Forming system

A forming system forming a metal pipe by expanding a metal pipe material, includes: a main body part having a forming die for forming the metal pipe; an electrode causing a current to flow through the metal pipe material disposed in the forming die such that the metal pipe material is heated; a power supply unit disposed at a position separated from the main body part and supplying power to the electrode; and a power supply line connecting the power supply unit and the electrode, in which the power supply line includes a lower-side passing portion passing through a lower side of a placing surface on which the main body part is placed, a first connection portion drawn to an upper side of the placing surface and connecting the lower-side passing portion and the electrode, and a second connection portion connecting the lower-side passing portion and the power supply unit.

RELATED APPLICATIONS

The contents of Japanese Patent Application No. 2017-068336, filed Mar. 30, 2017, and of International Patent Application No. PCT/JP2018/012991, filed Mar. 28, 2018, on the basis of each of which priority benefits are claimed in an accompanying application data sheet, are in their entirety incorporated herein by reference.

BACKGROUND

Technical Field

Certain embodiments of the present invention relate to a forming system.

Description of Related Art

In the related art, a forming apparatus in which a metal pipe is closed by a forming die and blow-formed is known. For example, a forming apparatus of the related art includes a forming die, and a gas supply unit which supplies gas into a metal pipe material. In this forming apparatus, the metal pipe material is formed into a shape corresponding to the shape of the forming die by disposing the metal pipe material in the forming die and expanding the metal pipe material by supplying gas from the gas supply unit to the metal pipe material in a state where the forming die is closed.

SUMMARY

According to an embodiment of the present invention, there is provided a forming system which forms a metal pipe by expanding a metal pipe material, including: a main body part having a forming die for forming the metal pipe; an electrode causing an electric current to flow through the metal pipe material disposed in the forming die such that the metal pipe material is heated; a power supply unit which is disposed at a position separated from the main body part and supplies electric power to the electrode; and a power supply line which connects the power supply unit and the electrode, in which the power supply line includes a lower-side passing portion which passes through a lower side of a placing surface on which the main body part is placed, a first connection portion which is drawn to an upper side than the placing surface and connects the lower-side passing portion and the electrode, and a second connection portion which connects the lower-side passing portion and the power supply unit.

DETAILED DESCRIPTION

In the forming apparatus of the related art, the metal pipe material is heated by bringing each electrode into contact with the metal pipe material and performing energization. Therefore, a power supply line for supplying electric power from the power supply unit to the electrode is provided. However, since a large current (for example, several tens of thousands A) flows in the power supply line, there is a case where a leakage magnetic field is generated from the power supply line. There is a case where peripheral equipment in a forming system is affected by such a leakage magnetic field.

Therefore, it is desirable to provide a forming system in which the influence on peripheral equipment of a leakage magnetic field which is generated from a power supply line can be suppressed.

According to this forming system, the power supply line connects the electrode which energizes and heats the metal pipe material and the power supply unit which is disposed at a position separated from the main body part. The power supply line includes the lower-side passing portion which passes through the lower side of the placing surface on the main body part is placed, the first connection portion which is drawn to the upper side of the placing surface and connect the lower-side passing portion and the electrode, and the second connection portion which connects the lower-side passing portion and the power supply unit. In this manner, the power supply line passes through the lower side of the placing surface of the forming die at the lower-side passing portion between the first connection portion and the second connection portion while securing connectivity with the electrode at the first connection portion and securing connectivity with the power supply unit at the second connection portion. In this manner, the lower-side passing portion passes through the lower side of the placing surface, whereby the distance between equipment which is disposed on the placing surface and the lower-side passing portion is increased. Therefore, the influence of a leakage magnetic field from the lower-side passing portion on the equipment which is disposed on the placing surface can be suppressed. By the above, it is possible to suppress the influence on the peripheral equipment of the leakage magnetic field which is generated from the power supply line.

In this forming system, the power supply line may include a positive electrode line and a negative electrode line, and in the lower-side passing portion, the positive electrode line and the negative electrode line may be disposed in parallel at the lower side of the placing surface. In this way, it is possible to dispose the positive electrode line and the negative electrode line in a collected state. The direction of a magnetic field (the direction of a magnetic flux) which is generated by the positive electrode line and the direction of a magnetic field (the direction of a magnetic flux) which is generated by the negative electrode line are opposite to each other. Therefore, the positive electrode line and the negative electrode line are disposed in parallel, whereby it is possible to mutually cancel some magnetic fluxes and further suppress the influence of the leakage magnetic field on peripheral equipment.

In this forming system, a pair of the electrodes may be provided to face each other in a first direction in a horizontal direction so as to support both end sides of the metal pipe material, in a state of being disposed in the forming die, in a longitudinal direction, a die replacement carriage disposition part for allowing a die replacement carriage to advance and retreat may be provided on one side with respect to the main body part in a second direction orthogonal to the first direction in the horizontal direction, a handling unit which performs installation and removal of the metal pipe material with respect to the forming die may be provided on the other side with respect to the main body part in the second direction, and the first connection portion may be drawn to the upper side of the placing surface from a position other than an area on the one side with respect to the main body part in the second direction. In this way, it is possible to prevent the first connection portion from interfering with the die replacement carriage, the forming die, or the like at the time of die replacement.

