JP5277394B2 - Plate edge detection device using high frequency induction heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent falling-off of a heater from a plate end part. <P>SOLUTION: A plate end part detection device utilizing a high frequency induction heating device, is formed of: a magnetic field detection coil 16 arranged and installed coaxially with an induction heating coil on the upper side of the heater 5 of the high frequency induction heating device; and the end part detector 17 to send the plate end part detection signal 21 based on an output value of the magnetic field detection coil 16. When the heater 5 approaches the plate end part of a bending object steel plate 6, since an eddy current 19 induced in the vicinity of a surface of the bending object steel plate 6 by a magnetic field having alternating magnetic flux 8 generated by the induction heating coil of the heater 5 is deformed from a round shape, the magnetic field fluctuations occur to increase output value of the magnetic field detection coil 16. When the output value of the magnetic field detection coil 16 detected by the end part detector 17 exceeds threshold value, the end part detector 17 sends the plate end part detection signal 21, and movement of the heater 5 is stopped based on the plate end part detection signal 21. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  According to the present invention, the above-mentioned heater in the high-frequency induction heating apparatus configured to perform high-frequency induction heating of the scanning line portion of the steel plate while scanning a required position on the steel plate with a heater equipped with an induction heating coil is provided from the end of the steel plate. The present invention relates to a plate end detection device using a high frequency induction heating device for detecting the position of the plate end of the steel plate so as not to drop off.

  In general, a bending method by linear heating is often employed for bending a metal plate used for ships, bridges, and the like.

  This bending process by linear heating utilizes the property that if a metal plate is locally heated in a linear form with a required point heat source, it will be restrained by the surroundings and plastic deformation will be generated and deformed. This is a technique for bending a target metal plate into a target curved surface by arranging in the above.

  Conventionally, bending of a metal plate by linear heating is regarded as a skill that can be acquired after a long experience, and an expert determines the heating position, direction, heating conditions, etc. by intuition and skill. However, in recent years, as a method of performing linear heating mechanically, the finite element method (FEM) is applied to divide the metal plate surface to be bent into a number of regions, and for each of the divided regions, In order to obtain the target inherent strain required for bending into the target shape, and to give the in-plane shrinkage strain component and the bending strain component of the target inherent strain, for example, in the above-mentioned divided region on one side of the metal plate (steel to be bent), A curved scanning line (heating line) is crossed and the amount of heat input is changed mainly using the moving speed (scanning speed) of the heating source as a control parameter while moving the heating source along the scanning line. Then, each scanning line set on the metal plate is locally heated with a predetermined heat input amount, and each divided region is individually bent to a target shape, thereby bending the entire metal plate to a target curved surface. Be picked up To have.

  Further, it has been proposed to use a high-frequency induction heating coil as a point heat source for performing the above-described linear heating, and this type of high-frequency induction heating coil is used as a heating source to linearly heat a steel plate to be bent. As an apparatus for this purpose, the present applicant has proposed a high-frequency induction heating apparatus as schematically shown in FIG. 5 and FIG.

  That is, in the high frequency induction heating apparatus, as shown in FIGS. 5 and 6, a gantry (a gate-shaped frame) 1 including a beam 2 and a pedestal 3 supporting the beam 2 is arranged in a uniaxial direction in a horizontal plane. A heater elevator (arm) 4 capable of traveling in the direction of the arrow X and extending and contracting in the vertical direction (Z direction) can be traversed in the Y direction perpendicular to the X direction in a horizontal plane. Provide. Further, the central portion of the disk-shaped heater 5 is attached to the lower end of the heater elevator 4 so as to be able to swing (turn) in any direction via a universal joint (not shown), and the lower surface side of the heater 5 As an induction heating coil having an axial center in the vertical direction, for example, an induction heating coil (not shown) having a spiral shape (so-called pancake type) wound in the same plane is provided.

  According to the high frequency induction heating apparatus having the above configuration, the gantry 1 is controlled in the X direction by traveling in the X direction and the heater elevator 4 is moved in the Y direction, so that the lower end of the heater elevator 4 is controlled. The attached heater 5 is moved at a desired moving speed along a scanning line (not shown) set on the surface portion of the bending target steel plate 6. Further, at this time, by controlling the expansion / contraction operation in the vertical direction (Z direction) so that the reaction force received from the surface of the bending target steel plate 6 via the heater 5 is constant for the heater elevator 4. When the heater 5 is moved along the scanning line set on the surface portion of the steel plate 6 to be bent, the surface of the steel plate 6 to be bent is always continuously and complicatedly deformed by heating. Is moved up and down following the curved surface shape of the steel plate 6 and is slid while being in close contact with the surface of the steel plate 6 to be bent, and thereby the induction heating coil (not shown) provided on the lower surface side of the heater 5 is used. High-frequency induction heating of the bending target steel plate 6 can be performed with good heating efficiency (see, for example, Patent Document 1).

