Assembly and testing method of special control valve for aerospace

Abstract

The invention provides an assembly test method for a special aerospace control valve, which tests whether the opening and closing pressure of the control valve is successful, specifically: using a micrometer to measure the matching position of the shaft hole of the pull rod and the lower shell body, and matching them to meet the coaxiality requirement of the up and down displacement of the components in the valve; by calculating the S1 stroke and the torque value of each connection, the assembly process of the special aerospace control valve is solidified, and the resonance and leakage problems of the control valve are avoided; during the debugging process, the position of the adjusting screw is adjusted to control the opening pressure of the control valve, and the air tightness inspection is performed on each threaded connection, outlet, adjusting screw and exhaust hole, and the leakage rate of the valve seat in the medium after the control valve reaches the predetermined pressure reaches 3 to 5 bubbles / second as the basis for successful opening, and the leakage rate of the valve seat in the medium is 0 bubbles / minute when the control valve reaches the lower limit of the required pressure value as the basis for successful closing, thereby solidifying the opening and closing indicators of the control valve.

Description

Technical Field

[0001] The invention relates to the technical field of measurement and assembly test of a special aerospace control valve, and in particular to an assembly test method of a special aerospace control valve. Background Art

[0002] The safety valve is one of the important units in the booster delivery system of the launch vehicle to control and maintain the stability of the tank pressure. The command valve can accurately control the opening and closing of the safety valve. During the booster process of the rocket tank, when the tank pressure exceeds the set value, the command valve controls the safety valve to open. After the tank pressure is relieved to the set pressure value, the command valve controls the safety valve to close.

[0003] During the traditional assembly and testing process of the command valve, resonance, leakage, and closing pressure exceeding the lower limit are prone to occur. During this period, non-metallic seals and gaskets need to be replaced continuously to solve the above problems. The traditional command valve assembly and testing method can no longer meet the growing needs of high-density launch missions.

[0004] And with the continuous development of a new generation of high-thrust launch vehicles, higher requirements are placed on the reliability of command valves, requiring more efficient and reasonable command valve assembly and testing methods. Summary of the invention

[0005] In view of the defects in the prior art, the object of the present invention is to provide an assembly and testing method for aerospace-specific control valves.

[0006] The assembly and testing method of the aerospace-specific control valve provided by the present invention comprises:

[0007] Step 1: Use a micrometer to measure the matching position of the tie rod and the shaft hole of the lower shell, and select the matching standard: the single-side clearance between the tie rod and the shaft hole of the lower shell is 0.01mm~0.02mm, then assemble the pilot valve and use the tooling to determine the torque;

[0008] Step 2: Test whether the pilot valve opens and closes the pressure successfully, specifically:

[0009] The opening pressure of the pilot valve is adjusted by adjusting the position of the adjusting screw, and the air tightness of each threaded connection, outlet, adjusting screw and exhaust hole is checked. When the pilot valve reaches the predetermined pressure and the valve seat is in the medium and meets the preset conditions, it is considered to be successfully opened. When the pilot valve is at the lower limit of the required pressure value and the valve seat is in the medium with 0 bubbles / minute, it is considered to be successfully closed.

[0010] When the closing pressure exceeds the lower limit of the required value, the rebound speed of the live valve can be accelerated by adjusting the size of the gasket or replacing the spring with a higher stiffness.

[0011] Preferably, the assembly of the command valve in step 1 comprises: using the pull sleeve as an assembly base, sequentially installing a live valve, a gasket, a small spring and a pull rod, which is recorded as component A, wherein the pull rod is threadedly connected to the pull sleeve;

[0012] Take the lower housing as the assembly base, install component A, diaphragm and spring seat in sequence, and tighten them with double nuts to assemble the lower housing assembly;

[0013] The lower housing assembly is used as the assembly base, and the pressure pad, large spring, spring plate, upper housing, adjustment screw, nut and protective cap are installed in sequence to assemble the pilot valve, wherein the upper housing is threadedly connected with the lower housing;

[0014] Record the spring force values ​​of the small spring and the large spring, and pair them up in pairs from large to small based on the two spring force values;

[0015] The corrugated protrusion of the diaphragm faces the spring seat; when the nut is installed, the flat surface faces the upper shell and the chamfered side faces outward; the chamfer of the pressure pad faces the diaphragm.

