JP6651415B2 - Molding equipment - Google Patents

Description

  The present invention relates to a molding device.

  2. Description of the Related Art Conventionally, there has been known a molding apparatus for performing blow molding by closing a metal pipe with a mold. For example, a molding device disclosed in Patent Document 1 includes a mold and a gas supply unit that supplies gas into a metal pipe material. In this molding apparatus, the metal pipe material is placed in a mold, and the metal pipe material is supplied with a gas from a gas supply unit to expand the metal pipe material in a state where the mold is closed. Form into a shape corresponding to the shape. In this molding apparatus, before the metal pipe material is expanded, the metal pipe material is held by the electrodes, and the metal pipe material is electrically heated by the electrodes.

JP 2012-000654 A

  In the above-described molding apparatus, when the metal pipe material is energized and heated by the electrodes, if the energization is rapidly performed, there is a problem that the eddy current generated in the molding die becomes large. When the eddy current increases, for example, there is a possibility that adverse effects due to heat accumulation in the molding die may occur. Therefore, it has been demanded to reduce the eddy current in the molding die.

  An object of the present invention is to provide a molding apparatus capable of reducing eddy current in a molding die.

  A molding apparatus according to the present invention is a molding apparatus for molding a metal pipe by expanding a metal pipe material, at least one of which is movable, and a first mold and a second mold for molding the metal pipe. A molding die having a pair of electrodes that heats the metal pipe material by energizing the metal pipe material, and a gas supply unit that expands by supplying gas into the heated metal pipe material, The molding die has an eddy current suppressing unit that suppresses generation of eddy current in the molding die.

  According to such a molding apparatus, the metal pipe material expands by heating by energizing the pair of electrodes to the metal pipe material, and supplying the gas into the heated metal pipe material by the gas supply unit. The metal pipe is formed by contact with the forming die. Here, when a pair of electrodes conducts electricity to the metal pipe material, an eddy current is generated in the molding die. However, since the molding die has the eddy current suppressing portion that suppresses the generation of the eddy current in the molding die, the generation of the eddy current in the molding die is suppressed. As described above, the eddy current in the molding die can be reduced.

  In addition, the pair of electrodes are disposed at one end and the other end of the metal pipe material in the stretching direction at the time of energization, respectively, and the eddy current suppressing unit suppresses the generation of the eddy current flowing in the stretching direction in the molding die. May be. In this case, since the pair of electrodes are disposed at one end and the other end in the extending direction of the metal pipe, an eddy current is easily generated in the extending direction in the molding die. Therefore, the eddy current suppressing section suppresses the generation of the eddy current flowing in the extending direction in the molding die, so that the eddy current in the molding die can be efficiently reduced.

  Further, the eddy current suppressing section may be constituted by a high-resistance section having a higher resistance than a metal material forming the molding die. In this case, since the eddy current is blocked by the high resistance portion, it becomes difficult for the eddy current to flow, and generation of the eddy current can be suppressed.

  The high resistance portion may be covered with a metal material on the cavity side of the molding die. In this case, since the portion where the high resistance portion is exposed is not provided on the cavity side of the molding die, the metal pipe is prevented from contacting the high resistance portion when the metal pipe is molded by the molding die, and the molding is performed. Performance can be improved.

  The molding apparatus further includes a holder that supports the molding die, and the molding die is provided on a plurality of divided members divided by the high-resistance portion, and on a mounting portion side of the holder and the molding die, And a base member for supporting the divided members. In this case, the plurality of divided members divided by the high resistance portion are supported by the base member on the side of the mounting portion to the holder. Therefore, the positional accuracy between the divided members can be improved.

  According to the present invention, eddy currents in a molding die can be reduced.

It is a schematic structure figure of a shaping device. FIG. 2 is a cross-sectional view of the blow molding die taken along the line II-II shown in FIG. 1. It is an enlarged view of an electrode periphery, (a) is a figure showing a state where an electrode holds a metal pipe material, (b) is a figure showing a state where a sealing member abuts on an electrode, and (c) is a front view of an electrode. FIG. It is a figure which shows the manufacturing process by a shaping | molding apparatus, (a) is a figure which shows the state in which the metal pipe material was set in the metal mold, and (b) is a figure which shows the state in which the metal pipe material was held by the electrode. is there. It is a figure which shows the outline | summary of the blow molding process by a molding device, and the flow after that. It is a figure which shows operation | movement of a blow molding die, and the change of the shape of a metal pipe material. FIG. 7 is a cross-sectional view of the blow mold along a line VII-VII shown in FIG. 2. It is sectional drawing of the blow molding die of the shaping | molding apparatus which concerns on a modification. FIG. 9 is a cross-sectional view of the blow molding die taken along the line IX-IX shown in FIG. 8.

