Overflow valve for pressurized delivery system of carrier rocket and pre-pressing assembly method of overflow valve

Abstract

The invention provides an overflow valve for a pressurized delivery system of a carrier rocket and a pre-pressing assembly method of the overflow valve, and relates to the technical field of fluid working systems, the overflow valve comprises a piston, a forcing cavity, a piston rod, a corrugated pipe and a main valve shell; the corrugated pipe is installed in the main valve shell, a forced cavity is formed in the main valve shell, and the forced cavity is located in the corrugated pipe; the piston rod and the piston are connected to form a combined body; the combined body is arranged on the corrugated pipe and the forced cavity; the valve seat part of the main valve shell is provided with an annular protrusion structure, the non-metal surface of the piston is provided with an annular groove, and the annular protrusion and the annular groove are in contact connection to form a spigot sealing structure. The piston rod is in clearance fit with the main valve shell to form a guide pair. According to the overflow valve, after a rocket is recycled, high-pressure gas is used, the valve is forcibly opened through the forcing cavity, and safe release of residual pressurized propellants in a rocket storage tank is completed.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid working systems, and in particular, to a relief valve for a booster and delivery system of a launch vehicle and a pre-pressurization assembly method thereof, especially a relief valve for a booster and delivery system of a reusable launch vehicle and a pre-pressurization assembly method thereof, and in particular, a large-caliber relief valve for a reusable cryogenic launch vehicle booster and delivery system and a pre-pressurization assembly method thereof. Background Art

[0002] With the continuous development of my country's aerospace industry, ultra-low temperature propellants represented by liquid hydrogen and liquid oxygen are widely used, and the demand for large-caliber ultra-low temperature valves is growing. Cryogenic relief valves are widely used in the pressurized delivery system of cryogenic rockets. The working principle is that when the pressure of the rocket propellant tank exceeds the design value, the relief valve opens to achieve pressure relief and ensure the safety of the tank. When the tank pressure is lower than the set value, the relief valve closes and seals to prevent leakage of cryogenic propellant. For reusable launch vehicles, it is necessary to safely release the pressurized residual propellant inside the tank after the rocket is recovered. However, the pressure of this part of the propellant is usually lower than the design value of the opening pressure of the relief valve. Therefore, traditional relief valves cannot meet the demand for low-pressure propellant release. In addition, the reusability of the valve requires the relief valve to have better sealing performance at low temperatures. Therefore, the vigorous development of reusable launch vehicles has put forward new requirements for large-caliber relief valves that can actively release at low pressure, have high reliability sealing, and have a long low-temperature life.

[0003] The large-caliber cryogenic relief valve for launch vehicles has the characteristics of complex product structure, numerous assembly procedures, and harsh service conditions. The ultra-low temperature valves produced by traditional assembly methods are difficult to debug, and under extreme working conditions, the product sealing is difficult to meet the requirements. The core reason is that during the assembly process of the relief valve, due to the difficulty in ensuring the processing accuracy of large-sized installed parts and the difficulty in uniform force during the assembly process, the metal / non-metallic sealing pair of the valve cannot be fully engaged to form an effective line seal after assembly, resulting in local leakage and sealing failure. As a result, the pressure of the rocket propellant tank is low during the launch mission, and the propellant flow and rocket thrust are insufficient, which ultimately leads to the failure of the rocket launch.

[0004] The assembly and debugging process of the relief valve is complicated and involves many assembly steps. If leakage occurs, the valve needs to be disassembled, the sealing components replaced, and reassembled and debugged. This results in poor assembly quality stability, low production efficiency, and insufficient batch qualification rate for large-caliber relief valves, which leads to repetitive labor and long repair time, making it difficult to meet the growing needs of aerospace missions. Summary of the invention

[0005] In view of the defects in the prior art, the object of the present invention is to provide a relief valve for a booster delivery system of a launch vehicle and a pre-pressurization assembly method thereof.

[0006] According to the present invention, a relief valve for a booster delivery system of a launch vehicle comprises: a piston, a forced chamber, a piston rod, a bellows and a main valve housing; The bellows is installed in the main valve housing, the main valve housing is provided with the forced cavity, the forced cavity is located in the bellows, and the wall of the forced cavity is connected to the piston rod through a thread; The piston rod and the piston are connected to form a combination, and the combination is installed on the bellows and the forced chamber, and can fully open the main valve by introducing compressed air into the forced chamber; The valve seat portion of the main valve housing is provided with an annular protrusion structure, the non-metal surface of the piston is provided with an annular groove, and the annular protrusion and the annular groove are in contact and connected to form a stop seal structure; The piston rod and the main valve housing are clearance-matched to form a guide pair.

