JP2009142854A - Electric heating device, hot press forming device having the same, and electric heating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric heating device which can feed an electric heated workpiece stably to the processes after the electric heating while preventing distortion of the workpiece due to electric heating as much as possible, and also to provide a hot press forming device having the heating device and an electric heating method. <P>SOLUTION: In the electric heating device 3 for electric heating the workpiece W to be hot press formed while clamping by a clamp mechanism (30, 31, etc.) and applying tension, the clamp mechanism (30, 31, etc.) comprises a fixed clamp member 30 and a movable clamp member 31, an elevating/lowering cylinder 32 for the fixed clamp member 30 and the movable clamp member 31, and tensioning cylinders 33a, 33b for driving the movable clamp member 31 along the plane direction of the workpiece W. During the electric heating, the fixed clamp member 30 holds the workpiece W with clamping the one side thereof at a fixed position, and the movable clamp member 31 moves while holding the other side of the workpiece W as the workpiece W thermally deforms. Thus, tension is applied to the workpiece W depending on thermal deformation of the workpiece W. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric heating apparatus, a hot press forming apparatus having the electric heating apparatus, and an electric heating method, and more particularly to an electric heating apparatus incorporated in the hot press forming apparatus and an electric heating method executed by the hot press forming apparatus.

  As one of the methods for mass-producing vehicle parts that require high strength, a hot press forming method or a die quench method is adopted. The die quench method is a method in which a steel sheet is heated to about 900 ° C., and then rapidly cooled simultaneously with press forming to quench the formed product. Conventionally, a continuous heating furnace installed separately from the press forming apparatus has been generally used for heating the steel sheet.

  On the other hand, Patent Document 1 discloses a hot press forming method using an electric heating mechanism for heating a steel plate. Specifically, Patent Document 1 states that “in the mold or in the vicinity of the mold outside the mold, one or more electrodes are attached to both ends of the metal plate, and a current is applied between the electrodes, so that Joule heat is applied. The metal plate is heated to a predetermined processing temperature, followed by hot press forming. ”A method for hot press forming a metal plate is disclosed.

  The energization heating mechanism of Patent Document 1 has a pair of left and right clamp electrodes that move along the longitudinal direction of the workpiece, and the pair of left and right clamp electrodes clamps both ends in the longitudinal direction of the workpiece during energization heating, A tensile force is applied to the workpiece in both the left and right directions along the longitudinal direction of the workpiece. Both of the pair of left and right clamp electrodes are stopped during energization heating, and the clamp interval between the pair of left and right clamps is fixed.

Japanese Patent Laid-Open No. 2002-18531

  According to the energization heating mechanism of Patent Document 1, there is a problem that the workpiece is greatly distorted, particularly the center portion of the workpiece hangs down even when a tensile force is applied to the workpiece during energization heating.

  The reason is that the clamp interval by the pair of left and right clamps is fixed at the time of energization heating, even though the workpiece expands as the temperature rises. In other words, since both ends of the work are restrained at fixed positions during energization heating, the center of the work, which is easily thermally deformed due to temperature rise, hangs down due to its own weight.

  For this reason, according to the electric heating mechanism of patent document 1, it is difficult to stably supply a work to the downstream process of electric heating. The reason for this is that the distortion of the workpiece due to energization heating is large, so that the positioning of the workpiece becomes difficult, and the greatly distorted portion may interfere with the holder of the transport mechanism and the mold of the hot press mechanism.

  The present invention is capable of preventing distortion of a work due to current heating as much as possible, and capable of stably supplying a current-heated work to a downstream process of current heating and a hot press having the same. It is an object of the present invention to provide a molding apparatus and an electric heating method.

  The present invention provides, in a first aspect, an energization heating apparatus that energizes and heats a workpiece that is hot press-molded by a clamp mechanism and applies a tension while the clamp mechanism is on one side of the workpiece. Can clamp one side of the workpiece and can hold the other side of the workpiece by clamping the other side of the workpiece and a fixed clamp member that can be fixed or fixed in position along a predetermined direction. A movable clamp member that is movable along the predetermined direction, and during energization heating, the fixed clamp member holds one side of the workpiece at a fixed position, and the movable clamp member A tension is applied to the workpiece by moving along the predetermined direction while holding the other side of the workpiece with thermal deformation along the predetermined direction. Providing heat device. The predetermined direction is a main direction in which the workpiece is easily stretched due to thermal deformation, and is, for example, the same direction as the longitudinal direction of the workpiece and the direction along the upper and lower surfaces or the press surface of the workpiece.

