Pressure accumulator diaphragm capsule vibration tool and regulation and control method thereof

Abstract

The invention provides a pressure accumulator diaphragm capsule vibration tool and a regulation and control method thereof. The tool comprises a tool upper cover, a tool lower base, a heat insulation plate and an adapter plate. The adapter plate is fixed on the vibration table surface; the tool lower base, the thermal insulation plate and the adapter plate are fixedly connected; a pressure accumulator diaphragm capsule is placed in the tool lower base; the tool upper cover is fixedly connected to the top of the tool lower base, and an independent cavity is formed between the inner wall of the tool upper cover and the pressure accumulator diaphragm capsule so as to provide a low-temperature vibration environment. A liquid nitrogen inlet, a liquid nitrogen outlet and a nitrogen outlet are formed in the tool upper cover; and the liquid nitrogen inlet, the liquid nitrogen outlet and the nitrogen outlet are respectively connected with a liquid nitrogen inlet pipeline, a liquid nitrogen return pipeline and a nitrogen discharge pipeline. The tool is simple in structure, accurate pressure window control can be achieved, the continuous circulating liquid supplementing function in the low-temperature vibration process is achieved, the tool can achieve large-amplitude vibration loading on a small-tonnage vibration table top by optimizing a force transmission path and reducing the dead weight of a system, and the test controllability and the test efficiency are improved.

Description

Technical Field

[0001] This application relates to the field of accumulator technology for liquid rocket delivery pipelines, and in particular to an accumulator diaphragm vibration fixture and its control method. Background Technology

[0002] In liquid rocket propulsion systems, accumulators are typically installed at the propellant line inlet to suppress and reduce POGO vibrations in the rocket's longitudinal direction and water hammer caused by the instantaneous opening and closing of valves. The diaphragm, as the core elastic element of the accumulator in responding to pressure fluctuations in the pipeline under cryogenic pressure conditions, directly affects the overall performance and reliability of the accumulator. Therefore, ground tests often require simulating flight conditions to verify the cryogenic vibration performance of the accumulator diaphragm.

[0003] The existing patent publication number CN104897493A discloses a method and system for low-temperature pressure cycle life testing, which can apply pulsating vibration loading to the diaphragm in a low-temperature environment. However, the transmission mechanism between the moving coil and the diaphragm in this scheme is complex. In actual tests, the diaphragm is placed in liquid nitrogen medium, and the vibration magnitude is easily amplified due to the transmission coupling, causing the test loading conditions to deviate from the actual flight conditions, and even causing damage to the diaphragm.

[0004] Another patent, CN103674458A, proposes a liquid nitrogen temperature zone vibration test device for cryogenic accumulators in launch vehicles. By constructing a pressurized gas supply system, it achieves vibration testing of the entire accumulator under cryogenic conditions. However, this scheme uses a one-time liquid nitrogen filling method and lacks a liquid replenishment and pressure control mechanism, which easily leads to air trapping areas on both sides of the diaphragm, causing structural instability or damage to the diaphragm during vibration. Furthermore, under this condition, the diaphragm is located in a high static pressure liquid nitrogen environment, which differs significantly from the low-temperature, low-pressure atmosphere of the accumulator diaphragm during actual flight, affecting the engineering equivalence of the test results.

[0005] Therefore, the urgent technical problems to be solved are: during the low-temperature vibration test of the accumulator diaphragm, the main vibration system is redundant and complex, making it impossible to maintain the liquid pressure in real time; the accumulator diaphragm cannot be replenished with cryogenic liquid nitrogen in a timely and accurate manner during low-temperature vibration; the low-temperature vibration signal of the accumulator diaphragm cannot be transmitted; and the accumulator diaphragm cannot be adjusted in a timely manner under different operating conditions during low-temperature vibration. Summary of the Invention

[0006] The purpose of this application is to provide a vibration fixture for an accumulator diaphragm and its control method. The fixture has a simple structure, can achieve precise pressure window control, and has the function of continuous fluid replenishment during low-temperature vibration. By optimizing the force transmission path and reducing the dead weight of the system, the fixture can achieve large-scale vibration loading on a small-tonnage vibration table, thereby improving the controllability and efficiency of the test.

[0007] To achieve the above objectives, as a first aspect of this application, this application provides a vibration fixture for an accumulator diaphragm box. The fixture includes: a fixture upper cover, a fixture lower base, a heat insulation plate, and a transition plate; the transition plate is fixed to the vibration table surface; the fixture lower base, the heat insulation plate, and the transition plate are fixedly connected; the accumulator diaphragm box is placed inside the fixture lower base; the fixture upper cover is fixedly connected to the top of the fixture lower base, and an independent cavity is formed between the inner wall of the fixture upper cover and the accumulator diaphragm box to provide a low-temperature vibration environment; the fixture upper cover has a liquid nitrogen inlet, a liquid nitrogen outlet, and a nitrogen outlet; the liquid nitrogen inlet, the liquid nitrogen outlet, and the nitrogen outlet are respectively connected to a liquid nitrogen inlet pipe, a liquid nitrogen return pipe, and a nitrogen discharge pipe.