[0007] Preferably, the depth of the annular groove is 0.1 mm-0.15 mm; The annular protrusion is an arc-shaped chamfer, and the diameter of the arc-shaped chamfer is 0.2mm-0.4mm.

[0008] Preferably, the unilateral matching clearance between the piston rod and the main valve housing is 0.01mm-0.1mm; The ratio of the guide surface length to the guide diameter of the piston rod is not less than 1.5.

[0009] Preferably, it also includes: a pre-pressing forming tool and a clock-type dial indicator; The pre-pressing forming tool can be installed on the main valve housing and pre-press the piston to generate an indentation on the non-metal surface where the piston contacts the annular protrusion, and the indentation forms the annular groove; The bell-type dial gauge is used to measure the pressing depth of the piston end surface of the piston and the depth of the indentation; After the pre-pressing is completed, the pre-pressing forming tool can be removed from the main valve housing.

[0010] Preferably, the pre-pressing forming tooling comprises: an adjusting screw, a centering screw cover and a stopper; The adjusting screw is threadedly connected to the centering screw cover, and the stopper is detachably arranged at one end of the adjusting screw; The centering screw cover and the stopper are used to be installed in the forced cavity; When the adjusting screw is rotated on the centering screw cover, the adjusting screw can drive the stopper to move in the forced cavity, and the stopper drives the assembly to pre-press the non-metallic surface of the piston.

[0011] Preferably, one end of the adjusting screw is provided with a lower end spherical surface; An inner conical surface matching the lower end spherical surface is arranged at the center of the stopper.

[0012] Preferably, the outer surface of the centering screw cover is provided with an external thread that matches the internal thread of the forcing chamber; An internal thread matching the external thread of the adjusting screw is arranged on the inner surface of the centering screw cover.

[0013] Preferably, the outer surface of the centering nut used is also provided with a knurled surface and a backing groove.

[0014] The present invention also provides a pre-pressurization assembly method of a relief valve, which is used for the above-mentioned relief valve used in the booster delivery system of a launch vehicle, and specifically comprises the following steps: Step S1: Assembling the main valve of the relief valve; Step S2: selecting a matching centering screw cap and stopper according to the thread size on the forced cavity of the relief valve; Step S3: The centering nut cover and the stopper are sequentially installed into the forced cavity from top to bottom, and the stopper contacts the piston rod, the centering nut cover is fixed in the forced cavity, and the stopper can move in the forced cavity; Step S4: screw the adjusting screw into the centering screw cover, and move the adjusting screw downward so that the spherical surface at the lower end of the adjusting screw contacts the center position of the stopper; Step S5: rotating the adjusting screw to move it downward, so that the non-metallic surface on the piston and the annular protrusion are pre-pressed. During the pre-pressing process, the piston end face of the piston is pressed from the outlet of the main valve housing of the relief valve by the dial gauge push rod of the bell dial gauge, and the downward pressing depth of the piston end face is measured to determine the downward displacement distance of the adjusting screw; Step S6: When the downward displacement distance of the adjusting screw reaches a preset value, the adjusting screw is kept stationary, and the pre-pressure is maintained for a preset time, so that a complete indentation is formed on the non-metallic surface of the piston; Step S7: rotating the adjusting screw rod to move it upward until the spherical surface at the lower end of the adjusting screw rod and the stopper are no longer subjected to force; Step S8: measuring again by the bell-type dial indicator to determine whether the depth of the indentation is the preset value, if so, completing the pre-pressing, if not, moving the adjustment screw downward again to perform pre-pressing until the depth of the indentation is the preset value; Step S9: screw the adjusting screw, the centering screw cap, and the stopper out of the forced cavity, take out the pre-pressing forming tooling, continue to assemble the valve body of the relief valve, and determine the torque; Step S10: Debugging and checking the air tightness of the overflow valve.

[0015] Preferably, the step S1 specifically comprises the following steps: Step S1.1: Connect the piston and the piston rod through threads, and install the bellows and the forced chamber to form an integral structure; Step S1.2: Install the whole structure into the main valve housing. Before installation, use a lifting tool to support the piston end face of the piston to prevent the non-metallic surface on the piston from being crushed by the stop on the main valve housing during the installation process.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention arranges a forced cavity structure inside the bellows and introduces a certain pressure of gas into the forced cavity, so that the overflow valve can be actively opened when the pressure is lower than the designed opening pressure, thereby realizing the discharge of low-pressure residual propellant of the repeatable rocket.

