JP7101290B2 - Molding equipment - Google Patents

Description

The present invention relates to a molding apparatus.

Conventionally, a molding apparatus is known in which a metal pipe is closed by a mold and blow molded. For example, the molding apparatus disclosed in Patent Document 1 includes a mold and a gas supply unit for supplying gas into a metal pipe material. In this molding device, the inside of the metal pipe material is placed in the mold, and the metal pipe material is expanded by supplying gas from the gas supply unit to the metal pipe material with the mold closed. Mold into a shape corresponding to the shape. In this molding apparatus, the metal pipe material is held by the electrodes and the metal pipe material is energized and heated by the electrodes before the metal pipe material is expanded.

Japanese Unexamined Patent Publication No. 2012-000654

Here, in the above-mentioned molding apparatus, when the metal pipe material is energized and heated by the electrodes, the mold and the members around the mold may be magnetized. In such a case, during energization and heating of the metal pipe material, an electromagnetic force may act on the magnetized mold so that the mold moves in the slide direction, which is the direction in which the mold moves. When the mold moves due to the action of this electromagnetic force and comes into contact with the metal pipe material being energized and heated, electric leakage may occur through the mold and the device may be damaged.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a molding apparatus capable of improving safety.

The molding apparatus according to the present invention is a molding apparatus for expanding a metal pipe material to form a metal pipe, wherein at least one of them is movable and has an upper mold and a lower mold for forming the metal pipe. A pair of electrodes that heat the metal pipe material by energizing the metal pipe material, a power supply unit that supplies power to the pair of electrodes, and a gas supply that supplies gas into the heated metal pipe material to expand it. It is equipped with a department. The power supply unit is connected to a DC current generation unit that generates a DC current, a first power supply side line connected to the positive output end of the DC current generation unit, and a negative output end of the DC current generation unit. The second power supply side line, the first electrode side line connected to one of the pair of electrodes, and the second electrode side line connected to the other electrode of the pair of electrodes, and the operation. At that time, it is possible to electrically connect the first power supply side line and the first electrode side line and electrically connect the second power supply side line and the second electrode side line. When the electromagnetic switch 1 is operated, the first power supply side line and the second electrode side line are electrically connected, and the second power supply side line and the first electrode side line are electrically connected. It has a second electromagnetic switch that can be connected to the device, and a control unit that controls one of the first electromagnetic switch and the second electromagnetic switch to operate.

According to the molding apparatus according to the present invention, the direction of the direct current flowing through the metal pipe material can be switched by a simple configuration by switching the operation of the first electromagnetic switch and the second electromagnetic switch. Therefore, the magnetization of the mold can be reduced, and the movement of the mold due to the action of the electromagnetic force can be suppressed. This can improve safety.

The molding apparatus according to the present invention is a molding apparatus for expanding a metal pipe material to form a metal pipe, wherein at least one of them is movable and has an upper mold and a lower mold for forming the metal pipe. A pair of electrodes that heat the metal pipe material by energizing the metal pipe material, a power supply unit that supplies power to the electrodes, and a gas supply unit that supplies gas into the heated metal pipe material to expand it. , Equipped with. The power supply unit includes an AC power source that generates an AC current, a first electrode-side line connected to one of the pair of electrodes, and a second line connected to the other of the pair of electrodes. When an AC current is supplied to the electrode side line, it is converted to a DC current and output, and the positive output end is connected to the first electrode side line, and the negative output end is the second electrode side line. When an AC current is supplied to the first rectifier connected to, it is converted to a DC current and output, and the positive output end is connected to the second electrode side line, and the negative output end is the second. A second rectifier connected to the electrode side line of 1 and a first electromagnetic switch capable of electrically connecting an AC power supply and a first rectifier when operating, and when operating. , Control to operate either the second electromagnetic switch, the first electromagnetic switch or the second electromagnetic switch, which can electrically connect the AC power supply and the second rectifier. It has a control unit and a control unit for performing the above.

According to the molding apparatus according to the present invention, the direction of the direct current flowing through the metal pipe material can be switched by a simple configuration by switching the operation of the first electromagnetic switch and the second electromagnetic switch. Therefore, the magnetization of the mold can be reduced, and the movement of the mold due to the action of the electromagnetic force can be suppressed. This can improve safety.

As described above, according to the present invention, the safety of the molding apparatus can be improved.

It is a schematic block diagram which shows the molding apparatus which concerns on 1st Embodiment and 2nd Embodiment of this invention. It is a cross-sectional view of the blow molding die, the upper die, and the lower die holding part along the line II-II of FIG. It is an enlarged view of the periphery of the electrode, (a) is a view showing a state where the electrode holds a metal pipe material, (b) is a figure showing a state where a sealing member is in contact with the electrode, and (c) is a view showing a state where a sealing member is in contact with the electrode, and (c) is a front view of the electrode. It is a figure. It is a figure which shows the manufacturing process by a molding apparatus, (a) is a figure which shows the state which the metal pipe material is set in the mold, (b) is the figure which shows the state which the metal pipe material is held by the electrode. be. It is a figure which shows the manufacturing process following FIG. It is a figure which shows the operation of the blow molding die and the upper die holder, and the change of the shape of a metal pipe material. It is a figure following FIG. It is a figure following FIG. It is a schematic block diagram which shows the electric power supply part of the molding apparatus which concerns on 1st Embodiment of this invention. It is a schematic block diagram which shows the electric power supply part of the molding apparatus which concerns on 2nd Embodiment of this invention.

Hereinafter, a preferred embodiment 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.

