Asymmetric Y-shaped three-way half-tube rubber bag step-by-step forming device and method

Abstract

The invention discloses a step-by-step forming device and method for a rubber bag of an asymmetric Y-shaped three-way half pipe, and the method comprises the following steps: firstly, determining a plate material of the three-way half pipe, placing the plate material on a die workbench, arranging the rubber bag above the plate material, and carrying out allowance adding forming and pressure maintaining on the lower part of the plate material by utilizing a three-way half pipe convex die; then, the formed part is detected; if the film pasting degree of the acute angle area between the main pipe and the branch pipe does not meet the requirement, stamping and shaping are conducted; at the moment, the rubber bag is replaced with a three-way half-pipe female die, and meanwhile the three-way half-pipe male die and the three-way half-pipe female die are used for conducting stamping treatment on the part; and finally, post-processing the stamped and shaped part to obtain an asymmetric Y-shaped three-way half-pipe finished product. According to the method, the defects of the three-way half-pipe part formed through deep drawing in the prior art can be effectively overcome, and meanwhile the risks of local thinning and cracking in rubber bag female die forming are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-part processing method, in particular to a non-symmetrical Y-shaped three-way half pipe rubber bag step forming method, and is especially suitable for forming of difficult deformation materials such as stainless steel and aluminum alloy. BACKGROUND

[0002] Three-way pipe fittings are important components of fluid transmission systems in the field of aerospace, and have been widely used in fuel systems, hydraulic transmission systems and oxygen supply systems. Traditional three-way pipe fitting forming is divided into several parts according to the spatial shape of the three-way pipe, and then the parts are welded after forming, which has poor mechanical properties, surface quality and overall precision of the pipe fitting, low manufacturing efficiency, and is difficult to meet the increasing demand for manufacturing of aero-parts; therefore, currently, the aviation manufacturing enterprises often use whole pipe forming and half pipe forming. Whole pipe forming mainly uses internal high pressure forming process, which is generally suitable for forming relatively regular shape and low branch pipe three-way pipe fittings, but the loading path matching of internal high pressure forming process is difficult, the wall thickness of the formed three-way pipe fitting is not uniform, and the overall die adaptability is poor, which affects the efficiency due to frequent replacement; half pipe forming is to avoid circumferential welds and reduce the number of forming according to the spatial shape of the three-way pipe, and three-way half pipe parts are formed in separate parts; traditional three-way half pipe forming mostly uses drop pressing or stamping forming process, which has obvious shortcomings: serious local thinning, poor surface quality, low efficiency, low yield, etc.

[0003] Compared with the traditional stamping forming process, rubber bag forming can provide uniform pressure step by step. When forming a component with a bending edge or axial symmetry, since the rubber bag can fit the surface of the component, the pressure can act uniformly on the sheet metal, making the material deformation more uniform, reducing springback and avoiding defects such as wrinkling and cracking. Rubber bag forming process is divided into two forming methods of punch forming and die forming. When facing complex shape and non-axially symmetric thin-walled components, if the general rubber bag die forming method is adopted, due to its irregular structure, stress concentration will occur at the fillet of some areas, resulting in local thinning, and when the pressure is too large, even rupture will occur.

[0004] Patent application No. 201310557349.0, entitled "A T-shaped tee pipe drawing forming method" is only applicable to materials with high strength and ductility, and adopts a process supplement ear piece on the unfolded blank to realize a similar bulging drawing method to eliminate the middle fold. Forming a large-diameter tee pipe part of aluminum alloy sheet according to the method is prone to cracking, the method has very strict requirements for the shape of the blank and the structure of the mold, and is only applicable to regular-shaped plate steel tee pipes, and has poor versatility. Patent application No. 201410047901.6, entitled "Forming method and composite stamping die for tee half pipe part", provides a forming method and composite stamping die suitable for aluminum alloy tee half pipe parts with poor ductility, low strength and thin thickness, but the method needs to make auxiliary devices such as upper and lower dies and pressing blocks, which is too complex, only suitable for relatively regular-shaped and similar-shaped tee half pipe stamping forming, and has great limitations due to the shape of the tee half pipe.

