Patent Publication Number: US-10773292-B2

Title: Forming device and forming method

Description:
RELATED APPLICATIONS 
     Priority is claimed to Japanese Patent Application No. 2015-167780, filed Aug. 27, 2015, and International Patent Application No. PCT/JP2016/075009, the entire content of each of which is incorporated herein by reference. 
     BACKGROUND 
     Technical Field 
     Certain embodiments of the present invention relate to a forming device and a forming method. 
     Description of Related Art 
     In the related art, as a forming device that performs forming of a metal pipe including a pipe portion and a flange portion, for example, a forming device illustrated in the related art is disclosed. The forming device disclosed in the related art includes a pair of upper die and lower die, and a gas supply unit that supplies a gas into a metal pipe material that is retained between the upper die and the lower die and is heated. When the upper die and the lower die are joined together, a first cavity portion (main cavity) in which the pipe portion is formed, and a second cavity portion (sub-cavity) which communicates with the first cavity portion and in which the flange portion is formed are constructed. In addition, in the forming device, the dies are closed, and a gas is supplied into the metal pipe material to expand the metal pipe material. According to this, it is possible to simultaneously form the pipe portion and the flange portion. 
     SUMMARY 
     According to an aspect of the invention, there is provided a forming device that forms a metal pipe including a pipe portion and a flange portion. The forming device includes: a gas supply unit that supplies a gas into a metal pipe material that is retained between a pair of first die and second die and is heated; a drive mechanism that moves at least one of the first die and the second die in a direction in which the dies are joined together; a first cavity portion in which the pipe portion is formed and a second cavity portion which communicates with the first cavity portion and in which the flange portion is formed, the first cavity portion and the second cavity portion being formed between the first die and the second die; a flange adjusting member which is capable of being advanced into the second cavity portion and is capable of being retreated from the second cavity portion, and which adjusts a length of the flange portion in an intersecting direction that is a direction intersecting an axial direction of the pipe portion; and a control unit that controls gas supply of the gas supply unit, driving of the drive mechanism, and advancing and retreating of the flange adjusting member. During forming of the metal pipe, the control unit sequentially performs a first control of allowing the flange adjusting member to be advanced into the second cavity portion, a second control of allowing the gas supply unit to supply a gas so as to temporarily form the flange portion of which a length is adjusted by the flange adjusting member, and a third control of allowing the flange adjusting member to be retreated from the second cavity portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic plan view of a forming device according to a first embodiment of the invention; 
         FIG. 2  is a schematic configuration diagram of the forming device; 
         FIGS. 3A to 3C  are enlarged views of the periphery of an electrode, and in the drawings,  FIG. 3A  is a view illustrating a state in which the electrode retains a metal pipe material,  FIG. 3B  is a view illustrating a state in which a sealing member abuts on the electrode, and  FIG. 3C  is a front view of the electrode; 
         FIG. 4  is a cross-sectional view of a blow-forming die which is taken along line IV-IV illustrated in  FIG. 2 ; 
         FIGS. 5A and 5B  are views illustrating manufacturing processes by the forming device, and in the drawings,  FIG. 5A  is a view illustrating a state in which the metal pipe material is set in a die, and  FIG. 5B  is a view illustrating a state in which the metal pipe material is retained by the electrode; 
         FIG. 6  is a view illustrating an overview of a blow-forming process by the forming device, and the subsequent flows; 
         FIGS. 7A to 7C  are views illustrating a specific forming aspect by an upper die and a lower die according to the first embodiment; 
         FIGS. 8A and 8B  are views illustrating a specific forming aspect by the upper die and the lower die according to the first embodiment; 
         FIGS. 9A to 9C  are views illustrating a specific forming aspect by the upper die and the lower die according to a modification example of the first embodiment; 
         FIGS. 10A to 10C  are views illustrating a specific forming aspect by the upper die and the lower die according to a second embodiment; 
         FIGS. 11A and 11B  are views illustrating a specific forming aspect by the upper die and the lower die according to the second embodiment; 
         FIGS. 12A to 12C  are views illustrating a specific forming aspect by the upper die and the lower die according to a third embodiment; and 
         FIGS. 13A and 13B  are views illustrating a specific forming aspect by the upper die and the lower die according to the third embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In the forming device, a protrusion, which is configured to prevent excessive expansion of a part of the metal pipe material that becomes the flange portion, is provided in the upper die. In this case, when forming the pipe portion and the flange portion, expansion of the flange portion is excessively controlled by the protrusion, and thus the flange portion may be bent in some cases. Accordingly, there is a problem that it is difficult to obtain a metal pipe having a desired shape. 
     On the other hand, in a case where the protrusion is not provided, a part of the metal pipe material, which becomes the flange portion, may be excessively expanded. In this case, the length of the flange portion in a direction, which is perpendicular to an axial direction of the pipe portion, excessively increases, and thus it is difficult to obtain a metal pipe having a desired shape. According to this, there are problems such as the thickness of the flange portion becomes too small, the flange portions become bent, and the thickness of the pipe portion becomes small. 
     It is desirable to provide a forming device and a forming method which are capable of easily forming a flange portion and a pipe portion which have a desired shape. 
     According to the forming device, it is possible to temporarily form the flange portion, of which a length is adjusted by the flange adjusting member, through the first control and the second control by the control unit. In addition, it is possible to retreat the flange adjusting member from the second cavity portion through the third control by the control unit. When performing main forming of the pipe portion and the flange portion after the third control, it is possible to adjust a length of the flange portion in the intersecting direction that is a direction intersecting an axial direction of the pipe portion in a satisfactory manner. In addition, the flange adjusting member does not exist in the second cavity portion during the main forming, and thus it is possible to suppress bending of the flange portion. As a result, it is possible to easily form the flange portion and the pipe portion having a desired shape. 
     In addition, the flange adjusting member may be advanced and retreated in the intersecting direction. In this case, it is possible to easily retreat the flange adjusting member to the outside of the die, and thus maintenance such as exchange of the flange adjusting member is simplified. In addition, the flange adjusting member is retreated to the outside of the die during the main forming of the metal pipe, and thus contact time between the flange portion kept at a high temperature and the flange adjusting member is shortened. According to this, deterioration of the flange adjusting member due to heat, and the like are suppressed. In addition, a position of the flange adjusting member in the second cavity portion can be easily changed, and thus it is possible to easily adjust the length of the flange portion. 
     In addition, the forming device may further include a suppressing member that abuts on the flange adjustment member during the second control by the control unit to hinder movement of the flange adjusting member in the intersecting direction. In this case, a position of the flange adjusting member is less likely to deviate during the temporary forming of the metal pipe material, and thus it is possible to improve adjustment accuracy of the length of the flange portion. 
     In addition, the flange adjusting member may be provided in a manner capable of being accommodated in at least one of the first die and the second die, and may be advanced and retreated in a direction in which the dies are joined together. In this case, supply of the metal pipe material into the forming device, and extraction of the metal pipe including the pipe portion and the flange portion from the forming device are not hindered by the flange adjusting member. 
     In addition, the first die may be an upper die, and the second die may be a lower die including a concave portion, the flange adjusting member, which is provided in a manner capable of being accommodated in the lower die, may include a base and a tip end on an upper die side in comparison to the base, a width of the tip end in the intersecting direction may be greater than a width of the base in the intersecting direction, and the tip end may be accommodated in the concave portion when the flange adjusting member is retreated. According to this, in a case where the flange adjusting member is accommodated in the lower die, positioning of the flange adjusting member becomes possible due to the tip end and the concave portion. Accordingly, since the shape of the tip end and the concave portion is determined, positioning of the flange adjusting member becomes easy when being retreated. 
