Method of forming a valve bellows

Abstract

This invention provides a method for forming a valve bellows diaphragm, offering a precise forming method for a 0.05mm thick valve bellows diaphragm for launch vehicles, belonging to the field of metal forming. Based on key characteristics such as the tightening torque of the valve bellows diaphragm forming tooling, the pressure during trial forming, and the pressure holding time, this invention employs a production process including raw material screening, blanking, cleaning and screening, machining, trial forming, forming, aging, and inspection, effectively improving the yield rate of bellows diaphragm production and possessing significant engineering application value.

Description

Technical Field

[0001] This invention belongs to the field of valve product manufacturing, specifically, it relates to a method for forming a corrugated diaphragm for valves. More specifically, it relates to a precision forming method for corrugated diaphragm parts used in valve products for aerospace launch vehicles. Background Technology

[0002] Diaphragm safety valves, command valves, and pressure reducing valves are high-precision valve products. The corrugated diaphragm is a pressure-sensitive element in launch vehicle valves. Its function is to sense the pressure and changes in the launch vehicle's pressurization and delivery system. Through a certain amount of deformation, it drives the valve upwards (or downwards), opening (or closing) the launch vehicle valve, thereby controlling the opening (or closing) of the launch vehicle valve to stabilize the pressure in the rocket's propellant tanks.

[0003] An existing type of valve corrugated diaphragm includes a circular planar diaphragm and annularly distributed corrugations integrally and concentrically arranged on the planar diaphragm. The diameter of the standard planar diaphragm is A, the center diameter of the standard corrugations is B, and the height of the standard corrugations is H.

[0004] Analysis of the technical specifications of corrugated diaphragms reveals that the performance of their raw materials, processing precision, and surface quality are crucial parameters that directly affect the performance of launch vehicle valves in controlling the pressure of rocket propellant tanks.

[0005] Traditional production methods for corrugated diaphragms often rely on experience and repeated trials to determine the processing sequence and parameters. This results in a long production cycle, and the production process is affected by factors such as surface scratches and foreign matter, leading to a high scrap rate. For example, it takes two months to produce a batch of corrugated diaphragms for a certain safety valve. The number of diaphragms prepared in the early stage needs to be more than five times the number of qualified diaphragms to be delivered in the end. The production qualification rate is less than 20%, and the labor cost is extremely high, which seriously restricts the overall research and development and production progress of aerospace launch vehicles.

[0006] Currently, there are more than 10 types of corrugated diaphragms in use, with an annual usage of thousands of pieces. The production task is heavy and the time is tight. Moreover, with the continuous development of the new generation of launch vehicles, higher requirements are being placed on the reliability of corrugated diaphragms. Relying on traditional production and research methods can no longer meet the mission requirements. It is urgent to design a complete and efficient corrugated diaphragm production method based on mastering the key characteristics of corrugated diaphragms in order to meet the needs of model development.

[0007] Patent document CN106363071B discloses a precision forming method for a 1mm pure aluminum launch vehicle valve rupture diaphragm. Based on the key characteristics of the diaphragm's pressure, and through the raw material selection requirements, the molding process uses a combination of laser non-destructive measurement and pressure testing to quickly and accurately determine the forming parameters. Batch production ensures the consistency of important parameters with the molding parameters, and finally, the method is verified through sampling tests.

[0008] The corrugated diaphragm involved in this invention is a metal element with a corrugated structure. It is an elastic element capable of sensing pressure changes. The material needs to be elastic and pressure-resistant rather than brittle. During valve operation, it senses pressure changes and cyclically operates. This differs from a rupture diaphragm, which is typically a thin and brittle metal sheet whose main function is to suddenly rupture under specific internal pressure or temperature conditions; it is a single-use part. Therefore, patent document CN106363071B is not applicable to the molding of corrugated diaphragms.

[0009] This invention provides a complete process and method for precision forming of valve bellows diaphragms. Addressing the essential differences between forming molds and rupture diaphragm forming molds, it employs bellows diaphragm machining tooling and aging methods, refining the precision forming method and quality assurance for bellows diaphragms. Summary of the Invention

[0010] In view of the deficiencies in the prior art, the purpose of this invention is to provide a method for forming a valve bellows diaphragm.

