JP2010055814A - Induction heating furnace and heating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem in a heating method of carrying induction heating by changing magnetic resistance by the rotation of a magnetic member that cogging torque generated by a change of the magnetic resistance gives mechanical vibration which may cause damage to a device carrying out induction heating. <P>SOLUTION: In the induction heating furnace 100, the total strength of magnetic flux generated in an area of a space 20 does not change with time. However, out of a main surface of a heated object 16, magnetic flux reaching a local area changes with time. Thus, as mechanical vibration against a device as the whole of the induction heating furnace 100 is restrained, the heated object 16 is heated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an induction heating furnace and a heating method, and more particularly to an induction heating furnace that suppresses vibrations that occur during heating and a heating method using the induction heating furnace. .

  When a metal material is heated in hot forging or the like, the metal material may be directly heated using, for example, a burner or a heater. However, in recent years, the following method may be used in place of the above-described method of directly heating a metal material using a burner or a heater. Metal material that is an object to be heated (for example, a metal rod inserted into the inside of the coil) in the region through which the magnetic flux generated in the coil connected to the alternating current passes, that is, the inside of the coil or the longitudinal extension region of the coil An alternating current is passed through the coil in a state where is placed in a non-contact manner. If it does in this way, the eddy current by an electromagnetic induction effect will generate | occur | produce in the area | region near the surface of a metal material by the alternating current which flows into a coil. Therefore, as a result of the eddy current generating heat in the region near the surface of the metal material, the metal material can be heated.

In addition to the method for generating an eddy current due to the electromagnetic induction effect by passing an alternating current through the coil as described above, it is disclosed in, for example, Japanese Patent Laid-Open No. 60-10581 (hereinafter referred to as “Patent Document 1”). There is also a method of generating an eddy current due to the electromagnetic induction effect by using the following method. That is, a DC power source is supplied to the coil, and a magnetic member disposed in a region around the coil is rotated so that the magnetic resistance of the entire magnetic circuit including the coil is changed temporally. This is a method of generating heat by generating an eddy current in a metal material to be heated, which is disposed on the extended region.
JP-A-60-10581

  However, in the method disclosed in the seventh specific example of Patent Document 1, the magnetic resistance of the entire magnetic circuit is changed by rotating a rotor such as a magnetic member in a non-excited state. For this reason, a cogging torque that is a magnetic attraction force is generated in the magnetic circuit, and a change in the magnetic resistance may cause a mechanical vibration to the entire magnetic circuit device as a resistance force. In addition, when the object to be heated is made of a magnetic material, an attractive force works when the magnetic field in the area around the object to be heated changes. This is similar to the above-described cogging torque, and the magnetic circuit device. Mechanical vibration may be given to the whole. These mechanical vibrations may cause damage to the magnetic circuit device.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an induction heating furnace that suppresses vibrations that occur when heating is performed, and a heating method using the induction heating furnace. .

  An induction heating furnace according to one aspect of the present invention includes a fixed body connected to a DC power source, and a rotation that includes a magnetic material in a part on a main surface that is disposed in a space that forms a region where the fixed body is divided. A body and a rotation drive source for rotating the rotating body. Then, when the rotating body rotates, the magnetic flux density is locally changed in time within a space area that forms an area where the fixed body is divided. However, this is an induction heating furnace in which the magnetic flux does not change with time in the entire region of the space. The main surface refers to the main surface having the largest area among the surfaces.

  In the induction heating furnace according to one aspect of the present invention, more specifically, the entire rotating body is accommodated in a space area. By configuring as described above, if the rotating body rotates, for example, in a certain local region on the main surface of the object to be heated arranged in the region of the space forming the region where the stationary member is divided, The phase of the rotating body facing the region corresponds to a region including the magnetic material or a region not including the magnetic material, or changes with time by the rotation of the rotating body. For this reason, the magnetic flux which reaches | attains a certain area | region on the main surface of the to-be-heated object mentioned above changes according to the phase of the rotary body which the local area | region opposes. Specifically, when the phase of the rotating body facing a certain area on the main surface of the object to be heated changes due to rotation from the area containing the magnetic material to the area not containing, or the area not containing the magnetic substance The magnetic flux reaching a certain region on the main surface of the object to be heated changes when the region changes from to the region including it.

  As described above, an eddy current due to the electromagnetic induction effect is generated in the region where the reaching magnetic flux is changed. Therefore, an eddy current is generated in a certain region on the main surface of the object to be heated, and the region near the surface generates heat. As a result, the metal material can be heated.

  However, the magnetic flux that passes through the magnetic material included in a part of the rotating body always exists in a space region that forms a region where the fixed body is divided. Further, since the power source connected by winding a coil, for example, around the fixed body is a DC power source, the direction and strength of the magnetic flux generated inside the fixed body do not change with time. Therefore, even if the rotating body rotates, the magnetic flux does not change with time in the entire area of the space. That is, since the cogging torque due to the attractive force accompanying the temporal change of the magnetic field is not generated in the stationary body, mechanical vibrations for the entire apparatus of the induction heating furnace can be suppressed. As a result, damage to the induction heating furnace device can be suppressed. As described above, if the induction heating furnace according to one aspect of the present invention is used, an object to be heated can be heated while suppressing vibration.

  An induction heating furnace according to another aspect of the present invention is a rotating body including a magnetic material in a part on a main surface, disposed in a space that forms a fixed body connected to a DC power source and a region where the fixed body is divided. A body and a rotation drive source for rotating the rotating body. Then, when the rotating body rotates, the magnetic flux density is locally changed in time within a space area that forms an area where the fixed body is divided. And it is an induction heating furnace whose time change rate of the magnetic flux in the whole area | region of the said space is less than +/- 50%.

