Pipe fitting welding positioning device based on special-shaped space position and integrated machining method

Abstract

The invention discloses an assembling, welding and positioning device for a fuel manifold assembly and an integrated machining method. The device comprises a bottom plate, a second positioning seat, a first positioning seat, a limiting seat and a plurality of supports, special-shaped space postures of a fuel main pipe and branch pipes are accurately locked through a three-stage cooperative positioning system, and the positioning precision reaches + / -0.02 mm. The method comprises the steps that reference positioning of a fuel main pipe and clamping of all branch pipes are sequentially completed in the device, a symmetric welding method combining brazing and argon arc welding is adopted for integrated welding, and limiting cooling is conducted in a clamp in the whole process so as to control deformation. High-precision and high-efficiency batch machining of the fuel manifold assembly is achieved, the production qualification rate is increased to 98%, and the single-piece machining time is shortened by 47.3%.

Description

Technical Field

[0001] This invention relates to the field of fuel pipeline assembly and processing technology, specifically to a fuel main pipe assembly-sub-pipe assembly welding and positioning device and integrated processing method based on irregular spatial position, applicable to fields such as aero-engines and marine power systems where the spatial position requirements of fuel pipelines are extremely high. Background Technology

[0002] As a crucial component of the engine, the fuel manifold assembly, with its main fuel line and branch lines, serves as the central hub for fuel delivery and distribution. The main fuel line precisely delivers fuel from the fuel supply source to each branch line, distributing stable pressure and flow rates to the combustion chamber. Performance parameters of the fuel manifold include flow rate, distribution, and injection direction. These three parameters directly affect the combustion efficiency and temperature field within the engine's combustion chamber. To maintain a uniform temperature field and prevent localized overheating that could cause erosion of downstream components, the precise spatial alignment of the main fuel line and branch lines is essential to ensure fuel supply efficiency and system safety.

[0003] A new fuel main assembly is manufactured by connecting an upper fuel main assembly and a lower fuel main assembly using tapered connectors and external nuts. The upper fuel main assembly is formed by combining 10 tee pipes and 10 fuel branch pipes with tapered connectors at both ends of the upper fuel main assembly. The manufacturing process involves both brazing and argon arc welding. The upper fuel main assembly is a high-temperature alloy round tube with a thickness of approximately 1mm and a diameter of φd (approximately 22mm). It is machined into a semi-circular main tube with a diameter of φD1 (approximately 886mm), and 10-φB (d1 approximately φ4.5mm) holes are drilled on the round tube at specific angles. A schematic diagram is shown below. Figure 1 As shown in Figure 2, the structural diagrams of the remaining assembly components are as follows. The fuel pipe is a high-temperature alloy round pipe with a thickness of about 1 mm and a diameter of d2 (about φ6.5 mm) that is formed and then processed with the nozzle. It is a thin-walled and easily deformable pipe. The main fuel pipe and each branch pipe are processed with an irregular spatial layout, and the positional accuracy of each branch pipe and the main pipe must be controlled within ±0.05 mm. Otherwise, it will lead to uneven fuel distribution, pipeline vibration and leakage and other faults.

[0004] Current processing technologies generally employ a split-type clamping method, which involves first fixing the main pipe with a simple clamp, then manually marking and positioning it, followed by step-by-step welding. This processing method has the following problems: 1. The pipes are irregularly shaped and spatially distributed. Manual adjustment relies on human experience, resulting in low positioning efficiency. Clamping a single component takes more than 180 minutes, and accuracy is difficult to guarantee, with deviations often ≥ ±0.15mm. At the same time, manual marking relies on the experience of the operators, making it difficult to ensure the consistency of the irregular spatial positions of multiple pipes. During mass production, the accuracy fluctuates greatly, and the pass rate is less than 85%. 2. Thermal deformation during welding causes deviations in the position of the pipes, requiring secondary adjustments after welding, which is a cumbersome process; the positioning and welding processes are separated, and positional shifts are prone to occur during workpiece transfer, which, combined with welding thermal deformation, leads to a high risk of exceeding accuracy tolerances. 3. The welding of the branch pipe and the subsequent external nut are not consistent with the machining reference, which can easily cause reference deviation and result in insufficient machining accuracy of the branch pipe port; the lack of dedicated positioning and limit constraints makes the branch pipe prone to radial or circumferential displacement during welding, resulting in uneven port gaps, affecting weld strength and sealing performance, and thus affecting the product quality of the entire fuel main pipe assembly.

