Large-diameter corrugated pipe precision forming die and process

Abstract

The application discloses a large-diameter corrugated pipe precision forming die and process, relates to the technical field of corrugated pipe dies, and comprises an upper die base, a lower die base and middle die pieces, the middle die pieces are provided in groups, the end portions of each group of middle die pieces are connected with hydraulic cylinders through connecting rods, the hydraulic cylinders are installed below the lower die base, guide columns are arranged on the lower die base, the upper ends of the guide columns are connected with the upper die base, the guide columns are provided in two, and the two guide columns are connected with the upper die base and the lower die base through guide sleeves. The large-diameter corrugated pipe precision forming die and process adopt the above structure, the position control mode of the die pieces is coordinately controlled through laser sensors, the peak position can be accurately detected, corrugated pipes with different wave heights can be formed, the adaptability is good, the position movement of the die pieces is realized through the control of the hydraulic cylinders, the die pieces are flexibly moved, the peak positions are consistent when the die is closed, the problem of low wave form precision of the corrugated pipe in the forming process is solved, the forming efficiency is improved, and the forming quality is ensured.

Description

Technical Field

[0001] This invention relates to the field of corrugated pipe mold technology, and in particular to a precision forming mold and process for large-diameter corrugated pipes. Background Technology

[0002] A corrugated pipe is a type of pipe with a corrugated cross-section. It is a core component for displacement compensation in heated and pressurized piping systems and equipment, and is widely used in aerospace, chemical, shipbuilding, and nuclear energy fields. Therefore, higher requirements are placed on the forming quality and manufacturing process of corrugated pipes.

[0003] The commonly used forming method for large-diameter corrugated pipes is hydroforming. Hydroforming is a simple process that can process large-diameter corrugated pipes with high corrugation heights. However, the quality of hydroforming corrugated pipes is affected by several process parameters, such as the internal pressure of the liquid medium and the dimensions of the pipe blank itself. Improper control of these factors can easily lead to defects such as wrinkling, uneven wall thickness, and cracking during hydroforming. Therefore, strict control of process parameters is necessary to ensure forming quality during the hydroforming process of corrugated pipes. The forming process of corrugated pipes can be roughly divided into a liquid filling and bulging stage and a pressure holding and mold closing stage. In the liquid filling and bulging stage, liquid is introduced into the pipe blank, and the liquid pressure is increased to a certain value. Under hydraulic pressure, the pipe blank is expanded, forming small-height bulges under the constraint of the mold plates. In the pressure holding and mold closing stage, the mold plates are pressed together by a hydraulic press, and the small bulges formed in the liquid filling and bulging stage are gradually flattened, forming the final corrugated shape. As can be seen from the above process, the shape of the small bulges formed during the liquid filling and bulging stage has a significant impact on the final waveform size, and the spacing between the various mold pieces is crucial to the shape of the small bulges. Therefore, controlling the spacing between the mold pieces is the key to controlling the precision of bellows hydroforming. In existing production processes, the spacing between each mold piece is pre-determined through trial and error, and the spacing is manually adjusted using shims. After liquid filling and bulging, the shims are removed before pressure holding and mold closing. Under this adjustment method, the spacing between the mold pieces is fixed and cannot be adjusted in real time with the height of the wave, making it difficult to guarantee the final waveform size accuracy. Moreover, manually adding or removing shims is labor-intensive and has low production efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a precision forming mold and process for large-diameter corrugated pipes, which solves the problems of inaccurate waveform control, high manual labor intensity and low efficiency in the existing forming process.

[0005] To achieve the above objectives, the present invention provides a precision forming mold and process for large-diameter corrugated pipes, including an upper mold base, a lower mold base, and intermediate mold pieces. Multiple sets of intermediate mold pieces are provided, and the end of each set of intermediate mold pieces is connected to a hydraulic cylinder via a connecting rod. The hydraulic cylinder is installed below the lower mold base. A guide post is provided on the lower mold base, and the upper end of the guide post is connected to the upper mold base. Two guide posts are provided, and both guide posts are connected to the upper mold base and the lower mold base via guide sleeves.

[0006] Preferably, a top mold plate is provided below the upper mold base, the top mold plate is connected to the tube blank, a rubber bladder is placed inside the tube blank, the lower end of the tube blank is connected to the bottom mold plate, and both the bottom mold plate and the top mold plate are connected to the lower mold base and the upper mold base by screws.