     According to another aspect of the invention, there is provided a forming method of a metal pipe by using the forming device according to any one of the above-described paragraphs. The forming method includes: moving at least one of the first die and the second die in a direction in which the dies are joined together to form the first cavity portion and the second cavity portion between the first die and the second die; advancing the flange adjusting member into the second cavity portion; temporarily forming the pipe portion in the first cavity portion by supplying a gas into the metal pipe material that is located in the first cavity portion, and temporarily forming the flange portion of which a length is adjusted in the second cavity portion; retreating the flange adjusting member from the second cavity portion; and performing main forming of the pipe portion and the flange portion, which are temporarily formed, by moving at least one of the first die and the second die in a direction in which the dies are joined together. 
     According to the forming method, it is possible to temporarily form the flange portion, of which a length is adjusted by the flange adjusting member, in the second cavity portion. In addition, it is possible to perform main forming of the pipe portion and the flange portion after retreating the flange adjusting member from the second cavity portion. As described above, since the main forming of the pipe portion and the flange portion is performed after performing the temporary forming by using the flange adjustment member, it is possible to adjust the length of the flange portion in the intersecting direction that is a direction intersecting an axial direction of the pipe portion in a satisfactory manner. In addition, since the flange adjusting member does not exist in the second cavity portion during the main forming, it is possible to suppress bending of the flange portion. Accordingly, it is possible to easily form the flange portion and the pipe portion having a desired shape. 
     Hereinafter, description will be given of preferred embodiments of a forming device and a forming method according to the invention with reference to the accompanying drawings. Furthermore, in the drawings, the same reference numeral will be given to the same portion or an equivalent portion, and redundant description will not be repeated. 
     First, description will be given of a configuration of a forming device according to a first embodiment with reference to  FIG. 1  to  FIG. 4 . In this specification, the forming device represents a device configured to obtain a metal pipe having a desired shape by deforming a metal pipe material, which is supplied, into a desired shape by using a die. The metal pipe material represents a cylindrical member formed from a metal or an alloy, and the metal pipe represents a metal pipe material after being formed. Furthermore, in the following description, a metal pipe in temporary forming is referred to as a metal pipe  100  (refer to  FIG. 7C ), and a metal pipe after forming is referred to as a metal pipe  101  (refer to  FIG. 8B ). 
     &lt;Configuration of Forming Device&gt; 
       FIG. 1  is a schematic plan view of the forming device according to the first embodiment.  FIG. 2  is a schematic configuration diagram of the forming device. As illustrated in  FIG. 1  and  FIG. 2 , a forming device  10  includes a blow-forming die  13  including a pair of upper die (first die)  12  and lower die (second die)  11 , a drive mechanism  80  that moves at least one of the upper die  12  and the lower die  11 , a pipe retention mechanism  30  that retains a metal pipe material  14  between the upper die  12  and the lower die  11 , a heating mechanism  50  that electrically heats the metal pipe material  14  that is retained by the pipe retention mechanism  30 , a gas supply unit  60  that supplies a high-pressure gas (gas) into the metal pipe material  14  that is retained between the upper die  12  and the lower die  11  and is heated, a pair of gas supply mechanisms  40  and  40  which supplies the gas supplied from the gas supply unit  60  into the metal pipe material  14 , a pair of flange adjusting mechanisms  90  and  90  configured to adjust a length of a flange portion  100   b  of the metal pipe  100 , and a water circulation mechanism  72  that forcibly cools down the blow-forming die  13  with water. In addition, the forming device  10  includes a control unit  70  that controls driving of the drive mechanism  80 , driving of the pipe retention mechanism  30 , driving of the heating mechanism  50 , gas supply from the gas supply unit  60 , and driving of the pair of flange adjusting mechanisms  90  and  90 . 
     As illustrated in  FIG. 1 , the blow-forming die  13 , the drive mechanism  80 , the pipe retention mechanism  30 , the heating mechanism  50 , the water circulation mechanism  72 , and the control unit  70  constitute a main body M of the forming device  10 . In addition, in a plan view, the pair of gas supply mechanisms  40  and  40  and the pair of flange adjusting mechanisms  90  and  90  are provided with the main body M interposed therebetween. The gas supply unit  60 , which is connected to the gas supply mechanisms  40  and  40 , is disposed to be spaced apart from the main body M, and the like. A wall may be provided between the gas supply unit  60  and the main body M. 
     In the following description, directions perpendicular to each other in a plan view are set as a direction X and a direction Y, respectively. The direction X is referred to as a right and left direction, and the direction Y is referred to as a front and rear direction for convenience. In addition, a direction perpendicular to the direction X and the direction Y is set as a direction Z, and the direction Z is referred to as an upper and lower direction for convenience. As illustrated in  FIG. 1 , in a plan view, the pair of gas supply mechanisms  40  and  40  is disposed along the direction X with the forming device  10  interposed therebetween, and the pair of flange adjusting mechanisms  90  and  90  is disposed along the direction Y with the forming device  10  interposed therebetween. The metal pipe material  14  is disposed inside the main body M in a state in which an axial direction thereof conforms to the direction X. Accordingly, the direction Y and the direction Z may also be referred to as a direction intersecting an axial direction of the metal pipe material  14  and the metal pipe  100  or  101 . In this embodiment, the direction Y may be referred to as an intersecting direction. 
     As illustrated in  FIG. 2 , the lower die  11  that is one side of the blow-forming die  13  is fixed to a base stage  15 . The lower die  11  is constituted by a large steel block, and includes a rectangular cavity surface  16  on an upper surface thereof. A cooling water passage  19  is formed in the lower die  11 , and a thermocouple  21 , which is inserted from a lower side of approximately the center of the lower die  11 , is provided in the lower die  11 . The thermocouple  21  is supported by a spring  22  in a vertically movable manner. In addition, a space  11   a  is provided in the vicinity of right and left ends of the lower die  11 . In the space  11   a , the following electrodes  17  and  18  (lower electrodes), which are movable portions of the pipe retention mechanism  30 , and the like are disposed in the space  11   a  in a manner capable of being vertically advanced and retreated by an actuator (not illustrated). An insulating material I 1  for prevention of electrification is provided between the lower die  11  and the lower electrode  17  and on a lower side of the lower electrode  17 , and between the lower die  11  and the lower electrode  18  and on a lower side of the lower electrode  18 , respectively. The insulating material I 1  is fixed by the actuator in the same manner as the lower electrodes  17  and  18 . 
     The lower electrodes  17  and  18  can support the metal pipe material  14  in a manner capable of elevating the metal pipe material  14  between the upper die  12  and the lower die  11 . In addition, the thermocouple  21  only illustrates an example of temperature measuring means, and may be a non-contact type temperature sensor such as a radiation thermometer and an optical thermometer. Furthermore, it is possible to employ a configuration in which the temperature measuring means is omitted as long as a correlation between electrification time and a temperature can be obtained. 
