Molding device

Abstract

The molding device is provided with: a fluid supply unit which is disposed at the end of the metal pipe material and supplies a fluid to the inside of the metal pipe material through an opening in the end; and a sealing mechanism that seals against leakage of the fluid from the metal tube material when the fluid is supplied by the fluid supply unit to the metal tube material heated by the heating unit, the sealing mechanism sealing without applying an axial force to the metal tube material by contacting the metal tube material with a non-resin material.

Description

Technical Field

[0001] The invention relates to a forming device. Background Art

[0002] Conventionally, there are known expansion molding devices for expansion molding metal tube materials. For example, the expansion molding device disclosed in Patent Document 1 below performs expansion molding by heating the metal tube material, pressing a nozzle against the metal tube material to seal it, and supplying a high-pressure fluid from the nozzle.

[0003] Previous technical literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2019-163190 Summary of the Invention

[0006] Technical issues to be solved by the invention

[0007] Here, the expansion molding device seals with a resin material and supplies fluid. However, if the temperature near the end of the metal tube material also reaches a high temperature (for example, when the metal tube material is heated in a furnace), there is a problem that the resin material may be damaged during the sealing.

[0008] Therefore, an object of the present invention is to provide a forming device for an expansion forming device, which can perform sealing while suppressing the influence of a high-temperature metal tube material.

[0009] Means for solving technical problems

[0010] A molding device according to one embodiment of the present disclosure includes: a fluid supply portion, which is arranged at an end portion of a metal tube material and supplies a fluid into the interior of the metal tube material through an opening in the end portion; and a sealing mechanism, which, when the fluid is supplied by the fluid supply portion to the metal tube material heated by the heating portion, seals against leakage of the fluid from the metal tube material. The sealing mechanism seals the metal tube material without applying an axial force to the metal tube material by contacting the metal tube material with a non-resin material.

[0011] The molding device is equipped with a sealing mechanism that seals against leakage of the fluid from the metal tube material when the fluid is supplied from the fluid supply portion to the metal tube material heated by the heating portion. Therefore, the fluid supplied from the fluid supply portion to the interior of the metal tube material is suppressed from leaking to the outside of the metal tube material by the sealing of the sealing mechanism. Here, the sealing mechanism seals the metal tube material without applying axial force to the metal tube material by contacting the metal tube material with a non-resin material. Thus, a non-resin material having a higher heat resistance than a sealing component such as a resin O-ring can be selected as the material of the sealing mechanism. Thus, sealing can be performed while suppressing the influence of the high-temperature metal tube material.

[0012] The fluid supply unit is disposed within the metal tube, and the sealing mechanism is disposed at at least one of the interior and exterior of the metal tube. When the fluid is supplied by the fluid supply unit, the sealing mechanism can move a sealing surface radially toward the metal tube to seal the tube. In this case, because the sealing mechanism can press the sealing surface radially against the metal tube, leakage of the fluid from the metal tube can be more effectively suppressed.

[0013] The molding device may further include a retaining portion configured to seal the metal tube material while the fluid is being supplied via the fluid supply unit, thereby preventing buckling. When the fluid supply unit is attached to the metal tube material, the retaining portion prevents the metal tube material from shifting in the direction of the fluid supply unit's pressure, even when pressed with a certain degree of force. Alternatively, the retaining portion may retain the metal tube material being conveyed from a metal tube conveying device.

[0014] Effects of the Invention

[0015] According to the present disclosure, it is possible to provide a forming device for an expansion forming device that can perform sealing while suppressing the influence of a high-temperature metal tube material. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram showing a molding device according to an embodiment of the present disclosure.

[0017] Figure 2 It is a perspective view showing a part of the nozzle.

[0018] Figure 3 It is a cross-sectional view showing a sealing mechanism of the molding device according to this embodiment.

[0019] Figure 4 It is a cross-sectional view showing a sealing mechanism of the molding device according to this embodiment.

[0020] Figure 5 It is a three-dimensional diagram of the collet.

[0021] Figure 6 It is a cross-sectional view showing a sealing mechanism of a molding device according to a modified example. DETAILED DESCRIPTION

[0022] Hereinafter, preferred embodiments of the molding device disclosed herein will be described with reference to the accompanying drawings. In the drawings, the same or equivalent parts are denoted by the same reference numerals, and repeated descriptions are omitted.

