JP5662648B2 - Hydroform molding method and hydroform molding apparatus - Google Patents

Description

  The present invention relates to a hydroform molding method and a hydroform molding apparatus.

  Conventionally, in a hydroform molding method, a hollow molded product having a predetermined shape is integrally molded by applying an axial force to a pipe member and supplying a high-pressure liquid into the pipe member. It has become.

  FIG. 2 is a first diagram illustrating a conventional hydroform molding method, and FIG. 3 is a second diagram illustrating a conventional hydroform molding method.

  In the figure, 110 is a hydroform molding device, 111 is a lower mold attached to the frame Fr, 112 is an upper mold disposed so as to be able to contact with and separate from the lower mold 111, and the lower mold When the die 111 and the upper die 112 are brought into contact with each other and the die is closed, a cavity C having the same inner shape as the outer shape of the molded product is formed in the lower die 111 and the upper die 112. The cavity C includes a tube member accommodating portion 114 for accommodating the tube member 113 and a tube expanding portion 15 that is communicated with the tube member 113 and projects a predetermined portion of the tube member 113.

  In addition, 118 and 119 seal the cavity C, and pushers that press the tube member 113 from both ends, and 120 and 121 are disposed adjacent to the pushers 118 and 119, and are supplied from a supply source (not shown). This is a liquid introduction part for supplying high-pressure liquid into the tube member 113, and the liquid supply path 123 penetrates the pusher 118 and the liquid introduction part 120, and penetrates the pusher 119 and the liquid introduction part 121. A liquid supply path 124 is formed.

  Reference numerals 126 and 127 denote drive cylinders for pressing the tube member 113 from both ends and applying a force in the axial direction.

  In the hydroform molding apparatus 110 having the above-described configuration, the pipe member 113 is set in the mold apparatus including the lower mold 111 and the upper mold 112, the drive cylinders 126 and 127 are driven, and the pipe members 113 are driven by the pushers 118 and 119. Is pressed from both ends to apply force in the axial direction, and when high-pressure liquid is supplied into the pipe member 113 via the liquid supply paths 123 and 124, the pipe member 113 is pushed toward the center of the cavity C. Bulges outward in the radial direction. Then, the pushed-in tube member 113 is pressed against the inner peripheral surface of the tube member accommodating portion 114, and as shown in FIG. 3, the tube member 113 is caused to enter the expanded portion 115 and pressed against the inner peripheral surface of the expanded portion 115. It is done.

  In this way, the tube member 113 is deformed in accordance with the inner shape of the cavity C, and a hollow molded product is integrally molded (for example, see Patent Document 1).

JP 2002-35853 A

  However, in the conventional hydroform molding method, when only a part of the center of the long pipe member 113 is to be expanded, the inner peripheral surface of the pipe member accommodating portion 114 and the outer peripheral surface of the pipe member 113 are slid. Since the moving part is large and the frictional resistance is increased accordingly, it is difficult to push the tube member 113 toward the center of the cavity C only by pressing from both ends.

  In addition, when the volume of the pipe expanding portion 115 is large, the amount of the pipe member 113 that enters the pipe expanding portion 115 increases. Therefore, it is necessary to increase the pushing amount of the pipe member 113 by the pushers 118 and 119. As it progresses, the frictional resistance generated between the inner peripheral surface of the tube member accommodating portion 114 and the outer peripheral surface of the tube member 113 increases, and it becomes difficult to push the tube member 113 toward the center of the cavity C. .

  Therefore, the pipe member 113 cannot sufficiently enter the expanded portion 115, and the quality of the molded product is deteriorated.

  An object of the present invention is to provide a hydroform molding method and a hydroform molding apparatus that can solve the problems of the conventional hydroform molding method and improve the quality of a molded product.

  Therefore, in the hydroform molding method of the present invention, in the first step, the heated portion set at a predetermined location of the pipe material is locally heated, the pipe material is pressed from both ends, and the A hollow preform is formed by generating buckling deformation by generating buckling deformation in the heated portion.

  In the second step, a high-pressure molding medium is supplied into the preform, and the preform is deformed in accordance with the inner shape of the cavity.

