JP2016081764A - Electrification heating apparatus for plated metal sheet for hot stamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrification heating apparatus for a plated metal sheet for hot stamp capable of reducing eccentricity of a plating layer by reducing a Lorentz force that acts on a molten plating layer, rather than a conventional electrification heating apparatus.SOLUTION: An electrification heating apparatus 30 comprises: a first auxiliary electrification cylinder 12 including first and second end portions which are disposed while being aligned with first and second end portions of a plated metal sheet 11; a second auxiliary electrification cylinder 13 including first and second end portions which are disposed while being aligned with the first and second end portions of the plated metal sheet 11; and a power unit which is connected to the first and second end portions of the plated metal sheet 11 and the first and second end portions of each of the first and second auxiliary electrification cylinders 12 and 13, makes a current flow to the plated metal sheet 11 and makes a current flow to each of the first and second auxiliary electrification cylinders 12 and 13 in a direction reverse to the curent that flows to the plated metal sheet 11.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an apparatus for energizing and heating a plated metal plate for hot stamping, for example, a plated steel plate for automobile parts.

  One method for forming a high-strength metal plate (for example, a steel plate) into a desired shape is a hot stamp method. In the hot stamping method, for example, when the metal plate is a steel plate, press forming is performed in a state where the steel plate is heated to an austenitizing temperature (or A3 transformation point) or higher. Currently, heating of a metal plate is often performed using a furnace, but current-carrying heating has attracted attention as a method for heating the metal plate to a desired temperature in a shorter time.

  It is known that when a surface of a metal plate having a low melting point metal plated, for example, a steel plate plated with Al is energized and heated, the plated metal moves in a specific direction. Specifically, a part of the plating metal moves in the in-plane direction of the metal plate and in a direction orthogonal to the direction of the current flowing through the metal plate, and as a result, a thin portion and a thick portion are generated in the plating layer. . Hereinafter, the phenomenon in which the plating metal moves is also referred to as “the proximity of the plating layer”.

  When the plating layer is deviated, the appearance of the molded product is impaired, and the corrosion resistance is lowered at a portion where the plating layer is thin. It is considered that the shift of the plating layer is caused by the fact that a melt of the plating layer is generated by heating, and the Lorentz force due to the current flowing in the melt acts.

  Various methods have been proposed to prevent such a shift of the plating layer. In Patent Literature 1, auxiliary current carrying plates having side edges extending across an insulating gap with respect to side edges extending in the direction in which the current flows in the plated steel sheet are arranged in the same plane as the plated steel sheet, There has been proposed a device for energizing a current plate with a current of the same phase. In this apparatus, at least a part of the Lorentz force due to the current flowing through the metal plate is canceled out by the Lorentz force due to the current flowing through the auxiliary energization plate.

  Patent Document 2 proposes an apparatus in which a ferromagnetic magnetic flux derivative having a wall surface orthogonal to the surface of a plated steel sheet is disposed along a side surface extending in the direction in which the current of the plated steel sheet flows. An insulating gap is provided between the side surface of the plated steel plate and the wall surface of the magnetic flux derivative. In this apparatus, at least a part of the Lorentz force is canceled by controlling the magnetic field generated by the direct current flowing through the metal plate with the magnetic flux derivative.

  In Patent Document 3, a metal conductor having the same shape as a hot stamping plating metal plate and a hot stamping plating metal plate are arranged in parallel at the same position, and the hot stamping plating metal plate and the metal conductor are electrically connected. It is proposed to connect and energize.

  FIG. 1A shows an example of an electrical connection mode between a plated metal plate and a metal conductor in the energization heating apparatus disclosed in Patent Document 3, and FIG. 1B shows an energization circuit thereof. 1A and 1B are considered to be able to maximize the effect of suppressing the shift of the plating layer among the various aspects disclosed in Patent Document 3.

  This electric heating apparatus includes plate-like metal conductors 4A and 4B having a longitudinal shape. The metal conductor 4A and the metal conductor 4B have the same shape (the planar shape is the same as that of the hot stamp material 1) and are made of the same material. The material for hot stamping (plated metal plate) 1 and the metal conductors 4A and 4B are arranged with their positions aligned. The metal conductors 4A and 4B are respectively opposed to the front and back surfaces of the hot stamp material 1 with a gap. The distance L1 between the hot stamp material 1 and the metal conductor 4A is equal to the distance L2 between the hot stamp material 1 and the metal conductor 4B.

  With respect to each of the hot stamp material 1 and the metal conductors 4A and 4B, the feeding member 2 is electrically connected to both ends in the longitudinal direction. Both the hot stamp material 1 and the metal conductors 4A and 4B are supported by the power supply member 2.