[0008] The accumulator diaphragm vibration fixture described above further includes a temperature sensor, multiple pressure sensors, a control system, and multiple solenoid valves.

[0009] The temperature sensor, the pressure sensor, and the control system are communicatively connected;

[0010] The temperature sensor is used to detect the ambient temperature of the accumulator diaphragm box, obtain a temperature signal, and transmit the temperature signal back to the control system.

[0011] Multiple pressure sensors are respectively arranged on the liquid nitrogen inlet pipeline, the liquid nitrogen return pipeline and the nitrogen discharge pipeline, for transmitting pressure signals back to the control system;

[0012] Multiple solenoid valves are respectively arranged on the liquid nitrogen inlet pipeline, the liquid nitrogen return pipeline and the nitrogen discharge pipeline to control the opening and closing of each pipeline;

[0013] The control system sends open or close signals to the solenoid valve based on temperature and pressure signals, thereby controlling the replenishment of liquid nitrogen or the discharge of nitrogen gas.

[0014] The accumulator diaphragm vibration fixture described above further includes a vibration sensor and a vibration sensor adapter.

[0015] The vibration sensor adapter is provided with sensor mounting positions in three directions: X, Y, and Z.

[0016] The vibration sensor is installed at the sensor mounting position;

[0017] The tooling cover is provided with a sinking groove sensor fixing position;

[0018] The lower base of the tooling is provided with a lower fixing position;

[0019] The sensor adapter is installed at the sensor fixing position or the lower fixing position of the sensor in the sinkhole.

[0020] The accumulator diaphragm vibration fixture described above has a diaphragm inflation outlet on its lower base for inflating the accumulator diaphragm.

[0021] The accumulator diaphragm vibration fixture described above, wherein the temperature sensor includes a first temperature sensor and a second temperature sensor;

[0022] The first temperature sensor is located at the bottom of the accumulator diaphragm box;

[0023] The second temperature sensor is located on the top of the tooling cover.

[0024] The accumulator diaphragm vibration fixture described above, wherein the solenoid valve includes: a first solenoid valve, a second solenoid valve, a third solenoid valve, and a fourth solenoid valve;

[0025] The liquid nitrogen replenishment tank is installed at the liquid nitrogen outlet via pipeline and the first solenoid valve;

[0026] The nitrogen outlet is connected to the first pressure gauge and the second solenoid valve via a pipeline;

[0027] The ground-based liquid nitrogen tank is installed at the liquid nitrogen inlet via pipelines and the third solenoid valve.

[0028] The air source is connected to the fourth solenoid valve, the second pressure gauge and the adapter pipe through the air inlet pipe. The adapter pipe is connected to the diaphragm inlet of the accumulator diaphragm.

[0029] The accumulator diaphragm box vibration fixture described above, wherein the lower base of the fixture has a lower base fixing hole;

[0030] The insulation board has insulation board fixing holes;

[0031] The adapter plate has tooling base fixing holes;

[0032] The tooling base fasteners pass through the lower base fixing holes, the insulation plate fixing holes, and the tooling base fixing holes, respectively.

[0033] The accumulator diaphragm vibration fixture described above is provided with a sealing ring at the connection between the fixture's upper cover and the accumulator diaphragm.

[0034] As a second aspect of this application, this application provides a method for controlling the vibration fixture of an accumulator diaphragm, applied to the aforementioned vibration fixture of the accumulator diaphragm, the method comprising:

[0035] Gas replacement: The second and fourth solenoid valves are opened and closed alternately by the control system. First, helium is used to pressurize and depressurize the inner cavity of the accumulator diaphragm at least 4 times. Then, the above pressurization and depressurization cycle is repeated in the cavity between the accumulator diaphragm and the tool cover.

[0036] Leakage check: Use a helium detector to check the airtightness between the accumulator diaphragm and the tooling cover, as well as the leakage rate at each pipeline connection.

[0037] Inflation of diaphragm and cavity: The control system opens the second or fourth solenoid valve through electrical signal transmission to inflate the accumulator diaphragm cavity or the cavity formed by the accumulator diaphragm and the tooling cover.

[0038] Liquid nitrogen filling: The control system opens the third and second solenoid valves via electrical signal transmission. Liquid nitrogen is then added from the ground liquid nitrogen tank into the tooling through the process pipe until liquid nitrogen is discharged from the outlet of the second solenoid valve.

[0039] The control method for the accumulator diaphragm vibration fixture described above also includes accumulator vibration testing: applying random / sinusoidal excitation in the axial, radial, and tangential directions in the order of transportation vibration, low-frequency vibration, high-frequency vibration, and fixed-frequency vibration; performing a frequency sweep before each operating condition and performing another frequency sweep after all operating conditions are completed.

