JP2022078380A - Electric conduction heating device - Google Patents

Abstract

To provide an electric conduction heating device that is able to improve the performance of electric conduction heating.SOLUTION: In an electric heating device 50, an electrode 18 includes, in addition to an electrode body unit 110, a displacement allowance portion 120 that allows displacement of a contact surface 18a that is in contact with an outer peripheral surface 14a of a metal pipe material 14. This displacement allowance portion 120 has a conductive member 121 that is easily deformed in a radial direction of the contact surface 18a, compared with the electrode body portion 110. For example, when an outer diameter of the metal pipe material 14 is large due to the influence of dimensional tolerance or the like, the conductive member 121 deforms in a radial direction of the contact surface 18a. Accordingly, the displacement allowance portion 120 allows displacement of the contact surface 18a and can absorb dimensional tolerance of the metal pipe material 14. Thus, satisfactory contact between the contact surface 18a and the metal pipe material 14 can be maintained.SELECTED DRAWING: Figure 3

Description

The present invention relates to an energizing heating device.

Conventionally, a molding apparatus is known in which a metal pipe is closed by a molding die and blow molded. For example, the molding apparatus disclosed in Patent Document 1 includes a molding die and a gas supply unit for supplying gas into a metal pipe material. In this molding apparatus, a heated metal pipe material is placed in a molding die, and the metal pipe material is expanded by supplying gas from a gas supply unit to the metal pipe material in a state where the molding die is closed. Is molded into a shape corresponding to the shape of the molding die.

Japanese Patent Application Laid-Open No. 2015-112608

In the conventional molding apparatus, both ends of the metal pipe material are held by electrodes, and electricity is applied from each electrode to heat the metal pipe material. Here, the contact surface of the electrode is set to a size corresponding to the outer peripheral surface of the metal pipe material. however. Due to the inclusion of dimensional tolerances in the metal pipe material, the contact state between the outer diameter of the metal pipe material and the contact surface of the electrode may vary. In such a case, the contact state between the contact surface of the electrode and the metal pipe material is affected, and the heating ultimate temperature varies, which affects the performance of energization heating.

Therefore, an object of the present invention is to provide an energization heating device capable of improving the performance of energization heating.

The energization heating device according to the present invention is an energization heating device in which an electrode is brought into contact with a metal pipe material to energize and heat the metal pipe. A displacement allowable portion that allows displacement of the contact surface that comes into contact with the surface is provided, and the displacement allowable portion has a conductive member that is more easily deformed in the radial direction of the contact surface as compared with the electrode main body portion.

In this energization heating device, the electrode includes, in addition to the electrode main body portion, a displacement allowable portion that allows displacement of the contact surface that comes into contact with the outer peripheral surface of the metal pipe material. This displacement allowable portion has a conductive member that is more easily deformed in the radial direction of the contact surface than the electrode main body portion. For example, when the outer diameter of the metal pipe material is large due to the influence of dimensional tolerance or the like, the conductive member is deformed in the radial direction of the contact surface. Thereby, the displacement allowable portion can allow the displacement of the contact surface and absorb the dimensional tolerance of the metal pipe material. Therefore, a good contact state between the contact surface and the metal pipe material can be maintained. As a result, the performance of energization heating can be improved.

The conductive member includes a base portion extending in a band shape along the circumferential direction of the contact surface, and a plurality of elastic portions connected to the base portion and formed so as to line up in the circumferential direction, and the elastic portions are pressed in the radial direction. Therefore, an elastic force may be generated in the radial direction. When the contact surface comes into contact with a metal pipe material having a large outer diameter, the elastic portion of the conductive member is pressed in the radial direction. At this time, in the conductive member, the metal pipe material can press the contact surface against the metal pipe material by generating an elastic force while absorbing the dimensional tolerance of the metal pipe material. This makes it possible to maintain a good contact state between the contact surface and the metal pipe material.

The electrode main body portion may have an outer peripheral portion arranged on the outer peripheral side of the displacement allowable portion and an inner peripheral portion arranged on the inner peripheral side of the displacement allowable portion to form a contact surface. In this case, the inner peripheral portion, which is the electrode main body portion, comes into contact with the metal pipe material. As a result, the contact state between the contact surface and the metal pipe material can be improved as compared with the case where the easily deformable conductive material comes into direct contact with the metal pipe material.

The electrode may be composed of two divided members so as to sandwich the metal pipe material. In this case, the contact surface can be brought into contact with the metal pipe material by sandwiching the metal pipe material between the divided electrodes.

The electrode is integrally formed over the entire circumference in the circumferential direction, and has an insertion portion into which the metal pipe material can be inserted from the axial direction of the metal pipe material. In this case, by inserting the metal pipe material into the insertion portion, the contact surface can be brought into contact with the metal pipe material.

The conductive member may be configured by laminating a plurality of conductive plate materials in the radial direction. In this case, the plurality of conductive plates can be deformed so as to reduce the gap between the plates.

