JP2018196894A - Energization heater and energization heating method - Google Patents

Abstract

To provide an energization heater capable of reducing unevenness of an axial distribution of temperatures of a metal pipe material on heating, and an energization method.SOLUTION: Electrodes 101, 102 energize a part in the circumferential direction of the outer peripheral face 14a of a metal pipe material 14 and does not energize another part in the circumferential direction of the outer peripheral face 14a of the metal pipe material 14. Accordingly, the metal pipe material 14 is arranged on the electrodes 101, 102 so that a part (first region E1) on a bend projection in the circumferential direction of the outer peripheral face 14a of the metal pipe material 14 may be energized. In the case of such an arrangement, energization is performed at the bend projection side (first region E1) of the metal pipe material 14 hard to heat because of a long current path, but energization is not performed at the recess side (first region E2) of the metal pipe material hard to heat because of a short current path.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an energization heating device and an energization heating method for energizing and heating a metal pipe material.

  2. Description of the Related Art Conventionally, a molding apparatus is known that performs blow molding by closing a metal pipe with a molding die. For example, the molding apparatus disclosed in Patent Document 1 includes a molding die and a gas supply unit that supplies gas into the metal pipe material. In this molding apparatus, the heated metal pipe material is placed in a molding die, and the metal pipe material is expanded by supplying gas from the gas supply unit to the metal pipe material with the molding die closed. Is formed into a shape corresponding to the shape of the molding die.

JP2015-112608A

  In a conventional forming apparatus, a metal pipe material is held by an electrode before expansion molding, and the metal pipe material is heated by energizing through the electrode. Here, since the metal pipe as a finished product has been required to have various shapes, the metal pipe material having various shapes has been used accordingly. Here, as a metal pipe material, a bent material as a whole may be used. However, since the current tends to flow through the metal pipe material through the shortest path, there is a problem that when the bent metal pipe material is energized and heated, the metal pipe material is likely to have temperature unevenness in the axial direction of the metal pipe material. is there. Therefore, it is required to suppress uneven temperature distribution in the axial direction of the metal pipe material.

  Then, an object of this invention is to provide the electrical heating apparatus and the electrical heating method which can reduce the nonuniformity of the axial temperature distribution of the metal pipe material at the time of a heating.

  An electric heating apparatus according to the present invention is an electric heating apparatus that supplies electric power to a metal pipe material and includes an electrode that supplies electric power in contact with an outer peripheral surface of the metal pipe material, and the electrode is an outer periphery of the metal pipe material. Energization is performed on a part in the circumferential direction of the surface, and energization is not performed on other parts in the circumferential direction of the outer peripheral surface of the metal pipe material.

  According to the energization heating apparatus according to the present invention, the electrode energizes a part of the outer peripheral surface of the metal pipe material in the circumferential direction and energizes the other part of the outer peripheral surface of the metal pipe material in the circumferential direction. Do not do. Therefore, the metal pipe material can be disposed with respect to the electrode so that a part of the outer peripheral surface of the metal pipe material on the protruding side of the bending in the circumferential direction is energized. When arranged in this way, energization is performed on the protruding side of the bending of the metal pipe material where the current path is long and difficult to be heated, and the bending depression of the metal pipe material where the current path is short and easy to heat There is no energization on the side. Thereby, it can suppress that the emitted-heat amount becomes large by the said position by suppressing that an electric current concentrates and flows into the hollow side of bending of a metal pipe material. As described above, the uneven temperature distribution in the axial direction of the metal pipe material during heating can be reduced.

  In the electric heating apparatus, the electrode includes a first portion and a second portion that are spaced apart from each other and sandwich the outer peripheral surface of the metal pipe material, and the first portion is a circumferential direction of the outer peripheral surface of the metal pipe material The second portion does not energize other portions in the circumferential direction of the outer peripheral surface of the metal pipe material. Thereby, among the metal pipe materials, the portion to be energized may be supported by the first portion, and the portion not to be energized may be supported by the second portion, so that the metal pipe material can be easily aligned with the electrode. .

  In the electric heating device, the electrode is in contact with a portion of the outer peripheral surface of the metal pipe material in the circumferential direction to support the metal pipe material, and in contact with another portion of the outer peripheral surface of the metal pipe material in the circumferential direction. And an insulating part for supporting the metal pipe material. As described above, by providing the conductive portion and the insulating portion, it is possible to easily configure the portion that conducts electricity and the portion that does not conduct electricity.

  An electric heating method according to the present invention is an electric heating method for supplying electric power to a metal pipe material by using the electric heating device described above, and a step of preparing a metal pipe material bent so as to protrude in the bending direction; A step of arranging the metal pipe material with respect to the electrode such that a portion of the outer peripheral surface of the metal pipe material on the protruding side of the bending in the circumferential direction is energized; and a step of energizing and heating the metal pipe material with the electrode; .

  According to the electric heating method according to the present invention, the same actions and effects as those of the electric heating apparatus described above can be obtained.

  According to the electric heating apparatus of the present invention, it is possible to provide an electric heating apparatus and an electric heating method that can reduce the uneven temperature distribution in the axial direction of the metal pipe material during heating.

It is a schematic block diagram which shows the shaping | molding apparatus in which the metal pipe material heated with the electrical heating apparatus which concerns on this embodiment is used. It is an enlarged view of the periphery of the electrode, (a) is a diagram showing a state in which the electrode holds the metal pipe material, (b) is a diagram showing a state in which the seal member is pressed against the electrode, (c) is a front view of the electrode It is. It is a perspective view of the energization heating device concerning this embodiment. It is a schematic diagram of the electric heating apparatus which concerns on this embodiment. It is sectional drawing along the VV line shown in FIG. It is sectional drawing of the electrode which concerns on a modification. It is sectional drawing of the electrode which concerns on a modification. It is sectional drawing of the electrode which concerns on a modification.

