An adjustable liquid-filled push bending die for manufacturing a large aspect ratio tube set

Abstract

This invention discloses an adjustable fluid-filling push-bending mold for manufacturing large-diameter-thickness ratio pipe assemblies. It includes a lower mold base, a lower core mold, an upper core mold, an upper mold base, a pusher assembly, and a plug assembly connected in sequence. The upper mold base is connected to a guide sleeve, and the lower mold base is connected to a guide post. The guide sleeve can be fitted onto the upper part of the guide post through a central hole and can slide relative to the guide post. A contact plate is provided between the upper and lower mold bases, and the contact plate is connected to both the upper and lower mold bases respectively. The pusher assembly and the plug assembly are respectively located at both ends of the pipe blank. This invention allows control of the orifice size through an orifice adjustment device, thereby adjusting the flow rate and, consequently, the internal and external pressure difference of the pipe blank. It can complete the forming of different pipe fittings, effectively reducing costs, improving work efficiency, and realizing the manufacturing of large-diameter-thickness ratio pipe assemblies.

Description

Technical Field

[0001] This invention belongs to the field of equipment manufacturing technology and relates to an adjustable fluid-filling push-bending mold for manufacturing large diameter-to-thickness pipe assemblies. Background Technology

[0002] Large diameter-to-thickness ratio elbows are widely used in aerospace, shipbuilding, and nuclear industries, and are an important component of the piping systems of launch vehicles and large aircraft. These parts typically have a diameter-to-thickness ratio of over 60, a diameter of 90-300 mm, and a wall thickness of 1-2.5 mm. Traditional forming methods involve welding half of the tube together; however, this method results in poor forming quality and low forming efficiency, and the presence of weld seams reduces the strength of the part. With the trend towards lightweight and integrated designs in aerospace products, the demand for integrally formed large diameter-to-thickness ratio elbow parts is becoming increasingly prominent.

[0003] Currently, solutions mainly rely on additive manufacturing and cold extrusion. However, additive manufacturing consumes a lot of materials, has difficulties in bending and supporting the tubes during the printing process, has low production efficiency and high costs, and is unlikely to improve part performance. Cold extrusion requires multiple forming processes, resulting in low efficiency, difficulty in controlling the parameters of thin-walled extrusion, numerous influencing factors, and a high failure rate. Therefore, there is a need to propose a highly efficient forming method that can both ensure part forming quality and improve part performance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies, such as high cost, high failure rate, and poor mechanical properties of formed pipe parts, and to provide an adjustable liquid-filled push-bending mold for manufacturing large diameter-to-thickness ratio pipe assemblies. By using a pipe sealing device, upper and lower molds, and replaceable mold cores to form a complete set of equipment, high-pressure liquid is filled into the pipe for flexible manufacturing, completing the forming of large diameter-to-thickness ratio elbow parts with different bending radii. This can effectively reduce costs and realize the manufacturing of large diameter-to-thickness ratio elbow parts with different bending radii.

[0005] To achieve the above objectives, the present invention employs the following technical solutions:

[0006] An adjustable fluid-filled push-bending die for manufacturing large diameter-to-thickness pipe assemblies includes a lower die base, a lower core die, an upper core die, an upper die base, a pusher assembly, and a plug assembly connected in sequence. The upper die base is connected to a guide sleeve, and the lower die base is connected to a guide post. The guide sleeve can be sleeved on the upper part of the guide post through a central hole and can slide relative to the guide post. A contact plate is provided between the upper die base and the lower die base, and the contact plate is connected to the upper die base and the lower die base respectively. The pusher assembly and the plug assembly are respectively provided at both ends of the pipe blank.

[0007] The pusher assembly includes a first push tube, a locking nut, an outer end cap, a large sealing gasket, a wedge-shaped sealing ring, an inner end cap, a pull rod, and a small sealing gasket connected in sequence.

[0008] The plug assembly includes a second push tube and a plug, which are connected by screws.

[0009] As a preferred embodiment, the outer end cap of the first push tube is connected by screws.

[0010] As a preferred embodiment, the outer cylindrical surface of the outer end cap is provided with an annular groove, and an O-ring is provided in the groove.

[0011] As a preferred embodiment, the outer cylindrical surface of the plug is provided with an annular groove, and an O-ring is provided in the groove.

[0012] As a preferred embodiment, the tie rod is provided with a T-shaped step, with the step near the step being a smooth column and the step away from the step being threaded.