According to the present invention, it is possible to provide an energization heating device capable of improving the performance of energization heating.

It is a schematic block diagram of the molding apparatus which adopted the energization heating apparatus which concerns on this embodiment. An enlarged view of the periphery of the electrode, (a) is a view showing a state in which the electrode holds a metal pipe material, (b) is a view showing a state in which a sealing member is pressed against the electrode, and (c) is a front view of the electrode. Is. It is an enlarged sectional view which shows the electrode of the energization heating apparatus. FIG. 3 is a cross-sectional view taken along the line IV-IV of FIG. 5 (a) is a perspective view showing a multi-contact in a state of being extended in a plane, and FIG. 5 (b) is a cross-sectional view taken along the line Vb-Vb of FIG. 5 (a). It is an enlarged cross-sectional view which shows the state which the electrode is opened. It is an enlarged sectional view which shows the electrode of the energization heating apparatus which concerns on a modification. It is an enlarged sectional view which shows the electrode of the energization heating apparatus which concerns on a modification. It is a figure which shows the electrode of the energization heating apparatus which concerns on a modification, and is the figure which corresponds to FIG. It is an enlarged sectional view which shows the electrode of the energization heating apparatus which concerns on a modification.

Hereinafter, preferred embodiments of the molding apparatus according to the present invention will be described with reference to the drawings. In each figure, the same parts or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.

<Structure of molding equipment>
FIG. 1 is a schematic configuration diagram of a molding device to which the energization heating device according to the present embodiment is applied. As shown in FIG. 1, the molding apparatus 10 for molding a metal pipe includes a molding mold 13 including an upper mold 12 and a lower mold 11, and a drive mechanism 80 for moving at least one of the upper mold 12 and the lower mold 11. , A pipe holding mechanism 30 for holding the metal pipe material 14 arranged between the upper mold 12 and the lower mold 11, and an energizing heating device for energizing and heating the metal pipe material 14 held by the pipe holding mechanism 30. A gas supply unit 60 for supplying high-pressure gas (gas) into a metal pipe material 14 held between the upper mold 12 and the lower mold 11 and heated, and a metal pipe held by a pipe holding mechanism 30. A pair of gas supply mechanisms 40 and 40 for supplying gas from the gas supply unit 60 into the material 14 and a water circulation mechanism 72 for forcibly cooling the molding mold 13 with water are provided, and the drive mechanism 80 is driven. , The drive of the pipe holding mechanism 30, the drive of the energization heating device 50, and the control unit 70 for controlling the gas supply of the gas supply unit 60, respectively.

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 has, for example, a rectangular cavity (recess) 16 on the upper surface thereof. A cooling water passage 19 is formed in the lower mold 11, and a thermocouple 21 inserted from below is provided substantially in the center. The thermocouple 21 is supported by a spring 22 so as to be vertically movable.

Further, a space 11a is provided near the left and right ends (left and right ends in FIG. 1) of the lower mold 11, and the electrodes 17 and 18 (lower) described later, which are movable parts of the pipe holding mechanism 30, are provided in the space 11a. Side electrodes) and the like are arranged so that they can move up and down. Then, by placing the metal pipe material 14 on the lower electrodes 17 and 18, the lower electrodes 17 and 18 come into contact with the metal pipe material 14 arranged between the upper mold 12 and the lower mold 11. do. As a result, the lower electrodes 17 and 18 are electrically connected to the metal pipe material 14.

The lower electrodes 17 and 18 are fixed to an advancing / retreating rod 95 which is a movable part of an actuator (not shown) constituting the pipe holding mechanism 30. This actuator is for moving the lower electrodes 17, 18 and the like up and down, 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 side of the molding mold 13, is fixed to a slide 81, which will be described later, which constitutes the drive mechanism 80. The upper mold 12 is composed of a large steel block, has a cooling water passage 25 formed therein, and has, 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.

Similar to 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, and the space 12a is described later as a movable portion of the pipe holding mechanism 30. Electrodes 17, 18 (upper electrode) and the like are arranged so as to be able to move up and down. Then, in a state where the metal pipe material 14 is placed on the lower electrodes 17 and 18, the upper electrodes 17 and 18 are arranged between the upper mold 12 and the lower mold 11 by moving downward. Contact the metal pipe material 14. As a result, the upper electrodes 17 and 18 are electrically connected to the metal pipe material 14.