[0017] 2. The pre-pressing forming process of the present invention is to pre-press the non-metallic surface on the piston with the help of pre-pressing forming tooling to form a stop seal structure, and measure the depth of the pre-pressing indentation by a bell-type dial indicator. This method gets rid of the risk of product disassembly and replacement of parts, and solves the problem of low one-time qualified rate in assembly and debugging of large-caliber relief valves at a relatively low cost, reduces the scrap rate of parts, and improves the low-temperature sealing performance and operating life of the relief valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 It is a schematic structural diagram of the overflow valve and pre-pressing forming tooling for the booster delivery system of a carrier rocket of the present invention; Figure 2 It is a structural schematic diagram of a pre-pressing and forming tool for a relief valve of a booster delivery system of a launch vehicle according to the present invention; Figure 3 It is a schematic diagram of the assembly relationship of the pre-pressing forming tooling for the overflow valve of the boosting and conveying system of a carrier rocket according to the present invention; Figure 4 It is a schematic diagram of the pre-pressing and measuring of the pre-pressing forming tooling of the overflow valve for the boosting and conveying system of a launch vehicle according to the present invention on the valve body; Figure 5 It is a schematic diagram of the pre-pressing depth of the pre-pressing forming tool for the overflow valve of the boosting and conveying system of a carrier rocket according to the present invention; Figure 6 It is a schematic diagram of the complete indentation of the pre-pressing forming tooling of the overflow valve of the boost delivery system of a launch vehicle after pre-pressing.

[0019] The figure shows: Adjusting screw 1, lower end spherical surface 101, centering screw cover 2, stopper 3, inner cone 301, bell-type dial indicator 4, dial indicator push rod 5, piston end face 6, main valve housing outlet 7, stop seal structure 8, piston 9, non-metallic surface 901, forced chamber 10, piston rod 11, bellows 12, main valve housing 13, back pressure chamber 14, back pressure chamber screw cover thread 15. DETAILED DESCRIPTION

[0020] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0021] Embodiment 1: like Figure 1-Figure 6 As shown, this embodiment provides a relief valve for a booster delivery system of a launch vehicle, comprising: a piston 9, a forced chamber 10, a piston rod 11, a bellows 12 and a main valve housing 13; the bellows 12 is installed in the main valve housing 13, and a forced chamber 10 is provided on the main valve housing 13, and the forced chamber 10 is located in the bellows 12, and the wall surface of the forced chamber 10 is fixedly connected with the piston rod 11 through a thread; the piston rod 11 and the piston 9 are connected to form a combination, and the combination is installed on the bellows 12 and the forced chamber 10, and the main valve can be fully opened by introducing compressed air into the forced chamber 10; the valve seat portion of the main valve housing 13 is provided with an annular protrusion structure, and the non-metallic surface of the piston 9 is provided with an annular groove, and the annular protrusion and the annular groove are in contact and connected to form a stop seal structure 8; the piston rod 11 and the main valve housing 13 are clearance-matched to form a guide pair.

[0022] The depth of the annular groove is 0.1mm-0.15mm; the annular protrusion is an arc chamfer, and the diameter of the arc chamfer is 0.2mm-0.4mm. The single-side matching clearance between the piston rod 11 and the main valve housing 13 is 0.01mm-0.1mm; the ratio of the guide surface length to the guide diameter of the piston rod 11 is not less than 1.5.

[0023] The relief valve also includes: a pre-pressing tool and a bell-type dial indicator 4; the pre-pressing tool can be installed on the main valve housing 13, and pre-press the piston 9, so that an indentation is generated on the non-metallic surface 901 where the piston 9 contacts the annular protrusion, and the indentation forms an annular groove; the bell-type dial indicator 4 is used to measure the downward pressure depth of the piston end face 6 of the piston 9 and the depth of the indentation; after the pre-pressing is completed, the pre-pressing tool can be removed from the main valve housing 13.

[0024] The pre-pressing forming tooling includes: an adjusting screw 1, a centering screw cap 2 and a stopper 3; the adjusting screw 1 is threadedly connected to the centering screw cap 2, and the stopper 3 is detachably arranged at one end of the adjusting screw 1; the centering screw cap 2 and the stopper 3 are used to be installed in the forced cavity 10; when the adjusting screw 1 rotates on the centering screw cap 2, the adjusting screw 1 can drive the stopper 3 to move in the forced cavity 10, and the stopper 3 drives the assembly, thereby pre-pressing the non-metallic surface of the piston 9. A lower end spherical surface 101 is provided at one end of the adjusting screw 1; an inner conical surface 301 adapted to the lower end spherical surface is provided at the center position of the stopper 3. An outer thread adapted to the inner thread of the forced cavity 10 is provided on the outer surface of the centering screw cap 2; an inner thread adapted to the outer thread of the adjusting screw 1 is provided on the inner surface of the centering screw cap 2. The outer surface of the centering screw cap 2 is also provided with a knurled surface and a backing groove.