  A power source 3 is connected to the end portion of the hot stamp material 1 and the end portions of the metal conductors 4 </ b> A and 4 </ b> B via the power supply member 2. The hot stamp material 1 and the metal conductors 4A and 4B are connected in series to the power source 3, and the metal conductor 4A and the metal conductor 4B are connected in parallel. The direction of the current flowing through each of the metal conductors 4A and 4B is opposite to the direction of the current flowing through the hot stamp material 1.

JP 2012-115864 A JP 2012-166242 A JP 2012-221784 A

  However, in the devices of Patent Documents 1 and 2, the effect of suppressing the shift of the plating layer is not sufficient, and in particular, when the width of the plated steel plate is wide, the effect of arranging the auxiliary energizing plate or the magnetic flux derivative is limited. It will be something like that.

  On the other hand, when using the apparatus of patent document 3, the area | region where the shift | offset | difference of a plating layer is suppressed becomes wide regarding the width direction of the raw material for hot stamping. However, when the plated metal plate is energized and heated, the metal conductor is heated by receiving radiant heat from the heated material for hot stamping. When the temperature of the metal conductor becomes higher than a certain level, the rigidity of the metal conductor is remarkably lowered, and the metal conductor is easily bent.

  Furthermore, the Lorentz force acts in the out-of-plane direction, that is, away from the hot stamp material, on the metal conductor due to the magnetic field generated by energizing the hot stamp material and the metal conductor and the current flowing in the metal conductor. . In the case where a metal conductor having a small plate thickness and a small rigidity (second moment of cross section with respect to the deflection direction) is used, the metal conductor can be bent by this Lorentz force.

  When the metal conductor bends, the distance between the metal conductor and the hot stamp material changes. In this case, if the energization conditions for minimizing the Lorentz force are optimized without considering the deflection of the metal conductor, the desired Lorentz force suppression effect cannot be obtained.

  Accordingly, an object of the present invention is an energization heating device for hot stamping plated metal plates, particularly hot stamping plated steel plates, and the Lorentz force acting on the molten plating layer is made smaller than that of a conventional energization heating device. And it is providing the electricity heating apparatus which can reduce the shift | offset | difference of a plating layer.

The gist of the present invention is as follows.
An energization heating device that energizes and heats a plated metal plate for hot stamping having first and second ends,
A first auxiliary current-carrying cylinder having first and second end portions arranged in alignment with the first and second end portions of the plated metal plate, respectively;
A second auxiliary current-carrying cylinder having first and second ends that are arranged in alignment with the first and second ends of the plated metal plate, respectively.
The first and second end portions of the plated metal plate and the first and second end portions of the first and second auxiliary current-carrying cylinders are connected to flow current to the plated metal plate, and the first Each of the first and second auxiliary energization cylinders is provided with a power supply device for flowing a current in a direction opposite to the current flowing in the plated metal plate,
A plating layer having a width Wx (0 <Wx ≦ W) with respect to a width W of the plated metal plate is formed on the plated metal plate;
The first auxiliary energization cylinder includes a first flat plate portion having a width of 0.95 × Wx or more, and the first flat plate portion has a width direction center of the first flat plate portion and a width direction of the plating layer. Are aligned with the center of the metal plate and opposed to the first surface of the plated metal plate,
The second auxiliary energization cylinder includes a second flat plate portion having a width of 0.95 × Wx or more, and the second flat plate portion has a width direction center of the second flat plate portion and a width direction of the plating layer. An electric heating apparatus for a hot stamping plated metal plate, the center of which is aligned with the second surface of the plated metal plate.

  In the energization heating device of the present invention, an auxiliary energization cylinder is provided instead of the metal conductor (auxiliary energization plate) which is a plate-like member in the conventional energization heating device. As long as the material of the cylinder is the same as that of the plate material, the bending rigidity can be increased under the conditions of the same weight and the same design space (space size where the auxiliary energization member can be installed), so that it is difficult to bend. In addition, a cooling medium such as cooling water can flow inside the auxiliary energizing cylinder, and in this case, the temperature of the auxiliary energizing cylinder can be prevented from rising during energization heating of the plated metal plate. This also can suppress the deflection of the auxiliary energizing plate.