In this forming system, the first connection portion may be drawn to the upper side of the placing surface from an area on the other side with respect to the main body part in the second direction. In this way, it is possible to prevent the first connection portion from interfering with the die replacement carriage, the forming die, or the like at the time of die replacement. Further, it is not necessary to cause the positive electrode line and the negative electrode line to be greatly branched, compared to a case where the first connection portions are drawn from areas on both sides with respect to the main body part in the first direction, and therefore, the path of the line can be shortened. In this way, it is possible to reduce the resistance of the positive electrode line and the negative electrode line.

In this forming system, the first connection portion may be drawn to the upper side of the placing surface from each of areas on both sides with respect to the main body part in the first direction. In this way, it is possible to prevent the first connection portion from interfering with the die replacement carriage, the forming die, or the like at the time of die replacement. Further, since it is possible to secure spaces at side portions on both sides of the main body part in the second direction, it is possible to dispose peripheral equipment (temperature measuring equipment for measuring the temperature of the die, cooling equipment for cooling the die, or the like) in the spaces.

In this forming system, a cover which covers a portion drawn to the upper side of the placing surface may be provided with respect to at least one of the first connection portion and the second connection portion. In this way, it is possible to suppress the influence of a leakage magnetic field which is generated from the portion of the power supply line, which is drawn to the upper side of the placing surface.

According to the forming system according to the embodiment of the present invention, the influence on peripheral equipment of a leakage magnetic field which is generated from the power supply line can be suppressed.

Hereinafter, a preferred embodiment of a forming system according to the present invention will be described with reference to the drawings. In each drawing, identical or corresponding portions are denoted by the same reference numerals, and overlapping description will be omitted.

FIG. 1is a schematic configuration diagram of a forming apparatus which is included in a forming system according to this embodiment. As shown inFIG. 1, a forming apparatus10for forming a metal pipe is configured to include a forming die13which includes an upper die12and a lower die11, a drive mechanism80for moving at least one of the upper die12and the lower die11, a pipe holding mechanism30for holding a metal pipe material14which is disposed between the upper die12and the lower die11, a heating mechanism50for energizing and heating the metal pipe material14held by the pipe holding mechanism30, a gas supply unit60for supplying high-pressure gas (gas) into the metal pipe material14held between the upper die12and the lower die11and heated, a pair of gas supply mechanisms40and40for supplying the gas from the gas supply unit60into the metal pipe material14held by the pipe holding mechanism30, a water circulation mechanism72for forcibly water-cooling the forming die13, and a control unit70that controls the drive of the drive mechanism80, the drive of the pipe holding mechanism30, the drive of the heating mechanism50, and the gas supply of the gas supply unit60.

The lower die11which is one side of the forming die13is fixed to a base15. The lower die11is formed of a large steel block and is provided with, for example, a rectangular cavity (recessed portion)16on the upper surface thereof. A cooling water passage19is formed in the lower die11, and the lower die11is provided with a thermocouple21inserted from below at substantially the center. The thermocouple21is supported by a spring22so as to be movable up and down.

Further, a space11ais provided in the vicinity of each of the right and left ends (right and left ends inFIG. 1) of the lower die11, and electrodes17and18(lower electrodes) (described later), which are movable parts of the pipe holding mechanism30, and the like are disposed in the spaces11aso as to be able to move up and down. Then, the metal pipe material14is placed on the lower electrodes17and18, whereby the lower electrodes17and18come into contact with the metal pipe material14which is disposed between the upper die12and the lower die11. In this way, the lower electrodes17and18are electrically connected to the metal pipe material14.

Insulating materials91for preventing electric conduction are provided between the lower die11and the lower electrode17, below the lower electrode17, between the lower die11and the lower electrode18, and below the lower electrode18. Each insulating material91is fixed to an advancing and retracting rod95which is a movable portion of an actuator (not shown) configuring the pipe holding mechanism30. The actuator is for moving the lower electrodes17and18and the like up and down, and a fixed portion of the actuator is held on the base15side together with the lower die11.

The upper die12which is the other side of the forming die13is fixed to a slide81(described later) configuring the drive mechanism80. The upper die12is formed of a large steel block and has a cooling water passage25formed in the interior thereof and, for example, a rectangular cavity (recessed portion)24provided on the lower surface thereof. The cavity24is provided at a position facing the cavity16of the lower die11.

Similar to the lower die11, a space12ais provided in the vicinity of each of the right and left ends (right and left ends inFIG. 1) of the upper die12, and electrodes17and18(upper electrodes) (described later), which are movable parts of the pipe holding mechanism30, and the like are disposed in the spaces12aso as to be movable up and down. Then, the upper electrodes17and18move downward in a state where the metal pipe material14is placed on the lower electrodes17and18, whereby the upper electrodes17and18come into contact with the metal pipe material14disposed between the upper die12and the lower die11. In this way, the upper electrodes17,18are electrically connected to the metal pipe material14.

