Welding method and tool for fixing the upper liner plate and the main pipe of a fluid distribution / collecting pipe assembly

Abstract

The application provides a welding fixing method and tooling of a lining plate and a main pipe of a fluid distribution / collecting pipe assembly, the main pipe wall of the fluid distribution / collecting pipe assembly is provided with at least three branch pipe holes with a diameter less than 0.65 times of the diameter of the main pipe, the lining plate is arc-shaped and has lining plate holes, and the welding fixing of the lining plate and the main pipe comprises the following steps: placing the lining plate to be fixed into a containing groove on a core rod; sleeving the main pipe outside the core rod after placing the lining plate, so that the arc surface of the lining plate is attached to the inner wall of the main pipe and each lining plate hole is substantially opposite to the corresponding branch pipe hole; each positioning pin is sequentially penetrated into the corresponding branch pipe hole and the lining plate hole from the outside of the main pipe and is inserted into a positioning pin avoiding recess on the core rod, so as to coaxially position the branch pipe hole and the corresponding lining plate hole; after coaxial positioning, a pressing assembly is used to press the lining plate to be attached to the inner wall of the main pipe; and a self-fusion type welding is used to connect the lining plate and the inner wall of the main pipe.

Description

Technical Field

[0001] This invention relates to the field of refrigeration components, and particularly to a welding and fixing method and tooling for the upper liner and main pipe of a fluid distribution / manifold assembly. Background Technology

[0002] Fluid manifold assemblies are common components in refrigeration systems, used in evaporators or condensers in refrigerant systems, and in fan coil units or combined air conditioning units in water systems. To address the problems of easy deformation and high cost associated with traditional copper-processed fluid manifold assemblies, the inventors proposed a novel water manifold in Chinese patent CN218494411U. This novel manifold uses a high-strength, thin-walled stainless steel pipe as the main pipe, with multiple branch pipes welded to the pipe wall. Due to the thin wall of the main pipe, to ensure sufficient weld strength for the branch pipes, the patent also proposes installing a liner plate on the inner wall of the stainless steel main pipe. The liner plate has multiple liner plate holes corresponding to the multiple branch pipe holes. Each branch pipe is inserted into the corresponding branch pipe hole, with the inserted end extending to the corresponding liner plate hole. The depth of the branch pipe hole and the depth of the liner plate hole together provide the welding depth for the branch pipe to meet the welding strength requirements.

[0003] The assembly of the branch pipe requires a high degree of coaxiality between the branch pipe hole and the corresponding liner hole. This requirement makes the assembly of the liner and the main pipe a challenging aspect of the product's manufacturing process. To address this issue, the inventors proposed using a mandrel with a pin to weld and fix the liner and the main pipe together. Figure 1 As shown, in this scheme, the pin 10A and the mandrel 10B are a fixed assembly structure. The pin 10A, following the mandrel 10B, extends into the main pipe 10C and passes through the liner hole on the inner liner plate 10D, the branch pipe hole, and the liner hole on the outer liner plate 10D' from the inside out to achieve coaxial positioning of the branch pipe hole and the inner and outer liner hole. In the fixed assembly structure of the pin and mandrel, the spacing between adjacent pins is fixed, and the spacing between adjacent branch pipe holes on the main pipe is also fixed. Due to the influence of dimensional tolerances and geometric tolerances during machining, the pin spacing accuracy and the branch pipe hole spacing accuracy cannot be completely consistent; for example... Figure 1A As shown, although the nominal dimensions for the branch pipe hole spacing L1 and the center distance L of the pin on the mandrel are both 15mm, both the branch pipe hole spacing L1 and the pin distance L fluctuate due to the allowable dimensional tolerance (±0.1mm) during manufacturing. This fluctuation accumulates as the number of branch pipe holes increases; for example... Figure 1A (a) The total spacing of the seven branch pipe holes, L1_total, is 15.03 + 15.0 + 15.03 + 14.99 + 15.02 + 15.03 + 15.02 = 105.12 mm; while Figure 1A(b) The total distance L between the seven pins is L_total = 15 + 14.98 + 14.98 + 14.99 + 15.0 + 15.01 + 15 = 104.96 mm. The more branch pipe holes there are, the more significant the cumulative error between the center distance of the branch pipe holes and the center distance of the pins will be, making it difficult for the pins to pass through the branch pipe holes, thus causing difficulties in assembling the liner and main pipe. Furthermore, the form and position tolerances of the pins themselves will further worsen the assembly of the pins with the main pipe and liner. In addition, in this positioning method, the pins need to pass through the branch pipe holes and liner holes from inside the main pipe outwards, making alignment and assembly difficult and inefficient. Furthermore, the height of the pins also requires a large diameter difference between the mandrel and the main pipe to achieve mandrel insertion; for small-diameter main pipes (such as those with a diameter less than 15.88 mm), the radial clearance space for the pins is insufficient, making it difficult for the pins to pass through the liner holes and branch pipe holes. In other words, mandrels with pins are suitable for fluid manifold assemblies with a large main pipe diameter and a small number of branch pipes (with a small cumulative tolerance between the pin spacing and the branch pipe hole spacing), but they are difficult to apply to fluid manifold assemblies with a small main pipe diameter or a large number of branch pipes.

[0004] Similar to the positioning method using a mandrel with a pin provided by the inventor, Chinese patent CN204603644U provides a separate welding fixture structure for a four-way valve body component. This welding fixture is used to assemble multiple connecting pipes and the valve body of a four-way valve. In this structure, the positioning rods for the E and C connecting pipes and the S connecting pipe are fixed to the upper guide plate of the positioning rod assembly, thus fixing the spacing between the positioning rods. The spacing between the three connecting pipe holes on the valve body that receive the E, S, and C connecting pipes is also fixed. Due to dimensional and geometric tolerances, the spacing between the positioning rods and the connecting pipe holes cannot be perfectly aligned, making it difficult for the positioning rods to position the corresponding connecting pipes, or even preventing positioning due to interference. Similarly, the S connecting pipe positioning pins and D connecting pipe positioning pins fixed to the lower horizontal plate are also difficult to position coaxially with the S connecting pipe holes and D connecting pipe holes on the valve body. Furthermore, although Chinese patent CN204603644U mentions using the weight of the positioning rod assembly itself to press the workpiece, this pressing method only presses the three connecting pipes E, S, and C against the valve seat inside the valve body. The valve body and valve seat are in a loose fit, resulting in a large assembly gap. During brazing, the molten solder flows along this large assembly gap, making it difficult to fill the gap, leading to welding quality problems such as broken welds and incomplete welds between the valve seat and valve body after welding. In addition, this patent also suffers from the problem that inconsistent spacing between the connecting pipes and their corresponding positioning rods makes it difficult to achieve consistent pressing of the three connecting pipes. Clearly, for products like fluid manifold assemblies with numerous branch pipes and liners, the tooling and fixtures provided by Chinese patent CN204603644U will be even more difficult to apply. Therefore, the coaxial assembly of the liners and main pipes, as well as the pressing and fitting of the liners and main pipes, have become urgent technical problems that need to be solved for fluid manifold assemblies. Summary of the Invention

[0005] In order to overcome at least one deficiency of the prior art, the present invention provides a welding and fixing method and tooling for the upper liner and main pipe of a fluid distribution / manifold assembly.

[0006] To achieve the above objectives, the present invention provides a method for welding and fixing a liner and a main pipe of a fluid manifold assembly. The fluid manifold assembly includes a main pipe and a liner. The main pipe has at least three branch pipe holes on its wall for welding branch pipes, and the diameter of the branch pipe holes is less than 0.65 times the diameter of the main pipe. The liner is arc-shaped and has liner holes. The welding and fixing of the liner and the main pipe includes the following steps:

[0007] Place the liner to be fixed into the receiving groove on the mandrel. The receiving groove has positioning pin clearance recesses corresponding to multiple branch pipe holes.

[0008] Insert the main pipe onto the outside of the mandrel after the liner is placed, so that the arc surface of the liner fits against the inner wall of the main pipe and each liner hole is approximately opposite to the corresponding branch pipe hole.

[0009] Each positioning pin passes through the corresponding branch pipe hole and liner hole from the outside of the main pipe inward and is inserted into the positioning pin avoidance recess on the mandrel to coaxially position the branch pipe hole and the corresponding liner hole.

[0010] For the liner hole and branch pipe hole after the positioning pin is positioned, the clamping assembly is used to press the liner tightly against the inner wall of the main pipe;

[0011] The inner wall of the main pipe is connected by a self-fusion welding method.

[0012] According to an embodiment of the present invention, when a liner plate also needs to be placed on the outer wall of the main pipe, the welding and fixing method further includes:

[0013] After the main tube is inserted into the outside of the mandrel, the arc surface of the liner to be placed is fitted against the outer wall of the main tube, and each liner hole is roughly opposite to the corresponding branch pipe hole.

[0014] When inserting the locating pins, each locating pin will pass through the liner hole, branch pipe hole and inner liner hole on the outer liner in sequence from the outside to the inside and be inserted into the locating pin clearance recess on the mandrel to locate the outer liner, main pipe and inner liner.

[0015] According to one embodiment of the present invention, the positioning pin has a shoulder that abuts against the outer wall of the main pipe or the outer liner plate. The clamping assembly applies force to each positioning pin, and the shoulder on the positioning pin clamps the liner plate and the pipe wall of the main pipe from the outside to the inside after positioning.

[0016] Alternatively, the clamping assembly abuts against the outer wall of the main pipe or the outer liner, clamping the positioned liner and the main pipe wall from the outside in.

[0017] According to one embodiment of the present invention, the positioning pin is pressed in a resilient manner by a pressing component; or, the outer wall of the main pipe or the outer liner is pressed in a resilient manner by a pressing component.

[0018] On the other hand, the present invention also provides a welding and fixing fixture, which uses any of the above-mentioned methods to weld and fix the liner and main pipe on the fluid distribution / manifold assembly. The welding and fixing fixture includes a fixture support, a mandrel, multiple locating pins, and a clamping assembly. The mandrel is disposed on the fixture support, and one end of the mandrel is free during assembly to allow the main pipe to be fitted. The mandrel has a receiving groove for placing the liner, and the receiving groove has locating pin clearance recesses corresponding to multiple branch pipe holes distributed within it. After the main pipe is fitted into the mandrel, each locating pin passes through the corresponding branch pipe hole and liner hole one by one along the outside of the main pipe and is inserted into the locating pin clearance recess on the mandrel to position the liner and main pipe. The clamping assembly is lifted and mounted on the fixture support, and the clamping assembly abuts against the multiple locating pins, the outer wall of the main pipe, or the outer liner to clamp the positioned liner and the main pipe wall.

[0019] According to one embodiment of the present invention, the positioning pin clearance recess on the mandrel is a plurality of clearance holes distributed corresponding to a plurality of branch holes on the main pipe;

[0020] Alternatively, the locating pin clearance recess is one or more clearance grooves that correspond to multiple branch holes on the main pipe and extend along the mandrel axially.