     The upper die  12  that is the other side of the blow-forming die  13  is fixed to the following slide  82  that constitutes the drive mechanism  80 . The upper die  12  is constituted by a large steel block. A cooling water passage  25  is formed inside the upper die  12 , and a rectangular cavity surface  24  is provided on a lower surface of the upper die  12 . The cavity surface  24  is provided at a position that faces the cavity surface  16  of the lower die  11 . In the same manner as in the lower die  11 , a space  12   a  is provided in the vicinity of right and left ends of the upper die  12 , and the following electrodes  17  and  18  (upper electrodes), which are movable portions of the pipe retention mechanism  30 , and the like are disposed in the space  12   a  in a manner capable of being vertically advanced and retreated by the actuator (not illustrated). An insulating material  12  for prevention of electrification is provided between the upper die  12  and the upper electrode  17  and on an upper side of the upper electrode  17 , and between the upper die  12  and the upper electrode  18  and on an upper side of the upper electrode  18 , respectively. The insulating material  12  is fixed by the actuator in the same manner as in the upper electrodes  17  and  18 . 
     At a right portion of the pipe retention mechanism  30 , a semicircular arc shaped concave groove  18   a , which corresponds to an outer peripheral surface of the metal pipe material  14 , is formed in each of the surfaces, which face each other, of the electrodes  18  and  18  (refer to  FIG. 3C ), and the concave grooves  18   a  have a configuration on which the metal pipe material  14  can be placed for accurate insertion into the concave grooves  18   a . At a right portion of the pipe retention mechanism  30 , a semicircular arc shaped groove (not illustrated), which corresponds to the outer peripheral surface of the metal pipe material  14 , is formed in the exposed surfaces, which face each other, of the insulating materials I 1  and I 2  in the same manner as in the concave groove  18   a . In addition, a tapered concave surface  18   b , of which the periphery is inclined and recessed in a tapered shape toward the concave groove  18   a , is formed in the front surfaces (surfaces of the dies in an outward direction) of the electrodes  18 . Accordingly, when the metal pipe material  14  is interposed from the upper and lower direction at the right portion of the pipe retention mechanism  30 , it is possible to accurately surround the outer periphery of a right end of the metal pipe material  14  in a close contact manner over the entirety of the periphery. 
     At a left portion of the pipe retention mechanism  30 , a semicircular arc shaped concave groove  17   a , which corresponds to the outer peripheral surface of the metal pipe material  14 , is formed in each of the surfaces, which face each other, of the electrodes  17  and  17  (refer to  FIG. 3C ), and the concave grooves  17   a  have a configuration on which the metal pipe material  14  can be placed for accurate insertion into portions of the concave grooves  17   a . At a left portion of the pipe retention mechanism  30 , a semicircular arc shaped groove (not illustrated), which corresponds to the outer peripheral surface of the metal pipe material  14 , is formed in the exposed surfaces, which face each other, of the insulating materials I 1  and I 2  in the same manner as in the concave groove  18   a . In addition, a tapered concave surface  17   b , of which the periphery is inclined and recessed in a tapered shape toward the concave groove  17   a , is formed in the front surfaces (surfaces of the dies in an outward direction) of the electrodes  17 . Accordingly, when the metal pipe material  14  is interposed from the upper and lower direction at the left portion of the pipe retention mechanism  30 , it is possible to accurately surround the outer periphery of a left end of the metal pipe material  14  in a close contact manner over the entirety of the periphery. 
     Each of the pair of gas supply mechanisms  40  and  40  includes a cylinder unit  42 , a cylinder rod  43  that is advanced and retreated in accordance with an operation of the cylinder unit  42 , and a sealing member  44  that is connected to a front end of the cylinder rod  43  on a pipe retention mechanism  30  side. The cylinder unit  42  is placed on and fixed to the base stage  15  through a block  41 . A tapered surface  45  is formed at the front end of the sealing member  44  to be tapered. The tapered surface  45  on one side is configured in a shape capable of being accurately fitted into and abutting with the tapered concave surface  18   b  of each of the electrodes  18  (refer to  FIG. 3B ). Similarly, the tapered surface  45  on the other side is configured in a shape capable of being accurately fitted into and abutting with the tapered concave surface  17   b  of each of the electrodes  17 . The sealing member  44  is provided with a gas passage  46  which extends from the cylinder unit  42  side toward a front end as specifically illustrated in  FIGS. 3A and 3B , and through which a high-pressure gas supplied from the gas supply unit  60  flows. The gas passage  46  can communicate with the inside of the metal pipe material  14  that is placed on an inner side of the forming device  10 . 
     The gas supply unit  60  includes a gas source  61 , an accumulator  62  that stores a gas supplied by the gas source  61 , a first tube  63  that extends from the accumulator  62  to the cylinder unit  42  of the gas supply mechanism  40 , a pressure control value  64  and a switching valve  65  which are provided in the first tube  63 , a second tube  67  that extends from the accumulator  62  to the gas passage  46  formed in the sealing member  44 , and a pressure control valve  68  and a check valve  69  which are provided in the second tube  67 . The pressure control valve  64  plays a role of supplying a gas, which is maintained at an operation pressure adapted to a pressure applied to the metal pipe material  14  by the sealing member  44 , to the cylinder unit  42 . The check valve  69  plays a role of preventing a high-pressure gas from flowing backward in the second tube  67 . Furthermore, the second tube  67  may be provided with a filter through which a specific gas is transmitted, or a filter through which a specific gas is not transmitted. For example, when the second tube  67  is provided with a filter through which only nitrogen is transmitted or a filter through which a gas such as oxygen that oxidizes a metal is not transmitted, occurrence of scales in the metal pipe  100  or  101  is suppressed. 
     The pressure control valve  64  plays a role of supplying a high-pressure gas, which is maintained at an operation pressure adapted to a pressure required from the sealing member  44  side, to the cylinder unit  42 . The pressure control valve  68  plays a role of supplying a high-pressure gas maintained at a desired pressure to the metal pipe material  14  through the gas passage  46 . The pressure control valves  64  and  68 , the switching valve  65 , the check valve  69 , and the like are controlled by the control unit  70 . 
     The heating mechanism  50  includes a power supply  51 , a lead wire  52  that extends from the power supply  51  and is connected to each of the electrodes  17  and  18 , and a switch  53  that is provided in the lead wire  52 . 
     The drive mechanism  80  includes a slide  82  that fixes the upper die  12 , a driving unit  81  that generates a driving force for moving the slide  82 , and a servomotor  83  that controls a fluid amount with respect to the driving unit  81 . The driving unit  81  is constituted by a fluid supply unit that supplies a fluid (operation oil in a case of employing a hydraulic cylinder as the press cylinder  26 ) for driving a press cylinder  26  to the press cylinder  26 . The slide  82  moves the upper die  12  through the operation of the driving unit  81  and the servomotor  83  so that the upper die  12  and the lower die  11  are joined to each other. The slide  82  is configured to be suspended to the press cylinder  26 , and is guided by a guide cylinder  27  so as not to transversally vibrate. 
     Furthermore, the driving unit  81  is not limited to the configuration of applying a driving force to the slide  82  through the press cylinder  26  as described above, and may employ, for example, a configuration in which a driving unit is mechanically connected to the slide  82  so as to directly or indirectly apply a driving force generated by the servomotor  83  to the slide  82 . For example, it may employ a drive mechanism including an eccentric shaft (or an eccentric crank), a driving source (for example, a servomotor, a reduction gear, and the like) that applies a rotational force for rotating the eccentric shaft, a converting unit (for example, a connecting rod, an eccentric sleeve, and the like) that converts a rotary motion of the eccentric shaft into a linear motion to move the slide. Furthermore, in this embodiment, the driving unit  81  may not include the servomotor  83 . 