[First Embodiment]
<Structure of molding equipment>
FIG. 1 is a schematic configuration diagram of a molding apparatus, and FIG. 2 is a cross-sectional view of a blow molding die, an upper die, and a lower die holding portion along the line II-II of FIG. As shown in FIG. 1, the molding apparatus 10 for molding the metal pipe 100 (see FIG. 5) holds a blow molding mold 13 composed of a lower mold 11 and an upper mold 12 paired with each other, and a lower mold 11. At least one of the upper mold holding portion 91 for holding the lower mold holding portion 91 and the upper mold 12 for the purpose, and the upper mold holding portion 92 for holding the lower mold holding portion 91 and the upper mold 12 for holding the lower mold 11. Here, the drive mechanism 80 for moving the upper mold holding portion 92), the pipe holding mechanism 30 for holding the metal pipe material 14 shown by a virtual line between the lower mold 11 and the upper mold 12, and the pipe holding mechanism 30. A heating mechanism 50 that energizes and heats the held metal pipe material 14, and a high-pressure gas (gas) for supplying high-pressure gas (gas) into the metal pipe material 14 held and heated between the lower mold 11 and the upper mold 12. A gas supply unit 60, a pair of gas supply mechanisms (gas supply units) 40, 40 for supplying gas from the gas supply unit 60 into the metal pipe material 14 held by the pipe holding mechanism 30, and a blow molding metal. A water circulation mechanism 72 for forcibly cooling the mold 13 with water is provided. The molding device 10 according to the present embodiment includes a lower mold drive mechanism 90 that drives the lower mold 11 up and down. Further, the molding device 10 controls the drive of the drive mechanism 80, the drive of the lower drive mechanism 90, the drive of the pipe holding mechanism 30, the drive of the heating mechanism 50, and the gas supply of the gas supply unit 60, respectively. It is configured to include a control unit 70.

The lower mold 11 is fixed to a large base 15 via a lower mold holding portion 91. The lower mold 11 is composed of a large steel block, and has a recess 16 on the upper surface thereof (partitioning surface from the upper mold 12). As shown in FIGS. 1 and 2, the lower die holding portion 91 for holding the lower die 11 holds the first lower die holder 93 and the first lower die holder 93 for holding the lower die 11 in this order from the top. The lower die base plate 95 for holding the second lower die holder 94 and the second lower die holder 94 is provided in an overlapping manner, and the lower die base plate 95 is fixed to the base 15. Then, as shown in FIG. 1, the axial length of the first lower die holder 93 and the second lower die holder 94 (horizontal length in FIG. 1) is almost the same as the axial length of the lower die 11. It has become.

Further, an electrode storage space 11a is provided near the left and right ends (left and right ends in FIG. 1) of the lower mold 11, and a pair configured to be able to move up and down in the electrode storage space 11a by an actuator (not shown). (1st electrode 17 and 2nd electrode 18) are provided. Semi-arc-shaped concave grooves 17a and 18a corresponding to the lower outer peripheral surface of the metal pipe material 14 are formed on the upper surfaces of the first electrode 17 and the second electrode 18 (see FIG. 3C). The metal pipe material 14 can be placed so as to fit into the portions of the concave grooves 17a and 18a.
Further, on the front surface (the surface in the outer direction of the mold) of the first and second electrodes 17 and 18, tapered concave surfaces 17b and 18b are formed in which the periphery is inclined in a tapered shape toward the concave grooves 17a and 18a. There is. Further, a cooling water passage 19 is formed in the lower mold 11. On the lower surface side of the lower die 11, a lower die drive mechanism 90 that penetrates the second lower die holder 94 and the lower die base plate 95 and extends in the vertical direction is provided. The lower mold drive mechanism 90 includes a support portion 101 that supports the lower surface of the lower mold 11, and a shaft portion 102 that extends downward from the support portion 101. The lower end side of the shaft portion 102 is connected to a drive portion (not shown).

The pair of first and second electrodes 17 and 18 located on the lower mold 11 side constitutes a pipe holding mechanism 30, and the metal pipe material 14 can be raised and lowered between the upper mold 12 and the lower mold 11. Can be supported by. The molding apparatus 10 is provided with a thermocouple (not shown) for measuring the temperature of the metal pipe material 14. For example, the thermocouple may be inserted from the side of the mold 13. However, the thermocouple is only an example of the temperature measuring means, and may be a non-contact temperature sensor such as a radiation thermometer or an optical thermometer. If the correlation between the energization time and the temperature is obtained, it is possible to omit the temperature measuring means.

The upper mold 12 is a large steel block having a recess 24 on the lower surface thereof (partitioning surface from the lower mold 11) and having a cooling water passage 25 built therein. As shown in FIGS. 1 and 2, the upper die holding portion 92 that holds the upper die 12 holds the first upper die holder 96 and the first upper die holder 96 that hold the upper die 12 in this order from the bottom. The upper die base plate 98 for holding the second upper die holder 97 and the second upper die holder 97 is stacked and provided, and the upper die base plate 98 is fixed to the slide 82. Then, as shown in FIG. 1, the axial length of the first upper die holder 96 and the second upper die holder 97 (horizontal length in FIG. 1) is almost the same as the axial length of the upper die 12. It has become. Further, the slide 82 to which the upper mold holding portion 92 is fixed is suspended by the pressure cylinder 26, and is guided by the guide cylinder 27 so as not to swing sideways.