  According to the present invention, in the hydroform molding method, in the first step, a heated portion set at a predetermined location of the pipe material is locally heated, the pipe material is pressed from both ends, and the covered material is obtained. A hollow preform is formed by generating buckling deformation by generating buckling deformation in the heated portion.

  In the second step, a high-pressure molding medium is supplied into the preform, and the preform is deformed in accordance with the inner shape of the cavity.

  In this case, since the buckled deformation portion is formed in the preform, the contact area between the inner peripheral surface of the cavity and the outer peripheral surface of the preform can be reduced. Therefore, since the frictional resistance generated between the inner peripheral surface of the cavity and the outer peripheral surface of the preform can be reduced, the preform can be sufficiently pushed toward the center of the cavity. As a result, the quality of the molded product can be improved.

It is a conceptual diagram which shows the primary shaping | molding apparatus in the 1st Embodiment of this invention. It is a 1st figure explaining the conventional hydroform molding method. It is a 2nd figure explaining the conventional hydroform molding method. It is a conceptual diagram which shows the secondary shaping | molding apparatus in the 1st Embodiment of this invention. It is a control block diagram of the hydroform molding apparatus in the 1st Embodiment of this invention. It is a 1st figure explaining the hydroform shaping | molding method in the 2nd Embodiment of this invention. It is a 2nd figure explaining the hydroform shaping | molding method in the 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a conceptual diagram showing a primary molding apparatus according to the first embodiment of the present invention, FIG. 4 is a conceptual diagram showing a secondary molding apparatus according to the first embodiment of the present invention, and FIG. It is a control block diagram of the hydroforming apparatus in 1 embodiment.

  First, in the hydroforming method, a primary forming apparatus for forming a hollow preform pipe as a preform with a pipe as a pipe material in the first step will be described.

  In FIG. 1, 10 is a primary molding apparatus, 11 is a pipe conveyed in the direction of arrow A, and 12 is movably disposed on the upstream side in the conveyance direction of the pipe 11, and a first grip for gripping the pipe 11. A chuck 13 serving as a member is disposed on the downstream side of the chuck 12 in the conveying direction of the pipe 11 so as to be movable independently of the chuck 12, and serves as a second gripping member that grips the pipe 11. 15 is a bar as a guide member for guiding the chucks 12 and 13, 18 is a first moving mechanism for moving the chuck 12 in the arrow A direction, and 19 is a second moving mechanism for moving the chuck 13 in the arrow A direction. It is a moving mechanism. The chucks 12 and 13 constitute first and second pressing portions that press the pipe 11 from both ends and compress the pipe 11.

  In the present embodiment, the pipe 11 is formed of a metal material such as aluminum, stainless steel, or iron, but can be formed of a resin. Further, in the present embodiment, a pipe 11 having a predetermined length is used, but a long pipe wound around a winder (not shown) is used for a feeding machine (not shown) at one end. can do.

  Each of the chucks 12 and 13 has a structure surrounding the pipe 11, holds the pipe 11 with a predetermined gripping force, and the first gripping position gripped by the chuck 12 in the pipe 11 is gripped by the chuck 13. The second grip position is set, and the processing region of the pipe 11 is set between the first and second grip positions. Then, the pipe 11 is processed in the processing region, buckling deformation (wrinkle) is generated at a predetermined portion of the pipe 11, and a plurality of buckling deformation portions 20 as deformation portions having a predetermined height are formed. The

  For this purpose, an annular coil 14 as a heating body is disposed at a predetermined location in the processing region so as to surround the pipe 11, and an annular heated portion is set at a portion facing the coil 14 in the pipe 11. The The coil 14 heats the heated portion locally in the axial direction and entirely in the circumferential direction. A non-contact temperature sensor 40 as a temperature detector for detecting the temperature of the pipe 11 is disposed adjacent to the coil 14.

  In the present embodiment, an annular coil 14 is used as a heating body, and an annular heated portion is set. However, any other shape coil is used, and any other shape is used. The heated part can be set. In the present embodiment, a current is supplied to the coil 14 and the pipe 11 is heated by high-frequency heating. However, a heater is used in place of the coil 14 to supply a current to the heater, and the pipe 11 is heated. 11 can also be heated by Joule heat. Further, the laser beam can be irradiated to the pipe 11 by a laser device or the like to heat a predetermined portion of the pipe 11.