[0040] The beneficial effects achieved by this application are as follows:

[0041] (1) This application extracts the accumulator diaphragm box for low-temperature vibration and vibration test, without the need for large or extra-large vibration table for vibration test, which simplifies the system complexity and the feasibility of operation, and solves the problem of redundant and complicated construction of accumulator vibration system.

[0042] (2) The vibration sensor of this application is installed on the cantilever of the sensor adapter, so that the vibration sensor does not directly contact the tooling, thus extending the stability of the vibration sensor under low temperature vibration and the accuracy of the transmitted signal.

[0043] (3) This application integrates vibration sensor, pressure sensor, temperature sensor and solenoid valve into the same control system, pre-designs pressure band and temperature range, automatically replenishes liquid nitrogen and discharges nitrogen during vibration, maintains pressure within the preset pressure range, prevents overpressure, and improves vibration efficiency.

[0044] (4) In the low-temperature vibration of the accumulator diaphragm in this application, it is divided into four stages: transportation vibration, low-frequency vibration, high-frequency vibration, and constant-frequency vibration. Liquid nitrogen is used to fill different pressure values ​​in different stages to cover all test and flight phases, thus solving the problem of the inability to address the low-temperature vibration of the accumulator diaphragm under different operating conditions.

[0045] The issue of time regulation. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0047] Figure 1 This is an exploded view of a vibration fixture for an accumulator diaphragm box according to an embodiment of this application.

[0048] Figure 2 This is a cross-sectional view of a vibration fixture for an accumulator diaphragm according to an embodiment of this application.

[0049] Figure 3 This is a schematic diagram of low-temperature vibration control of the accumulator diaphragm box vibration fixture according to an embodiment of this application.

[0050] Reference numerals: 1- Fixture top cover; 2- Accumulator diaphragm box; 3- Fixture lower base; 4- Insulation plate; 6- Adapter pipe; 7- Adapter plate; 8- Sealing ring; 9- Vibration table surface; 111- Liquid nitrogen inlet; 112- Liquid nitrogen outlet; 113- Nitrogen outlet; 114- Fixture top cover fixing hole; 115- Settling tank sensor fixing position; 211- Diaphragm box fastener; 212- Fixture base fastener; 213- Adapter plate fastener; 214- Diaphragm box inflation nozzle; 215- Diaphragm box outer shell; 216- Diaphragm box diaphragm; 2 17-First temperature sensor; 218-Second temperature sensor; 219-Control system; 311-Membrane box inflation outlet; 312-Lower base fixing hole; 313-Sensor lower fixing position; 314-Reinforcing rib; 315-Membrane box fixing hole; 411-Insulation plate fixing hole; 412-Insulation plate air pipe outlet; 511-Vibration sensor adapter; 512-Vibration control table sensor mounting hole; 513-Sensor adapter fixing bolt; 711-Tooling base fixing hole; 712-Vibration table surface fixing hole. Detailed Implementation

[0051] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0052] like Figure 1-3As shown, this application provides a vibration fixture for an accumulator diaphragm box. The fixture includes: a fixture upper cover 1, a fixture lower base 3, a heat insulation plate 4, and an adapter plate 7; the vibration table 9 is horizontally arranged, and the adapter plate 7 is fixed to the vibration table 9 by adapter plate fasteners 213. The adapter plate 7 is a flat plate, and the adapter plate 7 has vibration table fixing holes 712. The adapter plate fasteners 213 pass through the vibration table fixing holes 712 and are fixedly connected to the mounting holes on the vibration table 9; the fixture lower base 3, the heat insulation plate 4, and the adapter plate 7 are fixed. Connection; the accumulator diaphragm box 2 is placed inside the lower base 3 of the fixture; the upper cover 1 of the fixture is fixedly connected to the top of the lower base 3 of the fixture, and the upper cover 1 of the fixture has a raised center in the shape of a flange cap. An independent cavity is formed between the inner wall of the upper cover 1 of the fixture and the accumulator diaphragm box 2 to provide a low temperature vibration environment; the upper cover 1 of the fixture has a liquid nitrogen inlet 111, a liquid nitrogen outlet 112 and a nitrogen outlet 113; the liquid nitrogen inlet 111, the liquid nitrogen outlet 112 and the nitrogen outlet 113 are respectively connected to a liquid nitrogen inlet pipeline, a liquid nitrogen return pipeline and a nitrogen discharge pipeline.

[0053] This application discloses a vibration fixture for an accumulator diaphragm to achieve individual vibration. Accumulator diaphragm box 2 Low-temperature vibration tests were conducted to address the redundancy and complexity in the construction of the accumulator vibration system.

[0054] As a specific embodiment of the present invention, the tooling has an overall cylindrical shape, which reduces the height of the center of gravity and increases the stability of structural vibration.

[0055] like Figure 1 As shown, the lower base 3 of the fixture has a lower base fixing hole 312; the insulation plate 4 has an insulation plate fixing hole 411; the adapter plate 7 has a fixture base fixing hole 711; the fixture base fastener 212 passes through the lower base fixing hole 312, the insulation plate fixing hole 411, and the fixture base fixing hole 711 respectively. The fixture base fastener 212 passes through all three holes, connecting the lower base 3, the insulation plate 4, and the adapter plate 7 together.