[0025] The overflow valve of this embodiment can use high-pressure gas to force the valve to open through the forcing chamber after the rocket is recovered, thereby completing the safe discharge of the residual pressurized propellant in the rocket tank.

[0026] The pre-pressed forming structure of this embodiment can effectively improve the sealing performance and operating life of the overflow valve at low temperatures, and meet the requirements of reusability.

[0027] The relief valve of this embodiment has a forced opening function. When the tank pressure is lower than the design value of the relief valve, the existing relief valve cannot be opened and the tank pressure cannot be released. However, the present application can force the valve to open by introducing compressed gas into the forced chamber of the relief valve, thereby achieving pressure release under low pressure.

[0028] Existing overflow valves have the defect of insufficient low-temperature sealing effect, low pass rate, and lack the ability to actively open and release under low pressure. In addition, similar cryogenic valves of NASA in the United States use a large amount of precision / ultra-precision processing technology to ensure the sealing reliability under low temperature, which is very costly.

[0029] This embodiment also provides a pre-pressurization assembly method of a relief valve, wherein the relief valve used in a booster delivery system of a launch vehicle specifically comprises the following steps: Step S1: Assemble the main valve of the overflow valve; specifically, it includes the following steps: Step S1.1: Connect the piston 9 and the piston rod 11 by threads, and install the bellows 12 and the forced chamber 10 to form an integral structure; Step S1.2: Install the whole structure into the main valve housing 13. Before installation, use a lifting tool to support the piston end face 6 of the piston 9 to prevent the non-metallic surface of the piston 9 from being crushed by the stopper on the main valve housing 13 during the installation process; Step S2: selecting a matching centering screw cap 2 and stopper 3 according to the thread size on the forced cavity 10 of the relief valve; Step S3: The centering nut 2 and the stopper 3 are sequentially installed into the forced cavity 10 from top to bottom, and the stopper 3 is in contact with the piston rod 11, the centering nut 2 is fixed in the forced cavity 10, and the stopper 3 can move in the forced cavity 10; Step S4: screw the adjusting screw 1 into the centering screw cover 2, and move the adjusting screw 1 downward so that the spherical surface of the lower end of the adjusting screw 1 abuts against the center position of the stopper 3; Step S5: rotating the adjusting screw 1 to make it move downward, so that the non-metallic surface on the piston 9 and the annular protrusion are pre-pressed. During the pre-pressing process, the dial gauge push rod 5 of the bell dial gauge 4 pushes against the piston end face 6 of the piston 9 from the outlet 7 of the main valve housing of the relief valve, and the downward pressing depth of the piston end face 6 is measured to determine the downward displacement distance of the adjusting screw 1; Step S6: When the downward displacement distance of the adjusting screw 1 reaches a preset value, the adjusting screw 1 is kept stationary, and the pre-pressure is maintained for a preset time, so that a complete indentation is formed on the non-metallic surface of the piston 9; Step S7: rotating the adjusting screw 1 to move it upward until the spherical surface at the lower end of the adjusting screw 1 and the stopper 3 are no longer subjected to force; Step S8: Measure again with the bell dial gauge 4 to determine whether the depth of the indentation is the preset value. If so, pre-pressing is completed. If not, the adjustment screw 1 is moved down again to perform pre-pressing until the depth of the indentation is the preset value. Step S9: screw the adjusting screw 1, the centering screw cap 2, and the stopper 3 out of the forced cavity 10, take out the pre-pressing forming tooling, continue to assemble the valve body of the relief valve, and determine the torque; Step S10: Debugging and checking the air tightness of the overflow valve.

[0030] Embodiment 2: Those skilled in the art may understand this embodiment as a more specific description of Embodiment 1.

[0031] This embodiment provides a main valve of a general-purpose aerospace large-caliber relief valve and a pre-pressing assembly method thereof. The main valve includes: a main valve housing 13, a bellows 12, a piston 9, a piston rod 11, etc.

[0032] The piston 9, piston rod 11 and bellows 12 are in the main valve housing 13. The valve seat portion of the main valve housing has an annular protrusion structure, and the non-metallic surface of the piston has an annular groove. The annular protrusion and the annular groove are approximately conformal, forming a stop seal structure 8. The piston rod and the housing are clearance-matched to form a guide pair, and the single-side clearance is within a specific range. The length of the piston rod guide surface and the guide diameter are not less than specific values.

