Bidirectional bending special-shaped variable-diameter pipe forming method, mold and device for aero-engine

Abstract

The invention discloses a forming method, a forming die and a forming device for a bi-directional bending special-shaped variable-diameter pipe for an aero-engine. A split type combination die is adopted, pre-bending in the vertical direction is completed through die assembly of a combination male die and a combination female die, and then pre-bending in the horizontal direction is completed through die assembly of a side pushing female die and the combination female die; the preforming of the two-way bending special-shaped variable-diameter pipe is completed in the same set of die. The two actions of pipe blank sealing and material supplementing are achieved by combining the matching combination of the two-section type slopes of the wedge transmission component and the sealing push head, according to the change of the slope angle, the wedge transmission component can conduct accurate material supplementing and forming on the pipe fitting during high-pressure forming, meanwhile, the situation that fluctuation possibly exists during hydraulic loading matching is effectively eliminated, and the sealing effect is improved. The molded surface machining precision of the bidirectional bending special-shaped variable-diameter pipe in internal high-pressure forming is improved, and the part quality and the machining qualification rate are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of bidirectionally bent special-shaped tube forming, and more particularly to a bidirectionally bent special-shaped variable-diameter tube forming method, a forming die and a forming device for an aero-engine. Background Art

[0002] Lightweighting aircraft engine piping is a key technology for improving engine performance, reducing fuel consumption, and lowering emissions. To achieve this goal, thin-walled and curved designs are generally adopted to reduce pipe weight, optimize pipe curves, and reduce straight pipe sections to reduce unnecessary weight. Based on these requirements, aircraft engine piping is often characterized by thin-walled, special-shaped, curved, and reducer pipes. Due to the complex structure and shape of special-shaped pipes, multiple sets of molds are often required for assembly and matching, and the production process is also relatively complex. This leads to low production efficiency and high cost. Therefore, it is necessary to streamline the special-shaped pipe production process and molds to reduce costs and improve production efficiency.

[0003] CN202591342U discloses a pipe bending and forming device that uses a multi-shaped bending and bulging die that cooperates with the pipe fitting, including an upper die steel block and a lower die steel block that cooperate with the pipe fitting, an upper die base and a lower die base arranged on the workbench for mounting the upper die steel block and the lower die steel block, and a hydraulic cylinder connected to the hydraulic bulging die through a punch mechanism. This patent obtains high-pressure liquid by squeezing the liquid in the hydraulic cylinder through the movement of the hydraulic cylinder piston. The high-pressure liquid is injected into the pipe blank through the punch, so that the pipe blank obtains the liquid pressure required for bulging. The pipe bending and forming device provided by this patent realizes a design that can perform both special-shaped bending of pipe fittings and internal high-pressure forming actions on a set of internal high-pressure forming dies. At the same time, by controlling the piston stroke to control the axial force, and by adjusting the overflow value of the overflow valve to control the size of the tube forming liquid pressure, the forming pressure of the forming equipment is gradually increased, so that the transition radius of the tube gradually abuts the hydraulic bulging die. This avoids the defects of the tube end being prone to instability and wrinkling due to excessive friction when axial feeding and internal pressure shaping are carried out simultaneously, and the bulging area being prone to rupture due to insufficient feeding. This can greatly improve the forming limit of the tube and reduce costs. Although this patent can reduce the number of sets of dies and processes for special-shaped tubes, there are still some areas that need to be improved: (1) This patent is only applicable to the forming of unidirectional special-shaped pipe fittings. When the special-shaped pipe needs to be shaped in two directions, it is still necessary to use multiple sets of molds and processes to process in different directions. Once multiple processes are carried out, it is easy to have problems such as the springback of the pre-bending forming surface causing poor dimensional accuracy, or failure of the internal high-pressure liquid seal; (2) When using a double-action liquid filling molding machine for bulging, the main cylinder stroke and the side push cylinder stroke are easily fluctuated when matched with the hydraulic loading during internal high-pressure forming due to differences in synchronization, resulting in quality problems such as uneven wall thickness of special-shaped pipe fittings and wrinkling of the mold surface.

[0004] (3) The forming liquid pressure of the tube blank is controlled by the piston control of the side push hydraulic cylinder and the overflow value of the overflow valve. In the early stage of the bulging stage, the force is relatively small and easy to control. In the later stage, the force required is large, which is difficult to control and unstable. It is easy to cause wrinkles or even ruptures on the surface of the tube fitting due to deviation in feeding and untimely feeding.

