring is consistent with the pressure in the rod chamber of the ejection hydraulic cylinder 1, which can effectively prevent the sealing ring from being extruded by the high-pressure hydraulic oil and increase the overall reliability of the ejection hydraulic system.

[0042] In an embodiment of the present invention, a transition groove 15 is provided along the circumferential direction of the inner peripheral wall of the ejection hydraulic cylinder 1, and a smooth transition is made between the notch of the transition groove 15 and the inner peripheral wall of the ejection hydraulic cylinder 1 through an arc surface 16, so that one end port of the oil delivery hole 13 communicates with the bottom of the transition groove 15. Through the above arrangement, when the sealing ring on the ejection piston 6 passes through the oil delivery hole 13, it will pass through the transition groove 15 and the arc surface 16, making the movement of the ejection piston 6 smoother. At the same time, it can also prevent the phenomenon that the sealing ring on the ejection piston 6 is cut by the oil delivery hole 13 (that is, the situation where the oil delivery hole 13 cuts the sealing ring provided on the ejection piston 6), improve the service life of the sealing ring, and enhance the overall stability of the ejection hydraulic system.

[0043] In an embodiment of the present invention, a first flange 61 and a second flange 62 that are slidably and sealingly fitted with the inner peripheral wall of the ejection hydraulic cylinder 1 are provided at both ends of the ejection piston 6, so that a pressure-bearing groove 63 is formed between the first flange 61 and the second flange 62, and when the first flange 61 abuts against the end cover 11, the pressure-bearing groove 63 is aligned with the oil delivery hole 13. Through the above arrangement, the contact area of the oil flowing out from the accumulator 5 acting on the ejection piston 6 can be increased, so that the ejection piston 6 can withstand a greater pressure of the oil from the accumulator 5, enabling the ejection piston 6 to obtain a greater initial pressure, improving the ejection speed and shortening the response time.

[0044] In an embodiment of the present invention, a pin hydraulic cylinder 10 is further provided, and the pin hydraulic cylinder 10 is respectively connected to the hydraulic pump 3 and the fuel tank 2 through a third direction control valve 101, and the piston rod of the pin hydraulic cylinder 10 is connected to the pull rod 7 or the ejection mechanism for maintaining the initial position of the pull rod 7 or the ejection mechanism. Through the above arrangement, the pin hydraulic cylinder 10 can realize the telescopic movement of the piston rod in the pin hydraulic cylinder 10 through the third direction control valve 101. In actual application, after the piston rod in the pin hydraulic cylinder 10 extends, it directly acts on the pull rod 7 or the ejection mechanism to prevent the pull rod 7 or the ejection mechanism from being abnormally triggered, enhancing the overall safety of the ejection hydraulic system.

[0045] In an embodiment of the present invention, a one-way valve 82 is provided on the first oil pipe 8 between the hydraulic pump 3 and the first direction control valve 81. The one-way valve 82 can prevent the oil in the accumulator 5 from flowing back, keeping the accumulator 5 within a certain pressure range after charging, and enhancing the overall reliability of the ejection hydraulic system.

[0046] In an embodiment of the present invention, a first pressure sensor 92 is provided on the second oil pipe 9 between the accumulator 5 and the stop valve 91, and a second pressure sensor 17 is provided on the end cover 11 of the ejection hydraulic cylinder 1. The pressure of the accumulator 5 can be detected in real time through the first pressure sensor 92, and the pressure in the rodless cavity of the ejection hydraulic cylinder 12 can be detected in real time through the second pressure sensor 17, so as to perform subsequent remedies when the required pressure is not met, ensuring the overall stability of the system.

[0047] In one embodiment of the present invention, a third oil pipe 18 is further included, one end of the third oil pipe 18 is connected to the rod chamber of the ejection hydraulic cylinder 1 through the end cover 11, and the other end of the third oil pipe 18 is connected to the oil tank 2, and a throttle valve 181 is provided on the third oil pipe 18. Through the above arrangement, the oil in the rod chamber of the ejection hydraulic cylinder 1 can be recovered after the launch is completed. Specifically, by adjusting the throttle valve 181, the oil in the rod chamber of the ejection hydraulic cylinder 1 flows back to the oil tank 2 through the third oil pipe 18, so as to realize the repeated ejection requirement.

[0048] It should be noted that the first directional control valve 81 can adopt a two-position two-way solenoid reversing valve; the second directional control valve 41 and the third directional control valve 101 can adopt a three-position four-way solenoid reversing valve; and a fourth oil pipe can be connected to the first oil pipe 8 between the first directional control valve 81 and the hydraulic pump 3, and an overflow valve can be installed on the fourth oil pipe, and the other end of the overflow valve is connected to the oil tank to control the operating pressure.