[0011] A method for forming a valve bellows diaphragm according to the present invention includes:

[0012] Step S1: Select raw materials based on the elongation, tensile strength, and yield strength of the steel strip material;

[0013] Step S2: According to the diaphragm size, use a diaphragm cutting tool to cut and cut the material to form a diaphragm;

[0014] Step S3: Perform the first cleaning and screening of the membrane sheets;

[0015] Step S4: Machin the diaphragm using a lathe;

[0016] Step S5: Perform a second cleaning and screening of the membrane sheet;

[0017] Step S6: Perform a test molding and record the test parameters;

[0018] Step S7: Mold the model according to the parameters recorded in the test molding record;

[0019] Step S8: Inspect the dimensions of the formed film. After inspection, package each piece individually with cotton paper, place each piece in a paper bag, and allow it to circulate.

[0020] Step S9: The formed membrane is sent into an oven for aging treatment using a membrane aging fixture;

[0021] Step S10: Inspect the diaphragm after aging to confirm that there are no abnormalities such as pits, wrinkles, warping, or cracks.

[0022] Preferably, in step S2, the surface of the diaphragm is inspected according to the requirement that there are no scratches, indentations, pits, or wrinkles on the surface.

[0023] Preferably, in step S3, the membrane is soaked in degreasing agent HT-2 for more than 30 minutes. After soaking, the membrane surface is wiped with anhydrous ethanol. After wiping, the surface quality of the membrane is screened again to ensure that there is no excess grease, metal or non-metal on the surface.

[0024] In step S5, the membrane is soaked in degreasing agent HT-2 for more than 30 minutes. After soaking, the membrane surface is wiped with anhydrous ethanol. After wiping, the membrane surface quality is screened again to ensure that there is no grease, metal or non-metal residue on the surface. The membrane is then wrapped with clean white cotton paper.

[0025] Preferably, in step S4, the diaphragm is placed in the diaphragm machining fixture and clamped using bolts; after the diaphragm is clamped, it is mounted on a lathe and the diaphragm machining fixture is clamped; the inner hole and outer circle of the diaphragm are machined on a lathe, and the diaphragm machining fixture is machined together during the machining process.

[0026] Preferably, in step S6, the diaphragm is loaded into the molding fixture, compressed air is introduced for test pressing, and after the test pressing dimensions are qualified, the test pressing pressure, holding time, and fixture tightening torque parameters are recorded; wherein, the machined diaphragm is placed in the diaphragm installation position of the lower mold and pressed with a clamping block, the lower mold is placed into the upper mold, and then the upper mold and the lower mold as a whole are placed into the clamping fixture and pressed with a push rod, compressed air is introduced through the air inlet, and pressure is held for test pressing; the position and size of the corrugations are guaranteed by the mold.

[0027] Preferably, in step S7, the diaphragm is formally formed according to the recorded parameters of tooling tightening torque, inflation pressure, and holding time in the test molding record. During production, the surface quality of the diaphragm is checked for scratches, dents, and excess metal or non-metal. After forming, each piece is individually packaged with cotton paper, placed in a paper bag, and circulated.

[0028] Preferably, in step S9, the diaphragm aging fixture is cleaned to ensure that there are no metal or non-metal foreign objects in the fixture; the formed diaphragm is placed into the diaphragm aging fixture, each aging fixture having concave and convex parts that match the corrugation size of the diaphragm; the diaphragm is placed on a single aging fixture so that the corrugation of the diaphragm coincides with the concave and convex parts of the single aging fixture; the bolts are tightened and lightly pressed; the diaphragm is placed in an oven for heat preservation and air cooling to complete the aging treatment.

[0029] Preferably, in step S10, during the inspection of the diaphragm after aging, the inner circle of the central hole is smooth and free of burrs, the thickness of the diaphragm around the central hole is measured and recorded, and the thickness range of the entire batch of diaphragms is recorded; the appearance of the diaphragm is inspected using a magnifying glass with a light source.

[0030] Preferably, it is for a corrugated diaphragm of a launch vehicle valve with a thickness of 0.05 mm;

[0031] In step S1, the steel strip is selected with an elongation δ5 ≥ 8% and a tensile strength σ b ≥860MPa, yield strength ≥515MPa, the steel strip surface is free of scratches, pits, wrinkles, corrosion spots, and metallic and non-metallic indentations.

[0032] In step S2, when cutting the steel strip, each piece is cut to 55mm × 55mm, and the cut film is circular. The thickness of materials measured by a micrometer should be within 0.05 mm ± 0.01 mm;

[0033] In step S4, the inner hole of the diaphragm is machined using a lathe. The inner hole must be free of burrs and flanges. After machining the inner hole, remove the bolts from the diaphragm machining fixture, install the ejector pin from the diaphragm machining fixture, and then machine the outer diameter. The outer circle must be free of burrs and flanging. The diaphragm machining tooling is machined together with the diaphragm during the machining process.