  FIG. 7 shows an outline of a control system of the high-frequency induction heating device having the above-described configuration. For example, a traveling drive device 8 for causing the gantry 1 to travel in the X direction shown in FIGS. The operation (movement or stop) of the heater drive device 7 including the traverse drive device 9 for causing the heater elevator 4 shown in FIG. 5 and FIG. 6 to traverse in the Y direction, and the heater 5 The system management terminal 10 for creating and managing the NC program 11 for determining the operation (heating on or off), respectively, and the X of the heater 5 by the driving device 7 according to the NC program 11 received from the system management terminal 10 A configuration including an NC controller (control panel) 12 for giving an operation control command 13 in the -Y direction and for giving an operation control command 14 for turning on or off heating to the heater 5; And Aru. As a result, the NC controller 12 that has received the NC program 11 from the system management terminal 10 gives the operation control commands 13 and 14 to the driving device 7 and the heater 5, respectively. The linear heating work is performed while appropriately controlling the movement and stop at the required moving speed along the scanning line set in (refer to FIG. 5 and FIG. 6) and the heating on and off. When the predetermined work is completed, an operation completion signal 15 is transmitted from the NC controller 12 to the system management terminal 10.

  By the way, when performing the bending process by the linear heating of the steel plate 6 to be bent by the high frequency induction heating apparatus shown in FIGS. 5 and 6, each of the scanning lines on the steel plate 6 to be bent is sequentially heated so as to be bent. Since the steel plate 6 is always continuously and complicatedly deformed, the absolute position of each scanning line set on the deformed bending target steel plate 6 is the scanning line set on the initial shape bending target steel plate 6. It will be displaced from the absolute position. Therefore, when creating the NC program 11 related to the movement of the heater 5 in the XY direction at the system management terminal 10, each scanning line set on the bending target steel plate 6 is usually set. When the heating is sequentially performed in a predetermined order, the change in the position of the scanning line due to the bending deformation continuously generated in the bending target steel plate 6 is calculated in advance, and is made to correspond to the calculated position of the scanning line after the displacement. An NC program is prepared so that the heater can be arranged.

Japanese Patent No. 2666685

  However, as described above, in the system management terminal 10 of the high-frequency induction heating apparatus, after considering the displacement of the scanning line accompanying the deformation occurring in the bending target steel plate 6, the heater 5 is made to correspond to the displaced scanning line. Since the NC program 11 is created so that it can move, the movement range in the XY direction of the heater 5 is usually the planar shape of the bending target steel plate 6 on which scanning lines are set. Although it should fall within the range, during the process of bending the steel plate 6 to be bent, due to factors such as excessive shrinkage or excessive bending of the steel plate 6 to be bent due to heating and cooling, If the plate end position of the bending target steel plate 6 deviates from the plate end position assumed when the NC program 11 is created by the system management terminal 10, the NC program created by the system management terminal 10 1, when the NC controller 12 gives an operation control command to the drive device 7 to cause the heater 5 to move in the X-Y direction, the heater 5 exceeds the end of the bending target steel plate 6. The actual situation is that there is a risk that it will move and fall outside the bending target steel plate 6.

  If the heater 5 falls off from the end of the steel plate 6 to be bent as described above, there is a concern that the heater 5 may be damaged or that the end of the steel plate 6 to be bent may be melted by heating. Therefore, during the operation of the high frequency induction heating apparatus, monitoring by an operator is required. If the heater 5 is likely to exceed the end of the steel plate 6 to be bent, the operator immediately The operation of the high frequency induction heating device was stopped. Therefore, at present, it is possible to perform the processing in the unsupervised leaving operation, for example, the target curved surface is a saddle shape or the like, and a desired target curved surface is obtained even if heating near the plate end of the steel plate 6 to be bent is omitted. Therefore, it is limited to the shape of the pile that can be obtained, and as a result, it is one of the factors that hinder the separation of bending of steel sheets by linear heating using a high-frequency induction heating device. It is.