[0021] According to one embodiment of the present invention, the size of the receiving groove on the mandrel matches the size of the liner, and there is a positioning adjustment gap between the side wall of the liner and the side wall of the receiving groove for adjusting the coaxiality of the liner hole.

[0022] According to one embodiment of the present invention, a welding clearance groove is formed in the area covered by the liner plate on the mandrel. The welding clearance groove is located on both sides of the locating pin clearance recess and extends along the axial direction of the mandrel.

[0023] According to one embodiment of the present invention, the tooling bracket includes a base and two brackets located at both ends of the base. The connecting end of the mandrel is rotatably connected to the first bracket and rotates relative to the first bracket with the connection point as the fulcrum. The movable end of the mandrel can be detachably engaged with the second bracket. During assembly, the movable end of the mandrel is detached from the second bracket and is in a free state for the main tube to be inserted.

[0024] According to one embodiment of the present invention, each positioning pin includes an insertion section, a shoulder, and a clamping section connected in sequence. The insertion section passes through the branch pipe hole and the liner hole and is inserted into the positioning pin clearance recess on the mandrel. The cross-sectional diameter of the shoulder is larger than that of the insertion section to abut against the outer wall of the main pipe or the outer liner. The clamping assembly includes a plurality of cylinders disposed on a tooling bracket and a clamping plate connected to the plurality of cylinders. The clamping plate abuts against the clamping section of each positioning pin and clamps each liner against the wall of the main pipe through the shoulder.

[0025] According to one embodiment of the present invention, the clamping assembly further includes an elastic element disposed on the bottom of the clamping plate or on each locating pin clamping section, the elastic element deforming during the clamping stroke of the clamping assembly to compensate for the height difference between the end faces of the clamping plate and the clamping sections of each locating pin.

[0026] According to one embodiment of the present invention, a plurality of positioning areas are formed on the mandrel and distributed along its circumference. Each positioning area includes a receiving groove and a positioning pin avoidance recess formed at the bottom of the receiving groove.

[0027] On the other hand, the present invention also provides a fluid manifold assembly, comprising a main pipe, a liner, and at least three branch pipes. The main pipe has at least three branch pipe holes on its wall, and the diameter of each branch pipe hole is less than 0.65 times the diameter of the main pipe. The liner is arc-shaped and has liner holes, and the liner is assembled to the main pipe by the welding fixing method according to any one of claims 1 to 4. Each branch pipe extends into and is brazed to the corresponding branch pipe hole and liner hole.

[0028] According to an embodiment of the present invention, the liner includes an outer liner disposed on the outer wall of the main pipe. The outer liner is located on the outer periphery of the lowest point of the busbar on the branch pipe hole and is attached to the outer wall of the main pipe. A blocking edge is formed between the outer liner and the outer wall of the main pipe. The blocking edge surrounds the outer periphery of the branch pipe hole in whole or in part to block the solder flow path along the outer wall of the main pipe. The side of the outer liner near the branch pipe hole forms a solder flow port pointing inward into the branch pipe hole.

[0029] Furthermore, on the main pipe section passing through the central axis of the branch pipe hole, a rectangular coordinate system is constructed with the highest point of the main pipe's upper generatrix as the origin, the central axis of the branch pipe hole as the positive direction of the Y-axis, and the radial direction of the main pipe as the X-axis; the ordinate of the initial flow point of the solder at the flow port falls in the positive direction of the Y-axis.

[0030] According to one embodiment of the present invention, the extension direction of the self-fusion weld formed between the outer liner and the outer wall of the main pipe is approximately the same as the side wall edge of the outer liner, and a blocking edge is formed at the self-fusion weld.

[0031] Alternatively, the self-fusion weld and the sidewall edge of the outer liner can together form a blocking edge.

[0032] According to one embodiment of the present invention, the self-fusion weld is a continuous integral weld or includes multiple intermittent welds distributed at intervals in sequence.

[0033] According to one embodiment of the present invention, the gap between the hole wall of the liner plate and the outer wall of the branch pipe forms a flow port, and the upper end of the hole wall of the liner plate is the initial flow point of the solder.

[0034] Alternatively, a guide surface is formed on the outer liner surface near the liner hole to guide the solder into the branch pipe hole, and a flow port is formed at the guide surface, with the place where the solder initially flows being the furthest point on the guide surface from the branch pipe hole.

[0035] According to one embodiment of the present invention, the liner includes an outer liner disposed on the outer wall of the main pipe, and the outer liner has a liner-type structure, which includes a sheet-like base and a connecting portion formed in the middle region of the sheet-like base. The sheet-like base is welded to the outer wall of the main pipe. The connecting portion protrudes to the side away from the main pipe and has a liner hole coaxially communicating with the branch pipe hole on the connecting portion. A blocking edge is formed between the sheet-like base and the outer wall of the main pipe, and the blocking edge blocks the solder flow path along the outer wall of the main pipe; wherein, the sheet-like base... The wall thickness T1 of the base satisfies 0.085d≤T1≤0.65d, and the wall thickness T2 of the connecting part also satisfies 0.085d≤T2≤0.65d; and on the main pipe section passing through the central axis of the branch pipe hole, the distance L2 from the side wall edge of the plate base to the center of the liner hole satisfies: 0.8d≤L2≤3.5d, where d is the diameter of the branch pipe hole; each branch pipe is inserted into the liner hole on the outer liner base and the inserted end extends into the corresponding branch pipe hole on the main pipe, and the branch pipe is brazed to the liner hole and the branch pipe hole.

[0036] According to an embodiment of the present invention, the projection distance H from the lowest point of the end face of the connecting part to the highest point of the main busbar in the direction of the branch pipe hole axis satisfies: 0.15d≤H≤2.2d, where d is the diameter of the branch pipe hole; the end face of the connecting part is flat or gradually slopes down towards the direction of the liner hole, and a brazing flow port is formed at the end face of the connecting part.

[0037] According to one embodiment of the present invention, the inner walls of the plate base and the liner hole are connected by a circular arc segment, the radius of the circular arc segment R≤1.5mm; the diameter d1 of the liner hole satisfies: 0.95d≤d1≤1.2d, where d is the diameter of the branch pipe hole.

[0038] According to one embodiment of the present invention, the connecting part is a flanged part formed by punching and flanging the sheet-like base; or, the connecting part and the sheet-like base are integrally formed by a warm extrusion process.

[0039] According to one embodiment of the present invention, the liner hole includes a first hole section and a second hole section that are coaxially connected in sequence along the insertion direction of the branch pipe. The inner diameter of the first hole section is larger than the inner diameter of the second hole section, and a bearing step for placing solder is formed at the transition between the first hole section and the second hole section.

[0040] In summary, the welding and fixing method and tooling for the liner and main pipe of the fluid distribution / manifold assembly provided by this invention includes a receiving groove formed on the mandrel for placing the liner. During assembly, the inner liner is placed in the receiving groove of the mandrel. When the main pipe is fitted onto the mandrel, the inner liner will adhere to the inner wall of the main pipe along with the mandrel to achieve initial positioning. Subsequently, each positioning pin passes through the branch pipe hole and the liner hole one by one from the outside to the inside of the main pipe to coaxially position both. This coaxial positioning method from the outside to the inside greatly reduces the difficulty of aligning the positioning pins in the branch pipe hole and the liner hole, making assembly not only convenient but also efficient. Furthermore, a positioning pin avoidance recess is formed at the bottom of the receiving groove on the mandrel, providing avoidance space for the positioning pin in the insertion direction. After coaxially positioning the branch pipe hole and the liner hole, the clamping assembly cooperates with the mandrel to clamp and press the liner and the main pipe wall, controlling the assembly gap between the liner and the inner wall of the main pipe to meet the capillary penetration conditions in the subsequent brazing process. This ensures that after the branch pipe is brazed, the space between the liner and the main pipe wall is filled with uniform and sufficient solder. After clamping and bonding, the liner is fixed to the main pipe wall using a self-fusion welding method, thus fixing the liner to the main pipe before brazing the branch pipe to prevent displacement during the brazing process.

[0041] To make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0042] Figure 1The diagram shown is a schematic of the structure proposed by the inventor, which uses a mandrel with a pin to weld and fix the liner and the main tube.

[0043] Figure 1A for Figure 1 The diagram illustrates how fluctuations in the spacing between branch pipe holes and pins can lead to error accumulation in the positioning method shown.

[0044] Figure 2 This is a schematic diagram of the structure of a four-way valve formed by machining the valve body component using the four-way valve body component split welding fixture structure provided by Chinese Patent CN204603644U.

[0045] Figure 2A As shown Figure 2 A structural diagram from another perspective.

[0046] Figure 3 The diagram shown is a schematic diagram of the fluid manifold assembly provided in Embodiment 1 of the present invention.

[0047] Figure 3A As shown Figure 3 A structural diagram from another perspective.

[0048] Figure 4 As shown Figure 3 A cross-sectional schematic diagram.

[0049] Figure 5 As shown Figure 4 Enlarged diagram of point B in the middle.

[0050] Figure 6A , Figure 6B , Figure 6C as well as Figure 6D This is a schematic diagram of the assembly of the outer liner and main pipe in a fluid manifold assembly provided for other embodiments.

[0051] Figure 7 The diagram shows the structure of the fluid distribution / manifold assembly when the diameter of the branch pipe hole is greater than 0.65 times the diameter of the main pipe.

[0052] Figure 8 As shown Figure 3 A schematic diagram of the inner lining plate.

[0053] Figure 8A As shown Figure 8 A cross-sectional schematic diagram.

[0054] Figure 9A and Figure 9B The diagram shown is a structural schematic of the inner liner in another embodiment.

[0055] Figure 10The diagram shown is a schematic flowchart of the welding and fixing method for the upper liner and main pipe of the fluid distribution / manifold assembly provided in Embodiment 1 of the present invention.

[0056] Figure 11 The following is an example of using Figure 10 A schematic diagram of the structure of the liner and main pipe on the fluid distribution / manifold assembly, showing the welding and fixing method used for assembly.

[0057] Figure 11A As shown Figure 11 A schematic diagram of the structure when the center positioning pin is not inserted.

[0058] Figure 12 As shown Figure 11 A schematic diagram of the structure of the mandrel.

[0059] Figure 13 The diagram shown is a schematic flow chart of a welding and fixing method for the upper liner and main pipe of a fluid distribution / manifold assembly provided in another embodiment of the present invention.

[0060] Figure 14 The following is an example of using Figure 13 A schematic diagram of the structure of the liner and main pipe on the fluid distribution / manifold assembly, showing the welding and fixing method used for assembly.

[0061] Figure 15 The diagram shown is a structural schematic of the welding fixture (excluding the locating pin) provided in Embodiment 1 of the present invention.

[0062] Figure 16 As shown Figure 15 A structural diagram from another perspective.

[0063] Figure 17 As shown Figure 15 A cross-sectional schematic diagram.