[0023] Figure 1 1 is a schematic structural diagram of the molding device 1 according to this embodiment. Figure 1 As shown, the molding device 1 is a device for molding a metal tube having a hollow shape by blow molding. In this embodiment, the molding device 1 is arranged on a horizontal plane. The molding device 1 includes a molding die 2, a drive mechanism 3, a holding portion 4, a fluid supply portion 6, a cooling portion 7 and a control portion 8. In addition, in this specification, the metal tube material 40 (metal material) refers to the hollow object before the molding is completed in the molding device 1. The metal tube material 40 is a steel tube material that can be quenched. In addition, in the horizontal direction, the direction in which the metal tube material 40 extends during molding is sometimes referred to as the "length direction", and the direction orthogonal to the length direction is referred to as the "width direction".

[0024] The forming mold 2 is a mold for forming a metal tube material 40 into a metal tube, and has a lower main mold 11 (first main mold) and an upper main mold 12 (second main mold) facing each other in the up and down directions. The lower main mold 11 and the upper main mold 12 are composed of steel blocks. Recesses for accommodating the metal tube material 40 are respectively provided in the lower main mold 11 and the upper main mold 12. When the lower main mold 11 and the upper main mold 12 are in close contact with each other (closed mold state), a space of the target shape to be formed of the metal tube material is formed by each recess. Therefore, the surface of each recess becomes the forming surface of the forming mold 2. The lower main mold 11 is fixed to the base 13 via a mold seat, etc. The upper main mold 12 is fixed to the sliding part of the drive mechanism 3 via a mold seat, etc.

[0025] The driving mechanism 3 is a mechanism for moving at least one of the lower main mold 11 and the upper main mold 12. Figure 1 In the embodiment, the drive mechanism 3 is configured to move only the upper main mold 12. The drive mechanism 3 comprises a slider 21 that moves the upper main mold 12 to close the lower main mold 11 and the upper main mold 12; a pull-back cylinder 22 as an actuator that generates a force to pull the slider 21 upward; a main cylinder 23 that serves as a drive source for lowering and pressurizing the slider 21; and a drive source 24 that applies a driving force to the main cylinder 23.

[0026] The holding unit 4 is a mechanism for holding the metal tube 40 disposed between the lower main mold 11 and the upper main mold 12. The holding unit 4 includes a lower electrode 26 and an upper electrode 27 for holding the metal tube 40 at one longitudinal end of the forming mold 2, and a lower electrode 26 and an upper electrode 27 for holding the metal tube 40 at the other longitudinal end of the forming mold 2. The lower electrode 26 and the upper electrode 27 on both longitudinal sides hold the metal tube 40 by vertically clamping the metal tube 40 near its ends. Grooves corresponding to the outer circumference of the metal tube 40 are formed on the upper surface of the lower electrode 26 and the lower surface of the upper electrode 27. The lower electrode 26 and the upper electrode 27 are movable in the vertical direction in conjunction with the vertical movement of the fluid supply unit 6.

[0027] The fluid supply unit 6 is a mechanism for supplying high-pressure fluid into the interior of the metal tube 40 held between the lower main mold 11 and the upper main mold 12. The fluid supply unit 6 supplies high-pressure fluid to the metal tube 40, which has been heated to a high temperature by a heating furnace or the like in the preceding stage of the forming apparatus, thereby expanding the metal tube 40. The fluid supply unit 6 is located at both ends of the forming mold 2 in the longitudinal direction. The fluid supply unit 6 comprises a nozzle 31 for supplying fluid into the interior of the metal tube 40 from an opening at the end of the metal tube 40; a drive mechanism 32 for moving the nozzle 31 forward and backward relative to the opening of the metal tube 40; and a high-pressure fluid supply source 33 for supplying high-pressure fluid into the metal tube 40 via the nozzle 31. The drive mechanism 32 maintains a tight seal between the nozzle 31 and the end of the metal tube 40 during fluid supply and exhaust, and separates the nozzle 31 from the end of the metal tube 40 at other times. Alternatively, the fluid supply unit 6 can supply a gas such as high-pressure air or an inert gas as the fluid. Furthermore, the fluid supply unit 6 is configured as the same device together with the holding unit 4 having a mechanism for moving the metal tube material 40 in the vertical direction.