[0013] In a further preferred embodiment, the small sealing gasket has a hole in the middle, and is fitted onto the pull rod through the hole, fitting snugly against the T-shaped step of the pull rod.

[0014] As a preferred embodiment, the outer edge of the inner end cap is provided with a bevel, and the inner end cap has a hole in the middle, through which it is fitted onto the pull rod, and the side of the inner end cap without the bevel is in close contact with the small sealing gasket.

[0015] In a further preferred embodiment, the wedge-shaped sealing ring has a hole in the middle, and is fitted onto the outer edge of the inner end cap through the middle hole, fitting against the inclined surface of the inner end cap.

[0016] As a preferred embodiment, the inner side of the outer end cap is provided with a protrusion, the inner edge is provided with a bevel, and the outer side is provided with a groove; the outer end cap has a hole in the middle, through which it is fitted onto the pull rod, and the inner edge bevel is fitted with the wedge-shaped sealing ring.

[0017] In a further preferred embodiment, the locking nut is connected to the pull rod via the thread of the pull rod, and the end face of the locking nut fits into the groove on the outer side of the outer end cap. By screwing in the thread, the outer end cap, the large sealing gasket, the wedge-shaped sealing ring, the inner end cap, and the small sealing gasket are tightened.

[0018] As a preferred embodiment, the flow channel includes a flow channel hole, an aperture adjustment device, and a liquid buffer tank. The flow channel hole is located in the inner cavity of the upper core mold. The liquid buffer tank is surrounded by a sealing groove with sealing rubber. The liquid buffer tank includes an upper liquid buffer tank and a lower liquid buffer tank. The upper liquid buffer tank is located at the contact position between the upper core mold and the upper mold base, and the lower liquid buffer tank is located at the contact position between the lower core mold and the lower mold base. The aperture adjustment device is located at the outlet of the flow channel hole and the upper liquid buffer tank in the upper core mold, and can be an adjustable aperture plug installed on the flow channel hole.

[0019] High-pressure liquid is injected into the inner cavity of the tube blank, entering the mold cavity through the open end of the tube blank. The high-pressure liquid flows into the liquid buffer tank through the flow channel holes in the mold cavity, and then flows out through the small holes on the side wall of the liquid buffer tank. The high-pressure liquid entering the inner cavity of the tube blank creates high pressure. The orifice size can be controlled by an orifice adjustment device, thereby regulating the flow rate and, consequently, the pressure difference between the inside and outside of the tube blank. Specifically, when the orifice size decreases, less liquid passes through per unit time, and the pressure difference between the inside and outside increases, to accommodate different tube blanks.

[0020] When high-pressure liquid flows from the inner cavity of the tube blank to the liquid buffer tank through the flow channel orifice, a pressure loss occurs. Therefore, the pressure in the liquid buffer tank is lower than the pressure inside the tube blank, and consequently, the pressure near the flow channel orifice in the mold cavity is lower than the pressure inside the tube blank. This creates a pressure difference between the inside and outside of the tube blank, holding it tightly against the inner wall of the mold cavity and providing support. Changes in the orifice size affect the magnitude of this pressure difference, which can be controlled by adjusting the orifice size.

[0021] The push-bending forming mold mainly includes upper and lower molds, replaceable mold cores and other components. These components constitute the main body of the mold. The push head, plug and other components together with the tube blank form the liquid filling part. High pressure liquid is filled into the inside of the pipe to flexibly bend the pipe. The forming effect is good, the success rate is high, and it can effectively reduce costs, improve work efficiency and realize the forming of pipe groups with different bending radii and large diameter-to-thickness ratios.

[0022] This invention enables the manufacture of pipe assemblies with different shapes and diameter-to-thickness ratios by replacing mandrels with different bending radii and diameters. The pusher assembly, plug assembly, and pipe blank constitute the liquid-filling section, which fills the pipe with high-pressure liquid for flexible bending. During the liquid-filling process, the internal pressure of the pipe blank increases, causing the pipe wall to conform to the inner cavity of the mold during forming, achieving a supporting effect. The liquid-discharging function works in conjunction with the liquid-filling process to adjust or maintain the internal pressure of the pipe blank, thereby correcting the shape of the pipe blank through greater internal pressure and improving the forming success rate. It is low-cost, has a high success rate, and produces pipes with good mechanical properties after forming, enabling the manufacture of pipe assemblies with different bending radii and large diameter-to-thickness ratios.

