Flange assembly, multilayer bellows mechanical property release tooling and method

Abstract

This invention provides a flange assembly, a tooling and method for releasing the mechanical properties of a multi-layer corrugated pipe, wherein the flange assembly includes: a flange, a clamping plate, a retaining ring, and bolts; by engaging the retaining ring with the flange flange, the straight section of the corrugated pipe is suspended and does not participate in compression, avoiding the defect of the first wave surface sinking due to the compression force surface first contacting the end face of the straight section of the corrugated pipe; the outer edge of the clamping plate fits against the inner wall of the corrugation crest of the corrugated pipe, supporting the first wave on both sides of the corrugated pipe, effectively preventing the first wave at both ends of the corrugated pipe from detaching from the flange assembly, so as to complete the subsequent mechanical property release steps of the multi-layer corrugated pipe; the multi-layer corrugated pipe mechanical property release method realizes the improvement of the consistency of the stress state between the layers of the multi-layer corrugated pipe and the release of mechanical properties, and the matching tooling makes the operation simple and efficient, effectively protecting the appearance quality of the corrugated pipe.

Description

Technical Field

[0001] This invention relates to apparatus and methods in the field of pipe forming technology, specifically to a flange assembly, a tooling and method for releasing the mechanical properties of a multi-layer corrugated pipe. Background Technology

[0002] Multi-layered corrugated pipes are widely used in aerospace propulsion systems. When the number of corrugated pipe layers exceeds five, the material distribution and stress state between some layers are not completely consistent circumferentially after forming. Direct use of untreated corrugated pipes can lead to planar instability and column instability under conditions such as displacement fatigue and pressure, even with small displacements and low pressures. This affects the performance and service life of the corrugated pipe, failing to meet design requirements. Therefore, compression and tension methods are necessary to release the mechanical properties of the corrugated pipe.

[0003] When the number of bellows layers is large, the stiffness is high, making manual compression and stretching unsuitable due to low operational efficiency. Furthermore, directly compressing both ends of the bellows without protective devices can easily lead to indentation defects on the first wave end faces, affecting the bellows' performance.

[0004] A Chinese patent with publication number CN215000029U discloses a bellows flange joint, which includes a bellows body. A front joint and a rear joint are respectively provided at both ends of the bellows body. Both the front joint and the rear joint include a flange. The outer side of the flange in the front joint has a groove. The outer side of the flange in the rear joint has a connecting block fixed. The inner side of the flange has a coaxial connecting pipe and a fixing pipe fixed from the inside to the outside. The outer wall of the port at the other end of the fixing pipe has a number of connecting grooves distributed in a circular array.

[0005] However, when the bellows flange joint disclosed in CN215000029U is used to connect a hydraulic press for compression and tensioning of the bellows, it still results in concave defects at both ends of the first wave face, affecting the performance of the bellows. Its clamping blocks are narrow, with a small contact area with the bellows, making them prone to damage during compression and tensioning. Furthermore, after the bellows flange joint of CN215000029U is installed on the bellows body, using conventional compression and tensioning methods to release the stress in the multi-layered bellows results in low consistency of stress state between layers, leading to poor mechanical property release. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a flange assembly, a tooling and method for releasing the mechanical properties of a multi-layer bellows.

[0007] A flange assembly according to the present invention includes: a flange, a retaining plate, a retaining ring, and bolts; At least three of the clamping plates are respectively bolted to the top of the flange, and the clamping plates can extend or retract radially along the plane in which the clamping plates are located; The retaining ring is disposed on the outside of the straight section of the bellows, and a straight section channel is formed between the retaining ring and the flange. When the card plate is in the retracted state, the outer envelope diameter of the card plate is smaller than the inner diameter of the trough of the bellows; When the card plate is in the extended state, the outer envelope diameter of the card plate is not greater than the inner diameter of the corrugated pipe crest.

[0008] Preferably, the bolt holes on the flange are oblong holes.

[0009] Preferably, the thickness of the card plate is less than the crest width of the corrugated pipe.

[0010] Preferably, the flange is an aluminum alloy flange.

[0011] Preferably, the card plate has rounded corners around its perimeter.

[0012] Preferably, rubber sheets are attached to the upper and lower surfaces of the card plate.

[0013] Preferably, the height of the retaining ring is greater than the height of the straight section of the bellows, and the width of the retaining ring exceeds the width of the corrugated surface of the bellows.