[0016] Preferably, during the assembly process, a layer of perfluoroether oil is applied to the relatively moving mating surfaces, and a layer of chemical-resistant sealing grease is applied to the two end surfaces of the small spring, the threads connecting the pull rod and the pull sleeve, the two end surfaces of the gasket, the diaphragm surface, the pressure pad surface, and the two end surfaces of the large spring.

[0017] Preferably, the use of a tool to determine the torque in step 1 includes: using a depth gauge to respectively measure the maximum value S1MAX and the minimum value S1MIN of the S1 stroke, and calculating the required gasket thickness, and the calculation formula is: X=S1MAX-S1MIN-S1+δ; wherein X is the selected thickness of the gasket; the S1 stroke is a distance between the live valve and the pull sleeve after the valve is assembled; δ is the gasket compression; S1MAX is the value measured by the measuring tool when the gasket is not installed and the valve seat is screwed to the bottom; S1MIN is the value measured by the measuring tool when the stop of the valve seat touches the live valve and does not compress the small spring;

[0018] Apply a torque of 120N·m to the upper shell and the lower shell; use the calculated gasket and valve seat to set the force of 20N·m~25N·m with the lower shell and re-measure, calculate the new S1 stroke according to the newly measured S1MAX and S1MIN, and finally meet the new S1 stroke value and record the parameters; when assembling the valve seat, select a gasket of appropriate thickness to set the new S1 stroke value to 25N·m~30N·m, and the valve seat and the lower shell are threaded;

[0019] Tighten the adjustment screw until it contacts the spring disk and stop. After the upper and lower shells have been torqued, continue to tighten the adjustment screw downward by 12 mm. Do not tighten the nut yet and torque it after debugging. When the upper and lower shells are torqued, use the hexagonal surface of the upper shell as the anti-torque clamping surface, and the torque wrench acts on the hexagonal surface of the lower shell to set the force to 120 N·m.

[0020] Preferably, when the valve seat is in the medium and leakage occurs, the valve seat is pre-pressed, and the pre-pressing depth measured by a micrometer is 0.05 mm to 0.07 mm.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides an assembly and testing method for a special aerospace control valve. Through selection, assembly, stroke measurement, debugging of opening and closing pressures, and troubleshooting measures during the debugging process, the present invention solves the problems of resonance, leakage, and closing pressure exceeding a lower limit that are prone to occur during the traditional assembly and testing of control valves, thereby improving the efficiency of the assembly and testing of control valves and the production qualification rate of control valves. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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:

[0024] Figure 1 A schematic diagram of the distribution of parts of an aerospace-specific control valve assembly A according to an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of a tooling and a force setting method of an aerospace-specific control valve assembly A according to an embodiment of the present invention;

[0026] Figure 3 A schematic diagram of the distribution of parts of a lower housing assembly of an aerospace-specific command valve according to an embodiment of the present invention;

[0027] Figure 4 A schematic diagram of the distribution of parts of a special aerospace control valve according to an embodiment of the present invention;

[0028] Figure 5 A schematic diagram of a measurement tool dedicated to aerospace according to an embodiment of the present invention;

[0029] Figure 6a To measure S1 MAX Schematic diagram of the measuring tooling when

[0030] Figure 6b To measure S1 MIN Schematic diagram of the time measurement tooling;

[0031] Figure 7A schematic diagram of a pre-pressurization method for debugging a special aerospace control valve according to an embodiment of the present invention;

[0032] Figure 8 This is a flow chart of the complete assembly test of aerospace-specific control valve according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] 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.