[0005] In existing technologies, relevant patents have also attempted to address some problems in the assembly of fuel manifolds. For example, Chinese invention patent CN117399874A discloses an assembly device and method for an aero-engine fuel manifold. This method uses multiple positioning structures to position the fuel manifold in a tubular groove and position the inlet at a predetermined location. Simultaneously, a centering structure and positioning blocks are used to position and support the inlet pipe, solving the problem of misalignment between the inlet pipe and the inlet hole contact surface, thus improving assembly accuracy and safety. However, this solution mainly addresses two-dimensional or simple three-dimensional positioning of the fuel manifold and inlet pipe. For multi-pipe structures with irregular spatial distribution, it lacks an effective overall spatial position locking mechanism and does not address thermal deformation control during welding, making it difficult to meet the requirement of ±0.05mm accuracy for the pipe positions. Chinese invention patent CN114876646B discloses a support structure and fuel manifold assembly for a gas turbine fuel manifold. A rotatable connecting rod and pipe clamp allow the fuel manifold to rotate circumferentially to counteract thermal expansion stress and reduce the requirements for welding and manufacturing precision. However, this solution focuses on the support and thermal compensation of the fuel main pipe, and does not solve the problem of precise positioning of the branch pipes and the main pipe before welding. In particular, for the assembly of thin-walled and easily deformable pipes in irregular spaces, it still relies on traditional clamping methods, which cannot avoid the errors of manual marking and positioning and the effects of welding thermal deformation.

[0006] Therefore, there is an urgent need for an integrated technical solution that can accurately locate the irregular spatial positions of the main pipe and branch pipes, and integrate assembly and welding, in order to solve the pain points of efficiency and accuracy in the processing of fuel pipeline components under spatial conditions. Summary of the Invention

[0007] The purpose of this invention is to provide a welding positioning and limiting device and integrated processing method for a fuel main pipe assembly based on irregular spatial position in an aero-engine, which aims to solve the problems of low clamping and positioning efficiency, poor accuracy, and easy deviation of the processing reference after welding when the fuel main pipe and multiple branch pipes are irregularly spatially distributed.

[0008] The technical solution of the present invention: 1. A pipe welding positioning device based on irregular spatial position, including a base plate, and a lower limiting structure, a middle limiting structure and an upper limiting structure disposed on the base plate; The lower limiting structure includes an annular second positioning seat, the upper end of which is provided with a profile groove for positioning the pipe fitting; The central limiting structure includes multiple first guide posts arranged along a semicircle. The upper end of each first guide post is supported by a limiting seat, and the side of the limiting seat is provided with a profile groove for positioning the pipe fitting. The upper limiting structure includes an external clamping mechanism and a side fixing mechanism. The external clamping mechanism consists of multiple "7"-shaped clamping units arranged in a semi-circular pattern. Each clamping unit includes a hinge seat, a hinge plate, and a pressure plate. The upper fixing mechanism includes a limiting seat and multiple first positioning seats evenly arranged on the upper end of the limiting seat. The first positioning seats have a profile groove for positioning the pipe fitting.

[0009] Furthermore, the second positioning seat is a semi-circular block with a profiled groove on its top. The profiled groove has multiple through grooves extending radially around its circumference.

[0010] Furthermore, the base plate is a semi-circular plate structure, with a first support and a second support respectively provided at both ends of its straight edge. The front of both the first support and the second support is provided with a positioning pin and a pressing hook, and the pressing hook is integrally formed by an ear plate and a cylindrical pin.

[0011] Furthermore, the hinge seat is positioned on the base plate by hexagonal screws and cylindrical pins, and a right-angled hinge plate is hinged to its upper end. A pressure plate is installed on the other side of the hinge plate by bolts, and a limit pin is provided on the other side. A limit plate is also fixed to the connection section between the hinge plate and the base plate, and the limit plate is locked by rectangular head screws.

[0012] Furthermore, the guide block is constructed as a semi-circular block, which is axially stacked and fixed to the upper end of the limiting seat. A first positioning seat in the shape of a "Z" is arranged on the upper end face of the guide block, and several limiting pins are provided to pass through the guide block from top to bottom and press against the limiting seat below, thereby forming a radial limiting constraint on the guide block.