[0005] To address the aforementioned issues, CN104226776B discloses a thin-walled metal tube impact hydraulic bulging system that utilizes two inclined sliders fixed to an upper worktable that move with the worktable and compress horizontal guide pillars to achieve sealing of the thin-walled metal tube. As the upper worktable continues to descend, the upper and lower molds close, and the thin-walled metal tube undergoes impact hydraulic bulging under the action of the liquid within and the external impact force. This patent utilizes the stroke of the upper worktable's main cylinder to simultaneously control the longitudinal direction of the mold and the lateral thrust pressure, avoiding potential fluctuations in the hydraulic loading matching between the lateral thrust cylinder stroke and the main cylinder stroke during hydroforming. Furthermore, the horizontal movement of the two horizontal guide pillars achieves sealing and axial feeding of the thin-walled metal tube during the bulging process. However, in the forming of special-shaped tubes, different hydraulic pressures must be applied at different stages to achieve deformation of the tube blank, thereby precisely controlling feeding and forming of the special-shaped tube. Clearly, the single inclined surfaces of the inclined sliders and horizontal guide pillars in this patent cannot align with the hydraulic loading curve of the special-shaped tube to achieve precise feeding and hydraulic control. Summary of the Invention

[0006] The main technical problem to be solved by the present invention is to provide a bidirectional bending special-shaped reducer tube forming mold and device for aircraft engines in view of the shortcomings of the existing technology in the process of forming bidirectional bending special-shaped reducer tubes, such as complex molds and processes, easy sealing failure, and low accuracy of feeding and hydraulic control.

[0007] Another technical problem solved by the present invention is to provide a method for forming a bidirectionally bent special-shaped variable diameter tube for an aero-engine.

[0008] The purpose of the present invention is achieved through the following technical solutions: A bidirectional bending special-shaped reducer tube forming die for aircraft engines, comprising an upper die plate, a lower die plate, a combined die, a pressing block, a sealing pusher head and an inclined wedge transmission component; The combined die includes a combined female die 1, a combined female die 2, a side push female die 1, a side push female die 2 and a combined male die. The combined female die 1 and the combined female die 2 are fixed at intervals on the lower template. The side push female die 1 and the side push female die 2 are slidably connected to the lower template. The side push female die 1 and the side push female die 2 can be combined with the combined female die 1 and the combined female die 2. The combined male die can be combined with the combined female die 1, the combined female die 2, the side push female die 1 and the side push female die 2 to form a profile of a bidirectionally curved special-shaped reducer tube. The upper template is provided with a pressing block for fixing the tube blanks at both ends of the female mold, and the two ports of the tube blank in the combined mold are provided with sealing push heads. The lower template is provided with a sliding slider, one end of the slider is connected to the sealing push head, and the other end is provided with an upper inclined surface 1 and a lower inclined surface 1 with different inclination angles; the upper template is also provided with an inclined wedge transmission component, and the inclined wedge transmission component includes a lower inclined surface 2 that cooperates with the upper inclined surface 1 of the slider, and an upper inclined surface 2 that cooperates with the lower inclined surface 1 of the slider; The sealing pusher head includes an inlet section, a flexible sealing section, a support section, a rigid sealing section and a feeding section which are connected in sequence. The lengths of the flexible sealing section, the support section and the rigid sealing section are the same as the feed stroke of the upper inclined surface 1 of the slider and the lower inclined surface 2 of the inclined wedge transmission component. The length of the feeding section is the same as the feed stroke of the lower inclined surface 1 of the slider and the upper inclined surface 2 of the inclined wedge transmission component. The sealing pusher head is also provided with a liquid filling port for filling liquid into the tube blank.

[0009] Furthermore, a slide rail is provided on the lower template, and the side push female mold 1 and the side push female mold 2 are connected to the lower template via the slide rail.

[0010] Furthermore, the pressing block is connected to the upper template via a spring.

[0011] Furthermore, a liquid filling channel is provided in the slider, and the liquid filling channel is connected to the liquid filling port of the sealing push head.

[0012] Furthermore, a groove is provided on the outer periphery of the flexible sealing section, and a rubber sealing ring is provided in the groove.