[0034] Example

[0035] Based on the key characteristics of the control valve, the present invention designs corresponding selection, assembly, abnormal fault handling and other methods to solve the problem of low qualified rate of the control valve. Figure 8 , the steps are as follows:

[0036] 1) Matching: 1. Use a micrometer with an accuracy of 0.001mm to measure the matching of the shaft hole of the entire batch of tie rods and the lower shell and perform matching. The single-side clearance here is required to be 0.01mm~0.02mm, so as to ensure the coaxiality requirements of the up and down displacement of component A in the valve, among which 0.01mm~0.02mm is the smallest movable clearance in the valve assembly. Here, it can be ensured that the non-metallic active valve 2 in component A falls stably into the indentation surface when rebounding. 2. Record the spring force values ​​of the small spring 4 inside component A and the large spring inside the upper shell 13, and then pair the two springs from large to small with the force value as a reference. This can prevent the resonance of the command valve.

[0037] 2) Assembly: 1. Figure 1 As shown, the pull sleeve 1 is used as the assembly base to sequentially install the live valve 2, the gasket 3, the small spring 4 and the pull rod 5; the pull rod 5 is threadedly connected to the pull sleeve 1 to form "assembly A";

[0038] Apply a layer of 7805 chemical resistant sealing grease on both ends of the small spring 4; apply a layer of 7805 chemical resistant sealing grease on the thread; apply a layer of 7805 chemical resistant sealing grease on both ends of the washer 3;

[0039] 2. If Figure 2 The tooling shown is used to torque "Component A";

[0040] Among them, the fixed torque is 5 N·m. The fixed torque here cannot be greater than 5 N·m, otherwise the pull rod will be deformed due to excessive torque; it cannot be less than 4.5 N·m, otherwise it will not pass the vibration test. The fixed torque is measured through performance test torque surveys of more than multiple product batches. The flat position of the tooling where the flat-nose pliers clamp the pull sleeve is the counter torque, and the torque wrench acts on the hexahedral clamping surface of the tooling at the pull sleeve to apply torque;

[0041] 3. If Figure 3 As shown, the lower housing 6 is used as the assembly base, and the component A, the diaphragm 10 (2 pieces) and the spring seat 7 are installed in sequence and tightened with a double nut 8 to assemble the lower housing assembly.

[0042] A layer of 7805 chemical resistant sealing grease is evenly coated on the surface of the diaphragm 10; the corrugated protrusion of the diaphragm faces the spring seat 7.

[0043] 4. The fixed torque of double nut 8 is 1.5N·m to prevent loosening.

[0044] 5. If Figure 4 As shown, the lower shell assembly is the assembly base, and the pressure pad 9, large spring 11, spring plate 12, upper shell 13, adjustment screw 14, M8 1 Hexagonal flat nut 15 (2 pieces), protective cap 16, assemble the pilot valve. The upper shell 13 is threadedly connected to the lower shell 6;

[0045] Apply 7805 chemical resistant sealing grease to both ends of the pressure pad 9 and the large spring 11; apply 7805 chemical resistant sealing grease to the threads and ball heads; M8 1 When installing, the hexagonal flat nut 15 should be installed with the flat surface facing the upper shell 13 and the chamfered side facing outward; the chamfer of the pressure pad R0.5 should face the diaphragm.

[0046] 6. Apply a layer of perfluoroether oil on the relative motion mating surfaces during assembly. Apply a layer of chemical-resistant sealing grease on the sealing parts, both ends of the spring, and the threaded mating parts.

[0047] 7. Stroke measurement: Figure 5 As shown, the stroke S1 here is the distance between the live valve 2 and the pull sleeve 1 after the valve is assembled. This stroke is a key process characteristic for controlling the pressure balance in the valve. Figure 5 As shown in the figure, place it at the valve seat 18, use a depth gauge to measure S1MAX (S1MAX is the maximum value of S1 stroke) and S1MIN (S1MIN is the minimum value of S1 stroke), and calculate the required gasket thickness. The calculation formula is:

[0048] X=S1MAX-S1MIN-S1+δ

[0049] Among them, X is the selected thickness of the gasket; Figure 6aAs shown in FIG. 1 , S1MAX is the value measured by the measuring tool when the washer is not installed and the valve seat 18 is screwed to the bottom; Figure 6b As shown, S1MIN is the value measured by the measuring tool when the stop of the valve seat hits the valve 2 and does not compress the small spring 14; δ is the compression of the gasket, which is generally between 0.1-0.2mm; after the valve seat 18 is set at the torque, the S1MAX value should be remeasured and the actual measured value of S1 should be calculated.