[0013] Furthermore, the second positioning seat, the first positioning seat, and the limiting seat are made of 45# steel with heat treatment, and their hardness reaches HRC28-32. The first, second, and third profile grooves provided on them have a positional accuracy controlled within ±0.02mm in the X, Y, and Z axes of the spatial coordinate system. In addition, the inner wall surface of each profile groove is coated with a wear-resistant coating.

[0014] An integrated processing method is used to process a pipe fitting consisting of a semi-circular fuel main pipe, several irregularly shaped fuel branch pipes assembled thereon via tees, and tapered connectors at both ends of the fuel main pipe; the method includes the following steps: Step 1: Assemble the welding positioning device; Step 2: Clamp and position the fuel main pipe. Place the fuel main pipe equipped with the tee into the groove of the second positioning seat of the clamp, ensuring that the gap between the outer wall of the fuel main pipe and the groove is no more than 0.02mm. Use the positioning pins and pressure hooks on the first and second supports to limit and fix the tapered connectors at both ends. Check and confirm that the coaxiality between the axis of the fuel main pipe and the axis of the groove is no more than 0.02mm, and complete the reference positioning of the main pipe. Step 3: Clamping and positioning the fuel manifolds. Place each fuel manifold assembly into the second groove of the first positioning seat and the third groove of the limiting seat in sequence, ensuring that the end of the fuel manifold without the nozzle is tightly fitted with the tee. Rotate the hinge plate inward to press the nozzle firmly against the pressure plate and the limiting pin, and install the rectangular head screw to lock it in place. Use a 0.02mm feeler gauge to check the fit gap between the fuel manifold and each groove. The fit is considered acceptable if the feeler gauge cannot be inserted. This completes the locking and positioning of the irregular spatial posture of all fuel manifolds. Step 4: After completing the precise positioning in Steps 2 and 3, perform integrated machining of the fuel main and fuel branch lines.

[0015] Furthermore, the clamping and positioning of the fuel main pipe in step 2 is carried out in the following order: first, several tees are pre-assembled onto the fuel main pipe; then, the fuel main pipe with tees is placed in the profile groove of the second positioning seat; finally, the tapered connectors at both ends of the fuel main pipe are limited and fixed by the positioning pins and pressure hooks on the first and second supports.

[0016] Furthermore, the assembly of the positioning and limiting device in step 1 is performed according to the following steps: Step 11: Basic positioning. First, fix the second positioning seat on the base plate according to the hole positions in the design drawings to establish the initial benchmark. Step 12: Install and fix the hinge seat, hinge plate, pressure plate, limit plate, rectangular head screw, limit pin, first bushing and related standard parts in the designated positions on the base plate according to the hole positions in the design drawings. Step 13: Installation of the guide and limiting mechanism: Install and fix the first guide post, the limiting seat, the limiting pin, the guide block, the first positioning seat, the second guide post and related fasteners on the base plate in sequence according to the hole positions in the design drawings. Step 14: Install and fix the positioning pin, first support, second support, pressure hook, second bushing and related standard parts on the base plate according to the hole positions in the design drawings to complete the assembly of the entire positioning and limiting device.

[0017] Furthermore, step 4 specifically involves: Step 41: Welding of the upper fuel manifold assembly. For the upper fuel manifold assembly, the fuel manifold is brazed to the tee and the tapered connector, and the brazing filler metal is HBNi82CrSiB. The fuel manifold is connected to each fuel branch pipe by argon arc welding. Both the brazing and argon arc welding adopt the "symmetrical welding method" to control deformation and complete the welding process of the upper fuel manifold assembly.

[0018] Step 42: Welding of the lower fuel manifold assembly. The same processing method and positioning and limiting fixture with the same structure as in Step 41 are used to complete the welding of the lower fuel manifold assembly.