[0013] Furthermore, the upper inclined surface 1 of the slider has an inclination angle of 45°, and the lower inclined surface 1 of the slider has an inclination angle of 50~60°; the upper inclined surface 2 of the inclined wedge transmission component has an inclination angle of 50~60°, and the lower inclined surface 2 of the inclined wedge transmission component has an inclination angle of 45°.

[0014] Furthermore, wear-resistant blocks are provided on the upper inclined surface 2 and the lower inclined surface 2 of the wedge transmission component.

[0015] Furthermore, blocks are provided on both sides of the slider of the lower template. During the expansion process, the blocks play a supporting role to prevent the seal from failing due to excessive hydraulic counter-expansion force.

[0016] A bidirectionally curved special-shaped reducer tube forming device for aircraft engines comprises the above-mentioned bidirectionally curved special-shaped reducer tube forming die for aircraft engines and a double-action liquid filling and stretching forming device, wherein the inner slider of the double-action liquid filling and stretching forming device is connected to the combined punch, the outer slider of the double-action liquid filling and stretching forming device is connected to the upper template, and the liquid filling device of the double-action liquid filling and stretching forming device is connected to the liquid filling port of the sealing push head.

[0017] A method for forming a bidirectionally bent special-shaped variable diameter tube for an aircraft engine, comprising the following steps: S1. Place the tube blank on a combined female mold, a combined female mold, two, plug the ends of the seal push head into the lead-in section, and install the slider on the side of the seal push head; S2. The upper template is driven downward, with the pressure blocks pressing against both ends of the tube. The upper template is then controlled to continue its downward movement. The lower inclined surface 2 of the wedge drive component contacts the upper inclined surface 1 of the slider. The downward force of the wedge drive component pushes the slider horizontally. The flexible sealing section of the sealing pusher performs the first stage of sealing. The sealing pusher then pushes the supporting and rigid sealing sections into the tube to complete the second stage of sealing. S3. After the tube is filled with liquid and a certain hydraulic pressure is applied, the combined punch is driven downward until it is engaged with the combined female die 1 and the combined female die 2, completing the vertical pre-bending of the tube. The side pusher dies 1 and 2 are then pushed together with the combined female die 1 and the combined female die 2 to complete the horizontal pre-bending of the tube. S4. Control the upper template downward, driving the upper inclined surface 2 of the inclined wedge transmission component to cooperate with the lower inclined surface 1 of the slider. The slider continues to push the feeding section of the sealing pusher to the tube blank. At the same time, according to the loading hydraulic curve, a higher liquid chamber pressure is applied to match the advancement of the sealing pusher, achieving expansion of the special-shaped surface inside the tube.

[0018] Furthermore, the rigid sealing section is inclined and can cooperate with the pressing block to perform rigid extrusion sealing on the tube blank, and the extrusion amount is to thin the material from 1 times the wall thickness to 0.6~0.7 times the wall thickness.

[0019] Compared with the prior art, the beneficial effects are: The present invention adopts a split combined die, including a combined female die, a side-pushing female die and a combined male die. The combined male die and the combined female die are combined to complete the pre-bending in the vertical direction, and the side-pushing female die and the combined female die are combined to complete the pre-bending in the horizontal direction, thereby achieving the pre-forming of bidirectionally bent special-shaped reducer tubes in the same set of dies. At the same time, the present invention utilizes the combination of the two-stage inclined surface of the inclined wedge transmission component and the sealing push head, which not only ensures the sealing effect of the high pressure inside the tube blank, but also effectively solves the current problem of positioning the tube blank in the high-pressure forming mold and the easy failure of the tube end seal, improves the sealing performance of the part forming, improves the qualified rate of the part processing, and reduces the processing cycle and cost of the part; and accurately feeds the material in coordination with the loaded hydraulic curve during the high-pressure forming of the pipe fitting, avoiding wrinkling of the tube wall caused by premature feeding or rupture of the tube wall caused by untimely feeding, etc., thereby improving the forming quality of the bidirectionally bent special-shaped reducer tube, and at the same time effectively eliminating the possible fluctuations in the side push cylinder stroke and the main cylinder stroke in the traditional internal high-pressure equipment when matching with the hydraulic loading during the internal high-pressure forming, thereby improving the surface processing accuracy of the bidirectionally bent special-shaped reducer tube in the internal high-pressure forming, and effectively improving the part quality and processing qualified rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of a bidirectionally bent special-shaped reducer; a is the model structure diagram, b is the front view, and c is the top view; Figure 2 It is a high pressure forming die for bidirectional bending special-shaped reducer pipes; Figure 3 It is an exploded view of the combined molding component model; Figure 4 It is a schematic diagram of the sealing push head; Figure 5 It is a schematic diagram of the wedge transmission component and the slider; Figure 6 This is a diagram of the inclined wedge transmission components.