[0033] The pre-pressing assembly method mainly includes the assembly process of the main valve and the pre-pressing forming process. The main valve assembly process is to install the piston 9 and the piston rod 11 into the bellows 12 and the forced chamber 10 through threaded connection, and then install the whole into the main valve housing 13. Before installation, a lifting tool is required to support the end face of the piston 9 to prevent the non-metal on the piston 9 from being crushed by the stop on the main valve housing 13 during the installation process. The pre-pressing forming process is to use a pre-pressing forming tool to pre-press the non-metal on the piston 9, so as to machine an annular groove on the surface of the non-metallic sealing surface, and measure the pre-pressing depth by a bell-type dial indicator.

[0034] The stop seal structure described herein has a non-metallic annular groove with a depth of 0.1-0.15 mm, and the annular metal protrusion structure is processed into an arc-shaped chamfer with a chamfer diameter of 0.2-0.4 mm. The annular groove is approximately conformal to the annular protrusion profile, and the annular groove and the annular protrusion are in line contact and seal at the bottom of the annular groove. The annular groove has a guiding function during the assembly of the relief valve, guiding the annular protrusion to slide into the annular groove to form an effective stop seal.

[0035] The piston rod and the housing are clearance matched, and the single-side clearance is 0.01-0.1 mm. The ratio of the piston rod guide surface length to the guide diameter is not less than 1.5.

[0036] This embodiment also provides a pre-pressing assembly method for a general-purpose aerospace large-diameter relief valve, wherein the outer surface of the tooling centering screw cover used has a knurled surface, a back cutter groove, an external thread, and an internal thread that matches the external thread of the adjusting screw.

[0037] The surface of the tooling adjustment screw used is an external thread, one end is an external hexagon, and the other end is a spherical surface.

[0038] The tooling stopper used is cylindrical, with a flat surface at one end and an inner conical surface at the other end.

[0039] The main valve pre-compression assembly method for a general-purpose aerospace large-caliber relief valve comprises the following steps: S1. Select the matching centering screw cap and stopper according to the thread size on the back pressure chamber of the relief valve main valve; S2. When the adjustment screw is rotated clockwise and moved downward, the preload depth needs to be measured with a clock-type dial indicator.

[0040] Embodiment 3: Those skilled in the art may understand this embodiment as a more specific description of Embodiment 1.

[0041] The present embodiment relates to the field of valve fluid working systems, and in particular to large-caliber valves suitable for new generation launch vehicles. The present embodiment provides a relief valve for cryogenic rockets and a pre-pressure sealing method thereof.

[0042] A cryogenic rocket relief valve provided in this embodiment includes: a main valve housing 13, a bellows 12, a piston 9, a piston rod 11, etc. The piston 9, the piston rod 11, and the bellows 12 are inside the main valve housing 13. There is an annular protrusion structure on the valve seat portion of the main valve housing, and there is an annular groove on the non-metallic surface of the piston. The annular protrusion and the annular groove are approximately conformal to form a stop sealing structure 8. The piston rod and the housing are clearance-matched to form a guide pair, and the single-sided clearance is within a specific range. The guide surface length and guide diameter of the piston rod are not less than specific values.

[0043] This embodiment also provides an assembly method of a large-caliber relief valve, which mainly includes: With the slot on the end face of the piston 9 as the counter torque, the piston rod 11 is connected to the piston 9 by threads and a certain torque is applied to install it on the bellows 12 and the forced chamber 10 to form a component A. The component A is installed on the main valve housing 13 by bolt connection. Before installation, a lifting tool is required to support the end face of the piston 9 to prevent the non-metal on the piston 9 from being crushed by the stop on the main valve housing 13 during the installation process.

[0044] A circular groove is machined on the non-metallic surface of the piston using a pre-pressing tooling, and the pre-pressing tooling includes an adjusting screw 1, a centering screw cover 2, and a stopper 3. The hexagonal surface at one end of the adjusting screw 1 is used as a clamping surface for applying rotational force. The inner thread of the centering screw cover 2 is adapted to the outer thread of the adjusting screw 1, and can be rotated up and down therein to ensure the center position. The outer thread of the centering screw cover 2 is adapted to the inner thread of the forced cavity 10 of the valve body. The size of the stopper 3 should be adapted to the inner hole diameter of the forced cavity 10 of the main valve and the piston rod 11. The spherical surface at one end of the adjusting screw 1 is adapted to the inner conical surface of the stopper 3 to ensure the center position. When the adjusting screw 1 rotates clockwise to apply force to the stopper 3, the stopper 3 is evenly stressed on the valve body.

