A flute type tube hydroforming device

Abstract

This application discloses a flute-shaped tube liquid-filling forming device, which includes a mold, a left punch, a right punch, a side-push module, and a mold base plate. The mold has a flute-shaped tube forming cavity and a guide stop hole for the side-push punch. The left and right punches are respectively used to insert from both ends of the tube blank to seal the tube blank and apply axial thrust. The left punch has a pressure medium channel, and both the left and right punches have an adjustable extension structure that allows for axial adjustment of the sealing area length. The side-push module includes a side-push punch that mates with the guide stop hole of the side-push punch, used to provide lateral support force to the forming flute-shaped tube branches. This device, by adjusting the sealing area range step by step, forms each branch tube sequentially, eliminating material flow interference during the forming process of adjacent branches, improving the uniformity of branch tube wall thickness and the consistency of forming height, and achieving high-precision integral forming of multiple flute-shaped tube branches.

Description

Technical Field

[0001] This application belongs to the field of metal tube forming technology, specifically relating to a flute-shaped tube liquid filling forming device. Background Technology

[0002] A flute-shaped pipe (also known as a multi-branch pipe or branch pipe) is a multi-port pipe fitting with a cylindrical main pipe as the core and multiple branch pipes distributed along the circumference or axis of the main pipe, resembling a flute in shape. This type of pipe fitting is widely used in energy transmission pipelines, hydraulic transmission systems, chemical process pipelines, automotive fuel distribution pipelines, and aerospace fluid transmission systems. Due to the large number and dense distribution of branch pipes, flute-shaped pipes are difficult to form as a whole, placing high demands on the forming precision, wall thickness uniformity, and production efficiency of the manufacturing process.

[0003] Currently, the commonly used processes for manufacturing flute-shaped tubes mainly include the following.

[0004] The first method is the welding assembly forming process. This process involves preparing the main pipe section and each branch pipe section separately, and then connecting the branch pipes to the corresponding positions on the main pipe through welding. Although the welding assembly forming process is relatively simple to operate, the mechanical properties of the weld area are lower than those of the base material, and residual stress is easily generated in the heat-affected zone of the weld, leading to a decrease in the structural load-bearing capacity. For densely distributed multi-branch pipe structures, the welding heat input can also easily cause positional accuracy deviations between branches, often requiring subsequent alignment processes, increasing manufacturing costs and time.

[0005] Secondly, there are integral forming processes such as casting or forging. Casting uses a mold cavity to form the main structure with branch pipes in one step, while forging achieves the forming of multiple branch pipe sections through metal volume transfer. Both casting and forging processes can avoid performance discontinuities caused by welds. However, for thin-walled flute-shaped tubes, casting is prone to internal defects such as shrinkage porosity and gas bubbles, while forging faces problems such as complex mold structures and low material utilization. Furthermore, casting and forging blanks usually have machining allowances, which need to be removed by subsequent machining to ensure dimensional accuracy, resulting in a longer process chain.

[0006] Thirdly, there is the traditional hydraulic bulging forming method. This method involves filling the tube blank with a high-pressure liquid medium, causing the tube blank to bulge outwards to form branch pipes under the constraint of the mold cavity. Single-stage hydraulic bulging has certain advantages when dealing with tubes with a single branch pipe or a large branch pipe spacing. However, when used to form flute-shaped tubes with multiple densely distributed branch pipes, the material flow direction of adjacent branch pipe bulging areas interferes with each other, resulting in uneven wall thickness distribution between branch pipes. The height of some branch pipes is difficult to meet the design requirements, and even cracking failure may occur due to excessive thinning in some areas. To complete the forming of all branch pipes, multiple sets of molds are often required to carry out the process in stages, and the process efficiency is difficult to meet the needs of high-efficiency production.

[0007] In summary, existing welding assembly forming, casting or forging integral forming, and traditional hydraulic bulging processes in the manufacture of flute-shaped tubes have problems such as low weld strength and insufficient positional accuracy, low material utilization and difficulty in controlling the quality of the inner wall, as well as uneven wall thickness reduction and high risk of breakage caused by material flow interference during the forming of multiple tubes. Summary of the Invention

[0008] In order to address the problems of uneven wall thickness distribution, insufficient forming height, and local rupture caused by mutual interference of material flow in the bulging areas of adjacent branch pipes in the existing flute-shaped tube forming process, this application provides a liquid-filled forming device and method that can realize the integral forming of multiple branch pipes of the flute-shaped tube.

[0009] To achieve the above technical objectives, this application specifically employs the following technical solution: In one aspect of this application, a flute-shaped tube liquid filling and forming apparatus is provided, comprising: The mold has a flute-shaped tube forming cavity for placing tube blanks through a first direction. The mold has a plurality of side-push punch guide stop holes on its side wall in a second direction. The side-push punch guide stop holes are connected to the flute-shaped tube forming cavity. The first direction and the second direction are perpendicular to each other. Left punch and right punch are respectively used to insert into the tube blank from both ends to seal the tube blank and apply axial thrust to the tube blank. The left punch is provided with a pressure medium channel communicating with the inside of the tube blank. The opposite ends of the left punch and right punch are both provided with an adjustable extension structure that can be adjusted along the axial length. The side-push module includes a side-push punch that mates with the guide stop hole of the side-push punch, the side-push punch being used to provide lateral support force to the forming flute-shaped tube branch.