  When the auxiliary energizing plate is used, if the temperature rises excessively and deflection occurs, increase the distance between the plated metal plate and the auxiliary energizing plate to avoid contact between the plated metal plate and the auxiliary energizing plate. It is necessary to take. Even in such a case, if the auxiliary energizing cylinder is used instead of the auxiliary energizing plate, the auxiliary energizing cylinder is difficult to bend, so that the distance from the plated metal plate can be reduced. Therefore, the degree of freedom of setting can be increased in the process of determining an appropriate energization heating condition that can reduce the Lorentz force as a whole for the same plated metal plate. For this reason, compared with the case where an auxiliary energizing plate is used, the Lorentz force acting on the molten plating layer can be reduced and the deviation of the plating layer can be reduced.

FIG. 1A is a diagram showing an electrical connection mode of a hot stamp material and a metal conductor when a conventional energization heating apparatus is used. FIG. 1B is a diagram showing a hot stamping material and a metal conductor energization circuit shown in FIG. 1A. FIG. 2 is a diagram illustrating a configuration of the energization heating device according to the first embodiment of the present invention. FIG. 3 is a diagram showing a configuration of an energization heating apparatus according to the second embodiment of the present invention. FIG. 4A is a cross-sectional view of a first auxiliary energizing cylinder and a plated metal plate provided in an energization heating apparatus according to a third embodiment of the present invention. FIG. 4B is a cross-sectional view of the first auxiliary energizing cylinder and the plated metal plate provided in the energization heating apparatus according to the fourth embodiment of the present invention. FIG. 4C is a cross-sectional view of the first auxiliary energizing cylinder and the plated metal plate provided in the energization heating apparatus according to the fifth embodiment of the present invention. FIG. 5 is a cross-sectional view of an energization heating apparatus which is a target for calculating temperature and deflection during energization.

Hereinafter, with reference to the drawings, embodiments of the current heating device of the present invention will be described in detail.
FIG. 2 is a diagram illustrating a configuration of the energization heating device according to the first embodiment of the present invention.

  The energization heating apparatus 10 is for energizing and heating the plated metal plate 11 when hot stamping the plated metal plate 11. In the following description, it is assumed that a plating layer is formed on the entire surface of the plated metal plate 11 (over the entire width direction) unless otherwise specified. The energization heating apparatus 10 includes first and second auxiliary energization cylinders 12 and 13. The plated metal plate 11 and the first and second auxiliary energizing cylinders 12 and 13 both have a longitudinal shape.

  The first auxiliary energization cylinder 12 includes four flat plate portions, that is, a first flat plate portion 12a, a pair of first side plate portions 12b, and a first top plate portion 12c. It is configured in a cylindrical shape. The shape of the cross section (cross section perpendicular to the longitudinal direction) of the first auxiliary energization cylinder 12 is a rectangle.

  The first flat plate portion 12a has the same planar shape as the plated metal plate 11 (in this embodiment, a rectangle). When the plated metal plate 11 is energized and heated, the first flat plate portion 12 a is opposed to the first surface (upper surface in FIG. 2) of the plated metal plate 11 and is disposed in parallel to the plated metal plate 11.

  Similarly, the second auxiliary energization cylinder 13 includes four flat plate portions, that is, a second flat plate portion 13a, a pair of second side plate portions 13b, and a second top plate portion 13c. As shown in FIG. The shape of the cross section (cross section perpendicular to the longitudinal direction) of the second auxiliary energizing cylinder 13 is a rectangle.

  The second flat plate portion 13 a has the same planar shape as the plated metal plate 11. During energization heating of the plated metal plate 11, the second flat plate portion 13 a faces the second surface (the lower surface in FIG. 2) of the plated metal plate 11 and is disposed in parallel to the plated metal plate 11.

  The electric heating device 10 includes a cooling device 16. The cooling device 16 allows a cooling medium (for example, water) to flow inside each of the first and second auxiliary energizing cylinders 12 and 13. The cooling medium exits from the cooling device 16, enters the inside from one end side with respect to each of the first and second auxiliary energization cylinders 12, 13, exits from the other end side, and returns to the cooling device 16.

  The plated metal plate 11 may be, for example, a steel plate having a surface plated with a low melting point metal (Al, Sn, etc.). These low-melting-point metals generate a liquid phase by heating during hot stamping. It is preferable that the 1st and 2nd auxiliary | assistant electricity supply cylinders 12 and 13 consist of a material excellent in thermal conductivity, for example, consist of copper or a copper alloy.

  Hereinafter, for each of the plated metal plate 11 and the first and second auxiliary current-carrying cylinders 12 and 13, the end on the same side in the longitudinal direction (the right side in FIG. 2) is referred to as the “first end” and the other side. The end (left side in FIG. 2) is referred to as a “second end”.