  Hereinafter, a preferred embodiment of a forming apparatus in which a metal pipe material heated by an electric heating apparatus according to the present invention is used will be described with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same part or an equivalent part, and the overlapping description is abbreviate | omitted.

<Configuration of molding equipment>
FIG. 1 is a schematic configuration diagram of a molding apparatus according to the present embodiment. As shown in FIG. 1, a molding apparatus 10 for molding a metal pipe includes a molding die 13 including an upper die 12 and a lower die 11, and a drive mechanism 80 that moves at least one of the upper die 12 and the lower die 11. The pipe holding mechanism 30 that holds the metal pipe material 14 disposed between the upper mold 12 and the lower mold 11, and the metal pipe material 14 that is held and heated between the upper mold 12 and the lower mold 11 are pressurized. A gas supply unit 60 for supplying gas (gas), and a pair of gas supply mechanisms 40, 40 for supplying gas from the gas supply unit 60 into the metal pipe material 14 held by the pipe holding mechanism 30. And a water circulation mechanism 72 that forcibly cools the molding die 13, and controls the driving mechanism 80, the pipe holding mechanism 30, and the gas supply unit 60. It is configured to include a and.

  The lower mold 11 which is one of the molding dies 13 is fixed to the base 15. The lower mold 11 is composed of a large steel block, and includes, for example, a rectangular cavity (concave portion) 16 on the upper surface thereof. A cooling water passage 19 is formed in the lower mold 11 and is provided with a thermocouple 21 inserted from below at a substantially central position. The thermocouple 21 is supported by a spring 22 so as to be movable up and down.

  Further, a space 11a is provided in the vicinity of the left and right ends (left and right ends in FIG. 1) of the lower mold 11, and a lower holding member 17 described later, which is a movable portion of the pipe holding mechanism 30, is provided in the space 11a. , 18 etc. are arranged to be movable up and down. The metal pipe material 14 is placed on the lower holding members 17 and 18 so that the lower holding members 17 and 18 are arranged between the upper mold 12 and the lower mold 11. Contact material 14.

  The lower holding members 17 and 18 are fixed to an advancing / retreating rod 95 that is a movable portion of an actuator (not shown) constituting the pipe holding mechanism 30. This actuator is for vertically moving the lower holding members 17, 18 and the like, and the fixed portion of the actuator is held on the base 15 side together with the lower mold 11.

  The upper mold 12, which is the other of the molding dies 13, is fixed to a later-described slide 81 that constitutes the drive mechanism 80. The upper mold 12 is composed of a large steel block, and has a cooling water passage 25 formed therein, and is provided with, for example, a rectangular cavity (recess) 24 on the lower surface thereof. The cavity 24 is provided at a position facing the cavity 16 of the lower mold 11.

  A space 12a is provided in the vicinity of the left and right ends (left and right ends in FIG. 1) of the upper mold 12 in the same manner as the lower mold 11, and a movable portion of the pipe holding mechanism 30 will be described later in the space 12a. The upper holding members 17, 18 and the like are arranged so as to be movable up and down. Then, in a state where the metal pipe material 14 is placed on the upper holding members 17 and 18, the upper holding members 17 and 18 move between the upper mold 12 and the lower mold 11 by moving downward. Contact the placed metal pipe material 14.

  The upper holding members 17 and 18 are fixed to an advance / retreat rod 96 which is a movable part of an actuator constituting the pipe holding mechanism 30. This actuator is for moving the upper holding members 17, 18 and the like up and down, and the fixed part of the actuator is held on the slide 81 side of the drive mechanism 80 together with the upper mold 12.

  In the right side portion of the pipe holding mechanism 30, a semicircular arc-shaped groove 18 a corresponding to the outer peripheral surface of the metal pipe material 14 is formed on each of the surfaces where the holding members 18 and 18 face each other (see FIG. 2). ), And can be placed so that the metal pipe material 14 fits into the concave groove 18a. In addition, a tapered concave surface 18b is formed on the front surface of the holding member 18 (the surface in the outer direction of the mold). Therefore, when the metal pipe material 14 is sandwiched from above and below by the right side portion of the pipe holding mechanism 30, the outer periphery of the right end portion of the metal pipe material 14 can be surrounded so as to be in close contact over the entire circumference. ing.

  In the left portion of the pipe holding mechanism 30, a semicircular arc-shaped groove 17a corresponding to the outer peripheral surface of the metal pipe material 14 is formed on each of the surfaces where the holding members 17, 17 face each other (see FIG. 2). ), And can be placed so that the metal pipe material 14 fits into the concave groove 17a. In addition, a tapered concave surface 17b is formed on the front surface of the holding member 17 (the surface in the outer direction of the mold). Therefore, when the metal pipe material 14 is sandwiched from above and below by the left portion of the pipe holding mechanism 30, the outer periphery of the left end portion of the metal pipe material 14 can be surrounded so as to be in close contact over the entire circumference. ing.

  As shown in FIG. 1, the drive mechanism 80 includes a slide 81 that moves the upper mold 12 so that the upper mold 12 and the lower mold 11 are aligned with each other, and a shaft 82 that generates a driving force for moving the slide 81. And a connecting rod 83 for transmitting the driving force generated by the shaft 82 to the slide 81. The shaft 82 extends in the left-right direction above the slide 81 and is rotatably supported. An eccentric crank 82a that protrudes from the left and right ends and extends in the left-right direction at a position away from the axis. Have. The eccentric crank 82 a and a rotating shaft 81 a provided in the upper part of the slide 81 and extending in the left-right direction are connected by a connecting rod 83. In the drive mechanism 80, the height of the eccentric crank 82a is changed by controlling the rotation of the shaft 82 by the control unit 70, and the change in the position of the eccentric crank 82a is transmitted to the slide 81 via the connecting rod 83. Thus, the vertical movement of the slide 81 can be controlled. Here, the swinging (rotating motion) of the connecting rod 83 that occurs when the position change of the eccentric crank 82a is transmitted to the slide 81 is absorbed by the rotating shaft 81a. The shaft 82 rotates or stops according to the driving of a motor or the like controlled by the control unit 70, for example.