[0007] Preferably, the upper mold base is provided with a filling port, which is connected to the rubber bladder.

[0008] Preferably, the outer end of the tube blank is connected to a plurality of intermediate mold pieces, the plurality of intermediate mold pieces including an outer mold piece and an inner mold piece, the inner end of the inner mold piece is connected to the tube blank, the outer end of the inner mold piece is connected to the outer mold piece, and the outer mold piece and the inner mold piece are connected by connecting screws.

[0009] Preferably, the outer end of the outer mold plate is provided with a second mold connecting plate and a first mold connecting plate. The first mold connecting plate is connected to the guide post through the guide sleeve, and the second mold connecting plate is connected to the connecting rod.

[0010] Preferably, a laser sensor is provided at the upper end of the second mold connecting plate, and the second mold connecting plate is distributed at equal angles along the circumferential direction.

[0011] Preferably, the hydraulic cylinder is connected to the lower mold base via the connecting screw.

[0012] A precision forming process for large-diameter corrugated pipes includes the following steps:

[0013] Step 1: Assemble the mold and place the tube blank, place the rubber bladder and seal it;

[0014] Step 2: The rubber bladder is filled with liquid and pressurized, and the laser sensor controls the movement of the template;

[0015] Step 3: Maintain pressure inside the bladder and press the hydraulic cylinder mold together.

[0016] Preferably, in step two, the tube blank forms a wavy shape under the action of the rubber bladder filling with liquid. The laser sensor detects the position of the wave peak and controls the hydraulic cylinder to lift and lower based on the detection result, so that the position of the wave peak remains consistent.

[0017] Preferably, in step three, the hydraulic cylinder provides a small back pressure, and as the mold pieces move down, the pressure is gradually released, and the individual mold pieces are pressed together, the small drum wave is flattened, and the final waveform is formed.

[0018] Therefore, the present invention, which employs the above-described structure, provides a precision forming mold and process for large-diameter corrugated pipes, and has the following beneficial effects:

[0019] (1) The present invention designs a laser sensor coordinated control module position control method, which can accurately detect the peak position and realize the position movement of the module through hydraulic cylinder control. The module can be moved flexibly to ensure that the peak position is consistent when the mold is closed, solve the problem of low accuracy of the middle wave shape in the corrugated tube forming, improve the forming efficiency, and at the same time ensure the forming quality.

[0020] (2) The present invention uses a laser sensor to coordinate and control the mold position device, which can form corrugated pipes with different wave heights. It has good applicability and ensures that each wave of the corrugated pipe can meet the forming requirements after the mold is closed, thus solving the problem of low accuracy of the middle wave in the corrugated pipe forming.

[0021] (3) The present invention controls the lifting and lowering of the mold pieces by hydraulic cylinder, which can replace the existing process of manually adjusting the height of the pads to adjust the spacing of the mold pieces. This greatly reduces the intensity of manual labor and improves production efficiency. After adjusting the position of the mold pieces, the mold can be closed directly. The process is simple, the production cycle is shortened, and the forming efficiency is improved.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a precision forming mold and process embodiment for a large-diameter corrugated pipe according to the present invention;

[0024] Figure 2 This is a cross-sectional view of a precision forming mold and process for a large-diameter corrugated pipe according to the present invention.

[0025] Figure 3 This is a schematic diagram of the guide post structure of a precision forming mold and process for a large-diameter corrugated pipe according to the present invention.

[0026] Figure 4 This is a diagram showing the mold structure during the liquid filling stage of this invention.

[0027] Figure 5 This is a diagram showing the mold structure during the pressure holding and mold closing stage of this invention.

[0028] Figure Labels

[0029] 1. Hydraulic cylinder; 2. Lower mold base; 3. Bottom mold plate; 4. Connecting rod; 5. Outer mold plate; 6. Inner mold plate; 7. Laser sensor; 8. Tube blank; 9. Top mold plate; 10. Upper mold base; 11. Rubber bladder; 12. Guide post; 13. Guide sleeve; 14. Filling port; 15. Screw; 16. Connecting screw; 17. Mold connecting plate one; 18. Mold connecting plate two. Detailed Implementation