[0019] Step 43: Assembly. Connect and tighten the machined upper fuel manifold assembly and lower fuel manifold assembly using their respective tapered connectors and external nuts to complete the final assembly of the entire fuel manifold assembly. The beneficial effects of this invention are: 1. High positioning accuracy: Through a three-level collaborative positioning system consisting of the second positioning seat main pipe groove reference, the positioning seat and limit seat attitude positioning, and the docking positioning of the port pressure hook and limit pin, the spatial position error of the fuel main pipe-branch pipe irregular shape is controlled within ±0.02mm, and the batch production qualification rate is increased to 98%, which is far higher than the traditional process of 85%. 2. Superior processing efficiency: The integrated processing method consolidates assembly and positioning within the welding process, eliminating the need for multiple workpiece transfers. The processing time for a single main pipe-branch pipe assembly is reduced from the traditional 180 minutes to 95 minutes, increasing production efficiency by 47.3%. 3. It is easy to operate. The pipe clamping mechanism adopts a quick-release design, and the port block can be quickly installed through the positioning guide structure, which simplifies the operation process. Ordinary operators can get started after simple training, reducing the reliance on professional skills.

[0020] 4. By using a special device to check the fit between the various surfaces and parts, the spatial position of each component in the fuel main assembly can be quickly inspected. Specifically, a 0.02mm feeler gauge can be used to check the fit gap between the branch pipe and each groove (no insertion is acceptable). This invention achieves rapid clamping and precise calibration of the branch pipe spatial position by designing an integrated fixture with irregularly shaped spatial positioning grooves. It simultaneously completes the welding of the main pipe and branch pipes and the integrated processing after welding, ensuring the spatial position accuracy and structural integrity of the fuel main pipe assembly. This invention improves clamping efficiency by more than 47.3% and the positioning accuracy can reach ±0.02mm. It is suitable for the mass production of irregularly shaped fuel main pipe assemblies in aerospace, engine and other fields. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure on the fuel main; Figure 2-1 This is a schematic diagram of a conical nozzle structure; Figure 2-2 This is a schematic diagram of a T-junction; Figure 2-3 This is a schematic diagram of the fuel line structure; Figure 3-1 This is a front view of the positioning and limiting device structure of the upper fuel manifold assembly; Figure 3-2 This is a top view of the positioning and limiting device structure of the upper fuel manifold assembly; Figure 4-1 This is a front view of the second positioning seat structure; Figure 4-2 This is a top view of the second positioning seat structure; Figure 5 This is a schematic diagram of the pressure hook structure; Figure 6-1 This is a schematic diagram of the first positioning seat structure. Figure 1 ; Figure 6-2 This is the second schematic diagram of the first positioning seat structure; Figure 7-1 This is a schematic diagram of the limiting seat structure. Figure 1 ; Figure 7-2 This is schematic diagram two of the limiting seat structure; Figure 8-1 This is a schematic diagram of the pressure plate structure. Figure 1 ; Figure 8-2 This is schematic diagram two of the pressure plate structure; Figure 9 This is a schematic diagram of the positioning and limiting device for the lower fuel manifold assembly; Reference numerals in the attached drawings: base plate-1, hinge seat-2, hinge plate-3, pressure plate-4, positioning pin-5, first support-6, first guide post-7, limit seat-8, limit pin-9, guide block-10, first positioning seat-11, second support-12, limit plate-13, pressure hook-14, rectangular head screw-15, limit pin-16, second positioning seat-17, first bushing-18, second bushing-19, second guide post-20. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should not be construed that the scope of the subject matter of the present invention is limited to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0024] A precision positioning and limiting device enables the precise distribution of the irregular spatial positions of the fuel main pipe and its various branch pipes, tees, tapered connectors, etc., in a fuel main pipe assembly. The device includes a base plate 1, a hinge seat 2, a hinge plate 3, a pressure plate 4, a positioning pin 5, a first support 6, a first guide post 7, a limiting seat 8, a limiting pin 9, a guide block 10, a first positioning seat 11, a second support 12, a limiting plate 13, a pressure hook 14, a rectangular head screw 15, a limiting pin 16, a second positioning seat 17, a first bushing 18, a second bushing 19, a second guide post 20, an internal hexagonal screw, a cylindrical pin, and a bolt. The structure of the flat-head screw and other machined parts is shown in Figure 3. The machining method can be simply described as follows: 10 tees are respectively assembled at the d1 hole position of the upper fuel main pipe, and then placed in the second positioning seat 17 profile 1. The conical nozzle is then fixed by the positioning pin 5 and the pressure hook 14 on the support. Finally, the spatial position of each fuel branch pipe is fixed by the pressure plate 4 of the hinge seat 2, the limiting pin 16 and other devices. After the device is fixed, the conical nozzle, tee and each fuel branch pipe are machined by brazing and argon arc welding respectively. The device is used for limiting and cooling to reduce welding deformation.