  Returning to FIG. 1, each of the pair of gas supply mechanisms 40 is connected to a cylinder unit 42, a cylinder rod 43 that moves forward and backward in accordance with the operation of the cylinder unit 42, and a tip of the cylinder rod 43 on the pipe holding mechanism 30 side. And a sealing member 44. The cylinder unit 42 is mounted and fixed on the block 41. A tapered surface 45 is formed at the tip of the seal member 44 so as to be tapered, and is configured to fit the tapered concave surfaces 17b, 18b of the holding members 17, 18 (see FIG. 2). The seal member 44 extends from the cylinder unit 42 toward the tip, and as shown in detail in FIGS. 2A and 2B, a gas passage through which the high-pressure gas supplied from the gas supply unit 60 flows. 46 is provided.

  The gas supply unit 60 includes a gas source 61, an accumulator 62 that stores the 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 valve 64 and a switching valve 65 provided in one tube 63; a second tube 67 extending from the accumulator 62 to a gas passage 46 formed in the seal member 44; The pressure control valve 68 and the check valve 69 are provided. The pressure control valve 64 serves to supply the cylinder unit 42 with a gas having an operating pressure adapted to the pressing force of the seal member 44 against the metal pipe material 14. The check valve 69 serves to prevent the high pressure gas from flowing back in the second tube 67. The pressure control valve 68 provided in the second tube 67 serves to supply a gas having an operating pressure for expanding the metal pipe material 14 to the gas passage 46 of the seal member 44 under the control of the control unit 70. Fulfill.

  The control unit 70 can supply a gas having a desired operating pressure into the metal pipe material 14 by controlling the pressure control valve 68 of the gas supply unit 60. Moreover, the control part 70 acquires temperature information from the thermocouple 21, and controls the drive mechanism 80 grade | etc., By information being transmitted from (A) shown in FIG.

  The water circulation mechanism 72 includes a water tank 73 that stores water, a water pump 74 that pumps up and pressurizes the water stored in the water tank 73 and sends the water to the cooling water passage 19 of the lower mold 11 and the cooling water passage 25 of the upper mold 12. It consists of a pipe 75. Although omitted, a cooling tower for lowering the water temperature and a filter for purifying water may be interposed in the pipe 75.

<Metal pipe forming method using forming equipment>
Next, a method for forming a metal pipe using the forming apparatus 10 will be described. First, a cylindrical metal pipe material 14 of a hardenable steel type is prepared. The metal pipe material 14 is placed (introduced) on the holding members 17 and 18 provided on the lower mold 11 side using a robot arm or the like which will be described later. The metal pipe material 14 at the time of charging is in a state of being heated by an energization heating device 100 described later. Since the concave grooves 17a and 18a are formed in the holding members 17 and 18, the metal pipe material 14 is positioned by the concave grooves 17a and 18a.

  Next, the control unit 70 controls the drive mechanism 80 and the pipe holding mechanism 30 to cause the pipe holding mechanism 30 to hold the metal pipe material 14. Specifically, the upper mold 12 and the holding members 17 and 18 held on the slide 81 side by the drive mechanism 80 are moved to the lower mold 11 side, and the holding members 17 and 17 included in the pipe holding mechanism 30 are moved. By actuating an actuator that enables the 18 and the like and the holding members 17 and 18 to advance and retreat, the vicinity of both ends of the metal pipe material 14 is sandwiched by the pipe holding mechanism 30 from above and below. This clamping is performed in such a manner that the metal pipe material 14 is in close contact with the entire circumference near both ends due to the presence of the concave grooves 17 a and 18 a formed in the holding members 17 and 18.

  At this time, as shown in FIG. 2 (a), the end of the metal pipe material 14 on the holding member 18 side has a groove 18a and a tapered concave surface of the holding member 18 in the extending direction of the metal pipe material 14. It protrudes to the seal member 44 side from the boundary with 18b. Similarly, the end of the metal pipe material 14 on the holding member 17 side protrudes more toward the seal member 44 than the boundary between the concave groove 17a and the tapered concave surface 17b of the holding member 17 in the extending direction of the metal pipe material 14. Yes. The lower surfaces of the upper holding members 17 and 18 and the upper surfaces of the lower holding members 17 and 18 are in contact with each other. However, the configuration is not limited to the configuration in which the metal pipe material 14 is in close contact with the entire circumference of both ends, and the configuration may be such that the holding members 17 and 18 are in contact with part of the metal pipe material 14 in the circumferential direction.

  Subsequently, the molding die 13 is closed with respect to the heated metal pipe material 14 by the control of the drive mechanism 80 by the control unit 70. As a result, the cavity 16 of the lower mold 11 and the cavity 24 of the upper mold 12 are combined, and the metal pipe material 14 is disposed and sealed in the cavity portion between the lower mold 11 and the upper mold 12.

  Thereafter, the cylinder unit 42 of the gas supply mechanism 40 is operated to advance the seal member 44 to seal both ends of the metal pipe material 14. At this time, as shown in FIG. 2B, the seal member 44 is pressed against the end of the metal pipe material 14 on the holding member 18 side, whereby the boundary between the groove 18 a and the tapered concave surface 18 b of the holding member 18. The portion that protrudes further toward the seal member 44 is deformed in a funnel shape so as to follow the tapered concave surface 18b. Similarly, when the seal member 44 is pressed against the end portion of the metal pipe material 14 on the holding member 17 side, the portion protruding to the seal member 44 side from the boundary between the concave groove 17a and the tapered concave surface 17b of the holding member 17. However, it deforms in a funnel shape along the tapered concave surface 17b. After the sealing is completed, high-pressure gas is blown into the metal pipe material 14, and the metal pipe material 14 softened by heating is formed so as to follow the shape of the cavity portion.