  At the first end of the plated metal plate 11, for example, the first end of the first auxiliary energizing cylinder 12 is located on the first surface side of the plated metal plate 11 via a spacer made of a nonmagnetic insulator. And the first end of the second auxiliary energizing cylinder 13 is aligned and overlapped on the second surface side of the plated metal plate 11. Similarly, at the second end of the plated metal plate 11, for example, a second end of the first auxiliary energizing cylinder 12 is provided on the first surface side of the plated metal plate 11 via a spacer made of a nonmagnetic insulator. The portions are overlapped and aligned, and the second end of the second auxiliary energization cylinder 13 is aligned and overlapped on the second surface side of the plated metal plate 11. The interval between the plated metal plate 11 and the first flat plate portion 12a is substantially equal to the interval between the plated metal plate 11 and the second flat plate portion 13a. It is preferable that each of the 1st and 2nd flat plate parts 12a and 13a and the plating metal plate 11 is arrange | positioned at intervals of 1 mm or more.

  The energization heating device 10 includes a power supply device including a power supply 15. The power supply 15 includes a first output terminal 15a and a second output terminal 15b. Between the first output terminal 15a and the second output terminal 15b, the plated metal plate 11 and the first and second auxiliary energization cylinders 12 and 13 are connected.

  The plated metal plate 11 and the first and second auxiliary energizing cylinders 12 and 13 are connected in series to the power source 15, and the first auxiliary energizing cylinder 12 and the second auxiliary energizing cylinder 13 are connected. Are connected in parallel. More specifically, the first output terminal 15 a of the power supply 15 is connected to the first end of the plated metal plate 11. The second end of the plated metal plate 11 is connected to the second end of each of the first and second auxiliary energizing cylinders 12 and 13. The first ends of the first and second auxiliary energization cylinders 12 and 13 are connected to the second output terminal 15 b of the power supply 15.

The power source 15 may be either one that applies a DC voltage or one that generates an AC voltage. In any case, when a voltage is applied between the first output terminal 15a and the second output terminal 15b of the power supply 15, a plated metal plate is always applied to each of the first and second auxiliary energizing cylinders 12 and 13. A current in the direction opposite to the current flowing in the current 11 flows. If the magnitude of the current flowing through the plated metal plate 11 is I ₁ , the magnitude I _{2 of the} current flowing through each of the first and second auxiliary energizing cylinders 12 and 13 is ½ × I ₁ . The Lorentz force generated in the plated metal plate 11 can be suppressed by the magnetic field formed by the current flowing through the first and second auxiliary energizing cylinders 12 and 13.

  The first and second auxiliary are generated by the magnetic field generated by energizing the plated metal plate 11 and the first and second auxiliary energization cylinders 12 and 13 and the current flowing through the first and second auxiliary energization cylinders 12 and 13. A Lorentz force in the out-of-plane direction, that is, the direction away from the plated metal plate 11 is applied to the current-carrying cylinders 12 and 13. However, since the first and second auxiliary energization cylinders 12 and 13 are cylindrical and have higher rigidity than the plate-like auxiliary energization member, the first and second auxiliary energization cylinders due to this Lorentz force are used. Deflection of the electric cylinders 12 and 13 is remarkably suppressed.

  Also, during the energization heating of the plated metal plate 11, the cooling device 16 causes the cooling medium to flow inside each of the first and second auxiliary energization cylinders 12, 13, thereby providing the first and second auxiliary energization cylinders. The temperature rise of 12 and 13 can be suppressed, and the reduction in rigidity can be suppressed. Also by this, the deflection of the first and second auxiliary energizing cylinders 12 and 13 can be suppressed.

  For this reason, the interval between the plated metal plate 11 and the first flat plate portion 12a and the interval between the plated metal plate 11 and the second flat plate portion 13a are maintained at substantially the set distances. Even if it is made smaller, the plated metal plate 11 and the first or second flat plate portions 12a and 13a are difficult to contact. Therefore, in the process of determining an appropriate energization heating condition that can reduce the Lorentz force as a whole for the same plated metal plate, the setting is more flexible than when an auxiliary energization plate is used instead of the auxiliary energization cylinder. The degree can be increased. For this reason, compared with the case where an auxiliary energizing plate is used, the Lorentz force with respect to the molten plating layer can be reduced, and the deviation of the plating layer can be reduced.

  FIG. 3 is a diagram showing a configuration of an energization heating apparatus according to the second embodiment of the present invention. 3, constituent elements corresponding to those shown in FIG. 2 are denoted by the same reference numerals as those in FIG.