  In the induction heating furnace according to another aspect of the present invention, more specifically, for example, only a partial area of the rotating body is accommodated in a space area that forms an area where the stationary body is divided, and the rotating body is rotated. Some areas of the body may protrude beyond the space area. Even in the configuration as described above, when the rotating body rotates, the magnetic flux passing through the magnetic material included in a part of the rotating body in the area of the space forming the area where the stationary body is divided is temporally Preferably it does not change. However, for example, when a part of the rotating body is in a state of protruding outside the space area, the magnetic flux in the entire space area is always constant regardless of the rotation of the rotating body. May not be possible. Even in this case, as described above, if the time change rate of the magnetic flux in the entire area of the space is suppressed to within ± 50%, the mechanical force generated in the apparatus due to the cogging torque due to the attractive force generated by the change in the magnetic flux. Vibration can be suppressed within an allowable range. As described above, when the induction heating furnace according to another aspect of the present invention is used, an object to be heated can be heated while suppressing mechanical vibration generated in the induction heating furnace within an allowable range.

  In the induction heating furnace in one aspect of the present invention described above and the induction heating furnace in another aspect of the present invention, the main surface of the fixed body is formed by forming a space that forms a region where the fixed body is divided. For example, a C shape is formed. The area | region where the fixed body was divided | segmented is corresponded to the area | region where the curve was divided | segmented on the right side of C character.

  In the induction heating furnace according to one aspect of the present invention and the induction heating furnace according to another aspect of the present invention, the above-described fixed body is preferably formed by laminating silicon steel plates in a plurality of layers. In the step of forming the fixed body, for example, when forging is performed, in order to suppress the heat generation of the precursor of the fixed body itself, it is formed by laminating silicon steel sheets in a plurality of layers, For example, it is preferable to form a fixed body using a powder sintered iron core such as ferrite.

  In the induction heating furnace in one aspect of the present invention described above and the induction heating furnace in another aspect of the present invention, for example, a coil connected to a DC power source in a partial region of a fixed body that forms a C-shape, for example. It is preferable to connect the DC power source and the fixed body by winding the wire.

  In this way, the fixed body and the DC power source are connected via the coil. Then, since a direct current flows through the coil, the magnetic flux inside the fixed body does not change with time. As described above, the magnetic flux does not change (or very small) even when the rotating body rotates in the entire region where the fixed body is divided. For this reason, in the induction heating furnace according to the present invention, no cogging torque is generated due to the attractive force that accompanies the temporal change of the magnetic field, so that mechanical vibrations for the entire apparatus of the induction heating furnace can be suppressed. As a result, damage to the induction heating furnace device can be suppressed. As described above, it is preferable to connect the DC power supply and the fixed body by winding a coil connected to the DC power supply in a part of the fixed body.

  In the induction heating furnace according to one aspect of the present invention described above and the induction heating furnace according to another aspect of the present invention, it is more preferable to use a superconducting coil as a coil connected to the DC power source described above.

  When direct current is passed through the superconducting coil, almost no electrical resistance is generated inside the coil. For this reason, almost no heat is generated in the superconducting coil. Alternatively, the amount of heat generated in the superconducting coil can be minimized. Therefore, of the energy input to the induction heating furnace to heat the object to be heated, the rate of loss due to heat generated by the superconducting coil is extremely small. As described above, by using a superconducting coil as a coil connected to the DC power source, the energy to be input to the induction heating furnace to heat the object to be heated is used to drive the rotary drive source that rotates the rotating body with high efficiency. It can be used as energy. Further, since the energy loss due to heat generation can be reduced, the loss of direct current flowing through the superconducting coil is also reduced. As a result, the magnetic flux generated by the current flowing in the superconducting coil can be supplied with high efficiency into the space region that forms the region where the stationary body is divided, and the running cost of the entire induction heating furnace can be reduced.

  As described above, the coil is used to form a magnetic flux inside the fixed body by a current supplied from a DC power source. However, when the position of the coil is wound around an area of the fixed body that is close to the space, the magnetic flux generated inside the fixed body when a direct current is passed through the coil is efficiently generated in the area of the space. Can be supplied. As a result, the object to be heated can be efficiently heated.

  Therefore, it is more preferable that the coil described above is arranged by being wound in a region within 300 mm from at least one of a pair of surfaces facing a space forming a region where the fixed body is divided. . Specifically, an area within 300 mm from any one of the surfaces facing the space, that is, an area within 300 mm from one end of the C-shape forming the main surface, for example, when the fixed body has a C-shape. Only the coil may be wound. Or it is more preferable to arrange | position by winding a pair of coils in the area | region within 300 mm from each of a pair of surface facing the said space.

  In this way, if two coils are arranged in an area within 300 mm from both ends of the C shape so that the space is sandwiched, the magnetic flux that can be supplied in the area of the space is doubled. become. Therefore, the object to be heated can be heated more efficiently.

  The induction heating furnace in the present invention described so far uses a coil for supplying a direct current in order to supply a magnetic flux to a space forming a region where the stationary body is divided. However, for example, a permanent magnet made of a bulk superconductor having a C shape or a U shape may be used as a fixed body constituting the induction heating furnace without using a coil. In this way, even without using a DC power supply, a magnetic flux having a constant direction and strength is always present in the region of the space forming the divided region of the permanent magnet by the action of the permanent magnet. Therefore, even when a rotating body including a magnetic material at least partially on the main surface, which is disposed in the space area, rotates, the magnetic flux does not change with time in the entire space area. Further, for example, by forming the permanent magnet from a bulk superconductor, it is possible to minimize the amount of heat generated in the fixed body. As described above, even when a permanent magnet made of a bulk superconductor is used as means for supplying magnetic flux to the space, the same effect as that obtained when a coil is used is produced.

  Further, when a permanent magnet is used as the fixed body, a high-density magnetic flux is supplied from both ends of the divided region of the permanent magnet. For this reason, the magnetic flux in the area of the space that forms the divided area of the permanent magnet, for example, in the case of using the above-described coil, each of the pair of surfaces facing the space that forms the area where the fixed body is divided is used. This corresponds to a case where a coil is wound around a nearby region. Therefore, when a permanent magnet is used as the fixed body, the magnetic flux supplied to the space region by the permanent magnet is increased. Therefore, the object to be heated can be heated with high efficiency.