  Since the metal pipe material 14 is heated to a high temperature (around 950 ° C.) and softened, the gas supplied into the metal pipe material 14 is thermally expanded. For this reason, for example, the supplied gas is compressed air, and the metal pipe material 14 at 950 ° C. can be easily expanded by the thermally expanded compressed air.

  The outer peripheral surface of the metal pipe material 14 swelled by blow molding is brought into contact with the cavity 16 of the lower mold 11 and rapidly cooled, and at the same time is brought into contact with the cavity 24 of the upper mold 12 to rapidly cool (the upper mold 12 and the lower mold 11 are Since the heat capacity is large and the temperature is controlled at a low temperature, if the metal pipe material 14 comes into contact, the heat of the pipe surface is taken away to the mold side at once, and quenching is performed. Such a cooling method is called mold contact cooling or mold cooling. Immediately after being quenched, austenite transforms to martensite (hereinafter, austenite transforms to martensite is referred to as martensite transformation). In the second half of the cooling, the cooling rate was reduced, so that martensite was transformed into another structure (truthite, sorbite, etc.) by recuperation. Therefore, it is not necessary to perform a separate tempering process. In the present embodiment, cooling may be performed by supplying a cooling medium into the cavity 24, for example, instead of or in addition to mold cooling. For example, the metal pipe material 14 is brought into contact with the mold (upper mold 12 and lower mold 11) until the temperature at which martensitic transformation begins, and then the mold is opened and the cooling medium (cooling gas) is used as the metal pipe material. The martensitic transformation may be generated by spraying on 14.

  As described above, blow molding is performed on the metal pipe material 14, and then cooling is performed to perform mold opening, thereby obtaining a metal pipe having a substantially rectangular cylindrical main body, for example.

  Next, with reference to FIG.3 and FIG.4, the electric heating apparatus 100 which concerns on this embodiment is demonstrated. The metal pipe material 14 used in the present embodiment has a bent shape so as to protrude in the bending direction D1 as a whole in the axial direction. Here, the metal pipe material 14 is curved in an arc shape so as to have a top at the center in the axial direction. In the following description, in the metal pipe material 14, the region on the side protruding in the bending direction D1 is referred to as a first region E1, and the region on the side opposite to the bending direction D1 is the second region E2. May be called. As shown in FIG. 4, when the metal pipe material 14 is viewed from the direction orthogonal to the bending direction D1 and the axial direction, the region on the outer peripheral side in the curved shape of the metal pipe material 14 is the first region E1, and the inner periphery The region on the side becomes the second region E2. It is assumed that the boundary between the first region E1 and the second region E2 is the center position in the width direction of the metal pipe material 14 when viewed from the direction shown in FIG. The energization heating device 100 has a function of holding such a metal pipe material 14 and energizing and heating. The energization heating device 100 has a function of setting the held metal pipe material 14 in the molding die 13. As shown in FIG. 4, the energization heating apparatus 100 includes a first electrode 101, a second electrode 102, a power supply unit 103, and a control unit 106. As shown in FIG. 3, the energization heating apparatus 100 includes a first position adjusting unit 108 provided for the first electrode 101 and a second position provided for the second electrode 102. And an adjustment unit 109.

  As shown in FIG. 4, the electrode 101 is a member that holds the metal pipe material 14 and energizes the metal pipe material 14 with the second electrode 102. The first electrode 101 includes a holding member (first portion) 101A and a holding member (second portion) 101B. The first electrode 101 is held by sandwiching the metal pipe material 14 between the holding member 101A and the holding member 101B. The first electrode 101 holds the vicinity of one end 14 b in the axial direction of the metal pipe material 14. One holding member 101 </ b> A is connected to a conducting wire 110 extending from the power supply unit 103. Thereby, the holding member 101 </ b> A can flow a current to the metal pipe material 14. Note that a detailed configuration of the first electrode 101 will be described later.

  The second electrode 102 is a member that holds the metal pipe material 14 at a position different from that of the first electrode 101 and energizes the metal pipe material 14 with the first electrode 101. The second electrode 102 includes a holding member 102A and a holding member 102B. The second electrode 102 is held by sandwiching the metal pipe material 14 between the holding member 102A and the holding member 102B. The second electrode 102 holds the vicinity of the other end portion 14 c in the axial direction of the metal pipe material 14. One holding member 102 </ b> A is connected to a conducting wire 111 extending from the power supply unit 103.

  The power supply unit 103 is a device that energizes the first electrode 101 and the second electrode 102 while the metal pipe material 14 is held by the first electrode 101 and the second electrode 102. The power supply unit 103 includes at least a DC power supply and a switch. The power supply unit 103 is electrically connected to the holding member 101 </ b> A of the first electrode 101 through the conducting wire 110, and is electrically connected to the holding member 102 </ b> A of the second electrode 102 through the conducting wire 111. The control unit 106 can perform control to switch on / off the switch of the power supply unit 103. Therefore, the control unit 106 can turn on the switch of the power supply unit 103 at a predetermined timing and allow the current to flow through the metal pipe material 14.

  As shown in FIG. 3, the first position adjustment unit 108 and the second position adjustment unit 109 are configured by robot arms. For example, the first position adjusting unit 108 horizontally moves the robot hand 108a that holds the metal pipe material 14, the movable unit 108b that can change the posture of the robot hand 108a three-dimensionally, and the movable unit 108b and the entire robot hand 108a. A pedestal 108c that rotates in the direction is provided. Thereby, the 1st position adjustment part 108 can hold | maintain the metal pipe material 14 from all angles and directions. In addition, the first position adjusting unit 108 can hold the metal pipe material 14 in any posture, and can place the held metal pipe material 14 in any position within the range of movement. The second position adjustment unit 109 has the same concept as the first position adjustment unit 108.