[0064] Figure 18 As shown Figure 17 A cross-sectional view along the DD line.

[0065] Figure 19 As shown Figure 17 Enlarged diagram of point E in the middle.

[0066] Figure 20 As shown Figure 15 A schematic diagram of the structure of the mandrel.

[0067] Figure 21 As shown Figure 20 A cross-sectional schematic diagram.

[0068] Figure 22 , Figure 23 , Figure 24 as well as Figure 25 The diagram shown is a schematic diagram of the mandrel structure in another embodiment of the present invention.

[0069] Figure 26 The diagram shown is a structural schematic of the pressing device on the pressing assembly in another embodiment of the present invention.

[0070] Figure 27 The diagram shown is a structural schematic of a fluid manifold assembly provided in another embodiment of the present invention.

[0071] Figure 28 As shown Figure 27 A structural diagram from another perspective.

[0072] Figure 29 The diagram shown is a schematic diagram of the fluid manifold assembly provided in Embodiment 2 of the present invention.

[0073] Figure 30 As shown Figure 29 A partial schematic diagram from another perspective.

[0074] Figure 31 As shown Figure 29 A cross-sectional schematic diagram.

[0075] Figure 32 As shown Figure 31 Assembly diagram of the main pipe and outer liner.

[0076] Figure 33 As shown Figure 30 A schematic diagram of the machining process for the radius of the arc segment on the outermost liner.

[0077] Figure 34A and Figure 34B The diagram shown is an assembly schematic of the outer bushing and the main pipe in a fluid distribution / manifold assembly provided in another embodiment of the present invention.

[0078] Figure 35A and Figure 35B The diagram shown is a partial schematic of a fluid manifold assembly provided in another embodiment of the present invention.

[0079] Figure 36 The diagram shown is a cross-sectional view of a fluid manifold assembly provided in another embodiment of the present invention. Detailed Implementation

[0080] Example 1

[0081] For fluid manifold assemblies where the main pipe requires a liner plate as a welded connector, the coaxiality between the branch pipe hole and the liner plate hole directly affects the assembly and welding of the branch pipe. Conversely, the assembly gap between the liner plate and the main pipe wall affects the distribution of solder within the gap during brazing of the branch pipe, thus impacting the airtightness and pressure resistance of the welded product. To address the coaxial positioning issue, the inventors proposed using a mandrel with a pin shaft for positioning (e.g., Figure 1and Figure 1A (As shown), but this positioning method has problems such as poor positioning coaxiality or even inability to position due to the difficulty in perfectly matching the pin spacing and branch hole spacing, difficulty in pin alignment and positioning, and insufficient radial clearance space for small-diameter main pipes, making it unsuitable.

[0082] As for Chinese patent CN204603644U, which has a similar positioning approach, such as Figure 2 and Figure 2A As shown, the four-way valve includes a valve body 100, a valve seat 200, an E-connector 300, a C-connector 400, an S-connector 500, and a D-connector 600. In Chinese Patent CN204603644U, the E, C, and S-connector positioning rods on the positioning rod assembly are respectively inserted into the ports of the E-connector 300, C-connector 400, and S-connector 500 on the four-way valve. The positioning rod assembly applies force to the three E, C, and S-connectors to ensure they pass through the connector holes on the valve body 100 and are inserted into the valve seat 200. In this design, the spacing between the connector holes on the valve body 100 used to receive the E, C, and S-connectors is fixed after machining; similarly, the spacing between the three connector positioning rods connected to the guide plate on the positioning rod assembly on the welding fixture is also fixed. To achieve proper positioning of each connector, the spacing between the connector holes and the spacing between the positioning rods must be consistent. However, due to dimensional and geometric tolerances during machining, this consistency is impossible to achieve, leading to interference between some connectors and the connector holes on the main pipe, preventing assembly. Similarly, the same problem exists for the S-connector positioning posts and D-connector positioning posts fixed to the lower horizontal plate. Furthermore, as... Figure 2 As shown in the patent, since the positioning rod is always connected to the three ESC connectors, its own weight only acts on the three ESC connectors, causing the three connectors to be pressed tightly into the valve seat 200 (e.g., Figure 2 (The direction indicated by the middle arrow F). However, for valve seat 200 and valve body 100, there is no mechanism to clamp them together, resulting in a large gap after assembly. This leads to welding quality problems such as incomplete welds and broken welds during subsequent brazing of branch pipes. In addition, although this patent aims to achieve consistent clamping of the three pipes through the synchronous pressing of the positioning assembly, in reality, due to factors such as dimensional tolerances and component wear and deformation, the distance between each pipe and its corresponding positioning rod varies. This difference causes some positioning rods to have free travel during clamping, thus affecting the consistency of clamping.

[0083] In view of this, this embodiment provides a welding and fixing method for the upper liner and main pipe of a fluid manifold assembly, which is convenient to position, has high positioning coaxiality, and ensures that the gap between the liner and the main pipe wall after positioning meets the brazing requirements. For example... Figures 3 to 9BAs shown, the fluid manifold assembly includes a main pipe 10, a liner, and multiple branch pipes 30. The main pipe 10 has at least three branch pipe holes 101 for welding the branch pipes 30, and the diameter d of the branch pipe holes is less than 0.65 times the diameter D of the main pipe. The liner is arc-shaped and has liner holes. In this embodiment, liners are provided on both the inner and outer walls of the main pipe 10. For ease of description, the liner mounted on the inner wall of the main pipe 10 is the inner liner and is marked with the number 20, and the liner holes on the inner liner 20 are marked with the number 201; the liner mounted on the outer wall of the main pipe 10 is the outer liner and is marked with the number 20', and the corresponding liner holes on it are marked with the number 201'.

[0084] For the fluid manifold assembly provided in this embodiment, the inner liner 20 is provided to address the welding problem caused by insufficient welding strength of the branch pipe 30. After the inner liner 20 is provided, the liner hole 201 on it, together with the branch pipe hole 101, will provide welding depth for the branch pipe 30, ensuring that the connection strength of the branch pipe 30 after welding meets the requirements (e.g., Figure 5 (As shown). The outer liner 20' is designed to address the welding problem of incomplete or broken welds on the critical weld seam between the branch pipe outer wall and the branch pipe hole caused by the flow of solder along the curved outer wall of the main pipe 10 during the brazing of the branch pipe 30.

[0085] In this embodiment, the outer liner 20' is located at the lowest point A of the busbar on the branch hole 101, around the periphery of A' and attached to the outer wall of the main pipe 10. A blocking edge 202' is formed between the outer liner 20' and the outer wall of the main pipe 10. The blocking edge 202' surrounds the outer periphery of the branch hole 101 in whole or in part to block the solder flow path along the outer wall of the main pipe. The side of the outer liner 20' near the branch hole 101 forms a solder flow port 203' pointing towards the branch hole 101. To prevent the solder 40 (such as ring solder) from flowing along the surface of the outer liner 20' during brazing, such as... Figure 4 and Figure 5 As shown, on the main section through the central axis of the branch pipe hole 101, a rectangular coordinate system is constructed with the highest point of the generatrix on the main pipe 10 as the origin O, the central axis of the branch pipe 30 as the positive direction of the Y-axis, and the radial direction of the main pipe 10 as the X-axis; the ordinate y of the initial flow point 204' of the solder at the flow port 203' falls in the positive direction of the Y-axis.

[0086] In some applications, the diameter of branch pipe 30 will be larger; correspondingly, the diameter of branch pipe hole 101 on main pipe 10 will also be larger, such as... Figure 7The diameter of the branch pipe hole 101 shown is greater than or equal to 0.65 times the diameter of the main pipe 10. In this case, due to the large height difference between the highest and lowest points of the generatrix on the branch pipe hole 101, if an outer liner 20' is directly installed around the through-hole-shaped branch pipe hole 101, the thickness H0 of the outer liner 20' must be very thick to satisfy the condition that the longitudinal coordinate y-coordinate of the initial flow point of the solder at the flow port 203' falls in the positive direction of the Y-axis. The thicker the outer liner 20', the longer the solder path at the flow port 203' will be, and the greater the impact of the heat absorption of the outer liner 20' itself on the solder flowability, thus affecting the solder penetration effect within the branch pipe hole. Furthermore, an excessively thick outer liner 20' during autofusion welding will also make it difficult to penetrate and fix to the outer wall of the main pipe; in addition, an excessively large branch pipe hole diameter will also cause the inner and outer liners to be difficult to position for autofusion welding due to insufficient space. Therefore, in this embodiment, the diameter d of the branch pipe hole 101 is less than 0.65 times the diameter D of the main pipe.

[0087] For the outer liner 20', the capillary penetration caused by the assembly gap between the outer liner 20' and the outer wall of the main pipe 10 disappears at the blocking edge 202'. During brazing, the flow path of the solder along the outer wall of the main pipe 10 is blocked at the blocking edge 202', thus allowing the solder 40 to flow only towards the side of the outer liner 20' closer to the branch hole 101. In this embodiment, after the welding fixture presses the outer liner 20' and the main pipe 10 together, a self-fusion weld 205' is formed between the outer liner 20' and the outer wall of the main pipe 10, with the extension direction being approximately the same as the side wall edge of the outer liner 20'. The self-fusion weld 205' not only achieves the welding and fixing of the outer liner 20' and the main pipe 10, but also acts as the blocking edge 202' to block the brazing gap caused by the assembly between the outer liner 20' and the outer wall of the main pipe 10, thereby preventing the solder from penetrating into the gap located outside the self-fusion weld 205' during subsequent brazing. Specifically, the self-fusion weld 205' is a continuous, integral weld extending along the axial direction of the main pipe, where the blocking edge 202' of the outer liner 20' will be formed. However, the present invention is not limited thereto. In other embodiments, the self-fusion weld may also be formed at the sidewall edge of the outer liner 20' away from the branch pipe hole (e.g. Figure 6A (as shown) or formed on the side wall edge of the outer liner 20' near the branch hole (e.g. Figure 6B (As shown). Alternatively, in other embodiments, the self-fusion weld 205' may also include a plurality of intermittent welds distributed at intervals in sequence, the intermittent welds and the sidewall edge of the outer liner 20' away from the branch pipe hole together forming a blocking edge 202', as shown. Figure 6C As shown.

[0088] In this embodiment, as Figure 4 and Figure 5As shown, a solder inlet 203' is formed at the wall of the liner hole 201' on the outer liner plate 20', with the solder flow direction pointing towards the branch pipe hole 101. The solder inlet 203' quickly guides the solder into the branch pipe hole 101 to shorten the solder flow path, thereby allowing the solder to fully and evenly penetrate into the critical gaps between the outer wall of each branch pipe 30 and the corresponding branch pipe hole 101 on the main pipe 10, ensuring that the brazing strength, pressure resistance, and airtightness of the branch pipes can all meet the requirements. In this embodiment, the upper end of the side wall of the liner hole 201' on the outer liner plate 20' is the initial solder flow point 204'. However, the present invention does not limit this in any way. In other embodiments, such as Figure 6D As shown, a guide surface for guiding solder into the branch pipe hole 101 can also be formed on the surface of the outer liner 20' near the liner hole 201'. A flow port 203' is formed at the guide surface, and the furthest point on the guide surface from the branch pipe hole 101 is the initial flow point of the solder 204'.