The upper electrodes 17 and 18 are fixed to the advancing / retreating rod 96 which is a movable part of the actuator constituting the pipe holding mechanism 30. This actuator is for moving the upper electrodes 17, 18 and the like up and down, and the fixed portion 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 contact surface 18a corresponding to the outer peripheral surface of the metal pipe material 14 is formed on each of the surfaces of the electrodes 18 and 18 facing each other (see FIG. 2). The metal pipe material 14 can be placed so as to fit into the contact surface 18a. Further, on the front surface of the electrode 18 (the surface in the outer direction of the mold), a tapered surface 18b is formed whose circumference is inclined in a tapered shape toward the contact surface 18a and is recessed. Therefore, when the metal pipe material 14 is sandwiched from the vertical direction by the right side portion of the pipe holding mechanism 30, it is configured so that the outer periphery of the right end portion of the metal pipe material 14 can be surrounded so as to be in close contact with the entire circumference. ing.

In the left side portion of the pipe holding mechanism 30, a semicircular contact surface 17a corresponding to the outer peripheral surface of the metal pipe material 14 is formed on each of the surfaces of the electrodes 17 and 17 facing each other (see FIG. 2). The metal pipe material 14 can be placed so as to fit into the contact surface 17a. Further, on the front surface of the electrode 17 (the surface in the outer direction of the mold), a tapered surface 17b is formed whose circumference is inclined in a tapered shape toward the contact surface 17a and is recessed. Therefore, when the metal pipe material 14 is sandwiched from the vertical direction by the left side portion of the pipe holding mechanism 30, it is configured so that the outer periphery of the left end portion of the metal pipe material 14 can be surrounded so as to be in close contact with the entire circumference. ing.

As shown in FIG. 1, the drive mechanism 80 includes a slide 81 for moving the upper die 12 so that the upper die 12 and the lower die 11 are aligned with each other, and a shaft 82 for generating 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, and the eccentric crank 82a that protrudes from the left-right end and extends in the left-right direction at a position separated from the axis thereof. Have. The eccentric crank 82a and the rotating shaft 81a provided on 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 rotation of the shaft 82 is controlled by the control unit 70 to change the height of the eccentric crank 82a in the vertical direction, and the position change of the eccentric crank 82a is transmitted to the slide 81 via the connecting rod 83. Thereby, the vertical movement of the slide 81 can be controlled. Here, the swing (rotational motion) of the connecting rod 83 generated 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 drive of a motor or the like controlled by, for example, the control unit 70.

The energization heating device 50 includes a power supply unit 55 and a bus bar 52 that electrically connects the power supply unit 55 and the electrodes 17 and 18. The power supply unit 55 includes a DC power supply and a switch, and can energize the metal pipe material 14 via the bus bar 52 and the electrodes 17 and 18 in a state where the electrodes 17 and 18 are electrically connected to the metal pipe material 14. Has been done. The bus bar 52 is connected to the lower electrodes 17 and 18 here.

In this energization heating device 50, the direct current output from the power supply unit 55 is transmitted by the bus bar 52 and input to the electrode 17. Then, the direct current passes through the metal pipe material 14 and is input to the electrode 18. Then, the direct current C is transmitted by the bus bar 52 and input to the power supply unit 55.

Returning to FIG. 1, each of the pair of gas supply mechanisms 40 is connected to the cylinder unit 42, the cylinder rod 43 that moves forward and backward according to the operation of the cylinder unit 42, and the tip of the cylinder rod 43 on the pipe holding mechanism 30 side. It also has a sealing member 44. The cylinder unit 42 is placed 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 surfaces 17b and 18b of the electrodes 17 and 18 (see FIG. 2). The seal member 44 extends from the cylinder unit 42 side toward the tip, and as shown in FIGS. 2 (a) and 2 (b), 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 for storing the gas supplied by the gas source 61, a first tube 63 extending from the accumulator 62 to the cylinder unit 42 of the gas supply mechanism 40, and a first tube 63 thereof. The pressure control valve 64 and the switching valve 65 interposed in the 1 tube 63, the second tube 67 extending from the accumulator 62 to the gas passage 46 formed in the seal member 44, and the second tube 67. It is composed of a pressure control valve 68 and a check valve 69 provided. The pressure control valve 64 serves to supply the cylinder unit 42 with a gas having an operating pressure adapted to the pushing force of the sealing 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 interposed 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 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. Further, the control unit 70 acquires temperature information from the thermocouple 21 by transmitting information from (A) shown in FIG. 1, and controls the drive mechanism 80, the power supply unit 55, and the like.

The water circulation mechanism 72 includes a water tank 73 for storing water, a water pump 74 that pumps up the water stored in the water tank 73, pressurizes it, and sends it 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, it is permissible to interpose a cooling tower that lowers the water temperature or a filter that purifies the water in the pipe 75.