  Hereinafter, preferred embodiments of a molding apparatus and a molding method according to the present invention will be described with reference to the drawings. In each of the drawings, the same or corresponding portions have the same reference characters allotted, and overlapping description will be omitted.

<Configuration of molding equipment>
FIG. 1 is a schematic configuration diagram of a molding apparatus. As shown in FIG. 1, a molding apparatus 10 for molding a metal pipe 100 (see FIG. 5) includes a pair of an upper mold (first mold) 12 and a lower mold (second mold) 11. Blow mold 13, 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 between the upper mold 12 and the lower mold 11, A heating mechanism 50 for energizing and heating the metal pipe material 14 held by the pipe holding mechanism 30 and a high-pressure gas (gas) in the heated metal pipe material 14 held between the upper mold 12 and the lower mold 11. And a pair of gas supply mechanisms 40 and 40 for supplying the gas from the gas supply unit 60 into the metal pipe material 14 held by the pipe holding mechanism 30, and a blow molding metal. Water cooling the mold 13 That includes a water circulation mechanism 72. Further, the molding apparatus 10 includes a control unit 70 for controlling the driving of the driving mechanism 80, the driving of the pipe holding mechanism 30, the driving of the heating mechanism 50, and the gas supply of the gas supply unit 60, respectively. It is configured.

  The lower mold (second mold) 11 is fixed to a large base 15. The lower mold 11 is formed of a large steel block, and has a cavity 16 on an upper surface thereof. Further, electrode housing spaces 11a are provided near the left and right ends (left and right ends in FIG. 1) of the lower mold 11. The molding apparatus 10 includes a first electrode 17 and a second electrode 18 that are configured to be able to move up and down by an actuator (not shown) in the electrode storage space 11a. On the upper surfaces of the first electrode 17 and the second electrode 18, semicircular concave grooves 17a and 18a corresponding to the lower outer peripheral surface of the metal pipe material 14 are formed, respectively (see FIG. 3C). The metal pipe material 14 can be placed so as to fit into the concave grooves 17a and 18a. The front surface of the first electrode 17 (the surface in the outward direction of the mold) is formed with a tapered concave surface 17b whose periphery is inclined in a tapered shape toward the concave groove 17a. On the outer surface of the mold, there is formed a tapered concave surface 18b whose periphery is inclined in a tapered shape toward the concave groove 18a. In addition, a cooling water passage 19 is formed in the lower mold 11 and includes a thermocouple 21 inserted from below at substantially the center. The thermocouple 21 is vertically movably supported by a spring 22.

  The pair of first and second electrodes 17 and 18 located on the lower mold 11 side constitute a pipe holding mechanism 30, and can move the metal pipe material 14 between the upper mold 12 and the lower mold 11. Can be supported. Further, the thermocouple 21 is merely an example of the temperature measuring means, and may be a non-contact type temperature sensor such as a radiation thermometer or an optical thermometer. If a correlation between the energization time and the temperature can be obtained, it is sufficiently possible to omit the temperature measuring means.

  The upper mold (first mold) 12 is a large steel block having a cavity 24 on the lower surface and a cooling water passage 25 built therein. The upper die 12 has an upper end fixed to the slide 82. The slide 82 to which the upper die 12 is fixed is hung by the pressurizing cylinder 26, and is guided by the guide cylinder 27 so as not to swing sideways.

  Near the left and right ends (left and right ends in FIG. 1) of the upper mold 12, an electrode storage space 12 a similar to that of the lower mold 11 is provided. The molding apparatus 10 includes a first electrode 17 and a second electrode 18 that are configured to be movable up and down by an actuator (not shown), like the lower mold 11, in the electrode housing space 12a. On the lower surfaces of the first and second electrodes 17, 18, semi-circular concave grooves 17a, 18a corresponding to the upper outer peripheral surface of the metal pipe material 14 are formed, respectively (see FIG. 3C). The metal pipe material 14 can be fitted into the concave grooves 17a and 18a. The front surface of the first electrode 17 (the outer surface of the mold) is formed with a tapered concave surface 17b whose periphery is inclined in a tapered shape toward the concave groove 17a and is recessed. The outer surface of the mold) is formed with a tapered concave surface 18b whose periphery is inclined in a tapered shape toward the concave groove 18a. Therefore, the pair of first and second electrodes 17 and 18 located on the upper mold 12 side also constitute the pipe holding mechanism 30, and the metal pipe material 14 is vertically moved by the pair of upper and lower first and second electrodes 17 and 18. When sandwiched from the direction, the outer periphery of the metal pipe material 14 can be surrounded so as to be in close contact with the entire periphery.