[0028] Return to Figure 1 The cooling unit 7 is a mechanism for cooling the forming die 2. By cooling the forming die 2, the cooling unit 7 can quickly cool the expanded metal tube material 40 when it contacts the forming surface of the forming die 2. The cooling unit 7 includes a flow path 36 formed inside the lower main die 11 and the upper main die 12, and a water circulation mechanism 37 that supplies cooling water to the flow path 36 and circulates it.

[0029] The control unit 8 is a device that controls a portion of the forming apparatus 1. The control unit 8 controls the drive mechanism 3, the holding unit 4, and the fluid supply unit 6. The control unit 8 repeatedly performs the operation of forming the metal tube material 40 using the forming die 2. Furthermore, the control unit 8 for the drive mechanism 3 can be independently provided from the control units 8 for the holding unit 4 and the fluid supply unit 6. For example, if the holding unit 4 and the fluid supply unit 6 are newly added to an existing press apparatus, the control unit 8 can be provided independently of the drive mechanism 3.

[0030] Specifically, the control unit 8 controls the timing of transport from a transport device such as a robotic arm to position the metal tube 40 between the lower and upper main molds 11, 12, which are in an open state. Alternatively, an operator can manually position the metal tube 40 between the lower and upper main molds 11, 12. Furthermore, the control unit 8 controls the actuators and other components of the holding unit 4 so that the lower electrodes 26 on both sides in the longitudinal direction support the metal tube 40, and then lowers the upper electrode 27 to clamp the metal tube 40.

[0031] The control unit 8 controls the driving mechanism 3 so that the upper main mold 12 descends and approaches the lower main mold 11, thereby closing the forming mold 2. On the other hand, the control unit 8 controls the fluid supply unit 6 to seal the openings at both ends of the metal tube material 40 with the nozzle 31 and supply fluid. As a result, the metal tube material 40 softened by heating expands and contacts the forming surface of the forming mold 2. Moreover, the metal tube material 40 is formed into a shape identical to the shape of the forming surface of the forming mold 2. In addition, in the case of forming a metal tube with a flange, after a portion of the metal tube material 40 is allowed to enter the gap between the lower main mold 11 and the upper main mold 12, the mold is further closed to flatten the entered portion to form a flange portion. When the metal tube material 40 contacts the forming surface, the metal tube material 40 is quenched by rapidly cooling the forming mold 2 cooled by the cooling unit 7.

[0032] Next, refer to Figures 2 to 5 The sealing mechanism 100 of the forming apparatus 1 according to this embodiment will be described in detail. The sealing mechanism 100 is a mechanism for sealing the metal tube material 40 in the forming apparatus 1 as an expansion forming apparatus for expansion-forming the metal tube material 40 . Figure 2 31 is a perspective view showing the nozzle 31. A sealing mechanism 100 is provided at the distal end of the nozzle 31. The sealing mechanism 100 prevents leakage of the high-pressure fluid supplied from the flow path 63 from the metal tube 40 when the distal end of the nozzle 31 is attached to the end of the metal tube 40.

[0033] like Figure 2 and Figure 3As shown, the sealing mechanism 100 includes a nozzle base member 70, a nozzle member 71, a clamping mechanism 72, and a hydraulic cylinder 73. In the following description, the direction in which the centerline CL of the nozzle 31 extends is sometimes referred to as the axial direction D1. In the axial direction D1, the metal tube material 40 side (i.e., the distal end side) is sometimes referred to as the "front," and the opposite side is sometimes referred to as the "rear." Furthermore, terms such as "radial direction" and "circumferential direction" are sometimes used with reference to the centerline CL.

[0034] The nozzle base member 70 is a base member that supports various components of the nozzle 31. The nozzle base member 70 has a flow path 63 extending along the center line CL. The nozzle base member 70 has a shaft portion 76 extending in the axial direction D1 along the center line CL, and an expansion portion 77 (also see FIG. 1 ) extending radially outward from the rear side of the shaft portion 76. Figure 2 ).