       FIG. 4  is a cross-sectional view taken along line IV-IV in  FIG. 2 , and is a schematic cross-sectional view when the blow-forming die  13  is seen from a lateral surface direction. As illustrated in  FIG. 4 , the cavity surface  16  is formed in the upper surface of the lower die  11 , and the cavity surface  24 , which faces the cavity surface  16  of the lower die  11 , is formed in the lower surface of the upper die  12 . When the cavity surfaces  16  and  24  are combined with each other, a main cavity portion (first cavity portion) MC that is a rectangular space is formed. In addition, a sub-cavity portion (second cavity portion) SC is formed between the lower die  11  and the upper die  12  to communicate with the main cavity portion MC. The sub-cavity portion SC is formed on both sides of the main cavity portion MC in the direction Y. 
     Flange adjusting members  91  and  92  configured to adjust a length of the flange portion  100   b  of the metal pipe  100  are disposed in the sub-cavity portion SC. The flange adjusting members  91  and  92  are plate-shaped members which face each other along the direction Y and are formed from a metal, an alloy, or ceramic. In the flange adjusting members  91  and  92 , a side along the direction X is the longest side and has an approximately rectangular parallelepiped shape. For example, the length of the flange adjusting members  91  and  92  along the direction X is set to approximately the same length as that of the metal pipe material  14 , or a length less than that of the metal pipe material  14 . In addition, the thickness of the flange adjusting members  91  and  92  in the upper and lower direction (thickness along the direction Z) is set to be smaller than the diameter of the metal pipe material  14 . 
     The flange adjusting member  91  is attached to the flange adjusting mechanism  90  on one side through a rod  93 , and can be located in the sub-cavity portion SC on a front side of the main cavity portion MC. In this embodiment, a surface  91   a  of the flange adjusting member  91  on the rod  93  side is flush with or approximately flush with surfaces of the lower die  11  and the upper die  12  on the rod  93  side, but there is no limitation thereto. The flange adjusting member  91  is capable of being advanced and retreated along the direction Y by the actuator (not illustrated) provided inside the flange adjusting mechanism  90  on one side. In  FIG. 4 , the flange adjusting member  91  is disposed in the sub-cavity portion SC, and a distance of the flange adjusting member  91  and the main cavity portion MC along the direction Y is adjusted to be shorter than a length of a flange portion  101   b  that is finally formed. Furthermore, the flange adjusting member  91  can be retreated to the outside of the sub-cavity portion SC. That is, the flange adjusting member  91  can move to a front side in the direction Y in comparison to the sub-cavity portion SC. 
     The flange adjusting member  92  is attached to the flange adjusting mechanism  90  on the other side through a rod  94 , and can be located in the sub-cavity portion SC on a rear side of the main cavity portion MC. In this embodiment, a surface  92   a  of the flange adjusting member  92  on the rod  94  side is flush with or approximately flush with surfaces of the lower die  11  and the upper die  12  on the rod  94  side, but there is no limitation thereto. The flange adjusting member  92  is capable of being advanced and retreated along the direction Y by the actuator (not illustrated) provided inside the flange adjusting mechanism  90  on the other side. In a case where the flange adjusting member  92  is disposed in the sub-cavity portion SC, a distance of the flange adjusting member  92  and the main cavity portion MC along the direction Y is adjusted to be shorter than the length of the flange portion  101   b  that is finally formed. Furthermore, the flange adjusting member  92  can be retreated to the outside of the sub-cavity portion SC similar to the flange adjusting member  91 . That is, the flange adjusting member  92  can move to a rear side in the direction Y in comparison to the sub-cavity portion SC. 
     The control unit  70  can supply a high-pressure gas into the metal pipe material  14  by controlling the pair of gas supply mechanisms  40  and  40 , and the gas supply unit  60 . The control unit  70  can control temporary forming and forming of the metal pipe material  14  by controlling supply of the high-pressure gas. Here, the control of supply of the high-pressure gas represents control of a pressure of the high-pressure gas, supply time or a supply amount of the high-pressure gas, and control of supply timing of the high-pressure gas. The control unit  70  can heat the metal pipe material  14  to a quenching temperature (AC3 transformation point or higher) by controlling the heating mechanism  50 . The control unit  70  controls the servomotor  83  of the driving unit  81  to control the amount of a fluid to be supplied to the press cylinder  26 . According to this, the control unit  70  can control movement of the slide  82 . In addition, when information from (A) illustrated in  FIG. 2  is transmitted to the control unit  70 , the control unit  70  acquires temperature information from the thermocouple  21 , and controls the press cylinder  26 , the switch  53 , and the like. 
     In addition, the control unit  70  can advance the flange adjusting members  91  and  92  into the sub-cavity portion SC formed by the blow-forming die  13  and can retreat the flange adjusting members  91  and  92  from the sub-cavity portion SC by controlling the pair of flange adjusting mechanisms  90 . 
     The water circulation mechanism  72  includes a water tank  73  that stores water, a water pump  74  that pumps up the water stored in the water tank  73  and pressurizes the water to deliver the pressurized water to the cooling water passage  19  of the lower die  11  and the cooling water passage  25  of the upper die  12 , and a pipeline  75 . Although not illustrated, a cooling tower that lowers a water temperature or a filter that purifies water may be interposed in the pipeline  75 . 
     &lt;Method of Forming Metal Pipe by Using Forming Device&gt; 
     Next, description will be given of a method of forming the metal pipe by using the forming device  10 . First, an overview of the method of forming the metal pipe material  14  will be described with reference to  FIGS. 5A and 5B , and  FIG. 6 .  FIGS. 5A and 5B  illustrate from a pipe injection process of injecting the metal pipe material  14  as a material to an electrical heating process of electrically heating the metal pipe material  14 . First, the metal pipe material  14  as quenchable steel species is prepared. In this embodiment, a metal pipe material made of steel is prepared. As illustrated in  FIG. 5A , for example, the metal pipe material  14  is placed (injected) on the electrodes  17  and  18 , which are provided on the lower die  11  side, by using a robot arm and the like. Since the concave groove  17   a  is formed in the electrode  17  and the concave groove  18   a  is formed in the electrode  18 , positioning of the metal pipe material  14  is attained by the concave grooves  17   a  and  18   a.    
     Next, the control unit  70  controls the pipe retention mechanism  30  to retain the metal pipe material  14  by the pipe retention mechanism  30 . Specifically, as illustrated in  FIG. 5B , the actuator (not illustrated), which can advance and retreat the electrodes  17  and  18 , is allowed to operate so as to make the electrodes  17  and  18  on an upper side and the electrodes  17  and  18  on a lower side, approach each other and abut with each other. Through the abutting, both ends of the metal pipe material  14  are pinched by the electrodes  17  and  18  from upper and lower sides. In addition, the pinching is performed in an aspect in which the electrodes  17  and  18  come into close contact with the entire periphery of the metal pipe material  14  due to the presence of the concave groove  17   a  formed in the electrodes  17 , the concave groove  18   a  formed in the electrodes  18 , and the concave groove provided in the insulating materials I 1  and I 2 . However, the electrodes  17  and  18  may abut with a part of the metal pipe material  14  in a peripheral direction without limitation to the close contact configuration over the entire periphery of the metal pipe material  14 . 
     As illustrated in  FIG. 5B , the control unit  70  controls the heating mechanism  50  to heat the metal pipe material  14 . Specifically, the control unit  70  turns on the switch  53  of the heating mechanism  50 . In this state, power from the power supply  51  is supplied to the electrodes  17  and  18  which pinch the metal pipe material  14 , and the metal pipe material  14  generates heat due to resistance that exists in the metal pipe material  14  (Joule&#39;s heat). At this time, a measurement value of the thermocouple  21  is always monitored, and electrification is controlled on the basis of the result. 