[0005] The tee half pipe is formed by a rubber bladder, and the pressure is uniformly transmitted through a flexible medium (liquid-filled rubber), which can avoid scratching of the plate by a rigid die, especially for materials such as stainless steel and aluminum alloy, and the surface of the formed part is smooth, which significantly improves the fatigue life. The flexible rubber bladder can flow and fill the die surface, and the fit of asymmetric or special-shaped structures (such as branch pipes and variable curvature areas) is better than that of rigid dies. For example, the branch transition area of Y-shaped tee can be naturally formed by rubber flow, reducing stress concentration; the process and cost can be reduced, and for simple tee structure (such as T-shaped), 1-2 times of forming can be realized, reducing manual correction, and multiple rigid dies are not required, which is especially suitable for small batch production; flexible forming reduces the risk of wrinkling and reduces the scrap rate. Foreign enterprises can control the manual finishing amount to a very low level through process optimization; however, in the process of forming complex tee half pipes, for example, the branch angle of the inclined Y-shaped structure is asymmetric (such as 50° transition), the difference in material flow between the left and right sides easily causes material accumulation (wrinkling) or excessive thinning (cracking), and the wall thickness after forming is not uniform. SUMMARY

[0006] The purpose of the present application is to provide an asymmetric Y-shaped tee half pipe rubber bladder step forming device and method to overcome the defects in the prior art of drawing forming tee half pipe parts, while reducing the risk of local thinning and cracking in rubber bladder die forming.

[0007] In order to achieve the above-mentioned task, the present application adopts the following technical solutions: The application discloses a non-symmetrical Y-shaped three-way half pipe rubber bag step forming device, which comprises a mold workbench, a forming cavity is arranged in the mold workbench in the longitudinal direction, a circle of positioning grooves is arranged on the top of the forming cavity in the circumferential direction and is used for placing a forming plate of the three-way half pipe, a three-way half pipe male die is arranged in the forming cavity, a driving device capable of driving the three-way half pipe male die to move in the longitudinal direction is arranged below the three-way half pipe male die, a rubber bag is arranged above the mold workbench, the rubber bag is installed on a pressurizing device, the pressurizing device can provide a preset compacting force for the rubber bag, and the rubber bag can be dismounted and replaced by a three-way half pipe female die.

[0008] Further, the three-way half pipe male die and the three-way half pipe female die are both rigid dies, and shapes of the three-way half pipe male die and the three-way half pipe female die are matched with the non-symmetrical three-way half pipe to be processed; and the acute angle region and the obtuse angle region of the three-way half pipe male die are chamfered.

[0009] The application further discloses a non-symmetrical Y-shaped three-way half pipe rubber bag step forming method. Step 1, determining a plate blank of the three-way half pipe and carrying out blanking processing to obtain a plate of the three-way half pipe; Step 2, a forming process of the three-way half pipe male die; Step 2.1, placing the plate on the positioning grooves of the mold workbench, aligning a center point of the plate with a center point of the three-way half pipe male die to complete positioning, and covering a layer of polyurethane above the plate, and the rubber bag is above the polyurethane; Step 2.2, driving the rubber bag to start pressurizing by using the pressurizing device, the pressure is transmitted to the plate, and the plate is pressed and fixed to the mold workbench; meanwhile, the three-way half pipe male die is driven to move upwards by the driving device below the three-way half pipe male die until the three-way half pipe male die is in contact with the plate, and the position is recorded as an initial position; Step 2.3, continuously increasing the pressurizing pressure of the rubber bag, and meanwhile, starting to form the plate by using the three-way half pipe male die from the initial position under the action of the driving device, the moving distance of the three-way half pipe male die is R; in the process, the pressurizing pressure provided by the pressurizing device is linearly increased to a preset maximum pressure; after the three-way half pipe male die moves R, the three-way half pipe male die is continuously moved by a preset distance and is kept for a first preset time; R is the radius of the three-way pipe fitting; Step 2.4, after the keeping is finished, the rubber bag is depressurized, the three-way half pipe male die is reset, and the plate after forming is taken out; the part is detected, including the acute angle region of the main pipe and the branch pipe of the three-way half pipe, whether the film adhesion degree reaches a preset requirement and whether the thickness meets a standard are checked; if the thickness detection does not pass, the plate is re-blanked; if the film adhesion degree detection does not pass, the next step is performed; Step 3, stamping and shaping of the part; Step 3.1, placing the part on the positioning grooves of the mold workbench again and positioning; then the driving device drives the three-way half pipe male die to move upwards to the initial position and stops; Step 3.2, replace the rubber bag with a three-way half pipe concave die, which is placed on the upper surface of the part and adheres to it; Step 3.3, the three-way half pipe concave die starts to pressurize the upper surface of the part through the pressurizing device, while the three-way half pipe convex die continues to move upward at a preset speed under the drive of the driving device until the three-way half pipe convex die and the three-way half pipe concave die are closed, and the pressure is maintained for a second preset time; Step 3.4, after the pressure maintaining is finished, the three-way half pipe concave die gradually releases the pressure, while the three-way half pipe convex die resets, and the stamped and shaped part is taken out; Step 4, the stamped and shaped part is post-processed to obtain the asymmetric Y-shaped three-way half pipe finished part.