[0045] This embodiment also provides a method for using a pre-pressing tool for a general-purpose aerospace large-caliber relief valve, comprising the following steps: According to the thread size on the forced cavity 10 of the relief valve main valve, select the matching centering screw cap and stopper. When the adjustment screw is rotated clockwise and moved downward to implement pre-pressure, the pre-pressure depth needs to be measured with a bell-type dial indicator.

[0046] The present embodiment provides a method for pre-pressing the main valve of a large-caliber aerospace general-purpose relief valve, which produces an indentation with controllable depth and high precision without affecting product performance. The pre-pressing method can pre-press the main valve sealing component of a general-purpose relief valve before commissioning to produce an optimal indentation, and the method prevents leakage at the sealing component of the valve in subsequent extreme working condition tests.

[0047] Embodiment 4: Those skilled in the art may understand this embodiment as a more specific description of Embodiment 1.

[0048] This embodiment provides a main valve for a general-purpose large-caliber relief valve for aerospace and a pre-pressing assembly method thereof. The main valve includes a piston, a piston rod, a bellows, and a housing. The piston and the housing together form a stop seal structure. The piston rod and the housing are clearance-matched to form a guide effect. The aspect ratio of the guide surface is not less than 1.5.

[0049] During the valve assembly process, the main valve outlet sealing surface is pre-pressurized, which has high efficiency, is safer and more convenient. It can prevent the valve from leaking and secondary damage to the parts during the valve disassembly and assembly process, and avoid repair after installation and testing.

[0050] This embodiment is suitable for implementation during the assembly and debugging of a large-caliber relief valve.

[0051] The specific assembly method is as follows: With the slot on the end face of the piston 9 as the counter torque, the piston rod 11 is connected to the piston 9 by threads and a certain torque is applied to install it on the bellows 12 and the forced chamber 10 to form a component A; Install component A into the main valve housing 13 through bolt connection. Before installation, use a lifting tool to support the end face of the piston 9 to prevent the non-metal on the piston 9 from being crushed by the stop on the main valve housing 13 during the installation process.

[0052] The non-metal on the piston 9 is pre-pressed to a certain depth using a pre-pressing tool.

[0053] The most preferred method for measuring the pre-pressing depth is to use a bell-type dial indicator to measure and control the pre-pressing depth, and to pre-press the piston 9 to different depths with the help of a pre-pressing forming tool.

[0054] Pre-pressed tooling structure, such as Figure 2 As shown, it is composed of an adjusting screw 1, a centering screw cover 2, and a stopper 3.

[0055] The hexagonal surface at one end of the adjusting screw 1 is used as a clamping surface for applying a rotational force; The inner thread of the centering screw cap 2 is adapted to the outer thread of the adjusting screw 1, and can be rotated up and down therein to ensure the center position; The external thread of the centering screw cap 2 is adapted to the internal thread of the forced cavity 10 of the main valve; The size of the stopper 3 should be adapted to the inner diameter of the main valve's forced cavity 10 and the piston rod 11, and the parallelism of the two end surfaces should be within 0.03mm; The spherical surface at one end of the adjusting screw 1 is adapted to the inner conical surface of the stopper 3 to ensure the center position; When the adjusting screw 1 rotates clockwise to apply force to the stopper 3, the stopper 3 is evenly applied force to the valve body.

[0056] S1. Select the matching centering screw cap and stopper according to the thread size on the back pressure chamber of the relief valve main valve; S2. When the adjustment screw is rotated clockwise and moved downward to implement preloading, the preloading depth needs to be measured with a clock-type dial indicator.

[0057] Step 1: Figure 1 As shown, the main valve assembly of the relief valve is completed.

[0058] Step 2: If Figure 1 As shown, install the tooling according to Figure 2 As described above, the adjusting screw 1, the centering screw cover 2, and the stopper 3 are adapted into the screw cover thread 15 of the back pressure chamber, and the lower end spherical surface of the adjusting screw 1 presses against the stopper 3 and ensures the center position.

[0059] The back pressure chamber 14 and the main valve inlet pressure are connected to the command valve through the pressure pipe. The command valve determines whether to open the main valve according to the difference between the main valve inlet pressure and the back pressure chamber pressure. The function of the forced chamber is to force the main valve to open after the compressed gas is introduced, ignoring the control of the command valve.

[0060] Step 3: If Figure 4 As shown, the tooling adjustment screw 1 is rotated to move downward, so that the non-metallic sealing material on the piston 9 and the stop seal structure 8 are pre-pressed.