[0089] like Figure 3 and Figure 3A As shown, the fluid manifold assembly provided in this example is a water distribution / manifold used in fan coil units or combined air conditioning units in water systems. In this fluid manifold assembly, a large number of branch pipes 30 are connected to the main pipe 10. Correspondingly, as... Figure 8 and Figure 8A As shown, the inner wall of the main pipe 10 is provided with a plurality of inner lining plates 20, and each inner lining plate 20 has two lining plate holes 201; the outer wall of the main pipe 10 is also provided with a plurality of outer lining plates 20', and each outer lining plate 20' also has two lining plate holes 201'. However, the present invention does not limit the number of lining plate holes in each lining plate. In other embodiments, the lining plate may also be a single-hole lining plate with only one lining plate hole (e.g., Figure 9A As shown), in this case, a single-hole liner will be independently installed on the inner and outer walls of the main pipe where each branch pipe hole is located; alternatively, the liner can also be a one-piece multi-hole liner with two or more liner holes (such as...). Figure 9B ).

[0090] In this embodiment, the inner liner 20 and the outer liner 20' have essentially the same structure; both are rectangular arc-shaped plates. However, the width of the inner liner 20 is greater than that of the outer liner 20', and the liner hole 201' on the outer liner is slightly larger than that on the inner liner to facilitate the insertion of the positioning pin. However, this invention does not impose any limitations on this. In other embodiments, the edge shapes of the inner and outer liners may also be different; for example, one may have a rounded edge, while the other may have a rectangular or elliptical edge, or other shapes.

[0091] Although this embodiment uses a fluid manifold assembly including an inner and outer liner as an example to describe in detail the welding and fixing method of the liner and the main pipe, and the corresponding tooling, the present invention does not limit it in any way. In other embodiments, the welding and fixing method and tooling of the liner and the main pipe provided by the present invention are also applicable to the assembly of fluid manifold assemblies having only an inner liner.

[0092] It should be noted that the welding and fixing method for the liner and main pipe provided by this invention aims to achieve coaxial positioning and fixing of the liner and main pipe before brazing the branch pipes. After assembling and connecting the liner and main pipe using the welding and fixing method provided by this invention, the branch pipes, liner, and main pipe need to be brazed for sealing. For example, after assembling multiple branch pipes, all branch pipes, all liner plates, and main pipes are integrally welded together by furnace brazing. However, this invention does not limit the subsequent brazing method between the liner and main pipe. In other embodiments, other brazing methods such as flame brazing can also be used for sealing.

[0093] This embodiment uses Figure 3 and Figure 3A Taking the fluid manifold assembly with liners on both the inner and outer walls of the main pipe 10 as an example, and combining it with... Figures 10 to 12 This embodiment provides a detailed method for welding and fixing the upper liner and main pipe of a fluid manifold assembly. In this embodiment, the welding and fixing of the upper liner and main pipe of the fluid manifold assembly includes the following steps: The inner liner 20 to be fixed is placed in a receiving groove 21 on the mandrel 2. The receiving groove 21 has positioning pin clearance recesses 22 corresponding to multiple branch pipe holes 101 (step S10). The main pipe 10 is then fitted onto the outside of the mandrel 2 after the inner liner 20 is placed, so that the arcuate surface of the inner liner 20 fits against the inner wall of the main pipe 10 and each liner hole 201 is approximately opposite to the corresponding branch pipe hole 101 (step S20). After the main pipe 10 is fitted onto the outside of the mandrel 2, the arcuate surface of the outer liner 20' to be placed is fitted against the outer wall of the main pipe 10, and each liner hole 201' is approximately opposite to the corresponding branch pipe hole 101 (step S30). Each positioning pin 3 passes through the liner hole 201', branch pipe hole 101, and liner hole 201 on the outer liner plate and inner liner plate, respectively, from the outside to the inside of the main pipe 10, and is inserted into the positioning pin clearance recess 22 on the mandrel 2 to position the outer liner plate 20', the main pipe 10, and the inner liner plate 20 (step S40). After the positioning pins 3 are positioned, the liner plates on both sides are pressed tightly against the pipe wall of the main pipe 10 using a clamping assembly (step S50). Finally, the tightly fitted outer liner plate 20', the pipe wall of the main pipe 10, and the inner liner plate 20 are connected by self-fusion welding (step S60); the self-fusion welding can be any of the welding methods such as resistance welding, laser welding, argon arc welding, and flash welding.

[0094] To assemble multiple inner lining plates 20 onto the inner wall of the main pipe 10, step S10 uses a mandrel 1 with a receiving groove 21 as an assembly tool. The multiple inner lining plates 20 to be assembled are placed one by one into the receiving groove 21 on the mandrel. The placement of the multiple inner lining plates 20 onto the inner wall of the main pipe 10 is achieved through the assembly of the main pipe 10 and the mandrel 2 in step S20. Although this embodiment uses step S20, where the main pipe is fitted over the mandrel 2, as an example, the present invention does not limit this. In other embodiments, the mandrel can also be moved to insert it into the main pipe.

[0095] After the initial placement of multiple inner lining plates 20 and multiple outer lining plates 20' on the main pipe, step S40 is executed. Multiple positioning pins 3 are inserted sequentially from the outside to the inside of the main pipe 10. Each positioning pin 3 passes through the lining plate hole 201' on the outer lining plate, the branch pipe hole 101, and the lining plate hole 201 on the inner lining plate, and is inserted into the positioning pin avoidance recess 22 located at the bottom of the receiving groove 21 on the mandrel 2. Compared to the positioning method of a fixed assembly structure of pins and mandrels proposed by the inventors, in this embodiment, each positioning pin 3 is inserted independently from the outside to the inside. This positioning method allows the assembly position of the positioning pins 3 to be freely adjustable, and the center distance of the positioning pins can well adapt to the dimensional tolerance of the branch pipe hole and the cumulative error of the center distance of the branch pipe hole, thereby achieving coaxial assembly of the lining plate hole and the branch pipe hole. In this embodiment, the free insertion of the positioning pins from the outside to the inside effectively solves the positioning interference problem existing in the positioning method of the mandrel with pins proposed by the inventors and in Chinese patent CN204603644U. In addition, the free insertion of the locating pin 3 from the outside to the inside greatly reduces the difficulty of aligning the locating pin and improves assembly efficiency, while also significantly improving the accuracy of coaxial positioning.

[0096] Furthermore, to ensure that the locating pin can be aligned with the liner hole 201 inserted into the inner liner 20, the width of the receiving groove 21 on the mandrel is slightly larger than the width of the inner liner 20, so that a positioning adjustment gap 23 is formed between the side wall of the inner liner 20 and the inner wall of the receiving groove 21 for adjusting the coaxiality of the liner hole 201. The positioning adjustment gap 23 provides space for the displacement of the inner liner 20 within the receiving groove 21, thereby eliminating the problem of the inner liner 20 getting stuck and unable to achieve liner hole positioning due to dimensional tolerances, geometric tolerances, and other factors during machining.

[0097] After the positioning pin coaxially positions the branch pipe hole 101 and the liner holes on both side liner plates, step S50 will use a clamping assembly to press the inner liner plate 20 and the outer liner plate 20' against the pipe wall of the main pipe 10 to control the assembly gap between the side liner plates and the main pipe. Specifically, as shown... Figure 11As shown, in this step, the clamping assembly applies a clamping force F1 from the outside of the main pipe 10 towards its inside; simultaneously, the mandrel 2 supports the inner liner 20, applying a supporting force F2 towards the outside of the main pipe 10. The clamping force F1 and the supporting force F2, acting in opposite directions, cause the clamping assembly and the mandrel to clamp and press the outer liner 20', the main pipe 10, and the inner liner 20, thereby controlling the assembly gap between the two liner plates and the main pipe wall, providing conditions for capillary penetration of the solder during subsequent brazing, so that the airtightness and pressure resistance of the brazed fluid manifold assembly can meet the system requirements. In this embodiment, the size of the receiving groove 21 on the mandrel matches the size of the inner liner 20. This matching is not only manifested in the fact that the width of the receiving groove 21 is slightly larger than the width of the inner liner 20 to provide a positioning adjustment gap 23 between the two. Furthermore, this size matching is also reflected in the fact that the thickness of the inner liner 20 is slightly greater than the depth of the receiving groove 21. This setting ensures that the inner liner 2 fits against the inner wall of the main pipe 10, while also allowing the surface of the mandrel on the outer periphery of the receiving groove 21 to fit well against the inner wall of the main pipe 10. When pressed, the surface of the mandrel 2 supports the main pipe 10 to prevent it from denting under the action of the pressing force F1.

[0098] In this embodiment, in step S50, the clamping assembly 4 indirectly applies force to the positioned outer liner 20' through the positioning pin 3. Specifically, the positioning pin 3 has a shoulder 32 that abuts against the outer liner 20'. The clamping assembly 4 applies force to each positioning pin 3 simultaneously through the clamping plate, and the shoulder 32 on the positioning pin 3 clamps the positioned outer liner 20', the pipe wall of the main pipe 10, and the inner liner 20 from the outside to the inside. However, the present invention does not limit this. In other embodiments, the clamping assembly may also act on each positioning pin individually; or, the clamping assembly may directly abut against the outer liner to provide clamping force. To compensate for the height difference between the clamping plate and the end face of each positioning pin clamping section to improve the clamping consistency of all positioning pins, preferably, the clamping assembly may also be configured to clamp each positioning pin or the outer liner in an elastic manner.

[0099] In the welding and fixing method for the liner and main pipe of the fluid manifold assembly provided in this example, step S10 achieves the initial positioning of the inner liner 20 on the inner wall of the main pipe 10 based on the receiving groove 21 on the mandrel, especially the synchronous positioning of multiple inner liner 20s. In step S30, the independent insertion of multiple positioning pins from the outside to the inside effectively avoids the influence of the dimensional tolerance of the fixed pin shaft and the cumulative error of the pin shaft center distance on the assembly of the main pipe and the liner, thereby significantly improving the coaxial positioning accuracy of the branch pipe hole 101 and the liner hole 201. In step S50, the mandrel 2 and the clamping assembly 4 are opposite each other, and the two together clamp the inner and outer liner plates and the main pipe 10 to achieve control of the assembly gap between the liner plate and the main pipe, thereby effectively solving the problem of weld failure caused by excessive gap. That is, the welding and fixing method provided in this embodiment effectively solves the problems of difficult assembly of inner liner plates, poor coaxiality of liner hole and branch pipe hole positioning, and broken welds and incomplete welds after brazing of branch pipes in the processing of fluid manifold assemblies.