  Therefore, the present invention provides a high-frequency induction heating apparatus in which a heater provided with a high-frequency induction heating coil is moved along the surface of the steel sheet and the required portion of the steel sheet is heated. A plate by a high-frequency induction heating device that can automatically detect the approach when approaching the plate end of the steel plate and prevent the heater from falling off the steel plate end. An end detection device is to be provided.

In order to solve the above problems, the present invention, corresponding to claim 1, performs high-frequency induction heating of a steel plate by the heater while moving the heater provided with the induction heating coil along the surface of the steel plate. In the high-frequency induction heating apparatus, the heater is provided with a magnetic sensor for detecting a magnetic field having an alternating magnetic flux generated by the induction heating coil, and the output of the magnetic sensor is generated by the induction heating coil. It is set as the structure provided with the edge part detector which detects the board edge part of the said steel plate based on changing depending on the fluctuation | variation of the magnetic field provided with the alternating magnetic flux to make.

  In the above configuration, when the shape of the eddy current induced near the surface of the steel sheet by the magnetic field generated by the induction heating coil of the heater is deformed due to the restriction by the edge of the steel sheet By detecting the fluctuation generated in the magnetic field based on the change in the output of the magnetic sensor, it is configured to have a function of detecting the end portion of the steel plate.

  Further, in each of the above configurations, the magnetic sensor is configured as a magnetic field detection coil having an axis perpendicular to the arrangement surface of the induction heating coil of the heater.

  In each of the above-described configurations, a magnetic field detection coil is provided on the upper side of the heater so as to be disposed concentrically with the heater.

Similarly, in each structure described above, the upper outer peripheral portion of the heater, the structure was provided a plurality of magnetic field detecting coils in the circumferential direction.

According to the plate edge detection device using the high frequency induction heating device of the present invention, the following excellent effects are exhibited.
(1) The induction heating coil in the high-frequency induction heating apparatus configured to perform high-frequency induction heating of the steel plate by the heater while moving the heater provided with the induction heating coil along the surface of the steel plate. A magnetic sensor for detecting a magnetic field having an alternating magnetic flux generated by the magnetic field sensor, and further, the output of the magnetic sensor changes depending on the fluctuation of the magnetic field having the alternating magnetic flux generated by the induction heating coil. A configuration comprising an end detector for detecting the end of the steel plate based on the above, more specifically, the end detector is guided near the surface of the steel plate by a magnetic field generated by an induction heating coil of the heater. Detection of the edge of the steel sheet by detecting the variation in the magnetic field based on the change in the output of the magnetic sensor when the shape of the eddy current to be deformed is limited by the edge of the steel sheet. Since it is configured to have a function to perform, the eddy current induced near the surface of the steel sheet by the magnetic field generated by the induction heating coil of the heater of the high frequency induction heating device is from a concentric circle with the induction heating coil, The magnetic field fluctuation caused by deformation due to the restriction by the plate edge of the steel plate can be captured by a magnetic sensor, and therefore the high frequency induction is performed by an end detector based on the output of the magnetic sensor. It can be detected that the heater of the heating device is approaching the plate end of the steel plate. Therefore, by stopping the movement of the heater in the high frequency induction heating device when the approach of the heater to the plate end of the steel plate is detected as described above, the steel plate of the heater is stopped. Since it becomes possible to prevent the falling off from the end portion, it becomes possible to prevent the damage accompanying the dropping off of the heater and the melting out of the end portion of the steel plate, and the high frequency induction heating device It is possible to reduce the hand.
(2) Since the magnetic sensor detects the fluctuation of the magnetic field formed by flowing a high-frequency current through the induction heating coil, which is the principle of high-frequency induction heating, it does not require a complicated apparatus configuration. With a simple configuration, it is possible to realize an apparatus that easily and reliably detects the approach of the heater to the plate end of the steel plate.
(3) By configuring the magnetic sensor as a magnetic field detection coil having an axis perpendicular to the placement surface of the induction heating coil of the heater, the magnetic flux alternating with the magnetic field formed by the induction heating coil of the heater is traversed. Since the magnetic field detection coil can be arranged as described above, the magnetic field fluctuation can be efficiently detected by the magnetic field detection coil.
(4) By adopting a configuration in which a magnetic field detection coil is provided concentrically with the heater on the upper side of the heater, the heater approaches the plate edge of the steel plate from any place in the circumferential direction. However, since the fluctuation of the magnetic field formed by the induction heating coil of the heater that occurs at that time can be detected by one magnetic field detection coil, the configuration can be made advantageous for a simple device configuration. .
(5) By adopting a configuration in which a plurality of magnetic field detection coils are provided in the circumferential direction on the upper side of the outer peripheral portion of the heater, the approach to the plate end of the steel plate of the heater is changed in the circumferential direction of the heater. Therefore, it is possible to detect with high accuracy that the heater has approached the end of the steel plate. In addition, since it becomes possible to detect from which direction the heater approaches the plate end of the steel plate, the heater approaches the plate end of which portion of the steel plate. It can also be detected.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIGS. 1A, 1B, and 3 show an embodiment of a plate edge detection device using a high-frequency induction heating device according to the present invention, which is as follows.