[0035] The nozzle component 71 is a component that is arranged inside the metal tube material 40 when supplying gas to the metal tube material 40. The nozzle component 71 is provided on the front side of the shaft portion 76 of the nozzle base component 70. A metal O-ring 79 is provided between the nozzle component 71 and the shaft portion 76. The metal O-ring 79 can prevent damage due to heat even when the heated metal tube material 40 comes into contact with the nozzle component 71. The nozzle component 71 has a cylindrical shape. A flow path 63 is formed on the center line CL of the nozzle component 71. The flow path 63 opens at the end face 71a on the front side of the nozzle component 71. Therefore, fluid is supplied to the inside of the metal tube material 40 from the end face 71a on the front side of the nozzle component 71. The outer peripheral surface 71b of the nozzle component 71 is designed to form a small gap with the inner peripheral surface of the metal tube material 40.

[0036] The clamping mechanism 72 is provided on the outer periphery of the nozzle member 71 and clamps the metal tube 40. The clamping mechanism 72 seals the metal tube 40 by deforming itself in the radial direction. In this embodiment, the clamping mechanism 72 contracts by applying an external force from the outer periphery to clamp the metal tube 40. The clamping mechanism 72 is located at a position corresponding to the nozzle member 71 and the shaft portion 76 of the nozzle base member 70 in the axial direction D1. The clamping mechanism 72 is a cylindrical body having a plurality of slits 84A and 84B and includes a collet 80 that can expand and contract in the radial direction. The detailed structure of the collet 80 will be described later.

[0037] The hydraulic cylinder 73 includes a cylinder body 90 and a cylinder rod 91. The cylinder body 90 is arranged on the outer peripheral side of the clamping mechanism 72. The cylinder body 90 is fixed to the extension portion 77 of the nozzle base component 70. The cylinder rod 91 is arranged between the clamping mechanism 72 and the cylinder body 90 in the radial direction. Furthermore, the front side area of ​​the cylinder rod 91 in the axial direction D1 is arranged so that the inner peripheral surface contacts the clamping mechanism 72. The cylinder rod 91 has a tapered surface 96 on the inner peripheral surface of the front end side. The tapered surface 96 is inclined in a manner gradually toward the outer peripheral side from the front side toward the rear side. Furthermore, the rear side area of ​​the cylinder rod 91 in the axial direction D1 can be inserted into the guide groove portion 78 of the extension portion 77 of the nozzle base component 70 so as to be reciprocatingly movable.

[0038] A hydraulic chamber 93 is formed between the cylinder body 90 and the cylinder rod 91 (see Figure 3 ) and hydraulic chamber 94 (reference Figure 4 ). The hydraulic chamber 93 is arranged at the rear side of the hydraulic chamber 94. The hydraulic fluid L1 of the cylinder main body 90 supplies the hydraulic fluid OL1 to the hydraulic chamber 93. As a result, the cylinder rod 91 moves forward by the hydraulic pressure based on the hydraulic fluid OL1. The hydraulic fluid OL2 is supplied to the hydraulic chamber 94 from the hydraulic fluid L2 of the cylinder main body 90 (refer to Figure 4 ). As a result, the cylinder rod 91 moves rearward due to the hydraulic pressure of the hydraulic oil OL2. In addition, multiple sealing components such as O-rings are provided between the cylinder rod 91 and the cylinder body 90. Furthermore, multiple sealing components are provided between the cylinder rod 91 and the guide groove portion 78.

[0039] refer to Figure 5 , the collet 80 will be described. Figure 5 As shown, the collet 80 has a cylindrical main body 81, a front end 82 located at the front side in the axial direction D1, and a rear end 83 located at the rear side in the axial direction D1. The main body 81 is formed with a plurality of slits 84A and 84B extending along the axial direction D1. The slits 84A and 84B radially penetrate the main body 81 and extend throughout the entire axial direction D1 of the main body 81. The slits 84A and 84B are alternately arranged circumferentially. Slits 84A are formed in the main body 81 and the rear end 83, but not in the front end 82. Therefore, at the locations of the slits 84A, the collet 80 is circumferentially divided at the rear end 83 and circumferentially connected at the front end 82. Slits 84B are formed in the main body 81 and the front end 82, but not in the rear end 83. Therefore, at the locations of the slits 84B, the collet 80 is circumferentially divided at the front end 82 and circumferentially connected at the rear end 83.

[0040] In this way, the collet 80 has a structure in which multiple tube walls are connected in a strip-like manner along the circumference. When the collet 80 is subjected to external force from the outer circumference, it deforms, compressing the gaps between the slits 84A and 84B. Consequently, the collet 80's circumferential length decreases, while simultaneously contracting in the radial direction. On the other hand, when the external force is released, the springs cause the slits 84A and 84B to return to their original gap sizes. Thus, the collet 80 automatically returns to its original shape.