  According to a second aspect of the present invention, there is provided an energization heating apparatus that clamps a workpiece that is hot press-molded by a clamp mechanism and energizes and heats the workpiece while applying a tension, and the clamp mechanism clamps the workpiece differently. A first and second clamp members that clamp at a position and apply tension to the workpiece; a clamp direction drive mechanism that drives the first and second clamp members to clamp the workpiece; There is provided an energization heating device having a clamp interval variable mechanism that varies a clamp interval by the first and second clamp members in accordance with thermal deformation of the workpiece.

  In a third aspect, the present invention provides a hot press forming apparatus having the energization heating apparatus according to the present invention and a hot press mechanism for hot press forming the workpiece heated by the energization heating apparatus. .

  According to a fourth aspect of the present invention, there is provided an energization heating method in which a workpiece to be hot press-molded is clamped and energized and heated while applying a tension, wherein one side and the other side of the workpiece are respectively clamped and In the clamping step of applying tension while holding the workpiece, the energizing heating step of energizing and heating the clamped workpiece, and clamping the one side of the workpiece at a fixed position, There is provided an energization heating method including a tension applying step at the time of energization heating in which a tension is applied to the work by moving a position at which the other side is clamped together with the work to be thermally deformed.

  According to the present invention, during energization heating, depending on the thermal deformation of the workpiece, in particular, thermal expansion or extension, the clamping position or the clamp interval holding the workpiece is preferably set according to the thermal deformation amount together with the workpiece to be thermally deformed. Move or change. As a result, an appropriate tension is applied to the workpiece during energization heating, and distortion of the workpiece due to temperature rise is suppressed. In particular, the central portion of the workpiece is suppressed from drooping greatly, and the workpiece is made as flat as possible. State is maintained. As a result, in the case where the energized and heated work is transported to the downstream hot press mechanism, interference between the work and the components of the transport mechanism or the hot press mechanism is prevented.

  According to the present invention, one side of the workpiece is clamped at a fixed position by the fixed clamp member during energization heating. This prevents the workpiece positioning position from being shifted due to thermal deformation of the workpiece or movement of the movable clamp member. As a result, when a work that has been energized and heated is transported to a downstream hot press mechanism, it is easy to deliver the work to the transport mechanism or the hot press mechanism, and the work positioning is facilitated in the hot press forming process. . That is, stable supply of the workpiece heated by energization is achieved.

  Thus, the present invention can stably supply an electrically heated workpiece to a downstream process, and thus contributes to hot press molding, in particular, high cycle die quenching. Further, when the clamp is an electrode combined clamp, as described above, according to the present invention, the work is kept as flat as possible during energization heating, so that uniform heating of the work is expected.

  According to a preferred embodiment of the present invention, the clamp mechanism is an elevating direction driving mechanism that clamps the work by driving the fixed clamp member and the movable clamp member to move up and down along the thickness direction of the work. And a movable clamp member driving mechanism for driving the movable clamp member so as to be movable along the predetermined direction.

  According to a preferred embodiment of the present invention, each of the fixed clamp member and the movable clamp member includes a pair of upper and lower clamps that face each other in the thickness direction of the workpiece and can sandwich the workpiece. According to this embodiment, the workpiece clamp is stable and it is easy to secure the moving stroke of the movable clamp member.

  According to a preferred embodiment of the present invention, of the pair of upper and lower clamps respectively provided in the fixed clamp member and the movable clamp member, the lower clamps separated from each other along the predetermined direction or the longitudinal direction of the workpiece. Is a pair of electrodes for energizing the workpiece. According to this embodiment, power saving, mechanism saving, and uniform heating of the workpiece are expected.

  According to a preferred embodiment of the present invention, each of the fixed clamp member and the movable clamp member includes a pair of upper and lower clamps that are opposed to each other along the thickness direction of the workpiece and can sandwich the workpiece. The portion of the upper clamp that holds the workpiece is a convex curved surface, and the portion of the lower clamp that holds the workpiece is planar. According to this form, the clamp is stabilized. In addition, when the clamp also serves as an electrode, it is possible to prevent the electrode from being struck against the workpiece and to prevent local overheating of the workpiece.