<Metal pipe molding method using a molding device>
Next, a method of forming a metal pipe using the forming apparatus 10 will be described. First, a hardenable steel grade cylindrical metal pipe material 14 is prepared. The metal pipe material 14 is placed (loaded) on the electrodes 17 and 18 provided on the lower mold 11 side by using, for example, a robot arm or the like. Since the contact surfaces 17a and 18a are formed on the electrodes 17 and 18, the metal pipe material 14 is positioned by the contact surfaces 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 upper electrodes 17, 18 and the like held on the slide 81 side are moved to the lower mold 11 side by the drive of the drive mechanism 80, and the upper electrode 17 and the like included in the pipe holding mechanism 30 are included. By operating an actuator that allows the metal pipe material 14 and the lower electrodes 17, 18 and the like to move forward and backward, the vicinity of both ends of the metal pipe material 14 is sandwiched by the pipe holding mechanism 30 from above and below. This sandwiching is performed in such a manner that the metal pipe material 14 is in close contact with the metal pipe material 14 over the entire circumference near both ends due to the presence of the concave grooves formed on the contact surfaces 17a and 18a formed on the electrodes 17 and 18. It becomes.

At this time, as shown in FIG. 2A, the end portion of the metal pipe material 14 on the electrode 18 side has a contact surface 18a and a tapered surface 18b of the electrode 18 in the extending direction of the metal pipe material 14. It protrudes toward the seal member 44 side from the boundary of the above. Similarly, the end portion of the metal pipe material 14 on the electrode 17 side protrudes toward the seal member 44 from the boundary between the contact surface 17a and the tapered surface 17b of the electrode 17 in the extending direction of the metal pipe material 14. Further, the lower surfaces of the upper electrodes 17 and 18 and the upper surfaces of the lower electrodes 17 and 18 are in contact with each other, respectively. However, the configuration is not limited to the structure in which the metal pipe material 14 is in close contact with the entire circumference of both ends, and the electrodes 17 and 18 may be in contact with a part of the metal pipe material 14 in the circumferential direction.

Subsequently, the control unit 70 heats the metal pipe material 14 by controlling the energization heating device 50. Specifically, the control unit 70 controls the power supply unit 55 of the energization heating device 50 to supply electric power. Then, the electric power transmitted to the lower electrodes 17 and 18 via the bus bar 52 is supplied to the upper electrodes 17 and 18 and the metal pipe material 14 sandwiching the metal pipe material 14, and exists in the metal pipe material 14. Due to the resistance, the metal pipe material 14 itself generates heat due to Joule heat. That is, the metal pipe material 14 is in an energized heating state.

Subsequently, the molding die 13 is closed with respect to the heated metal pipe material 14 under 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 arranged and sealed in the cavity portion between the lower mold 11 and the upper mold 12.

After that, by operating the cylinder unit 42 of the gas supply mechanism 40, the sealing member 44 is advanced to seal both ends of the metal pipe material 14. At this time, as shown in FIG. 2B, the sealing member 44 is pressed against the end portion of the metal pipe material 14 on the electrode 18 side, so that the contact surface 18a of the electrode 18 and the tapered surface 18b are more than the boundary. The portion protruding toward the seal member 44 is deformed into a funnel shape along the tapered surface 18b. Similarly, when the seal member 44 is pressed against the end portion of the metal pipe material 14 on the electrode 17 side, a portion of the metal pipe material 14 protruding toward the seal member 44 side from the boundary between the contact surface 17a and the tapered surface 17b of the electrode 17 is formed. It is deformed into a funnel shape along the tapered surface 17b. After the sealing is completed, high-pressure gas is blown into the metal pipe material 14 to form the metal pipe material 14 softened by heating 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 thermally expands. Therefore, for example, the gas to be supplied 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 blow-molded and swollen metal pipe material 14 contacts the cavity 16 of the lower mold 11 and is rapidly cooled, and at the same time, it contacts the cavity 24 of the upper mold 12 and is rapidly cooled (the upper mold 12 and the lower mold 11 are quenched). Since the heat capacity is large and controlled at a low temperature, if the metal pipe material 14 comes into contact with the metal pipe material 14, the heat on the surface of the pipe 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 into martensite (hereinafter, the transformation of austenite into martensite is referred to as martensitic transformation). Since the cooling rate decreased in the latter half of cooling, martensite transforms into another structure (troostite, sorbite, etc.) by reheating. Therefore, it is not necessary to perform a separate tempering process. Further, in the present embodiment, cooling may be performed by supplying a cooling medium, for example, into the cavity 24, instead of cooling the mold or in addition to cooling the mold. For example, until the temperature at which martensitic transformation begins, the metal pipe material 14 is brought into contact with the mold (upper mold 12 and lower mold 11) for cooling, and then the mold is opened and the cooling medium (cooling gas) is used as the metal pipe material. Martensitic transformation may be generated by spraying on 14.

As described above, the metal pipe material 14 is blow-molded, then cooled, and the mold is opened to obtain, for example, a metal pipe having a substantially rectangular tubular body portion.

<Energizing heating device>
Next, with reference to FIGS. 3 and 4, a characteristic portion of the energization heating device 50 according to the present embodiment will be described. FIG. 3 is an enlarged cross-sectional view showing the electrode 18 of the energization heating device 50. FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. Although only the electrode 18 is shown in FIGS. 3 and 4, the electrode 17 also has the same configuration. Therefore, the following description is also valid for the electrode 17, and the description of the electrode 17 will be omitted. Further, the electrode 18 is composed of two divided members so as to sandwich the metal pipe material 14. In the following description, the upper electrode 18 will be referred to as an electrode 18A, and the lower electrode 18 will be referred to as an electrode 18B.