  That is, the plate edge part detection device using the high frequency induction heating device of the present invention is not shown in the high frequency induction heating device having the same configuration as shown in FIGS. 5 and 6 as shown in FIGS. In the heater 5 equipped with the induction heating coil, a magnetic field detection coil 16 as a magnetic sensor is provided, and an end detector 17 is connected to the magnetic field detection coil 16. Based on the fluctuation of the output value 20 of the magnetic field detection coil 16 accompanying the change of the magnetic field generated when the heater 5 approaches the plate end of the bending target steel plate 6, the determination of the plate end of the bending target steel plate 6; It is set as the structure which performs a detection.

  More specifically, the magnetic field detection coil 16 is formed as a single coil on the upper side of the heater 5, and the axis of the magnetic field detection coil 16 in a direction perpendicular to an arrangement surface of an induction heating coil (not shown) of the heater 5. It arrange | positions so that it may become concentric with the induction heating coil (not shown) of the pancake type | mold which is equipped with this heater 5 so that it may become the attitude | position which a heart direction corresponds.

  Here, the principle of the high frequency induction heating apparatus will be described. When a high frequency current is passed through a pancake type induction heating coil (not shown) provided in the heater 5 in the high frequency induction heating apparatus, As shown in FIG. 1 (a), a strong magnetic field having an alternating magnetic flux 18 passing through the induction heating coil (not shown) in the axial direction is formed, and the alternating magnetic flux 18 is formed on the lower side of the heater 5. By penetrating the bending target steel plate 6 disposed in the vicinity, a high-density eddy current 19 is induced near the surface of the bending target steel plate 6, and Joule heat associated with electric resistance when the eddy current 19 flows. Thus, the bending target steel plate 6 is heated by self-heating.

  Therefore, since the magnetic field detection coil 16 attached to the upper side of the heater 5 is disposed so as to cross a strong magnetic field having the alternating magnetic flux 18, the output value 20 of the magnetic field detection coil 16 is the alternating value. It depends on the fluctuation of the magnetic field having the magnetic flux 18.

  By the way, as shown to FIG. 1 (a), when the heater 5 of the said high frequency induction heating apparatus is arrange | positioned on the upper side of the part which has left | separated from the board edge part of the bending target steel plate 6, the said heater 5 The eddy current 19 induced near the surface of the bending target steel plate 6 by the magnetic field generated by the induction heating coil (not shown) of the heater 5 flows concentrically with the induction heating coil (not shown) of the heater 5.

  As described above, the heater 5 is sufficiently separated from the end of the steel plate 6 to be bent, and an eddy current 19 induced near the surface of the steel plate 6 to be bent is connected to an induction heating coil (not shown) of the heater 5. If the heater 5 is in a concentric flow state, even if the heater 5 moves on the bending target steel plate 6, the magnetic field having the alternating magnetic flux 18 formed by the heater is hardly disturbed. The output value 20 of the magnetic field detection coil 16 provided on the vessel 5 hardly fluctuates as shown by a region A in FIG.

  On the other hand, when the heater 5 is disposed on the upper side of the vicinity of the plate end of the bending target steel plate 6, the vicinity of the surface of the bending target steel plate 6 is generated by a magnetic field generated by an induction heating coil (not shown) of the heater 5. As shown in FIG. 1 (b), the eddy current 19 induced by the current flows concentrically with an induction heating coil (not shown) of the heater 5 by being limited by the end of the steel plate 6 to be bent. The shape of the eddy current 19 becomes more deformed as the heater 5 approaches the end of the steel plate 6 to be bent.