Insulating materials101for preventing electric conduction are provided between the upper die12and the upper electrode17, above the upper electrode17, between the upper die12and the upper electrode18, and above the upper electrode18. Each insulating material101is fixed to an advancing and retracting rod96which is a movable portion of the actuator configuring the pipe holding mechanism30. The actuator is for moving the upper electrodes17and18and the like up and down, and a fixed portion of the actuator is held on the slide81side of the drive mechanism80together with the upper die12.

A semicircular arc-shaped concave groove18acorresponding to the outer peripheral surface of the metal pipe material14is formed in each of the surfaces of the electrodes18and18, which face each other, in the right side portion of the pipe holding mechanism30(refer toFIGS. 2A to 2C), and the metal pipe material14can be placed so as to exactly fit to the portion of the concave groove18a. Similar to the concave groove18a, a semicircular arc-shaped concave groove corresponding to the outer peripheral surface of the metal pipe material14is formed in each of exposed surfaces of the insulating materials91and101, which face each other, in the right side portion of the pipe holding mechanism30. Further, a tapered concave surface18bin which the periphery is recessed to be inclined in a tapered shape toward the concave groove18ais formed on the front surface of the electrode18(the surface in an outer direction of the die). Accordingly, a configuration is made such that, if the metal pipe material14is clamped from an up-down direction at the right side portion of the pipe holding mechanism30, the outer periphery of the right end portion of the metal pipe material14can be exactly surrounded so as to be in close contact over the entire circumference.

A semicircular arc-shaped concave groove17acorresponding to the outer peripheral surface of the metal pipe material14is formed in each of the surfaces of the electrodes17and17, which face each other, in the left side portion of the pipe holding mechanism30(refer toFIGS. 2A to 2C), and the metal pipe material14can be placed so as to exactly fit to the portion of the concave groove17a. Similar to the concave groove18a, a semicircular arc-shaped concave groove corresponding to the outer peripheral surface of the metal pipe material14is formed in each of exposed surfaces of the insulating materials91and101, which face each other, in the left side portion of the pipe holding mechanism30. Further, a tapered concave surface17bin which the periphery is recessed to be inclined in a tapered shape toward the concave groove17ais formed on the front surface of the electrode17(the surface in the outer direction of the die). Accordingly, a configuration is made such that, if the metal pipe material14is clamped from the up-down direction at the left side portion of the pipe holding mechanism30, the outer periphery of the left end portion of the metal pipe material14can be exactly surrounded so as to be in close contact over the entire circumference.

As shown inFIG. 1, the drive mechanism80includes the slide81for moving the upper die12such that the upper die12and the lower die11are combined with each other, a shaft82for generating a driving force for moving the slide81, and a connecting rod83for transmitting the driving force generated by the shaft82to the slide81. The shaft82extends in a right-left direction above the slide81, is rotatably supported, and has an eccentric crank82awhich protrudes from the right and left ends and extends in the right-left direction at a position separated from the shaft center thereof. The eccentric crank82aand a rotary shaft81aprovided above the slide81and extending in the right-left direction are connected to each other by the connecting rod83. In the drive mechanism80, the height in the up-down direction of the eccentric crank82ais changed by controlling the rotation of the shaft82by the control unit70, and the up-and-down movement of the slide81can be controlled by transmitting the positional change of the eccentric crank82ato the slide81through the connecting rod83. Here, the oscillation (rotational movement) of the connecting rod83, which occurs when the positional change of the eccentric crank82ais transmitted to the slide81, is absorbed by the rotary shaft81a. The shaft82rotates or stops in response to the drive of a motor or the like, which is controlled by the control unit70, for example.

The heating mechanism50includes a power supply unit55, and a power supply line52which electrically connects the power supply unit55and the electrodes17and18. The power supply unit55includes a direct-current power supply and a switch, and can energize the metal pipe material14through the power supply line52and the electrodes17and18in a state where the electrodes17and18are electrically connected to the metal pipe material14. Here, the power supply line52is connected to the lower electrodes17and18.

In the heating mechanism50, the direct-current current output from the power supply unit55is transmitted by the power supply line52and input to the electrode17. Then, the direct-current current passes through the metal pipe material14and is input to the electrode18. Then, a direct-current current is transmitted by the power supply line52and input to the power supply unit55.

Returning toFIG. 1, each of the pair of gas supply mechanisms40includes a cylinder unit42, a cylinder rod43which advances and retreats in accordance with the operation of the cylinder unit42, and a seal member44connected to the tip of the cylinder rod43on the pipe holding mechanism30side. The cylinder unit42is placed on and fixed to a block41. A tapered surface45which is tapered is formed on the tip of the seal member44, and is configured in a shape which is fitted to the tapered concave surfaces17band18bof the electrodes17and18(refer toFIGS. 2A and 2B). A gas passage46which extends from the cylinder unit42side toward the tip and through which the high-pressure gas supplied from the gas supply unit60flows, as specifically shown in detail inFIGS. 2A and 2B, is provided in the seal member44.