[0049] The embodiment of the present invention further provides a control method of an ejection hydraulic system, which is applied to the above ejection hydraulic system. The control method specifically includes: a charging step, a holding step, a triggering step and an ejection step:

[0050] The charging steps include:

[0051] The piston in the ejection hydraulic cylinder 1 is pressed against the end cover 11, so that the ejection piston 6 is blocked at the oil delivery hole 13;

[0052] Close the stop valve 91 and start the hydraulic pump 3;

[0053] The first directional control valve 81 is controlled to be powered on and reversed to charge the accumulator 5; when the pressure in the accumulator 5 reaches a predetermined value, the first directional control valve 81 is controlled to be powered off and reversed to disconnect the accumulator 5 from the hydraulic pump 3, thereby shutting down the hydraulic pump 3;

[0054] The maintenance steps include:

[0055] Ensure that the booster hydraulic cylinder 4 has a retracted signal, and ensure that the pin hydraulic cylinder 10 has an extended signal;

[0056] Open the stop valve 91;

[0057] The triggering steps include:

[0058] Start hydraulic pump 3;

[0059] Control the third directional control valve to energize and reverse the direction to retract the pin hydraulic cylinder 10 into place;

[0060] Controlling the second directional control valve 41 to be energized and commutated will push the piston rod of the booster hydraulic cylinder 4 to drive the pull rod 7 of the ejection hydraulic cylinder 1, so that the ejection piston 6 slides away from the oil delivery hole 13;

[0061] The ejection steps include:

[0062] Making the oil in the accumulator 5 enter the rod chamber of the ejection hydraulic cylinder 1 through the oil delivery hole 13, and making the ejection piston 6 drive the pull rod 7 to accelerate and retract.

[0063] In this embodiment, dividing the working steps of the control method into an energy storage step, a holding step, a triggering step, and an ejection step can achieve fast and reliable ejection, reduce the possible pipeline pressure loss, and the risks brought by the commutation valve commutation delay timeout, jamming, etc.

[0064] In an embodiment of the present invention, the energy storage step further includes:

[0065] Detecting whether the booster hydraulic cylinder 4 has retracted in place. If not, controlling the second directional control valve 41 to be energized and commutated to retract the booster hydraulic cylinder 4 in place;

[0066] Detecting whether the pin hydraulic cylinder 10 has extended in place. If not, controlling the third directional control valve to be energized and commutated to extend the pin hydraulic cylinder 10 in place;

[0067] In this embodiment, the safety of the launching process can be ensured, and the occurrence of abnormal triggering situations can be prevented.

[0068] In an embodiment of the present invention, the holding step further includes:

[0069] After opening the stop valve 91, detecting whether the pressures of the first pressure sensor 92 and the second pressure sensor 17 are within the set threshold range. If not, controlling the first directional control valve 81 to be energized and commutated to replenish the pressure of the accumulator 5.

[0070] In this embodiment, the pressure of the accumulator 5 can be ensured to be stable within the set pressure threshold range, improving the reliability of the ejection hydraulic system.

[0071] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", 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 of the present invention.

[0072] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected to", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise clearly and specifically limited.

[0074] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and simple improvements made to the substantial content of the present invention shall be included within the protection scope of the present invention.

Claims

1. An ejection hydraulic system, characterized in that, Including: A catapult hydraulic cylinder (1), an oil tank (2), a hydraulic pump (3), an assisting hydraulic cylinder (4) and an accumulator (5). A catapult piston (6) and a pull rod (7) are arranged inside the catapult hydraulic cylinder (1); one end of the catapult hydraulic cylinder (1) is closed and the other end is open; the catapult hydraulic cylinder (1) is provided with an end cover (11) for closing its opening, a vent hole (12) is arranged on the outer peripheral wall of the catapult hydraulic cylinder (1) at the closed end, and an oil delivery hole (13) is arranged on the outer peripheral wall of the catapult hydraulic cylinder (1) at the open end; one end of the pull rod (7) is fixedly connected with the catapult piston (6), and the other end of the pull rod (7) passes through the end cover (11); the oil tank (2) is connected with the hydraulic pump (3), the hydraulic pump (3) is connected with the accumulator (5) through a first oil pipe (8), and a first direction control valve (81) is arranged on the first oil pipe (8); one end of the first oil pipe (8) between the first direction control valve (81) and the accumulator (5) is connected with one end of a second oil pipe (9), the other end of the second oil pipe (9) is connected with the oil delivery hole (13) of the catapult hydraulic cylinder (1), and a stop valve (91) is arranged on the second oil pipe (9); when the catapult piston (6) abuts against the end cover (11), the catapult piston (6) blocks the oil delivery hole (13) of the catapult hydraulic cylinder (1); the assisting hydraulic cylinder (4) is respectively connected with the hydraulic pump (3) and the oil tank (2) through a second direction control valve (41), and the piston rod in the assisting hydraulic cylinder (4) abuts against the pull rod (7).