[0050] The upper shell 13 and the lower shell 6 apply a torque of 120N·m. The calculated gasket and valve seat 18 are selected to set the force of 20N·m~25N·m with the lower shell 6, and re-measured. The new measured S1MAX and S1MIN are calculated to get the new S1 stroke. Finally, the new S1 stroke value needs to be met and the parameters recorded; when assembling the valve seat, the new S1 value should be adjusted by selecting a gasket of appropriate thickness before tightening the fixed torque (25N·m~30N·m,). The valve seat 18 and the lower shell 6 are threaded. Because the valve needs to be tested for performance in extreme environments such as -40℃, +50℃, vibration and impact, the above torque is measured by the performance test torque of more than multiple product batches under the above extreme environments.

[0051] The adjusting screw 14 is screwed down until it contacts the spring disk 12, and then the adjusting screw 14 is screwed down 12mm after the upper shell 13 and the lower shell 6 have set the torque. The adjusting screw is screwed down 12mm to give the large spring a basic preload. Before measuring the S1 stroke, the pilot valve needs to be pre-adjusted to the working state. The subsequent debugging of the valve is also carried out within the range of 12±1mm. M8 1 Hexagonal flat nut 15 is not tightened yet, and the torque is determined after debugging. When the upper shell 13 and the lower shell 6 are torqued, the hexagonal surface of the upper shell 13 is used as the anti-torque clamping surface, and the torque wrench acts on the hexagonal surface of the lower shell 6 to set the force of 120 N·m.

[0052] 3) Debugging the opening and closing pressure values: adjust the opening pressure of the pilot valve by adjusting the position of the adjusting screw 14, and perform airtightness inspection for 1 minute at each threaded connection, outlet, and two exhaust holes at the adjusting screw 14 (check both holes at the same time). The opening pressure and closing pressure vary according to the different tank pressures of each type. When the pilot valve reaches the predetermined pressure, the valve seat is in the medium for 3 to 5 bubbles / second, which is considered to be successfully opened. When the pilot valve is at the lower limit of the required pressure value, the valve seat is in the medium for 0 bubbles / minute, which is considered to be successfully closed;

[0053] When the valve seat 18 is in the medium and leaks, the part and the valve seat 18 are pre-pressed as follows. Figure 7As shown, the pre-pressing depth measured by a micrometer is 0.05mm~0.07mm. This value is calculated through the gap deflection angle and the aspect ratio. A complete indentation can be formed when the pre-pressing depth is 0.05mm~0.07mm and observed through a 30x magnifying glass.

[0054] When the closing pressure exceeds the lower limit of the required value, adjust the Figure 1 The size of the middle washer 3 or the replacement of the small spring 4 with a larger stiffness can be increased by speeding up Figure 1 The problem can be solved by adjusting the rebound speed of the middle live valve 2.

[0055] After replacing the parts, the valve is assembled again according to the technical requirements, and the pressure sensor and pressure collector are used together with the collection frequency of 1000Hz (collecting 1000 pressure values ​​per second). The pressure value changes and the opening and closing time difference of the valve during the test are collected. Generally, the difference between the opening pressure value and the closing pressure value is ±0.015Mpa (the pressure value difference is different for different models).

[0056] By replacing Figure 1 The size of the middle gasket 3 or the replacement of the small spring 4 with a larger stiffness can solve the problem of the rebound speed of the live valve 2 during the operation of the command valve. The faster the rebound speed, the less the deflation amount, and thus the less the pressure value decreases, so that the pressure drop value is controlled within the required range; if the deflation amount is too much, the rocket will fail in the flight due to the low tank pressure, which will lead to insufficient lift and cause the launch mission to fail.

[0057] 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.