[0010] Further, the plate blank of the three-way half pipe is determined and processed to obtain the plate material of the three-way half pipe, comprising: Select a plate blank with the same wall thickness as the three-way half pipe as the raw material; expand the plate blank model in the finite element software, determine the shape and size of the plate material model for three-way half pipe forming in combination with the numerical model of the three-way half pipe; based on the determined plate material model, cut the plate blank entity to obtain the plate material of the three-way half pipe.

[0011] Further, the pressurizing pressure of the pressurizing device driving the rubber bag increases linearly, and the pressurizing time is set to 0 to 60s, and the three-way half pipe convex die moves upward from the initial position to R.

[0012] Further, the preset distance is R, the upward moving speed of the three-way half pipe convex die is 1mm / s.

[0013] Further, when the maximum thinning rate of the acute angle region is less than 20%, it indicates that the thickness meets the requirements; when the film adhesion degree of the acute angle region is less than 2mm, it indicates that the film adhesion degree meets the requirements.

[0014] Further, the post-processing of the stamped and shaped part comprises: The excess process edge of the stamped and shaped part is cut and trimmed to obtain the asymmetric Y-shaped three-way half pipe finished part which meets the design size and shape requirements; finally, the finished part is subjected to thickness detection, shape re-measurement and surface quality inspection.

[0015] Compared with the prior art, the present application has the following technical features: 1. The method of the present application uses a rubber bag as a concave die and a pressure ring, a rigid die as a convex die, and hydraulic oil as a pressure transmission medium. Through the hydraulic action, the metal plate material is gradually wrapped on the rigid convex die, and the material shaping is fully played, which to some extent relieves the phenomena of wrinkling, cracking and excessive thinning of the plate material.

[0016] 2. The method solves the problem of not sticking film in the acute angle area of the once formed sheet, eliminates the wrinkling defects of the sheet at the top joint of the main pipe and branch pipe, and to some extent reduces the springback of the sheet, while avoiding the rupture of the rubber when forming the acute angle part, prolonging the service life of the rubber, and increasing the yield of the produced parts.

[0017] 3. The method is not only suitable for Y-shaped three-way half pipe of asymmetric structure, but also suitable for three-way half pipe rubber bag forming of other different shapes. By using the method of the application, only the rigid mold needs to be modified according to the specific shape and size, which increases the application range of the method. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a front view of the asymmetric Y-shaped three-way half pipe; Figure 2 is a right view of the asymmetric Y-shaped three-way half pipe; Figure 3 is a top view of the asymmetric Y-shaped three-way half pipe; Figure 4 is a perspective view of the asymmetric Y-shaped three-way half pipe; Figure 5 is a schematic view of the processed sheet in the embodiment of the application; Figure 6 is a schematic view of the cross section of the forming device of the application; Figure 7 is a schematic view of the three-dimensional model section of the forming device of the application; Figure 8 is a schematic view of the cross section of the sheet starting to form in the embodiment of the application; Figure 9 is a schematic view of the model of the formed part; Figure 10 is a schematic view of the cross section of the stamping and shaping in the embodiment of the application; Figure 11 is a schematic view of the three-dimensional model section of the stamping and shaping in the embodiment of the application; Figure 12 is a thickness cloud chart of the formed part in the embodiment of the application.