[0021] Among them, 1 is the upper template, 2 is the pressing block, 3 is the lower template, 4 is the combined punch, 5 is the combined female mold 1, 6 is the side push female mold 1, 7 is the combined female mold 2, 8 is the sealing push head, 801 is the introduction section, 802 is the flexible sealing section, 803 is the supporting section, 804 is the rigid sealing section, 805 is the feeding section, 9 is the slider, 901 is the upper inclined surface 1, 902 is the lower inclined surface 1, 10 is the inclined wedge transmission component, 1001 is the upper inclined surface 2, 1002 is the lower inclined surface 2, 11 is the stop block, and 12 is the wear-resistant block. DETAILED DESCRIPTION

[0022] The present invention will be further explained and illustrated below with reference to the embodiments, but the specific embodiments do not limit the present invention in any form.

[0023] Example 1 This embodiment provides a bidirectional bending special-shaped reducer tube forming die for an aircraft engine, such as Figures 2 and 3 , including an upper template 1, a lower template 3, a combined mold, a pressing block 2, a sealing push head 8 and a wedge transmission component 10.

[0024] The combined mold comprises a first combined female mold 5, a second combined female mold 7, a first side push female mold 6, a second side push female mold 2, and a combined male mold 4. The upper surfaces of the first combined female mold 5 and the second combined female mold 7 have the profiles of the two ends of the shaped reducer, and are fixed to the lower mold plate 3 at intervals. The first side push female mold 6 and the second side push female mold 2 are slidably connected to the lower mold plate 3 and can be combined with the first combined female mold 5 and the second combined female mold 7 to form the lower profile female mold for the bidirectionally curved shaped reducer. The lower surface of the combined male mold 4 has the upper profile of the shaped reducer, which can be combined with the first combined female mold 5, the second combined female mold 2, the first side push female mold 1, and the second side push female mold 2.

[0025] The upper mold plate 1 is provided with a pressing block 2 for fixing the tube blanks at both ends of the female mold, and the two ports of the tube blank in the female mold are provided with sealing push heads 8. Figures 5 and 6 The lower template 3 is provided with a slidable slider 9, one end of the slider 9 is connected to the sealing push head 8, and the other end is provided with an upper inclined surface 901 and a lower inclined surface 902 with different inclination angles; the upper template 1 is also provided with an inclined wedge transmission component 10, and the inclined wedge transmission component 10 includes a lower inclined surface 1002 that cooperates with the upper inclined surface 901 of the slider 9, and an upper inclined surface 1001 that cooperates with the lower inclined surface 902 of the slider 9; The sealing push head 8 is provided with a liquid filling port which is connected to the interior of the tube blank. Liquid is filled into the tube blank through the liquid filling port to realize internal high pressure bulging. Figure 4 The sealing pusher 8 comprises an introduction section 801, a flexible sealing section 802, a support section 803, a rigid sealing section 804, and a feeding section 805, which are connected in sequence. The introduction section 801 guides the tube blank, allowing it to be smoothly introduced into the sealing pusher 8. The flexible sealing section 802 performs a flexible seal. The support section 803 supports the roundness of the tube blank and prepares for subsequent rigid sealing. The rigid sealing section 804 cooperates with the pressing block 2 to perform a rigid thinning seal on the tube. The feeding section 805 is used to push the tube blank during the transverse feed of the sealing pusher 8, feeding material into the mold cavity during the internal high-pressure forming process, reducing material thinning during bulging and improving formability. Among them, the lengths of the flexible sealing section 802, the supporting section 803 and the rigid sealing section 804 are the same as the feed strokes of the upper inclined surface 901 of the slider 9 and the lower inclined surface 1002 of the inclined wedge transmission component 10, and the length of the feeding section 805 is the same as the feed strokes of the lower inclined surface 902 of the slider 9 and the upper inclined surface 1001 of the inclined wedge transmission component 10.