[0041] The collet 80 has a tapered structure 86 disposed on the front side and a tapered structure 87 disposed on the rear side. The tapered structure 86 is disposed on the outer circumferential surface of the collet 80. The tapered structure 86 is inclined so as to gradually expand outward from the front end 82 toward the rear side. The tapered structure 87 is inclined so as to gradually expand outward from the rear end 83 toward the front side. As a result, the collet 80 is subjected to external forces via the tapered structures 86 and 87 as the cylinder rod 91 moves rearward in the axial direction D1, causing it to deform radially. This deformation will be described later. The outer circumferential surface 80b between the tapered structures 86 and 87 of the collet 80 extends parallel to the axial direction D1. The collet 80 is a metal component. Heat-resistant spring steel is preferably used as the metal material. Therefore, by forming the clamping mechanism 72 from metal, it can seal the metal tube 40 through metal contact during clamping.

[0042] refer to Figure 3 and Figure 4 Next, the arrangement of the collet 80 within the sealing mechanism 100 will be described. The inner circumferential surface 80a of the collet 80 is arranged to radially oppose the outer circumferential surface 71b of the nozzle member 71 and the outer circumferential surface 76a of the shaft portion 76 of the nozzle base member 70. The front tapered structure 86 is arranged to surface-contact the tapered surface 96 of the cylinder rod 91. The rear tapered structure 87 is arranged to surface-contact the tapered surface 75a formed on the nozzle base member 70. Furthermore, a restricting surface 75b is formed on the inner side of the tapered surface 75a of the nozzle base member 70 to restrict the movement of the collet 80.

[0043] The clamping and sealing method performed by the clamping mechanism 72 using the collet 80 will be described. Figure 3 The state shown is the state before clamping. In this state, the collet 80 is in an uncontracted state. If starting from this state, as Figure 4As shown, when hydraulic oil OL2 is supplied to the hydraulic chamber 94, the cylinder rod 91 moves rearward. The cylinder rod 91 contacts the tapered structure 86, causing the entire collet 80 to move rearward. Guided by the tapered surface 75a, the collet 80 moves rearward to the position of the restricting surface 75b. During this rearward movement, the collet 80 contacts the tapered surface 75a at the tapered structure 87. Consequently, the collet 80 receives an external force from the tapered surface 75a, acting from the outer periphery toward the inner periphery, via the tapered structure 87. As a result, the collet 80 contracts and deforms inwardly due to the narrowing of the slits 84A and 84B. Furthermore, the collet 80 contacts the tapered surface 96 at the tapered structure 86, moving rearward. Consequently, the collet 80 receives an external force from the tapered surface 96, acting from the outer periphery toward the inner periphery, via the tapered structure 86. As a result, the collet 80 contracts and deforms toward the inner peripheral side due to the narrowing of the slits 84A and 84B.

[0044] As a result, the collet 80 contracts inward, clamping the metal tube 40 between the nozzle member 71 and the collet 80. At this point, the gaps between the slits 84A and 84B of the collet 80 decrease. The clamping deforms the metal tube 40, causing the inner circumference of the metal tube 40 to adhere tightly to the outer circumference 71b of the nozzle member 71, creating a sealed state that prevents high-pressure air from leaking from the inside of the metal tube 40.

[0045] If the metal tube material 40 is formed, Figure 3 As shown, hydraulic oil OL1 is supplied to the hydraulic chamber 93, causing the cylinder rod 91 to move forward. At this point, the external force acting on the collet 80 is released. The collet 80 returns to its original position due to the spring action. As the collet 80 expands, the entire collet 80 moves forward, guided by the tapered structure 87.

[0046] The nozzle base member 70 can also supply cooling air to the collet 80 via a path through the flow path L3 that leads to the restriction surface 75b or a path that utilizes the guide groove 78. Furthermore, the collet 80 includes a plurality of slits 84A and 84B that extend substantially throughout the axial direction D1. Therefore, the collet 80 is cooled by the cooling air while the heat transfer area is increased by the slits 84A and 84B.

[0047] Next, the effects of the molding device 1 according to this embodiment will be described.