[0056] like Figure 1 As shown, the lower base 3 of the fixture is a hollow cylinder, and the top of the lower base 3 of the fixture has a diaphragm box fixing hole 315. The accumulator diaphragm box 2 has bolt fastening holes on its flange, and the edge of the upper cover 1 of the fixture has a fixture cover fixing hole 114. The diaphragm box fastener 211 passes through the fixture cover fixing hole 114 of the upper cover 1 of the fixture, the bolt fastening hole of the accumulator diaphragm box 2, and the diaphragm box fixing hole 315 of the lower base 3 of the fixture, thereby realizing the fixed connection of the upper cover 1 of the fixture, the accumulator diaphragm box 2, and the lower base 3 of the fixture.

[0057] As a specific embodiment of the present invention, the accumulator diaphragm vibration fixture further includes a temperature sensor, multiple pressure sensors, a control system 219, and multiple solenoid valves; the temperature sensor, pressure sensors, and control system 219 are communicatively connected; the temperature sensor is used to detect the vibration environment temperature of the accumulator diaphragm 2, obtain a temperature signal, and transmit the temperature signal back to the control system 219; multiple pressure sensors are respectively arranged on the liquid nitrogen inlet pipeline, liquid nitrogen return pipeline, and nitrogen discharge pipeline, and are used to transmit pressure signals back to the control system 219; multiple solenoid valves are respectively arranged on the liquid nitrogen inlet pipeline, liquid nitrogen return pipeline, and nitrogen discharge pipeline, and are used to control the opening and closing of each pipeline; the control system 219 sends open or close signals to the solenoid valves according to the temperature signal and pressure signal, controlling the replenishment of liquid nitrogen or the discharge of nitrogen.

[0058] Understandably, this application incorporates temperature control regulation. A first temperature sensor 217 and a second temperature sensor 218 are respectively installed on the upper and lower parts of the fixture, along with pressure sensors (P1 / P2 / P3 / P4) distributed on the liquid nitrogen inlet pipeline, liquid nitrogen return pipeline, and nitrogen discharge pipeline. These sensors transmit signals back to the control system 219, thereby issuing open / close signals to the solenoid valves (Z1 / Z2 / Z3 / Z4) at the control ends of each pipeline to regulate the entire system. A liquid nitrogen inlet 111, a liquid nitrogen outlet 112, and a nitrogen outlet 113 are designed on the fixture's upper cover 1 to enable timely replenishment of liquid nitrogen and discharge of nitrogen gas, preventing overpressure. This solves the problem of the accumulator diaphragm 2 being unable to replenish cryogenic liquid nitrogen in a timely and accurate manner during low-temperature vibration.

[0059] like Figure 1 As shown, the accumulator diaphragm box vibration fixture also includes a vibration sensor and a vibration sensor adapter 511; the vibration sensor adapter 511 is provided with sensor mounting positions in three directions: X, Y, and Z; the vibration sensor is installed at the sensor mounting position; the fixture upper cover 1 is provided with a sinker sensor fixing position 115, which is located at the fixing hole of the fixture upper cover 1, and the sinker sensor fixing position 115 facilitates the installation of the vibration sensor adapter 511; the fixture lower base 3 is provided with a sensor lower fixing position 313; the sensor adapter is installed at the sinker sensor fixing position 115 or the sensor lower fixing position 313.

[0060] Understandably, the vibration sensor adapter 511 is equipped with a vibration control panel sensor mounting hole 512 and a sensor adapter fixing bolt 513; the sensor adapter fixing bolt 513 is matched and connected to the sensor fixing position 115 or the lower fixing position 313 of the tooling. The vibration sensor is mounted on the cantilever of the sensor adapter, which is a cantilever design, so that the vibration sensor does not directly contact the tooling, thus extending the stability of the vibration sensor under low-temperature vibration and improving the accuracy of the transmitted signal. This solves the problem of the accumulator diaphragm 2 being unable to transmit low-temperature vibration signals.

[0061] Preferably, the sensor adapter is made of the same fiberglass material as the lower base 3 of the fixture. Without changing the vibration transmission level, it isolates the influence of the low temperature of the fixture on the sensor and improves the success rate of the vibration test.

[0062] like Figure 1 As shown, the lower base 3 of the tooling is provided with a diaphragm box inflation outlet 311, and the diaphragm box inflation nozzle 214 is connected to the diaphragm box inflation outlet 311. The insulation plate 4 has an insulation plate air pipe outlet 412, and the diaphragm box inflation nozzle 214 extends into the insulation plate air pipe outlet 412. The diaphragm box inflation nozzle 214 is connected to the diaphragm box inflation outlet 311 for use in inflating the accumulator diaphragm box 2.