[0010] In one embodiment, the mold includes an upper mold and a lower mold, and the mating surfaces of the upper mold and the lower mold are respectively provided with a first groove along a first direction. The flute-shaped tube forming cavity is formed by the upper mold and the lower mold after they are closed. The mating surfaces of the upper mold and the lower mold are respectively provided with a second groove along a second direction, and after the mold is closed, a side push punch guide stop hole is formed.

[0011] In one embodiment, the side-push punch guide stop hole includes a circular hole section for forming a flute-shaped tube branch and a square hole section for guiding, and the transition between the circular hole section and the square hole section forms a stop surface that restricts the displacement of the side-push punch.

[0012] In one embodiment, the left punch includes a rear section, a middle section, and a front section. The rear section and the middle section are axially connected. The middle section is hollow. The front section is partially inserted into the middle section, and a first locking mechanism is provided between them for adjusting and fixing the extension length of the front section. The right punch includes a rear section, a middle section, and a front section. The rear section and the middle section are axially connected. The middle section is hollow. The front section is partially inserted into the middle section, and a second locking mechanism is provided between them for adjusting and fixing the extension length of the front section.

[0013] In one embodiment, the first locking mechanism includes a first locking groove formed on the middle section of the left punch, a plurality of first locking slots arranged axially in the first locking groove, and a first pin installed on the front section of the left punch. The first pin is used to cooperate with the first locking slots at different positions to fix the extension length of the front section of the left punch.

[0014] In one embodiment, the second locking mechanism includes a second locking groove formed on the middle section of the right punch, a plurality of second locking slots arranged axially within the second locking groove, and a second pin mounted on the front section of the right punch. The second pin is used to cooperate with the second locking slots at different positions to fix the extension length of the front section of the right punch.

[0015] In one embodiment, the front section of the left punch has a thin rod portion inserted into the middle section of the left punch and a cylindrical end head axially connected to the thin rod portion; the front section of the right punch has a thin rod portion inserted into the middle section of the right punch and a cylindrical end head axially connected to the thin rod portion; both the front sections of the left and right punches have annular grooves on their cylindrical end heads, and each annular groove is fitted with a rubber ring for forming a sealing fit with the inner wall of the tube blank.

[0016] In one embodiment, the side-push module further includes a limiting block for defining the extreme position of the side-push punch retraction and an elastic force application component for applying an elastic force toward the billet direction to the side-push punch.

[0017] In one embodiment, the elastic force application component includes a spring, a reaction block, and a clamping nut; the rear end of the side push punch passes through the reaction block and the limiting block in sequence; the spring is fitted on the side push punch and its two ends act on the stop portion of the side push punch and the reaction block, respectively; the clamping nut is threaded to the rear end of the side push punch and presses against the side of the reaction block away from the spring; the compression of the spring can be changed by adjusting the clamping nut.

[0018] In one embodiment, the front end of the side-push punch is provided with an arc surface that matches the outer diameter of the tube blank, and the middle part of the side-push punch is provided with a disc feature for contacting the limiting block to limit the backward stroke.

[0019] In one embodiment, the forming apparatus further includes a mold base plate, on which both the mold and the side-push module are mounted.

[0020] The beneficial effects of this application are as follows: 1. The branch pipes are formed step by step from the middle to both sides using the same set of molds. The forming process of adjacent branch pipes is independent of each other, which eliminates the interference of material flow when multiple branch pipes are expanded at the same time, effectively improves the uniformity of the branch pipe wall thickness distribution, and enhances the consistency of the branch pipe forming height.

[0021] Second, by using the adjustable structure of the front extension of the left and right punches, the sealing area of ​​the pressure medium can be precisely controlled during each forming process. Only the pipe section where the current forming branch is located is subjected to internal pressure, while the pipe sections outside the sealing area remain in their initial state. This avoids excessive frictional resistance between the pipe blank in the non-forming area and the mold cavity, which is conducive to the stable feeding of the pipe blank material into the forming area and reduces the risk of breakage at the top of the branch.

[0022] Third, in the side-pushing module, the side-pushing punch continuously contacts the outer wall of the tube blank under the action of the spring and provides back pressure support, which limits the deformation rate of the branch tube during the free expansion stage and prevents local excessive thinning from causing cracks. At the same time, the limiting block constrains the backward stroke of the side-pushing punch to ensure that the forming height of the branch tube is accurate and controllable.