The gas supply unit60includes a gas source61, an accumulator62for storing the gas supplied by the gas source61, a first tube63extending from the accumulator62to the cylinder unit42of the gas supply mechanism40, a pressure control valve64and a switching valve65provided in the first tube63, a second tube67extending from the accumulator62to the gas passage46formed in the seal member44, and a pressure control valve68and a check valve69provided in the second tube67. The pressure control valve64plays a role of supplying a gas having an operating pressure adapted to a pressing force of the seal member44against the metal pipe material14to the cylinder unit42. The check valve69plays a role of preventing the high-pressure gas from flowing backward in the second tube67. The pressure control valve68provided in the second tube67plays a role of supplying a gas having an operating pressure for expanding the metal pipe material14to the gas passage46of the seal member44by the control of the control unit70.

The control unit70can supply a gas having a desired operating pressure into the metal pipe material14by controlling the pressure control valve68of the gas supply unit60. Further, the control unit70acquires temperature information from the thermocouple21from information which is transmitted from (A) shown inFIG. 1, and controls the drive mechanism80, the power supply unit55, and the like.

The water circulation mechanism72includes a water tank73for storing water, a water pump74for pumping up the water stored in the water tank73, pressurizing it, and sending it to the cooling water passage19of the lower die11and the cooling water passage25of the upper die12, and a pipe75. Although omitted, a cooling tower for lowering a water temperature or a filter for purifying water may be provided in the pipe75.

<Method of Forming Metal Pipe using Forming Apparatus>

Next, a method of forming a metal pipe using the forming apparatus10will be described. First, the quenchable steel grade cylindrical metal pipe material14is prepared. The metal pipe material14is placed (loaded) on the electrodes17and18provided on the lower die11side by using, for example, a robot arm or the like. Since the concave grooves17aand18aare formed in the electrodes17and18, the metal pipe material14is positioned by the concave grooves17aand18a.

Next, the control unit70controls the drive mechanism80and the pipe holding mechanism30, thereby causing the pipe holding mechanism30to hold the metal pipe material14. Specifically, the upper die12, the upper electrodes17and18, and the like held on the slide81side move to the lower die11side by the drive of the drive mechanism80, and both end portions of the metal pipe material14are clamped from above and below by the pipe holding mechanism30by operating the actuator which allows the upper electrodes17and18and the like and the lower electrodes17and18and the like, which are included in the pipe holding mechanism30, to advance and retreat. The clamping is performed in such an aspect as to be in close contact over the entire circumference in the vicinity of both end portions of the metal pipe material14due to the presence of the concave grooves17aand18aformed in the electrodes17and18and the concave grooves formed in the insulating materials91and101.

At this time, as shown inFIG. 2A, the end portion of the metal pipe material14on the electrode18side protrudes further toward the seal member44side than the boundary between the concave groove18aof the electrode18and the tapered concave surface18bin an extending direction of the metal pipe material14. Similarly, the end portion of the metal pipe material14on the electrode17side protrudes further toward the seal member44side than the boundary between the concave groove17aof the electrode17and the tapered concave surface17bin the extending direction of the metal pipe material14. Further, the lower surfaces of the upper electrodes17and18and the upper surfaces of the lower electrodes17and18are in contact with each other. However, there is no limitation to the configuration of being in close contact over the entire circumference of each of both end portions of the metal pipe material14, and a configuration may be made such that the electrodes17and18are in contact with a part in the circumferential direction of the metal pipe material14.

Subsequently, the control unit70controls the heating mechanism50to heat the metal pipe material14. Specifically, the control unit70controls the power supply unit55of the heating mechanism50to supply electric power. Then, the electric power which is transmitted to the lower electrodes17and18through the power supply line52is supplied to the upper electrodes17and18clamping the metal pipe material14and the metal pipe material14, and due to resistance which exists in the metal pipe material14, the metal pipe material14itself generates heat by Joule heat. That is, the metal pipe material14is in the energized and heated state.

Subsequently, the forming die13is closed to the heated metal pipe material14by the control of the drive mechanism80by the control unit70. In this way, the cavity16of the lower die11and the cavity24of the upper die12are combined, and the metal pipe material14is disposed and sealed in the cavity portion between the lower die11and the upper die12.

Thereafter, the both ends of the metal pipe material14are sealed by advancing the seal member44by operating the cylinder unit42of the gas supply mechanism40. At this time, as shown inFIG. 2B, the seal member44is pressed against the end portion of the metal pipe material14on the electrode18side, whereby the portion protruding further toward the seal member44than the boundary between the concave groove18aand the tapered concave surface18bof the electrode18is deformed in a funnel shape so as to follow the tapered concave surface18b. Similarly, the seal member44is pressed against the end portion of the metal pipe material14on the electrode17side, whereby the portion protruding further toward the seal member44than the boundary between the concave groove17aand the tapered concave surface17bof the electrode17is deformed in a funnel shape so as to follow the tapered concave surface17b. After the completion of the sealing, a high-pressure gas is blown into the metal pipe material14to form the metal pipe material14softened by heating so as to follow the shape of the cavity portion.