[0048] In this sealing mechanism 100, the nozzle member 71 is disposed inside the metal tube 40, and the clamping mechanism 72 is provided on the outer periphery of the nozzle member 71. Therefore, the clamping mechanism 72 provides a seal, thereby suppressing leakage of the fluid supplied from the nozzle member 71 into the metal tube 40. The clamping mechanism 72 seals the metal tube 40 by deforming in the radial direction. Because the mechanism that clamps the metal tube 40 deforms to seal, the clamping mechanism 72 can be made of a material with higher heat resistance than sealing components such as resin O-rings. This allows sealing while suppressing the effects of the high-temperature metal tube 40.

[0049] For example, when heating the metal tube material 40 solely through electrical heating, the end portion does not reach a high temperature compared to the electrode, so conventional O-ring sealing can be used. However, in a heating method that heats the entire tube, including the end portion, through furnace heating, it is difficult to use O-rings. In contrast, the present invention achieves good sealing even with furnace heating.

[0050] The clamping mechanism 72 can be contracted by applying an external force from the outer peripheral side to clamp the metal tube material 40. Thus, the clamping mechanism can be configured with a simple design.

[0051] The clamping mechanism 72 can be made of metal to seal the metal tube 40 by metal contact during clamping. This allows sealing to be performed while suppressing the influence of the high-temperature metal tube 40.

[0052] The clamping mechanism 72 is a cylindrical body having a plurality of slits 84A, 84B, and may include a collet 80 that can be contracted and restored in the radial direction. In this case, clamping and sealing can be performed with a simple structure.

[0053] The clamp mechanism 72 has tapered structures 86 and 87 and can deform radially as it moves in the axial direction D1 by applying external force via the tapered structures 86 and 87. In this case, the movement of the clamp mechanism 72 in the axial direction D1 can be easily converted into external force for radial deformation.

[0054] Furthermore, the molding device 1 is provided with a sealing mechanism 100, which seals against leakage of the fluid from the metal tube material 40 when the fluid is supplied from the fluid supply portion 6 to the metal tube material 40 heated by the heating portion (here, an external heating furnace). Therefore, the sealing of the sealing mechanism 100 suppresses leakage of the fluid supplied from the fluid supply portion 6 to the inside of the metal tube material 40 to the outside of the metal tube material 40. Here, the sealing mechanism 100 contacts the metal tube material 40 through a non-resin material and seals without applying an axial force to the metal tube material. Thus, a non-resin material having a higher heat resistance than a sealing component such as a resin O-ring can be selected as the material of the sealing mechanism 100. Thus, sealing can be performed while suppressing the influence of the high-temperature metal tube material 40.

[0055] The nozzle assembly 71 of the fluid supply unit 6 is positioned inside the metal tube 40, while the collet 80 of the sealing mechanism 100 is positioned outside the metal tube 40. When the fluid is supplied by the fluid supply unit 6, the sealing mechanism 100 can seal the metal tube 40 by moving its inner peripheral surface 80a, which serves as the sealing surface, radially toward the metal tube 40. In this manner, the sealing mechanism 100 can radially press the sealing surface against the metal tube 40, thereby further suppressing fluid leakage from the metal tube 40.

[0056] The molding device 1 may further include a retaining portion 4 for sealing the metal tube 40 to prevent it from buckling when fluid is supplied by the fluid supply portion 6. When the nozzle member 71 of the fluid supply portion 6 is attached to the metal tube 40, the retaining portion 4 prevents the metal tube 40 from shifting in the direction of the pressure from the nozzle member 71 of the fluid supply portion 6, even when the nozzle member 71 is pressed with a certain degree of force. Alternatively, the retaining portion 4 can retain the metal tube 40 after it has been conveyed from a conveying device for the metal tube 40.

[0057] The present invention is not limited to the above-described embodiment.

[0058] For example, the clamping mechanism 72 may be expanded by applying an external force from the inner peripheral side to clamp the metal pipe material 40. This allows for a compact structure with a small diameter.

[0059] Furthermore, the clamping mechanism 72 is not limited to the one having the collet 80 , and any other mechanism that can perform clamping and sealing can be modified as appropriate.

[0060] Furthermore, the structure of the sealing mechanism 100 is not limited to Figure 3 and Figure 4 , and can also be appropriately changed into various structures.