  When the eddy current 19 is disturbed as described above, the magnetic field having the alternating magnetic flux 18 is also disturbed. Therefore, as the magnetic field is disturbed, the magnetic field having the alternating magnetic flux 18 is arranged in the magnetic field. The output value 20 of the magnetic field detection coil 16 also fluctuates, and the output value of the magnetic field detection coil 16 increases as the heater 5 approaches the end of the steel plate 6 to be bent, as indicated by region B in FIG. The amount of variation of 20 increases.

  In view of the above points, in the present invention, the end detector 17 has a function of constantly monitoring the output value 20 of the magnetic field detection coil 16, and the heater 5 is attached to the end of the steel plate 6 to be bent. When approaching, the output value 20 of the magnetic field detection coil 16 immediately before the center of the heater 5 reaches the end of the steel plate 6 to be bent is set as a threshold value as indicated by a line C in FIG. When the output value 20 of the magnetic field detection coil 16 exceeds the threshold value, it is determined that the heater 5 is approaching the plate end of the bending target steel plate 6, and the plate end detection signal 21 is detected. Has a function of transmitting (outputting).

  FIG. 3 shows a case where the plate end detection device by the high frequency induction heating device of the present invention comprising the magnetic field detection coil 16 and the end detector 17 is incorporated in the control system of the same high frequency induction heating device as shown in FIG. For example, in the same configuration as shown in FIG. 7, the plate end detection signal 21 transmitted from the end detector 17 can be received by the NC controller 12. And when the NC controller 12 receives the plate edge detection signal 21 transmitted from the edge detector 17, the sub-program for the edge detection operation is interrupted and executed instead of the normal NC program 11, thereby heating. The operation control command 13 for stopping the operation is immediately issued to the drive device 7 of the heater 5 and the operation control command 14 for turning off the heating is immediately issued to the heater 5. Further, when a plate edge detection signal 21 from the edge detector 17 is input to the NC controller 12, the board edge such as the date and time when the plate edge is detected and the operation contents are sent to the system management terminal 10. The function of transmitting the part detection information 22 is provided.

  In addition, the code | symbol 4 in FIG. 1 (I) (B) shows a heater elevator. In addition, in FIG. 3, the same components as those shown in FIG.

  According to the plate edge detection device using the high-frequency induction heating device of the present invention having the above-described configuration, the heater 5 of the high-frequency induction heating device is scanned along a scanning line (not shown) set on the steel plate 6 to be bent. When the heating target 5 approaches the plate end of the bending target steel plate 6 while the heating of the bending target steel plate 6 is being performed, the center of the heater 5 becomes the plate end of the bending target steel plate 6. The plate edge detection signal 21 is transmitted from the edge detector 17 immediately before reaching.

  Therefore, as shown in FIG. 3, when the plate end detection signal 21 is transmitted from the end detector 17, the operation to the drive device 7 is stopped by the NC controller 12 in the control system of the high frequency induction heating device. When the operation control command 13 to be performed and the operation control command 14 to turn off the heating to the heater 5 are transmitted, even if the heater 5 approaches the plate end of the steel plate 6 to be bent, the heater Since the operation of the heater 5 is automatically stopped and the heating by the heater 5 is automatically turned off immediately before the center of the plate 5 crosses the end of the steel plate 6 to be bent, the heater It is possible to prevent the possibility that 5 is dropped from the end portion of the steel plate 6 to be bent and is damaged, or that the end portion of the steel plate 6 to be bent is melted by heating. Therefore, the high frequency induction heating apparatus can be separated from the hand.

  Furthermore, the plate edge part detection device by the high frequency induction heating device of the present invention has a magnetic field detection coil 16 provided in the heater 5 of the high frequency induction heating device, and an output value 20 of the magnetic field detection coil 16 exceeds a predetermined threshold value. And the edge detector 17 that transmits the plate edge detection signal 21, and the number of turns of the magnetic field detection coil 16 may be one, and further, the magnetic field detection coil 16 detects the number of turns. Since the fluctuation of the magnetic field having an alternating magnetic flux formed by flowing a high-frequency current through the induction heating coil, which is the principle of high-frequency induction heating, the heater 5 can easily approach the plate end of the steel plate 6 to be bent and A device that detects reliably can be realized with a very simple configuration.