  The first moving mechanism 18 includes a support portion 21 that supports the chuck 12, a ball nut (not shown) attached to the support portion 21, a ball screw shaft 22 that meshes with the ball nut, A motor 23 as a first drive unit connected to the ball screw shaft 22 is provided. When the ball screw shaft 22 is rotated by driving the motor 23, the support portion 21 is moved in the arrow A direction along the bar 15. For this purpose, a guide hole (not shown) for penetrating the bar 15 is formed in the support portion 21. The ball nut and the ball screw shaft 22 constitute a ball screw as a motion direction converting portion, and the rotational motion of the ball screw shaft 22 is converted into the straight motion of the ball nut. The first conversion element is constituted by the ball nut, and the second conversion element is constituted by the ball screw shaft 22.

  The second moving mechanism 19 includes a support portion 25 that supports the chuck 13, a ball nut (not shown) attached to the support portion 25, a ball screw shaft 26 that meshes with the ball nut, and the ball screw shaft 26. And a motor 27 or the like as a second drive unit connected to the motor. When the ball screw shaft 26 is rotated by driving the motor 27, the support portion 25 is moved along the bar 15 in the direction of arrow A. Therefore, a guide hole (not shown) for penetrating the bar 15 is formed in the support portion 25. The ball nut and the ball screw shaft 26 constitute a ball screw as a motion direction converting portion, and the rotational motion of the ball screw shaft 26 is converted into the straight motion of the ball nut. The first conversion element is constituted by the ball nut, and the second conversion element is constituted by the ball screw shaft 26.

  In the present embodiment, the motors 23 and 27 are arranged as the first and second drive units in the first and second moving mechanisms 18 and 19, but they are replaced with the motors 23 and 27. A hydraulic cylinder can be used. In that case, the said support parts 21 and 25 are attached to the piston of a hydraulic cylinder.

  In the primary molding apparatus 10 having the above-described configuration, when a plurality of buckling deformation portions 20 are formed on the pipe 11, the pipe 11 is cut into a predetermined length according to the dimensions of the molded product. A pipe is formed.

  Next, a secondary molding apparatus for molding a molded product with a preform pipe will be described.

  In FIG. 4, 50 is a secondary molding apparatus, 51 is a lower mold as a first mold attached to the frame Fr via the attachment plate 52, and 54 is a support member (not shown) via the attachment plate 55. The upper mold is a second mold that is attached and is disposed so as to be able to contact with and separate from the lower mold 51. The lower mold 51 and the upper mold 54 constitute a mold device 57. The

  A mold opening / closing device (not shown) for moving the upper die 54 in the vertical direction by moving the support member in the vertical direction is disposed above the support member. When the mold opening / closing device is driven and the lower mold 51 and the upper mold 54 are brought into contact with each other and the mold is clamped, the outer shape of the molded product is placed between the lower mold 51 and the upper mold 54. A cavity C having the same inner shape is formed. The cavity C is communicated with a preformed product housing portion 63 for housing the preform pipe 61 molded in the primary molding apparatus 10 and the preformed product housing portion 63, and a predetermined portion of the preform pipe 61 is connected to the cavity C. An expanded pipe portion 64 for projecting is provided. The preform pipe 61 includes a pipe body 62 and a plurality of buckling deformation portions 20.

  In addition, 65 and 66 are disposed at both ends of the mold device 57 to seal the cavity C and pushers 67 and 68 as first and second pressing portions for pressing the preform pipe 61 from both ends. Is disposed adjacent to the pushers 65, 66, and serves as a molding medium introducing portion for supplying a liquid as a high-pressure molding medium supplied from a supply source (not shown) into the preform pipe 61. A liquid supply section 71 is formed through the pusher 65 and the liquid introduction section 67, and a liquid supply path 72 is formed through the pusher 66 and the liquid introduction section 68. The liquid supply paths 71 and 72 constitute a medium supply path. As the liquid, water, oil or the like is used.