[0034] In step S7, the forming fixture is wiped with anhydrous ethanol and blown off with compressed air once every 10 films are formed.

[0035] In step S10, the thickness of the diaphragm around the central hole is measured and recorded to be no less than 0.038 mm.

[0036] According to the present invention, a diaphragm is prepared by the forming method of the valve corrugated diaphragm described above.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] This invention is based on the key characteristics of valve bellows diaphragms, including the tightening torque of the diaphragm forming tooling, the pressure of the test forming, and the pressure holding. The production process includes raw material screening, blanking, cleaning and screening, machining, test forming, forming, aging, and inspection. This method effectively improves the production qualification rate of bellows diaphragms and has important engineering application value. Attached Figure Description

[0039] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0040] Figure 1 This is a diagram of the original steel strip in an embodiment of the present invention;

[0041] Figure 2 This is a diagram showing the approximate shape of the membrane being cut according to an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of lathe machining of an inner hole according to an embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of lathe machining of the outer diameter according to an embodiment of the present invention;

[0044] Figure 5 This is a schematic diagram illustrating the molding process of an embodiment of the present invention;

[0045] Figure 6 This is a typical corrugated diaphragm diagram according to an embodiment of the present invention;

[0046] Figure 7 for Figure 6 Cross-sectional view;

[0047] Figure 8 This is a schematic diagram illustrating the aging process in an embodiment of the present invention;

[0048] Figure 9 This is a flowchart of the precision forming method for the valve bellows diaphragm of the present invention.

[0049] The diagram shows:

[0050] Detailed Implementation

[0051] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0052] This invention, based on the key characteristics of valve bellows diaphragms, and considering methods such as raw material selection, pressure testing and molding parameters, and aging, solves the technical problem of how to improve the yield rate of bellows diaphragms. Specific implementation methods are as follows: Figures 1 to 8 As shown, the complete flowchart is as follows: Figure 9 As shown, the preferred embodiment of the present invention provides a precision molding method for a valve bellows diaphragm with a thickness of 0.05 mm, which includes the following steps:

[0053] 1) Protection of material surface quality: Due to the strict requirements on the surface quality of raw materials regarding the corrugation size and air leakage of the diaphragm, there must be no scratches, pits, or wrinkles. Therefore, raw materials must be screened, and qualified raw materials must be protected during the molding process. Raw material screening: The elongation, tensile strength, and yield strength of the steel strip material should meet the corresponding requirements; the steel strip selected should have a tensile strength σ b≥860MPa, elongation δ5≥8%, yield strength≥515MPa, the surface of the steel strip should be free of scratches, pits, wrinkles, corrosion spots, and metallic and non-metallic indentations.

[0054] 2) Material Cutting and Screening: Based on the diaphragm dimensions specified in the drawing, use a diaphragm cutting fixture to cut the diaphragm to a certain size. During cutting, visually inspect the diaphragm surface; it must be free of scratches, indentations, dents, wrinkles, and other defects. Specifically, cut out the approximate shape of the diaphragm and trim the original steel strip as follows: Figure 1 As shown, each piece is cut to 55mm x 55mm, and the cut film pieces are as close to a circle as possible. like Figure 2 The surface should be inspected and free from scratches, indentations, dents, wrinkles, and other defects. The material thickness measured with a micrometer should be within 0.05mm ± 0.01mm.

[0055] 3) Cleaning and screening: Soak the membrane in a degreasing agent (HT-2) for at least 30 minutes. After soaking, wipe the membrane surface with anhydrous ethanol. After wiping, screen the membrane surface again to ensure that there is no grease, metal, or non-metallic residue on the surface.

[0056] 4) Vehicle: such as Figure 3 Place the wiped diaphragm 100 into the diaphragm machining fixture 200 and tighten it with bolts, taking care to protect the diaphragm surface and preventing any foreign objects from entering during the process. After the diaphragm is clamped, mount it onto the lathe and tighten the fixture. Machin the inner hole of the diaphragm using a lathe. The inner hole must be free of burrs and flanges, such as Figure 3 After machining the inner hole, remove the bolts from the diaphragm machining fixture 200, install the push rod from the diaphragm machining fixture 200, and then machine the outer diameter. like Figure 4 The outer circle must be free of burrs and flanges, and the diaphragm machining tooling is machined together during the machining process.

[0057] 5) Second cleaning and screening: Soak the membrane again in degreasing agent (HT-2) for at least 30 minutes. After soaking, wipe the membrane surface with anhydrous ethanol. Confirm that there is no coolant, metal shavings, or other residue on the membrane surface. After wiping, screen the membrane surface quality again to ensure that there is no grease, metal, or non-metal residue on the surface; then wrap it in clean white cotton paper.