[0061] Step 4: Figure 4 and Figure 5 As shown, during the pre-pressing process, the dial gauge push rod 5 of the bell-type dial gauge 4 presses against the piston end face 6 from the outlet 7 of the overflow valve main valve housing, and the pressing depth of the piston end face 6 is the pressing depth of the non-metallic sealing material.

[0062] Step 5: Figure 6 As shown, the non-metallic sealing surface and the stop sealing structure 8 are pre-pressed for a certain period of time to form a complete indentation.

[0063] Step 6: Move the rotating tool adjustment screw 1 upward until the lower end spherical surface of the adjustment screw 1 and the stopper 3 are no longer subjected to force.

[0064] Step 7: Figure 4 and Figure 5 As shown, the indentation is controlled at the optimal pre-pressing depth by measuring with a bell-type dial indicator again.

[0065] Step 8: Rotate the centering screw cap 2 counterclockwise to loosen the adjusting screw 1 from the back pressure chamber screw cap thread 15, then invert the main valve and slide the stopper 3 out. In this way, the adjusting screw 1, centering screw cap 2, and stopper 3 are screwed out of the back pressure chamber screw cap thread, and the main valve pre-compression tooling is taken out, and the relief valve body is assembled and the torque is determined.

[0066] Step 9: Debug the overflow valve and check its air tightness.

[0067] After comparing the qualified rate, cost, efficiency, delivery cycle and other aspects before and after the improvement of the assembly process method in this embodiment, it is found that after the improvement of the assembly process method, the qualified rate of the first assembly test is increased to 85%-90%, which reduces the production and development costs, saves about 66% ((90%-30%) / 90%=66%) of the production cost, greatly improves the production efficiency, saves about 70% of the production time ((17-5) / 17=70.6%), shortens the delivery cycle of the model product, and shortens the production cycle from 10-17 months to 3-5 months, ensuring the high-quality delivery of the overflow valve.

[0068] The present invention provides a main valve of a general-purpose large-caliber relief valve for aerospace and a pre-pressing assembly method thereof. The valve seat and the piston surface of the main valve are provided with a conformal stop seal structure, and the piston rod and the housing are gap-matched to form a guide pair, and the single-side matching gap is within a specific range. The length of the piston rod guide surface and the guide diameter are not less than a specific value. The pre-pressing assembly method mainly includes an assembly process and a pre-pressing forming process of the relief valve main valve. The main valve assembly is to install the piston 9 and the piston rod 11 into the bellows 12 and the forced chamber 10 through threaded connection, and then install the whole into the main valve housing 13. Before installation, a lifting tool is required to support the end face of the piston 9 to prevent the non-metal on the piston 9 from being crushed by the stop on the main valve housing 13 during the installation process. The pre-pressing forming process is to pre-press the non-metal on the piston 9 with the help of the pre-pressing forming tool to form a stop seal structure, and measure the depth of the pre-pressing indentation by a bell-type dial indicator. This method gets rid of the risk of product disassembly and replacement of parts, solves the problem of low one-time qualified rate of large-caliber relief valve assembly and commissioning, and reduces the scrap rate of parts.

[0069] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0070] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A relief valve for a booster delivery system of a launch vehicle, characterized in that: include: A piston (9), a forced chamber (10), a piston rod (11), a bellows (12) and a main valve housing (13); The bellows (12) is installed in the main valve housing (13); the main valve housing (13) is provided with the forced chamber (10); the forced chamber (10) is located in the bellows (12); and the wall surface of the forced chamber (10) is connected to the piston rod (11) via a thread; The piston rod (11) and the piston (9) are connected to form a combination, and the combination is installed on the bellows (12) and the forced chamber (10), and can fully open the main valve by introducing compressed air into the forced chamber (10); The valve seat portion of the main valve housing (13) is provided with an annular protrusion structure, the non-metallic surface of the piston (9) is provided with an annular groove, and the annular protrusion and the annular groove are in contact and connected to form a stop seal structure (8); The piston rod (11) and the main valve housing (13) are clearance-matched to form a guide pair.

2. The overflow valve for a launch vehicle booster delivery system according to claim 1, characterized in that: The depth of the annular groove is 0.1mm-0.15mm; The annular protrusion is an arc-shaped chamfer, and the diameter of the arc-shaped chamfer is 0.2mm-0.4mm.

3. The overflow valve for a launch vehicle booster delivery system according to claim 1, characterized in that: The single-side matching clearance between the piston rod (11) and the main valve housing (13) is 0.01 mm-0.1 mm; The ratio of the guide surface length to the guide diameter of the piston rod (11) is not less than 1.

5.