  According to a preferred embodiment of the present invention, there is provided a sag prevention member that is disposed below the center portion of the workpiece during energization heating and is capable of supporting the center portion. Further preferably, the drooping prevention member is a plurality of pins erected along the vertical direction. According to such a form, it is possible to prevent or suppress the drooping of the center portion of the workpiece during energization heating without hindering the supply of the workpiece to the energization heating device or the removal thereof downstream.

  According to a preferred embodiment of the present invention, the clamp mechanism includes a clamp for elastically clamping the workpiece or an electrode combined clamp. More preferably, the clamp mechanism includes a support member or a support column to which the clamp or the electrode combined clamp is attached, and the support member is directly or indirectly connected to the base and the clamp. Or, it is inserted directly or indirectly between the base and the mounting portion so that an elastic force is applied along the clamping direction between the mounting portion to which the electrode combined clamp is mounted and the base and the mounting portion. An elastic portion. According to this embodiment, the contact area between the clamp and the workpiece increases, and a uniform clamping load acts on the workpiece, so that the clamp is stabilized, and the contact area between the electrode and the workpiece increases, thereby causing local overheating of the workpiece. Is prevented.

  In the embodiment of the present invention, it is sufficient to heat the work by heating to a temperature at which hot pressing is possible. For example, when the workpiece is a steel material, the heating may be performed between the A1 transformation point and the liquid phase precipitation point, for example, between 850 and 1200 ° C.

  The present invention is suitably applied to heating and further heat forming of workpieces of various materials capable of energization heating and hot working, particularly die quenching, for example, for forming various metal materials such as steel and aluminum. Applied. The present invention is also suitably applied to heating of hot-formed steel sheets (for example, galvanized steel sheets, alloyed hot-dip galvanized steel sheets, aluminum-plated steel sheets) in addition to general steel sheets.

  An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an external view of a hot press forming apparatus in which an electric heating apparatus according to an embodiment of the present invention is incorporated.

  Referring to FIG. 1, in this hot press forming apparatus 1, an electric heating device 3 in which workpieces are supplied one by one from a robot-type charging mechanism 2 into the device 1, and heat is supplied downstream of the electric heating device 3. The die-quenching hot press mechanism 4 disposed at a distance from the hot press mechanism 4 and at least the work heated by the hot press mechanism 4 from the energization heating device 3 to the hot press mechanism 4 and from the hot press mechanism 4 to the take-out position. And a transfer mechanism 5 for conveying the molded product. Note that the hot press molding apparatus 1 is provided with a conveyor 7 for taking out a molded product or a finished product from the dispensing position of the apparatus 1.

  The workpiece input mechanism 2 is a robot mechanism that takes out one by one from a magazine in which a plurality of workpieces or blanks are housed, and supplies the workpieces to the energization heating device 3 one by one.

  The energization heating device 3 clamps and releases the clamped workpiece, energizes the workpiece to which the tension by the clamp is applied, and heats the workpiece.

  The hot press mechanism 4 forms a molded product from the workpiece by hot pressing and rapidly cooling the heated workpiece.

  The transfer mechanism 5 is a hot-press forming apparatus 1 or an energizing / heating apparatus 3 at which a workpiece is charged, an energizing position at which the energizing / heating apparatus 3 energizes the work, and a hot-pressing mechanism 4 hot-presses the work. A work position and a discharge position at which the molded product is discharged from the hot press molding apparatus 1, and holds or releases the workpiece or the molded product, and the loading position and the energized position, the energized position and the processed position, And a plurality of holding mechanisms or holding tools that reciprocate between the machining position and the payout position.

  2 (A) to 2 (C) are three views for explaining the mechanical structure of the energization heating apparatus or hot press forming apparatus shown in FIG. 1, and FIG. 2 (A) is a top view. 2B is a front view, and FIG. 2C is a side view. FIG. 3 is an enlarged view of FIG. 2C shows a state in which the upper clamps 30a and 31a are in the raised position and the movable clamp member 31 has moved to the end.