[0014] According to the present invention, a multi-layer bellows mechanical property release tooling is provided, which adopts the flange assembly described in any one of the above-mentioned methods and further includes a hydraulic assembly; The two flange assemblies are respectively installed at both ends of the bellows, and the flange assemblies are connected to the hydraulic press, which is used to compress or stretch the bellows.

[0015] According to the present invention, a method for releasing the mechanical properties of a multi-layer corrugated pipe is provided, employing the aforementioned multi-layer corrugated pipe mechanical property release fixture, comprising: S1, the hydraulic assembly compresses the bellows until the crests fit together; S2, the hydraulic components pull the bellows up to a height exceeding the maximum tensile working height; S3, repeat S1 to S2 at least once.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention uses a flange assembly with a retaining ring and a retaining plate bolted to the flange. The retaining ring engages with the flange flange, allowing the straight section of the bellows to be suspended and not participate in compression. This avoids the defect of the first wave surface sinking due to the compression force surface first contacting the end face of the straight section of the bellows. The outer edge of the retaining plate fits against the inner wall of the bellows crest, supporting the first wave on both sides of the bellows, thus effectively preventing the first wave at both ends of the bellows from detaching from the flange assembly, so as to complete the subsequent mechanical property release steps of the multi-layer bellows. Furthermore, the contact area between the retaining plate and the bellows is large, and the pressure exerted by the retaining plate on the bellows is small during the tensile and compressive processes of the bellows, thereby protecting the bellows from damage.

[0017] 2. This invention achieves consistent stress state between layers of multi-layer corrugated pipe by adopting a mechanical property release method, thereby improving the release of its mechanical properties. Furthermore, the accompanying tooling simplifies and simplifies the operation process, effectively protecting the appearance quality of the corrugated pipe. Attached Figure Description

[0018] 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: Figure 1 This is a schematic diagram illustrating the compression and tension states of the bellows, which are the main features of this invention. Figure 2 This is a schematic diagram illustrating the structure of the card plate in its retracted and extended states, which is the main feature of this invention. Figure 3 This is a top view showing the retracted and extended states of the card plate, which is the main feature of this invention.

[0019] The diagram shows: 1. Flange; 2. Clamping plate; 3. Snap ring; 4. Bolt. Detailed Implementation

[0020] 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.

[0021] like Figure 1 and Figure 2 As shown, a flange assembly provided by the present invention is characterized by comprising: a flange 1, a retaining plate 2, a retaining ring 3, and bolts 4.

[0022] Flange 1 is the base of the flange assembly.

[0023] The card plate 2 has a fan-shaped structure, and the outer edge size of the card plate 2 is consistent with the shape and size of the inside of the corrugated pipe crest.

[0024] At least three clamping plates 2 are connected to the top of the flange 1 by bolts 4. The bolts 4 are of moderate tightness, so that the clamping plates 2 can extend or retract radially along the plane of the clamping plates 2.

[0025] The retaining ring 3 is located on the outside of the straight section of the bellows, that is, the retaining ring 3 is located on the side of the first wave of the bellows near the end face.

[0026] The retaining ring 3 is located on the outside of the flange 1. A straight pipe section channel is formed between the retaining ring 3 and the flange 1. The straight pipe section of the bellows is set between the outer side of the flange 1 and the retaining ring 3.

[0027] When the clamping plate 2 is in the retracted state, the overall outer envelope diameter of the clamping plate 2 is smaller than the inner diameter of the corrugated trough of the bellows. This allows the flange 1, on which the clamping plate 2 is installed, to be smoothly installed into the bellows.

[0028] When the clamping plate 2 is in the extended state, the outer envelope diameter of the clamping plate 2 is not greater than the inner diameter of the corrugated pipe crest, and the outer edge of the clamping plate 2 is in contact with the inner wall of the corrugated pipe crest.

[0029] When installing the flange assembly onto the end face of the bellows, first, fit the retaining ring 3 onto the outside of the straight section of the bellows. Then, retract the retaining plate 2 on the flange 1 radially using the bolts 4, and install the flange with the retaining plate 2 onto the end face of the bellows. At this point, the plane of the retaining plate 2 is on the same plane as the first wave of the bellows, the retaining plate 2 extends radially, and the outer edge of the retaining plate 2 fits against the inner wall of the bellows crest, completing the installation of the flange assembly.

[0030] When it is necessary to remove the flange assembly from the end face of the bellows, the clamping plate 2 is retracted radially, the flange with the clamping plate 2 installed is removed, and then the retaining ring 3 is removed, thus completing the disassembly of the entire flange assembly.