The metal pipe material14is softened by being heated to a high temperature (about 950° C.), and therefore, the gas supplied into the metal pipe material14thermally expands. For this reason, for example, the gas to be supplied is set to be compressed air, and thus the metal pipe material14having a temperature of 950° C. can be easily expanded by the thermally expanded compressed air.

The outer peripheral surface of the blow-formed and expanded metal pipe material14is rapidly cooled in contact with the cavity16of the lower die11and at the same time, is rapidly cooled in contact with the cavity24of the upper die12(since the upper die12and the lower die11have large heat capacity and are controlled to a low temperature, if the metal pipe material14comes into contact with the upper die12and the lower die11, the heat of the pipe surface is removed to the die side at once), and thus quenching is performed. Such a cooling method is called die contact cooling or die cooling. Immediately after the rapid cooling, austenite is transformed into martensite (hereinafter, the transformation of austenite to martensite is referred to as martensitic transformation). Since a cooling rate is reduced in the second half of the cooling, the martensite is transformed into another structure (troostite, sorbite, or the like) due to reheating. Therefore, it is not necessary to separately perform tempering treatment. Further, in this embodiment, instead of the die cooling or in addition to the die cooling, cooling may be performed by supplying a cooling medium into, for example, the cavity24. For example, the martensitic transformation may be generated by performing cooling by bringing the metal pipe material14into contact with the dies (the upper die12and the lower die11) before a temperature at which the martensitic transformation begins, and then performing the die opening and blowing a cooling medium (cooling gas) to the metal pipe material14.

As described above, the metal pipe material14is blow-formed and then cooled, and then the die opening is performed, thereby obtaining a metal pipe having, for example, a substantially rectangular tubular main body portion.

Next, a forming system100according to this embodiment will be described with reference toFIGS. 3 to 5. As shown inFIGS. 3 and 4, the forming system100includes the forming apparatus10which includes the forming die13, the electrodes17and18, the power supply unit55, and the power supply line52, a placing table105, a die replacement carriage disposition part102(refer toFIG. 4), and a handling unit103(refer toFIG. 4). The unit including the forming die13, the base15, the gas supply mechanism40, the block41, and the drive mechanism80(refer toFIG. 1) is referred to as a main body part110of the forming system100. The pair of gas supply mechanisms40and the blocks41are disposed to interpose the base15therebetween. In the placing table105, the main body part110, the power supply unit55, the die replacement carriage disposition part102, and the handling unit103are placed on a placing surface105a(refer toFIG. 4).

In this embodiment, a direction in which the electrodes17and18face each other in the horizontal direction is set to be an “X-axis direction”, a direction orthogonal to the X-axis direction in the horizontal direction is set to be a “Y-axis direction”, and the up-down direction is set to be a “Z-axis direction”. Further, the electrode18side is set to be a positive side in the X-axis direction, and the electrode17side is set to be a negative side in the X-axis direction. One side in the Y-axis direction is set to be a positive side, and the other side in the Y-axis direction is set to be a negative side. The upper side is set to be a positive side in the Z-axis direction, and the lower side is set to be a negative side in the Z-axis direction. The X-axis direction corresponds to a “first direction” in the claims, and the Y-axis direction corresponds to a “second direction” in the claims.

As shown inFIG. 4, the die replacement carriage disposition part102is a structure for allowing a die replacement carriage111to advance and retreat. The die replacement carriage disposition part102is provided on the positive side with respect to the main body part110in the Y-axis direction. The die replacement carriage disposition part102includes a rail part102afor allowing the die replacement carriage111to advance and retreat in the X axis direction, and a rail part102bfor allowing the die replacement carriage111to advance and retreat in the Y axis direction. The rail part102ais provided at a position separated from the main body part110to the positive side in the Y-axis direction. The rail part102bextends in the Y-axis direction from the rail part102ato the position on the front side of the main body part110.

The handling unit103is a device for performing installation and removal of the metal pipe material14with respect to the forming die13. The handling unit103is configured of, for example, a robot arm. The handling unit103is provided on the negative side with respect to the main body part110in the Y-axis direction.

The power supply unit55is disposed at a position separated from the main body part110and is a device for supplying electric power to the electrodes17and18through the power supply line52. In this embodiment, the power supply line is configured of a bus bar. In a case where the electrode17is set to be a positive electrode and the electrode18is set to be a negative electrode, the power supply line52includes a positive electrode line52A connecting the power supply unit55and the electrode17, and a negative electrode line52B connecting the power supply unit55and the electrode18. However, there is no particular limitation on which of the electrode17and the electrode18is set as a positive electrode or a negative electrode. Therefore, the electrode17may be set as a negative electrode and the electrode18may be set as a positive electrode. In this case, the line52A serves as a negative electrode line and the line52B serves as a positive electrode line.