  Referring to FIGS. 2A to 2C and FIG. 3, in the hot press molding apparatus 1, an insertion position P0 where workpieces W are introduced in order from upstream to downstream along the transport direction. An energization position P1 where energization heating is performed by the energization heating device 3, a processing position P2 where hot press molding or die quenching is performed by the hot press mechanism 4, a delivery position P3 where the molded product is dispensed from the hot press molding device 1, etc. The pitch is set.

  The energization heating device 3 includes a clamp mechanism (30, 31, 32, 33a, 33b, 34) to be described later, an electrode that contacts the workpiece W, a wiring that electrically connects the electrode and the power supply, and an energization switch. An energization mechanism (see energization mechanism 37 in FIG. 4) and a drooping prevention member that is disposed below the center portion of the workpiece W that is energized and heated, is erected along the vertical direction, and can support the center portion of the workpiece W. A plurality of pins 35.

  The clamp mechanism (30, 31, 32, 33a, 33b, 34) includes a fixed clamp member 30 and a movable clamp member 31 (first and second clamp members), and an ascending / descending direction of the fixed clamp member 30 and the movable clamp member 31. Lifting cylinder 32 that is a drive mechanism or a clamp direction drive mechanism, and a movable clamp member drive mechanism that moves the movable clamp member 31 along the predetermined direction, or a clamp interval variable mechanism that is a variable clamp interval according to the thermal deformation of the workpiece W. Tension cylinders 33a and 33b and upper and lower linear motion guides 34 and 34 for guiding the movement of the movable clamp member 31 are provided.

  The fixed clamp member 30 clamps one side of the workpiece W at a fixed position along the longitudinal direction or the left-right direction of the workpiece W and can hold the same side, and also has a function of positioning the workpiece W. The movable clamp member 31 clamps the other side of the work W and can hold the other side and can move along the predetermined direction or the left-right direction. During energization heating, the fixed clamp member 30 holds one side of the workpiece at a fixed position, while the movable clamp member 31 moves while holding the other side of the workpiece W as the workpiece W is thermally deformed. With such a fixed clamp member 30 and a movable clamp member 31, a tension is applied to the workpiece W so as to prevent the drooping of the central portion of the workpiece W as much as possible during energization heating. A tension is applied that acts forward in the direction of movement.

  Each of the fixed clamp member 30 and the movable clamp member 31 includes a pair of upper and lower clamps 30 a, 30 b, 31 a, and 31 b that can oppose each other along the thickness direction of the workpiece W and can sandwich the workpiece W. Of the pair of upper and lower clamps 30 a, 30 b, 31 a, 31 b respectively provided in the fixed clamp member 30 and the movable clamp member 31, the pair of lower clamps 30 b, 31 b that are separated from each other along the longitudinal direction of the workpiece W are attached to the workpiece W. A pair of electrodes for energization.

  The lift cylinder 32 clamps and holds the workpiece W by driving the upper clamps 30a and 31a of the fixed clamp member 30 and the movable clamp member 31 so as to move up and down along the thickness direction of the workpiece W. The upper and lower tension cylinders 33a and 33b drive the movable clamp member 31 movably along the predetermined direction, that is, the longitudinal direction or the left-right direction of the workpiece W. The upper and lower tension cylinders 33a and 33b exert a biasing force on the movable clamp member 31 so that the movable clamp member 31 does not slip with respect to the workpiece W when the movable clamp member 31 is moved during energization heating. The fixed clamp member 30 is provided in a fixed position along the predetermined direction, or is provided so that its initial position can be varied according to the shape of the workpiece W by an air cylinder, a motor, or the like.

  The clamps 30a, 30b, 31a, 31b are attached to the ends of the upper and lower support columns 39a, 39b, respectively. The upper support columns 39 a and 39 a are attached to an upper frame 38 a that can be raised and lowered, and the upper frame 38 a is connected to the raising and lowering cylinder 32. The lower support columns 39b and 39b are attached to a stationary lower frame 38b. Upper and lower linear motion guides 34 and 34 and tension cylinders 33a and 33b are arranged on the upper and lower frames 38a and 38b, respectively. The upper and lower clamps 31a and 31b of the movable clamp member 31 can be driven by a single cylinder or the like.

  The hot press mechanism 4 includes a cooling die 41 that hot-presses and rapidly cools the workpiece W conveyed from the energization position P1 by the transfer mechanism 5 after the workpiece W is energized and heated at the energization position P1. I have.