[0023] This invention requires less material and has lower costs, requiring only a standard tube blank for molding. It boasts a high success rate, achieving one-time molding, and allows for different wall thicknesses by adjusting the internal pressure. The integrated molding process results in well-mechanically robust large-diameter-thickness ratio bends. Traditional liquid-filled push-bending methods can only form single-bending-radius pipes. When producing large-diameter-thickness ratio pipes with different bending radii or diameters, a complete set of molds needs to be fabricated, leading to higher costs. In contrast, the liquid-filled push-bending mold involved in this invention can complete the molding of different pipes simply by replacing the mold core, effectively reducing costs, improving work efficiency, and enabling the manufacturing of large-diameter-thickness ratio pipe assemblies.

[0024] The present invention has the following advantages:

[0025] 1) This invention employs a modular design approach, enabling the manufacture of pipe assemblies with different shapes and diameter-to-thickness ratios by designing and using mold cores with different bending radii and diameters. This invention reduces mold manufacturing costs and shortens manufacturing time, enabling the molding of various pipe assemblies.

[0026] 2) The bent pipe manufactured by this invention has superior performance. During the forming process, the wall thickness of the pipe blank is changed by adjusting the high-pressure liquid pressure inside the pipe blank, and this process does not damage the pipe blank. This invention can achieve one-piece pipe forming without weld seams and has good mechanical properties.

[0027] 3) This invention has a low cost. During the molding and filling process, the internal pressure of the tube blank increases, causing the tube wall to fit snugly against the mold cavity, achieving a supporting effect. The liquid discharge function, used in conjunction with the filling function, regulates or maintains the internal pressure of the tube blank, allowing for shape correction through higher internal pressure, thus improving the molding success rate and achieving one-time molding. Its widespread application in production can significantly reduce molding time, improve efficiency, and thereby lower costs. Attached Figure Description

[0028] Figure 1 Schematic diagram of the structure of this invention;

[0029] Figure 2 Schematic diagram of the pusher assembly structure of this invention;

[0030] Figure 3 A schematic diagram of the plug assembly structure of this invention.

[0031] In the diagram: 1-lower mold base, 2-lower core mold, 3-upper core mold, 4-upper mold base, 5-guide sleeve, 6-guide post, 7-contact plate, 8-push head assembly, 9-plug assembly, 10-first push tube, 11-O-ring seal, 12-screw, 13-lock nut, 14-outer end cap, 15-large sealing gasket, 16-wedge seal, 17-inner end cap, 18-pull rod, 19-small sealing gasket, 20-plug, 21-second push tube. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings.

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0034] Example:

[0035] An adjustable fluid-filled push-bending die for manufacturing large diameter-to-thickness pipe assemblies includes a lower die base 1, a lower core die 2, an upper core die 3, an upper die base 4, a guide sleeve 5, a guide post 6, a contact plate 7, a push head assembly 8, and a plug assembly 9. The push head assembly 8 includes: a first push tube 10, a locking nut 13, an outer end cap 14, a large sealing gasket 15, a wedge-shaped sealing ring 16, an inner end cap 17, a pull rod 18, and a small sealing gasket 19; the plug assembly 9 includes: a second push tube 21 and a plug 20.

[0036] The lower core mold 2 is connected to the lower mold base 1 by screws, and the lower core mold 2 can be disassembled and replaced; the upper core mold 3 is connected to the upper mold base 4 by screws, and the upper core mold 3 can be disassembled and replaced.

[0037] After the lower core mold 2 and the upper core mold 3 are closed, a complete mold cavity is formed. By replacing the lower core mold 2 and the upper core mold 3 with different bending radii and diameters, pipe assemblies with different shapes and diameter-to-thickness ratios can be manufactured.

[0038] The guide sleeve 5 is connected to the upper mold base 4, and the connection method includes interference fit or screw connection;

[0039] The guide post 6 is connected to the lower mold base 1, and the connection method includes interference fit or screw connection; the guide sleeve 5 can be sleeved on the upper part of the guide post 6 through the middle hole and can slide, playing a mold closing guide role;

[0040] The contact plate 7 is connected to the lower mold base 1 and the upper mold base 4 respectively by screws;

[0041] The tie rod 18 is provided with a T-shaped step, which is smooth and cylindrical near the platform and threaded away from the platform. The tie rod 18 is hollow and can be connected to the injection port at the stepless end of the tie rod 18. Liquid is filled through the through hole in the middle of the tie rod 18. During the filling process, the internal pressure of the tube blank cavity increases, which makes the tube wall fit into the inner cavity of the mold during the molding process, thus achieving a support effect.