[0023] Fourth, the device has a compact overall structure. The mold cavity and the guide stop hole of the side push punch are integrated into the same mold. There is no need to configure multiple sets of forming molds for different branch pipes. The processing cost is low, the process is simple, and the operation is easy to implement.

[0024] 5. By adjusting the spacing of the locking bayonet and the arrangement of the side push module, it can adapt to the forming requirements of flute-shaped tubes with different numbers of branch pipes and branch pipe spacing, and has good versatility. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the flute-shaped tube liquid filling and forming device according to an embodiment of this application; Figure 2 This is a front view of the flute-shaped tube liquid filling forming mold according to an embodiment of this application; Figure 3 This is a top view of the flute-shaped tube liquid filling forming mold according to an embodiment of this application; Figure 4 for Figure 2 Sectional view along line AA; Figure 5 for Figure 3 Sectional view along line BB; Figure 6 This is an exploded view of the left punch in an embodiment of this application; Figure 7 This is a schematic diagram of the mold structure in an embodiment of this application; In the diagram: 1. Mold, 101. Upper mold, 102. Lower mold, 103. Side-push punch guide stop hole; 2. Left punch, 201. Rear section of left punch, 202. Middle section of left punch, 203. Front section of left punch, 204. First pin, 205. Pressure medium channel, 206. First locking groove, 207. First locking slot; 3. Right punch, 301. Rear section of right punch, 302. Middle section of right punch, 303. Front section of right punch, 304. Second pin, 305. Second locking groove, 306. Second locking slot; 4. Side-push module, 401. Side-push punch, 402. Spring, 403. Compression nut, 404. Limiting block, 405. Support reaction block; 5. Mold base plate; 6. Rubber ring; 7. Tube blank. Detailed Implementation

[0026] The technical solution of this application will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are only some embodiments of this application, not all embodiments, and are only used to illustrate this application, and should not be regarded as limiting the scope of this application. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] To address the problem of uneven wall thickness reduction and cracking caused by mutual interference of material flow in the bulging zones of adjacent branches during the forming process of multi-branch flute tubes, this application proposes a liquid-filling forming approach that combines zoned sequential forming with variable control of the sealing area. The overall forming process of the multi-branch tube is divided into multiple independent bulging steps, performed sequentially from the middle branch to the side branches. Each step applies internal pressure only to a local area of ​​a single branch or a formed branch and its adjacent unformed branch. The sealing area is controlled by the extension length of the front sections of the left and right punches. By adjusting the insertion depth of the punch front section into the tube blank, combined with the axial pushing of the punch middle section end face to the tube blank end, the tube blank material in the non-forming area can be smoothly filled into the forming area, avoiding excessive frictional resistance caused by the material in the non-forming area conforming to the mold cavity due to internal pressure. Simultaneously, the side-push punch, under the action of an elastic element, always presses against the outer wall of the tube blank corresponding to the branch forming position, providing continuous back pressure during the bulging process to suppress material instability and thinning. The stroke of the side-push punch is constrained by a limiting block to ensure that the branch forming height meets the requirements.

[0028] In one specific implementation, refer to Figure 1-6As shown, a flute-shaped tube liquid filling forming device is provided. The device includes a mold 1, a left punch 2, a right punch 3, a side push module 4, and a mold base plate 5. In this application, the directional term "first direction" refers to the axial extension direction of the tube blank 7, and "second direction" refers to the lateral direction perpendicular to the first direction, corresponding to the extension direction of the flute-shaped tube branch.

[0029] The mold 1 has a flute-shaped forming cavity extending through it in the first direction. The flute-shaped forming cavity is used to accommodate the tube blank 7 to be formed, and the contour of the flute-shaped forming cavity is adapted to the shape of the final formed flute-shaped part. The mold 1 has a plurality of side pusher guide stop holes 103 on its side wall in the second direction, and each side pusher guide stop hole 103 is connected to the flute-shaped forming cavity.

[0030] In some embodiments, the side-push punch guide stop hole 103 includes a circular hole section located near the forming cavity of the flute-shaped tube and a square hole section connected to the circular hole section. The circular hole section constitutes the cavity part of the forming flute-shaped tube branch, and the square hole section plays a sliding guiding role for the side-push punch 401. The stepped surface at the junction of the circular hole section and the square hole section is used to limit the extreme pushing position of the side-push punch 401 in the direction of the tube blank 7.

[0031] The left punch 2 and right punch 3 are arranged opposite to each other in the device and are respectively used to insert into the tube blank 7 from both ends along a first direction. Both the left punch 2 and right punch 3 have sealing functions and the function of applying axial thrust. A pressure medium channel 205 is opened on the left punch 2, which runs through the axial direction of the left punch 2. During the forming process, the pressure medium channel 205 introduces the liquid medium provided by the external high pressure source into the inner cavity of the tube blank 7. An adjustable extension structure is provided at the opposite end of the left punch 2 and right punch 3. The adjustable extension structure can adjust the distance of the front end of the left punch 2 and the front end of the right punch 3 extending out of their respective middle end faces along the axial direction, thereby changing the depth of the front end of the left punch 2 and the front end of the right punch 3 inserted into the tube blank 7, and thus controlling the length of the sealing area inside the tube blank 7 under the action of the pressure medium.