  In the induction heating furnace in each aspect of the present invention described above, it is preferable that the rotating shaft that connects the rotating body and the rotation driving source is arranged in a direction along the direction of the magnetic flux in the space region. In this way, there is an effect that the magnetic flux density can be locally changed without changing the total amount of magnetic flux in the space region.

  The heating method using the induction heating furnace in each aspect of the present invention described above includes a step of rotating the rotating body and a step of disposing at least a part of the object to be heated so as to face the rotating body. It is a heating method. In this way, when the rotating body rotates in the manner described above, an eddy current due to an electromagnetic induction effect is generated in the heated object, and the heated object can be heated while suppressing vibration. Moreover, the running cost of the whole induction heating furnace can be reduced by reducing energy loss.

  ADVANTAGE OF THE INVENTION According to this invention, the heating method using the induction heating furnace which suppressed the vibration which generate | occur | produces when heating and the said induction heating furnace can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each embodiment, portions having the same function are denoted by the same reference numerals, and the description thereof will not be repeated unless particularly necessary.

(Embodiment 1)
FIG. 1 is a schematic perspective view of an induction heating furnace according to Embodiment 1 of the present invention. 2 is a schematic cross-sectional view taken along line II-II in FIG. As shown in the schematic cross-sectional views of FIGS. 1 and 2, the induction heating furnace 100 has a structure in which a fixed iron core 11 as a fixed body connected to a DC power source 13 via a coil 12 is a base. Further, in the space 20 that is a region where the fixed iron core 11 is divided, the object to be heated 16 to be heated and at least part of the main surface of the object to be magnetized so as to oppose the main surface of the object to be heated 16. A rotating body 24 including a body material is disposed.

  FIG. 3 is a schematic view showing the main surface of the rotating body. As shown in FIGS. 1 and 3, the rotating body 24 includes a disk-shaped base body 15 having a certain thickness, for example, and a magnetic material 14. For example, a resin is used as the material of the base body 15 forming the rotating body 24. However, a nonmagnetic material such as brass, aluminum, or stainless steel can be used instead of the resin. Part of the main surface of the base body 15 includes the magnetic material 14. The magnetic material 14 is preferably made of a material containing, for example, iron, cobalt, and nickel. The magnetic material 14 may exist in a state of being coated (coated) on the main surface of the base body 15, or from one main surface of the base body 15 to the other main surface facing the one main surface. It may exist so as to penetrate to the surface in the thickness direction. As shown in FIG. 3, the magnetic material 14 is not disposed in a region other than a part on the main surface of the base body 15 described above.

  As shown in FIGS. 1 and 2, the rotating body 24 is connected to a motor 18 as a rotational drive source through a rotating shaft 19 that penetrates the inside of the fixed iron core 11. The motor 18 rotates the rotating body 24 in the direction along the main surface about the rotating shaft 19. The rotating shaft 19 is preferably arranged in a direction along the direction of magnetic flux in the region of the space 20. 1 and 2, the direction of the magnetic flux in the region of the space 20 is a direction along the vertical direction of the paper. In this way, as described above, there is an effect that the magnetic flux density can be locally changed without much changing the total amount of magnetic flux in the region of the space 20.

  As described above, the fixed iron core 11 has the space 20 in which the fixed body is divided. For this reason, it is preferable that the main surface of the fixed iron core 11 existing in the direction along the vertical direction has, for example, an approximately C shape as shown in FIGS. 1 and 2.

  FIG. 4 is a schematic view showing a state in which a thin sheet of silicon steel sheet is laminated in a plurality of layers in order to form a fixed iron core. As will be described later, in the induction heating furnace 100 of the present invention, the magnetic flux inside the fixed iron core 11 or on the extension region of the fixed iron core 11 does not change with time due to the direct current flowing through the coil 12. For this reason, since eddy current does not flow through the fixed iron core 11, the fixed iron core 11 may be formed using, for example, electromagnetic soft iron.

  However, in actuality, even in the fixed iron core 11, the magnetic flux may locally vary in time, particularly in a region near the surface facing the space 20 where the fixed body is divided. Therefore, as shown in FIG. 4, the fixed iron core 11 is preferably formed by laminating a thin plate of the silicon steel plate 28 in a plurality of layers. Note that the fixed iron core 11 may be formed as follows. First, a portion forming the core of the fixed iron core 11 is formed using an inexpensive iron lump. And in the area | region of the surface vicinity which opposes the space 20 where the fixed iron core 11 was parted, what processed the silicon steel plate 28 into the desired shape is laminated | stacked on a some layer. The fixed iron core 11 may be formed by the above procedure.

  A coil 12 connected to a DC power source 13 is wound around a region of the fixed iron core 11 that faces the space 20 forming the C-shape when viewed in the horizontal direction. The fixed iron core 11 and the DC power source 13 are electromagnetically connected via the coil 12. That is, since the current flowing through the coil 12 is a direct current, the direction and strength of the magnetic flux formed inside the fixed iron core 11 is constant.

  As the coil 12, for example, a copper coil may be used. However, when a direct current is passed through a copper coil, the coil generates heat, increasing the electrical resistance of the coil. Then, since the direct current flowing through the copper coil decreases, the efficiency of supplying the magnetic flux generated from the coil 12 into the region of the space 20 may deteriorate. Therefore, when using a copper coil, it is preferable to use a water-cooled copper coil provided with a facility for cooling the coil with cooling water, for example. If it does in this way, running cost can be reduced by reducing the electrical resistance of a coil and using the direct current which flows into a coil as energy for supplying magnetic flux to the space 20.

