Initial wave control mechanism and control method, special-shaped pipe fitting hydroforming device and forming method

Abstract

The present invention discloses a primary wave control mechanism and a control method, a special-shaped pipe fitting hydroforming device and a forming method. The primary wave control mechanism includes a metal rod with an end extending into the space between the upper die and the lower die, a positive connection end electrically connected to the metal rod, a negative connection end electrically connected to the lower die, and a peripheral circuit electrically connected to the positive connection end and the negative connection end. The metal rod is assembled on the upper die through a detachable component, and one end of the metal rod is a positioning end corresponding to the position of the primary wave crest. The primary wave control mechanism can accurately control the size of the primary wave, thereby improving the processing accuracy of special-shaped pipe fittings.

Description

Technical Field

[0001] The present invention relates to the technical field of special-shaped pipe fitting processing, in particular to a primary wave control mechanism and control method for a hydraulic forming device of special-shaped pipe fittings, a forming device and a forming method thereof. Background Art

[0002] Hydraulic forming is the main forming method for processing special-shaped pipe fittings. The forming die includes an upper die and a lower die. A forming inner circle for the pipe blank to pass through is formed at the center of the upper die and the lower die. A liquid injection hole is formed at the top of the upper die to inject the forming liquid into the pipe blank. The bottom of the upper die is a forming surface matching the wave crest of the special-shaped pipe. During the forming process, the upper die rises, the pipe blank is placed in the forming inner circle of the upper die and the lower die, the forming liquid is injected into the pipe blank, and a primary wave is formed in the part of the pipe blank between the upper die and the lower die under the action of the liquid pressure. Then the upper die presses down, and the primary wave is reshaped by the forming surface to form a final wave.

[0003] For a pipe blank with uniform wall thickness, the height of the primary wave of the hydraulically formed special-shaped pipe fitting affects the final corrugation height to a certain extent. The usual forming processes and equipment have deficiencies:

[0004] First, the gap between the pipe blank and the inner wall of the die (forming inner circle) is not considered. Since there is a gap between the outer wall of the pipe blank and the forming inner circle before forming, before the primary wave is formed, it first undergoes preliminary expansion so that the outer diameter of the pipe blank fits the forming inner circle. Usually, when calculating the size of the primary wave, it is the distance from the primary wave to the axis of the pipe blank minus the diameter of the pipe blank. In fact, the size of the primary wave is the distance from the primary wave to the axis of the pipe blank minus the diameter of the pipe blank after expansion. Therefore, there is an error in the usually calculated size of the primary wave.

[0005] Second, the device for detecting the height of the primary wave cannot detect it during the processing to control the wave height in a timely manner, and thus cannot meet the requirements of high-precision wave processing. Summary of the Invention

[0006] The purpose of the present invention is to provide a hydraulic forming device for special-shaped pipe fittings to solve the problem of low processing precision of special-shaped pipes in the prior art. By using the contact conduction principle to control the hydraulic pressure to control the primary wave device, and then constraining the corrugation outer diameter through the forming die, the final wave height precision is guaranteed.

[0007] Another purpose of the present invention is to provide a forming method for the forming device, which can effectively improve the processing efficiency and processing precision.

[0008] The technical solutions adopted to achieve the purpose of the present invention are as follows:

[0009] A primary wave control mechanism for hydroforming of special-shaped pipe fittings, comprising a metal rod with its end extending between the upper die and the lower die, a positive connection end electrically connected to the metal rod, a negative connection end electrically connected to the lower die, and a peripheral circuit electrically connected to the positive connection end and the negative connection end, wherein the metal rod is assembled on the upper die through a detachable component, and one end of the metal rod is a positioning end corresponding to the position of the primary wave crest.

[0010] In the above technical solution, the detachable component includes a matrix made of insulating material and a magnetic block fixed on the matrix, and the end of the metal rod is threadedly connected to the matrix.

[0011] In the above technical solution, the detachable component further includes a positioning portion for determining the position of the positioning end, and the positioning portion includes vertical positioning and horizontal positioning.

[0012] In the above technical solution, the vertical positioning is a positioning card angle formed on the matrix, and the positioning card angle cooperates with a flange formed on the upper die for vertical positioning.