[0025] The operation steps can be carried out from two aspects: the design and assembly of the positioning and limiting device, and the positioning, limiting, clamping, and processing methods of the parts. 1. Positioning and Limiting Device Design: Positioning seat 2 is made of 45# steel with heat treatment (hardness HRC28-30), and has a semi-circular φd-shaped groove 1 that matches the upper fuel main pipe. Positioning seat 1 is made of 45# steel with heat treatment (hardness HRC28-30), and has a semi-circular φd2-shaped groove 2 that matches the fuel branch pipes. The limiting seat is made of 45# steel with heat treatment (hardness HRC28-30), and has a groove 3 that matches the fuel branch pipes. This ensures stable positioning of the fuel main pipe and each branch pipe. The spatial coordinates (X / Y / Z axis coordinates, angle around the axis) of each groove are pre-fabricated by a five-axis machining center to ensure that the spatial position accuracy reaches ±0.02mm. In addition, WC-Co wear-resistant coating is sprayed on the inner wall of each groove to extend the service life and ensure that the positioning accuracy does not decrease significantly after thousands of clamping cycles.

[0026] 2. Implementation steps for assembling the positioning and limiting device: Step 1: Fabricate each component according to the design drawings to conform to the design drawings; Step 2: Assemble the second positioning seat 17 onto the base plate according to the mounting hole positions shown in the device structure diagram; Step 3: Assemble 10 sets each of hinge seat 2, hinge plate 3, pressure plate 4, limit plate 13, rectangular head screw 15, limit pin 16, first bushing 18, cylindrical pin, bolt, and flat head screw on the base plate 1 according to the mounting hole positions shown in the device structure diagram. Step 4: Assemble the first guide post 7, the limiting seat 8, the limiting pin 9, the guide block 10, the first positioning seat 11, the second guide post 20, and the internal hex screws on the base plate 1 according to the mounting hole positions shown in the assembly diagram. Step 5: Assemble the positioning pin 5, first support 6, second support 12, pressure hook 14, second bushing 19, nut, and flat-head screw on the base plate according to the mounting hole positions shown in the device structure diagram. 3. Part positioning and clamping implementation steps Step 1: Remove the rectangular head screw 15, causing the hinge plate 3, pressure plate 4, limit pin 16, and other components on the hinge seat 2 to rotate outwards. Step 2: Install 10 tees onto the d1 hole of the upper fuel main pipe, ensuring that the coaxiality between the d1 hole and the corresponding hole of the tee is ≤0.02mm, and ensure the assembly position. Step 3: Place the upper fuel main pipe with the tee into the groove 1 of the second positioning seat 17 of the fixture, so that the outer wall of the round pipe of the upper fuel main pipe is in close contact with the groove 1, ensuring that the gap is ≤0.02mm; the two ends are limited and fixed by the positioning pins 5 and the pressure hooks 14 on the support and the conical connector is assembled with the upper fuel main pipe. Check that the coaxiality between the main pipe axis and the groove axis is ≤0.02mm. After passing the test, the main pipe reference positioning is completed.