  Next, FIG. 4 shows an application example of the embodiment shown in FIGS. 1 (a) and (b) and FIG. 3 as another embodiment of the present invention. FIGS. In the configuration similar to that shown in FIG. 1, one magnetic field detection coil 16 arranged concentrically with a pancake-type induction heating coil (not shown) of the heater 5 is provided above the heater 5 of the high-frequency induction heating device. Instead, a plurality of magnetic field detection coils 16a are provided above the outer peripheral portion of the heater 5 at a required interval in the circumferential direction.

  Specifically, for example, on the upper side of the four positions at intervals of 90 degrees in the circumferential direction, which are arranged so as to substantially face the four plate end portions of the steel plate 6 to be bent at the outer peripheral portion of the heater 5, FIG. A) A magnetic field detection coil 16a smaller than the magnetic field detection coil 16 shown in (b), and a pancake type induction heating coil (not shown) in which the axial direction of each magnetic field detection coil 16a is provided in the heater 5 It arrange | positions so that it may become parallel to an axial center direction, and it is set as the structure attached to the said heater 5. FIG. As a result, magnetic field fluctuations due to the alternating magnetic flux passing through the respective locations are detected at four locations in the circumferential direction, which are arranged so as to substantially face the four end portions of the bending target steel plate 6 at the outer peripheral portion of the heater 5. You can do that.

  Each of the magnetic field detection coils 16a may be a single coil as in the case of the magnetic field detection coil 16 shown in FIGS.

  Although not shown, each of the magnetic field detection coils 16a is connected to an end detector similar to the end detector 17 shown in FIGS. 1A and 1B, and the end detector. 2, the output value of each magnetic field detection coil 16a is individually monitored, and the output value of any one of the magnetic field detection coils 16a is a predetermined value. When the threshold value is exceeded, a plate end detection signal 21 is transmitted from the end detector to the NC controller 12 in the same manner as shown in FIG.

  Also according to the present embodiment, the same effects as those of the embodiment shown in FIGS. Furthermore, each magnetic field detection coil 16a provided on the outer periphery of the heater 5 of the high-frequency induction heating device can detect a magnetic field variation due to an alternating magnetic flux passing through the installation location of each magnetic field detection coil 16a. When the heater 5 of the high-frequency induction heating apparatus approaches the end of the steel plate 6 to be bent, of the four circumferential locations where the magnetic field detection coils 16a are installed on the outer periphery of the heater 5. When any one point reaches the plate end of the steel plate 6 to be bent, the output value of the magnetic field detection coil 16a installed at that point is higher than the output value of each magnetic field detection coil 16a at the other point. Therefore, it becomes possible to detect with high accuracy that the heater 5 has approached the plate end of the steel plate 6 to be bent. Moreover, since it becomes possible to detect from which direction the heater 5 is approaching the plate end of the steel plate 6 to be bent, for example, the heater 5 is 4 of the steel plate 6 to be bent. It is possible to efficiently detect which one of the plate ends is approaching.

  In addition, this invention is not limited only to said each embodiment, The winding number of the magnetic field detection coils 16 and 16a is good also as two or more turns.

  From the viewpoint of efficiently detecting the four plate end portions of the bending target steel plate 6, the magnetic field detection coil 16a provided on the upper side of the outer peripheral portion of the heater 5 in the embodiment of FIG. However, the number of magnetic field detection coils 16a installed in the circumferential direction may be appropriately increased or decreased depending on the size of the heater 5 and the like. .

  As control of the control system of the high frequency induction heating device based on the plate end detection signal 21 transmitted from the end detector 17, the plate end detection signal 21 transmitted from the end detector 17 is sent to the NC controller 12. The NC controller 12 has received and indicated that the operation of the drive device of the heater 5 is stopped and the heating by the heater 5 is turned off. At least the heater 5 is a steel plate 6 to be bent. If the movement in a direction closer to the plate end of the steel plate is stopped to prevent the heater 5 from falling off the plate end of the steel plate 6 to be bent, for example, Based on the plate edge detection signal 21 transmitted from the edge detector 17, the NC controller 12 generates an alarm to notify the operator when stopping the movement of the heater 5, The heater 5 is moved to the next scanning line set on the target steel plate 6 and heating by the heater 5 at a location along the next scanning line is started, etc. other than those shown in the embodiment of FIG. You may make it perform the process of.

  The magnetic field detection coils 16 and 16a are exemplified as the magnetic sensor provided in the heater 5. However, if the change of the magnetic field having the alternating magnetic flux 18 generated by the induction heating coil of the heater 5 can be detected, the magnetic field detection is performed. Any type of magnetic sensor other than the coils 16 and 16a may be used.