[0026] Example 2 This embodiment provides a bidirectional bending special-shaped reducer tube forming die for an aircraft engine, such as Figures 2 and 3 , including an upper template 1, a lower template 3, a combined mold, a pressing block 2, a sealing push head 8 and a wedge transmission component 10.

[0027] The combined mold comprises a combined female mold 5, a combined female mold 7, a side push female mold 6, a side push female mold 2, and a combined punch 4. The upper surfaces of the combined female mold 5 and the combined female mold 2 7 have the profiles of the two ends of the special-shaped reducer, and the two are fixed to the lower mold plate 3 at intervals. The lower mold plate 3 is provided with a slide rail, and the side push female mold 6 and the side push female mold 2 are connected to the lower mold plate 3 via the slide rail. The side push female mold 1 6 and the side push female mold 2 can be combined with the combined female mold 1 5 and the combined female mold 2 7 to form the lower profile female mold for the bidirectionally curved special-shaped reducer. The lower surface of the combined punch 4 is provided with the upper profile male mold for the special-shaped reducer. The combined punch 4 can be combined with the combined female mold 1 5, the combined female mold 2 7, the side push female mold 1 6, and the side push female mold 2 to form the profile of the bidirectionally curved special-shaped reducer.

[0028] The upper mold plate 1 is provided with a pressing block 2 for fixing the tube blanks at both ends of the female mold, and the pressing block 2 is connected to the upper mold plate 1 through a nitrogen spring. Figures 5 and 6 The two ports of the tube blank in the combined mold are provided with sealing pushers 8, and the slider 9 is connected to the lower mold plate 3 through a linear slide rail. One end of the slider 9 is connected to the sealing pusher 8, and the other end is provided with an upper inclined surface 901 with an inclination angle of 45 degrees and a lower inclined surface 902 with an inclination angle of 60 degrees. The upper mold plate 1 is also provided with an inclined wedge transmission component 10, which includes a lower inclined surface 1002 that fits with the upper inclined surface 901 of the slider 9, and an upper inclined surface 1001 that fits with the lower inclined surface 902 of the slider 9. Wear-resistant blocks 12 are provided on the upper inclined surface 1001 and the lower inclined surface 1002 of the inclined wedge transmission component 10. The angles of the lower inclined surface 902 of the slider 9 and the upper inclined surface 1001 of the inclined wedge transmission component 10 can be selected to match the appropriate angle according to the adjustment of the loading hydraulic pressure curve of the special-shaped tube, preferably in the range of 50 to 60 degrees, so as to achieve dual precise control of the loading hydraulic pressure and the feeding of the material, thereby ensuring the quality of the bulging. Stoppers 11 are further provided on both sides of the slider 9 of the lower template 3 to play a supporting role and prevent the seal from failing due to excessive hydraulic back-expansion force.

[0029] The sealing push head 8 is provided with a liquid filling port connected to the inside of the tube blank, and the slider 9 is provided with a liquid filling channel and connected to the liquid filling port of the sealing push head 8. Liquid can be filled into the tube blank from the liquid filling port through the liquid filling channel to achieve internal high-pressure bulging. Figure 4The sealing pusher 8 comprises an introduction section 801, a flexible sealing section 802, a support section 803, a rigid sealing section 804, and a feeding section 805. The lengths of the flexible sealing section 802, support section 803, and rigid sealing section 804 are the same as the feed stroke of the upper inclined surface 1 901 of the slider 9 and the lower inclined surface 2 1002 of the wedge transmission component 10. The feeding section 805 is the same as the feed stroke of the lower inclined surface 1 902 of the slider 9 and the upper inclined surface 2 1001 of the wedge transmission component 10. The introduction section 801 guides the tube blank, ensuring smooth introduction into the sealing pusher 8. A sealing rubber ring is placed in the groove of the flexible sealing section 802 for flexible sealing. The support section 803 supports the roundness of the tube blank and prepares for subsequent rigid sealing. The rigid sealing section 804 is an inclined surface that cooperates with the pressing block 2 to rigidly squeeze and seal the tube, thinning the material from 1x the stock thickness to 0.6-0.7x the stock thickness. The feeding section 805, which pushes the tube blank during the transverse feed of the sealing pusher 8, feeds material into the die cavity during the hydroforming process, minimizing material thinning during bulging and improving formability.