[0058] 6) Pressure Testing: After wiping, the diaphragm is placed into the forming fixture, and compressed air is introduced for pressure testing. Once the dimensions are within acceptable limits, important parameters such as the pressure test and holding time are recorded. Figure 5The machined diaphragm is placed in the diaphragm mounting position 6 of the lower mold 2 and tightened using the clamping block 5. The lower mold 2 is then placed into the upper mold 3, and the entire assembly of the upper mold 3 and lower mold 2 is placed into the clamping fixture 1 and tightened using the ejector rod 7. The tightening torque is 180 N·m. Compressed air is introduced through the air inlet 4 at approximately 7 MPa, and pressure is maintained for 60 seconds for test pressing. After the test pressing, the diaphragm dimensions are measured: R1.6; R1; lower limit 0.3~0.4; the position and size of the corrugations are guaranteed by the mold. If R1.6 does not meet the requirements, the pressure is finely adjusted in increments of 0.5 MPa. If the size is too large, the filling pressure is reduced; conversely, the filling pressure is increased. After the test pressing dimensions are qualified, important parameters such as the tightening torque of the fixture, the test pressure, and the holding time are recorded.

[0059] 7) Molding: Following the recorded parameters from the trial molding, such as tooling tightening torque, inflation pressure, and holding time, begin the formal molding of the diaphragm. During production, check the diaphragm surface for scratches, dents, and any metallic or non-metallic foreign matter. The pressed corrugated diaphragm should be... Figure 6 As shown, the cross-section is as follows Figure 7 As shown. After molding, each piece is individually packaged with cotton paper, placed in a paper bag, and carried around to prevent scratches; every 10 pieces are wiped with anhydrous ethanol and the molding fixture is blown off with compressed air once.

[0060] 8) Inspection: Inspect the dimensions of the molded film: R1.6; R1; lower limit 0.3~0.4; the position and size of the corrugations are guaranteed by the mold. After inspection, each piece is individually packaged with cotton paper, placed in a paper bag, and carried around to prevent scratches.

[0061] 9) Aging: After molding, the diaphragm is placed in an oven for aging treatment using a diaphragm aging fixture. Specifically, the aging fixture is cleaned to ensure it is free of any metallic or non-metallic foreign matter. The molded diaphragm is then loaded into the aging fixture, such as... Figure 8 Each aging fixture has recesses and protrusions that match the corrugation size of the diaphragm 100. The diaphragm 100 is placed on a single aging fixture 200 so that the corrugations of the diaphragm 100 coincide with the recesses and protrusions of the single aging fixture 200. Ten aging fixtures 200 can be used at a time to assemble nine corrugated diaphragms 100. Tighten the bolts and press lightly, place in an oven at 160℃, keep warm for 48 hours, and air cool to complete the aging treatment.

[0062] 10) Inspection: Inspect the diaphragms after aging to confirm that they are free from abnormalities such as pits, wrinkles, warping, and cracks. Specifically, during the inspection of the diaphragms after aging, the inner circle of the R4 center hole should be smooth and free of burrs. The thickness of the diaphragm around the center hole should be measured and recorded as not less than 0.038 mm. Record the thickness range of the entire batch of diaphragms. Use a 5x magnifying glass with a light source to inspect the appearance of the diaphragms. Note: The diaphragm surface should be free from abnormalities such as pits, wrinkles, warping, and cracks.

[0063] Among these requirements, the raw material properties for each batch of products must meet certain technical specifications. Before each batch of production, the pressure of the compressed air, the holding time, and the tightening torque of the tooling are key indicators that must be determined through pressure testing. During the formal production process, all parameters must be kept consistent with the parameters determined in the pressure testing. Before machining, molding, and aging, the surface quality of the diaphragm must be confirmed to be free of foreign matter.

[0064] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0065] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for forming a valve corrugated diaphragm, characterized in that, include: Step S1: Select raw materials based on the elongation, tensile strength, and yield strength of the steel strip material; Step S2: According to the diaphragm size, use a diaphragm cutting tool to cut and cut the material to form a diaphragm; Step S3: Perform the first cleaning and screening of the membrane sheets; Step S4: Machin the diaphragm using a lathe; Step S5: Perform a second cleaning and screening of the membrane sheet; Step S6: Perform a test molding and record the test parameters; Step S7: Mold the model according to the parameters recorded in the test molding record; Step S8: Inspect the dimensions of the formed film. After inspection, package each piece individually with cotton paper, place each piece in a paper bag, and allow it to circulate. Step S9: The formed membrane is sent into an oven for aging treatment using a membrane aging fixture; Step S10: Inspect the diaphragm after aging to confirm that there are no abnormalities such as pits, wrinkles, warping, or cracks. For a 0.05mm thick corrugated diaphragm valve in a launch vehicle; In step S1, the steel strip is selected with an elongation rate of... 5≥8%, tensile strength ≥860MPa, yield strength ≥515MPa, the steel strip surface is free of scratches, pits, wrinkles, corrosion spots, and metallic and non-metallic indentations; In step S2, when cutting the steel strip, each piece is cut to 55mm × 55mm, and the cut film is circular.