4. The relief valve for a launch vehicle booster delivery system according to claim 1, characterized in that: Also includes: Pre-pressing tooling and dial indicator (4); The pre-pressing forming tool can be installed on the main valve housing (13) and pre-press the piston (9) so that an indentation is generated on the non-metallic surface where the piston (9) contacts the annular protrusion, and the indentation forms the annular groove; The bell-type dial gauge (4) is used to measure the pressing depth of the piston end surface (6) of the piston (9) and the depth of the indentation; After the pre-pressing is completed, the pre-pressing forming tool can be removed from the main valve housing (13).

5. The overflow valve for a launch vehicle booster delivery system according to claim 4, characterized in that: The pre-pressing tooling comprises: an adjusting screw (1), a centering screw cover (2) and a stopper (3); The adjusting screw (1) is threadedly connected to the centering screw cover (2), and the stopper (3) is detachably arranged at one end of the adjusting screw (1); The centering screw cover (2) and the stopper (3) are used to be installed in the forced cavity (10); When the adjusting screw (1) rotates on the centering screw cover (2), the adjusting screw (1) can drive the stopper (3) to move in the forced cavity (10), and the stopper (3) drives the assembly, thereby pre-pressing the non-metallic surface of the piston (9).

6. The overflow valve for a launch vehicle booster delivery system according to claim 5, characterized in that: One end of the adjusting screw (1) is provided with a lower end spherical surface; An inner conical surface adapted to the lower end spherical surface is provided at the center of the stopper (3).

7. The relief valve for a launch vehicle booster delivery system according to claim 5, characterized in that: The outer surface of the centering screw cover (2) is provided with an external thread that matches the internal thread of the forcing chamber (10); An internal thread matching the external thread of the adjusting screw rod (1) is provided on the inner surface of the centering screw cover (2).

8. The relief valve for a launch vehicle booster delivery system according to claim 7, characterized in that: The outer surface of the centering screw cover (2) is also provided with a knurled surface and a backing groove.

9. A method for pre-pressing an overflow valve, characterized in that: The overflow valve for the booster delivery system of a launch vehicle according to claim 5 specifically comprises the following steps: Step S1: Assembling the main valve of the relief valve; Step S2: Selecting a matching centering screw cap (2) and a stopper (3) according to the size of the thread on the forced cavity (10) of the relief valve; Step S3: The centering nut cover (2) and the stopper (3) are sequentially installed into the forced chamber (10) from top to bottom, and the stopper (3) is brought into contact with the piston rod (11), so that the centering nut cover (2) is fixed in the forced chamber (10) and the stopper (3) can move in the forced chamber (10); Step S4: screw the adjusting screw (1) into the centering screw cover (2), and move the adjusting screw (1) downward so that the spherical surface at the lower end of the adjusting screw (1) abuts against the center position of the stopper (3); Step S5: rotating the adjusting screw (1) to move it downward, so that the non-metallic surface on the piston (9) and the annular protrusion are pre-pressed. During the pre-pressing process, the dial gauge push rod (5) of the clock-type dial gauge (4) pushes against the piston end face (6) of the piston (9) from the outlet (7) of the main valve housing of the overflow valve, and the downward pressure depth of the piston end face (6) is measured to determine the downward displacement distance of the adjusting screw (1); Step S6: when the downward displacement distance of the adjusting screw (1) reaches a preset value, the adjusting screw (1) is kept stationary, and the pre-pressure is maintained for a preset time, so that a complete indentation is formed on the non-metallic surface of the piston (9); Step S7: rotating the adjusting screw (1) to move it upward until the spherical surface at the lower end of the adjusting screw (1) and the stopper (3) are no longer subjected to force; Step S8: measuring again with the bell-type dial indicator (4) to determine whether the depth of the indentation is the preset value. If so, pre-pressing is completed. If not, the adjusting screw (1) is moved down again to perform pre-pressing until the depth of the indentation is the preset value. Step S9: screw the adjusting screw (1), the centering screw cover (2), and the stopper (3) out of the forced cavity (10), remove the pre-pressing forming tooling, continue to assemble the valve body of the relief valve, and determine the torque; Step S10: Debugging and checking the air tightness of the overflow valve.

10. The pre-compression assembly method of the relief valve according to claim 9, characterized in that: The step S1 specifically includes the following steps: Step S1.1: The piston (9) and the piston rod (11) are connected by threads, and the bellows (12) and the forced chamber (10) are installed to form an integral structure; Step S1.2: Install the whole structure into the main valve housing (13). Before installation, use a lifting tool to support the piston end face (6) of the piston (9) to prevent the non-metallic surface of the piston (9) from being crushed by the stopper on the main valve housing (13) during the installation process.

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