       FIG. 6  illustrates an overview of the blow-forming process by the forming device and the subsequent flow. As illustrated in  FIG. 6 , with respect to the metal pipe material  14  after heating, the blow-forming die  13  is moved to be closed, and the metal pipe material  14  is disposed in the main cavity portion MC of the blow-forming die  13 . Before movement of the blow-forming die  13 , the flange adjusting members  91  and  92  are moved into the sub-cavity portion SC (details thereof will be described later). Then, both ends of the metal pipe material  14  are sealed with the sealing member  44  by operating the cylinder unit  42  of the gas supply mechanism  40  (also refer to  FIGS. 3A and 3B ). According to this, the metal pipe material  14  is hermetically sealed by the blow-forming die  13 , the flange adjusting members  91  and  92 , and the sealing member  44 . After hermetically sealing the metal pipe material  14 , a gas is blown into the metal pipe material  14 , and temporarily forms the metal pipe material  14 , which is softened due to heating, to conform to a shape of the cavity. After the temporary forming, the flange adjusting members  91  and  92  are retreated from the sub-cavity portion SC through a control of the control unit  70 . After the flange adjusting members  91  and  92  are retreated, the blow-forming die  13  is closed and a gas is supplied again, thereby performing forming (main forming) of the metal pipe  100 . 
     The metal pipe material  14  is heated to a high temperature (approximately 950° C.) and is softened, and thus the gas supplied into the metal pipe material  14  thermally expands. According to this, for example, when the gas that is supplied is set as a compressed air, the metal pipe material  14  maintained at 950° C. is easily expanded due to the compressed air that thermally expands, and thus it is possible to obtain the metal pipe  100  or  101 . 
     An outer peripheral surface of the metal pipe material  14 , which is blow-formed and expanded, comes into contact with the cavity surface  16  of the lower die  11  and is rapidly cooled down, and the outer peripheral surface comes into contact with the cavity surface  24  of the upper die  12  and is rapidly cooled down (the upper die  12  and the lower die  11  have large thermal capacity and are managed at a low temperature, and thus when the metal pipe material  14  comes into contact with the dies, heat on a pipe surface is transferred to the die side at a time). Accordingly, quenching is performed. The cooling method as described above is called die contact cooling or die cooling. Immediately after being quickly cooled down, austenite is transformed into martensite (hereinafter, transformation of austenite to martensite is referred to as “martensite transformation”). In a second half of the cooling, a cooling rate is reduced, and thus martensite is transformed into other structures (troostite, sorbite, and the like) due to recovered heat. Accordingly, it is not necessary to separately perform a tempering treatment. In addition, in this embodiment, instead of or in addition to the die cooling, cooling may be performed by supplying a cooling medium to the metal pipe  101 . For example, cooling may be performed by bringing the metal pipe material  14  into contact with the dies (the upper die  12  and the lower die  11 ) up to a temperature at which martensite transformation initiate, and then the dies may be opened and the cooling medium (cooling gas) may be blown to the metal pipe material  14  to cause the martensite transformation to occur. 
     Next, an example of a specific forming aspect by the upper die  12  and the lower die  11  will be described in detail with reference to  FIGS. 7A to 7C , and  FIGS. 8A and 8B . As illustrated in  FIG. 7A , the metal pipe material  14  is retained between the upper die  12  and the lower die  11  and on the cavity surface  16 . In addition, the flange adjusting members  91  and  92  are moved along the direction Y to advance the flange adjusting members  91  and  92  into the sub-cavity portion SC through a control (first control) of the control unit  70 . After movement of the flange adjusting members  91  and  92 , the upper die  12  is moved to approach the lower die  11  by using the drive mechanism  80 , and the upper die  12  and the flange adjusting members  91  and  92  are brought into contact with each other. According to this, as illustrated in  FIG. 7B , when seen from the direction X, the metal pipe material  14  is hermetically sealed by the lower die  11 , the upper die  12 , and the flange adjusting members  91  and  92 . A space in which the metal pipe material  14  is hermetically sealed is formed by the main cavity portion MC, and the sub-cavity portion SC that is narrowed by the flange adjusting members  91  and  92 . 
     Next, a gas is injected into the metal pipe material  14  by the gas supply mechanism  40  and the gas supply unit  60  through a control (second control) of the control unit  70 . As illustrated in  FIG. 7C , the metal pipe material  14 , which is softened through heating by the heating mechanism  50  and into which a high-pressure gas is injected, expands in the main cavity portion MC, and enters the sub-cavity portion SC that communicates with the main cavity portion MC and expands therein. According to this, the metal pipe material  14  is temporarily formed, and becomes the metal pipe  100 . The pipe portion  100   a  of the metal pipe  100  is temporarily formed in the main cavity portion MC, and the flange portion  100   b  of the metal pipe  100  is temporarily formed in the sub-cavity portion SC. A length of the temporarily formed flange portion  100   b  along the direction Y is adjusted in accordance with the position of the flange adjusting members  91  and  92  in the sub-cavity portion SC. Specifically, as a distance between the main cavity portion MC and the flange adjusting members  91  and  92  in the direction Y is shortened, a length of the flange portion  100   b  along the direction Y is shortened. In addition, as the distance between the main cavity portion MC and the flange adjusting members  91  and  92  in the direction Y is extended, the length of the direction of the flange portion  100   b  along the direction Y is extended. 
     In the example illustrated in  FIG. 7C , the main cavity portion MC is configured to have a rectangular cross-sectional shape, and thus when the metal pipe material  14  is blow-formed in accordance with the shape, the pipe portion  100   a  is temporarily formed into a rectangular tubular shape. However, the shape of the main cavity portion MC is not particularly limited, and various shapes such as circular cross-sectional shape, an elliptical cross-sectional shape, and a polygonal cross-sectional shape may be employed in accordance with a desired shape. 
     Next, as illustrated in  FIG. 8A , the flange adjusting members  91  and  92  are retreated from the sub-cavity portion SC through a control (third control) by the control unit  70 . According to this, the upper die  12  can be further moved to the lower die  11  side. At this time, gas supply by the gas supply unit  60  is temporarily stopped so that the shape of the pipe portion  100   a  and the flange portion  100   b  does not vary. 
     Next, as illustrated in  FIG. 8B , the upper die  12  is further moved to the lower die  11  side by the drive mechanism  80  through a control (fourth control) by the control unit  70 , and gas supply by the gas supply unit  60  is restarted, thereby main forming of the temporarily formed metal pipe  100  is performed. In the main forming, the pipe portion  100   a  and the flange portion  100   b  of the metal pipe  100  are compressed by the lower die  11  and the upper die  12 , thereby forming the metal pipe  101  including a pipe portion  101   a  and a flange portion  101   b . When compressing the metal pipe  100 , a gas is supplied into the pipe portion  100   a  by the gas supply unit  60 . Accordingly, it is possible to suppress a part of the compressed flange portion  101   b  from intruding into the main cavity portion MC side, and it is possible to complete the metal pipe  101  that is not bent and twisted. Furthermore, time from the blow forming of the metal pipe material  14  to completion of forming of the metal pipe  101  also depends on the kind of the metal pipe material  14 , but it takes approximately several seconds to several tens of seconds. 