[0063] like Figure 1 As shown, the lower base 3 of the fixture is provided with reinforcing ribs 314 on its outer circumference. The reinforcing ribs 314 increase the stability of the structure under low-temperature vibration environment. Preferably, there are 6 reinforcing ribs 314, but the number of reinforcing ribs 314 is not limited here. The lower base 3 of the fixture is provided with lower base fixing holes 312 at the positions where the reinforcing ribs 314 are not provided, and the bottom is provided with a lower base opening or a sensor lower fixing position 313.

[0064] like Figure 2 and 3 As shown, the temperature sensor includes a first temperature sensor 217 and a second temperature sensor 218; the first temperature sensor 217 is disposed at the bottom of the accumulator diaphragm box 2; and the second temperature sensor 218 is disposed at the top of the tooling cover 1.

[0065] like Figure 3 As shown, the solenoid valves include: a first solenoid valve (Z1), a second solenoid valve (Z2), a third solenoid valve (Z3), and a fourth solenoid valve (Z4); the liquid nitrogen replenishment tank is installed at the liquid nitrogen outlet 112 via a pipeline and the first solenoid valve; the nitrogen outlet 113 is connected to the first pressure gauge and the second solenoid valve via a pipeline; the ground liquid nitrogen tank is installed at the liquid nitrogen inlet via a pipeline and the third solenoid valve; the gas source is connected to the adapter pipe 6 via the fourth solenoid valve, the second pressure gauge, and the adapter pipe 6 is connected to the diaphragm filling nozzle 214 of the accumulator diaphragm 2.

[0066] As a specific embodiment of the present invention, the cryogenic vibration test of the accumulator diaphragm 2 is divided into four stages: transportation vibration, low-frequency vibration, high-frequency vibration, and constant-frequency vibration. Liquid nitrogen is charged at different pressure values ​​in different stages to cover all test and flight phases, including the initial liquid inlet of the diaphragm 2 into the rocket delivery pipeline inside the accumulator, the water hammer effect during engine start-up and shutdown, and the actual pressure changes in the pipeline during flight. This solves the problem of the inability to timely adjust the accumulator diaphragm 2 under different operating conditions during cryogenic vibration.

[0067] like Figure 2As shown, a sealing ring 8 is provided at the connection between the tooling cover 1 and the accumulator diaphragm box 2. The sealing ring 8 is used to seal the connection between the tooling cover 1 and the accumulator diaphragm box 2, so that the gas filled into the cavity between the tooling cover 1 and the accumulator diaphragm box 2 will not leak.

[0068] like Figure 2 As shown, the accumulator diaphragm box 2 includes a diaphragm box housing 215 and a diaphragm box sheet 216, with the diaphragm box sheet 216 disposed inside the diaphragm box housing 215.

[0069] The installation method of the accumulator diaphragm vibration fixture of the present invention is as follows:

[0070] The adapter plate 7 is fixed to the vibration table surface 9 using eight hexagonal adapter plate fasteners 213. Eight fixture base fasteners 212 are passed through the lower base fixing holes 312, the insulation plate fixing holes 411, and the fixture base fixing holes 711 of the adapter plate 7, respectively, to achieve a fixed connection. The accumulator diaphragm box 2 is placed inside the lower fixture base 3. The accumulator diaphragm box 2 has bolt fastening holes on its flange. The diaphragm box fasteners 211 are fixed to the diaphragm box fixing holes 315 on the upper part of the lower fixture base 3 via the fixture upper cover 1 and the accumulator diaphragm box 2. A sealing ring 8 is installed between the fixture upper cover 1 and the diaphragm box outer shell 215 of the accumulator diaphragm box 2. The second temperature sensor 218 is attached to the upper part of the fixture upper cover 1, and the first temperature sensor 217 is attached to the bottom of the accumulator diaphragm box 2.

[0071] The connection method of the accumulator diaphragm vibration fixture of the present invention is as follows:

[0072] The ground-based liquid nitrogen tank is installed at the liquid nitrogen inlet via a pipeline and a third solenoid valve (Z3). The liquid nitrogen replenishment pipe is installed at the liquid nitrogen outlet 112 via a pipeline and a first solenoid valve (Z1). The nitrogen outlet 113 is connected via a pipeline, a first pressure gauge (P1), and a second solenoid valve (Z2). The adapter pipe 6 is connected to the diaphragm filling nozzle 214 of the accumulator diaphragm box 2. The gas source (helium) is connected to the adapter pipe 6 via the filling pipe, a fourth solenoid valve (Z4), a second pressure gauge (P2), and the accumulator diaphragm box 2.

[0073] The first solenoid valve (Z1), the second solenoid valve (Z2), the third solenoid valve (Z3), the fourth solenoid valve (Z4), the first pressure gauge (P1), the second pressure gauge (P2), the first temperature sensor 217, and the second temperature sensor 218 are connected to the control system 219 via an electrical signal transmission line, and the system status is adjusted in real time according to the temperature and pressure data.