[0032] The side-pushing module 4 includes multiple side-pushing punches 401, the number of which is equal to the number of branch pipes to be formed in the flute-shaped tube. In some embodiments, the front section of the side-pushing punch 401 is a cylindrical section with a diameter consistent with the outer diameter of the flute-shaped tube branch pipe. The end of the cylindrical section is machined with an arc feature, the curvature of which matches the curvature of the outer surface of the tube blank 7. When the front section of the side-pushing punch 401 is inserted into the side-pushing punch guide stop hole 103, the end of the cylindrical section of the side-pushing punch 401 can fit against the outer wall of the tube blank 7 placed in the flute-shaped tube forming cavity. A square column section is adjacent to the rear of the cylindrical section of the side-pushing punch 401. The square column section is used to slide and engage with the square hole section of the side-pushing punch guide stop hole 103, restricting the side-pushing punch 401 from rotating circumferentially. A disc feature is provided behind the square column section, the outer diameter of which is larger than the size of the square column section to form a limiting step. Behind the disc feature is the rod feature, and the end of the rod feature is machined with external threads.

[0033] The mold base plate 5 is a rectangular plate. The mold 1 and the side push module 4 are installed on the upper surface of the mold base plate 5 by bolts or other conventional fixing methods. The mold base plate 5 itself is installed on the working platform of the liquid filling press, thereby stabilizing the entire device in the press.

[0034] The device in this embodiment, through the adjustable extension structure on the left punch 2 and right punch 3, can control the effective range of the pressure medium inside the tube blank 7 in stages. First, the middle branch pipe is filled and formed, then the sealing range is expanded sequentially to form adjacent branch pipes and the branch pipes on both sides. This avoids material flow interference when multiple branch pipes are formed simultaneously, significantly improving the uniformity of wall thickness distribution and the consistency of branch pipe forming height. The side-push module 4 can achieve adaptive application and precise limiting of the support reaction force, preventing excessive thinning or cracking of the top of the branch pipe. The overall device has a compact structure, is easy to operate, and has good process adaptability to flute-shaped tube products with different numbers and distributions of branch pipes.

[0035] In some embodiments, the mold 1 is composed of an upper mold 101 and a lower mold 102. Each of the upper mold 101 and the lower mold 102 has a mating surface, with the mating surface of the upper mold 101 and the mating surface of the lower mold 102 facing each other. Along a first direction, the mating surface of the upper mold 101 has a first groove, and the mating surface of the lower mold 102 also has a first groove. When the upper mold 101 and the lower mold 102 are in the closed state, the first groove of the upper mold 101 and the first groove of the lower mold 102 engage, jointly defining the flute-shaped tube forming cavity. The flute-shaped tube forming cavity extends through the mold 1 along the first direction, and the cross-sectional profile of the flute-shaped tube forming cavity is consistent with the outer peripheral profile of the main tube of the flute-shaped tube to be formed.

[0036] Along the second direction, the upper mold 101 has a second groove on its closing surface, and the lower mold 102 also has a second groove on its closing surface. The second direction is perpendicular to the first direction. When the upper mold 101 and the lower mold 102 are in the closed state, the second groove of the upper mold 101 and the second groove of the lower mold 102 engage, jointly defining the side push punch guide stop hole 103. The side push punch guide stop hole 103 includes a circular hole section near the flute-shaped tube forming cavity and a square hole section connected to the circular hole section. The axis of the circular hole section extends along the second direction, and the inner diameter of the circular hole section corresponds to the outer diameter of the flute-shaped tube branch. The cross-section of the square hole section is rectangular, and the square hole section is used for sliding engagement with the square column section of the side push punch 401.

[0037] Preferably, the parting surfaces of the upper mold 101 and the lower mold 102 are coplanar with the central axis plane of the flute-shaped tube forming cavity. Since the flute-shaped tube forming cavity extends along the first direction and its cross-section is symmetrical about the central axis plane, the parting surface passing through the central axis plane allows the formed flute-shaped tube part to be directly removed in the radial direction when the upper mold 101 and the lower mold 102 are opened, eliminating the need for an additional complex demolding mechanism. This simplifies the device structure and improves part removal efficiency.