  However, as the coil 12, it is more preferable to use a superconducting coil instead of using a water-cooled copper coil. For example, the superconducting coil such as liquid nitrogen (not shown) is disposed inside a tank provided with a cooling medium that maintains the temperature below the critical temperature. As described above, when a superconducting coil is used as the coil 12 and a direct current is passed through the coil 12, almost no electrical resistance is generated inside the coil 12. For this reason, the coil 12 hardly generates heat. Alternatively, the amount of heat generated in the coil 12 can be minimized. As described above, if a superconducting coil is used as the coil 12 connected to the DC power source 13, the magnetic flux generated by the current flowing through the coil 12 can be supplied into the region of the space 20 with high efficiency.

  The region of the space 20 that the induction heating furnace 100 according to Embodiment 1 of the present invention constitutes has, for example, a height (distance between opposing end surfaces on both sides of the fixed iron core 11) of 100 mm and a width (lateral width of the space 20). When the current is 400 mm and the depth (depth of the space 20) is 500 mm, particularly when a direct current is passed through the coil 12, a superconducting coil is used as compared with the case where a water-cooled copper coil having the same weight (200 kg) is used as the coil 12. However, the accumulated cost when used for a long time can be greatly reduced.

  More specifically, the superconducting coil requires a higher initial capital investment than the water-cooled copper coil, but the running cost during long-term use is greatly reduced compared to the water-cooled copper coil. Therefore, if the accumulated costs when used for 3 years or more are compared, the superconducting coil is significantly reduced compared to the water-cooled copper coil.

  Here, a case where magnetic flux is supplied from the DC power source 13 to the inside of the fixed iron core 11 via the coil 12 is considered. A direct current flows through the coil 12. However, the magnetic flux in the fixed iron core 11 or on the extension region of the fixed iron core 11 does not change with time due to the direct current flowing in the coil 12. Therefore, the magnetic flux generated in the entire region of the space 20 by the direct current flowing through the coil 12 does not change with time.

  Further, the rotating body 24 is rotated by driving the motor 18 using a power source (not shown). Here, the rotating body 24 rotates in the region of the space 20 while maintaining an arrangement facing the end surfaces on both sides of the divided fixed core 11. At this time, a magnetic flux passing through the magnetic material 14 included in a part on the main surface of the base body 15 constituting the rotating body 24 exists in the space 20.

  However, as shown in FIGS. 1 and 2, the induction heating furnace 100 is configured such that the entire base body 15 constituting the rotating body 24 is accommodated in the region of the space 20. Therefore, even if the base body 15 rotates, the entire base body 15 is always accommodated in the region of the space 20. Further, as described above, the base body 15 rotates in the region of the space 20 while maintaining the arrangement facing the end surfaces on both sides of the divided fixed core 11. For this reason, even if the base body 15 rotates, the magnetic flux by the magnetic material 14 existing in the entire region of the space 20 does not change with time. As described above, in the induction heating furnace 100 according to Embodiment 1 of the present invention, the overall strength of the magnetic flux generated in the region of the space 20 does not change with time.

  Therefore, no cogging torque is generated in the fixed iron core 11 due to the attractive force accompanying the temporal change of the magnetic field. Since the cogging torque is not generated in the induction heating furnace 100 according to Embodiment 1 of the present invention, it is possible to suppress the occurrence of mechanical vibrations in the entire apparatus of the induction heating furnace 100.

  In the rotating body 24 of FIG. 3, the magnetic material 14 on the main surface of the base body 15 is circular and is regularly arranged at positions symmetrical to the center of the main surface of the base body 15. However, the shape and arrangement of the magnetic material 14 on the main surface of the base body 15 are arbitrary. As shown in the induction heating furnace 100, since the entire base body 15 is accommodated in the region of the space 20, the base body is independent of the shape and arrangement of the magnetic material 14 on the main surface of the base body 15. Even if 15 rotates, the magnetic flux in the magnetic material 14 existing in the entire region of the space 20 does not change with time.

  Further, the rotating body 24 is rotated by driving the motor 18 using a power source (not shown). Then, the magnetic material 14 contained in a part on the main surface of the base body 15 rotates in the region of the space 20, so that, for example, a certain distance from the rotating body 24 is formed in the region of the space 20. In a certain region on one main surface (opposing the base body 15) of the object to be heated 16 disposed so as to oppose the base body 15, the position on the surface of the base body 15 where the region opposes The rotation of the body 15 corresponds to a region including the magnetic material 14, corresponds to a region not including the magnetic material 14, or changes with time. This will be described in more detail below.

  FIG. 5 is a schematic diagram illustrating a state in which an object to be heated is moved so as to face a rotating rotating body. For example, as shown in FIG. 3, a rotating body 24 in which circular magnetic material 14 having the same diameter is arranged at regular intervals on the edge of the main surface of a base body 15 having a main surface that is disk-shaped. Consider the case of using it. In this case, if the base body 15 rotates in the region of the space 20 while maintaining the arrangement facing the both end surfaces of the divided fixed iron core 11, as shown in FIG. In this case, there are a magnetic locus 14 a that is a locus through which the magnetic material 14 passes by rotation and a non-magnetic locus 14 b that is not a locus of the magnetic material 14. Here, as shown by an arrow in FIG. 5, the object to be heated 16 is moved within the space 20 so as to be opposed to the base body 15 with a certain distance.

  Here, when a certain local region on the main surface of the object to be heated 16 is considered, the magnetic flux reaching the region of the base body 15 facing the magnetic body locus 14a on the main surface of the object to be heated 16 is It changes according to the phase of the rotating base body 15. Specifically, when a certain local region on the main surface of the object to be heated 16 is opposed to the magnetic body locus 14a of the rotating base body 15, depending on the phase of the rotating base body 15, The local region faces the region including the magnetic material 14 of the base body 15 or faces the region not including the magnetic material 14. Here, when the region on the main surface of the base body 15 opposed to the local region is changed from the region including the magnetic material 14 to the region not including the magnetic material 14 by the rotation of the base body 15, or the magnetic material. When changing from a region not including 14 to a region including 14, the magnetic flux reaching the local region of the object to be heated 16 changes.