  The transfer mechanism 5 includes a pair of parallel arms 51 extending along the conveyance direction of the workpiece W, a pair of parallel arms 51, a width perpendicular to the conveyance direction, the elevation direction perpendicular to the conveyance direction, and the conveyance and elevation directions. A plurality of cylinders (not shown), which are driving means for reciprocatingly driving along a direction, and a pair of parallel arms 51 are attached to the pair of parallel arms 51 at predetermined intervals along the transport direction, and the pair of parallel arms 51 extends along the width direction. And a plurality of clamps (not shown) which are holding mechanisms or holding tools for holding the workpiece W or the molded product when approaching and releasing the holding when separating the workpiece W or the molded product. The plurality of clamps are arranged on the pair of parallel arms 51 at an equal pitch corresponding to the intervals between the input position P0, the energization position P1, the machining position P2, and the payout position P3. Note that a servo motor or the like can be employed as the drive means in place of the cylinder as the drive means.

  Furthermore, the transfer mechanism 5 has a support rod 54 that supports or guides the workpiece W that is thermally deformed so that the central portion hangs down by energization heating between the energization position P1 and the machining position P2. The support bar 54 is highly inclined toward the downstream side in the transport direction so that the processing position P2 side is higher than the energization position P1 side. The inclination angle of the support bar 54 is set in accordance with the material of the workpiece W, the heating temperature, and the stroke width of the transfer mechanism 5 in the vertical direction.

  FIG. 4 is a block diagram for explaining a control configuration of the energization heating device 3 shown in FIG. 3. Referring to FIG. 4, the electric heating device 3 includes a fixed clamp member 30 and a movable clamp member 31 (first and second clamp members), a lifting cylinder 32, upper and lower tension cylinders 33a and 33b, and a workpiece. A current sensor 36a for detecting the amount of current passed through W, a temperature sensor 36b for detecting the temperature of the workpiece, a position sensor 36c for moving up and down for detecting the positions of the fixed clamp member 30 and the movable clamp member 31 in the up and down direction, and movable A movable clamp member position sensor 36d that detects the position of the clamp member 31 in the moving direction, an energization mechanism 37 that controls energization of the workpiece W, the lifting cylinder 32 based on information detected by the sensors 36a to 36d, A control panel (microcomputer) that controls the tension cylinders 33a and 33b and the energization switch 37a. Has provided data) and 36e, the. The energization mechanism 37 is connected between the pair of lower clamps 30b and 31b, which are also used as electrodes, and a DC or AC power source P, and between the DC or AC power source P and the lower clamps 30b and 31b. The switch 37a includes the current sensor 36a and the temperature sensor 36b.

  Next, the operation of the energization heating device 3 will be described. FIGS. 5A to 5F are process diagrams for explaining the operation of the energization heating apparatus according to the embodiment of the present invention shown in FIGS. 5A to 5F, illustration of the upper and lower support pillars is omitted, and in FIG. 5E, illustration of the upper and lower frames is omitted. FIG. 5F is a top view of FIG. FIG. 6 is a process diagram for explaining the problem of the energization heating device with a fixed clamp interval L according to the comparative example.

[Clamping process]
5A to 5B, the workpiece W is held by a holder 53 of a pair of parallel arms 51 provided in the transfer mechanism 5, and is shown in FIG. 2A by a cylinder 52a. It is conveyed to the energization position P1 of the energization heating device 3 and placed on the pair of lower clamps 30b and 31b. Subsequently, the pair of parallel arms 51 are separated from each other by the cylinder 52c and then lifted by the cylinder 52b. Thus, the workpiece W is transferred to the energization heating device 3 side.

  Referring to FIGS. 5C to 5D, the fixed clamp member 30 and the upper clamps 30a and 31a of the movable clamp member 31 in the raised position are moved down by the lift cylinder 32, whereby the fixed clamp member 30 is fixed. On the member 30 side, one side of the workpiece W is clamped and held at a fixed position by the pair of upper and lower clamps 30a and 30b, thereby positioning the workpiece W. On the other hand, on the movable clamp member 31 side, the pair of upper and lower clamps The other side of the work is clamped and held by 31a and 31b. The initial clamping interval is set to “L”.