Next, schematic disposition of the power supply line52will be described with reference toFIG. 3. The power supply line52shown inFIG. 3schematically shows a positional relationship with other constituent elements. As shown inFIG. 3, the positive electrode line52A and the negative electrode line52B of the power supply line52respectively include lower-side passing portions121A and121B, first connection portions122A and122B, and second connection portions123A and123B. The lower-side passing portions121A and121B are portions which pass through the lower side of the placing surface105aof the placing table105. The first connection portions122A and122B are portions which connect the lower-side passing portions121A and121B and the electrodes17and18, respectively. The second connection portions123A and123B are portions which connect the lower-side passing portions121A and121B and the power supply unit55.

The first connection portions122A and122B are drawn to the upper side of the placing surface105a. The second connection portions123A and123B are drawn to the upper side of the placing surface105a. With respect to the first connection portions122A and122B, a cover140which covers the whole or a part of the portion which is drawn to the upper side of the placing surface105ais provided. InFIG. 3, apart of the cover140is omitted in order to show the configuration around the forming die13. With respect to the second connection portions123A and123B, a cover141which covers the whole or a part of the portion which is drawn to the upper side of the placing surface105ais provided.

Next, the detailed configurations of the positive electrode line52A and the negative electrode line52B of the power supply line52will be described with reference toFIGS. 4 and 5. The portions shown by broken lines inFIGS. 4 and 5are portions which are disposed below the placing surface105a. InFIGS. 4 and 5, the covers140and141are omitted. InFIG. 5, in order to clarify the shape of the power supply line52, only the power supply line52, the electrodes17and18, and the power supply unit55are shown.

As shown inFIGS. 4 and 5, in this embodiment, the power supply unit55is disposed at a position separated from the main body part110to the negative side in the X-axis direction. The lower-side passing portions121A and121B are disposed at positions separated further toward the negative side in the Y-axis direction than the main body part110and the power supply unit55. The first connection portions122A and122B are drawn upward from the end portions on the positive side in the X-axis direction of the lower-side passing portions121A and121B, and are connected to the electrodes17and18, respectively. Further, the second connection portions123A and123B are drawn upward from the end portions on the negative side in the X-axis direction of the lower-side passing portions121A and121B, and are connected to the power supply unit55. Each portion of the positive electrode line52A and the negative electrode line52B in the following description is configured of a long plate member extending in a state of having a thickness direction in any direction in the horizontal direction.

Specifically, the lower-side passing portions121A and121B include straight portions121Aa and121Ba, bent portions121Ab and121Bb, and bent portions121Ac and121Bc. The straight portions121Aa and121Ba are portions which extend straight in the X-axis direction. The bent portions121Ab and121Bb are portions which are bent from the end portions on the positive side in the X-axis direction of the straight portions121Aa and121Ba to the positive side in the Y-axis direction toward the main body part110. The bent portions121Ac and121Bc are portions which are bent from the end portions on the negative side in the X-axis direction of the straight portions121Aa and121Ba to the positive side in the Y-axis direction toward the power supply unit55. The straight portion121Aa is disposed further on the positive side in the Y-axis direction than the straight portion121Ba. The bent portion121Ab is disposed further on the negative side in the X-axis direction than the bent portion121Bb. The bent portion121Ac is disposed further on the positive side in the X-axis direction than the bent portion121Bc.

The first connection portions122A and122B extend upward from the end portions of the lower-side passing portions121A and121B, extend toward the positive side in the Y-axis direction toward the main body part110, are branched from each other on the front side of the main body part110, and are connected to the electrode17and the electrode18, respectively. Specifically, the first connection portions122A and122B include rising portions122Aa and122Ba, straight portions122Ab and122Bb, branched portions122Ac and122Bc, and connection portions122Ad and122Bd. The rising portions122Aa and122Ba are portions which extend straight upward from the end portions on the positive side in the Y-axis direction of the bent portions121Ab and121Bb of the lower-side passing portions121A and121B. The rising portions122Aa and122Ba extend to the height positions of the electrodes17and18. The straight portions122Ab and122Bb extend straight from the upper end portions of the rising portions122Aa and122Ba to the front side of the forming die13toward the positive side in the Y-axis direction. The first connection portions122A and122B are branched so as to extend in the opposite directions to each other at the branch portions122Ac and122Bc. That is, the branch portion122Ac extends from the end portion on the positive side in the Y-axis direction of the straight portion122Ab to the negative side in the X-axis direction. The connection portion122Ad extends from the end portion on the negative side in the X-axis direction of the branch portion122Ac to the positive side in the Y-axis direction and is connected to the electrode17. The branch portion122Bc extends from the end portion on the positive side in the Y-axis direction of the straight portion122Bb to the positive side in the X-axis direction. The connection portion122Bd extends from the end portion on the positive side in the X-axis direction of the branch portion122Bc to the positive side in the Y-axis direction and is connected to the electrode18. The branch portions122Ac and122Bc branch at positions closer to the electrode17. Therefore, the length of the branch portion122Bc is longer than that of the branch portion122Ac.