[0074] Example 2

[0075] This application provides a method for controlling the vibration of an accumulator diaphragm, applicable to the accumulator diaphragm vibration fixture, the method comprising:

[0076] First, install the fixture: fix the adapter plate 7 on the vibration table 9; fix the insulation plate 4 and the lower base 3 of the fixture coaxially to the adapter plate 7 with fasteners; place the accumulator diaphragm box 2 inside the lower base 3 of the fixture and press it with the upper cover 1 of the fixture to form a sealed low temperature cavity.

[0077] Gas replacement: The second and fourth solenoid valves are opened and closed alternately by the control system 219. First, the inner cavity of the accumulator diaphragm 2 is pressurized and depressurized at least 4 times with 0.8MPa helium gas. Then, the above pressurization and depressurization cycle is repeated in the cavity between the accumulator diaphragm 2 and the tooling cover 1.

[0078] Understandably, by controlling the solenoid valves Z2 and Z4 alternately opening and closing through the control system 219, the inner cavity of the accumulator diaphragm 2 is first subjected to at least 4 "pressurization-depressurization" cycles using 0.8MPa helium gas, and then the above cycle is repeated for the cavity between the accumulator diaphragm 2 and the tooling cover 1, so that the pressure in both the inner cavity of the diaphragm and the cavity is 0.8MPa.

[0079] Specifically, the control system 219 opens solenoid valve Z2 via an electrical signal, connecting the gas source (helium) to solenoid valve Z4. Then, the control system 219 opens solenoid valve Z4 again via an electrical signal, allowing the gas source (helium) to replace the gas in the accumulator diaphragm 2. The pressure is increased to 0.8 MPa. Then, solenoid valve Z4 is closed, disconnecting it from the gas source (helium). Solenoid valve Z4 is then opened again until the pressure inside the chamber reaches 0.1 MPa. This process is repeated four times. Then, 0.8 MPa of helium is added to the accumulator diaphragm 2. After charging is complete, solenoid valves Z4 and Z2 are closed, and the gas source (helium) is disconnected.

[0080] Connect the helium gas source to solenoid valve Z2. Then, control system 219 opens solenoid valve Z2 via an electrical signal, allowing the helium gas source to replace the gas in the cavity formed by accumulator diaphragm 2 and tooling cover 1. Fill the cavity to 0.8 MPa with helium, then close solenoid valve Z2, disconnect the connection between solenoid valve Z2 and the helium gas source, and reopen solenoid valve Z2 until the pressure inside the chamber reaches 0.1 MPa. Repeat this process four times. After completion, close solenoid valve Z4 and disconnect the helium gas source.

[0081] Leakage check: Use a helium detector to check the airtightness between the accumulator diaphragm 2 and the tooling cover 1, as well as the leakage rate at each pipeline connection.

[0082] Specifically, use a helium detector to check the airtightness between the accumulator diaphragm box 2 and the tooling cover 1, as well as the leakage rate at each pipeline connection. The leakage rate at each pipeline connection should be ≤1×10⁻⁶. -5 Pa·m 3 / s, membrane leakage rate should be ≤1×10 -8 Pa·m 3 / s. Note: Monitor the pressure change of accumulator diaphragm 2 in real time. If the pressure is 0MPa, the diaphragm or pipeline will rupture.

[0083] Preferably, the leak rate is checked using a helium mass spectrometer, requiring a membrane leak rate ≤1×10⁻⁶. -8 Pa·m3 / s, leakage rate at pipe connection ≤1×10 -5 Pa·m 3 / s.

[0084] Inflation of diaphragm and cavity: The control system 219 opens the second or fourth solenoid valve through electrical signal transmission to inflate the inner cavity of the accumulator diaphragm 2 or the cavity formed by the accumulator diaphragm 2 and the tooling cover 1.

[0085] Specifically, according to the test condition table, the inner cavity of the membrane capsule is filled to the target pressure in the range of 0.15 to 1 MPa through solenoid valves Z2 and Z4, while the cavity pressure is simultaneously adjusted to the corresponding target pressure in the range of 0.1 to 0.7 MPa.

[0086] The test conditions are as follows:

[0087]

[0088] Liquid nitrogen filling: Control system 219 opens the third solenoid valve and the second solenoid valve through electrical signal transmission. The ground liquid nitrogen tank fills the tooling with liquid nitrogen through the process pipe until liquid nitrogen is discharged from the outlet of the second solenoid valve.

[0089] During liquid nitrogen filling, the control system 219 opens solenoid valves Z3 and Z2 to inject liquid nitrogen into the cavity until liquid is seen at the outlet. Then, it closes solenoid valve Z2 and opens solenoid valve Z1 to establish self-circulation. When the liquid level in the replenishment tank reaches 200L and the readings of the first temperature sensor 217 and the second temperature sensor 218 are stable between -196℃ and -180℃, and the fluctuations of the first pressure sensor (P1) and the second pressure sensor (P2) are ≤0.05MPa, the system enters the vibration preparation state.