An electrode storage space 12a similar to that of the lower mold 11 is provided in the vicinity of the left and right ends (left and right ends in FIG. 1) of the upper mold 12, and an actuator (not shown) is provided in the electrode storage space 12a as in the lower mold 11. ), The first electrode 17 and the second electrode 18 configured to be able to move up and down are provided. Semi-circular concave grooves 17a and 18a corresponding to the upper outer peripheral surface of the metal pipe material 14 are formed on the lower surfaces of the first and second electrodes 17 and 18 (see FIG. 3C). The metal pipe material 14 can be fitted into the concave grooves 17a and 18a. Further, on the front surface (the surface in the outer direction of the mold) of the first and second electrodes 17 and 18, tapered concave surfaces 17b and 18b are formed in which the periphery is inclined in a tapered shape toward the concave grooves 17a and 18a. There is. Therefore, the pair of first and second electrodes 17 and 18 located on the upper mold 12 side also constitutes the pipe holding mechanism 30, and the metal pipe material 14 is moved up and down by the pair of upper and lower first and second electrodes 17 and 18. When sandwiched from the direction, it is configured so that the outer periphery of the metal pipe material 14 can be surrounded so as to be in close contact with the entire circumference. The fixing portion of each actuator that moves the first electrode 17 and the second electrode 18 which are movable portions up and down is held and fixed to the lower mold holding portion 91 and the upper mold holding portion 92, respectively.

The drive mechanism 80 includes a slide 82 that moves the upper mold 12 and the upper mold holding portion 92 so that the upper mold 12 and the lower mold 11 meet each other, and a drive unit 81 that generates a driving force for moving the slide 82. A servomotor 83 that controls the amount of fluid with respect to the drive unit 81 is provided. The drive unit 81 is composed of a fluid supply unit that supplies a fluid for driving the pressure cylinder 26 (operating oil when a hydraulic cylinder is used as the pressure cylinder 26) to the pressure 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 drive unit 81 is not limited to the one that applies a driving force to the slide 82 via the pressurizing cylinder 26 as described above. For example, the drive unit is mechanically connected to the slide 82 to generate a servomotor 83. The driving force to be applied may be directly or indirectly applied to the slide 82. For example, the eccentric shaft, a drive source that applies a rotational force to rotate the eccentric shaft (for example, a servo motor and a speed reducer, etc.), and a conversion unit that converts the rotational movement of the eccentric shaft into a linear motion to move the slide (for example,). , A connecting rod, an eccentric sleeve, etc.), and a drive mechanism having the same may be adopted. In this embodiment, the drive unit 81 does not have to include the servomotor 83.

As shown in FIG. 2, a step is provided on both the upper end surface of the lower mold 11 and the lower end surface of the upper mold 12. Specifically, a concave portion 16 having a rectangular cross section is formed in the center of the upper end surface of the lower mold 11, and a cross section is formed at a position facing the concave portion 16 of the lower mold 11 in the center of the lower end surface of the upper mold 12. A rectangular recess 24 is formed.

The first lower die holder 93 that constitutes the lower mold holding portion 91 and holds the lower mold 11 is provided with a recess 93a having a rectangular cross section in the center of the upper end surface 93e of the rectangular cuboid, and the bottom surface 93d of the recess 93a is provided. The substantially lower half of the lower die 11 is fitted and held in the gap 93c provided in the center and dividing the first lower die holder 93. Between the convex portions 93b and 93b on both sides forming the concave portion 93a of the first lower die holder 93 and the side surface of the substantially upper half of the lower die 11 projecting upward from the bottom surface 93d of the first lower die holder 93. Spaces S1 and S2 are provided, respectively, and the spaces S1 and S2 are spaces into which the convex portion 96b described later of the first upper die holder 96 enters when the blow molding die 13 is closed.

The first upper die holder 96 that constitutes the upper die holding portion 92 and holds the upper die 12 is a rectangular cuboid that faces downward by forming two stepped steps from the upper side to the lower side on both sides of the rectangular cuboid. Is configured in a stepped block shape in which is gradually reduced. A recess 96a having a rectangular cross section is formed in the center of the lower end surface 96d of the first upper die holder 96, and the upper die 12 is accommodated and held in the recess 96a. Therefore, the inner side surfaces of the convex portions 96b and 96b on both sides forming the concave portion 96a of the first upper die holder 96 are in contact with the side surface of the upper mold 12. Further, the convex portions 96b and 96b are portions that protrude downward from the lower end surface of the upper die 12 by a predetermined length and enter the spaces S1 and S2 of the first lower die holder 93 when the blow molding die 13 is closed. It has become. Further, when the blow molding die 13 is closed, the lower end surface (tip surface) 96d of the convex portion 96b of the first upper die holder 96 comes into contact with the bottom surface 93d of the concave portion 93a of the first lower die holder 93. The stepped surface 96e formed on both sides of the convex portion 96b of the first upper die holder 96 and located above the convex portion 96b hits the upper end surface 93e of the convex portion 93b of the first lower die holder 93. It is designed to come into contact.

As shown in FIG. 1, the heating mechanism 50 includes a first electrode 17, a second electrode 18, a power source 51, and a conducting wire extending from the power source 51 and connected to the first electrode 17 and the second electrode 18, respectively. It has a 52 and a switch 53 interposed in the lead wire 52. By controlling the heating mechanism 50, the control unit 70 can heat the metal pipe material 14 to the quenching temperature (AC3 transformation point temperature or higher).

Each of the pair of gas supply mechanisms 40 includes a cylinder unit 42, a cylinder rod 43 that moves forward and backward according to the operation of the cylinder unit 42, and a seal member 44 connected to the tip of the cylinder rod 43 on the pipe holding mechanism 30 side. , Have. The cylinder unit 42 is placed and fixed on the base 15 via 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 have a shape that can be fitted and contacted with the tapered concave surfaces 17b and 18b of the first and second electrodes 17 and 18. (See Fig. 3).
The seal member 44 extends from the cylinder unit 42 side toward the tip, and as shown in FIGS. 3 (a) and 3 (b), a gas passage through which the high-pressure gas supplied from the gas supply unit 60 flows. 46 is provided.