[0100] Although this embodiment uses the example of both the inner and outer walls of the main pipe 10 being lined with plates, the present invention does not impose any limitations on this. In other embodiments, if the fluid manifold assembly only includes an inner liner disposed on the inner wall of the main pipe, then step S30 is not required; that is, after the main pipe is fitted onto the mandrel in step S20, step S40 (inserting each positioning pin one by one from the outside to the inside) can be performed, as shown in the flowchart below. Figure 13 As shown. At this time, each positioning pin 3 will pass through the corresponding branch pipe hole 101 and liner hole 201 from the outside to the inside of the main pipe 10 and be inserted into the positioning pin clearance recess 22 on the mandrel 2, so as to coaxially position the branch pipe hole 101 and the corresponding liner hole 201 on the inner liner, as shown. Figure 14 As shown. Correspondingly, in step S50, the clamping assembly indirectly applies force to the outer wall of the main pipe 10 through the shoulder on the positioning pin, and together with the mandrel 2, clamps the main pipe 10 and the inner liner 20. Similarly, for the fluid distribution / manifold assembly of this structure, in other embodiments, the clamping assembly can also directly apply force to the outer wall of the main pipe to achieve its clamping with the inner liner.

[0101] Corresponding to the above-described welding and fixing method, this embodiment also provides a welding and fixing fixture for welding and fixing the liner and main pipe on the fluid distribution / manifold assembly. For example... Figures 15 to 21As shown, the welding fixture includes a fixture support 1, a mandrel 2, multiple locating pins 3, and a clamping assembly 4. The mandrel 2 is mounted on the fixture support 1, and during assembly, one end of the mandrel 2 is free to allow the main pipe 10 to be fitted inside. The mandrel 2 has a receiving groove 21 for placing the inner liner 20, and the receiving groove 21 has locating pin clearance recesses 22 corresponding to multiple branch pipe holes 101. After the main pipe 10 is fitted with the mandrel 2, each locating pin 3 passes through the corresponding branch pipe hole 101 and liner hole 201 one by one from the outside of the main pipe 10 and is inserted into the locating pin clearance recess 22 on the mandrel 2 to position the liner and the main pipe 10. The clamping assembly 4 is vertically mounted on the fixture support 1, and the clamping assembly 4 abuts against any of the multiple locating pins 3, the outer wall of the main pipe 10, or the outer liner 20' to clamp the positioned liner and the pipe wall of the main pipe 10.

[0102] In this embodiment, the tooling bracket 1 includes a base 11 and a first bracket 12 and a second bracket 13 located at both ends of the base 11. The connecting end 2A of the mandrel 2 has a connecting hole 2A1, which is rotatably connected to the first bracket 12 via a pin 15. The mandrel 2 rotates relative to the first bracket 12 with the pin 15 as a fulcrum. The movable end 2B of the mandrel can be detachably engaged in a slot 131 on the second bracket 13. During assembly, the movable end 2B of the mandrel detaches from the slot 131 on the second bracket, allowing the main tube 10 to be inserted. The rotatable connection between the connecting end 2A of the mandrel and the first bracket 12 allows the mandrel 2 to unfold along the width of the tooling bracket 1, shortening the length of the tooling bracket when the main tube 10 is inserted, thereby reducing the overall working space of the tooling. However, this invention does not impose any limitations on this. In other embodiments, the second support and base can be configured as detachable or sliding structures. After the second support separates from the base or slides relative to the base to allow the movable end of the mandrel to be in a free state, the main pipe is inserted from the movable end of the mandrel along the length of the tooling support. Alternatively, in other embodiments, the connecting end of the mandrel can also be detachably connected to the first support, meaning both ends of the mandrel can be detachably connected to the tooling support. When the liner and main pipe positioned by the current mandrel are being welded on the self-fusion welding tooling support of the welding equipment, the operator can assemble another main pipe and its two side liners on another mandrel. After welding is completed, the current mandrel and the main pipe after welding the liner are removed together from the tooling support; then, another mandrel, along with another main pipe and its two side liners, is assembled onto the tooling support for subsequent pressing and welding processes. The detachable nature of both ends of the mandrel allows the welding of the main pipe and liner on the current mandrel to be synchronized with the assembly of the other main pipe and liner on the other mandrel, thereby significantly improving processing efficiency.

[0103] In this embodiment, the receiving groove 21 on the mandrel 2 is an axial through groove extending from one end to the other along the axial direction of the mandrel 2, and the size of the receiving groove 21 matches the size of the inner liner 20. The axially connected receiving groove 21 allows the welding fixture provided in this embodiment to be adapted to inner liner 20 of different lengths; specifically, it can be used to assemble the liner structure with two liner holes provided in this embodiment, and it can also be used to assemble single-hole liner plates or multi-hole integrated liner plates with more liner holes and longer lengths. For the receiving groove 21 of this structure, its matching with the inner liner 20 in terms of size is mainly reflected in the circumferential width and groove depth. Specifically, the circumferential width of the receiving groove 21 is slightly larger than the width of the inner liner 20, so that a positioning adjustment gap 23 is formed between the side wall of the inner liner 20 and the inner wall of the receiving groove 21. This provides adjustment space for the movement of the inner liner 20 within the receiving groove 21 during positioning, thereby achieving coaxiality adjustment of the liner hole 201 and the branch pipe hole 101 on the inner liner. The depth of the receiving groove 21 is slightly less than the thickness of the inner liner 20. This design ensures that after the main pipe 10 is inserted, not only can the inner liner 20 fit well against the inner wall of the main pipe 10, but the surface of the mandrel located outside the receiving groove 21 can also fit well against the inner wall of the main pipe 10 to support it and prevent deformation during compression. However, this invention does not limit the specific structure of the receiving groove. In other embodiments, if the inner liner is short in length, such as a single-hole liner or a one-piece liner with a small number of holes, multiple accommodating grooves 21 spaced apart along the axial direction can also be provided on the mandrel (e.g. Figure 22 (As shown); at this time, a positioning adjustment gap is also formed between the two ends of each inner liner and the inner wall of the end of the receiving groove, which provides space for the axial displacement of the inner liner in the receiving groove.

[0104] In this embodiment, as Figure 15 and Figure 21 As shown, the locating pin clearance recess 22 is a clearance groove formed at the bottom of the receiving groove 20 and extending axially, to improve the versatility of the mandrel by adapting to main pipes with different branch hole spacings. However, the present invention does not limit this. In other embodiments, when multiple receiving grooves on the mandrel are distributed axially at intervals (e.g. Figure 22 As shown), the positioning pin clearance recess 22 is also a plurality of clearance grooves formed at the bottom of each receiving groove and extending axially. Alternatively, in other embodiments, the positioning pin clearance recess 22 on the mandrel is a plurality of clearance holes (e.g., distributed corresponding to the plurality of branch holes on the main pipe and formed at the bottom of the receiving groove) Figure 23 (As shown); the clearance hole can be either a blind hole or a through hole that penetrates the mandrel.

[0105] After the positioning pin 3 positions the liner 20 and the main pipe 10, the clamping assembly 4 moves along the tooling bracket toward the mandrel 2 to clamp the outer liner 20', the main pipe 10, and the inner liner 20. Specifically, in this embodiment, the positioning pin 3 includes an insertion section 33, a shoulder 32, and a clamping section 31 connected in sequence. The insertion section 33 passes through the liner hole 201' on the outer liner 20', the branch pipe hole 101 on the main pipe 10, and the liner hole 201 on the inner liner 20 and is inserted into the positioning pin clearance recess 22 on the mandrel 2. The cross-sectional diameter of the shoulder 32 is larger than that of the insertion section 33 to abut against the outer liner 20'. The clamping assembly 4 includes multiple cylinders 41 mounted on the tooling bracket 1 and a clamping plate 42 connected to the multiple cylinders 41. Under the action of the multiple cylinders 41, the clamping plate 42 abuts against the clamping section 31 of each positioning pin 3, and applies a clamping force F1 from the outside to the inside to the outer liner 20' through the shoulder 32, and under the action of the supporting force F2 provided by the mandrel 2 (as shown in the image). Figure 11 As shown, the clamping assembly 4, together with the outer liner 20', the main pipe 10, and the inner liner 20, presses together. In this embodiment, the clamping assembly 4 indirectly clamps the main pipe 10 and the inner and outer liners via the shoulder 32 on the positioning pin 3. However, this invention does not limit this in any way. In other embodiments, multiple clamping devices may be provided below the clamping plate, each clamping device directly abutting against the corresponding outer liner to apply clamping force.

[0106] To eliminate the impact of the height difference between the end faces of the clamping sections 31 of the clamping plate 42 and each locating pin on the clamping consistency, preferably, the clamping assembly 4 further includes an elastic element 43 disposed on the side of the clamping plate 42 near the mandrel 2. The elastic element 43 deforms during the clamping stroke of the cylinder 41 to compensate for the height difference between the end faces of the clamping sections 31 of the clamping plate 42 and the locating pins, thereby improving the clamping consistency of all locating pins. In this embodiment, the elastic element 43 is an elastic plate made of a polymer compound such as polyurethane. However, the present invention does not limit this in any way. In other embodiments, such as Figure 26 As shown, an elastic clamping device 43' can also be provided below the clamping plate. The elastic clamping device 43' includes a connecting plate 431' connected to the clamping plate 42, a compression spring 432', and a clamping end plate 433'.

[0107] like Figure 15 and Figure 16As shown, the clamping assembly 4 includes two synchronously controlled cylinders 41, which are respectively mounted on the first bracket 12 and the second bracket 13. The two cylinders 41 are mounted on the brackets in the same way; the cylinder 41 mounted on the first bracket 12 will be described in detail as an example. Specifically, the cylinder body 411 of the cylinder 41 is mounted on the top of the first bracket 12, and the piston rod 412 passes through the top of the first bracket 12 and connects to one end of the clamping plate 42. The first bracket 12 is also provided with two guide posts 14 located around the piston rod 412 and passing through the clamping plate 42. The piston rod 412 drives the clamping plate 42 axially under the guidance of the two guide posts 14. Similarly, the piston rod 412 of the cylinder 41 mounted on the second bracket 13 is connected to the other end of the clamping plate 42 to synchronously drive the clamping plate 42; the piston rod 412 is also similarly surrounded by two guide posts 14 passing through the clamping plate 42 to axially guide the piston rod. However, the present invention does not impose any limitations on this. In other embodiments, the number of cylinders in the clamping assembly may be more than three, with multiple cylinders distributed sequentially along the length of the clamping plate; for example, a top plate parallel to the clamping plate may be set between two supports, with multiple cylinders sequentially installed on the top plate along the length, and the piston rod of each cylinder passing through the top plate and connected to the clamping plate to synchronously drive the clamping plate to rise and fall; the longer the clamping plate is, the more cylinders are required.