2. The ejection hydraulic system according to claim 1, characterized in that, A pre-pressure oil circuit (14) is arranged in the inner wall of the catapult hydraulic cylinder (1). The first port of the pre-pressure oil circuit (14) is communicated with the pore wall of the oil delivery hole (13), the second port of the pre-pressure oil circuit (14) is communicated with the inner peripheral wall of the catapult hydraulic cylinder (1), and the second port of the pre-pressure oil circuit (14) is located below the oil delivery hole (13).

3. The ejection hydraulic system according to claim 1, characterized in that, A transition groove (15) is arranged on the inner peripheral wall of the catapult hydraulic cylinder (1) along its circumferential direction. The notch of the transition groove (15) is smoothly transitioned with the inner peripheral wall of the catapult hydraulic cylinder (1) through an arc surface (16), and one port of the oil delivery hole (13) is communicated with the bottom of the transition groove (15).

4. The ejection hydraulic system according to claim 1, characterized in that, First flanges (61) and second flanges (62) which are in sliding seal fit with the inner peripheral wall of the catapult hydraulic cylinder (1) are arranged at both ends of the catapult piston (6). A pressure-bearing groove (63) is formed between the first flanges (61) and the second flanges (62). When the first flanges (61) abut against the end cover (11), the pressure-bearing groove (63) is aligned with the oil delivery hole (13).

5. The ejection hydraulic system according to claim 1, characterized in that, Also included is a pin hydraulic cylinder (10). The pin hydraulic cylinder (10) is respectively connected with the hydraulic pump (3) and the oil tank (2) through a third direction control valve (101). The piston rod of the pin hydraulic cylinder (10) is connected with the pull rod (7) or the catapult mechanism and is used for maintaining the initial position of the pull rod (7) or the catapult mechanism.

6. The ejection hydraulic system according to claim 5, characterized in that, A check valve (82) is arranged on the first oil pipe (8) between the hydraulic pump (3) and the first direction control valve (81).

7. The ejection hydraulic system according to claim 6, characterized in that, A first pressure sensor (92) is provided on the second oil pipe (9) between the accumulator (5) and the stop valve (91), and a second pressure sensor (17) is provided on the end cover (11) of the ejection hydraulic cylinder (1).

8. The ejection hydraulic system according to claim 6, characterized in that, It also includes a third oil pipe (18), one end of which is connected to the rod chamber of the ejection hydraulic cylinder (1) through an end cover (11), and the other end of which is connected to the oil tank (2). A throttle valve (181) is provided on the third oil pipe (18).

9. A control method for an ejection hydraulic system, applied to the ejection hydraulic system according to any one of claims 1 to 5, characterized in that, The control method comprises: a charging step, a maintaining step, a triggering step and an ejection step; The charging step comprises: The piston in the ejection hydraulic cylinder (1) is pressed against the end cover (11) so that the ejection piston (6) is blocked at the oil delivery hole (13); Close the stop valve (91) and start the hydraulic pump (3); Controlling the first directional control valve (81) to switch on and off, thereby charging the accumulator (5); when the pressure in the accumulator (5) reaches a predetermined value, controlling the first directional control valve (81) to switch off and off, thereby placing the accumulator (5) and the hydraulic pump (3) in a disconnected state, thereby shutting down the hydraulic pump (3); The maintaining step comprises: Ensure that the booster hydraulic cylinder (4) has a retracted signal, and ensure that the pin hydraulic cylinder (10) has an extended signal; Open the stop valve (91); The triggering step includes: Starting the hydraulic pump (3); Controlling the third directional control valve to switch on power and retract the pin hydraulic cylinder (10) into position; Controlling the second directional control valve (41) to switch on electricity so that the piston rod of the booster hydraulic cylinder (4) pushes the pull rod (7) of the ejection hydraulic cylinder (1), causing the ejection piston (6) to slide away from the oil delivery hole (13); The ejection step comprises: The oil in the accumulator (5) enters the rod chamber of the ejection hydraulic cylinder (1) through the oil delivery hole (13), and the ejection piston (6) drives the pull rod (7) to be retracted at an accelerated speed.

10. The control method for an ejection hydraulic system according to claim 9, characterized in that, The charging step also includes: Detecting whether the booster hydraulic cylinder (4) is retracted into position, and if not, controlling the second directional control valve (41) to be energized and switched to retract the booster hydraulic cylinder (4) into position; Detecting whether the pin hydraulic cylinder (10) is extended to the proper position, and if not, controlling the third directional control valve to be energized and switched to extend the pin hydraulic cylinder (10) to the proper position; The maintaining step further comprises: After the stop valve (91) is opened, it is detected whether the pressure of the first pressure sensor (92) and the second pressure sensor (17) is within a set threshold range. If not, the first directional control valve (81) is controlled to be energized and switched to replenish pressure to the accumulator (5).

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