  The drive mechanism 80 includes a slide 82 for moving the upper mold 12 so that the upper mold 12 and the lower mold 11 are aligned with each other, a drive unit 81 for generating a driving force for moving the slide 82, A servo motor 83 for controlling the fluid volume. The driving unit 81 is configured by a fluid supply unit that supplies a fluid for driving the pressurizing cylinder 26 (operating oil when a hydraulic cylinder is used as the pressurizing cylinder 26) to the pressurizing cylinder 26.

  The control unit 70 can control the movement of the slide 82 by controlling the amount of fluid supplied to the pressurizing cylinder 26 by controlling the servomotor 83 of the drive unit 81. The driving unit 81 is not limited to the one that applies a driving force to the slide 82 via the pressure cylinder 26 as described above. For example, the drive unit 81 may be configured to mechanically connect a drive mechanism to the slide 82 and directly or indirectly apply the drive force generated by the servo motor 83 to the slide 82. For example, an eccentric shaft, a drive source (for example, a servomotor and a speed reducer) that applies a rotational force for rotating the eccentric shaft, and a conversion unit (for example, a conversion unit that converts the rotational motion of the eccentric shaft into a linear motion and moves a slide) , A connecting rod, an eccentric sleeve, etc.). In the present embodiment, the drive unit 81 does not need to include the servomotor 83.

  FIG. 2 is a cross-sectional view of the blow molding die 13 along the line II-II shown in FIG. As shown in FIG. 2, a step is provided on both the upper surface of the lower die 11 and the lower surface of the upper die 12.

  Assuming that the surface of the cavity 16 at the center of the lower mold 11 is the reference line LV2, a step is formed on the upper surface of the lower mold 11 by the first protrusion 11b, the second protrusion 11c, the third protrusion 11d, and the fourth protrusion 11e. . A first protrusion 11b and a second protrusion 11c are formed on the right side of the cavity 16 (the right side in FIG. 2 and the back side in FIG. 1), and the first protrusion 11b and the second protrusion 11c are formed on the left side (the left side in FIG. 2 and the near side in FIG. 1). Three protrusions 11d and fourth protrusions 11e are formed. The second protrusion 11c is located between the cavity 16 and the first protrusion 11b. The third protrusion 11d is located between the cavity 16 and the fourth protrusion 11e. Each of the second protrusion 11c and the third protrusion 11d protrudes more toward the upper mold 12 than the first protrusion 11b and the fourth protrusion 11e. The protrusion amounts of the first protrusion 11b and the fourth protrusion 11e from the reference line LV2 are substantially the same, and the protrusion amounts of the second protrusion 11c and the third protrusion 11d from the reference line LV2 are substantially the same.

  On the other hand, if the surface of the cavity 24 at the center of the upper die 12 is set as the reference line LV1, a step is formed on the lower surface of the upper die 12 by the first protrusion 12b, the second protrusion 12c, the third protrusion 12d, and the fourth protrusion 12e. ing. The first projection 12b and the second projection 12c are formed on the right side (the right side in FIG. 2) of the cavity 24, and the third projection 12d and the fourth projection 12e are formed on the left side (the left side in FIG. 2) of the cavity 24. The second protrusion 12c is located between the cavity 24 and the first protrusion 12b. The third protrusion 12d is located between the cavity 24 and the fourth protrusion 12e. Each of the first protrusion 12b and the fourth protrusion 12e protrudes toward the lower mold 11 from the second protrusion 12c and the third protrusion 12d. The protrusion amounts of the first protrusion 12b and the fourth protrusion 12e from the reference line LV1 are substantially the same, and the protrusion amounts of the second protrusion 12c and the third protrusion 12d from the reference line LV1 are substantially the same.

  The first protrusion 12b of the upper mold 12 is opposed to the first protrusion 11b of the lower mold 11, and the second protrusion 12c of the upper mold 12 is opposed to the second protrusion 11c of the lower mold 11. The cavity 24 of the upper mold 12 faces the cavity 16 of the lower mold 11, the third projection 12d of the upper mold 12 faces the third projection 11d of the lower mold 11, and the fourth projection 12e of the upper mold 12 It faces the fourth protrusion 11e of the lower die 11. The protrusion amount of the first protrusion 12b with respect to the second protrusion 12c in the upper mold 12 (the protrusion amount of the fourth protrusion 12e with respect to the third protrusion 12d) is equal to the protrusion amount of the second protrusion 11c with respect to the first protrusion 11b in the lower mold 11. (The protrusion amount of the third protrusion 11d with respect to the fourth protrusion 11e). Thus, between the second protrusion 12c of the upper mold 12 and the second protrusion 11c of the lower mold 11, and between the third protrusion 12d of the upper mold 12 and the third protrusion 11d of the lower mold 11, A space is formed when the upper mold 12 and the lower mold 11 are fitted (see FIG. 6C). In addition, a space is formed between the cavity 24 of the upper mold 12 and the cavity 16 of the lower mold 11 when the upper mold 12 and the lower mold 11 are fitted (see FIG. 6C).