[0030] Example 3 A bidirectionally curved, shaped, and variable-diameter tube forming device for aircraft engines, comprising the bidirectionally curved, shaped, and variable-diameter tube forming mold and the dual-action liquid-filled stretching device described in Example 1 or Example 2. The inner slider connected to the stretching cylinder of the dual-action liquid-filled stretching device is connected to a combined punch, the outer slider connected to the edge-pressing cylinder of the dual-action liquid-filled stretching device is connected to an upper mold plate, the liquid-filling device of the dual-action liquid-filled stretching device is connected to a liquid-filling port of a sealing pusher, and the inner slider of the liquid-filled device is connected to the combined punch. As the liquid-filling device is raised and lowered, it can drive the combined punch 4 to engage with a combined female mold 1 5, a combined female mold 2 7, a side-pushing female mold 1 6, and a side-pushing female mold 2, thereby forming the profile of the bidirectionally curved, shaped, and variable-diameter tube. The outer slider of the liquid-filled device is connected to an upper mold plate 1, and the liquid-filling device of the liquid-filled device is connected to a liquid-filling port of a sealing pusher 8.

[0031] Example 4 This embodiment provides a method for forming a bidirectionally curved special-shaped variable diameter tube for an aircraft engine, the steps comprising: S1. The tube is placed on a combination of a female mold 5, a combination of the female mold 7, plug the ends of the seal push head 8 into the introduction section 801, the end side of the seal push head 8 is installed in the slider 9 connected to the double-action liquid filling stretching device; S2. The outer slider of the double-action liquid-filled stretch forming machine drives the upper mold plate 1 downward. The binder block 2 presses against both ends of the tube, controlling the upper mold plate 1 to continue its downward movement. The lower inclined surface 1002 of the wedge drive component 10 engages with the upper inclined surface 901 of the slider 9. Under the downward force of the wedge drive component 10, the slider 9 moves horizontally. The flexible sealing segment 802 of the sealing pusher 8 performs the first stage of sealing. The sealing pusher 8 then pushes the support segment 803 and the rigid sealing segment 804 into the tube to complete the second stage of sealing. S3. After the liquid filling device applies a certain amount of hydraulic pressure to the tube, the inner slide of the double-action liquid filling stretch forming device drives the combined punch 4 downward until it engages with the combined female die 5 and the second female die 7, completing the vertical pre-bending of the tube. The side pusher dies 6 and 2 then engage with the combined female die 5 and the second female die 7, completing the horizontal pre-bending of the tube. S4. Control the upper template 1 downward, driving the upper inclined surface 1001 of the inclined wedge transmission component 10 to cooperate with the lower inclined surface 902 of the slider 9. The slider 9 continues to push the feeding section 805 of the sealing pusher 8 to the tube blank. At the same time, according to the loading hydraulic curve, a higher liquid chamber pressure is applied to match the advancement of the sealing pusher 8 to achieve bulging of the special-shaped surface inside the tube.

[0032] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A bidirectional bending special-shaped reducer tube forming die for aircraft engines, characterized in that: It includes an upper mold plate, a lower mold plate, a combined mold, a pressing block, a sealing push head and an inclined wedge transmission component; The combined die includes a combined female die 1, a combined female die 2, a side push female die 1, a side push female die 2 and a combined male die. The combined female die 1 and the combined female die 2 are fixed at intervals on the lower template. The side push female die 1 and the side push female die 2 are slidably connected to the lower template. The side push female die 1 and the side push female die 2 can be combined with the combined female die 1 and the combined female die 2. The combined male die can be combined with the combined female die 1, the combined female die 2, the side push female die 1 and the side push female die 2 to form a profile of a bidirectionally curved special-shaped reducer tube. The upper template is provided with a pressing block for fixing the tube blanks at both ends of the female mold, and the two ports of the tube blank in the combined mold are provided with sealing push heads. The lower template is provided with a sliding slider, one end of the slider is connected to the sealing push head, and the other end is provided with an upper inclined surface 1 and a lower inclined surface 1 with different inclination angles; the upper template is also provided with an inclined wedge transmission component, and the inclined wedge transmission component includes a lower inclined surface 2 that cooperates with the upper inclined surface 1 of the slider, and an upper inclined surface 2 that cooperates with the lower inclined surface 1 of the slider; The sealing pusher head includes an inlet section, a flexible sealing section, a support section, a rigid sealing section and a feeding section which are connected in sequence. The lengths of the flexible sealing section, the support section and the rigid sealing section are the same as the feed stroke of the upper inclined surface 1 of the slider and the lower inclined surface 2 of the inclined wedge transmission component. The length of the feeding section is the same as the feed stroke of the lower inclined surface 1 of the slider and the upper inclined surface 2 of the inclined wedge transmission component. The sealing pusher head is also provided with a liquid filling port for filling liquid into the tube blank.