As shown in FIG. 1, the gas supply unit 60 extends from the high pressure gas source 61, the accumulator 62 for storing the gas supplied by the high pressure gas source 61, and the cylinder unit 42 of the gas supply mechanism 40. The first tube 63, the pressure control valve 64 and the switching valve 65 interposed in the first tube 63, and the second tube extending from the accumulator 62 to the gas passage 46 formed in the seal member 44. The 67 is composed of a pressure control valve 68 and a check valve 69 interposed in the second tube 67. 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 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 a thermocouple (not shown) and controls the pressure cylinder 26, the switch 53, 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.

<Molding method of metal pipe using molding equipment>
Next, a method of forming a metal pipe using the forming apparatus 10 will be described. FIG. 4 shows from a pipe charging step of charging the metal pipe material 14 as a material to an energization heating step of energizing and heating the metal pipe material 14. More specifically, FIG. 4A is a diagram showing a state in which the metal pipe material is set in the mold, and FIG. 4B is a diagram showing a state in which the metal pipe material is held by the electrodes. Further, FIG. 5 is a diagram showing a manufacturing process following FIG.

First, a metal pipe material 14 of a steel grade that can be hardened 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 side by using, for example, a robot arm or the like. Since the concave grooves 17a and 18a are formed in the first and second electrodes 17 and 18, 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. 4B, 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 located above and below each are operated. , 18 are brought close to each other and brought into contact with each other. 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. Further, this sandwiching is sandwiched in such a manner that the recessed grooves 17a and 18a formed in the first and second electrodes 17 and 18 are in close contact with each other over the entire circumference of the metal pipe material 14. ..

Subsequently, as shown in FIG. 1, the control unit 70 heats the metal pipe material 14 by controlling the heating mechanism 50. Specifically, the control unit 70 turns on the switch 53 of the heating mechanism 50. Then, power is supplied from the power source 51 to the metal pipe material 14, and the metal pipe material 14 itself generates heat due to the resistance existing in the metal pipe material 14 (Joule heat). At this time, the measured value of the thermocouple is constantly monitored, the energization is controlled based on this result, and the cylinder unit 42 of the gas supply mechanism 40 is operated to seal both ends of the metal pipe material 14 with the sealing member 44. (See also FIG. 3).

FIG. 6 is a diagram showing the operation of the blow molding die and the first upper die holder and the change in the shape of the metal pipe material, FIG. 7 is a diagram following FIG. 6, and FIG. 8 is a diagram following FIG. 7.

As shown in FIG. 6, the blow molding die 13 is closed with respect to the heated metal pipe material 14. At this time, the convex portions 96b and 96b of the first upper die holder 96 enter the spaces S1 and S2 of the first lower die holder 93, and a pipe is formed between the concave portion 16 of the lower mold 11 and the concave portion 24 of the upper mold 12. A main cavity MC having a substantially rectangular cross section, which is a gap for forming the portion (main body portion) 100a, is formed, and the main cavity MC is formed between the upper end surface of the lower mold 11 and the lower end surface of the upper mold 12. Sub-cavity portions SC1 and SC2, which are gaps for forming flange portions 100b and 100c, are formed on both sides of the main cavity portion MC, respectively.

Here, the subcavities SC1 and SC2 between the upper end surface of the lower mold 11 and the lower end surface of the upper mold 12 extend so as to be open to the outside of the mold, while the subcavities SC1 and SC2 are , The inner side surfaces 96f of the convex portions 96b and 96b of the first upper die holder 96 are closed from the outside. In the convex portions 96b and 96b that close the sub-cavities SC1 and SC2 of the first upper die holder 96 from outside the mold, foreign matter such as debris generated when a metal pipe ruptures in the mold can be removed from the sub-cavities SC1 and SC2. It works to block the progress to the outside of the mold and prevent it from being released. Therefore, the first upper die holder 96 having the convex portions 96b and 96b also functions as a shield member.

Then, in this state, that is, before the blow molding die is completely closed, the metal pipe material 14 fits in the main cavity portion MC, and generally, the bottom surface of the recess 16 of the lower die 11 and the upper die 12 From the state of being in contact with the bottom surface of the recess 24, high-pressure gas is supplied into the metal pipe material 14 by the gas supply unit 60, and blow molding is started.

Here, 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.

In parallel with this, the blow molding die 13 is further closed, and as shown in FIG. 7, the main cavity portion MC and the sub-cavity portions SC1 and SC2 are further formed between the lower mold 11 and the upper mold 12. It will be narrowed down.

Therefore, the metal pipe material 14 expands in the main cavity portion MC so as to follow the recesses 16 and 24, and a part (both sides) 14a and 14b of the metal pipe material 14 are placed in the subcavity portions SC1 and SC2. It expands so that it can enter each.

Then, as shown in FIG. 8, the blow molding die 13 is further closed, and the lower end surface of the convex portion 96b of the first upper die holder 96 is formed on the bottom surface 93d of the concave portion 93a of the first lower die holder 93. The 96d abuts, the stepped surface 96e of the first upper die holder 96 abuts on the upper end surface 93e of the convex portion 93b of the first lower die holder 93, and the inside of the convex portion 93b of the first lower die holder 93. The mold closing of the blow molding die 13 is completed in a state where the side surface and the outer surface of the convex portion 96b of the first upper die holder 96 are in contact with each other and the first lower die holder 93 and the first upper die holder 96 are in close contact with each other.

At this time, the main cavity portions MC and the sub-cavity portions SC1 and SC2 are in a state of being further narrowed from the state shown in FIG. 7, and in this state, as described above, the sub-cavity portions SC1 and SC2 are in the first state. The convex portions 96b and 96b of the upper die holder 96 are closed from the outside by the inner side surfaces 96f.