[0031] The flange assembly is equipped with a retaining ring 3 and a retaining plate 2 connected to the flange 1 by bolts 4. The retaining ring 3 engages with the flange of the flange 1, allowing the straight section of the bellows to be suspended and not involved in compression. This avoids the defect of the first wave surface sinking due to the compression force surface first contacting the end face of the straight section of the bellows.

[0032] When the clamping plate 2 is in the retracted state, the flange 1 with the clamping plate 2 installed can be smoothly installed into the bellows. When the clamping plate 2 extends out, the outer edge of the clamping plate 2 fits against the inner wall of the bellows crest, supporting the first wave on both sides of the bellows. This effectively prevents the first wave at both ends of the bellows from detaching from the flange assembly when the bellows is stretched or compressed, so as to complete the subsequent mechanical property release steps of the multi-layer bellows.

[0033] In some feasible implementations, the bolt holes on the flange 1 are oblong holes, and the clamping plate 2 is provided with threaded holes. The bolts 4 are connected through the oblong holes on the flange 1 and the threaded holes on the clamping plate 2. The tightness of the bolts 4 is moderate, so that the clamping plate 2 can extend or retract radially.

[0034] In some feasible implementations, the thickness of the clamping plate 2 is less than the crest width of the bellows. This ensures that when the clamping plate 2 extends, it can smoothly insert into the crest.

[0035] In some feasible implementations, flange 1 is an aluminum alloy flange. The material of flange 1 is selected from lightweight materials such as aluminum alloy, which facilitates manual handling for installation and disassembly.

[0036] In some feasible implementations, the corners of the clamping plate 2 are rounded to prevent the corners of the clamping plate 2 from damaging the inner surface of the bellows during compression and stretching.

[0037] In some feasible implementations, rubber sheets are attached to the upper and lower surfaces of the clamping plate 2, respectively. This prevents the clamping plate 2 from damaging the inner surface of the bellows during compression and stretching.

[0038] In some feasible implementations, the height of the retaining ring 3 is greater than the height of the straight section of the bellows, and the width of the retaining ring 3 exceeds the width of the corrugated surface of the bellows. Because the height of the retaining ring 3 is greater than the height of the straight section of the bellows, the straight section of the bellows is not subjected to force when the bellows is compressed. Furthermore, because the width of the retaining ring 3 exceeds the width of the corrugated surface of the bellows, the corrugated surface of the bellows always has a force-bearing surface when the bellows is compressed. This prevents the compression force-bearing surface from first contacting the end face of the straight section of the bellows, thus avoiding the defect of initial corrugated surface depression.

[0039] The present invention also provides a tooling for releasing the mechanical properties of a multi-layer bellows, employing a flange assembly as described above, and further comprising a hydraulic assembly. Two flange assemblies are respectively installed at both ends of the bellows, and the flange assemblies are connected to a hydraulic press, which is used to compress or stretch the bellows. Specifically, the flange assemblies at both ends are fixed to the hydraulic press by pressure plates.

[0040] This invention also provides a method for releasing the mechanical properties of a multi-layer corrugated pipe, employing the aforementioned multi-layer corrugated pipe mechanical property release fixture, comprising: S1, the hydraulic assembly compresses the bellows until the crests fit together; S2, the hydraulic components pull the bellows up to a height exceeding the maximum tensile working height; S3, repeat S1 to S2 at least once.

[0041] In some feasible implementations, the corrugated pipe has a 7-layer structure, with a single layer wall thickness of 0.5mm, a nominal diameter of φ450mm, an outer diameter of φ508mm, and a straight pipe section height of 15mm at both ends.

[0042] To release the mechanical properties of the bellows, select a flange assembly, which includes: flange 1, clamping plate 2, retaining ring 3, and bolts 4.

[0043] Four clamping plates 2 are connected to flange 1, each clamping plate 2 is connected to flange 1 by three bolts 4. Flange 1 has a waist-shaped hole, and clamping plate 2 has a threaded hole. The bolts 4 are tightened to a moderate degree, allowing clamping plates 2 to extend and retract smoothly. The outer arc of clamping plate 2 is set to R248mm, so that clamping plate 2 is close to the crest of the bellows when extended. The spacing between clamping plates 2 when extended is set to 55mm. When clamping plates 2 are retracted, the outer envelope contour is smaller than the bellows diameter φ450mm, so that clamping plates 2 can be smoothly inserted into the bellows. The thickness of clamping plate 2 is set to 10mm, and smooth rounded chamfers are set around its perimeter. The height of clamping ring 3 is set to 20mm, which is higher than the height of the straight pipe sections at both ends of the bellows. The outer diameter of clamping ring 3 is set to φ505mm, which extends beyond the corrugated area at both ends of the bellows.