[0108] After the clamping assembly 4 clamps and positions the main pipe 10 and the liners on both sides thereon, the welding equipment uses a self-fusion welding method to connect the tightly fitting liners and the inner wall of the main pipe 10. To prevent the inner liner 20 from being penetrated and sticking to the mandrel 2 during self-fusion welding, in this embodiment, a welding clearance groove 24 is formed in the area covered by the inner liner 20 on the mandrel 2. The welding clearance groove 24 is located on both sides of the positioning pin clearance recess 22 and extends along the axial direction of the mandrel 2. During welding, the welding equipment applies heat to the inner liner 20 and the pipe wall of the main pipe 10 at the location of the welding clearance groove 24 to perform self-fusion welding. At this time, even if the inner liner 20 is penetrated, the mandrel 2 will not be melted and stick to it.

[0109] Figure 24 The diagram shown is a schematic diagram of the structure of a mandrel provided in another embodiment of the present invention. In this structure, multiple sets of positioning areas 2C are formed on the mandrel 2 along its circumference. Each positioning area 2C includes a receiving groove 21 and a positioning pin avoidance recess 22 formed at the bottom of the receiving groove 21. The widths of the receiving grooves 21 in the multiple positioning areas 2C are different so that the mandrel can be used for the assembly of inner liner plates of different widths.

[0110] Figure 25The diagram shows a schematic of a mandrel provided in another embodiment of the present invention. In this structure, the cross-section of the mandrel 2 is semi-circular, and the surface of the mandrel 2 opposite to the receiving groove 21 is a plane 25. This arrangement can reduce the volume and weight of the mandrel. Furthermore, the mandrels on both sides of the receiving groove can also be machined into planes to further reduce the volume and weight of the mandrel.

[0111] Although this embodiment is based on Figure 3 and Figure 3A The fluid manifold assembly shown is an example of a fluid distribution / manifold assembly used in a fan coil unit or combined air conditioning unit in a water system. However, the present invention is not limited thereto. In other embodiments, the fluid manifold assembly used in the evaporator or condenser of a refrigerant system (such as...) Figure 27 and Figure 28 Alternatively, the welding and fixing method and tooling for the upper liner and main pipe of the fluid distribution / manifold assembly provided by this invention can be used for assembly.

[0112] Example 2

[0113] This embodiment is basically the same as Embodiment 1 and its variations, except that the structure of the outer liner 20' is different, while the assembly method of the outer liner 20' can still adopt the assembly process and tooling in Embodiment 1. In this embodiment, while preventing the solder from flowing along the curved outer wall of the main pipe 10, the liner hole 201' on the outer liner 20', together with the branch pipe hole 101 and the liner hole 201 on the inner liner, provides welding depth for the branch pipe 30.

[0114] Specifically, such as Figures 29 to 33As shown, in the fluid distribution / manifold assembly provided in this embodiment, the outer liner 20' is a liner-type structure and includes a sheet-like base 206' and a connecting portion 207' formed in the middle region of the sheet-like base. The sheet-like base 206' is welded to the outer wall of the main pipe 10. The connecting portion 207' protrudes to the side away from the main pipe and has a liner hole 201' coaxially connected to the branch pipe hole 101. A blocking edge 202' is formed between the sheet-like base 206' and the outer wall of the main pipe 10. The blocking edge 202' blocks the solder flow path along the outer wall of the main pipe 10. The wall thickness T1 of the plate-shaped base 206' satisfies 0.085d≤T1≤0.65d, and the wall thickness T2 of the connecting part 207' also satisfies 0.085d≤T2≤0.65d. Furthermore, on the main pipe section passing through the central axis of the branch pipe hole 101, the distance L2 from the edge of the side wall of the plate-shaped base 206' to the center of the liner hole 201' satisfies 0.8d≤L2≤3.5d, where d is the diameter of the branch pipe hole (approximately the outer diameter of the branch pipe). The branch pipe 30 is inserted into the liner hole 201' on the outer liner plate 20', and the inserted end extends through the branch pipe hole 101 on the main pipe 10 to the liner hole 201 on the inner liner plate. The branch pipe 30 is brazed to the liner hole 201' on the outer liner plate, the branch pipe hole 101, and the liner hole 201 on the inner liner plate.

[0115] Admittedly, in the fluid manifold assembly provided in Embodiment 1, the inner liner 20 has significantly improved the welding strength of the branch pipe 30. However, some pipelines in the refrigeration system have stringent requirements for the refrigerant flow area, such as pipelines connecting the compressor input and output ends. The addition of the inner liner 20 will affect the flow area of ​​the main pipe 10 to some extent, which may lead to insufficient welding depth of the branch pipe 30 even after the inner liner is added. Although some people on the market use the method of directly flanging the branch pipe hole or adding connecting blocks to improve the welding depth of the branch pipe, directly flanging the branch pipe hole has the problems of low height and easy cracking of the flanged part. The welding depth provided by using the thickness of the connecting block itself has the problems of the connecting block being too large and difficult to heat. During brazing, the heat absorption is too large, which affects the temperature of the solder, resulting in poor solder flow and difficulty in penetrating into the critical weld at the end of the penetration path. Ultimately, this leads to welding problems such as incomplete welding and broken welding in the welded product. Therefore, this embodiment provides an improved structure for the outer liner 20'. In addition to preventing the solder from flowing along the outer wall of the main pipe during brazing as described in Embodiment 1, the liner hole 201' on the outer liner, together with the branch pipe hole 101 and the branch pipe hole 201 on the inner liner, provides welding depth for the main pipe 30.

[0116] As for the outer liner 20', it is located on the outer wall of the main pipe 10, and the depth of the liner hole 201' is not limited by the flow area. Furthermore, the split structure of the outer liner 20' and the main pipe 10 means that the forming height of the connecting part 207' on the outer liner 20' (i.e., the depth of the liner hole 201') is no longer limited by the material and shape of the main pipe 10. Its height can be matched and processed based on the welding strength requirements of the branch pipe 30, thereby effectively solving the problems of insufficient welding depth of the branch pipe 30 after adding the inner liner and the low flange height and easy cracking of the flanged part due to the direct flange of the branch pipe hole. Furthermore, similar to Embodiment 1, the setting of the outer liner 20' also changes the flow mode of the solder on the outer wall of the main pipe 10, changing it from a sliding based on gravity component to a flow mode mainly based on capillary penetration formed by the gap between the plate base 206' and the outer wall of the main pipe 10. At the blocking edge 202', there is no longer a gap or the gap is blocked between the sheet base 206' and the outer wall of the main pipe 10. The capillary penetration of the solder disappears at this point, so that the solder flow path on the outer wall of the main pipe 10 is cut off by the blocking edge 202'. The solder will not penetrate through the gap between the sheet base 206' outside the blocking edge 202' and the outer wall of the main pipe, thus solving the problem of solder flowing along the outer wall of the main pipe. In other words, the solder that seeps through from the liner hole 201' on the outer liner plate and the gap 102 between the outer wall of the branch pipe 30 fills the gap 103 between the plate base 206' inside the blocking edge 202' and the outer wall of the main pipe. It can only gradually seep into the critical gap 104 between the branch pipe hole 101 and the outer wall of the branch pipe 30, and the gap 105 between the liner hole 201' on the inner liner plate and the outer wall of the branch pipe 30. This ensures that the critical gaps 104 and 105 are filled with sufficient and uniform solder, so that the branch pipe 30 can meet the system piping requirements well in terms of connection strength, pressure resistance and air tightness after welding.

[0117] Furthermore, the limiting of the thickness of the sheet-like base, the connecting portion 207' protruding from the central region of the sheet-like base 206', and the wall thickness of the sheet-like base 206' and the connecting portion 207', while satisfying the connection strength of the outer liner 20', greatly reduces its volume to minimize the heat absorbed during brazing, significantly reducing the impact of its heat absorption on the solder flow properties so that the solder can penetrate into the critical gaps 104 and 105 located at the end of the penetration path. Preferably, 0.25d≤T1≤0.45d and 0.25d≤T2≤0.45d are set. However, the present invention does not impose any limitation on this. In other embodiments, the ratio between the wall thickness T1 of the sheet-like base and the wall thickness T2 of the connecting portion and the diameter d of the branch pipe hole can also be other values ​​between 0.085 and 0.65. Specifically, the wall thickness T2 of the connection refers to the wall thickness of the area where the liner hole 201' provides an effective welding depth for the branch pipe 30 to form the gap 102 (i.e., the straight section of the liner hole). In this embodiment, as... Figure 31 and Figure 32 As shown, the outer diameter of the connecting part 206' and the diameter of the liner hole 201' are basically equal, therefore the wall thickness T2 of the connecting part is the wall thickness at the end face of the connecting part. However, the present invention does not limit this in any way. In other embodiments, when the end face of the connecting part is inclined, such as... Figure 34A As shown, the wall thickness T2 of the connecting part refers to the wall thickness at the lowest point of the connecting part's end face. Or, as... Figure 34B As shown, the wall thickness T2 of the connecting part refers to the wall thickness at the second connecting hole section 2012'.

[0118] The central region of the sheet-like base 206' described in this invention is not the area located at the center of the sheet-like base, but refers to the entire area located inside the periphery of the sheet-like base. Although this embodiment is described with the extension line of the branch pipe hole 101 being substantially perpendicular to the axis of the main pipe 10 as an example, this invention does not limit it in any way. The outer liner provided by this invention is also applicable to fluid manifold assemblies where the axis of the branch pipe hole and the axis of the main pipe deviate, such as... Figure 36 As shown.

[0119] In the fluid distribution / manifold assembly provided in this embodiment, the separate structure of the outer liner 20' and the main pipe 10 allows the outer liner 20' to be processed independently, removing the height restriction of the connecting part 207' by the main pipe 10 and making the processing of the outer liner 20' more diverse. In this embodiment, the connecting part 207' and the sheet base 206' are integrally formed by a warm extrusion process. In the warm extrusion process, the height of the connecting part 207' and the depth of the liner hole 201' can be determined by controlling the size of the mold to match the welding of branch pipes of different specifications. However, the present invention does not limit this in any way. In other embodiments, the connecting part can also be a flanged part formed by punching and flanging the sheet base, or a stretched section formed by stretching; not only are the processing methods diverse and simple, but different flanged hole diameters and depths can also be achieved by selecting the size of the sheet material (such as wall thickness or area), which can also match the welding of branch pipes 30 of different specifications well. Specifically, the lowest point of the end face 2071' of the connecting part is set to the highest point of the busbar on the main pipe 10 ( Figure 32 The projection distance H of point G on the axis of branch pipe hole 101 satisfies: 0.15d ≤ H ≤ 2.2d, where d is the diameter of the branch pipe hole. This projection distance H provides guidance for the design of the dimensions of the connection portion 207' required for branch pipes of different specifications. While ensuring the welding depth of the branch pipe 30 meets the connection strength requirements, it minimizes the length of the connection portion 207' and reduces the volume of the outer liner plate 20' to further reduce its heat absorption effect on solder flowability. Furthermore, this setting effectively controls the cost of the outer liner plate 20'. Preferably, the projection distance H is set to satisfy: 0.18d ≤ H ≤ 2.15d. However, this invention does not impose any limitations on this.