[0038] In some embodiments, the left punch 2 includes a rear section 201, a middle section 202, and a front section 203. The rear section 201 is axially fixedly connected to the middle section 202, and a threaded connection is provided at the end of the rear section 201 opposite to the middle section 202 for connection with the punch rod of the left horizontal cylinder of the filling press. The middle section 202 is a hollow cylinder with a central hole extending axially inside, the diameter of which matches the diameter of the thin rod portion in the front section 203. The front section 203 includes a thin rod portion and a cylindrical end head connected sequentially axially, the outer diameter of which is smaller than the outer diameter of the cylindrical end head. The thin rod portion of the left punch front section 203 slides into the central hole of the left punch middle section 202 from one end, allowing the axial extension length of the left punch front section 203 relative to the left punch middle section 202 to be adjusted. A pressure medium channel 205 is axially extended through the center of the left punch front section 203, passing through the thin rod portion and the cylindrical end head, for conveying the liquid medium introduced by the external high-pressure source to the inner cavity of the tube blank 7.

[0039] The left punch 2 is equipped with a first locking mechanism, which is used to fix the relative position of the front section 203 and the middle section 202 of the left punch after adjusting the extension length of the front section 203. The first locking mechanism includes a first locking groove 206 formed on the side wall of the middle section 202 of the left punch, a plurality of first locking slots 207 arranged at intervals along the axial direction of the middle section 202 of the left punch in the first locking groove 206, and a first pin 204 fixedly installed on the thin rod part of the front section 203 of the left punch. The first locking groove 206 is a racetrack-shaped through hole extending along the axial direction, and two first locking grooves 206 are symmetrically arranged around the circumference of the middle section 202 of the left punch. Each first locking slot 207 is a semi-circular or arc-shaped notch protruding outward from the long edge of the first locking groove 206. The plurality of first locking slots 207 are arranged at equal intervals along the axial direction, and the center distance between adjacent first locking slots 207 is equal to the distance between the target flute-shaped tube branches. The first pin 204 penetrates radially through the thin rod portion of the front section 203 of the left punch and extends out at both ends. The protruding portion of the first pin 204 is embedded in the first locking groove 206, and the first pin 204 can slide axially along the first locking groove 206. When the first pin 204 slides into a certain first locking slot 207, the first pin 204 is blocked by the edge of the first locking slot 207 and cannot move axially, thereby locking the extension length of the front section 203 of the left punch relative to the middle section 202 of the left punch. By switching the first pin 204 to different axial positions of the first locking slots 207, the extension length of the front section 203 of the left punch can be adjusted in stages.

[0040] The right punch 3 includes a rear section 301, a middle section 302, and a front section 303. The rear section 301 is axially fixedly connected to the middle section 302. A threaded connection is provided at the end of the rear section 301 facing away from the middle section 302, for connecting to the punch rod of the horizontal cylinder on the right side of the filling press. The middle section 302 is a hollow cylinder with a central hole extending axially inside. The diameter of the central hole matches the diameter of the thin rod portion in the front section 303. The front section 303 includes a thin rod portion and a cylindrical end head connected sequentially along the axial direction. The thin rod portion of the front section 303 slides into the central hole of the middle section 302 from one end, allowing adjustment of the axial extension length of the front section 303 relative to the middle section 302. No pressure medium passage is provided on the right punch 3.

[0041] The right punch 3 is equipped with a second locking mechanism, which is used to fix the relative position of the front section 303 and the middle section 302 of the right punch after adjusting the extension length of the front section 303. The second locking mechanism includes a second locking groove 305 opened on the side wall of the middle section 302 of the right punch, a plurality of second locking slots 306 arranged at intervals along the axial direction of the middle section 302 of the right punch in the second locking groove 305, and a second pin 304 fixedly installed on the thin rod part of the front section 303 of the right punch. The second locking groove 305 is a racetrack-shaped through hole extending along the axial direction, and two second locking grooves 305 are symmetrically arranged around the circumference of the middle section 302 of the right punch. Each second locking slot 306 is a semi-circular or arc-shaped notch protruding outward from the long edge of the second locking groove 305. The plurality of second locking slots 306 are arranged at equal intervals along the axial direction, and the center distance between adjacent second locking slots 306 is equal to the distance between the target flute-shaped tube branches. The second pin 304 penetrates radially through the thin rod portion of the front section 303 of the right punch and extends out at both ends. The protruding portion of the second pin 304 is embedded in the second locking groove 305, and the second pin 304 can slide axially along the second locking groove 305. When the second pin 304 slides into a certain second locking slot 306, the second pin 304 is blocked by the edge of the second locking slot 306 and cannot move axially, thereby locking the extension length of the front section 303 of the right punch relative to the middle section 302 of the right punch. By switching the second pin 304 to different axial positions of the second locking slots 306, the extension length of the front section 303 of the right punch can be adjusted in stages.

[0042] During the forming process, the operator can adjust the engagement positions of the first pin 204 with different first locking slots 207, and the engagement positions of the second pin 304 with different second locking slots 306, thereby changing the insertion depth of the left punch front section 203 and the right punch front section 303 into the tube blank 7. When the left punch front section 203 and the right punch front section 303 are inserted into the tube blank 7, the cylindrical ends form a radial seal with the inner wall of the tube blank 7. The end faces of the left punch middle section 202 and the right punch middle section 302 abut against the two end faces of the tube blank 7, providing axial thrust. The change in the insertion depth of the left punch front section 203 and the right punch front section 303 directly determines the length of the sealing area inside the tube blank 7 subjected to the pressure medium, thus enabling the sequential forming of the intermediate branch pipe, adjacent branch pipes, and side branch pipes in different steps, achieving precise step-by-step forming of each branch pipe.