  The first position adjustment unit 108 is provided so as to be aligned with the first position adjustment unit 108 at a position separated from the second position adjustment unit 109. The first position adjustment unit 108 includes a first electrode 101 at the tip of the robot hand 108a. Thereby, the first position adjusting unit 108 can adjust the attachment position of the first electrode 101 with respect to the metal pipe material 14. The second position adjustment unit 109 includes a second electrode 102 at the tip of the robot hand 109a. As a result, the holding position by the first electrode with respect to the metal pipe material 14 can be adjusted.

  Each of the position adjusting units 108 and 109 can hold the metal pipe material 14 outside the molding die 13, convey the metal pipe material 14, and install it in the molding die 13. In addition, each position adjustment part 108 and 109 may be controlled by the control part 106 (refer FIG. 4). Therefore, the control unit 106 can hold the metal pipe material 14 in each of the position adjustment units 108 and 109 and perform energization heating, and then place the heated metal pipe material in the molding die 13.

  Next, a detailed configuration of the first electrode 101 will be described with reference to FIG. FIG. 5 is a cross-sectional view taken along line VV shown in FIG. Note that the second electrode 102 has the same concept as the first electrode 101, and thus description thereof is omitted.

  As shown in FIG. 5, the holding member 101A is a block-shaped member having a substantially rectangular cross section. Of the side surfaces of the holding member 101A, a groove portion 101Ab is formed on the facing surface 101Aa facing the holding member 101B. The groove portion 101Ab has a shape corresponding to the outer peripheral surface 14a of the metal pipe material 14, and has a shape recessed in a semicircular shape. When holding the metal pipe material 14, the holding member 101 </ b> A brings the groove 101 </ b> Ab into contact with the first region E <b> 1 on the outer peripheral surface 14 a of the metal pipe material 14. The holding member 101B is a block-shaped member having a substantially rectangular cross section. Of the side surfaces of the holding member 101B, a groove portion 101Bb is formed on the opposing surface 101Ba facing the holding member 101A. The groove portion 101Bb has a shape corresponding to the outer peripheral surface 14a of the metal pipe material 14, and has a shape recessed in a semicircular shape. When holding the metal pipe material 14, the holding member 101 </ b> B brings the groove 101 </ b> Ab into contact with the second region E <b> 2 on the outer peripheral surface 14 a of the metal pipe material 14. In addition, you may change suitably the shape of groove part 101Ab, 101Bb in the shape match | combined with the cross-sectional shape of the metal pipe material 14. FIG.

  Here, the first electrode 101 energizes a part of the outer circumferential surface 14a of the metal pipe material 14 in the circumferential direction and energizes other parts of the outer circumferential surface 14a of the metal pipe material 14 in the circumferential direction. Do not do. In the present embodiment, the first electrode 101 energizes the first region E1 in the circumferential direction of the outer peripheral surface 14a of the metal pipe material 14, and the first electrode 101 in the circumferential direction of the outer peripheral surface 14a of the metal pipe material 14 is. No energization is performed for the area E2. Of the first electrode 101, a portion that conducts electricity to a portion of the outer peripheral surface 14 a of the metal pipe material 14 in the circumferential direction is an energized portion 150 A, and other portions in the circumferential direction of the outer peripheral surface 14 a of the metal pipe material 14. A portion that is not energized to the portion may be described as a non-energized portion 150B. The non-energized portion 150 </ b> B is a portion that does not energize the metal pipe material 14 while being in contact with the outer peripheral surface 14 a of the metal pipe material 14 and supporting the metal pipe material 14.

  As described above, the first electrode 101 includes the holding member 101 </ b> A and the holding member 101 </ b> B that are spaced apart from each other and sandwich the outer peripheral surface 14 a of the metal pipe material 14. The holding member 101 </ b> A energizes the first region E <b> 1 in the circumferential direction of the outer peripheral surface 14 a of the metal pipe material 14. The holding member 101 </ b> B does not energize the second region E <b> 2 in the circumferential direction of the outer peripheral surface 14 a of the metal pipe material 14. Specifically, the holding member 101A is made of a conductive material. As the conductive material, for example, copper, aluminum, or the like is used. The holding member 101B is made of an insulating material. As the insulating material, for example, ceramics, mica, asbestos, glass fiber, or the like is used.

  With the above-described configuration, the holding member 101A functions as a conductive portion 121A that supports the metal pipe material 14 by contacting the first region E1 in the circumferential direction of the outer peripheral surface 14a of the metal pipe material 14. The holding member 101 </ b> A causes the current flowing from the conducting wire 110 to flow to the metal pipe material 14 through the groove 101 </ b> Ab. Alternatively, when the direction of the current is reversed, the holding member 101A causes the current flowing from the metal pipe material 14 to flow to the conducting wire 110 via the groove 101Ab. Therefore, the holding member 101 </ b> A functions as an energization portion 151 </ b> A for the metal pipe material 14. In the present specification, the “energization” means that a current flows from the electrode to the metal pipe material and a current from the metal pipe material is received. The holding member 101B functions as an insulating part 121B that supports the metal pipe material 14 by contacting the second region E2 in the circumferential direction of the outer peripheral surface 14a of the metal pipe material 14. Further, the holding member 101 </ b> B functions as a non-energized portion 151 </ b> B that does not energize the metal pipe material 14. In the example shown in FIG. 5, the entire holding member 101B is made of an insulating material. However, at least a portion in contact with the metal pipe material 14, that is, the groove 101Bb only needs to be made of an insulating material. For example, the entire surface of the holding member 101B made of a conductive material may be coated with an insulating material.

  Next, an energization heating method using the above-described energization heating apparatus 100 will be described.