[0013] In the above technical solution, the horizontal positioning includes a threaded hole formed on the matrix for assembling the fixed end of the metal rod, and a limit nut for fastening the fixed end on the threaded hole.

[0014] In the above technical solution, the metal rod has an elongated flat-end structure.

[0015] On the other hand of the present invention, a control method for the primary wave control mechanism for hydroforming of special-shaped pipe fittings. The tube blank gradually expands under the action of liquid pressure, and a primary wave is formed during the expansion process. When the outer wall of the primary wave contacts the end position of the metal rod, the peripheral circuit is electrically conducted, the liquid pressure stops rising and remains unchanged, and the primary wave is formed.

[0016] On the other hand of the present invention, a hydroforming device for special-shaped pipe fittings, comprising a hydraulic device, an upper die, a lower die, and the primary wave control mechanism.

[0017] In the above technical solution, the upper die is fixed below the hydraulic device. Forming inner circles for the tube blank to pass through are formed at the centers of both the upper die and the lower die. A sealing gasket is fixed at the bottom of the forming inner circle formed at the center of the lower die. The liquid injection hole on the hydraulic device is communicated with the forming inner circle at the center of the upper die to inject liquid into the tube blank. The bottom of the upper die is a forming surface matching the wave crest of the special-shaped pipe, and the top of the lower die is a forming plane.

[0018] In the above technical solution, the forming surface is a stepped inner circle formed at the bottom of the upper die, and is coaxially arranged with the forming inner circle at the center of the upper die.

[0019] In the above technical solution, the position where the stepped inner circle is adjacent to the formed inner circle at the center of the upper die is a rounded corner or a right angle.

[0020] On the other hand of the present invention, a forming method of the special-shaped pipe fitting hydraulic forming device includes the following steps:

[0021] Step 1: Install the upper die, lower die, pipe blank and initial wave control mechanism in place. Inject liquid into the pipe blank through the upper die, and gradually increase the pressure of the liquid. Under the action of the liquid pressure, the pipe blank expands outwards until it fits against the inner wall of the formed inner circle.

[0022] Step 2: Continue to increase the liquid pressure. The part of the pipe blank without die constraint continues to expand outwards and gradually forms an initial wave. When the outer wall of the initial wave contacts the positioning end of the metal rod, a circuit is formed among the peripheral circuit, metal rod, pipe blank and lower die. After electrical conduction, control the liquid pressure to remain unchanged and stop increasing, and the initial wave is formed.

[0023] Step 3: Remove the initial wave control mechanism. The upper die or the lower die is driven to approach each other. Under the combined action of the liquid, upper die and lower die, the pipe blank expands and deforms outwards until it contacts the forming surface of the upper die.

[0024] Step 4: The upper die and the lower die continue to approach until they fit together. The pipe blank slides and deforms along the forming surface until it contacts the forming surface and the forming plane respectively, forming corrugations, and the forming is completed.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. At the moment when the initial wave contacts the metal rod in the present invention, direct current is conducted, and the switch controls the liquid pressure to remain unchanged, ensuring the height accuracy of the initial wave. Then, by constraining the outer diameter of the special-shaped pipe with the forming die, the high accuracy of the final wave is well ensured.

[0027] 2. The initial wave control mechanism is detachably assembled on the die, which is convenient for disassembly and assembly, can effectively improve the processing efficiency. The initial wave control mechanism can achieve precise positioning through positioning in two vertical and horizontal directions, and can effectively improve the processing accuracy.

[0028] 3. The initial wave control mechanism of the present invention can be assembled on the basis of the existing die. Without purchasing new processing dies, the control of the initial wave size can be realized, reducing the processing cost. Description of the Drawings

[0029] Figure 1 is a structural schematic diagram of the special-shaped pipe fitting hydraulic forming device;

[0030] Figure 2 is Figure 1 a partial enlarged view of;

[0031] Figure 3 Schematic structural diagram of the tube blank closely adhering to the formed inner circle;

[0032] Figure 4 is Figure 3 partial enlarged view of;

[0033] Figure 5 Schematic diagram of forming the initial wave.