Therefore, the metal pipe material 14 softened by heating and supplied with the high-pressure gas is formed in the main cavity MC as a pipe portion 100a having a rectangular cross section that matches the rectangular cross section of the main cavity MC, and is also a sub. In the cavities SC1 and SC2, a part of the metal pipe material 14 is formed as folded flange portions 100b and 100c.

At the time of this blow molding, the outer peripheral surface of the metal pipe material 14 blow-molded and expanded comes into contact with the recess 16 of the lower mold 11 and is rapidly cooled, and at the same time, it is contacted with the recess 24 of the upper mold 12 and rapidly cooled ( Since the upper mold 12 and the lower mold 11 have a large heat capacity and are controlled at a low temperature, if the metal pipe material 14 comes into contact with the metal pipe material 14, the heat on the pipe surface is taken away to the mold side at once) and quenching is performed. .. Such a cooling method is called mold contact cooling or mold cooling. Immediately after being quenched, austenite transforms 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 tissue (troostite, sorbite, etc.) due to 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 to the metal pipe 100 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. It should be noted that the description in this paragraph has been described by taking the case where the metal pipe material 14 is steel as an example.

Then, as shown in FIG. 5, the metal pipe 100 having the pipe portion 100a and the flange portions 100b and 100c can be obtained as a molded product by the molding method as described above. In the present embodiment, since the main cavity portion MC is configured to have a rectangular cross section, the metal pipe material 14 is blow-molded according to the shape, so that the pipe portion 100a is formed into a rectangular tubular shape. .. However, the shape of the main cavity MC is not particularly limited, and any shape such as a circular cross section, an elliptical cross section, and a polygonal cross section may be adopted according to the desired shape.

<Structure of power supply unit>
The molding apparatus 10 according to the present embodiment includes a power supply unit 120 that supplies electric power to the first electrode 17 and the second electrode 18. Hereinafter, the configuration of the power supply unit 120 and its surroundings according to the present embodiment will be described with reference to FIG. 9.

The power supply unit 120 shown in FIG. 9 is incorporated in a molding apparatus 10 as shown in FIG. 1 and supplies power to a pair of electrodes (first electrode 17 and second electrode 18). As a result, the metal pipe material 14 is energized and heated. At this time, the mold 13 and the members around the mold may be magnetized. For example, if the energization heating is continued for a certain period of time with the first electrode 17 of one of the pair of electrodes as the positive electrode and the second electrode 18 of the other of the pair of electrodes as the negative electrode, the mold 13 is predetermined. Magnetization progresses in the direction of. In such a case, during the energization heating of the metal pipe material 14, an electromagnetic force that causes the mold 13 to move in the slide direction, which is the direction in which the mold 13 moves, may act on the magnetized mold 13. There is sex. When the mold 13 moves due to the action of this electromagnetic force and comes into contact with the metal pipe material 14 being energized and heated, electric leakage may occur through the mold 13 and the device may be damaged. Therefore, the power supply unit 120 of the molding apparatus 10 according to the present embodiment supplies the electric power supply unit 120 to the first electrode 17 and the second electrode 18 in order to reduce the magnetization of the mold 13 and suppress the movement of the mold 13 due to the electromagnetic force. It is provided with a switching unit 125 capable of switching the direction of the DC current.

Next, a specific configuration of the power supply unit 120 will be described.

As shown in FIG. 9, the power supply unit 120 is connected to an alternating current power supply 121 for generating an alternating current, an inverter 122, a transformer 123 as a rectifier, and a first output terminal 123P on the positive side of the transformer 123. Connected to the power supply side line 143a, the second power supply side line 143b connected to the negative output end 123N of the transformer 123, the first electrode side line 145a connected to the first electrode 17, and the second electrode 18. The second electrode side line 145b and the first power supply side line 143a and the second power supply side line 143b are electrically connected and connected to the first electrode side line 145a and the second electrode side line 145b. A switching unit 125 capable of switching the state and a control unit 126 for controlling the switching of the switching unit 125 are provided. Here, a bus bar may be used for the first power supply side line 143a, the second power supply side line 143b, the first electrode side line 145a, and the second electrode side line 145b, but the bus bar is not particularly limited.

The AC power supply 121 generates three-phase AC and is connected to the inverter 122 by three cables. Specifically, the U phase is transmitted to the inverter 122 by the cable 141a, the V phase is transmitted by the cable 141b, and the W phase is transmitted by the cable 141c. As the AC power supply 121, for example, 3ΦAC200V or 3ΦAC400V is used, but is not particularly limited.

The inverter 122 is connected to the transformer 123 as a rectifier by two cables. Specifically, the U phase is transmitted to the transformer 123 by the cable 142a and the V phase is transmitted by the cable 142b. Here, the output from the inverter 122 is, for example, single-phase AC300V800A and single-phase AC600V800A, but is not particularly limited.

As described above, the transformer 123 is connected to the switching unit 125 by the first power supply side line 143a and the second power supply side line 143b. Specifically, the positive output end 123P of the transformer 123 is connected to the terminal 125a of the switching unit 125 by the first power supply side line 143a, and the negative output end 123N is connected to the switching unit 125 by the second power supply side line 143b. It is connected to the terminal 125b. When an alternating current is supplied, the transformer 123 converts it into a direct current and outputs it. Therefore, the AC power supply 121, the inverter 122, and the transformer 123 may be collectively regarded as a DC current generating unit that generates a DC current. Here, the output from the transformer 123 is, for example, DC20V15000A and DC30V10000A, but is not particularly limited.