  More specifically, at the time before the lower mold 11 and the upper mold 12 are mated during the blow molding and before they are fitted, as shown in FIG. 6B, the surface of the cavity 24 of the upper mold 12 (reference A main cavity portion (first cavity portion) MC is formed between the surface of the cavity 16 of the lower mold 11 (the surface of the reference line LV2) and the surface of the cavity 16 of the lower mold 11 (the surface serving as the line LV1). Further, between the second protrusion 12c of the upper mold 12 and the second protrusion 11c of the lower mold 11, a sub-cavity (the second cavity) having a smaller volume than the main cavity MC communicates with the main cavity MC. The cavity part) SC1 is formed. Similarly, between the third protrusion 12d of the upper mold 12 and the third protrusion 11d of the lower mold 11, a sub-cavity (the second cavity) having a smaller volume than the main cavity MC communicates with the main cavity MC. Is formed. The main cavity part MC is a part for forming the pipe part 100a in the metal pipe 100, and the sub-cavities SC1 and SC2 are parts for forming the flange parts 100b and 100c in the metal pipe 100, respectively (FIGS. 6C and 6C). d)). Then, as shown in FIGS. 6C and 6D, when the lower mold 11 and the upper mold 12 are completely closed (fitted), the main cavity MC and the sub-cavity SC1 are closed. , SC2 are sealed in the lower mold 11 and the upper mold 12.

  As shown in FIG. 1, the heating mechanism 50 includes a power supply 51, a lead 52 extending from the power supply 51 and connected to the first electrode 17 and the second electrode 18, and a switch provided on the lead 52. 53. The control unit 70 can heat the metal pipe material 14 to the quenching temperature (the AC3 transformation point temperature or more) by controlling the heating mechanism 50.

  Each of the pair of gas supply mechanisms 40 includes 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 seal member 44 connected to a tip of the cylinder rod 43 on the pipe holding mechanism 30 side. Having. The cylinder unit 42 is mounted and fixed on the base 15 via the block 41. A tapered surface 45 is formed at the tip of each seal member 44 so as to be tapered. One of the tapered surfaces 45 is formed into a shape that can be fitted and abutted with the tapered concave surface 17b of the first electrode 17, and the other tapered surface 45 is fitted with the tapered concave surface 18b of the second electrode 18. It is configured in a shape that can touch (see FIG. 3). The seal member 44 extends from the cylinder unit 42 side toward the tip. Specifically, as shown in FIGS. 3A and 3B, a gas passage 46 through which the high-pressure gas supplied from the gas supply unit 60 flows is provided.

  Returning to FIG. 1, the gas supply unit 60 includes a gas source 61, an accumulator 62 for storing the gas supplied by the gas source 61, and a first gas extending from the accumulator 62 to the cylinder unit 42 of the gas supply mechanism 40. A tube 63, a pressure control valve 64 and a switching valve 65 provided in the first tube 63, a second tube 67 extending from the accumulator 62 to a gas passage 46 formed in the seal member 44, A pressure control valve 68 and a check valve 69 provided in the second tube 67 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 gas from flowing back in the second tube 67.

  The control unit 70 acquires temperature information from the thermocouple 21 by transmitting information from (A) shown in FIG. 1 and controls the pressurizing cylinder 26, the switch 53, and the like. The water circulation mechanism 72 includes a water tank 73 that stores water, a water pump 74 that pumps up the water stored in the water tank 73, pressurizes the water, and sends the pressurized water to the cooling water passage 19 of the lower mold 11 and the cooling water passage 25 of the upper mold 12. And a pipe 75. Although omitted, a cooling tower for lowering the water temperature or a filter for purifying water may be interposed in the pipe 75.