[0043] Preferably, an annular groove is formed on the outer circumferential surface of the cylindrical end of the left punch front section 203. A rubber ring 6 is embedded in the annular groove, and the rubber ring 6 is fitted against the groove wall. When the left punch front section 203 is inserted into the inner cavity of the tube blank 7, the outer circumferential surface of the rubber ring 6 contacts the inner wall of the tube blank 7 and generates elastic compression, thereby establishing a radial seal between the left punch front section 203 and the inner wall of the tube blank 7. Similarly, an annular groove is also formed on the outer circumferential surface of the cylindrical end of the right punch front section 303, and the rubber ring 6 is embedded in the annular groove of the right punch front section 303. When the right punch front section 303 is inserted into the inner cavity of the tube blank 7, the outer circumferential surface of the rubber ring 6 forms a radial sealing fit with the inner wall of the tube blank 7.

[0044] In some embodiments, the side-push module 4 further includes a limiting block 404 and an elastic force-applying component. The limiting block 404 is used to limit the extreme position of the side-push punch 401 in the direction away from the mold 1 during the branch tube forming process. The elastic force-applying component is used to continuously apply an elastic thrust toward the tube blank 7 to the side-push punch 401, so that the front end of the side-push punch 401 always fits against the outer wall of the tube blank 7 and provides lateral support force during the branch tube expansion process.

[0045] The limiting block 404 is formed by two rectangular plates joined together vertically. After assembly, the limiting block 404 forms multiple circular holes, the number of which is equal to the number of flute-shaped tube branches. The axial direction of the circular holes coincides with the axial direction of the guide stop hole 103 of the side push punch. The limiting block 404 is fixedly connected to the upper surface of the mold base plate 5 by bolts, and the limiting block 404 is located on the outer side of the mold 1 along the second direction.

[0046] The elastic force application component includes a spring 402, a reaction block 405, and a clamping nut 403. The reaction block 405 is a rectangular plate with multiple circular holes, the number of which is equal to the number of flute-shaped tube branches. The reaction block 405 is fixedly connected to the upper surface of the mold base plate 5 by bolts. The reaction block 405 and the limiting block 404 are arranged at intervals along the second direction, with the reaction block 405 located on the side of the limiting block 404 away from the mold 1.

[0047] The side-push punch 401 has a disc feature in its middle part, which protrudes radially outward along the side-push punch 401, and the rear end face of the disc feature forms a stop. The rear end of the side-push punch 401 is a round rod section, and the end of the round rod section is machined with external threads.

[0048] The round rod segment of the side-push punch 401 passes sequentially through the round holes on the support reaction block 405 and the limiting block 404, with the front end of the side-push punch 401 extending into the side-push punch guide stop hole 103. A spring 402 is fitted onto the round rod segment of the side-push punch 401, positioned between the limiting block 404 and the support reaction block 405. The first end of the spring 402 abuts against the rear end face of the disc-shaped feature of the side-push punch 401, and the second end of the spring 402 abuts against the side of the support reaction block 405 facing the limiting block 404. A clamping nut 403 is threaded onto the external thread at the end of the round rod segment of the side-push punch 401, with one end face of the clamping nut 403 pressing against the side of the support reaction block 405 away from the spring 402.

[0049] The axial position of the clamping nut 403 on the circular rod section of the side-push punch 401 can be changed by rotating the clamping nut 403. When the clamping nut 403 is rotated closer to the support reaction block 405, the clamping nut 403 pushes the support reaction block 405, forcing the spring 402 to compress. The compression of the spring 402 increases, and the elastic thrust exerted by the spring 402 on the rear end face of the disc feature of the side-push punch 401 increases accordingly. When the clamping nut 403 is rotated away from the support reaction block 405, the compression of the spring 402 decreases, and the elastic thrust exerted by the spring 402 on the side-push punch 401 decreases accordingly. After adjusting the clamping nut 403 to an appropriate position, the preload of the spring 402 can be set to the lateral support reaction force value required to adapt to different billet materials, wall thicknesses, and internal pressure process parameters.

[0050] During the branch pipe liquid filling and forming process, the high-pressure liquid medium inside the tube blank 7 forces the material in the branch pipe section to flow outward, and the side push punch 401 retracts in the second direction under the force of the material. During the retraction process, the rear end face of the disc feature of the side push punch 401 compresses the spring 402, and the reaction force generated by the spring 402 is transmitted to the branch pipe forming area through the side push punch 401, forming a lateral support reaction force to prevent the top of the branch pipe from cracking or thinning due to excessive material flow. When the side push punch 401 retracts to the rear end face of the disc feature and contacts the limiting block 404, the limiting block 404 prevents the side push punch 401 from continuing to retract, and the branch pipe forming height reaches the preset maximum value. At this time, even if the internal pressure of the tube blank 7 continues to increase, the position of the side push punch 401 remains fixed, and the final forming height of the branch pipe is precisely controlled. After forming is completed, the internal pressure is released, and the spring 402 pushes the side push punch 401 back to the initial position for the next forming cycle.