[0120] Although the projection distance H on the connecting part 207' basically controls the welding depth of the branch pipe 30, only the straight section within the liner hole 201' on the outer liner plate can provide an effective welding depth for the branch pipe 30. In fact, besides the height of the connecting part 207', the radius R of the arc segment 208' between the plate base 206' and the inner wall of the connecting part 207' also affects the straight section of the liner hole 201' to some extent. Specifically, when the straight section of the liner hole 201' on the outer liner plate is determined, the larger the radius R of the arc segment 208', the higher the required height of the connecting part 207' will be. Therefore, this embodiment controls the radius R of the arc segment 208' to further shorten the height of the connecting part 207'; specifically, the radius R of the arc segment is set to ≤ 1.5 mm. Figure 33The diagram illustrates one possible processing method for the outer liner 20' provided by the present invention. Specifically, the arc segment 208' can be initially formed by warm extrusion, flanging, or stretching, at which point the radius R' of the arc segment 208' is approximately 1 mm. Subsequently, a shaping tool is inserted into the liner hole 201' to refine the arc segment 208', adjusting its radius to approximately 0.5 mm. However, the present invention does not impose any limitations on this process.

[0121] like Figure 32 As shown, in this embodiment, the end face 2071' of the connecting part is planar, and the lowest point of the end face 2071' of the connecting part can be any position on the end face 2071' of the connecting part. During brazing, the planar end face 2071' of the connecting part carries the solder, and the molten solder gradually penetrates into the liner hole 201' from this point, thus forming a brazing flow port at the end face 2071' of the connecting part. However, the present invention does not limit this in any way. In other embodiments, such as Figure 34A As shown, the end face 2071' of the connector can also gradually slope downwards towards the direction of the liner hole 201'. The inclined end face 2071' of the connector can better guide the molten solder into the liner hole 201' on the outer liner. At this time, the lowest point of the end face 2071' of the connector is the location of the liner hole 201' wall, and the projected distance H is shown in Figure 34A. Although Figure 34A In this embodiment, the end face 2071' of the connecting portion is an inclined plane; however, the present invention does not limit this in any way. In other embodiments, the end face of the connecting portion may also be a gradually inclined curved surface. Alternatively, in other embodiments, such as Figure 34B As shown, the liner hole 201' includes a first hole section 2011' and a second hole section 2012' that are coaxially connected in sequence along the insertion direction of the branch pipe 30. The inner diameter of the first hole section 2011' is larger than the inner diameter of the second hole section 2012'. A support step 2013' for placing solder is formed at the transition between the first hole section 2011' and the second hole section 2012'. The inner wall of the first hole section 2011' blocks the solder placed on the support step 2013', so that the solder can enter the second hole section 2012' completely, effectively avoiding solder overflow at the end face of the connection and thus preventing solder run-out.

[0122] To allow more solder to penetrate into the critical gaps 104 and 105 between the branch pipe hole 101 and the outer wall of the branch pipe 30, in this embodiment, the diameter d1 of the straight section of the liner hole 201' on the outer liner plate is set to satisfy: 0.95d ≤ d1 ≤ 1.2d, where d is the diameter of the branch pipe hole. Specifically, the diameter d of the branch pipe hole 101 is basically close to the outer diameter of the branch pipe 30. This setting achieves control of the assembly gap between the liner hole 201' of the outer liner plate 20' and the branch pipe 30, so as to better meet the capillary penetration performance of the solder during brazing. The straight section of the liner hole 201' on the outer liner plate refers to the area where the liner hole 201' provides an effective welding depth for the branch pipe 30 to form the gap 102; in Figure 31 and Figure 34A The straight section of the liner hole 201' is the area between the lowest point of the end face 2071' of the connecting part and the junction of the inner wall of the liner hole and the arc section 208'; while... Figure 34B In the middle, the straight section of the liner hole 201' is the area between the lowest point of the bearing step 2013' and the junction of the inner wall of the liner hole 201' and the arc section 208'.

[0123] As mentioned above, the fluid manifold assembly provided in this embodiment, while providing welding depth to the branch pipe 30 to ensure its connection strength, also significantly reduces the impact of the outer liner 20' on the flowability of the solder, thus improving brazing performance, due to the overall design of the outer liner 20', the wall thickness T1 of the plate base 206', the wall thickness T2 of the connecting part 207', and the radius R of the arc segment 208'. Furthermore, the outer liner 20' effectively solves the problem of solder flowing along the outer wall of the main pipe 10, further improving the welding quality. In this embodiment, a continuous self-fluxing weld 205' is formed between the plate base 206' and the outer wall of the main pipe 10, with the extension direction being approximately the same as the side wall edge of the plate base 206'. The continuous self-fluxing weld 205' not only achieves pre-fixation of the plate base 206' and the main pipe 10 before brazing, but also forms a blocking edge 202'. At the continuous self-fluxing weld 205', the capillary penetration gap between the plate-shaped base 206' and the outer wall of the main pipe 10 is blocked, thereby preventing the solder from penetrating into the gap located outside the continuous self-fluxing weld 205' to avoid weld run. Figure 31 As shown. Solder fills the gap 103 between the plate-shaped base 206' located inside the continuous self-fusion weld 205' and the outer wall of the main pipe 10 to form a brazed joint. Specifically, as... Figure 30 As shown, continuous self-fusion welds 205' are formed on the plate-shaped bases 206' on both sides of the connecting portion 207'. However, the present invention does not limit this in any way. In other embodiments, the continuous self-fusion welds may also be formed directly on the outer edge of the plate-shaped base (e.g., Figure 34A(As shown). Alternatively, a continuous self-fluxing weld can extend gradually along the end wall of the plate-shaped base to form a ring weld around the connection.

[0124] In fact, in the fluid distribution / manifold assembly provided in this embodiment, the self-fusion weld 205' not only pre-fixes the outer liner 202' before brazing, controls the brazing gap, and acts as a flow welding blocking edge, but also further enhances the connection strength and gas seal between the outer liner 202' and the outer wall of the main pipe 10 based on the brazing weld, so as to ensure the quality of the product after welding.

[0125] In other embodiments, such as Figure 35B As shown, multiple discontinuous self-fluxing welds 25' are formed between the sheet-like base 206' and the outer wall of the main pipe 10. These discontinuous self-fluxing welds 25' and the sidewall edge of the sheet-like base 206' together form a blocking edge 202'. At this time, at the sidewall edge of the sheet-like base 206', there is no longer a gap required for capillary penetration between the sheet-like base 206' and the outer wall of the main pipe 10 (i.e., the capillary penetration gap disappears), and the solder can no longer penetrate through the blocking edge 202', thus blocking the flow path. Alternatively, in other embodiments, multiple self-fluxing weld points can be formed between the sheet-like base and the outer wall of the main pipe, achieving pre-fixation of the sheet-like base and the main pipe before brazing; while the sidewall edge of the sheet-like base forms a blocking edge, and a brazing weld is formed between the sheet-like base and the outer wall of the main pipe. Alternatively, in other embodiments, the sheet-like base and the main tube are pre-fixed mechanically before brazing without the need for autofusion welding; the sidewall edge of the sheet-like base forms a blocking edge, and a brazing seam is formed between the sheet-like base and the outer wall of the main tube.

[0126] In this embodiment, continuous self-fusion weld, intermittent self-fusion weld, and self-fusion weld point refer to welds or weld points formed by self-fusion welding; self-fusion welding includes any one of laser welding, resistance welding, argon arc welding, or flash welding.

[0127] In this embodiment, as Figure 30 As shown, the outer edge of the sheet-like base 206' is a square arc-shaped piece, and two connecting portions 207' are formed on the sheet-like base 206'. However, the present invention does not limit this in any way. In other embodiments, the outer edge of the sheet-like base may also be racetrack-shaped (…). Figure 35A ), circle ( Figure 35B And other irregular structures. There is no limit to the number of connecting parts on each plate-shaped base; it can be one, three, or more than four.

[0128] In the fluid manifold assembly provided in this embodiment, the outer liner 20' is attached to the outer wall of the main pipe 10, and the liner hole 201' at the connecting part 206' on the outer liner 20' is coaxially connected to the branch pipe hole 101 on the main pipe. The liner hole 201 on the inner liner, the liner hole 201' on the outer liner, and the branch pipe hole 101 together provide the welding depth for the branch pipe. The split structure of the outer liner 20' and the main pipe 10 makes the depth of the liner hole 201' no longer limited by the migration amount, material properties, and pipe structure of the main pipe material. Its depth can be processed and shaped according to the insertion depth requirements of different branch pipes 30 to ensure the connection strength after the branch pipe is welded. On the outer liner 20', the sheet-like base structure greatly reduces the volume of the outer liner 20', thereby significantly reducing the impact of its heat absorption on the solder temperature during brazing, so that the solder can flow well into the critical gap located at the end of the penetration path. Furthermore, a blocking edge 202' is formed between the plate-shaped base and the wall of the main pipe 10. At the blocking edge 202', the capillary penetration effect formed by the gap between the plate-shaped base 206' and the outer wall of the main pipe 10 disappears, and the flow path of the solder along the outer wall of the main pipe 10 is blocked at the blocking edge. This allows the solder to flow only to the side where the branch hole 101 is located and gradually penetrate into the critical weld 104 and gap 105 between the inner wall of the branch hole 101 and the outer wall of the branch pipe 30, so as to ensure that the brazing strength, pressure resistance and air tightness of the branch pipe can meet the requirements well.

[0129] In summary, the welding and fixing method and tooling for the liner and main pipe of the fluid distribution / manifold assembly provided by this invention includes a receiving groove formed on the mandrel for placing the liner. During assembly, the inner liner is placed in the receiving groove of the mandrel. When the main pipe is fitted onto the mandrel, the inner liner will adhere to the inner wall of the main pipe along with the mandrel to achieve initial positioning. Subsequently, each positioning pin passes through the branch pipe hole and the liner hole one by one from the outside to the inside of the main pipe to coaxially position both. This coaxial positioning method from the outside to the inside greatly reduces the difficulty of aligning the positioning pins in the branch pipe hole and the liner hole, making assembly not only convenient but also efficient. Furthermore, a positioning pin avoidance recess is formed at the bottom of the receiving groove on the mandrel, providing avoidance space for the positioning pin in the insertion direction. After coaxially positioning the branch pipe hole and the liner hole, the clamping assembly cooperates with the mandrel to clamp and press the liner and the main pipe wall, controlling the assembly gap between the liner and the inner wall of the main pipe to meet the capillary penetration conditions in the subsequent brazing process. This ensures that after the branch pipe is brazed, the space between the liner and the main pipe wall is filled with uniform and sufficient solder. After clamping and bonding, the liner is fixed to the main pipe wall using a self-fusion welding method, thus fixing the liner to the main pipe before brazing the branch pipe to prevent displacement during the brazing process.

[0130] Although the present invention has been disclosed above by way of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of protection claimed in the claims.