<Molding method of metal pipe using molding equipment>
Next, a method for forming a metal pipe using the forming apparatus 10 will be described. FIG. 4 shows a process from a pipe feeding step of feeding a metal pipe material 14 as a material to an energizing heating step of feeding and heating the metal pipe material 14. First, a hardening steel type metal pipe material 14 is prepared. As shown in FIG. 4A, the metal pipe material 14 is placed (loaded) on the first and second electrodes 17 and 18 provided on the lower mold 11 using, for example, a robot arm. Since the concave grooves 17a and 18a are formed in the first and second electrodes 17 and 18, respectively, the metal pipe material 14 is positioned by the concave grooves 17a and 18a. Next, the control unit 70 (see FIG. 1) controls the pipe holding mechanism 30 to cause the pipe holding mechanism 30 to hold the metal pipe material 14. Specifically, as shown in FIG. 4 (b), an actuator (not shown) that allows the first electrode 17 and the second electrode 18 to move forward and backward is operated, and the first and second electrodes 17 positioned above and below each other are activated. , 18 approach and abut. By this contact, both ends of the metal pipe material 14 are sandwiched by the first and second electrodes 17 and 18 from above and below. In addition, due to the presence of the concave grooves 17a and 18a respectively formed in the first and second electrodes 17 and 18, this sandwiching is performed in such a manner that the metal pipe material 14 is in close contact over the entire circumference. . However, the configuration is not limited to a configuration in which the first and second electrodes 17 and 18 are in contact with a part of the metal pipe material 14 in a circumferential direction. .

  Subsequently, as shown in FIG. 1, the control unit 70 controls the heating mechanism 50 to heat the metal pipe material 14. Specifically, the control unit 70 turns on the switch 53 of the heating mechanism 50. Then, electric power is supplied from the power source 51 to the metal pipe material 14, and the resistance of the metal pipe material 14 causes the metal pipe material 14 itself to generate heat (Joule heat). At this time, the measured value of the thermocouple 21 is constantly monitored, and the energization is controlled based on the result.

  FIG. 5 shows an outline of a blow molding process by a molding device and a subsequent flow. As shown in FIG. 5, the blow molding die 13 is closed with respect to the heated metal pipe material 14, and the metal pipe material 14 is disposed and sealed in the cavity of the blow molding die 13. Thereafter, both ends of the metal pipe material 14 are sealed by the seal member 44 by operating the cylinder unit 42 of the gas supply mechanism 40 (see also FIG. 3). After the sealing is completed, the blow molding die 13 is closed, and a gas is blown into the metal pipe material 14 to form the metal pipe material 14 softened by heating so as to conform to the shape of the cavity (specific metal pipe material 14). The molding method will be described later).

  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. For this reason, for example, the gas to be supplied is compressed air or compressed nitrogen gas, and the metal pipe material 14 at 950 ° C. is easily expanded by the thermally expanded compressed air, so that the metal pipe 100 can be obtained.

  Specifically, the outer peripheral surface of the blown and expanded metal pipe material 14 contacts the cavity 16 of the lower mold 11 and is rapidly cooled, and at the same time, contacts the cavity 24 of the upper mold 12 and rapidly cooled (the upper mold 12). Since the heat capacity of the lower mold 11 is large and the temperature is controlled to be low, if the metal pipe material 14 comes into contact, the heat of the pipe surface is taken away at a stroke to the mold side), 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, transformation of austenite to martensite is referred to as martensite transformation). In the latter half of the cooling, the cooling rate is reduced, so that the martensite is transformed into another structure (troostite, sorbite, etc.) by reheating. Therefore, it is not necessary to perform a separate tempering process. In the present embodiment, the cooling may be performed by supplying a cooling medium to the metal pipe 100 instead of or in addition to the mold cooling. For example, the metal pipe material 14 is brought into contact with a metal mold (upper mold 12 and lower mold 11) to cool down to a temperature at which martensitic transformation starts, and then the mold is opened and a cooling medium (cooling gas) is supplied to the metal pipe material. By spraying on 14, a martensitic transformation may be generated.

  Next, the configuration of the blow molding die 13 will be described in detail with reference to FIGS. For convenience of description, FIG. 7 also shows the metal pipe material 14. Although FIG. 2 shows a state in which the upper mold 12 and the lower mold 11 are open, the main cavity MC and the subcavities SC1 and SC2 are not formed strictly, but these cavities are formed. The parts corresponding to the die shape to be processed are denoted by reference numerals “MC”, “SC1”, and “SC2”.

  As shown in FIGS. 2 and 7, the blow molding die 13 is formed with an eddy current suppressing portion 110 for suppressing the generation of the eddy current RC in the blow molding die 13. In the present embodiment, the pair of electrodes 17 and 18 are respectively disposed on one end side and the other end side in the extending direction D1 of the metal pipe material 14 during energization. Therefore, as shown in FIG. 7, a current C flows from the electrode 18 to the electrode 17 in the metal pipe material 14 along the stretching direction D1. An eddy current RC is generated in the lower mold 11 and the upper mold 12 due to the electromagnetic induction effect. The eddy current is a vortex induced current generated in a metal by an electromagnetic induction effect when the metal is moved in a strong magnetic field or when the magnetic field near the metal is rapidly changed. The eddy current increases as the moving speed of the metal in the magnetic field increases or the magnetic field change near the metal increases. When such an eddy current is generated, heat is generated by electric resistance, and the temperature of the metal increases. The eddy current suppressing unit 110 can suppress the generation of the eddy current RC flowing in the stretching direction in the blow molding die 13.