Further, the center line CL in the figure corresponds to the center line of the metal pipe material 14 at the time of energization heating. The center line CL is the center line of the above-mentioned contact surfaces 18a and 18a when the electrodes 18A and 18B are closed and the metal pipe material 14 is sandwiched between them. The contact surface 18a comes into contact with the outer peripheral surface 14a of the metal pipe material 14 when energized and heated. When the electrodes 18A and 18B are closed and the metal pipe material 14 is sandwiched, the contact surfaces 18a and 18a form a semi-cylindrical surface with the center line CL as the central axis. The surfaces of the electrodes 18A and 18B facing each other are flat surfaces 18e and 18e in which the portions other than the contact surfaces 18a and 18a are in contact with each other when the metal pipe material 14 is sandwiched. The electrodes 18A and 18B have end faces 18c and 18d facing in the axial direction in which the center line CL extends. The end surface 18c is a surface arranged on the mold 13 side. The end surface 18d is a surface arranged on the opposite side of the mold 13. The tapered surface 18b is formed on the inner peripheral side of the end surface 18d.

As shown in FIGS. 3 and 4, the upper electrode 18A includes an electrode main body portion 110 and a displacement allowable portion 120. The electrode body 110 is a portion formed of a conductive electrode material. The electrode main body 110 is a highly rigid member formed by forming an electrode material into a predetermined shape. The electrode main body 110 has an inner peripheral portion 112 and an outer peripheral portion 113, which are divided from each other and configured as separate pieces. Since the lower electrode 18B has a shape that is vertically symmetrical with the upper electrode 18A, the description thereof will be omitted.

The inner peripheral portion 112 is a member that constitutes a part of the inner peripheral side of the electrode 18A. The inner peripheral portion 112 is composed of a semi-cylindrical member. The inner peripheral surface 112a of the inner peripheral portion 112 is formed as the above-mentioned contact surface 18a. The outer peripheral surface 112b of the inner peripheral portion 112 has a diameter larger than that of the contact surface 18a and has a semi-cylindrical shape parallel to the contact surface 105. The end faces 112e at both ends of the inner peripheral portion 112 in the circumferential direction form a part of the plane 18e of the above-mentioned electrode 18A (see FIG. 4). The inner peripheral portion 112 has end faces 112c and 112d in the axial direction in which the center line CL extends. The end face 112c constitutes a part of the end face 18c of the electrode 18A. The end face 112d constitutes a part of the end face 18d of the electrode 18A. Further, the inner peripheral portion 112 has a tapered surface 18b of the electrode 18A.

The outer peripheral portion 113 is a member that constitutes a part of the outer peripheral side of the electrode 18A. The outer peripheral portion 113 is configured by forming an inner peripheral surface 113a, which is a semi-cylindrical surface, with respect to the planar end surface 113e on the lower end side (see FIG. 4). The inner peripheral surface 113a is substantially parallel to the outer peripheral surface 112b of the inner peripheral portion 112 in a state of being separated from the outer peripheral surface 112b. Further, the end face 113e constitutes a part of the plane 18e of the above-mentioned electrode 18A (see FIG. 4). The outer peripheral portion 113 has end faces 113c and 113d in the axial direction in which the center line CL extends. The end face 113c constitutes a part of the end face 18c of the electrode 18A. The end face 113d constitutes a part of the end face 18d of the electrode 18A.

The displacement allowable portion 120 is a portion that allows displacement of the contact surface 18a that comes into contact with the outer peripheral surface 14a of the metal pipe material 14. The displacement allowable portion 120 is formed between the inner peripheral surface 113a of the outer peripheral portion 113 and the outer peripheral surface 112b of the inner peripheral portion 112. As a result, the outer peripheral portion 113 is arranged on the outer peripheral side of the displacement allowable portion 120, and the inner peripheral portion 112 is arranged on the inner peripheral side of the displacement allowable portion 120. The displacement allowable portion 120 allows the contact surface 18a to be displaced toward the outer peripheral side. That is, when the contact surface 18a is pushed by the metal pipe material 14 and receives a load radially outward, the displacement allowable portion 120 allows the inner peripheral portion 112 together with the contact surface 18a to be displaced radially outward. .. At this time, the displacement allowable portion 120 generates a reaction force toward the inner peripheral side with respect to the displacement.