     As described above, according to the method of forming the metal pipe  101  by using the forming device  10  according to this embodiment, it is possible to temporarily form the flange portion  100   b  of which a length is adjusted by the flange adjusting members  91  and  92  through the first control and the second control of the control unit  70 . In addition, it is possible to retreat the flange adjusting members  91  and  92  from the sub-cavity portion SC through the third control of the control unit  70 . The main forming of the pipe portion  100   a  and the flange portion  100   b  is performed after the third control, and thus it is possible to adjust the length of the flange portion  101   b  in a direction (that is, the direction Y) intersecting an axial direction of the pipe portion  101   a  in the metal pipe  101  after the main forming in a satisfactory manner. In addition, since the flange adjusting members  91  and  92  do not exist in the sub-cavity portion SC in the main forming, it is possible to suppress bending of the flange portion  101   b . As a result, according to this embodiment, it is possible to easily form the flange portion  101   b  and the pipe portion  101   a  which have a desired shape. 
     In addition, the flange adjusting members  91  and  92  are advanced and retreated in a direction along the length of the flange portion  101   b . In this case, the flange adjusting members  91  and  92  can be easily retreated to the outside of the blow-forming die  13 , and thus maintenance such as exchange of the flange adjusting members  91  and  92  is simplified. In addition, in the main forming of the metal pipe  100 , the flange adjusting members  91  and  92  are retreated to the outside of the blow-forming die  13 , and thus contact time between the flange portion  100   b  maintained at a high temperature and the flange adjusting members  91  and  92  is shortened. According to this, deterioration of the flange adjusting members  91  and  92  due to heat, and the like are suppressed. In addition, it is possible to easily change the position of the flange adjusting members  91  and  92  in the sub-cavity portion SC, and thus it is possible to easily adjust the length of the flange portion  101   b  along the direction Y. 
     Next, description will be given of a modification example of the first embodiment with reference to  FIG. 9A to 9C . In this modification example, as illustrated in  FIGS. 9A to 9C , a forming device includes a suppressing member  111  that abuts on the surface  91   a  of the flange adjusting member  91  on the rod  93  side to hinder movement of the flange adjusting member  91  in the direction Y, a suppressing member  112  that abuts on the surface  92   a  of the flange adjusting member  92  on the rod  94  side to hinder movement of the flange adjusting member  92  in the direction Y, a pair of fixing members  113   a  and  113   b  which are located on a further rod  93  side in comparison to the suppressing member  111  in the direction Y to hinder movement of the suppressing member  111  in the direction Y, and a pair of fixing members  114   a  and  114   b  which are located on a further rod  94  side in comparison to the suppressing member  112  in the direction Y to hinder movement of the suppressing member  111  in the direction Y. 
     The suppressing members  111  and  112  are approximately plate-shaped members which can move along the direction Z and are formed from a metal, an alloy, or ceramic. As illustrated in  FIG. 9C , a U-shaped groove  111   a  when seen from a lateral surface is provided in the suppressing member  111 . The groove  111   a  is provided in the suppressing member  111  in correspondence with the number and the position of the rod  93 , and the rod  93  can be inserted into the groove  111   a . In this modification example, two grooves  111   a  are provided in correspondence with the position and the number of the rod  93  that is mounted to the flange adjusting member  91 . A groove corresponding to the position and the number of the rod  93  that is mounted to the flange adjusting member  91  is provided in the suppressing member  112  in the same manner as in the suppressing member  111 . 
     The pair of fixing members  113   a  and  113   b  are spaced apart from each other in the direction Z, and are disposed not to hinder movement of the flange adjusting member  91  and the rod  93 . In the direction Z, the fixing member  113   a  is located on a further upper die  12  side in comparison to the flange adjusting member  91 , and the fixing member  113   b  is located on a further lower die  11  side in comparison to the flange adjusting member  91 . Similarly, the pair of fixing members  114   a  and  114   b  are spaced apart from each other in the direction Z and are disposed not to hinder movement of the flange adjusting member  92  and the rod  94 . In the direction Z, the fixing member  114   a  is located on a further upper die  12  side in comparison to the flange adjusting member  92 , and the fixing member  114   b  is located on a further lower die  11  side in comparison to the flange adjusting member  92 . Each of the fixing members  113   a ,  113   b ,  114   a , and  114   b  has a flat plate shape, but may have an arbitrary shape without limitation thereto. 
     Hereinafter, an example of a specific forming aspect by the upper die  12  and the lower die  11  according to this modification example will be described in detail. First, as illustrated in  FIG. 9A , after the metal pipe material  14  is hermetically sealed by the lower die  11 , the upper die  12 , and the flange adjusting members  91  and  92  when seen from the direction X, the suppressing member  111  is moved to an upper side along the direction Z, and is fixed at a position at which the suppressing member  111  abuts on the surface  91   a  of the flange adjusting member  91  on the rod  93  side. At this time, the rod  93  is located in the groove  111   a , and thus movement of the suppressing member  111  is not hindered by the rod  93 . Similarly, the suppressing member  112  is moved to the load  94  side along the direction Z, and is fixed at a position at which the suppressing member  112  abuts on the surface  92   a  of the flange adjusting member  92  on the rod  94  side. After fixing the suppressing members  111  and  112 , a gas is injected into the metal pipe material  14  by the gas supply mechanism  40  and the gas supply unit  60  through the second control of the control unit  70 , and the metal pipe material  14  is temporarily formed into the metal pipe  100 . 
     Next, as illustrated in  FIGS. 9B and 9C , gas supply by the gas supply unit  60  is temporarily stopped, and then the suppressing members  111  and  112  are moved to a lower side along the direction Z. According to this, abutting between the suppressing member  111  and the flange adjusting member  91  is released, and abutting between the suppressing member  112  and the flange adjusting member  92  is released. In addition, the flange adjusting members  91  and  92  are retreated from the sub-cavity portion SC through a control by the control unit  70 . After the flange adjusting members  91  and  92  are retreated, main forming is performed with respect to the metal pipe  100  in the same manner as in the first embodiment. 
     According to the modification example, the forming device  10  includes the suppressing member  111  that is fixed at a position at which the suppressing member  111  abuts on the surface  91   a  of the flange adjusting member  91  during the second control by the control unit  70 , and includes the suppressing member  112  that is fixed at a position at which the suppressing member  112  abuts on the surface  92   a  of the flange adjusting member  92 . In the temporary forming of the metal pipe material  14 , the flange adjusting members  91  and  92  may be pressed toward the outside of the sub-cavity portion SC due to a pressure of the gas that is supplied into the metal pipe material  14 . However, in this modification example, the suppressing members  111  and  112  can suppress movement of the flange adjusting members  91  and  92  to the outside of the sub-cavity portion SC along the direction Y. As a result, according to this modification example, in addition to the operational effect exhibited by the first embodiment, the position of the flange adjusting members  91  and  92  is less likely to deviate during temporary forming of the metal pipe material  14 , and thus it is possible to improve adjustment accuracy of the length of the flange portion  100   b  that is temporarily formed. 
     Furthermore, in this modification example, the surface  91   a  of the flange adjusting member  91  on the rod  93  side is flush with the surfaces of the lower die  11  and the upper die  12  on the rod  93  side. According to this, a step difference is not formed between the surface  91   a  and the surfaces of the lower die  11  and the upper die  12  on the rod  93  side, and thus movement of the suppressing member  111  is not hindered. According to this, breakage of the lower die  11 , the upper die  12 , the flange adjusting member  91 , and the suppressing member  111  is suppressed. Similarly, the surface  92   a  of the flange adjusting member  92  on the rod  94  side is flush with the surfaces of the lower die  11  and the upper die  12  on the rod  94  side. According to this, movement of the suppressing member  112  is not hindered, and thus breakage of the lower die  11 , the upper die  12 , the flange adjusting member  92 , and the suppressing member  112  is suppressed. 