[0034] Figure 6 Schematic diagram of using the mold to limit the height of the initial wave.

[0035] Figure 7 Schematic diagram of the final forming.

[0036] In the figure: 1 - upper die, 2 - lower die, 3 - metal rod, 4 - positive electrode connection end, 5 - negative electrode connection end, 6 - tube blank, 7 - base body, 8 - magnetic block, 9 - threaded hole, 10 - limit nut, 11 - positioning corner, 12 - hydraulic equipment, 13 - formed inner circle, 14 - positioning end, 15 - liquid, 16 - gasket, 17 - forming plane, 18 - forming surface Specific embodiments

[0037] The present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] Embodiment 1

[0039] An initial wave control mechanism for hydroforming of special-shaped pipe fittings includes a metal rod 3 with its end extending into the space between the upper die 1 and the lower die 2, a positive electrode connection end 4 electrically connected to the metal rod 3, a negative electrode connection end 5 electrically connected to the lower die 2, and a peripheral circuit electrically connected to the positive electrode connection end 4 and the negative electrode connection end 5. The metal rod 3 is assembled on the upper die 1 through a detachable component, and one end of the metal rod 3 is a positioning end 14 corresponding to the peak position of the initial wave.

[0040] The positive electrode connection end 4 and the negative electrode connection end 5 can be a positive electrode wire and a negative electrode wire respectively. When in use:

[0041] Install the upper die 1, the lower die 2, the tube blank 6 and the initial wave control mechanism in place. Inject the liquid 15 into the tube blank 6 through the upper die 1, and gradually increase the pressure of the liquid 15. The tube blank 6 is subjected to the pressure of the liquid 15 and expands outward to fit against the inner wall of the formed inner circle 13, as shown in Figure 3 and 4 shown.

[0042] Continue to increase the pressure of the liquid 15. The part of the tube blank 6 without die constraint (the part between the upper die 1 and the lower die 2) continues to expand outwards. When the outer wall of the initial wave contacts the end position of the metal rod 3, the peripheral circuit, the metal rod 3, the tube blank 6, and the lower die 2 form a circuit. After the electrical conduction, the control switch on the hydraulic device 12 disconnects, the pressure of the liquid 15 stops increasing and remains unchanged, and the initial wave is formed.

[0043] Embodiment 2

[0044] For more convenient disassembly, this embodiment further describes the structure of the detachable component.

[0045] The detachable component includes a base body 7 made of insulating material and a magnetic block 8 fixed on the base body 7. A threaded hole 9 for assembling the metal rod 3 is formed on the base body 7. When installing the control mechanism, the magnetic block 8 (a strong magnetic magnet can be used) adsorbs the upper die 1, so that the base body 7 is fixed together on the outer circle of the upper die 1. The base body 7 made of insulating material can be a base body 7 made of plastic material. When disassembling, pull the base body 7 outwards, and the magnetic block 8 is separated from the upper die 1 to complete the disassembly.

[0046] As a preferred method, the detachable component further includes a positioning part, and the positioning part includes vertical positioning and horizontal positioning. Through the positioning in two directions of the vertical direction and the horizontal direction, the accurate positioning of the positioning end 14 is realized.

[0047] As a preferred method, the vertical positioning includes a positioning card angle 11 formed on the base body 7, and the positioning card angle 11 cooperates with a flange formed on the upper die 1 for vertical positioning. The positioning card angle 11 includes a horizontal plane and a vertical plane, and the flange includes an upper plane and a side wall surface. When positioning, the horizontal plane fits with the upper plane, and the vertical plane fits with the side wall surface to complete the positioning in the vertical direction.

[0048] As a preferred method, the horizontal positioning includes a threaded hole 9 formed on the base body 7 for the fixed end of the metal rod 3 to pass through, and a limit nut 10 for fixing the fixed end of the metal rod 3 on the threaded hole 9.

[0049] Rotate the metal rod 3 to move it left and right, and horizontal adjustment can be performed. After reaching the preset position, use the limit nut 10 to tighten the metal rod 3 for positioning. There are two limit nuts 10, which position the metal rod 3 from the left and right sides of the base body 7 respectively.