[0027] Step 4: Place each of the 10 fuel manifold assemblies into the groove 2 of the first positioning seat 11 and the groove 3 of the limiting seat 8, ensuring that the end of the fuel manifold assembly without the nozzle is tightly fitted with the tee. Rotate the hinge plate 3, pressure plate 4, and limiting pin 16 inwards, and install the rectangular head screw 15. Adjust the position of the pressure plate 4 and limiting pin 16 to fix the nozzle. At the same time, use a 0.02mm feeler gauge to check the fit gap between the manifold and each groove (no excess is acceptable). This completes the spatial positioning and locking of each manifold. 4. Integrated machining method for upper fuel manifold assembly Step 1: The welding method between the upper fuel manifold and the tee and tapered connector in the upper fuel manifold assembly is brazing, and the brazing filler metal is HBNi82CrSiB; the welding method between the upper fuel manifold and each fuel branch pipe is argon arc welding; both brazing and argon arc welding adopt the "symmetrical welding method" to complete the processing of the upper fuel manifold assembly. Step 2: The lower fuel manifold assembly is processed using the same processing method as the upper fuel manifold assembly and a positioning and limiting fixture with the same structure. Step 3: Connect the upper fuel manifold assembly and the lower fuel manifold assembly using tapered connectors and external nuts to complete the processing of the fuel manifold assembly; Example 1 discloses the design of a positioning and limiting device, such as... Figure 3-1 and 3-2 As shown, the second positioning seat 17 is as follows Figure 4-1 and 4-2 The steel shown is made of 45# steel with heat treatment (hardness HRC28-30). It has a semi-circular φd-shaped groove adapted to the upper fuel main pipe, and a first positioning seat 11. Figure 6-1 and 6-2 As shown, it is made of 45# steel with heat treatment (hardness HRC28-30), and has two semi-circular φd2-shaped grooves on it to match the fuel distribution pipe, as well as a limiting seat, such as... Figure 7-1 and 7-2 As shown, 45# steel is used for heat treatment (hardness HRC28-30). It is equipped with three profiled grooves that are compatible with the fuel manifolds to ensure stable positioning of the fuel main pipe and each branch pipe. The spatial coordinates (X / Y / Z axis coordinates, angle around the axis) of each profiled groove are pre-fabricated by a five-axis machining center to ensure that the spatial position accuracy reaches ±0.02mm. In addition, WC-Co wear-resistant coating is sprayed on the inner wall of each profiled groove to extend the service life and ensure that the positioning accuracy does not decrease significantly after thousands of clamping cycles.

[0028] Example 2: Implementation steps of the positioning and limiting device assembly: Step 1: Fabricate each component according to the design drawings to conform to the design drawings; Step 2: Assemble the second positioning seat 17 on the base plate 1 according to the mounting hole positions shown in the device structure diagram; Step 3: Assemble 10 sets each of hinge seat 2, hinge plate 3, pressure plate 4, limit plate 13, rectangular head screw 15, limit pin 16, first bushing 18, cylindrical pin, bolt, and 24 flat head screw on the base plate according to the mounting hole positions shown in the device structure diagram. Step 4: Assemble the first guide post 7, the limit seat 8, the limit pin 9, the guide block 10, the first positioning seat 11, the second guide post 20, and the internal hex screws on the base plate according to the mounting hole positions shown in the assembly diagram. Step 5: Assemble the positioning pin 5, first support 6, second support 12, pressure hook 14, second bushing 19, nut 25, and flat-head screw 26 on the base plate according to the mounting hole positions shown in the device structure diagram. Part positioning and clamping implementation steps Step 1: Remove the rectangular head screw 15 to allow the hinge plate 3, pressure plate 4, limit pin 16 and other components on the hinge seat 2 to rotate outward. Step 2: Install 10 tees onto the d1 hole position on the fuel main pipe, ensuring that the coaxiality between the d1 hole and the corresponding hole of the tee is ≤0.02mm, and ensure the assembly position. Step 3: Place the fuel main pipe with the tee assembly into the groove 1 of the second positioning seat 17 of the clamp, ensuring that the outer wall of the round pipe on the fuel main pipe is tightly against the groove 1, guaranteeing a gap ≤0.02; both ends are secured by positioning pins 5 and pressure hooks 14 on the first support 6 and the second support 12, as shown. Figure 5 As shown, the conical nozzle is positioned and fixed to the fuel main pipe. The coaxiality between the main pipe axis and the groove axis is checked to be ≤0.02mm. After passing the test, the main pipe reference positioning is completed. Step 4: Place the 10 fuel manifold assemblies one by one into the groove 2 of the first positioning seat 11 and the groove 3 of the limiting seat 8, ensuring that the end of the fuel manifold assembly without the nozzle is tightly fitted with the tee assembly. Rotate the hinge plate 3 and the pressure plate 4 inward. Figure 8-1 and 8-2 As shown, the limit pin 16 and other components are installed with rectangular head screws 15. The nozzle is fixed by adjusting the position of the pressure plate 4 and the limit pin 16. At the same time, a 0.02mm feeler gauge is used to check the fitting gap between the branch pipe and each type of groove (no insertion is acceptable) to complete the locking and positioning of the irregular spatial posture of each branch pipe.