2. The bidirectional bending special-shaped reducer tube forming die for aircraft engines according to claim 1, characterized in that: The lower template is provided with a slide rail, and the side push female mold 1 and the side push female mold 2 are connected to the lower template through the slide rail.

3. The bidirectional bending special-shaped reducer tube forming die for aircraft engines according to claim 1, characterized in that: The pressing block is connected to the upper template via a spring.

4. The bidirectional bending special-shaped reducer tube forming die for aircraft engines according to claim 1, characterized in that: A liquid filling channel is provided in the sliding block, and the liquid filling channel is connected to the liquid filling port of the sealing push head.

5. The bidirectional bending special-shaped reducer tube forming die for aircraft engines according to claim 1, characterized in that: A groove is provided on the outer periphery of the flexible sealing section, and a rubber sealing ring is provided in the groove.

6. The bidirectional bending special-shaped reducer tube forming die for aircraft engines according to claim 1, characterized in that: The upper inclined surface of the slider has an inclination angle of 45°, and the lower inclined surface of the slider has an inclination angle of 50-60°; the upper inclined surface of the inclined wedge transmission component has an inclination angle of 50-60°, and the lower inclined surface of the inclined wedge transmission component has an inclination angle of 45°.

7. The bidirectional bending special-shaped reducer tube forming die for aircraft engines according to claim 1, characterized in that: Wear-resistant blocks are provided on the upper inclined surface 2 and the lower inclined surface 2 of the wedge transmission component.

8. A bidirectional bending special-shaped reducer tube forming device for aircraft engines, characterized in that: It comprises a bidirectionally bent special-shaped reducer tube forming die for aircraft engines and a double-action liquid filling and stretching forming device as described in any one of claims 1 to 7, wherein the inner slider of the double-action liquid filling and stretching forming device is connected to the combined punch, the outer slider of the double-action liquid filling and stretching forming device is connected to the upper template, and the liquid filling device of the double-action liquid filling and stretching forming device is connected to the liquid filling port of the sealing push head.

9. A method for forming a bidirectionally curved special-shaped reducer tube for an aircraft engine, characterized in that the steps include: S1. Place the tube blank on a combination of a female mold and a combination of two female molds, insert the lead-in section of the sealing push head at both ends, and install a slider connecting the sealing push head end side to the filling device; S2. The upper template is driven downward, with the pressure blocks pressing against both ends of the tube. The upper template is then controlled to continue its downward movement. The lower inclined surface 2 of the wedge drive component contacts the upper inclined surface 1 of the slider. The downward force of the wedge drive component pushes the slider horizontally. The flexible sealing section of the sealing pusher performs the first stage of sealing. The sealing pusher then pushes the supporting and rigid sealing sections into the tube to complete the second stage of sealing. S3. After the tube is filled with liquid and a certain hydraulic pressure is applied, the combined punch is driven downward until it is engaged with the combined female die 1 and the combined female die 2, completing the vertical pre-bending of the tube. The side pusher dies 1 and 2 are then pushed together with the combined female die 1 and the combined female die 2 to complete the horizontal pre-bending of the tube. S4. Control the upper template downward, driving the upper inclined surface 2 of the inclined wedge transmission component to cooperate with the lower inclined surface 1 of the slider. The slider continues to push the feeding section of the sealing pusher to the tube blank. At the same time, according to the loading hydraulic curve, a higher liquid chamber pressure is applied to match the advancement of the sealing pusher, achieving expansion of the special-shaped surface inside the tube.

10. The method for forming a bidirectionally bent special-shaped reducer tube for an aircraft engine according to claim 9, characterized in that: The rigid sealing section is at an inclined angle, and the rigid sealing section feeds and presses the tube blank wall to be thinned to 0.6 to 0.7 times the wall thickness to achieve the second stage of sealing.

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