[0019] Explanation of reference signs: 1 rubber bag, 2 sheet, 3 three-way half pipe punch, 4 mold workbench, 5 driving device, 6 positioning groove, 7 three-way half pipe recess. DETAILED DESCRIPTION

[0020] Considering the shortcomings of the rubber bag forming of the three-way half pipe with complex structure, in order to solve the problem of wrinkling and cracking defects of such components in forming, the asymmetric Y-shaped three-way half pipe rubber bag step-by-step forming device and method are provided, which are specifically described as follows: First, the asymmetric Y type tee half pipe rubber bag step forming device is constructed;As shown in Figures 6 to 8 The device includes a mold workbench 4;The inside of the mold workbench 4 is provided with a forming cavity in the longitudinal direction, and a circle of positioning grooves 6 is arranged on the top of the forming cavity in the circumferential direction for placing the forming sheet 2 of the tee half pipe;A tee half pipe punch 3 is arranged in the forming cavity, and a driving device 5 capable of driving the tee half pipe punch 3 to move in the longitudinal direction is arranged below the tee half pipe punch 3;A rubber bag 1 is arranged above the mold workbench 4, and the rubber bag 1 is installed on a pressurizing device capable of providing a preset pressing force for the rubber bag 1;The rubber bag 1 can be disassembled and replaced with a tee half pipe recess 7.

[0021] Among them, the driving device 5 realizes axial driving through cylindrical guide hole cooperation, ensuring the accuracy of axial movement;The driving device 5 may, for example, adopt a hydraulic device.

[0022] In the scheme, the tee half pipe punch 3 and the tee half pipe recess 7 are both rigid molds, and the shapes thereof are matched with the asymmetric tee half pipe to be processed;The acute angle region and the obtuse angle region of the tee half pipe punch 3 are both chamfered.

[0023] On the basis of the above-mentioned device, the asymmetric Y type tee half pipe rubber bag step forming method provided by the application comprises the following steps: Step 1, select a slab with the same thickness as the tee half pipe as the raw material;Unfold the slab model in the finite element software, determine the shape and size of the sheet model for tee half pipe forming in combination with the numerical model of the tee half pipe;Based on the determined sheet model, cut the slab entity to obtain the sheet 2 of the tee half pipe.

[0024] In an embodiment of the application, referring to Figures 1 to 4 DP600 material is used as the slab, the thickness of the asymmetric Y type tee half pipe to be formed is 2mm, and the diameter is 100mm;The length of the main pipe of the tee half pipe is 600mm, the length of the branch pipe thereon is 400mm, and the maximum angle between the main pipe and the branch pipe is 130°, thereby forming the asymmetric Y type structure. The elastic modulus of the DP600 material is 210GPa, the Poisson's ratio is 0.3, and the density is 7.8E-6kg / mm 3 .

[0025] In this embodiment, DP600 material with a thickness of 2mm is selected as the slab, and the slab model and the numerical model of the tee half pipe are first constructed in the finite element software Pam-Stamp;The slab is unfolded by using the unfolding function in the software, and the shape and size of the sheet model are calculated inversely, as shown in Figure 5 After obtaining the shape and size information, the entity is processed;The slab 2 is obtained by cutting the slab entity by using a cutting machine;Ensure that the surface of the sheet 2 is free of scratches, and clean and treat the surface.

[0026] Step 2, forming process of the three-way half pipe punch.

[0027] Step 2.1, place the plate 2 on the positioning groove 6 of the mold workbench 4, align the center point of the plate 2 with the center point of the three-way half pipe punch 3 to complete positioning, and cover a layer of polyurethane above the plate 2, and the rubber bag 1 above the polyurethane.

[0028] Figure 7 And Figure 8 In the embodiment of the application, the thickness of the polyurethane is 6mm.

[0029] Step 2.2, drive the rubber bag 1 to start pressurization by using the pressurizing device, and the pressure is transmitted to the plate 2, and the plate 2 is pressed and fixed to the mold workbench 4; at the same time, the three-way half pipe punch 3 is driven upward by the driving device 5 below until it comes into contact with the plate 2, which is recorded as the initial position.

[0030] In the embodiment of the application, the pressurization value of the pressurizing device is adjusted according to the material and size of the plate 2; for example, in this embodiment, for DP600 material, a linear pressurization mode is adopted, and the maximum pressure is 14Mpa; when the pressure increases to 2Mpa, the plate 2 is pressed and fixed to the mold workbench 4, as shown in Figure 9 .