[0061] Furthermore, in the above-described embodiment, furnace heating is employed as a method for heating the metal pipe material, but electric heating using electrodes may also be employed.

[0062] In addition, as a sealing mechanism, it is possible to use Figure 6 The sealing mechanism 100 is shown. Figure 6 The sealing mechanism 100 shown differs from the above-described embodiment in that it does not include the clamping mechanism 72 described above, but instead performs sealing from the inside of the metal tube material 40. The nozzle 31 includes a nozzle base component 170 and a nozzle component 171. The nozzle component 171 is inserted into the opening of the metal tube material 40, which is held by the electrodes 26 and 27. Here, a tapered surface 40a is formed on the inner circumferential surface of the end of the metal tube material 40. The tapered surface 40a is inclined so that the inner diameter increases toward the end. This tapered surface 40a can be formed by pre-processing. In contrast, the outer circumferential surface of the nozzle component 171 includes a tapered surface 171b. The tapered surface 171b is inclined so that the outer diameter decreases from the rear side to the front side. The inclination angle of the tapered surface 171b is the same as the inclination angle of the tapered surface 40a. When the nozzle component 171 is inserted into the metal tube material 40, the tapered surface 171b comes into surface contact with the tapered surface 40a, thereby performing sealing. As nozzle member 171 moves forward, inclined tapered surface 171b, serving as a sealing surface, moves radially outward relative to metal tube material 40, thereby achieving sealing. Nozzle member 171 is made of a non-resin material such as metal. Therefore, tapered surface 171b, serving as a sealing surface, is also made of a non-resin material.

[0063] When high-pressure fluid is supplied to the metal tube 40, the metal tube 40 is heated to a high temperature and softened. Typically, when long tubes are heated to a high temperature, the length of the tube 1 meter changes by 0.1% for every 100°C increase in temperature. As the high-pressure fluid is supplied to the metal tube 40, the tube 40 shrinks as its temperature decreases. Therefore, the control unit 8 controls the nozzle 31 to prevent the tapered surfaces 40a and 171b from separating.

[0064] To prevent the tapered surface 40a of the metal tube 40 from separating from the tapered surface 171b of the nozzle member 171, the pushing force of the nozzle member 171 must be adjusted and controlled based on the pressure of the high-pressure fluid within the metal tube 40, ensuring an appropriate pushing force. As mentioned above, the metal tube 40 softens when heated. Therefore, if excessive pushing force is applied, the metal tube 40 may buckle, or the nozzle member 171 may be inserted too far into the metal tube 40. On the other hand, if the pushing force is too low, the nozzle member 171 may retreat due to the pressure applied during the supply of high-pressure fluid, causing the tapered surfaces 40a and 171b to separate. Therefore, the control unit 8 controls the pushing force of the nozzle member 171 to be adjusted in real time based on the internal pressure.

[0065] On the other hand, in order to be able to press the nozzle member 171 against the end of the metal tube 40 with an excessively large pressing force, it is also possible to firmly clamp and secure the metal tube 40 itself. However, even if an attempt is made to firmly clamp and hold the metal tube 40, which has softened due to heating, the metal tube 40 itself will deform, making it impossible to clamp the metal tube 40 to a level that exceeds the pressing force of the nozzle member 171. Therefore, the control unit 8 controls the pressing force of the nozzle member 171 based on the internal pressure of the high-pressure fluid.

[0066] After the expansion molding is completed, to eliminate the pressure of the high-pressure fluid, the pushing force of the nozzle member 171 must be reduced in response to the internal pressure. If the control unit 8 does not control the reduction of the pushing force, the pushing force on the tapered surface 40a at the end of the metal tube material 40 increases, causing the nozzle member 171 to embed in the metal tube material 40. Therefore, the control unit 8 needs to control the reduction of the pushing force of the nozzle member 171. Alternatively, the control unit 8 can use position control to fix the nozzle member 171 at a constant position.

[0067] Thus, the molding device 1 is provided with a sealing mechanism 100, which seals against leakage of the fluid from the metal tube material 40 when the fluid is supplied from the fluid supply portion 6 to the metal tube material 40 heated by the heating portion (here, an external heating furnace). Therefore, the sealing of the sealing mechanism 100 suppresses leakage of the fluid supplied from the fluid supply portion 6 to the inside of the metal tube material 40 to the outside of the metal tube material 40. Here, the sealing mechanism 100 contacts the metal tube material 40 with the tapered surface 171b of the nozzle component 171 made of a non-resin material, and seals without applying an axial force to the metal tube material 40. Thus, a non-resin material having a higher heat resistance than a resinous sealing component such as an O-ring can be selected as the material of the sealing mechanism 100. Thus, sealing can be performed while suppressing the influence of the high-temperature metal tube material 40.