  The eddy current suppressing section 110 is constituted by high resistance sections 120A, 120B, 125A and 125B having a higher resistance than the metal material forming the blow molding die 13. The high-resistance portions 120A, 120B, 125A, and 125B are configured by, for example, disposing an insulator in the metal material of the blow molding die 13. The insulator only needs to have a higher resistance than the metal material, and is made of, for example, a material such as resin, ceramics, refractory, and FRP.

  As shown in FIG. 2, when viewed from the stretching direction D <b> 1, the upper mold 12 and the lower mold 11 of the blow molding mold 13 are divided into a plurality of (two in this example) divided by the high-resistance portions 120 </ b> A and 120 </ b> B. 130A and 130B, and base members 135A and 135B that support the plurality of divided members 130A and 130B.

  The upper and lower dies 12 and 11 are divided by the high-resistance portions 120A and 120B, respectively, at a central position in a horizontal direction D2 which is a horizontal direction perpendicular to the extending direction D1 of the metal pipe material 14. It is configured to be. In the present embodiment, the high-resistance portions 120A and 120B have a plate-like shape that extends straight in the up-down direction and the stretching direction D1. The high-resistance portions 120A and 120B extend vertically from the cavity-side ends of the upper mold 12 and the lower mold 11 to the base members 135A and 135B. The high-resistance portions 120A and 120B extend in the extending direction D1 from one end of the upper die 12 and the lower die 11 in the extending direction D1 to the other end.

  The base members 135A and 135B are provided on the side of the upper mold 12 and the lower mold 11 where the upper and lower holders 140A and 140B are attached. The holder 140A is a member that supports the upper die 12 from above, and the holder 140B is a member that supports the lower die 11 from below. The base members 135A and 135B are members integrally formed of a metal material. That is, the base members 135A and 135B are configured as one continuous plate-shaped member without being divided on the way by the high-resistance portions 120A and 120B and the high-resistance portions 125A and 125B described later. That is, the base members 135A and 135B extend from one end to the other end in the extending direction D1 of the upper mold 12 and the lower mold 11 (see FIG. 7), and extend from one end to the other end in the lateral direction D2. I have.

  Between the base members 135A and 135B and the plurality of divided members 130A and 130B, layers of high resistance parts 123A and 123B are provided. The high resistance portions 123A and 123B are formed corresponding to substantially the entire surfaces of the base members 135A and 135B. That is, the high resistance portions 123A and 123B extend from one end to the other end in the extending direction D1 of the upper mold 12 and the lower mold 11 (see FIG. 7), and extend from one end to the other end in the lateral direction D2. ing. However, the high resistance portions 123A and 123B may not be formed corresponding to substantially the entire surfaces of the base members 135A and 135B, and may be formed corresponding to only a part thereof. Further, the base members 135A, 135B and the high-resistance parts 123A, 123B are fixed to the division members 130A, 130B by screwing the screw part 150 into the division members 130A, 130B from the holders 140A, 140B side.

  As shown in FIG. 7, when viewed from the lateral direction D2, the upper die 12 and the lower die 11 of the blow molding die 13 are divided into a plurality of (two in this case) divided members 131A by the high-resistance portions 125A and 125B. , 131B, and base members 135A, 135B supporting the plurality of divided members 131A, 131B. Note that, for convenience of explanation, different reference numerals are used for the divided members 130A and 130B when viewed from the stretching direction D1 and for the divided members 131A and 131B when viewed from the lateral direction D2, but they are actually the same. Part.

  The dividing members 131A and 131B are configured by dividing the upper mold 12 and the lower mold 11 at high-resistance portions 125A and 125B, respectively, at the center position in the extending direction D1 of the metal pipe material 14. In the present embodiment, the high-resistance portions 125A and 125B have a plate-like shape that extends straight in the vertical direction and the horizontal direction D2. The high-resistance portions 125A and 125B extend vertically from the cavity-side ends of the upper mold 12 and the lower mold 11 to the base members 135A and 135B. The high-resistance portions 125A and 125B extend in the lateral direction D2 from one end of the upper mold 12 and the lower mold 11 in the lateral direction D2 to the other end. Note that high resistance portions 124A and 124B may be formed between the electrodes 17 and 18 at both ends of the upper mold 12 and the lower mold 11 in the extending direction D1.

  Next, the operation and effects of the molding apparatus according to the present embodiment will be described.