  Drive cylinders 73 and 74 are arranged as press drive parts for pressing the both ends of the preform pipe 61 via the pushers 65 and 66 and applying force in the axial direction, adjacent to the liquid introduction parts 67 and 68. Established. The drive cylinders 73 and 74 include a cylinder (not shown) and a piston slidably disposed in the cylinder, and the piston is attached to the liquid introduction portions 67 and 68. The drive cylinders 73 and 74 are disposed in a hydraulic circuit and receive oil of a predetermined pressure generated by adjusting the opening of a pressure adjustment valve (not shown) as a pressure adjustment member. The both ends of the pipe 61 are pressed.

  If necessary, an annular seal member 78 as a sealing member can be disposed between the outer peripheral surface of both ends of the preform pipe 61 and the inner peripheral surface of the cavity C.

  Next, a control device of the hydroform molding device will be described.

  In FIG. 5, 30 is a control unit, 31 is a motor driver, 34 and 35 are encoders as rotation speed detection units, 39 is an oscillation circuit, 40 is a temperature sensor, 75 is a hydraulic circuit control unit, and 76 is a forming medium supply member. An on-off valve, 81 is a storage device, and 82 is an operation unit. The control unit 30 includes the motor driver 31, encoders 34 and 35, an oscillation circuit 39, a temperature sensor 40, a hydraulic circuit control unit 75, and an on-off valve 76. The storage device 81 and the operation unit 82 are connected.

  The motors 23 and 27 are connected to the motor driver 31, and the encoders 34 and 35 detect the magnetic pole positions and rotational speeds of the motors 23 and 27. The coil 14 is connected to the oscillation circuit 39 via a transformer 41. Then, solenoids s 1 and s 2 as valve drive elements of the pressure regulating valve 77 are connected to the hydraulic circuit control unit 75. The primary forming apparatus 10, the secondary forming apparatus 50, the control device, etc. constitute a hydroform forming apparatus.

  Next, the operation of the hydroform molding apparatus having the above-described configuration will be described.

  In this embodiment, as shown in FIG. 1, in the first step, the heated portion of the pipe 11 is moved in the direction of arrow A while being heated by the coil 14, and the pipes 12 and 13 are used to move the pipe. In this embodiment, a plurality of annular buckling deformed portions 20 having a shape corresponding to the shape of the coil 14 are formed on the pipe 11 by pressing 11 with a predetermined force from both ends.

  For this purpose, a conveyance processing unit (not shown) of the control unit 30 performs a conveyance process, sends an instruction to the motor driver 31, drives the motors 23 and 27, and moves the chucks 12 and 13 at a predetermined movement speed in the direction of arrow A. Move to.

That is, when the target moving speed representing the target value of the moving speed of the chucks 12 and 13 is va, the target rotating speed representing the target value of the rotating speed of the motors 23 and 27 is Na, and the constant is k, the target rotating speed is obtained. Na is
Na = k · va
To be.

  The encoders 34 and 35 detect the magnetic pole positions and rotation speeds of the motors 23 and 27, and send the detected rotation speeds, that is, the detected rotation speeds to the control unit 30.

  The conveyance processing means reads each detected rotation speed, calculates each deviation between each detected rotation speed and the target rotation speed Na, and supplies the deviations to the motors 23 and 27 so that each deviation becomes zero (0). Control the current.

  Subsequently, when the heated portions set in advance in a plurality of locations in the axial direction of the pipe 11 reach a position facing the coil 14, the processing means (not shown) of the control unit 30 performs processing, While heating a to-be-heated part, the pipe 11 is pressed from both ends (it compresses in an axial direction). That is, the heat treatment means of the processing means performs a heat treatment and supplies current to the coil 14 to heat and soften the heated portion. The compression processing means of the processing means performs compression processing, drives the motors 23 and 27 independently, moves the chuck 13 at the predetermined moving speed, and sets the moving speed of the chuck 12 to that of the chuck 13. The pipe 11 is moved in the direction of arrow A with a predetermined value higher than the moving speed, and the pipe 11 is pressed from both ends and processed. Whether or not the heated portion has reached the position facing the coil 14 can be determined based on the magnetic pole position detected by the encoder 34.