[0090] As a specific embodiment of the present invention, after the normal temperature vibration environment test in highway transportation is completed, low temperature vibration in the low temperature liquid nitrogen zone is conducted. First, liquid nitrogen is added. The control system 219 opens solenoid valves Z3 and Z2 via electrical signal transmission. Liquid nitrogen is added to the fixture from the ground liquid nitrogen tank through the process pipe. Once liquid nitrogen is discharged from the outlet of solenoid valve Z2, solenoid valve Z2 is closed and solenoid valve Z1 is opened. After the fixture is filled with liquid nitrogen, liquid nitrogen flows back into the liquid nitrogen replenishment tank. Liquid nitrogen is added to the ground until the liquid nitrogen replenishment tank reaches 200L, at which point replenishment stops. During the vibration test, closing solenoid valve Z3 disconnects the ground liquid nitrogen tank, and liquid nitrogen is replenished into the fixture through the liquid nitrogen replenishment tank. After the liquid nitrogen is filled, the liquid nitrogen in the tooling is left to stand for 30 minutes until the liquid nitrogen no longer vaporizes and boils violently. The temperature of the first temperature sensor 217 and the second temperature sensor 218 stabilizes within a certain range (-180℃ to -196℃), and the pressure fluctuation range of the first pressure sensor P1 and the second pressure sensor P2 stabilizes within 0.05MPa. During this period, the sensor pressure and the temperature at the measuring point are monitored.

[0091] Accumulator vibration test: Random / sinusoidal excitation is applied sequentially in the axial, radial and tangential directions in the order of transportation vibration, low frequency vibration, high frequency vibration and fixed frequency vibration; a frequency sweep is performed before each working condition and a frequency sweep is performed after all working conditions are completed.

[0092] This application transforms the pressure state of the accumulator diaphragm 2 under low temperature conditions into a lower limit pressure, a working pressure, and an upper limit pressure. These three pressure bands are maintained and protected respectively, and the core vibration frequency is subjected to fixed-frequency vibration. This improves the accuracy of the vibration data of the accumulator diaphragm 2 in covering the actual flight operating range and enhances the stability of the accumulator under low temperature conditions.

[0093] Specifically, vibration tests are conducted in three directions: shaft, radial, and tangential. During each direction, transportation vibration, low-frequency vibration, and high-frequency vibration are performed sequentially. After completing the first three conditions in each direction, fixed-frequency vibration is then performed in all three directions. After each test condition loading is completed, the test data and product condition are checked. Only if no abnormalities are found can the test condition be switched or the test ended. A frequency sweep is performed before each random vibration, and another frequency sweep is performed after all vibration conditions in each direction are completed.

[0094] During the test, the pressure sensor signal is monitored, and the test is stopped if any abnormality is detected.

[0095] Real-time control: During the vibration process, the control system 219 automatically opens and closes solenoid valves Z1 to Z4 based on the feedback signals from the first temperature sensor 217, the second temperature sensor 218 and the pressure sensor to replenish liquid nitrogen or discharge nitrogen gas, so that the pressure inside the diaphragm box and the cavity is always kept within the set target pressure range.

[0096] Data interpretation: Real-time acquisition of X / Y / Z vibration signals installed on the vibration sensor adapter 511. If abnormal amplitude or sudden pressure occurs, the machine is immediately stopped and the test is marked as invalid.

[0097] The beneficial effects achieved by this application are as follows:

[0098] (1) This application extracts the accumulator diaphragm box for low-temperature vibration and vibration test, without the need for large or extra-large vibration table for vibration test, which simplifies the system complexity and the feasibility of operation, and solves the problem of redundant and complicated construction of accumulator vibration system.

[0099] (2) The vibration sensor of this application is installed on the cantilever of the sensor adapter, so that the vibration sensor does not directly contact the tooling, thus extending the stability of the vibration sensor under low temperature vibration and the accuracy of the transmitted signal.

[0100] (3) This application integrates vibration sensor, pressure sensor, temperature sensor and solenoid valve into the same control system, pre-designs pressure band and temperature range, automatically replenishes liquid nitrogen and discharges nitrogen during vibration, maintains pressure within the preset pressure range, prevents overpressure, and improves vibration efficiency.

[0101] (4) In the low-temperature vibration of the accumulator diaphragm in this application, it is divided into four stages: transportation vibration, low-frequency vibration, high-frequency vibration and fixed-frequency vibration. Liquid nitrogen is filled with different pressure values ​​in different stages to cover all test and flight stages, thus solving the problem that the accumulator diaphragm cannot be timely adjusted under different operating conditions in the low-temperature vibration.

[0102] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0103] In the description of this application, the word "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0104] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A vibration fixture for an accumulator diaphragm, characterized in that, The fixture includes: a top cover, a bottom base, an insulation plate, and an adapter plate; The adapter plate is fixed to the vibration table surface; The tooling base, the insulation plate, and the adapter plate are fixedly connected; The accumulator diaphragm box is placed inside the lower base of the tooling. The tooling cover is fixedly connected to the top of the tooling base, and an independent cavity is formed between the inner wall of the tooling cover and the accumulator diaphragm box to provide a low-temperature vibration environment; The tooling cover is provided with a liquid nitrogen inlet, a liquid nitrogen outlet, and a nitrogen outlet; The liquid nitrogen inlet, the liquid nitrogen outlet, and the nitrogen outlet are respectively connected to a liquid nitrogen inlet pipeline, a liquid nitrogen return pipeline, and a nitrogen discharge pipeline.