Claims

1. A method for welding and fixing the upper liner and the main pipe of a fluid distribution / manifold assembly, characterized in that, The fluid manifold assembly includes a circular main pipe and a liner. The main pipe has at least three branch pipe holes on its wall for welding branch pipes, and the diameter of the branch pipe holes is less than 0.65 times the diameter of the main pipe. The liner is arc-shaped and has liner holes. The welding and fixing of the liner and the main pipe includes the following steps: The liner to be fixed is placed in the receiving groove on the mandrel, and the receiving groove is provided with positioning pin avoidance recesses corresponding to multiple branch pipe holes. Insert the main pipe onto the outside of the mandrel after the liner is placed, so that the arc surface of the liner fits against the inner wall of the main pipe and each liner hole is approximately opposite to the corresponding branch pipe hole. Each positioning pin passes through the corresponding branch pipe hole and liner hole from the outside of the main pipe inward and is inserted into the positioning pin avoidance recess on the mandrel to coaxially position the branch pipe hole and the corresponding liner hole. For the liner hole and branch pipe hole after the positioning pin is positioned, the clamping assembly is used to press the liner tightly against the inner wall of the main pipe; The inner wall of the main pipe is connected by self-fusion welding.

2. The welding and fixing method for the upper liner and main pipe of the fluid distribution / manifold assembly according to claim 1, characterized in that, When a lining plate also needs to be placed on the outer wall of the main pipe, the welding and fixing method further includes: After the main tube is inserted into the outside of the mandrel, the arc surface of the liner to be placed is fitted against the outer wall of the main tube, and each liner hole is roughly opposite to the corresponding branch pipe hole. When inserting the locating pins, each locating pin will pass through the liner hole, branch pipe hole and inner liner hole on the outer liner in sequence from the outside to the inside and be inserted into the locating pin clearance recess on the mandrel to locate the outer liner, main pipe and inner liner.

3. The method for welding and fixing the upper liner and main pipe of the fluid manifold assembly according to claim 1 or 2, characterized in that, The positioning pin has a shoulder that abuts against the outer wall of the main pipe or the outer liner. The clamping component applies force to each positioning pin, and the shoulder on the positioning pin clamps the liner and the pipe wall of the main pipe from the outside to the inside after positioning. Alternatively, the clamping assembly abuts against the outer wall of the main pipe or the outer liner, clamping the positioned liner and the main pipe wall from the outside in.

4. The welding and fixing method for the upper liner and main pipe of the fluid distribution / manifold assembly according to claim 3, characterized in that, The locating pin is pressed in a resilient manner by the clamping assembly; or, the outer wall of the main pipe or the outer liner is pressed in a resilient manner by the clamping assembly.

5. A welding fixture, characterized in that, The method described in any one of claims 1 to 4 is used to weld and fix the liner and main pipe on the fluid distribution / manifold assembly, wherein the welding and fixing fixture includes: Tooling brackets; The mandrel is set on the tooling bracket and one end of the mandrel is free during assembly so that the main pipe can be inserted. The mandrel has a receiving groove for placing the liner and the receiving groove is distributed with positioning pin avoidance recesses corresponding to multiple branch pipe holes. Multiple positioning pins, after the main pipe is fitted into the mandrel, each positioning pin passes through the corresponding branch pipe hole and liner hole one by one from the outside of the main pipe and is inserted into the positioning pin avoidance recess on the mandrel to position the liner and the main pipe. A clamping assembly is lifted and installed on the tooling bracket. The clamping assembly abuts against multiple positioning pins, the outer wall of the main pipe, or the outer liner to clamp the liner and the pipe wall of the main pipe after positioning.

6. The welding fixture according to claim 5, characterized in that, The positioning pin clearance recess on the mandrel is a plurality of clearance holes that correspond to the plurality of branch holes on the main pipe; Alternatively, the positioning pin clearance recess is one or more clearance grooves that correspond to multiple branch holes on the main pipe and extend along the mandrel axial direction.

7. The welding fixture according to claim 5, characterized in that, The size of the receiving groove on the mandrel matches the size of the liner, and there is a positioning adjustment gap between the side wall of the liner and the side wall of the receiving groove to adjust the coaxiality of the liner hole.

8. The welding fixture according to claim 5, characterized in that, A welding clearance groove is formed in the area covered by the liner plate on the mandrel. The welding clearance groove is located on both sides of the locating pin clearance recess and extends along the axial direction of the mandrel.

9. The welding fixture according to claim 5, characterized in that, The tooling bracket includes a base and two brackets located at both ends of the base. The connecting end of the mandrel is rotatably connected to the first bracket and rotates relative to the first bracket with the connection point as the fulcrum. The movable end of the mandrel can be detachably engaged with the second bracket. During assembly, the movable end of the mandrel is detached from the second bracket and is in a free state for the main pipe to be fitted in.

10. The welding fixture according to claim 5, characterized in that, Each positioning pin includes an insertion section, a shoulder, and a clamping section connected in sequence. The insertion section passes through the branch pipe hole and the liner hole and is inserted into the positioning pin clearance recess on the mandrel. The cross-sectional diameter of the shoulder is larger than that of the insertion section to abut against the outer wall of the main pipe or the outer liner. The clamping assembly includes multiple cylinders mounted on a tooling bracket and a clamping plate connected to the multiple cylinders. The clamping plate abuts against the clamping section of each positioning pin and presses each liner tightly against the wall of the main pipe through the shoulder.

11. The welding fixture according to claim 10, characterized in that, The clamping assembly also includes an elastic element disposed at the bottom of the clamping plate or on each locating pin clamping section. The elastic element deforms during the clamping stroke of the clamping assembly to compensate for the height difference between the end faces of the clamping plate and the clamping sections of each locating pin.

12. The welding fixture according to claim 5, characterized in that, The mandrel has multiple sets of positioning areas distributed along its circumference, each positioning area including a receiving groove and a positioning pin avoidance recess formed at the bottom of the receiving groove.

13. A fluid manifold assembly, characterized in that, It includes a circular main pipe, a liner, and at least three branch pipes. The main pipe has at least three branch pipe holes on its wall, and the diameter of the branch pipe holes is less than 0.65 times the diameter of the main pipe. The liner is arc-shaped and has liner holes, and the liner is assembled to the main pipe by the welding and fixing method according to any one of claims 1 to 4; Each branch pipe extends into and is brazed to the corresponding branch pipe hole and liner hole; The liner includes an outer liner disposed on the outer wall of the main pipe. The outer liner is located on the outer periphery of the lowest point of the busbar on the branch pipe hole and is attached to the outer wall of the main pipe. A blocking edge is formed between the outer liner and the outer wall of the main pipe. The blocking edge surrounds the outer periphery of the branch pipe hole in whole or in part to block the solder flow path along the outer wall of the main pipe. The side of the outer liner near the branch pipe hole forms a solder flow port pointing towards the inside of the branch pipe hole. Furthermore, on the main pipe section passing through the central axis of the branch pipe hole, a rectangular coordinate system is constructed with the highest point of the main pipe's upper generatrix as the origin, the central axis of the branch pipe hole as the positive direction of the Y-axis, and the radial direction of the main pipe as the X-axis; the ordinate of the initial flow point of the solder at the flow port falls in the positive direction of the Y-axis.

14. The fluid manifold assembly according to claim 13, characterized in that, The extension direction of the self-fusion weld formed between the outer liner and the outer wall of the main pipe is roughly the same as the edge of the side wall of the outer liner, and a blocking edge is formed at the self-fusion weld. Alternatively, the self-fusion weld and the sidewall edge of the outer liner can together form a blocking edge.

15. The fluid manifold assembly according to claim 14, characterized in that, The self-fusion weld is a continuous integral weld or includes multiple intermittent welds distributed at intervals.

16. The fluid manifold assembly according to claim 13, characterized in that, The gap between the hole wall of the liner plate and the outer wall of the branch pipe forms the material inlet, and the upper end of the hole wall of the liner plate is the initial flow point of the solder. Alternatively, a guide surface is formed on the outer liner surface near the liner hole to guide the solder into the branch pipe hole, and a flow port is formed at the guide surface, with the place where the solder initially flows being the furthest point on the guide surface from the branch pipe hole.

17. A fluid manifold assembly, characterized in that, It includes a circular main pipe, a liner, and at least three branch pipes. The main pipe has at least three branch pipe holes on its wall, and the diameter of the branch pipe holes is less than 0.65 times the diameter of the main pipe. The liner is arc-shaped and has liner holes, and the liner is assembled to the main pipe by the welding and fixing method according to any one of claims 1 to 4; Each branch pipe extends into and is brazed to the corresponding branch pipe hole and liner hole; The liner includes an outer liner disposed on the outer wall of the main pipe, and the outer liner has a liner-type structure, comprising a sheet-like base and a connecting portion formed in the middle region of the sheet-like base. The sheet-like base is welded to the outer wall of the main pipe. The connecting portion protrudes to the side away from the main pipe and has a liner hole coaxially connected to the branch pipe hole. A blocking edge is formed between the sheet-like base and the outer wall of the main pipe, and the blocking edge blocks the solder flow path along the outer wall of the main pipe. The wall thickness T1 of the base satisfies 0.085d≤T1≤0.65d, and the wall thickness T2 of the connecting part also satisfies 0.085d≤T2≤0.65d; and on the main pipe section passing through the central axis of the branch pipe hole, the distance L2 from the side wall edge of the plate base to the center of the liner hole satisfies: 0.8d≤L2≤3.5d, where d is the diameter of the branch pipe hole; each branch pipe is inserted into the liner hole on the outer liner base and the inserted end extends into the corresponding branch pipe hole on the main pipe, and the branch pipe is brazed to the liner hole and the branch pipe hole.

18. The fluid manifold assembly according to claim 17, characterized in that, The projection distance H from the lowest point of the end face of the connector to the highest point of the main busbar in the direction of the branch pipe hole axis satisfies: 0.15d≤H≤2.2d, where d is the diameter of the branch pipe hole; the end face of the connector is either flat or gradually slopes down towards the direction of the liner hole, and a brazing flow port is formed at the end face of the connector.

19. The fluid manifold assembly according to claim 17, characterized in that, The inner walls of the plate base and the liner hole are connected by a circular arc section with a radius R ≤ 1.5 mm. The diameter d1 of the liner hole at the straight section satisfies: 0.95d ≤ d1 ≤ 1.2d, where d is the diameter of the branch pipe hole.

20. The fluid manifold assembly according to claim 17, characterized in that, The connecting part is a flanged part formed by punching and flanging the sheet-like base; or, the connecting part and the sheet-like base are integrally formed by warm extrusion process.

21. The fluid manifold assembly according to claim 17, characterized in that, The liner hole includes a first hole section and a second hole section that are coaxially connected in sequence along the insertion direction of the branch pipe. The inner diameter of the first hole section is larger than the inner diameter of the second hole section. A bearing step for placing solder is formed at the transition between the first hole section and the second hole section.

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