As described above, the switching unit 125 is connected to the first electrode 17 and the second electrode 18 of the pipe holding mechanism 30 by the first electrode side line 145a and the second electrode side line 145b. Specifically, the output from the terminal 125c of the switching unit 125 is connected to the first electrode 17 by the first electrode side line 145a, and the output from the terminal 125d of the switching unit 125 is connected to the second electrode side line 145b. It is connected to the second electrode 18.

Further, the switching unit 125 has an electromagnetic switch MC1 (first electromagnetic switch) and an electromagnetic switch MC2 (second electromagnetic switch). When the electromagnetic switch MC1 operates (when it is ON), the first power supply side line 143a and the first electrode side line 145a are electrically connected, and the second power supply side line 143b and the second power supply side line 143b are connected. It is possible to electrically connect to the electrode side line 145b. Further, when the electromagnetic switch MC2 operates (when it is ON), the first power supply side line 143a and the second electrode side line 145b are electrically connected, and the second power supply side line 143b and the first power supply side line 143b are connected. It is possible to electrically connect to the electrode side line 145a of the above. The specific internal structure of the switching unit 125 is as follows.

The terminal 125a of the switching unit 125 is connected to the terminal MC1a of the electromagnetic switch MC1 and the terminal MC2a of the electromagnetic switch MC2 by the internal cable of the switching unit 125 that branches at the branch point A. Specifically, the cable 125e1 connected to the terminal 125a is branched into the cables 125e2 and 125e3 at the branch point A. The cable 125e2 is connected to the terminal MC1a of the electromagnetic switch MC1. The cable 125e3 is connected to the terminal MC2a of the electromagnetic switch MC2. The terminal 125b is connected to the terminal MC1b of the electromagnetic switch MC1 and the terminal MC2b of the electromagnetic switch MC2 by the internal cable of the switching portion 125 branched at the branch point B. Specifically, the cable 125f1 connected to the terminal 125b is branched into the cables 125f2 and 125f3 at the branch point A. The cable 125f2 is connected to the terminal MC1b of the electromagnetic switch MC1. The cable 125f3 is connected to the terminal MC2b of the electromagnetic switch MC2.

Further, the terminal MC1c of the electromagnetic switch MC1 and the terminal MC2d of the electromagnetic switch MC2 are connected to the terminal 125c by an internal cable branched at the branch point C. Specifically, the cable 125g1 connected to the terminal MC1c of the electromagnetic switch MC1 and the cable 125g2 connected to the terminal MC2d of the electromagnetic switch MC2 are integrated into the cable 125g3 at the branch point C. The cable 125g3 is connected to the terminal 125c. The terminal MC1d of the electromagnetic switch MC1 and the terminal MC2c of the electromagnetic switch MC2 are connected to the terminal 125d by an internal cable branched at the branch point D. Specifically, the cable 125h1 connected to the terminal MC1d of the electromagnetic switch MC1 and the cable 125h2 connected to the terminal MC2c of the electromagnetic switch MC2 are integrated into the cable 125h3 at the branch point D. The cable 125h3 is connected to the terminal 125d.

With the above configuration, the electromagnetic switch MC1 electrically connects the positive output end 123P of the transformer 123 and the first electrode 17, and electrically connects the negative output end 123N of the transformer 123 and the second electrode 18. It is possible to connect to. The electromagnetic switch MC2 can electrically connect the positive output end 123P of the transformer 123 and the second electrode 18, and also electrically connect the negative output end 123N of the transformer 123 and the first electrode 17. It is possible. That is, the switching unit 125 is in an electrically connected state between the positive output end 123P and the negative output end 123N of the transformer 123 and the first electrode 17 and the second electrode 18 by the electromagnetic switch MC1 and the electromagnetic switch MC2. Can be switched.

The control unit 126 controls so that either the electromagnetic switch MC1 or the electromagnetic switch MC2 operates. Specifically, the control unit 126 turns off the electromagnetic switch MC2 when the electromagnetic switch MC1 is ON, and turns off the electromagnetic switch MC1 when the electromagnetic switch MC2 is ON. Control is performed so as to be. As a result, the control unit 126 electrically connects the positive output end 123P of the transformer 123 and the first electrode 17, and also electrically connects the negative output end 123N of the transformer 123 and the second electrode 18. 1 and the second state in which the positive output end 123P of the transformer 123 and the second electrode 18 are electrically connected and the negative output end 123N of the transformer 123 and the first electrode 17 are electrically connected. To switch between. In the first state, the first electrode becomes a positive electrode and the second electrode becomes a negative electrode. In the second state, the first electrode becomes a negative electrode and the second electrode becomes a positive electrode. Therefore, the control unit 126 causes the switching unit 125 to switch between the first state and the second state at predetermined intervals, so that the direction of the direct current flowing through the metal pipe material is also switched at predetermined intervals.

With the above configuration, the direction of the direct current flowing through the metal pipe material can be switched by a simple configuration by switching the operation of the electromagnetic switch MC1 and the electromagnetic switch MC2. Since the magnetization in the mold 13 in a predetermined direction can be canceled, the magnetization of the mold 13 can be reduced and the movement of the mold due to the action of the electromagnetic force can be suppressed. The control unit 126 may cause the switching unit 125 to switch a plurality of times during the energization heating, may switch each time the energization heating is performed, or may cause the switching unit 125 to perform the switching each time the energization heating is performed a plurality of times. May be switched to.

Further, since the electromagnetic switch MC1 and the electromagnetic switch MC2 are controlled by the control unit 126, the magnetization of the mold 13 can be reduced and the action of the electromagnetic force can be reduced by a simple configuration that can be performed by using a commercially available device. It is possible to suppress the movement of the mold due to.