  In addition, you may connect another cylinder which sets or hold | maintains the initial position of a pair of upper and lower clamps 30a and 30b of the fixed clamp member 30 to a pair of upper and lower support pillars 39a and 39b, respectively. Instead of these cylinders, a positionable servo motor or the like can be employed.

[Electric heating process]
The lower clamps 30b and 31b spaced apart in the longitudinal direction of the workpiece W also serve as electrodes, and energization of the workpiece W is started via the pair of lower clamps 30b and 31b. The portions where the upper clamps 30a and 31a clamp the workpiece W are formed in a convex curved shape, and the portions where the lower clamps 30b and 31b clamp the workpiece W are formed in a flat shape, thereby improving the clamping performance. In addition, uniform heating is expected.

  Further, the upper and lower clamps 30a, 30b, 31a, 31b use bar-shaped clamps or bar-shaped electrodes having a sufficient length along the width direction of the workpiece W or the conveyance direction of the workpiece. And uniform heating is expected. The widths of the clamps 30a, 30b, 31a, and 31b are set to be equal to or slightly longer than the width of the workpiece W with respect to the width of the workpiece W, and the width of the workpiece W is set to be longer. In this case, for example, it is preferable to set the length about several to 20% longer.

[Tension application process in current heating process]
Referring to FIGS. 5E and 5F, the movable clamp member 31 is moved by the upper and lower tension cylinders 33a and 33b during energization heating as the energization time elapses, the energization current is accumulated, or the workpiece W is heated. The pair of upper and lower clamps 31 a and 31 b gradually move toward the longitudinal end of the workpiece W in synchronization with the expansion of the workpiece W that is thermally expanded while holding the other side of the workpiece W. Thereby, in particular, the tension acts on the workpiece W toward the front in the moving direction of the movable clamp member 31. Further, the clamp interval at the end of energization is expanded to “L +” with respect to the clamp interval “L” at the start of energization. That is, at the time of energization heating, the clamping interval is expanded by the extension of the workpiece W, that is, “L +” − “L”. Note that the distance between the clamp position by the upper and lower clamps 31a and 31b at the start of energization in FIG. 5D and the left end of the work W in the drawing is “D”, and the upper and lower clamps 31a and 31b at the end of energization in FIG. Assuming that the distance between the clamping position of the workpiece and the left end of the workpiece W in the drawing is “E”, “D” and “E” are the same length, or “E”, which is the distance after thermal expansion, is the distance before thermal expansion. It is slightly longer than “D”.

  As described above, according to the energization heating apparatus according to the embodiment of the present invention, during the energization heating, an appropriate tension is always applied at an appropriate clamp position to the workpiece W that expands as the temperature rises. Therefore, drooping of the center part of the workpiece W due to energization heating is prevented as much as possible.

  On the other hand, according to the energization heating apparatus according to the comparative example shown in FIG. 6, the two clamp positions are fixed, and the clamp interval between them is “L” and constant. That is, since the restraining positions at both ends in the longitudinal direction of the workpiece W are unchanged, it is not possible to continue applying an effective tension to the workpiece W that expands as the temperature rises during energization heating, and the central portion of the workpiece W hangs down. It will warp upward.

  The electric heating apparatus according to the present invention is suitably incorporated in a hot press molding apparatus, particularly a die quench apparatus. The electric heating device and the electric heating method according to the present invention are applied to heating of a metal plate material that is hot press formed, in particular, a plate material having a length, and specifically for vehicles that require mass productivity. The present invention is applied to heating before molding of parts, for example, various reinforcing materials for vehicle bodies, particularly heating before hot molding of door beams and bumper reinforcements.