  As described above, if the magnetic flux that reaches the local region of the main surface of the object to be heated 16 that faces the magnetic locus 14a changes with time, electromagnetic induction occurs in the local region. Eddy current is generated due to the effect. Therefore, the eddy current generates heat in the vicinity of the surface of the object to be heated 16, particularly in a local region of the object to be heated 16 that faces the magnetic locus 14 a. As a result, the article to be heated 16 can be heated.

  5, 1, and 2, the main surface of the object to be heated 16 has a rectangular parallelepiped shape, and the object to be heated 16 is moved to overlap the rotating body 24 facing the object 16. Yes. However, the induction heating furnace 100 according to the first embodiment of the present invention is used for induction heating of metal products used for hot forging, for example. Therefore, the shape of the metal product (object to be heated 16) is not necessarily a rectangular parallelepiped shape, and is used for a metal product having an arbitrary shape such as a circular shape, a strip shape, or a rectangular shape.

  Moreover, the to-be-heated material 16 is set as the structure accommodated in the area | region of the space 20 in FIG. However, with respect to the object to be heated 16, the region of the object to be heated 16 that faces the magnetic locus 14 a as long as it faces at least a part of the magnetic locus 14 a in FIG. 5 when the rotating body 24 rotates. Is heated by the generation of eddy current. Therefore, in the first embodiment of the present invention, the entire object to be heated 16 may not be stored in the area of the space 20.

  FIG. 6 is a schematic diagram showing the shape of a rotating body that can be considered as a modification of the rotating body of FIG. As shown in FIG. 6, the rotating body 25 has connecting rods 17 extending in four directions from the center of the rotating body, instead of the base body 15 of the rotating body 24 shown in FIG. 3, and ends of the connecting rods 17. The magnetic material 14 is connected to the part. Here, the magnetic material 14 in the rotating body 25 is circular in FIG. 6, but may be, for example, disk-shaped or spherical.

  Further, when the rotating body 25 shown in FIG. 6 is used for the induction heating furnace 100 instead of the rotating body 24 shown in FIG. 3, the entire rotating body 25 is accommodated in the region of the space 20. The size is preferred. In this way, the magnetic flux due to the magnetic material 14 existing in the entire area of the space 20 does not change with time even if the rotating body 25 rotates. As described above, in the induction heating furnace 100 according to the first embodiment of the present invention, even when the rotating body 25 is used instead of the rotating body 24, the overall strength of the magnetic flux generated in the region of the space 20 is temporally reduced. It does not change.

  However, as in the case of using the rotating body 24 described above, the magnetic flux reaching a certain local area on the main surface of the object to be heated 16 facing the rotating body 25 in the area inside the space 20 is temporal. To change. For this reason, in the said local area | region, the to-be-heated material 16 can be heated by generating the eddy current by an electromagnetic induction effect.

  FIG. 7 is a schematic diagram showing a shape of a rotating body that can be considered as a modification of the rotating body of FIG. As the rotating body used in the induction heating furnace 100 according to Embodiment 1 of the present invention, as in the rotating body 26 of FIG. A structure in which a hole for connecting the rotating shaft 19 to the portion may be provided. Although not shown, for example, two or more (a plurality of) rod-shaped (plate-shaped) magnetic material shown in the rotating body 26 of FIG. 7 is used to connect the rotating shaft 19 to the central portion of each major axis direction. A rotating body having a configuration in which holes are provided and each major axis direction is arranged at a certain angle such as a right angle and connected to the rotating shaft 19 may be used.

  Even when the rotating body 26 described above is used, the overall strength of the magnetic flux generated in the region of the space 20 does not change with time as in the case where the rotating bodies 24 and 25 described above are used. . Further, the magnetic flux that reaches a certain local area on the main surface of the object to be heated 16 that faces the rotating body 25 in the area inside the space 20 changes with time. For this reason, in the said local area | region, the to-be-heated material 16 can be heated by generating the eddy current by an electromagnetic induction effect.

(Embodiment 2)
FIG. 8 is a schematic cross-sectional view similar to FIG. 2, regarding the induction heating furnace in the second embodiment of the present invention. As shown in FIG. 8, the induction heating furnace 200 according to the second embodiment of the present invention has basically the same mode as the induction heating furnace 100 shown in FIGS. However, in the induction heating furnace 200, for example, when the above-described rotating body 24 is used as the rotating body, not only the rotating shaft 19 connected to the motor 18 but also the main surface of the rotating body 24 to which the rotating shaft 19 is connected. The main surface on the opposite side is also fixed to one end surface of the fixed iron core 11 by the rotating rod 29. In this way, the rotating body 24
Is supported by the rotary shaft 19 or the rotary rod 29 from both main surfaces, so that, for example, the rotary body 24 of the induction heating furnace 100 is supported by only the rotary shaft 19 from one main surface. As compared with the above, the rigidity of the rotating body 24 can be improved.

  If induction heating furnace 200 in Embodiment 2 of the present invention is used, as shown in FIG. 8, the object to be heated 16 has a rotating rod near the center in the space 20 so as not to interfere with rotating rod 29. It can be arranged only in an area away from the area where the 29 exists. In this case, it is preferable that at least a part of the main surface of the object to be heated 16 be opposed to the magnetic locus 14a shown in FIG. 5 when the rotating body 24 is rotated. In this way, the region of the object to be heated 16 facing the magnetic locus 14a is heated by the generation of eddy current. In the second embodiment of the present invention, for example, the rotating body 25 or the rotating body 26 may be used instead of the rotating body 24.

  FIG. 9 is a schematic cross-sectional view similar to FIG. 2 relating to an induction heating furnace when another object to be heated is heated in the second embodiment of the present invention. As shown in FIG. 9, when the object 16 to be heated has, for example, a concentric shape (donut shape) with a part missing, or a C-shaped shape, this is not affected by the interference of the rotating rod 29. If it can arrange | position in the desired location inside 20, it can be said that it is a preferable shape which can be heated using the induction heating furnace 200. FIG. Alternatively, when the object to be heated 16 is made of a metal material having a band shape or a rod shape, for example, even if the area where the object to be heated 16 can be arranged is narrow in the area inside the space 20, The object to be heated 16 can be arranged at a desired location inside the space 20 without receiving interference. Even in this case, it is preferable that at least a part of the main surface of the article to be heated 16 is opposed to the magnetic body locus 14a shown in FIG. 5 when the rotating body 24 is rotated. In this way, the region of the object to be heated 16 facing the magnetic locus 14a is heated by the generation of eddy current.