55. The thickness of materials measured by a micrometer should meet the requirement of 0.05mm ± 0.01mm; In step S4, the inner hole of the diaphragm is machined using a lathe. The inner hole must be free of burrs and flanges. After machining the inner hole, remove the bolts from the diaphragm machining fixture, install the ejector pin from the diaphragm machining fixture, and then machine the outer diameter. The outer circle must be free of burrs and flanges, and the diaphragm machining tooling must be machined together during the machining process. In step S7, the forming fixture is wiped with anhydrous ethanol and blown off with compressed air once every 10 films are formed. In step S10, the thickness of the diaphragm around the central hole is measured and recorded to be no less than 0.038 mm.

2. The method for forming a valve corrugated diaphragm according to claim 1, characterized in that, In step S2, the surface of the diaphragm is inspected according to the requirement that there are no scratches, indentations, pits, or wrinkles on the surface.

3. The method for forming a valve corrugated diaphragm according to claim 1, characterized in that, In step S3, the membrane is soaked in degreasing agent HT-2 for more than 30 minutes. After soaking, the membrane surface is wiped with anhydrous ethanol. After wiping, the membrane surface quality is screened again to ensure that there is no excess grease, metal or non-metal on the surface. In step S5, the membrane is soaked in degreasing agent HT-2 for more than 30 minutes. After soaking, the membrane surface is wiped with anhydrous ethanol. After wiping, the membrane surface quality is screened again to ensure that there is no grease, metal or non-metal residue on the surface. The membrane is then wrapped with clean white cotton paper.

4. The method for forming a valve corrugated diaphragm according to claim 1, characterized in that, In step S4, the diaphragm is placed in the diaphragm machining fixture and clamped with bolts; after the diaphragm is clamped, it is mounted on the lathe and the diaphragm machining fixture is clamped; the inner hole and outer circle of the diaphragm are machined on the lathe, and the diaphragm machining fixture is machined together during the machining process.

5. The method for forming a valve corrugated diaphragm according to claim 1, characterized in that, In step S6, the diaphragm is loaded into the molding fixture, compressed air is introduced for test pressing, and after the test pressing dimensions are qualified, the test pressing pressure, holding time, and fixture tightening torque parameters are recorded. Specifically, the machined diaphragm is placed in the diaphragm installation position of the lower mold and pressed with a clamping block. The lower mold is placed into the upper mold, and then the upper and lower molds are placed into the clamping fixture and pressed with a push rod. Compressed air is introduced through the air inlet and pressure is maintained for test pressing. The position and dimensions of the corrugations are guaranteed by the mold.

6. The method for forming a valve corrugated diaphragm according to claim 1, characterized in that, In step S7, the diaphragm is formally formed according to the recorded parameters of tooling tightening torque, inflation pressure, and holding time in the test molding record. During production, the surface quality of the diaphragm is checked for scratches, dents, and excess metal or non-metal. After forming, each piece is individually packaged with cotton paper, placed in a paper bag, and circulated.

7. The method for forming a valve corrugated diaphragm according to claim 1, characterized in that, In step S9, the aging fixture is cleaned to ensure that there are no metal or non-metal foreign objects in the fixture; the formed diaphragm is placed into the aging fixture, each aging fixture has concave and convex parts that match the corrugation size of the diaphragm; the diaphragm is placed on a single aging fixture so that the corrugation of the diaphragm coincides with the concave and convex parts of the single aging fixture; the bolts are tightened and lightly pressed; the aging treatment is completed by placing it in an oven for heat preservation and air cooling.

8. The method for forming a valve corrugated diaphragm according to claim 1, characterized in that, In step S10, the membrane after aging is inspected. The inner circle of the central hole is smooth and free of burrs. The thickness of the membrane around the central hole is measured and recorded, and the thickness range of the entire batch of membranes is recorded. The appearance of the membrane is inspected using a magnifying glass with a light source.

9. A diaphragm, characterized in that, The valve bellows diaphragm is prepared using the molding method described in any one of claims 1 to 8.

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