  When energizing and heating a metal pipe material with electrodes, energization may be performed rapidly in order to reduce the time required for the molding process. When the current change per unit time increases, the conventional molding apparatus has a problem that the eddy current generated in the molding die increases. When the eddy current increases, for example, the mold temperature rises, and heat is accumulated by repeating the energization in this state, and in some cases, the mold may not be quenched. Therefore, it is required to reduce the eddy current.

  According to the molding apparatus 10 according to the present embodiment, the pair of electrodes 17 and 18 conduct heat by energizing the metal pipe material 14, and the gas supply mechanism 40 supplies gas into the heated metal pipe material 14. As a result, the metal pipe 100 expands and comes into contact with the blow mold 13 to form the metal pipe 100. Here, when the pair of electrodes 17 and 18 conduct electricity to the metal pipe material 14, an eddy current RC (see FIG. 7) is generated in the blow molding die 13. However, since the blow molding die 13 has the eddy current suppressing portion 110 for suppressing the generation of the eddy current RC in the blow molding die 13, the generation of the eddy current RC in the blow molding die 13 is suppressed. You. As described above, the eddy current RC in the blow molding die 13 can be reduced.

  The pair of electrodes 17 and 18 are disposed at one end and the other end in the extending direction D1 of the metal pipe material 14 at the time of energization, respectively. The generation of eddy currents flowing through is suppressed. In this case, since the pair of electrodes 17 and 18 are arranged at one end and the other end in the extending direction D1 of the metal pipe 100, the eddy current RC easily occurs in the extending direction D1 in the blow molding die 13. Become. Therefore, the eddy current suppressor 110 suppresses the generation of the eddy current RC flowing in the blow molding die 13 in the stretching direction D1, so that the eddy current RC in the blow molding die 13 can be efficiently reduced. In the present embodiment, the high-resistance portions 125A and 125B that divide the upper mold 12 and the lower mold 11 in the stretching direction D1 can suppress generation of an eddy current RC flowing particularly in the stretching direction D1. The high-resistance portions 120A and 120B that divide the upper mold 12 and the lower mold 11 in the lateral direction D2 have less effect of directly reducing the eddy current RC than the high-resistance portions 125A and 125B. The effect of suppressing the spread of the lines of magnetic force within 13 is great.

  The eddy current suppressing section 110 is composed of high resistance sections 120A, 120B, 125A, and 125B having higher resistance than the metal material forming the blow molding die 13. In this case, the eddy currents RC are blocked by the high-resistance portions 120A, 120B, 125A, and 125B, so that the eddy currents RC are less likely to flow, and generation of the eddy currents RC can be suppressed. For example, in FIG. 7, when the high resistance portions 125A and 125B are not provided, in the upper mold 12 and the lower mold 11, the eddy current RC is damped from one end to the other end in the extending direction D1. A large flow can be formed without being performed. Therefore, the eddy current RC increases. On the other hand, since the high-resistance portions 125A and 125B dampen the eddy current RC, the eddy current RC forms a small flow within a limited range, so that the eddy current RC can be reduced.

  The molding apparatus 10 further includes holders 140A and 140B that support the blow molding die 13. The blow molding die 13 is provided on the mounting portion side of the plurality of divided members 130A, 131A, 130B, 131B divided by the high resistance parts 120A, 120B, 125A, 125B, and the holder 140A, 140B and the blow molding die 13. And base members 135A and 135B for supporting the plurality of divided members 130A, 131A, 130B and 131B. In this case, the plurality of divided members 130A, 131A, 130B, and 131B divided by the high-resistance parts 120A, 120B, 125A, and 125B are made of a metal material on the side where the holders 140A and 140B and the blow molding die 13 are attached. It is supported by base members 135A and 135B that are integrally formed. Therefore, the positional accuracy among the divided members 130A, 131A, 130B, 131B can be improved.

  The present invention is not limited to the above embodiment.

  In the above-described embodiment, the high-resistance portions 120A and 120B are exposed from the surfaces of the upper mold 12 and the lower mold 11 on the cavity side. Instead of this, for example, a configuration as shown in FIGS. 8 and 9 may be adopted. That is, as shown in FIGS. 8 and 9, the high resistance portions 120A, 120B, 125A, and 125B may be covered with a metal material on the cavity side of the upper mold 12 and the lower mold 11. As shown in FIG. 8, the cavity-side ends 120Aa and 120Ba of the high-resistance portions 120A and 120B are arranged inside the upper mold 12 and the lower mold 11, and the surfaces of the upper mold 12 and the lower mold 11 on the cavity side. Away from the inside. As shown in FIG. 9, the cavity-side ends 125Aa and 125Ba of the high-resistance portions 125A and 125B are arranged inside the upper mold 12 and the lower mold 11, and the surfaces of the upper mold 12 and the lower mold 11 on the cavity side. Away from the inside. In this case, since the portions where the high resistance portions 120A, 120B, 125A, and 125B are exposed are not provided on the cavity side of the blow molding die 13, no step is formed on the surface of the die. Accordingly, when the metal pipe 100 is formed by the blow molding die 13, the metal pipe 100 can be prevented from contacting the high-resistance portions 120A, 120B, 125A, and 125B, and the formability can be improved.