  First, a step of preparing the metal pipe material 14 bent so as to protrude in the bending direction D1 as shown in FIG. 4 is executed. Next, the metal pipe material 14 is made to pass through the first electrode 101 and the second electrode so that a part of the outer circumferential surface 14a of the metal pipe material 14 on the protruding side in the circumferential direction (first region E1) is energized. The step of arranging the electrodes 102 is performed. In this step, the first region E1 of the outer peripheral surface 14a of the metal pipe material 14 is brought into contact with the groove portion 101Ab of the holding member 101A of the first electrode 101. In this step, the second region E2 of the outer peripheral surface 14a of the metal pipe material 14 is brought into contact with the groove portion 101Bb of the holding member 101B of the first electrode 101. In such a manner, the first electrode 101 holds the metal pipe material 14 by the holding members 101A and 101B. The second electrode 102 also holds the metal pipe material 14 in the same manner as the first electrode 101. Next, a step of energizing and heating the metal pipe material 14 with the first electrode 101 and the second electrode 102 is performed. In this step, the metal pipe material 14 is energized only by the holding member 101A among the first electrodes 101, and the energization is not performed by the holding member 101B. In the second electrode 102, the metal pipe material 14 is energized only by the holding member 102A, and the energization is not performed by the holding member 102B.

  Next, operations and effects of the electric heating device 100 and the electric heating method according to the present embodiment will be described.

  According to the energization heating apparatus 100 according to the present embodiment, the electrodes 101 and 102 energize a part of the outer peripheral surface 14 a of the metal pipe material 14 in the circumferential direction, and the periphery of the outer peripheral surface 14 a of the metal pipe material 14. Do not energize other parts in the direction. Therefore, the metal pipe material 14 is arranged with respect to the electrodes 101 and 102 so that a part of the outer peripheral surface 14a of the metal pipe material 14 on the protruding side of the bending in the circumferential direction (first region E1) is energized. be able to. When arranged in this way, energization is performed on the protruding side (first region E1) of the bending of the metal pipe material 14, which is a portion where the current path is long and difficult to be heated, and the current path becomes short and easily heated. No energization is performed on the bent hollow side (second region E2) of a certain metal pipe material. Thereby, it can suppress that the emitted-heat amount becomes large in the said position by suppressing that an electric current concentrates and flows into the hollow side of bending of the metal pipe material 14. FIG. As described above, the uneven temperature distribution in the axial direction of the metal pipe material 14 during heating can be reduced.

  In the electric heating apparatus 100, the electrodes 101 and 102 include holding members 101 </ b> A and 102 </ b> A and holding members 101 </ b> A and 101 </ b> B that are spaced apart from each other and sandwich the outer peripheral surface 14 a of the metal pipe material 14. The holding members 101A and 102A energize a part (first region E1) in the circumferential direction of the outer circumferential surface 14a of the metal pipe material 14, and the holding members 101B and 102B are circumferential directions of the outer circumferential surface 14a of the metal pipe material 14. The other portion (second region E2) is not energized. As a result, the metal pipe material 14 may be supported by the holding members 101A and 102A and the non-energized portions of the metal pipe material 14 may be supported by the holding members 101B and 102B. It is easy to align 14 positions.

  In the electric heating apparatus 100, the electrodes 101 and 102 are in contact with a part (first region E1) in the circumferential direction of the outer peripheral surface 14a of the metal pipe material 14 to support the metal pipe material 14, and a metal pipe 121A. And an insulating portion 121B that supports the metal pipe material 14 in contact with another portion (second region E2) in the circumferential direction of the outer peripheral surface 14a of the material 14. Thus, by providing the conductive portion 121A and the insulating portion 121B, the energized portion 151A that conducts electricity and the non-energized portion 151B that does not energize (for example, switching the energized portion as shown in FIGS. 7 and 8 to be described later). Can be easily configured (compared to the configuration to be performed).

  The energization heating method according to the present embodiment is an energization heating method in which the metal pipe material 14 is energized and heated using the above-described energization heating apparatus 100, and the metal pipe material 14 bent so as to protrude in the bending direction D1. And the metal pipe material 14 is applied to the electrodes 101 and 102 so that a part of the outer peripheral surface 14a of the metal pipe material 14 on the protruding side of the bending in the circumferential direction (first region E1) is energized. And a step of energizing and heating the metal pipe material 14 with the electrodes 101 and 102.

  According to the electric heating method according to the present embodiment, the same operations and effects as those of the electric heating device 100 described above can be obtained.

  The present invention is not limited to the embodiment described above.

  For example, the electrode may have a conductive portion and an insulating portion in one holding member. The electrode 200 shown in FIG. 6 includes holding members 200A and 200B. In the following description, the direction in which the holding members 200A and 200B are opposed to each other is referred to as a facing direction D2, and the direction perpendicular to the facing direction D2 and the axial direction is referred to as a width direction D3. The holding members 200A and 200B include conductive portions 201A and 201B made of a conductive material on one side in the width direction D3, and insulating portions 202A and 202B made of an insulating material on the other side in the width direction D3. Yes. The conducting wire 110 is connected to the conductive portion 201A. In this case, the conductive portion 201A and the conductive portion 201B are electrically connected to each other via the opposing surfaces 201Aa and 201Ba. However, the conducting wire 110 may be connected to the conductive portion 201B, or may be connected to both the conductive portion 201A and the conductive portion 201B. With the above configuration, the conductive portions 201A and 201B function as an energized portion 251A that energizes the metal pipe material 14. The insulating portions 202A and 202B function as a non-energized portion 251B that does not energize the metal pipe material 14.