When the target moving speed representing the target value of the moving speed of the chuck 12 is v1, and the target moving speed representing the target value of the moving speed of the chuck 13 is v2, the target moving speeds v1 and v2 are:
v1> v2
To be. The target moving speeds va and v2 are made equal.

Therefore, when the target rotational speed that represents the target value of the rotational speed of the motor 23 is N1, the target rotational speed that represents the target value of the rotational speed of the motor 27 is N2, and the constant is k, the target rotational speeds N1 and N2 Is
N1 = k · v1
N2 = k · v2
And
N1> N2
To be. Since the target moving speeds va and v2 are made equal, the target rotational speeds Na and N2 are also made equal.

  The compression processing means reads each detected rotational speed, calculates each deviation between each detected rotational speed and each target rotational speed N1, N2, and supplies the deviations to the motors 23, 27 so that each deviation becomes zero. Control the current.

In the present embodiment, when the motors 23 and 27 are driven at the target rotational speeds N1 and N2, the speed difference Δv between the chuck 12 and the chuck 13 is
Δv = v1−v2
To be.

In this way, when the heated portion of the pipe 11 is heated and the vip 11 is pressed from both ends, the heated and softened heated portion is pressed in the axial direction, and the processing between the chuck 12 and the chuck 13 is performed. The area is the length d per unit time.
d = Δv
Only shortened. As a result, the portion to be heated causes a buckling deformation corresponding to the length d. In this case, since the cross section of the pipe 11 has a circular shape, the pipe 11 is easily deformed radially outward and is hardly deformed radially inward. Therefore, the buckling deformation occurs outward in the radial direction, and the buckling deformation portion 20 that protrudes outward in the radial direction is formed.

  Thus, when the buckling deformation part 20 is formed in the pipe 11, the pipe 11 is cut | disconnected by predetermined length, and the preform pipe 61 is shape | molded.

  Since the speed difference Δv is equal to the length d that the machining area is shortened per unit time, the speed difference change processing means of the compression processing means performs speed difference change processing to change the speed difference Δv. Thus, the height of each buckling deformed portion 20 can be changed.

  That is, when the speed difference Δv is increased, the length d at which the machining area is shortened per unit time is increased, so that the height of each buckling deformed portion 20 can be increased. On the other hand, when the speed difference Δv is reduced, the length d at which the machining region is shortened per unit time is reduced, so that the height of each buckling deformed portion 20 can be reduced.

  Next, in the second step, as shown in FIG. 4, when the preform pipe 61 is set in the mold device 57 and a high-pressure liquid is supplied into the preform pipe 61, the preform pipe 61 is in the radial direction. The product is swelled outward to form a molded product.

  For this purpose, a mold opening / closing processing means (not shown) of the control unit 30 performs a mold opening / closing process, drives the mold opening / closing device, moves the upper mold 54 upward, and moves the preform pipe 61 to the lower mold. The upper mold 54 is moved downward and brought into contact with the lower mold 51 to close the mold. Thus, when the preform pipe 61 is set in the mold apparatus 57, the mold opening / closing processing means drives the mold opening / closing apparatus to press the upper mold 54 against the lower mold 51, thereby clamping the mold. I do. Then, a pressing processing means (not shown) of the control unit 30 performs a pressing process, sends an instruction to the hydraulic circuit control unit 75, operates the pressure adjusting valve 77 by driving the solenoids s1, s2, and a driving cylinder 73, 74 is driven, the preform pipe 61 is pressed from both ends with a predetermined pressure by the pushers 65 and 66, and a force is applied in the axial direction.

  At this time, a molding processing means (not shown) of the control unit 30 performs a molding process, opens the on-off valve 76, and supplies a high-pressure liquid into the preform pipe 61 via the liquid supply passages 71 and 72. The pipe 61 is pushed toward the center of the cavity C and bulges outward in the radial direction. The pushed preform pipe 61 is pressed against the inner peripheral surface of the preformed product accommodation portion 63, is caused to enter the pipe expanding portion 64, and is pressed against the inner peripheral surface of the pipe expanding portion 64.