[0058] 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. An assembly and testing method for aerospace-specific control valves, characterized in that: The following steps are involved: Step 1: Use a micrometer to measure the matching position of the tie rod and the shaft hole of the lower shell, and select the matching. The matching standard is: the single-side clearance between the tie rod and the shaft hole of the lower shell is 0.01mm~0.02mm; then, assemble the pilot valve and use the tooling to determine the torque; Step 2: Test whether the pilot valve opens and closes the pressure successfully, specifically: The pilot valve opening pressure is adjusted by adjusting the position of the adjusting screw, and the air tightness of each threaded connection, outlet, adjusting screw and exhaust hole is checked; when the pilot valve reaches the predetermined pressure, the valve seat is in the medium and meets the preset conditions, it is considered to be successfully opened; when the pilot valve is at the lower limit of the required pressure value, the valve seat is in the medium with 0 bubbles / minute, it is considered to be successfully closed; When the closing pressure exceeds the lower limit of the required value, the rebound speed of the live valve can be accelerated by adjusting the size of the gasket or replacing a spring with a higher stiffness; The use of a tool to determine the torque in step 1 includes: using a depth gauge to measure the maximum value S1MAX and the minimum value S1MIN of the S1 stroke respectively, and calculating the required gasket thickness, and the calculation formula is: X=S1MAX-S1MIN-S1+δ; wherein X is the selected thickness of the gasket; the S1 stroke is a distance between the live valve and the pull sleeve after the valve is assembled; δ is the gasket compression; S1MAX is the value measured by the measuring tool when the gasket is not installed and the valve seat is screwed to the bottom; S1MIN is the value measured by the measuring tool when the stop of the valve seat touches the live valve and does not compress the small spring; Apply a torque of 120N·m to the upper shell and the lower shell; use the calculated gasket and valve seat to set the force of 20N·m~25N·m with the lower shell, and re-measure; calculate the new S1 stroke based on the newly measured S1MAX and S1MIN, and finally meet the new S1 stroke value and record the parameters; when assembling the valve seat, select a gasket of appropriate thickness to set the new S1 stroke value to 25N·m~30N·m, and the valve seat and the lower shell are threaded; Tighten the adjustment screw until it contacts the spring disk and stop. After the upper and lower shells have been torqued, continue to tighten the adjustment screw downward by 12 mm. Do not tighten the nut yet and torque it after debugging. When the upper and lower shells are torqued, use the hexagonal surface of the upper shell as the anti-torque clamping surface, and the torque wrench acts on the hexagonal surface of the lower shell to set the force to 120 N·m.

2. The assembly and testing method of aerospace-specific control valve according to claim 1 is characterized in that: The process of assembling the control valve in step 1 includes: using the pull sleeve as the assembly base, sequentially installing the live valve, the gasket, the small spring and the pull rod, which is recorded as component A, wherein the pull rod is threadedly connected to the pull sleeve; Take the lower housing as the assembly base, install component A, diaphragm and spring seat in sequence, and tighten them with double nuts to assemble the lower housing assembly; The lower housing assembly is used as the assembly base, and the pressure pad, large spring, spring plate, upper housing, adjustment screw, nut and protective cap are installed in sequence to assemble the pilot valve, wherein the upper housing is threadedly connected with the lower housing; Record the spring force values ​​of the small spring and the large spring, and pair them up in pairs from large to small based on the two spring force values; The corrugated protrusion of the diaphragm faces the spring seat; when the nut is installed, the flat surface faces the upper shell and the chamfered side faces outward; the chamfer of the pressure pad faces the diaphragm.

3. The assembly and testing method of aerospace-specific control valve according to claim 2 is characterized in that: During the assembly process, apply a layer of perfluoroether oil on the relative motion mating surfaces, and apply a layer of chemical-resistant sealing grease on both end surfaces of the small spring, the threads connecting the pull rod and the pull sleeve, both end surfaces of the gasket, the surface of the diaphragm, the surface of the pressure pad, and both end surfaces of the large spring.

4. The assembly and testing method of aerospace-specific control valve according to claim 1 is characterized in that: When the valve seat is in the medium and leakage occurs, the valve seat is pre-pressed and the pre-pressing depth is measured by a micrometer to be 0.05mm~0.07mm.

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