The second connection portions123A and123B extend upward from the end portions of the lower-side passing portions121A and121B, extend toward the positive side in the Y-axis direction toward the power supply unit55, and are connected to the power supply unit55. Specifically, the second connection portions123A and123B include rising portions123Aa and123Ba, and connection portions123Ab and123Bb. The rising portions123Aa and123Ba extend to the height positions of the electrodes17and18. The connection portions123Ab and123Bb extend from the upper end portions of the rising portions123Aa and123Ba toward the positive side in the Y-axis direction and are connected to the power supply unit55.

In the lower-side passing portions121A and121B, the positive electrode line52A and the negative electrode line52B are disposed in parallel at the lower side of the placing surface105a. That is, in the lower-side passing portions121A and121B, the straight portions121Aa and121Ba, the bent portions121Ab and121Bb, and the bent portions121Ac and121Bc are disposed to extend in parallel with a predetermined gap therebetween. Also in the first connection portions122A and122B, the rising portions122Aa and122Ba and the straight portions122Ab and122Bb are disposed to extend in parallel with a predetermined gap therebetween.

Here, as described above, the die replacement carriage disposition part102is disposed at an area on the positive side with respect to the main body part110in the Y-axis direction. The area is set to be an area E1between both the end portions110aand110bin the X-axis direction of the main body part110(inFIG. 4, an area between a straight line L1and a straight line L2). The first connection portions122A and122B are drawn to the upper side of the placing surface105afrom positions other than the area E1. In this embodiment, the first connection portions122A and122B are drawn to the upper side of the placing surface105afrom the area on the negative side with respect to the main body part110in the Y-axis direction. That is, the first connection portions122A and122B are drawn to the upper side of the placing surface105afrom an area where the handling unit103is disposed, not at the die replacement carriage disposition part102.

Next, the operation and effects of the forming system100according to this embodiment will be described.

According to the forming system100of this embodiment, the power supply line52connects the electrodes17and18which energize and heat the metal pipe material14and the power supply unit55which is disposed at a position separated from the main body part110. The power supply line52includes the lower-side passing portions121A and121B which pass through the lower side of the placing surface105aon which the main body part110is placed, the first connection portions122A and122B which are drawn to the upper side of the placing surface105aand connect the lower-side passing portions121A and121B and the electrodes17and18, and the second connection portions123A,123B which connect the lower-side passing portions121A and121B and the power supply unit55. In this manner, the power supply line52passes through the lower side of the placing surface105aof the forming die13at the lower-side passing portions121A and121B between the first connection portions122A and122B and the second connection portions123A and123B while securing connectivity with the electrodes17and18at the first connection portions122A and122B and securing connectivity with the power supply unit55at the second connection portions123A and123B. In this manner, the lower-side passing portions121A and121B pass through the lower side of the placing surface105a, whereby the distance between equipment which is disposed on the placing surface105aand the lower-side passing portions121A and121B is increased. Therefore, the influence of a leakage magnetic field from the lower-side passing portions121A and121B on the equipment which is disposed on the placing surface105acan be suppressed. By the above, it is possible to suppress the influence on the peripheral equipment of the leakage magnetic field which is generated from the power supply line.

Further, the power supply line52has the lower-side passing portions121A and121B, whereby the space above the placing surface105acan be widely used. Further, the movement of a worker also becomes easy.

In the forming system100, the power supply line52includes the positive electrode line52A and the negative electrode line52B, and in the lower-side passing portions121A and121B, the positive electrode line52A and the negative electrode line52B are disposed in parallel at the lower side of the placing surface105a. In this way, it is possible to dispose the positive electrode line52A and the negative electrode line52B in a collected state. The direction of a magnetic field (the direction of a magnetic flux) which is generated by the positive electrode line52A and the direction of a magnetic field (the direction of a magnetic flux) which is generated by the negative electrode line52B are opposite to each other. Therefore, the positive electrode line52A and the negative electrode line52B are disposed in parallel, whereby it is possible to mutually cancel some magnetic fluxes and further suppress the influence of the leakage magnetic field on the peripheral equipment.

In the forming system100, the electrodes17and18are provided in a pair to face each other in the X-axis direction so as to support both end sides in the longitudinal direction of the metal pipe material14in a state of being disposed in the forming die13, the die replacement carriage disposition part102for allowing the die replacement carriage111to advance and retreat is provided on the positive side with respect to the main body part110in the Y-axis direction, the handling unit103which performs installation and removal of the metal pipe material14with respect to the forming die13is provided on the negative side with respect to the main body part110in the Y-axis direction, and the first connection portions122A and122B are drawn to the upper side of the placing surface105afrom positions other than the area E1on the positive side with respect to the main body part110in the Y-axis direction. In this way, it is possible to prevent the first connection portions122A and122B from interfering with the die replacement carriage111, the forming die13, or the like at the time of die replacement.

In the forming system100, the first connection portions122A and122B are drawn to the upper side of the placing surface105afrom the area on the negative side with respect to the main body part110in the Y-axis direction. In this way, it is possible to prevent the first connection portions122A and122B from interfering with the die replacement carriage111, the forming die13, or the like at the time of die replacement. Further, it is not necessary to cause the positive electrode line52A and the negative electrode line52B to be greatly branched, compared to a case where the first connection portions122A and122B are drawn from areas on both sides with respect to the main body part110in the X-axis direction, as shown inFIG. 9, and therefore, the path of the line can be shortened. In this way, it is possible to reduce the resistance of the positive electrode line52A and the negative electrode line52B.