[0031] Step 2.3, continue to increase the pressurization pressure of the rubber bag 1, and at the same time, under the action of the driving device 5, the plate 2 is formed by using the three-way half pipe punch 3 from the initial position, and the moving distance of the three-way half pipe punch 3 is R; in this process, the pressurization pressure provided by the pressurizing device is linearly increased to the preset maximum pressure; after the three-way half pipe punch 3 moves R, it continues to move upward by a preset distance and maintains pressure for a first preset time; wherein R is the radius of the three-way pipe (i.e. the three-way pipe formed by splicing two three-way half pipes).

[0032] In the embodiment of the application, the pressurization pressure of the pressurizing device driving the rubber bag 1 is linearly increased, the pressurization time is set to 0-60s, the three-way half pipe punch 3 moves upward from the initial position (recorded as 0mm) to R=50mm, and the plate 2 is gradually formed in this process; when the pressurization pressure reaches 14Mpa, the three-way half pipe punch 3 reaches the position of 50mm; in order to ensure the size integrity of the final part during cutting, the moving amount of the three-way half pipe punch 3 needs to be increased by R, that is, the three-way half pipe punch 3 continues to move upward by 5mm and then stops, at which time the pressure maintaining state is entered, and maintained for 15s.

[0033] Step 2.4, after the holding pressure is completed, the rubber bag 1 is depressurized, and the three-way half pipe punch 3 is reset, and the formed part of the sheet material 2 is taken out; the part is detected, including the acute angle area where the main pipe and the branch pipe of the three-way half pipe are connected, to check whether the film adhesion degree meets the preset requirements and the thickness meets the standard; if the thickness detection fails, the sheet material is reprocessed, and the pressing pressure, pressing rate and other parameters are adjusted as necessary; if the film adhesion degree detection fails, the next step is performed.

[0034] In the embodiment of the present application, first, the thickness of the acute angle area is tested; when the maximum thinning rate is less than 20%, it indicates that the thickness meets the requirements; in the forming process of the present embodiment, the acute angle area of the three-way half pipe punch 3 is rounded, the contact area is increased, and the thickness of the formed part is obviously increased, with a minimum thickness of 1.929 mm; compared with the concave die, the upper surface of the three-way half pipe punch 3 is in contact with the sheet material 2 during the forming process, which supports the sheet material 2 and relieves the instability wrinkling defect, as shown in Figure 9 Secondly, the film adhesion degree is tested; when the film adhesion degree of the acute angle area is less than 2 mm, it indicates that it meets the basic requirements, otherwise the processing flow needs to be further optimized. Since the stress area of the rubber bag 1 is large, the pressure at the acute angle area is not enough, resulting in limited deformation and extrusion, and the material flow of the sheet material at the acute angle is limited, while excessive pressure will cause the rubber bag 1 to break at the acute angle area; therefore, the formed part does not have enough adhesion to the die, with a maximum spacing of 17.194 mm, which does not meet the forming requirements, and the next stamping and shaping needs to be performed.

[0035] Step 3, stamping and shaping of the part.

[0036] If the film adhesion of the part at the acute angle area is not enough after forming with the three-way half pipe punch 3, it indicates that the sheet material 2 does not fully adhere to the surface of the three-way half pipe punch 3, resulting in insufficient local forming and subsequent dimensional deviation; to solve this problem, the present application designs a second stamping and shaping process, which uses the structural rigidity of the three-way half pipe concave die 7 to cause plastic deformation of the material in the acute angle rounding area, increase the material flow, and increase the film adhesion of the part at the acute angle, to meet the requirements of the three-way half pipe formed part, as shown in Figure 10 11 The specific method is as follows: Step 3.1, place the part on the positioning groove 6 of the die workbench 4 and position it; then drive the three-way half pipe punch 3 to move upward to the initial position and stop.

[0037] Step 3.2, replace the rubber bag 1 with the three-way half pipe concave die 7, place it on the upper surface of the part and adhere to it.

[0038] ​​Step 3.3, the upper surface of the part is started to be pressed by the three-way half pipe concave die 7 driven by the pressing device, while the three-way half pipe convex die 3 continues to move upwards at a preset speed under the driving of the driving device 5, until the three-way half pipe convex die 3 and the three-way half pipe concave die 7 are closed, and then the pressure is maintained for a second preset time.

[0039] In the embodiment of the application, the moving speed of the three-way half pipe convex die 3 upwards is 1 mm / s, and the pressure maintaining time is 15 s.