[0068] The nozzle member 171 of the fluid supply unit 6 is disposed inside the metal tube 40, and the tapered surface 171b of the nozzle member 171 of the sealing mechanism 100 is also disposed inside the metal tube 40. When the fluid is supplied from the fluid supply unit 6, the sealing mechanism 100 can move the tapered surface 171b, serving as the sealing surface, radially toward the metal tube 40 to achieve sealing. In this case, since the sealing mechanism 100 can radially press the sealing surface against the metal tube 40, leakage of the fluid from the metal tube 40 can be further suppressed.

[0069] The molding apparatus 1 may further include a retaining portion 4 for sealing the metal tube 40 while the fluid is supplied by the fluid supply unit 6, thereby preventing the metal tube 40 from buckling. When the nozzle member 171 of the fluid supply unit 6 is attached to the metal tube 40, the retaining portion 4 prevents the metal tube 40 from shifting in the direction of the pressure from the nozzle member 171 of the fluid supply unit 6, even when the nozzle member 171 is pressed with a certain degree of force. Alternatively, the retaining portion 4 can retain the metal tube 40 after it has been conveyed from a conveying device for the metal tube 40.

[0070] [Implementation Method 1]

[0071] A sealing mechanism for sealing a metal tube material in an expansion forming device for expansion forming the metal tube material, the sealing mechanism comprising:

[0072] a nozzle component, disposed inside the metal tube material; and

[0073] A clamping mechanism is provided on the outer periphery of the nozzle member and clamps the metal pipe material.

[0074] The clamping mechanism seals the metal tube material by deforming the clamping mechanism itself in the radial direction.

[0075] [Implementation Method 2]

[0076] The sealing mechanism according to embodiment 1, wherein:

[0077] The clamping mechanism contracts by applying an external force from the outer peripheral side to clamp the metal pipe material.

[0078] [Implementation Method 3]

[0079] The sealing mechanism according to embodiment 1, wherein:

[0080] The clamping mechanism expands by applying an external force from the inner peripheral side to clamp the metal pipe material.

[0081] [Implementation Method 4]

[0082] The sealing mechanism according to embodiment 1, wherein:

[0083] The clamping mechanism is formed of metal, and thus seals the metal pipe material through metal contact during clamping.

[0084] [Implementation 5]

[0085] The sealing mechanism according to embodiment 1, wherein:

[0086] The clamping mechanism is a cylindrical body having a plurality of slits and includes a collet capable of contracting and restoring in the radial direction.

[0087] [Implementation Method 6]

[0088] The sealing mechanism according to embodiment 1, wherein:

[0089] The clamping mechanism has a tapered structure, and is deformed in the radial direction by an external force applied via the tapered structure as the clamping mechanism moves in the axial direction.

[0090] Explanation of symbols

[0091] 40 - metal tube material, 71 - nozzle component, 72 - clamping mechanism, 80 - collet, 84A, 84B - slit, 86, 87 - tapered structure, 100 - sealing mechanism.

Claims

1. A molding device comprising: a fluid supply portion, disposed at an end portion of the metal tube material, and supplying the fluid into the interior of the metal tube material through an opening at the end portion; and a sealing mechanism for sealing against leakage of the fluid from the metal tube material when the fluid is supplied from the fluid supply portion to the metal tube material heated by the heating portion; The sealing mechanism seals the metal tube material without applying an axial force to the metal tube material by contacting the metal tube material with a non-resin material.

2. The molding device according to claim 1, wherein: The fluid supply portion is arranged inside the metal tube material, The sealing mechanism is disposed at at least one of the inside and the outside of the metal tube material, and when the fluid is supplied from the fluid supply unit, the sealing mechanism moves a sealing surface in a radial direction toward the metal tube material to perform sealing. 3 . The molding device according to claim 1 , further comprising a holding portion configured to seal the metal pipe to prevent buckling when the fluid is supplied through the fluid supply portion.

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