[0030] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0032] Example

[0033] Please see Figure 1-5 This invention provides a precision forming mold and process for large-diameter corrugated pipes, including an upper mold base 10, a lower mold base 2, and intermediate mold pieces. Multiple sets of intermediate mold pieces are provided, with different numbers placed in the middle according to the required number of corrugated pipe waveforms. The end of each set of intermediate mold pieces is connected to a hydraulic cylinder 1 via a connecting rod 4, providing support for the mold piece. The hydraulic cylinder 1 is installed below the lower mold base 2 and connected to the lower mold base 2 via connecting screws 16. Two guide pillars 12 are provided on the lower mold base 2, with their upper ends connected to the upper mold base 10. Both guide pillars 12 are connected to the upper mold base 10 and the lower mold base 2 via guide sleeves 13. Guide sleeves are installed inside the upper mold base 10, lower mold base 2, and intermediate mold pieces. The guide sleeves 13 are pierced by the two guide pillars 12, guiding the movement of the mold piece.

[0034] A top mold plate 9 is provided below the upper mold base 10. The top mold plate 9 is connected to the tube blank 8. A rubber bladder 11 is placed inside the tube blank 8. The rubber bladder 11 can be filled with high-pressure liquid to perform hydraulic expansion of the tube blank 8. The lower end of the tube blank 8 is connected to the bottom mold plate 3. Both the bottom mold plate 3 and the top mold plate 9 are connected to the lower mold base 2 and the upper mold base 10 by screws 15. The top mold plate 9 and the bottom mold plate 3 play a role in fixing the tube blank 8.

[0035] The upper mold base 10 is provided with a liquid filling port 14, which is connected to the rubber bladder 11. Liquid is injected into the rubber bladder 11 through the liquid filling port 14, and the rubber bladder 11 gradually expands under the action of liquid pressure.

[0036] The outer end of the tube blank 8 is connected to multiple sets of intermediate mold plates, including an outer mold plate 5 and an inner mold plate 6. The inner end of the inner mold plate 6 is connected to the tube blank 8, and the outer end of the inner mold plate 6 is connected to the outer mold plate 5. The outer mold plate 5 and the inner mold plate 6 are connected by connecting screws 16, and multiple connecting screws 16 are provided. The outer end of the outer mold plate 5 is provided with a mold connecting plate 2 18 and a mold connecting plate 17. The mold connecting plate 17 is connected to the guide post 12 and is connected to the hydraulic cylinder 1 via a connecting rod 4. Each mold plate is supported by two hydraulic cylinders 1. The positions of the mold connecting plates 17 are evenly distributed along the circumference to ensure that the positions of the connecting rods 4 do not interfere with each other. A guide sleeve 13 is installed at the connection between the mold connecting plate 17 and the guide post 12 to guide the movement of the mold plate. The positions of the mold connecting plates 17 are in the same vertical direction. A laser sensor 7 is provided at the upper end of the mold connecting plate 17. The laser sensor 7 coordinates and controls the movement of the mold pieces. The laser sensor 7 adjusts the spacing between the mold pieces by controlling the upward or downward movement of the hydraulic cylinder 1.

[0037] The process route for manufacturing bellows using hydroforming is as follows:

[0038] 1) Press Figure 2 Assemble the mold and place the tube blank 8: Install the mold from bottom to top. The bottom mold plate 3 and the hydraulic cylinder 1 are connected to the lower mold base 2 by connecting screws 16. The outer mold plate 5 and the inner mold plate 6 are connected as a whole by connecting screws 16 and connected to the hydraulic cylinder 1 by connecting rod 4. The top mold plate 9 is connected to the upper mold base 10 by screws 15. The tube blank 8 is inserted into the expansion mold. The rubber bladder 11 is placed and sealed. The laser sensor 7 is installed above each outer mold plate 5. The lower mold base 2 and the upper mold base 10 are connected by guide post 12.

[0039] 2) The rubber bladder 11 is filled with liquid and pressurized, and the laser sensor 7 coordinates and controls the movement of the mold: Liquid is injected into the rubber bladder 11 through the filling port 14. The rubber bladder 11 gradually expands under the pressure of the liquid. When it expands to a certain extent, the tube blank 8 expands outward, forming a small bulge with a relatively small height under the constraint of the mold, such as... Figure 4As shown. During this process, the laser sensor 7 detects the position of the wave peak and uses the detection result as a feedback signal to control the hydraulic cylinder 1 to move up or down, thereby adjusting the spacing between the mold pieces. When the height of each small drum wave is consistent, the hydraulic cylinder 1 remains stationary.