  Such an electrode 200 energizes a part in the circumferential direction of the outer peripheral surface 14a of the metal pipe material 14 at the conductive portions 201A and 201B, and the outer periphery of the metal pipe material 14 at the insulating portions 202A and 202B. Current is not supplied to other portions in the circumferential direction of the surface 14a. Therefore, the metal pipe material 14 can be disposed with respect to the electrode 200 so that a part of the outer circumferential surface 14a of the metal pipe material 14 on the protruding side in the circumferential direction (first region E1) is energized. it can. Here, the metal pipe material 14 is disposed so that the first region E1 and the second region E2 are opposed to each other in the width direction D3, the first region E1 is in contact with the conductive portions 201A and 201B, The region E2 contacts the insulating portions 202A and 202B. When arranged in this way, energization is performed on the protruding side (first region E1) of the bending of the metal pipe material 14, which is a portion where the current path is long and difficult to be heated, and the current path becomes short and easily heated. No energization is performed on the bent hollow side (second region E2) of a certain metal pipe material. Thereby, it can suppress that the emitted-heat amount becomes large in the said position by suppressing that an electric current concentrates and flows into the hollow side of bending of the metal pipe material 14. FIG. As described above, the uneven temperature distribution in the axial direction of the metal pipe material 14 during heating can be reduced.

  The electrode 200 is in contact with a portion (first region E1) in the circumferential direction of the outer peripheral surface 14a of the metal pipe material 14 to support the metal pipe material 14, and the outer periphery of the metal pipe material 14 Insulating portions 202A and 202B that support the metal pipe material 14 in contact with other portions (second region E2) in the circumferential direction of the surface 14a. Thus, by providing the conductive portions 201A and 201B and the insulating portions 202A and 202B, the energized portion 251A that conducts electricity and the non-energized portion 251B that does not energize (for example, as shown in FIGS. 7 and 8 to be described later) It can be easily configured (compared to a configuration in which parts are switched).

  Further, for example, the electrode may be configured to be able to switch between an energized part and a non-energized part in one holding member. The electrode 300 shown in FIG. 7 includes holding members 300A and 300B. The holding members 300A and 300B include conductive portions 301A and 301B made of a conductive material on one side in the width direction D3, conductive portions 302A and 302B made of a conductive material on the other side in the width direction D3, and a width direction D3. An insulating portion 303A made of an insulating material between the conductive portions 301A and 302A at the central position in FIG. 3, and an insulating portion 303B made of an insulating material between the conductive portions 301B and 302B at the central position in the width direction D3. Yes.

  The conducting wire 110 is branched into a branching part 110a and a branching part 110b. In addition, a switch 112 is provided in the branch unit 110a, and a switch 113 is provided in the branch unit 110b. The branch part 110a is connected to the conductive part 301A, and the branch part 110b is connected to the conductive part 302A. In this case, the conductive portion 301A and the conductive portion 301B are electrically connected to each other via the opposing surfaces 301Aa and 301Ba. The conductive portion 302A and the conductive portion 302B are electrically connected to each other via the opposing surfaces 302Aa and 302Ba.

  The electrode 300 having the above-described configuration can switch between the energized portion 351A and the non-energized portion 351B. For example, when the switch 112 is turned on and the switch 113 is turned off as shown in FIG. 7, the conductive portions 301A and 301B function as the energized portion 351A, and the conductive portions 302A and 302B and the insulating portions 303A and 303B are non-energized portions. It functions as 351B. When the switch 112 is turned off and the switch 113 is turned on, the conductive portions 302A and 302B function as the energized portion 351A, and the conductive portions 301A and 301B and the insulating portions 303A and 303B function as the non-energized portion 351B.

  In such an electrode 300, when the switch 112 is turned on and the switch 113 is turned off, the conductive portions 301A and 301B energize a part in the circumferential direction of the outer peripheral surface 14a of the metal pipe material 14, and The conductive portions 302A and 302B are not energized to other portions in the circumferential direction of the outer peripheral surface 14a of the metal pipe material 14. Therefore, the metal pipe material 14 can be arranged with respect to the electrode 300 so that a part of the outer circumferential surface 14a of the metal pipe material 14 on the protruding side of the bending in the circumferential direction (first region E1) is energized. it can. Here, the metal pipe material 14 is disposed so that the first region E1 and the second region E2 face each other in the width direction D3, the first region E1 contacts the conductive portions 301A and 301B, The region E2 is in contact with the conductive portions 302A and 302B. When arranged in this way, energization is performed on the protruding side (first region E1) of the bending of the metal pipe material 14, which is a portion where the current path is long and difficult to be heated, and the current path becomes short and easily heated. No energization is performed on the bent hollow side (second region E2) of a certain metal pipe material. Thereby, it can suppress that the emitted-heat amount becomes large in the said position by suppressing that an electric current concentrates and flows into the hollow side of bending of the metal pipe material 14. FIG. As described above, the uneven temperature distribution in the axial direction of the metal pipe material 14 during heating can be reduced.

  Further, by switching the switches 112 and 113, the positions of the energized portion 351A and the non-energized portion 351B can be switched. That is, when the switch 112 is switched OFF and the switch 113 is switched ON from the state shown in FIG. 7, the conductive portions 302A and 302B become the energized portions 351A. In this case, the metal pipe material 14 is arranged with respect to the electrode 300 so that the first region E1 is in contact with the conductive portions 302A and 302B and the second region E2 is in contact with the conductive portions 301A and 301B. By providing such a switching mechanism, the energized portion 351A and the non-energized portion 351B can be set after the metal pipe material 14 is held by the electrode 300.

  Further, as shown in FIG. 8, an electrode 400 having more switching patterns may be employed. An electrode 400 shown in FIG. 8 includes holding members 400A and 400B. The electrode 400 shown in FIG. 8 includes conductive portions 401A, 401B, 402A, 402B, and insulating portions 403A having the same meaning as the conductive portions 301A, 301B, 302A, 302B and insulating portions 303A, 303B of the electrode 300 in FIG. 403B. Furthermore, the electrode 400 includes an insulating portion 404A provided on the opposing surface of the conductive portion 401A, an insulating portion 404B provided on the opposing surface of the conductive portion 401B, and an insulating portion 406A provided on the opposing surface of the conductive portion 402A. And an insulating portion 406B provided on the opposing surface of the conductive portion 402B. With such a configuration, when the metal pipe material 14 is held, the conductive portions 401A, 401B, 402A, and 402B are insulated from each other.