[0042] The small sealing gasket 19 has a hole in the middle, and is fitted onto the pull rod 18 through the hole, with one side tightly against the step of the pull rod 18;

[0043] The outer edge of the inner end cap 17 is provided with a bevel, which is fitted onto the pull rod 18 through the middle hole, and the side without the bevel is in close contact with the small sealing gasket 19.

[0044] The large sealing gasket 15 is fitted onto the pull rod 18 through the middle hole, with one side tightly attached to the inner end cap 17;

[0045] The wedge-shaped sealing ring 16 is fitted onto the outer edge of the inner end cap 17 through the central hole and fits against the inclined surface of the inner end cap 17;

[0046] The outer end cap 14 has a protrusion on its inner side, a bevel on its inner edge, a groove on its outer side, and a smooth annular groove on its outer cylindrical surface. The outer end cap 14 is fitted onto the pull rod 18 through the middle hole, and the bevel on its inner outer edge fits against the wedge-shaped sealing ring 16.

[0047] The outer cylindrical surface of the outer end cap 14 has a smooth annular groove with an O-ring seal 11 that fits tightly into the groove.

[0048] The locking nut 13 is connected to the pull rod 18 via the thread on the pull rod 18, and its end face fits into the groove on the outer side of the outer end cap 14. By screwing in the thread, the outer end cap 14, the large sealing gasket 15, the wedge-shaped sealing ring 16, the inner end cap 17, and the small sealing gasket 19 are tightened.

[0049] The first push tube 10 is connected to the outer end cap 14 by screws 12, and the connection method is screw connection, chuck, pin connection or adhesive bonding.

[0050] The plug 20 has three annular grooves on its outer cylindrical surface. The grooves are smooth. The O-ring 11 is fitted into the smooth annular grooves on the outer cylindrical surface of the plug 20 and fits tightly with the grooves.

[0051] One end of the plug 20 is provided with a smooth conical surface, and a through hole is provided at the center of rotation. The end of the plug 20 without a conical surface can be connected to the liquid outlet, and liquid can be released through the through hole in the middle of the plug 20. The liquid release function is used in conjunction with the liquid filling to adjust or maintain the internal pressure of the tube blank, so as to play a role in correcting the shape of the tube blank through a larger internal pressure and improving the molding success rate.

[0052] The second push tube 21 and the plug 20 are connected by screws 12, and the connection method is screw connection, chuck, pin connection or adhesive bonding;

[0053] The end cap of the pusher mechanism 8 is placed inside the tube blank end and is connected to the tube blank. It is located at the front end of the mold cavity. The pusher mechanism provides thrust to the push tube 10 in the pusher 8 through the actuator, which pushes the tube blank to move along the inner wall of the mold cavity. The actuator is a hydraulic cylinder.

[0054] The plugging mechanism 9 is located at the end of the mold cavity. The second push tube 21 is connected to the actuator, which is a hydraulic cylinder. When the tube blank is pushed to the end of the mold cavity, it is guided by the conical surface at the front end of the plugging mechanism 9 and slides onto the plugging mechanism 9 to play a guiding and sealing role.

[0055] The workflow of this embodiment is as follows:

[0056] During the liquid filling and bending process, the mold remains stationary. The end cap of the pusher mechanism 8 is placed inside the tube blank end and is connected to the tube blank by friction through the outer edge of the wedge-shaped sealing ring 16. The injection port is connected to the pull rod 18. After connection, the pusher mechanism 8 and the tube blank are placed at the front end of the straight section of the mold cavity, and the plug mechanism 9 is placed at the end of the mold cavity. The liquid outlet is connected to the plug mechanism 9. Liquid is filled through the through hole in the middle of the pull rod 18. At the same time, the actuator provides thrust to the first push tube 10 in the pusher mechanism 8, causing the tube blank to move along the inner wall of the mold cavity until it passes through the bending section and extends a certain distance, contacting the conical surface at the front end of the plug mechanism 9. Under the guidance of the conical surface, the tube blank slides onto the plug mechanism 9. At this time, the liquid injection pressure is increased to expand the tube blank and ensure the tube blank forming effect.