[0040] Step 3.4, after the pressure maintaining is finished, the three-way half pipe concave die 7 is gradually depressurized, while the three-way half pipe convex die 3 is reset, and the stamped and shaped part is taken out.

[0041] Step 4, trimming of the part.

[0042] The excess process edges on the part are cut and trimmed to obtain the asymmetric Y-shaped three-way half pipe finished product meeting the design size and shape requirements; finally, the thickness detection, shape re-measurement and surface quality inspection are performed on the finished product to ensure that the final product meets the design tolerance and use requirements.

[0043] The method provided in the embodiment can be used for process simulation verification, and the specific settings are as follows: The asymmetric Y-shaped three-way half pipe rubber bladder convex die forming finite element model is constructed by using the PAM-STAMP software to simulate the rubber bladder forming process: the die is a rigid structure, the Mooney-Rivlin model formula I is used to describe the elastic deformation behavior of the rubber bladder, the rubber thickness is set to 6 mm, and the parameters are shown in Table 1.

[0044] Formula I In formula I, represents a strain energy density function; , represents a material constant, which describes the shear behavior of the material; , represents the first and second stress tensor invariants.

[0045] Table 1: Rubber material model parameters

[0046] It is assumed that the sheet metal is isotropic, and the krupkowsky law hardening model formula II is used: Formula II In formula II, is the flow stress, is the strength coefficient, is the initial strain, is the equivalent plastic strain, The hardening index is 1.1052 GPa, The hardening index is 0.174, The hardening index is 0.174, The hardening index is 0.174,

[0047] The friction coefficients of the rubber bag and the sheet, the sheet and the mold, and the rubber bag and the three-way half-pipe mold are all set to 0.1. The maximum pressure of the rubber bag is set to 14 MPa, and the time is set to 60 ms. The boundary conditions are determined according to the actual boundary conditions, the liquid pressure is applied to the upper surface of the rubber bag, the rubber bag is fixed around, the three-way half-pipe punch moves axially through displacement control, and the blank holder is fixed and constrained. The specific parameters are as shown in the following table 2.

[0048] Table 2: Contact settings for one-time forming

[0049] Based on the stamping and forming process of adding the second step, a three-dimensional finite element model is constructed, the surface contact settings are shown in table 3, and the simulation of stamping forming is carried out again.

[0050] Table 3: Contact settings for two-time forming

[0051] The detection results of the final finished product in the embodiment of the application are shown in Figure 12 The thinnest part is in the acute angle area, which is 1.76 mm, and the thinning rate is 20%, which meets most of the production requirements, and a high-quality asymmetric Y-shaped three-way half-pipe finished product is obtained.

[0052] The above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. An asymmetric Y-shaped three-way semi-tube rubber bladder stepwise forming device, characterized in that, The mold includes a mold worktable (4); a forming cavity is arranged longitudinally inside the mold worktable (4), and a positioning groove (6) is arranged circumferentially on the top of the forming cavity for placing the forming sheet (2) of the three-way half-pipe; a three-way half-pipe punch (3) is arranged in the forming cavity, and a driving device (5) is below it that can drive the three-way half-pipe punch (3) to move longitudinally; a rubber bladder (1) is arranged above the mold worktable (4), and the rubber bladder (1) is installed on a pressurizing device that can provide a preset clamping force to the rubber bladder (1); the rubber bladder (1) can be disassembled and replaced with a three-way half-pipe die (7).

2. The asymmetric Y-shaped three-way semi-tube rubber bladder step-by-step forming device according to claim 1, characterized in that, The three-way semi-tube punch (3) and the three-way semi-tube die (7) are both rigid molds, and their shapes match the asymmetrical three-way semi-tube to be processed; the acute and obtuse angle areas of the three-way semi-tube punch (3) are rounded.