The displacement allowable portion 120 has a conductive member 121 that is more easily deformed in the radial direction than the electrode main body portion 110. The conductive member 121 is arranged so as to extend in the circumferential direction in the space between the inner peripheral surface 113a of the outer peripheral portion 113 and the outer peripheral surface 112b of the inner peripheral portion 112. The conductive member 121 maintains a state in which the outer peripheral portion 113 and the inner peripheral portion 112 are electrically connected before and after the deformation. The conductive member 121 is supported on the inner peripheral surface 113a of the outer peripheral portion 113 on the outer peripheral side. Further, the conductive member 121 elastically deforms on the inner peripheral side when pressed by the inner peripheral portion 112. Therefore, the conductive member 121 absorbs the displacement of the contact surface 18a toward the outer peripheral side via the outer peripheral surface 112b of the inner peripheral portion 112, and generates an elastic force as a reaction force against the displacement. Here, the amount of deformation of the conductive member 121 is different from the amount of deformation when, for example, an insulating layer having a lower rigidity than the electrode material undergoes minute deformation, and is at least the dimensional tolerance of the metal pipe material 14. The amount of deformation is such that the displacement can be absorbed.

The conductive member 121 may be configured by, for example, a multi-contact. A multi-contact is a band-shaped member made of a conductive material, and is a member in which a plurality of shape patterns capable of generating elastic forces are arranged in the longitudinal direction. An example of multi-contact is shown in FIG. 5 (a) is a perspective view showing the multi-contact 130 in a state of being extended in a plane, and FIG. 5 (b) is a cross-sectional view taken along the line Vb-Vb of FIG. 5 (a). As shown in FIG. 5, the multi-contact 130 includes a base portion 131 and an elastic portion 132. The base portion 131 is a portion extending in a band shape. The multi-contact 130 has a pair of base portions 131 so as to be separated from each other in the width direction and face each other. A plurality of elastic portions 132 are formed so as to be connected to the base portion 131 so that the base portions 131 are arranged in the extending direction. The elastic portion 132 is provided so as to be bridged between the pair of base portions 131 in the width direction. A gap 133 is formed between the adjacent elastic portions 132. The elastic portion 132 is twisted so as to protrude from the main surfaces 131a and 131b of the base portion 131 to both sides in the thickness direction of the base portion 131. The edge portion 132a of the elastic portion 132 protrudes from the main surface 131a, and the edge portion 132b protrudes from the main surface 131b.

When the multi-contact 130 is incorporated in the displacement allowable portion 120, the space between the inner peripheral surface 113a of the outer peripheral portion 113 and the outer peripheral surface 112b of the inner peripheral portion 112 in a curved state so as to draw a semi-circular arc. Placed inside. In FIG. 5, the base portion 131 extends in a plane shape, but when incorporated in the displacement allowable portion 120, it extends in a strip shape along the circumferential direction. Further, when the plurality of elastic portions 132 are incorporated into the displacement allowable portion 120, they are arranged so as to be arranged in the circumferential direction. Further, the edge portion 132a of the elastic portion 132 abuts on the inner peripheral surface 113a of the outer peripheral portion 113, and the edge portion 132b of the elastic portion 132 abuts on the outer peripheral surface 112b of the inner peripheral portion 112. Then, when the multi-contact 130 is pressed toward the outer peripheral side by the inner peripheral portion 112, the elastic portion 132 is deformed so as to generate an elastic force. Specifically, the elastic portion 132 is deformed so that the edge portions 132a and 132b approach the base portion 131 so that the amount of twist with respect to the base portion 131 is reduced. At this time, the elastic portion 132 restores to the original state and generates an elastic force so as to return to the original twist amount.

The displacement allowable portion 120 may have one multi-contact 130 in the axial direction, or may have a plurality of multi-contacts 130. Further, the displacement allowable portion 120 may have a multi-contact 130 extending continuously from one plane 18e to the other plane 18e, but has a multi-contact 130 divided into a plurality of parts in the circumferential direction. May be good.

The type of multi-contact that can be used as the conductive member 121 is not particularly limited. For example, the shape of the elastic portion between the pair of base portions is not particularly limited. For example, the elastic portion may be formed so as to protrude from only one main surface of the base portion. Further, the elastic portion does not have to have a shape in which the plate is twisted, and may have a shape in which the plate is bent or curved, for example. The elastic portion may be curved or bent in a mountain shape from one base portion to the other base portion. Further, the type does not have to extend the elastic portion between the pair of base portions, and may be a type in which the elastic portion protrudes from one base portion to both sides in the axial direction. Further, a coiled multi-contact may be adopted.

As shown in FIGS. 3 and 4, the conductive member 121 is supported by the support member 122 on both ends in the axial direction. The support member 122 is a member that extends radially on the end faces 18c and 18d so as to be bridged between the outer peripheral portion 113 and the inner peripheral portion 112. A plurality of support members 122 are provided in a state of being separated from each other in the circumferential direction. The support member 122 may be formed of either a conductive material or an insulating material, but is preferably formed of an insulating material such as ceramic. When the support member 122 is made of an insulating material, it is possible to suppress the influence of the support member 122 on the energization state by the conductive member 121 between the outer peripheral portion 113 and the inner peripheral portion 112. Further, the support member 122 is a member that is easily deformed to the extent that it can follow the deformation of the conductive member 121.