[0029] Integrated machining method for upper fuel manifold assembly Step 1: The welding method between the fuel main pipe and the tee and tapered connector in the upper fuel main pipe assembly is brazing, with HBNi82CrSiB as the filler metal; the welding method between the upper fuel main pipe and each fuel branch pipe is argon arc welding, with four evenly spot-welded points (90° apart) around each branch pipe end, and each component is welded according to the corresponding welding parameters for high-temperature alloys; both brazing and argon arc welding adopt the "symmetrical welding method", first welding the tapered connectors and tee on both sides of the main pipe, then welding the middle tee, and finally processing and welding each branch pipe at both ends and the middle branch pipe in the same way, to further offset thermal deformation, ensure uniform weld formation and controllable thermal deformation; at the same time, during the welding heating process, each welded part is in a limited state, completing the processing of the upper fuel main pipe assembly; Step 2: Use the same machining method and fixture as the upper fuel manifold assembly. Figure 9 Complete the machining of the lower fuel manifold assembly; Step 3: Connect the upper fuel manifold assembly and the lower fuel manifold assembly using tapered connectors and external nuts to complete the processing of the fuel manifold assembly.

[0030] The foregoing has provided a detailed description of the pipe fitting welding positioning device and integrated processing method based on irregular spatial positions provided by the present invention. Specific examples have been used to illustrate the structure and working principle of the invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A pipe fitting welding positioning device based on irregular spatial position, characterized in that: It includes a base plate (1), and a lower limiting structure, a middle limiting structure and an upper limiting structure disposed on the base plate (1); The lower limiting structure includes an annular second positioning seat (17), the upper end of which is provided with a profile groove for positioning the pipe fitting; The central limiting structure includes multiple first guide posts (7) arranged along a semicircle. The upper end of each first guide post (7) is supported by a limiting seat (8). The side of the limiting seat (8) is provided with a profile groove for positioning the pipe fitting. The upper limiting structure includes an external clamping mechanism and a side fixing mechanism. The external clamping mechanism consists of multiple "7"-shaped clamping units arranged in a semi-circular pattern. Each clamping unit includes a hinge seat (2), a hinge plate (3), and a pressure plate (4). The upper fixing mechanism includes a limiting seat (8) and multiple first positioning seats (11) evenly arranged on the upper end of the limiting seat (8). The first positioning seat (11) has a profile groove for positioning the pipe fitting.

2. The pipe fitting welding positioning device based on irregular spatial position according to claim 1, characterized in that: The second positioning seat (17) is a semi-circular block with a profile groove on its top. Multiple through grooves extending radially are evenly distributed around the profile groove.

3. The pipe fitting welding positioning device based on irregular spatial position according to claim 1, characterized in that: The base plate (1) is a semi-circular plate structure, with a first support (6) and a second support (12) respectively at the two ends of its straight edge. The front of the first support (6) and the second support (12) are provided with a positioning pin (5) and a pressure hook (14). The pressure hook (14) is integrally formed by an ear plate and a cylindrical pin.

4. The pipe fitting welding positioning device based on irregular spatial position according to claim 1, characterized in that: The hinge seat (2) is positioned on the base plate (1) by means of hexagonal screws and cylindrical pins. A right-angle bent hinge plate (3) is hinged to its upper end. A pressure plate (4) is installed on the other side of the hinge plate (3) by means of bolts. A limit pin (16) is provided on the other side. A limit plate (13) is also fixed to the connection section between the hinge plate (3) and the base plate (1). The limit plate (13) is locked by means of rectangular head screws (15).

5. The pipe fitting welding positioning device based on irregular spatial position according to claim 1, characterized in that: The guide block (10) is a semi-circular block with its axial stack fixed to the upper end of the limiting seat (8). A first positioning seat (11) in the shape of a "Z" is arranged on the upper end face of the guide block (10), and several limiting pins (9) are provided to pass through the guide block (10) from top to bottom and press against the limiting seat (8) below, thereby forming a radial limiting constraint on the guide block (10).