In the forming system100, the covers140and141which cover the portions drawn to the upper side of the placing surface105aare provided with respect to the first connection portions122A and122B and the second connection portions123A and123B. In this way, it is possible to suppress the influence of the leakage magnetic field which is generated from the portion of the power supply line52, which is drawn to the upper side of the placing surface105a.

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

For example, a power supply line152as shown inFIGS. 6 and 7may be adopted. A positive electrode line152A and a negative electrode line152B of the power supply line152shown inFIGS. 6 and 7are mainly different from the positive electrode line52A and the negative electrode line52B of the power supply line52shown inFIGS. 4 and 5in that the direction in which lower-side passing portions221A and221B extend is different from that in the power supply line52. The power supply unit55is disposed at a position separated from the main body part110to the positive side in the Y-axis direction. Therefore, the lower-side passing portions221A and221B of the positive electrode line152A and the negative electrode line152B extend in the Y-axis direction from the power supply unit55toward the main body part110. Further, the lower-side passing portions221A and221B pass through the lower side of the main body part110and extend to a position on the negative side in the Y-axis direction of the main body part110. In this way, first connection portions222A and222B are drawn to the upper side of the placing surface105afrom an area on the negative side with respect to the main body part110in the Y-axis direction. The first connection portions222A and222B have configurations having the same gist as those of the first connection portions122A and122B shown inFIGS. 4 and 5. Second connection portions223A and223B have configurations having the same gist as those of the second connection portions123A and123B shown inFIGS. 4 and 5.

Further, for example, a power supply line252as shown inFIGS. 8 and 9may be adopted. A positive electrode line252A and a negative electrode line252B of the power supply line252shown inFIGS. 8 and 9are mainly different from the positive electrode line52A and the negative electrode line52B of the power supply line52shown inFIGS. 4 and 5in that the configurations of lower-side passing portions321A and321B, drawing structure of first connection portions322A and322B, and drawing structure of second connection portions323A and323B are different from those in the power supply line52.

The power supply unit55is disposed at a position separated from the main body part110to the positive side in the Y-axis direction. Further, the power supply unit55is not provided on the placing surface105aof the placing table105and is disposed at a position separated from an end portion105bon the positive side in the Y-axis direction of the placing table105. Therefore, the second connection portions323A and323B are not drawn to the upper side of the placing surface105aand are drawn straight from the lower-side passing portions321A and321B through the end portion105b. In this manner, the second connection portions323A and323B may not be drawn to the upper side of the placing surface105a. In a case where the power supply unit55is close to the end portion105bof the placing table105, the second connection portions323A and323B are also disposed below the placing surface105a. In this case, the second connection portions323A and323B may be regarded as simultaneously configuring the lower-side passing portions. Further, the first connection portion322A is drawn to the upper side of the placing surface105afrom an area on the negative side in the X-axis direction with respect to the main body part110and is connected to the electrode17. The first connection portion322A includes a rising portion322Aa extending upward, and a connection portion322Ab which extends from the rising portion322Aa to the electrode17side and is connected to the electrode17. The first connection portion322B is drawn to the upper side of the placing surface105afrom an area on the positive side in the X-axis direction with respect to the main body part110and is connected to the electrode18. The first connection portion322B includes a rising portion322Ba extending upward, and a connection portion322Bb which extends from the rising portion322Ba to the electrode18side and is connected to the electrode18.

With such a configuration, the lower-side passing portions321A and321B are branched from the second connection portions323A and323B, then greatly bypass, and are connected to the first connection portions322A and322B, respectively. The lower-side passing portion321A includes a branch portion321Aa which extends from the second connection portion323A to the negative side in the X-axis direction, a bent portion321Ab which is bent from the branch portion321Aa and extends to the negative side in the Y-axis direction, and a connection portion321Ac which extends from the bent portion321Ab to the positive side in the X-axis direction and is connected to the first connection portion322A. The lower-side passing portion321B includes a branch portion321Ba which extends from the second connection portion323B to the positive side in the X-axis direction, a bent portion321Bb which is bent from the branch portion321Ba and extends to the negative side in the Y-axis direction, and a connection portion321Bc which extends from the bent portion321Bb to the negative side in the X-axis direction and is connected to the first connection portion322B.

In the power supply line252shown inFIGS. 8 and 9, the first connection portions322A and322B are drawn to the upper side of the placing surface105afrom areas on both sides with respect to the main body part110in the X-axis direction. In this way, it is possible to prevent the first connection portions322A and322B from interfering with the die replacement carriage111, the forming die13, or the like at the time of die replacement. Further, since it is possible to secure spaces at side portions on both the positive and negative sides of the main body part110in the Y-axis direction, it is possible to dispose peripheral equipment (temperature measuring equipment for measuring the temperature of the die, cooling equipment for cooling the die, or the like) in the spaces.