  The plate edge detection device by the high frequency induction heating device of the present invention is a high frequency induction heating device of a type in which the heater 5 having an induction heating coil is moved along the surface of a steel plate (metal plate). If it exists, you may apply to any high frequency induction heating apparatuses other than the high frequency induction heating apparatus which performs linear heating.

  In each of the above embodiments, assuming that the induction heating coil (not shown) of the heater 5 of the high frequency induction heating apparatus is a pancake type induction heating coil, the heater 5 is separated from the plate end of the steel plate 6 to be bent. In the case where the heater 5 is arranged above, a magnetic field generated by an induction heating coil (not shown) of the heater 5 induces an eddy current 19 concentric with the heater 5 near the surface of the steel plate 6 to be bent. Although shown as a thing, if the heater 5 is moved along the surface of a steel plate (metal plate) so that the steel plate can be heated, the induction heating coil provided in the heater 5 is provided. The shape of is an induction heating coil having an arbitrary shape other than the pancake mold, and when the heater 5 is disposed on the upper side of the portion separated from the plate end of the steel plate, the steel plate has an arbitrary shape other than a circle. Shape eddy current It may be each other so as to guide. In this case, the magnetic field detection coils 16 and 16a have an eddy current shape other than a circular shape induced in the steel plate by the induction heating coil of the heater 5, but the heater 5 is separated from the plate end of the steel plate. The output value 20 fluctuates due to the disturbance of the magnetic field caused by deformation due to the restriction of the plate end portion as it approaches the plate end portion of the steel plate from the state where it is disposed on the upper side of the plate. As long as it is provided.

  Of course, various modifications can be made without departing from the scope of the present invention.

1 shows an embodiment of a plate edge detection device using a high frequency induction heating device according to the present invention, wherein (a) is when the heater of the high frequency induction heating device is located away from the plate edge of the steel plate to be bent. (B) is a schematic diagram showing the state when the heater is in a position close to the end of the steel plate to be bent. It is a figure which shows the judgment criteria of the detection of the board edge part based on the output value of a magnetic field detection coil in the edge part detector of the apparatus of FIG. It is a schematic diagram which shows an example in the case of incorporating the apparatus of FIG. 1 in the control system of a high frequency induction heating apparatus. It is a schematic perspective view which shows the magnetic field detection coil part of other form of implementation of this invention. It is a front view which shows the outline of an example of the high frequency induction heating apparatus for performing the linear heating which the present applicant has proposed previously. FIG. 6 is a schematic cut side view of the apparatus of FIG. 5. It is a figure which shows an example of the control system of the apparatus of FIG.

Explanation of symbols

5 Heater 6 Bending steel plate (steel plate)
16, 16a Magnetic field detection coil (magnetic sensor)
17 End detector 18 Alternating magnetic flux 19 Eddy current 20 Output value (output)

Claims (5)

A high-frequency induction heating apparatus configured to perform high-frequency induction heating of a steel plate by the heater while moving the heater provided with the induction heating coil along the surface of the steel plate is generated by the induction heating coil. A magnetic sensor for detecting a magnetic field having an alternating magnetic flux is provided, and further, the steel plate is based on the fact that the output of the magnetic sensor changes depending on the variation of the magnetic field with the alternating magnetic flux generated by the induction heating coil. A plate end detection device using a high frequency induction heating device, comprising: an end detector for detecting the end of the plate.   When the shape of the eddy current induced near the surface of the steel sheet by the magnetic field generated by the induction heating coil of the heater is deformed due to the restriction by the plate edge of the steel sheet, the end detector is deformed. The high frequency induction heating according to claim 1, wherein the plate edge portion of the steel sheet is detected by detecting fluctuations in the magnetic field caused by deformation of the magnetic sensor based on changes in the output of the magnetic sensor. A plate edge detecting device.   3. A plate end detection device using a high frequency induction heating device according to claim 1, wherein the magnetic sensor is a magnetic field detection coil having an axis center perpendicular to the arrangement surface of the induction heating coil of the heater.   4. A plate end detection apparatus using a high frequency induction heating apparatus according to claim 3, wherein a magnetic field detection coil is disposed on the upper side of the heater so as to be concentric with the heater. On the upper side of the outer peripheral portion of the heater, the circumferential direction to the plate edge detection device by high frequency induction heating device according to claim 3, wherein was set to provide a plurality of magnetic field detecting coil.

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