2. The accumulator diaphragm vibration fixture according to claim 1, characterized in that, The fixture also includes a temperature sensor, multiple pressure sensors, a control system, and multiple solenoid valves; The temperature sensor, the pressure sensor, and the control system are communicatively connected; The temperature sensor is used to detect the ambient temperature of the accumulator diaphragm box, obtain a temperature signal, and transmit the temperature signal back to the control system. Multiple pressure sensors are respectively arranged on the liquid nitrogen inlet pipeline, the liquid nitrogen return pipeline and the nitrogen discharge pipeline, for transmitting pressure signals back to the control system; Multiple solenoid valves are respectively arranged on the liquid nitrogen inlet pipeline, the liquid nitrogen return pipeline and the nitrogen discharge pipeline to control the opening and closing of each pipeline; The control system sends open or close signals to the solenoid valve based on temperature and pressure signals, thereby controlling the replenishment of liquid nitrogen or the discharge of nitrogen gas.

3. The accumulator diaphragm vibration fixture according to claim 1, characterized in that, The fixture also includes a vibration sensor and a vibration sensor adapter; The vibration sensor adapter is provided with sensor mounting positions in three directions: X, Y, and Z. The vibration sensor is installed at the sensor mounting position; The tooling cover is provided with a sinking groove sensor fixing position; The lower base of the tooling is provided with a lower fixing position; The sensor adapter is installed at the sensor fixing position or the lower fixing position of the sensor in the sinkhole.

4. The accumulator diaphragm vibration fixture according to claim 1, characterized in that, The lower base of the fixture is provided with a diaphragm inflation outlet for inflating the accumulator diaphragm.

5. The accumulator diaphragm vibration fixture according to claim 2, characterized in that, The temperature sensor includes a first temperature sensor and a second temperature sensor; The first temperature sensor is located at the bottom of the accumulator diaphragm box; The second temperature sensor is located on the top of the tooling cover.

6. The accumulator diaphragm vibration fixture according to claim 2, characterized in that, The solenoid valve includes: a first solenoid valve, a second solenoid valve, a third solenoid valve, and a fourth solenoid valve; The liquid nitrogen replenishment tank is installed at the liquid nitrogen outlet via pipeline and the first solenoid valve; The nitrogen outlet is connected to the first pressure gauge and the second solenoid valve via a pipeline; The ground-based liquid nitrogen tank is installed at the liquid nitrogen inlet via pipelines and the third solenoid valve. The air source is connected to the fourth solenoid valve, the second pressure gauge and the adapter pipe through the air inlet pipe. The adapter pipe is connected to the diaphragm inlet of the accumulator diaphragm.

7. The accumulator diaphragm vibration fixture according to claim 1, characterized in that, The tooling base has a lower base fixing hole; The insulation board has insulation board fixing holes; The adapter plate has tooling base fixing holes; The tooling base fasteners pass through the lower base fixing holes, the insulation plate fixing holes, and the tooling base fixing holes, respectively.

8. The accumulator diaphragm vibration fixture according to claim 1, characterized in that, A sealing ring is provided at the connection between the tooling cover and the accumulator diaphragm box.

9. A method for controlling the vibration fixture of an accumulator diaphragm, characterized in that, The method, applied to the accumulator diaphragm vibration fixture according to any one of claims 1-8, comprises: Gas replacement: The second and fourth solenoid valves are opened and closed alternately by the control system. First, helium is used to pressurize and depressurize the inner cavity of the accumulator diaphragm at least 4 times. Then, the above pressurization and depressurization cycle is repeated in the cavity between the accumulator diaphragm and the tool cover. Leakage check: Use a helium detector to check the airtightness between the accumulator diaphragm and the tooling cover, as well as the leakage rate at each pipeline connection. Inflation of diaphragm and cavity: The control system opens the second or fourth solenoid valve through electrical signal transmission to inflate the accumulator diaphragm cavity or the cavity formed by the accumulator diaphragm and the tooling cover. Liquid nitrogen filling: The control system opens the third and second solenoid valves via electrical signal transmission. Liquid nitrogen is then added from the ground liquid nitrogen tank into the tooling through the process pipe until liquid nitrogen is discharged from the outlet of the second solenoid valve.

10. The method for controlling the vibration fixture of the accumulator diaphragm according to claim 9, characterized in that, It also includes accumulator vibration testing: random / sinusoidal excitation is applied sequentially in the axial, radial, and tangential directions in the order of transportation vibration, low-frequency vibration, high-frequency vibration, and fixed-frequency vibration; a frequency sweep is performed before each working condition and another frequency sweep is performed after all working conditions are completed.

Images