[0040] 3) Maintaining pressure within the bladder and pressing the mold pieces together: Keeping the pressure in the rubber bladder 11 constant, under the pressure (F) of the hydraulic press, the upper mold base 10 moves downwards, pressing the mold pieces together. The small drum-like waves formed during the filling and pressurization stage are flattened, forming the final waveform, such as... Figure 5 As shown. During this process, hydraulic cylinder 1 provides a small back pressure, which is gradually released as the mold pieces move downwards, ensuring smooth movement of each mold piece.

[0041] Therefore, this invention provides a precision forming mold and process for large-diameter corrugated pipes using the aforementioned structure. This invention employs a laser sensor-coordinated control method for mold plate position control, which can accurately detect the wave crest position and control the mold plate position movement via a hydraulic cylinder. This flexible mold plate movement ensures consistent wave crest positions during mold closing, solving the problem of low accuracy in the middle wave pattern during corrugated pipe forming, improving forming efficiency, and ensuring forming quality. The laser sensor-coordinated control device for mold plate position control allows for the forming of corrugated pipes with different wave heights, offering good applicability and ensuring that each wave of the corrugated pipe meets forming requirements after mold closing, ultimately solving the problem of low accuracy in the middle wave pattern during corrugated pipe forming. Furthermore, this invention controls the lifting and lowering of the mold plate via a hydraulic cylinder, replacing the existing method of manually adjusting the mold plate spacing by adjusting the height of the shims. This significantly reduces manual labor intensity and improves production efficiency. After adjusting the mold plate position, mold closing can be performed directly, simplifying the process, shortening the production cycle, and improving forming efficiency.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A precision forming process for large-diameter corrugated pipes, characterized in that: A large-diameter corrugated pipe precision forming mold is adopted. The mold includes an upper mold base, a lower mold base, and intermediate mold pieces. Multiple sets of intermediate mold pieces are provided. The end of each set of intermediate mold pieces is connected to a hydraulic cylinder via a connecting rod. The hydraulic cylinder is installed below the lower mold base. A guide post is provided on the lower mold base. The upper end of the guide post is connected to the upper mold base. There are two guide posts. Both guide posts are connected to the upper mold base and the lower mold base via guide sleeves. A top mold plate is provided below the upper mold base, a tube blank is provided inside the top mold plate, a rubber bladder is placed inside the tube blank, and the lower end of the tube blank is connected to the bottom mold plate. The bottom mold plate and the top mold plate are both connected to the lower mold base and the upper mold base by screws. The upper mold base is provided with a liquid filling port, which is connected to the rubber bladder; The outer end of the tube blank is connected to a plurality of intermediate mold pieces, the plurality of intermediate mold pieces including an outer mold piece and an inner mold piece, the inner end of the inner mold piece is connected to the tube blank, the outer end of the inner mold piece is connected to the outer mold piece, and the outer mold piece and the inner mold piece are connected by connecting screws; The outer end of the outer mold plate is provided with a mold connecting plate 2 and a mold connecting plate 1. The mold connecting plate 1 is connected to the guide post through the guide sleeve, and the mold connecting plate 2 is connected to the connecting rod. A laser sensor is provided at the upper end of the second mold connecting plate, and the second mold connecting plate is distributed at equal angles along the circumferential direction; The process includes the following steps: Step 1: Assemble the mold and place the tube blank, place the rubber bladder and seal it; Step 2: The rubber bladder is inflated with liquid and pressurized, and the laser sensor coordinates and controls the movement of the template; Step 3: Maintain pressure inside the bladder and press the hydraulic cylinder mold together; In step two, the tube blank forms a bulge under the action of the rubber bladder filling with liquid. The laser sensor detects the position of the bulge peak and controls the hydraulic cylinder to lift and lower based on the detection result, so that the position of the bulge peak remains consistent.

2. The precision forming process for a large-diameter corrugated pipe according to claim 1, characterized in that: The hydraulic cylinder is connected to the lower mold base via the connecting screw.

3. The precision forming process for a large-diameter corrugated pipe according to claim 1, characterized in that: In step three, the hydraulic cylinder provides a small back pressure. As the mold pieces move down, the pressure is gradually released, and the individual mold pieces are pressed together, flattening the drum wave and forming the final waveform.

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