6. The pipe fitting welding positioning device based on irregular spatial position according to claim 1, characterized in that: The second positioning seat (17), the first positioning seat (11) and the limiting seat (8) are made of 45# steel and heat treated to achieve a hardness of HRC28-32. The first, second and third profile grooves are provided on them and their positional accuracy in the X, Y and Z axes of the spatial coordinate system is controlled within ±0.02mm. Furthermore, the inner wall surface of each profile groove is coated with a wear-resistant coating.

7. An integrated processing method, characterized in that, A pipe fitting is used to process a semi-circular fuel main pipe, several irregularly shaped fuel branch pipes assembled thereon via tees, and tapered connectors located at both ends of the fuel main pipe; the method includes the following steps: Step 1: Assemble the welding positioning device; Step 2: Clamp and position the fuel main pipe. Place the fuel main pipe equipped with the tee into the groove of the second positioning seat (17) of the clamp, ensuring that the gap between the outer wall of the fuel main pipe and the groove is no more than 0.02mm. Use the positioning pins (5) and the pressure hooks (14) on the first support (6) and the second support (12) to limit and fix the conical nozzles at both ends. Check and confirm that the coaxiality between the axis of the fuel main pipe and the axis of the groove is no more than 0.02mm, and complete the reference positioning of the main pipe. Step 3: Clamping and positioning the fuel manifolds. Place each fuel manifold assembly into the second groove of the first positioning seat (11) and the third groove of the limiting seat (8) in sequence, ensuring that the end of the fuel manifold without the nozzle is tightly fitted with the tee. Rotate the hinge plate (3) inward so that the pressure plate (4) on it and the limiting pin (16) press and fix the nozzle, and install the rectangular head screw (15) to lock it. Use a 0.02mm feeler gauge to check the fit gap between the fuel manifold and each groove. It is considered qualified if the feeler gauge cannot be inserted. Complete the locking and positioning of the irregular spatial posture of all fuel manifolds. Step 4: After completing the precise positioning in Steps 2 and 3, perform integrated machining of the fuel main and fuel branch lines.

8. The integrated processing method according to claim 7, characterized in that: In step 2, the clamping and positioning of the fuel main pipe are carried out in the following order: First, several tees are pre-assembled onto the fuel main pipe; then, the fuel main pipe with tees is placed in the groove of the second positioning seat (17); finally, the conical connectors at both ends of the fuel main pipe are limited and fixed by the positioning pins (5) and the pressure hooks (14) on the first support (6) and the second support (12).

9. The integrated processing method according to claim 1, characterized in that: The assembly of the positioning and limiting device in step 1 shall be performed according to the following steps: Step 11: Basic positioning. The second positioning seat (17) is first fixedly installed on the base plate (1) according to the hole positions in the design drawings to establish the initial benchmark. Step 12: Install and fix the hinge seat (2), hinge plate (3), pressure plate (4), limit plate (13), rectangular head screw (15), limit pin (16), first bushing (18) and related standard parts in the designated positions of the base plate (1) according to the hole position relationship of the design drawings. Step 13: Installation of the guide limiting mechanism: Install and fix the first guide post (7), the limiting seat (8), the limiting pin (9), the guide block (10), the first positioning seat (11), the second guide post (20) and related fasteners on the base plate (1) in sequence according to the hole positions in the design drawings. Step 14: Install and fix the positioning pin (5), the first support (6), the second support (12), the pressure hook (14), the second bushing (19) and related standard parts on the base plate (1) according to the hole positions in the design drawings, and complete the assembly of the entire positioning and limiting device.

10. The integrated processing method according to claim 1, characterized in that: Specifically, step 4 is as follows: Step 41: Welding of the upper fuel manifold assembly. For the upper fuel manifold assembly, the fuel manifold is brazed to the tee and the tapered connector. The brazing filler metal is HBNi82CrSiB. The fuel main pipe is connected to each fuel branch pipe by argon arc welding; both brazing and argon arc welding adopt the "symmetrical welding method" to control deformation and complete the welding process of the upper fuel main pipe assembly. Step 42: Welding of the lower fuel manifold assembly. The same processing method and positioning and limiting fixture with the same structure as in Step 41 are used to complete the welding of the lower fuel manifold assembly. Step 43: Assembly. Connect and tighten the finished upper fuel manifold assembly and lower fuel manifold assembly using their respective tapered connectors and external nuts to complete the final assembly of the entire fuel manifold assembly.

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