  The energization heating device 30 includes a power source 35 having first and second terminals 35a and 35b as a pair of output terminals, and first and second circuits 37 and 38. The power source 35 may generate a DC voltage or an AC voltage. The first and second circuits 37 and 38 form a circuit that connects the plated metal plate 11, the first auxiliary energization cylinder 12, and the second auxiliary energization cylinder 13 in parallel to the power supply 35.

  The first circuit 37 includes a first output terminal 35 a of the power source 35, a first end of the plated metal plate 11, a second end of the first auxiliary energization cylinder 12, and a second of the second auxiliary energization cylinder 13. Electrically connect to the end. The first circuit 37 connects the first output terminal 35a of the power source 35 and the first end of the plated metal plate 11 and is provided with a conductive path provided with the first branch point P1, and the first auxiliary energizing cylinder 12 A conductive path connecting the two ends and the second end of the second auxiliary energization cylinder 13 and provided with the second branch point P2, and a conductive path connecting the first branch point P1 and the second branch point P2. Including.

  The second circuit 38 includes a second output terminal 35 b of the power source 35, a second end of the plated metal plate 11, a first end of the first auxiliary energization cylinder 12, and a first of the second auxiliary energization cylinder 13. Electrically connect to the end. The second circuit 38 connects the second output terminal 35b of the power source 35 and the second end of the plated metal plate 11 and has a conductive path provided with the third branch point P3, and the first auxiliary energizing cylinder 12 A conductive path connecting the first end and the first end of the second auxiliary energizing cylinder 13 to provide the fourth branch point P4, and a conductive path connecting the third branch point P3 and the fourth branch point P4 Including.

  In the conductive path between the first branch point P1 and the second branch point P2, and the conductive path between the third branch point P3 and the fourth branch point P4, the first variable resistors R11 and R12 are respectively It is intervened. The conductive path between the first branch point P1 and the first end of the plated metal plate 11 and the conductive path between the third branch point P3 and the second end of the plated metal plate 11 are second variable. Resistors R21 and R22 are respectively interposed.

When the resistance value of at least one of the first variable resistor R11 and the first variable resistor R12 is increased, the magnitude I _{2 of the} current flowing through each of the first and second auxiliary energizing cylinders 12 and 13 is decreased. When the resistance value of at least one of the second variable resistor R21 and the second variable resistor R22 is increased, the magnitude I _{1 of the} current flowing through the plated metal plate 11 is decreased. That is, by adjusting the resistance values of the first variable resistors R11 and R12 and the second variable resistors R21 and R22 (including the case where the resistance value of any of the variable resistors is zero), these currents are obtained. The magnitudes I ₁ and I ₂ can be adjusted.

In this embodiment, each of the first and second auxiliary energization cylinders 12 and 13 is used regardless of whether the power source 35 generates a DC voltage or an AC voltage. The direction of the flowing current is always opposite to the direction of the current flowing through the plated metal plate 11. In addition, by appropriately adjusting the resistance values of the first variable resistors R11, R12 and the second variable resistors R21, R22, the magnitude of the current flowing through each of the first and second auxiliary energizing cylinders 12, 13 is adjusted. The thickness I ₂ can be made larger than ½ of the magnitude I ₁ of the current flowing through the plated metal plate 11.

In this case, as compared with the case where I ₂ = 1/2 × I ₁ by appropriately adjusting the magnitude I _{2 of the} current flowing through each of the first and second auxiliary energization cylinders 12 and 13, Lorentz force generated in the plated metal plate 11 can be reduced. Thereby, even if a plating layer melts by energizing and heating the plated metal plate 11, the Lorentz force acting on the melt can be suppressed, and the movement of the melt can be suppressed. Accordingly, the energization heating using the energization heating device 30 can suppress the deviation of the plating layer as compared with the case where the energization heating device 10 of FIG. 2 is used.

The Lorentz force acting on the melt generated by energization heating of the plated metal plate 11 varies depending on, for example, the following parameters.
(i) The interval between the plated metal plate 11 and the first auxiliary energizing cylinder 12 and the interval between the plated metal plate 11 and the second auxiliary energizing cylinder 13
(ii) Plated metal plate 11 and the thickness of each of first and second auxiliary energizing cylinders 12 and 13
(iii) Material of the first and second auxiliary energizing cylinders 12 and 13

In accordance with such parameters, the magnitude I _{1 of the} current flowing through the plated metal plate 11 and the current flowing through the first and second auxiliary energizing cylinders 12 and 13 so that the Lorentz force is minimized for the entire melt. It is preferable to optimize the magnitude I ₂ of the. By adjusting the resistance values of the first variable resistors R11 and R12 and the second variable resistors R21 and R22, such optimum current magnitudes I ₁ and I ₂ can be realized.