  In this way, the preform pipe 61 is deformed corresponding to the inner shape of the cavity C, and a hollow molded product is integrally molded.

  In this embodiment, the push pipes 65 and 66 are used to press the preform pipe 61 from both ends. However, the preform pipe 61 can be deformed without pressing the preform pipe 61 from both ends. Can do. In that case, instead of the pushers 65 and 66, a cylindrical seal block as a sealing member for sealing the cavity C is provided. When a high-pressure liquid is supplied into the preform pipe 61 via the liquid supply passages 71 and 72, the preform pipe 61 is bulged outward in the radial direction, and the preformed product housing portion 63 is supplied. Is pushed into the expanded pipe portion 64 and is pressed against the inner peripheral surface of the expanded pipe portion 64, and is pushed toward the center of the cavity C accordingly.

  By the way, when the volume of the expanded pipe 64 is large, the amount of the preform pipe 61 that enters the expanded pipe 64 increases. Therefore, it is necessary to increase the amount of push of the preform pipe 61 by the pushers 65 and 66. As the ejection progresses, the frictional resistance generated between the inner peripheral surface of the preformed product accommodation portion 63 and the outer peripheral surface of the preform pipe 61 increases, and the preform pipe 61 is pushed toward the center of the cavity C. It becomes difficult.

  However, in the present embodiment, a plurality of buckling deformed portions 20 are formed on the preform pipe 61 so as to protrude outward in the radial direction, so that the inner peripheral surface of the preformed product housing portion 63 and the preform are formed. The contact area with the outer peripheral surface of the pipe 61 can be reduced. Therefore, since the frictional resistance generated between the inner peripheral surface of the preformed product housing portion 63 and the outer peripheral surface of the preform pipe 61 can be reduced, the preform pipe 61 is caused to flow toward the center of the cavity C. In addition, when the preform pipe 61 is expanded into the expanded pipe portion 64 by supplying a high-pressure liquid, tension to draw the pipe 11 is generated. It is possible to sufficiently enter the expanded portion 64. As a result, the quality of the molded product can be improved.

  Further, when forming the molded product by deforming the preform pipe 61, each of the buckling deformed portions 20 needs to be completely erased from the surface of the molded product when the second step is completed. Whether or not the buckled deformed portion 20 is completely erased depends on tube material conditions such as the size of the cavity C, the diameter of the pipe 11, the thickness of the pipe 11, and the material of the pipe 11.

  Therefore, a height representing the optimum protrusion amount of the buckling deformed portion 20 is set in advance corresponding to the pipe material condition, and a target moving speed v1 corresponding to the height of the buckling deformed portion 20 is calculated in advance. The tube material condition and the target moving speed v1 are recorded in the storage device 81 or the like in correspondence with each other, and the buckling deformed portion 20 can be formed based on the recorded target moving speed v1.

  In that case, when the operator inputs the tube material condition by operating the operation unit 82, the compression processing means reads the target moving speed v1 corresponding to the tube material condition from the storage device 81, and in the primary molding apparatus 10 The chuck 12 is moved at the target moving speed v1.

  Therefore, when the optimal buckling deformation part 20 corresponding to the pipe material conditions is formed and the preform pipe 61 on which the buckling deformation part 20 is formed is deformed to form a molded product, the second step is completed. At the time, each of the buckling deformation portions 20 can be completely erased from the surface of the molded product, and the quality of the molded product can be improved.

  Moreover, since the buckling deformable portion 20 can be formed without using a mold apparatus in the first step, it is necessary to manage a gap between the mold apparatus and the pipe 11. Disappear. Therefore, the optimal buckling deformation part 20 corresponding to the pipe material conditions can be formed very easily.

  By the way, in the present embodiment, the preform pipe 61 is formed while moving the pipe 11 at a constant moving speed. However, the preform pipe 61 is formed by moving the pipe 11 intermittently. can do.

  In that case, while the pipe 11 is stationary, the heated portion is locally heated by the coil 14, and in this state, both ends of the pipe 11 are pressed with a predetermined force, thereby generating buckling deformation, The bending deformation part 20 is formed. Subsequently, the pipe 11 is moved by a predetermined distance, the next heated portion is locally heated, and in this state, both ends of the pipe 11 are pressed with a predetermined force to generate buckling deformation. The buckling deformation part 20 is formed. By repeating this operation, a preform pipe 61 having a plurality of buckling deformed portions 20 formed at predetermined intervals can be formed.