[0057] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. An adjustable fluid-filling push-bending die for manufacturing large-diameter-to-thickness pipe assemblies, characterized in that, The assembly includes a lower mold base, a lower core mold, an upper core mold, an upper mold base, a pusher assembly, and a plug assembly connected in sequence. The upper mold base is connected to a guide sleeve, and the lower mold base is connected to a guide post. The guide sleeve can be fitted onto the upper part of the guide post through a central hole and can slide relative to the guide post. A contact plate is provided between the upper mold base and the lower mold base, and the contact plate is connected to the upper mold base and the lower mold base respectively. The pusher assembly and the plug assembly are respectively located at both ends of the tube blank. The pusher assembly includes a first push tube, a locking nut, an outer end cap, a large sealing gasket, a wedge-shaped sealing ring, an inner end cap, a pull rod, and a small sealing gasket connected in sequence. The pull rod has a T-shaped step, which is smooth and cylindrical near the stage and threaded away from the stage. The pull rod is hollow and has a through hole in the middle. The end of the pull rod without the step is connected to the injection port, and liquid enters through the through hole in the middle of the pull rod. The filling process involves filling the mold with liquid. The plug assembly includes a second push tube and a plug, which are connected by screws. One end of the plug has a smooth conical surface, and the center of rotation has a through hole. The non-conical end of the plug is connected to the outlet, and liquid is released through the through hole in the middle of the plug. The upper core mold has a flow channel, which includes a flow channel hole, an aperture adjustment device, and a liquid buffer tank. The flow channel hole is located in the inner cavity of the upper core mold. The liquid buffer tank has a sealing groove around its perimeter, and sealing rubber is installed inside the sealing groove. The liquid buffer tank includes an upper liquid buffer tank and a lower liquid buffer tank. The upper liquid buffer tank is located at the contact position between the upper core mold and the upper mold base, and the lower liquid buffer tank is located at the contact position between the lower core mold and the lower mold base. The aperture adjustment device is located at the outlet of the flow channel hole and the upper liquid buffer tank in the upper core mold.

2. The adjustable fluid-filling push-bending die for manufacturing large-diameter-to-thickness pipe assemblies according to claim 1, characterized in that: The first push tube is connected to the outer end cap by screws.

3. The adjustable fluid-filling push-bending die for manufacturing large-diameter-to-thickness pipe assemblies according to claim 1, characterized in that: The outer cylindrical surface of the outer end cap is provided with an annular groove, and an O-ring is provided in the groove.

4. The adjustable fluid-filling push-bending die for manufacturing large-diameter-to-thickness pipe assemblies according to claim 1, characterized in that: The outer cylindrical surface of the plug is provided with an annular groove, and an O-ring is provided in the groove.

5. The adjustable fluid-filling push-bending die for manufacturing large-diameter-to-thickness pipe assemblies according to claim 1, characterized in that: The small sealing gasket has a hole in the middle, and is fitted onto the pull rod through the hole, fitting snugly against the T-shaped step of the pull rod.

6. The adjustable fluid-filling push-bending die for manufacturing large-diameter-to-thickness pipe assemblies according to claim 1, characterized in that: The outer edge of the inner end cap is provided with a bevel, and the middle of the inner end cap is provided with a hole. It is fitted onto the pull rod through the middle hole, and the side of the inner end cap without the bevel is in close contact with the small sealing gasket.

7. The adjustable fluid-filling push-bending die for manufacturing large-diameter-to-thickness pipe assemblies according to claim 6, characterized in that: The wedge-shaped sealing ring has a hole in the middle, and is fitted onto the outer edge of the inner end cap through the middle hole, fitting against the inclined surface of the inner end cap.

8. The adjustable fluid-filling push-bending die for manufacturing large-diameter-to-thickness pipe assemblies according to claim 1, characterized in that: The outer end cap has a protrusion on its inner side, a bevel on its inner edge, and a groove on its outer side; the outer end cap has a hole in the middle, through which it is fitted onto the pull rod, and the bevel on its inner edge fits into the wedge-shaped sealing ring.

9. The adjustable fluid-filling push-bending die for manufacturing large-diameter-to-thickness pipe assemblies according to claim 8, characterized in that: The locking nut is connected to the pull rod via the thread of the pull rod. The end face of the locking nut fits into the groove on the outer side of the outer end cap. By screwing it in through the thread, the outer end cap, large sealing gasket, wedge-shaped sealing ring, inner end cap, and small sealing gasket are tightened.

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