[Second Embodiment]
In the second embodiment of the present invention, the molding apparatus 10 employs the power supply unit 130 as shown in FIG. 10 instead of the power supply unit 120 shown in the first embodiment. The switching unit 135 in the power supply unit 130 has two transformers 133A and 133B (a first rectifier and a second rectifier). The control unit 136 switches the transformer to be energized by switching the connection state to the switching unit 135, and switches the direction of the direct current flowing through the metal pipe material. Hereinafter, the configuration of the power supply unit 130 and its surroundings according to the present embodiment will be specifically described with reference to FIG. 10. The parts that overlap with those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 10, the power supply unit 130 includes an alternating current power supply 121 for generating an alternating current, an inverter 122, and a first power supply side line 152a and a second power supply side line 152b connected to the inverter 122. , The first electrode side line 145a connected to the first electrode 17, the second electrode side line 145b connected to the second electrode 18, the first power supply side line 152a, and the second power supply side line 152b. Is provided with a switching unit 135 capable of electrically connecting to the first electrode side line 145a and the second electrode side line 145b and switching the connection state, and a control unit 136 for controlling the switching of the switching unit 135. There is. Here, a cable is used for the first power supply side line 152a and the second power supply side line 152b. Further, a bus bar is used for the first electrode side line 145a and the second electrode side line 145b. However, the configuration of each line is not particularly limited. The AC power supply 121 and the inverter 122 have the same configuration as the power supply unit 120 of the first embodiment. Further, the connection between the AC power supply 121 and the inverter 122 has the same configuration as that of the power supply unit 120 of the first embodiment.

As described above, the inverter 122 is connected to the switching unit 135 by the first power supply side line 152a and the second power supply side line 152b. The U phase is transmitted to the terminal 135a of the switching unit 135 by the first power supply side line 152a, and the V phase is transmitted to the terminal 135b of the switching unit 135 by the second power supply side line 152b.

As described above, the switching unit 135 includes a transformer 133A as a first rectifier and a transformer 133B as a second rectifier. When an alternating current is supplied, the transformer 133A and the transformer 133B convert the current into a direct current and output the current. In the transformer 133A, the positive output end 133AP is connected to the first electrode side line 145a, and the negative output end 133AN is connected to the second electrode side line 145b. Further, in the transformer 133B, the positive output end 133BP is connected to the second electrode side line 145b, and the negative output end 133BN is connected to the first electrode side line 145a.

Further, the switching unit 135 includes an electromagnetic switch MC3 (first electromagnetic switch) and an electromagnetic switch MC4 (second electromagnetic switch). When the electromagnetic switch MC3 operates (when it is ON), the first power supply side line 152a and the second power supply side line 152b can be electrically connected to the transformer 133A as the first rectifier. be. That is, the electromagnetic switch MC3 can electrically connect the AC power supply 121 and the first rectifier when it operates. Further, when the electromagnetic switch MC4 operates (when it is ON), the first power supply side line 152a and the second power supply side line 152b may be electrically connected to the transformer 133B as the second rectifier. It is possible. That is, the electromagnetic switch MC4 can electrically connect the AC power supply 121 and the second rectifier when it operates. The specific internal structure of the switching unit 135 is as follows.

The terminal 135a of the switching unit 135 is connected to the terminal MC3a of the electromagnetic switch MC3 and the terminal MC4a of the electromagnetic switch MC4 by the internal cable of the switching unit 135 that branches at the branch point E. Specifically, the cable 135e1 connected to the terminal 135a is branched into the cables 135e2 and 135e3 at the branch point E. The cable 135e2 is connected to the terminal MC3a of the electromagnetic switch MC3. The cable 135e3 is connected to the terminal MC4a of the electromagnetic switch MC4. The terminal 135b is connected to the terminal MC3b of the electromagnetic switch MC3 and the terminal MC4b of the electromagnetic switch MC4 by an internal cable of the switching portion 135 that branches at the branch point F. Specifically, the cable 135f1 connected to the terminal 135b is branched into the cables 135f2 and 135f3 at the branch point F. The cable 135f2 is connected to the terminal MC3b of the electromagnetic switch MC3. The cable 135f3 is connected to the terminal MC4b of the electromagnetic switch MC4. The terminal MC3c and the terminal MC3d of the electromagnetic switch MC3 are connected to the transformer 133A as a rectifier by the cables 135e4 and 135f4 inside the switching unit 135. The terminal MC4c and the terminal MC4d of the electromagnetic switch MC4 are connected to the transformer 133B as a rectifier by the cables 135e5 and 135f5 inside the switching unit 135.

The positive output end 133AP of the transformer 133A and the negative output end 133BN of the transformer 133B are connected to the terminal 135c by an internal cable branched at the branch point G. Specifically, the cable 135g1 connected to the positive output end 133AP of the transformer 133A and the cable 135g2 connected to the negative output end 133BN of the transformer 133B are integrated into the cable 135g3 at the branch point G. There is. The cable 135g3 is connected to the terminal 135c. The negative output end 133AN of the transformer 133A and the positive output end 133BP of the transformer 133B are connected to the terminal 135d by an internal cable branched at the branch point H. Specifically, the cable 135h1 connected to the negative output end 133AN of the transformer 133A and the cable 135h2 connected to the positive output end 133BP of the transformer 133B are integrated into the cable 135h3 at the branch point H. There is. The cable 135h3 is connected to the terminal 135d. Therefore, in the transformer 133A, the positive output end 133AP is connected to the first electrode 17, and the negative output end 133AN is connected to the second electrode 18. Further, in the transformer 133B, the positive output end 133BP is connected to the second electrode 18, and the negative output end 133BN is connected to the first electrode 17.