The operation when the metal pipe material 14 is sandwiched between the electrodes 18A and 18B will be described with reference to FIGS. 3 and 6. First, as shown in FIG. 6, the electrodes 18A and 18B are set to be open. At this time, the plane 18e of the electrode 18A and the plane 18e of the electrode 18B (see FIG. 4) are arranged so as to be separated from each other in the vertical direction. In this state, the end portion of the metal pipe material 14 is arranged between the contact surface 18a of the electrode 18A and the contact surface 18a of the electrode 18B. In this state, the electrodes 18A and 18B are closed as shown in FIG. The metal pipe material 14 contacts the contact surface 18a of the upper electrode 18A at the upper half of the outer peripheral surface 14a, and contacts the contact surface 18a of the lower electrode 18B at the lower half of the outer peripheral surface 14a. At this time, when the diameter of the metal pipe material 14 is large, the inner peripheral portion 112 is relatively pushed toward the outer peripheral side by the metal pipe material 14 via the contact surface 18a. At this time, the displacement allowable portion 120 allows the contact surface 18a to be displaced toward the outer peripheral side, and the outer peripheral portion 113 is deformed so as to move toward the outer peripheral side.

Next, the operation / effect of the energization heating device 50 according to the present embodiment will be described.

In the energization heating device 50, the electrode 18 includes, in addition to the electrode main body portion 110, a displacement allowable portion 120 that allows displacement of the contact surface 18a that comes into contact with the outer peripheral surface 14a of the metal pipe material 14. The displacement allowable portion 120 has a conductive member 121 that is more easily deformed in the radial direction of the contact surface 18a than the electrode main body portion 110. For example, when the outer diameter of the metal pipe material 14 is large due to the influence of dimensional tolerance or the like, the conductive member 121 is deformed in the radial direction of the contact surface 18a. As a result, the displacement allowable portion 120 can allow the displacement of the contact surface 18a and absorb the dimensional tolerance of the metal pipe material 14. Therefore, a good contact state between the contact surface 18a and the metal pipe material 14 can be maintained. As a result, the performance of energization heating can be improved.

The conductive member 121 includes a base portion 131 extending in a band shape along the circumferential direction of the contact surface 18a, and a plurality of elastic portions 132 connected to the base portion 131 and formed so as to line up in the circumferential direction. By being pressed in the radial direction, an elastic force is generated in the radial direction. When the contact surface 18a comes into contact with the metal pipe material 14 having a large outer diameter, the elastic portion 132 of the conductive member 121 is pressed in the radial direction. At this time, the conductive member 121 can press the contact surface 18a against the metal pipe material 14 by generating an elastic force while the metal pipe material 14 absorbs the dimensional tolerance of the metal pipe material 14. Thereby, a good contact state between the contact surface 18a and the metal pipe material 14 can be maintained.

The electrode main body 110 has an outer peripheral portion 113 arranged on the outer peripheral side of the displacement allowable portion 120, and an inner peripheral portion 112 arranged on the inner peripheral side of the displacement allowable portion 120 to form a contact surface 18a. .. In this case, the inner peripheral portion 112, which is the electrode main body portion 110, comes into contact with the metal pipe material 14. As a result, the contact state between the contact surface 18a and the metal pipe material 14 can be improved as compared with the case where the easily deformable conductive member 121 comes into contact with the metal pipe material 14.

The electrode 18 is composed of two divided members so as to sandwich the metal pipe material 14. In this case, the contact surface can be brought into contact with the metal pipe material 14 by sandwiching the metal pipe material 14 between the divided electrodes 18A and 18B.

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

In the above-described embodiment, the electrode is divided into two in the vertical direction, but the number of divided electrodes in the circumferential direction is not particularly limited. For example, the electrodes may be divided into three or more in the circumferential direction. Further, the electrodes do not have to be divided in the circumferential direction. For example, the configuration shown in FIG. 7 may be adopted. As described above, the electrodes 218 are integrally formed up and down in the circumferential direction over the entire circumference. The electrode 218 has an insertion portion 240 into which the metal pipe material 14 can be inserted from the axial direction of the metal pipe material 14. The electrode 218 has a structure in which the electrode 18A and the electrode 18B shown in FIG. 3 are fixed to each other by planes 18e and 18e. Therefore, the electrode 218 includes a ring-shaped inner peripheral portion 212, a ring-shaped displacement allowable portion 220, and an outer peripheral portion 213 having a circular through hole. The electrode main body 210 has an inner peripheral portion 212 and an outer peripheral portion 213. The displacement allowable portion 220 has an annular conductive member 221. The insertion portion 240 is composed of a contact surface 218a on the inner peripheral side of the ring-shaped inner peripheral portion 212. The end portion of the metal pipe material 14 is aligned with the insertion portion 240 as shown in FIG. 7A, and then inserted into the insertion portion 240 as shown in FIG. 7B. Such an electrode 218 may be incorporated in the molding apparatus 10 shown in FIG. 1, but may be applied to a heating device provided outside the molding apparatus 10. For example, the electrode 218 may be supported by an arm or the like and approach the end portion of the metal pipe material 14, and the end portion may be inserted into the insertion portion 240.