[0051] Example The target part is a flute-shaped tube. The flute-shaped tube is made of 1Cr18Ni10Ti. The outer diameter of the main tube is 20mm, the outer diameter of the branch tube is 10mm, the wall thickness is 1.0mm, there are 5 branch tubes, the spacing between adjacent branch tubes is equal and is 40mm, and the total length of the flute-shaped tube is 200mm.

[0052] Reference Figure 1-6 As shown, the specific implementation is carried out through the following steps.

[0053] Step 1: Shaping preparation.

[0054] The device is manufactured according to the structure of the flute-shaped tube filling and forming device. The outer diameters of the left punch middle section 202 and the right punch middle section 302 are both 20mm. The outer diameters of the left punch front section 203 with the annular groove and the right punch front section 303 with the annular groove are both 17.8mm. The distance between adjacent first locking slots 207 on the left punch 2 and adjacent second locking slots 306 on the right punch 3 are both 40mm. The entire device is mounted on the working platform of the filling press via the mold base plate 5. The left punch 2 is connected to the punch rod of the left horizontal cylinder of the filling press, and the right punch 3 is connected to the punch rod of the right horizontal cylinder of the filling press. The high-pressure source of the filling press is connected to the pressure medium channel 205 of the left punch 2. A pre-determined length of tube section is cut according to the process requirements of the target part to form a tube blank 7. By adjusting the position of the first pin 204 of the left punch 2 in the first locking slot 207 and the position of the second pin 304 of the right punch 3 in the corresponding second locking slot 306, the extension amount of the front section 203 of the left punch and the extension amount of the front section 303 of the right punch are both at their maximum values.

[0055] Step 2: Forming the intermediate branch pipe.

[0056] Open the upper mold 101, place the tube blank 7 in the first groove of the lower mold 102, and close the upper mold 101 and the lower mold 102. The front section 203 of the left punch and the front section 303 of the right punch are inserted into the inner cavity of the tube blank 7 from both ends. The rubber ring 6 in the annular groove of the front section 203 of the left punch and the rubber ring 6 in the annular groove of the front section 303 of the right punch form a radial seal with the inner wall of the tube blank 7. The sealing area corresponds to the axial position of the middle branch of the flute-shaped tube. The high pressure source of the liquid filling press injects pressure medium into the inner cavity of the tube blank 7 through the pressure medium channel 205. Under the combined action of the axial thrust of the left punch 2, the axial thrust of the right punch 3, and the internal pressure of the pressure medium, the material of the tube blank 7 located in the sealing area flows outward to form the middle branch. During the forming process, the arc surface of the front end of the side push punch 401 always fits against the outer surface of the tube blank 7. Under the action of the spring 402, the side push punch 401 applies a lateral support reaction force to the direction of the tube blank 7. As the height of the intermediate branch pipe increases, the side-push punch 401 gradually retracts along the side-push punch guide stop hole 103 until the disc feature in the middle of the side-push punch 401 touches the limit stop block 404, at which point the side-push punch 401 stops retracting, and the forming height of the intermediate branch pipe reaches the predetermined value. Subsequently, the pressure of the pressure medium is increased to shape the intermediate branch pipe. After the pressure medium pressure is released, the left punch 2 and right punch 3 retract.

[0057] Step 3: Forming of the secondary intermediate branch pipe.

[0058] After the left punch 2 and right punch 3 retract, adjust the position of the first pin 204 of the left punch 2 in the first locking slot 207 and the position of the second pin 304 of the right punch 3 in the corresponding second locking slot 306. Then, insert the front sections 203 of the left punch and 303 of the right punch back into the inner cavity of the tube blank 7 from both ends. At this point, the sealing area corresponds to the axial position of the adjacent secondary intermediate branch pipe of the intermediate branch pipe. Under the combined action of the axial thrust of the left punch 2, the axial thrust of the right punch 3, and the internal pressure of the pressure medium, the secondary intermediate branch pipe is formed. The side-push punch 401 provides lateral support reaction force, and the forming process is the same as the branch pipe forming process in step two.

[0059] Step 4: Form the branch pipes on both sides.

[0060] Following the method in step three, adjust the front section 203 of the left punch and the front section 303 of the right punch again, so that the sealing area expands in sequence to cover the axial position of the outer branch pipe that has been formed, and form the remaining branch pipes in sequence until all five branch pipes are formed.

[0061] Step 5: Finish forming and remove the part.