  The conducting wire 110 has a branching part 110a having a switch 112, a branching part 110b having a switch 113, a branching part 110c having a switch 114, and a branching part 110d having a switch 115. The branch portion 110a is connected to the conductive portion 401A, the branch portion 110b is connected to the conductive portion 402A, the branch portion 110c is connected to the conductive portion 401B, and the branch portion 110d is connected to the conductive portion 402B.

  The electrode 400 having the above-described configuration can switch between the energized portion 451A and the non-energized portion 451B. For example, as shown in FIG. 8, when the switches 112 and 113 are turned on and the switches 114 and 115 are turned off, the conductive portions 401A and 402A function as the energized portion 351A, and the conductive portions 401B and 402B and the insulating portions 403A and 403B. , 404A, 404B, 406A, 406B function as the non-energized portion 351B. Further, when the switches 114 and 115 are turned on and the switches 112 and 113 are turned off, the conductive portions 401B and 402B function as the energizing portion 351A, and the conductive portions 401A and 402A and the insulating portions 403A, 403B, 404A, 404B, and 406A. , 406B function as a non-energized portion 351B. Further, when the switches 112 and 114 are turned on and the switches 113 and 115 are turned off, the conductive portions 401A and 401B function as the energizing portion 351A, and the conductive portions 402A and 402B and the insulating portions 403A, 403B, 404A, 404B, and 406A. , 406B function as a non-energized portion 351B. Further, when the switches 113 and 115 are turned on and the switches 112 and 114 are turned off, the conductive portions 402A and 402B function as the energizing portion 351A, and the conductive portions 401A and 401B and the insulating portions 403A, 403B, 404A, 404B, and 406A. , 406B function as a non-energized portion 351B.

  In such an electrode 400, when the switches 112 and 113 are turned on and the switches 114 and 115 are turned off, the conductive portions 401A and 402A energize a part of the outer circumferential surface 14a of the metal pipe material 14 in the circumferential direction. In addition, the conductive portions 401B and 402B are not energized to other portions in the circumferential direction of the outer peripheral surface 14a of the metal pipe material 14. Therefore, the metal pipe material 14 can be arranged with respect to the electrode 300 so that a part of the outer circumferential surface 14a of the metal pipe material 14 on the protruding side of the bending in the circumferential direction (first region E1) is energized. it can. Here, the metal pipe material 14 is disposed so that the first region E1 and the second region E2 face each other in the facing direction D2, the first region E1 contacts the conductive portions 401A and 402A, and the second region E2 The region E2 is in contact with the conductive portions 401B and 402B. When arranged in this way, energization is performed on the protruding side (first region E1) of the bending of the metal pipe material 14, which is a portion where the current path is long and difficult to be heated, and the current path becomes short and easily heated. No energization is performed on the bent hollow side (second region E2) of a certain metal pipe material. Thereby, it can suppress that the emitted-heat amount becomes large in the said position by suppressing that an electric current concentrates and flows into the hollow side of bending of the metal pipe material 14. FIG. As described above, the uneven temperature distribution in the axial direction of the metal pipe material 14 during heating can be reduced.

  Further, by switching ON / OFF of the switches 112, 113, 114, and 115, the positions of the energized portion 451A and the non-energized portion 451B of the electrode 400 can be switched. Therefore, according to the arrangement of the metal pipe material 14, the energized portion 451A and the non-energized portion 451B are arranged such that the first region E1 is in contact with the energized portion 451A and the second region E2 is in contact with the non-energized portion 451B. The position can be switched.

  The shape of the metal pipe material is not limited to the above. For example, the metal pipe material may be bent rather than curved.

  Although the above-mentioned electric heating apparatus was the structure which has an electrode and a position adjustment part, it does not need to have a position adjustment part. That is, you may provide the electrode which has the structure of the same meaning as the above on the shaping | molding apparatus side. In this case, when the metal pipe material is installed in the forming apparatus, the electrode and the metal pipe material are aligned.

  DESCRIPTION OF SYMBOLS 100 ... Current heating apparatus, 101, 102, 200, 300, 400 ... Electrode, 103 ... Electric power supply part, 101A, 102A, 200A, 300A, 400A ... Holding member (1st part), 101B, 102B, 200B, 300B , 400B ... Holding member (second part) 121A, 201A, 201B, 301A, 301B, 302A, 302B, 401A, 401B, 402A, 402B ... Conductive part, 121B, 202A, 202B, 303A, 303B, 403A, 403B, 404A, 404B, 406A, 406B: Insulating part.

Claims (4)

An electric heating device for energizing and heating a metal pipe material,
An electrode for supplying power in contact with the outer peripheral surface of the metal pipe material;
The electrode is
An energization heating apparatus that energizes a portion of the metal pipe material in the circumferential direction of the outer peripheral surface and does not energize other portions of the metal pipe material in the circumferential direction of the outer peripheral surface. The electrode includes a first portion and a second portion that are spaced apart from each other and sandwich the outer peripheral surface of the metal pipe material.
The first portion energizes the portion of the metal pipe material in the circumferential direction of the outer peripheral surface,
2. The energization heating apparatus according to claim 1, wherein the second portion does not energize the other portion in the circumferential direction of the outer peripheral surface of the metal pipe material. The electrode is
A conductive portion that supports the metal pipe material in contact with the portion of the metal pipe material in the circumferential direction of the outer peripheral surface;
The electric heating apparatus according to claim 1, further comprising: an insulating portion that contacts the other portion in the circumferential direction of the outer peripheral surface of the metal pipe material and supports the metal pipe material. An energization heating method of energizing and heating the metal pipe material using the energization heating device according to any one of claims 1 to 3,
Preparing the metal pipe material bent so as to protrude in a bending direction;
Disposing the metal pipe material with respect to the electrode so that a portion of the outer circumferential surface of the metal pipe material on the protruding side of the bending in the circumferential direction is energized;
Energizing and heating the metal pipe material with the electrode.

Images