  Next, a second embodiment of the present invention in which the primary molding device 10 and the secondary molding device 50 are integrated will be described. In addition, about the thing which has the same structure as 1st Embodiment, the same code | symbol is provided and the effect of the same embodiment is used about the effect of the invention by having the same structure.

  FIG. 6 is a first diagram illustrating a hydroform molding method according to the second embodiment of the present invention, and FIG. 7 is a second diagram illustrating a hydroform molding method according to the second embodiment of the present invention. is there.

  In the figure, 91 is a pipe as a pipe material. In the first step, as shown in FIG. 6, the pipe 91 is set and processed in a mold apparatus 57, and as shown in FIG. A plurality of buckling deformation portions 20 as deformation portions having a predetermined height are formed at predetermined positions.

  Therefore, pushers 65 and 66 as first and second pressing portions are disposed at both ends of the pipe 91, and a semicircular shape is formed at a predetermined position of the lower mold 51 as the first mold. A coil 83 as a second heating body having a semicircular shape is disposed at a predetermined position of an upper mold 54 as a second mold. In addition, the coils 83 and 84 are disposed so as to face the heated portion set in the pipe 91.

  And the to-be-heated part of the pipe 91 is heated by the coils 83 and 84, the pipe 91 is pressed from both ends by the pushers 65 and 66, and the said buckling deformation part 20 is formed.

  In this way, a preform pipe 92 is formed as a preformed product in which the buckling deformed portion 20 is formed at a predetermined location.

  Subsequently, in the second step, when a liquid as a high-pressure molding medium is supplied into the preform pipe 92, the preform pipe 92 is bulged outward in the radial direction, and the molded product is molded. Is done.

  The present invention is not limited to the above embodiments, and various modifications can be made based on the gist of the present invention, and they are not excluded from the scope of the present invention.

11, 91 Pipe 20 Buckling deformation parts 61, 92 Preform pipe C Cavity

Claims (6)

(A) In the first step, a heated part set at a predetermined location of the pipe material is locally heated, the pipe material is pressed from both ends, and buckling deformation occurs in the heated part. Forming a hollow preform by forming a buckled deformation part,
(B) In the second step, a high-pressure molding medium is supplied into the preform, and the preform is molded by deforming the preform according to the inner shape of the cavity. Hydroform molding method.   In the first step, the tube material is gripped by the first and second gripping members at the gripping positions on the upstream side and the downstream side in the transport direction, and the moving speed of the first gripping member is set to the second gripping member. The hydrofoam molding method according to claim 1, wherein the pressing is performed by making the speed higher than the moving speed.   3. The height of the buckling deformed portion is changed in the first step by changing a speed difference between a moving speed of the first gripping member and a moving speed of the second gripping member. Hydroform molding method.   The hydroform molding method according to claim 1, wherein in the first step, the pipe material is pressed by a pressing portion disposed in a mold apparatus.   The said 2nd process WHEREIN: The said preforming part is pressed by the said press part, and is made to flow and push toward the center of a cavity with the tension | tensile_strength which arises by supplying a high pressure molding medium. Hydroform molding method. (A) a first mold including a plurality of heating elements disposed to face a plurality of heated parts set in the pipe material;
(B) A plurality of heating elements disposed so as to be able to contact with and separate from the first mold and disposed to face each of the heated parts, and the first mold when clamping A second mold forming a cavity between
(C) Disposed at both ends of the first and second molds, in the first step, the tube material set in the cavity is pressed from both ends and heated by the respective heating elements. A preformed product is formed by generating buckling deformation in the heated portion and forming a plurality of buckling deformed portions projecting radially outward . In the second step, the preform is formed from both ends. A pressing part for pressing and molding the molded product;
(D) having a molding medium introduction section for supplying a high-pressure molding medium into the preform molded in the cavity and deforming the preform according to the inner shape of the cavity; Hydroform molding equipment characterized by

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