[0050] In summary, the positioning part can accurately determine the position of the positioning end 14 of the metal rod 3. Clamp the positioning card angle 11 on the flange, and at the same time, the magnetic block 8 adsorbs on the upper die 1, which can determine the position of the positioning end 14 of the metal rod 3 in the vertical direction. By rotating the limit nut 10, the position of the positioning end 14 of the metal rod 3 in the horizontal direction can be adjusted.

[0051] As a preferred embodiment, the metal rod 3 has an elongated flat end structure, which is convenient for positioning.

[0052] Embodiment 3

[0053] A special-shaped pipe fitting hydroforming device includes a hydraulic device 12, an upper die 1, a lower die 2, and the initial wave control mechanism as described in Embodiment 1. The initial wave control mechanism is applied to the existing special-shaped pipe fitting hydroforming device, and auxiliary control of the initial wave can be carried out without other modifications to the forming device.

[0054] As a preferred embodiment, the upper die 1 is fixed below the hydraulic device 12. Forming inner circles 13 for the pipe blank 6 to pass through are formed at the centers of both the upper die 1 and the lower die 2. A sealing gasket 16 is fixed to the bottom of the forming inner circle 13 formed at the center of the lower die 2. The liquid injection hole on the hydraulic device 12 is connected to the forming inner circle 13 at the center of the upper die 1 to inject the forming liquid 15 into the pipe blank 6. The bottom of the upper die 1 is a forming surface 18 matching the wave crest of the special-shaped pipe, and the top of the lower die 2 is a forming plane 17.

[0055] The forming inner circles 13 at the centers of the upper die 1 and the lower die 2 are coaxially arranged and have the same inner diameter, and the inner diameter of the forming inner circle 13 is slightly larger than the outer diameter of the pipe blank. The sealing gasket 16 is used to seal the liquid filled in the pipe blank 6 to prevent the liquid from leaking from the bottom of the pipe blank 6.

[0056] The forming method of the special-shaped pipe fitting hydroforming device includes the following steps:

[0057] Step 1: Install the upper die 1, the lower die 2, the pipe blank 6, and the initial wave control mechanism in place. Inject the liquid 15 into the pipe blank 6 through the upper die 1, and gradually increase the pressure of the liquid 15. The pipe blank 6 is subjected to the pressure of the liquid 15 and expands outward to fit against the inner wall of the forming inner circle 13, as shown in Figure 3 and 4 shown.

[0058] Step 2: Continue to increase the pressure of the liquid 15. The unconstrained part of the pipe blank 6 (the part between the upper die 1 and the lower die 2) continues to expand outward. When the outer wall of the initial wave contacts the end position of the metal rod 3, a circuit is formed among the peripheral circuit, the metal rod 3, the pipe blank 6, and the lower die 2. After electrical conduction, the control switch on the hydraulic device 12 disconnects, and the pressure of the liquid 15 stops rising, and the initial wave is formed.

[0059] Step 3: Remove the initial wave control mechanism. The upper die 1 or the lower die 2 is driven to move closer to each other. The pipe blank 6 is subjected to the combined action of the liquid 15, the upper die 1, and the lower die 2, and expands and deforms outward until it contacts the forming surface 18 of the upper die 1, as shown in Figure 6 shown.

[0060] Step 4: The upper die 1 and the lower die 2 continue to move closer until they are in contact. The tube blank 6 slides and deforms along the forming surface 18 until it contacts the forming surface 18 and the forming plane 17 respectively, forming corrugations, and the forming is completed.

[0061] Before forming, lubricating oil can be coated on the forming surface 18, and a thin plastic film adheres to the lubricating oil to play a lubricating role.

[0062] As a preferred method, the forming surface 18 is a stepped inner circle formed at the bottom of the upper die 1, and is coaxially arranged with the forming inner circle 13 at the center of the upper die 1. The forming surface 18 and the forming plane 17 cooperate with each other to extrude and form the corrugations of the special-shaped tube.

[0063] As a preferred method, the position where the stepped inner circle is adjacent to the forming inner circle 13 at the center of the upper die 1 is a rounded corner or a right angle. The size of the stepped inner circle is equivalent to the size of the final wave of the special-shaped tube.