1 is an external view of a hot press forming apparatus in which an electric heating apparatus according to an embodiment of the present invention is incorporated. (A)-(C) are three views for demonstrating the mechanical structure of the electric heating apparatus thru | or hot press molding apparatus shown in FIG. 1, (A) is a top view, (B) is a front view. FIG. 3C is a side view. FIG. 3 is an enlarged view of FIG. It is a block diagram for demonstrating the control structure of the electricity heating apparatus shown in FIG. (A)-(F) are process drawings explaining operation | movement of the electric heating apparatus shown in FIG.3 and FIG.4. It is process drawing for demonstrating the problem of the electric heating apparatus with a fixed clamp space | interval L which concerns on a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot press molding apparatus 2 Feeding mechanism 3 Current heating apparatus 4 Hot press mechanism 5 Transfer mechanism 6 Control mechanism 7 Conveyor 30 Fixed clamp member 30a, 30b Vertical clamp 31 Movable clamp member 31a, 31b Vertical clamp 32 Lifting cylinder ( Elevating direction drive mechanism)
33a, 33b Upper and lower tension cylinders (movable clamp member drive mechanism, clamp interval variable mechanism)
34, 34 Vertical motion guides (30, 31, 32, 33a, 33b, 34) Clamp mechanism 35 Support rod 36a Current sensor 36b Temperature sensor 36c Elevating position sensor 36d Movable clamp member position sensor 36e Control panel (control means) , Microcomputer)
37 Energizing mechanism 37a Energizing switch 38a, 38b Upper and lower frames 39a, 39b Upper and lower support columns (support members)
41 dies, cooling dies 51 a pair of parallel arms 52a to 52c cylinders (driving means)
53 Holder (clamp, holding means)
54 Support rod L, L + Clamping interval P Power supply P0 Input position P1 Energizing position P2 Processing position P3 Discharging position W Work D Distance between the movable clamp position at the start of energization and the left end of the work W in the figure E Moving clamp position at the end of energization And the left edge of the workpiece W in the figure

Claims (10)

An energizing heating device that energizes and heats a workpiece that is hot press-molded by a clamp mechanism and applies tension,
The clamping mechanism is
A fixed clamping member that clamps one side of the workpiece and can hold the one side of the workpiece and can be fixed in position or fixed along a predetermined direction;
A movable clamp member that clamps the other side of the workpiece and can hold the other side of the workpiece and move along a predetermined direction;
Have
During energization heating, the fixed clamp member holds one side of the workpiece in a fixed position, and the movable clamp member holds the other side of the workpiece along with the thermal deformation along the predetermined direction of the workpiece. A tension is applied to the workpiece by moving along
An electric heating device characterized by that. The clamping mechanism is
An elevating direction drive mechanism for driving the fixed clamp member and the movable clamp member to move up and down along the thickness direction of the work to clamp the work;
A movable clamp member driving mechanism for movably driving the movable clamp member along the predetermined direction;
The electric heating apparatus according to claim 1, wherein   3. The energization according to claim 1, wherein each of the fixed clamp member and the movable clamp member includes a pair of upper and lower clamps facing each other in the thickness direction of the workpiece and capable of sandwiching the workpiece. Heating device.   Of the pair of upper and lower clamps respectively provided in the fixed clamp member and the movable clamp member, the lower clamps spaced apart from each other along the predetermined direction are a pair of electrodes for energizing the workpiece. The energization heating apparatus according to claim 3. The portion of the upper clamp that holds the workpiece is a convex curved surface,
The portion of the lower clamp that holds the workpiece is planar.
The energization heating apparatus according to claim 3 or 4, characterized in that.   The electric heating apparatus according to any one of claims 1 to 5, further comprising a drooping prevention member that is disposed below the central portion of the workpiece during the electric heating and is capable of supporting the central portion.   The current heating apparatus according to claim 6, wherein the drooping prevention member is a plurality of pins erected along the vertical direction. An energizing heating device that energizes and heats a workpiece to be hot pressed by a clamp mechanism and applies tension,
The clamping mechanism is
First and second clamping members that clamp the workpiece at different clamping positions and apply tension to the workpiece;
A clamp direction drive mechanism for driving the first and second clamp members to clamp the workpiece;
A clamp interval variable mechanism that varies the clamp interval by the first and second clamp members according to thermal deformation of the workpiece during energization heating;
An energizing heating device characterized by comprising:   A hot press comprising: the energization heating device according to any one of claims 1 to 8; and a hot press mechanism that hot press-molds the workpiece heated by the energization heating device. Molding equipment. An energization heating method of energizing and heating while applying a tension by clamping a workpiece to be hot pressed,
A clamping step of applying tension while holding the workpiece by clamping one side and the other side of the workpiece;
An energization heating step of energizing and heating the clamped workpiece;
In the energization heating step, energization is performed by applying a tension to the work by clamping one side of the work at a fixed position and moving the position at which the other side of the work is clamped together with the work to be thermally deformed. Tension application process during heating,
An electric heating method characterized by comprising.

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