     Next, description will be given of a forming device according to a second embodiment with reference to  FIGS. 10A to 10C , and  FIGS. 11A and 11B . As illustrated in  FIG. 10A , in the second embodiment, an upper die  12 A, which is provided with holes  12   b  and  12   c  which extend along the direction Z, is used differently from the first embodiment. The holes  12   b  and  12   c  are provided with the main cavity portion MC interposed therebetween in the direction Y. The hole  12   b  and the main cavity portion MC are spaced apart from each other by a predetermined distance in the direction Y, and the hole  12   c  and the main cavity portion MC are spaced apart from each other by a predetermined distance in the direction Y. A flange adjusting member  191  is accommodated in the hole  12   b , and a flange adjusting member  192  is accommodated in the hole  12   c . In other words, the flange adjusting members  191  and  192  are provided in a manner capable of being accommodated in the upper die  12 A. 
     The flange adjusting members  191  and  192  are members which are formed from a metal or an alloy which move along the direction Z in a manner capable of being advanced and retreated in the sub-cavity portion SC, and examples thereof include a piston. The flange adjusting members  191  and  192  are approximately rectangular parallelepiped plate-shaped members which extend along the direction X. A length of the flange adjusting members  191  and  192  along the direction X is shorter than the length of the metal pipe material  14 , and is equal to or less than the length of the upper die  12 A along the direction X. An upper end of the flange adjusting member  191  and an upper end of the flange adjusting member  192  are attached to a flange adjusting mechanism (not illustrated). The flange adjusting members  191  and  192  are moved to be advanced into the sub-cavity portion SC, and are moved to be retreated from the sub-cavity portion SC by the flange adjusting mechanism. For example, the flange adjusting mechanism according to the second embodiment is provided in the main body M such as an upper side of the slide  82  (refer to  FIGS. 1 and 2 ). Accordingly, in the second embodiment, the main body M is not interposed in the flange adjusting mechanism in the direction Y. 
     Hereinafter, an example of a specific forming aspect by the upper die  12 A and the lower die  11  according to the second embodiment will be described in detail. First, as illustrated in  FIG. 10A , the metal pipe material  14  is retained on the cavity surface  16  of the main cavity portion MC. Next, as illustrated in  FIG. 10B , the upper die  12 A is made to approach the lower die  11  side in the direction Z, and the flange adjusting members  191  and  192  are advanced into the sub-cavity portion SC along the direction Z to abut on the lower die  11 . According to this, the metal pipe material  14  is hermetically sealed by the lower die  11 , the upper die  12 , and the flange adjusting members  191  and  192  when seen from the direction X. 
     Next, as illustrated in  FIG. 10C , a gas is injected into the metal pipe material  14  to temporarily form the metal pipe  100  including the pipe portion  100   a  and the flange portion  100   b . After the temporary forming of the metal pipe  100 , as illustrated in  FIG. 11A , the flange adjusting members  191  and  192  are retreated from the sub-cavity portion SC into the holes  12   b  and  12   c , respectively. In addition, the upper die  12 A is further moved toward the lower die  11  side, and gas supply by the gas supply unit  60  is restarted. According to this, as illustrated in  FIG. 11B , main forming of the metal pipe  101 , which includes the pipe portion  101   a  and the flange portion  101   b , is performed from the temporarily formed metal pipe  100 . 
     According to the second embodiment, it is also possible to exhibit the same operational effect as in the first embodiment. In addition, the flange adjusting members  191  and  192  according to the second embodiment are provided in a manner capable of being accommodated in the upper die  12 A, and is advanced and retreated along the direction Z. In this case, in comparison to the first embodiment, it is not necessary to provide the flange adjusting members  91  and  92  which are moved at the inside of the sub-cavity portion SC along the direction Y, and the flange adjusting mechanisms  90  and  90  between which the main body M is interposed in the direction Y and which drive the flange adjusting members  91  and  92 . In other words, after temporary forming of the metal pipe  100 , the flange adjusting members  191  and  192  may not be provided on an outer side of the sub-cavity portion SC along the direction Y. According to this, in the second embodiment, injection of the metal pipe material  14  into the forming device  10 , and extraction of the metal pipe  101  including the pipe portion  101   a  and the flange portion  101   b  from the forming device  10  are not hindered by the flange adjusting members  91  and  92  and the flange adjusting mechanisms  90  and  90  differently from the first embodiment. 
     Next, description will be given of a forming device according to a third embodiment with reference to  FIGS. 12A to 12C , and  FIGS. 13A and 13B . As illustrated in  FIG. 12A , in the third embodiment, a lower die  11 A is provided with a hole  11   b  that extends along the direction Z, a concave portion  11   c  that communicates with an upper end of the hole  11   b , a hole  11   d  that extends along the direction Z, and a concave portion  11   e  that communicates with an upper end of the hole  11   d  differently from the first embodiment. 
     The central axis of the hole  11   b  along the direction Z and the central axis of the concave portion  11   c  along the direction Z overlap each other, and a width of the hole  11   b  along the direction Y is narrower than a width of the concave portion  11   c  along the direction Y. Similarly, the central axis of the hole  11   d  along the direction Z, and the central axis of the concave portion  11   e  along the direction Z overlap each other, and a width of the hole  11   d  along the direction Y is narrower than a width of the concave portion  11   e  along the direction Y. 
     The concave portions  11   c  and  11   e  are provided with the main cavity portion MC interposed therebetween in the direction Y, and extend along the direction X. The concave portion  11   c  and the main cavity portion MC are spaced apart from each other by a predetermined distance in the direction Y, and the concave portion  11   e  and the main cavity portion MC are spaced apart from each other by a predetermined distance in the direction Y. A flange adjusting member  291  is accommodated in the hole  11   b  and the concave portion  11   c , and a flange adjusting member  292  is accommodated in the hole  11   d  and the concave portion  11   e . In other words, the flange adjusting members  291  and  292  are provided in a manner capable of being accommodated in the lower die  11 A. 
     The flange adjusting members  291  and  292  are columnar members which are formed from a metal or an alloy which move along the direction Z in a manner capable of being advanced and retreated in the sub-cavity portion SC, and examples thereof include a piston. A lower end of the flange adjusting member  291  and a lower end of the flange adjusting member  292  are attached to a flange adjusting mechanism (not illustrated). The flange adjusting members  291  and  292  are moved to be advanced into the sub-cavity portion SC, and are moved to be retreated from the sub-cavity portion SC by the flange adjusting mechanism. The flange adjusting mechanism according to the third embodiment is provided in the main body M of the forming device  10  in the same manner as in the second embodiment (refer to  FIG. 1 ). 
     The flange adjusting member  291  includes a base  291   a , and a tip end  291   b  on a further upper die  12  side in comparison to the base  291   a . The base  291   a  and the tip end  291   b  are approximately rectangular parallelepiped plate-shaped members which extend along the direction X. A length of the base  291   a  and the tip end  291   b  along the direction X is shorter than the length of the metal pipe material  14 , and is equal to or less than the length of the lower die  11 A along the direction X. A width of the tip end  291   b  along the direction Y is greater than a width of the base  291   a  along the direction Y. In addition, the width of the base  291   a  is less than a width of the hole  11   b , and the width of the tip end  291   b  is approximately the same as a width of the concave portion  11   c . The tip end  291   b  is accommodated in the concave portion  11   c  without a gap when the flange adjusting member  291  is retreated to the lower die  11 A side. Furthermore, a cavity may be formed at a part of the base  291   a . In addition, the base  291   a  may be constituted by a plurality of columnar members. 