  The second embodiment of the present invention is different from the first embodiment of the present invention only in the points described above. That is, regarding the second embodiment of the present invention, the configurations, conditions, procedures, effects, and the like not described above are all in accordance with the first embodiment of the present invention.

(Embodiment 3)
FIG. 10 is a schematic cross-sectional view similar to FIG. 2 relating to the induction heating furnace in the third embodiment of the present invention. As shown in FIG. 10, the induction heating furnace 300 in Embodiment 3 of this invention is equipped with the aspect fundamentally the same as the induction heating furnace 200 shown in FIG. 8, FIG. However, in the induction heating furnace 300 shown in FIG. 10, for example, when the rotating body 24 described above is used as the rotating body, only a part of the area of the rotating body 24 is accommodated in the area of the space 20. Yes. Accordingly, the other part of the rotating body 24 (the region on the edge side of the circular main surface) protrudes outside the space 20.

  As shown in the induction heating furnace 300 of FIG. 10, when the rotary shaft 19 and the rotary rod 29 are connected to the fixed iron core 11 in the region near the center on both end faces of the fixed iron core 11, In some cases, the magnetic material 14 may be stored in the space 20. For example, this is the case where the magnetic material 14 is present in a region on the main surface of the base body 15 that is close to the center (stored in a region inside the space 20). In this case, the same effects as those of the induction heating furnace 200 described above can be obtained.

  FIG. 11 is a schematic cross-sectional view similar to FIG. 2, relating to an induction heating furnace when another object to be heated is heated in Embodiment 3 of the present invention. An induction heating furnace 400 shown in FIG. 11 has basically the same mode as the induction heating furnace 300. Specifically, for example, when the above-described rotating body 24 is used as the rotating body, only a part of the area of the rotating body 24 is accommodated in the area of the space 20. However, in the case of the induction heating furnace 400, the rotating shaft 19 and the rotating rod 29 are connected to the fixed iron core 11 in a region away from the vicinity of the center on both end faces of the fixed iron core 11.

  Even in the configuration described above, it is preferable that the magnetic flux generated by the magnetic material 14 of the rotating body 24 in the region of the space 20 does not change with time when the rotating body 24 rotates. However, since the rotating body 24 is disposed at a position shifted from a position that is symmetric with respect to the area of the space 20, even if the rotating body 24 rotates, the magnetic flux in the entire area of the space 20 is temporally changed. It is difficult to arrange the magnetic material 14 so as to be constant.

  However, even in the case of the configuration of the induction heating furnace 400, if the magnetic material 14 is arranged so that the time change rate of the magnetic flux in the entire region of the space 20 can be suppressed within ± 50%, the space 20 The magnitude of the mechanical vibration generated in the apparatus (induction heating furnace 400) can be suppressed within an allowable range by the cogging torque due to the attractive force generated by the change of the magnetic flux in the entire region.

  FIG. 12 is a schematic diagram showing an example of the arrangement of the magnetic material of the rotating body that can suppress the time change rate of the magnetic flux in the entire region of the space within ± 50%. In the rotating body 27 shown in FIG. 12, with respect to the region near the edge of the main surface of the base body 15, the magnetic material 14 is applied to the entire circumference having a constant distance from the center in the region closer to the edge. The ratio of a certain area is small, and as the distance from the edge approaches the center, the ratio of the area where the magnetic material 14 is applied to the entire circumference with a constant distance from the center increases. A magnetic material 14 is applied to almost the entire surface in a region near the center of the main surface. As a result, as shown in FIG. 12, the entire magnetic material 14 of the rotating body 27 has a substantially star shape.

  Like the rotating body 27, the ratio of the region including the magnetic material 14 is monotonously changed according to the distance from the center of the circle forming the main surface of the rotating body. If it does in this way, the time change rate of the magnetic flux in the whole area | region of the space 20 at the time of rotating the rotary body 27 installed in the induction heating furnace 400 of FIG. 11 can be suppressed within +/- 50%. If the time change rate of the magnetic flux is within ± 50%, even if cogging torque due to the change in magnetic resistance is generated, the mechanical vibration generated in the induction heating furnace 400 is sufficiently higher than the level at which the apparatus is damaged, for example. And can be kept within an allowable range that does not affect the lifetime of the apparatus. The induction heating furnace 400 is different from the induction heating furnace 300 only in the above points.

  FIG. 13 is a schematic cross-sectional view similar to FIG. 2 relating to an induction heating furnace in a case where an object to be heated of another shape is heated in the third embodiment of the present invention. An induction heating furnace 500 shown in FIG. 13 has basically the same mode as the induction heating furnace 400 shown in FIG. However, in the induction heating furnace 500, the rotating shaft 19 and the rotating rod 29 exist outside the space 20 (inside the fixed iron core 11).

  When the entire structure of the object to be heated 16 can be accommodated in the area of the space 20 by adopting a configuration in which the rotating rod 29 exists outside the space 20 as in the induction heating furnace 500, the object to be heated 16 rotates. There is no interference from the rod 29. Therefore, when the induction heating furnace 500 is used, the heated object 16 having a larger size can be heated in a shorter time than when the induction heating furnace 400 is used. The induction heating furnace 500 is different from the induction heating furnace 400 only in the above points.

  The third embodiment of the present invention is different from the first or second embodiment of the present invention only in the points described above. That is, regarding the second embodiment of the present invention, the configurations, conditions, procedures, effects, and the like not described above are all in accordance with the first or second embodiment of the present invention.