  Note that the configuration of the high-resistance portions 120A, 120B, 125A, and 125B is not limited to the configuration described above. For example, the positions and the number of the high resistance portions 120A and 120B in the horizontal direction D2 are not limited, and the angles with respect to the vertical direction and the stretching direction D1 may not be perpendicular. Further, as shown in FIG. 8, the high-resistance portions 120A and 120B may not only have the cavity-side end separated from the mold surface, but also have the opposite end separated from the base member. Further, the high-resistance portions 120A and 120B may be divided at an intermediate position in the vertical direction or the stretching direction D1. Similarly, the position and the number of the high resistance portions 125A and 125B in the stretching direction D1 are not limited, and the angles with respect to the vertical direction and the horizontal direction D2 do not have to be perpendicular. In addition, as shown in FIG. 9, not only the ends on the cavity side of the high-resistance portions 125A and 125B are separated from the mold surface, but also the ends on the opposite side may be separated from the base member. Further, the high-resistance portions 125A and 125B may be divided at an intermediate position in the vertical direction or the horizontal direction D2. It is sufficient that at least one of the high resistance portions 120A, 120B, 125A, and 125B is provided, and a part of the high resistance portions may be omitted.

  Further, in the above-described embodiment, the high resistance portion is formed using the insulator, but the high resistance portion may be formed by forming a gap. Even in this case, since the air has a higher resistance than the metal material, it functions as a high-resistance portion.

  Further, although the drive mechanism 80 according to the above embodiment moves only the upper mold 12, the lower mold 11 may move in addition to the upper mold 12 or instead of the upper mold 12. When the lower mold 11 moves, the lower mold 11 is not fixed to the base 15 and is attached to a slide of the drive mechanism 80.

  Further, the metal pipe according to the above embodiment may have a flange on one side thereof. In this case, the number of subcavities formed by the upper mold 12 and the lower mold 11 is one. Further, the metal pipe does not have to have the flange portion. In that case, no subcavity is provided.

  DESCRIPTION OF SYMBOLS 10 ... Molding apparatus, 11 ... Lower die, 12 ... Upper die, 13 ... Blow molding die (die), 14 ... Metal pipe material, 17, 18 ... Electrode, 40 ... Gas supply mechanism (Gas supply part), 100 ... metal pipe, 110 ... eddy current suppression part, 120A, 120B, 125A, 125B ... high resistance part, 130A, 130B, 131A, 131B ... division member, 135A, 135B ... base member.

Claims (4)

A molding device for expanding a metal pipe material to form a metal pipe,
At least one of which is movable, a molding die having a first die and a second die for molding the metal pipe;
A pair of electrodes for heating the metal pipe material by energizing the metal pipe material,
A gas supply unit for supplying a gas into the heated metal pipe material and expanding the gas supply material,
The molding die may have a suppressing eddy current suppressing section the generation of eddy current of the molding die in,
The eddy current suppressing portion is configured by a high resistance portion having a higher resistance than a metal material forming the molding die,
The molding device , wherein the high resistance portion is covered with the metal material on a cavity side of the molding die. A molding device for expanding a metal pipe material to form a metal pipe,
A molding die having at least one of which is movable and having a first die and a second die for molding the metal pipe;
A pair of electrodes for heating the metal pipe material by energizing the metal pipe material,
A gas supply unit for supplying a gas into the heated metal pipe material and expanding the gas;
A holder for supporting the molding die ,
The molding die may have a suppressing eddy current suppressing section the generation of eddy current of the molding die in,
The eddy current suppressing portion is configured by a high resistance portion having a higher resistance than a metal material forming the molding die,
The molding die,
A plurality of divided members divided by the high resistance portion,
A molding apparatus, comprising: a base member provided on a mounting portion side of the holder and the molding die and supporting the plurality of divided members . The pair of electrodes are arranged at one end and the other end in the direction in which the metal pipe material is stretched when energized,
The eddy current suppressing section suppresses the generation of eddy currents flowing in the stretching direction in the molding die during the molding apparatus according to claim 1 or 2. The molding device according to any one of claims 1 to 3, wherein the eddy current suppressing unit is configured by a high-resistance unit having a higher resistance than a metal material forming the molding die.

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