     The flange adjusting member  292  includes a base  292   a  and a tip end  292   b  on a further upper die  12  side in comparison to the base  292   a . The base  292   a  and the tip end  292   b  are approximately rectangular parallelepiped plate-shaped members which extend along the direction X. For example, a length of the base  292   a  and the tip end  292   b  along the direction X is approximately the same as the length of the metal pipe material  14 . A width of the tip end  292   b  along the direction Y is greater than a width of the base  292   a  along the direction Y. In addition, the width of the base  292   a  is less than a width of the hole  11   d , and the width of the tip end  292   b  is approximately the same as a width of the concave portion  11   e . The tip end  292   b  is accommodated in the concave portion  11   e  without a gap when the flange adjusting member  292  is retreated to the lower die  11 A side. Furthermore, a cavity may be formed at a part of the base  292   a . In addition, the base  292   a  may be constituted by a plurality of columnar members. 
     Hereinafter, an example of a specific forming aspect by the upper die  12  and the lower die  11 A according to the third embodiment will be described in detail. First, as illustrated in  FIG. 12A , the metal pipe material  14  is retained on the cavity surface  16  of the main cavity portion MC. In addition, the flange adjusting members  291  and  292  are advanced into the sub-cavity portion SC along the direction Z. At this time, only the tip ends  291   b  and  292   b  are advanced into the sub-cavity portion SC. 
     Next, as illustrated in  FIG. 12B , the upper die  12  is made to approach the lower die  11 A side in the direction Z in order for the upper die  12  to abut on the tip ends  291   b  and  292   b . According to this, the metal pipe material  14  is hermetically sealed by the lower die  11 , the upper die  12 , the tip end  291   b  of the flange adjusting member  291 , and the tip end  292   b  of the flange adjusting member  292  when seen from the direction X. 
     Next, as illustrated in  FIG. 12C , a gas is injected into the metal pipe material  14  to temporarily form the metal pipe  100  including the pipe portion  100   a  and the flange portion  100   b . After the temporary forming of the metal pipe  100 , as illustrated in  FIG. 13A , the flange adjusting members  291  and  292  are retreated from the sub-cavity portion SC into the holes  11   b  and  11   d , respectively. According to this, the tip end  291   b  is accommodated in the concave portion  11   c  and the tip end  292   b  is accommodated in the concave portion  11   e . In addition, the upper die  12  is further moved to the lower die  11 A side, and gas supply by the gas supply unit  60  is restarted. According to this, as illustrated in  FIG. 13B , main forming of the temporarily formed metal pipe  100  is performed, thereby forming the metal pipe  101  including the pipe portion  101   a  and the flange portion  101   b.    
     According to the third embodiment, it is also possible to exhibit the same operational effect as in the second embodiment. In addition, in the third embodiment, the width of the tip end  291   b  along the direction Y is greater than the width of the hole  11   b  along the direction Y, and the width of the tip end  292   b  along the direction Y is greater than the width of the hole  11   d  along the direction Y. According to this, when the flange adjusting members  291  and  292  are retreated into the lower die  11 A, the tip end  291   b  is hooked by the concave portion  11   c , and the tip end  292   b  is hooked by the concave portion  11   e . According to this, in a case where the flange adjusting member  291  is accommodated in the lower die  11 A, positioning of the flange adjusting member  291  is realized by the tip end  291   b  and the concave portion  11   c . Similarly, in a case where the flange adjusting member  292  is accommodated in the lower die  11 A, positioning of the flange adjusting member  292  is realized by the tip end  292   b  and the concave portion  11   e . According to this, when the shapes of the tip ends  291   b  and  292   b , and the concave portions  11   c  and  11   e  are determined, positioning of the flange adjusting members  291  and  292  when being retreated becomes easy. 
     Hereinbefore, preferred embodiments of the invention have been described, but the invention is not limited to the embodiments and the modification example. The forming device  10  according to the embodiments and the modification example may not include the heating mechanism  50 , and the metal pipe material  14  may be heated in advance. 
     In the drive mechanism  80  according to the embodiments and the modification example, only the upper die is moved, but the lower die may be moved in addition to the upper die or instead of the upper die. In a case where the lower die is moved, the lower die is not fixed to the base stage, and is attached to the slide of the drive mechanism. 
     In addition, the metal pipe  101  according to the embodiments and the modification example may include the flange portion  101   b  on only one side thereof. In this case, the number of the sub-cavity portion, which is formed by the upper die  12  and the lower die  11 , is one, and the number of the flange adjustment member is also one. 
     In addition, the flange portion  101   b  of the metal pipe  101  according to the embodiments and the modification example may be formed at a part of the metal pipe  101 . In this case, the surface of each of the flange adjusting members on the main cavity side may be recessed along the direction Y in correspondence with a site at which the flange portion is formed. In addition, a non-recessed portion on the surface may become a part of a surface that partitions the main cavity portion MC during temporary forming of the metal pipe material. When using the flange adjusting member as described above, it is possible to maintain hermetic sealing properties of the main cavity portion MC during temporary forming of the metal pipe material, and it is possible to form the flange portion only in a desired region. 
     In addition, in the first embodiment, the flange adjusting members  91  and  92  have approximately rectangular parallelepiped shape, but there is no limitation to the shape. The shape of the flange adjusting member is not limited, for example, as long as a surface of the flange adjusting member, which faces the main cavity portion MC, has a shape that hermetically seals the main cavity portion MC. For example, the flange adjusting member may have a triangular shape or a semi-circular shape in a plan view. 
     In addition, in the first embodiment, the upper die  12  and the flange adjusting members  91  and  92  are brought into contact with each other through movement of the upper die  12 , but there is no limitation thereto. For example, the upper die  12  may be made to approach the lower die  11  in such a manner that a slight gap is provided between the upper die  12  and the flange adjusting members  91  and  92 . 
     In addition, in the modification example of the first embodiment, the fixing members  113   a  and  113   b  may be integrated with each other, and the fixing members  114   a  and  114   b  may be integrated with each other. In this case, the fixing members  113   a  and  113   b , which are integrated with each other, are provided with an opening into which the flange adjusting member  91  and the rod  93  can be inserted. Similarly, the fixing members  114   a  and  114   b , which are integrated with each other, are provided with an opening into which the flange adjusting member  92  and the rod  94  can be inserted. In this modification example, it is not necessary for the fixing members  113   a ,  113   b ,  114   a , and  114   b  to be provided. 
     In addition, in the second embodiment, the flange adjusting members  191  and  192  may be provided on the lower die  11  side instead of being provided on the upper die  12 A side. In addition, in the second embodiment, the flange adjusting members  191  and  192  may be provided on both of the upper die  12 A side and the lower die  11  side. 
     In addition, in the third embodiment, the flange adjusting members  291  and  292  may be provided on the upper die  12  side instead of being provided on the lower die  11 A side. In addition, in the third embodiment, the flange adjusting members  291  and  292  may be provided on both of the upper die  12  side and the lower die  11 A side. 
     In addition, the metal pipe material  14  that is prepared between the upper die  12  and the lower die  11  may have an elliptical cross-sectional shape in which a diameter in a right and left direction is longer than a diameter in an upper and lower direction. 
     It should be understood that the invention is not limited to the above-described embodiment, but may be modified into various forms on the basis of the spirit of the invention. Additionally, the modifications are included in the scope of the invention.