  The energization heating device 30 causes the cooling medium to flow inside each of the first and second auxiliary energization cylinders 12 and 13 by the same cooling device as the cooling device 16 provided in the energization heating device 10 shown in FIG. It may be configured. Thereby, the temperature rise of the 1st and 2nd auxiliary | assistant electricity supply cylinders 12 and 13 can be suppressed, the fall of rigidity can be suppressed, and the bending of the 1st and 2nd auxiliary electricity supply cylinders 12 and 13 can be suppressed.

One of the first variable resistor R11 of the first circuit 37 and the first variable resistor R12 of the second circuit 38 may not be provided. Even in this case, the magnitude I _{2 of the} current flowing through the first and second auxiliary energizing cylinders 12 and 13 by the first variable resistor R11 of the first circuit 37 or the first variable resistor R12 of the second circuit 38 is also shown. Can be adjusted. Similarly, one of the second variable resistor R21 of the first circuit 37 and the second variable resistor R22 of the second circuit 38 may not be provided. Even in this case, the magnitude I _{1 of the} current flowing through the plated metal plate 11 can be adjusted by the second variable resistor R21 of the first circuit 37 or the second variable resistor R22 of the second circuit 38.

Furthermore, when a current having an appropriate magnitude I ₂ flows through the first and second auxiliary energizing cylinders 12 and 13, the first variable resistors R11 and R12 may not be provided. Similarly, when a current having an appropriate magnitude I ₁ flows through the plated metal plate 11, the second variable resistors R21 and R22 may not be provided. Furthermore, when a current having an appropriate magnitude I ₂ flows through the first and second auxiliary energization cylinders 12 and 13 and a current having an appropriate magnitude I ₁ flows through the plated metal plate 11, the first variable resistor None of R11, R12 and the second variable resistors R21, R22 may be provided. For example, when the resistance values of the first and second auxiliary energization cylinders 12 and 13 and the output voltage of the power source 35 are appropriately selected, the first and second auxiliary energization cylinders 12 and 13 are appropriately large. It is possible to realize a state in which a current I ₂ flows and an appropriate current I ₁ flows through the plated metal plate 11.

In this embodiment, when it is not necessary to change the ratio of the magnitude I ₂ of the current flowing through each of the first and second auxiliary energizing cylinders 12 and 13 to the magnitude I ₁ of the current flowing through the plated metal plate 11 May use fixed resistors in place of the first variable resistors R11 and R12 and the second variable resistors R21 and R22.

  In each of the above embodiments, the plated layer is formed on the entire surface of the plated metal plate 11, but the plated layer may be formed on a part of the plated metal plate 11 in the width direction. In the above embodiment, each of the first and second flat plate portions 12a and 13a has the same planar shape as the plated metal plate 11, but both the first and second flat plate portions are plated metal plate 11. And does not necessarily have the same planar shape. Furthermore, the cross-sectional shapes of the first and second auxiliary energization cylinders 12 and 13 are all rectangular in the above embodiment, but may be shapes other than the rectangle.

  FIG. 4A is a cross-sectional view showing a first auxiliary current-carrying cylinder provided in an electric heating device according to a third embodiment of the present invention, together with a plated metal plate to be heated.

  On the first and second surfaces of the plated metal plate 11 having a width W, a plating layer 11P having a width Wx smaller than W is formed. That is, the plating layer 11 </ b> P is formed on a part of the plated metal plate 11 in the width direction. The plating layer 11P on the first surface and the plating layer 11P on the second surface are formed at the same position in the width direction and the length direction of the plated metal plate 11. The center in the width direction of the plating layer 11P and the center in the width direction of the plated metal plate 11 may or may not match.

  12 A of 1st auxiliary | assistant electricity supply cylinders have 1st flat plate part 12Aa. The width of the first flat plate portion 12Aa is We, and satisfies 0.95 × Wx ≦ We. That is, the first flat plate portion 12 </ b> Aa may have a planar shape different from the plated metal plate 11. In the first auxiliary energizing cylinder 12A, the portions other than the first flat plate portion 12Aa have an indefinite shape (in this embodiment, a mountain shape). The first flat plate portion 12Aa is arranged in parallel with the plated metal plate 11 so that the center in the width direction of the first flat plate portion 12Aa and the center in the width direction of the plated layer 11P are aligned. Is done. The second auxiliary energization cylinder (not shown in FIG. 4A) has a symmetrical shape with respect to the plated metal plate 11, and is disposed at a symmetrical position with respect to the plated metal plate 11.