(Embodiment 4)
FIG. 14 is a schematic cross-sectional view similar to FIG. 2 regarding a fixed iron core used in the induction heating furnace in the fourth embodiment of the present invention. The fixed iron core 11 in FIG. 14 is the same as the fixed iron core 11 in each of the induction heating furnaces 100, 200, 300, 400, 500 in the first to third embodiments of the present invention described above. However, in the fixed iron core 11 in FIG. 14, the coil 12 is wound in a region within 300 mm from one (upper) end surface (surface facing the space 20) of the fixed iron core 11. Thus, the position where the coil 12 is wound on the fixed iron core 11 is different from the fixed iron core 11 in the induction heating furnace in the first to third embodiments of the present invention.

  As described above, when a DC current supplied from the DC power supply 13 is supplied to the coil 12, a magnetic flux is generated inside the coil 12 or on the extending region in the longitudinal direction of the coil 12. Using this magnetic flux, the object to be heated 16 existing in the space 20 is heated. Therefore, it is more preferable that the coil 12 which is a magnetic flux generation source is wound in a region near the space 20 in which the magnetic flux is to be supplied in the fixed iron core 11. This is because when the coil 12 is arranged in a region close to the space 20, the magnetic flux generated by the coil 12 when a direct current is passed through the coil 12 can be efficiently supplied into the region of the space 20. is there. As a result, the object to be heated 16 disposed in the region of the space 20 can be heated more efficiently.

  The arrangement of the coil 12 shown in FIG. 14 may be adopted for any of the induction heating furnaces 100, 200, 300, 400, and 500 according to the first to third embodiments of the present invention described above. In FIG. 14, the coil 12 is wound within a region within 300 mm from the upper end surface of the fixed iron core 11, but the coil 12 is within a region within 300 mm from the lower end surface of the fixed iron core 11. It may be wound.

  FIG. 15 is a schematic cross-sectional view similar to FIG. 2 regarding a fixed iron core having another configuration used in the induction heating furnace in the fourth embodiment of the present invention. In the above-described fixed iron core 11 in FIG. 14, the coil 12 is wound in a region within 300 mm from one end face of the fixed iron core 11, whereas the fixed iron core 11 in FIG. 15 faces the space 20. The coil 12 is wound in a region within 300 mm from each of the pair of surfaces (both end surfaces).

  Thus, if it arrange | positions in the area | region within 300 mm from the both ends of the C-shaped fixed iron core 11 so that the two coils 12 may pinch | interpose the space 20, it will be made to supply in the area | region of the said space 20. The magnetic flux that can be generated is twice that in the case of FIG. Therefore, the article to be heated 16 can be heated more efficiently.

  The arrangement of the coil 12 shown in FIG. 15 may also be adopted for any of the induction heating furnaces 100, 200, 300, 400, and 500 according to the first to third embodiments of the present invention described above.

(Embodiment 5)
FIG. 16 is a schematic perspective view of an induction heating furnace in the fifth embodiment of the present invention. FIG. 17 is a schematic sectional view taken along line XVII-XVII in FIG. In induction heating furnace 600 shown in the schematic cross-sectional views of FIGS. 16 and 17, U-shaped permanent magnet 21 corresponds to fixed iron core 11 as a fixed body in Embodiments 1 to 4 of the present invention described above. To do. For example, a permanent magnet made of a bulk superconductor is preferably used as the permanent magnet 21. By using the bulk superconductor, the amount of heat generated in the permanent magnet 21 can be minimized. Ordinary iron permanent magnets may be used. Rotating body as a rotating body similar to the first to fourth embodiments of the present invention described above with reference to FIGS. 16 and 17, sandwiched between regions near both ends of the U-shape of permanent magnet 21 used as a fixed body 24 and a region where the article 16 to be heated is disposed is a space 20. This space 20 has the same function as the space 20 of each induction furnace in the first to fourth embodiments of the present invention.

  The magnetic flux has the same strength as the magnetic flux generated by passing a direct current through the coil. For this reason, in the induction heating furnace 600, it is not necessary to use a coil. Further, since a permanent magnet is used, a magnetic flux having a constant direction and strength can always exist in the region of the space 20. In this sense, even when the permanent magnet 21 made of a bulk superconductor is used as means for supplying the magnetic flux to the space 20, the same effect as when the coil is used is obtained.

  Rather, if the permanent magnet 21 is used as the fixed body, a high-density magnetic flux is supplied from both ends of the U-shape of the permanent magnet 21 (both ends of the divided region of the permanent magnet 21). For this reason, the magnetic flux in the space 20 in which the rotating body 24 and the object to be heated 16 are arranged, which forms the divided area of the permanent magnet 21, is, for example, the arrangement of the coil 12 in the above-described fourth embodiment of the present invention. The situation is similar to the case. Specifically, the situation in which the magnetic flux is supplied to the space 20 using the permanent magnet 21 is that the coil 12 is wound in a region close to the space 20 where the magnetic flux is to be supplied as disclosed in the fourth embodiment. Similar to the situation. Therefore, by using the permanent magnet 21 as the fixed body, the magnetic flux that the permanent magnet 21 supplies to the entire area of the space 20 can be increased. Therefore, the object to be heated 16 can be heated with high efficiency.

  The fifth embodiment of the present invention differs from the first to fourth embodiments of the present invention only in the points described above. For example, as shown in FIG. 16 and FIG. 17, in the region to be the space 20, the rotating body 24 and the object to be heated 16 are the same as the space 20 of each induction heating furnace described in the first to fourth embodiments of the present invention. Is placed. The rotating body 24 is connected to a motor 18 as a rotational drive source through a rotating shaft 19 that penetrates the interior of the permanent magnet 21. For example, instead of the rotating body 24, the above-described rotating bodies 25, 26, and 27 may be used as the rotating body.

  In FIGS. 16 and 17, the rotating body 24 is fixed only to the rotating shaft 19 connected to the motor 18, similarly to the rotating body 24 disclosed in the first embodiment of the present invention. However, for example, as disclosed in the second embodiment of the present invention, not only the rotating shaft 19 connected to the motor 18 but also the main surface of the rotating body 24 to which the rotating shaft 19 is connected. The main surface on the opposite side may also be fixed to one end surface of the fixed iron core 11 with the rotary rod 29.