3. A stepwise forming method for an asymmetric Y-shaped three-way semi-tubular rubber bladder, characterized in that, include: Step 1: Determine the blank of the tee half pipe and perform blanking processing to obtain the tee half pipe blank (2); Step 2, the forming process of the tee half-pipe punch; Step 2.1: Place the sheet metal (2) on the positioning groove (6) of the mold worktable (4) so ​​that the center point of the sheet metal (2) is aligned with the center point of the three-way half-pipe punch (3) to complete the positioning, and cover the sheet metal (2) with a layer of polyurethane, with a rubber bladder (1) on top of the polyurethane. Step 2.2: Use the pressurizing device to drive the rubber bladder (1) to start pressurizing, and the pressure is transmitted to the sheet metal (2). The sheet metal (2) is pressed and fixed on the mold worktable (4). At the same time, the three-way half-pipe punch (3) is driven by the driving device (5) below it to move upward until it comes into contact with the sheet metal (2), which is recorded as the initial position. Step 2.3: Continue to increase the pressure of the rubber bladder (1), and at the same time, under the action of the driving device (5), the sheet metal (2) is formed from the initial position using the three-way half-pipe punch (3). The moving distance of the three-way half-pipe punch (3) is R. During this process, the pressure provided by the pressurizing device increases linearly to the preset maximum pressure. After the three-way half-pipe punch (3) moves R, it continues to move upward a preset distance and holds pressure for a first preset time. R is the radius of the three-way fitting. Step 2.4: After the pressure holding is completed, the rubber bladder (1) is depressurized and the tee half-pipe punch (3) is reset. The part formed by the sheet metal (2) is taken out. The part is inspected, including the acute angle area where the main pipe and branch pipe of the tee half-pipe are connected. Check whether the film adhesion meets the preset requirements and whether the thickness meets the standard. If the thickness test fails, the material is re-cut and processed. If the film adhesion test fails, proceed to the next step. Step 3: Stamping and shaping of the parts; Step 3.1: Place the part back into the positioning groove (6) of the mold worktable (4) and position it; then drive the three-way half-pipe punch (3) upward to the initial position and stop. Step 3.2, replace the rubber bladder (1) with a three-way half-pipe mold (7), place it on the upper surface of the part and fit it; Step 3.3: The pressure device drives the three-way half-pipe die (7) to start applying pressure to the upper surface of the part. At the same time, the three-way half-pipe punch (3) continues to move upward at a preset speed under the drive of the drive device (5) until the three-way half-pipe punch (3) and the three-way half-pipe die (7) are closed, and the pressure is maintained for a second preset time. Step 3.4: After the pressure holding is completed, the pressure of the three-way half-pipe die (7) is gradually released, and at the same time the three-way half-pipe punch (3) is reset, and the stamped and shaped parts are taken out. Step 4: Post-process the stamped and shaped parts to obtain the asymmetric Y-shaped tee half-pipe finished parts.

4. The stepwise forming method for an asymmetric Y-shaped three-way semi-tube rubber bladder according to claim 3, characterized in that, The blank of the tee half-pipe is determined and processed to obtain the tee half-pipe sheet (2), including: Select a slab with the same wall thickness as the tee half-pipe as the raw material; unfold the slab model in the finite element software, and combine it with the digital model of the tee half-pipe to determine the shape and size of the plate model used for forming the tee half-pipe; based on the determined plate model, cut the slab entity to obtain the plate material of the tee half-pipe (2).

5. The stepwise forming method for an asymmetric Y-shaped three-way semi-tube rubber bladder according to claim 3, characterized in that, The pressurizing device drives the rubber bladder (1) to increase the pressurizing pressure linearly. The pressurizing time is set from 0 to 60 seconds. The three-way half-pipe punch (3) moves upward from the initial position to R.

6. The stepwise forming method for an asymmetric Y-shaped three-way semi-tube rubber bladder according to claim 3, characterized in that, The preset distance is R, the upward movement speed of the three-way half-pipe punch (3) is 1 mm / s.

7. The stepwise forming method for an asymmetric Y-shaped three-way semi-tube rubber bladder according to claim 3, characterized in that, When the maximum thinning rate of the acute angle area is less than 20%, it indicates that the thickness meets the requirements; when the film adhesion of the acute angle area is less than 2mm, it indicates that the film adhesion meets the requirements.

8. The stepwise forming method for an asymmetric Y-shaped three-way semi-tube rubber bladder according to claim 3, characterized in that, The post-processing of the stamped and shaped parts includes: After stamping and shaping, excess process edges on the parts are trimmed and trimmed to obtain asymmetrical Y-shaped tee half-pipe finished parts that meet the design dimensions and shape requirements; finally, the finished parts are subjected to thickness testing, shape re-measurement and surface quality inspection.

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