  Even in the electric heating apparatus of this embodiment, by satisfying 0.95 × Wx ≦ We, even when the width We of the first and second flat plate portions 12Aa and 12Ab is smaller than the width Wx of the plating layer 11P, The first and second flat plate portions 12Aa and 12Ab face almost the entire region. For this reason, if a current of an appropriate magnitude is supplied to the first and second auxiliary energization cylinders, the Lorentz force that can act on the molten plating layer can be suppressed. Further, when the plated metal plate is energized and heated, the first and second auxiliary energization cylinders are less likely to bend than the plate-like auxiliary energization member. Further, the cooling medium can flow through the first and second auxiliary energization cylinders, and in this case, the deflection of the first and second auxiliary energization cylinders can be further suppressed.

  FIG. 4B is a cross-sectional view showing the first auxiliary energization cylinder provided in the energization heating apparatus according to the fourth embodiment of the present invention, together with the plated metal plate to be heated. In FIG. 4B, constituent elements corresponding to those shown in FIG. 4A are assigned the same reference numerals as in FIG.

  In this embodiment, the cross-sectional shape of the first auxiliary energizing cylinder 12B is symmetric with respect to the perpendicular bisector of the first flat plate portion 12Ba. Similarly, the cross-sectional shape of the second auxiliary energizing cylinder (not shown in FIG. 4B) is symmetric with respect to the vertical bisector of the second flat plate portion. Thereby, as compared with the third embodiment, the Lorentz force due to the current flowing in the first and second auxiliary energization cylinders becomes uniform, and the effect of suppressing the shift of the plating layer is easily obtained.

  FIG. 4C is a cross-sectional view showing the first auxiliary energization cylinder provided in the energization heating apparatus according to the fifth embodiment of the present invention, together with the plated metal plate to be heated. In FIG. 4C, components corresponding to the components shown in FIG. 4A are assigned the same reference numerals as in FIG. 4A, and description thereof is omitted.

  In this embodiment, the cross-sectional shape of the first auxiliary energizing cylinder 12C is a rectangle, and is symmetric with respect to the perpendicular bisector of the first flat plate portion 12Ca. Therefore, in the first auxiliary energization cylinder 12 </ b> C, not only the first flat plate portion 12 </ b> Ca but also the flat plate portion opposite to the first flat plate portion 12 </ b> Ca is parallel to the plated metal plate 11. Similarly, the cross-sectional shape of the second auxiliary energizing cylinder (not shown) is a rectangle and is symmetric with respect to the vertical bisector of the second flat plate portion. Therefore, in the second auxiliary energizing cylinder, not only the second flat plate portion but also the flat plate portion on the opposite side to the second flat plate portion is parallel to the plated metal plate 11. Thereby, as compared with the fourth embodiment, the Lorentz force due to the current flowing in the first and second auxiliary energization cylinders becomes more uniform, and the effect of suppressing the shift of the plating layer is further easily obtained. .

  In the energization heating device of the present invention, the cross-sectional shape of the first and second auxiliary energization cylinders may be other than the above, for example, a triangle, a trapezoid, or an inverted trapezoid.

  In order to confirm the effect of the present invention, an auxiliary energizing member (auxiliary energizing plate and auxiliary energizing cylinder) is obtained by numerical analysis (simulation) for each of the conventional energizing heating apparatus and the energizing heating apparatus of the present invention. Body) was determined.

  FIG. 5 is a cross-sectional view showing the configuration of an electric heating apparatus according to the present invention and a conventional electric heating apparatus as a comparative example. The conventional energization heating apparatus has the configuration shown in FIGS. 1A and 1B, and includes auxiliary power supply plates 4A and 4B having a flat plate shape as auxiliary power supply members. The energization heating apparatus of the present invention has the configuration shown in FIG. 2 and includes auxiliary energization cylinders 12 and 13 having a rectangular cross section as auxiliary energization members.

  The thicknesses of the auxiliary energizing plates 4A and 4B and the total thickness of the auxiliary energizing cylinders 12 and 13 (the distance between the surface facing the plated metal plate 11 and the surface opposite thereto) were all 10 mm. The thickness of each plate part constituting the auxiliary energizing cylinders 12 and 13 was 3 mm. The thickness of the plated metal plate 11 to be electrically heated was 1.6 mm. Each of the plated metal plate 11, the auxiliary energizing plates 4A and 4B, and the auxiliary energizing cylinders 12 and 13 had a width of 200 mm and a length of 1000 mm.

  The plated metal plate 11 was energized and heated to 870 ° C. at a heating rate of 85 ° C./s. At this time, an electric current in the opposite direction (reverse phase) to the plated metal plate 11 is passed through the auxiliary energizing plates 4A and 4B or the auxiliary energizing cylinders 12 and 13, and the Lorentz acting on the plated portion of the plated metal plate 11 thereby. The effect of suppressing the force Fx was verified.