As described above, the electrode 218 is integrally formed over the entire circumference in the circumferential direction, and has an insertion portion 240 into which the metal pipe material 14 can be inserted from the axial direction of the metal pipe material 14. In this case, by inserting the metal pipe material 14 into the insertion portion 240, the contact surface 218a can be brought into contact with the metal pipe material.

Further, the conductive member of the displacement allowable portion may be in direct contact with the outer peripheral surface 14a of the metal pipe material 14. As shown in FIG. 8, the electrode 318 has a displacement allowable portion 320 on the inner peripheral surface of the electrode main body portion 310. The conductive member 321 of the displacement allowable portion 320 comes into direct contact with the outer peripheral surface 14a of the metal pipe material 14. Both ends of the conductive member 321 in the axial direction may be supported by the insulating portion 330 incorporated in the electrode 318. The electrodes 318 may be integrated in the circumferential direction or may be divided.

Further, the conductive member may be a member other than the multi-contact as long as it is composed of a member having conductivity and can tolerate the displacement of the contact surface 18a. For example, the displacement allowable portion may be configured by laminating a plurality of conductive plates in the radial direction. In the electrode 318 shown in FIG. 9, a conductive member 321 is adopted as a member constituting the displacement allowable portion 320. The conductive member 321 is configured by laminating a conductive plate material 321a curved in a semi-cylindrical shape. The conductive member 321 is a so-called corpel (shunt) member. The plate material 321a constituting the conductive member 321 has a portion curved in a semi-cylindrical shape and a portion extending in a flat plate shape from both ends of the portion. Further, the flat plate-shaped portion is electrically connected to another plate material 321a by the connecting member 321b. Since a slight gap is formed between the plate members 321a, the conductive member 321 can be elastically deformed in the radial direction. The conductive member 321 shown in FIG. 9 comes into contact with the metal pipe material 14 with the inner peripheral surface of the plate material 321a on the innermost peripheral side as the contact surface. Alternatively, as in the electrode 418 shown in FIG. 10, the conductive member 321 may be arranged between the outer peripheral portion 113 and the inner peripheral portion 112.

As the conductive member, a flat knitted copper coin formed by knitting a copper wire may be adopted instead of the above-mentioned multi-contact or corpel.

In the above-described embodiment, the gas supply mechanism is adopted as the fluid supply unit, but the fluid is not limited to the gas, and a liquid may be supplied.

10 ... Molding device, 14 ... Metal pipe material, 18,218,318,418 ... Electrode, 18a ... Contact surface, 50 ... Energizing heating device, 110,310 ... Electrode body, 112,212 ... Inner circumference, 113, 213 ... outer peripheral portion, 120, 220, 320 ... displacement allowable portion, 121, 321 ... conductive member, 130 ... multi-contact, 131 ... base portion, 132 ... elastic portion, 240 ... insertion portion, 321a ... plate material.

Claims (6)

An energizing heating device that energizes and heats the metal pipe by bringing an electrode into contact with the metal pipe material.
The electrode is
The electrode body formed of the electrode material and the electrode body
A displacement permissible portion that allows displacement of the contact surface in contact with the outer peripheral surface of the metal pipe material is provided.
The displacement allowable portion is an energization heating device having a conductive member that is more easily deformed in the radial direction of the contact surface than the electrode main body portion. The conductive member includes a base portion extending in a band shape along the circumferential direction of the contact surface, and a plurality of elastic portions connected to the base portion and formed so as to line up in the circumferential direction.
The energization heating device according to claim 1, wherein the elastic portion is pressed in the radial direction to generate an elastic force in the radial direction. The electrode body is
The outer peripheral portion arranged on the outer peripheral side of the displacement allowable portion and the outer peripheral portion
The energization heating device according to claim 1 or 2, further comprising an inner peripheral portion formed on the inner peripheral side of the displacement allowable portion and having the contact surface formed therein. The energization heating device according to any one of claims 1 to 3, wherein the electrode is composed of two divided members so as to sandwich the metal pipe material. Any one of claims 1 to 3, wherein the electrode is integrally formed over the entire circumference in the circumferential direction of the contact surface, and has an insertion portion into which the metal pipe material can be inserted from the axial direction of the metal pipe material. The energizing heating device according to the section. The energization heating device according to any one of claims 1 to 4, wherein the conductive member is configured by laminating a plurality of conductive plate materials in the radial direction.

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