[0062] After all the branch pipes are formed, the pressure medium inside the tube blank 7 is removed and discharged. The left punch 2 and right punch 3 are retracted, the upper mold 101 is opened, and the formed flute-shaped tube part is taken out from the flute-shaped tube forming cavity of the lower mold 102.

[0063] Although the embodiments of this application have been described above in conjunction with the accompanying drawings, this application is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, not restrictive. Those skilled in the art can make many other forms based on the guidance of this specification and without departing from the scope of protection of the claims of this application, and these are all within the scope of protection of this application.

Claims

1. A flute-shaped tube liquid filling and forming device, characterized in that, include: The mold has a flute-shaped tube forming cavity for placing tube blanks through a first direction. The mold has a plurality of side-push punch guide stop holes on its side wall in a second direction. The side-push punch guide stop holes are connected to the flute-shaped tube forming cavity. The first direction and the second direction are perpendicular to each other. Left punch and right punch are respectively used to insert into the tube blank from both ends to seal the tube blank and apply axial thrust to the tube blank. The left punch is provided with a pressure medium channel communicating with the inside of the tube blank. The opposite ends of the left punch and right punch are both provided with an adjustable extension structure that can be adjusted along the axial length. The side-push module includes a side-push punch that mates with the guide stop hole of the side-push punch, the side-push punch being used to provide lateral support force to the forming flute-shaped tube branch.

2. The flute-shaped tube liquid filling and forming device according to claim 1, characterized in that, The mold includes an upper mold and a lower mold. The mating surfaces of the upper mold and the lower mold are respectively provided with a first groove along a first direction. The flute-shaped tube forming cavity is formed by the upper mold and the lower mold after they are closed. The mating surfaces of the upper mold and the lower mold are respectively provided with a second groove along a second direction. After the mold is closed, a side push punch guide stop hole is formed.

3. The flute-shaped tube liquid filling and forming device according to claim 1, characterized in that, The side-push punch guide stop hole includes a round hole section for forming the flute-shaped tube branch and a square hole section for guiding. The transition between the round hole section and the square hole section forms a stop surface that restricts the displacement of the side-push punch.

4. The flute-shaped tube liquid filling and forming device according to claim 1, characterized in that, The left punch includes a rear section, a middle section, and a front section. The rear and middle sections are axially connected. The middle section is hollow. The front section is inserted into the middle section, and a first locking mechanism is provided between them to adjust and fix the extension length of the front section. The right punch includes a rear section, a middle section, and a front section. The rear and middle sections are axially connected. The middle section is hollow. The front section is inserted into the middle section, and a second locking mechanism is provided between them to adjust and fix the extension length of the front section.

5. The flute-shaped tube liquid filling and forming device according to claim 4, characterized in that, The first locking mechanism includes a first locking groove formed on the middle section of the left punch, a plurality of first locking slots arranged axially in the first locking groove, and a first pin installed on the front section of the left punch. The first pin is used to cooperate with the first locking slots at different positions to fix the extension length of the front section of the left punch.

6. The flute-shaped tube liquid filling and forming device according to claim 4, characterized in that, The second locking mechanism includes a second locking groove formed on the middle section of the right punch, a plurality of second locking slots arranged axially in the second locking groove, and a second pin installed on the front section of the right punch. The second pin is used to cooperate with the second locking slots at different positions to fix the extension length of the front section of the right punch.

7. The flute-shaped tube liquid filling and forming device according to claim 4, characterized in that, The front section of the left punch has a thin rod portion inserted into the middle section of the left punch and a cylindrical end head axially connected to the thin rod portion. The front section of the right punch has a thin rod portion inserted into the middle section of the right punch and a cylindrical end head axially connected to the thin rod portion. Both the front sections of the left and right punches have annular grooves on their cylindrical end heads, and each annular groove is fitted with a rubber ring for forming a sealing fit with the inner wall of the tube blank.

8. The flute-shaped tube liquid filling and forming device according to claim 1, characterized in that, The side-push module also includes a limiting block for limiting the extreme position of the side-push punch's retraction and an elastic force application component for applying an elastic force toward the billet direction to the side-push punch. The elastic force application component includes a spring, a support reaction block, and a clamping nut; the rear end of the side push punch passes through the support reaction block and the limiting block in sequence; the spring is fitted on the side push punch and its two ends act on the stop part on the side push punch and the support reaction block, respectively; the clamping nut is threaded to the rear end of the side push punch and presses against the side of the support reaction block away from the spring; the compression of the spring can be changed by adjusting the clamping nut.

9. The flute-shaped tube liquid filling and forming device according to claim 8, characterized in that, The front end of the side-push punch is provided with an arc surface that matches the outer diameter of the tube blank, and the middle part of the side-push punch is provided with a disc feature for contacting the limiting block to limit the backward stroke.

10. The flute-shaped tube liquid filling and forming device according to claim 1, characterized in that, The forming device also includes a mold base plate, and both the mold and the side push module are mounted on the mold base plate.

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