  FIG. 18 is a flowchart showing the procedure of the heating method using the induction heating furnace according to the present invention. In the case where the object to be heated 16 is heated using any of the induction heating furnaces of the first to fifth embodiments described above, as shown in FIG. 18, the step shown in FIG. 6 described above in the step of rotating the rotating body (S10) is performed. The rotating body 24 is rotated as shown in FIG. And on the main surface of the base body 15 which comprises the rotary body 24, as shown in FIG. 6, the magnetic body locus | trajectory 14a which is a locus | trajectory through which the magnetic body material 14 passes by rotation, and the nonmagnetic body which is not a locus | trajectory of the magnetic body material 14 In a state where the object to be heated is arranged (S20) in a state where the locus 14b exists, at least a part of the object to be heated 16 is arranged so as to face the rotating body 24. Then, when the rotating body 24 rotates according to the above-described procedure, an eddy current due to the electromagnetic induction effect is generated in the object to be heated 16, and the object to be heated can be heated while suppressing vibration. Moreover, the running cost of the whole induction heating furnace can be reduced by reducing energy loss. It should be noted that the steps (S10) and (S20) described above may be performed in the reverse order.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is particularly excellent as a technique for heating an object to be heated with high efficiency while suppressing mechanical vibration generated during induction heating.

It is a schematic perspective view of the induction heating furnace in Embodiment 1 of the present invention. It is a schematic sectional drawing in line segment II-II of FIG. It is the schematic which shows on the main surface of a rotary body. It is the schematic which shows the state which laminates | stacks the thin plate of a silicon steel plate in a some layer in order to form a fixed iron core. It is the schematic which shows the state which moves a to-be-heated material so that the rotating body which rotates may be opposed. It is the schematic which shows the shape of the rotary body considered as a modification of the rotary body of FIG. It is the schematic which shows the shape of the rotary body considered as a modification of the rotary body of FIG. It is the same schematic sectional drawing as FIG. 2 regarding the induction heating furnace in Embodiment 2 of this invention. It is the same schematic sectional drawing as FIG. 2 regarding the induction heating furnace at the time of heating the to-be-heated object of another shape in Embodiment 2 of this invention. It is the same schematic sectional drawing as FIG. 2 regarding the induction heating furnace in Embodiment 3 of this invention. It is the same schematic sectional drawing as FIG. 2 regarding the induction heating furnace at the time of heating the to-be-heated object of another shape in Embodiment 3 of this invention. It is the schematic which shows an example of arrangement | positioning of the magnetic body material of a rotary body which can suppress the time change rate of the magnetic flux in the whole area | region of space within +/- 50%. It is the same schematic sectional drawing as FIG. 2 regarding the induction heating furnace at the time of heating the to-be-heated object of another shape in Embodiment 3 of this invention. It is a schematic sectional drawing similar to FIG. 2 regarding the fixed iron core used for the induction heating furnace in Embodiment 4 of this invention. It is a schematic sectional drawing similar to FIG. 2 regarding the fixed iron core of another structure used for the induction heating furnace in Embodiment 4 of this invention. It is a schematic perspective view of the induction heating furnace in Embodiment 5 of this invention. It is a schematic sectional drawing in the line segment XVII-XVII of FIG. It is a flowchart which shows the procedure of the heating method using the induction heating furnace which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 Fixed iron core, 12 coils, 13 DC power supply, 14 Magnetic material, 14a Magnetic material locus, 14b Nonmagnetic material locus, 15 Base body, 16 Heated object, 17 Connection rod, 18 Motor, 19 Rotating shaft, 20 Space, 21 permanent magnet, 24 rotating body, 25 rotating body, 26 rotating body, 27 rotating body, 28 silicon steel plate, 29 rotating rod, 100 induction heating furnace, 200 induction heating furnace, 300 induction heating furnace, 400 induction heating furnace, 500 induction Heating furnace, 600 induction heating furnace.

Claims (10)

A stationary body connected to a DC power source;
A rotating body including a magnetic material in a part on the main surface, which is disposed in a space forming a region where the fixed body is divided;
A rotation drive source for rotating the rotating body,
By rotating the rotating body, the magnetic flux density is locally changed in time in the space area, but the magnetic flux intensity does not change in time in the entire space area. .   The induction heating furnace according to claim 1, wherein the whole of the rotating body is accommodated in an area of the space. A stationary body connected to a DC power source;
A rotating body including a magnetic material in a part on the main surface, which is disposed in a space forming a region where the fixed body is divided;
A rotation drive source for rotating the rotating body,
By rotating the rotating body, the magnetic flux density is locally changed in time in the space area, and the time change rate of the magnetic flux intensity in the space area is within ± 50%. heating furnace.   The induction heating furnace according to claim 3, wherein only a partial area of the rotating body is accommodated in the area of the space.   The induction heating furnace according to any one of claims 1 to 4, wherein a main surface of the fixed body forms a C-shape by forming the space.   The induction heating furnace according to any one of claims 1 to 5, wherein the fixed body is formed by laminating silicon steel plates in a plurality of layers.   The induction according to any one of claims 1 to 6, wherein the DC power supply and the fixed body are connected to each other by winding a coil connected to the DC power supply in a partial region of the fixed body. heating furnace.   The induction heating furnace according to claim 7, wherein the coil is arranged by being wound in a region within 300 mm from at least one of a pair of surfaces facing the space of the fixed body.   The induction heating furnace according to any one of claims 1 to 8, wherein a rotating shaft that connects the rotating body and the rotation drive source is disposed in a direction along a direction of magnetic flux in the space region. . A heating method using the induction heating furnace according to any one of claims 1 to 9,
Rotating the rotating body;
And a step of arranging at least a part of the object to be heated so as to face the rotating body.

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