With the above configuration, the electromagnetic switch MC3 can electrically connect the AC power supply 121 and the transformer 133A as a rectifier. The electromagnetic switch MC4 can electrically connect the AC power supply 121 and the transformer 133B as a rectifier. That is, the switching unit 135 can switch the electrical connection state of the AC power supply to the transformer 133A and the transformer 133B by the electromagnetic switch MC3 and the electromagnetic switch MC4. In other words, the switching unit 135 uses the electromagnetic switch MC3 and the electromagnetic switch MC4 to provide the positive output ends 133AP and 133BP of the transformer 133A and the transformer 133B, the negative output ends 133AN and 133BN, and the first electrode 17 and the second electrode. The state of electrical connection with the electrode 18 can be switched.

The control unit 136 controls so that either the electromagnetic switch MC3 or the electromagnetic switch MC4 operates. Specifically, the control unit 136 turns off the electromagnetic switch MC4 when the electromagnetic switch MC3 is ON, and turns off the electromagnetic switch MC3 when the electromagnetic switch MC4 is ON. Control is performed so as to be. As a result, the control unit 136 switches between a third state in which the AC power supply 121 and the transformer 133A are electrically connected and a fourth state in which the AC power supply 121 and the transformer 133B are electrically connected. In the third state, a voltage is applied from the transformer 133A to the first electrode 17 and the second electrode 18.
Therefore, in the third state, the first electrode 17 becomes a positive electrode and the second electrode becomes a negative electrode. On the other hand, in the fourth state, a voltage is applied from the transformer 133B to the first electrode 17 and the second electrode 18. Therefore, in the fourth state, the first electrode 17 becomes a negative electrode and the second electrode becomes a positive electrode. Therefore, the control unit 136 causes the switching unit 135 to switch between the third state and the fourth state at predetermined intervals, so that the direction of the direct current flowing through the metal pipe material is also switched at predetermined intervals.

With the above configuration, the direction of the direct current flowing through the metal pipe material can be switched by a simple configuration by switching the operation of the electromagnetic switch MC1 and the electromagnetic switch MC2. Since the magnetization in the mold 13 in a predetermined direction can be canceled, the magnetization of the mold 13 can be reduced and the movement of the mold due to the action of the electromagnetic force can be suppressed. The control unit 136 may cause the switching unit 135 to switch a plurality of times during the energization heating, may switch each time the energization heating is performed, or may cause the switching unit 135 to perform the switching each time the energization heating is performed a plurality of times. May be switched to.

Further, since the electromagnetic switch MC3 and the electromagnetic switch MC4 are controlled by the control unit 136, the magnetization of the mold 13 can be reduced and the action of the electromagnetic force can be applied by a simple configuration using a commercially available device. The movement of the mold can be suppressed.

The present invention is not limited to the above-mentioned first embodiment and the second embodiment. The molding apparatus according to the present invention may be an arbitrary modification of the above-mentioned one, as long as the gist of each claim is not changed.

The blow molding die 13 may be either an anhydrous cold die or a water-cooled die. However, the anhydrous cold mold requires a long time to lower the mold to near room temperature after the completion of blow molding. In this respect, if it is a water-cooled mold, cooling is completed in a short time. Therefore, from the viewpoint of improving productivity, a water-cooled mold is desirable.

10 ... Molding device, 11 ... Lower mold, 12 ... Upper mold, 13 ... Mold, 14 ... Metal pipe material, 40 ... Gas supply mechanism (gas supply unit), 17 ... First electrode, 18 ... Second electrode, 120 , 130 ... Power supply unit, 121 ... AC power supply, 143a, 152a ... First power supply side line, 143b, 152b ... Second power supply side line, 123P, 133AP, 133BP ... Positive side output end, 123N, 133AN, 133BN ... Negative output end, 123, 133A, 133B ... Transformer, 145a ... First electrode side line, 145b ... Second electrode side line, 126, 136 ... Control unit, MC1, MC2, MC3, MC4 ... Electromagnetic switch ..

Claims (7)

A molding device that molds metal materials.
At least one of them is movable, and a first mold and a second mold for forming the metal material, and
A pair of electrodes that heat the metal material by energizing the metal material,
A power supply unit that supplies power to the pair of electrodes is provided.
A molding apparatus comprising suppressing the movement of the mold due to the action of an electromagnetic force generated by the magnetized mold when the metal material is energized and heated. The molding apparatus according to claim 1, wherein the molding apparatus is characterized in that the movement of the mold due to the action of an electromagnetic force is suppressed by reducing the magnetization of the mold. The power supply unit includes a switching unit that switches the direction of the current flowing through the metal material.
The molding apparatus according to claim 1 or 2, wherein the switching unit switches the direction of the direct current so as to cancel the magnetization in the predetermined direction in the mold. One of claims 1 to 3, wherein the suppression of the movement of the mold by the action of the electromagnetic force is performed in a state where the first mold and the second mold are open. The molding apparatus according to. The molding apparatus according to claim 3, wherein the switching unit switches the direction of the direct current at any of the timings (i) to (iii).
(I) The direction of the direct current is switched multiple times during one energization heating of the metal material (ii) The direction of the direct current is switched each time the energization heating of the metal material is performed (iii) The metal The direction of the direct current is switched every time the material is energized and heated multiple times. A molding device that expands a metal material to form the metal material.
At least one of them is movable, and a first mold and a second mold for forming the metal material, and
A pair of electrodes that heat the metal material by energizing the metal material,
A power supply unit that supplies power to the pair of electrodes is provided.
The power supply unit is a molding apparatus including a switching unit for switching the direction of a current flowing through a metal material. The molding apparatus according to claim 6, wherein the switching unit switches the direction of an electric current flowing through a metal material in a state where the first mold and the second mold are open.

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