[0044] Fit the retaining ring 3 onto one end of the bellows. Retract the four retaining plates 4 on flange 1 radially and insert them into the bellows. Then extend the four retaining plates 4 radially. Assemble the other end of the bellows in the same way. After assembling the fixtures at both ends of the bellows, fix the flanges 1 at both ends of the fixtures to the hydraulic press using pressure plates.

[0045] The steps for releasing the mechanical properties of the bellows are as follows: S11, Corrugated pipe compression: Control the downward movement of the hydraulic press slide to compress the corrugated pipe crests together. For a 7-layer corrugated pipe, the interlayer stress state is complex. During the first compression, some corrugations tilt and surface instability occurs.

[0046] S12, Corrugated pipe stretching: The hydraulic press moves upward to pull the corrugated pipe up to a stretching state of 70mm, which exceeds the maximum stretching condition of the corrugated pipe by 50mm.

[0047] S13. Repeat several times: Repeat the tension and compression twice. At this time, the stress state between the corrugated pipe layers tends to be uniform. No instability occurs during tension and compression, and the mechanical properties of the multi-layer corrugated pipe are released.

[0048] After the mechanical properties of the bellows have been released, the flange assembly is disassembled. The hydraulic press is used to position the bellows to the required length. The pressure plate connecting the tooling and the hydraulic press is removed. The four retaining plates 4 on flange 1 are retracted radially and removed, and the retaining ring 3 is removed. The other end of the bellows is removed in the same way.

[0049] A method for releasing the mechanical properties of multi-layer corrugated pipes is adopted to improve the consistency of stress state between layers and release mechanical properties. With the help of matching tooling, the operation process is simple, efficient and effective in protecting the appearance quality of the corrugated pipes.

[0050] 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.

[0051] 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 flange assembly, characterized in that, include: Flange (1), clamping plate (2), retaining ring (3), bolt (4); At least three of the aforementioned clamping plates (2) are respectively connected to the upper part of the flange (1) by bolts (4), and the clamping plates (2) can extend or retract radially along the plane where the clamping plates (2) are located; The retaining ring (3) is disposed on the outside of the straight pipe section of the bellows, and a straight pipe section channel is formed between the retaining ring (3) and the flange (1); When the card plate (2) is in the retracted state, the outer envelope diameter of the card plate (2) is smaller than the inner diameter of the corrugated trough; When the card plate (2) is in the extended state, the outer envelope diameter of the card plate (2) is not greater than the inner diameter of the corrugated pipe crest.

2. The flange assembly as claimed in claim 1, characterized in that, The bolt holes on the flange (1) are waist-shaped holes.

3. The flange assembly as described in claim 1, characterized in that, The thickness of the card plate (2) is less than the crest width of the corrugated pipe.

4. The flange assembly as claimed in claim 1, characterized in that, The flange (1) is an aluminum alloy flange.

5. The flange assembly as claimed in claim 1, characterized in that, The card plate (2) has rounded corners around its perimeter.

6. The flange assembly as claimed in claim 1, characterized in that, Rubber plates are attached to the upper and lower surfaces of the card plate (2).

7. The flange assembly as claimed in claim 1, characterized in that, The height of the retaining ring (3) is greater than the height of the straight section of the bellows, and the width of the retaining ring (3) exceeds the width of the corrugated surface of the bellows.

8. A tooling for releasing the mechanical properties of a multi-layer corrugated pipe, characterized in that, The flange assembly using any one of claims 1 to 7 further includes a hydraulic assembly; The two flange assemblies are respectively installed at both ends of the bellows, and the flange assemblies are connected to the hydraulic press, which is used to compress or stretch the bellows.

9. A method for releasing the mechanical properties of a multi-layer corrugated pipe, characterized in that, The multi-layer corrugated pipe mechanical property release tooling as described in claim 8 includes: S1, the hydraulic assembly compresses the bellows until the crests fit together; S2, the hydraulic components pull the bellows up to a height exceeding the maximum tensile working height; S3, repeat S1 to S2 at least once.

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