In the present invention example, cooling water of 20 ° C. is passed through the auxiliary energizing cylinders 12 and 13, and the inner surfaces of the auxiliary energizing cylinders 12 and 13 are forcibly cooled with a heat transfer coefficient of 10,000 W / m ² / K. It was supposed to be. When the distance d between the plated metal plate 11 and the auxiliary energizing member is 10 mm, the Lorentz force Fx acting on the surface of the plated metal plate 11, the maximum temperature of the auxiliary energizing member, and the maximum deflection amount of the auxiliary energizing member are numerical values Calculated by analysis.

  Table 1 shows the results of numerical analysis. In the example of the present invention, the Lorentz force Fx (the amount of deflection) acting on the surface of the plated metal plate 11 is not considered while suppressing the increase in the temperature of the auxiliary energization member and reducing the deflection of the auxiliary energization member, compared to the comparative example. It can be seen that the effect of suppressing the above can be made equal to or less than that of the comparative example. Since the deflection amount is larger than that of the present invention example in the comparative example, the Lorentz force acting on the plated metal plate during actual energization heating is larger in the comparative example, and the deviation of the plating layer may be increased. is expected.

10, 30: Current heating device, 11: Plated metal plate for hot stamping,
11P: plating layer, 12, 12A, 12B, 12C: first auxiliary energization cylinder,
12a, 12Aa, 12Ba, 12Ca: first flat plate portion,
13: 2nd auxiliary energization cylinder, 13a: 2nd flat plate part, 16: Cooling device

Claims (9)

An energization heating device that energizes and heats a plated metal plate for hot stamping having first and second ends,
A first auxiliary current-carrying cylinder having first and second end portions arranged in alignment with the first and second end portions of the plated metal plate, respectively;
A second auxiliary current-carrying cylinder having first and second ends that are arranged in alignment with the first and second ends of the plated metal plate, respectively.
The first and second end portions of the plated metal plate and the first and second end portions of the first and second auxiliary current-carrying cylinders are connected to flow current to the plated metal plate, and the first Each of the first and second auxiliary energization cylinders is provided with a power supply device for flowing a current in a direction opposite to the current flowing in the plated metal plate,
A plating layer having a width Wx (0 <Wx ≦ W) with respect to a width W of the plated metal plate is formed on the plated metal plate;
The first auxiliary energization cylinder includes a first flat plate portion having a width of 0.95 × Wx or more, and the first flat plate portion has a width direction center of the first flat plate portion and a width direction of the plating layer. Are aligned with the center of the metal plate and opposed to the first surface of the plated metal plate,
The second auxiliary energization cylinder includes a second flat plate portion having a width of 0.95 × Wx or more, and the second flat plate portion has a width direction center of the second flat plate portion and a width direction of the plating layer. An electric heating apparatus for a hot stamping plated metal plate, the center of which is aligned with the second surface of the plated metal plate. It is an electricity heating apparatus of Claim 1, Comprising:
The energization heating apparatus in which the plating layer is formed over the entire width direction of the plated metal plate. It is an electricity heating apparatus of Claim 2, Comprising:
Each of the said 1st and 2nd flat plate part is an electricity heating apparatus which has the same planar shape as the said plated metal plate. It is an electricity heating apparatus in any one of Claims 1-3,
A cross-sectional shape of the first auxiliary energization cylinder is symmetric with respect to a perpendicular bisector of the first flat plate portion;
The energization heating apparatus, wherein a cross-sectional shape of the second auxiliary energization cylinder is symmetric with respect to a perpendicular bisector of the second flat plate portion. It is an electricity heating apparatus in any one of Claims 1-3,
An energization heating apparatus in which each of the first and second auxiliary energization cylinders has a rectangular cross-sectional shape. It is an electricity heating apparatus in any one of Claims 1-5,
An energization heating device further comprising a cooling device that causes a cooling medium to flow inside the first and second auxiliary energization cylinders. It is an electricity heating apparatus in any one of Claims 1-6,
An energization heating apparatus, wherein the plated metal plate is a plated steel plate for hot stamping. It is an electricity heating apparatus in any one of Claims 1-7,
An energization heating apparatus in which the first and second auxiliary energization cylinders are made of copper or a copper alloy. It is an electricity heating apparatus in any one of Claims 1-8,
Each of the said 1st and 2nd flat plate part and the said plated metal plate are the electrical heating apparatuses arrange | positioned at intervals of 1 mm or more.

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