[0064] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An initial wave control mechanism for hydroforming of special-shaped pipe fittings, characterized in that The device comprises a metal rod with an end extending between the upper mold and the lower mold, a positive electrode connection end electrically connected to the metal rod, a negative electrode connection end electrically connected to the lower mold, and a peripheral circuit electrically connected to the positive electrode connection end and the negative electrode connection end, wherein the metal rod is assembled on the upper mold through a detachable component, and one end of the metal rod is a positioning end corresponding to the peak position of the primary wave; The detachable component includes a base body made of an insulating material and a magnetic block fixed on the base body, and the end of the metal rod is threadedly connected to the base body; The detachable assembly further comprises a positioning portion for determining the position of the positioning end, wherein the positioning portion includes vertical positioning and horizontal positioning; The metal rod is a slender flat-end structure.

2. The initial wave control mechanism for hydroforming of special-shaped pipe fittings according to claim 1, wherein, The vertical positioning is a positioning angle formed on the base, and the positioning angle cooperates with a flange formed on the upper mold to perform vertical positioning.

3. The initial wave control mechanism for hydroforming of special-shaped pipe fittings as described in claim 1, characterized in that The horizontal positioning includes a threaded hole formed on the base for assembling the fixed end of the metal rod, and a limiting nut for fastening the fixed end to the threaded hole.

4. The control method of the primary wave control mechanism for hydroforming of special-shaped pipe fittings according to any one of claims 1-2, characterized in that, The tube blank gradually expands under the action of liquid pressure, and the primary wave is formed during the expansion process. When the outer wall of the primary wave contacts the end of the metal rod, the peripheral circuit is electrically conductive, the liquid pressure stops increasing and remains unchanged, and the primary wave is formed.

5. A special-shaped pipe fitting hydraulic forming device, characterized in that, The invention comprises a hydraulic device, an upper die, a lower die and an initial wave control mechanism as claimed in any one of claims 1 to 3.

6. The special-shaped pipe fitting hydroforming device according to claim 5, wherein, The upper die is fixed below the hydraulic equipment. The centers of the upper die and the lower die are both formed with forming inner circles for the tube blank to pass through, wherein a sealing gasket is fixed to the bottom of the forming inner circle formed in the center of the lower die. The liquid injection hole on the hydraulic equipment is connected to the forming inner circle in the center of the upper die to inject liquid into the tube blank. The bottom of the upper die is a forming surface that matches the wave crest of the special-shaped tube, and the top of the lower die is a forming plane.

7. The special-shaped pipe fitting hydraulic forming device according to claim 6, wherein, The forming surface is a stepped inner circle formed at the bottom of the upper mold and is coaxially arranged with the forming inner circle at the center of the upper mold.

8. The special-shaped pipe fitting hydroforming device according to claim 7, wherein, The position where the stepped inner circle is adjacent to the forming inner circle at the center of the upper mold is a rounded angle or a right angle.

9. The forming method of the special-shaped pipe fitting hydraulic forming device according to any one of claims 6-8, characterized in that, The following steps are involved: Step 1: Install the upper die, lower die, tube blank, and initial wave control mechanism in place, inject liquid into the tube blank through the upper die, and gradually increase the pressure of the liquid. The tube blank is affected by the liquid pressure and expands outward until it fits the inner wall of the forming inner circle. Step 2: Continue to increase the liquid pressure. The portion of the tube that is not constrained by the mold continues to expand outward, gradually forming a primary wave. When the outer wall of the primary wave contacts the positioning end of the metal rod, a path is formed between the peripheral circuit, the metal rod, the tube, and the lower mold. After electrical conduction, the liquid pressure is controlled to remain unchanged and stop increasing, and the primary wave is formed. Step 3: The primary wave control mechanism is disassembled, and the upper die or the lower die is driven to approach each other. The tube blank is affected by the liquid, the upper die, and the lower die, and expands and deforms outward until it contacts the forming surface of the upper die. Step 4: The upper die and the lower die continue to approach until they fit together, and the tube blank slides and deforms along the forming surface until it contacts the forming surface and the forming plane respectively, forming corrugations, and the forming is completed.

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